JP4512431B2 - Image display device - Google Patents

Description

  The present invention relates to an image display device.

In an image display apparatus (for example, a projector apparatus) using a spatial light modulation element having an array of a large number of pixels, an increase in the number of pixels and an improvement in image quality are problems. Regarding the increase in the number of pixels, if the display area of the spatial light modulator is constant, the number of pixels increases if the size of the pixels is made physically small. However, a pixel including an electric circuit is manufactured using a semiconductor manufacturing technique, and the minimum size depends on the semiconductor manufacturing technique at that time.
On the other hand, there is a technique in which a micro optical element such as a micro lens is disposed to face a pixel and the pixel is optically reduced by using a condensing function of the lens. This has the advantage of being optically small even if the physical pixel size is large. However, the image quality is deteriorated by using the lens. Further, the cost of the spatial light modulator increases as the number of pixels increases.

Thus, there is a technique for increasing the apparent number of pixels by periodically shifting the optical path of light emitted from the spatial light modulation element (for example, by deflecting light) with respect to the above method.
For example, Patent Document 1 discloses a technique for optically reducing the pixels of a spatial light modulation element using a microlens, deflecting the emitted light, increasing the number of pixels, and increasing the definition of an image. . However, according to this technique, since a microlens is used and the microlens array is disposed so as to face the pixel array of the reflective spatial light modulator, the aberration of the microlens increases and the image quality is degraded. Further, when the pixel image is reduced by the microlens, the F value of the illumination system decreases accordingly. That is, in order to improve the light utilization efficiency of the optical system without light loss due to vignetting or the like, the F value of the projection lens must be reduced, and a projection lens with a small F value leads to an increase in cost. For this reason, the development of an optical system that reduces pixels without using a microlens has been a problem.

  Therefore, Patent Document 2, Patent Document 3, and Patent Document 4 disclose technologies related to an optical deflection element mainly using liquid crystal. In this method, the spatial light modulation element is driven at a high speed, and the light is deflected at a high speed by the light deflection element. This makes it possible to apparently increase the number of pixels on the screen. Here, it is apparent that the number of pixels appears to increase due to an afterimage of human eyes. If such an optical deflection element is used, deflection control can be performed with high accuracy, such as about 5 μm, which is half that of a pixel size of about 10 μm.

  By the way, for example, Non-Patent Document 1 discloses a technique for controlling light using an element having a fine structure having a period smaller than the wavelength used. This is to produce a fine periodic structure below the wavelength in optical materials and semiconductor materials by manufacturing techniques such as photolithography, vacuum deposition, sputtering, and dry etching. A prevention element or the like can be produced. These functions are manifested by structural birefringence due to a fine structure.

  Furthermore, in Patent Document 5, as shown in FIG. 8, structural birefringent bodies 81 and 84 having regions in which the extending directions of the light reflectors 85 and 86 are different are provided in one pixel as the structural birefringent body. A technique is disclosed in which both the polarization action and the liquid crystal alignment action of the structural birefringent body are used to make a multi-domain, thereby achieving high contrast of the liquid crystal display device. Here, the structural birefringent body is manufactured on the substrate of the liquid crystal display device, and the regulation is such that the alignment direction of the liquid crystal molecules and the extending direction of the structural birefringent body are aligned.

  Furthermore, for example, Non-Patent Document 2 discloses a technique of using a multilayer film in which two different types of thin films are alternately stacked as a polarization separation element. This element separates linearly polarized light incident at the same position and orthogonal to each other and emits the light from different positions. This element is characterized in that the polarization separation angle can be made larger than that of a conventional birefringent plate using minerals. On the other hand, when linearly polarized light orthogonal to each other is incident from different positions, the positions can be matched and emitted.

JP-A-2003-248189 JP 2003-057689 A JP 2003-280041 A Japanese Patent Laid-Open No. 2003-090991 JP 2003-75851 A Hisao Kikuta and Koichi Iwata, “Optical control by a grating structure finer than the wavelength”, Optics, Vol. 27, No. 1 (1998), 12-17 Kazuo Shiraishi, “Laminated Deflection Separator with Large Separation Angle”, Optics, Vol. 29, No. 12 (2000), 755-760

The first object of the present invention is to provide a high-light utilization efficiency, a high number of pixels, and a high-definition image display device that avoids the above-described disadvantages in the case of using pixel reduction means using micro optical elements such as a microlens array. That is.
In addition to the first problem, a second problem of the present invention is to provide an image display device that can be miniaturized.
Furthermore, a third problem of the present invention is to provide an image display device that can be particularly downsized in addition to the second problem.
A fourth problem of the present invention is to provide a low-cost image display device in addition to the third problem.
Furthermore, a fifth problem of the present invention is to provide an image display device with high image quality in addition to the fourth problem.
Furthermore, a sixth problem of the present invention is to provide an image display apparatus that can deflect light with a simple mechanism and is advantageous for downsizing of the apparatus in addition to the fifth problem.
Furthermore, a seventh problem of the present invention is to provide an image display device that is advantageous for increasing the speed of light deflection and reducing the size of the device in addition to the sixth problem.

As means for solving the above-described problems, the present invention adopts the following configuration.
First image display apparatus of the configuration of the invention is at least a light source and a spatial light modulator and emits the modulated light from the light source, p-polarized light of the same percentage of light emitted from the spatial light modulator and emits the separated into s-polarized light and the polarizing element, a first polarization separating element for separating the p-polarized light and s-polarized light emitted from the polarizing element in two directions, p separated by the first polarization separating element Two reflecting elements that respectively reflect polarized light and s-polarized light, a second polarization separation element that emits s + p-polarized polarized light with the paths of p-polarized light and s-polarized light reflected by the reflecting elements in the same direction, a light deflector for deflecting the optical path of the emitted polarized light from the second polarizing beam splitter, and a projection lens for projecting the polarized light from the light deflecting element, the polarizing element of the spatial light modulator constant regions of the basic units of the same size as the size of the pixel In this case, a structural birefringent body having a periodic groove-like structure which is not larger than the pixel size and a flat portion is formed in the basic unit, and the basic unit is used as the number of pixels of the spatial light modulator. Are arranged so that the p-polarized light emitted from the spatial light modulation element is converted into s-polarized light, and a flat portion that transmits the p-polarized light emitted from the spatial light modulation element as it is. It is the structure arranged by turns (Claim 1).

Second image display apparatus of the configuration of the present invention, at least a light source and a spatial light modulator and emits the modulated light from the light source, p-polarized light of the same percentage of light emitted from the spatial light modulator and emits the separated into s-polarized light and the polarizing element, the birefringent element for emitting as a path of p-polarized light and s-polarized light emitted from the polarization element in the same direction p + s polarized light polarized light, emitted from the birefringent element has been a light deflector for deflecting the optical path of the polarized light, and a projection lens for projecting the polarized light from the light deflecting element, the polarizing element is the same size as the pixels of the spatial light modulator When the basic unit region is defined, a structural birefringent body having a periodic groove-like structure that is not larger than the pixel size and a flat portion is formed in the basic unit, and the basic unit is When arranged so as to correspond to the number of pixels of the spatial light modulator, A structural birefringence body to convert the p-polarized light emitted from the spatial light modulation element into s-polarized light, that a flat portion which is transmitted through the p-polarized light emitted from the spatial light modulator is an array configurations alternately (Claim 2).
According to a third aspect of the present invention, in the image display device having the second structure, the birefringent element is a laminated type.

According to a fourth aspect of the present invention, there is provided the image display device according to any one of the first to third configurations, wherein the spatial light modulation element is a transmission type. .
According to a fifth aspect of the image display device of the present invention, in the image display device according to any one of the first to third aspects, the spatial light modulation element is a reflective type. Item 5).

An image display device having a sixth configuration according to the present invention is the image display device having any one of the first to fifth configurations, wherein the light deflection element has a mechanical drive mechanism. 6).
According to a seventh aspect of the present invention, in the image display device having any one of the first to fifth configurations, the light deflection element uses a liquid crystal. .

  According to the first configuration of the present invention, since a polarizing element in which structural birefringent bodies having a pixel size or less are periodically arranged is used for pixel reduction, the light utilization efficiency is high, and the number of pixels is increased by light deflection. As a result, a high-definition image display device can be realized.

According to the second configuration of the present invention, in addition to the same effect as described above, the optical path length can be shortened and the apparatus can be miniaturized by using a birefringent plate instead of the polarization separation element and the reflection element. An image display device can be realized.
Further, according to the third configuration of the present invention, in addition to the above-described effect, by using a multilayer birefringent plate as the birefringent plate, the optical path length can be further shortened, and the apparatus can be further downsized. A display device can be realized.

According to the fourth configuration of the present invention, in addition to the effects of the first or second configuration, it is possible to realize an image display device capable of reducing the cost by using a transmissive spatial light modulation element.
According to the fifth configuration of the present invention, in addition to the effects of the first or second configuration, a high-quality image display apparatus can be realized by using a reflective spatial light modulation element.

According to the sixth configuration of the present invention, since a mechanical system is used for the optical deflection element, it is possible to realize an image display apparatus that has a simple mechanism and can be miniaturized.
Further, according to the seventh configuration of the present invention, since the liquid crystal is used for the light deflecting element, the device can be miniaturized and an image display device capable of high-speed light deflection can be realized.

  Hereinafter, the best mode for carrying out the present invention will be described in detail based on the embodiments shown in the drawings.

[Example 1]
First, an embodiment of an image display device corresponding to the first and fourth configurations will be shown. An example of the optical system of this image display apparatus is schematically shown in FIG. This optical system includes a light source 1, a spatial light modulation element 2, a polarization element 3, polarization separation elements 4 and 7, reflection elements 5 and 6, and a projection lens 10. These are only basic configurations. Other than this, for example, an optical element such as a fly-eye lens or a condenser lens is inserted between the light source 1 and the transmissive spatial light modulator 2. In this example, the spatial light modulation element 2 is a transmission type. The transmissive spatial light modulation element is widely used in projector apparatuses, and has advantages such as the establishment of manufacturing technology, and can reduce costs. The polarization separation elements 4 and 7 are polarization beam splitters (PBS), and the reflection elements 5 and 6 are prisms. In addition, a mirror may be used instead of the prism for the reflective element.

  The polarizing element 3 is a structure in which structural birefringent bodies having a size equal to or smaller than the size of the pixels of the spatial light modulator 2 are periodically arranged, and has structural birefringence. A configuration example of the polarizing element 3 is schematically shown in FIGS. 2 (a), (b), and (c). FIG. 2A shows a part 31 of the polarizing element 3 in an enlarged manner, in which basic units 32 including structural birefringent bodies (referred to as “called”) are arranged in 8 × 8. . The structural birefringent body is a half region indicated by black in the basic unit 32. The arrangement is actually the same as the number of pixels of the spatial light modulator 2, for example, the number of X27 standard is 1027 × 768. Here, the optical axis is perpendicular to the paper surface. Linearly polarized light 82 emitted from the spatial light modulator 2 is incident on this element. The size of the basic unit 32 is the same as the size of one pixel (square pixel) 33 of the spatial light modulator. At present, the size of one pixel is around 10 μm. Further, in the basic unit 32, the region shown in white is flat. 2B shows an enlarged view of the basic unit 32, and FIG. 2C shows a cross section along the straight line 36. FIG. 2C shows a structure in which a basic groove 32 has a periodic groove-like structure (structural birefringent body) 34 and a flat portion 35. The period (pitch) of the groove-like structure (structural birefringent body) 34 is a pitch indicated by reference numeral 37 in the drawing, and is smaller than the wavelength used for the image display device. For example, the period (pitch) 37 is a value around 100 nm. The substrate is an optical material such as quartz glass, and the groove may be filled with a high refractive index member.

  Such an element having a fine structure is known to function as a wave plate, and the delay phase difference is determined by the pitch and the depth of the groove. This is designed according to the wavelength used. By using such a polarizing element 3, it is possible to control the polarization with the size of the pixel and for each pixel. In FIG. 1, the spatial light modulation element 2 and the polarization element 3 are illustrated separately, but the above structure may be formed on the inner surface side of the emission side substrate of the spatial light modulation element 2 to provide the function of the polarization element. Good. Hereinafter, this polarizing element will be described as a λ / 2 plate (1/2 wavelength plate).

  In FIG. 1, linearly polarized light (p-polarized light) emitted from the spatial light modulation element 2 enters the polarizing element 3, and p-polarized light that passes through the flat region 35 described in FIG. The p-polarized light emitted and transmitted through the structural birefringent body 34 is converted into s-polarized light and emitted. In the transmissive spatial light modulation element 2 of FIG. 1, only four pixels are shown, and in accordance with this, the polarizing element 3 shows four basic units. At the time of emission from the polarizing element 3, the ratio of p-polarized light and s-polarized light is 1: 1, and half of the light transmitting information of one pixel is p-polarized and the other half is s-polarized light. It is. In the conventional spatial light modulation element, all the light transmitting information of one pixel has the same polarization. The p-polarized light and s-polarized light enter the PBS 4 after exiting the polarizing element 3. At this time, the positions where the p-polarized light and the s-polarized light are incident on the PBS 4 are different. After entering the PBS 4, the p-polarized light travels straight, the s-polarized light is reflected and changes its path. Subsequently, both p-polarized light and s-polarized light are incident on the prisms 5 and 6. Both polarized lights are reflected by the prisms 5 and 6 to change their courses and are emitted from the prisms 5 and 6. Next, both the p-polarized light and the s-polarized light are incident on the PBS 7, the s-polarized light is reflected to change the course, and the p-polarized light travels straight and is emitted from the PBS 7. The s and p polarized light emitted from the PBS 7 can take two optical paths (a chain line and a dotted line in FIG. 1) by the light deflecting element 52 (effect of light deflection). The light deflecting element 52 is a flat translucent member, for example, a glass flat plate. If the glass plate is perpendicular to the incident light as shown in FIG. 9A, the light goes straight, but as shown in FIG. 9B, the light is refracted by tilting the glass plate. Light deflection is possible. If there is no light deflecting element, in FIG. 1, there is an interval of half the size of the pixel between the plurality of s + p polarized light beams emitted from the PBS 7. (Not shown). The image projected on the screen at this time becomes an image 55 periodically spaced as shown in FIG. 6A (here, the spatial light modulator is in a state where all pixels are lit (all white). ) Although the pixels are reduced, the number of pixels is small. This is shifted by half the size of the pixel by the light deflecting element 52 to obtain an image 56 having twice the number of pixels without a gap as shown in FIG.

  Here, a gap 1000 is provided between the prism 5 and the PBS 7. This gap 1000 is half the size of the pixel. In this way, the p-polarized light and the s-polarized light emitted from the PBS 7 are emitted from the same position on the outgoing surface of the PBS 7 (s + p in the figure). That is, p-polarized light and s-polarized light having information of one pixel incident at different positions overlap and exit at the same position. Here, considering the size of one pixel, the area is halved due to this overlap. This means that the pixels are optically reduced (effect of pixel reduction, high definition). Further, in terms of light intensity, the p-polarized light of 1/2 and the s-polarized light of 1/2 overlap each other. Therefore, there is no light loss except for absorption by the optical member, and high light utilization efficiency is possible.

  In the case of pixel reduction using a conventional microlens or the like, there is a problem in that the image quality is deteriorated due to lens aberration, the light use efficiency is reduced, and the F value is reduced by reducing the pixel, resulting in a decrease in light use efficiency. However, since no lens is used in the present invention, there is no aberration, and there is no deterioration in image quality and light utilization efficiency. Further, since the pixels are reduced by dividing and deflecting rather than condensing, the F value does not change, and there is no disadvantage that the F value becomes small.

  In addition, as shown in this embodiment, two PBSs and two prisms are used in order to make the optical path difference between p-polarized light and s-polarized light the same except for the intentionally provided interval 1000. There is no problem even if the configuration is other than this as long as some image deterioration is allowed.

[Example 2]
In the description (FIG.) Of the first embodiment, the input / output light is described as parallel light. However, in reality, there is an illumination angle, and the skew light among the light rays incident on the PBS 4 does not become a desired linearly polarized light. In such a case, undesired polarized light may be cut using a cleaner polarizer or the like.
Further, the interval 1000 between the PBS 7 and the prism 5 is 5 μm, which is half that of a square pixel having a side of 10 μm, for example (when the gap is air). In order to ensure this accuracy, bonding may be performed using, for example, an adhesive such as an ultraviolet curable resin, as used in existing optical technology. At this time, the interval may be 5 μm or less depending on the refractive index of the adhesive.

[Example 3]
Next, an embodiment corresponding to the sixth configuration will be described. In the configuration of the first embodiment shown in FIG. 1, the pixel reduction and the light deflection are performed separately, and the light path becomes long because the light deflection element is inserted in the light path, but the pixel reduction and the light deflection are performed simultaneously. An example of a short optical path is shown below.

  FIG. 5 is a diagram showing an example of an optical deflection element having a mechanical drive mechanism. This is a stage 51 on which an optical system composed of the two PBSs 4 and 7 and the two prisms 5 and 6 described above is mounted on a stage 51. Is oscillated left and right (in the direction of the arrows 53 and 54), thereby providing the function of the light deflection element 52. If a piezo element is used as a vibrating element, it can be moved at high speed. This is simple as a drive mechanism, and a part of the optical system is moved on the stage, so that an element is not added to the optical system and the optical path is not lengthened. For this reason, the apparatus can be miniaturized. In addition, the amount of vibration of the piezo element can be changed depending on the applied voltage. This amount is, for example, 5 μm, which is half that of a square pixel having a side of 10 μm, and is adjusted by the material used and the applied voltage. Further, since it is a piezo element, vibration of 1 μm or less is possible, and the accuracy of light deflection can be made extremely high.

[Example 4]
Next, FIG. 3 shows an embodiment of the image display apparatus having the first and fifth configurations. This is an example when a reflection type is used for the spatial light modulation element. Since the reflective spatial light modulator 40 can be provided with an electric circuit under the pixel (reflecting electrode), the usable area of the pixel can be made larger than that of the transmissive spatial light modulator (improvement of the aperture ratio). ). For this reason, a high-quality image is possible. 3 shows only the front side of the image display device. In FIG. 3, reference numeral 38 denotes a light source, 39 denotes a polarization beam splitter (PBS), 40 denotes a reflective spatial light modulator, 41 denotes a field lens, and 42 denotes An intermediate image 43 is a polarizing element. Here, the PBS 39 is provided separately from the polarization separation elements 4 and 7 shown in FIG. The optical system after the polarizing element 43 is the same as the optical system shown in FIG. Further, only the basic configuration is shown, and other optical elements are also inserted. The configuration of the polarizing element 43 is the same as that of the polarizing element shown in FIG.

  White light emitted from the light source 38 passes through a uniform illumination optical system and a polarization conversion optical system (not shown) between the light source 38 and the PBS 39 and enters the PBS 39 as linearly polarized light (referred to as s-polarized light). The light enters the light modulation element 40 (only four pixels are drawn). The polarized light modulated and emitted by the reflective spatial light modulator 40 goes straight through the PBS 39 in the case of p-polarized light, and returns to the light source 38 side in the case of s-polarized light. An intermediate image 42 is formed by the field lens 41 using this p-polarized light. At this time, the magnification of the intermediate image 42 is desirably equal, and the field lens 41 is desirably bilateral telecentric. A polarizing element 43 is installed at the position of the intermediate image 42 (although it is drawn apart for distinction in the figure, it is assumed that it coincides with the position of the intermediate image 42). Thereafter, pixel reduction and light polarization are the same as those in the above embodiment, and pixel reduction and the number of pixels can be increased.

[Example 5]
Next, an embodiment of the image display device having the second and seventh configurations is shown in FIG. In FIG. 4A, reference numeral 44 denotes a light source, 45 denotes a transmissive spatial light modulation element, 46 denotes a polarization element, 47 denotes a birefringence element, 48 and 50 denote light deflection elements, and 49 denotes a λ / 2 plate. Although an optical system after the light deflection element 50 is not shown, it is assumed that there is a projection lens and a screen. The configurations and operations of the transmissive spatial light modulation element 45 and the polarization element 46 are the same as the configurations and operations of the transmissive spatial light modulation element 2 and the polarization element 3 described in the first embodiment. Omitted.

  A diagram illustrating the function of the birefringent element 47 is shown in FIG. FIG. 4B shows an example in which a birefringent plate 500 is used as the birefringent element 47, and polarized light separated into p-polarized light and s-polarized light by the polarizing element 46 enters the birefringent plate 500. When they pass through the birefringent plate 500, the s-polarized light is deflected and the p-polarized light goes straight and exits from the same position (p + s). Between a plurality of p + s (different pixels), there is an interval that is half the size of the pixel. At this time, the thickness of the birefringent plate 500 is designed according to the wavelength used and the polarization separation angle of the birefringent plate.

  Next, FIGS. 4C and 4D show an example of the operation when liquid crystal is used for the optical deflection elements 48 and 50. In this example, the optical deflection elements 481 (482), 482 using the liquid crystal are shown. 501 (502) is used to deflect the p + s polarized light, fill the interval, and display the image 56 as shown in FIG. 6B. Two optical deflection elements using liquid crystal are used (first optical deflection element 481 (482) and second optical deflection element 501 (502)), and a λ / 2 plate 491 (492) is placed between them. When both of these two light deflecting elements are off (in the case of the light deflecting elements 481 and 501 in FIG. 4C), the p + s polarized light travels straight through the first light deflector, and p is set by the λ / 2 plate 491. Although s becomes p in s, the second light deflection element also goes straight. That is, the incident position and the emission position do not change. On the other hand, when the two light deflection elements are both on (in the case of the light deflection elements 482 and 502 in FIG. 4D), the p + s polarized light is deflected.

  Here, in the case of FIG. 4D, the optical deflection element deflects only s (or p). In the first light deflection element 482, the p-polarized light goes straight and the s-polarized light is deflected, and the λ / 2 plate 492 converts the p-polarized light into s-polarized light and the s-polarized light into p-polarized light. In the second light deflection element 502, the s-polarized light is deflected and the p-polarized light goes straight. Therefore, the emission position is shifted from the incident position. The light deflecting elements 48 and 50 using a birefringent plate or liquid crystal are thinner than the optical elements such as the PBSs 4 and 7 and the prisms 5 and 6 shown in FIG. Can be realized. The liquid crystal material of the optical deflection element is a twisted nematic type, a vertical alignment type, or the like. When the vertical alignment type is used, higher-speed deflection is possible.

[Example 6]
Next, an embodiment of the image display device having the third configuration will be described. The configuration of the image display apparatus is the same as that of FIG. 4, but in this embodiment, a multilayer birefringent element is used as the birefringent element 47. Here, FIG. 7 is a schematic cross-sectional view showing an example of a laminated birefringent element. This is a structure in which high refractive index members 601 and low refractive index members 602 are alternately stacked. The function with respect to the polarized light is the same as that of the birefringent plate 500 using the mineral or the like described in FIG. However, the laminated type has an advantage that the polarization separation angle can be increased. Thereby, even when p-polarized light and s-polarized light are deflected, the thickness of the element can be made thinner than that of a normal mineral birefringent plate. This further reduces the size of the device.

The embodiments of the present invention have been described above. In the above examples, the description has been made assuming that the pixel size is reduced to ½ and the number of pixels is increased by a factor of two. However, the pixel reduction is not limited to 1/2 and the increase in the number of pixels is not limited to twice.
In order to further reduce the pixels, it is necessary to make the structural birefringence smaller. However, if the current semiconductor manufacturing technology is used, it can be manufactured without any problem.
Further, it is necessary to increase the speed of driving (switching between on and off) of the spatial light modulator, and this speed is increased in proportion to the increase in the number of pixels. Most of the current spatial light modulators use twisted nematic liquid crystal, but this problem can be solved by replacing it with a device that can be driven at high speed, such as vertically aligned liquid crystal.

  As described above, according to the present invention, since a structural birefringent body having a pixel size or less is used for pixel reduction, the light utilization efficiency is high, and further, the number of pixels is increased by deflecting light. A high-quality image display device can be realized. Therefore, the present invention can be used for a projector apparatus that displays a high-definition and high-quality image.

It is a figure which shows one Example of this invention, Comprising: It is a figure which shows typically an example of the optical system of an image display apparatus. It is a figure which shows typically the structural example of the polarizing element used for the image display apparatus shown in FIG. It is a figure which shows another Example of this invention, Comprising: It is a figure which shows typically a part of optical system of an image display apparatus. It is a figure which shows another Example of this invention, Comprising: It is explanatory drawing of a structure and operation | movement of the optical system of an image display apparatus. It is a figure which shows an example of the optical deflection | deviation element which has a mechanical drive mechanism. It is a figure which shows the example of the image projected on the screen by the image display apparatus which concerns on this invention, (a) is a figure which shows the example of the image before performing a pixel shift, (b) is when a pixel shift is performed It is a figure which shows the example of these images. It is a schematic sectional drawing which shows an example of a lamination type birefringent element. It is a figure which shows an example of a prior art, Comprising: It is a figure which shows the example of the structure birefringent body of 1 pixel of a liquid crystal display device. It is explanatory drawing of a structure and operation | movement of the optical deflection | deviation element which consists of a glass flat plate.

Explanation of symbols

1, 38, 44: Light source 2, 45: Transmission type spatial light modulator 3, 43, 46: Polarizing element 4, 7: Polarization separating element (polarizing beam splitter (PBS))
5, 6: Reflective element (prism)
10: Projection lens 34: Structural birefringence 39: Polarization beam splitter (PBS)
40: reflection type spatial light modulation element 41: field lens 42: intermediate image 47: birefringence element 48, 50: light deflection element 49: λ / 2 plate 52: light deflection element

Claims (7)

At least a light source, a spatial light modulation element that emits modulated light from the light source, a polarizing element and emits the separated light emitted from the spatial light modulation element into p-polarized light and s-polarized light of the same rate, A first polarization separation element that separates the p-polarized light and the s-polarized light emitted from the polarization element in two directions, and two reflection elements that respectively reflect the p-polarization and the s-polarization separated by the first polarization separation element ; , A second polarization separation element that emits s + p polarization polarized light with the paths of p-polarized light and s-polarized light reflected by each reflective element in the same direction, and polarized light emitted from the second polarization separation element comprising an optical deflection element for deflecting the optical path, and a projection lens for projecting the polarized light from the light deflection element,
The polarizing element is:
When defining a basic unit region having the same size as the pixel of the spatial light modulator ,
A structural birefringent body having a periodic groove-like structure which is not larger than the pixel size and a flat portion is formed in the basic unit,
When the basic unit is arranged so as to correspond to the number of pixels of the spatial light modulation element, a structural birefringent body that converts p-polarized light emitted from the spatial light modulation element into s-polarized light, and emitted from the spatial light modulation element An image display device having a configuration in which flat portions that transmit the p-polarized light as it is are alternately arranged . At least a light source, a spatial light modulation element that emits modulated light from the light source, a polarizing element and emits the separated light emitted from the spatial light modulation element into p-polarized light and s-polarized light of the same rate, A birefringent element that emits p + s-polarized polarized light with the same path of p-polarized light and s-polarized light emitted from the polarizing element, and an optical deflector that deflects the optical path of the polarized light emitted from the birefringent element ; , and a projection lens for projecting the polarized light from the light deflection element,
The polarizing element is:
When defining a basic unit region having the same size as the pixel of the spatial light modulator ,
A structural birefringent body having a periodic groove-like structure which is not larger than the pixel size and a flat portion is formed in the basic unit,
When the basic unit is arranged so as to correspond to the number of pixels of the spatial light modulation element, a structural birefringent body that converts p-polarized light emitted from the spatial light modulation element into s-polarized light, and emitted from the spatial light modulation element An image display device having a configuration in which flat portions that transmit the p-polarized light as it is are alternately arranged . The image display device according to claim 2,
2. The image display device according to claim 1, wherein the birefringent element is a laminated type. The image display device according to any one of claims 1 to 3,
The image display device, wherein the spatial light modulator is a transmissive type. The image display device according to any one of claims 1 to 3,
The image display device according to claim 1, wherein the spatial light modulator is of a reflective type. The image display device according to any one of claims 1 to 5,
The image display device, wherein the light deflection element has a mechanical drive mechanism. The image display device according to any one of claims 1 to 5,
A liquid crystal is used as the light deflection element.

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