JPH10206757A - Projection type video display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a device and to improve the utilization efficiency of light by integrating video display and a part for projecting video images. SOLUTION: A light source 1 emits parallel light beams so as to reduce the mixing of the video images among picture elements. For a mirror surface reflection type optical modulator 2, plural fine mirror surface elements 22... are arranged in a curved surface shape provided with a prescribed curvature in vertical and horizontal directions corresponding to a picture element number and reflected light from the fine mirror surface elements 22... is magnified and projected on a screen 3 by the effect of the curved surface. It is desirable that the shape of the curved surface where the fine mirror surface elements 22... are arranged is a part of a spherical surface, a paraboloid or a rotary ellipsoid or the like so as to make the distortion of the video images small. Then, by electric signals supplied to the mirror surface reflection type optical modulator 2, the inclination angle of the reflection surface of the respective fine mirror surface elements 22... is displaced, the reflection direction of the light from the light source 1 is made selectable and the video images are displayed by utilizing that.

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 using a specular reflection type optical modulator for displaying an image.

[0002]

2. Description of the Related Art As a projection type video display device, for example,
There is a projection type liquid crystal display device that displays image data on a liquid crystal panel, irradiates light from one side of the liquid crystal panel, enlarges image light transmitted through the liquid crystal panel by a projection lens, and forms an image on a screen.

Although the projection type liquid crystal display device has an advantage that the device can be downsized, the liquid crystal panel itself has a low light transmittance, and there is a limit in increasing the brightness of a displayed image.

By the way, a large number of minute specular reflection elements are arranged in a matrix on one plane, and by changing the direction of the mirror, the specular reflection type light for turning on / off the light reflected in a predetermined direction. Modulators have been developed.

[0005] The specular reflection type light modulator is irradiated with incident light of two or more colors from different incident angles, and the inclination direction of the specular reflection element constituting each pixel of the specular reflection type light modulator is controlled by time division. A projection type image display device (see Japanese Patent Application Laid-Open No. 7-209621) in which incident light of two or more colors is reflected in the same direction, whereby color synthesis of each pixel can be performed.
A projection type using two specular reflection type optical modulators, combining a red image, a green image or a blue image formed by each specular reflection type optical modulator with a prism, and projecting a color image through a projection lens. Image display device (Japanese Patent Laid-Open No. 7-360)
No. 12) has been proposed.

[0006] The above-mentioned specular reflection type optical modulator improves the light use efficiency as compared with the liquid crystal panel, and can increase the brightness of the displayed image.

[0007]

However, in the above-mentioned apparatus, the specular reflection type optical modulator for displaying an image and the projection lens are separated, so that further miniaturization of the apparatus is hindered.

Further, there is not a small amount of light that is not incident on the projection lens from the specular reflection type optical modulator and is lost, which causes a reduction in light use efficiency.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a projection-type image display apparatus having a small size and high light use efficiency.

[0010]

According to the projection type image display apparatus of the present invention, a large number of microscopic mirror elements whose displacement angles of the reflecting surfaces are displaced are determined in the vertical and horizontal directions corresponding to the number of pixels of the image data. A mirror-reflective light modulator arranged in a curved surface having a curvature is irradiated with illumination light, the specular-reflective light modulator is modulated according to video data, and the specular-reflective light modulator is modulated according to the video data. It is characterized in that the effective reflected light of the light modulator is imaged on a screen.

Further, in the specular reflection type optical modulator, the microscopic mirror element can be arranged on a spherical surface, a paraboloid or a part of a spheroid.

As described above, the specular reflection type optical modulator used in the present invention has a large number of microscopic mirror elements arranged in a curved surface having a predetermined curvature in the vertical and horizontal directions.
Due to the effect of the curved surface, the reflected light is enlarged and projected, and the image can be enlarged and formed on the screen. A projection system using such a mirror surface has a higher light use efficiency than a projection system using a lens.

The direction of reflection of the light from the light source of each of the microscopic mirror elements can be selected by an electric signal, and an image is displayed using this.

As described above, in the specular reflection type optical modulator used in the present invention, an image display and a portion for projecting an image are integrated, so that the number of parts can be reduced and the apparatus can be downsized.

Further, by using the specular reflection type optical modulator of the present invention, a small size, high light use efficiency and high luminance projection type image display apparatus can be realized.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing the principle of the projection display apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the projection display apparatus includes a light source 1 that emits parallel light rays, a specular reflection type light modulator 2, and a screen 3 formed of a diffusion plate.

The light source 1 is configured to emit parallel rays in order to reduce the mixing of images between pixels.
For example, one consisting of a lamp and a reflector and a condenser lens arranged on the front of the same, or one that arranges an optical element on the front of a light emitting element such as a laser or a photodiode array, and focuses light from the light emitting element in parallel Is used.

The specular reflection type optical modulator 2 includes a plurality of microscopic mirror elements 22 arranged in a curved shape having predetermined curvatures in the vertical and horizontal directions corresponding to the number of pixels. Reflected light from the microscopic mirror elements 22 is projected on the screen 3 in an enlarged manner.

It is desirable that the shape of the curved surface on which the microscopic mirror elements 22 are arranged is a part of a spherical surface, a paraboloid, or a spheroid in order to reduce distortion of an image.
In this embodiment, microscopic mirror elements 22 are arranged on a part of the curved surface inside the spherical surface. It is desirable that each of the microscopic mirror elements 22 also form a part of a curved surface. For example, each of the microscopic mirror elements 22 may be flat, and the center position thereof may be the same as the curved surface.

Then, the inclination angle of the reflection surface of each of the microscopic mirror elements 22 is displaced by the electric signal given to the specular reflection type optical modulator 2, and the direction of reflection of the light from the light source 1 can be selected. The video is displayed using this.

As described above, the specular reflection type optical modulator 2 of the present invention has an integrated image display and a portion for enlarging an image, and can perform enlarged projection on the screen 3 without using a projection lens. it can.

Incidentally, the above-mentioned specular reflection type optical modulator 2
Are arranged in a curved shape, so that an image formed on the screen 3 is distorted. As a method of correcting this image distortion, a thinning process or the like is performed on an image signal for driving the microscopic mirror elements 22.
Image distortion can be solved electrically.

In the second embodiment shown in FIG. 2, a distortion correction lens 4 is inserted between the specular reflection type optical modulator 2 and the screen 3 in order to correct the image distortion on the screen 3. 3 for correcting the image distortion.

In the third embodiment shown in FIG. 3, the distortion of the image on the screen 3 is reduced by disposing the curved microscopic mirror elements 22 in an irregular size or irregularity in advance. It is configured to be removed.

The image distortion on the screen 3 can be reduced by changing the arrangement of the screen 3. When the screen 3 is arranged as in the fourth embodiment shown in FIG. 4, the image distortion is minimized.

In each of the above-described embodiments, the minute mirror elements 22 are arranged in a concave shape on a part of the spherical surface. However, the fifth embodiment shown in FIG. ,
That is, it is arranged on a part outside the spherical surface. Other points are the same as in the first embodiment,
The same components are denoted by the same reference numerals and description thereof will be omitted.

In the projection display apparatus of the present invention,
In the case of performing color display, similarly to the above-described conventional device, the specular reflection type optical modulator 2 is irradiated with incident light of two or more colors from different incident angles, and each pixel of the specular reflection type optical modulator 2 is used. The tilt direction of the constituent specular reflection elements 22 is controlled in a time-division manner to reflect incident light of two or more colors in the same direction, thereby performing color synthesis of each pixel, or three specular reflection type optical modulators 2. , The red image, the green image, or the blue image formed by each of the specular reflection type optical modulators 2 may be synthesized by a prism to form an image on a screen.

[0028]

As described above, in the specular reflection type optical modulator according to the present invention, since the image display section and the projection section are integrated, the number of components can be reduced and the apparatus can be downsized. Further, since the projection system uses a mirror, loss of light is small, and the brightness of the projection display apparatus can be increased.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing the principle of a projection display apparatus according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing the principle of a projection display apparatus according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram illustrating the principle of a projection display apparatus according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram showing the principle of a projection display apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram showing the principle of a projection display apparatus according to a fifth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Specular reflection type optical modulator 22 Micro specular reflection element 3 Screen

Claims (2)

[Claims] 1. A mirror-reflection type light in which a plurality of micro-mirror elements whose inclination angles of reflection surfaces are displaced are arranged in a curved surface having predetermined curvatures in vertical and horizontal directions corresponding to the number of pixels of video data. A modulator is irradiated with illumination light, the specular reflection type light modulator is modulated according to image data, and an effective reflection light of the specular reflection type light modulator according to the image data is imaged on a screen. A projection type video display device characterized by the above-mentioned. 2. The projection according to claim 1, wherein the specular reflection type optical modulator has a microscopic mirror element arranged in a spherical surface, a paraboloid, or a part of a spheroid. Type image display device.