JPH04143733A - Photoconduction type liquid crystal light valve - Google Patents

Abstract

PURPOSE:To joining transparent substrates across a uniform gap and to obtain a projection image with superior resolution by making the coefficient of thermal expansion of the transparent substrate which seals a write side smaller than that of the transparent substrate which seals a read side. CONSTITUTION:The 1st transparent substrate A which is arranged on the write side and the 2nd transparent substrate B which is arranged on the read side are sealed with thermosetting resin 22 at high temperature with liquid crystal orienting films 4 and 3 in while the proper gap is held by spacers 2. The coefficient alphaB of thermal expansion of the substrate B is larger than the coefficient alphaA of the substrate A, so the substrate B absorbs the curvature of the substrate A which is generated at the time of the filming of a-Si in addition to the thermal expansion of the substrate A which is caused at the time of heating and the thermosetting resin 22 is solidified in this state, so that while the substrates A and B are united after being cooled, the external abutting surface of a fiber plate 11 is corrected into a plane. Consequently, the photoconduction type liquid crystal light valve which forms a projection image with superior resolution while the gap is uniformed is obtained.

Description

TECHNICAL FIELD The present invention relates to a photoconductive liquid crystal light valve used in a projection type liquid crystal display device.

Background Art FIG. 1 is a block diagram showing an example of a photoconductive liquid crystal light valve. In the figure, a spacer 2 is placed around a liquid crystal layer 1.
are provided, and liquid crystal alignment films 3 and 4 are arranged on both sides of the liquid crystal layer 1. The liquid crystal layer 1 and the photoconductive film 5 are a light reflecting film (
They are stacked with a dielectric mirror (dielectric mirror) 6 and a light absorption film (light blocking film) 7 sandwiched therebetween. The light reflection film 6 is for reflecting the readout light incident from the readout side, and the light absorption film 7 is for reflecting the readout light incident from the readout side.
This is to absorb light leaking from the A transparent conductive film 8 as a transparent electrode is provided on the outside of the liquid crystal layer 1 and the photoconductive film 5.
9 are arranged, and all of these are sealed with a glass substrate 10 and a fiber plate 11. An alternating current voltage is applied between the transparent conductive films 8 and 9 by a drive power source 12.

This photoconductive liquid crystal light valve (hereinafter referred to as LCLV)
FIG. 2 shows an example of the configuration of a projection type display using, for example, an incident image from a CRT as the writing light. In the figure, the writing side fiber plate 11 of the LCLV 13 shown in FIG. 1 is joined to the face plate of the CRT 14. The face plate joint surface of the CRT 14 is also composed of a fiber plate 15, and the LCLV 1 is connected to the LCLV 1 through a gap filled with a refractive index matching liquid 16.
It is bonded to the fiber plate 11 of No. 3.

An incident image as a writing light incident from the CRT 14 does not pass through the imaging optical system inside the LCLV 13, and causes an orientation change of the liquid crystal layer 1 according to the incident image and the amount of light.

On the other hand, on the readout side of the LCLV 13, an optical system for projecting onto the screen 17 is configured, and the readout light emitted from the light source 18 is reflected by a polarizing prism 20 via a lens 19 and enters the readout side of the LCLV13. be done. Then, the orientation change of the liquid crystal layer 1, that is, CR
The readout light is reflected with a brightness that corresponds to the incident image from T14. This reflected readout light is projected onto the screen 17 via the lens 21 after passing through the polarizing prism 20 as projected output light.

By the way, conventionally the fiber plate 1 of LCLV13
In some cases, the contact surface with the fiber plate 15 of the fiber plate 1 was not flat and curved. In this case, fiber plate 1
The gap forming the refractive index matching layer between the fiber plate 1 and the fiber plate 15 becomes non-uniform.

This non-uniformity of the gap appears in the projected image as uneven resolution, so the adhesion between the two is extremely important. In order to improve the resolution, it is desirable that the gap between the two be narrow and uniform.

According to the purpose of the invention, the present invention was made to eliminate the above problems, and the purpose is to
By providing a photoconductive liquid crystal light valve which has a uniform gap between the face plate of a writing light source such as the above and the writing side face plate of the photoconductive liquid crystal light valve and has excellent resolution of a projected image. be.

Structure of the Invention The photoconductive liquid crystal light valve according to the present invention includes a pair of transparent electrodes disposed outside the laminated photoconductive layer and liquid crystal layer,
A photoconductive liquid crystal light valve configured to be sealed by a first transparent substrate disposed on the write side and a second transparent substrate disposed on the read side, the first transparent substrate being sealed with the first transparent substrate disposed on the read side. It is characterized by having a smaller coefficient of thermal expansion than the transparent substrate No. 2.

Effect of the Invention In the photoconductive liquid crystal light valve according to the present invention, due to the difference in coefficient of thermal expansion between the read-side sealing substrate and the write-side sealing substrate, the curvature of the write-side face plate occurs when forming the liquid crystal cell gap. be corrected.

EXAMPLE This example will be explained with reference to FIG. 3 along with an example of a method for manufacturing a photoconductive liquid crystal light valve.

A fiber plate 11 serves as a sealing substrate on the writing side of the LCLV 13, and has a coefficient of thermal expansion αA. On this surface, a transparent conductive film 9, for example, an amorphous Q
a photoconductive film 5 made of silicon (hereinafter referred to as a-5i);
A light absorption film 7 and a light reflection film 6 are sequentially formed. moreover,
A liquid crystal alignment film is formed on this light reflection film using an alignment agent or alignment property suitable for the substrate and liquid crystal. thus,
A writing side substrate A in the liquid crystal cell gap is configured. Here, due to compressive stress when the photoconductive film 5 is formed, the fiber plate 11 is warped so that the photoconductive film 5 is placed on the outside.

On the other hand, the glass substrate 10 serving as the sealing substrate on the reading side of the LCLV 13 has a coefficient of thermal expansion αB, and the coefficient of thermal expansion αA of the fiber plate 11 in the substrate A on the writing side
means that the relationship αA x αB holds true. A transparent conductive film 8 is formed on this surface, and
Similar to the writing side, the substrate B on the reading side in the liquid crystal cell gap is formed with an alignment-treated liquid crystal alignment film 3.
is configured.

Next, the substrate A and the substrate B are bonded with a thermosetting adhesive or a sealant called ffI2 while maintaining an appropriate distance between them with the liquid crystal alignment films 3 and 4 inside.
2 at high temperature, for example below 150 degrees Celsius.

Since the thermal expansion coefficient αB of the substrate B is larger than the thermal expansion coefficient αA of the substrate A, in addition to the thermal expansion of the substrate A that occurs during this heating, there is also the thermal expansion coefficient αB that occurs when forming the a-Si film. The substrate B absorbs the warpage of the substrate A, and in this state, the thermosetting resin 22 solidifies, so that after cooling, the substrate A and the substrate B remain integrated and contact the external contact surface of the fiber plate 11. In other words, the face plate is C in the same figure.
It is corrected to a flat surface as shown below.

In the liquid crystal cell gap C thus produced, liquid crystal is then injected into the empty cell surrounded by the spacer 2 and the liquid crystal alignment films 3 and 4, thereby completing one LCLV.

In this example, the thermal expansion coefficients of substrates A and B are simply expressed as variables αA and αB, but these variables αA
The specific values of αB and αB can be determined by a simulation executed by a computer based on parameters such as the material and thickness of each layer of the LCLV.

As described in detail, in the photoconductive liquid crystal light valve of the present invention, the coefficient of thermal expansion of the transparent substrate sealing the write side is smaller than that of the transparent substrate sealing the read side.
The curvature of the external contact surface of the write-side sealing substrate is corrected to a flat surface. Therefore, the write-side sealing substrate and the face plate of a write light source such as a CRT are joined with a uniform gap, and a projected image with excellent resolution can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a configuration example of a photoconductive liquid crystal light valve, FIG. 2 is a block diagram showing an example of a projection type liquid crystal display, and FIG. 3 is a fabrication of a photoconductive liquid crystal light valve in an embodiment of the present invention. FIG. Explanation of symbols of main parts 1...Liquid crystal layer 5...Photoconductive film 8.9...Transparent conductive film 10...Glass substrate 11...Fiber plate 22...Thermosetting resin plate

Claims (3)

[Claims] (1) A pair of transparent electrodes are arranged on the outside of the laminated photoconductive layer and liquid crystal layer, and sealed by a first transparent substrate arranged on the writing side and a second transparent substrate arranged on the reading side. A photoconductive liquid crystal light valve having a configuration in which the first
A photoconductive liquid crystal light valve, wherein the transparent substrate has a coefficient of thermal expansion smaller than that of the second transparent substrate. (2) The photoconductive liquid crystal light valve according to claim 1, wherein the first transparent substrate contains less alkali component than the second transparent substrate. (3) The photoconductive liquid crystal light valve according to claim 1, wherein the first transparent substrate and the second transparent substrate are sealed with a thermosetting resin.