JPS5945126B2 - Manufacturing method of liquid crystal display element - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a liquid crystal display element.

Conventionally, in a liquid crystal display element for displaying characters, numbers, etc., an alignment control film made of silicon oxide, SiO2, etc., has been applied to the surface of the pattern electrode side of both substrates constituting the liquid crystal display element in order to improve the display characteristics. I'm trying to form it.
To form this alignment control film, (a) a film of silicon oxide 5102 or the like is formed by vapor deposition on the surface of the substrate on the pattern electrode side, and the film surface is rubbed in a predetermined direction with a cloth or the like.

(b) Alternatively, it is performed by diagonally depositing at a predetermined angle on the surface of the substrate on the pattern electrode side.

However, in the rubbing method of (a), the range in which the pretilt angle of the liquid crystal molecules, that is, the angle formed by the long axis of the liquid crystal molecules with respect to the alignment control film surface of the substrate of the liquid crystal display element in the absence of an electric field, can be controlled is narrow. In addition, when a predetermined voltage is applied to the pattern electrode, alignment defects (reverse tailed disclination) of liquid crystal molecules, in other words, induced domains are likely to occur. The display characteristics of liquid crystal cells constructed with such substrates were unsatisfactory.

Further, a rubbing operation is required in addition to the operation of forming the alignment control film, and therefore the productivity of the substrate for a liquid crystal display element is not good. On the other hand, in the oblique deposition method (b), although the pretilt angle can be controlled over a larger range than in the method (a), the ratio Vsat/Vth of the saturation voltage Vsat to the threshold voltage Vth is large, i.e. , the steepness was insufficient and the contrast characteristics were not good.

In addition, the oblique evaporation work itself is a troublesome work, so
The productivity of substrates for liquid crystal display elements was not good. This invention has been made to solve the various drawbacks mentioned above, and is made by spraying a liquid substance in the form of a mist onto the surface of the pattern electrode while rotating a substrate provided with a desired pattern electrode in a centrifuge, thereby creating a liquid crystal display. It is designed to form an alignment control film that controls the alignment of molecules, making it possible to control the pretilt angle in a liquid crystal display element over a wide range, and also to reduce Vsat/
It is an object of the present invention to provide a method for manufacturing a liquid crystal display element that can have a small Vth value and good contrast characteristics, and can be manufactured at low cost with simple operations without the risk of staining the surface of an alignment control film. do.

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of an apparatus applicable to the present invention, in which 1 is a rectangular substrate such as a glass plate, and one surface of this substrate 1 is coated with silicon oxide (SiO2) by a screen printing method or the like. A transparent pattern electrode 2 in the shape of a square is provided.

Reference numeral 3 denotes a rotating drum of a centrifuge, and a fixing member (not shown) is provided along the inner peripheral surface of the rotating drum 3 so that the substrate 1 faces the pattern electrode 2 side toward the center of the rotating drum 3 and the axis of the surface. 01 is fixed so as to form a predetermined angle with respect to the rotation direction A of the rotating drum 3.

In the internal space of this rotating drum 3, a nozzle 4 of a spraying device is installed.
is arranged toward the inner peripheral surface of the rotating drum 3, and as shown by the broken line in the figure, a liquid substance 5 for forming an alignment control film, for example, a silanol solution, is sprayed from a nozzle 4 toward the substrate 1. It's getting old. Next, a method for forming an alignment control film on a liquid crystal display element substrate using the above-described apparatus will be described.

First, the substrate 1 is attached to the fixing member of the rotary drum 3 of a centrifuge as described above, and the rotary drum 3 is heated several hundred R. p
．． Rotate 5 times in the direction of arrow A at a slow speed of m.

In this state, a liquid substance 5 of silanol solution is atomized and sprayed toward the substrate 1 from the nozzle 4 of the spraying device, and the atomized substance 5 of the liquid substance 5 is attached to the surface of the substrate 1 on the pattern electrode side. let In this way, the substrate 1
As shown in FIG. 2, a large number of hemispherical nuclei 6 of condensed silicon oxide SiO2 scattered in a dotted manner are formed on the surface of the pattern electrode side.

Next, while stopping the spraying of the liquid substance 5, the rotating drum 3 is rotated at high speed in the direction of arrow A for several minutes.

Thereafter, by increasing the rotational speed of the rotating drum 3 and spraying the liquid substance 5, the liquid substance 5 is deposited on each nucleus 6 in a direction opposite to the rotation direction A of the rotating drum 3 of the centrifuge. Orientation control film 7 having polarity in a predetermined direction on the surface
form.

Then, the operation of spraying the liquid substance 5 from the nozzle 4 is stopped, and the rotating drum 3 is driven to rotate at a slow speed.
The alignment control film 7 formed on the substrate 1 is pre-dried, and then the pre-dried substrate 1 is dried in an oven or the like.
This completes the liquid crystal display element substrate 8.

In this way, as shown in FIG. 3, a spray of silanol solution is attached to the surface of the substrate 1 on the pattern electrode 2 side based on a large number of nuclei 6 as shown in FIG. An anisotropic alignment control film 7 is obtained in which a large number of inclined portions 7a are formed, each having a steeply inclined surface on the rotation direction A side of the rotating drum 3 and a gentle inclined surface on the opposite side.

Note that the anisotropic axis direction of the alignment control film 7 of the substrate 1, that is,
The direction of the normal line 02 of each inclined portion 7a of the orientation control film 7 is determined by the direction of the substrate relative to the rotation direction A of the rotary drum 3 via a fixing member (not shown) disposed within the rotary drum 3 of the centrifuge. This can be determined by setting the direction of axis 01 of 1 at a predetermined angle.

Two liquid crystal display element substrates 8, 8 manufactured as described above.
As shown in FIG. 4, the films 7, 8 of each substrate 8,
The liquid crystal display element 11 is formed by bonding the liquid crystal display elements 7 parallel to each other at a predetermined interval with spacers 9 such as frits interposed therebetween.

Both substrates 8, 8 and spacer 9 of this liquid crystal display element 11
Into the space formed by a known vacuum pouring method,
Liquid crystal 13 is inserted through an injection hole 12 formed in one substrate 8.
Further, a polarizing plate 14 is injected onto each outer surface of both substrates 8, 8.
, 14 are attached to complete a liquid crystal display element for a liquid crystal display device. In this way, in the liquid crystal display element 11 manufactured using the substrate 8, the rotational speed of the rotating drum 3 of the centrifuge, the viscosity of the liquid substance 5 for forming the alignment control film, and the flow rate from the nozzle 4 of the liquid substance 5 are determined. By adjusting the spray pressure, the pretilt angle of the liquid crystal molecules in a state where no voltage is applied between the pattern electrodes 2, 2 of both substrates 8, 8 can be kept within a larger range than when using conventional substrates. In other words, it can be set to have a large orientation control force, and when a predetermined voltage is applied between the electrodes 2, 2, orientation defects (reverse tailed disclination), Good display characteristics can be obtained without the risk of generating induced domains.

Further, the alignment control film 7 of the substrate 8 can have a stronger alignment regulating force than that by the conventional method, and in particular, can make the threshold direct voltage Vth larger than that by the conventional oblique vapor deposition method.

Therefore, the steepness can be set to a large value, and good contrast characteristics can be obtained. Furthermore, since the alignment control film 7 on the substrate 8 can be formed without wrapping, there is no risk of surface contamination, and the reliability of the liquid crystal display element can be improved accordingly. It has various advantages, such as not requiring complicated operations such as oblique vapor deposition, and being easily manufactured with a small number of steps.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is an explanatory diagram of a schematic configuration of a device applicable to the present invention;
Fig. 2 is an explanatory diagram of the state of the substrate for a liquid crystal display element in an intermediate step of the present invention, Fig. 3 is an explanatory diagram of the completed state of the substrate of Fig. 2, and Fig. 4 is an embodiment of the liquid crystal display element according to the present invention. FIG. 1...Substrate, 2...Pattern electrode, 3
... Rotating drum of centrifuge, 4 ... Nozzle of spraying device, 5 ... Liquid substance for forming alignment control film, 6 ... Nucleus, 7...Alignment control film, 7a...Slanted portion, 8...Substrate for liquid crystal display element, 11...Liquid crystal display element.

Claims (1)

[Claims] 1. A substrate on which a patterned electrode is formed is placed on the surface of a rotating drum, and while the rotating drum is rotating at a low speed, a liquid substance that will become the source of a liquid crystal alignment control film is directed from a nozzle of a spraying device toward the substrate. A hemispherical nucleus is formed on the surface of the substrate by spraying in a mist, and then the liquid substance is sprayed in a mist from a nozzle of the spraying device while the rotating drum is rotating at high speed. A method for manufacturing a liquid crystal display element, characterized in that an alignment control film having a large number of inclined surfaces inclined in a predetermined direction is formed on the surface of the substrate.