JPS6141123A - Glare proof mirror of liquid crystal type - Google Patents

Abstract

PURPOSE:To prevent the occurrence of an interference pattern by setting the orientation processing of a transparent electrode substrate and a reflecting electrode substrate to the surface treatment for the homogeneous array, making its rubbing direction to non-parallel and setting a helix angle of a liquid crystal to approximately 360 deg.. CONSTITUTION:A transparent electrode 2 is formed on the front surface of a substrate 1 made of soda glass, etc., and an organic or inorganic oriented film 3 where liquid crystal molecules are homogeneously arrayed is formed thereon. Moreover, a rear surface substrate 7 is made of soda glass, etc., and a reflecting electrode 6 such as an aluminum electrode is formed thereon. On its electrode 6 an oriented film 5 is formed. The rubbing processing is applied in a specific direction to respective electrode substrates 2 and 6. Then each rubbing direction of the substrate is set to the non-parallel direction under such condition where the substrates 2 and 6 up and down are stuck together.

Description

[Detailed Description of the Invention] Technical Field> The present invention relates to an anti-glare mirror using liquid crystal (liquid crystal type anti-glare mirror) used in rear-view mirrors, etc. of vehicles such as automobiles, and in particular, This invention relates to an improvement in a liquid crystal type anti-glare mirror having a guest-host liquid crystal between a transparent electrode substrate and a reflective electrode substrate.

Prior Art> Liquid crystal type anti-glare mirrors using guest-host liquid crystals have been proposed in the past, but the conventional anti-glare mirrors using guest-host liquid crystals have the problem of generating interference patterns. This interference pattern is not very visible under a light source with a wide wavelength range such as sunlight, but it can be seen in sodium lamps in tunnels and on highways, mercury lamps on highways, and even halogen lamps in cars. It appears conspicuously under a monochromatic light source.

<Object of the Invention> The present invention aims to provide a liquid crystal type anti-glare mirror structure that can solve the above problems, and specifies the rubbing direction of two electrode substrates and the twist angle of the liquid crystal. Particularly, it is an object of the present invention to provide a liquid crystal type anti-glare mirror configured to reduce or prevent the occurrence of the interference pattern when viewed from a specific direction.

<Structure of the Invention> The liquid crystal type anti-glare mirror of the present invention has a guest-host liquid crystal between a transparent electrode substrate and a reflective electrode substrate, and the alignment treatment of both substrates is performed to form a homogeneous alignment. surface treatment, and the rubbing direction is antiparallel.
It is characterized in that the twist angle of the liquid crystal is 360° or approximately 360°.

<Example> FIG. 1 is a sectional view showing the structure of an anti-glare mirror using a phase change type guest-host liquid crystal.

1i front substrate, made of soda glass or borosilicate glass, plastic film, or the like. A transparent electrode 2 is formed on the front substrate l. moreover,
An organic or inorganic alignment film 3 is formed on the transparent electrode 2 to homogeneously align all liquid crystal molecules. On the other hand, 7 is a rear substrate made of soda glass, borosilicate glass, or the like.

Bon, back Mika &, 7J:, ni, u 734! M
El-M: formed on the electrode 6, and furthermore, the same alignment film 5 as described above is formed thereon. Each electrode substrate is subjected to rubbing treatment in a specific direction. 4I/'i is a phase change type guest-host liquid crystal sandwiched between the transparent electrode substrate and the reflective electrode substrate.

When the upper and lower substrates are bonded together, the total angle formed by the rubbing directions of the upper and lower substrates is θ, and the twist angle of the liquid crystal of the phase change guest-host liquid crystal having a Grandshuan structure between the upper and lower substrates is φ ( Figure 2) 0 The table below shows the results of observing the strength anisotropy of the interference pattern and the degree of the interference pattern by changing θ and φ.

This result shows that, at the level of the interference pattern observed under a sodium lamp, when p = 860'', the occurrence of the interference pattern in a specific direction is alleviated. It is sufficient to match the visual direction of the hand.However, when θ = 0°, -360°, turn off the power at "7".
It is not suitable because it sometimes becomes cloudy. Therefore, θ is '
18G', that is, the rubbing direction must be antiparallel.

The above specific direction will be explained with reference to FIG. 3. Is the above guest-host liquid crystal nematic? Il, a mixture of chiral nematic liquid crystal or cholesteric liquid crystal and a dye, but if the chiral nematic liquid crystal or cholesteric liquid crystal is dextrorotatory (for example, cholesteric chloride), the above-mentioned specific direction, that is, the direction in which the interference pattern becomes invisible (indicated by a thick arrow in the figure) is the rubbing direction (indicated by a thin arrow in the figure)
The direction perpendicular to θ is defined as θ°, and the angle ψ is defined as the clockwise direction being positive, and ψ is in the range of +10° to +50°. On the other hand, in the case of levorotation (for example, cholesteric nonanate) //'i, ψ knee is in the range of 20° to +20°.

<Effects of the Invention> As explained above, according to the present invention, the occurrence of interference patterns, which is a problem in conventional liquid crystal anti-glare mirrors, can be substantially alleviated or prevented, which is extremely useful. This makes it possible to provide a liquid crystal type anti-glare mirror.

[Brief explanation of drawings]

FIG. 1 is a sectional view, and FIGS. 2 and 3 are perspective views. Explanation of symbols 1: Front substrate, 2: Transparent electrode, 3: Alignment film, 4 Nigest host liquid crystal, 5: Alignment film, 6: Reflective electrode, 7': Back substrate.

Claims (1)

[Claims] 1. In a liquid crystal anti-glare mirror having a guest-host liquid crystal between a transparent electrode substrate and a reflective electrode substrate, the alignment treatment of both substrates includes surface treatment for homogeneous alignment. A liquid crystal type anti-glare mirror characterized in that the rubbing direction is antiparallel and the twist angle of the liquid crystal is 360° or approximately 360°.