JPH0313915A - Production of electro-optical element of active matrix type - Google Patents

Abstract

PURPOSE:To prevent a switching element from being broken upon lapse of time at the time of driving by providing a stage for heating substrates in a vacuum just before sealing of a liquid crystal therebetween. CONSTITUTION:The substrates stuck to each other are put into a vacuum dryer and while the inside of the dryer is evacuated to a vacuum, the substrates are heated for 45 minutes at 125 deg.C. The vacuum degree of this time is from 1Torr to about 1X10<-3>Torr. The active matrix type electrooptical element produced by adding such stage to the conventional process for production has extremely high reliability. The reason thereof lies in that the moisture in the panel can be mostly removed by heating the substrates in the vacuum. The breaking of the switching element with lapse of time at the time of the driving which is heretofore of problem is prevented in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of manufacturing an active matrix electro-optical element using a switching element used in large-scale computer displays, optical shutters, and the like.

[Summary of the invention]

The present invention is a method for manufacturing an active matrix electro-optical element, in which a step of heating the substrate in a vacuum immediately before placing a liquid crystal between the substrates prevents the destruction of a plurality of switching elements over time. be.

[Conventional technology]

In recent years, the active matrix iron optical elements that have been used in color LCD TVs and laptop-knob computers have made it possible to increase the optical density by forming a switching element in each pixel on the substrate surface, resulting in high-speed response and
Future developments are expected as it has features such as high contrast.

Active matrix electro-optical elements are MIM (gate
tal-1nsulator-Metal) and MS
Two-terminal type such as l (Metal-5emi-Insulator) and TPT (Thin-Film-T
It is roughly divided into three terminal type (transistor). The structure of an MSI panel, which is a typical two-terminal active matrix electro-optical element, will be explained using FIG. Figure 3 (support) is a plan view of the MIS panel pixel section, D is M
FIG. 3 is a cross-sectional view of a pixel section of an SI panel. In FIG. 3, IB, 1 is an upper substrate, 2 is a column electrode, 3 is a lower substrate, 4 is a row electrode, 5 is a pixel electrode, 6 is a nonlinear resistive film layer, and 7 is an alignment film. The switching element has a structure in which a nonlinear resistance layer 6 is sandwiched between a row electrode 4 and a pixel electrode 5. Upper board 1
and the lower group 41i3 are changed from 5 to 1 by adhesive and spacer particles.
They are bonded facing each other with a spacing of 0 microns, and a liquid crystal is sealed between them. The switching element is OFF when a low voltage is printed on both ends of the nonlinear resistive film layer 6.
However, when the applied voltage exceeds a certain value, the switching element turns on and voltage is applied to the liquid crystal.

Next, an outline of the conventional manufacturing method of the active matrix type electro-optical element shown in FIG. 3 will be described below in accordance with the flowchart shown in FIG.

fal An ITO layer is formed on a glass substrate that will become the lower substrate 2 by sputtering or coating (19), and then patterned to form a pixel electrode 5.

ib) A layer of metal such as Cr, which will become the nonlinear resistance film layer 6 and the row electrodes 4, is formed thereon and patterned to form a switching element as shown in FIG. 3.

fel On the other glass substrate that will become upper substrate 1 ■
Column electrodes 2 are formed by forming and patterning a TO film.

fdl Perform alignment treatment on both glass substrates.

fal Apply adhesive to the lower substrate Fi2, sprinkle spacer particles on the upper substrate and attach both convex temporary parts.

ffl　Liquid crystal is sealed in the gap between panels.

(gl Connect with the drive circuit.

(Al and fb+ are manufacturing processes for a special substrate having a switching element (C1 to (fl) are basically the same as the manufacturing process for normal electro-optical elements.

(Problem to be Solved by the Invention) However, the active matrix type electro-optical element manufactured by the above manufacturing method has a drawback that the switching element breaks down over time when driven. This is thought to be due to an electrochemical reaction between Cr in row a and moisture adsorbed within the panel as shown in the following equation.

(2Cr + 7 HlO”HlCrlOl + 6
Hz> FIG. 4 shows a plan view of the pixel portion where Cr, which is the row electrode, is dissolved and destroyed by this electrochemical reaction. In FIG. 4, 4 is the row electrode and 6 is the pixel electrode.

As shown in the figure, a destroyed switching element no longer operates normally, and even if a voltage that turns it on is applied, the pixel remains OFF.
It ends up being the turn in the FF state.

Means for Solving Problem C] In order to solve the above-mentioned problems, the present invention provides a step in the manufacturing process of an active matrix electro-optical element, in which W temporary is heated in a vacuum immediately before filling liquid crystal between the substrates. has been established.

[Effect]

As explained in the problem section, an electrochemical reaction occurs between the Cr row electrode and the moisture adsorbed between the substrate during the manufacturing process, causing the row electrode part of the switching element in Figure 3 to become as shown in Figure 4. This causes the wire to melt and become disconnected, causing the switching element to no longer operate normally. Therefore, by providing a step in which the substrates are heated in a vacuum between the process of bonding the substrates and the process of sealing the liquid crystal, this prevents damage to the switching elements by removing moisture adsorbed between the substrates during the manufacturing process. be able to.

〔Example〕

Hereinafter, the present invention will be specifically explained while comparing it with a conventional manufacturing method.

FIG. 1 is a flowchart of the manufacturing method of the present invention. A method for manufacturing an active matrix electro-optical element according to the present invention will be explained with reference to FIG.

(a゛) An ITO layer is formed by sputtering or vapor deposition on a glass substrate serving as the lower substrate 3, and patterned to form the pixel electrode 5.

(b) A SiNx layer 6, which is a nonlinear resistance film, and a Cr layer, which will become the row electrodes 4, are formed thereon and patterned to form a switching element.

(C゛) IT is placed on the other glass substrate that will become upper substrate 1.
Column electrodes 2 are formed by forming and patterning an O film.

(do) Perform alignment treatment on both glass substrates.

(eo) Apply adhesive to the lower substrate, spray gap agent to the upper substrate, and attach the side substrates.

(fo) Place the bonded substrates in a vacuum dryer and heat at 125° C. for 9 hours and 45 minutes while drawing a vacuum.

The degree of vacuum at this time is from l Torr to I x 10-'T.
It is about orr.

(go) Immediately (within 1 hour at the latest) after completing the previous step, fill the gap between the panels with liquid crystal.

(ho) Connect to the driving circuit.

As can be seen from these, the manufacturing method of the present invention is (fo)
The manufacturing method is almost the same as the conventional manufacturing method shown in FIG. 2, except for the addition of the vacuum heating step.

When the active matrix type electro-optical device manufactured by the above process was subjected to a continuous Vi drive test, the switching device did not break down over time as shown in FIG. 4, and showed extremely high reliability. This is thought to be because most of the moisture inside the panel was removed by heating in a vacuum.

In addition, the vacuum heating mentioned above has a temperature of 100'C and 125'C.
C, 1 hour at 150°C, 30 minutes, 160 minutes, and 90 minutes, but the same effect was confirmed.

〔Effect of the invention〕

As specifically explained in the embodiments above, according to the present invention, by providing a step of heating the substrate while evacuating it immediately before sealing the liquid crystal between the substrates, it is possible to reduce the aging time during driving, which has been a problem in the past. It is possible to prevent the switching elements from being destroyed, and reliability is improved.

[Brief explanation of drawings]

FIG. 1 is a flow chart diagram of the manufacturing process of the present invention,
FIG. 2 is a flowchart of a conventional manufacturing process, FIG. 3 is a plan view of a pixel portion of an MSI panel, D is a sectional view of a pixel portion of an MIS panel, and FIG. 4 is a plan view of a destroyed pixel portion. ■ ・ ・ ・ Upper substrate 2 ・ 3 ・ 4 ・ ・ 5 ・ ・ 6 ・ ・ 7 ・ ・ ・Column electrode, lower substrate, row electrode, pixel electrode, nonlinear resistance film, alignment film, substrate lower substrate that's all

Claims (2)

[Claims] (1) In a method for manufacturing an active matrix iron optical element, in which a liquid crystal is sealed between two substrates with electrodes formed on their surfaces, and a plurality of switching elements are formed on the surface of at least one of the substrates. 1. A method of manufacturing an active matrix electro-optical element, comprising a step of heating the substrates in a vacuum immediately before sealing a liquid crystal between the substrates. (2) The switching element is SiN_x, SiO_x
2. The method for manufacturing an active matrix electro-optical element according to claim 1, wherein the nonlinear element is formed of a film having electrically nonlinear characteristics, such as SiC_x.