JPS594690B2 - reflective liquid crystal cell - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reflective liquid crystal cell, and particularly to a reflective liquid crystal cell using crystallized glass for one of the insulating substrates.

Conventionally, a proposal has been made to use white crystallized glass for one of the substrates in a reflective color liquid crystal cell to eliminate the disadvantage that the display pattern is reflected on the back side of the substrate and the image appears double.

However, in practice, when transparent electrodes are formed on crystallized glass by vapor deposition or the like, a serious problem arises in that the resistance value of the transparent electrodes increases. The inventors conducted various studies on increasing the resistance value in transparent electrodes, and found that crystallized glass is a uniform microcrystalline aggregate that reflects light well, but unlike ordinary glass substrates, it contains components such as sodium and potassium. It was found that the physical properties of the transparent electrode change because these components easily seep out onto the surface and diffuse into the transparent electrode.

The present invention forms a diffusion prevention layer made of silicon oxide, indium oxide, and aluminum oxide between an insulating substrate made of crystallized glass and a transparent electrode to prevent components in the crystallized glass from diffusing into the transparent electrode. It is characterized by what it did.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram for explaining an embodiment of the present invention.
Crystallized glass is immersed in an acetate solution containing organic silicon (vinylsilane) as the main component, taken out and
An insulating substrate made of crystallized glass on which a silicon dioxide film 6 is formed on one side by firing at 00°C for 30 minutes, and a mixed oxide film 7 of silicon dioxide, indium oxide, and aluminum oxide is further provided thereon by a method described later. Make 4.

Transparent electrodes 2 are provided on the surfaces of this insulating substrate 4 and the insulating substrate 1 made of soda glass by vapor deposition or sputtering, and an insulating coating 3 is further formed on the surfaces thereof. These two insulating substrates 1 and 4 are treated with a silane coupling agent DMOAP, which is a vertical alignment agent, to form a vertical compound film 5, and then bonded together with an epoxy adhesive to form a liquid crystal cell. This cell is filled with nematic liquid crystal to which 0.7% of chiral nematic liquid crystal and 1% of dichroic dye are added. When no voltage is applied, the liquid crystal and dye are perpendicular to the substrate and appear white, and when voltage is applied, the display pattern becomes blue, so the display pattern does not appear double to the viewer, making it a positive display guest host type with good visibility. A liquid crystal cell is created. The mixed oxide film 7 is formed by dissolving a mixture of an organosilicon compound, an organoindium compound, and an organoaluminum compound in an organic solvent and further adding a viscosity agent to the resulting paste, which is then applied onto the silicon dioxide film 6 by screen printing. It is formed by heating and firing.

Examples of organic silicon compounds that can be applied to this include vinylsilane, organic indium compounds such as indium alkoxide, indium acetylacetonate, etc.
Organoaluminum compounds include aluminum alkoxide, aluminum acetylacetonate, etc.
Any material may be used as long as it is stably dissolved in a high boiling point organic solvent and completely becomes an oxide when fired at 450 to 700°C. next,
The organic solvent required for paste formation is one that has poor reactivity with organosilicon compounds, organoindium compounds, and organoaluminum compounds, and has a boiling point of 180 to 350°C, such as benzylalcono V1 dipropylene. High boiling point organic solvents such as high boiling point alcohols such as glycol, high boiling point esters such as benzyl acetate and carbitol acetate, and high boiling point ethers such as butyl cellosolve can be used. The viscosity agent must have good solubility in the organic solvent and be completely thermally decomposed by firing at 450 to 700°C, and cellulose-based viscosity agents such as ethylcellulose and nitrocellulose can be used. . An example of the composition of the paste and the firing conditions are as follows.

Indium acetylacetonate 27 Aluminum acetylacetonate 17 Vinylsilane
2y benzyl acetate ribenzyl alcohol 70yel = 7:3 mixed solvent ethinoresenolose firing conditions 550°C 8,57 20 minutes Figure 2 shows a transparent electrode formed directly on an insulating substrate made of crystallized glass ( Curve A), one in which a SiO2 film is provided between the crystallized glass insulating substrate and the transparent electrode (curve B),
A diffusion prevention layer made of a mixed layer of SiO2In2O3-Al2O3 was provided between the crystallized glass insulating substrate and the transparent electrode described in the example of the present invention (curve C).
It is a figure which shows the result of examining the resistance value change rate of a transparent electrode by subjecting to a 0 degreeC heat resistance test.

As is clear from this figure, compared to the conventional one (curve A), the one according to the present invention (curve C) has less deterioration of the transparent electrode and has a stable resistance value.

Films made of silicon dioxide, indium oxide, and aluminum oxide each have the following problems.

That is, a film containing silicon dioxide or aluminum oxide as a component has an excellent effect of preventing the diffusion of crystallized glass components, but the adhesion to the glass substrate is insufficient and the diffusion preventing effect cannot be maintained for a long period of time. A film containing indium oxide as a component has good film formability and adhesion to a glass substrate, but has an insufficient effect of preventing diffusion of crystallized glass components. However, a diffusion prevention layer made of a mixed oxide of silicon dioxide, indium oxide, and aluminum oxide has a good effect of preventing diffusion of crystallized glass components, has excellent film formability and film strength, and can maintain the diffusion prevention effect for a long period of time.

The present invention is configured as described above, and can provide a liquid crystal cell with stable characteristics.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of a liquid crystal cell according to an embodiment of the present invention;
FIG. 2 is a thermal test characteristic diagram. 2... Transparent electrode, 4... Crystallized glass insulating substrate, 6... Silicon dioxide film, 7...
...SiO2-InO2-Al2O3 mixed film.

Claims (1)

[Claims] 1. In a structure in which a transparent electrode, an insulating film, and an alignment film are sequentially formed on an insulating substrate made of crystallized glass, there is a gap between the insulating substrate and the transparent electrode to prevent components in the crystallized glass from diffusing into the transparent electrode. A reflective liquid crystal cell characterized in that it is provided with an anti-diffusion layer made of a mixed oxide of silicon oxide, indium oxide and aluminum oxide to prevent diffusion.