JP2005326573A - Rear projection image display apparatus and/or rear projection screen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a displayed image high in image quality by eliminating such a failure that adjacent optional displayed pixel images partially overlap each other in a rear projection image display apparatus. <P>SOLUTION: A V-shaped groove G is formed near a boundary between a pixel display area 1 and a pixel display area 2 on the light incident surface Sa of the rear side of the rear projection screen S. The light 2 entering the area 2 in a conventional manner is partially reflected by a surface 2 as shown by a continuous line. Non-reflected components enter the area 2 through the surface 2, but, the reflectance can be enhanced by increasing the incident angle on the surface 2. When comparing the incident angle θ1 of the light 2 on the surface 2 with the incident angle θ2 of the light 2 on the surface 1 as an inclined surface after being reflected by the surface 2, θ1> θ2 is established. Then, the light 2 made incident on the surface 1 hardly reflects from the surface 1 and enters the area 1. Besides, the incident angle θ3 of the light 1 which is not made incident on the surface 2 but made incident on the surface 1 on the surface 1 is smaller than the incident angle θ1, then, the light 1 hardly reflects from the surface 1, and then, enters the area 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rear projection type image display apparatus such as a liquid crystal projector using a spatial light modulator.

In a projector apparatus that projects a display image on a panel of a spatial light modulation element (hereinafter referred to as a light valve) onto a screen using an enlargement optical system, the resolution of the projection image is increasing due to an increase in the number of pixels of the projection image. .
The most common method for increasing the definition of a projected image is to increase the number of pixels of the light valve. When the number of pixels of the light valve is increased, the pixel display area on the screen is reduced. Therefore, the resolution performance required for the projection optical system is increased, and a resolution characteristic in a high frequency band is required.
As the pixel display area becomes smaller, it becomes difficult to take measures against the phenomenon that an image stroke between adjacent pixel display areas, that is, a part of display light enters the adjacent pixel display area.
In order to increase the number of pixels without changing the size of the light valve, it is necessary to reduce the size of one pixel. This affects the cost increase of the light valve.
In order to increase the number of pixels without reducing the pixel size, the area of the light valve may be increased. However, it is difficult to increase the area of the light valve and reduce the illumination optical system and the projection optical system. It is important to reduce the size and weight of the projection device, and the size of the light valve is reduced.

There has also been proposed a special display method in which the number of pixels of an image to be enlarged and projected is apparently increased without changing the size of the light valve and without increasing the number of pixels of the light valve.
This is a method of projecting and displaying the light valve pixel projection position with a slight shift. Hereinafter, this method is referred to as a pixel shift display method.
This is a time-division display in which the position for enlarging and displaying pixels on the spatial modulation element is shifted by about one pixel or less by optical means or the like, and different image information is given to each pixel displayed by shifting as necessary. Thus, it is a method of displaying more pixels than the number of pixels of the spatial modulation element apparently. In addition to the time-division display method, a plurality of image projection devices are used to divide a piece of image information into a plurality of images, and the divided images are superimposed on the same projection plane, and the projection positions are shifted to each other. There is also a method of projecting so that the pixels are shifted.
In order to perform the pixel-shifted display method, display information of one frame when pixel-shifted display is not performed is divided into two or more subframe display information. The display information of the divided subframes is projected with the display position slightly shifted.
As described above, as described above, there are a method in which a plurality of different screens configured by a plurality of subframes are statically superimposed and projected, and a method in which these are projected and displayed in a time division manner.
The amount of movement of the projection pixel should be smaller than the projection pixel size. It is preferable to shift about 1/2 of the projected pixel.

As a method of shifting the projection position of the pixel, in the case of static superimposed projection display, there is a method of projecting sub-frame images each divided by using a plurality of projection devices. In the case of dynamic time-division projection display, the sub-frame image is time-divisionally projected and displayed using active pixel shifting means.
In the case of time-division projection display, the projection position of the image is moved on the projection plane at a speed higher than the frequency at which the image is displayed. Assuming that the standard frame frequency is 60 Hz, the display frequency of each subframe is 120 Hz when divided into two subframes and displayed by alternately shifting the pixels. Similarly, when the display is divided into four subframes and the pixels are alternately shifted and displayed, the display frequency of each subframe is 240 Hz.

As a method for moving the display position of the image, for example, a laminated component of a light transmissive substrate, an ITO electrode layer, a liquid crystal layer, an ITO electrode layer, and a light transmissive substrate is placed in the optical path of the projection system, and ITO is placed on the liquid crystal layer. There is a method in which an electric field is applied by an electrode to electrically switch the alignment direction of the liquid crystal, and the optical path passing through the liquid crystal layer is parallel-shifted by a birefringence effect.
By switching the direction of the long axis of the vertical alignment type ferroelectric liquid crystal so that it is tilted to ± with respect to the optical axis in the plane including the optical axis, the emission position of the light beam passing through the liquid crystal layer is changed to the optical axis. Can be shifted to ± in the plane including the. Details of such pixel shifting elements are described in Japanese Patent Application Laid-Open No. 2002-214579, and are omitted here. Pixel shift display is also possible by other methods, and there are many disclosed examples.

As a method of optically displacing an image of a spatial light modulator (for example, a liquid crystal element) for each pixel and projecting an image having a resolution higher than that of the spatial light modulator, Japanese Patent Laid-Open No. 4-113308 (Japanese Patent No. 293926) is disclosed. JP-A-5-289044, JP-A-9-152572, JP-A-6-324320, JP-A-2000-98968, and the like.
These can be achieved on the screen by changing the subfield to be displaced by 2 or 4 by optically displacing the pixel by optical axis shift at two positions perpendicular to the scanning line, or at four vertical and horizontal positions. It is said that it is possible to obtain double and quadruple resolutions, respectively.

  JP-A-8-194207, JP-A-9-230329, JP-A-9-015548, and the like disclose that one direction is achieved by controlling the pixel arrangement, the displacement amount and the displacement direction of the optical axis shift. The RGB pixels, which are spatially divided by the filter, are overlapped with the three positions displaced in the same direction to improve the resolution by a factor of 3, or by shifting to realize an RGB delta arrangement. An apparatus is also disclosed in which only a specific pixel is shifted to increase the resolution only in a specific portion.

By the way, when the pixels of the light valve are projected and displayed, the ideal display area size of the pixel image of the light valve that is projected and displayed is pixel size × projection magnification in a normal projector apparatus. At this time, the images of adjacent pixels are projected with almost no gap. Strictly speaking, since there is a gap between the pixels of the light valve body, the gap area is displayed in black, but the area displayed in black is much thinner than the pixels. If pixel-shifted display is performed in this state, the images of adjacent pixels that are displayed partially overlap.
As shown in FIG. 19, in a state where two pixels are displayed with a shift of ½ pitch of the pixel size, some of the two pixels overlap as shown in FIG. The overlapping area is hatched. In such a display state, the CTF value deteriorates, and an image with a blurred outline / edge is obtained depending on the image pattern. The blurring of the outline is particularly noticeable where the image has a large difference in shading. This blur is noticeable when displaying images with conspicuous edges such as characters and drawings.

As a method of improving the above-described image blur, there is a method of reducing the size of the pixel of the light valve projected onto the projection plane. This method is hereinafter referred to as a pixel reduction display method.
Here, the pixel reduction display method does not reduce the size of the entire projection screen, but reduces only the size of the display image on the projection surface of the light valve pixels without changing the size of the entire screen. Is a special display method. Since only the size of the projected image of the pixel is reduced and displayed, adjacent pixel images are projected with a gap.
As shown in FIG. 21, when the pixels of the spatial modulation element are reduced and the image is enlarged and projected, the size of the enlarged and projected pixel image is smaller than in the example shown in FIG. Assuming that the pixel reduction ratio is 0.5, the size of the pixel to be enlarged and projected is ½ of the conventional size. Therefore, the pixel shift equivalent to this pixel size, that is, the pixel size in FIG. 22, there is almost no overlap between the two pixel images as shown in FIG.

In this way, by using the pixel reduction display method together and performing pixel-shifted display with a movement amount equivalent to a half pixel, the problem of overlapping of adjacent pixel images can be almost solved, thereby causing blurring of the image. Has been thought to be reduced.
Japanese Patent Application Laid-Open No. 4-113308 discloses a configuration of a spatial light modulator having pixels whose pixel size is smaller than 1/2 the pixel pitch, and a projection image in which the resolution is increased by using this and pixel shifting means. A forming apparatus is disclosed. In addition, the overlap between adjacent pixels is not pointed out here.

  Japanese Patent Application Laid-Open No. 9-054554 discloses a method of condensing light with a condensing lens smaller than the opening of the transmissive liquid crystal panel when the resolution is increased by the pixel shifting means. As means for changing the pixel size, a configuration in which a microlens is combined with a transmissive liquid crystal panel is shown. An active element is provided to face a pixel (opening) of a transmissive liquid crystal light valve having an opening having a predetermined shape size. The active element reduces the overall aperture. In order to reduce the pixel size further than the opening, a microlens having a circular outer shape is provided here. In addition, a projection enlargement device using a liquid crystal light valve and a pixel shifting element increases the resolution twice in one direction, and a display image is constructed using a condensing optical system group corresponding to each pixel opening of the light valve. An example of reducing the size of each pixel is shown. Note that details of the light intensity distribution forming the pixels are not described here.

JP-A-4-113308 Japanese Patent Laid-Open No. 5-289044 JP-A-9-152572 JP-A-6-324320 JP 2000-98968 A JP 2002-214579 A JP-A-8-194207 Japanese Patent Laid-Open No. 9-230329 Japanese Patent Laid-Open No. 9-015548 JP-A-9-055454 JP 2003-177475 A JP 2003-144481 A JP-A-5-072634

However, as will be described later, when the pixel reduction means is added, the explanation that the overlap between display pixels immediately disappears is actually insufficient. This is because the image quality is not the same regardless of the light intensity distribution profile of each display pixel when pixel reduction display is performed.
As described in JP-A-4-113308, when a projection lens having a high MTF is used, the resolution becomes high, but visibility problems such as “jaggy” become obvious.
If the MTF of the projection lens is made relatively low at this time, “jaggy” or the like becomes inconspicuous, but “sharpness” is greatly reduced. As a result, high-resolution video projectors and high-resolution data projectors are originally aimed. Image characteristics cannot be formed by pixel shifting means. That is, it is not sufficient to use only the pixel shifting means, and it is not sufficient to reduce the pixels.

Further, when performing high-resolution image display using the pixel reduction technique and the pixel shifting technique, there are the following problems.
In order to display a high-resolution image using the pixel shifting technique, it is important to consider the pixel display area on the screen. For example, when displaying a pixel that is four times as large as a normal pixel by using the pixel shifting technique, it is preferable that the display area of one pixel is 1/4 of the conventional one. If it exceeds 1/4, crosstalk occurs with the pixel image of the adjacent pixel display area.
When the pixel reduction ratio is increased, the displayed pixel image is reduced, so that crosstalk can be avoided, but the following problems occur.

When a pixel image is displayed small, the continuity of pixel images in adjacent pixel display areas becomes conspicuous. Light forming an image of a pixel in an arbitrary pixel display area has a light intensity distribution with a bright center and a dark periphery. For this reason, as the pixel reduction rate is increased, the peripheral portion of the pixel display area becomes darker.
For example, when white is displayed in two adjacent pixel display areas, a slightly dark area is formed near the boundary between the pixel display areas, and the smoothness of the displayed screen deteriorates.

When trying to display a pixel image small, it is effective to increase the condensing NA of the microlens array used as the pixel reduction means. At this time, the curvature radius of the curved surface of the microlens is reduced. When the radius of curvature is reduced, the polarization characteristics of the illumination light incident on the microlens change. This is a phenomenon called depolarization phenomenon.
For example, when transmitting S-polarized linearly polarized light to a microlens, the transmitted light has a P-polarized component if the radius of curvature of the microlens is small. When the P-polarized component is generated, the polarization state of the image generation light modulated by the light valve is also affected, and the contrast is lowered.
For this reason, it is not desirable from the viewpoint of contrast performance to make the radius of curvature of the microlens excessively small.
However, unless the radius of curvature of the microlens is reduced, as described above, light spreads outside the pixel display area on the screen surface, and adjacent pixel images will crosstalk.

For the crosstalk of the pixel image as described above, there is almost no precedent for effective countermeasures by the screen structure.
Many rear projection screens have a Fresnel lens surface on the projection side and a lenticular lens array surface laminated. The purpose of the Fresnel surface is to deflect the projected light in the normal direction of the screen, and the lenticular lens array has a divergence angle when the light deflected by the Fresnel surface is viewed from the viewer side, that is, a screen gain adjustment function. Have
Alternatively, there is a configuration in which light is emitted by mixing beads in the screen layer. However, with these configurations, crosstalk between adjacent pixel images on the screen cannot be avoided.
There are known examples in which the above-mentioned Fresnel pitch or lenticular pitch is defined, but this is intended to avoid the occurrence of moire.
Alternatively, the stray light incident on any pixel image display area on the screen is escaped away from the pixel display area, or the stray light is absorbed by the light absorption layer, so that the pixel image becomes a double image. Although there is a known example that avoids the problem, this method involves a loss of light amount.

With these screen technologies, it is impossible to return to a desired pixel display area without losing a crosstalk component between adjacent pixel display areas.
As described above, even if the number of display pixels is simply increased, a good image cannot be obtained unless pixel crosstalk is eliminated.
When displaying with shifted pixels, increasing the pixel reduction ratio lowers the contrast and degrades the smoothness of the image, and lowering the pixel reduction ratio causes crosstalk and sharpness deterioration. There's a problem.
Even when the pixel shift display method and the pixel reduction display method are not performed, there is a problem of crosstalk between arbitrary adjacent pixel display areas on the screen.

  Accordingly, the main object of the present invention is to provide a rear projection type image display apparatus that can eliminate the problem that adjacent arbitrary display pixel images partially overlap and can improve the image quality of the display image.

  In order to achieve the above object, the invention according to claim 1 includes at least an illumination light source, a spatial light modulation element having a plurality of pixels, an enlarged projection optical system, and a rear projection screen, and the spatial light modulation. In the image display device in which the image of the pixel of the element is enlarged and displayed on the projection surface of the rear projection screen by the enlargement projection optical system, the pixel image is inclined near the region boundary of the arbitrary pixel display region on the rear surface of the rear projection screen. It has a groove with a surface.

According to a second aspect of the present invention, at least an illumination light source, a spatial light modulation element having a plurality of pixels, pixel reduction means for generating a reduced image of the pixels, and pixel shifting means for shifting the projection position of the reduced image An enlarged projection optical system and a rear projection screen, and the reduced pixel image is enlarged and projected onto the projection surface of the rear projection screen by the enlarged projection optical system, and displayed on the image plane by the pixel shifting means. In the image display device in which the position of the image of the pixel to be displayed is shifted, a groove having an inclined surface is provided in the vicinity of a region boundary of an arbitrary pixel display region on the rear surface of the rear projection screen. .
Here, in particular, it is intended to solve the problem that adjacent display pixel images partially overlap when a pixel-shifted display is performed with pixel reduction means.

According to a third aspect of the present invention, in the rear projection type image display device according to the first or second aspect, in an arbitrary pixel display region 1 and a pixel display region 2 adjacent to the pixel display region 1 in the rear projection screen. The inclined surface of the groove is in at least one of the pixel display region 1 and the pixel display region 2, and the inclined surface selects a light ray component that generates an image of the pixel display region without the inclined surface. The light beam component that selectively reflects and generates the image of the pixel display area having the inclined surface is selectively transmitted.
Here, in particular, when pixel-shifted display is performed, crosstalk of light to any pixel display area adjacent to any pixel display area on the rear projection screen is prevented, and adjacent pixel display is performed when pixel-shifted display is performed. The object is to prevent the pixel images in the region from overlapping each other.

According to a fourth aspect of the present invention, in the rear projection image display device according to the third aspect, the boundary surface in the screen thickness direction of any adjacent pixel display region in the region deeper than the depth of the groove is a light reflecting layer. It is characterized by being.
In particular, the object is to prevent leakage of light rays, which are selectively separated by the inclined surfaces of the grooves and guided into a desired pixel display area, to adjacent pixel display areas.

According to a fifth aspect of the present invention, in the rear projection type image display device according to the fourth aspect of the present invention, a light diffusion layer parallel to the light incident surface of the rear projection screen at a position deeper than the groove in an arbitrary pixel display region. Is provided.
Here, in particular, an object is to make the light intensity distribution in the pixel display region uniform.

According to a sixth aspect of the present invention, in the rear projection type image display device according to the fifth aspect, the light reflecting layer is continuous above and below the screen thickness direction of the light diffusing layer.
Here, in particular, it is intended to prevent leakage of light rays that have lost directivity due to the light diffusing layer to adjacent pixel display areas.

The invention according to claim 7 is the rear projection type image display device according to claim 1 or 2, wherein the inclined surface of the groove has a positive curvature.
In particular, the object is to reduce the difference in reflectance of the light beam with respect to the incident position of the inclined surface of the groove.

According to an eighth aspect of the present invention, in the rear projection type image display device according to the first or second aspect, an inclination angle φ2 (X of the groove) at an arbitrary coordinate (X, Y) on a light incident surface of the rear projection screen. , Y) is larger than the light incident angle φ1 (X, Y) with respect to the screen normal at the same position.
Here, in particular, when the rear projection is performed obliquely with respect to the normal line of the rear projection screen, the object is to prevent the crosstalk of the pixel image from occurring at an arbitrary position on the rear projection screen.

According to a ninth aspect of the present invention, in the rear projection type image display device according to the first or second aspect, the groove is sealed with a sealing material, and the refractive index N2 of the sealing material is the refraction of the rear projection screen. It is characterized by being larger than the rate N1.
In particular, the object is to improve the reflection / transmission separation characteristics depending on the light incident angle on the inclined surface of the groove.

According to a tenth aspect of the present invention, in the rear projection type image display device according to the first or second aspect, the incident angle of the light beam 1 that should enter an arbitrary pixel display area 1 with respect to the inclined surface is ψ1, and the pixel display area When the incident angle of a light beam 2 that should enter an arbitrary pixel display area 2 adjacent to 1 is ψ2, the inclined surface reflects the light beam 1 and transmits the light beam 2 It has an angle.
Here, in particular, the object is to define and optimize the relationship between the angle of the inclined surface in the groove and the light incident angle.

According to an eleventh aspect of the present invention, in the rear projection image display device according to the tenth aspect, the light beam 1 is a light beam having a minimum incident angle at an arbitrary incident position on the inclined surface.
In the case of a lamp light source, the incident angle of a light beam incident at an arbitrary position on an inclined surface is not uniquely determined. Therefore, it is specified what incident angle of light beam is selected for reflection / transmission. There is a need to. The purpose here is to optimize it.

According to a twelfth aspect of the present invention, in the rear projection type image display device according to the first or second aspect, in the adjacent pixel display region, the groove is formed in a region including a part of the pixel display region. There are two inclined surfaces, the first inclined surface is in the first pixel display area, and the second inclined surface is in the second pixel display area, and each inclined surface is inclined. The angle is different.
Here, in particular, in the pixel display area 2 on the back surface of the rear projection screen, the light beam that should reach the adjacent pixel display area 1 is guided to the pixel display area 1 and also to the pixel display area 1 on the back surface of the rear projection screen. Therefore, an object is to guide a light beam that should reach the adjacent pixel display area 2 to the pixel display area 2.

According to a thirteenth aspect of the present invention, in the rear projection type image display device according to the twelfth aspect, the center of an arbitrary pixel display area and the center position of a spot of a light beam that generates an image in the pixel display area are shifted. Features.
With the inclined surface 1 provided on the display area 1 side, it is difficult to sufficiently reflect and transmit and separate the light beam reaching the display area 1 and the light beam reaching the display area 2. The purpose here is to eliminate this problem.

According to a fourteenth aspect of the present invention, in the rear projection type image display device according to the thirteenth aspect, with respect to the center of an arbitrary pixel display region, the center position of the spot of the light beam that generates the image of the pixel display region is In the right area from the center of the rear projection screen, it is shifted in the lower left direction, and in the left area from the center of the rear projection screen, it is shifted in the lower right direction.
Here, in particular, an object is to optimize by specifying the positional relationship between individual pixel display areas and pixel image generation light beam spots on the rear projection screen surface.

According to a fifteenth aspect of the present invention, in the rear projection type image display device according to the first or second aspect, the groove has two surfaces, and one surface of the two surfaces is an inclined surface, and the other surface is the other surface. The surface is a surface perpendicular to the light incident surface of the rear projection screen.
Here, in particular, the object is to improve the light separation characteristics and simplify the structure of the grooves.

According to a sixteenth aspect of the present invention, in the rear projection type image display device according to the fifteenth aspect, the groove has a connecting surface that connects the inclined surface and the vertical surface.
Here, it aims at making it the groove | channel shape excellent in manufacture ease especially.

  In a seventeenth aspect of the present invention, a rear projection screen used in the rear projection type image display device has a groove having an inclined surface in the vicinity of a region boundary of an arbitrary pixel display region on the rear surface.

  According to the first aspect of the present invention, at least an illumination light source, a spatial light modulation element having a plurality of pixels, an enlarged projection optical system, and a rear projection screen are provided, and an image of the pixel of the spatial light modulation element is In the image display device that is enlarged and displayed on the projection surface of the rear projection screen by the enlargement projection optical system, a groove having an inclined surface is provided in the vicinity of an area boundary of an arbitrary pixel display region on the rear surface of the rear projection screen. Therefore, the problem that adjacent pixel images partially overlap can be solved, and an image without image blur can be displayed.

  According to the second aspect of the present invention, at least an illumination light source, a spatial light modulation element having a plurality of pixels, pixel reduction means for generating a reduced image of the pixel, and pixel shifting for shifting the projection position of the reduced image. Means, an enlarged projection optical system, and a rear projection screen. The reduced pixel image is enlarged and projected onto the projection surface of the rear projection screen by the enlarged projection optical system, and on the image plane by the pixel shifting means. In the image display device in which the position of the image of the pixel displayed on the screen is shifted, a groove having an inclined surface is provided in the vicinity of the region boundary of the arbitrary pixel display region on the rear surface of the rear projection screen. Therefore, with the pixel reduction means, it is possible to eliminate the problem that adjacent pixel images partially overlap when displayed while shifting pixels, and an image without image blur can be displayed.

  According to a third aspect of the present invention, in the rear projection type image display device according to the first or second aspect, an arbitrary pixel display region 1 and a pixel display region adjacent to the pixel display region 1 on the rear projection screen. 2, the inclined surface of the groove is in at least one of the pixel display region 1 and the pixel display region 2, and the inclined surface is a light ray component that generates an image of the pixel display region without the inclined surface. Is selectively transmitted, and the light ray component that generates the image of the pixel display region having the inclined surface is selectively transmitted, so that the pixel display region 2 adjacent to the arbitrary pixel display region 1 is entered. The light component that has been reflected can be reflected and deflected on the inclined surface of the groove and guided into the pixel display region 1. Thereby, when the pixel is shifted and displayed, the crosstalk of the pixel image in the adjacent pixel display area can be eliminated.

  According to a fourth aspect of the present invention, in the rear projection type image display device according to the third aspect, the screen thickness direction boundary surface of any adjacent pixel display region in the region deeper than the depth of the groove reflects light. Since it is a layer, the light beam guided from the adjacent pixel display area to the normal pixel display area is reflected by the light reflection layer and does not leak to the adjacent pixel display area.

  According to a fifth aspect of the present invention, in the rear projection type image display device according to the fourth aspect, light is emitted parallel to the light incident surface of the rear projection screen at a position deeper than the groove in an arbitrary pixel display region. Since the diffusion layer is provided, the directivity of the light beam can be weakened by the light diffusion layer, and the light intensity distribution in the pixel display region is made uniform.

  According to the invention of claim 6, in the rear projection type image display device according to claim 5, the light reflection layer is continuous up and down in the screen thickness direction of the light diffusion layer. The light beam that has lost its directivity is completely reflected by the light reflecting layer, does not cross-talk to the adjacent pixel display area, and is displayed in a pixel-shifted manner, thereby eliminating the problem that adjacent pixel images partially overlap.

  According to the seventh aspect of the present invention, in the rear projection type image display device according to the first or second aspect, since the inclined surface of the groove has a positive curvature, the reflection by the incident position of the inclined surface of the groove. Since the rate difference is reduced, the efficiency of capturing light rays in the region 1 away from the region 1 increases, and the pixels in the region become brighter.

  According to an eighth aspect of the present invention, in the rear projection type image display device according to the first or second aspect, the groove inclination angle φ2 at an arbitrary coordinate (X, Y) on the light incident surface of the rear projection screen. Since (X, Y) is larger than the light incident angle φ1 (X, Y) with respect to the screen normal at the same position, rear projection is performed by changing the inclination angle of the groove according to the position on the rear projection screen. When projecting obliquely on the screen, an effect of preventing crosstalk can be obtained at an arbitrary position on the rear projection screen.

  According to a ninth aspect of the present invention, in the rear projection type image display device according to the first or second aspect, the groove is sealed with a sealing material, and the refractive index N2 of the sealing material is determined by the rear projection screen. Therefore, when light is reflected on the inclined surface of the groove, total internal reflection occurs and the reflectance is improved. Also, the reflection / transmission separation characteristics depending on the incident angle are improved.

  According to a tenth aspect of the present invention, in the rear projection type image display device according to the first or second aspect, the incident angle of the light beam 1 that should enter an arbitrary pixel display region 1 with respect to the inclined surface is ψ1, and the pixel When the incident angle of a light beam 2 to enter an arbitrary pixel display region 2 adjacent to the display region 1 with respect to the same inclined surface is ψ2, the inclined surface reflects the light beam 1 and transmits the light beam 2. Therefore, the light rays in the arbitrary pixel display area 2 adjacent to the arbitrary pixel display area 1 on the back surface of the rear projection screen can be selectively reflected and guided to the pixel display area 1. .

  According to the eleventh aspect of the present invention, in the rear projection type image display device according to the tenth aspect, the light beam 1 is a light beam having a minimum incident angle at an arbitrary incident position on the inclined surface. If reflection / transmission selectivity is obtained with respect to the light beam under the above conditions, the reflection / transmission selection is correctly performed for other light beams.

  According to a twelfth aspect of the present invention, in the rear projection type image display device according to the first or second aspect, in the adjacent pixel display region, the groove is formed in a region including a part of the pixel display region, The groove has two inclined surfaces, the first inclined surface is in the first pixel display area, and the second inclined surface is in the second pixel display area. Since the inclination angles are different from each other, it is possible to obtain a reflection action for returning the light beam shifted to the pixel display region 1 side to the pixel display region 2.

  According to a thirteenth aspect of the present invention, in the rear projection type image display device according to the twelfth aspect, the center of an arbitrary pixel display area is shifted from the center position of a spot of a light beam that generates an image in the pixel display area. Since the spot of the light flux in the pixel display area 2 leaks to the pixel display area 3 but does not leak to the pixel display area 1 side, the center position of the spot is set to the center position of the pixel display area. It is not necessary to return the light beam leaking to the pixel display region 1 side to the pixel display region 2 by shifting from the pixel display region 1 side.

  According to the fourteenth aspect of the present invention, in the rear projection type image display device according to the thirteenth aspect, with respect to the center of an arbitrary pixel display area, the center position of the spot of the light beam that generates the image of the pixel display area is In the right area from the center of the rear projection screen, it is shifted to the lower left direction, and in the left area from the center of the rear projection screen, it is shifted to the lower right direction. Can be separated and led to a desired pixel display region.

  According to the invention described in claim 15, in the rear projection type image display device according to claim 1 or 2, the groove has two surfaces, and one surface of the two surfaces is an inclined surface, Since the other surface is a surface perpendicular to the light incident surface of the rear projection screen, it is easy to manufacture.

  According to a sixteenth aspect of the present invention, in the rear projection image display device according to the fifteenth aspect, since the groove has a connecting surface that connects the inclined surface and the vertical surface, the manufacturing is further facilitated. It becomes. When grooving, the effect on the light separation characteristics is small unless the width of the connecting surface is significantly increased.

  According to the invention of claim 17, in the rear projection screen used in the rear projection type image display device, since it has a groove with an inclined surface in the vicinity of the region boundary of an arbitrary pixel display region on the rear surface, The problem that adjacent pixel images partially overlap can be solved, and an image without image blur can be displayed.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
First, an outline of the configuration of the rear projection type image display apparatus in the present embodiment will be described.
The illumination light generated from the lamp light source is unpolarized white light. The spatial distribution of illuminance is made uniform by using a fly-eye lens array or a rod integrator. Next, this is converted into linearly polarized light by a polarizing plate. Next, the illumination light is reflected by the polarization separation element. A typical example of the polarization separation element is a polarization beam splitter. The reflected illumination light is passed through the skew correction plate. Next, it is separated into three colors of RGB by a color separation prism.
From this point onward, since the optical paths are separated into RGB three colors, one of the optical paths will be described. The color-separated illumination light is passed through the pixel reduction means. Next, the pixel surface of a reflective light valve as a spatial light modulator is irradiated. The illumination light is reflected. This reflected light is again passed through the pixel reduction means. In this process, the illumination light conveniently passes through the pixel reduction means twice.

Here, since the pixel reduction means wants to generate a pixel reduced image for each of the pixels of the light valve, it is set to correspond to each of the plurality of pixels on a one-to-one basis. When passing through the pixel reducing means for the first time, the illumination light is slightly condensed. Thereby, the illumination light illuminates a part including the center, not the entire pixel of the light valve.
Further, the illumination light is also condensed when the illumination light reflected from the light valve passes through the pixel reduction means for the second time. In this way, the light beam that illuminates one pixel is brought into a narrowed state. Since the aperture is narrowed, the cross section of the light beam can be smaller than the pixel. This state is referred to as a pixel reduced image. Such a reduced pixel image is made for all pixels.

The light flux is once diverged and then again shifts to a divergent state. The illumination light that has shifted to the diverging state is passed through the skew correction plate described above. Here, the illumination lights of the three colors returned from the three optical paths are synthesized by the color synthesis prism. Next, the synthesized illumination light is passed through the wave plate. This wave plate is provided so as to satisfy the arrangement condition of the polarizing plate and the crossed Nicols.
The illumination light that has passed through the wave plate is passed through the pixel shifting means. As the pixel shifting means, a pixel shifting means having an optical path shift function using liquid crystal has been proposed so far, and this can be used. The illumination light that has passed through the pixel shifting means is passed through the magnification projection optical system. The enlarged image is projected and displayed on the screen through the magnifying projection optical system via the folding mirror.

Next, a specific example of the configuration of the rear projection type image display apparatus according to this embodiment will be described with reference to FIG.
The illumination light emitted from the lamp light source 31 passes through the UV cut filter 32 and the IR cut filter, and the spatial distribution of illuminance is made uniform by the two microlens array plates 34.
Thereafter, the illumination light is optically separated by the color separation filter 35 and deflected by the mirror 36. Reference numerals 37 and 38 denote lenses for correcting two optical path lengths separated from each other, and reference numeral 39 denotes a color separation filter. The illumination light is converted into linearly polarized light by the half-wave plate 40 and enters the polarization beam splitter 41.
Reference numeral 42 denotes an element in which a reflective light valve element and an image reduction element are integrated, and reference numeral 43 denotes a magnification chromatic aberration correction lens.
The illumination light separated into RGB by the color separation filters 35 and 39 is color-synthesized by the cross prism 44. Illumination light exiting the cross prism 44 passes through a retarder polarizer 45, a pixel shifting element 46 having a pixel shifting function in the X direction, a pixel shifting element 47 having a pixel shifting function in the Y direction, and an enlarged projection optical system 48. Through to a projection surface (not shown). A folding mirror (not shown) is provided at the subsequent stage of the magnifying projection optical system 48, and a rear projection screen (hereinafter also referred to simply as “screen”) to be described later is disposed at the subsequent stage.

In the above configuration and illumination light path conditions, as a configuration example of the reflective light valve element, a configuration in which a pixel surface, a liquid crystal layer, and a cover glass layer are stacked on a silicon backplane is known. The liquid crystal layer and the microlens array substrate are bonded via an adhesive layer. The microlens array functions as a pixel reduction unit as described below.
A plurality of microlenses are arranged on the microlens array substrate, which are arranged in one-to-one correspondence with the plurality of pixels of the reflective light valve element, and the optical axis of the microlens The centers of the pixels are configured to match.
Here, the opening shape of the microlens is a square. The focal length of the microlens is preferably longer than twice the distance from the principal point of the microlens to the pixel surface. In this way, when the illumination light is guided from the microlens side, the illumination light passes through the microlens and becomes a condensing spot to irradiate the pixel. The illumination light that irradiates the pixel is reflected by the pixel, passes through the microlens, and is further condensed.

Since the illumination light generated from the lamp light source 31 is a light beam composed of a light beam component in a predetermined angle range, the light beam at the condensing position is not completely condensed at one point, and has a finite size.
Therefore, a position where the light beam is condensed is defined as a pixel reduced image plane, and an intermediate image on this plane is defined as a pixel reduced image.
It can be understood from the above description that the reduced pixel image is smaller than the pixel of the reflective light valve element. This state is defined as pixel reduction.

Hereinafter, the gist of the present invention will be described. FIG. 1 schematically shows a state in which light crosstalks with a pixel display region 2 that is an adjacent region of the pixel display region 1. Light rays are traveling from top to bottom. Symbol L indicates the light intensity distribution at this time.
FIG. 2 schematically shows a state in which a V-shaped groove G is formed in the vicinity of the boundary between the pixel display region 1 (hereinafter simply referred to as “region 1”) and the pixel display region 2 (hereinafter simply referred to as “region 2”). Show. In order to make the explanation easy to understand, it is slightly enlarged than FIG. Reference numeral Sa denotes a light incident surface of the screen S. The refractive index N1 on the upper side of the screen S in FIG. 2 is smaller than the refractive index N2 of the region 1 and the region 2. The refractive index of the groove is also N1.

In FIG. 2, the light beam 2 that has conventionally entered the region 2 is partially reflected by the surface 2 as the inclined surface of the groove G as indicated by the solid line. The components that are not reflected are transmitted through the surface 2 and enter the region 2. However, if the incident angle with respect to the surface 2 is increased, the reflectance can be increased.
When the incident angle θ1 of the light beam 2 with respect to the surface 2 and the light beam incident angle θ2 to the surface 1 as the inclined surface of the light beam 2 reflected by the surface 2 are compared, θ1> θ2. Therefore, the light beam 2 incident on the surface 1 hardly enters the surface 1 and enters the region 1.
Further, the incident angle θ3 of the light beam 1 incident on the surface 1 without being incident on the surface 2 is smaller than θ1, and therefore enters the region 1 without being substantially reflected by the surface 1.
FIG. 3 is a schematic diagram in which the light ray components that have cross-talked to the region 1 without entering the region 2 are also shown based on FIG. The light beam that has not entered the region 2 until now receives the same action as described in FIG. 2 and enters the region 2 without crosstalking with the region 1. Rays 3 and 4 are rays that should enter region 2.
As described above, the surface 1 and the surface 2 of the groove G can have a reflection / transmission separation function with respect to the incident angle of the light beam.

As described above, the light beam condensed on the pixel reduced image plane again becomes divergent light and is guided to the enlargement projection optical system. At this time, the reduced pixel image plane is arranged so as to be the object plane of the enlargement projection optical system 48, and the reduced pixel image on the object plane is placed on the screen S via the enlargement projection optical system 48. Projection display.
However, when the pixel reduction ratio is increased by this method, the contrast is lowered due to the depolarization effect of the microlens. Therefore, if priority is given to not sacrificing contrast, the pixel reduction rate becomes low, and the light beam spot size reaching the back surface of the screen S becomes larger than the pixel display size.
However, even in this state, the light beam protruding from the adjacent pixel display area on the back surface of the screen S can be guided to the desired pixel display area by the function of the screen S described above, so that when the screen is viewed from the surface of the screen S, Adjacent pixel images do not appear to partially overlap. Or the conventional malfunction that the information of the pixel image adjacent to this is mixed in arbitrary pixel display areas will also be eliminated.

The second embodiment will be described based on FIG. Note that the same parts as those in the above embodiment are denoted by the same reference numerals, and unless otherwise specified, description of the configuration and functions already described is omitted, and only the main part will be described (the same applies to other embodiments below).
A state after the light beam that has conventionally cross-talked to the region 2 by the surface 1 and the surface 2 of the groove G enters the region 1 will be described.
It is desirable that the light beam 2 (solid line) that has crosstalked with the region 2 stays in the region 1 after being guided to the region 1 by the groove surface 2. In order to realize this, a total reflection surface as a light reflection layer is provided at the boundary between the region 1 and the region 2. The total reflection surface is provided on the boundary surface in the screen thickness direction of any adjacent pixel display region (here, region 1 and region 2) in a region deeper than the depth of the groove G. By providing the total reflection surface, the light beam 2 is not transmitted to the left region of the region 1 but can be confined in the region 1. The light beam 1 indicated by the broken line can be confined in the region 1 as well.
Even if the total reflection surface is a light shielding member, the above-described crosstalk problem can be avoided, but the amount of light in the display pixel region is reduced because light rays are absorbed. It is better to use a reflective surface in order to suppress light loss due to absorption.

A third embodiment will be described with reference to FIG.
In the present embodiment, a diffusion surface as a light diffusion layer is provided in the pixel display region. The diffusing surface is provided parallel to the light incident surface Sa of the screen S at a position deeper than the groove G in an arbitrary pixel display region (here, region 1 and region 2). All the light rays entering the region 1 reach the diffusion surface and are diffused. As a result, the directivity of light rays that enter the region 1 at various incident angles is made uniform.
In the region above and below the diffusion surface, the light intensity is made uniform in the lower region. As described above, by improving the uniformity of the light intensity distribution in the pixel display area, for example, when both the area 1 and the area 2 display white, the light intensity decreases at the boundary of the area. Is eliminated and a smooth image is obtained.
Here, by forming the total reflection surface continuously below the diffusion surface, that is, by forming the total reflection surface so as to be continuous up and down in the thickness direction of the screen, the light diffused by the diffusion surface is adjacent to the pixel. There is no crosstalk in the display area.

A fourth embodiment will be described with reference to FIG.
In this embodiment, the surface (inclined surface) of the groove G has a positive curvature. The two rays 1 and 2 shown in the figure are rays that should be incident on the region 1 originally. Since the light beam traveling toward the screen S is condensed, when the vertical direction is taken as the Z axis in FIG. 7, the angle formed by the light beam 2 with the Z axis is larger than the angle formed by the light beam 1 with the Z axis. .
Here, regarding the incident angle with respect to the surface 2, in the case of FIG. 2, the incident angle of the light beam 1 is larger than the incident angle of the light beam 2, but in the case of FIG. 7, the difference can be reduced. Is possible.
Since the reflection / transmission separation characteristics on the surface 2 are dependent on the incident angle, the configuration shown in FIG. 7 reduces the incident angle difference between the light beam 1 and the light beam 2 and provides the effect of making the reflectance substantially equal. .

Further, when attention is paid to the surface 1, the angle difference at which the light beam 1 reflected by the surface 2 and the light beam 2 enter the surface 1 is smaller than in the case of FIG. This means that the transmittance difference on the surface 1 is reduced.
As described above, in the case of FIG. 7 as compared with the case of FIG. 2, an effect of reducing the incident angle dependency of the light beam taken into the predetermined pixel display region can be obtained.

The fifth embodiment will be described with reference to FIGS.
First, the configuration of the rear projection type rear projector will be described with reference to FIG. In the case of a rear projector, there are many cases in which light rays including image information are projected from an oblique direction with respect to the normal line of the screen surface (light incident surface Sa).
That is, the incident angle to the screen S is different within the screen surface. In FIG. 8, the upper side has a larger incident angle.
Assuming that FIG. 8 is an XZ plane, the incident angle of light on the screen S is not uniform also on the YZ plane, and the incident angle increases with increasing distance from the center of the screen S in the ± X direction.
As described above, when the light ray is incident obliquely on the screen surface, it is necessary to improve the configuration of the surface of the groove G.

When a light beam is incident at an angle as shown in FIG. 9, the surface 2 cannot reflect the light beam. On the other hand, as shown in FIG. 9, if the surface 2 is tilted, the surface 2 can reflect light rays.
That is, if the angle formed by the normal line of the screen surface and the light beam is φ1 and the angle formed by the normal line of the screen and the groove surface 2 is φ2, the surface 2 reflects the light beam if the relationship φ2> φ1 is satisfied. be able to.
Here, φ1 is not uniform within the screen surface. If the screen surface is an XY plane, φ1 (X, Y) can be expressed as a function of coordinates on the XY plane.
Accordingly, if φ2 (X, Y)> φ1 (X, Y) is satisfied at an arbitrary position on the screen surface, the light beam that has entered the region 2 at any position on the screen S is Can lead to 1.

When the screen surface is an XY plane, the angle formed by the light beam projected on the screen S and the screen surface is not uniform within the screen surface. Accordingly, since the inclination angle of the separation surface for obtaining the reflection / transmission separation characteristic of the light beam at an arbitrary incident position is strictly different in the screen surface, the inclination of the separation surface in all pixel display regions. Manufacturing with different angles increases the cost.
However, if the screen surface is divided into a plurality of finite regions, and the inclination angles of the separation surfaces are the same in the divided regions, the cost can be reduced.

Next, a sixth embodiment will be described. In the present embodiment, the groove G is sealed with a sealing material, and the refractive index N2 of the sealing material is larger than the refractive index N1 of the screen S. However, the refractive index here is independent of the refractive index in the first embodiment.
First, the point that the reflection action on the surface 2 changes depending on the refractive index N3 of the groove and the refractive index N1 of the screen S will be described. If nothing is filled in the groove, N3 <N1. On the other hand, when filled with a material (encapsulant) having a higher refractive index than the screen S, N2> N1. The relational expression between the light incident angle and the reflectance with respect to the surface 2 is different when N2 <N1 and when N2> N1.
This is, for example, as described in Optics (Kazumi Murata, published by Science Co., p29, FIG. 2.4).
In order to satisfy the object of the invention, it is advantageous that N2> N1. That is, when N2> N1, the reflectivity near the critical angle is close to 100%, and the reflectivity decreases sharply below the critical angle, so that the reflection / transmission separation characteristics are improved.

Next, a seventh embodiment will be described.
Consider two types of rays incident on surface 2. A light beam that should enter the region 1 is a light beam 1, and a light beam that should enter the region 2 is a light beam 2. The incident angles of the light beam 1 and the light beam 2 with respect to the surface 2 are denoted by ψ1 and ψ2, respectively.
At this time, if the surface 2 is set so as to reflect when ψ1 and transmit when ψ2, the light beam 1 can be reflected and guided to the region 1, and at the same time, the light beam 2 can be transmitted and guided to the region 2.

The eighth embodiment will be described with reference to FIG.
The light rays 1 and 2 used in the above description will be described in detail. First, considering the light group 1 to enter the region 1, the light group 1 is generally classified into a principal light and other light groups defined in optical terms.
The other ray groups are classified into marginal rays defined in general optical terms and other ray groups.
In the display device targeted by the present invention, the light source is often a lamp light source. In this case, as shown in FIG. 11, there is a light beam 1 incident on the surface 2 at an incident angle smaller than the marginal light beam.
In FIG. 11, the incident position on the surface 2 is the same for the light beam 1 and the marginal light beam, but the incident angles are different. Therefore, the marginal ray can also be reflected by causing the surface 2 to reflect the ray 1 having a smaller (smallest) incident angle than the marginal ray.

Here, the angle formed by the ray 1 with the normal line of the screen S is positive when the sign of the angle is defined as positive in the clockwise direction. On the other hand, although not shown in FIG. 10, the angle formed by the light ray incident on the surface 2 and incident on the region 2 with the normal line of the screen S is negative.
Further, the angle formed with the normal line of the screen S is larger than the angle formed by the principal ray with the normal line. Further, the light beam 2 to be incident on the region 2 has a smaller incident angle on the surface 2 than the light beam 1.
Therefore, in order to selectively reflect the light beam to be incident on the region 1 and selectively transmit the light beam to be incident on the region 2 on the surface 2, the light beam 1 is reflected and the light beam 2 is transmitted. This means that the inclination of the surface 2 may be set.

Based on FIG. 12, a ninth embodiment will be described.
Up to this point, the description has focused on light rays that should reach region 1 that is crosstalking with region 2. Next, a method of guiding the light beam to the region 2 when the light beam that should reach the region 2 is crosstalking to the region 1 will be described below.
In FIG. 12, two light rays incident on the surface 1 are drawn, and it is assumed that both of these light rays are originally to be guided to the region 2. These rays are reflected by surface 1, transmitted by surface 2, and guided to region 2. In order to reflect these light rays on the surface 1, it is necessary to make the inclined surface smaller in angle with the normal of the screen surface than the surface 2.

However, the problem here is that there may be light rays to be guided to the region 1 while exhibiting the same incident conditions as the light rays shown in FIG. In such a case, it is difficult to obtain a desired reflection / transmission separation function by the surface 1. However, the following problems can be solved by doing the following.
The feature shown in FIG. 13 is that the center of the intensity distribution of the light beam to be guided to the region 2 is shifted to the pixel display region 3 (hereinafter simply referred to as “region 3”) side from the center of the region 2. The light is not crosstalk. At this time, the light that crosstalks to the right region 3 can be avoided by the method described so far.
Further, since there is no crosstalk with the region 1, the surface (inclined surface) 11 of the region 1 and the surface (inclined surface) 21 of the region 2 do not require the reflection / transmission separation characteristics.
That is, since only the rays to be guided to the region 1 are incident on the surface 11, it is only necessary to transmit them. Similarly, only the rays to be guided to the region 2 are incident on the surface 21, so that these can be transmitted. What is necessary is tenth embodiment.

When the state of FIG. 13 is shown on the screen surface, that is, the XY plane, as shown in FIG. 14, the arbitrary region 1 is indicated by a square, and the area of the luminous flux that generates the pixel image of the region 1 is indicated by a circle. And the center of the circle is off. It is a groove in the pixel display area indicated by the hatched area.
When the light incident condition on the screen is as shown in FIG. 8, the relationship of FIG. 14 with respect to the entire screen surface is as shown in FIG.

If the light beam forming the pixel image projected on the screen S is expressed as a spot, the position of the spot on the back surface of the screen S and the pixel image display area on the screen S are shifted as shown in FIG. That is, the center position of the spot of the luminous flux that generates the image of the pixel display area is shifted in the lower left direction in the area to the right of the center of the screen S, and is shifted in the lower right direction in the area to the left of the center of the screen S. ing.
The spot position can be controlled by the aberration correction design of the projection optical system. By determining the width of the groove portion in the XY plane of the pixel display area corresponding to the spot and the inclination of the reflection / transmission surface constituting the groove G with respect to the spot position obtained in this way, The shape of G is determined and the desired effect is obtained.
Since the width of the groove part and the inclination of the reflection / transmission surface constituting the groove G differ depending on the position on the screen S, the depth of the groove G in the screen thickness direction also differs depending on the position on the screen S (first). 11 embodiments).

As described in the description of FIG. 12, the effect of selectively reflecting / transmitting and separating light rays can be obtained on the surface 2 constituting the groove G, but it is difficult to obtain the effect on the surface 1, and the light enters the surface 1. In some cases, the light beam to be guided to the region 1 may be guided to the region 2.
However, if the cross-sectional shape of the groove G is formed so that the surface 1 is parallel to the normal of the screen S (perpendicular to the light incident surface Sa) as shown in FIG. Thus, there is no problem that only the light beam to be guided to the region 1 and the light beam to be guided to the region 1 are guided to the region 2 (a twelfth embodiment).

When the groove G as shown in FIG. 16 is actually produced, it is difficult to form a ridge line where the surface 1 and the surface 2 intersect. However, as shown in FIG. 17, if the bottom surface 3 as the connecting surface is present, the manufacture is easy. In this case, the position of the ridgeline where the bottom surface 3 and the inclined surface 2 intersect is made to be the boundary of the pixel display region (13th embodiment).
In FIG. 17, the bottom surface 3 is expressed by a plane, but there is no problem in actual use even if it is not a complete plane. Moreover, even if R (roundness) is attached to the portion where the inclined surface 2 and the bottom surface 3 intersect, there are few harmful effects in actual use.

A fourteenth embodiment will be described based on FIG. In addition to the embodiments described so far, for example, a configuration in which an inclined surface is divided into Fresnel shapes is conceivable. The inclined surface at this time may have the light reflection / transmission separation function already described.
In FIG. 18, the projection light is incident from the right side of the figure. The illustrated light beams 1 and 2 are cross-talked to the region 2 side on the light incident surface Sa of the screen S, but are reflected by the inclined surface of the groove G provided on the light incident surface Sa of the screen S. Has been led to.
On the other hand, the light rays 3 and 4 are light rays that should reach the region 2, and these are refracted and transmitted on the inclined surface and guided to the region 2.
In each of the above embodiments, an example using a reflective light valve element has been described, but the same function can be obtained even with a configuration using a transmissive light valve element.

It is a schematic diagram which shows the state where the light cross-talks to the adjacent area | region of a specific pixel display area. It is a schematic diagram which shows the guidance state of the light ray by the V-shaped groove | channel formed in the light-projection surface side of a rear projection screen. It is a schematic diagram which shows the guidance state of the light ray by the V-shaped groove | channel formed in the light-projection surface side of a rear projection screen. It is a schematic diagram of the whole structure in a 1st embodiment. It is a figure which shows the groove peripheral part of the rear projection screen in 2nd Embodiment. It is a figure which shows the groove peripheral part of the rear projection screen in 3rd Embodiment. It is a figure which shows the groove peripheral part of the rear projection screen in 4th Embodiment. It is a figure which shows the path | route of the irradiation light to a rear projection screen. It is a figure which shows the state which cannot reflect a light beam by the inclined surface of a groove | channel. It is a figure which shows the inclined surface shape of the groove | channel in 5th Embodiment. It is a figure which shows the groove peripheral part of the rear projection screen in 8th Embodiment. It is a figure which shows the reflective state of the light ray by the difference in the angle of the inclined surface of a groove | channel. It is a figure which shows the some groove peripheral part of the rear projection screen in 10th Embodiment. It is a figure which shows the state which the area | region of a light beam and the pixel display area corresponding to this have shifted | deviated. It is a figure which shows the state which the area | region of a light beam and the pixel display area corresponding to this have shifted | deviated on a rear projection screen. It is a figure which shows the groove peripheral part of the rear projection screen in 12th Embodiment. It is a figure which shows the groove peripheral part of the rear projection screen in 13th Embodiment. It is a figure which shows the groove peripheral part of the rear projection screen in 14th Embodiment. It is a figure which shows the relationship between the enlarged and projected pixel image, and the enlarged and projected pixel image shifted by 1/2 pitch pixel. It is a figure which shows the synthesized image of the enlarged and projected pixel image. It is a figure which shows the relationship between the pixel reduction image projected and enlarged, and the pixel reduction image enlarged and projected by shifting 1/2 pitch pixel. It is a figure which shows the synthesized image of the pixel reduction image by which the expansion projection was carried out.

Explanation of symbols

DESCRIPTION OF SYMBOLS 15 Reflection type light valve element as a spatial light modulation element 31 Lamp light source as illumination light source 42 Element as pixel reduction means 46, 47 Pixel shift element as pixel shift means 48 Enlarging projection optical system G Groove S Rear projection screen

Claims (17)

At least an illumination light source, a spatial light modulation element having a plurality of pixels, an enlarged projection optical system, and a rear projection screen, and an image of a pixel of the spatial light modulation element is formed by the enlarged projection optical system by the rear projection screen. In an image display device that displays an enlarged projection on the projection surface of
A rear projection type image display apparatus comprising a groove having an inclined surface in the vicinity of an area boundary of an arbitrary pixel display area on the rear surface of the rear projection screen. At least an illumination light source, a spatial light modulation element having a plurality of pixels, a pixel reduction means for generating a reduced image of the pixels, a pixel shifting means for shifting the projection position of the reduced image, an enlarged projection optical system, and a rear surface A projection screen, and the reduced pixel image is enlarged and projected onto a projection surface of the rear projection screen by the enlargement projection optical system, and a position of a pixel image displayed on the image plane by the pixel shifting means is determined. In an image display device displayed in a shifted manner,
A rear projection type image display apparatus comprising a groove having an inclined surface in the vicinity of an area boundary of an arbitrary pixel display area on the rear surface of the rear projection screen. In the rear projection type image display device according to claim 1 or 2,
In an arbitrary pixel display area 1 and a pixel display area 2 adjacent to the pixel display area 1 on the rear projection screen, the inclined surface of the groove is at least one of the pixel display area 1 and the pixel display area 2. The inclined surface selectively reflects a light ray component that generates an image of the pixel display region without the inclined surface, and a light ray component that generates an image of the pixel display region with the inclined surface. A rear projection type image display device which selectively transmits light. In the rear projection type image display device according to claim 3,
A rear projection type image display apparatus, wherein a boundary surface in a screen thickness direction of an arbitrary adjacent pixel display region in a region deeper than the depth of the groove is a light reflection layer. The rear projection type image display device according to claim 4,
A rear projection type image display device, wherein a light diffusion layer is provided in a position deeper than the groove in an arbitrary pixel display region in parallel with a light incident surface of the rear projection screen. In the rear projection type image display device according to claim 5,
The rear projection type image display device, wherein the light reflection layer is continuous above and below the light diffusion layer in the screen thickness direction. In the rear projection type image display device according to claim 1 or 2,
The rear projection type image display device, wherein the inclined surface of the groove has a positive curvature. In the rear projection type image display device according to claim 1 or 2,
The inclination angle φ2 (X, Y) of the groove at an arbitrary coordinate (X, Y) on the light incident surface of the rear projection screen is greater than the light incident angle φ1 (X, Y) with respect to the screen normal at the same position. A rear projection type image display device characterized by being large. In the rear projection type image display device according to claim 1 or 2,
The groove is sealed with a sealing material, and the refractive index N2 of the sealing material is larger than the refractive index N1 of the rear projection screen. In the rear projection type image display device according to claim 1 or 2,
The incident angle of the light beam 1 to enter the arbitrary pixel display area 1 is ψ1 and the incident light beam 2 of the arbitrary pixel display area 2 adjacent to the pixel display area 1 is incident on the same inclined surface. A rear projection type image display device, wherein when the angle is ψ2, the inclined surface has an inclination angle that reflects the light beam 1 and transmits the light beam 2. The rear projection type image display device according to claim 10,
The rear projection type image display device, wherein the light beam 1 is a light beam having a minimum incident angle at an arbitrary incident position on the inclined surface. In the rear projection type image display device according to claim 1 or 2,
In the adjacent pixel display region, the groove is formed in a region including a part of the pixel display region, the groove has two inclined surfaces, and the first inclined surface is in the first pixel display region. And the second inclined surface is in the second pixel display region, and the inclined angle of each inclined surface is different. The rear projection type image display device according to claim 12,
A rear projection type image display apparatus characterized in that the center of an arbitrary pixel display area is shifted from the center position of a spot of a light beam that generates an image in the pixel display area. The rear projection type image display device according to claim 13,
With respect to the center of an arbitrary pixel display area, the center position of a light beam spot that generates an image of the pixel display area is shifted in the lower left direction in the right area from the center of the rear projection screen, and the rear projection A rear projection type image display device characterized in that the region left of the center of the screen is shifted to the lower right. In the rear projection type image display device according to claim 1 or 2,
The groove has two surfaces, one of the two surfaces is an inclined surface, and the other surface is a surface perpendicular to the light incident surface of the rear projection screen. Rear projection image display device. The rear projection type image display device according to claim 15,
The rear projection type image display device, wherein the groove has a connecting surface that connects the inclined surface and the vertical surface. In the rear projection screen used for the rear projection type image display device,
A rear projection screen comprising a groove having an inclined surface in the vicinity of a region boundary of an arbitrary pixel display region on the rear surface.

Images