JPH0743664A - Projection image display device - Google Patents

Abstract

PURPOSE:To provide an image having a large angle of view to an observer not only in a horizontal direction but also in a vertical direction by specifying a ratio between lengths in the horizontal direction and the vertical direction in a part of a concave mirror whose surface is an elliptic sphere, arranging an image source in the vicinity of the focal point of the elliptic sphere, arranging the position of the eye of the observer in the vicinity of the other focal point and specifying the size of the image of the image source with respect to the outside diameter of the concave mirror. CONSTITUTION:The concave mirror 7 is shaped in a shape of a part of a nearly elliptic sphere shape. The ratio of the diameter in the horizontal direction of the concave mirror 7 to that in the vertical direction thereof is made 1:0.5-1.5. A transmission screen 6 whose diameter is made <=1/5 of the outside diameter of the concave mirror 7 is placed in the vicinity of the focal point 71 of the concave mirror 7. An observer 21 is positioned near the other focal point 72 of the concave mirror 7. By a property of an ellipse, the observer 21 positioned in the vicinity of the focal point 72 views the video on the transmission screen 6 in the vicinity of the focal point 71 by projecting it on the nearly whole concave mirror 7. Thus, the image having the angle of view large not only in the horizontal direction but also in the vertical direction is provided by one projector.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type image display apparatus capable of viewing an image of an image source as a virtual image through a reflecting mirror. In particular, the present invention relates to a projection-type image display device which is suitable for use as a game machine, an audiovisual machine, various kinds of simulation machines, and the like, and which is highly realistic and has a lot of entertainment.

[0002]

2. Description of the Related Art As a projection type image display device capable of viewing an image from an image source as a virtual image reflected on a reflecting mirror, for example, a flight simulator (engineer 274 PP
78 ~ 801991.5. Extra number).

3 and 4 are a sectional view and a top view schematically showing the structure of a conventional flight simulator. The flight simulator is basically composed of an image source 4 including a transmissive screen 2 and a projector 3, and a concave mirror 1. By focusing the light beam from the projector 3 on the transmissive screen 2 and looking at the image projected on the transmissive screen 2 through the concave mirror 1, the viewer 21 feels that the image looks far, and as if he / she boarded an airplane. It gives you a visual sense of presence.

Regarding the viewing angle, about 18 projectors are installed in the horizontal direction by installing a plurality of projectors 3 as shown in FIG.
It provides a viewing angle of 0 degrees. In contrast, the vertical direction is about 4
It is as narrow as 0 to 50 degrees. Since the flight simulator assumes the visual field from the cockpit of an airplane as an image, there was no problem even if the vertical viewing angle was narrow.

[0005]

In order to make the projection type image display apparatus suitable as a game machine, an audiovisual machine, various simulation machines, etc.,
Practicality is improved when the viewing angle in the vertical direction is wide. However, in the flight simulator, the viewing angle in the horizontal direction can be obtained close to 180 degrees as described above, but if a plurality of image sources 4 are installed in the vertical direction as in the horizontal direction to increase the viewing angle, In principle, a wide viewing angle could not be obtained because the light rays A and B to the viewer 21 were blocked by the transmission screen.

The object of the present invention is to provide 1 in both the horizontal and vertical directions.
It is an object of the present invention to provide a projection type image display device capable of obtaining a wide viewing angle of 00 degrees or more.

[0007]

In order to achieve the above object, in the present invention, the surface of the concave mirror is a part of an elliptical sphere, and the ratio of the length in the horizontal direction to the length in the vertical direction is 1: 0.5 to 1. .5,
The image source was placed near one focal point of the ellipsoid, and the position of the eyes of the viewer was placed near the other focal point. The size of the image of the image source was set to 1/5 or less of the outer diameter of the concave mirror.

[0008]

In the projection type image display device having the above structure, since the surface of the concave mirror is a part of the ellipsoid, the light beam emitted from one focus (image source) is reflected by the surface of the concave mirror and Focuses on one focus (viewer). Therefore, if there is nothing that blocks the light emitted from the video source,
It reaches the eyes of the viewer. By miniaturizing the image source, the light rays from the image source reach the eyes of the viewer without being blocked.
Therefore, the surface of the concave mirror is a part of the ellipsoidal sphere, the ratio of the length in the horizontal direction to the length in the vertical direction is 1: 0.5 to 1.5, and the image source is arranged near the focal point of the ellipsoidal sphere. By placing the eye position near the other focus and making the image size of the image source less than 1/5 of the outer diameter of the concave mirror, an image with a high angle of view is obtained not only in the horizontal direction but also in the vertical direction. be able to.

[0009]

FIG. 1 is a schematic sectional view showing the structure of a projection type image display apparatus according to an embodiment of the present invention. The light beam from the projector 3 is enlarged and projected by the fisheye lens 5 attached as a projection lens of the projector 3. The enlarged image enters from the concave side of the transmissive screen 6, forms an image on the transmissive screen 6, and projects the image on the convex side. The transmissive screen 6 has a dome shape. Video source 4
Indicates a device for displaying an image, and is a general term for the projector 3, the fisheye lens 5 and the transmissive screen 6 in this embodiment. The concave mirror 7 has a shape obtained by taking out a part of a substantially elliptic spherical shape. The ratio of the horizontal and vertical diameters of the concave mirror 7 is 1: 0.5 to 1.5. Transparent screen 6
The diameter of the concave mirror 7 is 1/5 or less of the outer diameter of the concave mirror 7.
It is located near the focal point 71 of the. The viewer 21 is located near the other focal point 72 of the concave mirror 7. In an ellipse, a light beam emitted from one focus has a property of being incident on the other focus when reflected on the ellipse. Due to this property, the image on the transmissive screen 6 in the vicinity of the focal point 71 can be seen and viewed by the viewer 21 in the vicinity of the focal point 72 by being displayed on substantially the entire surface of the concave mirror 7. As described above, it is possible to obtain an effect of using a plurality of projectors, which has been wide-angle video only in the horizontal direction, to wide-angle video not only in the horizontal direction but also in the vertical direction with one projector.

In this embodiment, the projector 3 is a liquid crystal projector or a projection tube projector that can project with the fisheye lens 5. The projection tube projector is suitable for the three-tube one-lens type because color shift of an image hardly occurs.

The transmission screen 6 has a dome shape in order to reduce image distortion. As a result, the light can enter the concave mirror 7 from the transmissive screen 6 in the horizontal and vertical directions at an angle of view of nearly 180 degrees.

FIG. 2 shows another embodiment of the present invention. 2, the same reference numerals as those in FIG. 1 represent the same parts. 2 is different from FIG. 1 in that the direct-view display 11 is used as an image source. Also in this case, by disposing a cathode ray tube surface (not shown) near the focal point 71,
The viewer 21 can enjoy images with a high angle of view both in the horizontal and vertical directions. The principle is the same as in FIG. 1, and if a cathode ray tube surface (not shown) is arranged near the focal point 71 of the concave mirror 7, the same effect can be obtained. In this case, the image source is a substantially flat surface, and when the viewer 21 views the image through the substantially elliptic concave mirror 7, the distortion becomes larger than that of the dome-shaped transmission screen 6. For this purpose, the image on the cathode ray tube surface (not shown) of the direct-view display is used after being distorted by a convergence circuit (not shown) or the like.

In the present embodiment, the direct-view display 11 is described as a cathode ray tube type, but it goes without saying that other display devices such as a liquid crystal or plasma display device are within the scope of the present invention. .

The image near the outer periphery of the transmissive screen 6 is located far from the focal point 71. Therefore, an image near the outer circumference of the transmissive screen 6 may be reflected on the outer circumference of the concave mirror 7 in a direction invisible from the vicinity of the focal point 72.
In that respect, there is no problem if the concave mirror 7 has an aspherical outer surface and is optically designed to reach the eyes of the viewer 21 at the focal point 72.

[0015]

The surface of the concave mirror is a part of an ellipsoidal sphere, the ratio of the length in the horizontal direction to the length in the vertical direction is 1: 0.5 to 1.5, and the image source is arranged near the focal point of the ellipsoidal sphere. By locating the position of the eyes of the viewer near the other focal point and making the size of the image of the image source less than 1/5 of the outer diameter of the concave mirror, the viewer can see not only the horizontal direction but also the vertical direction. Also has the effect of being able to provide images with a high angle of view.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a projection-type image display device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing another embodiment of the present invention.

FIG. 3 is a cross-sectional view of a conventional device.

FIG. 4 is a vertical cross-sectional view of a conventional device.

[Explanation of symbols]

3 ... Projector, 5 ... Fisheye lens, 6 ... Transmission screen, 7 ... Concave mirror.

Front page continuation (72) Inventor Hiroki Yoshikawa, 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa, Ltd.Video Media Research Institute, Hitachi, Ltd. (72) Inventor Kazushige Nakagawa 292, Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa In the image information system

Claims (7)

[Claims] 1. A projection type image display device comprising an image source and a concave mirror for reflecting an image from the image source, wherein the concave mirror comprises:
Position of the image source is near the focal point of the ellipsoidal sphere, which is made up of a part of a substantially ellipsoidal sphere having a ratio of the length in the horizontal direction to the length in the vertical direction of 1: 0.5 to 1.5. A projection-type image display device characterized in that is disposed near the other focus. 2. The projection type image display according to claim 1, wherein the inner surface of the concave mirror is formed of a part of a sphere, and the image source and the eyes of the viewer are arranged near the center of the sphere. apparatus. 3. The image source comprises a projector having a dome-shaped transmission screen having a size not more than 1/5 of the outer diameter of the concave mirror and a projection lens having a wide angle of view of 100 degrees or more. 2. The transmission screen is arranged in the vicinity of the focal point in a state in which light rays are incident and imaged from the concave surface side of the transmission screen and an image can be viewed from the convex surface side of the transmission screen. 2. The projection type image display device described in 2. 4. The projection type image display device according to claim 3, wherein the projection lens having a wide angle of view is a fisheye lens. 5. The projection type image display device according to claim 1, wherein the image source is a direct-view cathode ray tube. 6. The projection type image display device according to claim 1, wherein the image source is a direct-viewing type liquid crystal display. 7. The projection type image display device according to claim 1, wherein an outer peripheral portion of the concave mirror has an aspherical shape.