JPS5991480A - Electrooptic display - 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 The present invention relates to an electro-optic display device having a novel configuration.

Among liquid crystal color display systems, a two-layer black shutter system using dichroic black dye has been proposed as a system that is superior in terms of visibility such as contrast and wide field of view. As shown in FIG. 1, this method has a structure in which two liquid crystal layers are superimposed, in which the liquid crystal molecules of the first liquid crystal layer and the liquid crystal molecules of the second liquid crystal layer 5 are aligned perpendicularly to each other. (In Figure 1, the liquid crystal molecules in the first liquid crystal layer 4 are oriented perpendicularly to the plane of the paper, and the liquid crystal molecules in the second liquid crystal layer 5 are oriented parallel to the plane of the paper.) Furthermore, both liquid crystals are dichroic. It uses NP material with black dye dissolved in it. When a color filter 6 and a light guide plate 7 are added to the rear surface of this liquid crystal display device and the illumination 8 is turned on, if no voltage is applied to the transparent electrode 3, the light from the illumination 8 is filtered through the color filter as shown in FIG. 1(a). However, due to the dichroic black dye in the first and second liquid crystal layers, visible wavelength light is absorbed and becomes colored light. The shimmering light is absorbed over the entire area, and the viewer cannot recognize the color of the shicolor filter due to this shutter effect. Furthermore, when a voltage is applied to the transparent electrode 3, the dichroic black dye is oriented perpendicularly to the substrate, as shown in Fig.
The second liquid crystal layer is in a transmitting state, and the colored light is not absorbed by each liquid crystal layer, allowing the viewer to recognize the color of the color filter.

When displaying on such a liquid crystal display device, the display state is that numbers, symbols, etc. of the color of the color filter are displayed on a black background.Although there is an advantage of being able to choose from a variety of hues using the color filter, it is difficult to display one display. On the other hand, one color is fixed and diversity cannot be obtained in one display.

On the other hand, in recent years, a color display element with a memory function, that is, an electrophoretic display device, has been proposed, in which charged pigment particles suspended in an opaque colored solvent are drawn onto a transparent electrode by an external electric field and adhered thereto. There is. This electrophoretic display device has the advantage of being able to display bright colors with high contrast and having memory characteristics. However, when displaying a 7-segment digital display, etc., the amount of current that flows during coloring differs depending on the area of the segment, resulting in differences in color shading between the segments, which is not suitable for practical use. It is.

The present invention has been made in view of these points, and it is an object of the present invention to provide an electro-optical display device that improves display diversity and has high visibility.

According to the present invention, a first liquid crystal layer, an intermediate transparent electrode substrate, and a second liquid crystal layer are sandwiched between a pair of transparent electrode substrates in the above order, and the liquid crystal molecules of the first liquid crystal layer and the second liquid crystal layer are sandwiched between a pair of transparent electrode substrates. In a liquid crystal display device in which liquid crystal molecules are oriented perpendicularly to each other and a dichroic black dye is dissolved in the liquid crystals of the first and second liquid crystal layers, an electrophotographic display is provided at the rear of the liquid crystal display device. An electro-optical display device characterized by the addition of the device is obtained.

The present invention will be explained using FIG. 2 of the embodiment. A in Figure 2
The part is a liquid crystal display part, and the configuration is the same as that in Fig. 1.
The structure is such that the color filter 6 and light guide plate 7 in FIG. 1 are replaced with the electrophoretic display device in section B. The liquid crystal display device is made by pasting together three rubbed transparent electrode substrates 1.1' and 1'' with an adhesive 2 containing glass fibers with a diameter of 10μ, and a liquid crystal RO-8A- in which a dichroic black dye is dissolved. Inject 653 (manufactured by Roche),
The injection hole is sealed. Furthermore, in the electrophoretic display section, a transparent electrode substrate 91 which also serves as a light guide plate and a back electrode substrate 92 are pasted together with a spacer IO interposed therebetween. The electrophoretic dispersion medium 14 in which Hansa Yellow particles B were suspended as a yellow pigment was injected, and the injection hole was sealed. .

When displaying in the electro-optic display device configured in this manner, when the electrophoretic display section B is in a coloring state, the yellow pigment B adheres to the transparent electrode 31 and the electrophoretic display surface is colored. The display will be yellow and yellow, or yellow on a black background. Electrophoresis (When the display part B is in a decolorized state, the yellow pigment B adheres to the back electrode 32, and the electrophoretic display surface becomes red of the solvent 14 and i+)
, you can get a red display on a black background. Therefore, by coloring and decoloring the electrophoretic, it is possible to clearly display two colors of yellow and red on a black background. Electrophoretic displays have memory characteristics, so if they are colored, they do not require electricity, retain their coloring, and are effective for long-term display; Display section A
Since this is performed using only electrophoretic display, differences in shading between segments cannot occur.

When the electro-optical device having the configuration shown in this embodiment is used as a display for a digital clock, for example, the time can be displayed in a novel manner such as yellow on a black background in the morning and red on a black background in the afternoon.

In the above embodiment, the electrophoretic display section was described as having a yellow-red color change, but the electrophoretic two-color change is not limited to yellow-red, and can be applied to all colors including white. It will be clear to those skilled in the art that two-color variations are possible, and even intermediate colors are possible.

In the embodiment, one electrophoretic transparent electrode is used, but it is possible to divide it into a plurality of electrodes.

As described above, according to the present invention, it is possible to provide an electro-optical display device with improved display diversity and high visibility.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a liquid crystal display device with a two-layer black shutter type.
) indicates the display status. FIG. 2 shows a cross-sectional view of an electro-optic display device according to an embodiment of the invention. A...Liquid crystal display section, B...Electrophoretic display section, 1.1', 11...Transparent electrode substrate, 2,2'...・Adhesive material, 3.31・
...Transparent electrode, 32...Back electrode, 4.
...First liquid crystal layer, 5... Second liquid crystal layer, 6
...Color filter, 7...Light guide plate,
8...Lighting, 9...Transparent electrode substrate, 1
0...Spacer, 13...Yellow pigment,
14... Red solvent. Z l diagram

Claims (1)

[Claims] A first liquid crystal layer, an intermediate transparent electrode substrate, and a second liquid crystal layer are sandwiched between a pair of transparent electrode substrates in the above order, and liquid crystal molecules in the first liquid crystal layer and liquid crystal molecules in the second liquid crystal layer are sandwiched between the pair of transparent electrode substrates. In a liquid crystal display device in which the liquid crystals are oriented perpendicularly to each other and a dichroic black dye is dissolved in the liquid crystals of the first and second liquid crystal layers, an electrophoretic display device is provided behind the liquid crystal display device. An electro-optical display device characterized by adding: