JP2746263B2 - Color display - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color display device using a light modulation element such as a liquid crystal. [0002] Figure 1 full color table using the conventional liquid crystal
1 shows an example of a display device . Electrodes 5 on glass 1, 2
6 is provided, and the liquid crystal body 7 is driven. In addition, a color filter having the arrangement shown in (b) for color display is provided, and a white image is projected from below to obtain a color image from above. That is, the liquid crystal acts as a light valve using the light from the lower white light source to control the transmitted light of the R, G, and B color pixels, thereby realizing a full-color display. In principle, this method is realized by a combination of an electro-optical element that electrically controls the amount of transmitted light such as liquid crystal, a color filter, and a light source. Is the feature. The details of the full-color display by the light valve system are described in, for example, Nikkei Electronics, September 10, 1984, page 211, page 211, so that the details are omitted. Although this method can easily realize full-color display, it greatly depends on the efficiency (power consumption) of the backlight (white light source) and the spectral characteristics of the color filter. For example, even when a color filter is formed by dyeing an organic substance with a dye, the light absorption is improved (the filter is darkened) in order to increase the saturation. As a result, the brightness of the backlight must be gained. However, this sacrifices the low power of the liquid crystal and is not preferred. This defect is due to the fact that the color filter expresses a color by absorbing light. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a means for expressing colors with high transmittance and high saturation, instead of a color filter that generates colors by absorption. SUMMARY OF THE INVENTION The present invention provides a color display device having a single liquid crystal light modulation element having a plurality of red light pixels, blue light pixels, and green light pixels. And
A plurality of lenses for condensing light from the light source, and a plurality of spectroscopic means for separating the light condensed by each of the plurality of lenses into light of three primary colors and leading the light to the pixel for the corresponding color light, It is characterized by comprising. FIG. 2 shows a basic conceptual diagram of the present invention. Glass 1
Liquid crystals 16 are sealed at 0 and 11 via a spacer 12. Of course, the electrodes 13 and 14 are formed on the glass 10 and 11, and are basically the same as the conventional one. The fundamental difference is that instead of the color filter, the flat multi-pixel spectral plate 1
5 is to be used. Although the light-splitting plate is disposed outside the liquid crystal panel in this figure, the light-splitting plate can be formed into a shape close to that shown in FIG. The flat multi-pixel dispersing plate 15 separates, for example, white light from below into R, G, and B components, and apparently obtains a planar arrangement as shown in FIG. As a result, conventionally, for example, the R pixel absorbs the B and G components and transmits only the R component.
The ingredients are wasted. On the other hand, in the present invention, since each pixel of R, G, and B crosses by demultiplexing without absorbing R, G, and B, the brightness of each pixel when the same amount of light is incident is at least three times, usually, About 5 times brighter. [Embodiment 1] FIG. 3 shows an embodiment of a flat multi-pixel spectral plate of the present invention. It consists of a microlens array 22, a corresponding microprism array 21, and a planar integrated waveguide 20. The white light from below is converged toward the center by the microlens array 22 and enters the microprism array 21. In this prism array, the R component bends less and the B component increases due to the refractive index dependence of the wavelength. Accordingly, when a planar integrated waveguide 20 such as a rod lens array is placed in accordance with the position of each component separated, white light is separated into R, G, and B outputs at the exit of this waveguide. This scheme is brighter than conventional color filters, since in principle there is no absorption (no loss) in this optical path.
The basis of this configuration lies in the use of the microprism array 21. The other portions do not have to sacrifice some efficiency, and can be replaced with other devices having the same function. The components shown here can be easily formed based primarily on plastic materials. The material is an acrylic or polycarbonate resin, which is formed by injection molding. Looking at this planar multi-pixel spectral plate from above, R,
G and B color pixels are formed, and by overlapping a light valve such as a liquid crystal display in which the pixels are aligned with the color pixels, a color image brighter than before can be reproduced. [Embodiment 2] FIG. 4 shows another embodiment. Microlens array 31 and planar integrated waveguide 30
3 is the same as that in FIG. 3, and when the incident direction of light is limited or the viewing direction is limited, as in the example of FIG. 3, it can be omitted or replaced with another one. This method uses a spectral mirror 34.35 and a double-sided mirror 32,
33. First, the incident white light reflects the R component by the spectroscopic mirror 35 and is bent to the left, so that the double-sided mirrors 32, 3
The light is emitted to the R pixel by 3. On the other hand, the B and G components pass through the spectral mirror 38 and enter the next spectral mirror 34. At this time, the G component is reflected to the left by the spectroscopic mirror 34 and exits as a G component. On the other hand, the B component passes through the spectral mirror 34 and is emitted as the B component. As a result, when observed from above, the incident white light is R, G, B
Are separated into the respective components, so that a fine color pixel can be formed. The basic configuration of the spectroscopic mirror used here is the same as that of a conventional dichroic mirror, or it is sufficient even if the performance is slightly inferior. The flat-panel and other-pixel dispersing plate of the embodiment shown here can be formed of a plastic material. For example, the double-sided mirrors 32 and 33 may be obtained by depositing aluminum or the like on both sides of the block 36, and the dichroic mirrors 34 and 35 may be obtained by forming dielectric films on both sides of the block 37. By combining the blocks 36 and 37, a planar integrated spectral plate can be realized. As shown in the above embodiment, the incident light can be transmitted without loss by using a planar multi-pixel spectral plate in which a plurality of elements having the function of demultiplexing and separating each component of RGB are integrated on a plane. As a result, in order to obtain a full-color display device having the same brightness as the conventional one, the brightness of the backlight can be reduced to about 1/5 of the conventional one. This value is in a range that can be achieved with ordinary room light, that is, a range in which light-receiving type full-color display can be realized. If a backlight having the same brightness as the conventional one is used, it is needless to say that five times the brightness of the conventional one can be obtained. As described above, the present invention is directed to a color display having a single liquid crystal light modulation element having a plurality of red light pixels, blue light pixels, and green light pixels. In a display device, a plurality of lenses for condensing light from a light source, and the light condensed by each of the plurality of lenses is separated into light of three primary colors, respectively, to the pixels for corresponding color light. By providing a plurality of light-splitting means for guiding, it is possible to improve the light use efficiency and to prevent color bleeding and decrease in contrast, so that a color display device with a bright image and high image quality is obtained. It becomes possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 (a) conventional full color using a color filter
-A diagram showing an example of realizing the display device , and (b) a diagram showing a color filter. FIG. 2 is a basic configuration diagram of a display using a liquid crystal light valve of the present invention. FIG. 3 is a diagram showing a configuration example of a flat multi-pixel spectral plate used in the present invention. FIG. 4 is a diagram showing another example of realizing a flat multi-pixel spectral plate used in the present invention. [Description of Signs] 1, 2, 10, 11 ... Glass 5, 6, 13, 14 ... Driving electrodes 7, 16 ... Liquid crystal 4 ... Color filter 17 ... Light bulb 15: Planar polyhedral element dispersing plates 20, 30 Planar integrated waveguide 21: Microbrism arrays 22, 31, Micro lens array

Claims (1)

(57) [Claims] A color display device including a single liquid crystal light modulation element having a plurality of pixels for red light, a pixel for blue light, and a pixel for green light, and a plurality of lenses for condensing light from a light source. A color display device comprising: a plurality of light splitting means for separating light condensed by each of the plurality of lenses into light of three primary colors, respectively, and leading the light to the pixel for a corresponding color light. . 2. 2. A color display device according to claim 1, wherein said spectral means comprises a prism. 3. 2. The color display device according to claim 1, wherein the spectral unit includes a spectral mirror. 4. 4. The color display device according to claim 3, wherein said light splitting means includes two light splitting mirrors and one reflection mirror.