JP2000275736A - Directional reflection screen and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the viewing range for apprication in the horizontal direction of an image display device which uses a group of laminated mirrors. SOLUTION: The directional reflection Screen 10 consists of a group of laminated mirrors 10A and a holographic element 10B which diffuses the incident light to the ridge line direction of the reflection mirrors by diffraction of the pattern formed on tbe substrate surface of the element. Thereby, the viewing range for apprication in the horizontal direction can be increased for an image display device using a group of reflection mirrors which is especially suitable as a stereoscopic imaging device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a directional reflection screen which enables stereoscopic viewing using binocular parallax without wearing special glasses, and an image display apparatus suitable for displaying a stereoscopic image using the same. .

[0002]

2. Description of the Related Art Conventionally, without wearing special glasses,
2. Description of the Related Art As an image display apparatus that enables stereoscopic viewing using binocular parallax, an apparatus that combines an image projection unit and a directional reflection or transmission screen is known. As such a device, a directional reflection screen using a mirror group in accordance with a light condensing means in a horizontal direction for a viewer is described in, for example, Takayoshi Ohkoshi, "3D Image Engineering (Asakura Shoten)", pages 28 and 91-91.
Page 97.

[0003] These are shown in FIGS. 2 and 11. In the screen shown in FIG. 2, light is condensed in the horizontal direction by a two-plane orthogonally aligned mirror group 1, and diffused in the vertical direction due to the unevenness 2 added to the mirror surface. Further, in the screen shown in FIG. 11, the diffusing property is given in the vertical direction by the lens effect of the semi-cylindrical lens group 3 combined with the two-plane orthogonal mirror group 1.

[0004] In the two-plane orthogonal alignment mirror group, as shown in FIG. 3, light rays are reflected in the incident direction. Therefore, as shown in FIG. 4, in an image display device in which image projection means 11L and 11R for left and right eyes, for example, composed of a liquid crystal projector or the like and the directional reflection screen 10 shown in FIGS. , Each image projection means 1
When the video signals emitted by 1L and 11R are reflected by the directional reflection screen 10, they are condensed in the horizontal direction at the positions of the respective image projection units 11L and 11R. Taking advantage of such a reflection characteristic of the screen 10, the two image projection means 11L and 11R are arranged immediately above or immediately below the right and left eyes of the viewer 12, and a three-dimensional image signal based on the principle of binocular parallax is also provided. By irradiating a pair of video signals, a stereoscopic video can be viewed without wearing special glasses.

[0006] As shown in FIG. 6, these directional reflection screens 10 each include three or more image projection units 11.
L, 11R, 13L, and 13R, and by projecting a parallax image corresponding to the projection position from each image projection unit, when the viewer 12 moves in the horizontal direction, another two image projection units 3D can be viewed while viewing the image of
For this reason, the viewing range of the entire apparatus can be expanded. Such a stereoscopic image display device is called a multi-view stereoscopic image display device.

[0006]

The prior art image display apparatus described above has a problem that the viewing range is narrow because the horizontal light condensing property of the screen is strong. Further, in the conventional multi-view stereoscopic image display device, when the viewer moves in the horizontal direction and moves to the viewing range of another image projection unit, there is a problem that an area where the image cannot be viewed occurs. Further, in the image display device of the related art, there is a problem that light emitted from the image projecting means and reflected on the screen surface becomes stray light and becomes noise on a screen.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. The present invention is directed to a mirror which combines a directional reflection screen with a mirror group and diffracts incident light by diffraction of a pattern formed on a substrate surface. And a holographic element that diffuses in the direction of the ridge line.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of a stereoscopic image display apparatus according to one embodiment of the present invention is shown in FIGS. The stereoscopic image display device of the present embodiment includes image projection means 11L and 11R and a directional reflection screen 10 which are arranged at a distance between both eyes in the horizontal direction. The directional reflection screen 10 includes the group of mirrors 1
0A and diffraction of the pattern formed on the substrate surface,
It consists of a holographic element 10B that diffuses the incident light in the direction of the ridgeline of the mirror. The image signals projected from the image projection means 11L and 11R are output from the holographic element 10B.
After being transmitted through the holographic element 10B again after being reflected by the group of mirrors 10A, the light is guided to the right and left eyes of the viewer 12.

In the holographic element 10B, incident light can be diffused in the direction perpendicular to the ridgeline of the aligning mirror by designing the surface pattern and setting the angle of alignment between the aligning mirror group 10A and the holographic element 10B. The direction perpendicular to the ridge line of the mirror is a direction perpendicular to the viewer. When the diffusion angle in this direction is increased on the screen 10, the viewing range of each projected image in the horizontal direction is increased in the image display device. Will be done. A larger viewing range in the horizontal direction of the image display device is preferable because a better viewing environment can be provided to the viewer.

However, in the image display device of the present invention, when the viewing range of the image signal emitted from each image projection means exceeds the binocular interval of the viewer 12, the right-eye image and the left-eye image are mixed. So-called crosstalk occurs, making stereoscopic vision difficult. Therefore, the viewing range of each image signal in the horizontal direction is preferably set to the distance between both eyes of the viewer.

According to page 79 of "Human Body Size Data Collection for Designers" (published by the Human Life Science Research Center), the distance between human eyes is 49 mm to 70 mm. Therefore, it is preferable that the viewing range of the image projection means in the horizontal direction is 49 mm to 70 mm. In the present image display device, the horizontal viewing range of each image signal is the horizontal viewing range R of the image projection means, the horizontal diffusion angle θ of the screen, the distance L between the screen center and the viewer, the emission light width. It can be expressed as Equation 1 using W.

[0012]

R = W + 2Ltan (θ / 2) (1) Accordingly, the diffusion width θ of the screen is represented by the following expression (2).

[0013]

## EQU2 ## θ = 2 tan ⁻¹ ((R−W) / 2L) (2) In the present image display device, the distance L between the center of the screen and the viewer.
Is from 500 mm to 10000 mm. Also, the output light width W
Is 10 to 40 mm. Therefore, the diffusion angle θ in the direction perpendicular to the ridgeline of the mirror for the screen is preferably 0.05 to 7 degrees.

In the ridge direction of the mirror, Equation 3 holds between the viewing range Rv in the ridge direction of the mirror and the diffusion angle θv in the ridge direction of the screen, as in the equation (2).

[0015]

[Equation 3] θv = 2 tan ⁻¹ ((Rv−W) / 2L) (3) The viewing range Rv in the ridgeline direction of the mirror is 200 mm to 100 mm.
About 0 mm is preferable. Therefore, it is preferable that the diffusion angle θ in the direction of the ridge line of the mirror of the screen be 0.9 to 89 degrees.

When the surface of the holographic element 10B on which the pattern of the holographic element 10B is formed is formed on the surface of the viewer 12 as shown in FIG. 8, the surface becomes a diffuse reflection surface, so that stray light components due to specular reflection are reduced. It is possible and suitable.

Here, when the included angle of the group of mirrors 10A is 90 degrees, the focusing position of one image projection means 11 is 1
Thus, a stereoscopic image display device for one person can be configured. When the included angle is not 90 degrees, the light condensing positions are two points, and a stereoscopic image display device for two persons is obtained as shown in FIG.

If the group of mirrors is configured such that a plurality of mirrors having different included angles are periodically arranged, a focusing position almost twice as many as the number of included elements can be obtained. This makes it possible to obtain a stereoscopic image display device that allows more viewers to view at the same time.

Here, in the case of a screen including a component in which the included angle of the mirror is not 90 degrees, as shown in FIG.
If 0A is formed so as to be concave in the ridgeline direction, the shift of the light collecting position due to the difference in the horizontal reflection position on the screen 10 is corrected. If the radius of curvature at this time is set to a half of the distance between the exit lens (not shown) of the image projection means 11 and the center of the screen, the horizontal light condensing position becomes one point, which is preferable.

Further, as shown in FIG. 10, when the directional reflection screen 10 is made concave in the direction perpendicular to the ridgeline of the mirror group, the reflected light is condensed in the vertical direction. The area where the reflected light overlaps at the viewing position, that is, the area where the entire screen can be viewed is widened, which is preferable. Here, it is preferable that the radius of curvature of the screen 10 coincide with the distance between the image projecting means 11 and the center of the screen 10 because the reflected light completely overlaps at the viewing position regardless of the reflection position of the screen.

When these concave shapes are formed, it is preferable to form the base of the group of mirrors made of a polymer material because the processing is facilitated.

Further, as shown in FIG.
0, a lens sheet 10C made of a Fresnel lens or the like having a light condensing action in the ridgeline direction of the mirror is included.
The reflected light can be condensed in the direction perpendicular to the ridge of the mirror,
A region where the reflected light overlaps at the viewing position regardless of the reflection position of the screen 10, that is, a region where the entire screen can be viewed is widened, which is preferable. Here, it is preferable that the focal length of the lens sheet 10C be equal to the distance between the image projecting means 11 and the center of the screen 10, since the reflected light completely overlaps at the viewing position regardless of the reflection position of the screen.

The present invention is particularly effective in a multi-view stereoscopic image display device as shown in FIG. In this case, the viewing range can be expanded as the number of image display means increases, but in the present apparatus, the number of image projection means is equal to the number of necessary images. Increase. For this reason, especially when displaying a moving image, many image calculations are required. Therefore, the actual number of image projection means is suitably 4 to 8.

Although the three-dimensional image display device has been described above, the present invention is not limited to the three-dimensional image display device as described above, and is limited even when a single image projection device is used as image projection means. An image display device suitable for an amusement or the like in which a viewer can view an image at a viewing position can be provided.

[0025]

According to the present invention, the viewing range in the horizontal direction of an image display device using a group of mirrors particularly suitable for a stereoscopic image device can be extended.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing the structure of an image display device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a main part showing a structure of a directional reflection screen according to the related art.

FIG. 3 is an explanatory diagram showing ray trajectories of a group of mirrors.

FIG. 4 is a schematic top view showing the structure of a conventional image display device.

FIG. 5 is a schematic top view showing the structure of an image display device according to one embodiment of the present invention.

FIG. 6 is a schematic top view showing the structure of a conventional image display device.

FIG. 7 is a schematic top view showing the structure of an image display device according to one embodiment of the present invention.

FIG. 8 is a schematic side view showing the structure of an image display device according to one embodiment of the present invention.

FIG. 9 is a schematic top view showing the structure of an image display device according to one embodiment of the present invention.

FIG. 10 is a schematic side view showing the structure of an image display device according to one embodiment of the present invention.

FIG. 11 is a schematic diagram showing the structure of a directional reflection screen according to the related art.

FIG. 12 is a schematic side view showing the structure of an image display device according to one embodiment of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03B 35/18 G03B 35/18 5C061 G09F 9/00 360 G09F 9/00 360K 5G435 H04N 5/74 H04N 5 / 74 C 13/04 13/04 (72) Inventor Akira Arimoto 1-280 Higashi-Koigakubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. F-term in Hitachi Central Research Laboratory (reference) 2H021 BA01 BA02 BA03 2H042 DA11 DB08 DD01 DD05 DE00 2H049 CA01 CA05 CA09 CA16 CA22 2H059 AA24 AA38 5C058 AA18 BA35 EA02 EA33 EA34 5C061 AA06 AA23 5G435 BB46 FF11

Claims (12)

[Claims] 1. A directional reflection screen comprising a group of mirrors and a holographic element for diffusing incident light in the direction of the ridgeline of the mirrors by diffraction of a pattern formed on the surface of the substrate. 2. The directional reflection screen according to claim 1, wherein said holographic element has a diffusivity also in a direction perpendicular to a ridgeline of said mirror. 3. The directional reflection screen according to claim 2, wherein an angle of diffusion in a direction perpendicular to a ridgeline of the aligning mirror is 0.05 to 7 degrees. 4. The directional reflection screen according to claim 1, wherein a surface of the substrate on which the pattern of the holographic element is formed is disposed on a light incident side. 5. The directional reflection screen according to claim 1, wherein the group of mirrors includes a mirror having an included angle other than 90 degrees. 6. The directional reflection screen according to claim 1, wherein said group of mirrors comprises a plurality of mirrors having a different included angle arranged periodically. 7. The directional reflection screen according to claim 1, wherein the directional reflection screen has a concave surface in a direction perpendicular to a ridge line of the aligning mirror. 8. The directional reflection screen according to claim 1, further comprising a lens sheet having a light condensing function in a direction of a ridgeline of said mirror. 9. The directional reflection screen according to claim 1, wherein said reflection mirror has a concave surface in a ridge direction of said aligning mirror. 10. The directional reflection screen according to claim 1, wherein the base of the group of mirrors is formed of a polymer material. 11. An image display device comprising the directional reflection screen according to claim 1 and image projection means. 12. The image display device according to claim 11, wherein said image projection means projects two or more images.