JPH04110889A - Color display device - Google Patents

Abstract

PURPOSE:To offer a color display device which is improved in productivity without requiring any complex manufacturing process by superposing an EL panel which changes in color and a liquid crystal panel which forms light- transmissive areas selectively on it. CONSTITUTION:The EL panel 1 is in a flat plate shape on the whole and constituted by superposing plural EL layers which change in color to generate respective colors of, for example, R, G, and B. The liquid crystal panel 2 is superposed on the EL panel like this and this liquid crystal panel 2 forms light-transmissive areas selectively and may have matrix constitution of, for example, row and column electrodes. This constitution omits a process of manufacturing the high- density R, G, and B color filters of the liquid crystal panel 2 and the productivity is improved. Further, one light-shielding and light-transmissive areas of the liquid crystal panel are regarded as one picture element, on which a desired color can be displayed, so an excessive request for high-density integration is prevented.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a color display device.

Prior Art Typical prior art includes R (red), G (green) and B (
The LCD panel consists of one pixel using a blue) color filter, and a white E as a backlight is behind it.
It is constructed by distributing L (Electroluminescence) panels.

Problems to be Solved by the Invention In the prior art, in order to perform color display, the positioning accuracy of the fine R, GB color filter films corresponding to each of the three pixels of the liquid crystal must be considerably high, and the manufacturing process is difficult. The process is complicated and quite expensive. Also, if you use an RGB color filter, 1
Since a pixel can only express the single light colors of RG and B, the desired color can only be expressed using multiple pixels. High density integration is required.

An object of the present invention is to provide a color display device that does not require a complicated manufacturing process and has improved productivity.

Means for Solving the Problems The present invention is characterized in that it includes an EL panel that has a flat plate shape as a whole and changes color, and a liquid crystal panel that is overlapped with the EL panel and selectively forms a translucent area. This is a color display device.

Function According to the present invention, the EL panel has a flat plate shape as a whole,
An EL panel is constructed by stacking a plurality of EL layers that change color and emit light in, for example, R, G, and B colors. Further, this EL panel may be configured so that the R, G, and B colors can be changed by changing the voltage applied to the single EL layer. The EL panel may be configured to be able to change to a plurality of other colors.

In the present invention, a liquid crystal panel is stacked on such an EL panel, and this liquid crystal panel selectively forms light-shielding regions, and may have a matrix configuration of row electrodes and column electrodes, for example. Changes in the light-shielding area due to the liquid crystal panel,
By combining this with the change in the color of the emitted light from the EL panel, and further utilizing the human afterimage effect, it becomes possible to display the desired color.

According to such a configuration, the step of manufacturing high-density RG and B color filters in the liquid crystal panel described in connection with the prior art is omitted, and productivity is improved. Moreover, one light-shielding and light-transmitting area of the liquid crystal panel is treated as one pixel, and the pixel can display a desired color, which prevents unnecessary high-density integration. I can do it. In the prior art, three pixels each having R, G, and B color filters are combined to display a desired color. Therefore, even though high-density integration is required, the present invention solves this problem. The problem disappears.

Example FIG. 1 is a perspective view of an embodiment of the present invention.

A liquid crystal panel 2 is superimposed on the EL panel 1, and an image displayed in color can be viewed in the upper part of FIG. The image to be displayed is stored in a memory 3, and the contents stored in the memory 3 are read out by an EL panel control circuit 4 to drive the EL panel, and a liquid crystal display that responds to the output from the EL panel control circuit 4. The panel control circuit 5 drives and controls the liquid crystal panel 2.

A cross section of the EL panel 1 is shown in FIG.

On one surface of the glass plate 6 is a transparent fi! 7 is formed,
An insulating film 8 is formed thereon, a red light emitting layer 9 is further formed, an insulating film 10 is further formed, and a transparent intermediate electrode 11 is formed. Furthermore, an insulating film 12, a green light emitting layer 13, and an insulating film 14 are formed on this intermediate color 8i11, and further a transparent electrode 15 is formed. On this electrode 15, an insulating film 16, a blue light emitting layer 17, and an insulating layer M18 are further formed in this order, and furthermore, a back electrode 19 is formed. The red light emitting layer 9 is made of, for example, zinc sulfide and samarium fluoride. Further, the green light emitting layer 13 is made of zinc sulfide and terbium fluoride. Furthermore, the blue light emitting layer 17 is made of zinc sulfide and copper. The transparent electrode 7.1115 may consist of gallium-doped dumbbell oxide. An AC power source 20 is provided to change the brightness, chroma, etc. of the red light emitting layer 9, and an AC power source 20 is provided for the green light emitting layer 13.
1 is provided, and an AC power source 22 is further provided for the blue light emitting layer 17. The voltage, pulse width, duty, etc. of these AC power supplies 20.2122 are controlled by the control circuit I￥8.
23, and the brightness, chroma, etc. can be changed as described above. In this way, in EL panel 1,
Power supplies 20, 2 to emit R, G, and B at high speed.
1.22 output waveforms are time-divisionally supplied. The liquid crystal panel 2 uses a liquid crystal that reacts at a high speed, and this liquid crystal has, for example, a matrix structure, and selectively forms light-shielding regions, that is, makes each of a large number of pixels light-shielding or translucent. By doing so, the amount of light transmitted through the EL panel 1 can be controlled. In order to be able to express intermediate colors and brightness and darkness in a color display, the timing of the voltage change of the liquid crystal panel 2 is determined in conjunction with the timing of the change of the driving power of the EL panel 1. By using the afterimage effect, it becomes possible to express intermediate colors and brightness and darkness in color as described above. This E
The EL pie/small control circuit 4 that drives the L panel 1 includes R,
It functions to change the G and B colors. Liquid crystal pile control circuit F that drives the liquid crystal panel 2! @5 operates so as to be able to express changes in hue and brightness of the primary colors and intermediate colors of each pixel, and the liquid crystal panel control circuit 5 performs a synchronized operation in response to the output of the EL panel control circuit 4. .

For example, each pixel of the liquid crystal panel 2 has a light-shielding property and a light-transmitting property when the EL panel 1 emits red light, and the pixels of the liquid crystal panel 2 when the EL panel 1 emits green light integrally set each time when the pixel of the liquid crystal panel 2 is light-shielding and translucent, and when the EL panel 1 is emitting blue light. By doing this, it is possible to express intermediate colors and brightness.

With reference to FIG. 3 (1), the EL panel 1 is shown in FIG. 3 (1).
As shown in , the blue light emission time W1 is the red light emission time W1.
When the pixels of the liquid crystal pile 2 are made translucent for the blue emission time W1 as shown in FIG. 3(2), bright blue is expressed when the light emission time W2 and the green emission time W3 are repeated. I can do it.

Moreover, as shown in FIG. 3 (3), the blue light emission time W1
When the pixels of the liquid crystal pile 2 become translucent for a shorter period of time, a dark blue color is expressed.

Further, as shown in FIG. 3(4), each red and green light emission time W2. Less than W3) Time w21. When only w31 is translucent and the rest of the time is light-shielding, a bright yellow color can be expressed, and as shown in Figure 3 (5), the liquid crystal display for a shorter period of time than W21 and W31. If the pixels of panel 2 are translucent, it is possible to express a dark yellow color.

Further, as shown in Fig. 3 (6), the blue, red and green periods Wl, W2. By making the liquid crystal panel 2 translucent for a time shorter than W3, for example, 111, and making it light-shielding for the remaining time, it is possible to express a bright white color.
By making the pixels of the liquid crystal panel 2 translucent for a time shorter than the time Wll, dark white light can be emitted.

In addition, in order to make the primary color blue and the intermediate color violet equally bright, when emitting purple light, the translucency of the EL panel 1 or the liquid crystal panel 2 while emitting blue light is required. The sum of the time and the time when the liquid crystal panel 2 becomes transparent when the EL panel is emitting red light is constant, and the distribution of the red time and the blue time is integrated, Can create intermediate colors.

Furthermore, the EL panel control circuit 4 and the liquid crystal panel control circuit 5 are designed to enable the human eye to see desired colors.
For example, when the EL panel 1 emits blue light,
Due to the characteristics of the EL panel 1, the luminance is low, so the time during which the pixels of the EL panel 2 are translucent is lengthened. On the other hand, when the EL panel 1 emits red light for bright display, the period during which the liquid crystal panel 2 is translucent is shortened. In this way, brightness is corrected by adjusting the characteristics of the EL pile 1 and the periods during which the liquid crystal panel 20 is light-shielding and light-transmitting. Furthermore, since the reaction speed of the liquid crystal in the liquid crystal panel 2 is generally lower than the reaction speed of the light emitting layer of the EL panel, the timing of the voltage for driving the liquid crystal 2 should be set faster than the timing for driving the EL panel 1. It is also possible to do J.

As another embodiment of the present invention, the EL panel 1 may have a configuration in which the color changes depending on the voltage, or may have other configurations.

Effects of the Invention As described above, according to the present invention, a flat plate-shaped E whose color changes
Since a color display device is constructed by overlapping the L panel with a liquid crystal panel that selectively forms light-shielding areas, the light-shielding and light-transmitting areas of the liquid crystal panel are treated as one pixel, and the color of that pixel is EL. Since it varies from panel to panel, high-density fabrication steps are eliminated and productivity is improved compared to the configuration using R, G, B color filters in the prior art described above.

[Brief explanation of the drawing]

, FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of the present invention.
FIG. 3 is a sectional view of the L panel 1, and is a waveform diagram for explaining the operation for color display.

Claims (1)

[Claims] A color display device that is entirely flat and includes an EL panel that changes color, and a liquid crystal panel that is overlapped with the EL panel and selectively forms a translucent area. .