WO1999024852A1 - Hologram element polarization separating device, polarization illuminating device, and image display - Google Patents

Abstract

An image display serving to the maximum the function of effectively increasing the numerical aperture of a microlens array formed on an image displaying element and displaying a highly uniform, bright image with a high projection efficiency, characterized in that hologram elements (12-14) fabricated by allowing the object light which is a generally parallel beam to interfere with the reference light which has a wave front approximately equivalent to that of the output light beam from illuminating means for collecting and propagating a first light beam emitted from light emitting means, the object light is a generally parallel object beam is used, so that the image display is provided with means for illuminating the hologram elements, and image display displaying elements (6-8) for displaying an image by modulating the output light beams from the hologram elements, and that the image displaying element has microlens corresponding to the respective pixels, and each microlens has a function of focusing the incident beam almost onto an opening portion of a pixel.

Description

 Description Holographic element, polarized light separating element, polarized illumination device and image display device

TECHNICAL FIELD The present invention relates to an image display device that displays a bright, high-quality screen, and a hologram element used for the image display device.

 The present invention also relates to a polarization separation element for separating an incident light beam into different polarization components, and a projection type image display device configured by using the same, which projects and displays an image.

 In addition, a polarization illuminator that uses a polarization splitter to obtain uniform illumination light with a uniform polarization direction, and a projection type that modulates the polarized light emitted from the polarization illuminator with a light valve to enlarge and display an image It relates to a display device.

 In addition, a monitor for displaying images, a display device for personal digital assistants, a head-up display for in-vehicle use or personal use, and an image display device used for road traffic signs or information display, and for illumination light Lighting equipment.

In addition, an optical head for recording and reading information recorded on an optical storage medium such as an optical disk or a magneto-optical disk using a laser beam, and an optical pickup. The present invention relates to an optical information processing device including a pump and the like and a diffractive optical element used therein. Background technology Projection-type image display devices that modulate the brightness of these lights with image display elements and enlarge and project them on a screen are being developed (for example, O-Plus, August, 1993) No. 58-101).

FIG. 1 shows a configuration example of a conventional general image display device using a liquid crystal panel as image display means. The output light 3 from the lamp 2 is reflected by the reflector 14, and the output light beam 5 is condensed and propagated by the condensing optical system (not shown), and the dichroic light is separated for color separation. The liquid crystal panel 1 is separated into the three primary colors of red, green and blue by the loudspeaker mirrors 12 and 13 and passes through the total reflection mirror 14 and the capacitor lens 15. _6-0 that accounted not enter the 1 8

 The output light modulated by the liquid crystal panels 16 to 18 is supplied to a dichroic prism (not shown) for color synthesis or a dichroic mirror 19 , 20 and the total reflection mirror 14, and are enlarged and projected on a screen (not shown) by the projection lens 9.

 The liquid crystal panels 16 to 18 etc. are mainly classified into a transmission type and a reflection type, and both are incident through a polarizing plate or a polarizing beam splitter (hereinafter abbreviated as PBS). An image is displayed by modulating a specific linearly polarized light by a liquid crystal material.

The liquid crystal panels 16 to 18 are generally active matrices in which thin-film transistors (hereinafter abbreviated as TFTs) are arranged in each pixel as switching elements for driving each pixel. The TFT method is the mainstream, and the TFT is generally formed of polycrystalline polysilicon. FIG. 2 shows a configuration example of another conventional general image display device. After the output light from the lamp 22 is reflected by the reflector 23, an integration consisting of the first fly-eye lens 24 and the second fly-eye lens 25 is performed. Propagated by the turning back mirror 29, and the dike for color separation The three primary colors of red, green, and blue are separated by the mouth mirrors 30 and 31 and are incident on the image display elements 35 to 37.

 The image display elements 33 to 35 are broadly classified into a transmission type in which the incident light flux is modulated while transmitting the image display element and a reflection type in which the incident light flux is modulated while being reflected and outputted. In addition, the modulation method is roughly classified into a polarization type that changes the polarization state of the incident light beam and a dispersion type that modulates by scattering the incident light beam.

 In a polarization type image display device, a specific linearly polarized light incident through a polarizing plate or a polarizing beam splitter (hereinafter abbreviated as PBS) is used for both a transmission type and a reflection type. An image is displayed by modulating with a liquid crystal material. In the scattering type image display device, both the transmission type and the reflection type display black by scattering the incident light beam, and display white by outputting the incident light beam without scattering. 1 and 2 show a configuration using three image display elements (hereinafter abbreviated as a three-panel type). However, as described later, a method of displaying a single image with one image display element (hereinafter referred to as a three-panel type) , Abbreviated as veneer type). Lamps with high luminous efficiency, small luminous volume, high brightness, and high color rendering properties are required for lamps 2, such as metal halide lamps, xenon lamps, and ultra-light lamps. High-pressure mercury lamps are used. As the reflector 3 etc., a parabolic mirror, an ellipsoidal mirror, a spherical mirror, etc. are used because the reflected luminous flux is easily used effectively. It is often located at the focal point or first focal point or center of the reflector.

 In recent image display devices, when displaying an all-white signal,

(1) Make the brightness of the central part and the peripheral part of the projected image uniform. ,

 (2) Improve the projection efficiency (lumen / watt) defined as the value obtained by dividing the total luminous flux (lumen) projected by the lamp power consumption (bit).

This is the main task of the development, (1) by the introduction of Integrate, and (2) by the combination of Integre and the small high-intensity lamp of the luminous body. Alternatively, in an image display device using a polarization display device such as a liquid crystal panel as an image display device, a solution is attempted by further combining a polarization conversion element. Many studies have also been made on improving the projection efficiency by forming a micro lens on a liquid crystal panel.

 Next, the integrator will be described. Integral is defined as a two-dimensional micro lens as disclosed in, for example, Japanese Patent Application Laid-Open No. 3-111806 and Japanese Patent Application No. 5-3465957. It is configured by combining two types of fly's eye lenses that are arranged and configured. Figure 4 shows a specific example of the configuration of the integration. This is to improve the uniformity of the illuminating light by dividing the output luminous flux from the light source into a plurality of regions and superimposing them on the illuminated object.

The output light beam of the lamp 42 is reflected by the reflector 43 and then enters the first fly-eye lens 44. With the reflector 43 and the first fly-eye lens 44, the image of the illuminator of the lamp 42 corresponds to each lens of the first fly-eye lens 44. The second fly's eye to be formed forms an image on each of the lenses 4 and 5. Each lens of the second fly-eye lens 45 is configured such that an image of each lens constituting the first fly-eye lens 44 is formed on the image display element 47. ing. If necessary, a relay lens and an auxiliary lens are arranged between the second fly's eye lens and the image display device. The basic function as a grainer does not change.

 According to the above configuration, the image formed by the respective lenses of the second fly-eye lens 45 on the image display element 47 has a large luminance distribution output from the reflector 43. The output light beam is divided by each lens of the first fly-eye lens 44, and the result is obtained by superimposing them on the image display element 47. With this principle, it is possible to increase the brightness of the peripheral part of the projected image relative to the central part of the image to 70% or more.

Also, with the introduction of the integration, the projection efficiency of the image display device can be improved. Generally, the light flux reflected by the reflector 43 is a force ^s that is substantially circular, and the image display element 37 is, for example, a 4: 3 rectangle (or a 16: 9 rectangle). Therefore, when illuminating the image display element 47 in a circular shape, only the area ratio of the rectangle inscribed in the circle was effectively used. This is called rectangle conversion efficiency, and when an image display element 47 (of an aspect ratio) having a 4: 3 rectangle as its outer shape is used, the rectangle conversion efficiency was about 61%.

 However, the opening shape of the lens used for the first fly-eye lens 44 of the integration is disclosed in FIG. 2 of Japanese Patent Application Laid-Open No. 5-346557. Thus, by arranging as 4: 3, it is possible to improve to about 80%.

However, as disclosed in FIG. 2 of Japanese Patent Application Laid-Open No. 5-346557, the shape of the lens used for the first fly-eye lens 4 of the integret can be changed, for example. In addition to making the shape of the image display element similar to 4: 3, by densely forming each lens of the first fly-eye lens in a circular illumination area, The rectangle conversion efficiency can be improved to about 80%.

Next, the polarization conversion element will be described. The polarization type liquid crystal panel The image display device used has a drawback that only the polarized light component in a specific direction can be effectively used in the output light of the lamp. There was a problem that a large light source had to be used. A polarization conversion element has been developed to solve this problem. It effectively converts to a polarization component having a plane of orthogonal polarization.

 The polarization conversion element is disclosed in, for example, JP-A-5-107505, JP-A-6-22094, JP-A-7-294096, and JP-A-8-208. Although many are disclosed in Japanese Patent Application Publication No. 234245 and Japanese Patent Application Publication No. Hei 9-110593, they basically consist of a combination of a polarization splitting means and a polarization plane rotating means.

 FIG. 3 shows a configuration diagram of a general polarization conversion element 38. Non-polarized light (randomly polarized light beam) 62 is polarized by the polarization separating means 60 so that the polarization components are orthogonal to each other, that is, P-polarized light (parallel to the paper surface which is transmitted without being reflected by the polarization separating means). Light flux with polarization direction) 6 3 ', S-polarized light

(A light beam reflected by the polarization separation means and having a polarization direction perpendicular to the paper surface) is separated into 64, and only the S-polarized light 64 is reflected by the reflection means 60 (in general, the polarization separation means 60). It is based on the principle that the light is reflected by the same type of film) and converted into P-polarized light 41 by the polarization plane rotation means 61.

 In recent years, in many cases, a combination with a lens array 66 is used, and the above five reference examples can also be used in combination with a lens array.

Next, a liquid crystal panel formed with a micro lens will be described. In a normal image display device, a TFT for driving each pixel is formed for each pixel. Therefore, the portion of the pixel where the TFT is formed cannot transmit light. That is, there is a disadvantage that the ratio of the area through which light can actually pass to the area of each pixel (aperture ratio) is small.

 This is even more pronounced in high-resolution image display devices, where the aperture ratio is about 56% in an image display device in which 102.times.768 pixels are formed on a 1.3-inch diagonal panel. When the same number of pixels are formed on a 0.9-inch diagonal image display element, it is at most about 40%. If the number of pixels is further increased to increase the resolution, or if the number of pixels is the same and the size of the image display device is reduced, the aperture ratio is significantly reduced, and as a result, The projection efficiency will decrease.

 Therefore, for example, Japanese Unexamined Patent Application Publication Nos. Hei 11-21826, Hei 3-14092, and Hei 4-251221 disclose in many reference examples. As shown in the figure, a micro lens is formed on the glass substrate on the entrance side, and one micro lens is assigned to each pixel. It is considered that the incident light is focused only on the area where the light can be reflected, and the effective aperture ratio is improved.

 Also, a single-panel image display device using one image display element has been developed. The single-panel type requires fewer image display elements than the three-panel type and simplifies the configuration of the optical system, thus realizing low cost, which is important for practical use of image display devices. I can do it. In addition, effects such as reduction of the weight of the set and elimination of the need for a color comparator can be expected.

For example, in a three-panel system, the color compensating means that the output of the corresponding pixel of each image display element is aligned on a screen. Increase and adjustment This is costly due to the time required.

 On the other hand, the single-panel type has a disadvantage that the projection efficiency is lower than that of the three-panel type. For example, when a color filter is provided inside, the light intensity is reduced to 1/3 in principle and the image becomes dark. This is because while the three-panel system can use the three primary colors separated by color with little absorption, the color filter transmits only the luminous flux in the specific wavelength band, and This is because light in the wavelength band is absorbed or reflected and does not enter the pixel.

 Therefore, for example, “Nikkei Electronics”, January 30, 1995, page 169, page 173 (hereinafter abbreviated as Reference Example 1), Japanese Patent Application Laid-Open No. H08-29250 No. 6 (hereinafter abbreviated as Reference Example 2), FIG. 14 of Japanese Patent Application Laid-Open No. Hei 9-110589 (hereinafter abbreviated as Reference Example 3), “Nikkei Electronics” 1 FIG. 4 (a) (hereinafter abbreviated as Reference Example 4), page 18, page 19, October 21, 1996, Japanese Unexamined Patent Publication No. Hei 6 — 2223 61 (hereinafter referred to as Reference Example) It has been proposed to improve the projection efficiency by separating white light into three primary colors and then injecting each primary color into the corresponding pixel, as disclosed in a number of such methods. I have.

 Each of the above reference examples includes a color separation unit that separates white light into three primary colors, and an optical path conversion unit that causes the separated luminous flux to enter each corresponding pixel. As disclosed in Reference Examples 1, 2, and 3, the color separation means is a dike aperture mirror (hereinafter, referred to as a different type) which is arranged at different angles with respect to the optical axis as disclosed in Reference Examples 1, 2, and 3. In many cases, a tilt angle mirror (abbreviated as a dichroic mirror) is used, and micro-lens arrays (Reference Example 1) and hologram lens arrays (Reference Example 2) are used as optical path conversion means. , Cylindrical lenses (Reference Example 3), etc.

Also, for example, as disclosed in Reference Examples 4 and 5, hologram elements In some cases, a diffractive optical element such as a photomask is used as both a color separation unit and an optical path conversion unit.

 However, the conventional image display device as described above has the following problems.

 In order to utilize the functions of the integration device and the polarization conversion element effectively, it was necessary to use a high-intensity lamp with a small luminous body. The reasons are briefly described below. In the night of the integration, each lens constituting the first fly-eye lens (hereinafter, abbreviated as the first lens group) is replaced with each corresponding lens of the second fly-eye lens. A real image of the illuminant is formed on a lens (hereinafter abbreviated as a second lens group). At this time, if an image larger than the aperture of the second lens group is formed, an effective image is formed. A luminous flux that is not transmitted to the display means is generated, resulting in a loss of projection efficiency. Therefore, the smaller the light emitter is, the smaller the above-mentioned propagation loss becomes, so that it is possible to make the integration function effectively.

 The above phenomena occur when the polarization display means is not used as the image display means, for example, in a polymer dispersion type liquid crystal panel or the light deflection disclosed in US Pat. No. 5,096,279. The same applies to the case where a type of image display means is used.

 Further, in the case of a polarization conversion element, for example, in the case where it is configured by a combination with the integration (in most practical cases), as in the case of the integration described above, the polarization separation means is used. The luminous flux must be focused only on For example, in the polarization separation element 58 shown in FIG. 14, the component that is incident on the reflection means 60 ′ provided with the polarization plane rotation means 61 adjacent thereto instead of the polarization separation means 60 is effective. It is not used for and loss occurs.

This is achieved by placing a polarization converter on the lamp side of the first fly-eye lens, The same applies to the case where the irradiation angle after the polarization separation is made different depending on the polarization component. Only the components must be incident. Therefore, in order to improve the efficiency of the polarization conversion element and, consequently, the projection efficiency, a small lamp of the luminous body is required. For example, when the polarization conversion element alone is irradiated with parallel light such as laser light and its efficiency is examined, for example, in the case of the element shown in Fig. 14, the transmittance of P-polarized light 63 is about 96 After the S-polarized light 64 enters the polarization separation element 58, the efficiency of conversion to the P-polarized light 63 by the polarization plane rotating means 61 is about 91%, which is extremely high. However, the efficiency of converting the unpolarized light 62 into the P-polarized light 63 is about 94%. In an image display device using a polarization display means, this efficiency can be defined as polarization utilization efficiency. However, even when a lamp with a light emitter length of as small as about 1.45 millimeters is used, the polarization utilization efficiency is reduced to less than about 80%, and the light emitter length is reduced to about 3 millimeters. The reason for using the lamps of the above is that the love drops to about 60%, and the polarization utilization efficiency without the polarization conversion element is 50%, which is not much different from the above lamp. This is due to the size of the luminous body.

Further, apart from the above reasons, a light source with a small luminous body is necessary even in combination with a reflector for effectively condensing the output light from the lamp. For example, consider the case where a parabolic mirror is used as a reflector. This parabolic mirror has a concave surface formed by rotating a parabola with a rotation axis coinciding with the optical axis as a reflection surface. Generally, a luminous body is installed near the focus of a parabola on the optical axis. The reason is that the luminous flux diverging from the focus of the parabola becomes a parallel ray after reflection on the paraboloid. However, since the luminous body of the actual lamp has a finite size, not a point, convergent light and divergent light are generated, resulting in loss. For these reasons, a small light emitter was essential. In other words, if a light emitter is extremely small and a lamp that can be regarded as a point light source is used, it will be possible to achieve extremely high projection efficiency by taking advantage of the inherent functions of the polarization conversion element in the integration described above. Conceivable.

 As described above, the size of the illuminant greatly affects the performance of the integrator and the polarization conversion efficiency of the polarization conversion element, but this is a problem when displaying a higher-luminance image. Is an important issue. For example, if the size is about 100 to 200 bits, the size of the luminous body is about 2 millimeters at most, and as described above, it functions as an integral element and a function of the polarization conversion element. However, if a higher output lamp is used, the illuminant becomes larger as the lamp output increases. Therefore, in an image display device using a low output lamp of about 100 to 200 Watts, a high projection efficiency of 6 lumens / watt is possible, but this is not possible. When the above high output lamps are used, only about 3 lumen / unit can be realized at most.

 In other words, even if an image display device having a total output of 600 lumens / monitor of 6 lumens / bit using a 100-port lamp can be realized, for example, For example, it has been difficult to realize an image display device having a light output of 1200 lumens using a 200-bit lamp. As described above, when trying to increase the projected luminous flux using a high-power lamp, the projection efficiency was significantly reduced.

In the combination of an integrator and a polarization conversion element, the development of a high-intensity lamp with a small illuminant has recently made it possible to achieve high projection efficiency. However, the integration evening An effective image is obtained when an image display element that forms a micro lens is combined, or when an image display element that forms a micro lens is combined with an integration element and a polarization conversion element. There was a problem that even if an attempt was made to improve the aperture ratio of the display element, a significant effect could not be obtained. The reason is briefly described below.

 In the first place, in order to increase the effect of improving the effective aperture ratio by the micro lens, the light beam incident on the micro lens must be substantially parallel to the optical axis. Is preferred. This is because a light beam that enters obliquely with respect to the optical axis of the microphone aperture lens enters other parts of the pixel than the aperture.

 By converging a light beam of a high-luminance lamp with a small luminous body by a parabolic mirror, a light beam that is almost parallel can be obtained, but in actual illumination optics, Since it is essential to use the above-mentioned integration or polarization conversion element, the luminous flux incident on the image display element, ie, the micro lens, is not necessarily a substantially parallel luminous flux.

Therefore, in spite of the fact that the effective aperture ratio can be ideally set to almost 100%, even if the micro lens is introduced in the above example, it is at most 1.2. Only an improvement of the reading ratio can be expected, and the effective aperture ratio is about 67% for a 1.3-inch diagonal image display device and about 55% for a 0.9-inch diagonal image display device. However, almost half of the light was lost. Similar phenomena also occur when a micro lens is used as the optical path changing means, as seen in the single-panel image display devices of Reference Examples 1, 2, and 3. That is, the angles of incidence of the three primary colors incident on the image display device are made different from each other by the dichroic mirrors with different inclination angles, and the image of each primary color is made different by one micro lens. When the light flux is incident on the pixel displaying the signal at a different angle, since the incident light flux is not a parallel light flux, Color mixing and reduced efficiency have been observed.

 For example, in the example disclosed in Reference Example 1, red or blue light flux is obliquely incident on a pixel that originally displays a green signal, for example, and an image with a color tone different from the original color is displayed. In addition, the luminous flux did not efficiently enter the aperture of the pixel, or the efficiency was low.

 As described above, in order to configure an image display device capable of displaying images with high projection efficiency and high brightness uniformity, the functions of the integration, the polarization conversion element, and the micro lens are required. Must be used effectively. Among them, the integrator is an essential optical element not only for ensuring the uniformity of the brightness of the image but also for performing the polarization conversion, but the lens is arranged two-dimensionally and has two flywheels. It had to be combined with a special eye lens, making it expensive and inviting cost up. In other words, the production of a mold and a glass material for duplicating the integret were expensive, and together with the projection lens occupied most of the cost of the optical system.

In addition, a specific distance was required to realize the function, and it was impossible to construct a compact optical system. In other words, in the conventional integrator, each lens constituting the first fly-eye lens has to focus an incoming light beam on each lens of the corresponding second fly-eye lens. . At the same time, each lens of the second fly-eye lens must form an image of each lens of the first fly-eye lens on the image display device. The magnification at that time is the ratio of the distance L1 between the first fly's eye lens and the second fly's eye lens and the distance L2 between the second fly's eye lens and the image display element, That is, it is determined by L2 / L1. On the other hand, in order to increase the rectangular conversion efficiency, the first fly's eye lens may be made smaller and densely arranged in a substantially circular output light beam from the reflector, but as a result, cost In addition to this, the magnification had to be increased, and L2 became large, so that a compact configuration could not be achieved. Also, it was not possible to construct an integrator with a single fly-eye lens.

 As described in detail above, the present invention provides a diffractive optical element for realizing high light use efficiency while maintaining uniformity of image brightness, and an image display device using the same. It does.

 In addition, the above problem is a problem that arises because a lens whose optical behavior is described by so-called geometric optics is used. The invention of the present application solves the above-mentioned problem by a diffractive optical element based on wave optics which is not restricted by such geometrical optics. Many examples are disclosed. However, these are completely different from the technical idea of the diffractive optical element of the present invention and the image display device using the same.

 For example, in Japanese Unexamined Patent Application Publication No. Hei 6-222,361 and Japanese Patent Laid-Open Publication No. Hei 9-73014 (hereinafter referred to as Conventional Example 1), white non-white light is hologram-programmed. A method for improving light use efficiency by converging each color component is disclosed. Also, for example, in Japanese Patent Application Laid-Open No. Hei 8-220656 (hereinafter referred to as Conventional Example 2), a hologram element is provided on the output side of a liquid crystal panel so that a principal ray of an output light beam of the liquid crystal panel is focused on an optical axis. An example is disclosed in which this is done in parallel.

However, the hologram disclosed in Conventional Example 1 is divided into minute regions, and each minute region has a light-collecting property. However, this merely focuses the luminous flux of the desired light on the corresponding pixel. It functions only as a micro-lens array having wavelength selectivity, and is a feature of the diffractive optical element of the present invention. The projection efficiency (light utilization efficiency) while maintaining the uniformity of the brightness of the projected image However, the diffractive optical element of the present invention is completely different from the technical concept of the present invention.

 In addition, the hologram in Conventional Example 2 is arranged on the output side (projection lens side) of the liquid crystal display element, and its function is to parallelize the output luminous flux of the liquid crystal display element output at a different angle for each color. This reduces the burden on the projection lens of specifications. Therefore, the hologram in Conventional Example 2 is completely different from the diffractive optical element of the present invention, which enhances the uniformity of illumination light incident on the liquid crystal panel, in its technical idea.

 Further, in an exposure apparatus used in the semiconductor manufacturing field, for example, as disclosed in Japanese Patent Application Laid-Open No. H10-70070 (hereinafter, Conventional Example 3), a light source from a light source is used. A method for separating an output light beam by a diffractive optical element is disclosed. In Conventional Example 3, the output light beam after separation is again incident on the optical integral, and is superimposed on the object to be illuminated by the lens system, so that the output light beam from the light source is simply separated. It is just that. In other words, in a projection optical system using quintuple illumination, it is only used to improve the projection resolution in consideration of the directionality of the circuit pattern, and the uniformity of the illuminance of the illumination light is very small. A secondary light source is formed by a lens array in which lenses are arranged two-dimensionally, and the secondary light source image is secured by superimposing it on a lighting object with a capacitor lens.

Japanese Patent Application Laid-Open No. 63-269700 (hereinafter referred to as Conventional Example 4) discloses a reference in which light incident on a hologram head is superimposed on a photosensitive material. . However, in Conventional Example 4, when two-beam interference exposure is performed, the crossing angle of the beams is changed while changing the angle. The aim is to achieve precise alignment, and there is no disclosure of improving illuminance uniformity by superimposing beams. Further, two types of apertures are provided for light incident on the hologram head, and the purpose is to obtain an interference image between them. It does not superimpose all light incident on the entire surface.

 As described above, in the conventional examples 1 and 2 in which the diffractive optical element is applied to the image display device, a hologram having a simple wavelength selectivity and a light condensing property, or a hologram having an output light flux of a liquid crystal display element is used. It merely discloses a holographic element that changes the angle. Further, in the conventional examples 3 and 4 in which incident light is separated by a diffractive optical element, only a method of improving the projection resolution by separating the light or a method of improving the alignment is disclosed. As described above, the technical idea of using the diffractive optical element as an integral feature to make the illuminance on the image display element uniform, which is a feature of the present invention, is different from the conventional example. Is a new one that has not been disclosed.

 Next, a conventional hologram element will be described.

 In recent years, a laser beam has been formed by causing two coherent light beams to interfere with each other, and the laser beam has been recorded on gelatin bichromate or a photopolymer, and the wavefront of the recorded light beam has been recorded. The development of holographic devices that can reproduce holograms is active.

 Examples of application fields of holographic elements include interference measurement, holographic optical elements, as described in References, Toshihiro Kubota, “Introduction to Holography”. There are optical information processing such as pattern recognition, and holographic display.

When a holographic element is applied to the field of image display, it is simply a third order. In addition to displaying the original image, various applications are being considered. In the following, examples of (1) an optical switch and (2) a direct-view type liquid crystal panel are described.

 First, the optical switch will be described. For example, in Japanese Patent Application Laid-Open No. 5-173131, which is a conventional example 1, a mixture of a polymer material that is cured by the wavelength of a light beam that forms an interference image and a liquid crystal that is not cured at the wavelength of the light beam is disclosed. An object is illuminated with an interference image, and a region composed of a cured polymer material and a region composed of an uncured liquid crystal are formed by so-called light-induced phase separation, and the uncured liquid crystal is controlled by an applied voltage. Thus, an optical switch for controlling the diffraction / straight traveling of an incident light beam is disclosed.

 A number of similar examples have been disclosed, including, for example, Applied Physics Letters, Vol. 64, No. 9, pp. 741-10776, In 1991 (hereinafter abbreviated as Conventional Example 2), it was disclosed as a holographic element capable of controlling diffraction efficiency.

 In this example, as in Conventional Example 1, a two-flux interference of a mixture of a polymer material that cures at a specific wavelength and a liquid crystal material that does not cure at this specific wavelength is applied. It is fabricated by illuminating the manuscript and forming a polymer material in the high-intensity part of the interference manuscript and a region containing a large amount of the liquid crystal material in the low-intensity part of the interference manuscript.

 Although it is not switchable, it is a holographic element formed using light-induced phase separation by two-beam interference exposure, as disclosed in Japanese Patent Application No. 8-166628 (hereinafter referred to as a conventional example). 3), and a number of examples, including Japanese Patent Application Laid-Open No. 9-32 2459 (Japanese Patent Application No. 8-144253 / hereinafter abbreviated as Conventional Example 4). It has been disclosed.

Holographic devices fabricated using such a light-induced phase separation phenomenon are not limited to two-beam interference exposure. As disclosed on pages 86 to 87 (hereinafter abbreviated as Conventional Example 5), a mixture of an ultraviolet-curable resin and a liquid crystal material was mixed at an appropriate ratio, and then a conductive transparent electrode was formed. In some cases, the mixture is injected into a cell formed using a glass substrate, and then irradiated with ultraviolet rays through a photomask having a grating pattern.

 In each of the above examples, regions having different refractive indices are formed using light-induced phase separation, and this technique is described in, for example, Sharp Technical Report, No. 63, pp. 14--17, 1 As disclosed in December, 1995 (hereinafter abbreviated as Conventional Example 6), it is also used to fabricate a micro-open cell structure for widening the viewing angle of a liquid crystal panel. It is a known technique.

 In this example, a mixture of a photo-curable resin and a liquid crystal is illuminated with lattice-like light (wavelength is a wavelength that cures the photo-curable resin), and each light is induced by a photo-induced phase separation phenomenon. A microcell structure surrounding the pixels is formed. As a result, the liquid crystal molecules are aligned in the liquid crystal region in an axially symmetrical shape stabilized by the photo-curing reaction by the self-alignment force, thereby realizing a wide viewing angle and a high contrast.

Next, an example in which the present invention is applied to a knock-right unit of a direct-view type liquid crystal panel 19 will be described with reference to FIG. The direct-view type liquid crystal panel can be classified into a transmissive type and a reflective type. For example, as disclosed in Japanese Unexamined Patent Publication No. Hei 9-197949 (hereinafter abbreviated as Conventional Example 7), the image display device of FIG. 1 includes a cold-cathode tube (hereinafter referred to as a light source). , CCFT) Light from 23 enters from the end face of the light guide 21, and the hologram element 30 and the reflection mirror 23 formed on the back side of the light guide 21 are formed. The hologram element 30 is a reflection-type hologram. With the above configuration, the number of parts, weight, and cost are reduced, and at the same time, the backlight unit has high uniformity of brightness, high efficiency, and directivity. Can be used. This function is realized by making the hologram element 30 an aggregate of minute holograms. That is, the mosaic-shaped micro hologram is manufactured so as to exhibit the maximum diffraction efficiency at different incident wavelengths and incident angles.

 In a similar configuration, as disclosed in, for example, Japanese Patent Application Laid-Open No. 9-127894 (hereinafter abbreviated to Conventional Example 8), the area density of the reflective hologram is reduced. There is disclosed an example in which the higher the distance from the light source, the higher the brightness uniformity is realized.

 In addition to this, for example, processing 'obb', 'international' 'display' 'workshops', 97, 411 pages to 414 (hereinafter referred to as Conventional Example 9) ) Or as disclosed in Japanese Patent Application Laid-Open No. 9-138396 (hereinafter abbreviated to Conventional Example 10) as a reflection plate of a reflection type liquid crystal panel. An application is considered that selectively reflects an incident light beam in a direction substantially perpendicular to the liquid crystal substrate and substantially within a specific solid angle (diffraction), and displays a bright image with a narrow viewing angle. This hologram element is a so-called reflective volume hologram.

 In the conventional examples 7 to 10, the general photopolymer is used as the material, and the hologram element always performs the above-described reflection.

 Next, the image display device will be described.

In recent years, it has been difficult to increase the size of conventional direct-view TVs. Projection image display devices that enlarge and project the output image of the image display means that modulates the illuminating luminous flux from the luminance lamp are being developed (see, for example, O-Plus, August, 1993, 58 Page 1 101).

 FIG. 67 shows a configuration of a conventional general projection type image display device, and shows a configuration example using a liquid crystal panel as image display means. The output light 3 from the lamp 2 is reflected by the reflector 14, and the output light beam 5 is condensed and propagated by the condensing optical system (not shown), and the dichroic light is used for color separation. The liquid crystal panel is separated into the three primary colors of red, green and blue by the low-power mirrors 12 and 13, and the liquid crystal panel 16 passes through the total reflection mirror 14 and the capacitor lens 15. ~: Inject into L8. The output light modulated by the liquid crystal panels 16 to 18 is supplied to a dichroic prism (not shown) for color synthesis or a dichroic mirror 19, The image is synthesized by 20 and the total reflection mirror 14, and enlarged and projected on a screen (not shown) by the projection lens 9.

 The liquid crystal panels 16 to 18 are mainly classified into transmissive and reflective types, but in both cases, the incident light is input through a polarizing plate or a polarizing beam splitter (hereinafter abbreviated as PBS). An image is displayed by modulating the linearly polarized light of this with a liquid crystal material.

 The liquid crystal panels 16 to 18 are generally active mats in which thin-film transistors (hereinafter abbreviated as TFTs) are arranged in each pixel as switching elements for driving each pixel. The liquid crystal method is the mainstream, and the TFT is generally formed of polycrystalline silicon. Lamp 2 is required to have a high luminous efficiency, a small luminous body volume, a high luminosity, and a high color rendering property, such as a metal halide lamp, a xenon lamp, Ultra-high pressure mercury lamps are used.

As the reflector 4, it is easy to make effective use of the reflected light beam 5. For this reason, parabolic mirrors, elliptical mirrors, spherical mirrors, and the like are used, and the luminous body is often arranged at the focal point or first focal point or the center of the reflecting mirror. Currently, the mainstream is to use a parabolic mirror and install a light emitter near the focal point to obtain a substantially parallel light flux.

 In recent projection-type image display devices, when displaying an all-white signal,

 (1) Equalize the brightness of the central part and the peripheral part of the projected image.

 (2) Improve the projection efficiency (lumen / watt) defined as the value obtained by dividing the total luminous flux (lumen) projected by the lamp power consumption (bit).

 This is the main task of the development. For (1), the introduction of an integrator, and for (2), the integration of an integrator and a high-intensity lamp with a small luminous body. In addition, a solution by combining a polarization conversion element is being attempted.

 First, let's talk about the integration. Integre overnight means that minute lenses are two-dimensionally arranged as disclosed in, for example, JP-A-3-111806 and JP-A-5-346557. It is composed of two types of fly's eye lenses. Fig. 7 shows a specific example of the configuration of the integration. By means of the reflector 4 and the first fly-eye lens 49, the image of the illuminator of the lamp 2 is converted into a second fly corresponding to each lens of the first fly-eye lens 49. Eyes are imaged on each of the 50 lenses. Each of the lenses of the second fly-eye lens 50 is configured to form an image of the first fly-eye lens 49 on the image display means 7.

With the above configuration, each lens of the second fly-eye lens 50 is displayed as an image. The image formed on the means 7 is obtained by finely dividing the output light having a large luminance distribution outputted from the reflector 4 by each lens of the first fly-eye lens 49. The result is superimposed on the image display means 7. With this principle, it is possible to increase the brightness of the peripheral part relative to the central part of the projected image to 70% or more.

 Also, with the introduction of the integration, the projection efficiency can be improved. Generally, the light beam 5 reflected by the reflector 4 is substantially circular, but the image display means 7 is, for example, a 4: 3 rectangular shape. Therefore, when illuminating the image display means 7 in a circular shape, only the area ratio of the rectangle inscribed in the circle was effectively used. This is called a rectangular conversion efficiency. When the image display means 7 having a 4: 3 rectangle as the outer shape is used, the rectangular conversion efficiency was about 61%. However, the opening shape of the lens used for the first fly-eye lens 49 during the integration is shown in FIG. : By arranging as 3, it is possible to increase to about 80%. Next, the polarization conversion element will be described. The projection type image display device using the polarization display means such as the liquid crystal panel described above has a drawback that only the polarization component in a specific direction can be effectively used in the output light of the lamp. There were problems such as low projection efficiency and the need to use a light source with a large output to obtain a bright image. A polarization conversion element has been developed to solve this problem, and a polarization component absorbed by a polarizing plate or a polarization component that is not incident on a liquid crystal panel by PBS is applied to the polarization component. It effectively converts the light into a polarized light component having a generally orthogonal polarization plane.

Examples of the polarization conversion element include, for example, JP-A-5-107505, JP-A-6-22094, JP-A-7-294946, JP-A-8 Although many are disclosed, such as Japanese Patent Application Publication No. 24324/1995 and Japanese Patent Application Laid-Open No. 9-105593, they basically consist of a combination of a polarization separation element and a polarization plane rotation element. .

 FIG. 8 shows a configuration diagram of a general polarization conversion element 58. Non-polarized light (randomly polarized light flux) 62 is polarized by the polarization separation element 60 so that the polarization components are orthogonal to each other, that is, P-polarized light (parallel to the paper surface that is transmitted without being reflected by the polarization separation element). A light beam having a polarization direction 63 3, and an S-polarized light beam (a light beam having a polarization direction that is reflected by the polarization splitting means and having a polarization direction perpendicular to the paper surface) 64, and only the S-polarized light 64 is reflected by the reflecting means 60. (In general, a film of the same type as the polarization separation means 60 is used), and is converted into P-polarized light 6 3 ′ by the polarization plane rotation element 61.

 In recent years, it is often composed of a combination with a lens array 66, and the contents described in the above five publications can also be used in combination with the lens array 66. The configuration differs slightly depending on the installation position of the polarization separation element.

 In one method, the width of the light beam incident on the polarization conversion element 58 is reduced to approximately half by the lens array 66, and the light beam is incident only on the polarization separation element 60 to perform polarization separation and polarization plane rotation. (See Figure 9). In this case, by using the lens array 66 as the fly's eye lens constituting the integration, the uniformity of the brightness of the projected image is simultaneously secured as described above. Often do. That is, a configuration is considered in which the lens array is used as a second fly's eye lens of the integer.

On the other hand, as disclosed in Japanese Patent Application Laid-Open Nos. Hei 6-22094 and Hei 8-234205, polarized light is placed on the lamp side of the first fly-eye lens. A separation element is installed, and the exit angle of the light beam after polarization separation is adjusted according to the polarization component. A method has been devised in which the position of image formation on the second fly's eye lens is changed for each polarization component by changing the polarization by several degrees, and only one of the polarization components rotates the plane of polarization. As an application of this method, a configuration in which a polarization separation element is provided between the first fly-eye lens and the second fly-eye lens has been considered.

 In most cases, a conventional polarization conversion element uses a dielectric multilayer film formed by laminating a plurality of dielectric layers as a polarization separation element. A hologram element having polarization selectivity as a polarization splitting element is a conventionally known force; a hologram element is combined with an integer to constitute a polarization conversion element, and a projection type image display device is provided. There is no disclosure of an example applied to an illumination optical system.

 In the hologram element having polarization selectivity disclosed in Japanese Patent Application Laid-Open No. H8-23414, U.S. Pat. No. 5,161,039, a liquid crystal polymer or a nonlinear light is used. The use of a polysilane polymer material having an absorption effect has a polarization selectivity, and for each polarized light, it functions as a so-called volume hologram. Have.

 In addition, when using a projector, there is a high demand for a bright projection image that can be recognized even if the room is not too dark, so it is possible to improve the light use efficiency of the liquid crystal light knob. is important. Two lens plates were used as an optical system for improving the uniformity of the illuminated area in Japanese Patent Application Laid-Open Nos. Heisei 3-111 and Hei-5-346557. An integral optical system is disclosed.

This is in principle the same as that used in an exposure machine.A parallel light beam from a light source is divided by a plurality of rectangular lenses, and the image of each rectangular lens is divided into each rectangular lens. One-to-one corresponding relay lenses are used to superimpose and form images on liquid crystal lights and lubes. In addition, Japanese Patent Application Laid-Open No. Hei 6-202904 proposes an illumination optical system in which a polarization conversion method is combined with an integral illumination method. Figure 4 shows a schematic diagram of this. The light emitted from the light source 1101 enters a polarization splitting device using liquid crystal, and is separated into a P wave 1106 and three waves 111. These lights were arranged behind the second lens 1104 by the first lens group 1103 and the second lens group 1104, which constitute an integral unit. Different images are formed at different positions of the phase plate 1 105. In the phase plate 1105, a 1Z2 wave plate is periodically formed in approximately half the area of one lens forming the second lens group.

 For this reason, for example, the P-wave 1106 imaged at the position of the half-wave plate is emitted as an S-wave with the polarization direction rotated 90 °. The S-wave 107 is imaged in a region where the half-wave plate is not formed, and is transmitted as it is. In other words, the light waves emitted from the phase plate 1105 have substantially equal polarization directions.

 Japanese Patent Application Laid-Open No. 7-294006 discloses a polarization conversion element in which a lens plate and a prism are combined. Figure 5 shows the outline. This is because the light wave that has entered the lens plate 1201 on which the array-like lens has been formed has its luminous flux narrowed and enters the prism 122. Here, the S-wave 122 4 passes through as it is, and the P-wave 125 5 is reflected by the prism, enters the next prism, is reflected again, and changes its 90 ° angle. Then, it passes through a half-wave plate placed in the optical path, rotates the polarization direction by 90 °, and emits it as an S-wave. As described above, the light wave emitted from the combination of the lens plate 1201 and the prism 122 becomes a light beam with a uniform polarization direction.

Here, the image display principle of the liquid crystal element will be described with reference to FIG. Light sources such as fluorescent lamps and metal halide lamps The light emitted from is composed of a P-wave 92 having a polarization direction parallel to the paper surface and an S-wave having a polarization direction perpendicular to the paper surface. This light beam enters the polarizer 904, where a specific polarized component is absorbed and the remaining components are transmitted. The polarizer 904 is configured to absorb the S-wave component and transmit the P-wave. The light transmitted through the polarizer 904 is incident on the liquid crystal element 905.

 Here, as the liquid crystal element 905, a diagonal nematic liquid crystal in which the directions of liquid crystal molecules are twisted by 90 ° between the entrance surface and the exit surface will be described as an example. The liquid crystal element 905 is provided with a patterned transparent electrode, so that an electric field can be applied to each pixel. In the pixel (0N) to which the electric field is applied to switch the liquid crystal completely, the liquid crystal molecules are untwisted and the liquid crystal molecules stand isotropically with respect to the incident surface (home port). (Pic). Therefore, the P-wave incident on this pixel passes through the liquid crystal element without being modulated and maintaining its polarization state.

 Next, in the pixel (OFF) to which no electric field is applied, the angle of the liquid crystal molecules is twisted by 90 ° in the thickness direction from the entrance surface to the exit surface. Therefore, the P-wave component incident on this pixel rotates its polarization plane by 90 ° due to the twist nematic effect caused by twisting of the liquid crystal while passing from the entrance plane to the exit plane. . Therefore, after passing through the OFF pixel, the preceding light is emitted as an S wave.

After passing through the liquid crystal element, the polarization direction of light differs depending on the presence or absence of an electric field of the pixel corresponding to the passing position. Next, these lights are incident on the polarizer 906. Here, the polarizer 906 is set at an angle of 90 ° with respect to the previous polarizer 904 so that the axis passing through the polarization component is inclined by 90 °. One In addition, polarizers 904 and 906 are arranged in crossed Nicols. For this reason, of the light that has passed through the liquid crystal element, the P-wave is absorbed by the polarizer 906, and the S-wave passes through the polarizer 906.

 As described above, the light passing through each pixel of the liquid crystal element has its polarization direction modulated according to the electric field applied to the pixel, and as a result, the intensity of the light passing through the polarizer 906 differs. It will be. Since the amount of light passing through the polarizer 906 is different for the observer 907, the image as a bright and dark pattern corresponding to each pixel is recognized. become.

 In addition, by controlling the amount of electric field applied to each pixel, the polarization direction of light passing through the liquid crystal can be set to an intermediate state between the P-wave and S-wave states. Is also possible.

 Next, the optical information processing apparatus will be described.

 An optical information processing device that records and reads information stored in an optical storage medium such as an optical disk or a magneto-optical disk mainly uses a semiconductor laser as a light source and emits light from the semiconductor laser. Lens to focus the incoming light onto the optical storage medium, and a hologram element as a diffractive optical element to guide the laser light reflected on the optical storage medium to the light receiving element. You.

At one end, light emitted from the semiconductor laser passes through this holographic element and is focused by the imaging lens onto the surface of an optical disk as an optical storage medium. The light that is reflected at the surface of the optical disc and spreads at an intensity corresponding to the recorded information is converged by the lens again, partly returns to the semiconductor laser, and partly split into, for example, two regions. The hologram element is divided in two directions by the holographic element, and the image is formed on the light-receiving element divided into several areas. The image is defocused and trough using a technique such as the knife edge method. Without packing , And the detection of information signals.

 As described above, the light emitted from the laser passes through the hologram element as the diffractive optical element twice, on the outward path and the return path. If the light is diffracted strongly after passing through the hologram element on the outward path, the amount of light condensed on the surface of the optical disk will decrease, and sufficient light intensity will be obtained on the disk. This may hinder accurate detection of signal information. For this reason, a hologram element is usually required to have a function of different diffraction efficiencies between the forward path and the return path.

 Since a semiconductor laser as a light source has polarization characteristics, selectivity of diffraction efficiency depending on a polarization direction is often used. Specifically, the light emitted from the semiconductor laser is transmitted without any diffraction effect in the direction of polarization of the light emitted from the semiconductor laser, and thereafter, is 波長 wavelength in the optical path with the disk. A phase plate such as a plate is arranged, and the direction of polarization is set to rotate 90 ° compared to the initial direction when it is reflected by the disk and passes through the hologram again. At this time, the hologram element generates a diffraction function, and the light passing through the hologram element is guided to a light receiving element that detects information signals and the like.

 The hologram having such polarization selectivity is manufactured using an optical medium having refractive index anisotropy. For example, a mask is formed on a predetermined region of the surface of an optical medium having a refractive index anisotropy such as lithium niobate by photolithography or holographic exposure. Then, ion exchange is performed on the exposed area of the surface using benzoic acid or the like. Then, no refractive index distribution is generated for a specific polarization direction, and the object can be treated as a uniform object.

However, for light in the polarization direction orthogonal to the previous polarization direction, a refractive index distribution corresponding to the area formed by the mask is generated, and diffraction corresponding to this pattern is performed. A phenomenon will occur. Such features An optical information processing device is configured using a holographic element having a characteristic.

 All of the hologram elements disclosed in the above Conventional Examples 1 to 6 are optically substantially isotropic photocurable polymer materials that do not always have refractive index anisotropy; It is formed by a mixture with a liquid crystal material (hereinafter abbreviated as non-polymerizable liquid crystal) that does not cure at a wavelength that cures a photocurable polymer material, and forms a fine region. You. Therefore, for example, in Conventional Example 1, even if a voltage is applied to the area of only the non-polymerizable liquid crystal so as not to cause diffraction, for example, a hologram is obstructed with respect to the obliquely incident light flux. There was a disadvantage s that it would act as a system. This situation will be described with reference to FIGS.

 As shown in Fig. 2 (a), the conventional holographic element has a region 1 (with a refractive index of n1) made of a photocurable polymer material that is optically isotropic and a non-polymerizable material. It is formed by a liquid crystal region 2 (liquid crystal molecules have the refractive index anisotropy as shown in the figure, and the refractive indices for ordinary and extraordinary rays are no and ne, respectively).

 Here, n 1 and n o select almost equal materials. When a voltage is applied to the transparent conductive electrode 1 (hereinafter abbreviated as I T0) and the liquid crystal molecules in the region 2 are switched, the liquid crystal molecules are arranged substantially perpendicular to the glass substrate 2.

 In this case, the vertically incident light flux 3 is optically isotropic (area) to the P-polarized light (polarized light component parallel to the paper) and the S-polarized light (polarized light perpendicular to the paper). Since the refractive index of both 1 and 2 is almost n 0), the light beam 3 goes straight without being diffracted.

When no voltage is applied to region 2, as shown in Fig. 2 (b), the liquid crystal molecules are arranged almost parallel to glass substrate 2, and region 2 has a refractive index anisotropy. Occurs.

 As a result, for example, the refractive index for P-polarized light acts as a hologram element that alternates between ne and n1, whereas for the S-polarized light, all regions are almost Acts as an isotropic medium with a refractive index of no. Therefore, the P-polarized light 4 is diffracted in the incident light beam 3 and the S-polarized light 5 goes straight.

 However, as shown in Fig. 3 (a), for the light beam 3 'obliquely incident, a mode in which a voltage is applied to align the liquid crystal molecules vertically so that the incident light beam travels straight. In region 2, refractive index anisotropy occurs. In other words, it acts as an isotropic medium with a refractive index of no for ordinary rays (in this case, S-polarized light) and travels straight, but for extraordinary rays (in this case, P-polarized light), the region 2 The refractive index becomes ne (S), and the incident light is diffracted as a hologram. Therefore, for example, when it was used as an optical switch, there was a disadvantage that complete control could not be achieved except for normal incidence.

 Actually, even if the region 1 is formed by using a photocurable polymer material which does not originally have refractive index anisotropy, if formed between the glasses of a narrow gap, it may be slight due to stress and the like. Expresses refractive index anisotropy. However, the difference is small and essentially the above phenomenon appears.

 The slight refractive index anisotropy may be a problem. For example, in the case of Conventional Example 6, when displaying black, the grid portion becomes a discontinuous area, and when displaying a high-contrast image, it is particularly conspicuous and uniformity is reduced. The disadvantage was that it was lost.

The problems described in detail above always arise in systems that exhibit a phase separation by using a mixture of an optically isotropic optically curable polymer material and a liquid crystal material. It is. On the other hand, there has been reported an example of producing a liquid crystal polymer composite retardation film using a mixture of an ultraviolet curable liquid crystal, which has recently attracted particular attention as a photocurable liquid crystal, and several types of non-polymerizable liquid crystals. (Eg, '97 LCD Symposium Proceedings, pp. 168-169, pp. 1997). However, in the above example, the entire surface is simply and uniformly irradiated with UV light, and the entire surface is hardened uniformly. Also, as described later, there is no mention of the effect that diffraction does not occur even for oblique incident light expected by the configuration of the present invention.

 Also, for example, in Japanese Patent Application Laid-Open Nos. Hei 9-218130 and Heisei 9-288206, a photocurable liquid crystal is injected into a cell in which strip-shaped ITO is formed. Then, by applying a voltage, photo-curing is performed in a state where the orientation of the liquid crystal molecules is partially changed to form a diffraction element.

 However, in the above example, the formation was performed using an essentially homogeneous liquid crystal material, and no disclosure was made regarding the use of a mixture with a non-polymerizable liquid crystal. The refractive index anisotropy between different regions is equal, but is not switchable and is essentially different from the present invention.

 In addition, in the example applied to the direct-view type liquid crystal panel disclosed in Conventional Examples 7 to 10, the holographic element always realizes the above-described functions, and the holographic element is used as needed. No example of changing the function of the system element is disclosed.

 Also, in a conventional image display device, when a polarization splitting means is formed using a dielectric multilayer film, a plurality of thin-film dielectric layers are laminated, so that it takes a long time to manufacture and is costly. There were drawbacks.

In addition, Japanese Patent Application Laid-Open Nos. 7-294946 and 7-91 are formed by laminating a plurality of prisms and forming a dielectric multilayer film on a bonding surface. The polarized light separating element disclosed in Japanese Patent Application Laid-Open No. 10-59336 has problems in difficulty in manufacturing, high cost, heat resistance of the adhesive, and the like.

In Japanese Unexamined Patent Application Publication Nos. H05-107505 and H08-234250, a thick parallel plate or a right-angle prism is used, and a compact structure is required. It was difficult. In addition, in Japanese Patent Application Laid-Open No. 6-22094, it was difficult to form a saw-tooth shape. The polarization separating element using the dielectric multilayer film cormorants good above costs are rather high, making had gutter cormorants disadvantage force ^s is difficult.

 Further, a polarization splitting element using a hologram element having a polarization selectivity disclosed in Japanese Patent Application Laid-Open No. 8-234143 and US Pat. No. 5,161,039 is described above. As described above, no application example as a polarization conversion element combined with an integrator as an illumination optical system in a projection type image display device is disclosed. Even if a conventional hologram element is incorporated into a polarization conversion element as a polarization separation element and applied to a projection-type image display device, it is difficult to achieve high efficiency for the following reasons. there were.

 For example, consider a case in which a polarization splitting element is provided in front of the first fly's eye lens in the whole night. The light incident on the polarization separation element is a substantially parallel light flux. These light beams are, of course, unpolarized light. In this case, it is preferable that the difference between the emission angles of the two polarized light beams output from the polarization separation element after the polarization separation and whose polarization directions are orthogonal to each other is at most several degrees. This is because two images of the illuminator of the lamp are formed on each minute lens of the second fly-eye lens corresponding to each minute lens of the first fly-eye lens. You. If this angle difference is too large, the diameter of each lens of the second fly-eye lens must be increased.

That is, as a polarization splitting element, a substantially parallel light beam is After separation, each must be output with an angle difference of several degrees. This means that the difference between the incident angles of the reference light and the object light when fabricating the hologram element must be as small as several degrees at most. However, in order to increase the efficiency of the volume hologram sufficiently to be usable, the difference between the incident angles of the reference beam and the object beam is generally required to be at least 20 degrees or more. If the angle difference is smaller than that, the efficiency as a volume hologram decreases. Therefore, the first type of polarization conversion element could not be configured using a conventional hologram element as a polarization separation element.

 Examples of the diffractive element include an example using a normal nematic liquid crystal as disclosed in Japanese Patent Application Laid-Open No. 5-173196, a Japanese patent, and a journal. Examples of using UV-curable liquid crystal as disclosed in US Pat. Or, as disclosed in Chemical, Material, 1993, Vol. 5, pp. 1533–1538, using the polymer monodispersed liquid crystal. Although it is known, the one disclosed in the above publication discloses only that it has a polarization separation function, but does not disclose any application as a polarization conversion element. As described above, when a polarization conversion element combined with INTEGRA is configured using a polarization separation element formed by a conventional dielectric multilayer film and applied to a projection-type image display device, However, there were problems such as (1) high cost, (2) difficulty in fabrication, and (3) difficulty in compact construction.

In general, a hologram element is used in combination with (2) Integrate, because (1) the efficiency is low unless the difference between the incident angle and the output angle is increased. It was difficult to use as a polarization separation element. Furthermore, in the conventional diffraction element,

 1) It merely discloses that it has a polarization separation function,

2) It does not disclose any combination with Integre Ichigo and cannot be applied to a projection type image display device.

 In addition, a polarization separation element using liquid crystal has a configuration in which liquid crystal is sandwiched between a glass substrate and a prism substrate having a saw-shaped groove. Since liquid crystals exhibit refractive index anisotropy, the difference in the refractive index differs depending on the polarization direction, such as ordinary light and extraordinary light.

 The light wave incident on the polarization separation element generates a phase distribution corresponding to the sawtooth shape, and functions as a phase type diffraction grating. Furthermore, the refractive index difference when passing through the liquid crystal layer differs depending on the polarization direction. For this reason, the phase distribution differs depending on the polarization direction of the incident light wave, so that the ordinary light and the extraordinary light, that is, the directions diffracted by the P wave and the s wave are emitted in different directions. .

 In order to separate the P and S waves in the second lens array, a diffraction angle that is separable is required. For this reason, it is necessary to reduce the sawtooth pitch of the polarization separation element to about several tens of meters. At this time, it is necessary to uniformly and strictly design the sawtooth inclination. This is because the inclination of the sawtooth shape corresponds to the blaze angle of the diffraction element, and this shape and uniformity affect the efficiency of the diffracted wave. In other words, if the sawtooth-shaped groove deviates from the design, the problem arises that the diffracted wave is dispersed and the degree of separation by the polarization separation element is reduced.

Increasing the width of the sawtooth-shaped groove can increase the sawtooth-shaped pitch and facilitate machining. In this case, if the separation angle is maintained at the same level as in the original case, the liquid crystal cell gap needs to be thickened. However, it is necessary to align the liquid crystal uniformly in a thick cell gap. It is difficult to achieve this, and phenomena such as white turbidity occur, causing a new problem that the transmittance of the polarization separation element is reduced and the light use efficiency is reduced.

 In a polarization splitting element using a prism, the light beam is converged by a lens plate at one end, and is incident on the prism array every other row. Since the prism has the function of a polarizing beam splitter, for example, an S wave is transmitted and a P wave is reflected at a right angle, and further reflected at an adjacent prism at a right angle, and the light propagation direction is changed. It is equal to the preceding S wave. Thereafter, the polarization direction is rotated 90 ° by a half-wave plate placed in the optical path, and the light is emitted as a P-wave.

 Since the above-described operation is performed for each prism, the light wave incident on the lens plate can obtain a light beam having a uniform polarization direction without largely changing the width of the light beam. You. The prism is composed of a dielectric multilayer film and a liquid- or solid-filled cube for refractive index matching. In order to increase the degree of polarization separation, it is necessary to form a multi-layer dielectric multilayer film, which increases the manufacturing cost. The separation film is arranged at 45 ° to bend the light propagation direction by 90 °. For this reason, the size of the separation element in the thickness direction is fixed by the size of the separation film constituting one prism, and a problem arises in that the element cannot be made thin and small.

 The present invention solves the above-mentioned problems of the prior art, and provides a polarized light illuminating device having high light use efficiency using a diffractive optical element having excellent polarization selectivity and high diffraction efficiency as a polarization splitting element. An object of the present invention is to realize a projection display device capable of forming a bright projection image by combining a polarized light illumination device and a projection optical system.

In recent years, the use of monitors for power navigation and portable displays for personal viewing of video and image information has been increasing. Display, objects, It is positioned as a low power consumption type display for mobile information terminals such as mobile phones, which is called a tool. Common requirements for such displays include small size, light weight, thin shape, and low power consumption. In addition, in the case of a head-up display, there is a need to switch between the display screen and the outside world. At present, a display using a liquid crystal element can be considered as a display suitable for the above requirements. Liquid crystal displays have a smaller depth area and can be made thinner than displays like conventional CRTs. In addition, higher resolution has been achieved by reducing the pixel size, increasing the capacity, and introducing TFT devices, and the image quality has been further improved.

 However, the image display principle of a display using a liquid crystal element usually modulates the polarization direction of incident light according to the magnitude of an electric field applied to the liquid crystal element. By combining polarizers arranged in a cross nicol before and after the liquid crystal element, image information such as light and dark can be displayed using the difference in transmission of the polarizer depending on the polarization state of incident light. It is.

 In such a method, the light transmittance is not so high because the polarizer is an absorption type. Furthermore, since the polarizers are combined in crossed Nicols, the light transmittance is almost black in the state of only the combination of the polarizers. Therefore, it is difficult to obtain external information through the liquid crystal panel, together with image display, and it is not possible to use this type of head-up display. There is a problem that cannot be done.

In addition, since the polarizer is configured to transmit only a specific polarization component by absorbing light, the light absorbed by the polarizer is internally converted into heat. You. When the amount of incident light increases, the effect of heat generation inside the polarizer cannot be ignored, and problems such as a decrease in the light modulation function of the polarizer and deterioration of the element occur.

 Liquid crystal displays are not self-luminous devices like CRTs, so they require a dedicated light source for image display. Of the power consumption of the liquid crystal display, the ratio of the power used for this light source accounts for about half of the total, which is a barrier to reducing power consumption. For this reason, a method of displaying an image without using a dedicated light source for illumination is being studied. As a method for this, there is a reflection type image display device in which a liquid crystal element and a reflection plate are combined by using external light such as natural light or indoor illumination light as a light source. According to this configuration, since a dedicated light source is not required, power consumption can be reduced.

In the above method, the display state of an image changes depending on the state of external light used as illumination light. For example, it is difficult to view image information in a room where nighttime lighting is dark or where lighting cannot be used. For this reason, switching is performed in accordance with the location where the backlight as an internal light source and external light are used, environmental conditions, etc. to reduce power consumption and improve the convenience of viewing image information It is desirable to have a configuration that combines However, in order to utilize external light, it is appropriate to adopt a reflective configuration in which a single polarizer is placed on the entire surface of the liquid crystal element. It is suitable to use a transmissive structure in which polarizers are arranged in crossed Nicols before and after the element. In order to satisfy both of these methods simultaneously, it is conceivable to adopt a configuration using two polarizers. In projection image display, the brightness of the screen is significantly reduced, and the image quality is degraded. Therefore, it is difficult to use the internal light source and external light together. There is a problem.

 The present invention solves the above-mentioned problems of the prior art, configures an image display device by combining a diffractive optical element having excellent polarization selectivity and a high diffraction efficiency with a liquid crystal element, and is capable of performing a see-through type display. It is an object of the present invention to provide a low power consumption type image display device that can use a backlight, which is an internal light source, and external light in combination. Furthermore, by using the diffractive optical element as a transmissive type having a modulation in the refractive index distribution, the light use efficiency is improved, and at the same time as image display, versatile application as an illumination device for illumination light is realized. It is the aim.

 On the other hand, when a signal is detected from an optical storage medium using a polarization-selective hologram element manufactured by ion exchange or the like, the signal detection is large due to the diffraction efficiency of the hologram element. Affected. Specifically, the light is reflected by an optical disk or the like, is changed by a phase plate so that the polarization direction is orthogonal to the initial direction, and is incident on the hologram element.

 At this time, if the diffraction efficiency of the hologram element is low, the intensity of light reaching the light receiving element is weak and the noise increases, making it difficult to detect an accurate signal. Furthermore, since the component transmitted without being diffracted is irradiated to the semiconductor laser, which is the light source, instability of laser oscillation occurs due to an increase in the amount of light returning to the semiconductor laser, and noise in the light source itself is reduced. New issues such as occurrence will arise.

In order to solve this problem, it is necessary to improve the polarization selectivity and diffraction efficiency of the hologram element. Currently, there is a two-dimensional diffractive optical element type that can be used as a hologram element having polarization selectivity. This has a refractive index distribution that corresponds to the rectangular lattice shape, and generates a phase difference of 0 and 7 ° for each adjacent lattice with respect to the wavelength of the incident light. The light passing through this is a rectangular grid Diffraction occurs as a result of being strengthened in a specific direction corresponding to the distance between the two. In such a hologram element consisting of a rectangular grating, the diffraction wave is generated symmetrically because of the shape consisting of a two-dimensional binary. For this reason, there is a problem that even an ideal diffraction efficiency in which light is condensed in the primary direction having the highest diffraction intensity is limited to about 40%. Also, when the lattice shape deviates from the design value, the intensity ratio of diffracted to higher orders other than the first-order light intensity including the 0-order light intensity increases. Therefore, not only does the required first-order light intensity decrease, but the higher-order diffracted light acts as return light to the semiconductor laser, and the laser oscillation as described above is not affected. When it causes noise, it raises a problem of radiation.

 An object of the present invention is to provide a diffractive optical element used in an optical information processing device having excellent polarization selectivity and high diffraction efficiency, and a highly reliable manufacturing method of the element, which solves the above-mentioned problems of the prior art. And Disclosure of the invention

 The present invention has been made for the purpose of solving the above problems. A group of inventions for achieving this object is configured as follows.

 It has multiple regions with different material compositions,

 The plurality of regions are a first region made of a photocurable liquid crystal that is cured at least by a specific wavelength and has a refractive index anisotropy;

 Formed from a second region of non-cured liquid crystal (hereinafter abbreviated as non-polymerizable liquid crystal) by the wavelength,

The photocurable liquid crystal has a cured refractive index for ordinary light and a refractive index for extraordinary light after curing that are substantially equal to the refractive index for ordinary light and the refractive index for extraordinary light of the non-polymerizable liquid crystal, respectively. Hologram element.

 At least, it has polarization anisotropy with respect to the incident light beam,

 It consists of first and second holographic elements in the form of flat plates that selectively diffract only the first polarized light component.

 An angle Θ 0 between an optical axis and an incident light beam incident on the first hologram element;

 An angle S 1 formed by the first output light beam, which is obtained by diffracting the incident light beam by the first hologram element, with the optical axis,

 The angle O 2 formed by the second light flux, which is diffracted after the first output light flux is incident on the second hologram element and is output, is expressed by the following equation.

 1 ^ 1-0 2 I> 20

 I Θ 0-Θ 2 I <1 5

 A polarization splitting element characterized by satisfying the following.

 A light source, a diffractive optical element having refractive index anisotropy, and a total reflection mirror disposed adjacent to the light source, and

 A polarized light component (P wave or S wave) in one direction of the light emitted from the light source passes through the diffractive optical element, is reflected by the reflection mirror, and passes through the diffractive optical element again. Exits through

 A component (S-wave or P-wave) that is substantially orthogonal to the outgoing light changes its propagation direction due to the diffractive action of the diffractive optical element and emits the diffracted wave from the diffractive optical element. A predetermined wavefront of the diffractive optical element is formed such that the propagation directions of the reflected wave from the mirror and the total reflection mirror are substantially the same and the relative emission angles are different. Lighting device.

 Light source and

Equipped with patterned transparent conductive electrodes to form pixels A liquid crystal element having a liquid crystal layer sandwiched between two opposing transparent insulating substrates; and

 Diffractive optical elements arranged on both sides of the liquid crystal element

 Is configured to include at least

 Outgoing light from the light source is incident on one diffractive optical element and diffracted, and approximately 1/2 of the amount of light incident on the diffractive optical element is incident on the liquid crystal element.

 Modulated for each pixel of the liquid crystal element,

 An image display device, wherein an image is displayed by an action in which the propagation direction of light after passing through the other diffractive optical element differs according to the modulation degree.

 A laser emitting polarized light, an optical lens for converging a laser beam emitted from the laser on an optical storage medium, and a polarization direction of the laser beam reflected by the optical storage medium when emitted. A phase plate for rotating in a direction substantially perpendicular to the optical axis, a diffractive optical element arranged in an optical path of the reflected light to generate a predetermined wavefront, and a light receiving element for detecting light diffracted by the diffractive optical element What is claimed is: 1. A diffractive optical element used in an optical information processing device having at least an element as a constituent element, wherein the diffractive optical element is formed using an optical medium having a refractive index anisotropy. The predetermined wavefront is so determined that the ratio of the amount of light diffracted in the primary direction to the total amount of laser light after being reflected by the optical storage medium and transmitted through the diffractive optical element is approximately 1/2 or more. Is formed And a diffractive optical element.

A first and a second hologram element, which are arranged substantially in parallel with each other and selectively diffract a predetermined polarization component substantially equal to each other, A diffracted light beam that is incident on the first hologram element, diffracted by the first and second hologram elements, and emitted from the second hologram element;

 The angle formed by the transmitted light flux incident on the first hologram element, transmitted through the first and second hologram elements, and emitted from the second hologram element is 0 °. Exceeds and is less than 15 °,

 In the light flux incident on the first hologram element and diffracted by the first and second hologram elements, the light flux incident on each hologram element and the hologram element by the respective hologram element A polarization splitting element, wherein the angle formed by the diffracted light beam exceeds 20 °.

 A liquid crystal element that modulates the polarization direction of the incident light according to the applied voltage;

 A pair of first and second diffractions respectively disposed on both sides of the liquid crystal element for selectively diffracting a predetermined polarization component and transmitting a polarization component having a polarization direction orthogonal to the predetermined polarization component. An image display device comprising an optical element.

 A hologram element created by interfering an object light and a reference light, wherein the object light is a substantially parallel light flux (hereinafter, simply referred to as an object light flux), and the reference light is emitted from a light emitting unit. A luminous flux having a wavefront substantially equivalent to the luminous flux output from the illumination means for condensing and transmitting the first luminous flux

(Hereinafter, abbreviated as a reference light beam).

At least an image display means, and an illumination means for illuminating the image display means, wherein the image display means is incident on the image display means. An image is displayed by modulating and outputting the illumination light from the illumination means.The illumination means includes at least a light emission means, a first light collection means for collecting an output light flux of the light emission means, A first wavefront converting means for converting a wavefront of an output light beam of the first condensing means, wherein the first wavefront converting means is substantially equivalent to a wavefront of an output light beam of the first condensing means. An image display device comprising a first hologram element formed by drying a first light beam and a second light beam.

 A diffractive optical element comprising a plurality of minute regions, wherein the output light flux of the minute region is a light beam that generally overlaps on a plane that intersects at a predetermined angle with a normal direction of the diffractive optical element. A diffractive optical element characterized by: Brief explanation of drawings

FIG. 1 is a configuration diagram of a conventional projection type image display device.

Figure 2 shows the configuration of a conventional image display device.

FIG. 3 is a configuration diagram showing an integration used in a conventional projection type image display device.

FIG. 4 is a configuration diagram showing an integral view used in a conventional projection type image display device.

FIG. 5 is a configuration diagram of the image display device configured in the first embodiment. FIG. 6 is a diagram illustrating a method of illuminating a light beam for manufacturing a hologram element used for an image display device.

FIG. 7 is a diagram showing a method of illuminating a light beam for producing a hologram element used for an image display device.

FIG. 8 is a diagram showing a method of illuminating a light beam for manufacturing a hologram element used for an image display device. FIG. 9 is a principle diagram for generating an incident light beam for producing a hologram element used for an image display device.

FIG. 10 is a principle diagram for generating an incident light beam for producing a hologram element used for an image display device.

FIG. 11 is a configuration diagram of another image display device configured in the first embodiment.

FIG. 12 is a configuration diagram of another image display device configured in the first embodiment.

FIG. 13 is a configuration diagram of the image display device configured in the first embodiment. Figure 1 4 is Ru diagram der of another image display apparatus constituted in the first embodiment ₀

FIG. 15 is a configuration diagram of another image display device configured in the first embodiment.

Figure 1 6 is Ru diagram der of another image display apparatus constituted in the first embodiment ₀

FIG. 17 is a configuration diagram of another image display device configured in the second embodiment.

FIG. 18 is a configuration diagram of another image display device configured in the third embodiment.

FIG. 19 is a diagram showing a polarization conversion element used in another image display device.

FIG. 20 is a configuration diagram of the image display device according to the first embodiment.

FIG. 21 is a configuration diagram of an optical system for producing a hologram element. FIG. 22 is a configuration diagram of the image display device according to the second embodiment.

FIG. 23 is a configuration diagram of the image display device according to the third embodiment.

FIG. 24 is a configuration diagram of the image display device according to the fourth embodiment. FIG. 25 is a configuration diagram of the image display device according to the fifth embodiment.

FIG. 26 is a configuration diagram of the image display device configured in one embodiment. FIG. 27 is a plan view of the diffractive optical element.

FIG. 28 is a configuration diagram of another image display device configured in one embodiment.

FIG. 29 is a configuration diagram of another image display device configured in one embodiment.

FIG. 30 is a configuration diagram of another image display device configured in one embodiment.

FIG. 31 is a configuration diagram of another image display device configured in one embodiment.

FIG. 32 is a plan view of the diffractive optical element.

FIG. 33 is an explanatory view of a method for manufacturing a hologram element.

FIG. 34 is an explanatory view of another method of manufacturing a hologram element.

FIG. 35 is a configuration diagram of another image display device configured in one embodiment.

FIG. 36 is a configuration diagram of another image display device configured in one embodiment.

FIG. 37 is a configuration diagram of another image display device configured in one embodiment.

FIG. 38 is a configuration diagram of another image display device configured in one embodiment.

FIG. 39 is a configuration diagram of another image display device configured in one embodiment.

FIG. 40 (a) is a diagram showing the configuration of a holographic element, the arrangement of liquid crystal molecules, and the refractive index of each region according to an embodiment. FIG. 40 (b) is a diagram showing the configuration of the holographic element, the arrangement of liquid crystal molecules, and the refractive index of each region according to the embodiment.

FIG. 41 is a diagram showing a function of a hologram element configured in one embodiment for obliquely incident light beams and a refractive index of each region.

FIG. 42 (a) is a diagram showing the configuration of a holographic element, the arrangement of liquid crystal molecules, and the refractive index of each region according to another embodiment.

FIG. 42 (b) is a diagram showing the configuration of a holographic element, the arrangement of liquid crystal molecules, and the refractive index of each region according to another embodiment.

FIG. 43 is a configuration diagram of the polarization beam splitter configured in one embodiment. FIG. 44 is a plan view showing the alignment state of the liquid crystal in one process of the polarization beam splitter configured in one embodiment.

FIG. 45 is a schematic diagram showing the alignment state of the liquid crystal and the intensity distribution of the input interference image in one process of the polarization beam splitting device configured in one embodiment.

FIG. 46 is a schematic diagram showing the alignment state of the liquid crystal in the polarization beam splitter configured in one embodiment.

FIG. 47 is a diagram illustrating the efficiency of the polarization beam splitter configured in one embodiment.

FIG. 48 is a sectional view showing an example of the internal configuration of the diffractive optical element. FIG. 49 (a) shows an example of the angle and wavelength dependence of the diffractive optical element.

FIG. 49 (b) is a diagram showing an example of the angle and wavelength dependence of the diffractive optical element. FIG. 50 is a configuration diagram of an embodiment of a polarized light illumination device using a diffractive optical element. FIG. 51 is a configuration diagram of an embodiment of a polarized light illumination device using a diffractive optical element. FIG. 52 is a configuration diagram of an embodiment of a polarized light illumination device using a diffractive optical element.

FIG. 53 is a configuration diagram of an embodiment of a polarized light illumination device using a diffractive optical element.

FIG. 54 is a configuration diagram of an embodiment of a polarized light illumination device using a diffractive optical element.

FIG. 55 is a configuration diagram of an embodiment of a projection display device using a diffractive optical element.

FIG. 56 is a configuration diagram of an embodiment of a polarized light illumination device using a diffractive optical element.

FIG. 57 is a configuration diagram of an image display device using a hologram element. FIG. 58 (a) is a configuration diagram showing an embodiment of a projection type display device of a transmission type, one display type.

FIG. 58 (b) is a configuration diagram showing an embodiment of a transmissive color display type projection display device.

FIG. 59 (a) is a configuration diagram showing an embodiment of a projection type display device of a reflection type, one display type.

FIG. 59 (b) is a configuration diagram showing an embodiment of a projection type display device of a transmission type color display type.

FIG. 60 is a configuration diagram of an embodiment of an image display device using a diffractive optical element.

FIG. 61 is a configuration diagram of another embodiment of an image display device using a diffractive optical element. FIG. 62 is a configuration diagram of an embodiment of a reflection type image display device using a diffractive optical element.

FIG. 63 is a configuration diagram of an embodiment of a reflection type image display device using a back light using a diffractive optical element.

FIG. 64 is a configuration diagram of an embodiment of an image display device using a diffractive optical element.

FIG. 65 is a configuration diagram of an embodiment as an image display device and a lighting device using a diffractive optical element.

FIG. 66 is a configuration diagram of an embodiment of an image display device using a diffractive optical element.

FIG. 67 is a configuration diagram of one embodiment of a small-sized image display device using a diffractive optical element.

FIG. 68 (a) is a configuration diagram of an image display device having another configuration using a hologram element.

FIG. 68 (b) is a configuration diagram of an image display device having another configuration using a hologram element.

FIG. 69 (a) is a configuration diagram of a hologram element used in an image display device according to another embodiment.

FIG. 69 (b) is a configuration diagram of a hologram element used in an image display device according to another embodiment.

FIG. 70 is a configuration diagram of an embodiment of an optical information processing apparatus using a diffractive optical element.

FIG. 71 (a) is a diagram showing an example of refractive index modulation based on a refractive index ellipsoid of a uniaxial optical medium.

FIG. 71 (b) is a diagram showing an example of refractive index modulation based on a refractive index ellipsoid of a uniaxial optical medium. FIG. 72 is a diagram illustrating an optical system configured according to an embodiment of a method for manufacturing a diffractive optical element.

FIG. 73 is a diagram illustrating an optical system configured according to an embodiment of a method for manufacturing a diffractive optical element.

FIG. 74 is a configuration diagram of a conventional direct-view type liquid crystal display device.

FIG. 75 (a) is a diagram showing the configuration of a conventional optical switch and the refractive index of each region.

FIG. 75 (b) is a diagram showing the configuration of a conventional optical switch and the refractive index of each region.

FIG. 76 (a) shows the function of a conventional optical switch for oblique incident light and the refractive index of each region.

FIG. 76 (b) is a configuration diagram of a refractive index ellipsoid showing the refractive index anisotropy of a light beam obliquely incident.

Fig. 77 is a configuration diagram of a conventional polarization certifying device.

FIG. 78 is a configuration diagram of another conventional polarization certifying device. FIG. 79 is a configuration diagram of a conventional liquid crystal display device. BEST MODE FOR CARRYING OUT THE INVENTION

 The contents of the present invention will be specifically described based on examples.

 (Embodiment A1-1)

 An example of a so-called single-panel type image display device that displays a full-color image using a single image display element provided with a micro color filter will be described.

The image display device 101 is, as shown in FIG. 5, an illumination optical unit 104 composed of a lamp 102 and a reflector 103, and a diffractive optical element. The hologram element 105, the image display element 106, and the projection lens 107 are provided.

 As the lamp 102, for example, a metal halide lamp having a rated output of 400 Watts is used. The shape of the light-emitting region of this lamp 102 is almost cylindrical, and the length of the light-emitting region (arc) in the optical axis direction is about 4 mm. The lamp 102 is not limited to the metal halide lamp, but may be a nitrogen lamp, a xenon lamp, an ultra-high pressure mercury lamp, or the like.

 The reflector 103 is formed such that the reflection surface forms a paraboloid, and the lamp 102 has the center axis of the light emitting region substantially coincident with the optical axis of the paraboloid. It is arranged such that the focus of the paraboloid and the center of the light emitting area substantially coincide with each other. However, since the lamp 102 is not an ideal point light source and the light emitting region has a certain size, the reflected light beam P is not a light beam traveling strictly in parallel.

 The hologram element 105 converts the above-mentioned reflected light beam P into a parallel light beam (plane wave) Q almost parallel to be incident on the image display element 106. That is, when the reflected light beam P is incident as reference light, the parallel light beam Q is reproduced and output as object light. The hologram element 105 is formed by multiple exposure using, for example, three types of laser light of red, green, and blue wavelengths, and the details will be described later.

The image display element 106 controls a micro color filter in which an area for transmitting red, green, or blue light is formed for each pixel, and the amount of light transmitted for each pixel. A liquid crystal panel is provided, and the light transmitted through each pixel is subjected to luminance modulation, and the luminance-modulated light flux R is incident on the projection lens 107. The projection lens 107 enlarges and projects the incident light beam on a screen (not shown).

 As described above, the hologram element 105 converts the reflected light beam P from the reflector 103 into a parallel light beam Q, thereby causing a ramp 102 Even when the light source has a high output and a large light emitting area, the same luminous flux as when an ideal point light source is used can be obtained. Therefore, it is possible to obtain a projection image 1.2 times brighter, that is, a projection image 1.2 times brighter than the case where the hologram element 105 is not used.

 Next, the hologram element 105 and its manufacturing method will be described in detail.

 The hologram element 105 has a light flux as a reference light (hereinafter, referred to as “real light flux”) having a wavefront substantially equivalent to the reflected light flux P, and a wavefront substantially equivalent to the parallel light flux Q. It is manufactured by irradiating a hologram material such as a photopolymer with a light beam (hereinafter, referred to as an “ideal light beam”) as object light to form two-beam interference fringes. You. As a result, the hologram element 105 receives the reflected light beam P from the reflector 103 as reference light, thereby obtaining the object light as described above. As described above, it is possible to emit the parallel light flux Q almost in parallel. Here, the light beam and the wavefront will be briefly described. Generally, light can be described as the following (Equation 1) as a wave oscillating sinusoidally.

 [Equation 1]

u-A exp i (ωt — kr) where A is the complex amplitude, i is the imaginary unit, ω is the angular velocity, t is the time, k is the wave vector, and r is the position vector that determines the coordinates of the space. It is toll. The plane perpendicular to this wave vector is generally called the wavefront. A light beam is a collection of a plurality of light waves (light as waves). In an isotropic medium, a wave vector means the traveling direction of a light wave. The wavefront of a wave is defined as an aggregate of wavefronts of multiple light waves.

 For example, “a wavefront approximately equivalent to a reflected light beam P or a parallel light beam Q (real light beam or ideal light beam)” is a set of wavefronts that are approximately equal to the wavefronts of all light waves included in the reflected light beam P or the parallel light beam Q. The body is defined.

 Also, for example, "a light beam having a wavefront substantially equivalent to the reflected light beam P or the parallel light beam Q" is a set of light waves having a wavefront approximately equal to the wavefront of any light wave included in the reflected light beam P or the parallel light beam Q. The light flux that is the body. "

As shown in FIG. 6, the hologram element 105 has a coherent real beam S and an ideal beam T output from the real beam generating means 110 or the ideal beam generating means 111 as shown in FIG. And irradiate the hologram material 113 through the half mirror 111 from the same direction to generate interference fringes, thereby forming a transmissive hologram element. It is formed. Further, as shown in FIG. 7, the real beam S and the ideal beam T may be directly applied to the hologram material 113 without passing through the half mirror 111. . Further, as shown in FIG. 8, by irradiating the real light flux S and the ideal light flux T from both sides of the hologram material 113, a rip-man type hologram element is obtained. It may be formed as follows. In FIGS. 6 to 8, for convenience, the actual light beam generating means 110 has a lamp 102 and a reflex 110 3, and the ideal light beam generating means 111 has Although it is depicted as having a point light source 111 a and a reflector 111 lb, this is because the actual light beam generating means 110 is provided; Via Kuta 103 While outputting an actual light beam having a wavefront substantially equivalent to the reflected light beam P output as a result, the ideal light beam generating means 111 generates an ideal light beam having a wavefront substantially equivalent to the almost exactly parallel light beam Q. It indicates that it is configured to output.

 Examples of the hologram material 113 include salt emulsion (bleaching type), photorefractive crystals such as iron-doped lithium niobate, and bichromic acid. General holographic materials such as gelatin and photopolymers, and photoregisters that record interference fringes as changes in unevenness (these are based on calculations, not two-beam interference) In the case of fabrication by electron beam, it is formed by electron beam drawing, ion beam etching, embossing method, etc.), photo-stable blast, UV-curable liquid crystal, liquid crystal polymer and film. It is also possible to use a mixture of photo resists. As the actual light beam generating means 110 and the ideal light beam generating means 111, concretely, for example, the following three structures can be used. First, the outline of each configuration will be described.

 The first configuration of the actual luminous flux generating means 110 uses a simulated luminous body having the same shape as the luminous area of the lamp 102 of the image display device 101 and emitting a coherent luminous flux. The luminous flux from the simulated luminous body is reflected by the same reflector as the reflector 103 of the image display device 101 so as to become the actual luminous flux S.

 The second configuration is substantially equivalent to the actual light flux S reflected from the reflector 103 in the first configuration, without using a reflector or a simulated illuminant. The luminous flux such as the divergence angle is directly generated.

In the third configuration, a real light flux S (object light) generated by the first configuration or the second configuration and a predetermined light flux (reference light) are caused to interfere with each other to generate a mass. A terhologram is produced, and the master hologram is irradiated with the same light beam (reference light) as the above-mentioned predetermined light beam to reproduce the actual light beam S (object light). is there.

 The first configuration of the ideal luminous flux generating means 1 1 1 1 uses a simulated luminous body and a reflex as well as the first configuration of the real luminous flux generating means 1 1 1. However, as the simulated illuminant, the shape of the light-emitting region of the ideal lamp, that is, a small size simulating a point light source, is used, and as the reflector, It is preferable to use one with high accuracy o

 The second configuration directly generates the ideal luminous flux τ itself without using a reflector or a simulated illuminant as in the second configuration of the real luminous flux generating means 110. Things.

 The third configuration is similar to the third configuration of the actual luminous flux generating means 110, and is similar to the ideal luminous flux T (object light) generated by the above-described first configuration or the second configuration. A master hologram produced by interfering a predetermined light beam (reference light) with a master hologram is used.

 Hereinafter, specific configurations of the actual light beam generating means 110 and the ideal light beam generating means 111 will be described in detail.

As shown in FIG. 9, the first configuration of the actual luminous flux generating means 110 is such that, as shown in FIG. It is supported and arranged. As the reflector 121, a reflector having the same shape as the reflector 103 of the image display device 101 is used. Here, the shape of the reflectors 103 and 121 can be set irrespective of what kind of light flux is output from the hologram element 105. Wear. That is, in the image display device 101, the light beam actually output from the hologram element 105 is equivalent to the ideal light beam T. For example, by using elliptical mirrors for the reflectors 103 and 121, a parallel luminous flux equivalent to that obtained from a point light source and a parabolic mirror from the hologram element 105 is obtained. Output, or using parabolic mirrors for the reflectors 103 and 121, which is equivalent to that obtained from an ellipsoidal mirror or a spherical mirror from the hologram element 105. It is also possible to output a highly convergent light beam.

The shape and position of the simulated luminous body 122 are set in the same manner as the luminous area in the lamp 102 of the image display device 101. Specifically, for example, when the lamp 102 is a metal halide lamp as described above, it has a columnar shape, and its major axis substantially coincides with the optical axis of the reflector 122. It is arranged so that it does. When the lamp 102 is a xenon lamp, the lamp 102 is substantially spherical, and is disposed so as to be positioned on the optical axis of the central force s reflector 121. The simulated luminous body 122 is made of a material having light reflectivity, and reflects the laser light U incident from the opening 12 la of the reflector 121. The light is scattered in the light source 122 to generate a real light flux S. That is, it is difficult to form a luminous body that emits coherent light flux in the same shape as the luminous region of the lamp 102, but it is difficult to use the simulated luminous body 122 as described above. Accordingly, the actual light flux S can be easily obtained by generating the same light flux. As a specific material of the simulated luminous body 122, a metal material such as aluminum or stainless steel is used, or light is reflected on the surface of glass, ceramic, resin material, or the like. It is possible to use a metal thin film or the like having a property. Further, it is preferable that the surface of the simulated luminous body 122 has some scattering properties by mechanical or chemical processing. In addition, on the surface of the simulated luminous body 122, a quartz glass equivalent to a luminous tube of lamp 102 (a spherical casing made of quartz or the like) is used. A coating such as a lath may be applied.

 In order to irradiate the entire surface of the simulated luminous body 122 with the laser light U, the laser light U is scanned or the laser light U is irradiated from a plurality of openings 122 a in the reflector 122. Irradiation may be performed simultaneously or sequentially. Further, in the case of sequentially irradiating, the hologram material 113 may be subjected to multiple exposure. Further, in order to accurately perform the wavefront conversion on the light beam emitted from the inside of the light emitting region in the lamp 102, the light beam is smaller than the simulated light emitter 122. The hologram material 113 may be subjected to multiple exposure using several simulated luminous bodies having an outer shape. Thereby, the wavefront conversion efficiency can be further improved. In addition, among the light beams scattered by the simulated light emitter 122, light beams directly reaching the hologram material 113 without being reflected by the reflector 121 are also generated. Accordingly, it is possible to form the hologram element 105 which can effectively use the light beam directly emitted from the lamp 102 when the image display device 101 is used. . That is, since the luminous flux directly irradiated from the lamp 102 has a large divergence angle, the conventional image display device almost reaches the projection lens 107 via the image display element 106. However, according to the present invention, such a light beam is also effectively used, and the projection efficiency can be further increased. The laser beam U may be of any wavelength in the visible light region, but if the hologram material 113 is multiple-exposed by sequentially using wavelengths corresponding to the three primary colors, It is possible to perform wavefront conversion with higher efficiency.

The second configuration of the actual luminous flux generating means 110 is such that, for example, a reflector 103 is formed by changing a parabola represented by the following (Equation 2) as shown in FIG. Axle) In the case of a parabolic mirror rotated about an axis, for example, let the luminous flux diverging at an angle in the range of S1 to S2 through point A in the same figure be the actual luminous flux S It is the one that was adopted.

 [Equation 2]

^{z = x 2/2 p +} p / 2 is just, p is a positive constant.

That is, the light emitting region of the lamp 102 is cylindrical like a metal halide lamp, and the point C (p + Δz, 0) is centered on the focal point F (p, 0) of the paraboloid. When located between the point D and the point D (p-Δ z, 0), the luminous flux emitted from the focal point F toward the point A on the paraboloid is parallel to the z-axis from the point A (SO). The light beams emitted from points C and D travel in a direction that forms an angle Δ51 or Δ02 with S0. Therefore, for example, if the planar simulated light emitting surface 13 1 is arranged on a plane perpendicular to the z axis including the X axis, the laser light emitted from the surface side of the simulated light emitting surface 13 1 The surface shape of the simulated light emitting surface 13 1 is formed so that the reflected light of the laser light or the transmitted light of the laser light emitted from the back surface travels in the directions of S 0, S l, S 2, etc. Thus, the actual light flux S can be obtained. More specifically, for example, an electron beam exposure or a sheet-like resin material, a metal material, a plastic material, or a photoresist layer formed on the surface thereof is used. By forming irregularities such as a saw blade shape or a step shape by embossing, ion beam etching, or the like, it is possible to form the above-described simulated light emitting surface 13 1. The hologram material 113 is exposed to the actual light flux S obtained by irradiating the simulated light emitting surface 131 with a laser beam and reflecting or transmitting the hologram material. Gram element 105 can be formed. As described above, the third configuration of the actual light beam generating means 110 is, as described above, a two-beam interference between the real light beam S generated by the first configuration or the second configuration and a predetermined light beam. The stripes are recorded on a hologram material to produce a master hologram, and the master hologram is irradiated with the same light beam as the above-mentioned predetermined light beam to reproduce the actual light beam S. It was done. By using such a master hologram, it is possible to expose the holographic element 105 to a single exposure as in the case of performing the multiple exposure by the first configuration or the second configuration. It can be manufactured by As the material of the master hologram, various materials as described for the hologram material 113 of the hologram element 105 can be used.

 The first configuration of the ideal luminous flux generating means 111 uses a simulated luminous body and a reflector similarly to the first configuration of the real luminous flux generating means 110, but the simulated luminous As described above, a small body that simulates a point light source is used as a body, and a reflector that is used in an actual image display device 101 is used as a reflector. Regardless of the shape and accuracy of O3, a different point is that a reflector having a shape and accuracy that can obtain a desired ideal light beam is used. That is, when a parallel light beam is obtained as an ideal light beam, a parabolic mirror may be used and the simulated illuminant may be arranged at the focal point of the paraboloid. In order to obtain a light beam condensed at a predetermined point, an elliptical mirror is used to arrange the simulated illuminant at one focal point, or a spherical mirror is used to arrange the simulated illuminant at the center of the spherical surface. do it.

The second configuration of the ideal luminous flux generating means 1 1 1 is to directly generate the ideal luminous flux T itself without using a reflex or a simulated illuminant as described above. For example, a laser beam is expanded by a refraction optical system to generate a parallel light beam, a convergent light beam, a divergent light beam, and the like, which are almost plane waves. The third configuration of the ideal luminous flux generating means 1 1 1 is a hologram that combines two luminous flux stripes of the ideal luminous flux T generated by the first configuration or the second configuration and a predetermined luminous flux. A master hologram is recorded on a master material, and the master hologram is irradiated with the same light beam as the above-mentioned predetermined light beam to reproduce the ideal light beam T. .

 (Embodiment A 1-2)

 Another example of the image display device will be described. In the following description, components having the same functions as those of Embodiment A1-1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

 The hologram element 105 is not limited to the one that outputs the parallel light flux Q as described above, and is imaged on the entrance pupil of the projection lens 107 as shown in FIG. 11. The convergent light beam Q1 may be output. Such a hologram element 105 can be manufactured by generating a light beam converging toward a predetermined point by the ideal light beam generating means 111. .

 By using the hologram element 105 that outputs the convergent light beam Q1 as described above, the projection efficiency is further improved, and compared with the case where the hologram element 105 is not used. Therefore, a 1.5 times brighter projected image can be displayed.

 (Embodiment A 1 — 3)

Instead of the parabolic mirror reflector 103 as described above, a spherical mirror reflector 141 and a focusing lens 144 are used as shown in Fig. 12. And may be used. In this case, the hologram element 105 generates the same light beam as the light beam output from the converging lens 142 by the real light beam generation means 110, and the ideal light beam generation means. By producing a parallel light beam by 1 1 1, it is possible to produce A parallel light beam Q 2 similar to that of form A l — 1 can be output. As in Embodiment A1-2, the hologram element 105 is manufactured by generating a light beam converging toward a predetermined point by the ideal light beam generating means 111. Alternatively, a convergent light beam focused on the entrance pupil of the projection lens 107 may be output.

 (Embodiment A 1 — 4)

 Further, as shown in FIG. 13, a reflector 144 of an ellipsoidal mirror may be used. In this case, by arranging the lamp 102 near one focal point of the elliptical surface, the reflected light from the reflector 144 can be condensed near the other focal point. Becomes However, since the light emitting area of the lamp 102 has a certain size, the reflected light from the reflector 144 does not accurately converge on the other focal point. Even if the luminous flux is high, the hologram element 105 produced by generating a luminous flux converging toward a predetermined point by the ideal luminous flux generating means 111 is used. As in the case of Embodiment A1-2, it is possible to obtain a convergent light flux Q3 formed on the entrance pupil of the projection lens 107. In addition, in the case of using the ellipsoidal mirror reflector 144 as described above, the ideal beam generating means 111 generates a parallel light beam using a holo- dram element. However, a parallel light beam similar to that in the embodiment A11 may be output.

 (Embodiment A 1 — 5)

 The so-called three-panel system, in which light from the light source is separated into light of the three primary colors of red, green, and blue, and a full color image is displayed using three transmissive image display elements corresponding to the light of each color An example of the image display device will be described.

As shown in FIG. 14, the image display device 15 1 includes an illumination optical system including a lamp 102 and a reflector 103 as in the embodiment A 1-1. A section 104 and a hologram element 105 are provided, and a parallel light beam Q is output from the hologram element 105. The parallel light beam Q is separated into three primary color light beams of red, green and blue by the dichroic mirrors 152 and 153, and the total reflection mirror 154 and the condenser After entering the LCD panels 156 to 158 corresponding to the red, green, and blue pixels via the lens 155, and performing luminance modulation, the total reflection mirror 159 and the dice It is synthesized by a color synthesizing system composed of mouth mirrors 160 and 161, and is enlarged and projected on a screen (not shown) by a projection lens 107. .

 In the three-panel image display device 151 as described above, the optical path length is longer than in the single-panel system. For this reason, in the conventional image display device, the loss due to the divergence of the light beam tends to increase, but almost completeness is obtained by using the hologram element 105 as described above. Obtains a bright projected image because a high parallel light flux Q is obtained.o

 (Embodiment A 1 — 6)

 An example of a three-plate type image display device using a reflection type image display element will be described.

As shown in FIG. 15, the image display device 17 1 includes an illumination optical unit 10 composed of a lamp 10 2 and a reflector 10 3, as in the embodiment A 11. 4 and a hologram element 105 are provided so that the parallel luminous flux Q is output from the hologram element 105. The parallel light beam Q enters the PBS (polarized beam splitter) 173 via the total reflection mirror 172, and the random polarized light beam is converted into an almost linearly polarized light beam. It has become so. The luminous flux converted to almost linearly polarized light passes through a lens 174 to a dichroic mirror 175, 176. Therefore, the light is separated into light beams of three primary colors, is incident on the reflection type liquid crystal display elements 177 to 179, and is subjected to luminance modulation. The projection lens 107 expands and projects the image on a screen (not shown). Incidentally, three PBSs may be used.

 In the reflection type three-panel type image display device 171 as described above, the optical path length is longer than that of the single-panel type, but the projection efficiency of the conventional image display device is, for example, 1 unit. On the other hand, while the image display device 171 using the hologram element 105 has a high projection efficiency of 1.8 lumens / unit, it is possible to obtain a high projection efficiency of 1.8 lumens / unit. I can do it.

 (Embodiment A 1 — 7)

 An example of an image display device provided with a hologram element and an integral view will be described.

 As shown in FIG. 16, the image display device 18 1 is provided with a hologram element 105 in the same manner as in the embodiment A 11 and the hologram element 1 is provided. Between the pixel 5 and the image display element 106, there is provided an integrator 184 comprising a first fly-eye lens 182 and a second fly-eye lens 183. Have been.

The first fly's eye lens 182 and the second fly's eye lens 183 each have a small lens group. That is, each minute lens of the first fly-eye lens 1882 is an image of the light-emitting area (light-emitting body) on the corresponding minute lens of the second fly-eye lens 1883. The image is formed. Also, each minute lens of the second fly-eye lens 183 is provided with an image of each minute lens of the first fly-eye lens 182 on the entire surface of the image display element 106. The images are superimposed to form an image. As a result, the light is output from the illumination optical unit 104. By dividing the light beam into a plurality of light beams and superimposing them on the image display element 106, unevenness in the amount of light at the center and the periphery of the display image can be reduced.

 The hologram element 105 generates a light beam having a wavefront substantially equivalent to the reflected light beam P output from the illumination optical unit 104 by the real light beam generation means 110. In particular, it is produced by generating a parallel light beam by the ideal light beam generating means 111.

 Here, the hologram element 105 actually manufactured may have chromatic aberration and magnification aberration, and the parallel light beam output from the hologram element 105 may be generated. Q is not always a perfectly ideal collimated beam, and the conversion efficiency is not always 100%. That is, most of the reflected light beam P output from the illumination optical unit 104 is converted into an ideal parallel light beam, but a part of the light beam is directly included in the parallel light beam Q. There is. Therefore, as described above, the hologram element 105 is combined with an integrator 184 similar to that used in a conventional image display device having no hologram element 105. As a result, a light beam that has not been converted into a parallel light beam can be effectively used, and the aberration of the hologram element 105 and the wavefront conversion loss can be compensated.

 Therefore, without providing the hologram element 105, it is possible to obtain a projection efficiency 1.4 times higher than in the case of the conventional image display apparatus provided with only the integrator 184. it can. Also, the peripheral light intensity ratio (the ratio of the brightness of the center of the screen to the brightness of the peripheral portion when displaying with an all-white signal) can be as high as 70% or more, which is the same as before. O

(Embodiment A 1 — 8) An example in which a reflective deflecting element as disclosed in US Pat. No. 5,096,279, for example, is used as an image display element will be described.

 As shown in FIG. 17, the image display device 191 includes an illumination optical unit 104 composed of a lamp 102 and a reflector 103, and an embodiment A 117. An integral unit 1884 similar to the above, an image display device 192 which is a reflective deflecting device, and a projection lens 107 are provided. In addition, while a hologram element 1 5 is provided between the first fly-eye lens 182 of the integration lens 1884 and the second fly-eye lens 183, the integration is performed. Between the evening 184 and the image display element 192, there is provided a lens 193 that converts the light beam outputted from the integration-evening 184 into a parallel luminous flux.

 As the lamp 102, a 400-watt metalno or Ride lamp is used, and a parabolic mirror is used for the reflector 103. . The shape of the light emitting area of the lamp 102 is almost cylindrical, and the length of the light emitting area (arc) in the optical axis direction is about 4 mm. This lamp 102 is such that the light-emitting area is located near the focal point of the reflector 103, and the central axis of the light-emitting area almost coincides with the optical axis of the reflector 103. Are located in The hologram element 105 is output from the illumination optics section 104 by the actual light beam generating means 110, and has a wavefront substantially equivalent to the light beam passing through the first fly-eye lens 1802. In addition to generating a light beam having the following formula, the ideal light beam generating means 111 converts the parallel light beam into a light beam passing through the first fly-eye lens 182 or a light beam equivalent thereto. It is made by making it work.

The lens 193 converts the light beam superimposed on the incident surface of the lens 193 by each minute lens of the second fly-eye lens 183 into a parallel light beam. 2 The image display element 192 performs display by changing the reflection angle of incident light for each pixel and changing the amount of light incident on the projection lens 107.

 With the above-described configuration, the luminous flux output from the first fly-eye lens 1822 can be accurately converted by the holographic element 105 into the second fly-eye lens. Is converted into a light beam incident on each minute lens (effective area) of lens 18 3. That is, when the hologram element 105 is not provided, the second fly's eye level is caused by the fact that the light emitting area of the lamp 102 has a certain size. In contrast to the fact that a luminous flux that does not enter each minute lens of the lens 183 tends to be generated, the provision of the hologram element 105 allows an accurate parallel luminous flux (plane wave) to be produced. The light is converted into a light beam having a wavefront almost equivalent to that through the first fly's eye lens 182, and surely enters each minute lens of the second fly's eye lens 183. In other words, almost all the light beams emitted from the lamp 102 can be made incident on the effective area of the second fly-eye lens 183, thereby reducing the light amount loss and improving the light use efficiency. It can be done. Specifically, for example, when an image display element for displaying a monochromic image having no microphone opening color filter is used, the projection efficiency is 4 lumen / ヮ in the conventional configuration. On the other hand, when the hologram element 1 ◦ 5 is used as described above, a projection efficiency of 8 lumens can be obtained.

 (Embodiment A 1 — 8)

 An example of an image display device in which the configuration of Embodiment A 1-7 is further provided with a polarization conversion element 202 will be described.

As shown in FIG. 18, this image display device has a structure in which the second fly-eye lens constituting the integration lens 1884 is connected to the liquid crystal display element 106. In addition, a polarization conversion element 202 and a condenser lens 203 are provided. As the image display element 106, for example, a transmissive liquid crystal panel is used, and as a lamp 102, an ultrahigh-pressure mercury lamp of 100 W and a reflector 103 are used. A parabolic mirror is used.

 For example, as shown in FIG. 19, the polarization conversion element 202 has a plurality of prisms 204 to which a pair of triangular prisms are joined, and is further joined in a flat plate shape. In addition, a polarization plane rotating means 205 is provided for every other prism 204. A polarization splitting film 206 is formed on the junction surface of the triangular prism. The polarized light separating film 206 is composed of, for example, a dielectric multilayer film, and transmits incident non-polarized light, for example, P-polarized light (polarized light whose polarization direction is parallel to the plane of the drawing). It is designed to reflect polarized light (polarized light whose polarization direction is perpendicular to the paper in the figure). The polarization plane rotating means 205 has a function of rotating the plane of polarization of the incident light beam by about 90 °, and generally has an optical anisotropy whose phase difference is about half of the incident wavelength. It is composed of materials.

In the polarization conversion element 202, the prisms 204, which are not provided with the polarization plane rotating means 205, are each a lens constituting a second fly's eye lens 183 of the integrator 184. The beams converged by the first fly's eye lens 49 by the first fly's eye lens 49 correspond to the second fly's eye lens. The light is incident on the corresponding prism 204. In the light beam incident on the prism 204, only the P-polarized light passes through the polarization separation film 206 and exits, while the S-polarized light is reflected by the polarization separation film 206 and the adjacent prism After being reflected by the polarization splitting film 204 of 204, it is converted into P-polarized light by the polarization plane rotating means 205 and output. That is, the polarization conversion element 2 0 2 From this, a light beam in which the unpolarized light from the lamp 102 is aligned with the P-polarized light is emitted.

 Here, the first fly-eye lens 182 is a prism that is not provided with the above-mentioned polarization plane rotation means 205 through the second fly-eye lens 183 via the second fly-eye lens 183. Although it is necessary to condense the light onto the body 204, the provision of the hologram element 105 allows the first fly even when the light emitting area of the lamp 102 is large. Since the focusing lens can reliably collect light as described above, the effect of improving the projection efficiency by the polarization conversion element 202 can be further enhanced to display a bright image. It's out.

In other words, in a conventional image display device, for example, even if a lamp having a light output area of 100 mm and a light emitting area of 1.45 mm is used as the lamp 102, the polarization is small. When a high-power lamp with a light-emitting area as large as several millimeters is used, the polarization conversion element 2 becomes only about 1.5 times brighter than the case without the conversion element 202. The degree of increase in the projection efficiency depending on the presence or absence of O 2 was further reduced, and was at most about 1.2 times brighter. On the other hand, since the hologram element 105 is provided as described above, the wavefront of the light beam passing through the hologram element 105 as described above is changed. Since the light is almost a plane wave, most of the luminous flux can be made to enter only the predetermined prism 204 through the second fly-eye lens 183. For example, it is possible to make it 1.8 times brighter than the case where it is not provided. In addition, even when a large emission area such as a 400-watt metal node lamp or a 2-kilobyte xenon lamp is used, the output from the hologram element 105 can be obtained. Since the wavefront of the luminous flux is almost equal to the wavefront of the luminous flux when a point light source is used, a polarization conversion element 202 is provided. As a result, the effect of greatly improving the projection efficiency can be obtained. Specifically, even when the above-described xenon lamp is used, the projection efficiency can be increased to 5 lumens / unit, and an image display device with a high light output of 10,000 lumens can be obtained. Could be constructed.

 The same effect can be obtained by using various polarization conversion elements or disposing the polarization conversion elements at other positions. For example, Japanese Patent Application Laid-Open No. H8-234420 and Japanese Patent Application Laid-Open No. H6-20010 dispose a polarization conversion element 202 on the lamp 102 side of the first fly-eye lens 102. A similar effect can be obtained when the polarization conversion element disclosed in FIG.

 (Embodiment A 2 — 1)

 An example of an image display device provided with a reflective hologram element that converts a light beam output from an integrated device into a parallel light beam will be described.

As shown in FIG. 20, the image display device 211 includes an illumination optical unit 1 composed of a lamp 102 and a reflector 103 similarly to the embodiment A 11 and the like. 0 4 and an integer 2 15 consisting of a first fly-eye lens 2 12, a second fly-eye lens 2 13, and a folded mirror 2 14 It is provided. The above-mentioned integration 215 has the same function as the integration 184 of embodiment A1-7, and the uniformity of the brightness of the projected image is ensured. I have. The luminous flux output from the integration device 215 is separated into three primary color luminous fluxes by dichroic mirrors 152, 153, and a reflection-type hologram described in detail later. After entering the LCD panel 2 19-2 21 corresponding to the red, green, and blue pixels via the ram elements 2 16 to 2 18 and being subjected to luminance modulation, the die cycle The colors are synthesized by mirrors 160 and 161 and enlarged and projected on a screen (not shown) by a projection lens 107. The image display elements 219 to 221 include a micro lens in which a minute lens is formed corresponding to each pixel, and a liquid crystal panel that controls the amount of light transmitted through each pixel. The light incident on the micro lens is focused on the effective area of the liquid crystal panel.

 The hologram elements 2 16 to 2 18 convert the light beam incident from the integrator 2 15 through the dichroic mirrors 15 2 and 15 3 into a parallel light beam. And output to the image display elements 219 to 221. Therefore, the luminous flux incident on the micro lens is surely condensed on the effective area of the liquid crystal panel, and almost all of the incident light is used, thereby substantially increasing the substantial aperture ratio. Projection efficiency and brightness uniformity of the projected image can be improved.

Specifically, for example, a liquid crystal panel with a diagonal dimension of 1.3 inches and a pixel of 1024 x 768 with an aperture ratio of about 56%, and an ultrahigh-pressure mercury of 100 W When the lamp is used, the projection efficiency is 5 lumen / unit when neither the micro lens nor the hologram element 2 16 to 2 18 is used, and the micro lens is used. In contrast to the projection efficiency of 6 lumens / unit when only the hologram element was used, the hologram elements 2 16 to 2 18 were additionally provided as described above. As a result, a high projection efficiency of 8 lumens / unit was obtained. This corresponds to an increase in the effective aperture ratio from 56% to about 90%. In addition, a liquid crystal panel having the same size and a large number of pixels, for example, a pixel of 128 × 10 24 pixels or more (eg, 1920 × 1080 pixels) is used. However, the projection efficiency was almost unchanged. Furthermore, by providing a polarization conversion element having a polarization separation unit and a polarization plane rotation unit in the illumination optical system, it is possible to realize an extremely high projection efficiency of 12 lumens / unit. Was. The hologram elements 2 16 to 2 18 as described above can be manufactured in the same manner as the hologram element 105 of the embodiment A-11. That is, a light beam having a wavefront equivalent to the light beam incident on the hologram elements 2 16 to 2 18 in the actual image display device 211 as the reference light, and a light beam as the object light The two light beam fringes, a parallel light beam to be incident on the image display elements 219 to 221 and a light beam having an equivalent wavefront, are recorded on a hologram material such as a photopolymer. It is made by doing.

Specifically, for example, when fabricating a hologram element 2 17 for green, as shown in FIG. 21, an integrator 2 15 and a die mirror mirror 1 2 5 , 153 and the hologram material 217 ′ are arranged so that an optical path similar to that of the actual image display device 211 is formed, and the laser light output from the laser 231 is used as a beam. After the beam width is widened by the beam ex- cember 23, the beam is split into two light beams V and W by the beam splitter 23, and the light beam V is turned back through the mirror 23 4 Then, the light beam W is directly incident on the hologram material 2 17 ′ while being incident on the integrator 215. Here, the wavelength of the laser light is that included in the wavelength band of each of the three primary colors incident on the hologram element in the actual image display device 211 (in this case, green). Desirably, in this case, the effect of chromatic dispersion on the diffraction efficiency of the hologram element can be minimized, and the diffraction efficiency of the hologram element can be increased. As a result, two light beam interference fringes of a light beam and a plane wave having a wavefront equivalent to the wavefront of the light beam incident at the position where the hologram element 2 17 is actually arranged are formed, and the image display device 2 When the luminous flux after color separation by the dichroic mirror 15 of 1 11 enters, it is converted into a parallel luminous flux and output to the image display element 2 20 holographic element 2 17 Is obtained. When an actual image display device is provided with a condenser lens, a relay lens, a deflection conversion element, and the like, these elements may be arranged in the optical path of the light beam V.

 Further, in addition to the above, the hologram element 2 16-2 18 can be manufactured by various configurations as described in the embodiment A1-1.

 As described above, the image display device of the present invention allows an illumination light beam after color separation to be input to the image display device via the holographic device 2 16-2 18 according to the present invention. Therefore, it is characterized by improving the projection efficiency.

 The same effects as those of the image display device having the configuration shown in FIG. 1 can be obtained irrespective of the type of light modulation material of the image display element, the light modulation method, the material for forming the drive element, and the drive method.

 Also, the configuration of the optical system is not limited to the above configuration, and various modifications are possible in accordance with the gist of the present invention.

 (Embodiment A2-2)

 An example in which the dichroic prism is used to synthesize the luminance-modulated luminous flux of each color will be described.

 As shown in FIG. 22, this image display device 2 31 is different from the image display device 2 1 1 of the embodiment A 2-1 in that the die-cloth mirrors 160, 16 1 In which a dichroic prism 235 is provided in place of a mirror, and that the optical path is configured to be different depending on the folded mirrors 232-234. Are different.

That is, when a white light beam enters the dichroic mirror 152 from the lamp 102 via the integrator 21, the red light component of the incident light beam is emitted. Is reflected, and the green and blue light beams are transmitted. Red The color luminous flux enters the reflection type hologram element 216 via the mirrors 233 and 234, and is converted into a substantially parallel luminous flux. The light enters the image display element (liquid crystal panel) 219 that displays the components, and the luminance is modulated. Further, the green light beam and the blue light beam transmitted through the dichroic mirror 1502 are returned to the dichroic mirror 1553 via the turning mirror 2332. The incident light reflects the green light and transmits only the blue light. The green light beam and the blue light beam are converted into substantially parallel light beams when they are reflected by the reflective hologram elements 211 and 218, respectively, and the image display for displaying each color component of the display image is performed. Light enters the element (liquid crystal panel) 220 and 221 and is modulated in luminance. The luminous flux of each color whose luminance has been modulated is synthesized by the dichroic prism 235, and enlarged and projected by a projection lens 107 on a screen (not shown).

 In the image display device 231 as described above, similarly to the embodiment A2-1, the output light beam from the lamp 102 is transmitted in parallel through the integrator 215 and the like. Is converted into a substantially parallel light beam by the hologram elements 211 to 218, then enters the image display elements 219 to 221 and is transmitted by the micro lens. As a result, light can be made to enter only the aperture of each pixel in the liquid crystal panel, so that the effective aperture ratio can be extremely increased.

Specifically, for example, a liquid crystal panel with a diagonal size of 0.9 inches and a pixel of 1024 x 768 with an aperture ratio of about 40%, and an ultrahigh-pressure mercury of 100 W When the lamp is used, the projection efficiency when neither the micro lens nor the hologram element 2 16 to 2 18 is used is 3.6 lumens / unit. The projection efficiency was 4.3 lumens / unit when only the chrome lens was used, whereas the holographic efficiency was increased as described above. By providing the hologram elements 216 to 218, a high projection efficiency of 8 lumens / unit could be obtained. This corresponds to an increase in the effective aperture ratio from 40% to about 90%. In addition, a liquid crystal panel having the same size and a large number of pixels, for example, a pixel of 128 × 10 24 pixels or more (for example, 1920 × 1080 pixels) can be used. However, the projection efficiency was almost unchanged. Furthermore, by providing a polarization conversion element having a polarization separation unit and a polarization plane rotation unit in the illumination optical system, it is possible to achieve an extremely high projection efficiency of 12 lumens / watt. It has become possible.

 (Embodiment A 2 — 3)

 An example of an image display device that can effectively use a light beam transmitted without being reflected by a reflective hologram element will be described.

 As shown in FIG. 23, the image display device 241 is mainly different from the image display device 231 of the embodiment A 2-2 mainly in the hologram elements 2 16 to 21. The difference is that a total reflection mirror 2424, 243 or a dike-open mirror 2445 is provided on the back side of Fig. 8.

 That is, when a white light beam enters the dichroic mirror 2444 from the lamp 102 via the integrator 215, the blue light component of the incident light beam is Light that passes through and is reflected in other wavelength bands (red and green components, ie, yellow light).

The blue luminous flux is mainly reflected by the hologram element for blue 218 and converted into a parallel luminous flux, and then enters the image display element (liquid crystal panel) 221 for blue. The luminance is modulated. Further, the blue light beam transmitted without being reflected by the hologram element 2 18 is reflected by the total reflection mirror 2 43, passes through the hologram element 2 18 for blue again, and Incident on the image display element 22 1. That is, hologram element The luminous flux transmitted through the element 2 18 is also used effectively.

 The green luminous flux of the yellow luminous flux reflected by the dichroic mirror 244 is reflected by the green hologram element 217 and becomes a parallel luminous flux. After the conversion, the light enters the green image display element 220 and is subjected to luminance modulation. The green luminous flux transmitted without being reflected by the hologram element 211 is reflected by the dichroic mirror 245, and is again returned to the hologram element 211 for green. After passing through 7, the light enters the image display element 220 again.

 Further, the red luminous flux transmitted through the dichroic mirror 245 passes through relay lenses 246 and 248 for optical path length compensation and a total reflection mirror 247. The light enters the red hologram element 2 16, is mainly reflected, is converted into a parallel light beam, and then enters the red image display element 2 19 to be modulated in luminance. The red luminous flux transmitted through the hologram element 2 16 without being reflected by the hologram element 2 16 is reflected by the total reflection mirror 2 42, passes through the hologram element 2 16 for red light again, and then returns. The light enters the image display element 2 19.

 The luminance-modulated light fluxes of the respective colors are synthesized by a dichroic prism 235 and enlarged and projected by a projection lens 107 onto a screen (not shown).

As described above, the total reflection mirrors 242, 243 or the die-cloth mirror 245 are provided on the back side of the hologram elements 216 to 218. Therefore, most of the light flux transmitted through each of the hologram elements 2 16 to 2 18 without being reflected as a parallel light flux by each of the hologram elements 2 16 to 2 18 This light beam can be made incident on the image display element 2 19-2 21. Such a light beam is not converted into a parallel light beam, but is used for projecting an image. It is possible to obtain higher projection efficiency as compared with the case of using only. Specifically, for example, a liquid crystal panel with a diagonal dimension of 0.9 inches and a pixel of 1024 x 768 with an aperture ratio of about 40%, and an ultrahigh-pressure mercury of 100 W When the lamp is used, the projection efficiency when neither the micro lens nor the hologram element 2 16 to 2 18 is used is 3.6 lumens / unit. The projection efficiency when only the chrome lens was used was 4.3 lumens / unit, but as described above, the hologram element 2 16 to 21 By providing 8, a high projection efficiency of 10 lumens / unit could be obtained. This corresponds to an increase in the effective aperture ratio from 40% to about 90%. In addition, a liquid crystal panel having the same size and a large number of pixels, for example, a liquid crystal panel of 1,280 × 1,024 pixels or more (eg, 1,920 × 1,080 pixels) can be used. However, the projection efficiency was almost unchanged. In addition, by providing a polarization conversion element having a polarization separation unit and a polarization plane rotation unit in the illumination optical system, it is possible to achieve an extremely high projection efficiency of 12 lumens / watt. became.

 As a mirror provided on the back side of the hologram element 2 17, it is necessary to transmit a red luminous flux. Therefore, as described above, a green reflective and red transmissive die-cloth is used. In contrast to the necessity of using a mirror, the mirror provided on the back side of the hologram elements 2 16 and 218 is, as described above, a total reflection mirror (usually a mirror). A thin aluminum film formed on a glass substrate and, in some cases, a reflection-enhancing coating) may be used. Alternatively, a dichroic mirror that reflects a red light beam or a blue light beam may be used. You may use a la.

Further, as described above, the configuration in which the reflection mirror is provided on the back surface side of the hologram element is described in the embodiment A2-1 or the embodiment A2-2. The present invention may be applied to the following image display devices, etc., and the projection efficiency can be further improved.

 (Embodiment A 2 — 4)

 Describes an example of an image display device that uses a reflection-type and polarization-modulation-type liquid crystal display panel as an image display element and also uses a dichroic prism for color separation of white light flux. I do.

 As shown in FIG. 24, in the image display device 255 of the present embodiment A, as shown in FIG. 24, similar to the image display device described in the embodiment A 2-1 to 2-3, the lamps 10 2 The output light beam of the first lens is reflected by the reflector 103, and the reflected light beam is reflected by the first fly-eye lens 212 and the second fly-eye lens 212. The light is transmitted to the image display elements 260-262.

 Between the second fly-eye lens 2 13 and the image display device 260 to 262, there is a die-cloth prism 263 for color separation and a hologram element 26. 4 to 266 and PBS (polarized beam splitter) 2667 to 269 are provided. That is, the white output luminous flux from the lamp 102 is color-separated into three primary luminous fluxes of red, green and blue by the Die-Croix Bliss Bism 263, and is color-separated. The respective luminous fluxes are converted into desired luminous fluxes by the corresponding hologram elements 264 to 266, and the PBS 267-269 converts linearly polarized light having a predetermined polarization plane into a reflection type image. The light is incident on the display elements 260 to 262 and the polarization direction is modulated.

 The luminous flux of each primary color, the polarization direction of which has been modulated by the image display elements 260 to 262, is visualized again via PBS 267 to 269, and is projected by the projection lens 107. The image is enlarged and projected on a screen (not shown).

The hologram elements 2664 to 2666 are the same as those of the embodiment A2-1. In this way, basically, a two-beam interference draft of a reference light beam and an object light beam can be recorded on a general holographic material such as a photopolymer, for example. Here, the hologram elements 26 4 to 26 6 are such that the output light beam obtained by converting the incident light beam is substantially parallel light beam as in the case of Embodiment A 2-1 to 2-3. Alternatively, a convergent light beam having a small incident angle such that the polarization separation characteristics of PBS is not significantly reduced may be used. This makes it possible to achieve both high projection efficiency and high contrast while reducing the size of the device for the following reasons.

In general, the F value of an illumination optical system composed of a lamp, a reflector, a condenser lens, a relay lens, an integrator, a polarization conversion element, etc., and the F value of a projection lens The values are set so that they almost match, but the smaller the F value, the higher the projection efficiency. Incident angle increases. Here, PBS is generally formed such that a dielectric multilayer film is formed on a glass substrate so that incident light is separated into P-polarized light and S-polarized light. Dependent on the incident angle of light, the polarization splitting characteristics are degraded as it deviates from the reference incident angle at the time of design. Therefore, in the image display device using the reflective liquid crystal panel as described above, when the F value is small, the contrast tends to be lowered. Therefore, in order to improve the contrast, when the above-mentioned incident angle is reduced by the relay lens of the illumination optical system, the principle of so-called luminance invariance in so-called geometrical optics is used. As a result, the illumination area becomes large, and it is necessary to use a liquid crystal panel or the like having a large screen size, which leads to an increase in the size of the device. On the other hand, by using a holographic element as in Embodiment A, the incident angle is reduced so that the polarization separation characteristics of PBS are not significantly reduced. Even if the size is reduced, the lighting area can be reduced. Therefore, while miniaturizing the device using a liquid crystal panel having a small screen size, it is possible to configure an image display device that has high projection efficiency and does not reduce contrast.

Specifically, for example, a liquid crystal panel with a diagonal dimension of 0.9 inch and a pixel of 1024 x 768 with an aperture ratio of about 75%, and an ultrahigh-pressure mercury of 100 W When a lamp is used, in an image display device that does not use the hologram elements 2664 to 2666, the projection lens 107 and the F of the illumination optical system are used to secure the contrast. If the value is 4, the projection efficiency is about 2 lumens / watt, the contrast is 200: 1, and if the F value is 3, the projection efficiency is 4 lumens / watt. / watt and bright and wear with a force ^5, the co-down truss door 1 0 0: was reduced to 1. On the other hand, by providing the hologram elements 216 to 218 as described above, even if the F value is increased to 5, about 4.3 lm / The projection efficiency of watts can be achieved, and the F value is large (the incident angle with respect to PBS is small), so that the contrast can be improved to 800: 1.

 The image display elements 260 to 262 are not limited to liquid crystal panels, but are polarization-modulated, reflective image displays that reflect and output incident linearly polarized light after modulating its polarization direction. As long as it is an element, there are no restrictions on the light modulation material, light modulation method, pixel driving method, and the like.

 Further, the image display device configured in Embodiment A is a 3PBS system using three PBSs, but a 1PBS system using one PBS can also be configured.

Further, a pre-polarizer (PPBS) may be provided between the PBS and the holographic element of the present invention in order to improve the contrast of the projected image. (Embodiment A 2 — 5)

 Single-panel image display device having a dichroic mirror arranged at different angles with respect to the optical axis and an image display element formed with a micro lens array or the like Will be described.

 As shown in FIG. 25, this image display device 280 has two dichroic mirrors 281, 282 and one total reflection mirror 283. , A color separation having a hologram element 284 to 286 provided on the surface side of each die-cloth mirror 281, 282 or a total reflection mirror 283- Means 287, and an image display element 288 having a liquid crystal panel and an optical path changing means for changing the optical path of the incident light beam according to the incident angle are provided. The basic configuration and operation of this image display device 280 are described in “Nikkei Electronics”, January 30, 1995, page 169, page 173, and JP-A-8-2 The hologram elements 285 to 287 described above are similar to those described in Japanese Patent Application Laid-Open No. 9-25006 or FIG. 14 of Japanese Patent Application Laid-Open No. It is different in that it has.

That is, the dichroic mirrors 281, 282 and the total reflection mirror 2832 are arranged at different angles with respect to the optical axis, respectively, so that the white light from the lamp 102 is emitted. The output luminous flux is separated into three primary luminous fluxes of red, green, and blue. Has become. However, in this image display device 280, only the light flux transmitted through the hologram elements 284 to 286 depends on the die-cloth mirror 281, etc. as described above. power has become cormorants'll be reflected Te ^5, and related to this point will be described later. As an optical path changing means, for example, a micro lens array, a hologram lens array, a cylindrical lens, or the like is used, and the incident light flux is changed according to the incident angle. To the LCD panel Incident on pixels corresponding to different colors.

 With the above-described configuration, when a white light beam enters the color separation unit 2887 from the lamp 102 via the reflector 104 and the integration unit 21 Of the incident light beams, the light beam of the blue component is reflected by the hologram element for blue 284 and converted into a parallel light beam, and then enters the image display element 288 . The blue luminous flux transmitted without being reflected by the hologram element 2884 is reflected by the dichroic mirror 2811 for reflecting the blue luminous flux, and is again returned to the hologram for blue. After passing through the element 284, the light enters the image display element 288.

 Similarly, the luminous flux of the green component passes through the hologram element 284 for blue and the dichroic mirror 281 for reflecting blue luminous flux, and then passes through the hologram for green. The green luminous flux reflected by the element 285 and converted into a parallel luminous flux and incident on the image display element 288 and transmitted through the hologram element 285 is converted into a green luminous flux reflecting die. The light is reflected by the credit mirror 282 and then enters the image display element 288 again.

 Also, the luminous flux of the red component is holographic elements 284, 285 for blue and green, and a dich-mouth mirror 281, 28 for reflecting blue luminous flux and green luminous flux. After being transmitted through the hologram element 288, the light is reflected by the hologram element 286 for red and converted into a parallel light flux, enters the image display element 288, and transmits through the hologram element 286. The red light beam thus reflected is reflected by the total reflection mirror 283, and then enters the image display element 288.

The luminous flux of each color incident on the optical path changing means of the image display element 288 is incident on pixels corresponding to different colors on the liquid crystal panel in accordance with the respective incident angles, and is subjected to luminance modulation. Figure by 1 Enlarged projection on screen not shown. Here, since the luminous flux of each color reflected by the hologram elements 2884 to 2886 is converted into a parallel luminous flux as described above, each pixel of the liquid crystal panel corresponds to each color. Light is surely focused on the effective area. Therefore, the effective aperture ratio can be extremely increased, and a so-called black spot due to a part of the luminous flux of each primary color being incident on a pixel corresponding to another primary color. Loss can be minimized. Therefore, it is possible to display a clear image with no color mixture while taking advantage of the features of a single-panel system that has a simple optical system configuration and low cost, and at the same time, achieves projection efficiency and brightness of the projected image. The uniformity of the height can be improved.

 Specifically, for example, a liquid crystal panel 288 having a diagonal dimension of 1.3 inches and a pixel of 640 × 480 × 3 having an aperture ratio of about 40%, and 100 W When the ultra-high pressure mercury lamp and the holographic element 284 to 286 were not used, the projection efficiency was at most 1.5 lumens / watt. By providing the hologram elements 2884 to 2886 as described above, it is possible to obtain a high projection efficiency of 4 Lumens Z watts in spite of being a single plate type. Came out. Further, by providing a polarization conversion element having a polarization separating means and a polarization plane rotating means in the illumination optical system, an extremely high projection efficiency of 8 lumens / watt can be realized. Became possible.

 (Embodiment A3-11-1)

 An example of an image display device provided with a diffractive optical element instead of an integral lens having a first fly-eye lens and a second fly-eye lens will be described.

As shown in FIG. 26, this image display device has a lamp 102 and a lift. It is provided with a reflector 103, a diffractive optical element 301, an aspherical auxiliary lens 302, an image display element 303, and a projection lens 107. That is, the light beam emitted from the lamp 102 is reflected by the reflector 103 and is incident on the diffractive optical element 301, and the diffraction area of the diffractive optical element 301 described later is changed. The light beam diffracted for each 0a is superimposed on the image display area of the image display element 303 via the auxiliary lens 302, and the intensity is modulated, and is not shown by the projection lens 107. It is intended to be enlarged and projected on the screen.

 As the lamp 102, for example, an ultrahigh-pressure mercury lamp having a rated output of 120 Watts is used. In addition, not limited to the lamps described above, it is also possible to use various types as described in the embodiment A1-1. Here, it is more preferable that the light emitting region of the lamp 102 is small. However, even when the light emitting region is relatively large, the relative effects of the present invention can be obtained. It is also possible to use a lamp having a light emitting body as large as several millimeters, such as a lamp or a high-output metal halide lamp.

 As the reflector 103, for example, a parabolic mirror is used, but an elliptical mirror or a spherical mirror may be used. In the case of a parabolic mirror, the position where the lamp 102 is provided is preferably set such that the light-emitting area of the lamp 102 is located near the focal point of the parabolic mirror. In the case of a surface mirror, it is preferable to set it so that it is located near the first focal point, and in the case of a spherical mirror, it is located near the center of the sphere.

The auxiliary lens 302 ensures the telecentricity of the luminous flux incident on the image display element 303 and reduces the design load of the projection lens, that is, the F-number, etc. This is provided to alleviate the constraints of the projection lens.If the F-number of the projection lens has a design margin, it is not necessary to provide it. As shown in FIG. 27, the outer shape of the diffractive optical element 301 when viewed from the optical axis direction has a circular shape corresponding to the cross-sectional shape of the light beam incident from the reflector 103. The internal region is divided into a plurality of rectangular diffraction regions 310 a ... similar to the image display region of the image display element 303. Each of the diffraction regions 30 la diffracts the light beam incident thereon as described above, and makes the light beam enter over almost the entire image display region of the image display element 303. . In other words, the luminous flux output from each diffraction area 301a is superimposed on the image display element 303, so that the light quantity unevenness at the center and the periphery in the display image is reduced. It will be reduced.

The shape of each diffraction region 301a does not necessarily have to be a rectangular shape similar to the image display element 303, and may not be the same size or shape as each other. Further, the size and number of the diffraction region 301a are schematically illustrated for convenience in FIGS. 26 and 27, but are not particularly limited. That is, if the luminous flux output from each diffraction region 301 a is almost superimposed on the image display region of the image display element 303, the effect of reducing the light amount unevenness can be obtained. . However, in general, increasing the number of diffraction regions 301a can further improve the uniformity of the brightness of the projected image, and can improve the rectangular conversion efficiency (rectangular aperture ratio). By increasing the value, the projection efficiency can be increased, and a brighter image can be displayed. In addition, when the shape of the minute area 301 a is similar to the shape of the image display element 301, the output light flux from each diffraction area 301 a is superimposed on the image display element 303. This makes it relatively easy to fabricate. In addition, a luminous flux is superimposed on a partial area on the image display element 303 so as to cause a diffraction action in the area 30 lb around the rectangular diffraction area 301 a. You may let them do so. this In this case, the substantial rectangle conversion efficiency can be made 100%, and a brighter image can be displayed.

 The uniformity of the brightness of the projected image is further improved by slightly shifting the area of the image display element 303 where the output light beam from the diffractive optical element enters for each diffraction area 301a. You can improve it o

 As a specific diffractive structure of the diffractive optical element 301, for example, a surface relief type diffraction grating having a saw-tooth cross-sectional shape can be applied. The shape is not limited to the sawtooth shape, and may be a multi-level diffraction grating in which the sawtooth shape is approximated in a stepwise manner. The shape of the saw blade and the like can be determined by optical calculations and the like.

 The diffractive optical element 301 as described above can be manufactured by, for example, a general semiconductor process using an electron beam lithography method, and is easy to mass-produce. The manufacturing cost can be easily reduced to about 1/10 or less compared to the lens-based integration. Therefore, the integration cost, which occupies the majority of the manufacturing cost of the optical system elements together with the projection lens 107, is reduced, and the manufacturing cost of the entire image display device is reduced, for example, by the conventional method. It can be easily reduced to about 60%.

 Further, the diffractive optical element 301 may be manufactured by forming a holographic element using two-beam interference fringes as described in Embodiment A below.

As the image display element 109, various transmissive devices such as a transmissive liquid crystal panel can be used. Here, for example, a large number of disclosures have been made in Japanese Patent Application Laid-Open Nos. 1-28124 / 26, 3-140920 / 1992, and 4-251221. Each pixel has It is equipped with a compatible micro lens and converges the light beam incident on the image display element near the pixel aperture (effective area) to increase the effective aperture ratio. Is also good. For example, a high projection efficiency (light use efficiency) can be obtained even when the opening shape of the reflector 103 is set small to reduce the size of the device. That is, in the evening using the conventional fly-eye lens, each single lens of the first fly-eye lens corresponds to each single lens of the second fly-eye lens. It is provided so that However, if the aperture shape of the reflector is small, the deviation of the light beam output from the reflector from the parallel light tends to increase, and the parallelism of the light beam tends to decrease. In this case, a crosstalk is likely to occur between each single lens of the fly-eye lens. As a result, the image of the first lens array became considerably larger than the image display device, and the image display device could not be illuminated effectively.

On the other hand, when the diffractive optical element 301 is used as described above, the diffracted light beam by each diffraction region 301a of the diffractive optical element 301 is directly applied to the liquid crystal display element. The incident light does not cause a crosstalk as in the case of using two fly-eye lenses, and therefore, the parallel light of the light beam output from the refret evening Even if the deviation from the image becomes large, even if the parallelism of the luminous flux is slightly reduced, the illuminated area on the image display element 303 is only slightly displaced or widened. Since the substantial effect of increasing the aperture ratio due to the above is appropriately obtained, a high projection efficiency can be obtained. In addition, when a light source with low parallelism of the light beam output from the reflector, that is, a lamp with a relatively large light emitting area is used, it is assumed that an ideal parallel light beam is output. The area where the image display element is illuminated is set smaller than the image display area, and the entire image display element is illuminated due to a shift due to the output light beam not being a parallel light beam. You may be allowed to do so.

 As described above, by using a diffraction optical element instead of an integral lens having a fly-eye lens, it is possible to surely prevent unevenness in the amount of light at the center and the periphery of the displayed image. The projection efficiency can be improved as well as being reduced. Regarding the projection efficiency, for example, the conventional image display device has a projection efficiency of at most about 5 lumens / unit, whereas the image display device described above has a projection efficiency of 7.5 lumens / unit. It is possible to obtain watts and high efficiency.

 Further, since the opening shape of the reflector can be reduced without lowering the brightness of the display image, the size of the image display device can be easily reduced. Specifically, for example, the opening diameter of a conventional ordinary reflector is about 100 mm, but it can be reduced to about 50 mm, and the dimension in the optical axis direction is also conventional. It can be reduced to about 1/2 of the above. Further, it is easy to further reduce the size by reducing the F value of the projection lens and shortening the distance between the diffractive optical element and the image display element.

 (Embodiment A 3 — 2)

 Embodiment A An image display apparatus using a diffractive optical element similar to that of Embodiment 1, wherein the light from the light source is separated into light of three primary colors of red, green, and blue, and the light corresponding to each of these colors is corresponded. An example of a so-called three-plate image display device that displays a full-color image using three transmissive image display elements will be described.

As shown in FIG. 28, the image display device according to Embodiment A reflects the diffracted optical element 301 after reflecting the output light beam of the lamp 102 with the reflector 103 as shown in FIG. The illumination light flux of the image display element 3 14-3 16 is provided through the light source. Diffractive optical element 301 is the same as in Embodiment A3-1. It is like. In other words, a plurality of diffraction regions are formed, and the output light flux of each diffraction region is separated into three primary colors by dichroic mirrors 317 and 318, respectively. Are superimposed on the image display elements 314 to 316 for displaying the image.

 More specifically, in the white light flux output from the diffractive optical element 301, only the blue light flux is transmitted by the dichroic mirror 317, and other wavelength components are transmitted. Is reflected. The luminous flux of the blue component enters the image display element 314 for displaying a blue image via the reflection mirror 319. The green component of the reflected light from the die-cloth mirror 3 17 is reflected by the die-cloth mirror 3 18 and enters the image display element 3 15 for green. I do. The red component enters the image display element 316 for red display via the relay lenses 32 0 and 32 1 and the reflection mirrors 32 22 and 32 3. The luminous flux of each color incident on each of the image display elements 314 to 316 is modulated in brightness and then synthesized by the dichroic prism 324 for color synthesis to form a projection lens. It is enlarged and projected on a screen (not shown) by 107.

As shown in FIG. 29, the color composition may be performed by using the dichroic mirrors 339 and 340 without using the dichroic prism. . That is, the output light beam of the lamp 102 is condensed by the reflector 103 and then diffracted by the diffraction optical element 301 similar to that of the embodiment A3-1 to be separated for each diffraction area. The output luminous flux of each diffraction area is superimposed on the image display elements 314 to 316 via the dichroic mirrors 33 and 33 and the reflecting mirror 33 And modulates the brightness of the light, and converts the output luminous fluxes of the image display elements 314 to 316 into a color synthesis system consisting of dichroic mirrors 339 and 340 and a reflection mirror 341. By combining them, the projection lens 107 enlarges and projects them on a screen (not shown). Similarly, a full color image is displayed.

 In the image display device according to the embodiment A, similarly to the embodiment A3-1, an inte- grated lens is formed by using an inexpensive diffractive optical element instead of the conventional expensive pair of fly-eye lenses. With this configuration, it is possible to significantly suppress the increase in manufacturing cost, improve the projection efficiency, and reduce the outer diameter of the reflector. This makes it possible to reduce the thickness and weight of the image display device.

 The diffractive optical element 301 may be provided between the lamp 102 and the die-cloth mirror 317 as described above. It may be provided between the 317 and the like and the image display element 314 and the like.

 As a reflector, an elliptical mirror as in the following Embodiment A3-3, a spherical mirror, or a diffractive optical element may be used. A hologram element such as the form A3-4 may be used.

 (Embodiment A3-1-3)

An example of an image display device using an ellipsoidal mirror as a reflector will be described. As shown in FIG. 30, this image display device is different from the image display device of Embodiment A3-1 (FIG. 26) in that the reflector 103 is a parabolic mirror. The point that a reflector 353, which is an ellipsoidal mirror, is provided instead, and that the diffractive optical element 301 and the projection lens 107 are replaced by the reflector 353, The difference is that a diffractive optical element 351 and a projection lens 357 corresponding to the fact that the reflected light beam is a convergent light beam are provided, and other configurations and operations are the same. That is, when the light-emitting area of the lamp 102 is disposed at the first focal point of the reflector 3553, which is an ellipsoidal mirror, the reflected light flux from the reflector 3553 is almost equal to the second light. Focus on focus Be lighted. Since the diffractive optical element 351 is installed on the path of the reflected light beam, the diameter of the area of the diffractive optical element 351 where the reflected light beam enters, that is, the area where the diffracted light beam exits, is It is smaller than the outer diameter (opening diameter) of the receiver 35 3. Therefore, it is possible to reduce the outer diameter of the diffractive optical element 351, and to reduce the maximum incident angle of the diffracted light beam entering the image display element 303. Therefore, as the projection lens 357, a lens having a large F value and a low manufacturing cost can be used.

 It should be noted that a plurality of diffraction areas are formed in the diffractive optical element 351, and that the output light flux of each diffraction area is configured to be superimposed on the image display element, and the manufacturing method is also different from that of Embodiment A3 Same as 1.

 In addition, the effect of improving the projection efficiency, particularly the effect of improving the projection efficiency by improving the effective aperture ratio when using an image display element having a magic aperture lens, is described. This is the same as Embodiment A3-1.

 When the light emitting area of the lamp 102 is relatively large, the reflected light flux from the reflector 353 is not condensed at one point, but is a component collected before and after the second focal point. This causes a shift (for example, a diffraction image) in the image of the light source superimposed on the image display element 303. Therefore, when the degree of convergence of the reflected light beam is low, the deviation is anticipated from the beginning, and the setting is made so that the area of the diffracted light beam in each diffraction region that illuminates the image display element 303 becomes small. 2 Other portions may be illuminated with a light beam that is deviated from the light beam focused on the focal point.

 (Embodiment A 3 — 4)

Image using a holographic element produced by two-beam interference exposure or CGH (Computer Generated Hologram) as a diffractive optical element An example of a display device will be described.

 As shown in FIG. 31, this image display device is different from the image display device of Embodiment A3-1 (FIG. 26) in that the diffractive optical element 301 is replaced with the diffractive optical element 301. The optical axis of the lamp (103) and the lamp 103 and the reflector 102 (the optical axis of the illumination optical system) are aligned with the hologram element 361 and the projection laser. The difference is that the optical axis (the optical axis of the projection optical system) such as lens 107 is configured to form a predetermined angle, and other configurations and operations are the same.

 The hologram element 36 1 is a phase-type volume hologram, and is set so that the reflected light beam from the reflector 103 is incident at an incident angle of, for example, 30 °. . This is to eliminate the high-order diffracted light and increase the diffraction efficiency of the transmission hologram. The external shape of the hologram element 361 when viewed from its normal direction is formed as an ellipse having a major axis in the X-axis direction as shown in FIG. This is because, as is generally the case, since the output light beam from the reflector 103 is circular, the optical axis of the illumination optical system is not parallel to the optical axis of the projection optical system. This is because the circular image projected on the hologram element 361 has an elliptical shape as shown in FIG.

Like the hologram element 301 of the embodiment A3-1, a plurality of rectangular diffraction areas 361a are formed in the internal area of the hologram element 361. The shape of each rectangular diffraction area 36 la draws the image display area of the image display element 303 in the vertical direction by the ratio of the long axis to the short axis in the outer shape of the hologram element 36 1. It is formed to be similar to the elongated shape. In FIG. 32, the image display element 303 displays a so-called noise-vision (HDTV) image having an aspect ratio of 16 (horizontal direction): 9 (vertical direction). Example of case Is represented.

 Note that, as described in Embodiment A3-1, the shape of the diffraction region 361a does not necessarily have to be a shape corresponding to the image display element 303. It is not necessary that they have the same size or shape. That is, the size, shape, and number of the diffraction regions 361a are not particularly limited, and the luminous flux output from each diffraction region 36la is reflected on the image display region of the image display element 3663. If they are almost superimposed, the effect of reducing the amount of light can be obtained.

 Note that, even when the optical axis of the illumination optical system and the optical axis of the projection optical system are not parallel as in Embodiment A, a surface relief type diffractive optical element can of course be used. Wear.

 Next, a method for manufacturing the hologram element 361 will be described. The holographic element 361 can be manufactured by recording a calculated draft in a photo register by electron beam lithography or the like. The case of manufacturing by exposure of an interference draft such as a polymer will be described.

In general, a holographic element degrades two coherent light beams (a reference beam and an object beam), and records the generated interference image by exposing a recording material such as a photopolymer. It is produced by As the reference light, a light flux substantially equal to the output light flux from the reflector may be used. For example, when a parabolic mirror is used for the reflector 103 as described above, parallel light may be incident at an angle parallel to the optical axis of the actual illumination optical system. Also, as the object light, the light enters from the area where each diffraction area 36 la is to be formed to the entire display area of the image display element 303 and is superimposed on the image display element 303. A light beam having such a light path is used. Hereinafter, a specific description will be given based on FIGS. Figure 33 shows the hologram FIG. 7 is a layout diagram of an interference exposure system when recording a draft in one region 371a where a diffraction region of a film material 371 is to be formed.

 As the hologram material 37 1 for manufacturing the hologram element 36 1, various materials as described in Embodiment A 11 can be used.

 The parallel light beam L output from the laser 372 is split into a transmitted light M and a reflected light N by a half mirror 373.

 The transmitted light M passes through the opening 375 a provided in the mirror 374 and the mask 375 corresponding to the region 371 a of the hologram material 371. At a predetermined incident angle, the light enters the region 371a of the hologram material 371 as reference light. The above-mentioned predetermined angle of incidence refers to the optical axis of the reflector 103 (the rotation axis of the paraboloid of revolution) and the normal of the hologram element 361, in the image display device actually configured. The angle is the same as the angle between the two.

 On the other hand, the reflected light N is condensed by the condensing lens 376, passes through the opening 375a of the mask 375, and then passes through the auxiliary lens 372 to the display area of the image display element 373. Is converted into a luminous flux that illuminates substantially the same area as above, and enters the area 371a of the hologram material 371 as object light.

 As described above, by recording an interference image formed by two light beams incident on the hologram material 371 into the hologram material 371, one diffraction region is formed. This is sequentially repeated for each diffraction region, thereby producing the holographic element 3651 as described above.

Another method for fabricating the hologram element 36 1 will be described. In this method, the reference light is the same as the above case, but the lens array 381, as shown in Fig. 34, is used to generate the object light. Used. In this lens array 381, a lens 381a corresponding to each region 371a in which the diffraction region of the hologram material 371 is to be formed is formed. Each lens 3811a acts like a focusing lens 3776 in the above-described manner for each area 371a of the hologram material 371, respectively. I have.

 Here, the exposure of the hologram material 37 1 may be performed for each region 3 71 a by using a mask 3 75 as in the method described above. By using a mask 382 as shown in 34, it is possible to simultaneously expose a plurality of regions 371a. The mask 382 has openings 382a corresponding to the respective lenses 381a of the lens array 381, and the respective areas 371a of the hologram material 371, respectively. The regions of the hologram material 371, on which the object light is incident via the respective lenses 38 la, are formed such that they do not substantially overlap with each other and that there are no gaps. I have.

 In the case of an image display device that uses an ellipsoidal mirror instead of a parabolic mirror as in Embodiment A3-5 described below, the reference light is used as the reference light. Instead of a parallel light beam, a light beam equivalent to the light beam converged on the second focal point in the actual illumination optical system may be used. Such a light beam can be easily obtained by arranging a lens having a predetermined refractive power in the optical path of the transmitted light M on the optical axis of the reflex.

 In addition, by using various methods as described in the embodiment A1-1, the reference light and the object light may be generated to form the respective diffraction regions 361a.

 (Embodiment A 3 — 5)

As shown in Fig. 35, the hologram element 39 was used as the diffractive optical element. In addition to using 1, an ellipsoidal mirror 353 may be used as a reflector.

 That is, the diffracting area 391a is located on the path where the output light beam from the lamp 102 is converged to the second focal point by the reflection mirror 3553 composed of an ellipsoidal mirror. The formed hologram element 391 may be arranged. As a result, the diffracted light beam from each diffraction area 391a of the hologram element 391 is incident on the image display element 303 via the auxiliary lens 302 (can be omitted). . The output luminous flux of the image display element 303 is enlarged and projected on a screen (not shown) by the projection lens 357.

 As described in the embodiment A3-4, the hologram element 391 serves as a reference beam and reflects the light to be focused on the second focal point from the reflector 353 as described above. It can be manufactured by using a light beam equivalent to the light beam as the reference light.

 Also in the image display device as described above, similarly to the image display device of Embodiment A3-3, the hologram element 391 can be arranged close to the second focal point to be small. As a result, the manufacturing cost can be reduced by reducing the maximum incident angle of the illumination light beam entering the image display element 303, and the micro lens of the image display element 303 can be reduced. The effect of improving the projection efficiency by increasing the gain can be obtained.

 (Embodiment A3-6)

 As shown in FIG. 36, a reflective hologram element 401 may be used.

For example, a so-called volume hologram is used as the reflective hologram element 401. The hologram element 401 is arranged so that its normal forms an angle of, for example, 45 ° with the optical axis of the illumination optical system and the optical axis of the projection optical system. Are formed, each The diffracted light output from the diffraction area 401 a is superimposed on the image display element 303. Such a hologram element 401 can also be manufactured by the method described in the embodiment A1-1 or the embodiment A3-3. As a reflector, an ellipsoidal mirror or a spherical mirror may be used as in Embodiment A3-5.

 (Embodiment A 3 — 7)

 A holographic element is used as the diffractive optical element, a dichroic prism is used for color separation and color synthesis, and a transmissive display element is used as the image display element. An example of a three-plate image display device for displaying a full-color image will be described.

 In this image display device, as shown in FIG. 37, a white output light beam of a lamp 102 is condensed by a reflector 103 and is condensed by a mirror 104. After being reflected, it is incident on a dichroic prism 415 for color separation, and is split into light beams of three primary colors. The luminous flux separated into each color is incident on a reflective hologram element 4 16 to 4 18 in which a plurality of diffraction regions similar to those in Embodiment A 316 are formed, and is diffracted in each diffraction region. The luminous flux is superimposed on the transmission type image display elements 422 to 424 via the mirrors 419 to 421 to be luminance-modulated, and the dike opening prism is performed. After being synthesized by 4 25, the image is enlarged and projected on a screen (not shown) by a projection lens 107. Also in the image display device as described above, the manufacturing cost can be reduced and the projection efficiency can be improved.

Each of the hologram elements 4 16 to 4 18 has a higher peak because the wavelength dispersion peak of the diffraction efficiency is included in the wavelength band of the incident light flux. Efficiency can be achieved. In particular, As a laser beam at the time of making a hologram, a laser beam having a wavelength of each incident light beam may be used.

 Further, the reflector is not limited to a parabolic mirror, but may be an ellipsoidal mirror, a spherical mirror, or the like.

 Further, instead of the hologram element, a relay type diffractive optical element as shown in Embodiment A3-1 may be used.

 (Embodiment A3-8)

 An example of an image display device different from Embodiment A3-7 in that a reflective display device is used as the image display device will be described.

 In this image display device, as shown in FIG. 38, the white output light beam of the lamp 102 is condensed by the reflector 103, and is condensed by the mirror 104. After being reflected, it is incident on a dichroic prism 415 for color separation, and is split into light beams of three primary colors. The light beam separated into each color is incident on a reflective holographic element 4 16-4 18 in which a plurality of diffraction regions similar to those in Embodiment A36 are formed, and is diffracted by each diffraction region. The luminous flux is superimposed on the reflection type image display elements 434 to 436 via PBSs 431 to 433 and is subjected to luminance modulation. After being synthesized by the dichroic prism 425 through the projection lens 107, the projection lens 107 expands the image onto a screen (not shown). Has become.

 As the reflection type image display elements 434 to 436 described above, polarization type image display elements such as an electric writing type or an optical writing type reflection type liquid crystal panel are used. be able to.

 Even in the case of such a configuration, the effects of reducing the manufacturing cost and improving the projection efficiency are the same.

(Embodiment A 3 — 9) An example of an image display device in which the configuration of Embodiment A3-2 (FIG. 28) is further provided with a polarization conversion element will be described.

 In this image display apparatus, as shown in FIG. 39, the output light beam from the lamp 102 is substantially parallel reflected light beam by a parabolic mirror reflector 103, for example. And a slit-like shape by a cylindrical lens array 44 1 of the polarization conversion elements 4 44 arranged longitudinally in the direction perpendicular to the paper of FIG. The light is condensed to form an elongated slit near the focal point of the cylindrical lens. The polarization separating element 442 and the polarization plane rotating means 4443 are arranged near the focal point and output a light beam in which the polarization direction of the reflected light beam from the reflector 103 is aligned in a specific direction. It is supposed to be done. A diffractive optical element 301 having a plurality of diffraction regions is provided on the path of the output optical path. Other configurations are the same as those in Embodiment A3-2 (FIG. 28).

 In this image display device, the brightness of the projected image is changed in the same manner as in Embodiment A3-2 (FIG. 28), except that the polarization direction is changed by the polarization conversion element 444. An image with high uniformity is displayed.

 As described above, by combining the diffractive optical element 301 having the function as an integral element and the polarization conversion element 444, it is possible to realize a higher projection efficiency. it can.

 The same effect can be obtained by combining a polarization conversion element with a configuration in which color is combined by a dichroic mirror as in Embodiment A3-2 (FIG. 29). .

 (Embodiment A 3 — 10)

As shown in FIG. 40, the image display device of the embodiment A includes the same diffractive optical element 301 as that shown in the embodiment A3-2. The image display device further includes a reflective hologram element 399 having the same function as the hologram element 105 described in Embodiment A1-1 and the like. It is configured. Other configurations are the same as those in Embodiment A3-2. As a result, when the light emitting area of the lamp 102 has a certain size, or when the reflector 103 is a parabolic mirror, an elliptical mirror, a spherical mirror, or the like, In either case, the hologram element 39 9 causes the reflected light flux from the reflector 103 to be the same as when an ideal point light source and a desired reflex camera are used. Is converted into a parallel light beam or a convergent light beam, so that a high projection efficiency can be obtained, a high projection efficiency can be obtained, and each of the components formed in the diffractive optical element 301 can be obtained. Since the luminous flux output from the diffraction region is superimposed on the image display element 3114-316, it is possible to reduce the unevenness in the light amount at the center and the periphery of the display image.

 The hologram element 39 9 may be a transmissive element similar to that of the embodiment A1-1 or the like, while a diffractive optical element 301 is a reflective element. May be used.

 Further, as the liquid crystal display element, a reflection type liquid crystal display element having a configuration as shown in FIGS. 15 and 24 may be used.

 Further, the polarization conversion element or the like described in Embodiment A108 may be provided so that the projection efficiency can be further increased.

In each of the above examples, a liquid crystal panel is used as an image display element. This liquid crystal panel is, for example, disclosed in Japanese Patent Application Laid-Open Nos. As disclosed in a number of publications such as Japanese Patent Publication No. Hei 4 (1995) -212, a single micro lens is disposed for each pixel, and the incident light flux is reduced to the vicinity of the opening of the pixel. Any image display device that has a function of increasing the effective aperture ratio by converging light to the target can be used. There are no restrictions on the preparation method, light modulation method, and pixel driving method.

 That is, various liquid crystal materials such as vertical nematic liquid crystal (hereinafter abbreviated as TN liquid crystal) and various liquid crystal materials such as vertical alignment liquid crystal (hereinafter abbreviated as VA liquid crystal), or electro-optical effect. It is also possible to use a polarization type image display element using an optical material having optical anisotropy such as an optical crystal having the following. In addition to a polarization type image display device, a scattering type image display device that displays an image by dispersing an incident light beam using a polymer dispersed liquid crystal (hereinafter abbreviated as PDLC) may be used. It is possible.

 Further, for example, a diffraction type image display device as disclosed in Japanese Patent Application No. 7-284759 can be used.

 Further, as the driving of the element, not only the TFT but also an image display element using a thin film diode (hereinafter abbreviated as TFD) can be used. High-temperature polycrystalline silicon (hereinafter abbreviated as high-temperature P-Si) and low-temperature polycrystalline silicon (hereinafter, low-temperature p-Si) are used as materials for forming driving elements such as TFTs and TFDs. An image display element using amorphous silicon (hereinafter abbreviated as a-Si) can also be used.

 Also, a large number of transmissive liquid crystal panels are disclosed in, for example, Japanese Patent Application Laid-Open Nos. Hei 1-284124, Japanese Patent Laid-Open No. Hei 3-14092, Japanese Patent Laid-Open Hei 4-251221, and the like. Alternatively, one micro lens may be arranged for each pixel, and a function that increases the effective aperture ratio by converging the incident light flux near the pixel opening may be used. In addition, there are no restrictions on the light modulation material, light modulation method, and pixel driving method.

In other words, such as vertical nematic liquid crystal (hereinafter abbreviated as TN liquid crystal), vertically aligned liquid crystal (hereinafter abbreviated as VA liquid crystal), etc. It is also possible to use a polarization type image display device using an optical material having optical anisotropy such as various liquid crystal materials or an optical crystal having an electro-optical effect.

 In addition to the polarization type image display device, a scattering type image display device which displays an image by scattering an incident light beam using a polymer dispersed liquid crystal (hereinafter abbreviated as PDLC) is used. Can also.

 Further, for example, a diffraction type image display device as disclosed in Japanese Patent Application No. 7-284759 or a light deflection type image display device called a so-called DMD device can be used. .

 In addition, an active matrix method (hereinafter abbreviated as AM method) in which a driving element is formed in each pixel, and a simple (passive) matrix in which elements are directly driven by simple matrix electrodes. An image display element of any of the driving methods of the matrix method (hereinafter abbreviated as PM method) can be used. In addition, as the lamp, a metal halide lamp, a metal lamp, a logen lamp, a xenon lamp, an ultra-high pressure mercury lamp, or the like can be used. Although it is preferable that the light emitter is smaller, the present invention does not necessarily require that the light emitter be smaller, for example, a high-power xenon lamp or a high-power metal halide lamp. As shown in the figure, a lamp with a large number of luminous bodies of several millimeters is acceptable.

 It is preferable to use a parabolic mirror, an ellipsoidal mirror, or a spherical mirror as a reflector corresponding to the light collecting means in the present invention. At that time, it is preferable to install the illuminant of lamp 2 near the focal point in the case of a parabolic mirror, near the first focal point in the case of an ellipsoidal mirror, or near the center of a sphere in the case of a spherical mirror. New

In addition, although the dichroic mirrors 15 and 16 are used for the color synthesizing system, the color synthesizing system may be configured using a dichroic prism. Ma Instead of using the color synthesizing system, the output luminous fluxes from the three liquid crystal panels may be projected using the corresponding three projection lenses and synthesized on a screen. It is also possible to use dichroic prism for the color separation system.

 Further, when the image display element is of a polarization type like a liquid crystal panel, the illumination optical system of the present invention is further improved by adding a polarization conversion element comprising a polarization separation means and a polarization plane rotation means. It is possible to further improve the projection efficiency. Examples of the polarization conversion element include, for example, JP-A-5-107505, JP-A-6-220904, JP-A-7-294096, As disclosed in Japanese Unexamined Patent Application Publication No. 8-2,324,05 and Japanese Unexamined Patent Application, First Publication No. Hei 9-105,936, it is composed of a combination of a polarization splitting means and a polarization plane rotating means. Any polarization conversion element can be used. Regardless of which polarization conversion element is used, the basic configuration of the optical system and the method of manufacturing a holographic element described below do not change.

 Further, various configurations shown in each embodiment A may be combined.

 The hologram element and the image display device using the hologram element according to the present invention can be variously modified in accordance with the gist of the present invention. It is not limited.

♦

 (Embodiment B 1)

 An example of a holographic element which is a polarization selective diffraction optical element having a different diffraction effect according to the polarization direction of incident light will be described.

As shown in FIG. 10, this hologram element has two galvanized elements each having a conductive transparent electrode (hereinafter referred to as “IT 0”) 501 formed thereon. For example, a region 503 containing an ultraviolet-curable liquid crystal (hereinafter, referred to as a “UV-curable liquid crystal”) molecule 503 a and a non-polymerizable liquid crystal molecule 504 a are disposed between the substrate 502 and the substrate. Region 504 is formed. The UV-curable liquid crystal is a photocurable liquid crystal having a refractive index anisotropy, which is cured by a light beam having a specific wavelength. On the other hand, a non-polymerizable liquid crystal is a liquid crystal material that does not cure with respect to a light beam having a wavelength that cures the UV-curable liquid crystal.

Here, the expression regarding “optical anisotropy” will be described. In general liquid crystal materials and optical materials having refractive index anisotropy as seen in uniaxial optical crystals, it is possible to define the refractive index for ordinary rays and the refractive index for extraordinary rays. Wear. The ordinary ray is a polarized light whose refractive index does not depend on the incident angle of the light ray, and the extraordinary ray is a polarized light having a different refractive index depending on the incident angle. The refractive index of an extraordinary ray corresponding to the angle of incidence is the so-called refractive index ellipsoid shown in Fig. 3 (b) (references: e.g. (Page 2). Therefore, "optical anisotropy of each region with respect to the incident light beam" is abbreviated to "optical anisotropy of each region" unless otherwise specified. It is assumed that the anisotropy j of the ordinary index for the light beam and the refractive index for the extraordinary ray j. And the refractive index for extraordinary rays are substantially equal to each other in both regions. " Similarly, "different optical anisotropy between region 503 and region 504" means "the refractive index for incident ordinary light is almost equal in both regions, but the refractive index for extraordinary light is Are different in both areas. " In addition, "optical anisotropy" "Fold index anisotropy" is used in the same meaning.

 In the above hologram element, when no voltage is applied between IT 0501, as shown in FIG. 10 (a), both the region 503 and the region 504 have liquid crystal molecules 503. a and 504a are oriented in substantially the same direction (direction substantially parallel to the glass substrate 502), and the optical anisotropy of the region 503 (after curing) and the region 504 are almost equal to each other. It's getting better. That is, the refractive indices for the ordinary ray in the region 503 and the region 504 are almost equal (the value is no), and the refractive index for the extraordinary ray is almost equal (the value is ne). And). On the other hand, when a predetermined voltage is applied between the ITO 504, only the liquid crystal molecules 504a in the region 504 are oriented in the direction of the electric force lines, as shown in FIG. 10 (b). (Switching), so that the region 503 and the region 504 have different optical anisotropy from each other.

The hologram element configured as described above functions as a hologram element for P-polarized light (extraordinary ray) by applying a voltage between ITO 50 and incident. The light beam is diffracted in a direction according to the pitch between the region 503 and the region 504 and the film thickness. That is, only the P-polarized light is selectively diffracted, and the S-polarized light (ordinary ray) goes straight (Fig. 10 (b)). The selective diffraction of only the P-polarized light is the same even when the light beam enters the hologram element from an oblique direction. On the other hand, when no voltage is applied, both the P and S polarized lights go straight (Fig. 10 (a)). In addition, in this hologram element, when no voltage is applied, even when the light enters from an oblique direction, both the P and S polarized lights can be surely made to go straight. That is, as shown in FIG. 11, when a light beam is incident from an oblique direction, the refractive index for ordinary light is not only equal to n0 in the regions 503 and 504, but also for the extraordinary light. Well, area 5 Both 0 3 and 504 are equal in ne (S), so that not only ordinary rays but also extraordinary rays can travel straight without diffracting.

 As described above, according to the hologram element described above, it is ensured that an ordinary ray and an extraordinary ray can be made to go straight, and that only an extraordinary ray can be selectively applied to an obliquely incident luminous flux. It can be diffracted to a point.

 Next, a method for manufacturing the hologram element as described above will be described. This holographic element can be formed by so-called light-induced phase separation, for example, by irradiating an interference image of two light beams.

 (1) First, an alignment film (not shown) is applied to two glass substrates 502 on which IT 0501 has been formed, and an alignment process is performed.

 (2) A cell gap is secured by dispersing beads (not shown) having a predetermined diameter, for example, and two glass substrates 502 are bonded together (instead of dispersing beads, silicon oxide is used). (4) A column having a predetermined height made of a photopolymer may be formed.)

 (3) For example, non-polymerizable liquid crystal and UV-curable liquid crystal

A liquid crystal material mixed at a weight ratio of 1 is injected and sealed.

 (4) Two-beam interference exposure irradiates an interference image of a desired pitch, cures the UV-curable liquid crystal in the area where the light was strongly irradiated, and causes the mixed liquid crystal by the light-induced phase separation phenomenon. Most of the UV-curable liquid crystal molecules in the center are gathered in the cured portion, and good region separation is performed.

Here, in the above process (4), two light flux interferences are caused in a state in which a voltage is applied between IT 〇 501 and the liquid crystal molecules are oriented substantially vertically on a glass substrate 501, for example. When the exposure is performed, as shown in Fig. 12, when a voltage is applied, the optical anisotropy becomes almost equal, and both the P-polarized light and the S-polarized light in the incident light beam go straight. In this case, the optical anisotropy of each region becomes different, and only the P-polarized light is By folding, a hologram element in the reverse mode in which the S-polarized light travels straight can be manufactured.

 In general, it is preferable to apply an AC voltage as a driving method of the element. However, when a non-polymerizable liquid crystal, for example, a ferroelectric liquid crystal is used, its memory uniformity is reduced. A pulsed voltage may be applied taking advantage of this.

 Here, the difference between the hologram element of the present invention and the conventional hologram element will be described. For example, the above operation principle is basically the same as that of the conventional example 1, but the conventional example 1 merely uses a photocurable polymer material for the region 503, and has a refractive index anisotropy. Is not disclosed at all. In contrast, in the hologram element of the present invention, the photocurable liquid crystal has a refractive index anisotropy, and ne and no after curing are the same as the non-polymerizable liquid crystal in the region 504. This is a characteristic, and therefore, the incident angle characteristics can be improved. For example, consider a vertically incident light beam (see Fig. 2 (a)).

 In Conventional Example 1, the region 503 made of a photocurable polymer material does not have a refractive index anisotropy, so that the refractive index is always a value n1 which is substantially equal to n0 of the liquid crystal. In the first conventional example, by controlling the liquid crystal molecules and adopting a configuration as shown in FIG. 8A, the incident light beam 3 can travel straight without diffracting.

However, as shown in Fig. 9 (a), for the light beam 3, which is obliquely incident, the ordinary ray (in this case, S-polarized light 5) can go straight, but the extraordinary ray (in this case, P-polarized light) The light 4) is diffracted because the refractive index of the region 504 is 116 (5), while the refractive index of the region 503 is n0. As shown in Fig. 9 (b), the refractive index for an extraordinary ray can be obtained from a refractive index ellipsoid. The above phenomenon is disclosed in, for example, Conventional Examples 2 to 6. As described above, this is a problem common to all conventional devices in which the polymer material to be cured does not essentially have refractive index anisotropy.

 Although Conventional Example 6 is not a holographic element, it does not disclose the refractive index between the photocurable polymer material and the non-polymerizable liquid crystal. In this case, the polymer material is not used. The problem is the slight refractive index anisotropy that occurs when formed in a narrow-gap cell.

 (Embodiment B 2 1 1)

 An example of a polarization splitting element configured using a hologram element will be described. This polarization separation element separates an incident light beam into, for example, S- and P-polarized light, and emits both light beams at slightly different emission angles. For example, a polarization converter for obtaining a light beam with a uniform polarization direction Used for devices.

 As shown in FIG. 13, the polarization separation element 510 is configured by laminating a first hologram element 511 and a second hologram element 512. . When a light flux α substantially parallel to the normal direction of the first holographic element 5 11 (the Z-axis direction in the figure) is incident, for example, the S-polarized component (polarization plane parallel to the X-axis shown in the figure) The polarized light component is diffracted and emitted at an emission angle of, for example, 45 ° (the angle between the 法 axis and the direction of propagation of the incident light with respect to the substrate normal, that is, the Ζ axis). The light is incident on the program element 512 at an incident angle of 45 °. On the other hand, the Ρ-polarized light component (a polarized light component having a plane of polarization parallel to the Υ-axis) is transmitted through the first hologram element 511 as it is.

The S-polarized light that has entered the second hologram element 512 at an incident angle of 45 ° is diffracted by the second hologram element 512, for example, 17 °. While the 、 -polarized light is transmitted parallel to the Ζ-axis in the same manner as in the first hologram element 511. That is, the polarization beam splitter 510 can separate and output the P-polarized light and the S-polarized light with a difference in the traveling direction of 7 °.

 As the hologram elements 5 11 and 5 12, for example, the hologram elements of Embodiment B1 can be used. In this case, the hologram elements of the respective hologram elements can be used. By applying a predetermined voltage to ITO, the above operation can be performed. In addition, a hologram element that performs the above-described diffraction without applying a voltage may be used. Such a hologram element can be manufactured, for example, as follows.

 (1) A conductive transparent electrode (for example, I T0: not shown) is formed on a pair of glass substrates 25.

 (2) An alignment film (not shown) is applied on each conductive transparent electrode, and a rubbing process is performed.

 (3) Disperse spherical beads (not shown) having a desired diameter on the conductive transparent electrode.

 (4) Apply a sealing material (not shown) to the periphery of the glass substrate 5 13.

 (5) Laminate the glass substrates 5 13 and 5 14 and cure the seal material by heat treatment.

 (6) For example, UV curable liquid crystal 515 is injected as a hologram material from an inlet (not shown).

 (7) The UV-curable liquid crystal 515 is exposed by a two-beam interference optical system using one UV laser beam to form a predetermined interference document described later.

 (8) Irradiate UV light again while applying a predetermined voltage between the conductive transparent electrodes.

It should be noted that such a cell is manufactured by a technique known in the field of optics. There is also a two-beam interference optical system that divides a coherent laser beam into two and irradiates the laser beam at a predetermined angle to form an interference image in a predetermined direction and pitch. Technology.

 Next, the principle of forming a holographic element having polarization selectivity by the above manufacturing method will be described. UV-curable liquid crystals are liquid crystals that cure when irradiated with UV light, for example, light having a wavelength near 360 nanometers. Due to the rubbing treatment of the above (2), the molecules 515a of the liquid crystal are generally in a state after the injection of the (6) and before the UV exposure after the (7), as schematically shown in FIG. It is oriented in the rubbing direction.

 In this state, as described later, when an interference draft formed by the two-beam interference optical system is irradiated on the UV-curable liquid crystal 515, the UV-curable liquid crystal 515 reduces the light intensity of the interference draft. It cures accordingly. Specifically, for example, as schematically shown in FIG. 15, when an interference fringe having a light intensity distribution in the Y-axis direction in FIG. 15 is formed, only the liquid crystal molecules 515 b in the strong portion are formed. Hardens.

After that, when a voltage is applied between the conductive transparent electrodes, as shown in Fig. 16, only the liquid crystal molecules 515a of the part where the light intensity was weak in the 1000 manuscripts were aligned in the direction of the electric force lines ( Switching). When the entire surface is irradiated with UV light again in this state, the hologram element maintains the alignment state of the liquid crystal molecules as shown in Fig. 16 even when the application of the voltage is stopped. In other words, the switching area and the non-switching area of the liquid crystal are formed by minute pitches in the interference draft. Therefore, since the liquid crystal molecules have optically uniaxial refractive index anisotropy, in the example of FIG. 16, the polarization component oscillating in the X-axis direction is a phase-type diffraction element. In contrast to the element that acts, the element is isotropic with respect to the polarization component oscillating in the Y-axis direction. Thus, it functions as a diffraction element having polarization anisotropy that outputs without diffraction.

 In the present embodiment B, specifically, the hologram elements 511 and 512 were manufactured according to the following parameters.

 The tilt angle of the interference hologram of the first hologram element: 22.5 °

 Pitch of interference draft of first hologram element: 0.757 〃m Thickness of first hologram element: 9 〃m

 The tilt angle of the interference hologram of the second hologram element: 19 °

 Pitch of interference draft of second hologram element: 0.651 0m Thickness of second hologram element: 9 m

 Average refractive index of liquid crystal: 1 · 5 9 3

 Refractive index change: 0.083 FIG. 17 shows the diffraction efficiency for S-polarized light of the polarization separation element 510 manufactured as described above. The horizontal axis is the angle of incidence on the first hologram element 5 1 1. As shown in the figure, high polarization separation characteristics of 90% or more were achieved in the range of ± 2 °.

 When a UV-curable liquid crystal that can be oriented by a magnetic field is used as the liquid crystal material, it is not necessary to form a conductive transparent electrode on the surfaces of the glass substrates 5 13 and 5 14. In the process of (8), a magnetic field may be applied instead of applying an electric field.

 In addition, using a mixture of a photopolymer and a liquid crystal polymer having sensitivity to a specific wavelength region as the hologram material 27, the hologram material is formed by photoinduced phase separation. A program element may be manufactured.

Further, in Embodiment B, the optical axis defined as the normal to the glass substrates 5 13 and 5 14 and the incident light flux approximately coincide with each other, but the They do not need to match.

 As the hologram element used for the above-mentioned polarization splitting element, for example, the one shown in FIG. 18 can be used. This hologram element 52 1 is formed using an optical medium 52 2 having a refractive index anisotropy such as a liquid crystal, and has a thickness of about 1 Om. The distribution is periodically distributed also in the thickness direction. For this reason, the diffracting action differs depending on the polarization direction, and the diffracting action has a characteristic of exhibiting high diffraction efficiency in one direction.

 Hereinafter, the hologram element 5 21 will be described in detail.

 The inside of this element has a layered structure in which a layer inclined in the thickness direction is periodically formed from the surface on which light is incident. The layers adjacent to each other are arranged such that the tilt of the optical axis of the optical medium 52 2 having refractive index anisotropy is parallel to the surface of the hologram element 52 1. The other is arranged perpendicular to the surface.

 When light is incident on the optical medium 52 2 having the above-mentioned refractive index anisotropy, if the polarization direction of the light is parallel to the optical axis of the optical medium 52 2, the light becomes an extraordinary ray, so that the refractive index is determined. The value of Ne. When the polarization direction is perpendicular to the optical axis of the optical medium 522, it is an ordinary ray and shows a refractive index of No. Here, Ne> No.

 Next, in the hologram element 521 shown in FIG. 18, light having a polarization direction perpendicular to the paper surface is regarded as an ordinary ray, and light having a polarization direction parallel to the paper surface is regarded as an extraordinary ray. Then, the behavior when these lights enter the hologram element 52 1 will be described.

First, when an ordinary ray is incident, its polarization direction is perpendicular to the optical axis of any of the optical media 522 constituting each layer. For this reason, the refractive index of each layer is N o irrespective of the direction of the optical axis between the layers. One In addition, since it is equivalent to the existence of a uniform medium having a refractive index of No, ordinary rays incident on the medium are not affected by diffraction, and are transmitted as they are, as shown in the figure. And

 On the other hand, when an extraordinary ray is incident, the polarization direction of the incident light is parallel to the optical axis in the layer where the optical axis of the optical medium 522 having the refractive index anisotropy is arranged parallel to the incident surface. Becomes This corresponds to the case where the light passes through a layer having a refractive index of Ne. Also, for a layer in which the optical axis of the optical medium 52 2 is perpendicular to the incident surface of the hologram element 52 1, this corresponds to the case where the polarization direction is perpendicular to the optical axis. Layer acts with a refractive index of N o. Therefore, for an extraordinary ray, the hologram element 521 passes through a plurality of layers having different refractive indexes periodically in the thickness direction which is the traveling direction of the incident light. become. As a result, the incident light beam is subjected to the so-called Bragg diffraction effect, in which the light is condensed in a specific direction corresponding to the tilt angle and period pitch of this layer. Therefore, as shown in the figure, the extraordinary ray changes its optical path after passing through the hologram element 521, corresponding to the layer structure formed inside the element.

 In other words, by having a structure having a periodic structure in the thickness direction as described above, the Bragg diffraction condition is applied. This is because when light having a certain wavelength is incident on each layer forming the periodic structure, the light scattered in each layer strengthens the scattering component in a specific direction corresponding to the wavelength, the incident angle, and the pitch between the layers. A phenomenon occurs. This is called the Bragg diffraction condition, and such a condition results in a three-dimensional configuration compared to the conventional two-dimensional diffractive optical element, and the brazing (one direction) Converges light).

Therefore, compared with the conventional diffractive optical element, the diffraction efficiency is dramatically improved. Can be improved, and theoretically 100% efficiency is possible. In practice, 90% or more efficiency can be expected even when taking into account losses in the middle. On the other hand, in a two-dimensional diffractive optical element consisting of a binary, the diffracted wave is diffracted symmetrically to the higher order, including the 0th order, so that the diffraction efficiency in the first order is lower. The maximum is about 40%, which is a low value as a percentage of the total amount of light passing through the element.

 FIG. 19 shows the calculation results of the theoretical diffraction efficiency of the hologram element 52 1 in “Bell System Technology” (H. Kogelnik, (Bell Syst. Tech. J., 48, 1969, pp. 290-9 — 294 7) This is shown based on the analysis of)). The diffraction efficiency is the ratio of the amount of light diffracted in the primary direction to the total amount of incident light. Table 1 summarizes various parameters of the diffractive optical element.

 [Table 1] In Fig. 19, (a) shows the change in diffraction efficiency when the incident angle deviates from the Bragg angle, that is, the dependence of the diffraction efficiency on the incident angle, and (b) shows the design of the incident wavelength. It shows the change when the value deviates from the value, that is, the dependence of the diffraction efficiency on the incident wavelength.

The angle dependence in Fig. 19 (a) corresponds to the efficiency when the luminous flux incident on the holographic element 52 1 deviates from the parallel light (when the incident angle deviates from a predetermined angle). The dependence on the incident wavelength in Fig. 19 (b) corresponds to the study of the efficiency when illuminating with a white light source. As shown in the figure, by setting various parameters appropriately, it is expected that a theoretical diffraction efficiency of 1, that is, a high diffraction efficiency near 100% can be obtained. You. According to the figure, the characteristic is flat up to about ± 10 O nm with respect to wavelength, and high efficiency is expected even for white light. I can wait.

 Note that FIG. 18 shows a case where the optical axis of the optical medium 522 constituting the hologram element 521 is tilted by 90 ° between adjacent layers, and the refractive index difference is the largest. It is also possible to set the refractive index difference to an intermediate value between N e and N o by setting the angle arbitrarily. It is also possible to adjust the diffraction efficiency by selecting a refractive index distribution using this.

 It is also possible to divide the area of the hologram element 521 into several parts and shift the direction of diffraction in each part.

 In addition, R: red (0.65 μm), G: green, which constitute white light

(0.55 m), 8: Blue (0.45 m), each layer having a different periodic structure, angle, etc. is formed according to each center wavelength, and these layers are laminated. The hologram element 52 1 is configured as described above, or these structures are superimposed and recorded in the hologram element 52 1, so that the influence of chromatic dispersion or angle dependence is reduced. Such a configuration is also possible.

 Next, a method for manufacturing the hologram element 521 will be described. First, for example, I T0 is formed as a transparent conductive electrode on each of a pair of glass substrates.

 Next, these substrates are washed to remove dust adhering thereto, and then an alignment film made of a polymer, for example, a polyimide is applied by a spin coating method or the like, and heat treatment is performed. Then, an alignment film is formed on the substrate.

Thereafter, the alignment film is subjected to a rubbing treatment in a specific direction using a roller or the like, and then a seal is printed around one of the substrates, and the other substrate has a diameter of 5 μm to 20 μm. Disperse about m beads. These two Laminate the substrates so that the rubbing directions are paired with each other to form an empty cell.

 For example, a liquid crystal having a positive dielectric anisotropy is injected into the empty cell as an optical medium 522 having a refractive index anisotropy. It is also possible to use a liquid crystal having a negative dielectric anisotropy. More specifically, the above-mentioned liquid crystal contains, for example, a photopolymerizable liquid crystal monomer or a photo-crosslinkable liquid crystal polymer, and is irradiated with light having a wavelength in the ultraviolet region of about 360 nm. A material that has the property of hardening the liquid crystal and fixing the direction of the liquid crystal molecules is used. The above implantation can be performed at room temperature in an air atmosphere, but may be performed at a high temperature of about 40 ° C. to 60 ° C. or in a vacuum.

 The liquid crystal sample is completed by sealing the vicinity of the injection port and the deaeration port with a sealant in the cell after the liquid crystal is injected.

 The liquid crystal sample prepared as described above is exposed to interference fringes.

 First, the shutter for adjusting the exposure time is closed and the liquid crystal sample is arranged at a position where the optical system is manufactured (predetermined position of the exposure apparatus) in a state where there is no light irradiation, and the shutter is set. The shutter is opened for a predetermined time, for example, about 1 minute, and then closed, thereby performing exposure using interference fringes as a first exposure step.

As a light source for forming the interference fringes, for example, an A 、 (argon) laser having an irradiation intensity of about 50 mW to 100 mW, a wavelength of about 360 nm is used. Laser light can be used. This laser light is spread into a beam having a diameter of, for example, about 30 mm to 50 mm by a beam expander or the like, and then split in two directions by a beam splitter or the like, and the laser beam is split into two directions. Interference fringes through the optical path set by combining Form and irradiate the liquid crystal sample. The interference fringes are adjusted, for example, to about 1 m pitch at the position where the liquid crystal sample is arranged by adjusting the mirror and the like.

 By the above exposure, the liquid crystal in the liquid crystal sample is hardened by the liquid crystal in the region belonging to the bright area where the light intensity is high in the interference fringes formed by the interference of two laser beams, and the liquid crystal molecules are initially formed by the alignment film. The molecular axis is fixed in the direction of the orientation. That is, for example, when a liquid crystal having a positive dielectric anisotropy is used as described above, initially, the liquid crystal molecules are uniformly oriented in a direction parallel to the glass substrate, and the light fringe region of the interference fringe is formed. Now, this state will be saved. On the other hand, since the light intensity is lower in the dark area of the interference fringes than in the bright area, the liquid crystal molecules hardly harden in the first exposure step.

 Next, as a second exposure step, first, about 5 (V / m) was applied between the IT0 electrodes as transparent conductive electrodes formed inside the two glass substrates of the liquid crystal sample. Apply an AC electric field. Due to the application of the electric field, the uncured liquid crystal molecules in the dark areas of the interference fringes are tilted in a direction perpendicular to the glass substrate. Since the angle of inclination at this time is proportional to the applied electric field, a desired inclination angle, that is, a difference in refractive index can be given by adjusting the magnitude of the electric field.

 In the state where the voltage is applied as described above, for example, by blocking one of the laser beams split by beam splitting, a light having a uniform intensity distribution in which no interference fringes are formed. Is irradiated on the entire surface of the liquid crystal sample for, for example, about 5 minutes to completely cure the entire uncured dark area.

By performing the first exposure step and the second exposure step as described above, a hologram element 52 1 having a structure as shown in FIG. 18 is manufactured. You.

 In this case, a cell was fabricated using a glass substrate on which a transparent electrode such as ITO was formed, and the direction of liquid crystal molecules was changed from the initial position by applying an electric field in the second exposure step. We explained the case where we made it. As another method, it is possible to produce a hologram element 521 by performing a second exposure step by changing the direction of liquid crystal molecules by applying a magnetic field without using a transparent electrode. It is.

 Further, a method is also conceivable in which the direction of polarization of the irradiating Ar laser is set to be different, for example, by 90 ° between the first exposure step and the second exposure step, and exposure is performed. When a polymer film such as an alignment film is irradiated with linearly polarized light as a light source, the main chain (or side chain) of the randomly oriented polymer is oriented in the polarization direction. Molecules mainly absorb light to cause a photoreaction, and the film exhibits optical anisotropy. In a polymer material, the photoreaction process (photoisomerization, photopolymerization, photodecomposition) of the polymer can be controlled by the polarization direction of the irradiated light and the angle formed by the polymer.

 Therefore, by controlling the polarization direction of the light in the ultraviolet region constituting the interference fringes, the initial alignment state of the liquid crystal can be set and the movement of the liquid crystal molecules in the first and second exposure steps can be controlled. It is also possible to perform

 The diffraction efficiency of the device fabricated as described above was measured using a He-Ne laser while changing the incident polarization direction.The transmittance for ordinary light was around 98%. Yes, it had a high transmittance. In addition, the diffraction efficiency in the primary direction for extraordinary rays was about 90%, and good results were obtained. Therefore, it was confirmed that the diffractive optical element manufactured here had high polarization separation characteristics and diffraction efficiency.

Optical media having refractive index anisotropy include, in addition to liquid crystal, O and Bed acid _{Lithium, KD 2 P 0 4, -} ? B a B 2 0 4, this enables even der using uniaxial crystal having a PLZT of which electro-optic effect or the like is, also, KT i PO Similar effects can be obtained by using media having various refractive index anisotropies including biaxial optical crystals such as ₄ .

 (Embodiment B 2 — 2)

 Another example of the polarization splitting element configured using the hologram element will be described.

 As shown in FIG. 20, this polarization separation element 530 is provided on the surface of the total reflection mirror 531, as shown in the embodiment B1 or the embodiment B2-1. A similar hologram element 532 is provided. Here, when the hologram element of Embodiment B1 is used, the hologram element is used in a state where a predetermined voltage is applied between IT0.

 The total reflection mirror 531 and the hologram element 532 are normal to the optical axis of the reflector 5334 that reflects the light from the lamp 533 of the light source. Are arranged at an angle of 45 °.

 In the hologram element 532 described above, light having a polarization direction in a direction perpendicular to the plane of the drawing (referred to as S-polarized light) becomes an ordinary ray and light having a polarization direction in a direction parallel to the plane of the drawing. (Referred to as P-polarized light) are arranged so as to be extraordinary rays. Also, this hologram element 5 32

An extraordinary ray incident at an incident angle of 5 ° is set to be diffracted and emitted so as to have an emission angle slightly larger than 45 °.

With such a configuration, the S-polarized light, which is an ordinary ray with respect to the hologram element 532, is emitted from the element as described in each of Embodiments B. It is not affected by the refractive index distribution of the periodic structure, and exhibits the same characteristics as when passing through a medium having an isotropic and uniform refractive index. Soy sauce In addition, the S-polarized light passes through the hologram element 532 as it is, is reflected by the total reflection mirror 531, passes through the hologram element 532 again, and exits. That is, the traveling direction of the S-polarized light is bent 90 ° by the total reflection mirror 531, and the S-polarized light is emitted.

 On the other hand, the P-polarized light, which is an extraordinary ray with respect to the hologram element 532, is modulated by the refractive index distribution of the periodic structure formed in the hologram element 532, and is diffracted. Thus, the light exits at an exit angle slightly larger than 45 °.

 Therefore, the light emitted from the lamp 533 via the reflector 534 travels as S-polarized light and P-polarized light by the polarization separation element 530. It can be separated into outgoing light beams with slightly different directions. (Embodiment B3-11-1)

 An example of a polarization conversion element configured by using the polarization beam splitter of Embodiment B22 will be described. This polarization conversion element is for outputting light with a random polarization direction from a light source to polarized light of a predetermined direction, and is used, for example, in a polarization illuminating device such as a polarization type liquid crystal display element. FIG. 21 is an explanatory diagram showing a configuration of a polarized light illuminating device including a polarization conversion element 540.

 As the lamp 533, a fluorescent lamp, a xenon lamp, a metal halide lamp, a mercury lamp, an LED, a FED, a laser beam, an inorganic or organic EL element, or the like is used. The light from the lamp 533 is emitted by the reflector 534 as substantially parallel light. The substantially parallel light enters the polarization beam splitter 530, and is separated so that the traveling directions of the S-polarized light and the P-polarized light are slightly different as described in the embodiment B2-2. Then, the light is emitted from the polarization separation element 530.

The S-polarized light and P-polarized light emitted from the polarization separation element 530 are First, the first lens group (the first fly-eye lens) 542 of the integral lens 541, which is incident on each of the lenses 5442a of the first lens group, corresponds to the incident angle of each lens. Then, a second lens group (second fly-eye lens) that forms a pair with each lens is connected to a predetermined area different from each other in each of the lenses of the 543 lens. You.

 The predetermined region in which the S-polarized light and the P-polarized light are collected is set to, for example, a region that roughly divides each lens 543a, and the P-polarized light is collected. A retardation plate 544, which is a half-wave plate, is periodically provided on the rear surface side (in the light traveling direction) of each lens 543a in the region. Therefore, the S-polarized light that has entered the second lens group 543 exits as it is as S-polarized light, while the P-polarized light has a polarization direction of 9 through the phase plate 544. Rotated by 0 °, converted into S-polarized light and emitted. That is, any polarized light is emitted while being aligned with S-polarized light.

 This s-polarized light is divided into a field lens 54 5 and a focusing lens 54

6 through the image display element (light valve) as a substantially parallel light beam.

It is incident on 47 and used for image display.

 Comparing the amount of light incident on the image display element 547 with and without using the hologram element 532 and the phase difference plate 5444 as described above, When polarization conversion is performed by the program element 532 and the phase difference plate 544, the light use efficiency is improved by about 1.2 to 1.6 times, and the above-described hologram element 532 is used. It was confirmed that the function of the polarization conversion element 540 was excellent.

 (Embodiment B 3-2)

 The polarization beam splitting element described in the embodiment B3-1 is used as an integral element.

—Provided in the light path between the first and second lenses that make up the evening An example of a polarization conversion element that aligns the polarization directions by being applied will be described. In the embodiment B and the like, components having the same functions as those in the embodiment B31 and the like are denoted by the same reference numerals as appropriate, and detailed description is omitted.

 FIG. 22 is an explanatory diagram showing the configuration of the polarized light illuminating device including the polarization conversion element 545.

 The substantially parallel light from the reflector 534 is incident on the polarization separation element 530 via the first lens group 542 constituting the integrator 541. ing. The luminous flux incident on the polarization splitter 530 is split so that the traveling directions of the S-polarized light and the P-polarized light are slightly different as described in Embodiment B2-2, and the polarization splitter is The light exits from 5300.

 The S-polarized light and the P-polarized light emitted from the polarization splitter 530 are respectively the second lens group (second fly's eye lens) 543 that composes the integration 541. In each of the lenses 543a, the light is focused on a region where the retardation plate 544 is provided on the back surface side or a region where the retardation plate 544 is not provided. Thus, as in Embodiment B3-1, the S-polarized light is emitted as it is as the S-polarized light, while the P-polarized light is polarized through the retardation plate 544. The light is rotated 90 °, converted into S-polarized light, and emitted. That is, any polarized light is emitted while being aligned with S-polarized light. Even with the polarization conversion element 545 configured as described above, the light use efficiency can be improved as in the embodiment B3-1.

 (Embodiment B 3 — 3)

An example of another polarization conversion element using the same hologram element as that described in Embodiment B1 or Embodiment B2-1 will be described. FIG. 23 is an explanatory diagram showing a configuration of a polarized light illuminating device including a polarization conversion element 550. The polarization conversion element 550 of this polarization illuminating device is composed of a hologram element 551 and a total reflection mirror similar to those described in the embodiment B1 or the embodiment B2-1. A phase difference plate 551, which is a 波長 wavelength plate, is provided between the phase difference plate 31 and the phase difference plate 31.

 The light wave including the P-polarized light and the S-polarized light from the lamp 533 is incident on the hologram element 551, and the P-polarized light is diffracted by the diffractive optical element as described in Embodiment B1 and the like. The light is diffracted according to the refractive index distribution and the like, and the light is emitted with its course bent in the direction shown by the one-dot chain line in FIG.

On the other hand, the S-polarized light passes through the hologram element 551, as it is, is reflected by the total reflection mirror 531 through the phase difference plate 552, and passes through the phase plate 552 again. In the process, the polarization direction changes by 90 ° with respect to the incident light, and the light enters the hologram element 551 as P-polarized light. The direction of incidence at this time is determined by the arrangement of the total reflection mirror 531 and the reflector 5334, which is formed inside the hologram element 551. The hologram element 551 transmits the incident light without reflecting it so that the condition is deviated from the Bragg diffraction condition for the periodic structure. That is, as described in FIG. 19 (a), the angle dependence of the diffraction efficiency is described. When the angle of incidence on the hologram element deviates from the predetermined angle to some extent, the efficiency becomes almost zero, and the diffraction effect is reduced. In some cases, only the light is transmitted without being generated, and the above-described predetermined angle can be set according to the forming conditions of the diffractive optical element. Therefore, the light beam reflected by the total reflection mirror 531 and converted into P-polarized light by the phase difference plate 552 passes through the hologram element 551 without being diffracted. You can do it. It should be noted that the light is diffracted and almost coincides with the propagation direction of the P-polarized light directly diffracted by the hologram element 551. It is also possible to make it happen.

 As described above, the lightwave from the lamp 533 is diffracted into P-polarized light by the hologram element 551, and the S-polarized light transmitted through the hologram element 551 is totally reflected by the mirror. After being converted into P-polarized light by 31 and the phase difference plate 552, the light is transmitted through the hologram element 551 and emitted to obtain a substantially parallel light beam with the same polarization direction. be able to.

 When the light use efficiency of the polarized light illuminating device was determined in the same manner as in Embodiment B3-1, the light illuminating device was compared with the case where the hologram element 55 1 and the phase difference plate 5 52 were not used. It was possible to obtain a light use efficiency of about 2 to 1.5 times.

 Further, according to the above-described configuration, polarization conversion can be performed only by a simple laminated structure of the hologram element, the phase difference plate 552, and the total reflection mirror 531. Therefore, it can be easily combined with an optical system such as an integrator and can be used for a wide range of optical system devices. In particular, a device equipped with a mirror that turns back in advance, such as a color image display device that performs color separation and color synthesis with, for example, two dichroic prisms In the case of application to a mirror, it is only necessary to use a mirror provided with a hologram element instead of the mirror, so that the light use efficiency can be improved without increasing the number of parts. I can do it.

 (Embodiment B 3 — 4)

 An example of another polarization conversion element using the same hologram element as that described in the embodiment B1 or the embodiment B2-1 will be described.

The polarization as shown in FIG. 24 is obtained by using the same two hologram elements 56 1 and 56 2 as shown in the embodiment B 1 or the embodiment B 21. A polarized light illumination device including the conversion element 560 was constructed. The luminous flux containing the P-polarized light and the S-polarized light from the lamp 533 enters the hologram element 561 via the reflector 534, and the S-polarized light is It is transmitted as almost parallel light. The P-polarized light is prayed by the hologram element 562 so that the propagation direction changes by approximately 90 ° according to the principle described in the embodiment B1 and the like.

 This light wave further enters the hologram element 562, and is similarly diffracted here, and the propagation direction is almost equal to the direction of the light beam reflected from the initial reflector 534. It is emitted so that it becomes dark. Thereafter, the light passes through a phase difference plate 563 which is a half-wave plate, is rotated by 90 °, and is emitted as an S-polarized light wave. That is, the light wave emitted from the lamp 533 and diffracted by the hologram element 561 is converted by the diffractive optical element 562 and the phase difference plate 563 into a hologram element 563. It is emitted as a substantially parallel light beam whose polarization direction is aligned with the light wave transmitted through 1.

 When the light wave recycling rate at the hologram element 562 of the above-described polarized light device was measured, the light flux from the hologram element 562 was the hologram element 5 62. A luminous flux converted to S-polarized light with an intensity ratio of about 90% of the luminous flux from 61 was obtained.

The advantage of using the hologram elements 561 and 562 as described above is that it is possible to arbitrarily set the separation angle when performing polarization separation. In other words, as usual, when the polarization beam splitter is combined with the total reflection mirror to perform polarization separation, in order to bend the propagation direction by 90 °, the reflection surface must be incident on the incident light. It must be tilted by 45 ° (corresponding to Θ in Fig. 24). Therefore, in the depth direction, a magnitude force ^s corresponding to the size and inclination of the reflection surface is required, and the constraint in the thickness direction becomes large in an apparatus using the polarization illuminating apparatus. On the other hand, when the hologram element is used as described above, the polarization separation angle can be set arbitrarily by the refractive index distribution formed inside, so that the diffractive optical element is used to make the diffractive optical element incident light. 45 for a plane perpendicular to the plane. It is possible to set S in Fig. 24 at a small angle of 45 ° or less, and to make the hologram elements parallel to each other. By arranging them in pairs, a polarization conversion optical system can be configured, so that the size in the depth direction can be significantly reduced. This makes it possible to use a thin system, and when combined with an illumination optical system, such as an integrated optical system, into which polarized light that has been subjected to polarization conversion is incident, a compact system (such as an illumination device or an image display device) can be used. Etc.) can be realized.

 (Embodiment B 3-5)

 A hologram element similar to that shown in the above-described Embodiment B1 or Embodiment B21-11 is used, and an output from an integer having a first lens group and a second lens group is used. An example of a polarization conversion element that aligns the polarization direction of the light to be performed will be described.

 As shown in FIG. 25, a plurality of sets are arranged as pairs of the hologram elements 57 1 and 57 2 similar to those shown in the embodiment B 1 or the embodiment B 2-1. Thus, a polarization illuminating device including the polarization conversion element 570 was constructed. Note that FIG. 1 shows an example in which a projection type image display device is configured by combining an image display element 577, a projection lens 578, and the like.

The light wave including the P-polarized light and the S-polarized light transmitted from the first lens group (not shown) in the integrator is incident on the second lens group 571 and the light beam is narrowed down. The light enters the hologram element 572 corresponding to each lens 571a of the group 571. Here, the S-polarized light is transmitted as it is, and the P-polarized light is diffracted and enters the adjacent hologram element 572. Then, the light is further diffracted and propagates in a direction substantially equal to that of the above-mentioned S-polarized light, and the polarization direction is changed by a retardation plate 574 which is a half-wave plate. The light is rotated 90 °, converted into S-polarized light, and emitted.

 These processes are performed for each set of a plurality of holographic elements 572, 573 and a retardation plate 574, which are arranged in a plurality, and the light wave passing through the second lens group 571 is polarized. The light is emitted in the same direction. In addition, since the luminous flux is narrowed and used in combination with the integration, it is possible to perform polarization conversion without greatly changing the width of the luminous flux from the light source.

 The luminous flux whose polarization direction has been aligned as described above is converted into a parallel luminous flux by the field lens 575 and the condensing lens 576, and the polarization type liquid crystal display element is used. After being incident on an image display element 5778 such as the like, and subjected to luminance modulation for each pixel, the image is enlarged and projected on a screen 5779 by a projection lens 579.

 The brightness on the screen was compared between the case where the polarization conversion was performed by the polarization conversion element 570 as described above and the case where the polarization conversion was not performed, and 30% when the polarization conversion was performed. Brightness has increased, and a bright image has been obtained.

 (Embodiment B 3 — 6)

 An example of another polarization conversion element using the same hologram element as that described in the embodiment B1 or the embodiment B21 will be described.

As shown in FIG. 26, a pair of polarization conversion elements 560 similar to the embodiment B3-4 is targeted for the optical axis of the reflector 534. And the polarization conversion element 590 may be configured. With such a configuration, since the reflector 534 is arranged at, for example, the center in the width direction of the polarized light illuminating device, a uniform space is formed on both sides. This facilitates the arrangement of other components and the like in the device to which the polarized light illumination device is applied.

 (Embodiment B 4 — 1)

 An example in which a projection type image display device configured using the polarization beam splitter 510 of the embodiment B2-1 (FIG. 13) will be described. As the hologram element constituting the polarization splitting element 5110, the one shown in the embodiment B1 or the embodiment B2-1 (FIGS. 10 and 18, etc.) is applied. be able to. Here, when the hologram element of Embodiment B1 is used, the operation is performed in a state where a predetermined voltage is applied between IT0.

 As shown in FIG. 27, the projection-type image display device 600 is composed of a lamp 533, a reflector 534, a polarization separation element 510, and an integrated circuit. A polarizing illuminator 6001 is provided, and the output light beam from the lamp 533 is reflected by the reflector 533, and the reflected output light beam /? Is reflected by the polarization separation element 510 and the integration device. For example, the light is incident on an image display element 547 such as a transmissive liquid crystal panel through the projector 51, and the luminous flux whose luminance has been modulated is screened by a projection lens 602 (not shown). ) The image is displayed by enlarging and projecting it.

 Next, a description will be given of the polarization separation element 510 and the integration element used in the projection type image display device 600. As described in Embodiment B 2-1, the polarization separation element 5 10 used in the present invention includes the first hologram element 5 11 1 and the second hologram element 5 12 It transmits P-polarized light straight through (at an output angle of 0 °) and transmits S-polarized light at an output angle of approximately 17 °.

Also, the first minute lenses constituting the first lens group (first fly-eye lens) 542 are respectively the second lens group (second fly-eye lens). An image of the lamp is formed on each of the second lenses composing 5 4 3. At this time, the P-polarized light and the S-polarized light (5 are imaged at different positions. For example, in the portion where the S-polarized light (5) is imaged, the half-wavelength as the polarization plane rotating means is provided. A retardation plate 544, which is a plate (e / 2 plate), is provided, and S-polarized light (5 is substantially converted into P-polarized light and transmitted through the retardation plate 544) is output. Which polarization component of the P-polarized light and the S-polarized light 5 to rotate the polarization plane is determined by the polarization direction of the polarizing plate included in the image display element 547.

 The second lens group 543 forms an image of each of the minute lenses constituting the first lens group 542 over almost the entire display image area of the image display element 547. Thereby, the uniformity of the brightness of the displayed image is ensured.

 By configuring the polarized light illuminator 601 as described above, it is possible to efficiently convert non-polarized light output from the lamp 533 into P-polarized light, and achieve high projection. Efficiency can be realized. Further, the polarization separation element 510 as described above can be easily manufactured and can be configured at low cost. Further, since the polarization separation element 510 has a small dimension in the optical axis direction, it is possible to easily configure a compact polarization separation element having high separation efficiency. In addition, by using the above-described polarization splitting element, a projection-type image display device having high light use efficiency can be easily realized.

 If the positions of the lamps 53 3 and the reflectors 53 4 are changed, the polarization as shown in the embodiment B 3 — 1 to 3 — 3 (FIGS. 21 to 23) can be obtained. A conversion element 530 or the like can also be used.

In addition, as the lamp 533, a metal halide lamp, a nitrogen lamp, a xenon lamp, an ultrahigh-pressure mercury lamp, or the like may be used. However, it is preferable to use a light emitting region having a small size.

 (Embodiment B 4 — 2)

 An example of a so-called three-panel projection image display device that includes three transmissive image display elements and optical elements for color separation and color synthesis and that can display a single color image will be described.

 This image display device is provided with a color synthesis system element 620 shown in FIG. 28 (b) below the color separation system element 610 shown in FIG. 28 (a).

 The color separation element 6110 is composed of a polarization illuminating device 611 including a polarization conversion element similar to that described in the embodiment B4-1, and a dichroic prism 611. , And total reflection mirrors 612 to 614, and the light output from the polarized light illuminator 601 is converted to each wavelength of R (red), G (green), and B (blue). It breaks down into light. On the other hand, the color synthesizing elements 62 0 are total reflection mirrors 62 1 to 62 3, image display elements 62 4 to 62 6, and a dichroic prism 62 5. , And a projection lens 628, and color synthesis is performed after light of each wavelength guided from the color separation element 610 passes through the image display elements 624 to 626. The image is projected on the screen 629 by the projection lens 628.

In this image display device, the substantially parallel light beam output from the lamp 533 via the reflector 534 is polarized similarly to the embodiment B4-1 described above. After the polarization direction is aligned by the separation element 510 and the integration circuit 541 and the uniformity of the luminous flux in the plane is maintained, the die Into the mechanism 6 1 1. This dichroic prism 611 is a filter of wavelengths in each band. The white light from the polarized light illuminator 601 corresponds to the wavelength filter, and the light corresponding to each of the three primary colors R, G, and B corresponds to the wavelength filter. The light is emitted in the directions indicated by arrows in the figure. Here, the dichroic prism 611 has the same function as the case where a two-piece dichroic mirror is used. In addition, since color separation can be performed without using a large space, a compact display device can be configured.

 The light of each color emitted from the dichroic prism 611 is reflected by the total reflection mirrors 612 to 624, and is reflected by the lower color synthesis element 620. Be guided. The light of each color guided from the color separation system element 6 10 to the color combining adjective 6 20 has a traveling direction of approximately 90 ° through the total reflection mirror 6 2 1-6 2 3 The light is changed and reflected, and after being subjected to luminance modulation by the transmission type image display elements 624 to 626 corresponding to the light of each color, the light is incident on the dichroic prism 627. The dichroic prism 627 has a function opposite to that of the dichroic prism 611, and the light incident on the dichroic prism split into R, G, and B light, respectively. The synthesized light is emitted in the direction of the projection lens 628. The light emitted from the dichroic prism 627 is projected by a projection lens 628 onto a screen 629 and displayed as an enlarged image.

 By providing a polarization conversion element for aligning the polarization direction of the light beam output from the reflector 534 as described above, the light use efficiency is improved, and a bright image is displayed. O Image display device that can be configured o

As described above, an image display device that displays a blank image is polarized. When a conversion element or the like is applied, a holographic element can be manufactured by performing multiple exposures using light interference fringes of red, green, and blue light, or diffracting light of each color. On the other hand, a structure in which hologram elements optimized for each other are laminated may be used.

 Also, instead of the polarization splitting element 510 and the phase difference plate 544, a polarization conversion element 5 as shown in Embodiment B 3 — 4 to 3 — 6 (FIGS. 24 to 26). Even when 60 or the like is used, a high light use efficiency can be obtained similarly.

 The same effect can be obtained even if the above-described polarization conversion element 550 and the like are arranged between the integrator 541 and the dichroic prism 611. I can do it. In addition, the polarization conversion element 550 or the like is irradiated between the dike mouth prism 611 and the image display elements 624 to 626, that is, the light of each color after color separation. It is also possible to provide three polarization conversion elements (and an integer) corresponding to the above. In this case, a polarization conversion element is provided separately for each color light, so it is optimized as a hologram element so that the influence of chromatic dispersion can be reduced according to the wavelength of each color. , That is, a periodic structure corresponding to each wavelength is formed? >> can be used, and the light use efficiency can be further improved. Similarly, the integrator may be provided after the dike prism 611.

 If the positions of the lamps 53 3 and the reflectors 53 4 are changed, the polarization as shown in the embodiment B 3 — 1 to 3 — 3 (FIGS. 21 to 23) can be obtained. A conversion element 540 or the like can be used.

In addition, even when a reflector is provided in the same arrangement as in FIG. 28, the polarization conversion element is replaced by the dichroic prism 61 and the image display element 62. In the case where three polarization conversion elements (and integers) corresponding to light of each color after color separation are provided between 4 and 626, a polarization conversion element as described above is used. In this case, a total reflection mirror 612 for guiding light of each color from the color separation system element 610 to the color combining element 620 is used as the whole of the polarization conversion element. It can also be used as a reflection mirror 5 3 1. In addition, as described above, a hologram element that is adapted to the wavelength of each color can be used.

 Note that when a polarization conversion element is provided in each path after color separation, the brightness on the screen of an image that is completely combined is higher than when no polarization conversion element is used. As a result, it was possible to increase by about 30%. This was substantially the same for the transmission type as described above and the reflection type described later. As described above, the polarization conversion using the diffractive optical element is also effective for the color display.

 In the configuration shown in FIG. 23, it is also possible to use a means for changing the thickness of the phase plate in the plane in order to correct the polarization characteristics depending on the incident angle of the phase plate. .

 (Embodiment B 4 — 3)

 An example of a three-panel projection-type image display device capable of displaying a color image by using a reflection-type image display device with a configuration similar to that of Embodiment B4-2 will be described.

 This image display device is provided with a color composition system element 630 shown in FIG. 29 (b) below the color separation system element 610 shown in FIG. 29 (a).

As the color separation element 6 10, the same one as that described in the embodiment B4-2 is used. On the other hand, the color composition element 6 Form B 4 — Compared to 2,

The point that polarizing beam splitters 631 to 633 are provided instead of the total reflection mirror 621, and the transmission type image display element 62-4-626 Instead, a reflective image display element 634-636 is provided.

 The polarizing beam splitters 631 to 633 reflect only light in a predetermined polarization direction, but the light actually guided from the color separation element 610 is subjected to polarization conversion. Since the light is polarized in the same direction by the elements, almost all of the light is reflected and is incident on the image display element 634-636. The light incident on the image display elements 634 to 6336 is reflected after being modulated in the direction of polarization according to the display image of each color, and re-enters the polarization beam splitters 631 to 633, where a predetermined light is emitted. Since only the light in the polarization direction is transmitted, the modulation in the polarization direction is converted into luminance modulation and visualized. After that, the color is synthesized by the die shadow mirror 637 in the same manner as in the embodiment B4-2, and the image is formed on the screen 629 by the projection lens 628. Is projected.

 Even in the reflection type image display device as described above, the polarization conversion device for aligning the polarization direction of the light beam output from the reflection device 534 is provided. An image display device capable of displaying a bright image with improved utilization efficiency can be configured.

 Also, in this image display device, various modifications as described in the embodiment B4-2 are similarly possible.

 (Embodiment B5-1)

 An example of an image display device including a hologram element will be described.

As shown in FIG. 30, the image display device is provided with holographic elements 720 and 703, which are diffractive optical elements, on both sides of a liquid crystal element 701. On the back side thereof, a light source 704 having a lamp 704a and a reflector 704b is provided.

 Here, in the following description, light having a polarization direction in a direction parallel to the plane of the drawing is referred to as P-polarized light, and light having a polarization direction in a direction perpendicular to the plane of the drawing is referred to as S-polarized light.

 The lamp 704a of the light source 704 is, for example, a fluorescent lamp, a xenon lamp, a metal halide lamp, a mercury lamp, an LED, a FED, a laser beam, an inorganic or organic EL element. Etc. can be used. The light emitted from the lamp 704a is emitted as substantially parallel light by the reflector 704b. This light source light includes P-polarized light and S-polarized light.

As the liquid crystal element 701, for example, a twisted nematic liquid crystal in which directions of liquid crystal molecules are twisted by 90 ° on a light incident surface side and a light incident surface side is used. . The liquid crystal element 701 is provided with a transparent electrode (not shown) formed in a predetermined pattern, so that a voltage can be applied to the liquid crystal for each pixel. ing. At a pixel (ON) where a predetermined sufficient voltage (a voltage that can completely switch the liquid crystal) is applied to the liquid crystal, the twist of the liquid crystal molecules is released and the light incident surface is released. The liquid crystal molecules are in a state of isotropic standing (home-opening pick). For this reason, when P-polarized light enters the pixel, the polarization direction is not modulated and passes through the liquid crystal element 70 1 while maintaining its polarization state. On the other hand, in the pixel where no voltage is applied to the liquid crystal (OFF), the liquid crystal molecules are twisted by 90 ° in the thickness direction from the entrance surface to the exit surface. . Therefore, when the P-polarized light enters the pixel, the P-polarized light is twisted by the liquid crystal while passing through the liquid crystal element 701 from the entrance surface to the exit surface. Due to the twist nematic effect, the plane of polarization is rotated 90 °. Therefore, after passing through the OFF pixel, the light is emitted as S-polarized light.

 Further, as the hologram elements 72 and 703, for example, the same hologram elements as those described in the embodiment B1 or the embodiment B2-1 are used. Here, when the hologram element of Embodiment B1 is used, the hologram element is used in a state where a predetermined voltage is applied between IT0. As described above, the holographic elements 720 and 703 have different diffraction effects depending on the polarization direction, and have a property of exhibiting a high diffraction efficiency in one predetermined direction. are doing.

 Specifically, for example, among the light incident on the hologram elements 720 and 703, the s-polarized light acts as an extraordinary light component, so that the hologram elements 720 and 703 The light is modulated by the refractive index distribution of the periodic structure formed therein, and is emitted with its traveling direction bent upward in FIG. On the other hand, since the P-polarized light acts as an ordinary light component on the hologram elements 720 and 703, the refractive index distribution composed of the periodic structure of the hologram elements 720 and 703 is obtained. It behaves in the same way as when passing through a medium with an isotropic and uniform refractive index, without being affected by the light. For this reason, the P-polarized light passes through the hologram elements 720 and 703 as it is.

Therefore, when light including P-polarized light and S-polarized light from the light source 704 enters the hologram element 72, the S-polarized light is diffracted as described above, and The light is hardly incident on 1, and only the P-polarized light passes through the hologram element 702 and is incident on the liquid crystal element 701. As described above, the P-polarized light that has entered the liquid crystal element 701, as described above, is emitted as P-polarized light at the ON pixel, while being converted to S-polarized light at the OFF pixel and emitted. That is, the light emitted from the liquid crystal element 70 1 The polarized light changes depending on the ON / OFF status of the pixel.

When the light emitted from the liquid crystal element 701 enters the hologram element 703, as in the hologram element 702, the S-polarized light is diffracted, and only the P-polarized light remains unchanged. Go straight. That is, the direction in which the light that has passed through each pixel of the liquid crystal element 701 exits from the hologram element 703 differs depending on whether the pixel is ON or OFF. Therefore, from an observer who views the image display device from almost the normal direction of the display surface, the light that has passed through the 0FF pixel is emitted to the outside of the field of view by the diffraction action of the holographic element 703. While passing through the 0N pixel, the light goes straight through the hologram element 703 and enters the observer's field of view, where it is visually recognized as a ^1- turn light. .

Next, an example of an actually manufactured image display device will be described. In this image display device, the light source 704 uses a fluorescent lamp that passes through a green filter, and emits light having a wavelength of about 0.55 m. I was afraid. As the liquid crystal element 701, a liquid crystal element having a resolution of about 3 inches of VGA (640 × 480) was used. When an image signal is input to this and observed from almost the normal direction (front) of the display screen, an image corresponding to the image signal input to the liquid crystal element 701 can be correctly viewed. And came out. The contrast was about 10: 1. When the observation position was moved in the direction in which the S-polarized light having passed through the hologram element 703 was diffracted (upward in FIG. 30), an image in which the brightness was inverted from the previous image was obtained. Was seen. As described above, the refractive index distribution type hologram elements 720 and 703 composed of the optical medium having the refractive index anisotropy are configured by combining the liquid crystal element 701. Therefore, the light that is incident on the OFF pixels is not blocked (absorbed) but emitted out of the observer's field of view, thereby displaying the image. Thus, an image display device with good visibility can be manufactured. However, unlike the case where a polarizing plate is used, heat generation due to light absorption does not occur.

 By controlling the voltage applied to each pixel, the polarization direction of the light passing through the liquid crystal according to the voltage is changed to an intermediate state between the P-polarized light and the S-polarized light, that is, elliptically polarized light. It can be set as follows. At this time, the light incident on the hologram element 703 is divided into a component that goes straight and a component that is diffracted according to the voltage applied to each pixel, so that a halftone display is also possible.

 Further, in the above example, the liquid crystal element 70 1 has been described as a diagonal nematic type, but the action of modulating the polarization direction of incident light is described. Any type may be used as long as it has Further, a super-state-stated nematic (STN) liquid crystal having a twist angle of 90 ° or more can also be used. In addition, the liquid crystal molecules are homogeneously aligned in the thickness direction, and have a home-port pick-up alignment when an electric field is applied, or a homeotropic alignment. A similar effect can be obtained by using a liquid crystal in a VA (Vertical Aligne) mode such as one that changes from a liquid crystal alignment to a homogeneous alignment.

 Furthermore, it is also possible to use a ferroelectric liquid crystal or an antiferroelectric liquid crystal in which the direction of arrangement of liquid crystal molecules differs depending on the polarity of the electric field.

The liquid crystal element 701 as described above is similar to a liquid crystal panel that is usually used as a liquid crystal display. Therefore, the image display device as described above can be configured simply by replacing the front and rear polarizers used in the liquid crystal element with the hologram elements 720 and 703 of the present invention. And drive systems can be applied as they are. Therefore, it is very versatile.

 (Embodiment B 5 — 2)

 An image display device as shown in FIG. 31 was configured using the same hologram elements 720 and 703 as those in Embodiment B5-1. In other words, the light source 704 is arranged near the lower side of the holographic element 702, so that a so-called side light for irradiating light from an oblique side is adopted. As the light source 704, a light source provided with a green filter on a fluorescent lamp as in Embodiment B5-1 was used. Other configurations are the same as those in the embodiment B5-1.

 In this image display device, of the light emitted from the light source 704, the P-polarized light passes through the hologram element 702 as it is and does not enter the liquid crystal element 701. Also, the S-polarized light is bent by the hologram element 72 2 at an angle of about 90 ° with respect to the display screen, and enters the liquid crystal element 70 1. Light passing through the liquid crystal element 701 enters another holographic element 703 whose polarization direction is modulated in accordance with a signal applied to the pixel. Here, the S-polarized light is diffracted upward in the same figure and emitted out of the viewing range of the observer. The P-polarized light passes through the hologram element 703 as it is, and is visually recognized by an observer. When the hologram element was observed from the observer's position from the normal direction of the holographic element 703-direction display screen, an image corresponding to the input image signal was correctly viewed. It was also possible to observe the external scenery from the position near the observer through the holographic elements 72,703. As described above, the image display device configured as described above can switch the image display and the external scenery at the same time or to visually recognize the scene. It can be used as a display on the screen.

(Embodiment B5-3) An image display device as shown in FIG. 32 was constructed using one hologram element 702 similar to that of the embodiment B5-1. That is, the image display device has no light source inside, and is configured to display an image using external light such as natural light or indoor light. Further, the same liquid crystal element 700 as that of Embodiment B1 was used.

 The display principle of the image display device will be described below.

 First, when external light 710 including P-polarized light and S-polarized light enters the hologram element 702, the P-polarized light component is not modulated by the hologram element 702. It is transmitted as it is and hardly enters the liquid crystal element 701. On the other hand, the S-polarized light is diffracted by the hologram element 70 2, and almost all light enters the liquid crystal element 70 1. The light that has entered the liquid crystal element 71 1 passes through the area of each pixel and is reflected by the mirror 71 1. The mirror 711 can be made of a metal or a dielectric multilayer film. For the actual production, a glass substrate with aluminum evaporated was used.

The light reflected by the mirror 711 passes through the area of each pixel of the liquid crystal element 701 again, and the polarization direction is modulated according to the voltage applied to each pixel, and the hologram The light enters the element 70 2. The S-polarized light that has entered the hologram element 702 is diffracted upward in the same figure and is emitted out of the observer's field of view. In addition, the P-polarized light passes through the hologram element 702 as it is, so that it can be visually recognized by an observer. In response to the signal voltage applied to each pixel of the liquid crystal element, The image is viewed. When the reflection-type image display device using the above-mentioned mirror, which was actually manufactured, was observed with room light illumination, an image composed of light and dark patterns was visually recognized. The contrast was about 10: 1. Degradation of image quality due to color bleeding, etc. using a white light source that is indoor light There wasn't much. This is because the S-polarized light diffracted by the hologram element 703 on the return path has a different diffraction direction depending on the wavelength, but if the diffraction angle is set to be larger than the viewing area of the observer, However, it is considered that the influence of the diffraction angle depending on the wavelength is hardly a problem because it is outside the recognition area.

 Therefore, it is possible to clearly recognize an image in the reflection-type image display device using external light configured as described above, and furthermore, since the internal backlight is not required, the image is low. Suitable for power consumption and small size dani.

 (Embodiment B 5 — 4)

 As shown in FIG. 33, an image display device of a combined type using external light and an internal light source configured using the same hologram elements 720 and 703 as in Embodiment B5-1. Will be described.

In this image display device, the hologram elements 720 and 703 are the same as those shown in the embodiment B5-1, but the hologram element 720 is the same as that in the embodiment B5-1. Compared to B 5 — 1, it is rotated 90 ° in the same plane. Therefore, the hologram element 72 does not exhibit a diffractive effect on the S-polarized light, but has a diffractive effect on the P-polarized light. That is, the hologram elements 72 and 703 are configured such that the polarization direction dependence on the P-polarized light and the S-polarized light is reversed. The same function can also be provided by performing the alignment process in the hologram element shown in FIG. 18 so that the initial alignment direction of the homogenous liquid crystal differs by 90 °. Can be done. In other words, it is possible to determine which polarized light has a diffractive effect depending on how the alignment direction of the liquid crystal molecules is set with respect to the incident light. You. The liquid crystal element 700 is the same as that used in Embodiment B5-1. The mirror 711 is formed by vapor deposition of aluminum in the same manner as in Embodiment B5-3. The light source 704 was a fluorescent lamp and was used as a white light source.

 Here, in FIG. 33, solid arrows indicate propagation of external light, and dashed-dotted arrows indicate propagation of light from the light source 704.

 Hereinafter, a display operation using light from the light source 704 will be described first. Light including P-polarized light and S-polarized light from a light source 704 arranged diagonally to the side of the hologram element 720 as a side light is supplied to the hologram element 720. As a result, the S-polarized light is transmitted without being affected by diffraction, and the P-polarized light is bent by diffraction into a direction of approximately 90 ° with respect to the display screen, and the liquid crystal element 7 is bent. It is incident on 0 1.

 The P-polarized light that has entered the liquid crystal element 701 is modulated by each pixel of the liquid crystal element, and the polarization direction changes. Accordingly, the traveling direction due to the action of the hologram element 703 changes. As a result, the observer can visually recognize the image information corresponding to the input image signal.

Next, a display operation using the external light 7 10 will be described. Of the external light 710, the P-polarized light is transmitted without being modulated by the hologram element 703, and does not enter the liquid crystal element 701. The traveling direction of the S-polarized light is bent by the diffraction action of the diffraction optical element, and is substantially incident on the liquid crystal element 701. The S-polarized light that has passed through each pixel of the liquid crystal element 701 is not affected by the diffraction effect on the hologram element 702, so it is transmitted as it is and reflected by the mirror 711. After passing through the hologram element 702 again, the light is incident on each pixel of the liquid crystal element 701, and the polarization direction is modulated for each pixel to be incident on the hologram element 703. The S-polarized light passing through the ON pixel is diffracted by the hologram element 703 and It is emitted out of the viewing zone. In addition, the P-polarized light that has passed through the OFF pixel passes through the hologram element 703 as it is, and is recognized as a bright pattern by the observer.

 Here, the light and dark patterns corresponding to 0N and 0FF of the liquid crystal element are inverted between the light from the light source 704 and the external light. This can be dealt with by inverting the pattern of the video signal in accordance with the selection of the light source.

 Strictly speaking, the light from the light source 704 passes through the liquid crystal element only once, whereas the external light 710 is reflected by the mirror and travels twice on the outward and return paths. Pass through the liquid crystal element. For this reason, the modulation ratio in the liquid crystal element 701 is different. This can be dealt with by correcting the video signal according to the selection of the light source, because the modulation degree of the single pass and the double pass can be estimated in advance.

 As described above, by setting the polarization dependences of the hologram elements 720 and 703 differently, it is possible to achieve both the transmission mode and the reflection mode. .

 As a result of observing the actually manufactured image display device, it is possible to clearly see the image by using the light source 704 in a dark room, and to use the light source 704 under bright illumination light. It was possible to perform image recognition without turning on. Thus, by using this image display device, it is possible to select a light source according to the environment such as a dark place or a source of bright illumination light. Therefore, it is possible to improve power consumption efficiency and improve the visibility of images under various environments.

In addition, it is possible to detect the brightness of the illumination light in an environment where the image display device is used, and to automatically select a light source or set the intensity of the light source. The display capability can be further improved. Noh.

 (Embodiment B5-5)

 FIG. 34 shows an image display device configured by combining hologram elements 72 2 and 73 3 similar to those of Embodiment B5-1 with a color filter 7221. As a light source 704, a fluorescent lamp was used as white light without passing through a filter. The liquid crystal element 720 has the same structure as the liquid crystal element 720 of Embodiment B5-1, but has three times the pixel density and the red color of the color filter 72 1. The three pixels corresponding to the (R), green (G), and blue (B) regions are grouped to display a single image at the same pixel density as the liquid crystal element 720. I have. The color filter 72 1 selectively transmits light of any one of the R, G, and B wavelengths in each region corresponding to each pixel of the liquid crystal element 720, and transmits light of another wavelength. It is designed to absorb light.

 In this image display device, the light including the P-polarized light and the S-polarized light emitted from the light source 704 is diffracted upward by the hologram element 720 in the figure. Therefore, the S-polarized light does not enter the color filter 721, but only the P-polarized light enters the color filter 721.

Light corresponding to each of the R, G, and B wavelengths that has passed through the color filter 721 enters each pixel of the liquid crystal element 720. Then, the polarization direction is modulated according to 0 N, OFF of each pixel. As a result, the light passing through the ON pixel passes through the hologram element 703 as it is and reaches the observer. In addition, the light that has passed through the OFF pixel is diffracted upward by the hologram element 703 in the same figure, so that the light falls outside the field of view of the observer, and as a light intensity for the observer. The dark pattern is not recognized. In Fig. 34, all pixels corresponding to R, G, and B are 0 for simplicity. The case of N and OFF is shown. For each pixel where light of each wavelength is incident, the applied electric field is controlled independently and passed through the hologram element 703. The observer receives light of the selected color out of the light of each wavelength of R, G, and B. Therefore, the display of a color image as a combination of the light of the selected color arrives. Will be possible.

 Here, regarding the influence of the chromatic dispersion of the hologram element 703 on each wavelength, the diffraction angle is set to be large so that even light of a short wavelength having a small diffraction angle is out of the viewing range of the observer. Just set it. In other words, any light of each wavelength that has passed through the pixel corresponding to OFF is diffracted by the hologram element 703 out of the observer's field of view, and is not recognized as light intensity, causing problems such as color mixing. Does not occur.

 In addition, light that has passed through the ON pixels is not normally subjected to diffraction by the hologram element 703. However, when the liquid crystal material forming the hologram element 703 has wavelength dispersion, the value of n = Ne-1Nο may vary depending on the wavelength, and the inside of the element becomes an isotropic medium. It cannot be considered. In this case, an angle difference is generated in the transmitted light of each wavelength, and the light is visually recognized by an observer as color bleeding or the like. However, in the case of transmission, if the distance from the hologram element 703 of the observer is not far away, no significant deterioration in image quality occurs. When color image signals of R, G, and B were input to the actually manufactured image display device and observed about 30 cm away from the hologram element 703, almost no color mixing or color bleeding was observed. It was possible to observe clear images without any color.

The combination of color filters used here is not only used in the configuration shown in Fig. 34, but is used for the reflection type shown in Fig. 32 and the transmission / reflection type shown in Fig. 33. And in these modified configurations Needless to say, this is also applicable.

 (Embodiment B5-6)

 The hologram elements 720 and 703 of the image display device according to the embodiment B55 are R (0.65 μm), G (0.55 μm), and so on. And B (0.45 μm) may be used after being subjected to multiple exposure with light of each wavelength. Hereinafter, a manufacturing process of such a hologram element will be described.

 First, a liquid crystal sample is manufactured in the same manner as in the case of manufacturing the hologram element shown in FIG. 18 in Embodiment B2-1. This is set in an optical system using an Ar laser. First, as the first exposure step, exposure is performed using interference fringes corresponding to the wavelength of G (0.55 m). Go. Next, the angle of the mirror (reflection mirror) is changed, and the first exposure process is repeated to perform exposure corresponding to the wavelength of R (0.65 m). Further, an interference fringe corresponding to B (0.45 m) is similarly formed and exposed. Thereafter, a second exposure step of irradiating the liquid crystal sample with uniform light is performed in the same manner as in Embodiment B 2-1 to produce a holographic element on which interference fringes are superimposed. I can do it.

 The hologram element fabricated as described above is used in place of the hologram elements 720 and 703 in FIG. 34, and a single video signal is input to the liquid crystal element 701, and Observed from the observer's position, the hologram element is optimized for any of the R, G, and B wavelengths, so there is no problem such as color bleeding or color mixing. We were able to recognize various images. In addition, even if the observation position was moved back and forth by about 30 cm, there was no effect such as deterioration of image quality.

 (Embodiment B5-7)

The hologram element 70 of the image display apparatus according to the embodiment B55. Exposure was performed using light of each wavelength of R (0.65 m), G (0.55 / m), or B (0.45 m) as 2, 703, respectively. A stack of three hologram elements manufactured in this way may be used. The hologram element as described above is used in place of the hologram elements 720 and 703 in FIG. 34, and a color video signal is input to the liquid crystal element 701, and the observer's Observed from the position, the diffractive optics of each layer independently affected the R, G, and B wavelengths, and the wavelength dispersion was reduced. As a result, clear images could be recognized without problems such as color bleeding and color mixing. Furthermore, even if the observation position was moved back and forth by about 30 cm, there was no effect such as deterioration of image quality.

 (Embodiment B5-8)

 The image display device according to the embodiment B51-11 can be applied to an image display / illumination device. Hereinafter, an example of a device that can display road traffic information in a tunnel and perform illumination without a tunnel will be described.

As shown in FIG. 35, the image display device 731 is installed on the wall surface 732 of the tunnel. This image display device 731, for example, has a configuration similar to that of the image display device described in Embodiment B51-11, and the emission direction of the diffracted light in the hologram element travels in the tunnel. It is installed so as to face the traveling direction of the vehicle 733. That is, in the embodiment B5-1, an example in which the display image is viewed from almost the normal direction (front) of the display screen has been described. However, when the display operation is performed, the diffracted light is simultaneously displayed. As a result, an image in which the brightness is inverted from the image viewed from the front is displayed. Therefore, by inputting image data in which the brightness is inverted beforehand as the image data to be input to the image display device, the diffracted light is used to reduce the normal to the display screen. Those who lean An image that can be viewed from the opposite side can be displayed. Here, the direction in which the diffracted light is emitted, that is, the direction in which the displayed image is viewed by the diffracted light, can be set by the inclination or pitch of the periodic structure of the hologram element. Therefore, this display device can be applied to various devices that require a display image to be viewed obliquely. On the other hand, when an image is displayed by diffracted light, light transmitted through the hologram element is emitted in the normal direction of the display screen. Although the image formed by this emitted light cannot be seen from an oblique direction, it plays a role as illumination light in dark environments such as at night or in a tunnel. It can be used as That is, a device having both functions of an image display device and a lighting device can be configured. In this way, the functions of the image display device and the illumination device can be provided because light that is not used for image display in a liquid crystal display using a normal polarizer is absorbed by the polarizer. This is because a display device using a hologram element as described above emits transmitted light and diffraction light equally in principle, while it cannot be used for illumination.

 This is a feature of the image display device having a configuration in which light is split by the hologram elements 72 and 703 in the present invention.

 By arranging a plurality of image display devices 731 on the wall 732, it is possible to use the system so that the observer can recognize the image information step by step according to the traveling position of the vehicle. This is effective when it is necessary to call attention by traffic information or to facilitate recognition.

Actually, the experiment was conducted with the image display device 731 placed in a laboratory that imitated the structure in the tunnel as shown in Fig. 35. Image that could be displayed. Also, the light emitted to the front of the image display device 731 is It was also confirmed that it also plays a role as illumination light.

 Such an image display / illumination device can be applied not only to the inside of the tunnel but also to traffic information display and lighting on a normal highway or an expressway, with priority given to other specific directions. Needless to say, the present invention can be applied to a method of displaying image information.

 (Embodiment B5-9)

 An example of an image display device having a polarization conversion element configured using the same hologram element as that of Embodiment B 511 will be described.

 This image display device is provided with hologram elements 741 to 744 arranged on the same plane instead of hologram element 720 of embodiment B51-11. Further, between the hologram elements 743, 744 and the liquid crystal element 701, phase difference plates (human / 2 plates) 745, 746 are provided. As the light source 704, a light source obtained by passing a green filter through a fluorescent lamp as in Embodiment B5-1 was used. Other configurations are the same as those in Embodiment B5-1.

 In this image display device, of the light emitted from the light source 704, the P-polarized light passes through the diffractive optical elements 741 and 742 as it is and enters the liquid crystal element 701. The S-polarized light is diffracted almost horizontally at an angle of about 90 °, and the hologram elements 743, 7 are arranged at the sides. 4 It is incident on 4. The light incident on the hologram elements 743, 744 is diffracted by the hologram elements 743, 744 at an angle of about 90 °. The light diffracted by the hologram elements 743 and 744 has its polarization plane rotated by 90 ° by the phase difference plates 745 and 746, and is converted into P-polarized light by the liquid crystal element. It is almost perpendicular to 70 1.

That is, the hologram element 7 41-7 4 4 and the phase difference plate 7 4 5, 746 constitutes a polarization conversion element, and the light from the light source 704 enters the liquid crystal element 701 as a light wave with a uniform polarization plane (in this case, P-polarized light). . Therefore, the light utilization efficiency is increased (theoretically about twice), and a bright image can be displayed.

 In addition, since the irradiation area of the light source 704 can be enlarged, the light from the light source 704 having a small area can be enlarged to display an image by enlarging the irradiation area. It is also effective in reducing power consumption.

 The light passing through the liquid crystal element 701 enters another holographic element 703 whose polarization direction is modulated in accordance with a signal applied to the pixel.

 Here, the S-polarized light is diffracted upward in the plane of the paper and emitted out of the viewing range of the observer.

 The P-polarized light passes through the hologram element 703 as it is, and is recognized by an observer.

 When observing the holographic element 703 in the direction from the observer's position, the image corresponding to the input signal applied was correctly recognized.

 As described above, the image display device configured here can effectively use almost all of the light waves from the light source for image display, and can enlarge the illumination area.

 (Embodiment B 5 — 10)

Another example of a small-sized image display device having a polarization conversion element constituted by using the same hologram element as that of Embodiment B51-11 will be described. FIG. 37 schematically shows a small-sized display device according to Embodiment B of the present invention. The light wave from the light source 704 enters the hologram element 751 from the lateral direction, and the P-polarized light is diffracted by about 90 ° by the diffractive optical element and enters the liquid crystal element 701. The S-polarized light passes through the hologram element 751, and enters the other hologram element 752. The diffractive optical element 752 is formed so as to generate a refractive index distribution with respect to the S-polarized light, and the S-polarized light incident on the holographic element 752 is diffracted by approximately 90 ° and emitted. . Thereafter, the light passes through the half plate 753, the polarization plane is rotated by 90 °, and enters the liquid crystal element 701 as P-polarized light.

 Therefore, almost all of the light amount from the light source 704 can be used for the display of the liquid crystal element as in the embodiment B5-10. Further, since light is incident from the lateral direction, it is possible to use a seesle-type function or to use an external light source and an internal light source in combination as in Embodiment B5-4.

 In the image display device actually manufactured, the light source 704 used was a fluorescent lamp that passed through a green filter. Light with a wavelength of about 11 was emitted. As the liquid crystal element, a small liquid crystal panel having a resolution of about 0.9 inch VGA (640 × 480) was used. When an image signal is input to this, light passing through the liquid crystal element 701 enters another holographic element 703 whose polarization direction is modulated in accordance with a signal applied to the pixel.

 Here, the S-polarized light is diffracted upward in the plane of the paper and emitted out of the viewing range of the observer. The P-polarized light passes through the hologram element 703 as it is, and is recognized by the observer.

Furthermore, this time, the magnifying optical system 754 was used on the light emission side of the holographic element 703. Here, a planar Fresnel lens was used as the magnifying optical system. As a magnifying optical system, a convex lens or a liquid crystal lens using an in-plane change in refractive index can be used. If a magnifying optical system is constructed with a thin lens, a small system can be constructed. When the direction of the holographic element 703 was observed from the observer's position, the image corresponding to the input signal applied was correctly recognized. Also, despite the use of a small 0.9-inch liquid crystal panel this time, the effect of the magnifying optical system 754 gives the observer a distance from the hologram element 703. The displayed image was enlarged and could be clearly recognized.

 The configuration shown in Fig. 37 allows the whole system to be miniaturized, and can be used as a very small image display device that can be used as a micro display for a portable information terminal. Be expected.

 (Embodiment B6)

 Embodiment] An image display device configured using the hologram element shown in B 1 will be described.

 Figure 38 (a) shows the configuration of the image display device. In this image display device, the hologram element 820 according to the present invention is used for the knock light unit of the transmission type liquid crystal panel 819.

 The luminous flux 82 4 from the light source 82 3 enters from the end face of the light guide 82 1, propagates through the light guide 82 1, and the hologram element 82 0 of the present invention installed on the back surface Thus, the light is diffracted in a direction substantially normal to the substrate of the liquid crystal panel 8 19. The luminous flux 822 incident on the liquid crystal panel 819 is modulated to display an image.

 A reflective mirror 823 is provided on the back of the hologram element 820 so that the light transmitted through the hologram element 820 can be further reflected. For example, it is preferable to form a dot (not shown, a large number of well-known technologies other than the conventional example 7) that scatters light on the reflection mirrors 823.

It is sufficient that the liquid crystal panel 8 19 is a transmissive type, and its driving method is Any type of liquid crystal panel can be used regardless of the method and liquid crystal material. It should be noted that a reflection type liquid crystal panel which is also used as a transmission type according to the brightness of external light may be used.

 As the light source 823, for example, CCFFT can be used, and a reflecting mirror 825 may be provided as disclosed in a large number of examples including the conventional example 8. A resin material such as acryl can be mainly used as the light guide 821, and many such materials are disclosed in, for example, a conventional example 7 and Japanese Patent Application Laid-Open No. Hei 9-57443. As shown, a wedge-shaped configuration is also possible. The basic function of the hologram element 820 is that a specific polarization component in the non-polarized light beam 824 that has entered the hologram element is approximately in the normal direction of the liquid crystal panel 819, and Since it is diffracted selectively within a specific solid angle, it can function as a hologram element or as a mere isotropic medium depending on the presence or absence of a voltage.

 That is, as shown in Figs. 39 (a) and (b), for example, it can function as a hologram element when no voltage is applied, and can function as an isotropic medium when voltage is applied. You. When functioning as a hologram element, the hologram element 820 according to the present invention uses only a specific polarization component in the non-polarized incident light beam 824 in a simplified form of a liquid crystal panel. Selectively diffracts linearly and within a specific solid angle.

 At this time, if the liquid crystal panel is of a polarization type, that is, a method of modulating only a specific polarized light, and a polarizing plate (not shown) is provided on the light incident side, the polarization direction of the polarizing plate (polarizer) The direction of oscillation of the electric field vector of the polarized light transmitted by the hologram element and the direction of polarization of the polarized light that is selectively diffracted by the hologram element (the oscillation direction of the electric field vector) are made to substantially match. For the first time, high efficiency can be realized.

On the other hand, when a voltage is applied, the hologram element 820 of the present invention is substantially It becomes an isotropic medium, and the incident light beam 824 passes through the hologram element 820, and the light beam scattered by the reflection mirror 823 provided on the back surface of the light beam 8 It is incident on 9. In this case, the output luminous flux of the liquid crystal panel 819 is almost one by the dot provided on the reflection mirror 823 in the same manner as when illuminated by the conventional backlight. Is spread in a similar manner.

 As described above, in the image display device using the hologram element 82 of the present invention, when no voltage is applied, the illumination light is diffracted into a narrow solid angle substantially in the normal direction. As a result, the brightness when observing the liquid crystal panel 8 19 from the front can be made extremely high, and the brightness when observing from the front decreases by applying voltage, but the wide field of view Corners can be secured.

 When the hologram element is used for a knock light unit of a liquid crystal panel as in the present invention, and the diffracted light has directivity and is viewed from the front (when viewed from the normal direction of the liquid crystal panel). Many examples of increasing the brightness of (1), such as Conventional Example 7 to Conventional Example 10, have been disclosed. However, in the above example, the hologram element has a single function of always diffracting incident light. It does not have the ability to switch the viewing angle as in the hologram element 82 of the present invention.

 Further, in Conventional Examples 1 and 2, a holographic element that can be switched is disclosed, but no specific use as a backlight of a liquid crystal panel is disclosed. As mentioned above, high efficiency can be realized for the first time by matching the polarization direction of the polarizing plate of the liquid crystal panel with the polarization direction of the light selectively diffracted by the hologram element. It is.

Switching between the brightness and the viewing angle of the image possessed by the image display device of the present invention This function is extremely valuable when used as a display for personal computers or portable information terminals, regardless of whether they are stationary or laptop.

 In other words, when viewing an image on an individual basis, the viewing angle (meaning equivalent to the range in which the image can be viewed) does not need to be unnecessarily wide; Is sufficient. According to the present invention, an image is output almost in the direction of the operator observing the image from the front, so that the power consumption of the lamp can be reduced. On the other hand, when observing images with a large number of people, a wider viewing angle is desirable. Therefore, the function of changing the viewing angle between the case of observing an image by an individual as in the present invention and the case of observing the image by a large number of people is important. However, strictly, the viewing angle cannot be changed. Instead, the holographic element 82 of the present invention determines the amount of light reflected within a specific narrow solid angle by the applied voltage. Means that it can be controlled. Next, a method for manufacturing a hologram element used in Embodiment B will be described.

 The hologram element 820 used in the present embodiment B is manufactured from the two glass substrates 502 on which the ITO 501 is formed as described in the embodiments B1 and 4-1. The cell can be fabricated by injecting, for example, a mixture of a UV-curable liquid crystal and a non-polymerizable liquid crystal as a photo-curable liquid crystal, and illuminating a two-beam interference image.

However, the feature is that the object light is made to enter the substrate substantially perpendicularly at the angle at which the light flux enters the reference light. In addition, by performing two-beam interference exposure with a voltage applied at this time, a desired interference script as shown in FIG. 39, for example, is formed, and a UV cure is applied to a portion where the interference script has a high intensity. The non-polymerizable liquid crystal is separated into the weak liquid crystal and the weak portion, and the liquid crystal of the present invention is used. A program element 820 is manufactured.

 In actual production, the object light and the reference light do not need to be plane waves, and for example, a luminous flux that spreads within a specific solid angle as the object light is used as the reference light. It is preferable to use a light beam that propagates 1 and enters the hologram element from an angle range almost equal to that of the light beam.

Further, in the above configuration, for example, 11 ^> 0501 of the holographic element 8200 according to the present invention is patterned, and the applied voltage is varied for each region to locally adjust the refractive index anisotropy. You can also control it. This makes it possible to locally optimize the efficiency of the hologram element 820. Further, for example, as disclosed in Conventional Example 7, holographic elements are arranged in a minute mosaic shape, and individual holographic elements are arranged so as to exhibit maximum efficiency with respect to the incident light wavelength and the incident angle. The system element may be optimized.

 Further, as shown in FIG. 38 (b), a 义 plate 27 is provided between the hologram element 820 according to the present invention and the reflection mirror 823, and the reflection mirror is provided. For example, by arranging the grid 823 not parallel to the hologram element 820 but at an angle of about 5 °, for example, a voltage is applied to the hologram element 820 according to the present invention. In the mode in which the extraordinary ray is selectively diffracted, the ordinary ray 828 that passes through the hologram element 82 0 is converted into an extraordinary ray and is incident on the hologram element 820 again. I can do it.

At this time, since the reflecting mirror 823 is installed at an angle, the reflected light flux 829 from the reflecting mirror 823 is holographically dependent on the angular dependence of the hologram element 820. The light beam transmitted through the optical element 820 and reflected by the hologram element 820 is incident on the liquid crystal panel 819 as the same polarized light (in this case, P-polarized light) as the light beam 822. Light efficiency Can be higher.

 As described above, the image display device according to Embodiment B adjusts the voltage applied to the hologram element 820 according to the present invention so that the luminous flux is within a specific solid angle. The amount of output can be controlled. As a result, it is possible to select a bright image display with a narrow viewing angle but a wide viewing angle, which is slightly darker, as necessary.

 The image display device configured in Embodiment B is not only a display for a stationary or notebook personal computer, but also a display for a portable information terminal or a portable communication device. However, it can be used as an in-vehicle head-up display.

 (Embodiment B7)

 An image display device according to the present invention configured as Embodiment B7 of the present invention will be described. The image display device of the embodiment B is a so-called conventional direct-view type liquid crystal panel. As a liquid crystal material, a mixture of a photocurable liquid crystal and a non-polymerizable liquid crystal is used. A lattice-like light (wavelength is a wavelength for curing the photocurable liquid crystal) is illuminated, and a microcell structure surrounding each pixel is formed by a photoinduced phase separation phenomenon. However, ne and no of the photocurable liquid crystal after curing are substantially equal to ne and n0 of the non-polymerizable liquid crystal, respectively.

 With the above microcell configuration, the liquid crystal molecules are aligned in an axially symmetrical manner stabilized by the photo-curing reaction by the self-alignment force in the liquid crystal region, and a wide viewing angle and a high contrast are obtained. realizable.

Next, the difference between the conventional example and the image display device according to Embodiment B will be described. The effect that the microcell can achieve the improvement of the viewing angle and the high contrast is disclosed in, for example, Conventional Example 6, but in Conventional Example 6, the mixture of the photocurable resin and the liquid crystal is simply added to the grid. Light (wavelength Is the wavelength at which the photocurable resin is cured), and only the microcell structure surrounding each pixel is formed by the photo-induced phase separation phenomenon. No anisotropy is described. In general, a photocurable resin has a slight but birefringent property and exhibits a slight refractive index anisotropy. Therefore, when displaying black, the contrast is good for the vertically incident light beam, but for the obliquely incident light beam, the lattice part is conspicuous as a discontinuous region. The disadvantage was poor uniformity.

 However, in the image display device of Embodiment B, the photocurable liquid crystal is cured in the same orientation as that of the non-polymerizable liquid crystal when displaying black, and the optical curing of the photocurable liquid crystal is performed. In order to make the anisotropy almost equal to the optical anisotropy of the non-polymerizable liquid crystal, the microcell portion becomes conspicuous in black display and the decrease in contrast is suppressed. As a result, it was possible to display an extremely uniform image.

 (Embodiment B 8 — 1)

 FIG. 40 shows an outline of an optical information processing apparatus using the volume hologram element shown in the embodiment B2-1, which is configured in the embodiment B8-1 of the present invention. Light emitted from the semiconductor laser 901, which emits polarized light, passes through the volume hologram element 521, as it is, and passes through the 1/4 wavelength plate 905 by the imaging lens 90.4. Through the optical storage medium 906 In this case, the laser light passing through the volume hologram element 5 21 is not diffracted, and almost all the light emitted from the semiconductor laser 90 1 is focused on the optical storage medium 9 06 .

Next, the light reflected by the optical storage medium 906 passes through the 1Z4 wavelength plate 905 again, and is converged by the imaging lens 904. At this time, the reflected light passes through the quarter-wave plate twice, so that its polarization direction When the light is emitted from the semiconductor laser 901, the polarization direction rotates 90 °. Therefore, in this case, the reflected light is diffracted according to the predetermined wavefront formed on the volume hologram element 521, and is converged on the photodetector 902.

 Here, an optical signal is detected for each of the divided areas on the photodetector 902, and a focus shift, a tracking shift, and a signal of information recorded on the optical storage medium are detected. . At this time, the amount of light guided to the photodetector 902 is substantially determined by the light use efficiency of the volume hologram element 521 by the polarization separation on the forward path and the diffraction efficiency on the return path.

 The principle and structure of the volume hologram element 52 1 of the present invention are shown in FIG. 41 and FIG. Figure 41 shows a refractive index ellipsoid of a uniaxial optical crystal. Figure 41 (a) shows the refractive index ellipsoid when the optical axis is in the Y direction. At this time, the light whose polarization direction exists in the YZ plane becomes an extraordinary ray and has a refractive index of Ne. In addition, light having a polarization direction in the XZ plane is an ordinary ray and has a refractive index of No. FIG. 41 (b) shows a refractive index ellipsoid when the optical axis of the uniaxial optical crystal is tilted 90 ° from the Y direction. In this case, a refractive index of No is shown for light having a polarization direction in the Y-Z plane, and a refractive index of No is shown for light having a polarization direction in the X-Z plane. Will be shown. In the state where the optical axis is between (a) and (b), for light whose polarization direction exists in the Y-Z plane, Ne and N o (N e) correspond to the state of inclination of the optical axis. The intermediate value of the refractive index of N o) is taken. On the other hand, for light whose polarization direction exists in the XZ plane, the refractive index always shows No, regardless of the tilt of the optical axis.

As described above, an optical medium having refractive index anisotropy has a refractive index distribution ranging from Ne to No with respect to the incident polarization direction. In some cases, a refractive index distribution of only N o is shown regardless of the tilt of the optical axis.

 FIG. 18 is a diagram showing a cross-sectional configuration of a volume hologram element. The inside of this element has a periodic layer structure that is inclined from the surface on which light enters to the thickness direction. The optical media having anisotropy in refractive index are arranged between adjacent layers such that the inclination of the optical axis is parallel to the surface of the volume hologram element 52 1. The other is arranged perpendicular to the surface.

 Here, the volume hologram element 52 1 is configured such that light having a polarization direction perpendicular to the plane of FIG. 18 is an ordinary ray and light having a polarization direction parallel to the plane of FIG. 18 is an extraordinary ray. Then, the behavior when these lights enter the volume hologram element 521 will be considered.

 First, when ordinary light is incident, it is treated in the same way as when light having a polarization direction is incident on the X-Z plane in Fig. 41, so it is not related to the direction of the optical axis of the optical medium constituting each layer. Therefore, the refractive index of each layer is No. In other words, since it is equivalent to the existence of a uniform medium having a refractive index of N 0, the ordinary ray incident on the medium is not affected by diffraction, and is transmitted as it is as shown in FIG. Will be done.

 Next, consider the case where an extraordinary ray is incident. In a layer in which the optical axis of the optical medium having the refractive index anisotropy is arranged parallel to the incident surface, the polarization direction of the incident light is parallel to the optical axis. This corresponds to the case where light having a polarization direction on the Y-Z plane in Fig. 41 is incident on an optical medium having an optical axis in the Y direction in (a), and a layer having a refractive index of Ne. Will pass through.

In addition, for a layer in which the optical axis of the optical medium is perpendicular to the incident surface of the volume hologram element 521, the Y-Z plane is shown in (b) of Fig. 41. This layer is treated as having a refractive index of N o, since this corresponds to the case where light having a polarization direction is incident on the surface.

 Therefore, for the extraordinary ray, the volume hologram element 521 passes through a plurality of layers having different refractive indexes periodically in the thickness direction which is the traveling direction of the incident light. As a result, the incident light beam is subjected to a so-called Bragg diffraction effect in which light is condensed in a specific direction corresponding to the tilt angle and period pitch of this layer.

 As shown in FIG. 18, after passing through the volume hologram element 521, the extraordinary ray changes its optical path according to the layer structure formed inside the element.

 As described above, the polarization direction of light emitted from the semiconductor laser 901 is changed to the ordinary ray shown in FIG. 18 with respect to the volume hologram element 5 21 in the configuration of the optical information processing apparatus shown in FIG. Set to correspond. At this time, the light emitted from the semiconductor laser 901 is not modulated by the volume hologram element 521 and the 1 wavelength plate is formed by the imaging lens 904 without being modulated. Through the optical storage medium 906.

The light reflected here again passes through the quarter-wave plate, passes through the imaging lens 904, and enters the volume hologram element 521. At this time, since the polarization direction is rotated 90 ° with respect to the outward path, it corresponds to the case of the extraordinary ray shown in FIG. Therefore, the light is condensed on a specific direction, in this case, on the photodetector 902, corresponding to the periodic refractive index distribution corresponding to the layer structure formed inside the volume hologram element 521. It will be. By constructing a structure having a periodic structure in the thickness direction as shown in FIG. 18, the Bragg diffraction condition is applied. This is because when light having a certain wavelength enters each layer forming the periodic structure, the light scattered in each layer corresponds to the wavelength, the incident angle, and the pitch between the layers. A phenomenon occurs in which scattered components intensify in a specific direction.

 This is what is called the Bragg diffraction condition. Such a condition results in a three-dimensional configuration compared to a conventional two-dimensional diffractive optical element, and is blazed (in one direction). (Light converges).

 Therefore, the diffraction efficiency can be remarkably improved as compared with the conventional diffractive optical element, and an efficiency of 100% can be theoretically achieved. In fact, an efficiency of 90% or more can be expected even when taking into account losses in the middle. On the other hand, if a hologram element as shown in Fig. 40 is constructed with a diffractive optical element consisting of the binary as described above, the diffracted wave will be symmetrical to the higher order, including the 0th order It will be diffracted. As a result, the diffraction efficiency in the first-order direction is at most about 40%, which is a low value of less than 1/2 of the total amount of light passing through the element.

 If an optical information processing device is configured using the volume hologram element 52 1 in the present invention, it is possible to condense almost all the reflected light from the optical storage medium 906 on the photodetector 902. Therefore, there is no problem such as a decrease in S / N ratio due to a decrease in light intensity. Further, since the diffraction efficiency of the volume hologram element 521 is high, the amount of light returning to the semiconductor laser is almost nil. Therefore, the problem of instability of the oscillation of the laser which is the light source due to the feedback of the light intensity to the semiconductor laser 901 does not occur. Fig. 18 shows the case where the optical axis of the optical medium constituting the volume holographic element 5 21 has the largest difference in the refractive index at 90 ° between adjacent layers, but this angle can be set arbitrarily. By setting, it is also possible to set the refractive index difference to an intermediate value between Ne and No.

In addition, the diffraction efficiency is adjusted by selecting a refractive index distribution using this, and the intensity and pattern of the detected light can be arbitrarily determined for the photodetector 102. It is also possible to set to.

 In addition, the area of the volume hologram element 52 1 is divided into several parts, and the directions of diffraction are shifted, and the light signals are received in different areas of the photodetector 90 2, thereby defocusing, A configuration is also possible to efficiently detect various types of information such as tracking deviation.

 Furthermore, in the case where a plurality of semiconductor lasers 901 are used at different wavelengths and not only writing of optical information but also recording are performed at the same time, different periods are set according to the respective optical wavelengths. It is also possible to superimpose and record a layer structure having a structure, an angle, and the like in the volume hologram element 52 1.

 (Embodiment B 8 — 2)

 The method of manufacturing the diffractive optical element used in the optical information processing device according to the present invention will be described with reference to FIG.

 The outgoing light with a wavelength of around 36 O nm from the Ar laser 911 is passed through a mechanical shutter 912 that can be opened and closed, and the diameter is 30 mm to 5 O mm by the beam extender 913. Can be spread to a degree beam. The beam is split in two directions by beam splitter 915, and it corresponds to the structure of interference fringes formed on volume hologram element 521 by mirror 906. Irradiation at an angle. One of the beams split by the beam splitter 915 has a shutter 405 disposed therein.

 Next, a manufacturing process of the cell of the volume hologram element 52 1 will be described.

Two transparent conductive electrodes having, for example, IT 0 formed on a glass substrate were prepared. After cleaning these substrates to remove dust, an alignment film made of a polymer, for example, polyimide is applied by a spin coating method or the like, and heat treatment is performed. The alignment film. Formed on a plate.

 Thereafter, a rubbing process is performed in a specific direction using a roller or the like, a seal is printed around one substrate, and beads having a diameter of about 5 m to 20 m are dispersed on the other substrate. The two substrates were bonded together so that the rubbing directions were paired with each other to form an empty cell.

 Liquid crystal was used as the optical medium having the refractive index anisotropy, and injection was performed into the empty cell fabricated here. The liquid crystal used here has a positive dielectric anisotropy, but it is also possible to use a liquid crystal having a negative dielectric anisotropy.

Contains a photopolymerizable liquid crystal monomer or a photo-crosslinkable liquid crystal polymer.The liquid crystal is hardened by irradiation with light in the ultraviolet region around 360 nm, and the direction of the liquid crystal molecules is fixed. It has the characteristics to be generalized. The injection was performed at room temperature in an air atmosphere, but the injection may be performed at a high temperature of about 40 ° (about 60 ° C or in a vacuum atmosphere. The liquid crystal sample was completed by sealing the vicinity of the air hole with a sealant, and the liquid crystal sample prepared as described above was fabricated into a volume hologram element 521 in the optical system shown in Fig. 42. With the shutters 912 and 405 first opened, adjust so that interference fringes of about lzm pitch are formed at the sample position. At this time, the focusing angle of the two light beams by the mirror 906 is about 15 ° to 45 °, and the irradiation intensity of the Ar laser is about 50 mW to 100 mW. Next, the process of forming interference fringes on a liquid crystal sample using a laser will be described. The liquid crystal sample is set while the shutter 405 is open, and the shutter 912 is opened for a predetermined time, here about 1 minute, and then closed. This is the first step, and by this step, the liquid crystal sample is The liquid crystal is cured in the area belonging to the bright area where the intensity of the interference fringes formed by the interference of the two light beams is hardened, and the molecular axis is fixed in the direction in which the liquid crystal molecules were initially aligned. . Here, since a liquid crystal having a positive dielectric anisotropy is used, initially, the liquid crystal molecules are uniformly oriented in a direction parallel to the glass substrate, and this state is preserved. become. On the other hand, in the region belonging to the dark portion of the interference fringes, the light intensity is lower than that in the bright portion, and therefore, hardening of the liquid crystal molecules is hardly promoted in the first step.

 Next, as a second step, an AC electric field of about 5 (V // m) is applied between the ITO electrodes as transparent conductive electrodes formed inside the two glass substrates of the liquid crystal sample. . Due to the application of the electric field, uncured liquid crystal molecules in a region belonging to a dark portion of the interference fringes are tilted in a direction perpendicular to the glass substrate. Since the tilt angle at this time is proportional to the applied electric field, a desired tilt angle, that is, a refractive index difference can be obtained by adjusting the magnitude of the electric field.

 With the voltage applied as described above, the shutter 405 is closed, and the entire surface of the volume hologram element 52 1 is irradiated with light having a uniform intensity distribution without forming interference fringes for about 5 minutes. Then, the entire area including the liquid crystal in the uncured dark area is completely cured.

By performing the first and second steps as described above, a volume hologram element 52 1 having a structure as shown in FIG. 18 was produced. The diffraction efficiency of this device was measured using a He-Ne laser while changing the incident polarization direction. The transmittance to ordinary light was around 98%, indicating a high transmittance. The diffraction efficiency in the primary direction for extraordinary rays was about 90%, and good results were obtained. Therefore, the volume hologram element fabricated here has high polarization separation characteristics and diffraction efficiency, and is promising as a diffractive optical element used in an information processing device. found.

 (Embodiment B 8 — 3)

 Using two glass substrates facing each other, a process similar to that of Embodiment B82-12 was performed from the formation of the alignment film, and a liquid crystal sample was prototyped. This sample was set in the optical system shown in Fig. 42, and as a first step, the light portion of the interference fringes was exposed.

 Next, as a second step, a magnetic field is applied to the volume hologram sample 5 21 shown in FIG. 42 in order to change the alignment direction of the liquid crystal molecules in the region belonging to the dark stripe from the initial position. Settings were made. Specifically, a magnetic field was formed around the liquid crystal sample by a superconducting magnet. Since liquid crystals have dielectric anisotropy, the molecular axis of liquid crystal molecules can be changed by applying a magnetic field as well as an electric field. By the application of the magnetic field as described above, the liquid crystal molecules in the dark area are changed in a direction perpendicular to the glass substrate. Then, in this state, the shutter 405 is closed in the same manner as in Embodiment B8-2, and uniform light irradiation is performed on the liquid crystal sample to cure the entire panel. went.

 When a magnetic field is applied, the liquid crystal sample does not require the formation of ITO or the like as a transparent conductive electrode, so this process is omitted, the configuration is simple, and the production can be performed at lower cost. Furthermore, since the influence of the reflected light due to the difference in the refractive index at the interface between glass and ITO is eliminated, the transmittance increases, and the function as a diffractive optical element is improved.

The diffraction efficiency with respect to the polarization direction of the volume hologram element manufactured by the above-described process was measured by the same method as that of Embodiment B8-2. As a result, it has a diffraction efficiency of 90% or more, and it is possible to appropriately control the direction of liquid crystal molecules even by a method by applying a magnetic field. found. (Embodiment B 8 — 4)

 From the step of applying an alignment film to a glass substrate, a prototype of a liquid crystal sample was manufactured in the same manner as in Embodiment B8-3. In Embodiment B, polyvinyl cinnamate (PVCi) was used as the alignment film, and the roller rubbing step was omitted. This sample was set in the optical system shown in Fig. 42. This time, in this system, a polarizer is provided immediately after the beam expander 913, and only the linear polarization component of the laser beam is used.

 First, as a first step, exposure of a region belonging to the bright portion of the interference fringes was performed in the same manner as in Embodiment B8-2. At this time, the interference fringe pattern consists only of the linearly polarized light component of the laser light. When a polymer film is irradiated with linearly polarized light as a light source, molecules whose main chain (or side chain) is oriented in the polarization direction from randomly oriented polymers mainly absorb light. A photoreaction occurs, and the film exhibits optical anisotropy. In a polymer material, the photoreaction process (photoisomerization, photopolymerization, photodecomposition) of the polymer can be controlled by the polarization direction of the irradiated light and the angle formed by the polymer.

 Therefore, by controlling the polarization direction of the light in the ultraviolet region that forms the interference fringes, the settings were made so that the orientation direction of the liquid crystal molecules was parallel to the glass substrate. .

Next, in the second step, a half-wave plate was placed immediately after the polarizer, and the polarization direction of the laser beam was rotated 90 °. Then, the shutter 405 was closed, and the liquid crystal sample was irradiated with uniform light having a polarization direction perpendicular to the polarization direction in the first step. Against the bright portion in the region belonging to the dark space, since the light polarization direction is 9 0 ⁰ rotation is irradiated, the alignment direction of liquid crystal molecules is immobilized to change from the position of the first step You.

 The above process makes it possible to form a periodic structure in which the directions of liquid crystal molecules are different in the layers corresponding to the bright and dark portions of the interference fringes. In this case, since the liquid crystal molecules are aligned by irradiating light, it can be performed together with exposure of interference fringes, and the manufacturing process can be simplified. In addition, the rubbing method using a mouth can be carried out in a non-contact manner, preventing dust and the like from being mixed, establishing a highly reliable manufacturing process technology, and enabling mass production. Will be able to respond stably.

 The diffraction efficiency of the volume hologram element 521 manufactured here was evaluated in the same manner as in Embodiments B8-2 and B3. As a result, the diffraction efficiency was about 70%, and although the diffraction efficiency was slightly reduced, an efficiency of 50% or more was obtained, and a three-dimensional periodic structure was formed. It became clear that a diffractive optical element was manufactured.

 In order to improve the orientation of liquid crystal molecules, a process of irradiating light with a wavelength in the ultraviolet region having a specific polarization direction after applying PVC i as an alignment film and before assembling the cell was introduced. You may.

 (Embodiment B 8 — 5)

 Using a process similar to that of Embodiment B 8-2, a liquid crystal sample was prototyped. This time, a mask was applied to half the area of the sample, and the optical system shown in Fig. 42 was set up. Then, the first and second steps were performed in the same manner as in Embodiment B8-2 to produce a volume hologram in a maskless region.

Next, the beam angle of the two light beams was changed by about 5 ° by changing the angle of the mirror 9 16 shown in FIG. Then, the mask portion of the previous sample was removed, and the first and second steps were repeated on this portion to produce a volume hologram. As a result of evaluation of the volume holographic device 521 manufactured as described above, light was diffracted in two different directions with respect to the irradiation of the extraordinary ray on the entire surface of the device.

 At this time, the respective diffraction efficiencies were about 90%, and it was found that different layer structures could be favorably produced in a plurality of regions. If this is applied to the configuration shown in FIG. 40, since it is divided in two directions by the volume hologram element 521, signal detection can be performed at once in different regions on the photodetector 902. This makes it possible to efficiently detect signals such as defocus and tracking deviation.

 (Embodiment B8-6)

 A liquid crystal sample was manufactured in the same manner as in Embodiment B8-2. This was introduced into the optical system shown in Fig. 42, and the first step was performed to expose an area belonging to the bright part of the interference fringes. Here, the angle of the mirror 916 is changed by about 5 ° to form interference fringes of different periods, and in this state, the first step is repeated to expose the light area. went.

 Next, similarly to the embodiment B8-2, the shutter 405 is closed, and a second step of irradiating the uniform hologram element 521 with uniform light is performed to perform the volume hologram. The device was fabricated.

The volume hologram element 521 manufactured as described above was evaluated. Using an extraordinary ray, the angle of the laser for measuring the diffraction efficiency was set to a direction corresponding to two exposures of the fringe, and each was measured at a different angle. The diffraction efficiency was about 75% to 80% in each case. Although the diffraction efficiency is somewhat reduced by forming interference fringes in a superimposed manner, it can be considered that this can be improved by adjusting the thickness of the liquid crystal sample to a large extent. On the other hand, it has a transmittance of about 98% with respect to ordinary rays as in Embodiment B8-2. As described above, it was possible to fabricate the volume hologram element 521 by superimposing interference fringes. This is considered to be effective in an optical information processing device that performs optical reading and recording using a plurality of lasers having different wavelengths.

 As described above, in Embodiment B, the configuration of the diffractive optical element used in the optical information processing device using the optical medium having the refractive index anisotropy and the manufacturing method thereof have been described.

 Optical media having refractive index anisotropy include lithium niobate and K

It is also possible to use a uniaxial crystal having an electro-optical effect such as D2P04,? —BaB204, PLZT, or a biaxial crystal such as KTP04. By using a medium having a refractive index anisotropy including an optical crystal and the like, it is possible to exhibit more effects.

 Needless to say, it can be used as a recording-only or read-only device. Industrial applicability

 As described above, according to the present invention, it is possible to convert an output light beam of a large lamp of an illuminant into an output light beam of a small illuminant. It can be dramatically improved. Furthermore, the loss of the light-collecting efficiency or the polarization-conversion efficiency of the integrator and the polarization conversion element caused by the aberration of the light-converging optical system caused by the size of the light-emitting body. It is possible to display a uniform, bright (high projection efficiency) image.

Further, as described above, according to the present invention, a hologram element capable of switching incident light to diffraction / straight traveling, and having extremely small diffraction of an extraordinary ray obliquely incident upon straight traveling is provided. can do. Also the book By using the hologram element of the present invention, an inexpensive and highly efficient polarization separation function can be realized, and a highly efficient image display can be configured using the function.

 Further, by using the hologram element of the present invention, it is possible to display a bright image with a narrow viewing angle and a bright image with a small viewing angle but a wide viewing angle as needed. A switchable direct-view image display device can be configured.

 Therefore, the present invention can be used and useful in the field of such an image display device and the like.

Reward 1 Refractive index difference Average refractive index Grating pitch Diffraction grating thickness Bragg angle

Δη (Νθ-Νο) Ne-No / 2 (μ-m) (m) (Aim) (°)

71 1 0.083

1.323 10 0.55 12 2 0.145 1.591 1.323 10 0.55 12

Claims

Scope of Claim (1) Having multiple regions with different material compositions,

 The plurality of regions are a first region made of a photocurable liquid crystal that is cured by at least a specific wavelength and has a refractive index anisotropy;

 A second region composed of a non-curable liquid crystal (hereinafter abbreviated as non-polymerizable liquid crystal) according to the wavelength,

 The photocurable liquid crystal after curing has a refractive index for ordinary light and an extraordinary ray which are substantially equal to the refractive index for ordinary light and the extraordinary ray of the non-polymerizable liquid crystal, respectively. Holographic element.

(2) The switching state of the non-polymerizable liquid crystal is controlled by the voltage applied to the non-polymerizable liquid crystal, thereby controlling the refractive index of the second region with respect to the incident extraordinary ray. The hologram element according to claim 1.

(3) A mixed liquid crystal obtained by substantially uniformly mixing the photocurable liquid crystal and the non-polymerizable liquid crystal is injected between two parallel plate-shaped glass substrates arranged at a specific interval, 2. The plurality of regions are formed by subjecting the injected mixed liquid crystal to interference exposure with a laser beam having a wavelength that cures the photocurable liquid crystal. 3. Manufacturing method of hologram element.

(4) At least the hologram element according to claim 1 or 2, and illumination means for illuminating the hologram element, An image display device comprising: an image display means for displaying an image by modulating an output light beam of the hologram element.

(5) The image display device according to claim 4, wherein the hologram element selectively changes only an emission angle of a specific polarized light component from an unpolarized incident light beam.

(6) The hologram element has a function of diffracting a specific polarization component (hereinafter abbreviated as a first polarization component) in the incident light from the illuminating means in a substantially normal direction of the image display means. 5. The image display device according to claim 4, wherein the hologram element controls the function by controlling a voltage applied to the second region. 6.

(7) The image display means has a function of modulating only a specific polarization component (hereinafter, abbreviated as a second polarization component), and is selectively diffracted by the hologram element. 5. The image display device according to claim 4, wherein the directions of oscillation of the electric field vectors of the first polarization component and the second polarization component are substantially equal. (8) A human / 4-wave plate and a reflection mirror are provided on the back of the hologram element, and the installation angle of the reflection mirror is at least 5 ° with respect to the hologram element. The image display device according to claim 4, wherein: (9) At least a microcell structure surrounded by a photo-curable liquid crystal cured for each pixel, And a non-polymerizable liquid crystal in the microcell,

 In addition, the refractive index of the photocurable liquid crystal for the ordinary light after curing and the refractive index for the extraordinary light are almost equal to the refractive index of the non-polymerizable liquid crystal for the ordinary light and the refractive index for the extraordinary light, respectively. Image display device.

(10) At least a first and a second holographic element having a plate-like shape having polarization anisotropy with respect to an incident light beam and capable of selectively diffracting only the first polarization component. ,

 An angle Θ 0 between the incident light beam incident on the first hologram element and the optical axis,

 An angle S 1 formed by the first output light beam, which is obtained by diffracting the incident light beam by the first hologram element, with the optical axis,

 The angle S 2 formed by the second light flux, which is diffracted after the first output light flux is incident on the second hologram element and is output, is defined by the following equation.

 I θ 1-0 2 I> 20

 I 0 0-Θ 2 I <1 5

 A polarization splitting element characterized by satisfying the following. (11) The polarization beam splitter according to claim 1, wherein the polarization beam splitter is formed by holding a hologram material by a glass substrate.

(12) The polarization separation element according to claim 1, wherein the hologram material is a UV-curable liquid crystal. (13) The hologram material according to claim 1, wherein the hologram material is a mixture of a photopolymer and a liquid crystal polymer having sensitivity to a wavelength in a specific region. Polarization separation element. (14) A projection-type image display device including at least a polarization-type image display unit and an illumination unit that illuminates the polarization-type image display unit, wherein the polarization-type image display unit includes the polarization-type image display unit. An image is displayed by modulating and outputting a specific polarization component in the illumination light from the illumination means incident on the image display means,

 The illuminating means includes at least a light emitting means, a first light condensing means for condensing an output light beam of the light emitting means, the polarization separation element, and a plurality of minute lenses arranged in a two-dimensional array. And an integer consisting of first and second fly's eye lenses arranged at

 The polarization splitting element is disposed between the first fly-eye lens and the first focusing means, diffracts the first polarized light component of the incident light flux, and outputs the diffracted light as the second light flux. A second polarization component having a polarization direction orthogonal to the first polarization component is output as a third light flux without being substantially diffracted;

 Each lens of the first minute lens group forming the first fly-eye lens is a corresponding minute lens in the second minute lens group forming the second fly-eye lens. Focus the image of the light emitting means

And a polarization plane rotating means for rotating the polarization direction by about 90 ° at a position where the second light beam or the third light beam forms an image. (15) First and second flat holograms that are arranged substantially parallel to each other and selectively diffract a predetermined polarization component that is approximately equal to each other. With a programming element

 A diffracted light beam that is incident on the first hologram element, diffracted by the first and second hologram elements, and emitted from the second hologram element;

 The angle formed by the transmitted luminous flux that enters the first hologram element, passes through the first and second hologram elements, and exits from the second hologram element exceeds 0 °. , And less than 15 °,

 In the light beam incident on the first hologram element and diffracted by the first and second hologram elements, the light flux incident on each hologram element and the hologram thereof A polarization splitting element, wherein the angle formed by the light beam diffracted by the optical element exceeds 20 °. (16) The polarization separation element according to claim 1, wherein

 The first and second hologram elements are characterized in that a hologram material is arranged between a pair of glass substrates. (17) The polarization separation element according to claim 2, wherein

 A polarized light separating element, wherein the hologram material is obtained by curing an ultraviolet curable liquid crystal.

(18) The polarization separation element according to claim 2,

The hologram material is obtained by curing a mixture of a photopolymer and a liquid crystal polymer having curability in response to irradiation of light having a predetermined wavelength. A polarization splitting element characterized in that:

(19) Light emitting means and

 A polarization splitting element for differentiating the optical paths of polarization components in different directions in the incident light beam;

 Condensing means for condensing the diffracted light flux and transmitted light flux emitted from the polarization splitting means at first and second positions different from each other,

 An image display device comprising: a polarization plane rotating means for rotating a polarization direction of an incident polarization component at one of the first and second positions;

 The polarization separation means,

 A first hologram element having a plate shape, which is arranged substantially parallel to each other, and selectively diffracts predetermined polarization components substantially equal to each other,

 A diffracted light beam that is incident on the first hologram element, diffracted by the first and second hologram elements, and emitted from the second hologram element;

 The angle formed by the light beam incident on the first hologram element, transmitted through the first and second hologram elements, and emitted from the second hologram element exceeds 0 °, And less than 15 °,

In the light beam incident on the first hologram element and diffracted by the first and second hologram elements, the light flux incident on each hologram element and the hologram element thereof The angle formed by the more diffracted light beams is more than 20 °. Polarized light separation element.

 (20) The image display device according to claim 5, further comprising:

 Each of the lenses has a first and a second fly-eye lens in which a plurality of minute lenses are arranged, and each of the minute lenses constituting the first fly-eye lens is a second fly-eye lens. An integrated lens for forming an image of the light emitting means on a corresponding minute lens of the minute lens constituting the eye lens;

 The image display device, wherein the light condensing means is a first fly-eye lens of the integral.

 (21) The image display device according to claim 5, wherein

 The diffracted light beam and the transmitted light beam are light beams whose polarization directions are orthogonal to each other,

 The image display device, wherein the polarization plane rotating means rotates the polarization direction of the incident light beam by about 90 °.

(22) At least a light source, a diffractive optical element having refractive index anisotropy, and a total reflection mirror arranged adjacent to the light source,

 A polarized light component (P wave or S wave) in one direction of the light emitted from the light source passes through the diffractive optical element, is reflected by the reflection mirror, and passes through the diffractive optical element again. Exits through

A component (S-wave or P-wave) that is substantially orthogonal to the outgoing light changes its propagation direction due to the diffractive action of the diffractive optical element and emits the diffracted wave from the diffractive optical element. And a predetermined wavefront of the diffractive optical element is formed such that the propagation directions of the reflected wave from the mirror and the total reflection mirror are substantially the same and the relative emission angles are different. Lighting device. (2 3) Light source and

 Diffractive optical element with refractive index anisotropy

 A total reflection mirror placed next to this

 In order to rotate the polarization direction of the reflected light from the total reflection mirror in a direction substantially perpendicular to the polarization direction of the emitted light, it is necessary to reduce the number of phase plates arranged in the optical path to the diffractive optical element. Also have

 The one-way polarization component (P wave or S wave) of the light emitted from the light source passes through the diffractive optical element and is reflected by the reflection mirror, and the phase plate and the diffraction plate Exits through the optical element,

 A component (S-wave or P-wave) that is substantially orthogonal to the outgoing light changes its propagation direction due to the diffractive action of the diffractive optical element and emits the diffracted wave from the diffractive optical element. A polarized wave illuminating device, wherein a predetermined wavefront of the diffractive optical element is formed such that propagation directions of the reflected wave from the mirror and the total reflection mirror are substantially equal and substantially parallel light flux. .

(24) The polarized light illumination according to claim 2, wherein the polarization directions of the diffracted wave from the diffractive optical element and the light wave reflected and emitted by the total reflection mirror are substantially equal. apparatus.

(25) The polarized light illuminating device according to claim 2, wherein the diffractive optical element is reflected by the total internal reflection mirror and substantially transmits the light wave transmitted through the phase plate. (26) Light source and

A set of diffractive optical elements having refractive index anisotropy and At least a phase plate for rotating the polarization direction of the incident light wave in a substantially right-angle direction is included as a component,

 The light emitted from the light source enters one diffractive optical element, and is transmitted or diffracted for each polarization component (P wave or s wave), and the diffracted wave enters the other diffractive optical element. Are diffracted and emitted,

 In a configuration in which a phase plate is arranged in one of the optical paths of the transmitted wave and the diffracted wave of a set of diffractive optical elements,

 A polarized light illuminating device characterized in that one set of diffractive optical elements is arranged so that a light flux transmitted or diffracted by one set of diffractive optical elements becomes a substantially parallel light flux.

(27) The inclination of the set of diffractive optical elements with respect to a plane in which the light wave incident surfaces of the set of diffractive optical elements are substantially parallel to each other and perpendicular to the optical axis of the light emitted from the light source. The polarized illumination device according to claim 5, wherein the angle is 45 ° or less.

(28) The polarized light illuminating device according to claim 5, wherein the polarization directions of the substantially parallel light beams emitted from the pair of diffractive optical elements are substantially equal.

(29) A diffractive optical element that transmits or diffracts outgoing light from the light source for each polarization component (P wave or S wave)

 Another set of diffractive optical elements that further diffracts the diffracted wave, and a phase plate disposed in one of the optical paths of the transmitted wave or the diffracted wave of the one set of diffractive optical elements are one. When it is a constituent unit,

A plurality of structural units each including the pair of diffractive optical elements and the phase plate are adjacent to each other. A polarized lighting device characterized by being arranged side by side.

(30) The polarized light illuminating device according to claim 9, wherein the light beams emitted from the plurality of constituent units are substantially parallel light beams and have substantially the same polarization direction.

(31) The polarized light illuminating device according to claim 8, wherein the phase plate has a function of rotating a polarization direction of an incident light wave in a substantially right-angle direction.

(32) The light wave incident surfaces of the pair of diffractive optical elements forming the plurality of constituent units are substantially parallel to each other, and

 9. The polarization illuminating device according to claim 8, wherein an inclination angle of the set of diffractive optical elements with respect to a plane perpendicular to an optical axis of light emitted from the light source is 45 ° or less.

(33) The diffractive optical element has a periodic structure formed using an optical medium having refractive index anisotropy,

 A refractive index distribution corresponding to the periodic structure is generated for one-way polarization component (P wave or S wave) of the incident light,

 This refractive index difference causes light diffraction and

 9. The device according to claim 1, wherein said component has a function of proceeding straight ahead with priority to a component (S wave or P wave) substantially orthogonal to said incident light. The polarized light illuminating device according to any one of the above.

(34) An optical element wherein the periodic structure of the diffractive optical element has a refractive index anisotropy. 13. The polarized light illuminating device according to claim 12, wherein the polarized light illuminating device is formed by inclination of an optical axis of a medium.

(35) The diffractive optical element is configured to include liquid crystals arranged uniformly, and

 13. The method according to claim 12, wherein a photopolymerizable monomer or a photo-crosslinkable liquid crystal polymer is added, and the direction of the molecular axis of the liquid crystal is fixed in response to light irradiation in the ultraviolet region. Polarized lighting device. (36) The polarized light according to any one of claims 1, 2, 5, and 8, wherein the diffractive optical element includes a structure formed by overlapping a plurality of different periodic structures. Lighting equipment.

(37) The polarized light illumination according to any one of claims 1, 2, 5, and 8, wherein the diffractive optical element includes a stacked structure of a plurality of diffractive optical elements having different periodic structures. apparatus.

(38) A first lens array configured by arranging a plurality of lenses on the polarized light illuminating device according to any one of claims 1, 2, 5, and 8, and a pair with the first lens array. A projection display device, comprising at least a combination of a second lens array, a light valve, and a projection optical system for enlarging and projecting an optical image on the light valve.

(39) The light beam from the light source is color-separated into three light beams having different wavelengths corresponding to R (red), G (green), and B (blue).

Diffracted light having different forming wavefronts for the light beams having different wavelengths A polarization illuminating device according to any one of claims 1, 2, 5, and 8 is configured using the optical element,

 A first lens array configured by arranging a plurality of lenses thereon, a second lens array paired with the first lens array, and

 Light knob and

 A projection display device, comprising at least a combination of a projection optical system for enlarging and projecting the optical image on the light valve.

(40) Light source and

 A liquid crystal element having a liquid crystal layer sandwiched between two opposing transparent insulating substrates having transparent conductive electrodes patterned to form pixels;

 Diffractive optical elements arranged on both sides of the liquid crystal element

 Is configured to include at least

 The light emitted from the light source enters one diffractive optical element and is diffracted, and approximately 1/2 of the amount of light incident on the diffractive optical element enters the liquid crystal element,

 Modulated for each pixel of the liquid crystal element,

 An image display device for displaying an image by an operation in which a propagation direction of light after passing through the other diffractive optical element varies according to the modulation degree.

(1) A liquid crystal element having a liquid crystal layer sandwiched between two opposing transparent insulating substrates equipped with transparent conductive electrodes that are patterned to form pixels

Fewer mirrors and diffractive optical elements arranged on one side of the liquid crystal element Is configured to include

 Light incident on the diffractive optical element due to external light is diffracted, passes through the liquid crystal element, is reflected by the mirror, passes through the liquid crystal element again, and is modulated for each pixel of the liquid crystal element.

 An image display device, wherein an image is displayed by an action in which the propagation direction of light after exiting the diffractive optical element varies according to the degree of modulation.

(4 2) Light source

 A liquid crystal element having a liquid crystal layer sandwiched between two opposing transparent insulating substrates each having a patterned transparent conductive electrode to form a pixel; and

 The mirror arranged on one side of the liquid crystal element

 Diffractive optical elements arranged on both sides of the liquid crystal element

 Is configured to include at least

 Light emitted from the light source is incident on one diffractive optical element and diffracted, and approximately 1/2 of the amount of light incident on the diffractive optical element is incident on the liquid crystal element, and is modulated for each pixel of the liquid crystal element.

 An image is displayed by an action in which the propagation direction of light after passing through the other diffractive optical element varies depending on the modulation degree.

 Light incident on the diffractive optical element due to external light is diffracted, passes through the liquid crystal element, is reflected by the mirror, passes through the liquid crystal element again, and is modulated for each pixel of the liquid crystal element.

 In a configuration in which image display is performed by an action in which a propagation direction of light after exiting the diffractive optical element varies depending on the modulation degree,

An image display device, wherein an image is displayed by selectively switching between the light source disposed inside and external light. (43) The diffractive optical element has a periodic structure formed by using an optical medium having a refractive index anisotropy, and converts the incident light into a polarized component in one direction (P wave or S wave). On the other hand, a refractive index distribution corresponding to the periodic structure is generated, and a component that generates light diffraction due to the difference in the refractive index and is substantially orthogonal to the incident light (S wave or P wave) The image display device according to any one of claims 1 to 3, wherein the image display device has a function of preferentially going straight ahead. (44) One of the diffractive optical elements has a function of diffracting the P wave of the polarization component of the incident light and preferentially traveling the S wave, and the other of the diffractive optical elements diffracts the S wave, The image display device according to any one of claims 3 to 4, wherein the image display device has a function of preferentially traveling a P wave straight. (45) The image display device according to claim 4, wherein the periodic structure of the diffractive optical element is formed by inclination of an optical axis of an optical medium having refractive index anisotropy.

(46) The diffractive optical element is configured to include liquid crystals arranged uniformly, and a photo-polymerizable monomer or a photo-crosslinkable liquid crystal polymer is added to the diffractive optical element to irradiate light in an ultraviolet region. The image display device according to claim 4, wherein the direction of the molecular axis of the liquid crystal is fixed.

(47) The method according to any one of claims 1 to 3, wherein an electric field applied to each pixel formed in the liquid crystal layer is controlled to modulate light incident on each pixel. The image display device as described in the above. (48) The image display device according to any one of claims 1 to 3, wherein the diffractive optical element includes a structure formed by overlapping a plurality of different periodic structures.

(49) The image display device according to any one of claims 1 to 3, wherein the diffractive optical element includes a stacked structure of a plurality of diffractive optical elements having different periodic structures. (50) The image display device according to any one of claims 1 to 3, wherein a color filter composed of red (R), green (G), and blue (B) is combined on one side of the liquid crystal element. An image display device characterized by comprising: (51) In the image display device according to any one of Claims 1, 3, and 10, the light emitted from the diffraction grating is divided into approximately two directions, and one is illuminated with the other for image display. An image display device and a lighting device, which are configured to be used for light.

(52) A liquid crystal element having a liquid crystal layer sandwiched between two opposing transparent insulating substrates each having a transparent conductive electrode which is provided with a "tanned" transparent conductive electrode and a liquid crystal element to form a light source and a pixel. One side has a diffractive optical element having refractive index anisotropy and a phase plate for rotating the polarization direction of the incident light wave in a substantially perpendicular direction, and is disposed on the other side of the liquid crystal element. At least a diffractive optical element having a refractive index anisotropy, and the emitted light from the light source is a polarization component (P wave or P wave) which is substantially equal to the diffractive optical element and the phase plate. Or S wave), is incident on the liquid crystal element, is modulated for each pixel of the liquid crystal element, and switches the other diffractive optical element according to the degree of modulation. An image display device characterized in that an image is displayed by an action in which the propagation directions of light after passing therethrough are different.

(53) The image display device according to any one of claims 1, 2, 3, 11, 12, and 13 has at least a magnifying optical system for enlarging and displaying an optical image from the image display device. A small-sized image display device characterized by comprising a small-sized image display device in combination with the above.

(54) a liquid crystal element that modulates the polarization direction of the incident light according to the applied voltage;

 A pair of first and second diffractions respectively disposed on both sides of the liquid crystal element for selectively diffracting a predetermined polarization component and transmitting a polarization component having a polarization direction orthogonal to the predetermined polarization component. An image display device comprising: an optical element;

 (55) The image display device according to claim 1, wherein

 The first diffractive optical element causes any one of a transmitted polarized light component and a diffracted polarized light component of the light flux incident from the outside to enter the liquid crystal element,

 The second diffractive optical element transmits a polarized light component transmitted through the second diffractive optical element and a polarized light component diffracted by the diffractive optical element in a light beam emitted from the liquid crystal element in directions different from each other. An image display device characterized by being configured to emit light.

 (56) The image display device according to claim 2, wherein

 And a light source,

The first diffractive optical element is configured so that the light beam from the light source emits the light. An image display device, wherein a polarization component transmitted through a folding optical element is incident on the liquid crystal element.

 (57) The image display device according to claim 2, wherein

 A light source disposed in a normal direction of the first diffractive optical element;

 The image display device, wherein the first diffractive optical element is configured to make a polarized light component of a light beam from the light source transmitted through the diffraction optical element incident on the liquid crystal element.

 (58) The image display device according to claim 2, wherein

 A light source disposed in a direction inclined from a normal direction of the first diffractive optical element;

 The first diffractive optical element is characterized in that a polarized light component of the light beam from the light source diffracted by the first diffractive optical element is incident on the liquid crystal element. Image display device. (59) The image display device according to claim 2, further comprising:

 Reflection means provided at a predetermined interval on the outer side of the first diffractive optical element;

 A light source for causing a light beam to enter the diffractive optical means from a direction inclined from a normal line of the diffractive optical element via a distance between the first diffractive optical element and the reflecting means;

 The first diffractive optical element transmits a polarized light component diffracted by the first diffractive optical element in a light beam incident from the light source and transmits through the first diffractive optical element incident from the reflecting means. An image display device, characterized in that a polarized light component to be incident is incident on the liquid crystal element.

(60) Modulates the polarization direction of the incident light according to the applied voltage Liquid crystal element,

 A diffractive optical element disposed on one side of the liquid crystal element for selectively diffracting a predetermined polarization component and transmitting a polarization component having a polarization direction orthogonal to the predetermined polarization component;

 An image display device, comprising: a reflection unit disposed on the other surface side of the liquid crystal element.

 (61) The image display device according to any one of claims 1 to 7, wherein the diffractive optical element has a periodic structure formed using an optical medium having a refractive index anisotropy. A difference in the refractive index corresponding to the periodic structure is generated for one of the polarization components of the wave and the S-wave. An image display device characterized in that it has a function of preferentially proceeding straight ahead for generally orthogonal components.

 (62) The image display device according to any one of claims 1 to 7, wherein one of the diffractive optical elements has a function of diffracting a P wave of a polarization component of incident light and preferentially traveling an S wave. An image display device, characterized in that the other of the diffractive optical elements has a function of diffracting an S-wave and preferentially traveling a P-wave straight.

 (63) The image display device according to claim 8, wherein

 An image display device, wherein the periodic structure of the diffractive optical element is formed by inclination of an optical axis of an optical medium having refractive index anisotropy. (64) The image display device according to claim 8, wherein

The diffractive optical element is configured to include liquid crystals arranged uniformly, and a photo-polymerizable monomer or a photo-crosslinkable liquid crystal polymer is added to the diffractive optical element. An image display device, characterized in that the direction of the molecular axis of the liquid crystal is fixed. (65) The image display device according to any one of claims 1 to 7, wherein the diffractive optical element includes a structure formed by overlapping a plurality of different periodic structures. .

 (66) The image display device according to any one of claims 1 to 7, wherein the diffractive optical element includes a laminated structure of a plurality of diffractive optical elements having different periodic structures. .

 (67) The image display device according to claim 1 or claim 7, further comprising a color filter in which red, green, and blue regions are formed on one side of the liquid crystal element. An image display device characterized by having an evening.

 (68) The image display device according to claim 1 or claim 7, further comprising:

 An image display device comprising an enlargement optical unit for enlarging and displaying a display image.

(69) A liquid crystal element having a liquid crystal layer sandwiched between two opposing transparent insulating substrates each having a transparent conductive electrode patterned to form a light source and a pixel, and one side of the liquid crystal element. It has a diffractive optical element having refractive index anisotropy and a phase plate for rotating the polarization direction of the incident light wave in a substantially perpendicular direction, and further has a refractive index anisotropy disposed on the other side of the liquid crystal element. And a diffracting optical element having at least a polarization component (P-wave or S-wave), wherein the light emitted from the light source is substantially equal to the polarization component by the diffractive optical element and the phase plate. The light is then incident on the liquid crystal element, is modulated for each pixel of the liquid crystal element, and the image display is performed by the effect that the propagation direction of the light after passing through the other diffractive optical element differs according to the degree of modulation. An image display device characterized by performing the following. (70) a laser emitting polarized light, an optical lens for converging a laser beam emitted from the laser on an optical storage medium, and a laser beam reflected by the optical storage medium in a direction of polarization. A phase plate for rotating the light in a direction substantially perpendicular to the polarization direction of the light, a diffractive optical element arranged in the optical path of the reflected light to generate a predetermined wavefront, and detecting light diffracted by the diffractive optical element A diffractive optical element used in an optical information processing device having at least a light receiving element for performing the operation, wherein the diffractive optical element is formed using an optical medium having a refractive index anisotropy. And the ratio of the amount of light that is reflected by the optical recording medium and diffracted in the primary direction to the total amount of laser light after passing through the diffractive optical element is approximately 1/2 or more. A predetermined wavefront is formed Diffractive optical element to feature a call that.

(71) Having a periodic structure in the thickness direction, a refractive index distribution corresponding to the periodic structure is generated for the polarized light component in one direction of the incident light, and light is diffracted by this refractive index difference. 2. The diffractive optical element according to claim 1, wherein the diffractive optical element has a function of causing the light to travel straight ahead preferentially with respect to a component orthogonal to the polarization component of the incident light. (72) A periodic structure in a thickness direction, wherein the periodic structure is formed by inclination of an optical axis of an optical medium having a refractive index anisotropy. 2. The diffractive optical element according to 2.

(73) A photopolymerizable liquid crystal monomer or a photocrosslinkable liquid crystal polymer, which is composed of uniformly arranged liquid crystals, is added, and the liquid crystal is exposed to light in the ultraviolet region. Characterized in that the direction of the molecular axis is fixed The diffractive optical element according to claim 2, wherein

(74) The diffraction according to claim 1, wherein the polarization direction of the laser light incident on the diffractive optical element is substantially parallel or perpendicular to the optical axis of the optical medium having the refractive index anisotropy. Optical element.

(75) An optical medium having a refractive index anisotropy is sealed in a region sandwiched between the transparent insulating substrates having two opposing transparent conductive electrodes, and a polymer is formed on the transparent conductive electrodes. A method for manufacturing a diffractive optical element having a structure in which a thin film having been subjected to an orientation treatment is formed, the method comprising: causing light split into two in an ultraviolet wavelength region to interfere on the diffractive optical element; A first step of generating an interference fringe composed of a bright portion and a dark portion corresponding to an intense intensity distribution, and fixing the optical axis of the optical medium in a region belonging to the bright portion of the interference fringe in the direction of the initial orientation; An electric field is applied between the conductive electrodes, and the optical axis of the optical medium in a region belonging to the dark portion of the interference fringes is moved from the direction in which the optical alignment was initially aligned. The second step of fixing the optical axis direction by performing light irradiation Method for manufacturing a diffractive optical element characterized and whatever child. (76) The method for manufacturing a diffractive optical element according to claim 6, wherein the electric field applied to the diffractive optical element comprises an alternating electric field in which a positive electrode and a negative electrode are alternately generated.

(77) An optical medium having a refractive index anisotropy is sealed in a region sandwiched between two opposing transparent insulating substrates, and an alignment process comprising a polymer is performed on the transparent insulating substrate. Diffraction having a structure with formed thin film A method for manufacturing an optical element, comprising:

 The light split into two in the ultraviolet wavelength range is caused to interfere on the diffractive optical element to generate an interference fringe composed of a bright part and a dark part corresponding to a periodic intensity distribution, and to generate an interference fringe in an area belonging to the bright part of the interference fringe. A first step of fixing an optical axis of the optical medium in a direction in which the optical medium is initially oriented; and applying a magnetic field between the transparent insulating substrates to initially set an optical axis of the optical medium in a region belonging to a dark portion of the interference fringes. A second step of fixing the direction of the optical axis by irradiating the entire surface of the diffractive optical element with light in a uniform ultraviolet region while moving the diffracted optical element from the initially oriented direction. A method for manufacturing a diffractive optical element.

(78) A structure in which an optical medium having refractive index anisotropy is sealed in a region sandwiched between two opposing transparent insulating substrates, and a thin film made of a polymer is formed on the transparent insulating substrate. A method for manufacturing a diffractive optical element having

 The two-divided light in the ultraviolet wavelength region having a polarized component in one direction is caused to interfere on the diffractive optical element, and an interference fringe consisting of a bright portion and a dark portion corresponding to a periodic intensity distribution is generated. A first step of arranging and fixing the optical axis of the optical medium in a region belonging to the bright portion of the optical element in a uniform direction depending on the polarization direction of the polarization component, and the polarization component on the entire surface of the diffractive optical element A second step of moving and fixing the optical axis direction of the optical medium from an initial position by irradiating light in a uniform ultraviolet region having a polarization direction in a direction substantially perpendicular to the optical medium. A method for manufacturing a diffractive optical element, comprising:

(79) The optical medium having the refractive index anisotropy is composed of liquid crystals arranged uniformly, and is capable of photopolymerizable liquid crystal monomer or photocrosslinking. 7. A liquid crystal polymer is added,

10. The method for producing a diffractive optical element according to any one of 8 and 9.

(80) The interference fringe applied to the diffractive optical element is a highly dry light source composed of a He—Cd laser or an Ar laser, and is from 300 nm to 40 O nm. 10. The method for manufacturing a diffractive optical element according to claim 6, wherein the wavelength range is within the range described above.

(81) The method according to any one of claims 6, 8, and 9, wherein the formation of the periodic structure by irradiating the diffractive optical element with light is performed a plurality of times for each divided region on the surface of the diffractive optical element. A method for producing the diffractive optical element according to any one of the above.

(82) By irradiating light to the diffractive optical element a plurality of times, different periodic structures are formed in the diffractive optical element so as to overlap with each other. 10. The method for producing a diffractive optical element according to any one of claims 9 and 9.

(83) At least an image display means, and an illumination means for illuminating the image display means, wherein the image display means modulates and outputs illumination light from the illumination means incident on the image display means. The illumination means includes at least a light emitting means, a first light condensing means for condensing an output light flux of the light emitting means, and an output light flux of the first light condensing means. First wavefront converting means for converting the wavefront of the first light beam, wherein the first wavefront converting means comprises a first light beam substantially equivalent to the wavefront of the output light beam from the first light condensing means, and a second lightfront. An image display device, which is a first holographic element formed by interfering a light beam. (84) the lighting means, a first condensing means for condensing an output light flux of the light emitting means, a second condensing means for propagating an output light flux of the first condensing means, A second wavefront converting means for converting a wavefront of an output light beam from the second condensing means, wherein the second wavefront converting means is substantially equivalent to a wavefront of the output light beam of the second condensing means. 2. The image display device according to claim 1, wherein the image display device is a second hologram element formed by interfering a first light beam and a third light beam.

 (85) The illuminating means has an integrator composed of first and second fly-eye lenses in which a plurality of lenses are arranged in a two-dimensional array. The image display device according to claim 1 or 2, wherein:

 (86) The image display means is a polarized light display means, and the polarized light display means separates the polarized light, which is deflected in a substantially specific direction, from the incident illumination light from the illumination means, The image display device according to any one of claims 1 to 3, wherein an image is displayed by modulating the polarized light.

 (87) The image display device according to any one of claims 1 to 4, wherein the illuminating means includes a polarization converting means for converting the randomly polarized light into polarized light having a substantially specific direction.

 (88) The image display device according to any one of claims 2 to 5, wherein the final output means of the second light focusing means is the first fly's eye lens.

(89) The second or third luminous flux is an output luminous flux from a small luminous body having a smaller volume than the luminous body of the luminous means, or a luminous flux obtained by reflecting the output luminous flux with a reflecting mirror. Or being substantially equivalent to the wavefront of the output light beam or the light beam transmitted by the third focusing means. The image display device according to any one of claims 1 to 6, wherein

 (90) The second light beam or the third light beam is substantially equivalent to a substantially plane wave or a wavefront of a light beam obtained by propagating the substantially plane wave by the third focusing means. The image display device according to claim 1, wherein the image display device is a light beam having a wavefront.

 (91) The final output means of the second light focusing means is the first fly-eye lens, and the final output means of the third light focusing means is the third fly-eye lens. The method according to any one of claims 2 to 8, wherein the third fly-eye lens and the second fly-eye lens form an integral set of pairs. Image display device.

 (92) The image display device according to any one of claims 1 to 9, wherein the reflecting mirror is a paraboloid of revolution, a spheroidal mirror, or a spherical mirror.

 (93) The polarization conversion element includes at least a polarization separation unit and a polarization plane rotation unit, and one of the polarization planes substantially orthogonal to each other separated by the polarization separation unit. The image display device according to any one of claims 1 to 10, wherein the polarization plane rotation means is configured to rotate the polarization plane by approximately 90 °.

(94) The hologram element is a hologram element that forms an interference fringe formed by interfering two light beams, a reference light beam generated by the reference light beam generation means and an object light beam generated by the object light beam generation means. The reference light beam is generated by making one of the two laser beams produced by recording on a material and incident on the reference light beam generating means, and the laser light beam is divided into two. A hologram element, the other being incident on the object conflict generating means to generate the object light beam. (95) The reference light beam generating means further comprises at least a reflecting mirror and a small-sized first reflector that is stationary at a predetermined position, and reflects one of the two divided laser beams. The first reflector is illuminated by being incident on one or a plurality of transmission holes provided in a mirror, and the reflected or scattered light flux from the first reflector and the reflected light are illuminated. 13. The method for manufacturing a holographic element according to claim 12, wherein either the scattered light beam reflected by the reflecting mirror or both light beams are used as the reference light beam.

 (96) The object light beam generating means is provided with at least a reflecting mirror and a second reflecting body which is settled at a predetermined position, and one or more of the object light beam generating means provided on the reflecting mirror. The second reflector is illuminated by being incident on a plurality of transmission holes, and the reflected or scattered light flux from the second reflector and the reflected or scattered light flux are reflected by a reflector. A method of manufacturing a hologram element, wherein either one of the light fluxes reflected again in step (b) or both are used as the object light flux, wherein the shape of the second reflector is 13. The method according to claim 12, wherein the shape of the luminous body of the luminous means used in the image display device is substantially the same.

 (97) By increasing or decreasing the size of the second reflector a plurality of times, a different object light beam is generated a plurality of times, and a plurality of the object light beams are generated. The method according to any one of claims 12 to 14, wherein the reference light beam is dried and the hologram material is multiplex-recorded.

 (98) The hologram element according to claim 12 or 13, wherein the object light beam generating means is a divergent light beam generating means for outputting one incident laser light beam within a specific angle of erection. Manufacturing method.

(99) The output light beam of the divergent light beam generation means is substantially equal to the light beam incident on the hologram element in the image display device. The method for manufacturing a hologram element according to any one of claims 12, 13, and 16.

 (100) Either one or both of the divergent light beam generating means and the object light beam generating means, or one or more of a plurality of converging lenses and an integral lens 18. The method for manufacturing a hologram element according to claim 12, wherein the method includes both of them.

 (101) Either one or both of the reference light beam generating means and the object light beam generating means is a hologram in which the reference light beam or the object light beam is recorded. The method for producing a holographic element according to any one of claims 12 to 18, characterized in that:

 (102) The reference beam and the object beam are generated using a plurality of laser beams having different wavelengths, and a plurality of two-beam interference fringes formed at different wavelengths are applied to the hologram material. The method for producing a hologram element according to any one of claims 12 to 19, wherein multiplex recording is performed.

(1 0 3)

A hologram element formed by interfering an object light and a reference light, wherein the object light is a substantially parallel light flux (hereinafter, simply referred to as an object light flux), and the reference light is emitted from a light emitting unit. A hologram element characterized in that the hologram element is a light beam having a wavefront substantially equivalent to an output light beam from an illuminating means for condensing and transmitting the light beam (hereinafter, abbreviated as a reference light beam). (1 0 4)

 The illuminating means includes a condensing means for condensing at least the first light flux, and a plurality of lenses for transmitting the second light flux condensed by the condensing means in two dimensions. 2. The hologram according to claim 1, further comprising an integrated lens that combines a first fly-eye lens and a second fly-eye lens arranged in an array. Element.

(1 0 5)

 The illuminating means includes: polarization separating means for separating an incident light beam into components whose polarization planes are orthogonal to each other; and a polarization plane rotation for rotating the polarization plane of one of the separated polarization components by approximately 90 degrees. The hologram element according to claim 1 or 2, further comprising a means.

(1 0 6)

 The hologram element according to any one of claims 1 to 3, wherein the hologram element is provided with a reflection mirror on a back surface after creating an interference draft.

(1 0 7)

 The hologram element according to any one of claims 1 to 4, wherein the reflection mirror selectively reflects a light beam in a specific wavelength band.

(1 0 8)

At least the hologram element, the illuminating means for illuminating the hologram element, and a light source for modulating an output light beam of the hologram element. And an image display means for displaying an image with the image display means. The image display means includes a micro lens corresponding to each pixel. An image display device having a function of converging light into an opening portion of the image display device.

(1 0 9)

 The illuminating means includes color separation means for separating a white incident light beam into three primary colors having a unique wavelength band, and the object light beam having a wavelength included in a wavelength band of a specific primary color among the three primary colors. The image display device according to claim 6, wherein the output light beam of the hologram element created by the reference light beam is an incident light beam of the image display means for displaying an image signal of a corresponding primary color.

(1 1 0)

 The color separation means is a dichroic mirror that selectively reflects three primary colors of a specific wavelength band, and is provided on a light incident side of each dichroic mirror. The hologram element formed by the object light beam and the reference light beam having a wavelength included in the wavelength band that the corresponding dichroic mirror selectively reflects. The image display device according to claim 6, wherein the image display device is characterized in that:

(1 1 1)

At least the hologram element, the illumination means for illuminating the hologram element, and an image display means for displaying an image by modulating an output light flux of the hologram element. That is, the image display means displays only an image signal of a corresponding primary color from among the three primary colors. An image display device characterized by having a pixel structure in which one pixel is a set, and having an optical path changing means corresponding to the one pixel structure.

(1 1 2)

 The illuminating means includes at least a color separating means, and the color separating means is a dichroic mirror for selectively reflecting three primary colors of a specific wavelength band, In addition, on the light incident side of each dichroic mirror, the corresponding dichroic mirror is formed by the object light flux and the reference light flux having a wavelength included in the wavelength band that is selectively reflected. A hologram element is arranged, and the inclination angle of each dichroic mirror with respect to the optical axis of the illumination optical system is made different so that the light enters the image display means for each of the three primary colors. The optical path changing means formed in the image display means, corresponding to the primary colors incident from different directions by the hologram element and the die-cloth mirror, respectively. Only primary color image signal The image display apparatus according to claim 9, featuring that you have a Shi was generally focused on the opening of each pixel to be displayed Mel functions.

(1 1 3)

 10. The image display device according to claim 9, wherein the optical path changing means is any one of a micro lens array, a diffractive optical element, and a cylindrical lens.

(1 1 4)

A diffractive optical element comprising a plurality of minute regions, wherein an output light beam of the minute region has a plane crossing a normal direction of the diffractive optical element at a predetermined angle. A diffractive optical element characterized in that the light beams substantially overlap each other on a plane.

(1 1 5)

 The diffractive optical element is a hologram composed of a plurality of minute regions created by interfering the object light and the reference light, and the object light of the plurality of minute regions is a normal direction of the hologram and 2. The diffractive optical element according to claim 1, wherein the light beams substantially overlap each other on a plane intersecting at a predetermined angle.

(1 1 6)

 3. The diffractive optical element according to claim 1, wherein the shape in which the object light beams of the respective minute regions substantially overlap each other on the plane is a rectangle. 4.

(1 1 7)

 4. The diffractive optical element according to claim 1, wherein the reference light is a substantially parallel light beam incident on the hologram at a predetermined angle.

(1 1 8)

 4. The diffraction device according to claim 1, wherein the reference light is convergent light that is substantially converged at one point on an optical axis that intersects the hologram at a predetermined angle. 5. Optical element.

(1 1 9)

At least the diffractive optical element, and illuminating the diffractive optical element Illuminating means, and image display means for displaying an image by modulating the output light flux of the diffractive optical element, wherein the output light fluxes of the diffractive optical element substantially overlap each other on the image display means. An image display device, wherein the shape of the output light fluxes that overlap each other is a rectangle having a size substantially equal to the image display area of the image display means.

(1 2 0)

 The image display means includes a micro lens corresponding to each pixel, and the micro lens has a function of converging an incident light beam to an aperture portion of the pixel. The image display device according to claim 6, wherein:

(1 2 1)

 The normal line of the diffractive optical element is not parallel to the optical axis of the illuminating means, and the area where the output light beam from the illuminating means illuminates the diffractive optical element is substantially elliptical, 8. The image display device according to claim 6, wherein a major axis direction substantially coincides with a longitudinal direction of an image display area of the image display means.

(1 2 2)

 9. The image according to claim 6, wherein the illuminating means includes a polarization separating means and a polarization plane rotating means having a function of aligning a polarization direction of a non-polarized light beam in a specific direction. Display device.