JPS6033536A - Color liquid crystal display element - Google Patents

Abstract

PURPOSE:To display the other different color in a colored background with a guest-host type color liquid crystal display element by using a specific dichromatic dye as the dye having a liquid crystal compsn. CONSTITUTION:A dichromatic dye which has a bar-shape construction and has the characteristics of an L type dye molecule and a T type dye molecule (generates absorption A when the long axis direction of the dye molecule 3 and the electric field vector of light coincide and generates absorption B when the short axis direction and the electric field vector of light coincide) is used. More specifically, upper and lower electrode base plates subjected to an orientation treatment are placed to face each other in twisted disposition and a guest-host crystal compsn. consisting of, for example, a nematic liquid crystal ''ELI-1132'' with which a slight amt. of a cholesteric nanonate material is compounded and a dye ''LCD-108'' is sealed therebetween and polarizing plates are provided thereto to constitute a cell, by which the transmission type liquid crystal display element displayed by yellow in a blue background is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a color liquid crystal display element that responds to the application of an electric field and displays different colors.

<Prior Art> Conventionally, L-type dye molecules and T-type dye molecules are known as guest dye molecules in guest-host liquid crystal compositions.

As shown in FIG. 1, the L-type dye molecule 1 exhibits strong absorption when the long axis direction of the dye molecule and the electric field vector of light coincide.

For example, there are many pigments such as anthraquinone and azo. On the other hand, as shown in FIG. 2, the T-type dye molecule 2 exhibits strong absorption when the short axis direction of the dye molecule and the electric field vector of the light coincide. For example, there are dyes such as tetrazine.

These dyes absorb light only in a specific direction, so they are inserted into a liquid crystal cell as a guest host liquid crystal composition.
When the electric field is turned on and off, a colorless display is produced on a colored background or a colored display is produced on a colorless background, but there is a problem in that the brightness is affected by the colorless background or display.

<Objective> The present invention has been made in view of the above-mentioned conventional problems, and provides a color liquid crystal display element that exhibits different vivid colors regardless of whether or not an electric field is applied to the liquid crystal display cell. The purpose is to

<Example> In the case of a nematic type guest-host liquid crystal composition, a transparent electrode pattern and an alignment film were formed on soda-lime glass by the usual method, and then subjected to a rubbing treatment to form a twisted arrangement.
E Laminate the lower substrate, maintain the substrate spacing at approximately 10 pm, and insert a liquid crystal composition in which a trace amount of cholesteric nonanate substance and dye LCD108 (trade name) are blended into nematic liquid crystal ELI-1132 (trade name). Then, by attaching a polarizing plate to the outside of the substrate and irradiating it from behind the cell, a yellow display on a blue background is obtained. As another example, the present invention can also be applied to a phase change type guest-host smect type guest-host liquid crystal composition. The dichroic dye 3 used in these liquid crystal display cells produces absorption A when the long axis direction of the dye molecule matches the electric field vector of light, and the short axis direction and Absorption B occurs when the electric field vector of light coincides with the electric field vector of light. In this way, two-color formation is possible with one dye molecule.

<Effects> As explained above, according to the color liquid crystal display element of the present invention, two colors can be formed with one dye molecule, and the cost is lower than that of the conventional method of mixing L-type dye molecules and T-type dye molecules. It becomes cheaper. Further, the dye concentration may be low, and the influence on optical properties is small.

[Brief explanation of drawings]

FIG. 1 is an optical characteristic diagram of L-type dye molecules in a conventional guest-host liquid crystal composition, FIG. 2 is an optical characteristic diagram of T-type dye molecules, and FIG. 3 is a diagram of dichroic dye molecules according to the present invention. It is an optical characteristic diagram. 1: L-type dye molecule 2: T-type dye molecule 3: Dichroic dye molecule

Claims (1)

[Claims] 1. In a color liquid crystal display element in which a guest-host liquid crystal composition is inserted between at least two substrates and changes color depending on the application of an electric field, the dye molecules of the guest-host liquid crystal composition have a rod-like structure, and L A color liquid crystal display element characterized by being a dichroic dye having the characteristics of a type dye molecule and a T type dye molecule.