JPS63216025A - Projection type color display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a liquid crystal light valve for image formation. The present invention relates to a projection type color display device that uses M number of images and displays images by projecting them.

[Conventional technology]

Conventionally, projection type color display devices using multiple sheets of liquid crystal light pulp are SID'80 Digest P375-P.
As described in 378, a dichroic mirror system in which white light is combined in a cross shape is used to separate the three primary colors of red, green, and blue color light, and the color light is image-modulated by a liquid crystal light valve, and each color light is converted into a grid. There was one that combined images using an ichroic prism and projected them using a projection lens.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional technology, it is difficult to realize a perfectly parallel light projection light source, and the attenuation increases as the distance from the light source increases. In the previous example, the distance from the light source of red light and blue light to the liquid crystal light valve is larger than that of green light, so in addition, due to the anti-QJ = error, the attenuation of red light and blue light is large, and the green light is attenuated by an ND filter, etc. This results in a dark image display.

Therefore, the present invention aims to solve these problems.
The purpose of this is that dichroic mirrors that convert white light source light into colored light molecules are arranged in series to emit and separate each color light in the same direction, and each color light is divided into the effective screen size of the light valve. The purpose is to provide a bright image by emitting colored light from the lamp exit surface to the light valve surface using a leading wave tube that has approximately the same cross-sectional area.

[Means for solving problems]

The projection type color display device of the present invention includes a light valve for image formation, a dichroic mirror for separating and combining color light, a projection optical system, and an illumination system. , blue, and green color light are arranged in series to reflect and separate each color light in the same direction, and each color light is a leading wave whose cross-sectional area is approximately equal to the effective screen size of the light valve. It is characterized by a tube that guides colored light from the lamp output surface to the light valve surface.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a principle diagram showing the basic principle of a leading wave tube of a projection type color display device of the present invention.

The light source 1 is a lamp such as a halogen lamp or an xe clamp metal halide lamp, and the reflector 2 is constituted by a long 4n circle or a parabolic mirror, and irradiates the light bulb 3 with the light beam emitted from the lamp as efficiently as possible. The light valve 3 is a light modulation element, a liquid crystal panel, PLZT
, a magnetophoretic element or the like (1'rI is formed), and an image such as an image or a character is formed by electrically varying the amount of light transmitted, and the image is enlarged by the projection/zoom 4. The image forming portion 5 is constituted by a rectangular image surface, similar to a cathode ray tube of a normal television, and the aspect ratio of the screen is 3:4.

The leading wave tube 6 is an optical four-wave tube having a cross-sectional area almost the same as the rectangular area of the image-forming portion 5, and its inner surface is finished with a mirror finish that has a particularly high reflectance. The optical waveguide 6 guides the direct light 7 emitted from the light source 1 to the light valve 3 through the inner reflection surface of the four-wavelength optical waveguide 6 . Therefore direct light 7
The luminous flux utilization rate is increased. In addition, the light 8 reflected by the reflector 2 ideally has a high luminous flux that irradiates the light valve 3, but since the light source 1 itself is not a point light source, there are many stray light components, and these are absorbed by the light valve surface by the optical waveguide. This leads to an improvement in the output luminous flux.

FIG. 2 is a block diagram showing an embodiment of the projection type color display device of the present invention.

The white light emitted from the light source 10 is separated into colored lights by dichroic mirrors having different selective reflection characteristics in the same direction. The blue reflecting mirror 11 is arranged so as to be the shortest distance from the light source 10, and irradiates the light valve 12 for blue light. The green reflecting mirror 13 reflects the green light and irradiates the light valve 14 for green light. Since the reflecting mirror 15 reflects blue light and colored light other than the inverted green light, that is, red light, it may be an ordinary reflecting mirror and irradiates the light valve 16 for red light. The projection lens 17 enlarges and projects the image created on the light valve surface using lenses designed to match blue, green, and red color lights, and synthesizes each color light on the screen. The four-wave optical tube 18 is a waveguide whose cross-sectional area is approximately the same as the effective screen portion (shaded area) of the light valve, and whose inner surface is mirror-finished. Therefore, the blue light bulb close to the light beam IO and the red light bulb located at a longer distance can sufficiently capture the incident light of the red light bulb 16, where the effect of the optical 4-wave tube is attenuated due to the longer distance. becomes possible.

FIG. 3 is a block diagram showing another embodiment of the projection type color display device of the present invention, in which (a) is a plan view and (b) is a side view.

The white light emitted from the light source 20 enters a color separation dichroic mirror tilted at 45 degrees with respect to the incident light, and is separated into each color light by a blue light reflecting mirror 21, a green light reflecting mirror 22, and a red light reflecting mirror 23. be done.

The blue light reflecting mirror 21 reflects blue light and transmits other light. The reflected blue light is guided by the leading wave tube 24 and is condensed and irradiated onto the effective screen area of the blue light light valve 25 .

Blue light return port (light transmitted through mirror 21 is passed through green light return port 1
The light enters the mirror 22, reflects the green light, and transmits the other light, the red light. The reflected green light is focused and irradiated onto the effective screen area of the green light light valve 2G.

The red light that has passed through the green light reflecting mirror is reflected by the red light reflecting mirror 23 and guided to the effective screen area of the red light bulb 27 by the leading wave tube 24 .

Each of the light valves corresponding to red, green, and blue color lights controls the amount of light transmitted by an electric signal of the image, and each color light is synthesized into an image by the cube prism 28. This Teub prism 28 is made by gluing together four rectangular prisms in which a guichroic layer is formed using a steam tube on the surfaces sandwiching the right angle. In other words, X
By providing reflective surfaces with red reflective characteristics and blue reflective characteristics in the shape, it is possible to synthesize each color of light, and the projection lens 29
The image is enlarged and projected onto the screen 30.

Since the leading wave tube 24 is a four-wave tube with a mirror-finished inner surface that has the same cross-sectional area as the irradiation surface area of the light valve, direct light and stray light components can be guided to the light valve entrance surface.

〔Effect of the invention〕

As described above, according to the present invention, using an optical waveguide,
By guiding the light through the light valve with a cross-sectional area that is almost the same as the video screen area, the output luminous flux can be significantly increased, and the projected image will be brighter in the center and periphery. Significant improvement was also seen for different illuminance unevenness. In addition, dichroic mirrors that use one light source and separate red, blue, and green light are arranged in series so that each light is spaced apart by 9 minutes in the same direction.
It has become possible to improve color separation performance, and by changing the optical path length, it has also become possible to correct the color temperature of the white color of the image, which previously depended on the wavelength characteristics of the light source.

In addition, by guiding the optical waveguide close to the light valve, the cube prism can be made approximately the same size as the light valve's effective WJ surface area, making it possible to reduce the aperture of the projection lens. A projection type color display device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a principle diagram showing the basic principle of a four-wave optical tube of a projection type color display device of the present invention. FIG. 2 does not show one embodiment of the projection type color display device of the present invention (M factor). In the configuration diagram shown, (a) is a plan view, (b)
is a side view. 1... Light source 2... Reflector 3... Light bulb 4... Projection lens 6... Guide wave tube 28... Cube prism or more Applicant Seiko Epson Corporation No. 1 I! 1 Second gourd.

Claims (1)

[Claims] In a projection type color display device that consists of a light valve for image formation, a dichroic mirror that separates and combines color light, a projection optical system, and an illumination system, white light source light is divided into red, red, and white light sources.
Dichroic mirrors that separate blue and green color light are arranged in series so that each color light is reflected and separated in the same direction, and each color light is transmitted through an optical waveguide with a cross-sectional area approximately equal to the effective screen size of the light valve. A projection type color display device characterized by guiding colored light from a lamp output surface to a light bulb surface.