JPS6059323A - Liquid crystal cell - Google Patents

Abstract

PURPOSE:To reduce the manday of vapor deposition, to hold light reflectivity high and constant, and to improve manufacture yield by allowing one liquid crystal oriented film to serve as a light reflecting film. CONSTITUTION:A transparent electrode 2 of ITO, light absorbing film 3 of CdTe, and liquid crystal oriented film 15 of Al as the reflecting film are laminated successively on the internal surface of a glass substrate 1 on a laser light irradiation side. A transparent electrode 8 of ITO and a liquid crystal oriented film 7 of SiO are formed successively on the internal surface of a glass substrate on a projection light side. The substrates 1 and 9 are provided with liquid crystal 6 across spacers 10 and 11. The Al film 15 as a reflecting and liquid crystal oriented film is formed on the film 3 in gaseous argon by performing vapor deposition at, for example, 85 deg. to the vertical direction of the substrate, and about 90% high reflectivity to projection light is obtained by measurement.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal cell used as a display device for wristwatches, electronic computers, large-screen displays for aircraft control systems, and the like.

9. There are two types of liquid crystal cells: direct view type and projection type. Projection liquid crystal cells are widely known as light valves in large screen displays for air traffic control and the like. Addressing methods for liquid crystal cells include laser thermal addressing, optical addressing, CCD addressing, etc., but here, in order to make the explanation more concrete, a laser thermal addressing liquid crystal cell will be explained.

When a liquid crystal is heated to make the orientation of the liquid crystal molecules irregular and then rapidly cooled, the irregular orientation of the heptalytic molecules is maintained and a phenomenon of light scattering occurs. This is called the thermo-optic effect of liquid crystal. In a liquid crystal cell that utilizes this effect,
A liquid crystal cell is irradiated with a laser beam to cause a temperature rise in the irradiated area to write an image, and to erase the written image, an electric field is applied to the liquid crystal to forcibly align the liquid crystal molecules.

When the alignment of the liquid crystal molecules is good, the liquid crystal becomes transparent over the entire surface, and when the alignment is poor, the liquid crystal becomes cloudy partially or over the entire surface.

In a liquid crystal cell, an image is written by irradiating a transparent liquid crystal with a laser beam to turn it into a cloudy state, that is, a light scattering state, but if the alignment state is poor, the image cannot be written.

FIG. 1 is a sectional view of a conventional projection type liquid crystal cell. On the inner surface of the laser beam irradiation side substrate 1, a transparent electrode 2, a light absorption film 3,
A light reflection film 4 and a liquid crystal alignment film 5 are formed in sequence. The written image is projected onto a reading screen by projection light, or a transparent electrode 8 and a liquid crystal alignment film 7 are then formed on the inner surface of the substrate 9 on the projection source side. These two substrates 1 and 9 are held at a constant distance through spacers 10 and 11, and their sides are sealed with adhesives 12 and 13.

Then, liquid crystal 6 is injected into a gap of 90 mm between both substrates J.

In such a projection type liquid crystal cell, the liquid crystal alignment film 5 is
As means for this, there are rubbing of the light reflection film 4 and oblique vapor deposition of SiO on the light reflection film 4. However, the rubbing method requires a complicated manufacturing process and requires more experience, and the rubbing method cannot be used when the light reflecting film is soft such as an L film or an Au film. The SiO obliquely deposited film can be formed into a uniform film depending on the gas release during evaporation.
It is difficult to control the film thickness, and the light reflectance changes as the film thickness changes. Therefore, the manufacturing yield of liquid crystal cells was low. Furthermore, the oblique evaporation method requires a lot of man-hours because it uses a x15 empty process, but providing more laser light irradiation (liquid crystal orientation in the fill) may complicate the manufacturing process of the liquid crystal cell.ノζ.

The purpose of the present invention is to improve the manufacturing process. The purpose of the present invention is to provide a liquid crystal cell that is simple and has the highest manufacturing efficiency.

The structure of the present invention is characterized in that, in a liquid crystal cell in which a liquid crystal is placed between two substantially flat liquid crystal alignment plates, one of the liquid crystal alignment plates also serves as a light reflecting plate.

The present invention will be described in detail below with reference to the drawings.

FIG. 2 is a sectional view of a projection type liquid crystal cell according to an embodiment of Mizumotori. I' is on the inner surface of the glass substrate 1 on the laser beam irradiation side.
Transparent electrode 2 of l”0, light absorption of CdTe ■Kan 3, A
, 1 reflective film/liquid crystal aligning film 15 are sequentially formed.

On the other hand, the inner surface of the glass substrate 9 on the projection source side has I'lI"0
The transparent electrode'k8% S+O liquid crystal liquid crystal alignment novo 7 was sequentially formed. These two glass substrates 1 and 9 are held at a constant distance through spacers 1, 0 and 11, and their peripheries are sealed with adhesives 12 and 13. And both substrates 1,
Normal octyl ano-biphenyl liquid crystal 6 is injected into the 90-gap gap.

An L film 15 that serves both reflection and liquid crystal alignment is created by diagonally evaporating the CdTe light absorption film 3 on the CdTe light absorption film 3 in the vertical direction of the substrate at an angle of 85° in argon gas, and increases the reflectance of the projected light. As a result of measurement, 9 for all manufactured examples.
The reflectance was as high as 0.0, which was comparable to the reflectance obtained with the conventional structure shown in FIG. The variation in reflectance caused by the variation in film thickness of the conventional product alignment film 5 is also eliminated by using the AA film as the reflective film and liquid crystal alignment film 15. A7 made in argon gas
The film 15 showed a very clean surface condition, and the liquid crystal molecules showed good alignment in all the fabricated examples. The incident angle of Al atoms with respect to the substrate 1 in the reflective film/liquid crystal alignment film 15 may be other than 85°. angle of incidence is 6
Even in the range of 0° to 89°, all the films 15 produced in argon gas exhibited a high reflectance of about 90%, and the liquid crystal molecules also showed a good alignment state.

FIGS. 3A to 3C are partial cross-sectional views of this embodiment showing the alignment state of liquid crystal molecules. In the figure, numeral 61 indicates a liquid crystal region with good molecular orientation, that is, a transparent state, and 62 indicates a liquid crystal region with poor molecular orientation, that is, a cloudy state. FIG. 3(a) shows a liquid crystal cell in which the incident angle of Al atoms is 70° with respect to the vertical direction of the substrate 1. Since the alignment state of the liquid crystal molecules is good, the entire liquid crystal 6 is in a transparent liquid crystal region 61. On the other hand, FIG. 3(b) shows a liquid crystal cell in which the incident angle of Al atoms is 50° with respect to the vertical direction of the substrate 1. A region with defective molecular orientation occurred in a part of the liquid crystal 6, resulting in a cloudy liquid crystal region 62. Further, FIG. 3(C) shows a liquid crystal cell in which the incident angle of Al atoms is 30° with respect to the vertical direction of the substrate 1. At this time, a defective orientation of molecules occurred throughout the liquid crystal 6, resulting in a liquid crystal region 62 in a cloudy state over the entire area.

In addition, in an example in which an Au film is used as the light reflection film/liquid crystal alignment film 57, the incident angle of Au atoms to the substrate 1 is 6
Even in the range of 0° to 89°, the reflectance for the projected light is on the same level as the reflectance obtained with the conventional structure. There is no longer a change in the rate. Furthermore, the liquid crystal molecules showed good alignment in all of the manufactured examples.

In this way, since the liquid crystal cell of the embodiment shown in FIG. 2 has a structure that serves as both a light reflection film and a liquid crystal alignment film, the number of film deposition steps is reduced by one compared to the conventional one shown in FIG. is simple, and the light reflectance is high and constant, so the manufacturing yield is high.

Note that although the above-mentioned embodiment was a projection type liquid crystal cell, the present invention can also be applied to a direct view type liquid crystal cell.

As described above, according to the present invention, a liquid crystal cell with a simple manufacturing process and a high manufacturing yield can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional liquid crystal cell, Fig. 2 is a cross-sectional view of an embodiment of the present invention, and Fig. 3 (a), (b), and (C).
is a partial cross-sectional view of this example showing the alignment state of liquid crystal molecules. 1.9...Substrate, 2,8...Transparent electrical contact, 3...Light absorption film, 4...Light reflection film,
5, 7...Liquid crystal alignment), 6...Liquid crystal, 10.11...Spacer, 12゜13...
... Adhesive, 15 ... Ad light reflection film and liquid crystal alignment film, 61 ... Liquid crystal region in transparent state, 62 ...
...Cloudy liquid crystal area.

Claims (1)

[Claims] (1) A liquid crystal cell in which a liquid crystal is sandwiched between two substantially parallel liquid crystal alignment films, in which one of the liquid crystal alignment films also serves as a light reflecting film. The liquid crystal cell according to claim 1, wherein the liquid crystal cell is an Al film or an Au film.