JPH0876055A - Image projection device - Google Patents

Abstract

(57) [Summary] [Purpose] By dividing the reflector of the projection optical system,
The shape of the projection device is thinned to reduce uneven brightness of the projected image on the screen surface. [Structure] The two-divided plane reflecting mirrors 4 and 11 reflect light rays coming from a pixel between pixels A-C and B-C of a liquid crystal original image toward the next two-divided plane reflecting mirrors 5 and 15. To do. The light ray 9 from the liquid crystal original image reflected by the plane reflecting mirror 5 is focused on the screen 10 as a light ray from the virtual image 6 of the original image and the virtual image 7 of the converging optical system. Similarly, the plane reflecting mirror 1
A light ray 14 from the liquid crystal original image reflected by 5 is imaged on the screen 10 as a light ray from the virtual image 12 of the original image and the virtual image 13 of the converging optical system. As described above, by using the split plane mirrors 5 and 15, the depth of the device can be made thin, and the incident angles of the light rays 8 and 14 can be made more vertical, so that the brightness of the reproduced image on the screen can be made uniform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image projection device,
More specifically, the present invention relates to a thin image projection device that projects a video image or a computer image.

[0002]

2. Description of the Related Art In recent years, as an image reproducing apparatus for reproducing an image having a large screen of about 40 inches or more, a projection type has been regarded as promising in terms of price, size, productivity and maintenance. Above all, the method of forming the original image by controlling the transmitted light path with the liquid crystal is suitable for exhibiting the above characteristics as compared with the method using the cathode ray tube (CRT). In the conventional image projection device, when projecting and forming the original image on the screen, the size of the device, especially the depth, is designed to be thin while using the lens and the plane reflecting mirror as a holder to gain the optical path length necessary for expansion. ing.

FIG. 5 is a block diagram of a conventional rear projection device using liquid crystal, in which 31 is a liquid crystal panel, 32 is a converging lens system, 33 is a light source and a condenser mirror, and 34 and 35 are plane reflecting mirrors. , 36.37 is a virtual image, 38.39 is an optical path, and 40 is a screen. An original image is formed on the liquid crystal panel 31. A and B are the edge portions of the liquid crystal panel 31, and C is a pixel on the optical axis portion of the optical system. Converging lens system 32
Represents a converging lens system of an optical system. The light source is a halogen lamp.

The light emitted from the light source 33 travels substantially parallel to the optical axis and enters the liquid crystal panel 31. Pixels A, B and C
The light transmitted from the above is imaged on A ', B', C'on the screen 40 by the following projection optical system. Here, the projection optical system, for example, in order to reduce the depth of the entire device,
It is composed of plane reflecting mirrors 34 and 35. Where the virtual image 3
6 and 37 are the liquid crystal panel 3 viewed from the screen 40.
1 is a virtual image of 1 and the convergent lens system 32. Light rays emitted from the pixel A and the pixel B pass through the optical paths 38 and 39 and the screen 40.
Image on.

[0005]

In recent years, televisions and image display devices are required to have larger and wider angles of view and high-quality reproduced images. In an image projection apparatus having a large screen, the reflecting mirror used in the projection optical system also becomes large, and in particular, a plane reflecting mirror (3 in FIG. 5) that reflects toward the screen.
In 5), since the area is quite large and is not parallel to the screen, the depth of the image projection apparatus cannot be reduced. Further, there is a problem that the brightness on the screen is very uneven because the angles and the amounts of light rays incident on the central portion C'and the edge portions A'and B'of the screen are greatly different.

The present invention has been made in view of such circumstances, and by dividing the reflecting mirror of the projection optical system,
An object of the present invention is to provide an image projection device in which the shape of the projection device is thinned to reduce the unevenness of the brightness of the projected image on the screen.

[0007]

In order to solve the above problems, the present invention provides (1) an image projection apparatus for projecting an original image on a screen, a liquid crystal panel on which an original image is formed, and a liquid crystal panel of the liquid crystal panel. In order to reflect the light rays coming from the pixels, it is composed of a plane reflecting mirror group that divides the plane reflection of the image forming optical system into a plurality, and a screen that forms an image of the light rays from the plane reflecting mirror group. (2) It has an optical system that divides corresponding to the boundary of the plane reflecting mirror group to form a divided image group forming an original image on a screen, and (3) the divided original image group. Among them, an optical element group for matching the optical path length from some of the divided original images with the optical path length from the remaining divided original images, and further, (4)
The divided original image group is formed on a screen, and an adjustment mechanism system is provided for moving the plane reflecting mirror group in parallel and rotating in order to synthesize the divided projected image group. Further, (5) the divided original image When the joining portions between the images overlap each other, the same pixel should have a filtered value, and (6) in the projection optical path, an optical path shield plate should be provided so that the light rays between the divided original images do not interfere with each other. It is characterized by having.

[0008]

According to the image projection apparatus of the present invention having the above-described structure, the original image is projected on the screen, and the plane reflection of the image forming optical system is divided into a plurality of plane reflecting mirror groups and reflected. It has an optical system that forms an image on the screen of divided original images that form the divided original image corresponding to the boundary of the reflecting mirror group, and also a divided projection image in which the divided original image group is formed on the screen. In order to combine the groups, it has an adjusting mechanism system that translates and rotates the plane reflecting mirror group,
When the joints between divided original images overlap each other, the same pixel is filtered, and
Since the projection optical path has an optical path blocking plate so that the light beams between the divided original images do not interfere with each other, a thin and practical display device with uniform screen brightness can be obtained despite a large angle of view. .

[0009]

Embodiments will be described below with reference to the drawings. FIG. 1 is a configuration diagram for explaining an embodiment of an image projection apparatus according to the present invention. In the figure, 1 is a liquid crystal panel, 2 is a converging lens system, 3 is a light source and a condenser mirror, and 4 and 5 are planes. Reflecting mirrors (divided reflecting mirrors), 6 and 7 are virtual images, 8 is light rays, 9 is an optical element group, 10 is a screen, 11 and 15 are flat reflecting mirrors (divided reflecting mirrors), 12 and 13 are virtual images, 14 and 16 Is a ray.

An original image is formed on the liquid crystal panel 1.
A and B are the edge portions of the liquid crystal panel 1, and C is a pixel on the optical axis portion of the optical system. The convergent lens system 21 represents a convergent lens system of an optical system. The light source is a halogen lamp. For example, the plane reflecting mirrors 4, 1 divided into two
1, the light rays coming from the pixel between the pixels A-C and B-C of the liquid crystal original image are divided into, for example, the following two divided plane reflecting mirrors 5 and 15.
Reflect toward. The light ray 9 from the liquid crystal original image reflected by the plane reflecting mirror 5 is focused on the screen 10 as a light ray from the virtual image 6 of the original image and the virtual image 7 of the converging optical system. Here, the pixels A and C of the original image are A ′,
Corresponds to C1 '.

Similarly, the light ray 14 from the liquid crystal original image reflected by the plane reflecting mirror 15 is emitted as a light ray from the virtual image 12 of the original image and the virtual image 13 of the converging optical system to the screen 10.
Image on. Here, the pixels B and C of the original image correspond to B'and C2 'on the screen. In this way, by making the plane reflecting mirrors 5 and 15 into split plane mirrors, the depth of the device can be made thin, and the incident angles of the light rays 8 and 14 can be made more vertical, so that the brightness of the reproduced image on the screen is uniform. You can

The optical element group 9 makes the optical path length between the divided original image group between the pixels A and C and the screen equal to the optical path length between the divided original image between the pixels B and C and the screen.
It affects only the optical path length between the specific divided original image and the screen. The optical element group 9 may be a lens group or a reflecting mirror group.

FIG. 2 is a view showing an embodiment of a mechanism for moving the split reflecting mirror in parallel and rotating it.
It is for matching C2 '. In the figure, 20 is a pinion, 21 is a rack, 22 is a pinion, 23 is a rack, 24 is a rotating shaft, 25 is a pinion, 26 is a rack, and 2
Reference numeral 7 denotes an optical path shield plate, and other parts having the same functions as those in FIG. 1 are designated by the same reference numerals.

In this embodiment, the light ray groups A-CC1 and CC2-B from the liquid crystal divided original image are clearly separated and reflected by the divided reflecting mirrors 4 and 11, and are prevented by the optical path shield plate 27 so as not to interfere with each other. It is separated. In the description of the present embodiment, the split reflecting mirrors 4 and 11 are applied, but the split reflecting mirrors 5 and 15 are used.
Of course, it can be applied to. Pinion 2 in the figure
0 and the rack 21 translate the split reflecting mirror 4 perpendicular to the plane, and the pinion 22 and the rack 23 translate the split reflecting mirror 4 parallel to the plane. Rotation axis 2 for split reflector 11
4 can be rotated by the pinion 25 and the rack 26.

These translation and rotation mechanisms in the figure are not necessarily limited to those using a pinion or a rack. By using such a translation and rotation mechanism, the projected images of the optical path groups A-CC1 and CC2-B from the liquid crystal divided original image can be changed independently from each other, and the divided projected image groups on the screen 10 are combined to obtain the original image. It can be reproduced as an image similar to the original image.

FIG. 3 is a diagram showing an embodiment relating to the formation of a liquid crystal original image of the present invention. Here, AB is a point on a typical horizontal scanning line, the original image is divided into two or more original image groups, and the pixels on the D1 line and the D2 line have the same component. In order to make it easy to match the divided original images on the projected images corresponding to the D1 line and the D2 line on the screen, image portions D1-CC1 and CC2-D that overlap each other on the screen
2

FIGS. 4 (a) to 4 (c) are sectional views of a liquid crystal plate and a filter for forming a divided original image, and FIG. 4 (a).
Is a cross-sectional view of the liquid crystal portion sandwiched between glass plates of the liquid crystal plate that creates the original image, FIG. 4B is a filter applied to the original image A-CC1, and FIG. 4C is an original image CC2-B. The filters to be applied are shown. Here, the separated ray groups A-CC1 and CC2-B shown in FIG. 2 are composed of light from the pixels from point A to point CC1 and light from the pixels from point CC2 to point B, respectively. It

4 (b) and 4 (c), a filter that smoothly changes optically or electrically on the pixels from the point A to the point CC1 and a pixel from the point CC2 to the point B is applied. It shows a filter that changes smoothly optically or electrically. Here, it is the light from the point D of the liquid crystal original image that the lights from the two light ray groups match on the screen as a projection image. The light intensity of the image of the point D1 between the points A-CC1 and the light intensity of the image of the point D2 between the points CC2-B is the same as the light intensity of the image formed by projecting without dividing the original image. To By using the original image and the filter having such a configuration, it is possible to superimpose the divided projection image group on the screen without a feeling of strangeness.

[0019]

As is apparent from the above description, according to the present invention, the original image is divided, and the divided projection image group is superposed and synthesized on the screen. Therefore, the depth of the liquid crystal image projection apparatus is thinned. Further, since the image of the original image projected on the screen is dispersed, the light intensity distribution of the reproduced image on the screen can be made more uniform.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of an image projection apparatus according to the present invention.

FIG. 2 is a diagram showing a mechanism for translating and rotating the split reflecting mirror in the present invention.

FIG. 3 is a diagram showing an example relating to formation of a liquid crystal original image in the present invention.

FIG. 4 is a diagram showing a cross-sectional view and a filter of a liquid crystal plate for creating a divided original image in the present invention.

FIG. 5 is a configuration diagram of a rear projection device using a conventional liquid crystal.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal panel, 2 ... Converging lens system, 3 ... Light source and condensing mirror, 4, 5 ... Planar reflecting mirror (divided reflecting mirror), 6, 7 ... Virtual image, 8 ... Rays, 9 ... Optical element group, 10 ... Screen, 1
1, 15 ... Planar reflecting mirrors (divided reflecting mirrors), 12, 13 ... Virtual images, 14, 16 ... Rays.

Claims (6)

[Claims] 1. An image projection apparatus for projecting an original image on a screen, wherein a liquid crystal panel on which the original image is formed and a plane reflection of an imaging optical system for reflecting light rays coming from pixels of the liquid crystal panel are provided. An image projection apparatus comprising: a group of flat reflecting mirrors divided into a plurality of groups; and a screen for forming an image of light rays from the group of flat reflecting mirrors. 2. The image according to claim 1, further comprising an optical system for dividing a group of divided images corresponding to a boundary of the plane reflecting mirror group to form an original image on a screen. Projection device. 3. An optical element group for matching an optical path length from a part of the divided original images with an optical path length from the remaining divided original images among the divided original image groups. 1. The image projection device according to 1. 4. An adjusting mechanism system for translating and rotating the plane reflecting mirror group in order to synthesize a divided projection image group formed by forming the divided original image group on a screen. 1. The image projection device according to 1. 5. The image projection apparatus according to claim 1, wherein the joint portions between the divided original images have a value in which the same pixel is filtered in a portion where the joint portions overlap each other. 6. The image projection apparatus according to claim 1, further comprising an optical path blocking plate so that light beams between the divided original images do not interfere with each other in the projection optical path.