JP2009198837A - Single plate type color display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a single plate type color display, capable of displaying a color image of high quality, without generating color breakup as in a field sequential system, while dimensionally reducing display configuration and lowering a manufacturing cost. <P>SOLUTION: This single plate type color display modulates lights in response to images for a red color, a green color and a blue color, by one sheet of a space light modulating element 1, and composes the modulated lights to conduct color display. In the color display, illumination lights R, G, B are incident, at incident angles different from each other, into respective areas where the light modulation is carried out in response to the images for the respective colors in the space light modulating element 1, and the respective modulated lights through the space light modulating element 1 are made incident into a projection optical system 2, while at least two optical paths for the modulated lights are bent in the vicinity of the first convergence point A, in the projection optical system 2, and the respective modulated lights are composed overlappedly in an image focusing face 103, to provide the color image. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a single-plate color display device that performs color display using a single spatial light modulator.

  As a conventional single-plate color display device, the display surface of one spatial light modulator is divided into three regions, and images of R, G, and B colors are simultaneously displayed in these regions. A color display device that is illuminated with illumination light of a color corresponding to the above is described. Some modulated light that has passed through each region of the spatial light modulator is synthesized by color synthesis means to display a color image.

  Although this color display device is a single plate type and displays images of each color at the same time, there is no color breaking phenomenon, and a liquid crystal display panel can be used as a spatial light modulation element (for example, (See Patent Document 1).

JP-A-9-265106

  By the way, in the single-plate type color display device described in the above-mentioned Patent Document 1, the configuration of the color synthesizing means is complicated, and it is difficult to reduce the size of the device and reduce the manufacturing cost. In addition, despite the single plate, the back focus of the projection optical system must be increased, and the projection optical system cannot be reduced in size.

  Further, in this color display device, the illumination light of each color illuminates the spatial light modulation element in the state of parallel light, so that the illumination light of one color also enters an adjacent region of another color, resulting in color mixing May occur. In order to prevent color mixing, it is conceivable to provide a non-display area between the areas. However, if a sufficient non-display area is secured, the spatial light modulation element will be enlarged and the advantage of the single plate type of miniaturization will be impaired. End up.

  Therefore, the present invention has been proposed in view of the above-described circumstances, and a single-plate type capable of displaying a high-quality color image while being able to reduce the size of the apparatus and reduce the manufacturing cost. An object is to provide a color display device.

  In order to solve the above-described problems and achieve the above object, a single-plate color display device according to the present invention has any one of the following configurations.

[Configuration 1]
Perform light modulation according to red, green and blue images by different areas in one spatial light modulation element, image the modulated light that has been modulated by each, and synthesize on the imaging surface, A single-plate color display device for displaying a color image, in which a red illumination unit that causes red light to enter a region in which light modulation is performed according to a red image in the spatial light modulation element, and green light in the spatial light modulation element Green illumination means for making green light incident on an area that performs light modulation according to an image, blue illumination means for making blue light incident on an area that performs light modulation according to an image for blue in a spatial light modulator, and spatial light A projection optical system that forms an image on the imaging surface of the modulated light of each color that has passed through the modulation element, and the incident angle of red light from the red illumination means to the region that performs light modulation according to the image for red, Light change according to green image The incident angle of the green light from the green illumination means to the area where the light is emitted and the incident angle of the blue light from the blue illumination means to the area where the light modulation is performed according to the blue image are different from each other, and the projection The optical system includes an optical path bending element that bends at least two optical paths of the modulated light of each color incident on the projection optical system in the vicinity of the primary condensing point in the projection optical system. By folding at least two optical paths of the modulated light of each color by the bending element, the color modulated light is superimposed on the image plane to be combined into a color image.

[Configuration 2]
A single-plate color display device having Configuration 1, characterized in that it has a projection lens for projecting an image on a screen with a color image synthesized by superimposing each color-modulated light on the imaging plane as an object point It is.

[Configuration 3]
In the single-plate color display device having Configuration 1 or Configuration 2, each color illumination unit emits laser light as illumination light, and a diffuser is installed in the vicinity of the spatial light modulator. .

  In this single-plate color display device, by using light with high parallelism as illumination light, the size of the first condensing point can be reduced, and the optical path bending means can be made smaller and less expensive. it can. In particular, a bright image can be efficiently displayed by using laser light as illumination light.

[Configuration 4]
The single-plate color display device having any one of Configurations 1 to 3 includes a drive circuit that drives the spatial light modulation element according to an image for each color, and the drive circuits are for red, green, and blue In addition to performing up / down / left / right inversion processing of an image, correction processing is performed on the size and shape of the image.

  In the single-plate color display device according to the present invention having the configuration 1, the projection optical system includes at least two optical paths of the modulated light beams of the respective colors incident on the projection optical system in the primary collection in the projection optical system. It has an optical path bending element that bends in the vicinity of the light spot, and by folding at least two optical paths of the modulated light of each color by this optical path bending element, the color modulated light is superimposed on the image plane and synthesized. Since the image is used, the projection optical system can be downsized and the manufacturing cost can be reduced.

  Since the single-plate color display device according to the present invention having the configuration 2 has a projection lens that projects an image on a screen by using a color image obtained by superimposing and synthesizing each color-modulated light on the imaging plane as an object point. The enlargement ratio of the image can be increased without increasing the size of the projection optical system.

  In the single-plate color display device according to the present invention having the configuration 3, each color illumination unit emits laser light as illumination light, and a diffuser is installed in the vicinity of the spatial light modulation element. Can be reduced in size, and the use efficiency of illumination light is high, so that a bright and good color reproducibility color display can be performed.

  In the single-plate color display device according to the present invention having the configuration 4, the drive circuit that drives the spatial light modulation element according to the image for each color performs the up / down / left / right inversion processing of the red, green, and blue images. In addition, since correction processing is performed for the size and shape of the image, it is possible to satisfactorily combine the images of the respective colors.

  That is, the present invention is a single-plate color that can display a high-quality color image without causing color breakup as in the field sequential method, while enabling a reduction in the size of the apparatus and a reduction in manufacturing cost. A display device can be provided.

  Hereinafter, the configuration of a single-plate color display device according to the present invention will be described in detail with reference to the drawings.

[Principle of the present invention]
FIG. 1 is a side view showing the principle of a single-plate color display device according to the present invention, (a) is a side view showing the operation of a projection optical system in a normal optical system, and (b) is a space view. It is a side view which shows the effect | action of a projection optical system when parallel light injects into a light modulation element, (c) is a side view which shows the effect | action of the projection optical system in the single-plate type color display apparatus which concerns on this invention.

  The single-plate color display device according to the present invention performs light modulation according to red, green, and blue images by different regions of a single spatial light modulator, and projects these modulated lights to form an image. A color image is displayed by superimposing them on the surface.

  With reference to FIG. 1, the principle of image synthesis of each color light in the present invention will be described. First, as shown in FIG. 1A, when an image displayed by the self-luminous spatial light modulation element 101 is projected onto the screen by the projection optical system 102, each pixel on the spatial light modulation element 101 is displayed. Of the light from the (light emitting point), the light that reaches the projection optical system 102 is condensed at one point on the screen 103 to form a real image. In this case, the condensing point of the light beam from the spatial light modulator 101 is only the image plane on the screen 103.

  Next, as shown in FIG. 1B, substantially parallel red (hereinafter referred to as R), green (hereinafter referred to as G) and blue (hereinafter referred to as B) illumination light is used for red (not shown). Consider a state in which the illumination unit, the green illumination unit, and the blue illumination unit are incident on the transmissive spatial light modulation element 101 at different incident angles, and the modulated light is projected onto the screen 103 by the projection optical system 102. The transmissive spatial light modulation element 101 is, for example, a laminate in which a polarizing plate and a liquid crystal display element are stacked and integrated. In this case, since the modulated light that has passed through each pixel on the spatial light modulator 101 is substantially parallel light, after once condensed at the focal position (first condensing point A) of the projection optical system 102, An inverted image is formed on the screen 103. Since the illumination light of each color of R, G, and B has different incident angles with respect to the spatial light modulation element 101, the first condensing point A of each modulated light is a different point.

  When the illumination light of each color of R, G, and B is incident on the spatial light modulation element 101 at the same incident angle (for example, vertical incidence), all the modulated light of each color is the same point (the focus of the projection optical system 102). After the light is condensed at the position, an inverted image is formed on the screen 103. At this time, the images of the respective colors are displayed side by side on the screen 103 in the same manner as in the state displayed on the spatial light modulator 101. In this case, color composition cannot be performed in a single-plate color display device according to the present invention, which will be described later.

  Then, as shown in FIG. 1 (c), mirrors 104 and 104 serving as optical path bending means are placed at two first condensing points A among the modulated lights of R, G and B colors, for example, By folding the optical paths of the modulated light of two colors R, B, and B, and superimposing them on the imaging position of the G modulated light, the images of the respective colors are synthesized. At this time, if the optical path is bent using one mirror 104 for one modulated light, the displayed image becomes a mirror image. That is, the R and B images are mirror images of the G image. Therefore, for example, by converting only the display image on the G spatial light modulation element 101 into a mirror image in advance, the image of each color is correctly superimposed on the screen 103, and a single-plate color display device that displays a color image is configured. Is done.

  Note that in the spatial light modulator 101 of this single-plate color display device, the display positions of the R, G, and B color images are not necessarily separated from each other. Since the incident angles of the R, G and B illumination lights with respect to the spatial light modulator 101 are different from each other, the first condensing point A of each modulated light is different. For example, the R illumination light is for G Even if it overlaps the image display area, color mixing does not occur. Therefore, in this single-plate color display device, the accuracy of the illumination means may be low, and the manufacture can be facilitated.

  By the way, there are so-called front projection and rear projection in a projection type image display device (projector). Generally, there are a case where it is installed on a desk or the like and a case where it is hung from the ceiling. Such an image display device incorporates an image processing circuit that inverts the display image vertically and horizontally so that it can cope with each use situation with one model. In a conventional three-plate type or single-plate type color display device, an inverted image can be obtained by changing the order of pixels vertically and horizontally for an image signal input to a spatial light modulator. However, in the single-plate color display device according to the present invention, when the image is inverted by the same method, there is a problem that the R image and the B image are switched at the time of the inversion. Furthermore, the convergence is completely out of order in an image with aberration correction or the like added. Therefore, in the present invention, inversion processing is performed before correcting each color image.

Embodiment of the present invention
FIG. 2 is a side view showing the configuration of the single-plate color display device in the first embodiment of the present invention.

  As shown in FIG. 2, the single-plate color display device according to the present invention has a different incident angle in each area where light modulation is performed in accordance with an image for each color in the spatial light modulation element 1. Illumination means for each color (not shown) that causes illumination light of corresponding colors (R, G, B) to enter. The single-plate color display device includes a projection optical system 2 that projects the modulated light of each color that has passed through the spatial light modulator 1.

  The projection optical system 2 includes a dove prism (trapezoidal prism) 4 serving as an optical path bending unit that bends at least two optical paths of each modulated light incident on the projection optical system 2 in the vicinity of the primary condensing point A. 4. The dove prisms 4 and 4 bend the optical paths of the R and B modulated light, and superimpose and synthesize each modulated light on the screen 103 which is the image forming surface to obtain a color image.

  In this single-plate color display device, by using the Dove prisms 4 and 4 or the right triangle prism as the optical path bending means, the device configuration can be made smaller than using the mirror. When the position of the screen 103 is changed, the imaging position can be adjusted by rotating the Dove prisms 4 and 4 in the plane.

  That is, in this single-plate color display device, the R, G, and B illumination lights having different incident angles as the substantially parallel lights are applied to the respective regions where the light modulation is performed according to the image for each color in the spatial light modulator 1. The modulated light that has passed through the spatial light modulation element 1 is bent by the Dove prisms 4 and 4 in the vicinity of the first condensing point A in the projection optical system 2, and three color images are synthesized on the image plane on the screen 103. To make a color image.

  FIG. 3 is a side view showing a configuration of a single-plate color display device according to the second embodiment of the present invention.

  In the single-plate color display device according to the present invention, as shown in FIG. 3, as the optical path bending means, two shift lenses (lenses with the optical axis offset) 5, 5 and one normal lens ( A lens 6 passing through the optical axis) can be used.

  In this case, since there is no inversion of the image displayed by the R and B modulated light whose optical path is bent, a correct color image can be displayed as it is without inversion processing. The powers of the shift lenses 5 and 5 and the normal lens 6 are adjusted so that the sizes (magnifications) of the three color images are equal.

  FIG. 4 is a side view showing the configuration of a single-plate color display device according to the third embodiment of the present invention.

  In the single-plate color display device according to the present invention, as shown in FIG. 4, two-reflection bending elements 7 and 7 made up of two right triangular prisms can be used as the optical path bending means.

  Even when the folding elements 7 and 7 are used, the image displayed by the R and B modulated light is not inverted, and a correct color image can be displayed as it is without performing the inversion process. When the position of the screen 103 changes, it can be adjusted by rotating one of the two right-angled triangular prisms constituting the bending elements 7 and 7 in the plane.

  In each of the above-described embodiments, the imaging surface is on the screen 103 and the color composition surface is also on the screen 103. Therefore, if the projection distance to the screen 103 is constant, readjustment of color misregistration or the like is unnecessary, which is suitable for a configuration such as a fixed front projector or rear projector.

  FIG. 5 is a side view showing the configuration of a single-plate color display device according to the fourth embodiment of the present invention.

  In the single-plate color display device according to the present invention, as shown in FIG. 5, the projection optical system 2 synthesizes each modulated light on the imaging plane B to form a real image, and this real image is a projection lens. 8 may be configured to be projected onto the screen 103.

  In the projection optical system 2, even if the projection distance to the screen 103 changes, it is possible to display a color image without color misregistration only by performing focus adjustment with the projection lens 8. This single-plate color display device is suitable for being configured as a portable (portable) front projector.

  FIG. 6 is a perspective view showing a configuration in which a reflective liquid crystal display panel is used as a spatial light modulation element in a single-plate color display device according to the present invention.

  The single-plate color display device according to the present invention can be configured using a reflective liquid crystal display panel 11 as a spatial light modulation element, as shown in FIG. In this single-plate color display device, illumination light emitted from light sources 9 for R, G, and B colors serving as illumination means for each color is incident on a polarization beam splitter (PBS) 10. The light is reflected by the polarization reflection surface and enters the reflective liquid crystal display panel 11 at different incident angles. The illumination light of each color is modulated and reflected by the reflective liquid crystal display panel 11 according to the display image. The modulated light reflected by the reflective liquid crystal display panel 11 enters the polarization beam splitter 10, passes through the polarization reflection surface of the polarization beam splitter 10, and enters the projection optical system 2.

  The projection optical system 2 has the same configuration as that in each of the above-described embodiments, and displays the color image on the screen 103 by synthesizing the modulated light of each color.

  In this single-plate color display device, the difference in the incident angle of the illumination light of each color to the spatial light modulation element may be 3 ° to 5 °. Therefore, as the spatial light modulation element, an element that modulates illumination light by swinging a fine mirror angle corresponding to a pixel, such as a micromirror device (DMD), can be used.

  FIG. 7 is a perspective view showing a configuration using a laser light source as the light source of the illumination means in the single-plate color display device according to the present invention.

  As shown in FIG. 7, the single-plate color display device according to the present invention can be configured by using R, G, and B color laser light sources 12 that emit laser light as illumination light as illumination means for each color. . When the laser light source 12 is used, it is desirable to install a diffuser 13 on the optical path from the laser light source 12 to the spatial light modulator 1. In this single-plate color display device, the spatial light modulation element and the projection optical system 2 or the optical system including the spatial light modulation element, the projection optical system 2 and the polarization beam splitter 10 is configured in the same manner as in the above-described embodiments. Has been.

  In this single-plate color display device, the laser beam with high parallelism is used as the illumination light, so that the size of the first condensing point can be reduced, so that the optical path bending means is downsized and inexpensive. Can be. Further, by using laser light as illumination light, a bright color image can be displayed efficiently.

  Laser light has high power and the parallelism of light rays is very good, but it tends to cause interference fringes due to interface reflections and roughness due to scintillation. Such interference fringes and scintillation can be prevented by the diffuser 13.

  As the diffuser 13, a hologram diffuser is used and is installed in the vicinity of the illumination light incident side of the spatial light modulator, and when a reflective spatial light modulator is used, as shown in FIG. It was effective to install the beam splitter 10 near the illumination light incident side. If the diffusion angle in the diffuser 13 is too small, the effect is small, and if it is too large, the size of the first condensing point becomes large, resulting in inconvenience in separation of each color. Therefore, about 0.5 ° to 5 ° is preferable. I understood. When unevenness of each diffusion in the hologram diffuser is observed, it is preferable to use a plurality of diffusers or to reciprocate the diffuser in a direction substantially orthogonal to the incident direction of the illumination light.

  FIG. 8 is a block diagram showing the configuration of the drive circuit in the single-plate color display device according to the present invention.

  As shown in FIG. 8, the single-plate color display device according to the present invention includes a drive circuit 14 that drives the spatial light modulator 1 according to an image for each color. The drive circuit 14 can perform up / down / left / right reversal processing of red, green, and blue images, and can also perform correction processing on the size and shape of the image.

  The drive circuit 14 is a circuit that processes RGB image signals input from a frame memory (not shown) and passes the processed signals to the driver circuit 19 to drive the spatial light modulator 1. The image signal output from the driver circuit 19 is an image signal displayed by one spatial light modulator 1. Therefore, the spatial light modulator 1 can be a spatial light modulator used in a conventional three-plate color display device. In the spatial light modulator 1, the image display area is divided into three areas, and light modulation corresponding to the image of each color is performed in each area.

  In this drive circuit 14, first, an up / down inversion process of an image is performed by the up / down / left / right inversion circuit 15. In the first and fourth embodiments described above, it is necessary to invert the image signal of only G in the drive circuit 14. In addition, when performing upside down or left / right reversal of the image in accordance with the usage state of the display device, reversal processing is performed on each color image.

  Next, the magnification and distortion correction circuit 16 performs image magnification and distortion correction processing. Each of the R, G, and B image signals is converted in pixel density as necessary, and is approximately 略 the size of the display area in the spatial light modulator 1. Actually, in order to provide a margin for convergence processing, which will be described later, the size may be further reduced by several% to several tens of%.

  The image size of each color may be slightly different from each other. This is because chromatic aberration correction is performed in the projection optical system 2. This correction processing is effective for using an inexpensive optical system. In general, the projection optical system 2 is configured by combining a large number of lenses in order to correct various aberrations. In this single-plate color display device, the image size of each color can be corrected by image processing, so that the number of constituent lenses in the projection optical system 2 can be minimized.

  For example, when chromatic aberration of magnification occurs, there is a difference in the position of the focus surface and the size of the image depending on the color. Therefore, the entire color cannot be matched only by shifting the position of the image. In the conventional three-plate type color display device, the convergence adjustment is performed by shifting the position of each spatial light modulation element. However, there is no chromatic aberration in the projection optical system. Even in a field sequential single-plate color display device, the influence of chromatic aberration of the projection optical system is inevitable.

  In the single-plate color display device according to the present invention, the convergence adjustment can be performed by independently adjusting the size of the image of each color by processing the image signal. It is not necessary to adjust the accuracy.

  Further, distortion and distortion are corrected by the magnification and distortion correction circuit 16. In this single-plate color display device, an image magnification shift or distortion is likely to occur on the image plane due to differences in the optical path lengths of R, G, B in the optical path bending means. These image magnification shifts and distortions can be prevented. By performing these corrections by the magnification and distortion correction circuit 16, it is possible to ease the requirement for an increase in the number of parts and parts manufacturing accuracy and to avoid an increase in manufacturing cost, compared with adjustment by adding optical components for adjustment. it can.

  When laser light is used as the illumination light, the parallelism of the illumination light is high, so that the depth of focus is large, and since it is a single wavelength, there is no spread due to chromatic dispersion, so the magnification and distortion correction circuit 16 The effect of image processing by is particularly high.

  Then, the convergence of each color image is adjusted by the digital convergence circuit 18 that adjusts the positional relationship between the images of the respective colors. This process can also be used as color misregistration correction when the position of the screen 103 changes, and can also be used as an aid for mechanical correction by the optical path bending means.

  A correction amount in the magnification and distortion correction circuit 16 and the digital convergence circuit 18 is input via a correction amount input unit 17. Then, the spatial light modulator 1 is driven via the driver circuit 19.

It is a side view which shows the principle of the single-plate type color display apparatus which concerns on this invention, (a) is a side view which shows the effect | action of the projection optical system in a normal optical system, (b) is a spatial light modulation element. It is a side view which shows the effect | action of a projection optical system when parallel light injects, (c) is a side view which shows the effect | action of the projection optical system in the single-plate type color display apparatus which concerns on this invention. It is a side view which shows the structure of the single-plate type color display apparatus in the 1st implementation of this invention. It is a side view which shows the structure of the single-plate type color display apparatus in the 2nd implementation of this invention. It is a side view which shows the structure of the single-plate type color display apparatus in the 3rd implementation of this invention. It is a side view which shows the structure of the single-plate type color display apparatus in the 4th implementation of this invention. 1 is a perspective view showing a configuration in which a reflective liquid crystal display panel is used as a spatial light modulation element in a single-plate color display device according to the present invention. In the single-plate color display device according to the present invention, it is a perspective view showing a configuration using a laser light source as a light source of illumination means. It is a block diagram which shows the structure of the drive circuit in the said single plate type color display apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spatial light modulation element 2 Projection optical system 4 Dove prism (trapezoid prism)
5 Shift lens 6 Normal lens 7 Bending element 8 Projection lens 9 Light source 10 Polarizing beam splitter 11 Reflective liquid crystal display panel 12 Laser light source 13 Diffuser 14 Drive circuit 103 Screen

Claims (4)

Perform light modulation according to red, green and blue images by different areas in one spatial light modulation element, image the modulated light that has been modulated by each, and synthesize on the imaging surface, A single-plate color display device for displaying a color image,
A red illumination means for causing red light to enter a region in which light modulation is performed according to a red image in the spatial light modulation element;
Green illumination means for causing green light to enter a region where light modulation according to a green image is performed in the spatial light modulation element;
Blue illumination means for causing blue light to enter a region where light modulation is performed according to a blue image in the spatial light modulator;
A projection optical system that forms an image of the modulated light of each color that has passed through the spatial light modulation element on an imaging surface;
The incident angle of the red light from the red illumination means to the area that performs light modulation according to the red image, and the green light from the green illumination means to the area that performs light modulation according to the green image The incident angle is different from the incident angle of the blue light from the blue illuminating means to the region that performs light modulation according to the blue image,
The projection optical system has an optical path bending element that bends at least two optical paths of modulated light of each color incident on the projection optical system in the vicinity of a primary condensing point in the projection optical system, A single-plate color display device characterized in that at least two optical paths of the modulated light of each color are bent by the optical path bending element, and the color modulated light is superimposed on the image plane to be combined into a color image. . 2. A single-plate color display device according to claim 1, further comprising: a projection lens that projects an image on a screen by using a color image synthesized by superimposing the color-modulated light beams on the imaging plane as an object point. . Each color illumination means emits laser light as the illumination light,
The single plate type color display device according to claim 1, wherein a diffuser is installed in the vicinity of the spatial light modulation element. A drive circuit for driving the spatial light modulator in accordance with the image for each color;
4. The drive circuit according to claim 1, wherein the drive circuit performs up / down / left / right inversion processing of the red, green, and blue images and corrects the size and shape of the image. The single plate type color display device according to any one of the above.

Images