JP3078551B2 - Reflective display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] As a display device for a projection television, a CRT is used.
A projection tube, a transparent liquid crystal light valve, and the like are used. In particular, the liquid crystal light valve type has advantages such as small size, light weight, low cost, and operability capacity as compared with a projector using a CRT. Although projectors using reflective display elements have not yet been put to practical use, their commercialization is expected in the future. The present invention relates to a reflective display device applicable to a projector or the like.

[Conventional technology]

FIG. 4 shows a conventional example of a reflection type display device proposed for a color liquid crystal projector. First polarization 1 and second polarization
To the polarization beam splitter 7, the second polarization is removed, and only the first polarization splits the first color separation mirror 45.
, And the first primary color 46 of the first polarized light is incident on the reflective polarization modulation element 41 for the first primary color and is modulated. The light other than the first primary color is incident on the second color separation mirror 44,
Of the primary color 47 is incident on the reflective polarization modulation element 42 for the second primary color,
The third primary color 48 of the first polarized light is incident on the reflective polarization modulation element 43 for the third primary color and is modulated respectively. The modulated lights of these three primary colors are combined by the color separation mirrors 44 and 45, and emitted by the polarizing beam splitter 7 as the first polarized light 3 at an angle different from that of the incident light. The unpolarized light of the first polarization reverses its original path as indicated by the broken line 5 and returns to the incident light direction.

[Problems to be solved by the invention]

The drawback of the prior art is, first of all, that the light use efficiency is low. As shown in FIG. 4, the second polarized light 2 is not used at all. Light utilization efficiency is very important in a projector. Further, since there is only one light modulation path, there is little information. For example, displaying a stereoscopic image requires another identical device.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a reflection-type display device capable of improving light use efficiency and capable of performing stereoscopic display and high-quality color display.

[Means for solving the problem]

According to the present invention, a polarization beam splitter for separating first and second polarizations of incident light, and a first reflection beam disposed on an optical path of the first polarization separated by the polarization beam splitter are provided. Polarization modulator and a second polarization modulator disposed on the optical path of the second polarized light separated by the polarization beam splitter.
And a reflection type polarization modulation element. The modulated light of the first polarized light and the modulated light of the second polarized light modulated by the respective reflection-type polarization modulation elements are combined by the polarization beam splitter and emitted at an angle different from that of the incident light. The first reflection-type polarization modulation element and the second reflection-type polarization modulation element are based on left and right image signals, respectively.
By modulating the second polarized light and the second polarized light, the emitted light can be stereoscopically viewed by polarized glasses. The first reflection type polarization modulation element and the second reflection type polarization modulation element are color reflection type polarization modulation elements capable of individually modulating color information of three primary colors, thereby enabling color stereoscopic viewing. . Although not stereoscopic, the first reflective polarization modulator can modulate colorless or monochromatic light, and the second reflective polarization modulator can modulate color information of three primary colors individually. By using a color reflection type polarization modulation element, it is also possible to realize a reflection type display device having both saturation and brightness with a simple configuration.

〔Example〕

The present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the reflection type display device of the present invention. The first polarized light 1 and the second polarized light 2 which are incident lights enter the polarizing beam splitter 7, and the first polarized light 1 separated by the polarizing beam splitter 7 is the first polarized light 1 arranged on the optical path. The light enters the reflection type polarization modulation element 8 and is polarization-modulated. The second polarized light 2 separated by the polarization beam splitter 7 is polarization-modulated by a second reflection-type polarization modulation element 9 arranged on the optical path. The respective modulated lights are combined by the polarization beam splitter 7, and the first modulated light is formed at a different angle from the incident light.
Are emitted as the modulated light 3 of the second polarization and the modulated light 4 of the second polarization. The emitted light is collected by a lens 10 and projected on a screen 11. If the first and second reflection-type polarization modulation elements modulate using stereoscopic image signals corresponding to the left and right eyes, a stereoscopic image can be easily obtained by viewing the screen with polarizing glasses. When a stereoscopic image is not viewed, an image that is twice as bright as the conventional example can be obtained by inputting the same signal to the two reflection-type polarization modulation elements. Here, the electric field control birefringence mode of the liquid crystal may be used as the reflection type polarization modulation element. As the electric field control birefringence mode, a homeotropic type in which the initial orientation is substantially perpendicular to the substrate, a hybrid type in which one substrate surface is vertical and the other substrate surface is parallel, and a planar type in which both substrate surfaces are substantially parallel ( (Including twist) and a two-state utilizing type of ferroelectric liquid crystal. As a drive, either a simple matrix or an active matrix can be used, and a monolithic type in which an active matrix circuit and peripheral circuits are integrated on a silicon substrate is most suitable.

 FIG. 2 shows a second embodiment of the present invention.

The first reflection type polarization modulation element 8 and the second reflection type polarization modulation element 9 of this embodiment are color reflection type polarization modulation elements capable of individually modulating color information of three primary colors. Each of the color reflection type polarization modulation elements is provided with a color separation prism 21 or 22 which is means for separating the first, second, and third primary colors, respectively, and a first color separation prism provided for each of the primary colors. It comprises primary-color reflective polarization modulators 23 and 26, second primary-color reflective polarization modulators 24 and 27, and third primary-color reflective polarization modulators 25 and 28. As in the first embodiment, if the first and second color reflection type polarization modulators 8 and 9 modulate using the stereoscopic image signals corresponding to the left and right eyes, the screen can be viewed with polarized glasses. Thus, a stereoscopic image can be easily obtained. If you do not see a 3D image, 2
By inputting the same signal to the two color reflection type polarization modulation elements 8 and 9, an image twice as bright as the conventional example can be obtained.

 FIG. 3 shows a third embodiment of the present invention.

The first reflection type polarization modulation element 8 of this embodiment is a reflection type polarization modulation element that modulates colorless or monochromatic light, and the second reflection type polarization modulation element 9 can individually modulate the color information of the three primary colors RGB. It is a color reflection type polarization modulation element. If a colorless (white; W) device is used as the first reflection type polarization modulation element 8, a so-called RGBW type display is possible. As shown in FIG. It is possible to realize a reflection type display device that achieves both brightness.

〔The invention's effect〕

As is clear from the above description, the present invention enables a highly efficient and high-performance display device which has never existed in the past, and an extremely high-performance projector or the like can be provided by using the present invention.

[Brief description of the drawings]

FIGS. 1, 2, and 3 are explanatory diagrams each showing an embodiment of the reflective display device of the present invention, and FIG. 4 is an explanatory diagram showing an example of a conventional reflective display device. 1 ... first polarized light, 2 ... second polarized light, 3 ... modulated light of first polarized light, 4 ... modulated light of second polarized light, 7 ... polarized beam splitter, 8 ... first 9. The reflection type polarization modulation element of 9... The second reflection type polarization modulation element.

Claims (2)

(57) [Claims] 1. A polarizing beam splitter for separating a first polarized light and a second polarized light of incident light, and a colorless or monochromatic light disposed on an optical path of the first polarized light separated by the polarizing beam splitter. A monochromatic reflective polarization modulation element for modulating,
A color reflection type polarization modulation element provided with a color separation mirror arranged on the optical path of the second polarized light separated by the polarization beam splitter and capable of individually modulating the color information of the three primary colors. A reflective display device, wherein modulated light of a first polarized light and modulated light of a second polarized light modulated by a polarization modulator are combined by the beam splitter and emitted at an angle different from that of the incident light. 2. The reflection type display device according to claim 1, wherein the reflection type polarization modulation element is a liquid crystal reflection type polarization modulation element in which birefringence of liquid crystal is controlled by an electric field.