JPH04328520A - Liquid crystal nonglaring mirror - Google Patents

Abstract

PURPOSE:To obtain the bright nonglaring mirror which uses no polarizing plate by providing a liquid crystal cell wherein liquid crystal is dispersed and held in a matrix. CONSTITUTION:A liquid crystal cell 3 is provided on the front surface of a reflecting mirror 2 and held between transparent conductive sheets from before and behind. Namely, while no voltage is applied between the conductive sheets, a liquid crystal 5 is oriented along the wall of a capsule and incident light is scattered by the surface of the capsule and in the capsule, so the light transmissivity is small. In a voltage ON state, on the other hand, the long axis of the liquid crystal 5 is oriented at right angles to the conductive sheets and the incident light is not scattered, but travels straight, so that light transmissivity becomes maximum. Therefore, when the mirror is used in daytime when glaring prevention is not necessary, the voltage ON state is set between the conductive sheets and the incident light travels straight and is reflected by the reflecting mirror 2, thereby obtaining a glaring state wherein an image is bright. In nighttime when the glaring prevention is necessary, the voltage OFF state is set between the conductive sheets and the reflection factor of the reflecting mirror 2 decreases, thereby obtaining a nonglaring state wherein the image becomes dark.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to an anti-glare mirror using liquid crystal, and in particular, the present invention relates to an anti-glare mirror using liquid crystal, and in particular, the present invention relates to an anti-glare mirror using liquid crystal, and in particular, liquid crystal is dispersed and held in a polymer matrix to form liquid crystal microcapsules. (called liquid crystal)
This invention relates to an anti-glare mirror using.

0002

2. Description of the Related Art Some mirrors such as room mirrors, side mirrors, and door mirrors of vehicles such as automobiles are equipped with an anti-glare function to prevent dazzling caused by the headlights of a following vehicle.

0003

[Means for solving the problem] A specific means for anti-glare function is to have a mirror with two reflective surfaces with different reflectances, and use a high-reflective surface during the daytime when anti-glare is not required, and a mirror that has two reflective surfaces with different reflectances. There are mirrors that change the angle of the mirror to create a low-reflection surface at night (equipped on commercially available vehicles), and those that place a liquid crystal cell in front of the mirror and control the light transmittance of this liquid crystal cell. for adjusting the reflectance of
(Refer to Publication No. 8409).

0004

[Problem to be solved by the invention] Mirror angles that switch mirror angles have problems such as the image shifting when switching or double images depending on the surrounding brightness, and in recent years liquid crystal cells have been used. What is happening is attracting attention.

However, in the case of so-called liquid crystal anti-glare mirrors using liquid crystal cells, the overall image tends to become dark.

[0006]

[Means for Solving the Problems] In order to solve the above-mentioned conventional problems, the present invention provides a liquid crystal anti-glare mirror in which a liquid crystal cell is arranged in front of a reflecting mirror, in which the liquid crystal cell has liquid crystal dispersed in a matrix. It was kept.

[0007]

[Operation] Depending on the voltage applied to the liquid crystal cell, the transmittance of incident light, that is, the reflectance of the reflector on the rear surface of the liquid crystal cell changes, thereby providing an anti-glare state. Moreover, since no polarizing plate is used, the image does not become dark in the non-glare state.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the drawings, which show an example in which the invention is applied to a rearview mirror of a vehicle.

[0009] Reference numeral 1 is a concave case, and a reflector 2 is placed deep inside the case 1, and an NCAP is placed in front of the reflector 2.
A liquid crystal type liquid crystal cell 3 is arranged.

The liquid crystal cell 3 has a liquid crystal 5 dispersed in a matrix 4, which is covered with transparent conductive sheets 6, 7 from the front and back.
It is sandwiched between. Specifically, 1/4 part by weight of P-type nematic liquid crystal (Merck: ZL) was added to 25 wt% polyvinyl alcohol (PVA203, manufactured by Kuraray), which is a polymer having hydroxyl groups prepared as matrix 4.
I-2061) 5 is mixed into the matrix 4 together with tetraethoxysilane (not shown), which is a metal alkoxide prepared as a crosslinking agent, and stirred and emulsified with a homogenizer, and the obtained emulsion is placed on a film-like transparent conductive sheet 6. It was coated using a doctor blade to a dry film thickness of 15 μm, and then coated in an atmosphere of 50% RH and 25°C for 2 hours.
After drying for 4 hours and further drying at 60° C. for 1 hour, a transparent conductive sheet 7 similar to that described above is laminated on the dried coating film.

The liquid crystal cell 3 thus obtained has a matrix 4 in which a large number of encapsulated liquid crystals 5 with a diameter of 1 to 10 μm are scattered, and the matrix 4 contains silicon of tetraethoxysilane as a crosslinking agent. It works to crosslink polyvinyl alcohol.

When the voltage between the transparent conductive sheets 6 and 7 is off, the liquid crystal 5 is aligned along the wall of the capsule (see FIG. 3), and the difference in curvature at the interface between the matrix 4 and the liquid crystal 5 is Therefore, the light transmittance is low due to light scattering. In addition, when the voltage is on, the long axis of the liquid crystal 5 is aligned with the transparent conductive sheets 6 and 7.
If the curvature of the matrix 4 and the liquid crystal 5 are made equal, the light will travel straight without being scattered, and the light transmittance will be maximized.

Therefore, during the daytime when anti-glare is not required, the voltage is on between the transparent electrode sheets 6 and 7 of the liquid crystal cell 3, and the incident light goes straight without being scattered and is reflected by the reflecting mirror 2. Therefore, the image is bright and non-glare.

At night when anti-glare is required, the voltage between the transparent electrode sheets 6 and 7 of the liquid crystal cell 3 is turned off.
The incident light is oriented along the wall of the capsule of the liquid crystal 5, and cannot travel straight because it is scattered on the surface and inside of the capsule, and becomes cloudy and glass-like, reducing the light transmittance, that is, the reflectance of the reflecting mirror 2, and causing the image It becomes dim and becomes anti-glare.

[0015] The above-mentioned switching between the anti-glare and non-dazzle states can be performed by a manual switch operation by a vehicle occupant such as a driver;
Alternatively, automatic control using an optical sensor that detects the amount of external light may be used.

Furthermore, when a reverse mode liquid crystal 5 is used as the liquid crystal cell 3, the application of voltage to the transparent conductive sheets 6 and 7 of the liquid crystal cell 3 for switching between the anti-glare and non-glare states is performed in accordance with the above implementation. In contrast to the example, the voltage may be turned off in the non-dazzling state and the voltage turned on in the anti-glare state.

[0017]

Effects of the Invention The present invention provides a liquid crystal anti-glare mirror in which a liquid crystal cell is disposed in front of a reflecting mirror, in which the liquid crystal cell has liquid crystal dispersed and held in a matrix, which is different from the conventional liquid crystal anti-glare mirror. Compared to , it is brighter because it does not use a polarizing plate. Furthermore, NCAP liquid crystal has a wide viewing angle and uniform diffusivity, making it suitable for use as various vehicle mirrors. Furthermore, since the liquid crystal cell is used in the form of a sheet, it can be made lightweight and can be used on curved surfaces.

[Brief explanation of drawings]

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

FIG. 2 is a sectional view of a main part of the embodiment same as above.

FIG. 3 is a diagram showing the operation of the liquid crystal in the voltage-off state of the above embodiment.

FIG. 4 is a diagram showing the operation of the liquid crystal in the voltage-on state of the above embodiment.

[Explanation of symbols]

1 case 2 Reflector 3. Liquid crystal cell 4 Matrix 5 Liquid crystal 7, 8 Transparent conductive sheet

Claims (1)

[Claims] 1. A liquid crystal anti-glare mirror having a liquid crystal cell disposed in front of a reflecting mirror, wherein the liquid crystal cell has liquid crystal dispersed and held in a matrix.