JP4016940B2 - Spatial light modulator and projector - Google Patents

Description

  The present invention relates to a spatial light modulation device and a projector, and more particularly to a liquid crystal spatial light modulation device.

  As an image display device, a dot matrix image display device such as a liquid crystal panel (liquid crystal display device), a CRT display device, or a plasma display device is often used. The dot matrix image display device expresses an image by a large number of pixels arranged two-dimensionally and periodically. At this time, a so-called sampling noise is generated due to the periodic arrangement structure, and a phenomenon in which the image quality is deteriorated (the image looks rough) is observed. And the method of reducing the phenomenon in which an image quality deteriorates is proposed (for example, refer patent document 1).

JP-A-8-122709

  In a dot matrix image display device, a light shielding portion called a black matrix is provided in a region between pixels in order to reduce unnecessary light. In recent years, as a usage mode of an image display device, a large screen is often observed from a relatively short distance. For this reason, the observer may recognize the black matrix image. As described above, the conventional dot matrix image display device has a problem that the image quality is deteriorated due to the black matrix image, such as an image with less smoothness or an image having roughness. In the above-mentioned Patent Document 1, it is difficult to reduce image quality degradation caused by a black matrix image.

  The present invention has been made to solve the above-described problems, and a spatial light modulation device and a projector capable of obtaining smooth image quality without an observer recognizing an image of a light-shielding portion such as a black matrix. The purpose is to provide.

In order to solve the above-described problems and achieve the object, according to the present invention, a modulation unit that modulates incident light according to an image signal and emits the light, and an emission side of the modulation unit are provided. A spatial light modulator having a refracting unit that refracts the light, wherein the modulating unit is a light-shielding unit provided between a plurality of pixel units arranged in a matrix and the plurality of pixel units. The refraction part includes a prism group including a prism element including at least a refraction surface and a flat part substantially parallel to the surface on which the pixel part is formed, and the plurality of pixel parts Light from one of the pixel units is incident on at least some of the plurality of prism groups, and the refracting surface is a projection surface that is separated from the refracting unit by a predetermined distance. The projected image of the light is guided onto the projected image of the light shielding part. A direction of the refracting surface and an angle formed between the refracting surface and a reference surface formed in a direction substantially perpendicular to the optical axis, and transmitted or reflected through the flat portion of the light from the pixel portion. The light travels substantially straight to form the projected image, and when the area occupied by one of the prism elements in the prism group is a unit area, the ratio of the area of the refractive surface to the unit area is Corresponding to the light intensity of the projection image of the pixel portion, the area of the flat portion and the area of the refracting surface are the total light intensity from the flat portion on the projection surface, PW0, and the refraction on the projection surface. When the total light intensity passing through the surface is PW1,
PW0 > PW1
It is possible to provide a spatial light modulation device that is configured to satisfy the above.

Thereby, light from one pixel unit enters the prism group. The light incident on the prism group is refracted by the refracting surface of the prism element and the optical path is bent in a predetermined direction. At this time, the direction in which the optical path is bent and its size (refraction angle) can be controlled according to the direction of the refracting surface and the angle between the refracting surface and the reference surface. In the present invention, the projection image of the pixel portion formed by the refracted light is guided onto the projection image of the light shielding portion on the projection surface that is separated from the refracting portion by a predetermined distance. As a result, a projection image of the pixel portion is formed in a superimposed manner on the projection image region of the light shielding portion on the projection plane that is separated from the refraction portion by a predetermined distance. Therefore, on the projection surface, it is possible to observe a smooth image with a reduced feeling of roughness without the observer recognizing the light shielding portion.
Of the light from the pixel portion, light incident on the refracting surface of the prism element is refracted according to the direction, angle, and area of the refracting surface. Here, when a part of the refracting surface is a flat part substantially parallel to the surface on which the pixel part is formed, the light incident on the flat part is transmitted without being refracted. Hereinafter, as appropriate, in this specification, a projected image of a pixel portion formed by light that has traveled straight through a flat portion and is transmitted is referred to as a “direct transmission image”, and a projected image of the pixel portion that is formed by light that has been transmitted through a prism and refracted This is called “refracted transmission image”. By forming the direct transmission image of the pixel portion, in addition to the projection image of the original pixel portion, a projection image of the pixel portion whose optical path is refracted can be formed.
Here, the size of the prism element is one or more within the included angle defined by the illumination light or the F-number of the projection lens in front of the light traveling direction from the point of the light shielding portion arranged on the spatial modulation element. By arranging the prism elements assigned to the area ratio, a pixel having a light quantity ratio assigned by the area of the direct transmission image and the refractive transmission image can be obtained.
The total light intensity of the direct transmission image corresponds to the area of the flat portion. The total light intensity of the refracted transmission image corresponds to the area of the refracting surface. On the projection surface, the refracted transmission image is formed around the direct transmission image. Here, when paying attention to one pixel portion, if the sum of the light intensities of the refracted transmission image becomes larger than the sum of the light intensities of the direct transmission images, the observer will be doubled like a ghost, for example. It may be recognized like an image. For this reason, the image quality of the projected image is deteriorated. On the other hand, in this aspect, it is comprised so that PW0 > PW1 may be satisfied. Therefore, the observer can observe an image that is seamless, smooth, and has a reduced feeling of roughness without recognizing the light-shielding portion around the direct transmission image that is the projection image of the original pixel portion . Good Mashiku, it is desirable to satisfy the PW0> 0.9 × PW1. As a result, the feeling of roughness can be further reduced seamlessly.

According to a preferred aspect of the present invention, the pixel portion has a substantially rectangular shape, the light-shielding portion has a shape in which band-shaped portions having a predetermined width are arranged in a lattice shape, and is in the direction of the center line of the light-shielding portion. On the other hand, it is desirable that the direction along the side of the prism element is approximately 45 ° . For this reason, it is possible to obtain a so-called seamless image with little blur between the pixel portions and a smooth image with a reduced feeling of roughness.

According to a preferred aspect of the present invention, the pixel portion has a substantially rectangular shape, the light-shielding portion has a shape in which band-shaped portions having a predetermined width are arranged in a lattice shape, and the prism group of the refracting portion includes: It is desirable that the prism element is composed of a prism element having a polygonal pyramid shape having a plane portion in the vicinity of the apex portion of the cone . In a general dot matrix image display device, rectangular pixel portions are arranged in a matrix form. A light shielding portion such as a black matrix portion is provided in a region between adjacent pixel portions. Here, when the prism element has a polygonal pyramid shape, the direction of the refracting surface can be changed in various directions. For this reason, the projection image of the pixel portion can be formed in various directions. Further, the angle and area of the refracting surface can be arbitrarily set. As a result, the position and light amount of the projected image of the pixel portion can also be controlled. The “polygonal pyramid shape” refers to a shape including a shape having a flat surface in the vicinity of the apex portion of the cone in addition to the cone shape having a polygonal bottom surface.

Further, according to a preferred aspect of the present invention, it is desirable that the prism group of the refracting portion is composed of a substantially quadrangular pyramid-shaped prism element having a flat portion in the vicinity of the apex portion of the cone . By forming the prism element into a quadrangular pyramid shape, the projected image of the pixel portion can be formed in a direction orthogonal to the bottom side of the prism element. For this reason, when the pixel portion has a rectangular shape, the projection image of the pixel portion can be more efficiently superimposed on the projection image of the light shielding portion.

  Further, according to a preferred aspect of the present invention, the pixel portion has a substantially rectangular shape, the light shielding portion has a shape in which strip-shaped portions having a predetermined width are arranged in a lattice shape, and the prism group of the refracting portion includes the first prism group. The cross-sectional shape in the direction is a substantially trapezoidal shape, and is composed of two sets of prism elements having a longitudinal direction in a second direction substantially orthogonal to the first direction. It is desirable that the trapezoidal slopes are provided so as to be orthogonal to each other and correspond to the refractive surface. The cross-sectional shape of the prism element in the first direction is a substantially trapezoidal shape. The trapezoidal slope acts as a refractive surface. For this reason, the projection image of the pixel portion by the light refracted on the inclined surface can be formed in a direction orthogonal to the longitudinal direction of the prism element. In this embodiment, the longitudinal directions of the two sets of prism elements are further substantially orthogonal to each other. As a result, when the pixel portion has a rectangular shape, the projection image of the pixel portion can be superimposed on the projection image of the light shielding portion around the pixel portion more efficiently.

  According to a preferred aspect of the present invention, the first peak value of the intensity distribution of the projection image of the pixel portion formed by light from the flat portion is formed by light passing through the refracting surface on the projection surface. It is desirable that the region between the first peak value and the second peak value that is larger than the second peak value of the intensity distribution of the projected image of the pixel portion has a light intensity corresponding to a predetermined intensity distribution curve. . Thereby, the observer recognizes an appropriate light intensity distribution in a region between the direct transmission image and the adjacent direct transmission image. For this reason, the observer can observe a high-resolution image that is smooth and has a rough feeling without recognizing the light-shielding portion.

  Further, according to the present invention, a light source unit that supplies light including first color light, second color light, and third color light, and a spatial light modulation device for first color light that modulates the first color light according to an image signal. A spatial light modulator for second color light that modulates the second color light according to an image signal, a spatial light modulator for third color light that modulates the third color light according to an image signal, and the first color light The first color light, the second color light, and the third color light modulated by the spatial light modulation device for the second color light, the spatial light modulation device for the second color light, and the spatial light modulation device for the third color light, respectively. A first color light spatial light modulation device, a second color light spatial light modulation device, the first color light spatial light modulation device, and the first color light spatial light modulation device; The three-color spatial light modulator is a projector characterized by the spatial light modulator described above. It can provide the data. Here, when a color separation optical system described later is not provided, a solid-state light emitting element such as a light emitting diode or a semiconductor laser that supplies first color light, second color light, and third color light, respectively, is used as the light source unit. it can.

  Thereby, in the image projected on the screen, the projection image of the pixel portion is formed so as to be superimposed on the region of the projection image of the light shielding portion. Therefore, on the screen, it is possible to observe a smooth image with a reduced feeling of roughness without the observer recognizing the image of the light shielding portion.

  According to a preferred aspect of the present invention, each of the first color light spatial light modulation device, the second color light spatial light modulation device, and the third color light spatial light modulation device has the refracting section. It is desirable that The angle at which light is refracted by the refracting surface depends on the wavelength of the light. For example, when a plurality of lights in different wavelength regions are incident on the same refracting surface, the angle of refraction differs for each wavelength region. In this aspect, the spatial light modulation device for the first color light, the spatial light modulation device for the second color light, and the spatial light modulation device for the third color light each have the refraction part. Thereby, the angle of the refracting surface suitable for the wavelength of each color light can be set. As a result, the projected image of the pixel portion can be accurately formed at a predetermined position.

  According to a preferred aspect of the present invention, it is desirable that the refracting portion is provided on the incident side or the emission side of the color synthesis optical system. Instead of providing a refracting part for each color light spatial light modulator, a refracting part may be provided on the incident side or the exit side of a color synthesis optical system such as a cross dichroic prism. Accordingly, since only one refracting portion is required, the configuration is simplified and the manufacturing cost can be reduced. Two examples of the arrangement positions of the prism elements have been described above, but it has been confirmed that the same effect can be obtained by arranging the prism elements between the black matrix formation layer position and the visual image formation point of the direct viewer. Yes.

  Moreover, according to a preferable aspect of the present invention, it is preferable to further include a color separation optical system that separates the light supplied from the light source unit into the first color light, the second color light, and the third color light. . For example, the light source unit may supply the first color light, the second color light, the third color light, and light in all the wavelength ranges, such as an ultra-high pressure mercury lamp. In this case, in this case, the light from the light source unit can be separated into the first color light, the second color light, and the third color light by the color separation optical system, and each color light can be modulated according to the image signal.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(Explanation of the entire projector)
First, a schematic configuration of a projector according to Embodiment 1 of the present invention will be described with reference to FIG. Next, a characteristic configuration of the present embodiment will be described with reference to FIG. First, in FIG. 1, an ultra-high pressure mercury lamp 101 as a light source unit includes red light (hereinafter referred to as “R light”) as first color light and green light (hereinafter referred to as “G light”) as second color light. And blue light (hereinafter referred to as “B light”) which is the third color light. The integrator 104 uniformizes the illuminance distribution of the light from the ultrahigh pressure mercury lamp 101. The light whose illuminance distribution is made uniform is converted into polarized light having a specific vibration direction, for example, s-polarized light by the polarization conversion element 105. The light converted into the s-polarized light is incident on the R light transmitting dichroic mirror 106R constituting the color separation optical system. Hereinafter, the R light will be described. The R light transmitting dichroic mirror 106R transmits R light and reflects G light and B light. The R light transmitted through the R light transmitting dichroic mirror 106R is incident on the reflection mirror 107. The reflection mirror 107 bends the optical path of the R light by 90 degrees. The R light whose optical path is bent enters the spatial light modulator for first color light 110R that modulates the R light as the first color light according to the image signal. The spatial light modulator for first color light 110R is a transmissive liquid crystal display device that modulates R light according to an image signal. Since the polarization direction of the light does not change even if it passes through the dichroic mirror, the R light incident on the first color light spatial light modulator 110R remains as s-polarized light.

  The first color light spatial light modulator 110R includes a λ / 2 phase difference plate 123R, a glass plate 124R, a first polarizing plate 121R, a liquid crystal panel 120R, and a second polarizing plate 122R. The detailed configuration of the liquid crystal panel 120R will be described later. The λ / 2 phase difference plate 123R and the first polarizing plate 121R are arranged in contact with a light-transmitting glass plate 124R that does not change the polarization direction. Thereby, the problem that the first polarizing plate 121R and the λ / 2 phase difference plate 123R are distorted by heat generation can be avoided. In FIG. 1, the second polarizing plate 122R is provided independently. However, the second polarizing plate 122R may be disposed in contact with the exit surface of the liquid crystal panel 120R or the entrance surface of the cross dichroic prism 112.

  The s-polarized light incident on the first color light spatial light modulator 110R is converted into p-polarized light by the λ / 2 phase difference plate 123R. The R light converted into p-polarized light passes through the glass plate 124R and the first polarizing plate 121R as it is and enters the liquid crystal panel 120R. The p-polarized light incident on the liquid crystal panel 120R is converted into s-polarized light by modulation according to the image signal. The R light converted into s-polarized light by the modulation of the liquid crystal panel 120R is emitted from the second polarizing plate 122R. In this way, the R light modulated by the first color light spatial light modulator 110R is incident on the cross dichroic prism 112 which is a color synthesis optical system.

  Next, the G light will be described. The light paths of the G light and the B light reflected by the R light transmitting dichroic mirror 106R are bent by 90 degrees. The G light and the B light whose optical paths are bent enter the B light transmitting dichroic mirror 106G. The B light transmitting dichroic mirror 106G reflects the G light and transmits the B light. The G light reflected by the B light transmitting dichroic mirror 106G is incident on the second color light spatial light modulator 110G that modulates the G light, which is the second color light, according to the image signal. The spatial light modulator for second color light 110G is a transmissive liquid crystal display device that modulates G light according to an image signal. The second color light spatial light modulator 110G includes a liquid crystal panel 120G, a first polarizing plate 121G, and a second polarizing plate 122G. Details of the liquid crystal panel 120G will be described later.

  The G light incident on the second color light spatial light modulator 110G is converted into s-polarized light. The s-polarized light incident on the second color light spatial light modulator 110G passes through the first polarizing plate 121G as it is and enters the liquid crystal panel 120G. The s-polarized light incident on the liquid crystal panel 120G is converted into p-polarized light by modulation according to the image signal. The G light converted into p-polarized light by the modulation of the liquid crystal panel 120G is emitted from the second polarizing plate 122G. Thus, the G light modulated by the second color light spatial light modulator 110G enters the cross dichroic prism 112, which is a color synthesis optical system.

  Next, the B light will be described. The B light transmitted through the B light transmitting dichroic mirror 106G passes through the two relay lenses 108 and the two reflection mirrors 107, and the third light that modulates the B light as the third color light in accordance with the image signal. The light enters the color light spatial light modulator 110B. The spatial light modulator for third color light 110B is a transmissive liquid crystal display device that modulates B light according to an image signal.

  The reason why the B light passes through the relay lens 108 is that the optical path length of the B light is longer than the optical path lengths of the R light and the G light. By using the relay lens 108, it is possible to guide the B light transmitted through the B light transmitting dichroic mirror 106G directly to the third color light spatial light modulator 110B. The spatial light modulator for third color light 110B includes a λ / 2 phase difference plate 123B, a glass plate 124B, a first polarizing plate 121B, a liquid crystal panel 120B, and a second polarizing plate 122B. Note that the configuration of the spatial light modulation device 110B for the third color light is the same as the configuration of the spatial light modulation device 110R for the first color light described above, and thus detailed description thereof is omitted.

  The B light incident on the spatial light modulator for third color light 110B is converted into s-polarized light. The s-polarized light incident on the third color light spatial light modulator 110B is converted into p-polarized light by the λ / 2 phase difference plate 123B. The B light converted into p-polarized light passes through the glass plate 124B and the first polarizing plate 121B as it is, and enters the liquid crystal panel 120B. The p-polarized light incident on the liquid crystal panel 120B is converted into s-polarized light by modulation according to the image signal. The B light converted into the s-polarized light by the modulation of the liquid crystal panel 120B is emitted from the second polarizing plate 122B. The B light modulated by the third color light spatial light modulator 110B is incident on the cross dichroic prism 112 which is a color synthesis optical system. As described above, the R light transmissive dichroic mirror 106R and the B light transmissive dichroic mirror 106G constituting the color separation optical system convert the light supplied from the ultrahigh pressure mercury lamp 101 to the R light that is the first color light and the second light. The light is separated into G light, which is colored light, and B light, which is third color light.

  The cross dichroic prism 112, which is a color synthesis optical system, is configured by arranging two dichroic films 112a and 112b perpendicularly to an X shape. The dichroic film 112a reflects B light and transmits R light and G light. The dichroic film 112b reflects R light and transmits B light and G light. As described above, the cross dichroic prism 112 has the R light and G light modulated by the first color light spatial light modulation device 110R, the second color light spatial light modulation device 110G, and the third color light spatial light modulation device 110B, respectively. And B light. The projection lens 114 projects the light combined by the cross dichroic prism 112 onto the screen 116. Thereby, a full color image can be obtained on the screen 116.

  As described above, the light incident on the cross dichroic prism 112 from the first color light spatial light modulator 110R and the third color light spatial light modulator 110B is set to be s-polarized light. The light incident on the cross dichroic prism 112 from the second color light spatial light modulator 110G is set to be p-polarized light. In this way, by changing the polarization direction of the light incident on the cross dichroic prism 112, the light emitted from the spatial light modulators for the respective color lights in the cross dichroic prism 112 can be effectively combined. The dichroic films 112a and 112b are usually excellent in the reflection characteristics of s-polarized light. For this reason, R light and B light reflected by the dichroic films 112a and 112b are s-polarized light, and G light transmitted through the dichroic films 112a and 112b is p-polarized light.

(Configuration of LCD panel)
Next, details of the liquid crystal panel will be described with reference to FIG. The projector 100 described with reference to FIG. 1 includes three liquid crystal panels 120R, 120G, and 120B. These three liquid crystal panels 120R, 120G, and 120B differ only in the wavelength region of light to be modulated, and have the same basic configuration. Therefore, the following description will be made with the liquid crystal panel 120R as a representative example.

  FIG. 2 is a perspective sectional view of the liquid crystal panel 120R. The R light from the ultrahigh pressure mercury lamp 101 is incident on the liquid crystal panel 120R from the lower side of FIG. A counter substrate 202 having a transparent electrode and the like is formed inside the incident side dust-proof transparent plate 201. A TFT substrate 205 having TFTs (thin film transistors), transparent electrodes, and the like is formed inside the emission-side dust-proof transparent plate 206. Then, the incident side dustproof transparent plate 201 and the emission side dustproof transparent plate 206 are bonded together with the counter substrate 202 and the TFT substrate 205 facing each other. A liquid crystal layer 204 for image display is sealed between the counter substrate 202 and the TFT substrate 205. In addition, a black matrix forming layer 203 is provided on the incident light side of the liquid crystal layer 204 for shielding light.

  A prism group 210 including a plurality of prism elements 211 is formed on the exit side surface of the exit side dust-proof transparent plate 206. Details of the configuration and operation of the prism group 210 will be described later. In the configuration shown in FIG. 1, the first polarizing plate 121R and the second polarizing plate 122R are provided separately from the liquid crystal panel 120R. However, instead of this, a polarizing plate may be provided between the entrance-side dust-proof transparent plate 201 and the counter substrate 202, between the exit-side dust-proof transparent plate 206 and the TFT substrate 205, or the like. Further, the prism group 210 may be formed on the second polarizing plate 122R or formed on the R light incident surface of the cross dichroic prism 112.

(Configuration of the opening corresponding to the pixel portion)
FIG. 3 is a plan view of the black matrix forming layer 203. The black matrix portion 220 which is a light shielding portion shields the R light incident from the ultrahigh pressure mercury lamp 101 so as not to be emitted to the screen 116 side. The black matrix portion 220 has predetermined widths W1 and W2, and is formed in a lattice shape in the orthogonal direction. A rectangular region surrounded by the black matrix portion 220 forms an opening 230. The opening 230 allows the R light from the extra-high pressure mercury lamp 101 to pass through. The R light transmitted through the opening 230 passes through the counter substrate 202, the liquid crystal layer 204, and the TFT substrate 205 as shown in FIG. The polarization component of the R light is modulated in the liquid crystal layer 204 in accordance with the image signal. In this way, the pixel portion in the projected image is formed by the light that has been modulated by being transmitted through the opening 230, the liquid crystal layer 204, and the TFT substrate 205. Since this light is light transmitted through the opening 230, the position and size of the opening 230 correspond to the position and size of the pixel portion, respectively. Further, the center line CL of the belt-like black matrix portion 220 is indicated by a one-dot chain line. Hereinafter, for convenience of description, a region indicated by a thick line surrounded by the center line CL is referred to as a periodic region 240. As is apparent from the figure, the adjacent periodic regions 240 are periodically and repeatedly arranged without gaps.

(Projected image of aperture)
FIG. 4 is an enlarged view of an image projected on the screen 116 by a projector according to the prior art. An aperture image 230 </ b> P is projected surrounded by the band-shaped black matrix image 220. Also, corresponding to the periodic region 240, a periodic region image 240P surrounded by a thick line in FIG. 4 is projected. Further, a position where the center line images CLP intersect is defined as an intersection CP. In the following description of all the embodiments including the present embodiment, description will be made using an image projected on the screen 116 by the projection lens 114. Here, when the first spatial light modulator for light 110R itself is taken out and considered, the projection lens 114 is not interposed. In this case, it can be handled as a projection image projected on a virtual projection plane that is a predetermined distance away from the prism group 210 that is a refraction part. The projected image by the projector 100 and the projected image by the first spatial light modulator for the first color light 110R are substantially the same with only the image magnification being different. For this reason, hereinafter, a description will be given by taking a projected image projected on the screen 116 as an example.

(Positional relationship between prism group and aperture)
FIG. 5 is a cross-sectional view showing the relationship between the black matrix forming layer 203 and the prism group 210 as a refracting portion. Here, in order to facilitate understanding, the illustration of other components other than the black matrix forming layer 203 and the prism group 210 is omitted. The R light transmitted through the opening 230 corresponding to one pixel portion travels as a conical divergent light. The R light is incident on at least some of the prism groups 210. The prism group 210 includes a prism element 211 having at least a refractive surface 212 and a flat portion 213. The flat portion 213 is a surface substantially parallel to the surface 230a where the opening 230 corresponding to the pixel portion is formed. A plurality of prism elements 211 are regularly arranged at a constant period to constitute a prism group 210.

  6A, 6B, and 6C are plan views showing the positional relationship between the opening 230 and the prism group 210. FIG. Each prism element 211 has a substantially square shape as shown in FIG. Then, with respect to the direction of the center line CL of the black matrix forming layer 203 shown in FIG. 6A, the direction along the side portion 211a of each prism element 211 forms about 45 ° as shown in FIG. It is configured as follows. As described above, the light transmitted through one opening 230 is incident on a part of the prism group 210 including the plurality of prism elements 211.

(Explanation of refraction angle and refraction direction)
Next, the amount of angle by which the light transmitted through the opening 230 is refracted by the above configuration will be described with reference to FIG. FIG. 7 is an enlarged view showing the vicinity of the prism group 210 that is a refracting portion. Consider a case where a medium (for example, air) between the prism group 210 and the screen 116 has a refractive index n1, and members constituting the prism group 210 have a refractive index n2. The refracting surface 212 is formed so as to have an angle θ with respect to a reference surface 213 a obtained by extending the flat portion 213. Hereinafter, the angle θ is referred to as an inclination angle.

  For simplicity, parallel light out of the light from the opening 230 will be described. A light beam incident on the flat portion 213 enters the flat portion 213 perpendicularly. For this reason, without being refracted by the flat portion 213, it proceeds straight as it is to form a projected image on the screen 116. On the other hand, the light incident on the refracting surface 212 is refracted so as to satisfy the following conditional expression.

n1 · sinβ = n2 · sinα
Here, the angle α is an incident angle based on the normal line N of the refractive surface 212, and the angle β is an exit angle.

  Further, on the screen 116 that is separated from the prism group 210 by a distance L, the position of the light that travels straight, the position of the refracted light, and the distance S are expressed by the following equations.

S = L × Δβ
Δβ = β-α
Thus, by controlling the prism tilt angle θ of the refracting surface 212, the distance S, which is the amount of movement of the aperture image 230P on the screen 116, can be arbitrarily set.

  Further, as apparent from FIG. 7, the direction in which the light beam LL2 is refracted depends on the direction of the refracting surface 212. In other words, by controlling the direction of the refractive surface 212 with respect to the opening 230, the direction in which the opening image 230P is formed on the screen 116 can be arbitrarily set.

(Area ratio of refractive surface)
Returning to FIG. 6C, it is assumed that one side of the square prism element 211 has a length La and one side of the flat portion 213 has a length Lb. An area La × La occupied by one prism element 211 in the prism group 210 is defined as a unit area. The flat part 213 has an area FS = Lb × Lb. The four refractive surfaces 212a, 212b, 212c, and 212d have areas P1, P2, P3, and P4, respectively. Here, the amount of light that has traveled straight through the flat portion 213 corresponds to the area FS of the flat portion 213 occupying the unit area. Similarly, the total amount of light refracted by the four refracting surfaces 212a, 212b, 212c, 212d corresponds to the total area P1 + P2 + P3 + P4 of the refracting surfaces 212a, 212b, 212c, 212d occupying the unit area. Here, if the areas P1, P2, P3, and P4 of the four refracting surfaces 212a, 212b, 212c, and 212d are substantially equal, the total area is P1 + P2 + P3 + P4 = 4 × P1. In other words, by controlling the area of the flat portion 213 or the refracting surface 212, the amount of light that has traveled straight or refracted through the prism element 210 in the screen 116 can be arbitrarily set.

  In consideration of the amount of light on the screen 116, it is desirable that the amount of light of the projected image (directly transmitted image) transmitted straight through the flat portion 213 is equal to the amount of light of the projected image refracted by the refractive surface 212. For example, if the length La = 1.0 and the length Lb = 0.707, the unit area of the prism element 211 is 1.0 (= 1.0 × 1.0), and the area FS of the flat portion 213 is 0.00. 5 (= 0.707 × 0.707). The total area (4 × P1) of the four refracting surfaces 212a, 212b, 212c, and 212d having the same area is 0.5 (= 1.0−0.5). In this way, the amount of light that passes straight through the flat portion 213 and the total amount of light refracted by the four refracting surfaces 212a, 212b, 212c, and 212d can be made equal.

(Contents of the projected image)
When the liquid crystal panel 120R having the above-described configuration is used, an image projected by the R light projected on the screen 116 will be described with reference to FIGS. FIG. 8A shows one periodic region image 240 </ b> P on the screen 116. The light that is substantially perpendicularly incident on the flat portion 213 of the prism element 211 travels straight without being refracted by the flat portion 213. The straightly traveling light forms an opening image (direct transmission image) 230P at the center of the periodic region 240P on the screen 116.

  Next, consider the light incident on the refractive surface 212 a of the prism element 210. The light incident on the refracting surface 212a is refracted by the direction of refraction 212a, the inclination angle θ, and the refraction direction, the amount of refraction, and the amount of light refracted corresponding to the area P1. As described above, the direction along the side 211a of the prism element 211 and the direction of the center line CL of the black matrix forming layer 203 are configured to be approximately 45 °. Therefore, for example, as shown in FIG. 8A, the light refracted by the refracting surface 212a has an opening image 230Pa at a position away from the opening image (direct transmission image) 230P by the distance S described above in the arrow direction. Form. In the following description, for the sake of simplicity, it is assumed that there is no up / down / left / right reversal of the image due to the image forming action of the projection lens 114. Further, it is assumed that the observer always observes from the direction of viewing the ultrahigh pressure mercury lamp 101 that is the light source unit. For example, the image projected on the screen 116 is also observed from the back side of the screen 116 from the direction in which the ultrahigh pressure mercury lamp 101 is viewed (the direction in which light is directed).

  Similarly, the light refracted by the refractive surface 212b forms an opening image 230Pb at the position shown in FIG. The light refracted by the refracting surface 212c forms an opening image 230Pc at the position shown in FIG. The light refracted by the refracting surface 212d forms an opening image 230Pd at the position shown in FIG. FIGS. 8A to 8D illustrate the opening image 230Pa, 230Pb, 230Pc, and 230Pd separately for the same peripheral area image 240P.

  Actually, these four opening images 230Pa, 230Pb, 230Pc, and 230Pd are superimposed and projected as shown in FIG. As described above, the refraction surface 212 has the opening images 230Pa and 230Pb of the opening 230 corresponding to the pixel portion on the screen 116 which is a projection (projection) surface separated from the prism group 210 which is the refraction portion by a predetermined distance L. The direction of the refracting surface 212 and the inclination angle θ are such that 230Pc and 230Pd are guided onto the black matrix portion image 220P that is a projection image of the black matrix portion 220 that is a light shielding portion. As a result, aperture images 230Pa, 230Pb, 230Pc, and 230Pd are formed on the screen 116 so as to overlap with the region of the black matrix image 220P. Accordingly, the observer does not recognize the black matrix image 220P on the screen 116.

  In particular, in this embodiment, the periodic region image 240P is filled with the opening images 230Pa, 230Pb, 230Pc, and 230Pd without any gaps. As described above, the prism element 211 includes the intersections CPa, CPb, CPc, CPd of the center line image CLP of the black matrix portion image 220P, which is a light shielding portion image arranged in a grid, and the opening of the opening portion 230 that is a pixel portion. The partial image (direct transmission image) 230P has an orientation of the refracting surface 212 and an inclination angle θ of the refracting surface 212 such that one corner of the partial image (direct transmission image) 230P substantially coincides. For this reason, it is possible to obtain a so-called seamless image with little blur between the pixel portions and a smooth image with a reduced feeling of roughness.

(Prism group manufacturing method)
Next, returning to FIG. 2, a method for manufacturing the prism group 210 will be described. The prism group 210 is integrally formed on the exit surface of the exit side dust-proof transparent plate 206. The exit side dust-proof transparent plate 206 is a transparent parallel plate glass. A prism group 210 is formed on one surface of the parallel plate glass by photolithography. Specifically, a mask is formed by patterning a photoresist layer on a parallel plate glass so as to have a desired prism shape, for example, a quadrangular pyramid shape, using a gray scale method. Then, the prism group 210 is formed by an RIE (reactive ion etching) method using a fluorine-based gas such as CHF ₃ . The prism group 210 can also be formed by a wet etching method using hydrofluoric acid. As described above, the emission-side dust-proof transparent plate 206, which is a parallel plate glass having the prism group 210 formed on one surface, is incorporated most on the emission side in the manufacturing process of the liquid crystal panel 120R.

  Furthermore, another manufacturing method of the prism group 210 will be described. Optical epoxy resin is applied to one side of the parallel plate glass. Next, a mold having a pattern in which irregularities are reversed from a desired prism shape is prepared. Then, the mold is transferred by pressing the mold against the epoxy resin. Finally, the optical epoxy resin is irradiated with ultraviolet rays and cured to form the prism group 210.

  In addition, other methods can be adopted when performing mold transfer. The parallel plate glass is heated and softened to the extent necessary for mold transfer. Then, the above-described mold is pressed onto one surface of the softened parallel plate glass to perform mold transfer. This also allows the prism group 210 to be formed on the parallel plate glass.

  The prism group 210 is not limited to being formed integrally with the emission-side dustproof transparent plate 206. For example, a prism group 210 having a desired prism shape is separately manufactured as a pattern sheet by a hot press method. Then, the pattern sheet is cut into a required size. Next, the cut pattern sheet is attached to the exit surface side of the parallel plate glass using an optically transparent adhesive. This also allows the prism group 210 to be formed on the parallel plate glass.

  More preferably, it is desirable to prevent dust and the like from adhering to the surface of the prism group 210. For this purpose, a coating layer made of a transparent resin having a low refractive index is formed on the exit side surface of the prism group 210. For example, the prism group 210 is formed of an optical epoxy high refractive index resin having a refractive index n = 1.56. The coating layer is formed of, for example, an optical epoxy low refractive index resin having a refractive index n = 1.38. Moreover, the refractive index of the member which comprises the prism group 210, and the refractive index of a coating layer can also be made to correspond substantially. Thereby, it is possible to reduce the positional deviation of the refracted light on the screen 116 due to the manufacturing error of the refracting surface 212 and the like.

Here, the size of the arrangement prism element will be described with reference to FIG. The size of the prism element 211a to be arranged is defined by the illumination light or the F number of the projection lens in front of the light traveling direction from a certain point of the black matrix forming layer 203 which is a light shielding part arranged in the spatial modulation element 120R. If the F-number of the projection lens is f, the stagnation angle is θ, and the distance between the black matrix forming layer and the prism group 210 is L, the maximum prism size diameter Φ is given by It is desirable that the size is less than or equal to
Φ = 2 × L (Asin (1 / 2f))
Therefore, the size of the prism elements 211a allocated to the area ratio is approximately within the diameter Φ, and the ratio of the flat portion area and the projection angle area of each prism is approximately matched with the design value within the diameter Φ, thereby allowing direct transmission. A pixel having a light quantity ratio allocated by the area of the image and the refractive transmission image is obtained.
More desirably, in order to improve the uniformity of the image obtained on the screen 116, it is desirable to employ a configuration in which ten or more prism elements 211a are arranged within the diameter Φ.

(Relationship between wavelength and prism element shape)
In the above description, the R light is described as a representative example. The basic configuration of the liquid crystal panel 120G of the second color light spatial light modulator 110G for the G light and the liquid crystal panel 120B of the third color light spatial light modulator 110B for the B light are the same as those of the R light. Specifically, the spatial light modulator for first color light 110R, the spatial light modulator for second color light 110G, and the spatial light modulator for third color light 110B each have a prism group 210 that is a refracting unit. ing.

  Here, the angle of refraction at the refracting surface 212 varies depending on the wavelength of light. For this reason, when accurately controlling the position of the image that is refracted and projected on the screen 116, it is desirable to consider the wavelength of the refracted light. For example, the ultra-high pressure mercury lamp 101 as the light source unit has an emission spectrum distribution as shown in FIG. The horizontal axis in FIG. 10 is the wavelength, and the vertical axis is the arbitrary intensity unit. Then, light having a peak wavelength of the emission line spectrum of about 440 nm is used as B light, and light of about 550 nm is used as G light. In addition, light in the vicinity of approximately 650 nm, which is the central wavelength of the light intensity integral value, is used as R light. When the light of these wavelengths is refracted by the refracting surface 212, the inclination angle θ of the refracting surface 212 is controlled so that a predetermined projection image is formed on the screen 116. Thereby, a high-quality image with little color misregistration can be obtained on the screen 116.

(Numerical example)
Specifically, when the pitch PT of the prism elements 211 shown in FIG. 5 is 1 mm, the optimum height (depth) H is approximately 45.5 μm.

  Further, when the prism groups 210 are formed on the emission side surfaces of the liquid crystal panels 120R, 120G, and 120B, for example, on the quartz substrate surface, numerical examples are given for the inclination angle θ of the prism element 211. For example, the distance S = 8.5 μm, which is the amount of movement on the screen 116. At this time, the inclination angles θ of the prism elements 211 in the R light, G light, and B light are 0.31 °, 0.31 °, and 0.30 °, respectively. The reason why the inclination angle differs for each color is that, as described above, the refractive index of the members constituting the prism group 210 differs depending on the wavelength. In addition, when the prism group 210 for each color is provided on the incident surface of each color light of the cross dichroic prism 112, the inclination angle θ of each prism element 211 in the R light, G light, and B light is 0.10 °, respectively. 0.10 ° and 0.099 °.

  Thus, since the inclination angle θ is a small value, it may be difficult to form the prism group 210 by, for example, cutting. Therefore, a material having a refractive index close to the refractive index of the members constituting the prism group 210 is formed by a mold at the interface of the prism group 210. Thereby, the inclination angle θ can be increased and the prism group 210 can be easily manufactured. For example, the difference in refractive index between the members constituting the prism group 210 and the material to be molded is set to 0.3. At this time, when the prism groups 210 are formed on the exit side surfaces of the liquid crystal panels 120R, 120G, and 120B, the amount of movement on the screen 116 is set to the distance S = 8.5 μm, and the inclination of the R light, G light, and B light is inclined. The angles θ are 1.16 °, 1.17 °, and 1.18 °, respectively. In this case, when the prism group 210 for each color is provided on the incident surface of each color light of the cross dichroic prism 112, the inclination angle θ of each prism element 211 for R light, G light, and B light is 0. .31 °, 0.31 °, and 0.31 °.

  FIG. 11 shows a schematic configuration of a projector 1100 according to the second embodiment of the invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. In this embodiment, the prism group 1110 is provided with a prism group 1110 which is a refracting part on the exit side surface of the cross dichroic prism 112 which is a color synthesis optical system.

  FIG. 12 is an enlarged perspective view showing the cross dichroic prism 112. On the exit side surface of the cross dichroic prism 112 to the screen 116, a prism group 1110 having a structure to be described later is formed by using any of the manufacturing methods described above. Accordingly, since only one prism group 1110 is required, the configuration is simplified and the manufacturing cost can be reduced. The prism group 1110 may be provided on the incident side surface of the cross dichroic prism 112. As a result, the refraction angle can be set corresponding to each wavelength, and the refraction image can be optimized.

(Prism element manufacturing method)
FIG. 13 is a view of the prism group 1110 as seen from the AA cross section of FIG. The prism group 1110 includes a first refractive layer 1120 and a second refractive layer 1130 provided on the exit side of the first refractive layer. Prism elements 1140 and 1150 are formed on the first refractive layer 1120 and the second refractive layer 1130, respectively. Note that the prism element 1150 formed in the second refractive layer 1130 is not shown in the shape of the refractive surface because the prism element 1150 is viewed in a cross section along the longitudinal direction.

  Next, a method for manufacturing the prism elements 1140 and 1150 will be described. First, an appropriate amount of an optical epoxy resin having a refractive index n = 1.56 is applied to the exit side surface of the cross dichroic prism 112. Then, a substantially sinusoidal uneven portion corresponding to the shape of the prism element 1140 is formed along a direction substantially perpendicular to the paper surface using a squeegee. Next, the lower high refractive index layer 1120a is formed by irradiating ultraviolet rays to cure the optical epoxy resin. Further, an appropriate amount of an optical epoxy resin having a refractive index n = 1.38 is applied on the lower high refractive index layer 1120a. The surface of the applied optical epoxy resin is flattened using a flat squeegee. Thereafter, the lower epoxy layer 1120b is formed by irradiating ultraviolet rays to cure the optical epoxy resin. Next, an appropriate amount of an optical epoxy resin having a high refractive index is applied on the lower low refractive index layer 1120b. Similarly, a substantially sinusoidal concavo-convex portion corresponding to the shape of the prism element 1150 extending in the horizontal direction of the paper surface is formed using a squeegee. Then, the upper epoxy resin is cured by irradiating with ultraviolet light to form the upper high refractive index layer 1130a. An appropriate amount of an optical epoxy resin having a lower refractive index is applied to the upper side of the upper high refractive index layer 1130a. The surface of the applied optical epoxy resin is flattened using a flat squeegee. Thereafter, the optical epoxy resin is cured by irradiating ultraviolet rays to form the upper low refractive index layer 1130b.

  Here, it is preferable that the optical epoxy resin having a high refractive index has a viscosity enough to maintain the uneven shape of the predetermined prism element. For example, an optical epoxy resin having a high refractive index desirably has a viscosity of about 7 to 25 Pa · s (= 7000 to 25000 cps). Moreover, it is desirable that the optical epoxy resin having a low refractive index has a low viscosity in order to planarize. For example, an optical epoxy resin having a low refractive index desirably has a viscosity of about 0.3 to 6 Pa · s (= 300 to 6000 cps). Note that the lower low-refractive index layer 1120b and the upper low-refractive index layer 1130b can also be formed by spin coating, spray coating, or the like.

  The prism group 1110 can also have the same configuration as the prism group 210 in the first embodiment. In the case of this configuration, a pattern corresponding to the shape of the prism element is previously formed on the pattern sheet by a hot plate method or the like. Then, the pattern sheet is appropriately cut into a necessary size. The cut pattern sheet is fixed to the exit surface side of the cross dichroic prism 112 with an optically transparent adhesive.

(Numerical example)
Also in this embodiment, a projected image as shown in FIG. 9 can be obtained on the screen 116. In particular, since the prism element 1140 has a substantially sinusoidal shape, the amount of light that travels straight without being refracted and the amount of light that is refracted can be made to be a one-to-one ratio, that is, equal. . As a specific numerical example, the optimum height (depth) of the prism element 1140 can be set to 45.5 μm. Accordingly, as in the first embodiment, it is possible to observe a so-called seamless image, a smooth image with a reduced feeling of roughness, with less blur between the pixel portions.

  In addition, when the distance S = 8.5 μm, which is the amount of movement on the screen 116, the inclination angle θ = 0.01 deg. Thus, since the inclination angle θ is a small value, it may be difficult to form the prism group 1110 by cutting, for example. Therefore, a material having a refractive index close to the refractive index of the members constituting the prism group 1110 is formed at the interface of the prism group 1110 using a mold. Thereby, the inclination angle θ can be increased and the prism group 110 can be easily manufactured. For example, the difference in refractive index between the members constituting the prism group 210 and the material to be molded is set to 0.3. At this time, the movement amount on the screen 116 is a distance S = 8.5 μm, and the inclination angle θ is 0.07 °.

  FIG. 14 is a diagram illustrating a projected image on the screen 116 of the projector according to the third embodiment. In the description after the present embodiment, the configuration of the projector is the same as the configuration described in the first embodiment or the second embodiment, and therefore, a duplicate description is omitted. The difference from the first embodiment or the second embodiment is the direction of the refracting surface, the inclination angle θ, and the area ratio of the prism elements 211, 1140, and 1150. Thus, in the examples after this example, the description will be focused on various combinations of the direction of the refracting surface, the inclination angle θ, and the area ratio.

  As shown in FIG. 14, the projection image of the present embodiment is obtained with respect to the opening image 1400P (direct transmission image) and the opening image 1400P due to the light traveling straight without being refracted by the flat portions of the prism elements 1140 and 1150. The opening images 1400Pa, 1400Pb, 1400Pc, and 1400Pd are formed at positions separated by a distance S in the 45 ° direction indicated by the arrows. Thereby, the inside of the periodic region image 240P can be filled with the opening portion image without any gap. Further, the characteristic of this embodiment is that at least a part of four adjacent aperture images 1400Pa, 1400Pb, 1400Pc, and 1400Pd overlap each other in the black matrix image 220P to form a new aperture image 1410P. It is a point.

  As a result, a new opening image 1410P, which is an area where adjacent pixel portion images 1400P are formed overlapping each other, is at least image information of the first opening image 1400Pa and the second opening image 1400Pb that are adjacent to each other. Based on this, a new third aperture image can be formed. As a result, the density of the number of pixels to be projected can be improved.

  FIG. 15 is a diagram illustrating a projected image on the screen 116 of the projector according to the fourth embodiment. As shown in FIG. 15, the projected image of the present embodiment includes, for example, an opening image (direct transmission image) 1500P and an opening image 1500P due to light that travels straight without being refracted by the flat portions of the prism elements 1140 and 1150. On the other hand, opening images 1500Pa and 1500Pd are formed at positions separated by a distance S in the 45 ° direction indicated by the arrows. Thereby, the inside of the periodic region image 240P can be filled with the opening portion image without any gap. Further, the characteristic of this embodiment is that a substantially entire area between two adjacent opening image images 1500Pa and 1500Pd overlaps in the black matrix image 220P to form a new opening image 1510P. It is. Accordingly, a new third opening image can be formed based on the image information of the adjacent first opening image 1500Pa and the second opening image 1500Pd. As a result, the density of the number of pixels to be projected can be improved.

(Prism shape variation)
FIGS. 16-1 to 16-4 are diagrams illustrating examples of various variations of the shape of the prism element. For example, FIG. 16A shows a trapezoidal prism group 1610 having a refractive surface 1610a and a flat portion 1610b. FIG. 16-2 shows a three-type prism group 1620 having a refractive surface 1620a and a flat portion 1620b. FIG. 16C shows a three-type prism group 1630 having a refracting surface 1630a and a flat portion 1630b. FIG. 16-4 shows a blazed prism group 1640 consisting only of the refractive surface 1640a. As described above, various variations can be made using the direction of the refracting surface, the inclination angle, and the area as parameters.

  FIGS. 17A, 17-2, and 17-3 are plan views showing the positional relationship between the opening 1700 and the prism group 1710. As shown in FIG. 17-2, the direction along the side portion 1711a of each prism element 1711 makes about 45 ° with respect to the direction of the center line CL of the black matrix forming layer 203 shown in FIG. It is configured. As described above, the light transmitted through the one opening 1700 enters a part of the prism group 1710 including the plurality of prism elements 1711.

  Each prism element 1711 has a substantially square shape as shown in FIG. The prism element 1711 has a polygonal pyramid-shaped prism element, for example, a quadrangular pyramid-shaped refracting surface 1712a, 1712b, 1712c, 1712d. A flat portion 1713 is provided around the refracting surfaces 1712a, 1712b, 1712c, and 1712d.

  Next, a projected image on the screen 116 in the present embodiment will be described with reference to FIG. An aperture image (direct transmission image) 1700P is formed by the light transmitted through the flat portion 1713 of the prism element 1711. Then, an opening image 1720P that is a projection image in the direction of 45 ° with respect to the center line image CLP is formed by each of the refractive surfaces 1712a, 1712b, 1712c, and 1712d. In this embodiment, the inclination angles of the respective refracting surfaces 1712a, 1712b, 1712c, and 1712d are such that four projected images from the four adjacent opening portions 1700 are centered on the intersection point CP at the center of the four adjacent opening portion image 1700P. A new aperture image 1720P is formed so as to overlap with the position. Thus, by forming a new opening image 1720P, the apparent resolution can be improved 1.25 times in a pseudo manner.

  The prism element 1711 has a unit area T. Each refracting surface 1712a, 1712b, 1712c, and 1712d has an area T / 8, and the flat portion 1713 has an area 4T / 8. In this case, the amount of light of the opening portion image (direct transmission image) 1700P on the screen 116 is proportional to 4T / 8 = T / 2. Further, the amount of light forming the new aperture image 1720P is proportional to 4 × (T / 8) = T / 2. In this way, by controlling the area of each surface of the prism element 1711, the brightness of each projected image can be arbitrarily made substantially the same as in the present embodiment, for example. Thereby, a smooth and smooth image can be obtained.

  19A, 19B, and 19C are plan views showing the positional relationship between the opening 1900 and the prism group 1910. FIG. As shown in FIG. 19-2, the direction along the side portion 1911a of each prism element 1911 makes about 45 ° with respect to the direction of the center line CL of the black matrix forming layer 203 shown in FIG. It is configured. As described above, the light transmitted through one opening 1900 enters a part of the prism group 1910 including the plurality of prism elements 1911.

  Each prism element 1911 has a substantially square shape as shown in FIG. The prism element 1911 has a polygonal pyramid prism element, for example, a quadrangular pyramid-shaped refracting surface 1912a, 1912b, 1912c, 1912d. In addition, the flat part is not formed.

  Next, a projected image on the screen 116 in this embodiment will be described with reference to FIG. Each refracting surface 1912a, 1912b, 1912c, 1912d forms a projected image in the 45 ° direction with respect to the center line image CLP. In this embodiment, the refractive angles 1712a, 1712b, 1712c, and 1712d are set so that the four opening images 1912Pa, 1912Pb, 1912Pc, and 1912Pd, which are four projection images from the opening 1900, overlap in the periodic region image 240P. Projected without At this time, the prism element 1911 does not have a flat portion. For this reason, a projection image (shown by a dotted line in FIG. 20) due to a component that is directly transmitted through the prism element 1911 is not formed. Thus, there is no black matrix image, and a seamless and smooth image can be obtained.

  The prism element 1911 has a unit area T. Each refracting surface 1912a, 1912b, 1912c, 1912d has an area T / 4. In this case, on the screen 116, the aperture images 1912Pa, 1912Pb, 1912Pc, and 1912Pd can be made equal to each other, and the amount of light can be proportional to the area T / 4. Thereby, a smooth and smooth image can be obtained.

  FIG. 21 shows a schematic configuration in which a part of the prism group 2100 in Example 7 is enlarged. The prism group 2100 includes a first prism element 2110 having a quadrangular pyramid shape and a second prism element 2120 having a quadrangular pyramid shape. The first prism element 2110 is formed so that one side thereof forms approximately 45 ° with respect to the center line CL. The second prism element 2120 is formed so that one side thereof is substantially parallel to the center line CL. Further, a flat portion 2130 is provided around the first prism element 2110 and the second prism element 2120.

  Next, a projected image on the screen 116 in the present embodiment will be described with reference to FIG. An opening portion image (direct transmission image) 2200P is formed by the light transmitted through the flat portion 2130. Then, the refractive image 2111 of the first prism element 2110 forms an opening image 2111P in the 45 ° direction with respect to the center line image CLP. An aperture image 2121P is formed in a direction parallel to the center line image CLP by the refractive surface 2121 of the second prism element 2120. Then, the direction of the refracting surface and the inclination angle are set so that these projected images fill the black matrix image without gaps. Thereby, a smooth and smooth image can be obtained. Further, double density display can also be performed.

  The area ratio of the refracting surface is set with respect to the unit area T as an area T / 16 of the refracting surface 2111, an area 2T / 16 of the refracting surface 2121, and an area 4T / 16 of the flat portion 2130. Thereby, each light quantity of a projection image can be made substantially equal. Also, the shape of the prism group that produces the same refraction action as in the present embodiment can be variously modified. For example, a prism group 2300 having a refractive surface 2310 and a flat portion 2320 as shown in FIG. 23 can be used.

  FIG. 24 is a perspective sectional view of the liquid crystal panel 120R of the spatial light modulation device according to the eighth embodiment. In this embodiment, the configuration of the prism group 2400 is different from that of the first embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. The prism group 2400 is fixed to the TFT substrate 205 via the adhesive layer 2401 on the incident side. The prism group 2400 is fixed to the cover glass 2403 through an adhesive layer 2402 on the exit side.

  The configuration of the prism group 2400 of this example is shown in FIG. The refraction unit prism group 2400 includes two sets of prism elements 2410a and 2410b. The prism element 2410a has a substantially trapezoidal cross-sectional shape in the y-axis direction that is the first direction. The prism element 2410a has a longitudinal direction in the x-axis direction, which is the second direction substantially orthogonal to the y-axis direction, which is the first direction. Of the trapezoidal shape having a cross-sectional shape in the y-axis direction of the prism element 2410a, the two inclined surfaces Y1 and Y2 function as refractive surfaces. Of the cross-sectional shape of the prism element 2410a in the y-axis direction, the upper surface Y0 functions as a flat portion. For this reason, the light incident on the slope Y1 or the slope Y2 is refracted in a direction corresponding to the angle of the slope. A refracted transmission image is formed by the refracted light. Further, the light incident on the upper surface Y0 is transmitted as it is. A direct transmission image is formed by the light transmitted as it is.

  The prism element 2410b has the same configuration as the prism element 2410a. Of the cross-sectional shape of the prism element 2410b in the x-axis direction, the two inclined surfaces X1 and X2 function as refractive surfaces. Of the cross-sectional shape of the prism element 2410b in the x-axis direction, the upper surface X0 functions as a flat portion. The two sets of prism elements 2410a and 2410b are provided so that their longitudinal directions are substantially orthogonal to each other.

Further, in this embodiment, the plane side of the prism element 2410a and the plane side of the prism element 2410b are fixed facing each other. However, the present invention is not limited to this, and any one of the following configurations (1) to (3) may be used.
(1) A structure in which the surface on which the slopes Y1, Y2, etc. of the prism element 2410a are formed and the surface on which the slopes X1, X2, etc. of the prism element 2410b are formed face each other and are fixed.
(2) A configuration in which the surface of the prism element 2410a on which the inclined surfaces Y1, Y2, etc. are formed and the plane side of the prism element 2410b are faced and fixed.
(3) A configuration in which the flat surface side of the prism element 2410a and the surface on which the inclined surfaces X1, X2, etc. of the prism element 2410b are formed face each other and are fixed.
24 and 25, the prism surface is in contact with the structure. However, both surfaces may be in contact with air.

  FIG. 26 shows the splitting of incident light by the prism group 2400. In FIG. 26, incident light XY travels from the left side toward the right side. In addition, in a part of FIG. 26, for convenience of explanation, the light beam is specified using the symbols of the slopes Y0, Y1, and Y2. The incident light XY is branched into three light beams, a light beam Y1 and Y2 refracted on the inclined surface and a light beam Y0 that passes through the upper surface as it is, by a prism element 2410a indicated by a dotted line. The branched three light beams Y0, Y1, and Y2 are further branched into three light beams by the prism element 2410b. As a result, the incident light XY is branched into nine light beams Y1X1, Y1X0, Y1X2, Y0X1, Y0X0, Y0X2, Y2X1, Y2X0, and Y2X2.

  Next, the positions of the nine branched light beams on the projection plane will be described with reference to FIG. A region of a direct transmission image by the light ray Y0X0 is shown surrounded by a thick frame. Projected images of the pixel portion by the refracted light can be formed in directions orthogonal to the longitudinal directions of the prism elements 2410a and 2410b. In this embodiment, the two sets of prism elements 2410a and 2410b are configured so that the longitudinal directions thereof are substantially orthogonal to each other. As a result, a region of a refracted transmission image by the eight light beams Y1X1, Y1X0, Y1X2, Y0X1, Y0X2, Y2X1, Y2X0, and Y2X2 is formed around the region of the direct transmission image by the light beam Y0X0. In FIG. 27, each region is shown with a ray symbol. Further, the direct transmission image by the light beam Y0X0 is formed periodically adjacent to the positions of the plurality of openings 230 as shown in FIG. In this embodiment, the prism elements 2410a and 2410b form a refractive transmission image in a region between the direct transmission images of the light beam Y0X0. As a result, the observer does not recognize the black matrix portion image 220P (FIG. 4), which is a light shielding portion.

In this embodiment, the total light intensity from the upper surface Y0 of the prism element 2410a which is a flat portion of the screen 116 (FIG. 1) and the upper surface X0 of the prism element 2410b is PW0, and the inclined surfaces Y1 and Y2 which are refracting surfaces. When the total light intensity via X1 and X2 is PW1, respectively,
PW0 ≧ PW1
Is satisfied.

  The sum of the light intensities of the directly transmitted image by the light beam Y0X0 corresponds to the areas of the upper surfaces Y0 and X0 which are flat portions. Further, the sum of the light intensities of the refracted transmission images by the light rays Y1X1, Y1X0, Y1X2, Y0X1, Y0X2, Y2X1, Y2X0, and Y2X2 corresponds to the areas of the inclined surfaces Y1, Y2, X1, and X2 that are refracting surfaces. Here, if the total light intensity PW1 of the refracted transmission image by the light rays Y1X1, Y1X0, Y1X2, Y0X1, Y0X2, Y2X1, Y2X0, and Y2X2 becomes larger than the total light intensity PW0 of the direct transmission image, the observer Is recognized as a double image such as a ghost. For this reason, the image quality of the projected image is deteriorated.

  In the present embodiment, PW0 ≧ PW1 is satisfied. Therefore, the observer can observe an image that is seamless, smooth, and has a reduced feeling of roughness without recognizing the light-shielding portion around the direct transmission image that is the projection image of the original pixel portion. Furthermore, the observer does not recognize a deteriorated image such as a double image. Moreover, it is preferable that PW0> PW1 is satisfied. More preferably, it is desirable to satisfy PW0> 0.9 × PW1. As a result, the feeling of roughness can be further reduced seamlessly.

  Furthermore, the light intensity distribution of one section on the screen 116 (FIG. 1) which is the projection surface of the present embodiment will be described. FIG. 28A shows the light intensity distribution of the projected image on the screen 116. In FIG. 28A, the horizontal axis represents position coordinates on the screen 116, and the vertical axis represents an arbitrary intensity unit. For the sake of simplicity of explanation, the BB cross section passing through the approximate center of the three regions of the direct transmission image region I, the adjacent direct transmission image region K, and the region J between these regions shown in FIG. 27 will be described. To do. That is, the part indicated by reference numeral I on the horizontal axis in FIG. 28-1 corresponds to the area I in FIG. 27, the part indicated by reference numeral J corresponds to the area J in FIG. 27, and the part indicated by reference numeral K is the area in FIG. Corresponds to K.

  As shown in FIG. 28A, on the screen 116, the first peak value Pa of the intensity distribution of the region I and the region K of the projection image of the pixel portion formed by the light from the upper surfaces Y0 and X0 which are flat portions is The intensity distribution is larger than the second peak value Pb of the intensity distribution of the region J of the projected image of the pixel portion formed by the light passing through the inclined surfaces Y1, Y2, X1, and X2 that are refractive surfaces. For example, the second peak value Pb is set to a power distribution that is approximately half of the first peak value Pa. The power distribution of the light intensity can be controlled according to the area ratio between the upper surfaces Y0 and X0 of the prism elements 2410a and 2410b and the inclined surfaces Y1, Y2, X1 and X2.

  Further, in the region between the first peak value Pa and the second peak value Pb, the light intensity corresponds to a predetermined intensity distribution curve CV. Thereby, the observer recognizes an appropriate light intensity distribution in a region between the direct transmission image and the adjacent direct transmission image. For this reason, moderate intensity of light intensity is generated between adjacent pixel images, and an apparently high resolution image can be obtained. For this reason, the observer can observe a sharp projected image with reduced smoothness without recognizing the light shielding portion.

  Modified examples of the light intensity distribution are shown in FIGS. 28-2, 28-3, and 28-4, respectively. In FIG. 28-2, each of the two first peak values Pc of the light intensity distributions of the region I and the region K is larger than the second peak value Pc of the region J. 28C, the first peak value Pe of the light intensity distribution in the region I and the region K is larger than the two second peak values Pf in the region J. In FIG. 28-4, the first peak value Pg of each of the light intensity distributions in the region I and the region K is substantially the same as the second peak value Pg in the region J. When these power distributions are made, the recognition of the black matrix portion image 220P (FIG. 4) can be reduced, and a seamless and natural projection image can be obtained. Further, by changing the area ratio between the upper surface Y0, X0 and the slopes Y1, Y2, X1, X2 so that the light intensity distribution becomes a desired distribution curve, for example, a projected image with a tight and sharp impression can be obtained. You can also. For example, when projecting both a photographic image and a text image such as a character or a graph using a projector including the liquid crystal panel 120R of the present embodiment, the observer can observe both images with good image quality. .

  As described above, the spatial light modulation device according to the present invention is particularly useful for a liquid crystal spatial light modulation device.

1 is a schematic configuration diagram of a projector according to a first embodiment of the invention. 1 is a schematic configuration diagram of a liquid crystal panel of Example 1. FIG. 1 is a schematic diagram of a black matrix portion of Example 1. FIG. FIG. 3 is a schematic diagram of a black matrix image of Example 1. 1 is a cross-sectional view of a liquid crystal panel of Example 1. FIG. FIG. 3 is a layout diagram of openings according to the first embodiment. FIG. 3 is a layout diagram of prism groups according to the first embodiment. FIG. 3 is a diagram illustrating a shape of a prism according to the first embodiment. FIG. 3 is a diagram illustrating refraction in the prism element according to the first embodiment. FIG. 4 is a diagram for explaining a projected image according to the first embodiment. FIG. 6 is another diagram for explaining a projected image according to the first embodiment. FIG. 6 is still another diagram illustrating a projected image according to the first embodiment. FIG. 4 is a diagram for explaining a projected image according to the first embodiment. FIG. 6 is another diagram for explaining a projected image according to the first embodiment. FIG. 2 is a schematic diagram of an emission line spectrum of the extra-high pressure mercury lamp of Example 1. FIG. 6 is a schematic configuration diagram of a projector according to a second embodiment of the invention. FIG. 6 is a schematic configuration diagram of a prism group of Example 2. FIG. 6 is a schematic cross-sectional configuration diagram of a prism group of Example 2. FIG. 6 is a schematic diagram of a projected image of Example 3. FIG. 6 is a schematic diagram of a projected image of Example 4. The cross-sectional block diagram of the variation of a prism group. The other cross-sectional block diagram of the variation of a prism group. The other cross-sectional block diagram of the variation of a prism group. The cross-sectional block diagram of the variation of a prism group. FIG. 10 is a layout diagram of openings according to the fifth embodiment. FIG. 10 is a layout diagram of prism groups in Embodiment 5. FIG. 10 is a diagram illustrating a shape of a prism according to a fifth embodiment. FIG. 6 is a schematic diagram of a projection image of Example 5. FIG. 10 is a layout diagram of openings according to the sixth embodiment. FIG. 10 is a layout diagram of prism groups according to the sixth embodiment. FIG. 10 is a diagram illustrating the shape of a prism according to Example 6. FIG. 10 is a schematic diagram of a projected image of Example 6. FIG. 9 is a schematic diagram of a prism group of Example 7. FIG. 10 is a schematic diagram of a projected image of Example 7. Schematic of the modification of a prism group. FIG. 10 is a schematic configuration diagram of a liquid crystal panel of Example 8. FIG. 10 is a schematic configuration diagram of a prism group of Example 8. The figure explaining the branch of the light ray by refraction. Schematic of the refracted projection image. The figure which shows the light intensity distribution of a projection image. The figure which shows the other light intensity distribution of a projection image. The figure which shows other light intensity distribution of a projection image. The figure which shows the light intensity distribution of a projection image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Projector, 101 Super high pressure mercury lamp, 104 Integrator, 105 Polarization conversion element, 106R R light transmission dichroic mirror, 106GB B light transmission dichroic mirror, 107 Reflection mirror, 108 Relay lens, 110R Spatial light modulation device for 1st color light, 110G Spatial light modulator for second color light, 110B Spatial light modulator for third color light, 112 Cross dichroic prism, 112a, 112b Dichroic film, 114 Projection lens, 116 Screen, 120R, 120G, 120B Liquid crystal panel, 121R, 121G, 121B First polarizing plate, 123R, 123B λ / 2 retardation plate, 124R, 124B glass plate, 201 incident-side dustproof transparent plate, 202 counter substrate, 203 black matrix forming layer, 204 Liquid crystal layer, 205 TFT substrate, 206 Exit side dustproof transparent plate, 210 Prism group, 211 Prism element, 211a Side, 212 Refraction surface, 212a, 212b, 212c, 212d Refraction surface, 213 Flat portion, 220 Black matrix portion, 220P Black matrix image, 230 aperture, 230P aperture image, 230Pa, 230Pb, 230Pc, 230Pd aperture image, 240a surface, 240 periodic region, 240P periodic region image, 1100 projector, 1110 prism group, 1120a lower high refractive index Layer, 1120b lower low refractive index layer, 1120 first refractive layer, 1140 prism element, 1130 second refractive layer, 1130a upper high refractive index layer, 1130b upper low refractive index layer, 1150 prism element, 1400P aperture image 1400 Pa aperture image, 1400 Pb aperture image, 1410 P aperture image, 1500 Pa aperture image, 1500 P aperture image, 1500 Pd aperture image, 1510 P aperture image, 1610 prism group, 1610 a refracting surface, 1610 b flat portion, 1620 prism Group, 1620a refracting surface, 1620b flat portion, 1630 prism group, 1630a refracting surface, 1630b flat portion, 1640 prism group, 1640a refracting surface, 1700 aperture, 1700P aperture image, 1710 prism group, 1711 prism element, 1711a side , 1712a refracting surface, 1713 flat portion, 1720P aperture image, 1900 aperture, 1910 prism group, 1911 prism element, 1911a side, 1912Pa aperture image, 1912a refracting surface, 210 0 prism group, 2110 prism element, 2111P aperture image, 2111 refracting surface, 2120 prism element, 2121P aperture image, 2121 refracting surface, 2130 flat portion, 2200P aperture image, 2300 prism group, 2310 refracting surface, 2320 flat portion , CL center line, CLP center line image, CP intersection, CPa intersection, FS area, L distance, LL2 ray, La area, n refractive index, N normal, n1 refractive index, n2 refractive index, P1 total area, PT pitch , S distance, W1, W2 predetermined width, θ tilt angle, 2400 prism group, Y0, X0 top surface, Y1, Y2, X1, X2 slope, 2410a, 2410b prism element

Claims (10)

A modulator that modulates incident light according to an image signal and emits the modulated light;
A spatial light modulation device that is provided on an emission side of the modulation unit and includes a refraction unit that refracts light from the modulation unit;
The modulation unit includes a plurality of pixel units arranged in a matrix and a light shielding unit provided between the plurality of pixel units,
The refracting portion includes a prism group including a prism element including at least a refracting surface and a flat portion substantially parallel to the surface on which the pixel portion is formed,
Light from one of the plurality of pixel units is incident on at least some of the plurality of prism groups,
The refracting surface has a direction of the refracting surface that guides the projection image of the pixel unit onto the projection image of the light shielding unit, and the refracting surface and the optical axis on a projection surface that is a predetermined distance away from the refracting unit An angle formed with a reference plane formed in a substantially vertical direction,
Of the light from the pixel portion, the light transmitted or reflected by the flat portion travels substantially straight to form the projected image,
When the area occupied by one of the prism elements in the prism group is defined as a unit area, the ratio between the area of the refractive surface and the unit area corresponds to the light intensity of the projection image of the pixel unit,
The area of the flat portion and the area of the refractive surface are
PW0 is the sum of the intensities of light from the flat portion on the projection plane,
When the sum of the intensities of light passing through the refractive surface on the projection plane is PW1,
PW0 > PW1
A spatial light modulation device configured to satisfy the above. The pixel portion has a substantially rectangular shape,
The light-shielding portion has a shape in which band-shaped portions having a predetermined width are arranged in a lattice pattern,
The spatial light modulation device according to claim 1, wherein a direction along a side portion of the prism element is substantially 45 ° with respect to a direction of a center line of the light shielding portion. The pixel portion has a substantially rectangular shape,
The light-shielding portion has a shape in which band-shaped portions having a predetermined width are arranged in a lattice pattern,
3. The spatial light modulation device according to claim 1, wherein the prism group of the refracting portion is configured by a prism element having a polygonal pyramid shape having a flat portion in the vicinity of the apex portion of the cone.   4. The spatial light modulation device according to claim 3, wherein the prism group of the refracting portion is configured by a prism element having a substantially quadrangular pyramid shape having a flat portion in the vicinity of the apex portion of the cone. The pixel portion has a substantially rectangular shape,
The light-shielding portion has a shape in which band-shaped portions having a predetermined width are arranged in a lattice pattern,
The prism group of the refracting portion includes two sets of prism elements each having a substantially trapezoidal cross-sectional shape in a first direction and having a longitudinal direction in a second direction substantially orthogonal to the first direction, Two sets of prism elements are provided such that the longitudinal directions are substantially orthogonal to each other,
The spatial light modulator according to claim 1, wherein the trapezoidal slope corresponds to the refractive surface.   On the projection surface, the first peak value of the intensity distribution of the projection image of the pixel unit formed by the light from the flat portion is the value of the projection image of the pixel unit formed by the light passing through the refractive surface. The region between the first peak value and the second peak value that is larger than the second peak value of the intensity distribution is light intensity corresponding to a predetermined intensity distribution curve. The spatial light modulation device described. A light source unit that supplies light including first color light, second color light, and third color light;
A spatial light modulator for first color light that modulates the first color light according to an image signal;
A spatial light modulator for second color light that modulates the second color light according to an image signal;
A spatial light modulator for third color light that modulates the third color light according to an image signal;
The first color light modulated by the first color light spatial light modulation device, the second color light spatial light modulation device, and the third color light spatial light modulation device, the second color light, and the third color light, respectively. A color synthesis optical system for synthesizing color light;
A projection lens for projecting the light synthesized by the color synthesis optical system,
The spatial light modulator according to any one of claims 1 to 6, wherein the first color light spatial light modulator, the second color light spatial light modulator, and the third color light spatial light modulator. A projector characterized by being a device.   The spatial light modulation device for the first color light, the spatial light modulation device for the second color light, and the spatial light modulation device for the third color light each have the refracting portion. The projector according to 7.   The projector according to claim 7, wherein the refracting unit is provided on an incident side or an emission side of the color synthesis optical system.   The projector according to claim 7, further comprising a color separation optical system that separates light supplied from the light source unit into the first color light, the second color light, and the third color light.

Images