KR20010031135A - Hologram element polarization separating device, polarization illuminating device, and image display - Google Patents

Abstract

In order to effectively exhibit the function of effectively increasing the aperture ratio of the microlens array formed in the image display element, and to construct a bright image display device having high uniformity and high projection efficiency, the object light and the reference light are interfered. A hologram element which is a reference light beam which is created and whose object light is a substantially parallel object light beam, and the reference light has a wavefront which is substantially equivalent to the output light flux of the lighting means for condensing and propagating the first light beam emitted from the light emitting means. Means for illuminating the hologram element, and image display elements 6 to 8 for displaying an image by modulating the output luminous flux of the hologram element, wherein the image display element corresponds to each pixel. And a microlens having a function of converging the incident light flux into the openings of the pixels. do.

Description

HOLOGRAM ELEMENT POLARIZATION SEPARATING DEVICE, POLARIZATION ILLUMINATING DEVICE, AND IMAGE DISPLAY}

The development of a projection type image display apparatus which luminance-modulates light by an image display element and enlarges and projects it on a screen (for example, Oprasui, August 1993, pages 58-101).

Fig. 1 is a conventional general image display apparatus, and shows a structural example using a liquid crystal panel as image display means. Reflects the output light 3 from the lamp 2 to the reflector 4, condenses and propagates the output light beam 5 by a condensing optical system (not shown), and dichroic for color separation. The dichroic mirrors 12 and 13 are separated into three primary colors of red, green, and blue, and are incident on the liquid crystal panels 16 to 18 through the total reflection mirror 14 and the condenser lens 15.

The output light modulated by the liquid crystal panels 16 to 18 is synthesized by a dichroic prism (not shown) or dichroic mirrors 19 and 20 and a total reflection mirror 14 for color synthesis. Is projected on a screen (not shown).

Although the liquid crystal panels 16 to 18 are mainly classified into a transmissive type and a reflective type, the liquid crystal material receives specific linearly polarized light incident through a polarizing plate or a polarizing beam splitter (hereinafter referred to as PBS) by a liquid crystal material. The image is displayed by modulating.

In general, the liquid crystal panels 16-18 are switching elements for driving each pixel, and an active matrix system in which thin film transistors (hereinafter referred to as TFTs) are disposed in each pixel is mainly used, and TFTs are formed of polycrystalline polysilicon. It is common to be.

Moreover, the structural example of another conventional general image display apparatus is shown in FIG. After reflecting the output light from the lamp 22 to the reflector 23, an integrator consisting of the first fly's eye lens 24 and the second fly's eye lens 25, the folding mirror Propagation is carried out by (29), and separated into three primary colors of red, green, and blue by dichroic mirrors 30 and 31 for color separation, and incident on the image display elements 35 to 37.

The image display elements 33 to 35 are largely classified into a transmission type that modulates the incident light flux through the image display element and a reflection type that modulates the incident light flux after reflection and output. Moreover, as a modulation method, it is largely divided into the polarization type which changes the polarization state of an incident light beam, and the scattering type which modulates by scattering an incident light beam.

In the image display element of the polarization type, both the transmissive type and the reflective type use an image by modulating specific linearly polarized light incident through a polarizing plate or a polarizing beam splitter (hereinafter referred to as PBS) with, for example, a liquid crystal material. Is displayed. In the scattering type image display device, both the transmission type and the reflection type display black by scattering the incident light beam, and white by displaying the light without scattering the incident light beam.

In Figs. 1 and 2, a configuration using three image display elements (hereinafter referred to as a three-plate type) is used, but there is also a method of displaying color images with one image display element (hereinafter referred to as a single plate type) as described later.

As the lamp 2 or the like, a lamp having high luminous efficiency, a small volume of the light emitting body, high brightness and high color rendering property is obtained, and a metal halide lamp, xenon lamp, and ultrahigh pressure Mercury lamps are used.

As the reflector 3 or the like, it is easy to effectively use the light beam after reflection, and thus, a spectacle mirror, an ellipsoid mirror, a spherical mirror, or the like is used, and the light emitting body is disposed at the focal point or the first focal point or center of the reflector. There are many.

In a recent image display apparatus, when displaying a full white signal,

(1) Make the brightness of the center of the projection image and the brightness of the periphery uniform.

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

(1) by introducing an integrator, (2) by integrating the integrator with a high-brightness lamp with a small light emitter or as an image display means. In the image display apparatus using the same polarization display means, a solution can be tried by assembling the polarization conversion element. In addition, the improvement of the projection efficiency by forming a microlens in a liquid crystal panel is also examined a lot.

Next, the integrator will be described. As an integrator, as disclosed in Japanese Patent Laid-Open No. 3-111806 and Japanese Patent Laid-Open No. 5-346557, for example, two types of fly-eye lenses formed by arranging microlenses in two dimensions are assembled. It is configured by. 4 shows a specific configuration example of the integrator. This divides the output light flux from the light source into a plurality of regions, and stacks them on the object to be illuminated to improve uniformity with the illumination light.

The output light beam of the lamp 42 is reflected by the reflector 43 and then enters the first fly's eye lens 44. By means of the reflector 43 and the first fly's eye lens 44, the image of the luminous body of the lamp 42 is the second fly's eye lens corresponding to each lens of the first fly's eye lens 44. It forms on each lens of 45. FIG. Each lens of the second fly's eye lens 45 is configured to form an image of each lens constituting the first fly's eye lens 44 on the image display element 47. In addition, although a relay lens and an auxiliary lens are disposed between the second fly's eye lens and the image display element as necessary, the basic function as an integrator does not change.

According to the above configuration, an image in which each lens of the second fly's-eye lens 45 forms an image on the image display element 47 has a large output light flux of the luminance distribution output from the reflector 43. It is a result of dividing | segmenting by each lens of 44, and superposing | polymerizing on the image display element 47. By this principle, it is possible to increase the brightness of the peripheral portion with respect to the image center portion in the projected image to 70% or more.

In addition, the introduction of the integrator can also improve the projection efficiency of the image display apparatus. In general, although the light beam reflected by the reflector 43 is almost circular, the image display element 37 is, for example, a rectangle of 4: 3 (or a rectangle of 16: 9). Therefore, when illuminating the image display element 47 circularly, only the rectangular area ratio inscribed in the circle was effectively utilized. This is called a square conversion efficiency, and the square conversion efficiency was about 61% when using the image display element 47 whose aspect ratio was 4: 3 (outside aspect ratio).

However, by arranging the aperture shape of the lens used for the first fly's eye lens 44 of the integrator as 4: 3, as disclosed in Fig. 2 of Japanese Patent Application Laid-open No. Hei 5-346557, It is possible to improve to 80%.

However, as shown in FIG. 2 of Japanese Patent Laid-Open No. 5-346557, the aperture shape of the lens used for the first fly's eye lens 4 of the integrator is 4: 3, for example, as an image display element. In addition to making the shape similar to the shape of, the lens of the first fly's eye lens is closely formed in the circular illumination area, it is possible to improve the square conversion efficiency to about 80%.

Next, the polarization conversion element will be described. In the image display apparatus using the above-mentioned polarizing liquid crystal panel, there is a drawback that only the polarization component in a specific direction can be effectively utilized among the output light of the lamp. In order to obtain a bright image with low projection efficiency, a light source having a large output is used. The problem is that it must be used. A polarization converting element has been developed for the purpose of solving such a problem, and the polarization component which is absorbed by the polarizer or reflected by PBS and is not incident on the liquid crystal panel is effectively used as a polarization component having a polarization plane which is substantially orthogonal to the polarization component. To convert.

Examples of polarization conversion devices include Japanese Patent Application Laid-Open No. 5-107505, Japanese Patent Application Laid-Open No. 6-202094, Japanese Patent Application Laid-Open No. 7-294906, Japanese Patent Application Laid-Open No. 8-234205, and Japanese Patent Publication Although many are disclosed in Japanese Patent Application Laid-Open No. 9-105936 and the like, basically, a combination of polarization separation means and polarization plane rotating means is employed.

3 shows a configuration diagram of a general polarization conversion element 38. The polarized light component (random polarized light beam) 62 has polarization components orthogonal to each other by the polarization separation means 60, that is, P polarization light (polarized light polarization separation means) having a polarization direction parallel to the ground that is transmitted without being reflected by the polarization separation means. Light beam) 63`, and the S polarized light (the light beam reflected by the polarized light separating means and having a polarization direction perpendicular to the ground) 64, and only the S polarized light 64 is the reflecting means 60 (generally It is based on the principle of reflecting by the polarization splitting means 60 and using the same kind of film) and converting it into P-polarized light 41 'by the polarization plane rotating means 61.

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

Next, a liquid crystal panel in which microlenses are formed will be described. In a typical image display element, a TFT for driving a pixel is formed for each pixel, and therefore, a portion of the pixel that forms the TFT cannot transmit light. That is, there is a drawback that the area ratio (opening ratio) that light can actually transmit to the area of each pixel is small.

This is more remarkable in a high resolution image display device. In an image display device in which 1024 x 768 pixels are formed in a diagonal 1.3 inch panel, the aperture ratio is about 56%, and the same number of pixels are formed in a 0.9 inch diagonal image display device. In one case it is only about 40%. If the resolution is increased by increasing the number of pixels, or the image display element is made small even if the number of pixels is the same, the aperture ratio is markedly lowered, and as a result, the projection efficiency is lowered.

By the way, for example, as disclosed in many reference examples such as Japanese Patent Application Laid-Open No. 1-281426, Japanese Patent Application Laid-Open No. Hei 3-140920, and Japanese Patent Application Laid-Open No. 4-251221, the glass on the incidence side It is thought to improve the effective aperture ratio by forming a microlens on a (class) substrate, and condensing incident light only to an opening (a portion through which light can pass) in each pixel. It is done.

Moreover, a single plate type image display apparatus using a single image display element has also been developed. Since the single plate type has fewer image display elements than the three plate type, and the structure of the optical system is simplified, it is possible to realize a low cost for the practical use of the image display device. In addition, it is possible to expect such effects as weight reduction of the set and unnecessary color convergence.

Color convergence means, for example, in the three-plate type, that the output of the corresponding pixel of each image display element is positioned on the screen, and that a large amount of time is required for the increase and adjustment of the score of the mechanical component for the alignment. It is a factor of the cost up by the back.

On the other hand, the single plate type has a drawback that the projection efficiency is lower than that of the three plate type. For example, in the case where the color filter is provided inside, there is a drawback that, in principle, the light intensity becomes 1/3, resulting in a dark image. This is because the three-plate type can be used without almost absorbing the three primary colors, and the color filter transmits only the light flux of a specific wavelength band and does not input to a pixel that absorbs or reflects light of another wavelength band. .

By the way, for example, Nikkei Electronics, January 30, 1995, page 169, page 173 (hereinafter referred to as Reference Example 1), Japanese Patent Application Laid-Open No. 8-292506 (hereinafter referred to as Reference Example 2), and Japanese Patent Figure 14 (hereinafter referred to as Reference Example 3) of Japanese Patent Application Laid-Open No. 9-105899, Nikkei Electronics, October 21, 1996, page 18, page 19 (a) of Figure 4 (hereinafter referred to as Reference Example 4), As disclosed in Japanese Unexamined Patent Publication No. 6-222361 (hereinafter referred to as Reference Example 5) and the like, it is possible to improve the projection efficiency by separating white light into three primary colors and then injecting each of the primary colors into corresponding pixels. It is proposed.

Both of the above reference examples consist of color separation means for separating white light into three primary colors, and optical path changing means for injecting the light beam after separation into corresponding pixels. As the color separation means, dichroic mirrors (hereinafter referred to as bi-diagonal dichroic mirrors) arranged at different angles with respect to the optical axis are often used as disclosed in Reference Examples 1, 2, and 3, As the optical path changing means, a micro lens array (reference example 1), a hologram lens array (reference example 2), a cylindrical lens (reference example 3), and the like are used.

For example, as disclosed in Reference Examples 4 and 5, color separation means and optical path changing means may be used in combination using diffractive optical elements such as hologram elements.

However, the above conventional image display apparatus has the following problems.

In order to effectively utilize the functions of the integrator and the polarization conversion element, it was necessary to use a small high brightness lamp of the luminous body. The reason for this is briefly described below. In the integrator, each of the lenses constituting the first fly's eye lens (hereinafter referred to as the first lens group) is a light emitter in each lens (hereinafter referred to as a second lens group) corresponding to the second fly's eye lens. In this case, when an image larger than the opening of the second lens group is formed, a luminous flux that does not effectively propagate to the image display means is generated, resulting in a loss of projection efficiency. Therefore, the smaller the light emitter is, the smaller the above-mentioned loss is, so that the integrator can be effectively functioned.

The above phenomenon is the same even when the polarization display means is not used as the image display means, for example, when the polymer dispersed liquid crystal panel or the light deflecting image display means disclosed in US Patent No. 5096279 is used. .

In addition, in the polarization conversion element, for example, in the case of being configured by a combination with an integrator (practically most examples), the light beam must be focused only on the polarization separating means as in the case of the integrator described above. . For example, in the polarization splitting element 58 shown in FIG. 14, the light is incident on the reflecting means 60 ′ provided with the polarization splitting means 61 and not the polarization splitting means 60. Is not effectively used and is lost.

The same applies to the case where the polarization conversion element is arranged on the lamp side of the first fly's eye lens and the irradiation angle after polarization separation is changed by the polarization component, in this case before or after the second fly's eye lens. Only a specific polarization component must be incident on the polarization plane rotating means provided later. Therefore, in order to improve the efficiency of the polarization conversion element and further improve the projection efficiency, a lamp having a small light emitting body is required.

For example, when a single polarization conversion element is irradiated with parallel light such as laser light and the efficiency thereof is irradiated, for example, in the case of the element shown in Fig. 14, the transmittance of the P-polarized light 63 is about 96 % And the efficiency at which the S-polarized light 64 is incident on the polarization splitting device 58 and then converted into the P-polarized light 63 by the polarization plane rotating means 61 is about 91%, which has extremely high performance. The efficiency at which the unpolarized light 62 is converted to the P polarized light 63 is about 94%. In the image display apparatus using the polarization display means, this efficiency can be defined as the polarization utilization efficiency. However, even when a lamp having a small length of light emitter is actually about 1.45 millimeters, the polarization utilization efficiency is lowered to less than about 80%, and a lamp having a length of light emitter is about 3 millimeters, but preferably about 60%, The large difference in the polarization utilization efficiency of 50% in the absence of the polarization conversion element is due to the size of the light emitting body of the lamp described above.

In addition to the above reason, a light source with a small light emitter is required even in combination with a reflector for effectively collecting the output light from the lamp. For example, the case where a mirror mirror is used as a reflector is considered. This parabolic mirror has a concave surface formed by rotating a parabolic wire by a rotation axis coinciding with the optical axis as a reflection surface. In general, the light emitter is provided near the focal point of the object line on the optical axis. This is because the light beam emanating from the focal point of the radiation line becomes parallel rays after reflection on the surface.

However, since the actual light emitter of the lamp has a finite size rather than a dot, condensed light and divergent light are generated, resulting in loss. Even for this reason, a small lamp having a light emitter was indispensable. As a result, it is considered that by using a lamp whose light emitter is extremely small and regarded as a point light source, extremely high projection efficiency can be realized by utilizing the inherent functions of the integrator and polarization conversion element described above.

As described above, the performance of the integrator and the polarization conversion efficiency of the polarization conversion element are much more affected by the size of the light emitter, but this becomes an important problem when displaying a higher brightness image. For example, if the light is about 100 to 200 watts, the size of the light emitting body is only about 2 millimeters, and it is somewhat satisfactory as a function of the integrator and the polarization conversion element as described above. It becomes big with increase.

Therefore, a high projection efficiency of 6 lumens / watt is possible in an image display apparatus using a low power lamp of about 100 to 200 watts, but only a high 3 lumens / watt can be realized when a high power lamp of more than that is used.

In the end, an image display device having a light output of 600 lumens in total of 6 lumens / watt using a 100 watt lamp may be realized. For example, an image display device having a light output of 1200 lumens using a 200 watt lamp may be realized. Realization was difficult. As mentioned above, the projection efficiency was remarkably lowered when the projection light flux was increased by using a high output lamp.

In the combination of the integrator and the polarization conversion element, the development of a high brightness lamp with a small light emitter has made it possible to realize high projection efficiency in recent years. However, when the integrator and the image display element in which the microlens is formed are combined, or the image display element in which the microlens is formed in addition to the integrator and the polarization converting element are combined, the aperture ratio of the effective image display assistant is reduced. There was a problem that even if you try to improve, you can not get great effect. The reason is briefly described below.

Initially, in order to increase the effect of the effective aperture ratio improvement by the microlenses, it is preferable that the incident light beam into the microlenses is substantially parallel to the optical axis. This is because the luminous flux obliquely incident on the optical axis of the microlens is incident on portions other than the opening of the pixel.

Although the luminous body condenses the luminous flux of a small high-brightness lamp with a plane mirror, an almost luminous flux can be obtained. However, in the actual illumination optical system, it is necessary to use the integrator or polarization conversion element described above. The luminous flux incident on the device, i.e., the microlens, is not nearly parallel luminous flux.

Therefore, although ideally, the effective aperture ratio can be almost 100%, in the above example, even when the microlenses are introduced, only an improvement of the aperture ratio of 1.2 times can be expected, and it is effective in a diagonal 1.3 inch image display element. A typical aperture ratio of 67% and a diagonal 0.9-inch image display device are about 55%, and nearly half of the luminous flux is lost.

The same phenomenon also occurs when a microlens is used as the optical path changing means as shown in the single-plate image display apparatuses of Reference Examples 1, 2 and 3. That is, when the incidence angles of the three primary colors incident on the image display element are different from each other by the two-diagonal dichroic mirror, and the light beam is incident on the pixels displaying the image signals of the primary colors by one microlens at different angles. Since the incident light beam is not a parallel light beam, color mixing and a decrease in efficiency have been observed.

For example, in the example disclosed in Reference Example 1, a light beam of red or blue is obliquely incident on a pixel displaying a green signal, for example, and an image of a color tone different from the original color is displayed, or the pixel is displayed. There was a problem that the light beam did not enter the opening effectively, and the efficiency was low.

As described above, in order to form an image display apparatus capable of displaying images with high projection efficiency and high uniformity of brightness, the functions of an integrator, a polarization conversion element, and a microlens must be effectively utilized.

Among them, the integrator is an indispensable optical element to ensure the uniformity of the brightness of the image and to perform the polarization conversion, but it is necessary to arrange the lenses in two dimensions and to combine two fly-eye lenses. It was said and caused cost up. In other words, the manufacture of molds for replicating the integrator, the base material, and the like are expensive, and they occupy most of the cost of the optical system together with the projection lens.

In addition, in order to realize the function, a specific distance is required, and it is impossible to construct a compact optical system. That is, in the conventional integrator, each lens constituting the first fly's eye lens must focus the incident light flux on each lens of the corresponding second fly's eye lens. At the same time, each lens of the second fly's eye lens must form an image of each lens of the first fly's eye lens on the image display element. The magnification at that time is determined by 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, L2 / L1. Is determined. On the other hand, in order to increase the square conversion efficiency, the first fly's eye lens may be made small and disposed closely within the almost circular output light beam from the reflector, but as a result, the magnification must be increased in addition to the cost up, and L2 becomes large. It could not be compact. Moreover, the integrator could not be comprised by one fly-eye lens.

As described in detail above, the present invention provides a diffractive optical element and an image display apparatus using the same for achieving high light utilization efficiency while maintaining high uniformity of image brightness.

Moreover, the above subject was a problem which arises because the optical behavior uses the lens described so-called geometric optics. The present invention solves the above-mentioned problems by diffractive optical elements based on wave optics, which are not limited by such geometric optics. However, many examples of the use of diffractive optical elements in image display apparatuses have been disclosed. However, these are completely distinct from the technical idea of the diffraction optical element of the present invention and the image display apparatus using the same.

For example, in Japanese Patent Laid-Open No. 6-222361 and Japanese Patent Laid-Open No. 9-73014 (hereinafter, Conventional Example 1), white backlight light is condensed for each color component by hologram, A method of improving light utilization efficiency is disclosed. For example, Japanese Patent Application Laid-open No. Hei 8-220656 (hereinafter, Conventional Example 2) shows an example in which a hologram element is provided on the output side of the liquid crystal panel so that the main rays of the output light flux of the liquid crystal panel are parallel to the optical axis. have.

However, the hologram disclosed in the prior art example 1 is divided into micro-regions, and each micro-region has a light concentrating property, but this is simply a function of condensing a luminous flux of desired light onto a corresponding pixel, that is, a micro lens array having wavelength selectivity. Function to improve the projection efficiency (light utilization efficiency) while maintaining the uniformity of the brightness of the illumination light (that is, the uniformity of the brightness of the projection image), which is only a function of the diffraction optical element of the present invention. Does not have any, and the technical idea is completely separate from the diffraction optical element of the present invention.

Further, the hologram in the conventional example 2 is arranged on the output side (projection lens side) of the liquid crystal display element, and its function is to project the projection lens by parallelizing the output light flux of the liquid crystal display element output at different angles for each color. To reduce the burden on the specification. Therefore, the hologram in the conventional example 2 completely separates the technical idea from the diffraction optical element of the present invention, which makes the uniformity of illumination light incident on the liquid crystal panel high.

In the exposure apparatus used in the field of semiconductor manufacturing, for example, as disclosed in Japanese Patent Application Laid-Open No. 10-70070 (hereinafter, referred to as Example 3), the output light flux from the light source is applied to the diffraction optical element. The separation method is disclosed. In the conventional example 3, the output light beam after the separation is again incident on the optical integrator, superimposed on the object to be illuminated by the lens system, and is merely to separate the output light beam from the light source. In other words, in the projection optical system using the five-pole illumination, only the polarization of the illumination light is used to improve the projection resolution in consideration of the directionality of the circuit pattern. A secondary light source is formed, and the secondary light source image is secured by superimposing on a lighting object with a capacitor lens.

In addition, Japanese Patent Laid-Open No. 63-267900 (hereinafter, Conventional Example 4) discloses an example in which light incident on a hologram head overlaps on a photosensitive material. However, in the conventional example 4, when two-beam interference exposure is performed, it is aimed at realizing precise positioning while changing the angle at which the beams cross each other, and improving the uniformity of illuminance by superimposing the beams. Nothing is disclosed. In addition, two types of openings are provided for the light incident on the hologram head, and an interference height thereof is obtained. The light incident on the entire surface of the diffraction optical element is superposed as in the present invention. It is not.

As described above, in the conventional examples 1 and 2 in which the diffraction optical element is applied to an image display device, a hologram element which simply changes the angle of the output light flux of the hologram or liquid crystal display element having wavelength selectivity and light condensation is disclosed. It is nothing but being. Further, in the conventional examples 3 and 4 in which incident light is separated by a diffractive optical element, separation is merely a method of improving the projection resolution or improving the alignment. As described above, the technical idea that the diffraction optical element, which is a feature of the present invention, as an integrator is used to uniformize the illuminance of the image display element is novel.

Next, first, a conventional hologram element will be described.

In recent years, the development of the hologram element which reproduces the wave front of the light beam which forms an interference height by interference | interfering the bi-beams which are interfering, and records the interference height in heavy chromic acid gelatin, a photopolymer, etc. has become active.

Examples of applications of hologram elements include interference measurement, holographic optical elements, optical information processing such as pattern recognition, holographic displays, and the like, as described in References, Kuboda Satohizer, Introduction to Holography. have.

When the hologram element is applied to the field of image display, not only a three-dimensional image is displayed but also various applications are conceivable.

Hereinafter, the example used for (1) optical switch and (2) direct view type liquid crystal panel is demonstrated.

First, the optical switch will be described. For example, Japanese Patent Application Laid-Open No. 5-173196 of Conventional Example 1 illuminates an interference height on a mixture of a polymer material cured by a wavelength of a light beam forming an interference height and a liquid crystal that is not cured at the wavelength of the light beam, so-called mineral oil. Optical switch which controls the diffraction / straightening of the incident light beam by forming the area | region which consists of a polymeric material hardened by gas phase separation, and the area | region which consists of an uncured liquid crystal, and controls the said uncured liquid crystal by an applied voltage. Is disclosed.

Many of the same examples have been disclosed so far, and for example, in Upright Physics Letters, Vol. 64, No. 9, pages 1074 to 1076, 1994 (hereinafter referred to as Conventional Example 2), the diffraction efficiency can be controlled. It is disclosed as a hologram element.

In this example, the two-beam interference height of the wavelength is illuminated on a mixture of a polymer material that is cured at a specific wavelength and a liquid crystal material that is not cured at this particular wavelength as in the conventional example 1, and the light intensity of the interference height is It is produced by forming a polymer material in a thin portion and a region containing a large amount of the liquid crystal material in a portion where the light intensity of the interference height is weak.

Moreover, although it is not switchable, it is a hologram element formed using optical-organic phase separation by two-beam interference exposure, Unexamined-Japanese-Patent No. 8-162647 (henceforth a prior art example 3), Unexamined-Japanese-Patent No. 9-324259. A large number of examples are disclosed starting from Japanese Patent Application Laid-Open No. 8-142533.

The hologram element fabricated using such a superorganic phase separation phenomenon, as well as two-beam interference exposure, is disclosed, for example, in the liquid crystal discussion '97 Preview pages 86 to 87 (hereinafter referred to as conventional example 5), After mixing the mixture of the ultraviolet curable resin and the liquid crystal material in an appropriate ratio, and injecting the mixture into a cell composed of a glass substrate on which a conductive transparent electrode was formed, irradiated with ultraviolet rays through a grating pattern photomask May be produced.

Although each of the above examples uses mineral organic phase separation to form regions having different refractive indices, this technique is described, for example, in Job Journal, No. 63, pages 14 to 17, December 1995 (hereinafter, referred to as a conventional example). As disclosed in 6), it is a known technique that is also used to produce a micro cell structure for widening the viewing angle of a liquid crystal panel.

In this example, a mixture of the photocurable resin and the liquid crystal is illuminated with lattice light (wavelength is the wavelength for curing the photocurable resin), and a photoorganic phase separation phenomenon forms a micro cell structure surrounding each pixel. have. As a result, the liquid crystal molecules in the liquid crystal region are aligned in the axisymmetric phase stabilized in the photocuring reaction by the self-orientation force, thereby realizing a wide viewing angle and high contrast.

Next, the example applied to the backlight unit of the direct-view type liquid crystal panel 19 is demonstrated, referring FIG. Although the liquid crystal panel of the direct view type is divided into a transmissive type and a reflective type, the transmissive type will be described as an example. For example, as disclosed in Japanese Patent Application Laid-Open No. 9-178949 (hereinafter referred to as Conventional Example 7), the image display device of FIG. 1 is constructed from a cold cathode tube 23 (hereinafter referred to as CCFT) 23 which is a light source. Light is incident on the end face of the light guide 21 and is outputted to the transmissive liquid crystal panel 19 by the hologram element 30 and the reflection mirror 23 formed on the rear surface side of the light guide 21. The hologram element 30 is a reflection hologram.

According to the above configuration, the number of parts can be reduced, the weight is reduced, and the cost can be reduced, and the uniformity and efficiency of brightness are high, and the backlight unit can be used as a directivity. This function is realized by using the hologram element 30 as an aggregate of micro holograms. That is, the mosaic micro hologram is manufactured to show the maximum diffraction efficiency for different incident wavelengths and incident angles.

In the same configuration, for example, as disclosed in Japanese Patent Application Laid-Open No. 9-127894 (hereinafter referred to as Conventional Example 8), the area density of the reflective hologram is increased as the distance from the light source increases. By doing so, an example in which the uniformity of brightness is further realized is disclosed.

In addition, for example, Procedures of International Display Shank `97, pages 411 to 414 (hereinafter, referred to as conventional example 9) or Japanese Patent Application Laid-open No. 9-138396 (hereinafter, referred to as conventional example 10). And a reflection image of the reflection type liquid crystal panel, the incident light beam is selectively reflected (diffraction) substantially in a direction perpendicular to the liquid crystal substrate or into a specific solid angle so that the viewing angle is narrow and bright. Application of displaying is conceivable. This hologram element is a so-called reflective volume hologram.

In addition, in Example 7-10, the general photopolymer is used as a material, and it is a hologram element which always reflects the above-mentioned.

Next, the image display apparatus will be described.

In recent years, since it is difficult to enlarge the size of a conventional direct-view television, the development of the projection type image display apparatus which enlarges and projects the output image of the image display means which modulates the illumination light beam from a high-brightness lamp is progressing (for example, Opras, August 1993, pages 58-101).

Fig. 67 shows the structure of a conventional general projection type image display apparatus, and shows an example of the structure using a liquid crystal panel as the image display means. The output light 3 from the lamp 2 is reflected by the reflector 4, the output light beam 5 is collected and propagated by a condensing optical system (not shown), and the dichroic mirror 12 for color separation is carried out. , 13) to separate the three primary colors of red, green, and blue and enter the liquid crystal panels 16 to 18 through the total reflection mirror 14 and the condenser lens 15. The output light modulated by the liquid crystal panels 16 to 18 is synthesized by a dichroic prism (not shown) or dichroic mirrors 19 and 20 and a total reflection mirror 14 for color synthesis. (9) is magnified and projected on a screen (not shown).

The liquid crystal panels 16 to 18 are mainly classified into a transmissive type and a reflective type, but neither of them forms an image by modulating specific linearly polarized light incident through a polarizing plate or a polarizing beam splitter (hereinafter referred to as PBS) with a liquid crystal material. Display.

In general, the liquid crystal panels 16-18 are switching elements for driving each pixel, and an active matrix method in which thin film transistors (hereinafter referred to as TFTs) are disposed in each pixel is mainly used, and TFTs are formed of polycrystalline polysilicon. Is common.

As the lamp 2, a lamp having high luminous efficiency, a small volume of light emitting material and high color rendering property is obtained, and a metal halide lamp, xenon lamp, ultrahigh pressure mercury lamp, and the like are used.

As the reflector 4, it is easy to effectively utilize the light beam 5 after reflection, and thus, a spectacle mirror, an ellipsoid mirror, a spherical mirror, or the like is used, and the light emitter is often disposed at the focal point or the first focal point or center of the reflector. The current mainstream uses a mirror mirror, and installs a lamp emitter near its focal point to obtain a substantially parallel luminous flux.

In recent projection image display devices, when the full-back signal is displayed,

(1) Make the brightness of the center of the projection image and the brightness of the periphery uniform.

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

The main problem of development is the introduction of the integrator in (1), the combination of the high brightness lamp with the integrator and the small light emitter in (2), and the solution by combining the polarization conversion elements. It is being tried.

First, the integrator will be described. An integrator is a combination of two types of fly-eye lenses composed of two-dimensionally arranged microlenses, as disclosed in, for example, Japanese Patent Application Laid-Open No. 3-111806 and Japanese Patent Application Laid-Open No. 5-346557. It is configured by. 7 shows a specific configuration example of the integrator. The image of the luminous body of the lamp 2 is reflected by the reflector 4 and the first fly's eye lens 49 to form an angle of the second fly's eye lens 50 corresponding to each lens of the first fly's eye lens 49. The image is formed on the lens. Each lens of the second fly's eye lens 50 is configured to form an image of the first fly's eye lens 49 on the image display means 7.

According to the above configuration, an image in which each lens of the second fly's-eye lens 50 forms an image on the image display means 7 generates output light having a large luminance distribution output from the reflector 4. Each lens of 49) is finely divided, and the result is that they are polymerized on the image display means 7. By this principle, it is possible to increase the brightness of the peripheral portion with respect to the image center portion in the projected image to 70% or more.

In addition, by introducing an integrator, the projection efficiency can also be improved. Generally, the light beam 5 reflected by the reflector 4 is almost circular, but the image display means 7 is a rectangle of 4: 3, for example. Therefore, when illuminating the image display means 7 circularly, only the rectangular area ratio inscribed to the circle was effectively utilized. This is called rectangular conversion efficiency, and when the image display means 7 which has a 4: 3 rectangular shape as an outline is used, rectangular conversion efficiency was about 61%. However, by arranging the aperture shape of the lens used for the first fly's eye lens 49 of the integrator as 4: 3, as shown in Fig. 2 of Japanese Patent Laid-Open No. 5-346557, It is possible to improve to 80%.

Next, the polarization conversion element will be described. In the projection type image display apparatus using the polarization display means such as the liquid crystal panel described above, there is a drawback that only the polarization component in the specific direction can be effectively utilized among the output light of the lamp, and the projection efficiency is low. There existed a problem that a light source must be used. The polarization conversion element is developed to solve such a problem, and the polarization component absorbed from the polarizing plate or the polarization component not incident on the liquid crystal panel in the PBS can be effectively used as a polarization component having a polarization plane which is substantially orthogonal to the polarization component. To convert.

Examples of polarization conversion devices include Japanese Patent Application Laid-Open No. 5-107505, Japanese Patent Application Laid-Open No. 6-20294, Japanese Patent Application Laid-Open No. 7-294906, Japanese Patent Application Laid-Open No. 8-234205, and Japanese Patent Publication Although many publications, such as Japanese Patent Application Laid-Open No. 9-105936, are disclosed, it basically consists of a combination of a polarization separating element and a polarization plane rotating element.

8 shows the configuration of a general polarization conversion element 58. Polarized light (randomly polarized light beam) 62 is orthogonal to each other by the polarization splitting element 60, that is, P polarized light (not polarized by the polarization splitting element and is parallel to the ground to be transmitted) Light beam having a polarization direction) 63 and S polarized light (reflected by polarized light separating means and having a polarization direction perpendicular to the ground) 64, and reflecting only the S polarized light 64 In the principle of reflecting by means 60` (generally the same film as polarization separating means 60) and converting it into P-polarized light 63` by the polarization plane rotating element 61 It is based.

In recent years, it is often composed of a combination with the lens array 66, and the contents of the above five publications can also be used by combining with the lens array 66, but slightly configured by the installation position of the polarization splitting element. This is different.

In one method, the width of the light beam incident on the polarization conversion element 58 is about 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 FIG. 9). In this case, the lens array 66 is a fly-eye lens constituting the integrator, so that the uniformity of the brightness of the projected image can be secured at the same time as described above. That is, a configuration in which the lens array is used as the second fly's eye lens of the integrator is considered.

On the other hand, as disclosed in Japanese Patent Application Laid-Open No. 6-202094 and Japanese Patent Application Laid-Open No. 8-234205, a polarization splitting element is provided on the lamp side of the first fly's eye lens, and the By changing the exit angle several times in accordance with the polarization component, a method of changing the position formed on the second fly's eye lens for each polarization component and rotating only the polarization component of one polarization component is also devised. As an application of this system, it is also conceivable to provide a polarization splitting element between the first fly's eye lens and the second fly's eye lens.

In a conventional polarization converting element, a dielectric multilayer film formed by stacking a plurality of dielectric layers is almost used as a polarization separating element. A hologram element having polarization selectivity as a polarization splitting element is known in the art, but an example in which the hologram element is combined with an integrator to form a polarization converting element and applied to an illumination optical system of a projection image display device is not disclosed.

In the hologram device having polarization selectivity disclosed in Japanese Patent Application Laid-open No. Hei 8-234143 and U.S. Patent No. 5161039, a polarization selectivity is obtained by using a liquid crystalline polymer or a polysilane polymer material having a nonlinear light absorption effect. Each polarized light has a function as a so-called volume hologram.

Moreover, in the use of a projector, it is important to improve the light utilization efficiency of the liquid crystal light valve because there is a high demand for a bright projection image that can be recognized without darkening the room. As an optical system for increasing the uniformity of the illumination area, Japanese Patent Laid-Open No. 3-11180, Japanese Patent Laid-Open No. 5-346557, and the like disclose an integrator optical system using two lens plates.

In principle, this is the same as that used in an exposure machine. The parallel light beam from the light source is divided by a plurality of rectangular lenses, and the image of each rectangular lens is a relay lens corresponding to each rectangular lens in a one-to-one manner. It is to overlap the image.

In addition, Japanese Patent Laid-Open No. 6-202094 proposes an illumination optical system in which the integrator illumination method is combined with the polarization conversion method. This schematic is shown in FIG. The light emitted from the light source 1101 enters the polarization splitting element using liquid crystal, and is separated into a P wave 1106 and an S wave 1107. These lights are imaged at different positions of the phase plate 1105 arranged behind the second lens 1104 by the first lens group 1103 and the second lens group 1104 constituting the integrator. . In the phase plate 1105, a half wave plate is periodically formed in an area of almost half of one lens forming the second lens group.

For this reason, for example, the P wave 1106 imaged at the position of this half wave plate, and it rotates by 90 degrees, turns out as S wave. The S wave 1107 is formed in a region where the half-wave plate is not formed and is transmitted as it is. As a result, the light waves after exiting the phase plate 1105 generally have the same polarization direction.

Japanese Patent Laid-Open No. 7-294906 reports a polarization conversion element in which a lens plate and a prism are combined. This outline is shown in FIG. The light waves incident on the lens plate 1201 in which the lenses on the array are formed are bundled by the light beam and enter the prism 1202. Here, the S wave 1204 passes as it is, and the P wave 1205 is reflected by the prism and enters a nearby prism, and is reflected again to change the 90 ° angle.

Then, the polarization direction is rotated 90 degrees through the 1/2 wave plate placed in the optical path and emitted as S wave. As described above, the light waves emitted by the combination of the lens plate 1201 and the prism 1202 become light beams having the same polarization direction.

Here, the image display principle of the liquid crystal element will be described with reference to FIG. For example, light emitted from a light source 901 such as a fluorescent lamp or a metal halide lamp is composed of a P wave 902 having a polarization direction parallel to the ground and an S wave having a polarization direction perpendicular to the ground. This light beam is incident on the polarizer 904, and a specific polarization component is absorbed and the remaining component is transmitted. In the polarizer 904, a component of S wave is absorbed and P wave is transmitted. Light transmitted through the polarizer 904 is incident on the liquid crystal element 905.

Here, as a liquid crystal element 905, a twist nematic liquid crystal in which the directions of liquid crystal molecules are twisted by 90 degrees at the entrance and exit surfaces will be described as an example. A patterned transparent electrode is formed in the liquid crystal element 905 and an electric field can be applied to each pixel. In the pixel (ON) to which an electric field capable of completely switching the liquid crystal is applied, the liquid crystal molecules are distorted and the liquid crystal molecules are isotropically standing with respect to the incident surface (homeotropic). It is. For this reason, the P wave incident on this pixel passes through the liquid crystal element while maintaining its polarization state without being modulated.

Next, in the pixel OFF to which the electric field is not applied, the liquid crystal molecules are in a state where the angle of the 90 ° liquid crystal molecules is distorted in the thickness direction from the incident surface to the exit surface. For this reason, the P wave component incident on this pixel rotates the polarization plane by 90 degrees by the twisted nematic effect resulting from the distortion of the liquid crystal between the entrance face and the exit face. Therefore, after passing through the OFF pixel, the first light is emitted as an S wave.

After passing through the liquid crystal element, the polarization direction of the light varies depending on the presence or absence of the 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 to be inclined by 90 ° with respect to the first polarizer 904 through the polarization component. As a result, the polarizers 904 and 906 are arranged in cross nicol. For this reason, the P wave in the light passing through the liquid crystal element 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 device is modulated according to the electric field applied to the pixel, and as a result, the intensity of light passing through the polarizer 906 is different. Since the observer 907 has a different amount of light passing through the polarizer 906, an image as a pattern of light and dark corresponding to each pixel is recognized.

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

Next, the optical information processing apparatus will be described.

An optical information processing apparatus for recording or reading information stored in an optical storage medium such as an optical disk or a magneto-optical disk is mainly a semiconductor laser as a light source, a lens for converging light emitted from the semiconductor laser onto the optical storage medium, And a hologram element as a diffractive optical element for guiding the laser light reflected on the optical storage medium to the light receiving element.

First, the light emitted from the semiconductor laser passes through the hologram element and is focused on the surface of the optical disk as the optical storage medium by the imaging lens. The light reflected and spread from the surface of the optical disk to the intensity according to the recording information is converged by the lens again, partly returned to the semiconductor laser, and partly divided into two directions by, for example, a hologram element divided into two areas. The image is divided into light-receiving elements divided into several areas, and focus shift, tracking shift, and detection of an information signal are performed using a method such as the knife edge method.

As described above, the emitted light from the laser passes through the hologram element serving as the diffractive optical element twice, in the forward and return directions. If the light is strongly diffracted after passing through the hologram element in the path, the amount of light focused on the surface of the optical disk may be reduced, and sufficient light intensity may not be obtained on the disk, which may interfere with accurate detection of signal information. . For this reason, the hologram element generally requires a function that differs in diffraction efficiency between the return path and the return path.

Some semiconductor lasers as light sources have polarization characteristics, and selectivity of diffraction efficiency in the polarization direction is often used. Specifically, the polarization direction of the light emitted from the semiconductor laser is transmitted as it is without diffraction, and then a phase plate such as a quarter wave plate is disposed in the optical path with the disk, and the disk is disposed by the disk. When the reflection is passed through the hologram again, the polarization direction is set to rotate by 90 ° relative to the initial stage. At this time, the hologram element produces a diffraction function, and the light passing through the hologram element is guided to a light receiving element that detects an information signal or the like.

The hologram having such polarization selectivity is produced using an optical matrix having refractive index anisotropy. For example, a mask is formed on a predetermined area of the surface of an optical medium having refractive index anisotropy, such as lithium niobate, by photolithography, holographic exposure, or the like, and ion is used on the exposed area of the surface by using benzoic acid or the like. Exchange it. Then, the refractive index distribution does not occur with respect to a specific polarization direction, and can be handled as the same object.

However, for the light in the polarization direction orthogonal to the preceding polarization direction, a refractive index distribution formed by the mask is produced, and a diffraction phenomenon corresponding to this pattern is produced. An optical information processing apparatus is constructed using a hologram element having such characteristics.

The whole hologram element disclosed in the above-described conventional examples 1 to 6 is an optically almost isotropic photocurable polymer material which does not always have refractive index anisotropy, and a liquid crystal material which does not cure at a wavelength for curing the photocurable polymer material. It is formed by a mixture with the following (hereinafter referred to as non-polymerizable liquid crystal), and they are formed by forming fine regions. Therefore, for example, in the conventional example 1, even if a voltage is applied to a region of only the non-polymerizable liquid crystal to diffract, there is a drawback that, for example, the obliquely incident light beam acts as a hologram. This form is explained using FIG. 2 and FIG.

The conventional hologram device has a region 1 made of a photocurable polymer material optically nearly isotropic (refractive use is n1) and a region 2 made of a non-polymerizable liquid crystal as shown in Fig. 2A ( The liquid crystal molecules have the refractive index anisotropy shown and are formed by the refractive indices with respect to the normal light and the abnormal light, respectively, no and ne.

N1 and no select substantially the same material here. When a voltage is applied to the transparent conductive electrode 1 (hereinafter referred to as ITO) and the liquid crystal molecules in the region 2 are switched, the liquid crystal molecules are arranged almost perpendicular to the glass substrate 2.

In this case, with respect to the light beam 3 incident perpendicularly, the refractive index is almost optically isotropic (regions 1 and 2 together) with respect to P-polarized light (polarization component parallel to the ground) and S-polarized light (polarization component perpendicular to the ground). no), the light beam 3 goes straight without diffraction.

When no voltage is applied to the region 2, as shown in FIG. 2B, liquid crystal molecules are arranged almost parallel to the glass substrate 2, and refractive index anisotropy occurs in the region 2.

As a result, for example, for the P-polarized light, the entire region acts almost as an isotropic parent of the refractive index no, whereas the P-polarized light acts as a hologram element that alternately changes to ne and n1. Therefore, in the incident light beam 3, the P-polarized light 4 is diffracted and the S-polarized light 5 is straight ahead.

However, as shown in Fig. 3A, the refractive index anisotropy is also applied in the region 2 even in a mode in which the liquid crystal molecules are vertically arranged by applying a voltage to the incident light beam 3` and the incident light beam is straight. This happens. In other words, the normal light (in this case, S-polarized light) acts as an isotropic parent with a refractive index of no. This is because the incident light is diffracted. Therefore, for example, when trying to use it as an optical switch, there is a drawback that complete control cannot be performed except for vertical incidence.

In fact, even if the region 1 is formed using a photocurable polymer material which does not have refractive index anisotropy in nature, it forms refractive index anisotropy even though it is formed between the glass of a narrow gap although it is slightly caused by stress or the like. However, the difference is small and essentially the above phenomenon occurs.

The slight refractive index anisotropy may be a problem. For example, in the case of the conventional example 6, when the black is displayed, a portion of the lattice becomes a discontinuous region, and is particularly noticeable when displaying a high contrast image, and loses uniformity. There was a flaw.

Various problems described in detail above are problems that always occur in a system in which phase separation is expressed by using a mixture of an optically almost isotropic photocurable polymer material and a liquid crystal material as a material.

On the other hand, an example of producing a retardation film of a liquid crystal polymer composite using a mixture of an ultraviolet curable liquid crystal and several kinds of non-polymerizable liquid crystals, which has recently been particularly noticed as a photocurable liquid crystal, has been reported (for example, the `97 liquid crystal discussion Preview page 168-169, 1997). However, in the above example, the UV light is simply irradiated to the entire surface or uniformly, and the entire surface is evenly cured, and the interference height is formed by the separation of the photoorganic phase by two-beam interference exposure, and as will be described later. No mention is made of the effect that diffraction does not occur even with oblique incident light expected by the configuration.

For example, Japanese Patent Application Laid-Open No. 9-281330 and Japanese Patent Application Laid-open No. 9-288206 disclose that a photocurable liquid crystal is injected into a cell in which a stripe-shaped ITO is formed and a voltage is applied to partially align the orientation of liquid crystal molecules. By photocuring in a different state, the diffraction element is formed.

However, the above examples are formed using an essentially homogeneous liquid crystal material, and nothing is disclosed regarding the use of a mixture with a nonpolymerizable liquid crystal, and the refractive index anisotropy between the different regions is the same, but switching is not possible. And essentially different from the present invention.

In the example applied to the direct-view liquid crystal panel disclosed in the prior art examples 7 to 10, the hologram element always realizes the above-described function, and the example in which the function of the hologram element is changed as necessary is disclosed at all. It is not.

In addition, in the conventional image display apparatus, in the case of forming the polarization separation means using the dielectric multilayer film, there is a drawback in that it takes time to manufacture and high cost since multiple thin film dielectric layers are laminated.

In addition, the polarization splitting device disclosed in Japanese Patent Application Laid-Open No. 7-294906 and Japanese Patent Application Laid-open No. 9-105936 formed by opposing a plurality of prisms and forming a dielectric multilayer film on a bonding surface has difficulty in manufacturing and cost. There was a problem such as high, heat resistance of the adhesive.

In Japanese Patent Laid-Open Nos. 5-107505 and Japanese Patent Laid-Open No. 8-234205, thick parallel plates or right angle prisms are used, and a compact structure is difficult. Moreover, in Unexamined-Japanese-Patent No. 6-20294, preparation of the sawtooth shape was difficult. As described above, the polarization splitting device using the dielectric multilayer film has the disadvantage of high cost and difficulty in fabrication.

In addition, the polarization splitting device using the hologram element having polarization selectivity disclosed in Japanese Patent Application Laid-open No. Hei 8-234143 and U.S. Patent No. 5161039 is an illumination optical system in a projection image display device as described above. No application is disclosed as a combined polarization conversion element. On the other hand, even when a conventional hologram element is assembled to a polarization converting element as a polarization splitting element and applied to a projection type image display device, it is difficult to realize high efficiency for the following reasons.

For example, consider a case where a polarization splitting element is provided in front of the first fly's eye lens of the integrator. Incident on the polarization splitting device is usually a substantially parallel luminous flux. These beams are naturally unpolarized light. In this case, the difference between the exit angles of the two polarized light beams outputted from the polarized light separation element after polarization separation and mutually perpendicular to each other is preferably only a few times. This is because two images of the luminous body of the lamp are imaged on each microlens of the second fly's eye lens corresponding to each microlens of the first fly's eye lens. If the angle difference is too large, the diameter of each lens of the second fly's eye lens must be increased.

That is, as a polarization splitting device, after substantially parallel light beams are separated into different polarization components, each must be output at several angle differences. This means that the difference in incidence angles between the reference light and the object light when manufacturing the hologram element must be reduced to only a few. In general, however, in order to make the efficiency of the volume hologram high enough to withstand the use, the difference between the incident angle of the reference light and the object light is required at least 20 times, and the efficiency of the volume hologram becomes low at the angle difference smaller than that. . Therefore, the polarization conversion element of the first type could not be constructed by using the conventional hologram element as the polarization separation element.

As the diffraction element, for example, as disclosed in Japanese Patent Application Laid-Open No. 5-173196, an example using a normal nematic liquid crystal, or Japanese Journal of Abide Physics, Vol. 36, 1997, 589- Examples of using UV-curable liquid crystals as disclosed on page 590 or polymer dispersed liquid crystals as disclosed in Chemical Materials, vol. 5, pp. 1533 to 1538, 1993, are also known. It merely discloses having a polarization separation function, and nothing is disclosed about the application as a polarization conversion element.

As described above, when a polarization converting element combined with an integrator is formed by using a polarization separating element formed of a conventional dielectric multilayer film, and applied to a projection type image display device, (1) cost is high, and (2) fabrication is difficult. (3) There were problems such as difficulty in compact construction.

In addition, in the hologram element, (1) efficiency is lowered unless the difference between the incident angle and the output angle is increased. (2) It was difficult to use as a polarization separation element of the projection type image display apparatus in combination with the integrator.

In the conventional diffraction element,

(1) It merely discloses having a polarization separation function,

(2) Nothing is disclosed about the combination with the integrator and cannot be applied to the projection image display apparatus.

In addition, in the polarization splitting device using the liquid crystal, the liquid crystal is sandwiched between the prism substrate having the sawtooth groove and the glass substrate. In order to show refractive index anisotropy, a liquid crystal differs in refractive index difference by polarization directions, such as normal light and anomaly light.

The light waves incident on the foregoing polarization splitting element generate a phase distribution corresponding to the sawtooth shape and function as a phase diffraction grating. Moreover, the refractive index difference at the time of passing through a liquid crystal layer by a polarization direction differs. For this reason, since the phase distribution differs depending on the polarization direction of the incident light source, the direction diffracted by the normal light and the abnormal light, and eventually the P wave and the S wave, is emitted differently.

In order to separate the P wave and the S wave in the shape of the second lens array, a diffraction angle of a separable degree is required. For this reason, it is necessary to reduce the tooth pitch of the polarization splitting element to about several tens of micrometers. At this time, it is necessary to design the inclination of the sawtooth uniformly and strictly. This is because the inclination of the sawtooth is equivalent to the phrase angle of the diffraction element, and therefore the shape and uniformity affect the efficiency of the diffraction wave. As a result, when the sawtooth groove is out of alignment with the design, the problem arises that the diffraction wave is dispersed and the degree of separation by the polarization splitting element is lowered.

Increasing the width of the gap between the sawtooth grooves can increase the pitch of the sawtooth and facilitate the processing. In this case, when the separation angle is maintained at the same level as in the original case, it is necessary to thicken the cell gap of the liquid crystal. However, it is difficult to uniformly align the liquid crystal in a thick cell gap, causing a phenomenon such as cloudiness, and reducing the transmittance of the polarization splitting device.

In a polarization splitting device using a prism, the light beam is bundled by a lens plate and is incident on the prism array every other row. Since the prism has the function of a polarizing beam splitter, for example, it transmits S waves and reflects P waves at right angles, and is reflected at right angles from adjacent prisms so that the propagation direction of light becomes the same as the preceding S waves. Subsequently, the 90 ° polarization direction is rotated by the 1/2 wave plate placed in the optical path and is emitted as a P wave.

Since the above operation is performed for each prism, the light wave incident on the lens plate can obtain the light beam having the same polarization direction without significantly changing the width of the light beam. The prism is composed of a cube shape filled with a liquid or solid to obtain refractive index matching with the dielectric multilayer. In order to increase the degree of polarization separation, multiple layers of dielectric multilayer film need to be formed, and manufacturing cost becomes expensive. In addition, the separator is arranged at 45 degrees to bend the propagation direction of light by 90 degrees. For this reason, the size of the separation element in the thickness direction is fixed according to the size of the separation membrane constituting one prism, and a problem arises that the element cannot be made thin and small.

SUMMARY OF THE INVENTION The present invention solves the problems of the prior art, and provides a light utilization efficiency polarization lighting apparatus using a diffraction optical element excellent in polarization selector and having high diffraction efficiency as a polarization separation device, and the polarization lighting apparatus and projection optics It is an object of the present invention to realize a projection display device capable of forming a bright projection image by combining crabs.

In addition, although the use of portable displays for the purpose of viewing video and image information on monitors for car navigation and personal use is increasing, they are mobile phones, including head-up displays and mobile phones called mobile tools. It is positioned as a low power consumption type display for information terminals. Common conditions required for such a display include small size, light weight, thin shape, and low power consumption. In the head-up display, it is also necessary to switch between the display screen and the outside world, and it is preferable that the screen is transparent, that is, a see-through screen.

At present, a display using a liquid crystal element can be considered as a display suitable for the above requirements. The liquid crystal display has a smaller depth area and a thinner thickness than a conventional display such as a CRT. In addition, high definition has been progressed by the reduction in pixel size, the increase in capacity, the introduction of TFT elements, and the like, and the picture quality has been gradually improved.

Generally, however, the image display principle of a display using a liquid crystal element modulates the polarization direction of incident light by the magnitude of an electric field applied to the liquid crystal element. By combining the polarizers arranged in cross nicol before and after the liquid crystal element, image information such as light and dark is displayed by using the difference in the transmittance of the polarizer due to the polarization state of the incident light.

In this manner, the light transmittance is not so high because the polarizer is an absorption type. In addition, since the polarizer is formed by combining with cross nicol, in the state only of this polarizer combination, there is little light transmittance and it is a black state. Therefore, in parallel with image display, it is difficult to obtain external information through the liquid crystal panel, and there is a problem that it cannot be used as a see-through type head-up display.

Moreover, since a polarizer is a structure which transmits only a specific polarization component by absorption of light, the light absorbed by a polarizer is converted into heat inside. When the amount of incident light increases, the influence of heat generation inside the polarizer cannot be ignored, and the problem of deterioration of the function of the light modulation function of the polarizer and element deterioration occurs.

Since a liquid crystal display does not exist in a self-luminous type device such as a CRT, a dedicated light source is required for image display. Of the power consumption of the liquid crystal display, the ratio of power used for the light source accounts for about half of the total, which is an obstacle to lower power consumption. For this reason, the method of displaying an image, without using the exclusive illumination light source is examined. As a method for this, there is a reflection type image display apparatus in which external light such as natural light or indoor illumination light is used as a light source, and a liquid crystal element and a reflecting plate are combined. According to this configuration, since a dedicated light source is not required, low power consumption can be achieved.

In the above manner, the display state of the image is changed by the state of external light used as illumination light. For example, viewing of image information becomes difficult when the illumination light in the night room is dark or in a place where the illumination light cannot be used. For this reason, it is desirable to switch between the backlight as an internal light source and the place where the external light is used, environmental conditions, and the like, and to have a low power consumption and convenient viewing of image information.

However, in order to use external light, it is suitable to take a reflection type structure having one polarizer on the front side of the liquid crystal element, and to use an internal light source, a transmissive type structure in which cross polarizers are arranged before and after the liquid crystal element. It is desirable to. In order to satisfy both methods simultaneously, it is conceivable to have a configuration using two polarizers. However, when an absorbing polarizer is used, the transmittance is low, and the brightness of the screen is remarkable in the image display in the reflection type by external light. Deterioration and image quality deteriorate. Therefore, there exists a problem that use of combined use with an internal light source and external light is difficult.

The present invention solves the above-mentioned problems of the prior art, constitutes an image display device by combining a diffraction optical element excellent in polarization selector and high diffraction efficiency with a liquid crystal element, and enables a see-through display and is an internal light source. An object of the present invention is to provide a low power consumption image display device that can be used together with a backlight and external light. In addition, by using the diffractive optical element as a transmission type having modulation of the refractive index distribution, it is aimed at increasing the utilization efficiency of the light and for multi-purpose application as a lighting device for illuminating light simultaneously with image display.

On the other hand, when the signal detection from the optical storage medium is carried out using a hologram element having polarization selectivity produced by ion exchange or the like, the signal detection is greatly influenced by the diffraction efficiency of the hologram element. Specifically, it is reflected by an optical disk or the like, and the polarization direction is changed to be orthogonal to the initial state by the phase plate, and is incident on the hologram element.

At this time, when the diffraction efficiency of the hologram element is low, the intensity of light reaching the light receiving element is weak, so that the noise increases and accurate signal detection becomes difficult. In addition, since the components transmitted without diffraction are irradiated to the semiconductor laser as a light source, instability of laser oscillation occurs due to an increase in the amount of light returned to the semiconductor laser, and problems such as generation of noise in the light source itself are newly generated. Goes.

In order to solve this problem, it is necessary to improve the polarization selectivity and diffraction efficiency of the hologram element. As a form which can be used as a hologram element currently having polarization selectivity, there exists a type of the two-dimensional diffraction optical element. This has a refractive index table corresponding to the rectangular lattice shape and generates a phase difference of 0 and π for each adjacent lattice with respect to the wavelength of incident light. The light passing through this generates diffraction as a result of being stronger in a specific direction corresponding to the spacing of the short lattice.

In the hologram element made of such a short lattice, diffraction waves are generated bilaterally and symmetrically for a shape consisting of two-dimensional binary. For this reason, there is a problem that even the ideal diffraction efficiency focused in the primary direction with the largest diffraction intensity is limited to about 40%. In addition, when the lattice shape deviates from the design value, the intensity ratio diffracted to a higher order other than the primary light intensity, starting with the zeroth order light intensity, increases. Therefore, not only the required primary light intensity is lowered but also the problem that high-rotated light acts as the light returning to the semiconductor laser causes noise to be generated for the laser oscillation as described above.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art and to provide a diffractive optical element used in an optical information processing apparatus excellent in polarization selectivity and high in diffraction efficiency, and a highly reliable manufacturing method thereof.

(Initiation of invention)

This invention is made | formed in order to solve the said subject. A group of inventions for achieving this object is comprised as follows.

Has a plurality of regions with different composition of materials,

The plurality of regions are formed of a photocurable liquid crystal having a refractive index anisotropy and cured at least by a specific wavelength;

By the said wavelength, it forms in the 2nd area | region which consists of non-hardened liquid crystal (henceforth nonpolymerizable liquid crystal),

The refractive index with respect to the normal light and the abnormal light after hardening of the said photocurable liquid crystal is substantially the same as the refractive index with respect to the normal light and the refractive index with respect to the abnormal light of the said nonpolymerizable liquid crystal, respectively.

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

Usually composed of first and second hologram elements in the shape of plates that selectively diffract only the first polarization component,

An angle θ0 formed between the incident light beam and the optical axis incident on the first hologram element,

An angle θ1 at which the incident light beam forms the optical axis of the first output light beam diffracted by the first hologram element,

The angle θ2 of the second light flux diffracted after the first output light beam enters the second hologram element and is output is expressed by the following equation

| θ1-θ2 | 〉 20

| θ0-θ2 | 〈15

Polarization separator, characterized in that to satisfy.

At least a diffractive optical element having a light source and refractive anisotropy and a total reflection mirror disposed adjacent thereto,

The polarization component (P wave or S wave) in one direction of the light emitted from the light source passes through the diffraction optical element and is reflected by the reflecting mirror, and then passes through the diffraction optical element and exits.

When the component (S wave or P wave) orthogonal to the emitted light is emitted by changing the propagation direction by the diffraction action of the diffractive optical element, the diffracted wave from the diffractive optical element and the reflected wave from the total reflection mirror And a predetermined wavefront of the diffractive optical element is formed such that the propagation directions of are substantially the same and the relative emission angles are different.

With a light source,

A liquid crystal element having a liquid crystal layer sandwiched by two opposing transparent insulating substrates having a transparent conductive electrode patterned to form a pixel;

Diffraction optical elements arranged on both sides of the liquid crystal element,

It is configured to include at least,

The light emitted from the light source is incident on one diffractive optical element and diffracted

About 1/2 of the amount of incident light to the diffractive optical element is incident on the liquid crystal element,

Modulated for each pixel of the liquid crystal device,

An image display apparatus according to the modulation degree, wherein image display is performed by an operation in which the propagation direction of light after passing through the other diffractive optical element is different.

The polarization direction of the laser emitting radiation, the optical lens for converging the laser light emitted from the laser onto the optical storage medium, and the polarization direction of the laser light reflected by the optical storage medium in a direction perpendicular to the polarization direction of the light at the time of emission. Diffraction used in an optical information processing apparatus having at least a component comprising a phase plate for rotating, a diffraction optical element disposed in an optical path of the reflected light to generate a predetermined wavefront, and a light receiving element for detecting light diffracted by the diffraction optical element In the optical element, the diffractive optical element is formed by using an optical medium having refractive index anisotropy, and is reflected by the optical memory medium, and has a primary direction with respect to the total light amount of the laser light after passing through the diffractive optical element. Characterized in that a predetermined wavefront is formed so that the ratio of the amount of light diffracted by Diffraction optical element.

A first and second hologram elements on a plate disposed substantially parallel to each other and selectively diffracting a predetermined polarization component that are substantially equal to each other,

A diffracted light beam incident on the first hologram element, diffracted by the first and second hologram elements, and exiting the second hologram element;

The angle formed by the transmitted light beam incident on the first hologram element, transmitted through the first and second hologram elements and exiting the second hologram element is greater than 0 ° and less than 15 °. ,

The angle between the light flux incident on the first hologram element and the light flux incident on each hologram element at the light flux diffracted by the first and second hologram elements and the light flux diffracted by each hologram element are each 20 °. Polarization splitter, characterized in that exceeding.

A liquid crystal element for modulating the polarization direction of incident light in accordance with an applied voltage;

First and second pairs of diffractive optical elements disposed on both sides of the liquid crystal element and selectively diffracting a predetermined polarization component, and transmitting a polarization component orthogonal to the predetermined polarization component and the polarization direction. An image display device comprising:

A hologram element produced by interfering an object light and a reference light, wherein the object light is an almost parallel luminous flux (hereinafter referred to as an object luminous flux), wherein the reference light condenses and propagates a first luminous flux emitted from the light emitting means. A hologram element characterized in that it is a luminous flux (hereinafter referred to as a reference luminous flux) having a wavefront substantially equivalent to the output luminous flux from the means.

At least an image display means and illumination means for illuminating the image display means, wherein the image display means displays an image by modulating and outputs illumination light from the illumination means incident on the image display means, and the illumination The means comprises at least light emitting means, first condensing means for condensing the output light flux of the light emitting means, and first wavefront converting means for converting the wavefront of the output light flux of the first condensing means. And the wavefront converting means is a first hologram element formed by interfering a first luminous flux and a second luminous flux substantially equivalent to a wavefront of the output luminous flux of said first condensing means.

A diffractive optical element comprising a plurality of micro-regions, wherein the output light flux of the micro-regions is a light beam which generally overlaps each other on a plane intersecting at a predetermined angle with a normal direction of the diffractive optical element.

The present invention relates to an image display apparatus for displaying a bright and high quality screen and a hologram element used in the image display apparatus.

The present invention also relates to a polarization splitting element that separates an incident light beam into another polarization component, and a projection type image display device configured by using the same and administering and displaying an image.

In addition, a polarization illumination device that obtains uniform illumination light having the same polarization direction by using a polarization splitting device, and a projection display device that enlarges and displays an image by modulating the polarization light emitted from the polarization illumination device by a light valve. It is about.

In addition, the monitor for image display, the display device for the portable information terminal, the head-up display for vehicle use or personal use, and the image display device used for road traffic sign or information display, and the illumination device for illumination light, etc. It is about.

Further, an optical information processing apparatus including an optical head, an optical pickup, or the like for recording or reading information recorded on an optical storage medium such as an optical disk or a magneto-optical disk using a laser light, and diffraction optics used therein It relates to an element.

1 is a block diagram of a conventional projection image display apparatus.

2 is a configuration diagram of a conventional image display apparatus.

3 is a configuration diagram showing an integrator used in a conventional projection type image display apparatus.

4 is a configuration diagram showing an integrator used in a conventional projection type image display apparatus.

5 is a configuration diagram of the image display device configured in the first embodiment.

Fig. 6 is a diagram showing a method of illuminating a light beam for producing a hologram element for use in an image display apparatus.

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

8 is a diagram showing a method of illuminating a light beam for producing a hologram element used in an image display apparatus.

9 is a principle diagram for generating an incident light beam for manufacturing a hologram element used in an image display apparatus.

Fig. 10 is a principle diagram for generating an incident light beam for manufacturing a hologram element for use in an image display device.

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

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

Fig. 13 is a configuration diagram of the image display device constructed in the first embodiment.

14 is a configuration of another image display device constructed in the first embodiment.

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

16 is a configuration diagram of another image display device constructed in the first embodiment.

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

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

19 is a diagram showing a polarization conversion element used for another image display device in the same manner.

20 is a configuration diagram of the image display device of Embodiment 1. FIG.

21 is a configuration diagram of an optical system for manufacturing a hologram element.

Fig. 22 is a configuration diagram of the image display device of the second embodiment.

23 is a configuration diagram of an image display device of a third embodiment.

24 is a configuration diagram of an image display device of a fourth embodiment.

25 is a configuration diagram of an image display device of a fifth embodiment.

Fig. 26 is a configuration diagram of the image display device constructed in one embodiment.

27 is a plan view of a diffractive optical element.

Fig. 28 is a configuration diagram of another image display device constructed in one embodiment.

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

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

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

32 is a plan view of a diffractive optical element.

33 is an explanatory diagram of a method of manufacturing the hologram element.

34 is an explanatory diagram of another method for manufacturing the hologram element.

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

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

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

38 is a diagram illustrating the configuration of another image display device constructed in one embodiment.

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

40A is a diagram showing the configuration of the hologram element constructed in one embodiment, the arrangement of liquid crystal molecules, and the refractive index of each region.

FIG. 40B is a diagram showing the configuration of the hologram element constructed in one embodiment, the arrangement of liquid crystal molecules, and the refractive index of each region.

FIG. 41 is a diagram showing the function of the hologram element constructed in one embodiment with respect to the obliquely incident light flux and the refractive index of each region. FIG.

FIG. 42A is a diagram showing a configuration of a hologram element constructed in another embodiment, an arrangement of liquid crystal molecules, and a refractive index of each region.

FIG. 42B is a diagram showing the configuration of a hologram element constructed in another embodiment, the arrangement of liquid crystal molecules, and the refractive index of each region.

43 is a configuration diagram of a polarization splitter configured in one embodiment.

FIG. 44 is a plan view showing the alignment state of liquid crystal in one process of polarization splitting element constructed in one embodiment. FIG.

Fig. 45 is a schematic diagram showing the intensity distribution of the alignment state of the liquid crystal and the input interference height in one process of the polarization splitting device constructed in one embodiment.

FIG. 46 is a schematic diagram showing an alignment state of liquid crystals in the polarization splitting device configured in one embodiment. FIG.

Fig. 47 is a view showing the efficiency of the polarization splitting element constructed in a single room.

48 is a cross-sectional view showing an example of an internal configuration of a diffractive optical element.

FIG. 49A shows an example of angle and wavelength dependence of a diffractive optical element.

FIG. 49B is a diagram showing an example of angle and wavelength dependency of the diffractive optical element.

50 is a configuration diagram of an embodiment of a polarization lighting apparatus using a diffractive optical element.

Fig. 51 is a configuration diagram of an embodiment of a polarization lighting apparatus using a diffractive optical element.

52 is a configuration diagram of an embodiment of a polarization lighting apparatus using a diffractive optical element.

53 is a configuration diagram of an embodiment of a polarization lighting apparatus using a diffractive optical element.

54 is a configuration diagram of an embodiment of a polarization lighting apparatus using a diffractive optical element.

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

56 is a configuration diagram of an embodiment of a polarization lighting apparatus using a diffractive optical element.

Fig. 57 is a configuration diagram of the image display device using the hologram element.

Fig. 58A is a block diagram showing one embodiment of the transmissive color display type projection display device.

58B is a configuration diagram showing an embodiment of the transmissive color display type projection display device.

FIG. 59A is a block diagram showing an embodiment of a reflective display device of a color display type. FIG.

Fig. 59 (b) is a block diagram showing an embodiment of the transmissive color display type projection display device.

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

Fig. 61 is a configuration diagram of another embodiment of the image display device using the diffractive optical element.

Fig. 62 is a configuration diagram of an embodiment of a reflection type image display apparatus using the diffractive optical element.

Fig. 63 is a configuration diagram of an embodiment of a reflection type image display apparatus for a backlight combination using a diffraction optical element.

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

Fig. 65 is a configuration diagram of one embodiment as an image display device and an illumination device using diffractive optical elements.

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

67 is a configuration diagram of an embodiment of a compact image display device using the diffractive optical element.

FIG. 68A is a block diagram of an image display apparatus having another configuration using a hologram element.

FIG. 68B is a diagram showing the configuration of an image display device having another configuration using a hologram element.

69 (a) is a block diagram of a hologram element used in the image display device of another embodiment.

69B is a configuration diagram of a hologram element used in the image display device of another embodiment.

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

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

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

Fig. 72 is a view showing the optical system constructed in one embodiment of the method for manufacturing a diffractive optical element.

Fig. 73 is a diagram showing an optical system constructed as one embodiment of the method for manufacturing a diffractive optical element.

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

FIG. 75A shows the structure of a conventional optical switch and the refractive index of each region. FIG.

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

Fig. 76 (a) is a diagram showing the function of a conventional optical switch and the refractive index of each region with respect to oblique incident light.

FIG. 76B is a configuration diagram of an index ellipsoid that exhibits refractive index anisotropy of an obliquely incident light beam. FIG.

77 is a block diagram of a conventional polarization authentication device.

78 is a configuration diagram of another conventional polarization authentication device.

79 is a configuration diagram of a liquid crystal display device of a conventional example.

(The best mode for carrying out the invention)

Based on the Example, the content of this invention is demonstrated concretely.

(Embodiment A1-1)

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

As shown in Fig. 5, the image display apparatus 101 includes an illumination optical unit 104 composed of a lamp 102 and a reflector 103, a hologram element 105 and an image display element 106, which are diffractive optical elements, and projection. The lens 107 is provided and comprised.

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 the lamp 102 is almost cylindrical, and the length of the light emitting region (arc) in the optical axis direction is about 4 millimeters. The lamp 102 is not limited to a metal halide lamp but may be a halogen lamp, a xenon lamp, an ultrahigh pressure mercury lamp, or the like.

The reflector 103 is formed such that the reflecting surface forms an object surface, and the lamp 102 has a central axis of the light emitting area substantially coinciding with the optical axis of the object surface, and the focal point of the object surface and the center of the light emitting area are substantially coincident. It is arranged. However, since the lamp 102 is not an ideal point light source, and the light emitting area has a certain size, the reflected light beam P is not a light beam that proceeds strictly in parallel.

The hologram element 105 is configured to convert the reflected light beam P as described above into a parallel light beam (plane wave) Q which is almost exactly parallel and enter the image display device 106. In other words, when the reflected light beam P is incident as the reference light, the parallel light beam Q is reproduced and output as the 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, but details thereof will be described later.

The image display element 106 includes a micro color filter in which a region for transmitting red, green, or blue light is formed for each pixel, and a liquid crystal panel for controlling the amount of light transmitted for each pixel. Luminance modulation is performed so that the luminance modulated light beam R is incident on the projection lens 107.

The projection lens 107 is configured to enlarge and project the incident light beam onto a screen (not shown).

As described above, the hologram element 105 converts the reflected light beam P from the reflector 103 into the parallel light beam Q, which is ideal even when the lamp 102 has a high output and a large light emitting area. The same luminous flux as in the case of using a point light source can be obtained. Therefore, as compared with the case where no hologram element 105 is not used, a projection image 1.2 times brighter, i.e., 1.2 times brighter, can be obtained.

Next, the hologram element 105 and its manufacturing method are explained in full detail.

The hologram element 105 has a light beam as a reference light having a wavefront substantially equivalent to the reflected light beam P (hereinafter referred to as a "real light beam") and a light beam as an object light having a wavefront substantially equivalent to the parallel light beam Q. (Hereinafter referred to as "ideal light beam") is produced by irradiating hologram material such as a photopolymer to form a two-beam interference beam. As a result, the hologram element 105 can emit the parallel light beam Q which is almost exactly parallel as described above as the object light by injecting the reflected light beam P from the reflector 103 as the reference light.

Here, the light beam and wavefront will be described briefly. In general, light can be described below (Equation 1) as a sinusoidally oscillating wave.

(Wed 1)

u = Aexpi (ωt-kr)

Where A is a plural amplitude, i is an imaginary unit, ω is an angular velocity, t is time, k is a vibration vector, and r is a position vector that determines coordinates in space.

The plane perpendicular to this vibration vector is generally called the wavefront.

The luminous flux is a concentration of a plurality of light waves (light as waves), and in an isotropic medium, the wave vector means the traveling direction of the light wave, so the wave front of the light beam is referred to as a "package of wave fronts of a plurality of light waves". define.

In addition, for example, "a wavefront substantially equivalent to the reflected light beam P or parallel light beam Q (real light beam or an abnormal light beam)" means the so-called light wave included in the reflected light beam P or parallel light beam Q. Waveguide and a collection of light waves having roughly the same wavefront ".

For example, the "light beam having a wavefront substantially equivalent to the reflected light beam P or the parallel light beam Q" is almost the same as the wavefront of the so-called light wave included in the reflected light beam P or the parallel light beam Q. Luminous flux, which is an aggregate of light waves having a wavefront.

As shown in FIG. 6, the hologram element 105 is a half mirror (S) and an ideal light beam T, which are interferences output from the real light beam generating means 110 or the abnormal light beam generating means 111, respectively. The hologram material 113 is irradiated in the same direction through 112, and an interference height is generated to form a hologram element of transmission type. As shown in FIG. 7, the real light beam S and the abnormal light beam T may be directly irradiated to the hologram material 113 without passing through the half mirror 112. In addition, as shown in FIG. 8, the real light flux S and the abnormal light beam T may be irradiated from both sides of the hologram material 113 to be formed as a Luffman type hologram element. 6 to 8, the real luminous flux generating means 110 has a lamp 102 and a reflector 103 for convenience, and the abnormal luminous flux generating means 111 is drawn to have a point light source 111a and a reflector 111b. However, this means that the actual luminous flux generating means 110 outputs a real luminous flux having a wavefront substantially equivalent to the reflected luminous flux P output from the lamp 102 through the reflector 103, while the abnormal luminous flux generating means 111 ) Is configured to output an abnormal light beam having a wavefront which is almost equivalent to the parallel light beam Q which is almost exactly parallel.

As the hologram material 113, for example, a photorefractive crystal such as a salt oil (bleaching type) or iron-doped lithium niobate, gelatin dichromate, a general hologram material of a photopolymer, and an interference height are uneven ( I) Photoresist recording as a change in change (this is formed by electron beam writing, ion beam etching, embossing, etc., if produced by calculation, etc., not by two-beam interference), photolithographic plastic, UV flexible A liquid crystal, a mixture of a liquid crystal polymer and a photoresist may be used.

Specifically, for example, the real light beam generating means 110 and the abnormal light beam generating means 111 may be ones having the following three configurations, respectively. First, the outline | summary of each structure is demonstrated.

The first configuration of the real light beam generating means 110 has the same shape as the light emitting area in the lamp 102 of the image display apparatus 101, and simulates the light emitting body using a simulated light emitting body that generates coherent light flux. The luminous flux from the luminous flux is reflected as a real luminous flux S that reflects the luminous flux from the reflector 103 of the image display apparatus 101.

The second constitution allows direct generation of light beams such as divergence angles substantially equivalent to the actual luminous flux S reflected by the reflector 103 in the first constitution without using a reflector, a simulated light emitter, or the like. will be.

In the third configuration, a master hologram is produced by interfering a real light beam S (object light) generated by the first or second configuration with a predetermined light beam (reference light). The light beam (reference light), which is the same as the predetermined light beam, is irradiated to reproduce the real light beam S (object light).

The first configuration of the abnormal luminous flux generating means 111 is to use the same simulated light emitter and reflector as the first configuration of the real luminous flux generating means 110. However, it is preferable to use a small light emitting area of an ideal lamp, i.e., a size that emulates a point light source, as a simulated light emitter and a high precision reflector.

The second configuration is to generate the abnormal light beam T directly without using a reflector, a simulated light emitter, or the like as the second configuration of the real light beam generating means 110.

The third configuration is the same as the third configuration of the actual luminous flux generating means 110, the abnormal luminous flux T (object light) generated by the first or second configuration, and the predetermined luminous flux (reference light). ) Is a master-hologram produced by interfering with).

Hereinafter, each specific configuration of the actual luminous flux generating means 110 and the abnormal luminous flux generating means 111 will be described in detail.

In the first configuration of the actual light beam generating means 110, as shown in FIG. 9, the simulated light emitting body 122 is supported by a fine needle-shaped support member (not shown) and disposed inside the reflector 121. will be. The reflector 121 has the same shape as that of the reflector 103 of the image display apparatus 101. Here, the shapes of the reflectors 103 and 121 can be set regardless of which luminous flux is output from the hologram element 105. That is, since the luminous flux actually output from the hologram element 105 in the image display apparatus 101 becomes equivalent to the abnormal luminous flux T, for example, an ellipsoidal mirror is used for the reflectors 103 and 121, and the hologram element is used. A procedure equivalent to that obtained from an ellipsoidal or spherical mirror in the hologram element 105 by outputting a parallel light beam equivalent to that obtained from a point light source and a parabolic mirror at 105, or by using a parabolic mirror at the reflectors 103 and 121 It is also possible to output the luminous flux.

The shape and position of the simulated light emitting body 122 are set in the same manner as the light emitting area in the lamp 102 of the image display apparatus 101. Specifically, for example, when the lamp 102 is a metal halide lamp as described above, the lamp 102 is columnar, and the long axis thereof is arranged to substantially coincide with the optical axis of the reflector 121. In addition, when the lamp 102 is a xenon lamp, it is substantially spherical shape, and the center is arrange | positioned so that it may be located on the optical axis of the reflector 121. As shown in FIG. In addition, the simulated light emitter 122 is made of a material having light reflectivity, and scatters the laser light U incident from the opening 121a of the reflector 121 in the reflector 121, thereby realizing the actual light flux S. It is supposed to generate. That is, although it is difficult to form the light-emitting body which generate | occur | produces coherent light beam in the same shape as the light emitting area of the lamp 102, by using the simulated light-emitting body 122 as mentioned above, it is easy to generate | occur | produce the same light beam and to make a real light flux. (S) can be obtained. As a specific material of the simulated light emitter 122, a metal material such as aluminum or stainless may be used, or a metal thin film or the like having light reflectivity may be used on the surface of glass, ceramic, or a resin material. In addition, it is preferable that the surface of the simulated light emitting body 122 has some scattering property by mechanical or chemical processing or the like. Further, the surface of the simulated light emitting body 122 may be coated with quartz, glass, or the like equivalent to a light emitting tube (casing such as a sphere made of quartz or the like) of the lamp 102.

In addition, in order to irradiate the laser beam U over the entire surface of the simulated light emitting body 122, the laser light U is irradiated, or simultaneously or sequentially irradiated from the plurality of openings 121a in the reflector 121. do. In the case of sequentially irradiating, the hologram material 113 may be subjected to multiple exposure. Also, in order to accurately perform wavefront conversion on the luminous flux emitted inside the light emitting area of the lamp 102, a plurality of simulated light emitters having a smaller appearance than that of the simulated light emitter 122 are used. 113 may be subjected to multiple exposure. As a result, the wavefront conversion efficiency can be improved. Also, among the luminous fluxes scattered by the simulated light emitter 122, the luminous flux that directly reaches the hologram material 113 without being reflected by the reflector 121 is generated, but this causes the lamp 102 to use when the image display apparatus 101 is used. It is possible to form the hologram element 105 which can be used effectively the light speed irradiated directly. That is, since the luminous flux irradiated directly from the lamp 102 has a large divergence angle, in the conventional image display apparatus, the projection lens 107 is hardly reached through the image display element 106, and thus it cannot be effectively used. According to this method, such an optical speed can be effectively used to further increase the projection efficiency. The laser light U may use any wavelength in the visible light region. However, when the hologram material 113 is subjected to multiple exposures sequentially using wavelengths corresponding to three primary colors, wavefront conversion is performed with higher efficiency. I can do it.

The second configuration of the actual light beam generating means 110 is a room in which the reflector 103 is rotated around the Z (optical axis) axis as shown in Fig. 10, for example, as shown in Fig. 10. In the case of a water mirror, for example, the luminous flux emanating at an angle in the range of luminous fluxes S1 to S2 after passing the A point of the same degree is set to be the true luminous flux S.

(Wed 2)

z = x ² / 2p + p / 2

Provided that p is a positive integer.

That is, the light emitting area of the lamp 102 is a cylindrical shape like a metal halide lamp, and has a point C (p + Δz, 0) and a point D (p-Δz, 0) centering on the focal point F (p, 0) of the object surface. ), The luminous flux emitted from the focal point F toward the point A on the object plane proceeds in a direction S0 parallel to the z-axis at the point A, and the luminous flux emitted from the points C and D is S0 and It progresses in the direction which makes the angle (DELTA) (theta) 1 or (DELTA) (theta) 2. For example, when the planar simulated light emitting surface 131 is disposed on a plane including the x axis and perpendicular to the z axis, the reflected light of the laser light irradiated from the surface side of the simulated light emitting surface 131 or the back side The actual light beam S can be obtained by forming the surface shape of the simulated light emitting surface 131 so that the transmitted light of the laser beam irradiated in the above progresses in the directions S0, S1, S2 and the like. More specifically, for example, unevenness such as saw blade shape or step shape by electron beam exposure, embossing, ion beam etching, etc., for example, a sheet-shaped resin material, a metal material, a plastic material, or a photoresist layer formed on the surface thereof. The above-described simulated light emitting surface 131 can be formed, and the hologram material 113 is formed at a real light flux S obtained by reflecting or transmitting the laser light to the simulated light emitting surface 131. The hologram element 105 can be formed by exposing.

As for the 3rd structure of the real light beam generating means 110, as mentioned above, the 2nd light beam interference height of the real light beam S generated by the said 1st structure or the 2nd structure, and the predetermined light beam is a hologram material. The master-hologram was produced by recording on the same, and the master-hologram was irradiated with the same luminous flux as the predetermined luminous flux to reproduce the real luminous flux S. FIG. By using such a master-hologram, the same hologram element 105 as in the case of performing multi-exposure with a 1st structure or a 2nd structure can be manufactured by one exposure. In addition, as the material of the master-hologram, various ones as described for the hologram material 113 of the hologram element 105 can be used.

In addition, although the 1st structure of the abnormal light beam generating means 111 uses the simulated light emitting body and a reflector like the 1st structure of the said real light beam generating means 111, it simulates a point light source as mentioned above as a simulated light emitting body. As a point of using one having a smaller size and a reflector, regardless of the shape and precision of the reflector 103 used in the actual image display apparatus 101, the point of using the reflector of the shape and precision at which a desired abnormal light beam is obtained is obtained. different. That is, when obtaining a parallel light beam as an ideal light beam, a parabolic mirror may be used and the simulated light emitting body may be arranged at the focal point of the water surface. In addition, when obtaining the luminous flux which condenses at a predetermined | prescribed point, an ellipsoidal mirror is used and a simulated light emitting body is arrange | positioned at one focal point. The spherical mirror can be used to place the simulated light emitter into the center of the sphere.

The second configuration of the abnormal light beam generating means 111 is to cause the abnormal light beam T to be generated directly without using a reflector, a simulated light emitter, or the like as described above. This is to enlarge, for example, to generate a parallel light beam, a converged light beam, a divergent light beam, and the like which are substantially planar waves.

The third configuration of the abnormal luminous flux generating means 111 records the two-beam interference height between the abnormal luminous flux T generated by the first or second configuration and the predetermined luminous flux on the hologram material, thereby master-writing The hologram was fabricated, and the master-hologram was irradiated with the same light beam as the predetermined light beam so as to reproduce the abnormal light beam T.

(Embodiment A1-2)

Another example of the image display apparatus will be described. In addition, in the following description, about the component which has the same function as the said Embodiment A1-1, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

The hologram element 105 is not limited to outputting the parallel luminous flux Q as described above, but may output the convergent luminous flux Q1 formed in the incident pupil of the projection lens 107 as shown in FIG. Such a hologram element 105 can be produced by generating the luminous flux converged toward a predetermined point by the abnormal luminous flux generating means 111.

By using the hologram element 105 which outputs the converging luminous flux Q1 as described above, the projection efficiency is further improved, and a projection image 1.5 times brighter than when the hologram element 105 is not used can be displayed. have.

(Embodiment A1-3)

As shown in FIG. 12, you may use the spherical reflector 141 and the condensing lens 142 instead of the reflector 103 of the objective mirror as mentioned above. In this case, the hologram element 105 generates the same luminous flux as the luminous flux output from the condensing lens 142 by the real luminous flux generating means 110 and simultaneously generates parallel luminous flux by the abnormal luminous flux generating means 111. It can manufacture by this and can output the parallel light beam Q2 similar to Embodiment A1-1. In addition, as in the embodiment A1-2, the abnormal light beam generating means 111 generates the light beam converging toward a predetermined point to produce the hologram element 105, and to enter the incident pupil of the projection lens 107. The converging luminous flux to be formed may be output.

(Embodiment A1-4)

In addition, as shown in FIG. 13, you may use the reflector 143 of an ellipsoidal mirror. In this case, by arranging the lamp 102 near one focal point of the ellipsoid, the reflected light from the reflector 143 becomes the luminous flux condensing near the other focal point. However, since the light emitting area of the lamp 102 has a certain size, the reflected light from the reflector 143 is not condensed to the other focal point exactly, but even with such a luminous flux, the abnormal luminous flux generating means 111 By using the hologram element 105 produced by generating a light beam converging toward a predetermined point by one, the convergent light beam Q3 formed in the incident pupil of the projection lens 107 as in Embodiment A1-2 is used. You can get it. In addition, the parallel light flux as in Embodiment A1-1 is outputted using the hologram element manufactured by generating the parallel light beam by the abnormal light beam generating means 111 in the case of using the reflector 143 of an ellipsoidal mirror as mentioned above. You may do so.

(Embodiment A1-5)

The so-called three-plate type image display apparatus which separates light source light into three primary colors of red, green, and blue, and displays full color images using three transmissive image display elements corresponding to the light of each color. An example will be described.

As shown in FIG. 14, the image display apparatus 115 is provided with the illumination optical part 104 which consists of the lamp 102 and the reflector 103, and the hologram element 105 like the embodiment A1-1. At 105, parallel light beam Q is output. The parallel beams Q are separated into three primary colors of red, green, and blue by the dichroic mirrors 152 and 153, and are red, green, and blue through the total reflection mirror 154 and the condenser lens 155. The luminance is modulated by entering the liquid crystal panels 156 to 158 corresponding to the pixels, and then synthesized by a color combining system constituted by the total reflection mirror 159 and the dichroic mirrors 160 and 161, and the projection lens 107. It is designed to enlarge and project on a screen not shown.

In the three-plate type image display apparatus 151 as described above, the optical path length is longer than that of the single-plate type. For this reason, in the conventional image display apparatus, the loss due to the divergence of the luminous flux is increased, but since the almost complete parallel luminous flux Q is obtained by using the hologram element 105 as described above, a bright projection image is obtained. Can be displayed.

(Embodiment A1-6)

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

As shown in Fig. 15, the image display device 171 is provided with an illumination optical unit 104 composed of a lamp 102 and a reflector 103, and a hologram element 105, as in the embodiment A1-1. At 105, parallel light beam Q is output. This parallel light beam Q is incident on PBS (polarization beam splitter) 173 through the total reflection mirror 172, and the light beam of randomly polarized light is converted into the light beam of almost linearly polarized light. The luminous flux converted into almost linearly polarized light is separated into luminous fluxes of three primary colors by the dichroic mirrors 175 and 176 through the lens 174, and is incident on the reflective liquid crystal display elements 177 to 179 to be modulated luminance. And synthesized by the dichroic mirrors 175 and 176, and are projected by the projection lens 107 on a screen not shown. Alternatively, three PBSs may be used.

In the reflective three-plate type image display device 171 as described above, the optical path length is also longer than that of the single plate method. However, in the conventional image display device, the projection efficiency is lower than, for example, 1 lumen / watt. In the image display apparatus 171 using the hologram element 105, high projection efficiency can be obtained at 1.8 lumens / watt.

(Embodiment A1-7)

An example of an image display apparatus further provided with an integrator together with a hologram element will be described.

As shown in Fig. 16, the image display device 181 is provided with a hologram element 105 as in the embodiment A1-1, and is provided between the hologram element 105 and the image display element 106. The integrator 184 which consists of the fly's eye lens 182 and the 2nd fly's eye lens 183 is provided.

The first fly's eye lens 182 and the second fly's eye lens 183 are each formed with a small lens group. That is, each microlens of the first fly's eye lens 182 forms an image of a light emitting region (light emitting body) on a corresponding microlens of the second fly's eye lens 183, respectively. In addition, each microlens of the second fly's eye lens 183 is formed by polymerizing an image of each microlens of the first fly's eye lens 182 onto the entire surface of the image display element 106. As a result, a plurality of luminous fluxes output from the illumination optical unit 104 are divided, and polymerized on the image display element 106, respectively, to reduce light quantity stains at the center and periphery of the display image. .

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 generating means 110, and at the same time, the abnormal light beam generating means 111. It is produced by generating parallel light beam by

Here, the chromatic aberration and magnification aberration may occur in the hologram element 105 actually produced, and the parallel luminous flux Q output from the hologram element 105 is limited to a perfectly ideal parallel luminous flux. Not necessarily, the conversion efficiency is not 100%. That is, most of the reflected light beam P output from the illumination optical unit 104 is converted into the ideal parallel light beam, but some of the light beams are included in the parallel light beam Q as they are. Therefore, by combining with the integrator 184 or the like as used in a conventional image display apparatus that does not have the hologram element 105 as described above, the luminous flux or the like which is not converted into the parallel light flux by the hologram element 105 is also effective. The aberration and wavefront conversion loss of the hologram element 105 can be compensated for.

Therefore, as compared with the conventional image display apparatus in which only the integrator 184 is provided without providing the hologram element 105, a projection efficiency of 1.4 times higher can be obtained. In addition, the ambient light quantity ratio (ratio between the brightness of the center portion of the screen and the brightness of the peripheral portion in the case of displaying by the back signal) can be obtained at a high value of 70% or more equivalent to that of the prior art.

(Embodiment A1-8)

As an image display element, an example in which a reflective deflection element as disclosed in, for example, US Patent No. 5096279 is used 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, an integrator 184 like Embodiments A1-7, and a reflective deflection element. An image display element 192 and a projection lens 107 are provided. The hologram element 105 is provided between the first fly's eye lens 182 and the second fly's eye lens 183 of the integrator 184, while the integrator 184 and the image display device ( Between the 192, a lens 193 is provided in which the luminous flux output from the integrator 184 is a parallel luminous flux.

As the lamp 102, a 400-watt metal halide lamp is used, and a reflecting mirror is used for the reflector 103. The shape of the light emitting region of the 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 arranged 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 is substantially coincident with the optical axis of the reflector 103.

The hologram element 105 is output from the illumination optical unit 104 by the real light beam generating means 110, and generates a light beam having a wavefront that is substantially equivalent to the light beam passing through the first fly's eye lens 182. The abnormal light beam generating means 111 produces the light beam passing through the first fly's eye lens 182 or the light beam equivalent to this.

The lens 193 is made to enter the image display element 192 by making the light beam polymerized by the microlenses of the second fly's-eye lens 183 into the incident light beam of the lens 193 as a parallel light beam.

The image display element 192 is configured to 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 configuration, the luminous flux output from the first fly's eye lens 182 is incident on the microlenses (effective area) of the second fly's eye lens 183 accurately by the hologram element 105. Is converted to the speed of light. That is, when the hologram element 105 is not provided, the light emitting area of the lamp 102 has a certain size, so that it does not enter each microlens of the second fly's eye lens 183. Compared to the case where a light beam is likely to be generated, the hologram element 105 is provided, so that the correct parallel light beam (plane wave) is converted into a light beam having a wavefront that is almost equivalent to that of passing through the first fly's eye lens 182. And reliably enters each of the microlenses of the second fly's eye lens 183. That is, almost all luminous flux emitted from the lamp 102 can be incident on the effective area of the second fly's eye lens 183, and light loss can be reduced to improve light utilization efficiency. Specifically, for example, when an image display element is used for displaying a monochrome image without a color filter as a mite, the hologram element (as described above) is used in comparison with the conventional configuration in which the projection efficiency was 4 lumens / watt. 105), a projection efficiency of 8 lumens / watt can be obtained.

(Embodiment A1-9)

An example of an image display apparatus in which the polarization conversion element 202 is further provided in the configuration of the above-described embodiments A1-7 will be described.

As shown in FIG. 18, the image display apparatus includes a polarization conversion element 202 and a condenser lens 203 disposed between the second fly's eye lens constituting the integrator 184 and the liquid crystal display element 106. It is. As the image display element 106, for example, a transmissive liquid crystal panel is used, and as the lamp 102, a 100 W ultra-high pressure mercury lamp and a reflector 103 are used.

For example, as shown in FIG. 19, the polarization conversion element 202 further includes a plurality of prismatic bodies 204 to which a pair of triangular prisms are bonded to the flat plate, and a plurality of prismatic bodies. The polarization surface rotating means 205 is provided for every 204. The polarization separator 206 is formed on the bonding surface of the triangular prism. The polarization splitting film 206 is made of, for example, a multilayered film of a dielectric material, and transmits incident unpolarized light P polarized light (polarized light whose polarization direction is parallel to the surface of the drawing) and S polarized light (polarized light direction). Polarized light perpendicular to the surface of the drawing. In addition, the polarization plane rotating means 205 has a function of rotating the polarization plane of the incident light beam by approximately 90 °, and is generally made of an optical material having a phase difference of almost half of the incident wavelength.

The polarization conversion element 202 is such that the main body 204 without the polarization plane rotating means 205 corresponds to each lens constituting the second fly's eye lens 183 of the integrator 184. It arrange | positioned, and the light beam condensed by each 2nd fly-eye lens by the 1st fly-eye lens 49 is made to inject into the main body 204 corresponding to the said 2nd fly-eye lens. The light beam incident on the main body 204 is emitted by passing only the P-polarized light through the polarization separation film 206, while the S-polarized light is reflected by the polarization separation film 206, and the polarization of the adjacent main body 204 After the reflection in the separation membrane 206, the polarization plane rotating means 205 is converted to P-polarized light and output. That is, in the polarization conversion element 202, the luminous flux in which the unpolarized light from the lamp 102 matches the P-polarized light is emitted.

Here, the first fly's eye lens 182 needs to focus the incident light beam on the main body 204 where the polarization plane rotating means 205 is not provided through the second fly's eye lens 183. However, since the hologram element 105 is provided, even when the light emitting area of the lamp 102 is large, the first fly-eye lens 182 can reliably condense as described above. The effect of improving the projection efficiency by the polarization conversion element 202 can be further increased to display a bright image.

That is, in the conventional image display apparatus, even when the output of 100 watts and the light emitting area is considerably small in the shape of 1.45 mm is used as the lamp 102, for example, the polarization conversion element 202 is not provided. Compared with the light emitting area, which is only about 1.5 times brighter, and a high output lamp having a large light emitting area is used in advance, the increase in the projection efficiency due to the presence or absence of the polarization conversion element 202 is smaller, and only about 1.2 times brighter. It was enough. On the other hand, since the hologram element 105 is provided as mentioned above, since the wave front of the light beam which passed through the hologram element 105 becomes a substantially planar wave as mentioned above, most of the luminous flux is a 2nd fly-eye lens. Since the incident light can be incident on only the predetermined square body 204 through 183, for example, it is possible to make it 1.8 times brighter than when the polarization conversion element 202 is not provided. However, even when a large light emitting area is used, for example, a 400-watt metal halide lamp, a 2-kilowatt xenon lamp, or the like, the wavefront of the light beam output from the pologram element 105 is the wavefront of the light beam when a point light source is used. Since it is almost the same as the above, a large improvement in the projection efficiency can be obtained by providing the polarization conversion element 202. Specifically, even when the xenon lamp is used, the projection efficiency can be increased to 5 lumens / watt, and an image display apparatus having a high light output of 10,000 lumens can be constructed.

The same effect can be obtained when various polarization conversion elements are used or when the polarization conversion elements are arranged at different positions. For example, Japanese Patent Laid-Open No. 8-234205 or Japanese Patent Laid-Open No. 6-202094 in which the polarization conversion element 202 is disposed on the lamp 102 side of the first fly-eye lens 102. The same effect can be obtained also when using the polarization conversion element disclosed in 4 (B) etc.

(Embodiment A2-1)

An example of an image display apparatus provided with a reflective hologram element for converting a light flux output from an integrator into a parallel light flux will be described.

As shown in FIG. 20, the image display device 211 includes an illumination optical unit 104 made of a lamp 102 and a reflector 103, a first fly's eye lens 212, and a first lens, as in the embodiment A1-1 and the like. An integrator 215 composed of two fly-eye lenses 213 and a folding mirror 214 is provided. The integrator 215 has the same function as the integrator 184 of Embodiments A1-7, and ensures uniformity in brightness of the projected image. The luminous flux output from the integrator 215 is divided into luminous fluxes of three primary colors by the dichroic mirrors 152 and 153, and the red, green, and blue pixels are described later through the reflective hologram elements 216 to 218. After being incident on the liquid crystal panels 219 to 221 corresponding to the light source, the luminance is modulated, the color is synthesized by the dichroic mirrors 160 and 161, and the projection lens 107 enlarges the projection onto a screen (not shown). .

The image display elements 219 to 221 include a microlens having a microlens corresponding to each pixel, and a liquid crystal panel for controlling the amount of light transmitted through each pixel. The light is focused on the effective area.

The hologram elements 216 to 218 convert the luminous flux incident from the integrator 215 through the dichroic mirrors 152 and 153 into parallel luminous fluxes and output them to the image display elements 219 to 221. Therefore, the luminous flux incident on the microlens is surely condensed in the effective area of the liquid crystal panel, and since almost all of the incident light is used, the substantial aperture ratio is greatly increased to improve the projection efficiency and uniformity of the brightness of the projection image. You can.

Specifically, for example, when a liquid crystal panel having an aperture ratio of about 56% having a pixel dimension of 1024 x 768 formed at a diagonal dimension of 1.3 inches and a super-pneumatic mercury lamp of 100 W is used, the microlenses and the hologram elements 216 to 218 are also used. The projection efficiency when not in use is 5 lumens / watt, and the projection efficiency when only a microlens is used is 6 lumens / watt, but by providing the hologram elements 216 to 218 as described above, 8 lumens is provided. High throw ratios can be achieved with / watts. This corresponds to an improvement in the actual aperture ratio from 56% to about 90%. Also, even when a liquid crystal panel having a large number of pixels at the same size, for example, 1280x1024 pixels or more pixels (for example, 1920x1080 pixels) was used, the projection efficiency hardly changed. In addition, by providing a polarization converting element having polarization separation means and polarization plane rotating means in the illumination optical system, it is possible to realize an extremely high projection efficiency of 12 lumens / watt.

The above-described hologram elements 216 to 218 can be produced in the same manner as the hologram elements 105 of the above embodiments A1-1. That is, in the actual image display apparatus 211 as the reference light, a light beam having a wavefront equivalent to the light beam incident on the hologram elements 216 to 218, and parallel to cause the image display elements 219 to 221 as the object light to enter. It is produced by recording a two-beam interference height with a light flux having a wavefront equivalent to the light flux on a hologram material such as a photopolymer.

Specifically, for example, when manufacturing the hologram element 217 for green, as shown in FIG. 21, the integrator 215, the dichroic mirrors 152 and 153, and the hologram material 127 'are actually made. The same optical path as that of the image display device 211 is formed, and the beam light output from the laser 231 is enlarged by the beam beam expander 232, and then the two beams are beamed by the beam splitter 233. The light beam V is incident on the integrator 215 through the folding mirror 234 while the light beam V is incident on the hologram material 217 '. Here, the wavelength of the laser light is preferably included in the wavelength band of each of the three primary colors incident on the hologram in the actual image display device 211 (in this case, green), and in this case, the diffraction efficiency of the hologram element The influence of wavelength dispersion can be minimized, and the diffraction efficiency of the hologram element can be increased. As a result, a two-beam interference height is formed between the light beam having a wavefront equivalent to the wavefront of the light beam incident at the position where the hologram element 217 is disposed and the plane wave, and the dichroic mirror of the image display device 211 ( When the light beam after color separation by 153 enters, the hologram element 217 which is converted into parallel light beam and outputs to the image display element 220 is obtained.

In the case where a condensing lens, a relay lens, a deflection converting element, or the like is provided in an actual image display device, these elements may also be disposed in the optical path of the light beam V. FIG.

In addition to the above, the hologram elements 216 to 218 can be manufactured by various configurations as described in the above embodiments A1-1.

As described above, the image display apparatus of the present invention is characterized by improving the projection efficiency by injecting the illumination light beam after color separation into the image display element through the hologram elements 216 to 218 according to the present invention. In that,

Regardless of the kind of the optical modulation material of the image display element, the optical modulation method, the material for forming the driving element, and the driving method, the same effect as the image display device having the configuration shown in FIG. 1 can be obtained.

In addition, the structure of an optical system is not limited to the said structure, Various deformation | transformation according to the meaning of this invention is possible.

(Embodiment A2-2)

An example in which a dichroic prism is used for synthesizing a luminous flux of each luminance-modulated color will be described.

As shown in Fig. 22, the image display device 231 replaces the dichroic prism 235 in place of the dichroic mirrors 160 and 161 as compared to the image display device 211 of the embodiment A2-1. The installed points and the folding mirrors 232 to 234 differ in that the light paths are configured to be different.

That is, when the white light beam is incident on the dichroic mirror 152 through the integrator 215 in the lamp 102, the light flux of the red component is reflected among the incident light fluxes, and the green and blue light fluxes are transmitted. The red light beam enters the reflective hologram element 216 through the folding mirrors 233 and 234, is converted into a substantially parallel light beam, and then displays a red component of the display image (liquid crystal panel) 219. ) And is luminance modulated. The green and blue light beams passing through the dichroic mirror 152 enter the dichroic mirror 153 through the folding mirror 232, and the green light beams are reflected to transmit only the blue light beams. When the green light beam and the blue light beam are reflected by the reflective hologram elements 217 and 218, respectively, the image display elements (liquid crystal panels) 220 and 221 are converted into light beams that are substantially parallel to display respective color components of the display image. Is incident on and is modulated. The luminous flux of each of the modulated colors is synthesized by the dichroic prism 235, and is projected by the projection lens 107 to the screen not shown.

Also in the image display apparatus 231 as described above, as in the embodiment A2-1, the non-parallel luminous flux through which the output luminous flux from the lamp 102 propagates through the integrator 215 or the like is used as the hologram elements 216 to 218. Is converted into a substantially parallel luminous flux, and then enters the image display elements 219 to 221, and the microlens makes it possible to inject light only into the opening of each pixel in the liquid crystal panel. It becomes possible to make high.

Specifically, for example, when a liquid crystal panel having an aperture ratio of about 40% having a pixel of 1024 x 768 formed at a diagonal dimension of 0.9 inch and a high-pressure mercury lamp of 100 W is used, the microlenses and the hologram elements 216 to 218 are used. The projection efficiency when not in use is 3.6 lumens / watt, and the projection efficiency when using only a microlens is 4.3 lumens / watt, compared with that of the hologram elements 216 to 218 as described above. High wattage efficiency can be achieved with / watts. This corresponds to a substantial increase in aperture ratio from 40% to about 90%. In addition, even when a liquid crystal panel having a large number of pixels of the same size, for example, 1280x1024 pixels or more pixels (for example, 1920x1080 pixels) was used, the projection efficiency hardly changed. In addition, by providing a polarization converting element having a polarization separating means and a polarization plane rotating means in the illumination optical system, it is possible to realize an extremely high projection efficiency of 12 lumens / watt.

(Embodiment A 2-3)

An example of an image display apparatus which can effectively use the light speed transmitted without being reflected by the reflective hologram element will be described.

As shown in FIG. 23, the image display device 241 is mainly a total reflection mirror 242 or 243 on the rear surface side of the hologram elements 216 to 218, as compared with the image display device 231 of the embodiment A2-2. The dichroic mirror 245 is provided in a different point.

That is, when the white light beam is incident on the dichroic mirror 244 through the integrator 215 in the lamp 102, the light flux of the blue component of the incident light flux is transmitted, and the light flux of the other wavelength band (red component and green color) is transmitted. Component, i.e. yellow light flux) is reflected.

The blue light beam is mainly reflected by the blue hologram element 218 and converted into a parallel light beam, and then enters the blue image display element (liquid crystal panel) 221 and is luminance-modulated. The blue light beam transmitted without being reflected by the hologram element 218 is reflected by the total reflection mirror 243, and again passes through the hologram element 218 for blue and enters the image display element 221 again. That is, the speed of light transmitted through the hologram element 218 is effectively used.

In addition, the green light beam of the yellow light beam reflected by the dichroic mirror 244 is reflected by the hologram element 217 for green and simultaneously converted into the parallel light beam, and then enters the image display device 220 for green light. The luminance is modulated. In addition, the green light beam transmitted without being reflected by the hologram element 217 is reflected by the dichroic mirror 245, and again passes through the hologram element 217 for green, and is also transmitted to the image display element 220. Enter.

In addition, the red light beam passing through the dichroic mirror 245 enters the red hologram element 216 through the relay lenses 246 and 248 and the total reflection mirror 247 for optical path length compensation, and is mainly reflected. At the same time, after being converted into parallel light beams, the light is incident on the red image display element 219 and modulated with luminance. In addition, the red light beam transmitted without being reflected by the hologram element 216 is reflected by the total reflection mirror 242, and again passes through the hologram element 216 for red and enters the image display element 219 again. .

The luminous flux of each of the luminance-modulated colors is synthesized by the dichroic prism 235 and is projected by the projection lens 107 on a screen not shown.

As described above, the total reflection mirrors 242 and 243 or the dichroic mirror 245 are provided on the rear surface side of the hologram elements 216 to 218, thereby reflecting them as parallel light beams by the hologram elements 216 to 218. Instead of this, the light speed and most of the light beams transmitted through the hologram elements 216 to 218 can be incident on the image display elements 219 to 221. Such a luminous flux is not converted into a parallel luminous flux, but is used for projecting an image, so that a higher projection efficiency can be obtained than when only the hologram elements 216 to 218 are used.

Specifically, for example, in the case of using a liquid crystal panel having an aperture ratio of about 40% having a pixel of 1024 x 768 at a diagonal dimension of 0.9 inches and a 100W ultra-high pressure mercury lamp, microlenses and hologram elements 216 to 218 are also used. If not, the projection efficiency is 3.6 lumens / watt, and the projection efficiency when only the microlenses are used is 4.3 lumens / watt, whereas by installing the hologram elements 216 to 218 as described above, 10 lumens / watt is used. High wattage efficiency can be achieved with watts. This corresponds to a substantial increase in aperture ratio from 40% to about 90%. In addition, even when using a liquid crystal panel having a large number of pixels of the same size, for example, 1280x1024 pixels or more pixels (for example, 1920x1080 pixels), the projection efficiency hardly changed. Further, by providing a polarization converting element having polarization separation means and polarization plane rotating means in the illumination optical system, it is possible to realize an extremely high projection efficiency of 12 lumens / watt.

As the mirror provided on the rear side of the hologram element 217, it is necessary to transmit the red light beam, and thus, as described above, the green reflection and the red-transmissive dichroic mirror need to be used. As the mirror provided on the back surface side of 216 and 218, a total reflection mirror (usually formed by forming an aluminum thin film on a glass substrate and optionally applying an antireflection coating) may be used, and a red light beam may be used. Alternatively, a dichroic mirror that reflects a blue light beam may be used.

In addition, the configuration in which the reflecting mirror is provided on the rear side of the hologram element as described above may be applied to the above-described embodiment A2-1 or embodiment A2-2 or the following image display device, and furthermore, the projection efficiency can be further increased. have.

(Embodiment A2-4)

As an image display element, an example of an image display apparatus using a dichroic prism for color separation of a white light beam while using a polarization modulation type liquid crystal display panel as a reflection type will be described.

In the image display device 259 of the present embodiment A, as shown in FIG. 24, the output light flux from the lamp 102 is reflected by the reflector 103 as in the image display devices described in Embodiments A2-1-2-3. The output light beam after reflection is propagated to the image display elements 260 to 262 through the first fly's eye lens 212 and the second fly's eye lens 213.

Between the second fly's eye lens 213 and the image display elements 260 to 262, a dichroic prism 263 for color separation, hologram elements 264 to 266, and a PBS (polarizing beam splitter) 267 to 269) are installed. That is, the white output light flux in the lamp 102 is color-separated by the dichroic prism 263 into luminous fluxes of three primary colors of red, green, and blue, and each of the color-separated luminous fluxes corresponds to the corresponding hologram elements 264 ˜. 266) is converted into a desired luminous flux, and linearly polarized light having a predetermined polarization plane is incident on the reflective image display elements 260 to 262 by the PBSs 267 to 296 so that the polarization direction is modulated. have.

The luminous flux of each primary color whose polarization direction is modulated in the image display elements 260 to 262 is visualized again through the PBSs 267 to 269, and is projected on the screen (not shown) by the projection lens 107.

The hologram elements 264 to 266 can be produced by basically recording the two-beam interference height between the reference beam and the object beam in general hologram materials such as a photopolymer, as in the embodiments A2-1. Here, the hologram elements 264 to 266 may be made so that the luminous flux converted and outputted by the incident luminous flux becomes almost parallel luminous flux as in Embodiments A2-1 to 2-3, or the polarization separation characteristic of the PBS does not significantly decrease. The incidence angle of the precision may be a small convergent light flux. As a result, both of high projection efficiency and high contrast can be realized while minimizing the apparatus for the reasons described below.

In general, the F value of the illumination optical system composed of a lamp, a reflector, a condenser lens, a relay lens, an integrator, a polarization conversion element, and the like is generally set to coincide with the F value of the projection lens. While the efficiency is high, the maximum incident angle of the light beam incident on the liquid crystal panel and the PBS becomes large. Here, PBS is generally configured to form a dielectric multilayer film on a glass substrate so that incident light is separated into P-polarized light and S-polarized light, but its polarization separation characteristic depends on the incident angle of incident light, and shifts from the reference incident angle at design time. Accordingly, the polarization separation characteristic is lowered. Therefore, in the image display apparatus using the reflective liquid crystal panel as described above, when the F value is small, the contrast is likely to be lowered. Therefore, in order to improve the contrast, when the incidence angle is reduced by the relay lens of the illumination optical system, the illumination area becomes large due to the principle of luminance invariance in so-called geometric optics. It is necessary to use it, resulting in the enlargement of an apparatus. On the other hand, by using a hologram element as in the present embodiment A, the illumination area can be made small even if the incident angle is made small so that the polarization separation characteristic of the PBS does not significantly decrease. Therefore, an image display apparatus can be configured in which the projection efficiency is high and the contrast is not reduced while the apparatus is miniaturized by using a liquid crystal panel having a small screen size.

Specifically, for example, when a liquid crystal panel having an aperture ratio of about 75% having a pixel of 1024 x 768 formed at a diagonal dimension of 0.9 inches and an ultra-high pressure mercury lamp of 100 W is used, the hologram elements 264 to 266 are not used. In the image display apparatus, when the F value of the projection lens 107 and the illumination optical system is 4 in order to secure the contrast, the projection efficiency is about 2 lumens / wattrocontrast is 200: 1 and when the F value is 3, 4 lumens It was possible to brighten with / watts, but the contrast was reduced to 100: 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, the projection efficiency of about 4.3 lumens / watt can be realized, and the F value is larger than the PBS. The incidence angle is small), and the contrast can be improved to 800: 1.

The image display elements 260 to 262 are not limited to a liquid crystal panel but may be a reflection type image display element that is a polarization modulation type that reflects and outputs incident linearly polarized light after modulating its polarization direction. There are no restrictions on materials, light modulation, pixel driving, and the like.

The image display device constructed in this embodiment A is a 3PBS system using three PBSs, but a 1PBS system using one PBS can also be configured.

In order to improve the contrast of the projected image, a prepolarizer (PPBS) may be provided between the PBS and the hologram element of the present invention.

(Embodiment A2-5)

An example of a single-plate type image display apparatus having a dichroic mirror disposed at different angles with respect to an optical axis and an image display element having a micro lens array or the like will be described.

As shown in Fig. 25, the image display apparatus 280 includes two dichroic mirrors 281 and 212, one total reflection mirror 283, each dichroic mirror 281 and 282, or a total reflection mirror 283. Color separation means 287 having hologram elements 284 to 286 provided on the surface side of the < RTI ID = 0.0 >), < / RTI > and an image display element 288 having an optical path conversion number and a liquid crystal panel for varying the optical path of the incident light beam according to the incident angle. have. The basic structure and operation of this image display device 280 are described in the Nikkei Electronics, January 30, 1995, page 169, page 173, Japanese Patent Application Laid-Open No. 8-292506, or Japanese Patent Application Laid-open No. 9-105899. It is the same as described in 14, etc., and differs in that the said hologram elements 285-287 are provided.

That is, the dichroic mirrors 281 and 282 and the total reflection mirrors 283 are disposed at different angles with respect to the optical axis, respectively, so that the output light flux of the white light at the lamp 102 is the light flux of three primary colors of red, green, and blue. Each of the color-separated and color-separated light beams is made to enter the optical path changing means of the image display element 288 at different incident angles. In this image display device 280, only the light beams passing through the hologram elements 284 to 286 are reflected by the dichroic mirror 281 or the like as described above, but this will be described later. As the 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 corresponds to different colors in the liquid crystal panel according to the incident angle. It is made to enter into a pixel.

With the above configuration, when a white light beam is incident from the lamp 102 to the color separation means 287 through the reflector 104 and the integrator 215, the light flux of the blue component of the incident light flux is for blue. After being reflected by the hologram element 284 and converted into a parallel light beam, it is incident on the image display element 288. The blue light beam transmitted without being reflected by the hologram element 284 is reflected by the dichroic mirror 281 for reflecting the blue light beam, and again passes through the blue hologram element 284 and is also an 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 the blue beam, and is then reflected by the hologram element 285 for green and converted into parallel luminous flux. And the green light beam passing through the hologram element 285 is reflected by the dichroic mirror 282 for reflecting the green light beam and also enters the image display element 288.

The hologram for red after passing through the hologram elements 284 and 285 for the luminous flux of the red component, blue and green, and the dichroic mirrors 281 and 282 for reflecting the blue beam and reflecting the green beam. The red light beam reflected by the element 286 and converted into parallel light beams and incident on the image display element 288 and transmitted through the hologram element 286 is reflected by the total reflection mirror 283, which is also an image display element ( 288).

The luminous flux of each color incident on the optical path converting means of the image display element 288 is incidentally modulated by incident light on the pixels corresponding to the different colors in the liquid crystal panel according to each incident angle, and is not shown by the projection lens 107. Not projected on the screen magnified. Here, since the luminous flux of each color reflected by the hologram elements 284-286 is converted into the parallel luminous flux as mentioned above, it concentrates to the effective area | region of the pixel corresponding to each color in a liquid crystal panel, respectively reliably. Therefore, the effective aperture ratio can be extremely increased, and at the same time, it becomes possible to control so-called cross talk to a minimum when a part of the luminous flux of each primary color enters a pixel corresponding to another primary color. Therefore, the structure of the optical system is simple, and it is possible to display a clear image without mixing color while utilizing the feature of the single plate type of low cost, and further improve the uniformity of the projection efficiency and the brightness of the projection image.

Specifically, for example, when a liquid crystal panel 288 having an aperture ratio of about 40% having a pixel of 640 x 480 x 3 formed at a diagonal dimension of 1.3 inches and a high-pressure mercury lamp of 100 W are used, hologram elements 284 to 286 are used. The projection efficiency in the case of not using) is only 1.5 lumens / watt, whereas by installing the hologram elements 284 to 286 as described above, a high projection efficiency can be obtained at a single plate type and 4 lumens / watt. Further, by providing a polarization converting element having polarization separation means and polarization plane rotating means in the illumination optical system, it is possible to realize an extremely high projection efficiency of 8 lumens / watt.

(Embodiment A3-1)

An example of an image display apparatus provided with a diffraction optical element will be described instead of an integrator having a first fly's eye lens and a second fly's eye lens.

As shown in Fig. 26, the image display apparatus includes a lamp 102, a reflector 103, a diffractive optical element 301, an aspherical auxiliary lens 302, an image display element 303, and a projection lens 107. Installed and configured. That is, the luminous flux emitted from the lamp 102 is reflected by the reflector 103 and is incident on the diffraction optical element 301. The luminous flux diffracted for each diffraction region 301a of the diffraction optical element 301 described later is an auxiliary lens. The brightness is modulated by superimposing on the image display area of the image display element 303 through 302, and is projected by the projection lens 107 to be enlarged on a screen (not shown).

As the lamp 102, for example, an ultra-high pressure mercury lamp having a rated output of 120 watts is used. In addition, various things as described in Embodiment A1-1 can be used, without being limited to said lamp. Here, although the light emitting area of the lamp 102 is more preferable, even if the light emitting area is relatively large, since the relative effect of the present invention can be obtained, for example, a light emitter such as a high output xenon lamp or a high output metal halide lamp You can also use a lamp that is large enough in advance.

As the reflector 103, for example, a cotton mirror is used, but an ellipsoidal mirror, a spherical mirror, or the like may be used. The position where the lamp 102 is installed is preferably set so that the light emitting area of the lamp 102 is located near the focal point in the case of a parabolic mirror, and in the case of an ellipsoid mirror, in the vicinity of the first focal point, and in the case of a spherical mirror It is preferable to set so that it may be located in the vicinity.

The auxiliary lens 302 is provided to secure the telecentricity of the incident light beam to the image display element 303 and to reduce the design burden of the projection lens, that is, to alleviate the constraints such as the F value. However, it is not necessary to install it if there is a design margin in the F value of the projection lens.

As shown in Fig. 27, the diffraction optical element 301 has a circular shape corresponding to the cross-sectional shape of the light beam incident on the reflector 103 when viewed from the optical axis direction, and an inner region of the diffraction optical element 303 It is divided into a plurality of square diffraction areas 301a ... similar to the image display area. Each of the diffraction regions 301a diffracts the incident light beams as described above, so that the diffraction regions 301a are incident on the entire surface of the image display region of the image display element 303. That is, the luminous flux output from each diffraction area 301a is superimposed on the image display element 303, so that light spot staining at the center and periphery of the display image can be reduced.

In addition, the shape of each diffraction area | region 301a may not necessarily be rectangular shape similar to the image display element 303, and may not be the same size or shape mutually. In addition, although the magnitude | size and number of the diffraction area | region 301a are typically shown in FIG. 26 and FIG. 27 for convenience, it is not specifically limited. That is, when the luminous flux output from each diffraction area 301a is largely superimposed on the image display area of the image display element 303, the effect of light quantity stain reduction is obtained. However, in general, the larger the number of diffraction regions 301a can improve the uniformity of the brightness of the projected image, and also increase the square conversion efficiency (square opening ratio) to increase the projection efficiency and make it brighter. An image can be displayed. In addition, it is relatively easy for the microregion 301a to have a shape similar to that of the image display element 301 so that the output light flux in each diffraction region 301a is superimposed on the image display element 303. Done. The light beams may be superimposed on a part of the area on the image display element 303 by generating a diffraction action in the area 301b at the periphery of the rectangular diffraction area 301a. In this case, the substantially short conversion efficiency can be 100%, and it becomes possible to display a brighter image.

In addition, the uniformity of the brightness of the projected image may be further improved by slightly shifting the region where the output light flux from the diffraction optical element in the image display element 303 is incident for each diffraction region 301a.

As a specific diffraction structure of the diffractive optical element 301, for example, a surface relief diffraction grating having a cross-sectional shape in the shape of a saw blade can be used. In addition, the tooth shape may be a multilevel diffraction grating or the like approximating a step shape. The saw blade shape and the like can be determined by calculation of an optical image or the like.

The diffraction optical element 301 as described above can be manufactured by, for example, a general semiconductor process using an electron beam drawing method, and is easy to mass-produce. Therefore, the diffraction optical element 301 can be manufactured in comparison with an integrator using a conventional fly's eye lens. Can be easily made to about 1/10 or less. Therefore, the integrator which occupies most of the manufacturing cost of the optical element together with the projection lens 107 becomes inexpensive, so that it is easy to suppress the manufacturing cost of the entire image display apparatus to, for example, about 60% of the conventional one. can do.

In addition, the diffraction optical element 301 may be manufactured by forming a hologram element with a two-beam interference height as described in Embodiment A below.

As the image display element 109, various types of transmissive type, such as a transmissive liquid crystal panel, can be used. Here, for example, as disclosed in Japanese Patent Application Laid-Open No. 1-281426, Japanese Patent Application Laid-open No. Hei 3-140920, Japanese Patent Application Laid-Open No. 4-251221, and the like, a microlens corresponding to each pixel is disclosed. May be used to achieve an effective increase in aperture ratio by converging the incident light beam to the image display element near the opening (effective region) of the pixel. For example, a high projection efficiency (light utilization efficiency) can be obtained even when the aperture shape of the reflector 103 is set small so as to reduce the size of the device. That is, in the integrator using the conventional fly-eye lens, each single lens of the first fly-eye lens and each single lens of the second fly-eye lens are set to correspond. However, when the opening shape of the reflector is small, the deviation from the parallel light of the light beam output from the reflector tends to be large, and in this case, crosstalk tends to occur between the individual lenses of the fly's eye lens. Therefore, the image of the first lens array becomes considerably larger than the image display element, and the image display element cannot be effectively illuminated.

On the other hand, in the case where the diffraction optical element 301 is used as described above, since the diffraction light beams by the diffraction regions 301a of the diffraction optical element 301 are directly incident on the liquid crystal display element, two fly-eye lenses are used. Crosstalk does not occur as in the case of use, and therefore, even if the deviation from the parallel light of the light beam output from the reflector becomes large, the illumination area of the image display element 303 slightly shifts even if the parallelism of the light beam decreases slightly. It is only the degree which is shift | deviated or widened, and since the effect of actually increasing the aperture ratio by a micro lens is obtained suitably, high projection efficiency is obtained. In the case of using a light source having a low parallelism of the light flux output from the reflector, that is, a lamp having a relatively large light emitting area, the area where the image display element is illuminated is set smaller than the image display area when the ideal parallel light flux is output. The whole of the image display element may be illuminated by the deviation due to the output light flux being not parallel light flux.

As described above, by using the diffractive optical element in place of the integrator having the fly's eye lens, light spot staining on the center part and the peripheral part or the like in the display image can be reliably reduced, and the projection efficiency can be improved. Can be. Regarding the projection efficiency, for example, in the conventional image display apparatus, the projection efficiency is only about 5 lumens / watt, whereas in the image display apparatus, it is possible to obtain high efficiency at 7.5 lumens / watt.

In addition, since the opening shape of the reflector can be reduced without causing a decrease in the brightness of the display image, it is possible to easily downsize the image display apparatus. Specifically, the opening diameter of the conventional reflector can be about 50 mm, for example, and the optical axis direction can also be about 1/2 of the conventional size. In addition, the F value of the projection lens can be reduced, and the distance between the diffractive optical element and the image display element can be shortened to further reduce the size.

(Embodiment A3-2)

In the image display apparatus using the diffraction optical element as in Embodiment A3-1, the light source light is separated into three primary colors of red, green, and blue, and three transmissive image display elements corresponding to the light of each color are provided. An example of a so-called three-panel image display apparatus for displaying a full color image using the following will be described.

In the image display device of the present embodiment A, as shown in FIG. 28, after reflecting the output light flux of the lamp 102 to the reflector 103, the image display devices 314 to 316 of the image display device 301 are reflected through the diffraction optical element 301. It is supposed to be an illumination beam. The diffractive optical element 301 is the same as the embodiment A3-1. That is, a plurality of diffraction regions are formed, and the output light fluxes of the diffraction regions are separated into three primary colors by the dichroic mirrors 317 and 318, respectively, and then image display elements 314 to 316 which display images of each color. ) So that they overlap.

More specifically, of the white light flux output from the diffraction optical element 301, only the blue light flux is transmitted by the dichroic mirror 317, and the other wavelength components are reflected. The light flux of the blue component is incident on the image display element 314 for displaying a blue image through the reflection mirror 319. Of the reflected light of the dichroic mirror 317, the green component is reflected by the dichroic mirror 318 and enters the image display element 315 for green. The red component enters the image display element 316 for red display through the relay lenses 320 and 321 and the reflection mirrors 322 and 323. The luminous flux of each color incident on each of the image display elements 314 to 316 is luminance-modulated and then synthesized by a dichroic prism 324 for color synthesis, and a screen (not shown) by the projection lens 107. Is enlarged and projected on.

In addition, as shown in FIG. 29, you may make it synthesize | combine with the dichroic mirrors 339 and 340, without using a dichroic prism. That is, after collecting the output light flux of the lamp 102 by the reflector 103, the diffraction optical element 301 as in Embodiment A3-1 is diffracted and separated for each diffraction region, and the output light flux of each diffraction region is dichroic. The brightness is modulated by overlapping on the image display elements 314 to 316 through the blade mirrors 333 and 334 and the reflection mirror 335, and output light beams of the image display elements 314 to 316 are dichroic mirrors 339 and 340. ) And a full color image are similarly displayed by magnified projection on a screen (not shown) by the projection lens 107.

Even in the image display apparatus of the present embodiment A, in the same manner as the embodiment A3-1, the integrator is constructed by using an inexpensive diffractive optical element in place of a pair of conventional expensive pair of fly-eye lenses to produce the integrator. The increase in cost can be significantly suppressed, the projection efficiency can be improved, the outer diameter of the reflector can be made smaller, and the image display device can be made thinner and lighter.

The diffraction optical element 301 may be provided between the lamp 102 and the dichroic mirror 317 or the like as described above, but the dichroic mirror 317 or the like between the image display element 314 and the like. You may install it.

As the reflector, an ellipsoidal mirror as in the following embodiments A3-3, a spherical mirror may be used, or a hologram element as in the embodiments A3-4 may be used as the diffractive optical element.

(Embodiment A3-3)

An example of an image display apparatus using an ellipsoidal mirror for the reflector will be described.

As shown in FIG. 30, this image display device is provided with an ellipsoidal mirror reflector 353 in place of the reflector 103, which is a water mirror, as compared with the image display device (FIG. 26) of Embodiment A3-1. And the diffraction optical element 351 and the projection lens 357 corresponding to the reflected light flux from the reflector 353 are provided instead of the diffraction optical element 301 and the projection lens 107. The other configurations and functions are the same. That is, when the light emitting region of the lamp 102 is arranged at the first focus of the reflector 353, which is an ellipsoidal mirror, the reflected light beam from the reflector 353 is usually focused at the second focus. Since the diffraction optical element 351 is provided on the path of the reflected light beam, the diameter of the region where the reflected light beam of the diffraction optical element 351 enters, that is, the region where the diffraction light beam exits, is determined by the outer diameter of the reflector 353. Smaller than the aperture diameter). Therefore, since the outer diameter of the diffraction optical element 351 can be made small, and the maximum incident angle of the diffraction light beam incident on the image display element 303 can be made small, the F value of the projection lens 357 is large. The manufacturing cost can be used cheaply.

Further, a plurality of diffraction regions are formed in the diffraction optical element 351, and the point or the manufacturing method of the output light fluxes of each diffraction region overlapping on the image display element is also the same as in the embodiment A3-1.

Also, the effects obtained by improving the projection efficiency, in particular, the effects obtained by improving the projection efficiency due to the improvement of the effective aperture ratio when using a micro lens as the image display element, can be obtained. Same as 1.

In addition, when the light emitting area of the lamp 102 is relatively large, the reflected light beam from the reflector 353 does not focus at one point, but many components are collected before and after the second focus, and on the image display element 303 A deviation (for example, diffraction image) occurs in the image of the overlapping light source. Therefore, when the condensation degree of the reflected light beam is bad, this shift is looked at from the beginning, and the diffraction light flux in each diffraction area is set so that the area illuminating the image display element 303 becomes small, and from the light beam condensed at the second focus. Other parts may be illuminated by the displaced luminous flux.

(Embodiment A3-4)

As an diffractive optical element, an example of an image display apparatus using a hologram element produced by two-beam interference exposure or CGH (Computer Generated Hologram) will be described.

As shown in FIG. 31, this image display apparatus is provided with a diffraction optical element 361 in place of the diffraction optical element 301 as compared with the image display apparatus (FIG. 26) of Embodiment A3-1. The point where the optical axis of the lamp 103 and the reflector 102 (the optical axis of the illumination optical system) is configured to have a predetermined angle with the optical axis (the optical axis of the projection optical system) such as the hologram element 361 and the projection lens 107 The other structure and operation are the same.

The hologram element 361 is set to be a phase hologram and set so that the reflected light beam from the reflector 103 is incident at an incident angle of 30 degrees, for example. This is to eliminate high order diffracted light and to increase the diffraction efficiency of the transmission hologram. Moreover, the external shape when the hologram element 361 is seen from the normal direction is formed in the ellipse which has a long axis in an x-axis direction as shown in FIG. This is because, as is generally the case, the output light flux from the reflector 103 is circular, and when the optical axis of the illumination optical system and the optical axis of the projection optical system are not parallel, the circular image projected on the hologram element 361 is shown in the figure. Because it is the same oval.

In the inner region of the hologram element 361, as in the hologram element 301 of Embodiment A3-1, a plurality of rectangular diffraction regions 361a are formed. The shape of each of the rectangular diffraction regions 361a is formed such that the image display area of the image display element 303 is similar to the shape in which the long axis: shortening ratio in the external shape of the hologram element 361 is enlarged in the longitudinal direction. FIG. 32 shows an example in which the image display element 303 is configured to display a so-called high-vision (HDTV) image having an aspect ratio of 16 (horizontal direction): 9 (vertical direction).

In addition, as described in Embodiment A3-1, the shape of the diffraction region 361a may not necessarily be a shape corresponding to the image display element 303, and may not be the same size or shape as each other. That is, the size, shape, and number of the diffraction areas 361a are not particularly limited, and the light quantity staining is generally provided when the luminous flux output from each diffraction area 361a is superimposed on the image display area of the image display element 363. The effect of reduction is obtained.

In addition, even in the case where 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 also be used.

Next, a manufacturing method of the hologram element 361 will be described.

The hologram element 361 can also be produced by recording the calculated interference height in a photoresist by electron beam writing or the like. However, the case where the hologram element 361 is produced by exposure to an interference height such as a photopolymer will be described.

Generally, a hologram element is produced by interfering two interfering beams (reference light and object light), and recording the generated interference height by exposure of a recording material such as a photopolymer. As the reference light, a light beam almost the same as the output light beam from the reflector may be used. For example, when using a spectacle mirror for the reflector 103 as described above, the parallel light may be incident at an angle parallel to the optical axis of the actual illumination optical system. As the object light, a light beam of an optical path incident on the entire display area of the image display element 303 in the region where each diffraction region 361a is to be formed and overlapping on the image display element 303 is used.

Hereinafter, it demonstrates concretely based on FIG. FIG. 33 is a layout view of an interference exposure system in the case where an interference height is recorded in one region 317a to form a diffraction region of the hologram material 371.

As the hologram material 371 for manufacturing the hologram element 361, various things as shown in the said embodiment A1-1 can be used.

The parallel light beam L output from the laser 372 is made to be two minutes into the transmitted light M and the reflected light N by the half mirror 373.

The transmitted light M is a region 371a of the hologram material 371 at a predetermined angle of incidence through an opening 375a provided corresponding to the region 371a of the hologram material 371 in the mirror 374 and the mask 375. ) Is incident as reference light. The predetermined angle of incidence is an angle equal to the angle formed between the optical axis of the reflector 103 (rotation axis of the rotating spectacle mirror) and the normal of the hologram element 361 in the image display device actually configured.

On the other hand, the reflected light N illuminates the same area as the display area of the image display element 373 through the auxiliary lens 372 after passing through the opening 375a of the mask 375 by the condensing lens 376. The light beam is converted into a light beam and incident on the area 371a of the hologram material 371 as object light.

By recording the interference height formed by the two light beams incident on the hologram material 371 as described above to the hologram material 371, one diffraction area is formed, and this is sequentially repeated for each diffraction area. The hologram element 361 as described above is manufactured.

Another method of manufacturing the hologram element 361 will be described.

In this method, the reference light is the same as in the above case, but the lens array 381 is used to generate the object light as shown in FIG. In this lens array 381, a lens 381a corresponding to each region 371a is formed so that a diffraction region of the hologram material 371 is formed. Each lens 381a is adapted to act in the same way as the condenser lens 376 of the above method for each area 371a of the hologram material 371.

Here, the hologram material 371 may be exposed to each area 371a by using the mask 375 in the same manner as described above, but by using the mask 382 as shown in FIG. 34. A plurality of areas 371a can be exposed at the same time. Each mask 381a of the lens array 381 and an opening 382a corresponding to each area 371a of the hologram material 371 are formed in the mask 382, and each lens of the hologram material 371 is formed. The areas where the object light passing through 381a is incident are usually formed so as not to overlap with each other, and the gaps do not open.

In addition, in the case of an image display apparatus using an ellipsoidal mirror as a reflector as an reflector as in the embodiment A3-5 described below, the reference light is focused as the reference light, instead of parallel luminous flux, at the second focusing point in the actual illumination optical system. A luminous flux equivalent to the luminous flux may be used. Such luminous flux can be easily obtained by arranging a lens having a predetermined refractive power in the optical path of the transmitted light M on the reflector's optical axis.

In addition, the diffraction regions 361a may be formed by generating the reference light or the object light by various methods as described in the above embodiments A1-1.

(Embodiment A3-5)

As shown in FIG. 35, the hologram element 391 may be used as the diffractive optical element, and the ellipsoidal mirror 353 may be used for the reflector.

That is, the hologram element 391 in which the diffraction region 391a is formed may be disposed on the path where the output light flux from the lamp 102 is collected at the second focal point by the reflector 353 composed of an ellipsoidal mirror. As a result, the diffracted light beams from the diffraction regions 391a of the hologram element 391 enter the image display element 303 through the auxiliary lens 302 (can be omitted). The output light flux of the image display element 303 is projected on the screen (not shown) by the projection lens 357.

The hologram element 391 can be manufactured by using, as the reference light, a light beam equivalent to the reflected light beam focused at the second focus from the reflector 353 as the reference light, as described in the above-described embodiment A3-4.

In the image display device as described above, the illumination incident on the image display element 303 is made such that the hologram element 391 can be arranged close to the second focal point and made small, similar to the image display apparatus of Embodiments A3-3. The effect of improving the projection efficiency by reducing the manufacturing cost by increasing the maximum incident angle of the light beam, increasing the gain of the microlens of the image display element 303, and the like is obtained.

(Embodiment A3-6)

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

As the reflective hologram element 401, for example, a so-called volume hologram is used. The hologram element 401 is arranged such that its normal line 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, but the diffraction region 401a is formed to be output from each diffraction region 401a. Light is superimposed on the image display element 303. Such a hologram element 401 can also be produced by the method described in the embodiments A1-1 and A3-3. As the reflector, an ellipsoidal mirror or spherical mirror may be used as in the embodiment A3-5.

(Embodiment A3-7)

A three-plate type image display apparatus for displaying a full color image using a hologram element as a diffraction optical element, a dichroic prism for color separation and color synthesis, and a transmission type display element as an image display element. Explain the example.

37, the dichroic prism 415 for color separation after the white output light beam of the lamp 102 is condensed by the reflector 103, reflected by the mirror 414, as shown in FIG. ), And separated into three primary colors of light flux. The light beams separated into various colors are incident on the reflective hologram elements 416 to 418 having a plurality of diffraction zones as in Embodiments A3-6, and the light beams diffracted in each diffraction zone are transmitted through the mirrors 419 to 421. They are superimposed on the image display elements 422 to 424 and are synthesized by the dichroic prism 425, and then enlarged and projected onto a screen (not shown) by the projection lens 107.

Also in the above image display apparatus, the effect of reducing the manufacturing cost and improving the projection efficiency is obtained.

In addition, each of the hologram elements 416 to 418 can realize higher efficiency by allowing the peak of the wavelength dispersion of the diffraction efficiency to be included in the wavelength band of the incident light beam. Specifically, what is necessary is just to use the thing of the wavelength of the light beam which injects, respectively, as a laser beam at the time of hologram preparation.

As the reflector, an ellipsoidal mirror, a spherical mirror, or the like may be used as well as the mirror surface mirror.

Instead of the hologram element, the relief type diffractive optical element shown in Embodiment A3-1 may be used.

(Embodiment A3-8)

An example of an image display apparatus different from the above-described embodiments A3-7 is described in that a reflective display element is used as the image display element.

38, the dichroic prism 415 for color separation after the white output light beam of the lamp 102 is collected by the reflector 103, reflected by the mirror 414, as shown in FIG. ), And separated into light beams of three primary colors. The light beams separated by each color are incident on the reflective hologram elements 416 to 418 in which a plurality of diffraction regions are formed as in Embodiment A3-6, and the light beams diffracted in each diffraction region are transmitted through the PBSs 431 to 433. Overlaid on the reflective image display elements 434 to 436 and luminance-modulated, and then synthesized by the dichroic prism 425 through the PBSs 431 to 433, and not illustrated by the projection lens 107. To be projected on a screen that is not

As the above-mentioned reflective image display elements 434 to 436, an electric recording type or an optical recording type liquid crystal panel or the like can be used in the polarization type image display element.

Even in this case, effects such as reduction in manufacturing cost and improvement in projection efficiency are the same.

(Embodiment A3-9)

An example of an image display apparatus further provided with a polarization conversion element in the configuration of Embodiments A3-2 (FIG. 28) will be described.

As shown in Fig. 39, the image display apparatus outputs the output light flux from the lamp 102 as a reflection beam that is substantially parallel by the reflector 103 of the mirror, for example, and is perpendicular to the surface of the drawing. The optical lens array 441 of the polarization conversion element 444 arranged in the long side direction is condensed in a splitter shape to form an elongated splitter shape near the focal point of the cylindrical lens 441. . The polarization splitting element 442 and the polarization plane rotating means 443 are arranged near the focal point, and the luminous flux whose polarization direction of the reflected luminous flux from the reflector 103 matches the specific direction is outputted. On the path of the output optical path, a diffraction optical element 301 is formed in which a plurality of diffraction regions are formed. Other configurations are the same as those of Embodiment A3-2 (FIG. 28).

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

By combining the diffraction optical element 301 and the polarization conversion element 444 having the function as an integrator as described above, a higher projection efficiency can be realized.

In addition, the same effect can be obtained even if the polarization conversion element is combined with the structure synthesize | combined with a dichroic mirror like Embodiment A3-2 (FIG. 29).

(Embodiment A3-10)

As shown in Fig. 40, the image display device of this embodiment A has the hologram element described in the above embodiments A1-1 and the like in the image display device having the diffraction optical element 301 as shown in the above embodiments A3-2. A reflective hologram element 399 having the same function as 105 is further provided. The rest of the configuration is the same as in Embodiment A3-2. As a result, even when the light emitting area of the lamp 102 has a certain size, or when any of a mirror mirror, an ellipsoid mirror, a spherical mirror, or the like is used as the reflector 103, the reflector is used by the hologram element 399. Since the reflected light beam from 103 is converted into parallel light beam or convergent light beam as in the case of using an ideal point light source and a desired reflector, high projection efficiency can be obtained, high projection efficiency can be obtained, and a diffraction optical element Since the luminous flux output from each diffraction region formed at 301 overlaps on the image display elements 314 to 316, light spot staining at the center and periphery of the display image can be reduced.

As the hologram element 399, a transmission type such as the embodiment A1-1 or the like may be used, or a reflection type may be used as the diffraction optical element 301.

In addition, as the liquid crystal display element, a reflective one may be used using the configuration and the like as shown in Fig. 15 and Fig. 24.

Further, the polarization conversion element or the like described in 108 of the embodiment A may be further provided so as to further increase the projection efficiency.

In each of the above examples, a liquid crystal panel is used as an image display element, but the liquid crystal panel is disclosed in, for example, Japanese Patent Application Laid-open No. H 1-281426, Japanese Patent Application Laid-Open No. 3-140920, and Japanese Patent Application Laid-Open No. 4 As disclosed in many publications No. 251221 and the like, an image display element having a function of increasing an effective aperture ratio by arranging one microlens in each pixel and converging the incident light beam near the opening of the pixel may be used. There is no restriction on the modulation material, the light modulation method, and the pixel driving method.

That is, optical materials having optical anisotropy, such as various liquid crystal materials such as vertically aligned liquid crystals (hereinafter referred to as VA liquid crystals) or optical crystals having electro-optical effects, including twisted nematic liquid crystals (hereinafter referred to as TN liquid crystals). It is also possible to use a polarization type image display element. In addition to the polarization type image display element, a scattering image display element which displays an image by scattering the incident light beam using a polymer dispersed liquid crystal (hereinafter referred to as PDLC) may be used.

Further, for example, as disclosed in Japanese Patent Application Laid-open No. Hei 7-284759, a diffractive image display element can also be used.

As the driving of the element, an image display element using not only TFT but also a thin film diode (hereinafter referred to as TFD) can be used. Further, as a material for forming driving elements such as TFT and TFD, high temperature polycrystalline silicon (hereinafter referred to as high temperature p-Si), low temperature polycrystalline silicon (hereinafter referred to as low temperature p-Si) and amorphous silicon (hereinafter, a Image display elements using " Si "

In the transmissive liquid crystal panel, for example, as disclosed in many Japanese Patent Application Laid-Open Nos. Hei 1-281426, Japanese Patent Application Laid-Open No. Hei 3-140920, etc. By converging the incident light flux in the vicinity of the opening of the pixel, one having a function of increasing the effective aperture ratio may be used, and there is no restriction on the light modulation material, the light modulation method, and the pixel driving method.

In other words, starting with a twisted nematic liquid crystal (hereinafter referred to as TN liquid crystal), various liquid crystal materials such as a vertically aligned liquid crystal (hereinafter referred to as VA liquid crystal), or optical crystals having an optical effect such as an electro-optic effect. A polarization type image display element using an optical material can also be used.

In addition to the polarization type image display element, a scattering image display element which displays an image by scattering the incident light beam using a polymer dispersed liquid crystal (hereinafter referred to as PDLC) may be used.

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

In addition, any of an active matrix method (hereinafter referred to as an AM method) for forming a drive element in each pixel, and a simple (passive) matrix method (hereinafter referred to as a PM method) for driving a device directly from a simple matrix electrode. The image display element of the driving method can also be used.

As the lamp, a metal halide lamp, a halogen lamp, a xenon lamp, an ultrahigh pressure mercury lamp, or the like can be used. Although the light emitting body is more preferable, in the present invention, there is no reason why the light emitting body must be particularly small. For example, a lamp having a large light emitting body such as a high output xenon lamp or a high output metal halide lamp may be used in advance.

As a reflector corresponding to the condensing means in the present invention, it is preferable to use an object mirror, an ellipsoidal mirror, or a spherical mirror. In this case, it is preferable to provide a light emitter of the lamp 2 in the vicinity of the focus, in the case of an ellipsoid mirror, in the vicinity of the first focal point, and in the case of a spherical mirror, in the vicinity of the center of the sphere.

In addition, although the dichroic mirrors 15 and 16 were used for a color synthesis system, you may comprise a color synthesis system using a dichroic prism. In addition, the output light beams from three liquid crystal panels may be projected using three projection lenses, respectively, without using a color synthesis system, and synthesized on a screen. It is also possible to use a dichroic prism for the color separation system.

In addition, when the image display element is a polarization type like a liquid crystal panel, in the illumination optical system of the present invention, the projection efficiency can be further improved by adding a polarization conversion element composed of polarization separation means and polarization plane rotating means. Done. As a polarization conversion device, for example, Japanese Patent Application Laid-Open No. 5-107505, Japanese Patent Application Laid-Open No. 6-202094, Japanese Patent Application Laid-Open No. 7-294906, Japanese Patent Application Laid-Open No. 8-234205, and Japanese Patent Publication As disclosed in Japanese Patent Application Laid-Open No. 9-105936 or the like, a so-called polarization conversion element composed of a combination of polarization separation means and polarization plane rotating means can be used. Even when either polarization conversion element is used, the configuration of the basic optical system and the manufacturing method of the hologram element described later do not change.

Moreover, you may make it combine the various structures shown in each Embodiment A. FIG.

Incidentally, the hologram element of the present invention and the image display apparatus using the hologram element can be modified in various ways based on the well-known aspect of the present invention and are not limited to the embodiment configured in Embodiment A.

Embodiment B1

An example of a hologram which is a diffraction optical element of polarization selectivity with different diffraction effects depending on the polarization direction of incident light will be described.

As shown in Fig. 10, the hologram element is, for example, an ultraviolet curable liquid crystal (hereinafter referred to as "between" two glass substrates 502 on which conductive transparent electrodes (hereinafter referred to as "ITO") are formed. UV cureable liquid crystal ”) and a region 503 including the molecule 503a and, for example, a region 504 including the non-polymerizable liquid crystal molecule 504a. The UV-curable liquid crystal is a photocurable liquid crystal having refractive index anisotropy cured by a light beam having a specific wavelength. On the other hand, a nonpolymerizable liquid crystal is a liquid crystal material which does not harden | cure with respect to the light flux of the wavelength which hardens the said UV curable liquid crystal.

Here, the expression regarding "optical anisotropy" is demonstrated. As shown in general liquid crystal materials or uniaxial optical crystals, in the optical material having refractive index anisotropy, the refractive index with respect to the normal light and the refractive index with respect to the abnormal light can be defined. The normal light is polarized light in which the refractive index does not depend on the incident angle of the light beam, and the abnormal light is polarized light in which the refractive index differs depending on the incident angle. The refractive index according to the incident angle with respect to the abnormal light is obtained by the so-called refractive index ellipsoid (see, for example, Kudou, Uehara, `` Basic Optics '', Modern Engineers, p. 202) shown in FIG. Can be. By the way, when the optical anisotropy with respect to the incident luminous flux in each region is not particularly periodic, it is abbreviated simply as "optical anisotropy in each region", and the meaning is the "image light with respect to the incident luminous flux in each region." Anisotropy of refractive index with respect to abnormal light ”. In addition, "the optical anisotropy of the area | region 503 and the area | region 504 is almost the same" means that the refractive index with respect to the incident light beam and the refractive index with respect to the abnormal light beam are almost the same in both areas, respectively. " Shall be. Similarly, "the optical anisotropy of the regions 503 and 504 is different" means that "the refractive indices of incident light rays are almost the same in both regions, but the refractive indices of the abnormal rays are different in both regions". I mean it. In addition, the term "optical anisotropy" and "index anisotropy" are used by the same meaning.

As shown in FIG. 10 (a), when the hologram element has no voltage applied between the ITOs 501, the liquid crystal molecules 503a and 504a are substantially the same as the regions 503 and 504. Orientation in the direction (direction substantially parallel to the glass substrate 502) and the optical anisotropy of the area | region 503 (after hardening) and the area | region 504 are made to be substantially the same. That is, in the regions 503 and 504, the refractive index with respect to the normal light is almost the same (the value is no), and the refractive index with respect to the abnormal light is also almost the same (the value is ne). On the other hand, when a predetermined voltage is applied between the ITOs 501, as shown in FIG. 10B, only the liquid crystal molecules 504a of the region 504 are oriented (switched) in the direction of the electric field line, and the region 503 ) And region 504 have different optical anisotropy.

The hologram element constructed as described above functions as a hologram element with respect to P-polarized light (ideal light) by applying a voltage between the ITOs 501, and the incident light beams have the pitch and the film thickness of the regions 503 and 504. Diffraction in the direction according to. That is, only P-polarized light is diffracted selectively, and S-polarized light (normal light) goes straight (FIG. 10B). Thus, the selective diffraction of only the P-polarized light is the same even when the light beam is incident on the hologram element in an oblique direction. On the other hand, in a state where no voltage is applied, both P and S polarized light go straight (FIG. 10A). In this hologram element, even when no voltage is applied, both P and S polarized light can reliably go straight even when incident in an oblique direction. That is, as shown in FIG. 11, when the light beam is incident in an oblique direction, not only the refractive index with respect to the normal light is equal to no in the regions 503, 504, but also the refractive index for the abnormal light is also in the regions 503, 504. Since it becomes equal to ne (θ), not only normal light but also abnormal light can be straightened without diffraction.

In this manner, according to the hologram element, both the normal light beam and the abnormal light beam can be reliably straightened, or only the abnormal light beam can be selectively diffracted even with respect to the light beam incident in the oblique direction.

Next, the manufacturing method of the above-mentioned hologram element is demonstrated. This hologram element can be formed by so-called mineral organic phase separation by, for example, irradiating an interference height of two light beams.

(1) First, an alignment film (not shown) is applied to two glass substrates 502 on which the ITO 501 is formed, and an alignment treatment is performed.

(2) For example, by dispersing beads (not shown) having a predetermined diameter, a cell gap is secured and two glass substrates 502 are bonded together (silicon oxide or photopolymer instead of bead dispersion). You may form the pillar of predetermined height etc.).

(3) For example, a liquid crystal material obtained by mixing a non-polymerizable liquid crystal and a UV cureable liquid crystal in a weight ratio of 1: 1 is injected and sealed.

(4) Two-beam interference exposure irradiates the interference pitch of the desired pitch to cure the UV-curable liquid crystals of the strongly irradiated portion and harden most of the UV-curable liquid crystal molecules in the mixed liquid crystal by the mineral organic phase separation phenomenon. Gathered negatively, good area separation is performed.

Here, in the process of (4), when the voltage is applied between the ITOs 501, the two-beam interference exposure is performed on the liquid crystal molecules, for example, in a liquid crystal oriented almost perpendicular to the glass substrate 501. As shown in Fig. 12, when the voltage is applied, the optical anisotropy becomes almost the same, so that both the P-polarized light and the S-polarized light at the incident light beam go straight, while when the voltage is not applied, the optical anisotropy of each area is different, and only the P-polarized light The inverted mode hologram element in which this diffraction and S-polarized light go straight can be manufactured.

In addition, as an element driving method, it is generally preferable to apply an AC voltage. However, when a ferroelectric liquid crystal is used as the non-polymerizable liquid crystal, for example, a pulse-like voltage may be applied by utilizing the memory property. .

Here, the difference between the hologram element of the present invention and the conventional hologram element will be described. For example, the operation principle is basically the same as that of the conventional example 1, but the conventional example 1 merely uses a photocurable polymer material in the region 503, and does not disclose any refractive index anisotropy. not. On the other hand, the hologram element of the present invention is characterized in that the photocurable liquid crystal has refractive index anisotropy, and ne and no after the curing are the same as the nonpolymerizable liquid crystal in the region 504, and therefore the incident angle characteristic can be improved. For example, consider a light beam that is incident vertically (see FIG. 2 (a)).

In the conventional example 1, since the region 503 made of the photocurable polymer material does not have refractive index anisotropy, the refractive index is always the value n1 which is almost equal to the no of the liquid crystal. In Conventional Example 1, the liquid crystal molecules are controlled to have a configuration as shown in Fig. 8A, so that the incident light beam 3 can go straight without diffraction.

However, as shown to Fig.9 (a), although the normal light beam (S polarization light 5 in this case) can go straight with respect to the oblique light beam 3 ', in this case, the abnormal light beam (P in this case) This is because the polarized light 4 is diffracted because the refractive index of the region 504 becomes ne (θ), while the region 503 remains the refractive index no. As shown in Fig. 9B, the refractive index with respect to the abnormal light can be determined by the refractive index ellipsoid.

The said phenomenon was a subject common to all the conventional elements in which the polymeric material to harden does not have refractive index anisotropy essentially, as disclosed, for example in Conventional Example 2-Conventional Example 6, etc.

In addition, although the conventional example 6 is not a hologram element, there is no description regarding the refractive index between a photocurable polymer material and a nonpolymerizable liquid crystal, and in this case, a slight occurrence occurs when the polymer material is formed in a narrow gap cell. Refractive index anisotropy becomes a problem.

(Embodiment B2-1)

An example of a polarization splitting element constructed using a hologram element will be described. This polarization splitting device separates the incident light beam into S, P polarized light and emits them at slightly different emission angles. For example, a polarization converting device or the like is used to obtain a light beam matching the polarization direction. do.

As shown in Fig. 13, the polarization splitting element 501 is configured by joining the first hologram element 511 and the second hologram element 512 together. Luminous flux substantially parallel to the normal direction (Z-axis direction in the drawing) of the first hologram element 511 ( ) Is incident, for example, the S-polarized component (polarization component having a polarization plane parallel to the X-axis shown in the figure) is diffracted, for example, with an emission angle of 45 ° (substrate normal, i.e., Z-axis, An angle formed by the Z-axis and the advancing direction of the incident light), and is incident on the second hologram element 512 at an incident angle of 45 °. On the other hand, the P polarization component (polarization component having a polarization plane parallel to the Y axis) is allowed to pass through the first hologram element 511 as it is.

The S-polarized light incident on the second hologram element 512 at the incident angle of 45 ° is diffracted by the second hologram element 512 and is emitted at an exit angle of, for example, -7 °, while P The polarized light is transmitted in parallel with the Z axis like the first hologram element 511. That is, in this polarization splitting element 510, it is possible to 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 511 and 512, for example, the hologram elements of the above embodiment B1 can be used. In this case, the above operation can be performed by applying a predetermined voltage to the ITO of each hologram element. . In addition, you may use the hologram element which makes the above-mentioned diffraction, respectively, without applying a voltage. Such a hologram element can be produced as follows, for example.

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

(2) An orientation film (not shown) is applied onto each conductive transparent electrode and subjected to a rubbing treatment.

(3) Sphere beads (not shown) having a desired diameter are dispersed on the conductive transparent electrode.

(4) A seal material (not shown) is applied to the periphery of the glass substrate 513.

(5) The glass substrates 513 and 514 are bonded together to harden the material by heat treatment.

(6) In the injection port (not shown), for example, UV curable liquid crystal 515 is injected as a hologram material.

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

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

In addition, the manufacturing method of such a cell is a well-known technique in the field of optics, and a two-beam interferometric optical system also divides a coherent laser beam into two, and irradiates at a predetermined angle to a predetermined direction and pitch. It is a known technique for forming an interference height of.

Next, the principle in which the hologram element having polarization selectivity is formed by the above production method will be described. UV-curable liquid crystals are liquid crystals that are cured by irradiating UV light, for example, light having a wavelength around 360 nanometers. The molecules 515a of this liquid crystal are usually oriented in the rubbing direction as schematically shown in FIG. 14 in the state before the UV exposure of (7) after the injection of (6) by the rubbing treatment of (2). .

In this state, when the interference height formed by the two-beam interference optical system is irradiated to the UV-curable liquid crystal 515 as described below, the UV-curable liquid crystal 515 cures according to the light intensity of the interference height. Specifically, for example, as shown schematically in FIG. 15, when an interference height having a light intensity distribution is formed in the Y-axis direction of the same figure, only the liquid crystal molecules 515b of the strongest portion are cured.

Subsequently, when a voltage is applied between the conductive transparent electrodes, as shown in Fig. 16, only the liquid crystal molecules 515a in the portion where the light intensity of the interference height is weak are oriented (switched) in the direction of the electric line of force. When the UV light is irradiated to the whole surface in this state again, even if voltage application is stopped, it becomes a hologram element in which the arrangement state of the liquid crystal molecules was maintained as shown in FIG. That is, the area | region which the liquid crystal switches and the area | region which is not switching are formed by the small pitch of interference height. Therefore, since the liquid crystal molecules optically have uniaxial refractive index anisotropy, in the example of FIG. 16, the polarization component oscillating in the Y-axis direction, whereas the polarization component oscillating in the X-axis direction, acts as a phase diffraction element. The component functions as a diffractive element having polarization anisotropy that is output as an isotropic element without diffraction.

In Embodiment B, specifically, the hologram elements 511 and 512 are manufactured with the following parameters.

Tilt angle of interference height of the first hologram element: 22.5 °

Pitch of the interference height of the first hologram element: 0.757 µm

Thickness of the first hologram element: 9 μm

Tilt angle of the interference height of the second hologram element: 19 °

Pitch of the interference height of the second hologram element: 0.651 µm

Thickness of the second hologram element: 9 μm

Average refractive index of the liquid crystal: 1.593

Refractive Index Change: 0.083

17 shows the diffraction efficiency of the S-polarized light of the polarization splitting element 510 manufactured as described above. The horizontal axis is the angle of incidence of the first hologram element 511. As shown in the drawing, high polarization separation characteristics of 90 ° or more in a range of ± 2 ° can be realized.

In addition, in the case of using a UV-curable liquid crystal which can be oriented in a magnetic field as the liquid crystal material, it is not necessary to form a conductive transparent electrode on the surfaces of the glass substrates 513 and 514. Instead, a magnetic field can be applied.

In addition, as the hologram material 27, a mixture of a photopolymer having a sensitivity to a specific wavelength region and a liquid crystal polymer may be used to fabricate the hologram element by optical organic phase separation.

In this embodiment B, although the optical axis defined as the normal of the glass substrates 513 and 514 and the incident light beam generally coincide, they do not necessarily need to coincide.

As the hologram element used for the above-mentioned polarization splitting element, what is shown, for example in FIG. 18 can also be used. The hologram element 512 is formed using an optical medium 522 having refractive index anisotropy such as, for example, liquid crystal, and because the thickness is about 10 µm, the refractive index distribution is also periodically distributed in the thickness direction. . For this reason, the diffraction effect varies depending on the polarization direction, and the diffraction effect has a characteristic of showing high diffraction efficiency in one direction.

Hereinafter, the hologram element 521 will be described in detail.

The device has a layer structure in which a layer inclined with respect to the thickness direction is periodically formed on the surface where light is incident. In the layers adjacent to each other, one side is arranged such that the inclination of the optical axis of the optical medium 522 having refractive index anisotropy is parallel to the surface of the hologram element 521, and the other side is arranged perpendicular to the surface.

When light enters the optical medium 522 having the refractive index anisotropy, when the polarization direction of the light is parallel to the optical axis of the optical medium 522, the light becomes abnormal light. Therefore, the refractive index represents Ne. In addition, when the polarization direction is perpendicular to the optical axis of the optical medium 522, the light becomes normal light and exhibits a refractive index of No. Where Ne> No.

Next, in the hologram element 512 shown in FIG. 18, the light which has a polarization direction perpendicular to the ground is made into the normal light, the light which has a polarization direction parallel to the ground is made into the ideal light source, and these light The operation at the time of entering the hologram element 521 will be described.

First, when an image ray enters, the polarization direction becomes perpendicular to the optical axis of any optical medium 522 constituting each layer. For this reason, the refractive index in each layer becomes No regardless of the direction of the optical axis between each layer. As a result, since an even medium having a refractive index of No exists, the image light incident on the light is transmitted as it is, without being affected by diffraction.

On the other hand, when the abnormal light is incident, in the layer in which the optical axes of the optical medium 522 having refractive index anisotropy are arranged in parallel with the incident surface, the polarization direction of the incident light becomes parallel to the optical axis. For this reason, it corresponds to the case where it passes through the layer which has the refractive index of Ne. Further, since the polarization direction is perpendicular to the optical axis for the layer in which the optical axis of the optical medium is perpendicular to the incidence plane of the hologram element 521, this layer acts as having a refractive index of No. Thus, the hologram element 521 passes through a plurality of layers having different refractive indices periodically in the thickness direction, which is the traveling direction of the incident light, with respect to the abnormal light beam. As a result, the incident light is subjected to the so-called black diffraction, in which light is focused in a specific direction corresponding to the inclination angle of the layer and the pitch of the period. Therefore, as shown in the figure, the abnormal light passes through the hologram element 521 and changes the optical path with respect to the layer structure formed inside the element.

In other words, the black diffraction condition is applied to the structure having a periodic structure in the thickness direction as described above. This is because when light having a certain wavelength enters each layer forming a periodic structure, the light scattered in each layer causes the scattering components to become strong in a specific direction corresponding to the wavelength, the incident angle, and the pitch between the layers. do. This is called the black diffraction condition, and this condition has a three-dimensional configuration for a conventional two-dimensional diffractive optical element, and has a function of framing (converging light in one direction).

Therefore, compared with the conventional diffractive optical element, the diffraction effect can be remarkably improved, and the efficiency of 100% is logically possible. In fact, even if we consider loss on the way, we can expect more than 90% efficiency. On the other hand, in the binary two-dimensional diffraction optical element, since the diffraction wave includes the 0th order and is diffracted to the higher order in right and left symmetry, the diffraction efficiency in the first direction is about 40% at maximum, and passes through the device. As a ratio with respect to the total light quantity, it becomes a low value.

Fig. 19 analyzes the calculation result of the logical diffraction efficiency of the hologram element 521 as "Bell system technology J" (H. Kogelnik, (Bell Syst. Tech. J., 48, 1969, pp. 2909-2947)). It shows based on. The diffraction efficiency is the ratio of the amount of light diffracted in the first direction with respect to the total incident light amount. Table 1 shows various parameters of the diffractive optical element.

In Fig. 19, (a) is the change in diffraction efficiency when the incident angle is shifted from the black angle, that is, the angle of incidence of the diffraction efficiency, and (b) is the change in case the incident wavelength is shifted from the design value, that is, the incident wavelength of the diffraction efficiency. It shows the dependencies.

The angle dependency of FIG. 19A corresponds to the efficiency in the case where the luminous flux incident on the hologram element 521 is shifted from the parallel light (the incidence angle is shifted from a predetermined angle), and also in FIG. 19B. Incident wavelength dependence corresponds to examination of the efficiency etc. at the time of illumination by a white light source. As shown in the figure, by setting various parameters appropriately, it is expected that a theoretical diffraction efficiency of 1, and eventually high diffraction efficiency of near 100% can be obtained. According to the same figure, the wavelength is flat to around ± 100 nm in terms of wavelength, and high efficiency can be expected for white light.

In Fig. 18, the optical axis of the optical medium 522 constituting the hologram element 521 is inclined at an angle of 90 DEG between adjacent layers to show the case where the refractive index difference is the largest. It is also possible to set from Ne to an intermediate value of No. It is also possible to adjust the diffraction efficiency by selecting the refractive index distribution using the same.

It is also possible to divide the area of the hologram element 521 into several and shift the diffraction directions.

In addition, a layer having a different periodic structure, angle, etc. is formed corresponding to each of the central wavelengths of R: red (0.65 μm), G: green (0.55 μm), and B: blue (0.45 μm) constituting white light. By laminating these to form the hologram element 521 or by superimposing these structures on the hologram element 521, a configuration that mitigates the influence of wavelength dispersion or angle dependency can also be possible.

Next, the manufacturing method of the hologram element 521 is demonstrated.

First, for example, ITO is formed as a transparent conductive electrode on each pair of glass substrates.

Next, after removing the dust adhering to these substrates, an alignment film made of a polymer, for example, polyimide, is applied by spin coating or the like, and subjected to heat treatment. Form.

Thereafter, after the rubbing treatment in a specific direction is applied to the alignment film by a roller or the like, the yarn is printed around one substrate, and beads of about 5 µm to 20 µm in diameter are dispersed on the other substrate. The two substrates are bonded together so that their rubbing directions are paired with each other to form an empty cell.

As the optical medium 522 having refractive index anisotropy, the liquid crystal having positive dielectric anisotropy is injected into the empty cell. It is also possible to use liquid crystals having negative dielectric anisotropy. More specifically, the liquid crystal includes, for example, a photopolymerizable liquid crystal monomer or a photocrosslinkable liquid crystal polymer, and the liquid crystal is cured by light irradiation of a wavelength in the ultraviolet region around 360 nm and the direction of the liquid crystal molecules is immobilized. Use the one that has the characteristic. Although the said injection may be performed in air | atmosphere at room temperature, you may make it inject | pour in high temperature, about 40 degreeC-about 60 degreeC, and vacuum.

The liquid crystal sample is completed by sealing the injection port and the vicinity of the degassing part with the sealing agent with respect to the cell after inject | pouring a liquid crystal.

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

First, close the shutter for adjusting the exposure time and arrange the liquid crystal sample at a manufacturing position (predetermined position of the exposure apparatus) of the optical system in the absence of light irradiation, and open the shutter for a predetermined time, for example, for about one minute. After that, the exposure is performed by the interference height as the first exposure step by closing.

As the light source for forming the interference height, for example, laser light having a wavelength of about 360 nm output from an Ar (argon) laser having an irradiation intensity of about 50 Hz to about 100 Hz can be used. The laser beam is expanded into a beam of, for example, 30 mm to 50 mm by a beam expander or the like, divided into two directions by a beam splitter or the like, and an interference height is formed through an optical path set by combining mirrors and the like, and the liquid crystal Investigate the sample. This interference height is adjusted to, for example, about 1 [mu] m pitch at the position where the liquid crystal sample is arranged by adjusting the mirror or the like.

Upon exposure, the liquid crystal in the region belonging to the portion of the high light intensity in the interference height formed by the interference of the two light beams of the laser is cured, and the molecular axis is fixed in the direction in which the liquid crystal molecules are initially oriented by the alignment film. do. That is, for example, in the case of using a liquid crystal having positive dielectric anisotropy as described above, the liquid crystal molecules are initially evenly aligned in a direction parallel to the glass substrate. Will be preserved. On the other hand, in the region where the interference height is dark, the light intensity is lower than that of the light, so that the liquid crystal molecules hardly harden in this first exposure step.

Next, as a second exposure step, an alternating electric field of about 5 (V / µm) is first applied between ITO electrodes serving as transparent conductive electrodes formed inside the two glass substrates of the liquid crystal sample. By applying this electric field, the uncured liquid crystal molecules in the region which was the dark part of the interference height are inclined in the direction standing perpendicular to the glass substrate. Since the angle of inclination at this time is proportional to the electric field to be applied, it is possible to give a desired angle of inclination, and thus a difference in refractive index, by adjusting the magnitude of the electric field.

In the state where the voltage is applied as described above, by blocking one of the laser beams split by a beam splitter, for example, the front of the liquid crystal sample is irradiated with light of an even intensity distribution in which no interference height is formed, for example, for about 5 minutes. And the whole area | region which was the said unhardened dark part is hardened completely.

The hologram element 521 having a structure as shown in Fig. 18 is produced by performing the first exposure step and the second exposure step as described above.

In this case, a cell is fabricated using a glass substrate on which a transparent electrode such as ITO is formed, and the direction of the liquid crystal molecules is changed at an initial position by applying an electric field in the second exposure step. As another method, the hologram element 521 can be fabricated by performing a second exposure step by changing the direction of the liquid crystal molecules by applying a magnetic field without using a transparent electrode.

Moreover, the method of exposing by setting the polarization direction of the Ar laser beam to irradiate so that it may differ, for example by 90 degrees in a 1st exposure process and a 2nd exposure process is also considered. When linearly polarized light is irradiated on a polymer film such as an alignment film as a light source, molecules whose main chain (or side chain) is directed in the polarization direction mainly absorb the light and photoreaction among randomly oriented polymers. And optical anisotropy is expressed on the film. In the polymer material, the photoreaction process (photoisomerization, photopolymerization, photolysis) 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 of the ultraviolet region constituting the interference height, it is also possible to set the initial alignment state of the liquid crystal and to move the liquid crystal molecules in the first and second exposure steps.

The diffraction rate of the device fabricated as described above was measured by using a He-Ne laser to change the incident polarization direction. As a result, the transmittance to the normal light is around 98%, and has a high transmittance. Moreover, the diffraction efficiency in the primary direction with respect to the abnormal light beam is also about 90%, and a good result is obtained. Therefore, it was confirmed that the diffraction optical element manufactured here has high polarization separation characteristics and diffraction efficiency.

In addition, as an optical medium having refractive anisotropy, it is also possible to use uniaxial crystals having electro-optic effects such as lithium niobate, KD ₂ PO ₄ , β-BaB ₂ O ₄ , and PLZT in addition to liquid crystals. Similar effects can be obtained by using a medium having various refractive index anisotropies, including biaxial optical crystals such as KTiPO ₄ and the like.

(Embodiment B2-2)

Another example of a polarization splitting element constructed using a hologram element will be described.

As shown in Fig. 20, the polarization splitting element 503 is provided with a hologram element 532 as shown in the above-described embodiment B1 or B2-1 on the surface of the total reflection mirror 531. Here, when the hologram element of Embodiment B1 is used, it is used in the state in which the predetermined voltage was applied between ITO.

The total reflection mirror 531 and the hologram element 532 are arranged such that a normal line forms an angle of 45 ° with respect to an optical axis of the reflector 634 that reflects light from the lamp 533 of the light source.

In this hologram element 532, light having a polarization direction (called S polarization light) in a direction perpendicular to the surface of the drawing becomes an ordinary light beam, and light having a polarization direction in a direction parallel to the ground (P polarization light). Light) is arranged to be an abnormal light beam. In addition, the hologram element 532 is set to diffract the extraneous light incident at the incident angle of 45 degrees so as to be diffracted so as to have an emission angle slightly larger than 45 degrees.

With this configuration, the S-polarized light, which is an ordinary light beam with respect to the hologram element 532, is isotropically uniform without being affected by the refractive index distribution formed of the periodic structure of the element, as described in the above-described respective embodiments B. It exhibits the same characteristics as when passing through a medium of refractive index. Therefore, the S-polarized light is transmitted through the hologram element 532 as it is, reflected by the total reflection mirror 531, and again transmitted through the hologram element 532 and exits. In other words, the S-polarized light is bent by 90 ° by the total reflection mirror 531 and is emitted.

On the other hand, the P-polarized light that is the abnormal light with respect to the hologram element 532 is modulated and diffracted by the refractive index distribution of the periodic structure formed in the hologram element 532 and is emitted at an emission angle slightly larger than 45 ° as described above.

Therefore, the light emitted from the lamp 533 through the reflector 534 can be separated into the outgoing light having a slightly different propagation direction into the S-polarized light and the P-polarized light by the polarization splitting element 530.

(Embodiment B3-1)

An example of a polarization conversion element constructed using the polarization separation element of the above embodiment B2-2 will be described. The polarization conversion element outputs light in which the polarization direction from the light source is random in accordance with the polarization light in a predetermined direction, and is used for, for example, a polarization illuminator such as a polarization type liquid crystal display element.

21 is an explanatory diagram showing a configuration of a polarization illuminating device including a polarization converting 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 light, an inorganic or an organic EL element, or the like is used. The light from the lamp 533 is made into substantially parallel light by the reflector 534 and exits. This substantially parallel light is incident on the polarization splitting element 530, and as described in the embodiment B2-2, the advancing direction is slightly different from the S polarized light and the P polarized light and exits from the polarization splitting element 530.

S-polarized light and P-polarized light emitted from the polarization splitting element 530 enter the respective lenses 542a of the first lens group (the first fly-eye lens) 542 constituting the integrator 541, respectively. And condensed in different predetermined areas in each lens 543a of the second lens group (second fly's eye lens) 543 which is paired with each lens 542a according to each incident angle.

The predetermined region where the S-polarized light and the P-polarized light are collected is set to, for example, a region that divides each lens 543a into two parts, and at the same time, each of the lenses 543a in the region where the P-polarized light is focused. On the back side (light traveling direction side), a retardation plate 544, which is a half wave plate, is periodically provided. Thus, the S-polarized light incident on the second lens group 543 is emitted as S-polarized light as it is, while the P-polarized light is rotated by 90 ° through the phase difference plate 544, and converted into S-polarized light. Exit. That is, any polarized light is emitted in accordance with the S-polarized light.

This S-polarized light is incident on the image display element (light valve) 547 as a generally luminous flux through the field lens 545 and the condenser lens 546, and is used for image display.

When the hologram element 532 and the phase difference plate 544 are used as described above or not, the amount of light incident on the image display element 547 is compared. As a result, the hologram element 532 and the phase difference plate 544 are compared. In the case of performing polarization conversion, it was confirmed that the light utilization efficiency was improved by 1.2 to 1.6 times, and the function of the polarization conversion element 540 using the hologram element 532 was excellent.

(Embodiment B3-2)

An example of the polarization converting element in which the polarization splitting element described in the above embodiment B3-1 is provided in the optical path between the first lens group and the second lens group constituting the integrator to match the polarization direction is described. In addition, in Embodiment B etc., the same code | symbol is attached | subjected about the component which has a function similar to the said Embodiment B3-1, etc., and detailed description is abbreviate | omitted.

FIG. 22 is an explanatory diagram showing a configuration of a polarization lighting apparatus including a polarization converting element 545.

Parallel light from the reflector 534 is made to enter the polarization splitting element 530 through the first lens group 542 constituting the integrator 541. The light beams incident on the polarization splitting element 530 are emitted from the polarization splitting element 530 after being slightly different in the advancing direction from the S polarized light and the P polarized light as described in Embodiment B2-2.

The S-polarized light and the P-polarized light emitted from the polarization splitting element 530 are the back surface of each lens 543a of the second lens group (second fly's eye lens) 543 constituting the integrator 541, respectively. The light is condensed in the region where the retardation plate 544 is provided or in the region where the phase difference plate 544 is not provided. Thus, as in the above embodiment B3-1, the S-polarized light is emitted as S-polarized light as it is, while the P-polarized light is rotated by 90 ° through the phase difference plate 544, and is converted into S-polarized light and emitted. do. That is, any polarized light is emitted in accordance with the S-polarized light.

The polarization conversion element 545 configured as described above can also improve light utilization efficiency as in the embodiment B3-1.

(Embodiment B3-3)

An example of another polarization conversion element in which a hologram element as shown in the above embodiment B1 or embodiment B2-1 is used will be described.

FIG. 23 is an explanatory diagram showing a configuration of a polarization lighting apparatus including a polarization converting element 550. The polarization converting element 550 of this polarization illumination device is a phase difference plate 551 which is a quarter wave plate between the hologram element 551 and the total reflection mirror 531 as shown in the above embodiment B1 or embodiment B2-1. ) Is installed and configured.

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 in accordance with the refractive index distribution of the diffractive optical element or the like as described in Embodiment B1 and the like. The path is exited by bending in the direction indicated by the dashed-dotted line in the figure.

On the other hand, the S-polarized light is transmitted through the hologram element 551 as it is, reflected by the total reflection mirror 531 through the phase difference plate 552, the polarization direction in the process of passing through the phase plate 552 again compared to when the incident It changes by 90 degrees and 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 534, but this is a condition that is shifted from the diffraction conditions of the black with respect to the periodic structure formed inside the hologram element 551, so that the hologram element ( 551 transmits the incident light without reflecting it. That is, as described with respect to the angle dependence of the diffraction efficiency in FIG. 19A, when the incident angle to the hologram element is shifted to some extent from the predetermined angle, the efficiency becomes almost zero, and the diffraction does not occur, but only transmission. In some cases, the predetermined angle can be set according to the formation 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 can be transmitted through the hologram element 551 without diffraction. It is also possible to diffract and generally coincide with the propagation direction of the P-polarized light directly diffracted by the hologram element 551.

As described above, the P-polarized light is diffracted by the hologram element 551 by the light wave from the lamp 533, and the S-polarized light transmitted through the hologram element 551 is the front mirror 531 and the retardation plate 552. By converting the light into P-polarized light, the light is transmitted through the hologram element 551 and emitted, whereby a substantially parallel light beam having the same polarization direction can be obtained.

The light utilization efficiency of the polarizing light device was determined in the same manner as in the embodiment B3-1, and the light utilization efficiency was about 1.2 to 1.5 times as compared with the case where the hologram element 551 and the retarder 552 were not used. Can be obtained.

In addition, according to the above structure, since the polarization conversion can be performed only by a simple laminated structure of the hologram element, the retardation plate 552 and the total reflection mirror 531, the combination with an optical system such as an integrator is also easy, It can be used in a wide range of optical systems. In particular, when applied to a device having a pre-folded mirror, such as a color image display device having two dichroic prisms for color separation and color synthesis, the hologram element is provided in place of the mirror. Since only a mirror is used, the light utilization efficiency can be improved without causing an increase in the number of parts.

(Embodiment B3-4)

An example of another polarization conversion element in which a hologram element as shown in the above embodiment B1 or embodiment B2-1 is used will be described.

Using two hologram elements 561 and 562 as shown in the above embodiment B1 or embodiment B2-1, a polarization illumination device including the polarization conversion element 560 as shown in FIG. 24 was constructed.

The light beam including the P-polarized light and the S-polarized light from the lamp 533 enters the hologram element 561 through the reflector 534, and the S-polarized light is transmitted as almost parallel light as it is. In addition, the P-polarized light is diffracted by the hologram element 562 so that the propagation direction is generally changed by 90 degrees according to the principle described in Embodiment B1 and the like.

This light wave also enters the hologram element 562, where it is diffracted equally and exits so that the propagation direction is generally the same as the direction of the light beam reflected by the initial reflector 534. Thereafter, the light is transmitted through a retardation plate 563 which is a 1/2 wavelength plate, and the polarization direction is diffracted by 90 degrees to emit as S-polarized light. In other words, the light waves emitted from the lamp 533 and diffracted by the hologram element 563 are made by the diffraction light diffusing element 562 and the retardation plate 563 so that the light waves transmitted through the hologram element 561 coincide with the polarization direction. It emits as a parallel beam.

The reuse rate of the light waves in the hologram element 562 of the polarization lighting device as described above was measured. As the light beam from the hologram element 562, the intensity ratio of the light beam from the hologram element 561 is approximately 90%. The light beam converted into S-polarized light is obtained.

An advantage of using the hologram elements 561 and 562 as described above is that the separation angle in the case of performing polarization separation can be arbitrarily set. That is, in the case where polarization separation is performed by combining the polarizing beam splitter and the total reflection mirror as usual, in order to bend the propagation direction by 90 °, it is necessary to tilt the reflecting surface at 45 ° to the incident light (equivalent to θ in FIG. 24). ). Therefore, the size corresponding to the size and inclination of the reflecting surface is required in the inner direction, and the constraints in the thickness direction in the apparatus using the polarization illuminating device become large.

On the other hand, when the hologram element is used as described above, since the polarization separation angle can be arbitrarily set by the refractive index distribution formed therein, the diffractive optical element is inclined at 45 degrees or less with respect to the plane perpendicular to the incident light. 24 can be set at a small angle of 45 degrees or less, and the polarization conversion optical system can be configured by arranging the hologram elements in parallel in parallel to each other. Can be greatly reduced. For this reason, a thin structure can be attained and a compact system (lighting device, image display device, etc.) can be realized by combination with an illumination optical system such as an integrator in which polarized light with polarized light is incident.

(Embodiment B3-5)

An example of a polarization conversion element in which the hologram element as shown in the above embodiment B1 or embodiment B2-1 is used and coincides the polarization direction of the light output from the integrator having the first lens group and the second lens group will be described. .

A pair of hologram elements 571 and 572 as shown in the above embodiment B1 or embodiment B2-1 are paired, and as shown in FIG. 25, a plurality of sets are arranged and a polarization illuminating device including a polarization converting element 570 is constituted. did. In addition, the same figure shows an example in which the projection type image display apparatus is constructed by combining the image display element 577, the projection lens 578, and the like.

The light waves including the P-polarized light and the S-polarized light transmitted from the first lens group (not shown) in the integrator are incident on the second lens group 571 to bind the light beams, and each lens of the second lens group 571 ( It enters into the hologram element 572 corresponding to 571a. Here, the S-polarized light is transmitted as it is, and the P-polarized light is diffracted to enter the adjacent hologram element 572.

Further, it is further diffracted here, propagates in the same direction as the previous S-polarized light, and the polarization direction is rotated 90 degrees by the phase difference plate 574, which is a half-wave plate, and converted into S-polarized light and emitted.

These processes are performed for each of the groups of the hologram elements 572 and 573 and the retardation plate 574 arranged in plurality, and the light waves passing through the second lens group 571 are emitted with the same polarization direction. In addition, since the luminous flux is bundled in combination with the integrator, the polarization conversion can be performed without changing the width of the luminous flux from the light source significantly.

The light beams having the same polarization directions as described above are incident on the image display elements 578 such as polarized liquid crystal display elements as parallel light beams by the field lens 575 and the condenser lens 576, and luminance modulation is performed for each pixel. After that, the projection lens 579 is used to project the enlarged image on the screen 579.

When the polarization conversion was performed with or without the polarization conversion element 570 as described above, the luminance on the screen was compared, and when the polarization conversion was performed, the brightness was increased by about 30%, resulting in a bright image. You can get it.

(Embodiment B3-6)

An example of another polarization conversion element in which a hologram element as shown in the above embodiment B1 or embodiment B2-1 is used will be described.

As shown in FIG. 26, a pair of polarization conversion elements 560 similar to the above-described embodiments B3-4 may be provided so as to be an object with respect to the optical axis of the reflector 534, so that the polarization conversion elements 590 may be configured. . By configuring in this way, since the reflector 534 is arrange | positioned in the width direction center of a polarizing lighting device, for example, an equal space is formed in both sides, and the other components in the apparatus to which this polarizing lighting device is applied, etc. Easy to deploy

(Embodiment B4-1)

An example in which the projection image display device constructed by using the polarization splitting element 510 of Embodiment B2-1 (Fig. 13) is constructed. As the hologram element constituting the polarization splitting element 510, those shown in Embodiment B1 or Embodiment B2-1 (Figs. 10, 18 and the like) can be used. Here, when the hologram element of Embodiment B1 is used, it is used with the predetermined voltage applied between ITO.

As shown in FIG. 27, the projection image display device 600 includes a lamp 533, a reflector 534, a polarization illumination device 601 composed of a polarization splitting element 510, and an integrator, and a lamp 533. The output light beam from the light is reflected by the reflector 533, and the reflected output light beam β is reflected through the polarization separation element 510 and the integrator 541, for example, an image display element 547 such as a transmissive liquid crystal panel. The image is displayed by enlarging and projecting the luminance modulated light flux on the screen (not shown) by the projection lens 602.

Next, the polarization separating element 510 and the integrator used in this projection image display apparatus 600 will be described. The polarization splitting element 510 used in the present invention is composed of the first hologram element 511 and the second hologram element 512, as described in Embodiment B2-1, and the P polarized light is driven straight ( While outputting the S-polarized light at an output angle of approximately -7 degrees.

In addition, each of the first microlenses constituting the first lens group (first fly's eye lens) 542 is respectively applied to each second lens constituting the second lens group (second fly's eye lens) 543. Open the image of the lamp. P polarized light And S-polarized light δ are imaged at different positions. For example, a phase difference plate 544 which is a half wave plate (λ / 2 plate) as a polarization plane rotating means is provided at a portion where the S polarized light δ forms an image, and the S polarized light transmitted through the phase difference plate 544. ? is almost converted to S-polarized light and output. P polarized light The polarization direction of the polarizing plate included in the image display element 547 determines whether the polarization plane is rotated with respect to any polarization component in the S-polarized light δ.

The second lens group 543 forms an image of each of the microlenses constituting the first lens group 542 over almost the entire surface of the display image area in the image display element 547, so that the brightness of the display image is uniform. Castle is secured.

By constructing the polarization lighting device 601 as described above, unpolarized light output from the lamp 533 can be efficiently converted into P-polarized light, and high projection efficiency can be realized. In addition, the polarization splitting device 510 as described above is easy to manufacture and can be configured at low cost. In addition, since the polarization splitting element 510 has a small dimension in the optical axis direction, it is possible to easily configure a polarization splitting element having a compact and high separation efficiency. Further, by using the polarization splitting element as described above, it is possible to easily realize the projection type image display apparatus having high light utilization efficiency.

In addition, if the arrangement of the lamp 533 and the reflector 534 is different, the polarization conversion element 530 or the like as shown in Embodiments B3-1 to 3-3 (FIGS. 21 to 23) may be used.

As the lamp 533, a metal halide lamp, a halogen lamp, a xenon lamp, an ultrahigh pressure mercury lamp, or the like can be used. However, it is preferable to use one having a small light emitting area.

(Embodiment B4-2)

An example of a so-called three-plate projection image display apparatus including three transmissive image display elements and optical elements of a color separation system and a color synthesis system and capable of displaying color images will be described.

This image display apparatus is provided with a color synthesis system element 620 shown in FIG. 28B below the color separation system element 610 shown in FIG.

The color splitter element 610 comprises a polarization illumination device 610 comprising a polarization conversion element as shown in embodiment B4-1, a dichroic prism 611 and a total reflection mirror 612 to 614. The light output from the polarization illumination device 610 is decomposed into light of each wavelength of R (red), G (green), and B (blue). On the other hand, the color synthesizing element 620 is composed of a total reflection mirror (621 ~ 623), an image display element (624 ~ 626), a dichroic prism (625), and a projection lens 628, the color resolution element After the light of each wavelength induced at 610 passes through the image display elements 624 to 626, color synthesis is performed, and the projection lens 628 projects the image on the screen 629.

In this image display apparatus, the substantially parallel luminous flux output from the lamp 533 through the reflector 534 is polarized by the polarization splitting element 510 and the integrator 541 as described in Embodiment B4-1. At the same time, the uniformity in the plane of the light beam is maintained, and then incident on the dichroic prism 611. The dichroic prism 611 has a configuration in which filters of wavelengths of respective bands are formed therein, and the white light from the polarization illuminator 601 corresponds to the wavelength filter, and R, G, The light is decomposed into light corresponding to each wavelength of B, and the light is emitted in the direction indicated by the arrow in the figure. Here, the dichroic prism 611 has the same function as when the two-layer dichroic mirror is used, but for the prism configuration, since the color can be resolved without using a large space. Therefore, 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 guided to the color synthesis system element 620 on the lower side. The light of each color guided to the color composition element 620 in the color separation element 610 is reflected by a 90 ° change in the traveling direction through the total reflection mirrors 612 to 623, and is a transmission type corresponding to the light of each color. Luminance is modulated by the image display elements 624 to 626, and then enters the dichroic prism 627. This dichroic prism 627 has a function opposite to that of the dichroic prism 611, and is divided into light of R, G, and B colors, respectively, and performs color synthesis of the incident light. Exits toward the direction of the projection legs 628. Light emitted from the dichroic prism 627 is projected onto the screen 629 by the projection lens 628, and is displayed as an enlarged image.

As described above, by providing a polarization conversion element that matches the polarization direction of the light beam output from the reflector 534, an image display apparatus capable of improving light utilization efficiency and displaying a bright image can be configured.

In addition, in the case of applying a polarization conversion element or the like to an image display device for displaying a color image as described above, in the production of the hologram element, multiple exposure is performed at the interference height of light by red, green, and blue light, A hologram element optimized for diffraction of light may be laminated or one having a structure may be used.

Instead of the polarization splitting element 510 and the retardation plate 544, a polarization converting element 560 or the like as shown in the embodiments B3-4 to 3-6 (Figs. 24 to 26) is used. Similarly, high light utilization efficiency can be obtained.

In addition, the same effect can be obtained even if the above-mentioned polarization conversion element 550 is arrange | positioned between the integrator 541 and the dichroic prism 611. As shown in FIG. In addition, three polarization conversion elements (and inter) between the dichroic prism 611 and the image display elements 624 to 626, that is, the color separation and corresponding to the light of each color, are connected between the polarization conversion element 550 and the like. Greater) may be provided. In this case, since the polarization conversion elements are separately provided in correspondence with the light of each color, the hologram element is optimized to reduce the influence of wavelength dispersion according to the wavelength of each color, that is, corresponding to each wavelength. The periodic structure is formed, etc. can be used, and the light utilization efficiency can be further improved. Similarly, the integrator may be provided after the dichroic prism 611.

In addition, if the arrangement of the lamp 533 and the reflector 534 is different, the polarization conversion element 540 or the like as shown in Embodiments B3-1 to 3-3 (FIGS. 21 to 23) can be used.

Also in the case where the reflectors are provided in the arrangement as shown in Fig. 28, the polarization conversion element is placed between the dichroic prism 611 and the image display elements 624 to 626, i.e., after color separation. In the case where three corresponding polarization conversion elements (and integrators) are provided, the above polarization conversion elements can be applied. A total reflection mirror 612 or the like for guiding) can be used as the total reflection mirror 531 of the polarization conversion element. Further, as described above, ones adapted to the wavelength of each color may be used as the hologram element.

In addition, when a polarization conversion element was installed in each path after color separation, the brightness on the screen of the color-synthesized image and the polarization conversion element were increased by about 30% compared with the case where no polarization conversion element was used. The same was true for the transmission type described above and the reflection type described later. Thus, polarization conversion using the diffractive optical element is effective also for color display.

In addition, in the structure shown in FIG. 23, it is also possible to use the means to change the thickness of the phase plate in surface in order to correct | depend the dependency of the polarization characteristic by the incident angle of a phase plate.

(Embodiment B4-3)

An example of a three-plate projection type image display apparatus capable of displaying color images using a reflective image display element in a configuration similar to the above embodiments B4-2 will be described.

In this image display apparatus, the color synthesizing element 630 shown in Fig. 29B is provided below the color separation element 610 shown in Fig. 29A.

The color separation element 610 is the same as that shown in Embodiment B4-2 above. On the other hand, the color synthesizing element 630 has polarizing beam splitters 631 to 633 provided in place of the total reflection mirrors 621 to 623, and the transmissive image display elements 624 to 620, compared to the embodiments B4-2. The reflection type image display elements 634 to 636 are provided in place of 626.

The polarization beam splitters 631 to 633 are configured to reflect only light in a predetermined polarization direction, but in fact, the light guided by the color splitter element 610 is light whose polarization direction is matched by the polarization conversion element. Light is reflected to enter the image display elements 634 to 636. The light incident on the image display elements 634 to 636 is modulated and reflected by the polarization direction according to the display image of each color, and then enters the polarization beam splitters 631 to 633, so that only light in a predetermined polarization direction is transmitted. The modulation in the polarization direction is converted into luminance modulation and made visible. Thereafter, color synthesis is performed by the dichroic mirror 637 in the same manner as in the embodiment B4-2, and the image is projected onto the screen 629 by the projection lens 628.

In the reflective image display device as described above, a polarization converting element that matches the polarization direction of the light beam output from the reflector 534 is also provided, whereby an image display device capable of displaying a bright image by improving light utilization efficiency is provided. Can be configured.

Also in this image display apparatus, various modifications as described in the above embodiments B4-2 are equally possible.

(Embodiment B5-1)

An example of an image display apparatus provided with a hologram element will be described.

In the image display apparatus, as shown in FIG. 30, hologram elements 702 and 703, which are diffractive optical elements, are provided on the screen of the liquid crystal element 701, and have lamps 704a and reflectors 704b on their back sides. The light source 704 is provided and comprised.

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

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

As the liquid crystal element 701, for example, a twisted nematic liquid crystal in which the direction of liquid crystal molecules is bent at 90 degrees on the incident surface side and the emission surface side of light 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. By the way, in the pixel ON to which a predetermined sufficient voltage (a voltage sufficient to completely switch the liquid crystal) is applied to the liquid crystal, the liquid crystal molecules are distorted, and the liquid crystal molecules are isotropically standing with respect to the incident surface of light. It becomes a state (homeotropic). For this reason, when P-polarized light enters the pixel, the polarization direction passes through the liquid crystal element 701 while maintaining the polarization state without being modulated. On the other hand, in the pixel OFF where no voltage is applied to the liquid crystal, the liquid crystal molecules are in a state where the liquid crystal molecules are bent at 90 degrees in the thickness direction from the incident surface to the exit surface. By the way, when P-polarized light enters the pixel, the P-polarized light passes through the liquid crystal element 701 from the incident surface to the exit surface, thereby causing the polarized surface to be canceled by the twisted nematic effect caused by the liquid crystal's warpage. Rotate 90 °. Therefore, after passing through the OFF pixel, the light is emitted as S-polarized light.

As the hologram elements 702 and 703, for example, the hologram elements as shown in the above embodiment B1 or embodiment B2-1 are used. Here, when the hologram element of Embodiment B1 is used, it is used with the predetermined voltage applied between ITO. The hologram elements 702 and 703 have different diffraction effects depending on the polarization direction as described above, and have diffraction characteristics exhibiting high diffraction efficiency in one predetermined direction.

Specifically, for example, since the S-polarized light of the light incident on the hologram elements 702 and 703 moves as an abnormal light component, it is modulated by the refractive index distribution of the periodic structure formed in the hologram elements 702 and 703. The upward direction at 30 is bent to exit. On the other hand, since the P-polarized light acts as an image light component with respect to the hologram elements 702 and 703, it is not affected by the refractive index distribution formed by the periodic structure of the hologram elements 702 and 703, and passes through an isotropic uniform refractive index medium. The same behavior as in the above case is shown. For this reason, the P-polarized light passes through the hologram elements 702 and 703 as it is.

By the way, when light including P-polarized light and S-polarized light from the light source 704 enters the hologram element 702, the S-polarized light is diffracted as described above and hardly enters the liquid crystal element 701, and P Only polarized light passes through the hologram element 702 and enters the liquid crystal element 701. P-polarized light incident on the liquid crystal element 701 is emitted as P-polarized light in the ON pixel as described above, while converted into S-polarized light in the OFF pixel and emitted. That is, the light emitted from the liquid crystal element 701 becomes different polarized light depending on the ON and OFF of the pixel at the passing position.

When the light emitted from the liquid crystal element 701 enters the hologram element 703, like the hologram element 702, the S-polarized light is diffracted so that only the P-polarized light goes straight. That is, the light passing through each pixel of the liquid crystal element 701 is different from the direction emitted from the hologram element 703 according to the ON and OFF of the pixel. Therefore, from the observer who visually sees the image display device in a direction almost normal to the display surface, the light passing through the OFF pixel is not viewed because it is emitted out of the viewing area by the diffraction action of the hologram element 703. The light passing through the ON pixel passes straight through the hologram element 703 and enters the viewing area of the viewer, and is recognized as a light pattern.

Next, an example of the actually produced image display apparatus will be described.

In this image display apparatus, as the light source 704, one which passed a green filter to a fluorescent lamp is used to emit light having a wavelength of about 0.55 mu m. As the liquid crystal element 701, one having a resolution of VGA (640 x 480) of about 3 inches was used. When an image signal was input to this and observed from almost the normal direction (front face) of the display screen, the image according to the image signal incident on the liquid crystal element 701 was correctly recognized. The contrast was about 10: 1. In addition, when the observation position is shifted in the direction in which the S-polarized light passing through the hologram element 703 is diffracted (above in FIG. 30), the image whose contrast is reversed with respect to the preceding image is recognized. The hologram elements 702 and 703 of the refractive index distribution type composed of an optical medium having refractive anisotropy as described above are formed by combining the liquid crystal element 701, without blocking (absorbing) the light incident to the OFF pixel. By emitting the light outside the viewing area of the observer, an image can be displayed and an image display device having good visibility can be manufactured. Furthermore, as in the case of using a polarizing plate, heat generation due to absorption of light does not occur.

Further, by controlling the voltage applied to each pixel, the polarization direction of the light passing through the liquid crystal can be set in the same state as that of the P-polarized light and the S-polarized light, that is, the elliptical polarized light, in accordance with the voltage. At this time, the light incident on the hologram element 703 is divided into a component that is straight and a component that is diffracted according to the voltage applied to each pixel, so that halftone display is also possible.

In the above example, the liquid crystal element 701 has been described with a twisted nematic type, but may be of any type as long as it has an action of modulating the polarization direction with respect to incident light. In addition, a super twisted nematic (STN) liquid having a bending angle of 90 degrees or more can be used in the same manner. Further, VA (such as homogeneous orientation of the liquid crystal molecules in the thickness direction thereof and homogeneous alignment with respect to the application of an electric field, or change from homotropic orientation to homogeneous orientation) can be obtained. The same effect can be obtained by using a liquid crystal of Verticla Aligne) mode.

In addition, it is also possible to use ferroelectric liquid crystals and antiferroelectric liquid crystals in which the alignment of liquid crystal molecules differs depending on the polarity of the electric field.

The liquid crystal element 701 as described above is usually the same as the liquid crystal panel used as the liquid crystal display. Therefore, the above-described image display apparatus can be configured only by replacing the front and rear polarizing plates used in the liquid crystal element with the hologram elements 702 and 703 of the present invention, and other illumination systems, driving systems, and the like are applied as they are. It is very versatile because it can be done.

(Example B5-2)

The image display device shown in Fig. 31 was constructed using the same hologram elements 702 and 703 as in the above embodiment B5-1. That is, the arrangement of the light source 704 was arranged near the lower side of the hologram element 702, and irradiated with light from an oblique side to form a so-called side light. That is, the light source 704 used the thing which provided the green filter to the fluorescent lamp similarly to Embodiment B5-1. About other structure, it carried out similarly to Embodiment B5-1.

In this image display apparatus, the P-polarized light of the light emitted from the light source 704 passes through the hologram element 702 as it is, and does not enter the liquid crystal element 701. In addition, the S-polarized light is bent at 90 ° with respect to the display screen in the hologram element 702 to enter the liquid crystal element 701. Light passing through the liquid crystal element 701 is incident on one hologram element 703 even when the polarization direction is modulated in response to an application signal of the pixel. Here, the S-polarized light is diffracted upward in the same plane and emitted outside the visible region of the observer. The P-polarized light passes through the hologram element 703 as it is, and is viewed by an observer. When the normal direction of the hologram element 703 orientation display screen was observed from the observer's position, the image corresponding to the input image signal was surely recognized. In addition, it was also possible to observe the external landscape through the hologram elements 702 and 703 from the position near the observer. As described above, the image display device configured as described above can be visually recognized by switching the image display and the external scene simultaneously, or can be used as a so-called see-through type display.

(Embodiment B5-3)

As in the embodiment B5-1, one hologram element 702 was used to constitute the image display device shown in FIG. That is, it is set as the structure which displays an image using external light, such as natural light or room light, without having a light source inside an image display apparatus. In addition, the liquid crystal element 701 used the same thing as Embodiment B1.

The display principle of this image display apparatus will be described below.

First, when external light 701 including P-polarized light and S-polarized light enters the hologram element 702, the P-polarized light component is transmitted as it is without being modulated by the hologram element 702, and the liquid crystal element 701 Hardly incident on. On the other hand, the S-polarized light is diffracted by the hologram element 702, so that generally the entire light is incident on the liquid crystal element 701. Light incident on the liquid crystal element 701 passes through the region of each pixel and is reflected by the mirror 711. The mirror 711 can be made of a metal, a dielectric multilayer, or the like. As the material produced, aluminum was deposited on a glass substrate.

The light reflected by the mirror 711 again passes through the region of each pixel of the liquid crystal element 701, and the polarization direction is modulated in response to the voltage applied to each pixel, and is incident on the hologram element 702. The S-polarized light incident on the hologram element 702 is diffracted upward in the same plane and is emitted out of the viewer's field of view. In addition, since the P-polarized light passes through the hologram element 702 as it is, the viewer is visually recognized, and the image is visually recognized corresponding to the signal voltage applied to each pixel of the liquid crystal element.

When the reflective image display device using the mirror as manufactured above was observed by the illumination of the room light, an image having a pattern of contrast was recognized. Contrast was about 10: 1. Although a white light source which is room light was used, there was almost no deterioration in image quality due to color bleeding. These S polarized light diffracted by the hologram element 703 in the return path differ in the diffraction direction depending on the wavelength. However, if the diffraction angle is set larger than that of the observer's visible region, the polarized light is out of the recognition region, and the influence of the diffraction angle due to the wavelength is affected. Is thought to be almost a problem.

Therefore, in the reflection type image display apparatus using the external light configured as described above, it is possible to clearly recognize the image, and furthermore, it is suitable for low power consumption and miniaturization since no internal backlight is required.

(Embodiment B5-4)

As shown in Fig. 33, an image display apparatus of a combined type of external light and internal light source constructed using the hologram elements 702 and 703 as in the embodiment B5-1 will be described.

In this image display apparatus, the hologram elements 702 and 703 are the same as those shown in the embodiment B5-1, but the hologram elements 702 are arranged in a state rotated 90 degrees in the same plane as in the embodiment B5-1. . Therefore, the hologram element 702 exhibits no diffraction effect on the S-polarized light but has a diffraction effect on the P-polarized light. That is, the hologram elements 702 and 703 are configured so that the dependence of the polarization direction on the P-polarized light and the S-polarized light is reversed. That is, the same function can be provided also by performing the alignment process such that the homogeneous alignment direction of the initial liquid crystal is 90 degrees in the hologram element shown in FIG. That is, it is possible to determine which polarized light has a diffraction effect by how the alignment direction of the liquid crystal molecules is set for the incident light.

The liquid crystal element 701 is the same as that used in Embodiment B5-1. In addition, the mirror 711 is formed by vapor deposition of the same aluminum as Embodiment B5-3. The light source 704 is a fluorescent lamp and was used as a white light source.

Here, in FIG. 33, the solid arrow indicates the propagation of external light, and the dashed line arrow indicates the propagation of light from the light source 704.

First, the display operation by the light from the light source 704 will be described. The light including P-polarized light and S-polarized light from the light source 704 disposed on the oblique side of the hologram element 702 as a side light is transmitted through the S-polarized light by the hologram element 702 without being subjected to diffraction. The P-polarized light is generally bent in the direction of 90 ° with respect to the 90 ° display screen by diffraction and enters the liquid crystal element 701.

The P-polarized light incident on the liquid crystal element 701 is modulated in each pixel of the liquid crystal element, the polarization direction is changed, and the traveling direction is changed by the action of the hologram element 703. As a result, the observer can visually recognize the image information corresponding to the input image signal.

Next, the display operation by the external light 701 will be described. The P-polarized light of the external light 701 passes through the hologram element 703 without being modulated and does not enter the liquid crystal element 701. As for the S-polarized light, the traveling direction is bent by the diffraction action of the diffractive optical element, and usually enters the liquid crystal element 701. Since the S-polarized light passing through each pixel of the liquid crystal element 701 is not diffracted with respect to the hologram element 702, it is transmitted as it is and reflected by the mirror 711. After passing through the hologram element 702 again, it is incident on each pixel of the liquid crystal element 701, and the polarization direction is modulated for each pixel to enter the hologram element 703. The S-polarized light passing through the ON pixel is diffracted by the hologram element 703 and exits out of the viewer's visible region. In addition, the P-polarized light passing through the OFF pixel passes through the hologram element 703 as it is and is recognized as a bright pattern to the viewer.

Here, in the light from the light source 704 and the external light, the light and dark patterns corresponding to ON and OFF of the liquid crystal element are reversed. This can be dealt with by inverting the pattern of the video signal in correspondence with the selection of the light source.

In addition, strictly speaking, light from the light source 704 is only transmitted once to the liquid crystal element, whereas the external light 701 is reflected by the mirror and passes through the two liquid crystal elements of the return path and the return path. For this reason, the modulation ratio in the liquid crystal element 701 is different. In this regard, since the modulation degree of one pass and two passes can be estimated in advance, it is possible to cope by correcting the video signal in accordance with the selection of the light source.

As described above, by setting the polarization dependencies of the hologram elements 702 and 703 to be different, both the transmission mode and the reflection mode can be achieved.

As a result of observing the actually produced image display apparatus, in a dark room, the image can be visually recognized by using the light source 704, and the original image of the bright illumination light can recognize the image which does not light up the light source 704. Could. By using this image display device in this way, it is possible to select a light source in accordance with an environment such as a dark place or the original of bright illumination light. Therefore, it is possible to improve the efficiency of power consumption and to improve the visibility of images under various environments.

Therefore, the use method which detects the brightness of illumination light in the environment where an image display apparatus is used, and selects a light source automatically or sets the intensity of a light source is also possible, and it is possible to further improve display capability by this.

(Embodiment B5-5)

FIG. 34 shows an image display apparatus constructed by combining the color filters 721 with the same hologram elements 702 and 703 as in the embodiment B5-1. As the light source 704, a fluorescent lamp was used as a white light source through the filter. In addition, the liquid crystal element 702 has the same structure as the liquid crystal element 720 of the embodiment B5-1, but has a pixel density of three times, and red (R), green (G), Three pixels corresponding to the areas of blue (B) become a set so that color images can be displayed at the same pixel density as that of the liquid crystal element 720.

In addition, the color filter 721 selectively transmits light having a wavelength of any one of R, G, and B, and absorbs light having a different wavelength, for each region corresponding to each pixel of the liquid crystal element 720.

In this image display apparatus, the light including P-polarized light and S-polarized light emitted from the light source 704 is diffracted upward by the hologram element 702 in the same plane. Therefore, the S-polarized light does not enter the color filter 72, but only the P-polarized light enters the color filter 721.

Light corresponding to each wavelength of R, G, and B passing through the color filter 721 is incident on each pixel of the liquid crystal element 720. The polarization direction is modulated in correspondence with ON and 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 viewer. Further, the light passing through the OFF pixel is diffracted upward in the figure by the hologram element 703, so that it is out of the viewing area of the observer and becomes a dark pattern which is not recognized as the light intensity by the observer.

In Fig. 34, for the sake of simplicity, the case where each pixel corresponding to R, G, and B is ON and OFF is shown. By controlling the electric field applied to each pixel to which light of each wavelength is incident and passing the hologram element 703, the viewer reaches the light of the selected color among the light of each wavelength of R, G, and B. Therefore, the display of the color image is possible as each combination.

Here, the influence of the wavelength dispersion of the hologram element 703 on each wavelength may be set so that the diffraction angle is set to be large and set so as to be outside the viewing area of the observer even in short wavelength light having a small diffraction angle. As a result, any of the light of each wavelength passing through the pixel corresponding to OFF is diffracted out of the observer's field of view by the hologram element 703, so it is not recognized as the light intensity, and problems such as color mixing do not occur.

In addition, light passing through the ON pixel is not subjected to diffraction in the hologram element 703. However, when the liquid crystal material forming the hologram element 703 has wavelength dispersion, Δn = Ne-No may be different depending on the wavelength, so that the inside of the element is not regarded as an isotropic medium. In this case, an angular difference is generated in the light of each wavelength transmitted, and the observer is visually recognized by color bleeding or the like. However, in the case of transmission, if the distance from the observer's hologram element 703 is not slightly apart, no significant image quality deterioration occurs.

When the 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, it was almost impossible to observe clear color images with little mixing or color bleeding. It was possible.

Note that the combination of the color filters herein is not only used in the configuration of FIG. 34 but can also be applied to the reflection type of FIG. 32, the combined type of transmission and reflection of FIG. 33, or modified configurations thereof.

(Embodiment B5-6)

The hologram elements 702 and 703 of the image display device of the above embodiment B5-5 are manufactured by carrying out multiple exposure with light having respective wavelengths of R (0.65 m), G (0.55 m) and B (0.45 m). You may use one. Hereinafter, a manufacturing process of such a hologram element will be described.

First, in Embodiment B2-1, a liquid crystal sample is produced in the same manner as in the case of manufacturing the hologram element in FIG. This is set in an optical system device using an Ar laser, and exposure is first performed by an interference height corresponding to a wavelength of G (0.55 mu m) as a first exposure step. Next, the angle of the mirror (reflecting mirror) is changed, the above first exposure stroke is repeated, and exposure corresponding to the wavelength of R (0.65 µm) is performed. Moreover, the interference height corresponding to B (0.65 micrometer) is formed in the same manner, and exposure is performed. Thereafter, in the same manner as in the embodiment B2-1, a second exposure stroke for irradiating the liquid crystal sample with uniform light can be performed to produce a hologram element in which the interference height is superimposed.

The hologram element manufactured as described above was used in place of the hologram elements 702 and 703 of FIG. 34, and the color image signal was input to the liquid crystal element 701 and observed from the observer's position. Since it is optimized for any of the wavelengths of R, G, and B, a clear image can be recognized without problems such as color bleeding and mixed color. In addition, even if the observation position was moved back and forth by about 30 cm, the effect of deterioration of image quality did not occur.

(Embodiment B5-7)

The hologram elements 702 and 703 of the image display device of the above embodiment B5-5 are exposed to light of each wavelength of R (0.65 m), G (0.55 m) or B (0.45 m). You may use what laminated | stacked the produced three hologram elements.

Instead of the hologram elements 702 and 703 of FIG. 34, the above-described hologram elements are used, and color image signals are inputted to the liquid crystal element 701 and observed from the observer's position. For each wavelength, diffraction was independently performed by diffraction optical elements in each layer, and wavelength dispersion was relaxed. As a result, it was possible to recognize a clear image without problems such as smearing and mixing of the lines. 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 B5-8)

The image display device such as the above embodiment B5-1 can also be applied to an image display / use lighting device. Hereinafter, an example of a device capable of displaying road traffic information in a tunnel and illuminating the tunnel will be described.

As shown in Fig. 35, the image display device 731 is provided on the wall surface 732 of the tunnel. This image display device 731 has the same configuration as the image display device described in the embodiment B5-1, for example, so that the emission direction of the diffracted light in the hologram element faces the traveling direction of the vehicle 733 traveling in the tunnel. It is installed. That is, in the embodiment B5-1, an example of viewing the display image from the normal direction (front) of the display screen has been described. However, in the example in which the display operation is performed, the contrast is different from the image visually recognized from the front by the diffracted light. The reversed image is displayed. By the way, by inputting image data whose intensity has been transmitted in advance as image data input to the image display apparatus, it is possible to display an image that can be visually recognized from the direction inclined with respect to the normal of the display screen by diffracted light.

Here, the emission direction of the diffracted light, that is, the viewing direction of the display image 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 for which the display image needs to be viewed from the inclined direction.

In addition, when displaying an image by diffracted light, the light which permeate | transmitted the hologram element exits to the normal direction of a display screen on the contrary. The image by this outgoing light cannot be recognized from the inclined direction. It is possible to use it as an illuminating device because it serves as an illuminating light in a dark environment at night or in a tunnel. That is, a device in which both functions of the image display device and the lighting device are combined can be configured. Thus, it becomes possible to have the functions of an image display device and an illumination device. In a liquid crystal display using a conventional polarizer, light not used for image display is absorbed by the polarizer, and the hologram element is used as described above. This is because the display device used emits equally the transmitted light and the diffracted light in principle.

In the present invention, the hologram elements 702 and 703 divide the light into a feature of the image display apparatus.

That is, when the plurality of image display devices 731 are disposed on the wall surface 732, a method of enabling the viewer to recognize the image information step by step according to the traveling position of the vehicle is also possible. It is effective when it is made to perform easily.

In fact, when the image display device 731 was placed in a laboratory that mimics the structure in the tunnel as shown in FIG. Moreover, it was also confirmed that the light radiate | emitted to the front surface of the image display apparatus 731 is achieved by using together with the role as illumination light in a dark laboratory.

Such an image display and lighting device is not limited to a tunnel, and can be applied to traffic information display and lighting on a normal trunk road or a highway, and is applicable to a usage method of preferentially displaying image information in other specific directions. Needless to say.

(Embodiment B5-9)

An example of an image display apparatus having a polarization conversion element constructed by using the same hologram element as in the above embodiment B5-1 will be described.

This image display apparatus is provided with hologram elements 741 to 744 arranged on the same plane instead of the hologram elements 702 of Embodiment B5-1. In addition, retardation plates (λ / 2 plates) 745 and 746 are provided between the hologram elements 743 and 744 and the liquid crystal element 701. The light source 704 used the thing which passed the green filter to the fluorescent lamp like Example B5-1. About other structure, it is the same as that of Embodiment B5-1.

In this image display apparatus, the P-polarized light of the light emitted from the light source 704 passes through the diffractive optical elements 741 and 742 as it is and enters the liquid crystal element 701. In addition, the S-polarized light is usually diffracted almost transversely at an angle of 90 ° to the hologram elements 741 and 742 and enters the hologram elements 743 and 742 arranged laterally, respectively. Light incident on the hologram elements 743 and 744 becomes hologram elements 743 and 744 and is usually diffracted at an angle of 90 degrees. The light diffracted by the hologram elements 743 and 744 is rotated by 90 degrees by the retardation plates 745 and 746, and is generally incident perpendicularly to the liquid crystal element 701 as P polarized light.

That is, the polarization conversion elements are constituted by the hologram elements 741 to 744 and the retardation plates 745 and 746, and the light from the light source 704 is a light wave whose polarization plane coincides (in this case, P polarized light). In this case, the liquid crystal element 701 is incident on the liquid crystal element 701. Therefore, the light utilization efficiency becomes high (in theory, about twice), and a bright image can be displayed.

It is also possible to widen the irradiation area of the light source 704, to enlarge the irradiation area of the light from the light source 704 having a small area, and to perform image display, which is also effective in miniaturization and low power consumption of the system. .

The light passing through the liquid crystal element 701 is modulated in the polarization direction in response to the application signal of the pixel and is incident on one hologram element 703.

In this case, the S-polarized light is diffracted above the paper surface and is emitted out of the viewer's field of view.

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

When the direction of the hologram element 703 was observed from the observer's position, the image corresponding to the applied input signal was certainly recognized.

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

(Example B5-10)

Another example of a small image display device having a polarization conversion element constructed using the same hologram element as in the above-described embodiment B5-1 will be described.

37 shows an outline of a small display device constructed in Embodiment B of the present invention. Light waves from the light source 704 are incident on the hologram element 751 from the lateral direction, and P-polarized light is usually diffracted by 90 degrees by this diffraction optical element and enters the liquid crystal element 701.

The S-polarized light passes through the hologram element 751 and enters one hologram element 752. The diffractive optical element 752 is formed to have a refractive index distribution with respect to the S-polarized light, and the S-polarized light incident on the hologram element 752 is usually diffracted by 90 degrees and exits. Thereafter, the polarization plane is rotated 90 degrees through the? / 2 field 753 to enter the liquid crystal element 701 as P-polarized light.

Therefore, as in the embodiment B5-10, almost all of the light amount from the light source 704 can be used for display of the liquid crystal element. In addition, a combination of an external light source and an internal light source, as configured in the embodiment B5-4, or a see-through function for the configuration of inciding light from the lateral direction is also possible.

In the actually manufactured image display apparatus, as a light source 704, a fluorescent lamp was used to pass through a green filter, and light having a wavelength of about 0.55 mu m was emitted. As the liquid crystal element, a small liquid crystal panel having a resolution of VGA (640 x 480) of about 0.9 inches was used. When an image signal is input thereto, the light passing through the liquid crystal element 701 is modulated in the polarization direction in response to the application signal of the pixel and is incident on one hologram element 703.

In this case, the S-polarized light is diffracted above the paper surface and is emitted out of the viewer's field of view. The P-polarized light passes through the hologram element 703 as it is and is recognized by the viewer.

This time, the magnification optical system 754 was used for the light output side of the hologram element 703. Here, a planar Fresnel lens was used as the magnification optical system. As the magnification optical system, it is also possible to use a convex lens or a liquid crystal lens using an in-plane change in refractive index. When the magnification optical system is composed of a thin lens, it is desirable to form a compact system.

When the direction of the hologram element 703 was observed from the observer's position, the image corresponding to the applied input signal was certainly recognized. In addition, regardless of whether a 0.9-inch small liquid crystal panel is used at this time, the magnified optical system 754 allows the observer to enlarge the display image by the distance from the hologram element 703 so that the viewer can recognize it clearly. It was.

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

(Embodiment B6)

An image display apparatus constructed using the hologram element shown in the above embodiment B1 will be described.

38A is a block diagram of the image display device. In this image display apparatus, the hologram element 820 according to the present invention is used for the backlight unit of the transmissive liquid crystal panel 819.

The light beam 824 from the light source 823 is incident from the cross section of the light guide 821, and is a substrate of the liquid crystal panel 819 by the hologram element 820 of the present invention provided on the rear surface while propagating the light guide 821. Is diffracted almost in the normal direction. The light beam 822 incident on the liquid crystal panel 819 is modulated to display an image.

In addition, a reflective mirror 823 is provided on the rear surface of the hologram element 820 to reflect light that has passed through the hologram element 82. For example, light is reflected on the reflective mirror 823. It is preferable to form the dot which does not scatter (the well-known technique which is disclosed in many numbers other than the prior art example 7) not scattering.

The liquid crystal panel 819 may be a transmissive type, and any type of liquid crystal panel can be used regardless of its driving method and liquid crystal material. Moreover, the reflective liquid crystal panel used also as a transmissive type may be sufficient according to the brightness of external light.

As the light source 823, for example, a CCFT can be used, and a reflecting mirror 825 may be provided as described in large number starting with the conventional example 8. As the light guide 821, a resin material such as acryl can be mainly used. For example, as disclosed in many of the prior arts, such as Japanese Patent Application Laid-Open No. 9-5743 and the like, it is also possible to have a wedge shape.

Since the basic function of the hologram element 820 is to diffract a specific polarization component among the unpolarized light beam 824 incident on the hologram element in a substantially normal direction of the liquid crystal panel 819 and within a specific solid angle, It functions as a hologram element with or without it, or as a simple isotropic medium.

That is, as shown in Figs. 39A and 39B, for example, it is possible to function as a hologram element when no voltage is applied and to function as an isotropic medium when voltage is applied. In the case of functioning as a hologram element, the hologram element 820 according to the present invention selectively diffracts only a specific polarization component in a near normal direction of the liquid crystal panel within a specific solid angle in the non-polarized incident light beam 824.

In this case, in the case where the liquid crystal panel modulates only polarized light, i.e. specific polarized light, when a polarizing plate (not shown) is provided on the light incidence side, the polarization direction of the polarizing plate (electric field vector of polarized light transmitted by the polarizer) High efficiency can be realized only by generally matching the polarization direction (the vibration direction of the electric field vector) of the polarized light selectively diffracted by the hologram element.

On the other hand, in applying a voltage, the hologram element 820 of the present invention becomes almost an isotropic medium, and the incident light beam 824 penetrates the hologram element 820, and is scattered by the reflection mirror 823 provided on the back side thereof. The luminous flux enters the liquid crystal panel 819. In this case, the output light flux of the liquid crystal panel 819 diffuses almost evenly by the dots provided in the reflecting mirror 823 as in the case of being illuminated by a conventional backlight.

As described above, in the image display apparatus using the hologram element 820 of the present invention, when a voltage is not applied, the liquid crystal panel 819 is viewed from the front in order to diffract the illumination light into a narrow solid angle in a substantially normal direction. The luminance can be made very high, and therefore, the luminance at the time of observing from the front by voltage application can secure a wide viewing angle.

An example in which a hologram element is used as a backlight unit of a liquid crystal panel as in the present invention and the directivity of diffracted light is made to increase the luminance when viewed from the front (viewed from the normal direction of the liquid crystal panel) is, for example, conventionally. Although many examples 7-10 conventional examples are disclosed. In the above example, the hologram element only has a single function of diffracting incident light at all times, and does not change the viewing angle like the hologram element 820 of the present invention.

Incidentally, in Example 1 and Example 2, a switchable hologram element is disclosed. None is disclosed regarding the specific use of the liquid crystal panel as a backlight. As described above, by matching the polarization direction of the polarizing plate of the liquid crystal panel and the polarization direction of light selectively diffracted by the hologram element, high efficiency can be realized at first.

The function of switching the brightness and the viewing angle of an image of the image display device of the present invention is a very valuable function when used as a display of a personal computer or a portable information terminal, for example, regardless of mounting type or notebook type.

That is, when an individual views an image, the viewing angle (meaning that is equivalent to the range in which the image can be visually recognized) does not need to be too wide, but is sufficient in a limited range to the extent necessary for correlation observation at work or the like. According to the present invention, since the image is usually output in the direction of the operator who observes the image from the front, the power consumption of the lamp can be reduced.

On the contrary, when many people observe an image, a wider viewing angle is preferable. Therefore, as in the present invention, the function of changing the viewing angle becomes important in the case where an individual observes an image and when a plurality of people observe an image. However, the viewing angle does not change strictly, and the hologram element 820 of the present invention means that the amount of luminous flux reflected within a certain narrow solid angle can be controlled by an applied voltage.

Next, the manufacturing method of the hologram element used in Embodiment B is demonstrated.

As described in the embodiments B1 and 4-1, the hologram element 820 used in this embodiment B is a photocurable liquid crystal in a cell fabricated from two glass substrates 502 on which an ITO 501 is formed. It can produce by inject | pouring the mixture of a UV-curable liquid crystal and a nonpolymerizable liquid crystal, and illuminating a 2-beam interference height.

However, it is characterized in that the object light is incident almost perpendicularly to the substrate at the angle at which the light beam is incident on the reference light. At this time, by performing two-beam interference exposure in the state where a voltage is applied, a desired interference height is formed, for example, as shown in FIG. 39, and the UV-curable liquid crystal has a weak strength in the strong portion of the interference height. The nonpolymerizable liquid crystal is separated in the part, and the hologram element 820 of the present invention is manufactured.

In actual production, both the object light and the reference light need not be planar piles. For example, the light beams are enlarged within a specific solid angle as object light, and the angle range is substantially the same as the light beam incident on the hologram element propagating through the light guide 21 as reference light. It is preferable to use the light beam incident from the.

In the above structure, for example, the ITO 501 of the hologram element 820 according to the present invention can be patterned, and the refractive index anisotropy can be locally controlled by varying the applied voltage for each region. Thereby, it is also possible to optimize the efficiency of the hologram element 820 locally. Further, as disclosed in, for example, the prior art example 7, the hologram elements may be arranged in a small mosaic shape, and the individual micro hologram elements may be optimized to show maximum efficiency with respect to the incident light wavelength and the incident angle.

38 (b), the λ / 4 plate 27 is provided between the hologram element 820 and the reflecting mirror 823 according to the present invention, and the reflecting mirror 823 is provided with the hologram element. The hologram element 820 is not in parallel with, for example, in a mode of selectively diffracting abnormal light without applying a voltage, for example, to the hologram element 820 according to the present invention by tilting it at about 5 °. The image beam 828 passing through) may be converted into an abnormal beam and incident on the hologram element 820 again.

At this time, since the reflective mirror 823 is inclined, the reflected light beam 829 from the reflective mirror 823 is transmitted through the hologram element 820 according to the angle dependency of the hologram element 820. 820 can enter the liquid crystal panel 819 as the same polarized light (P polarized light in this case) as the light beam 822 reflected by the light beam 822, and the light utilization efficiency can be increased.

As described above, the image display device configured in the present embodiment B can control the amount of light beams output within a specific solid angle by adjusting the applied voltage to the hologram element 820 according to the present invention. This makes it possible to select a narrow but bright image display and a slightly dark but wide viewing angle as necessary.

The image display device configured in Embodiment B of the embodiment is not only used for a display of a stationary or notebook type personal computer, but also used as a portable information terminal, a display for displaying a portable communication device, and a head up display for a vehicle. It is possible.

(Embodiment B7)

An image display apparatus according to the present invention configured as Embodiment B7 of the present invention will be described. The image display device of the present embodiment B is a so-called direct-view liquid crystal panel conventionally. A microcell that surrounds each pixel by a photoorganic phase separation phenomenon by illuminating a mixture of a photocurable liquid crystal and a nonpolymerizable liquid crystal as a liquid crystal material with a lattice-like light (wavelength is the wavelength for curing the photocurable liquid crystal). It forms a structure.

However, after hardening of a photocurable liquid crystal, ne and no have the structure substantially the same as ne and no of a nonpolymerizable liquid crystal, respectively.

With the microcell configuration, the liquid crystal molecules are aligned in the axisymmetric phase stabilized by the photocuring reaction by the self-orientation force in the liquid crystal region, thereby realizing a wide viewing angle and high contrast.

Next, a difference between the conventional example and the image display device according to the present embodiment B will be described. Although the effect which can realize the viewing angle improvement and high contrast by the said microcell is disclosed by the prior art example 6, for example. In the conventional example 6, the light of lattice shape (wavelength is the wavelength for curing the photocurable resin) is simply illuminated on the mixture of the photocurable resin and the liquid crystal, and a microcell structure surrounding each pixel is formed by the photoorganic phase separation phenomenon. Nothing is described about the refractive index anisotropy of the photocurable resin.

Generally, the photocurable resin is slightly but has birefringence and exhibits slight refractive index anisotropy. Therefore, the contrast is good with respect to the luminous flux of vertical incidence when displaying black, but there is a drawback that the portion of the grating is noticeable as a discontinuous region for the luminous flux that is obliquely incident, and the uniformity deteriorates.

However, in the image display apparatus of this embodiment B, the photocurable liquid crystal is cured in the same alignment state as that of the nonpolymerizable liquid crystal when displaying black, and the optical anisotropy of the photocurable liquid crystal is the optical anisotropy of the nonpolymerizable liquid crystal. In order to make it almost the same, the part of a microcell was outstanding at the time of black display, the fall of contrast was suppressed, and the very uniform image was able to be displayed.

(Embodiment B8-1)

40 shows the outline of the optical information processing apparatus using the volume hologram element shown in Embodiment B8-1 of the present invention and shown in Embodiment B2-1. Light emitted by the semiconductor laser 901 that emits polarized light passes through the volume hologram element 521 as it is, and is imaged on the optical storage medium 906 through the quarter wave plate 905 by the imaging lens 904. Is condensed on. In this case, the laser light passing through the volume hologram element 521 is not diffracted and almost all of the light emitted from the semiconductor laser 901 is condensed on the optical memory medium 906.

Next, the light reflected by the optical storage medium 906 passes through the quarter-wave plate 905 again and is converged by the imaging lens 904. At this time, since the reflected light passes through the quarter-wave plate twice, the polarization direction is rotated by 90 ° as compared to when it is emitted from the semiconductor laser 901. Therefore, the reflected light is subjected to diffraction in accordance with a predetermined wavefront formed on the volume hologram 521 and converged on the photodetector 902.

Here, an optical signal is detected for each divided area on the photodetector 902, and a focus shift, tracking shift, and detection of a signal of information on which the optical storage medium is recorded are performed. At this time, the amount of light guided to the photodetector 902 is almost determined by the light utilization efficiency by polarization separation in the path of the volume hologram 521 and the diffraction efficiency in the return path.

41 and 42 show the principle and structure of the volume hologram 521 of the present invention. Fig. 41 shows the index ellipsoid of the uniaxial optical crystal. FIG. 41A shows the index ellipsoid when the optical axis is in the Y direction. At this time, the light having the polarization direction in the Y-Z plane becomes an extraordinary ray and exhibits a refractive index of Ne. Moreover, about the light which a polarization direction exists in an X-Z plane, it becomes an ordinary light and shows the refractive index of No.

FIG. 41B shows the index ellipsoid when the optical axis of the uniaxial optical crystal is tilted 90 degrees 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.

In addition, when the optical axis is in the intermediate state between (a) and (b), the light having the polarization direction in the YZ plane has a median value of the refractive indices of Ne and No (Ne> No) corresponding to the inclined state of the optical axis. . On the other hand, for light having a polarization direction in the X-Z plane, a refractive index of No is always shown regardless of the inclination of the optical axis.

As described above, an optical medium having refractive anisotropy exists in the case of having a refractive index distribution in the range of Ne to No with respect to the incident polarization direction and indices of a refractive index only of No regardless of the inclination of the optical axis.

18 is a diagram showing a cross-sectional structure of a volume hologram element. The inside of this element has a periodic layer structure inclined with respect to the thickness direction from the surface into which light injects. In the adjacent layers, the inclination of the optical axis of the optical medium having refractive index anisotropy is arranged so as to be parallel to the surface of the volume hologram element 521, and the other is arranged in the direction perpendicular to the surface.

Here, the volume hologram element 521 has light having a polarization direction in a direction perpendicular to the surface of FIG. 18 as an ordinary light and light having a polarization direction in a direction parallel to the ground as an ideal light, and these lights are volume holograms. Consider an operation when entering 521.

First, when an image ray is incident, it is treated in the same manner as when light having a polarization direction enters the XZ plane of FIG. 41, so that regardless of the direction of the optical axis of the optical medium constituting each layer, The refractive index is No. As a result, since an even medium having a refractive index of No is present, the image light incident on the light is transmitted as it is as shown in FIG. 18 without being affected by diffraction.

Next, the case where abnormal light enters is considered. In the layer in which the optical axis of the optical medium having refractive index anisotropy is arranged in parallel with the incident surface, the polarization direction of the incident light becomes parallel to the optical axis. This corresponds to the case where light having a polarization direction in the Y-Z plane of FIG. 41 enters an optical medium having an optical axis in the Y direction of (a), and passes through a layer having a refractive index of Ne.

Also, for the layer in which the optical axis of the optical medium is perpendicular to the incidence plane of the volume hologram 521, it corresponds to the case where light having a polarization direction is incident on the YZ plane with respect to FIG. 41 (b). It is handled as having a refractive index of No.

Therefore, for the abnormal light beam, the volume hologram 521 passes through a plurality of layers whose refractive indices in the thickness direction, which is the traveling direction of the incident light, are periodically different. As a result, the incident light is condensed in a specific direction corresponding to the inclination angle of the layer and the pitch of the period and subjected to a so-called black diffraction effect.

As shown in FIG. 18, the abnormal light passes through the volume hologram 521 and changes the optical path corresponding to the layer structure formed inside the element.

As described above, in the configuration of the optical information processing apparatus of FIG. 40, the polarization direction of the light emitted from the semiconductor laser 901 with respect to the volume hologram 521 is set to correspond to the image light ray shown in FIG. At this time, the light emitted from the semiconductor laser 901 is not modulated by the volume hologram 521 and is focused on the optical storage medium 906 by the imaging lens 904 through the quarter wave plate.

The reflected light passes through the quarter-wave plate again and enters the volume hologram 521 through the imaging lens 904. At this time, since the polarization direction is rotated by 90 ° with respect to the path, this corresponds to the case of the abnormal light beam shown in FIG. Therefore, it is condensed on a specific direction, in this case, the photodetector 902, corresponding to the periodic refractive index distribution corresponding to the layer structure formed inside the volume hologram 521.

It is configured to have a periodic structure in the thickness direction as shown in Figure 18, the black diffraction condition is to be applied. This is because when light having a certain wavelength enters each layer forming a periodic structure, the light scattered in each layer causes the scattering components to become strong in a specific direction corresponding to the wavelength, the incident angle, and the pitch between the layers. do.

These are referred to as black diffraction conditions, and such conditions have a three-dimensional configuration with respect to a conventional two-dimensional diffractive optical element, and have a function of blazing (converging light in one direction). It becomes.

Therefore, the diffraction efficiency can be remarkably improved with respect to the conventional diffraction optical element, and theoretically, the efficiency of 100% is possible. In fact, even when considering the loss in the middle, the efficiency can be expected to 90% or more. On the other hand, when the hologram element shown in Fig. 40 is constituted by the diffraction optical element made of the binary as described above, the diffraction wave is diffracted up to the high order in left and right symmetry including the 0th order. As a result, the diffraction efficiency in the primary direction is at a value of 1/2 or more as a ratio with respect to the total amount of light passing through the element at a maximum of about 40%.

In the present invention, when the optical information processing apparatus is configured using the volume hologram 521, almost all of the reflected light from the optical storage medium 906 can be collected by the photodetector 902, resulting in a decrease in the light intensity. It does not cause a problem of lowering the S / N ratio. In addition, since the diffraction efficiency of the volume hologram 521 is high, there is almost no light amount returned to the semiconductor laser. Therefore, there is no problem of instability of oscillation of the laser which is a light source due to the return of the light intensity to the semiconductor laser 901.

In FIG. 18, the difference in refractive index inclined by 90 ° between the adjacent optical layers of the optical medium constituting the volume hologram 521 is the largest. However, by setting this angle arbitrarily, the refractive index difference is set from Ne to No. It is also possible to set.

It is also possible to adjust the diffraction efficiency by selecting the refractive index distribution using this, and to set the detection light intensity and pattern arbitrarily with respect to the photodetector 902.

Further, the area of the volume hologram 521 is divided into several parts, and the diffraction directions are shifted, respectively, so that an optical signal is received in another area of the photodetector 902, and the detection of various kinds of information such as focus shift and tracking shift can be efficiently performed. It is also possible to make the configuration.

In the case where the semiconductor laser 901 is used at a plurality of different wavelengths, and not only the optical information recording but also the recording is performed simultaneously, the volume hologram has a layer structure having different periodic structures, angles, and the like in accordance with the respective optical wavelengths. It is also possible to superimpose and record in 521.

(Embodiment B8-2)

In the present invention, a method of manufacturing a diffractive optical element for use in an optical information processing apparatus will be described with reference to FIG.

The outgoing light having a wavelength of about 360 nm from the Ar laser 911 is expanded to a beam having a diameter of about 30 nm to 50 nm by the beam expander 913 through an open / closed mechanical shutter 912. The beam splitter 915 is divided in two directions and irradiated at an angle corresponding to the structure of the interference height formed on the volume hologram 521 by the mirror 906. In addition, the shutter 405 is disposed in one beam of light while being split in the beam splitter 915.

Next, the manufacturing process of the cell of the volume hologram 521 will be described.

Two transparent conductive electrodes, for example, on which ITO was formed were prepared on a glass substrate. Then, these substrates are washed to remove dust, and then an alignment film made of a polymer, such as polyimide, is applied by spin coating or the like, followed by heat treatment to form an alignment film on the substrate.

Thereafter, rubbing treatment is performed in a specific direction by a roller or the like, the yarn is printed around one substrate, and beads having a diameter of about 5 µm to 20 µm are dispersed on one substrate. These two substrates were configured such that the empty cells in which the rubbing directions were paired with each other.

As an optical medium having refractive index anisotropy, a liquid crystal was used, and injection was performed on the empty cell produced here. The liquid crystal used this time has positive dielectric anisotropy. It is also possible to use those with negative dielectric anisotropy.

A photopolymerizable liquid crystal monomer, a photocrosslinkable liquid crystal polymer, and the like are included, and the liquid crystal is cured by light irradiation of a wavelength in the ultraviolet region around 360 nm, and the liquid crystal molecules have a characteristic of immobilizing. The injection was carried out in an air atmosphere at room temperature, but the injection may be performed at a high temperature of about 40 ° C to 60 ° C or in a vacuum atmosphere. The cell after the injection of liquid crystal was sealed in the vicinity of the injection port and the deaerator with a sealant to complete the liquid crystal sample.

The liquid crystal sample produced as above was set at the manufacturing position of the volume hologram 521 in the optical system shown in FIG. The shutters 912 and 405 were opened in advance and adjusted to form a superficial arc having a pitch of about 1 μm at the sample position. At this time, the condensing angle of the luminous flux by the mirror 906 is about 15 ° to 45 °, and the irradiation intensity of the Ar laser is about 50mW to 100mW.

Next, the process of forming the interference height with a laser with respect to a liquid crystal sample is demonstrated. First, the shutter 912 is closed and the liquid crystal sample is set with the shutter 405 open. Then, the shutter 912 is opened for a predetermined time, here about one minute, and then closed.

This is the first step, by which the liquid crystal sample is cured in the region of the region belonging to the high intensity of the interference height formed by the interference of the two light beams of the laser, and the liquid crystal molecules are initially aligned. The molecular axis is fixed. Since a liquid crystal having positive dielectric anisotropy is used here, initially, liquid crystal molecules are evenly oriented in a direction parallel to the glass substrate, and this state is preserved. On the other hand, in the region belonging to the dark portion of the interference height, since the light intensity is lower than that of the light, hardening of the liquid crystal molecules is hardly promoted in this first step.

Next, as a second step, an alternating electric field of about 5 (V / μm) is applied between the ITO electrode serving as the transparent conductive electrode formed inside the glass substrate of the two liquid crystal samples. By applying this electric field, the uncured liquid crystal molecules in the region belonging to the dark portion of the interference height are inclined in the direction standing perpendicular to the glass substrate. Since the inclination angle at this time is proportional to the electric field to be applied, the desired inclination angle and refractive index difference can be given by adjusting the magnitude of the electric field.

Close the shutter 405 while applying the voltage as described above, irradiate the entire surface of the volume hologram 521 with light of an even intensity distribution without forming an interference height for about 5 minutes, and include liquid crystal in the uncured dark region. Harden the whole completely.

By performing the above-mentioned first and second steps, a volume hologram 521 having a structure as shown in FIG. 18 was produced. The diffraction efficiency of this device was measured by changing the incident polarization direction using a He-Ne laser. The transmittance to normal light was around 98%, and had a high transmittance. In addition, good results were obtained in which the diffraction efficiency in the primary direction with respect to the abnormal light beam was about 90%. Therefore, the volume hologram device manufactured here has high polarization separation characteristics and diffraction efficiency, and proves to be promising as a diffraction optical element used in an information processing apparatus.

(Embodiment B8-3)

Using two opposite glass substrates, the same process as in Embodiment B8-2 was carried out from forming an alignment film thereon, and a liquid crystal sample was tested. This sample was set in the optical system shown in FIG. 42, and the exposure of the interference height was exposed as a 1st process.

Next, as a second step, a setting for applying a magnetic field to the volume hologram sample 521 shown in Fig. 42 is made in order to change the arrangement direction of the liquid crystal molecules in the region belonging to the arc of the dark portion from the initial position. It was done. Specifically, a magnetic field was formed around the liquid crystal sample by the superconducting magnet.

Since the liquid crystal has dielectric anisotropy, it is possible to change the molecular axis of the liquid crystal molecules by applying the same magnetic field as the electric field. By applying the magnetic field as described above, the liquid crystal molecules in the dark region are changed in the direction perpendicular to the glass substrate. In this state, the shutter 405 was closed in the same manner as in the embodiment B8-2, and the entire panel was cured by performing uniform light irradiation on the liquid crystal sample.

When magnetic field application is used, the liquid crystal sample is not required to form ITO or the like as a transparent conductive electrode, so that the configuration in which this process is omitted is simpler and more inexpensive production is possible. Moreover, since the influence of the reflected light by the refractive index difference in glass and an ITO interface is eliminated, a transmittance becomes high and it also improves the function as a diffraction optical element.

The diffraction efficiency with respect to the polarization direction of the volume hologram element produced in the above process was measured by the same method as the actual form B8-2. As a result, it was found that the diffraction efficiency had a performance of 90% or more, and it was possible to appropriately control the liquid crystal molecular direction even by a method by applying a magnetic field.

(Embodiment B8-4)

From the step of applying the alignment film on the glass substrate, a liquid crystal sample was produced in the same manner as in the embodiment B8-3. In Embodiment B, polyvinyl cinnamate (PVCi) was used as an oriented film, and the process of roller rubbing was abbreviate | omitted. This sample was set in the optical system in FIG. In this system, a polarizer is provided immediately after the beam expander 913, and only the linearly polarized light component of the laser beam is used.

First, as a 1st process, exposure of the area | region belonging to the list of interference heights was performed similarly to Embodiment B8-2. At this time, the interference height pattern consists only of the linearly polarized light component of the laser light. When linearly polarized light is irradiated onto a polymer film as a light source, molecules whose main chains (or side chains) are directed in the polarization direction from among randomly oriented polymers mainly absorb light and cause photoreaction, and optical anisotropy is expressed on the film. . In the polymer material or the like, the photoreaction process (photoisomerization, photopolymerization, photolysis) of the polymer can be controlled by the polarization direction of the irradiated light and the angle formed by the polymer.

Therefore, setting was made such that the alignment direction of the liquid crystal molecules became parallel to the glass substrate by controlling the polarization direction of the light of the ultraviolet region constituting the interference height.

Next, in the second process, a half-wave plate was placed immediately after the polarizer, and the polarization direction of the laser light was rotated by 90 degrees. Then, the shutter 405 was closed, and uniform light having the polarization direction in the direction orthogonal to the polarization direction was irradiated to the liquid crystal sample in the first step. In the region belonging to the dark portion, since the light of which the polarization direction is rotated by 90 ° is irradiated with respect to the light beam, the alignment direction of the liquid crystal molecules changes from the position of the first step and is fixed.

Through the above process, it is possible to form a periodic structure in which the direction of the liquid crystal molecules differs in the layer corresponding to the crest of the interference height and the dark portion. In this case, in order to align the liquid crystal molecules by light irradiation, it is possible to perform both the exposure of the interference height and the production process can be simplified. In addition, the rubbing method with a roller can be performed in a non-contact manner, to prevent the mixing of dust and the like, to establish a highly reliable manufacturing process technology, and to stably cope with mass production.

The diffraction efficiency of the volume hologram 521 produced here was evaluated in the same manner as in Embodiments B8-2 and 3. As a result, the diffraction efficiency is about 70%, and the efficiency of 50% or more of slightly decreasing diffraction efficiency is obtained, and it is evident that a diffraction optical element having a three-dimensional periodic structure is produced.

In addition, after coating PVCi as an oriented film, before assembling a cell, the process of performing light irradiation of the wavelength of the ultraviolet region which has a specific polarization direction may be introduced for the improvement of the orientation of a liquid crystal molecule.

(Embodiment B8-5)

Using the same process as in the embodiment B8-2, a test liquid crystal sample was produced. This time, the mask was masked in half of the sample and set in the optical system shown in FIG. Then, in the same manner as in the embodiment B8-2, the first and second steps were performed to produce volume holograms in the region without a mask.

Next, by changing the angle of the mirror 916 shown in FIG. 42, the beam angle of two light beams changed about 5 degrees. Then, the mask portion of the first sample was removed, and the first and second steps were repeated for this portion to produce a volume hologram.

As a result of evaluating the volume hologram element 521 produced as described above, light was diffracted in two different angular directions with respect to irradiation of abnormal light to the front surface of the element.

Moreover, each diffraction efficiency at this time is about 90%, and it turned out that the layer structure from which several area | region differed favorably can be manufactured. Applying this to the configuration of FIG. 40, since it is divided into two directions by the volume hologram element 521, signal detection is performed at once in different areas on the photodetector 902, and signal detection such as focus shift and tracking shift can be efficiently performed. I can do it.

(Example B8-6)

A liquid crystal sample was produced in the same manner as in the embodiment B8-6. This was introduced into the optical system shown in Fig. 42 and the first step was performed to expose the area belonging to the crest of the interference height. Here, the angle of the mirror 916 was changed by about 5 degrees, and the interference height of another period was formed, and the said 1st process was repeated in this state, and exposure of the area | region of the root was performed.

Next, similarly to Embodiment B8-2, the shutter 405 was closed and the volume hologram element was produced by performing the 2nd process which irradiates the volume hologram element 521 with uniform light.

The volume hologram element 521 produced as described above was evaluated. Using the abnormal light beam, the angle of the laser for diffraction efficiency measurement was set in the direction corresponding to the exposure of two interference heights, and each was measured at a different angle. The diffraction efficiency was about 75% to 80% in two cases, respectively. Although the diffraction efficiency is somewhat reduced compared to the case of forming the interference height by overlapping, it is considered that the improvement is possible even by adjusting the thickness of the liquid crystal sample thickly. On the other hand, about normal light, it had the transmittance | permeability of about 98% similar to Embodiment B8-2.

As described above, the volume hologram element 521 can be manufactured by overlapping the interference height. This is considered to be effective in an optical information processing apparatus for performing 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 apparatus by the optical medium having refractive index anisotropy and the manufacturing method thereof have been described.

As the optical medium having a refractive index anisotropy is also possible to use niobium (niobiom) lithium, KD ₂ PO _4, determination of the uniaxial having such an electro-optical effect, such as β-BaB2O4, PLZT, and further KTiPO ₄ such as biaxial the It is also possible to exert the effect by using a medium having refractive index anisotropy including optical crystals and the like.

It goes without saying that it can also be used as a write-only or read-only device.

As described above, according to the present invention, it is possible to convert the output light flux of the lamp with a large light emitter into the output light flux from a small light emitter, and thus the light condensing efficiency of the illumination optical system can be improved remarkably.

In addition, it is possible to minimize the loss of the light collection efficiency or the polarization conversion efficiency of the integrator and the polarization conversion element caused by the influence of the condensing optical system aberration due to the size of the light emitting body, and to achieve uniform and bright (projection efficiency High) image can be displayed.

In addition, according to the present invention as described above, it is possible to provide a hologram element capable of switching the incident light to diffraction / straightness and having a very small diffraction of the extraneous light incident at an oblique angle when going straight. In addition, by using the hologram element of the present invention, it is possible to realize a high-efficiency polarization separation function at low cost, and to use it to constitute highly efficient image display.

In addition, by using the hologram element of the present invention, a direct view type image display device that can be switched from time to time can be configured as necessary to display an image display having a narrow viewing angle but having a bright viewing angle and an image having a large viewing angle having a low brightness from the front.

Therefore, the present invention can be used in such fields as an image display device and is effective.

Table 1

Refractive Index Difference Δn (Ne-No) Average refractive index Ne-No / 2 Lattice Pitch (μm) Diffraction grating thickness (㎛) Incident wavelength (㎛) Black angle (°) η1 0.083 1.593 1.323 10 0.55 12 η2 0.145 1.591 1.323 10 0.55 12

Claims (122)

Has a plurality of regions with different composition of materials, The plurality of regions include at least a first region composed of a photocurable liquid crystal having a refractive index anisotropy as well as curing at a specific wavelength; By the said wavelength, it forms in the 2nd area | region which consists of non-hardened liquid crystal (it abbreviates as non-polymerizable liquid crystal hereafter), The refractive index with respect to the normal light beam and the abnormal light beam after hardening of the said photocurable liquid crystal is substantially the same as the refractive index with respect to the normal light beam and the abnormal light beam of the said non-polymerizable liquid crystal, respectively. Hologram element. The method of claim 1, And controlling the refractive index of the second region with respect to the incident light beam by controlling the switching state of the non-polymerizable liquid crystal by the voltage applied to the non-polymerizable liquid crystal. In the method of manufacturing the hologram element of claim 1, A laser beam having a wavelength at which a mixed liquid crystal formed by mixing the photocurable liquid crystal and the nonpolymerizable liquid crystal is substantially uniformly injected between two parallel flat glass substrates arranged at a specific interval and curing the photocurable liquid crystal. And a plurality of regions are formed by interfering the injected mixed liquid crystal with each other. At least the hologram element according to claim 1 or 2, Illumination means for illuminating the hologram element, And image display means for displaying an image by modulating the output luminous flux of said hologram element. The method of claim 4, wherein And the hologram element selectively changes only an exit angle of a specific polarization component among unpolarized incident light beams. The method of claim 4, wherein The hologram element has a function of diffracting a specific polarization component (hereinafter, abbreviated as first polarization component) of the incident light from the illumination means in a substantially normal direction of the image display means, and the hologram element is applied to the second region. And controlling the function by controlling the applied voltage. The method of claim 4, wherein The image display means has a function of modulating only a specific polarization component (hereinafter abbreviated as a second polarization component), and further comprising the first polarization component and the second polarization component selectively diffracted by the hologram element. An image display apparatus, wherein the direction of oscillation of the electric field vector is substantially the same. The method of claim 4, wherein And a λ / 4 wave plate and a reflecting mirror on a rear surface of the hologram element, wherein an installation angle of the reflecting mirror is at least 5 ° with respect to the hologram element. At least each pixel has a microcell structure surrounded by a cured photocurable liquid crystal, And a non-polymerizable liquid crystal in the microcell, And the refractive index with respect to the normal light after curing of the photocurable liquid crystal and the refractive index with respect to the abnormal light are substantially the same as the refractive index with respect to the normal light and the refractive index with respect to the abnormal light of the non-polymerizable liquid crystal, respectively. At least, it has polarization anisotropy with respect to the incident light beam, Usually consists of first and second holographic elements on the plate that selectively diffract only the first polarization component, An angle θ0 constituting an optical axis and an incident light beam incident on the first hologram element, An angle θ1 of which the first output light beam diffracted by the first hologram element is incident to the optical axis; The angle θ2 of the second light flux diffracted after the first output light beam is incident on the second hologram element and formed by the optical axis is expressed by the following equation. θ1-θ2 〉 20 θ0-θ2 〈15 Polarization separator, characterized in that to satisfy. In the polarization splitting device of claim 1, The polarization splitting device is a polarization splitting device comprising a holographic material sandwiched by a glass substrate. In the polarization splitting device of claim 1, And the hologram material is a UV curable liquid crystal. In the polarization splitting device of claim 1, And the hologram material is a mixture of a photopolymer having a sensitivity to a wavelength of a specific region and a liquid crystal polymer. A projection type image display apparatus comprising at least polarized image display means and illumination means for illuminating the polarized image display means, The polarization type image display means displays an image by modulating and outputting a specific polarization component among the illumination light from the illumination means incident on the polarization type image display means, The illuminating means includes at least a light emitting means, a first condensing means for condensing the output light flux of the light emitting means, the polarization splitting element, and a plurality of microlenses in a two-dimensional array. It has an integrator composed of an eye lens, The polarization splitting element is disposed between the first fly's eye lens and the first condensing means, diffracts a first polarized component among the incident light beams, outputs the second polarized light beam, and has a polarization direction orthogonal to the first polarized light component. Output as a third luminous flux with almost no diffraction of the second polarization component, Each lens of the first microlens group constituting the first fly's eye lens forms an image of the light emitting unit on a corresponding microlens of the second microlens group constituting the second fly's eye lens, And a polarization plane rotating means for rotating the polarization direction by approximately 90 ° at a position where the second light beam or the third light beam forms an image. A first and second holographic elements on a plate disposed substantially parallel to each other and selectively diffracting predetermined polarization components that are substantially the same as each other, A diffracted light beam incident on the first hologram element, diffracted by the first and second hologram elements and exiting from the second hologram element, An angle between the first and second hologram elements, transmitted through the first and second hologram elements and transmitted from the second hologram element, is greater than 0 ° and less than 15 °; and At the same time, The angle between the light flux incident on the first hologram element and the light flux incident on each hologram element at the light flux diffracted by the first and second hologram elements and the light flux diffracted by each hologram element are each 20 °. Polarization splitter, characterized in that exceeding. In the polarization splitting device of claim 1, And said first and second hologram elements comprise a hologram material disposed between a pair of glass substrates. In the polarization splitting device of claim 2, The hologram material is a polarization splitting device, characterized in that the ultraviolet curable liquid crystal is made by curing. In the polarization splitting device of claim 2, The hologram material is a polarization splitting device, characterized in that the mixture of the photopolymer and the liquid crystal polymer having a curability to the irradiation of light of a wavelength of a predetermined region is cured. Light emitting means, A polarization splitting element for varying optical paths of polarization components in different directions at the incident light flux, Condensing means for condensing the diffracted light beam and the transmitted light beam emitted from the polarization splitting means at different first and second positions, respectively; An image display apparatus comprising polarization plane rotating means for rotating a polarization direction of a polarization component incident on either of the first and second positions, The polarization separation means, A first and second holographic elements on a plate disposed substantially parallel to each other and selectively diffracting predetermined polarization components that are substantially the same as each other, A diffracted light beam incident on the first hologram element, diffracted by the first and second hologram elements and exiting from the second hologram element, The angle between the first and second hologram elements, transmitted through the first and second hologram elements and transmitted from the second hologram element, is greater than 0 degrees and less than 15 degrees. , An angle between the light flux incident on the first hologram element and the light flux incident on each hologram element at the light flux diffracted by the first and second hologram elements and the light flux diffracted by each hologram element are each greater than 20 °. Polarizing separation element, characterized in that. The method of claim 5, Each microlens constituting the first fly's eye lens has a first and a second fly's eye lens in which a plurality of microlenses are arranged, respectively, and a corresponding smile in the microlens making up the second fly's eye lens. An integrator for forming an image of the light emitting means in a lens; And said condensing means is a first fly's eye lens of said integrator. The method of claim 5, The diffraction light beam and the transmitted light beam are light beams whose polarization directions are perpendicular to each other, And said polarization plane rotating means rotates the polarization direction of the incident light beam by approximately 90 degrees. At least a diffractive optical element having a light source and refractive anisotropy and a total reflection mirror disposed adjacent thereto, The polarization component (P wave or S wave) in one direction of the light emitted from the light source passes through the diffraction optical element, is reflected by the reflection mirror, and passes through the diffraction optical element again and exits. A component (S wave or P wave) orthogonal to the outgoing light is emitted by changing the propagation direction by the diffraction action of the diffractive optical element, and the diffracted wave from the diffractive optical element and the reflected wave from the total reflection mirror And a predetermined wavefront of the diffractive optical element is formed such that the propagation direction of is substantially the same and the relative emission angle is different. With a light source, A diffraction optical element having refractive index anisotropy, A total reflection mirror disposed adjacent to this, At least a phase plate disposed in the optical path to the diffractive optical element in order to rotate the polarization direction of the reflected light from the total reflection mirror in a direction perpendicular to the polarization direction of the light at the time of exiting, A polarization component (P wave or S wave) in one direction of the light emitted from the light source passes through the diffractive optical element and is reflected by the reflecting mirror, and passes through the phase plate and the diffractive optical element and exits. A component (S wave or P wave) orthogonal to the outgoing light is emitted by changing the propagation direction by the diffraction action of the diffractive optical element, and the diffracted wave from the diffractive optical element and the reflected wave from the total reflection mirror And a predetermined wave surface of the diffractive optical element is formed so that the propagation directions of are substantially the same and become substantially parallel luminous fluxes. In the polarizing illumination device of claim 2, And a polarization direction between the diffraction wave from the diffraction optical element and the light wave reflected by the total reflection mirror and emitted. In the polarizing illumination device of claim 2, And said diffractive optical element is reflected by said total reflection mirror and generally transmits an optical wave passing through a phase plate. With a light source, A set of diffractive optical elements having refractive index anisotropy, At least a phase plate for rotating the polarization direction of the incident light wave in a right angle direction is at least a component, The light emitted from the light source is incident on one diffractive optical element, Transmitted or diffracted for each polarization component (P wave or S wave), The diffraction wave is incident on the other diffraction optical element and diffracted again and exits, In a configuration in which a phase plate is disposed in one of the optical paths of either the transmission wave or the diffraction wave of one set of diffraction optical elements, A set of diffractive optical elements is arranged so that a set of diffractive optical elements is arranged so that the light flux after being transmitted or diffracted by a set of diffractive optical elements becomes a substantially parallel light flux. In the polarizing illumination device of claim 5, The inclination angle of the pair of diffractive optical elements is 45 ° or less with respect to a plane in which the incidence surfaces of the light waves of the pair of diffractive optical elements are substantially parallel to each other and perpendicular to the optical axis of the emitted light from the light source. . In the polarizing illumination device of claim 5, And a polarization direction of substantially parallel light beams emitted from the pair of diffractive optical elements is generally the same. A diffraction optical element for transmitting or diffracting the light emitted from the light source for each polarization component (P wave or S wave), Another set of diffractive optical elements for diffraction of the diffraction wave, When the phase plate disposed in one of the optical paths of either the transmission wave or the diffraction wave of the set of diffraction optical elements is one structural unit, And a plurality of structural units comprising the pair of diffractive optical elements and a phase plate are arranged side by side adjacent to each other. In the polarizing illumination device of claim 8, And a light beam emitted from the plurality of constituent units are substantially parallel light beams, and the polarization directions generally coincide. In the polarizing illumination device of claim 8, And the phase plate has a function of rotating the polarization direction of the incident light wave in a generally perpendicular direction. In the polarizing illumination device of claim 8, Incident surfaces of the light waves of the set of diffractive optical elements forming the plurality of structural units are usually parallel to each other and And an inclination angle of the set of diffractive optical elements with respect to a plane perpendicular to the optical axis of the light emitted from the light source is 45 ° or less. The polarizing illumination device according to any one of claims 1, 2, 5, and 8, 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 the polarization component (P wave or S wave) in one direction of the incident light, This difference in refractive index causes diffraction of light And a component (S wave or P wave) that is generally orthogonal to the incident light, and has a function of preferentially going straight. In the polarizing illumination device of claim 12, And the periodic structure of the diffractive optical element is formed by the inclination of the optical axis of the optical medium having refractive index anisotropy. In the polarizing illumination device of claim 12, The diffractive optical elements comprise liquid crystals arranged in the same manner, and A photopolymerizable monomer or a photocrosslinkable liquid crystal polymer is added, A polarization illumination device, characterized in that the direction of the molecular axis of the liquid crystal is fixed to light irradiation in the ultraviolet region. The polarizing illumination device according to any one of claims 1, 2, 5, and 8, The diffractive optical element includes a structure formed by overlapping a plurality of different periodic structures. The polarizing illumination device according to any one of claims 1, 2, 5, and 8, And said diffractive optical element comprises a stacked structure of diffractive optical elements having a plurality of different periodic structures. The first lens array and the second lens paired with the said 1st lens array comprised by arrange | positioning a some lens in the polarization illuminating device in any one of Claims 1, 2, 5, and 8. And at least a combination of an array, a light valve, and a projection optical system that enlarges and projects an optical image on the light valve. The luminous flux from the light source is usually color-separated into three luminous fluxes of different wavelengths corresponding to R (red), G (green), and B (blue), The polarization illumination device according to any one of claims 1, 2, 5, and 8 is formed by using a diffraction optical element having different formation wavefronts for light beams having different wavelengths. A first lens array configured by arranging a plurality of lenses therein; A second lens array paired with the first lens array; With light valve, And a projection optical system which enlarges and projects the optical image on the light valve. With a light source, A liquid crystal element having a liquid crystal layer sandwiched between two opposing transparent insulating substrates having patterned transparent conductive electrodes on which pixels are to be formed; Diffraction optical elements arranged on both sides of the liquid crystal element, It is configured to include at least, The light emitted from the light source is incident on one diffraction optical element and diffracted Almost half of the amount of granular light to the diffractive optical element is incident on the liquid crystal element, Modulated for each pixel of the liquid crystal element, An image display apparatus according to the modulation degree, wherein image display is performed by an operation in which the propagation direction of light after passing through the other diffractive optical element is different. A liquid crystal element having a liquid crystal layer sandwiched between two opposing transparent insulating substrates having patterned transparent conductive electrodes on which pixels are to be formed; At least a mirror and a diffraction optical element disposed on one side of the liquid crystal element, Incident light to the diffractive optical element by external light is diffracted, Passing through the liquid crystal element, reflected by the mirror, and passed through the liquid crystal element again and modulated for each pixel of the liquid crystal element, An image display apparatus according to the modulation degree, wherein image display is performed by an operation in which the propagation direction of light after exiting the diffractive optical element is different. With a light source, A liquid crystal element having a liquid crystal layer sandwiched between two opposing transparent insulating substrates having patterned transparent conductive electrodes on which pixels are to be formed; A mirror disposed on one side of the liquid crystal element, Diffraction optical elements arranged on both sides of the liquid crystal element, It is configured to include at least, The light emitted from the light source is incident on one diffractive optical element and diffracted Almost half of the amount of incident light to the diffractive optical element is incident on the liquid crystal element, and is modulated for each pixel of the liquid crystal element, Image display is performed by an operation in which the propagation direction of light after passing through the other diffractive optical element differs in accordance with the modulation degree. Incident light to the diffractive optical element by external light is diffracted, Passing through the liquid crystal element, being reflected by the mirror and passing through the liquid crystal element again, is modulated for each pixel of the liquid crystal element, In a configuration in which image display is performed by an operation in which the propagation direction of light after exiting the diffractive optical element is changed according to the modulation degree, And an image display by selectively switching the light source and the external light arranged inside. In the image display apparatus according to any one of claims 1 to 3, The diffractive optical element has a periodic structure formed using an optical medium having refractive index anisotropy, and generates a refractive index distribution corresponding to the periodic structure with respect to the polarization component (P wave or S wave) in one direction of the incident light. An image display apparatus characterized by generating a diffraction of light due to a difference in refractive index, and preferentially going straight with respect to a component (S wave or P wave) which is usually orthogonal to the incident light. The image display apparatus according to claim 3 or 4, One of the diffractive optical elements has a function to diffract P waves of the polarization component of the incident light and to go straight ahead of the S waves, and the other side of the diffractive optical elements diffracts the S waves and preferentially straightens the P waves. An image display apparatus having a function. In the image display apparatus of claim 4, And the periodic structure of the diffractive optical element is formed by the inclination of the optical axis of the optical medium having refractive index anisotropy. In the image display apparatus of claim 4, The diffractive optical element is configured to include liquid crystals arranged in the same manner, and a photopolymerizable monomer or a photocrosslinkable liquid crystal polymer is added, and the direction of the molecular axis of the liquid crystal is fixed to light irradiation in an ultraviolet region. Image display device. In the image display apparatus according to any one of claims 1 to 3, And controlling the electric field applied to each pixel formed in the liquid crystal layer, wherein the incident light to each pixel is modulated. In the image display apparatus according to any one of claims 1 to 3, And the diffractive optical element includes a structure formed by superimposing a plurality of different periodic structures. In the image display apparatus according to any one of claims 1 to 3, And the diffractive optical element comprises a stacked structure of diffractive optical elements having a plurality of different periodic structures. The image display apparatus according to any one of claims 1 to 3, wherein a color filter composed of red (R), green (G), and blue (B) is formed on one side of the liquid crystal element. An image display device. 11. The image display apparatus according to any one of claims 1, 3, and 10, wherein the light emitted from the diffraction grating is usually divided in two directions, and one is for image display and the other is for illumination light. An image display apparatus and a lighting apparatus, characterized in that the configuration is used as. A liquid crystal element having a light source and a liquid crystal layer sandwiched by two opposing transparent insulating substrates having patterned transparent conductive electrodes on which pixels should be formed, and diffractive optical elements having refractive index anisotropy on one side of the liquid crystal element And a diffractive optical element having a phase plate for rotating the polarization direction of the light wave in a generally perpendicular direction and having refractive index anisotropy disposed on the other side of the liquid crystal element, wherein the light emitted from the light source is It is usually converted into the same polarization component (P wave or S wave) by the diffraction optical element and the phase plate, is incident on the liquid crystal element, modulated for each pixel of the liquid crystal element, and passes through the other diffraction optical element according to the modulation degree. An image display apparatus characterized by performing image display by an action in which the propagation direction of subsequent light is different. The image display apparatus according to any one of claims 1, 2, 3, 11, 12, and 13, at least a magnified optical system for enlarging and displaying an optical image of the image display apparatus. And a small image display device. A liquid crystal element which modulates a polarization direction of incident light according to an applied voltage; First and second pairs of diffractive optical elements disposed on both sides of the liquid crystal element and selectively diffracting a predetermined polarization component and transmitting a polarization component orthogonal to the predetermined polarization component and the polarization direction. An image display device comprising: In the image display apparatus of claim 1, The first diffraction optical element injects either the transmitted polarization component or the diffracted polarization component into the liquid crystal element among the light beams incident from the outer side, The second diffractive optical element is configured to emit a polarization component transmitted through the second diffraction optical element at a light beam emitted from the liquid crystal element and a polarization component diffracted by the diffraction optical element in different directions. An image display apparatus. In the image display apparatus of claim 2, Further provided with a light source, And the first diffractive optical element is configured to cause a polarization component transmitted through the diffractive optical element at a light beam from the light source to be incident on the liquid crystal element. In the image display apparatus of claim 2, And a light source disposed in the normal direction of the first diffractive optical element, And the first diffractive optical element is configured to cause a polarization component transmitted through the diffractive optical element at a light beam from the light source to be incident on the liquid crystal element. In the image display apparatus of claim 2, And a light source disposed in a direction inclined from a normal direction of the first diffraction optical element, And the first diffractive optical element is configured to cause the polarization component diffracted by the first diffractive optical element at the light beam from the light source to be incident on the liquid crystal element. In the image display apparatus of claim 2, Reflecting means provided at an outer side of the first diffractive optical element at a predetermined interval; And a light source for injecting a light beam into the diffraction optical means in a direction inclined from a normal line of the diffraction optical element through a distance between the first diffraction optical element and the reflecting means, The first diffractive optical element may include a polarization component diffracted by the first diffraction optical element at a light beam incident from the light source and a polarization component transmitted through the first diffraction optical element incident from the reflecting means. And an image display device, the image display device being configured to enter the light source. A liquid crystal element which modulates a polarization direction of incident light according to an applied voltage; A diffraction optical element disposed on one side of the liquid crystal element and selectively diffracting a predetermined polarization component, and transmitting a polarization component having a predetermined polarization component and a polarization direction orthogonal to each other; And reflecting means arranged on the other side of the liquid crystal element. In the image display apparatus of claim 1, The diffractive optical element has a periodic structure formed using an optical medium having refractive anisotropy, and generates a refractive index difference corresponding to the periodic structure with respect to any polarization component of P wave and S wave in incident light. An image display apparatus having a function of generating diffraction of light due to a difference in refractive index and preferentially going straight to components that are generally orthogonal to the incident light. In the image display apparatus of claim 1, One of the diffractive optical elements has a function to diffract P waves of the polarization component of the incident light and to go straight ahead of the S waves, and the other of the diffractive optical elements diffracts the S waves and preferentially straightens the P waves. An image display apparatus having a function. In the image display apparatus of claim 8, And the periodic structure of the diffractive optical element is formed by the inclination of the optical axis of the optical medium having refractive index anisotropy. In the image display apparatus of claim 8, The diffractive optical element is configured to include liquid crystals arranged in the same manner, and further, a photopolymerizable monomer or a photocrosslinkable liquid crystal polymer is added, and the direction of the molecular axis of the liquid crystal is fixed to light irradiation in an ultraviolet region. Image display device. In the image display apparatus of claim 1, And the diffractive optical element includes a structure formed by superimposing a plurality of different periodic structures. In the image display apparatus of claim 1, And the diffractive optical element comprises a stacked structure of diffractive optical elements having a plurality of different periodic structures. In the image display apparatus of claim 1, And a color filter in which red, green, and blue regions are formed on either side of the liquid crystal element. In the image display apparatus of claim 1, And magnification optical means for enlarging and displaying the display image. A liquid crystal element having a light source and a liquid crystal layer sandwiched by two opposing transparent insulating substrates having patterned transparent conductive electrodes on which pixels should be formed, and diffractive optical elements having refractive index anisotropy on one side of the liquid crystal element And a diffractive optical element having a phase plate for rotating the polarization direction of the light wave in a generally perpendicular direction and having refractive index anisotropy disposed on the other side of the liquid crystal element, wherein the light emitted from the light source is It is usually converted into the same polarization component (P wave or S wave) by the diffraction optical element and the phase plate, is incident on the liquid crystal element, modulated for each pixel of the liquid crystal element, and passes through the other diffraction optical element according to the modulation degree. An image display apparatus characterized by performing image display by an action in which the propagation direction of subsequent light is different. The polarization direction of the laser emitting the light source, the optical lens for converging the laser light emitted from the laser onto the optical storage medium, and the polarization direction of the laser light reflected by the optical storage medium with respect to the polarization direction of the light at the time of emission. Usually an optical information processing device comprising at least a component comprising: a phase plate for rotating in a perpendicular direction, a diffractive optical element disposed in an optical path of the reflected light and generating a predetermined wavefront, and a light receiving element for detecting light diffracted by the diffractive optical element A diffractive optical element for use in which the diffractive optical element is formed using an optical medium having refractive index anisotropy, and is reflected by the optical memory medium, and 1 to the total amount of laser light after passing through the diffractive optical element. Characterized in that a predetermined wave surface is formed such that the ratio of the amount of light diffracted in the direction is usually 1/2 or more. Diffraction optical element. In the diffractive optical element of claim 1, A component having a periodic structure in the thickness direction and generating a refractive index distribution corresponding to the periodic structure with respect to the polarization component in one direction of the incident light, generating diffraction of the light by the difference in refractive index, and orthogonal to the polarization component of the incident light A diffractive optical element having a function of preferentially going straight ahead. In the diffractive optical element of claim 2, A diffractive optical element having a periodic structure in a thickness direction, wherein said periodic structure is formed by the inclination of an optical axis of an optical medium having refractive index anisotropy. In the diffractive optical element of claim 2, And a photopolymerizable liquid crystal monomer or a photocrosslinkable liquid crystal polymer, wherein the direction of the molecular axis of the liquid crystal is fixed to light irradiation in the ultraviolet region. In the diffractive optical element of claim 1, And a polarization direction of the emitted light of the laser incident on the diffractive optical element is generally parallel or perpendicular to the optical axis of the optical medium having refractive index anisotropy. A diffractive optical element having a structure in which an optical medium having refractive index anisotropy is enclosed in a region sandwiched by a transparent insulating substrate having two opposing transparent conductive electrodes, and a thin film subjected to an alignment treatment made of a polymer is formed on the transparent conductive electrode. A manufacturing method comprising: interfering two-divided light in an ultraviolet wavelength range on the diffractive optical element, generating an interference height consisting of a dark portion corresponding to a periodic intensity distribution and a dark portion, and an optical axis of an optical medium in a region belonging to the dark wavelength region. And diffraction in a state in which an electric field is applied between the transparent conductive electrodes and the optical axis of the optical medium in a region belonging to the dark portion of the interference height is moved from the initial oriented direction. The optical axis direction is fixed by irradiating light to a uniform ultraviolet region on the front surface of the optical element. The manufacturing method of the diffractive optical element characterized by including a 2nd process. In the method of manufacturing a diffraction optical element of claim 6, The electric field applied to the diffractive optical element is a manufacturing method of a diffractive optical element, characterized in that the alternating electric field is generated alternately of the anode and the cathode. A method for manufacturing a diffractive optical element having a structure in which an optical medium having refractive index anisotropy is enclosed in two opposing transparent insulating substrates, and a thin film subjected to an alignment treatment made of a polymer is formed on the transparent insulating substrate. Interfering two-divided light in the ultraviolet wavelength range on the diffractive optical element, generating an interference height composed of a dark portion and a dark field corresponding to a periodic intensity distribution, and initially aligning the optical axis of the optical medium in the region belonging to the dark wavelength region. And a magnetic field applied between the first step of fixing in the direction and the transparent insulating substrate, and moving the optical axis of the optical medium in the region belonging to the dark portion of the interference height from the initially oriented direction to the front surface of the diffractive optical element. A method of manufacturing a diffractive optical element, comprising a second step of fixing an optical axis direction by performing light irradiation of a uniform ultraviolet region. A method for manufacturing a diffractive optical element having a structure in which an optical medium having refractive index anisotropy is enclosed in two opposing transparent insulating substrates, and a thin film made of a polymer is formed on the transparent insulating substrate. Interfering two-divided light of the ultraviolet wavelength region having a polarization component in one direction on the diffractive optical element, generating an interference height composed of a light and dark corresponding to a periodic intensity distribution, and optical of an area belonging to the light and light A first step of arranging and fixing an optical axis of the medium in the same direction depending on the polarization direction of the polarization component, and a uniform ultraviolet region having a polarization direction in a direction generally orthogonal to the polarization component on the front surface of the diffractive optical element And a second step of immobilizing the optical medium by moving the optical axis in an initial position and fixing the light. The manufacturing method of the diffraction optical element of any one of Claims 6, 8, and 9, And a photopolymerizable liquid crystal monomer or a photocrosslinkable liquid crystal polymer, wherein the optical medium having the refractive anisotropy is arranged in the same manner and a photopolymerizable liquid crystal monomer is added thereto. The manufacturing method of the diffraction optical element of any one of Claims 6, 8, and 9, The interference height irradiated to the diffractive optical element is a highly coherent light source consisting of a He-Cd laser or an Ar laser, and has a wavelength range of 300 nm to 400 nm. The manufacturing method of the diffraction optical element of any one of Claims 6, 8, and 9, A method of manufacturing a diffractive optical element, characterized in that the formation of a periodic structure by light irradiation to the diffractive optical element is performed a plurality of times for each divided area of the surface of the diffractive optical element. The manufacturing method of the diffraction optical element of any one of Claims 6, 8, and 9, A method of manufacturing a diffractive optical element, characterized in that the light is irradiated to the diffractive optical element a plurality of times so that another periodic structure is superposed in the diffractive optical element. At least an image display means and illumination means for illuminating the image display means, wherein the image display means displays an image by modulating and outputs illumination light from the illumination means incident on the image display means, and the illumination The means comprises at least light emitting means, first condensing means for condensing the output light flux of the light emitting means, and first wavefront converting means for converting the wavefront of the output light flux of the first condensing means, and the first wavefront conversion means. And the means is a first hologram element formed by interfering a first luminous flux that is substantially equivalent to a wavefront of an output luminous flux of said first condensing means and a second luminous flux. In the image display apparatus of claim 1, The illuminating means converts the first condensing means for condensing the output light flux of the light emitting means, the second condensing means for propagating the output light flux of the first condensing means, and the wavefront of the output light flux in the second condensing means. And a second wavefront converting means, wherein the second wavefront converting means comprises a first light beam substantially equivalent to a wavefront of the output light beam of the second condensing means, and a second hologram element formed by interfering with a third light beam. And an image display device. The image display apparatus according to claim 1 or 2, And said illuminating means comprises an integrator comprising first and second fly-eye lenses formed by arranging a plurality of lenses in a two-dimensional array. In the image display apparatus according to any one of claims 1 to 3, The image display means is a polarization display means, and the polarization display means is for displaying an image by separating polarized light deflected in a specific direction, and modulating the polarized light, usually out of the illumination light from the incident illumination means. An image display apparatus. In the image display apparatus according to any one of claims 1 to 4, And said illuminating means comprises polarization converting means for converting randomly polarized light into polarized light in a specific direction. The image display apparatus according to any one of claims 2 to 5, And the final output means of the second light collecting means is the first fly's eye lens. The image display device according to any one of claims 1 to 6, The second or third luminous flux propagates through the third luminous means the output luminous flux of the micro-luminescent body having a volume smaller than that of the luminous means of the luminous means or the luminous flux reflected by the reflector, or the luminous flux or the luminous flux thereof by the third condensing means. And an image display device substantially equivalent to the wavefront of the made luminous flux. The image display apparatus according to any one of claims 1 to 7, And the second luminous flux or the third luminous flux is a luminous flux having a substantially flat wave or a wavefront substantially equivalent to the wavefront of the luminous flux propagated by the third condensing means. The image display apparatus according to any one of claims 2 to 8, The final output means of the second light collecting means is the first fly's eye lens, the final output means of the third light collecting means is a third fly's eye lens, and the third fly's eye lens and the second fly's eye lens are paired. And an integrator. The image display apparatus according to any one of claims 1 to 9, And the reflecting mirror is a rotating object mirror, an ellipsoid mirror or a spherical mirror. The image display apparatus according to any one of claims 1 to 10, The polarization converting element includes at least polarization separation means and polarization plane rotating means, and further comprises a polarization plane on one side of the polarization planes which are generally orthogonal to each other separated by the polarization separation means, and the polarization plane rotation means is weak. An image display apparatus, characterized in that the configuration to rotate 90 °. The hologram element is manufactured by storing, in a hologram material, an interference height formed by interfering two beams of a reference light beam generated by the reference light beam generating means and an object light beam generated by the object light beam generating means, and storing one side of the two-segmented laser light. The reference beam is generated by incidence into a reference beam generating means, and the other side of the divided laser light is incident on the object collision generating means to generate the object beam. In the method of manufacturing the hologram element of claim 12, The reference beam generating means includes at least a reflector and at least a small first reflector settled at a predetermined position, and enters one of the two-divided laser beams into one or a plurality of transmission holes provided in the reflector. And illuminating and using either or both of the reflected or scattered light beams at the first reflector and the light beams that reflects the reflected or scattered light beams again at the reflector as the reference light beams. In the image display apparatus of claim 12, The object light beam generating means includes at least a reflector and a second reflector that is held at a predetermined position, and the laser beam is incident on one or a plurality of transmission holes provided in the reflector to illuminate the second reflector, and the second reflector A method of manufacturing a hologram element, characterized in that any one or both of the reflected or scattered light beam at and the light beam reflected back from the reflector or scattered light beam at the reflecting mirror are the object light beams. A method of manufacturing a hologram element, characterized in that it is substantially the same as the shape of the light emitting body of the light emitting means used in the image display apparatus. In the method of manufacturing the hologram element of any one of claims 12 to 14, The size of the second reflector is reduced or enlarged for a plurality of times to generate different object beams over a plurality of times, and the plurality of object beams and the reference beams are interfered with to multi-record on the hologram material. Method of manufacturing hologram element. In the method of manufacturing the hologram element of claim 12, And said object beam generating means is a diverging beam generating means for outputting an incident laser beam within a specific solid angle. In the method of manufacturing the hologram element of any one of claims 12, 13, 16, And the output luminous flux of said divergent luminous flux generating means is substantially the same as the luminous flux incident on the holographic element in said image display apparatus. In the method for manufacturing the hologram element of any one of claims 12 to 17, And either or both of the divergent luminous flux generating means and the object luminous flux generating means comprise one or a plurality of condensing lenses, and either or both of the integrators. In the method of manufacturing the hologram element of any one of claims 12 to 18, Wherein either or both of the reference beam generating means and the object beam generating means are holograms in which the reference beam or the object beam is recorded. In the method of manufacturing the hologram element of any one of claims 12 to 19, The reference beam and the object beam are generated using a plurality of laser beams of different wavelengths, and a plurality of two-beam interference heights formed by different wavelengths are recorded in the hologram material in a multi-layer manufacturing method. . A hologram element created by interfering an object light and a reference light, wherein the object light is a substantially parallel light beam (hereinafter, abbreviated as object light beam), and lighting means for condensing and propagating a first light beam emitted from the light emitting means. A hologram element characterized in that it is a luminous flux having a wavefront almost equivalent to the output luminous flux in (hereinafter, referred to as a reference luminous flux). The method of claim 1, The illuminating means comprises: a first fly-eye lens comprising at least two light condensing means for condensing the first light beam and a plurality of lenses for propagating a second light beam condensed by the condensing means in a two-dimensional array; A hologram element comprising an integrator incorporating two fly-eye lenses. The method according to claim 1 or 2, The illuminating means includes polarization splitting means for separating the incident light beam into components in which the polarization planes are orthogonal to each other, and polarization plane rotating means for rotating the polarization plane of one of the separated polarization components by almost 90 degrees. Hologram element characterized in that. The method according to any one of claims 1 to 3, The hologram element is a hologram element, characterized in that the reflection mirror is provided on the back side after the interference height is created. The method according to any one of claims 1 to 4, The reflection mirror is a hologram element, characterized in that for selectively reflecting the light flux of a specific wavelength band. At least the hologram element, the illuminating means for illuminating the hologram element, and image display means for displaying an image by modulating the output light flux of the hologram element, wherein the image display means corresponds to each pixel. And a microlens, the microlens having a function of converging the incident luminous flux into an opening portion of the pixel. The method of claim 6, The illuminating means includes color separation means for separating the white incident light beam into three primary colors having inherent wavelength bands, and is made of the object light beam and the reference light beam having a wavelength included in a wavelength band of a specific primary color among the three primary colors. And the output light beam of said hologram element is an incident light beam of said image display means for displaying an image signal of a corresponding primary color. The method according to claim 6 or 7, The color separation means is a dichroic mirror that selectively reflects three primary colors of a specific wavelength band, and a wavelength that the dichroic mirror corresponding to the light incidence side of each dichroic mirror selectively reflects. And the hologram element formed by an object light beam and a reference light beam having a wavelength included in a band. At least the hologram element, the illuminating means for illuminating the hologram element, and image display means for displaying an image by modulating the output luminous flux of the hologram element, wherein the image display means corresponds in three primary colors; An image display device comprising: a pixel structure comprising three pixels for displaying only image signals of primary colors; and an optical path converting means corresponding to one pixel structure. The method of claim 9, The illumination means includes at least color separation means, and the color separation means is a dichroic mirror for selectively reflecting three primary colors of a specific wavelength band, and corresponding to the light incidence side of each dichroic mirror. The hologram element formed by the object light beam and the reference light beam of the wavelength included in the wavelength band selectively reflected by the dichroic mirror is disposed, and the inclination angle of each dichroic mirror with respect to the optical axis of the illumination optical system is respectively set. By varying the angle of incidence to the image display means every three primary colors, the optical path converting means formed on the image display means corresponds to the primary colors corresponding to the primary colors incident in different directions by the hologram element and the dichroic mirror. Characterized in that it has a function of focusing on the target part of each pixel that displays only the image signal of An image display device. The method according to claim 9 or 10, And the optical path changing means is any one of a microlens array, a diffractive optical element and a cylindrical lens. A diffractive optical element comprising a plurality of micro-regions, wherein the output light flux of the micro-regions is a light beam which overlaps each other generally on a plane crossing the normal direction of the diffraction optical element at a predetermined angle. In the diffractive optical element of claim 1, The diffraction optical element is a hologram composed of a plurality of minute regions created by interfering an object light and a reference light, and the object light of the plurality of minute regions is generally mutually on a plane crossing the normal direction of the hologram at a predetermined angle. A diffractive optical element, characterized in that a light beam to polymerize. The diffractive optical element of claim 1 or 2, Diffraction optical element, characterized in that the shape in which the object light of each of the micro-regions usually polymerize with each other on the plane. In the diffractive optical element of claim 1, And the reference light is a substantially parallel light beam incident on the hologram at a predetermined angle. In the diffractive optical element of claim 1, And the reference light is a converging light that is generally converged to one point on an optical axis intersecting at a predetermined angle with respect to the hologram. At least a diffraction optical element, illumination means for illuminating the diffraction optical element, and image display means for displaying an image by modulating the output light flux of the diffraction optical element, and the output light flux of the diffraction optical element Is a quadrangle which is usually polymerized with each other on the image display means, and the shape in which the output light fluxes are usually polymerized with each other is substantially the same size as the image display means of the image display means. The method of claim 6, And said image display means comprises a microlens corresponding to each pixel, and said microlens has a function of converging the incident luminous flux into an opening portion of the pixel. The method according to claim 6 or 7, The normal line of the diffractive optical element and the optical axis of the illuminating means are not parallel, and the area where the output light flux from the illuminating means illuminates the diffractive optical element is almost elliptical shape, the major axis direction of the elliptical shape, and the image display. The long side direction of the image display area of the means is generally coincident. The method according to any one of claims 6 to 8, And said illuminating means has polarization separation means and polarization plane rotating means having a function of matching the polarization direction of the light beam that is unpolarized to a specific direction.