JPH05323321A - Production of liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide a method for producing a liq. crystal display device by which static electricity generated at the time of rubbing a film to be oriented on each electrode substrate of a liq. crystal display cell is easily reduced without requiring large-scale equipment and the breakdown of a switching element and the film to be oriented on the substrate is prevented. CONSTITUTION:When a liq. crystal orienting layer is formed, an electric conductive liq. is fed as vapor or mist from the inside of a rubbing roll 5 with wound rubbing cloth 4 to the cloth 4 through the pores 3 in the roll 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal display device, and more particularly to a method of forming a liquid crystal alignment layer thereof.

[0002]

2. Description of the Related Art Generally, as shown in a sectional view of FIG. 5, a liquid crystal display element has an upper substrate 13 and a lower substrate 14 made of glass or the like, which are arranged in parallel with each other at a predetermined interval, and the peripheral portion thereof. In order to keep the space between the upper substrate 13 and the lower substrate 14 at a predetermined width in an internal space formed by sealing with a sealing material 15 such as resin or glass frit,
A spacer 16 made of resin or glass is arranged and a liquid crystal 17 is enclosed. The upper substrate 13 and the lower substrate 14
An upper electrode 18 and a lower electrode 19 each having a predetermined pattern made of a transparent electrode film are formed on the inner surface of the liquid crystal, and an alignment layer for aligning the liquid crystal in a certain direction is formed on the surface in contact with the liquid crystal. Membranes 20 and 21 are formed. Such alignment films 20 and 21 are subjected to a so-called rubbing treatment in which the surface of a thin film made of polyimide, polyamide or the like formed on a substrate having upper electrodes 18 and lower electrodes 19 is rubbed in a certain direction with rayon cloth or the like. It is formed by. In the case of a twisted nematic type (hereinafter, referred to as TN type) liquid crystal display element that is most often used at present, the alignment film 20 formed on the upper substrate 13 causes the liquid crystal to be aligned on the lower substrate 14. The formed alignment films 21 are arranged so that the directions in which the liquid crystals are aligned are orthogonal to each other. Further, outside the upper substrate 13 and the lower substrate 14, the upper polarizing plate 22 and the lower polarizing plate 2 are provided, respectively.
3 are arranged so that their polarization axis directions are orthogonal or parallel to each other. Among the TN type liquid crystal display elements, what is called a simple matrix type is one in which strip-shaped transparent electrodes are provided on each of an upper substrate and a lower substrate and arranged so as to be orthogonal to each other. The active matrix type has a switching element such as a transistor provided in each pixel.

As a method of performing a rubbing process in an actual process, a rubbing roller 25 having a rubbing cloth 4 wound around the outer circumference of a roll 24 is rotated as shown in the sectional view of FIG. There is a method of moving the stage 7 on which the substrate to be rubbed 6 having the surface of is mounted.

[0004]

However, polyimide and polyvinyl alcohol (PV
A), rayon and nylon used as a rubbing cloth are materials that easily generate static electricity, and the rubbing cloth and the surface of the alignment film are usually charged to 1 kV or more during the rubbing process. This static electricity destroys the switching element in the active matrix type. Further, in both the active matrix type and the simple matrix type, a display defect occurs due to damage of the electrodes and the alignment film due to static electricity discharge, and adsorption of foreign matter due to electrostatic force, leading to a reduction in yield of liquid crystal display elements.

Conventionally, as a countermeasure against static electricity in the rubbing process, a method of rubbing by grounding a rubbing cloth and a substrate to be rubbed (JP-A-63-144325),
A method of releasing generated static electricity, such as a rubbing method using a conductive rubbing cloth (Japanese Patent Laid-Open No. 61-123816), or a method of rubbing while blowing ionized air on the rubbing cloth and the substrate to be rubbed (Japanese Patent Laid-Open No. Sho-61-13816). 62-172323), a method for controlling humidity in a room for rubbing treatment, and a method for rubbing by rubbing a conductive liquid from the outside on a rubbing cloth or a substrate to be rubbed (JP-A-61-67022). 61-24
No. 9020), there is a method of suppressing generation of static electricity itself.

Among these measures against static electricity, the method of discharging static electricity generated by grounding a substrate or a rubbing cloth or using a conductive rubbing cloth involves the movement of electric charges, and therefore switching elements and The risk of damaging the electrodes remains. Therefore, as a measure against static electricity, it is preferable to suppress the generation of static electricity itself, but the method of rubbing while blowing ionized air on the rubbing cloth and the substrate to be rubbed has a low static elimination effect and is a method of controlling the humidity of the entire room. Has high equipment and maintenance costs. Further, the method of adhering the conductive liquid from the outside has a problem that the excess liquid is scattered and maintenance of the machine becomes difficult.

The present invention has been made to solve the above problems, and does not require large-scale equipment,
An object of the present invention is to provide a method for manufacturing a liquid crystal display device capable of reducing static electricity generated when rubbing an alignment film on an electrode substrate of a liquid crystal display element without scattering extra liquid.

[0008]

A method of manufacturing a liquid crystal display device according to the present invention comprises a method of vaporizing a conductive liquid from the inside of a rubbing roller wound with a rubbing material when forming a liquid crystal alignment layer,
Alternatively, it is supplied to the above rubbing material in a mist state or through a porous body. It is possible to suppress the generation of static electricity by rubbing the conductive liquid from the inside of the rubbing roller in the state of vapor or mist, or while supplying it to the rubbing cloth in an appropriate amount through the porous body. is there.

[0009]

According to the rubbing method of the present invention, since the rubbing treatment can be performed in the state where the conductive liquid is present on the rubbing cloth and the substrate, the static electricity generated by the rubbing can be suppressed.

[0010]

【Example】

Example 1. FIG. 1 is a perspective view showing a rubbing roll of a rubbing device used in a method of manufacturing a liquid crystal display device according to an embodiment of the present invention. The roll 1 can introduce steam or mist from the shaft 2, and the small holes 3 through which the steam or mist introduced from the shaft 2 can be blown to the roll surface.
have. FIG. 2 is a cross-sectional explanatory view for explaining the rubbing method according to this embodiment showing the rubbing roll portion. A rubbing roller 5 having a rubbing cloth 4 wound around the outer periphery of the roll 1 is rotated, and a stage 7 on which a rubbing substrate 6 having an alignment film formed on the surface thereof is placed is moved underneath to perform rubbing.

In the method of this embodiment, a rubbing roller 5 having a mechanism for atomizing water from the shaft 2 with steam or ultrasonic waves to supply it to the rubbing cloth 4 is rotated, and the bottom of the rubbing roller 5 is oriented on the surface. The rubbing treatment is performed by passing the film-formed rubbing substrate 6. In this embodiment, the amount of water vapor or water atomized to be supplied from the shaft 1 is 0.5 to 1 ml per minute, the rotation speed of the rubbing roller 5 is 200 to 400 rotations per minute, and the substrate to be rubbed 6 is rubbed. The thickness of the polyimide alignment film on the surface is 200-
1000 Å, rubbing load is 200-500 g, thickness of rubbing cloth 4 used is about 2 mm, moving speed of stage 7 is 5-20 mm / sec, angle of the rubbing roller 5 and the traveling direction of the substrate 6 to be rubbed is 45 ° is suitable. Is.

As a result of manufacturing a liquid crystal display element using the method of this embodiment, it was possible to manufacture a liquid crystal display element with fewer display defects than before.

Embodiment 2. FIG. 3 is a perspective view showing a rubbing roll of a rubbing device used in another embodiment of the present invention. The roll 8 can introduce the liquid through the shaft 9, and has a small hole 10 on the surface through which the liquid introduced through the shaft 9 can be discharged. FIG. 4 is a cross-sectional explanatory view illustrating a rubbing roll portion of a rubbing method according to another embodiment. The porous body 11 is provided around the roll 8.
Then, the rubbing roller 12 having the rubbing cloth 4 wound around it is rotated, and the stage 7 on which the rubbing substrate 6 having the alignment film formed on the surface thereof is placed under the rubbing roller 12 is moved to perform rubbing.

In this embodiment, the amount of water supplied from the shaft 8 is 0.5 to 1 ml, and other rubbing conditions are the same as in the first embodiment. Similarly, as a result of manufacturing a liquid crystal display element by using the method of this example, it was possible to manufacture a liquid crystal display element with fewer display defects than before.

[0015]

As described above, according to the present invention, when the liquid crystal alignment layer is formed, the conductive liquid is vaporized or fog from the inside of the rubbing roller wound with the rubbing material, or the porous body is used. Supplied to the rubbing material via
Since an appropriate amount of humidity is applied, static electricity generated during rubbing can be reduced, so it is possible to prevent damage to the switching elements due to static electricity and display defects due to adsorption of dust, and to improve the yield of liquid crystal display elements. It is possible to improve the quality and quality.

[Brief description of drawings]

FIG. 1 is a perspective view showing a rubbing roll used in an embodiment of the present invention.

FIG. 2 is an explanatory sectional view showing a rubbing method according to an embodiment of the present invention.

FIG. 3 is a perspective view showing a rubbing roll used in another embodiment of the present invention.

FIG. 4 is a sectional explanatory view showing a rubbing method of another embodiment of the present invention.

FIG. 5 is a sectional view showing a structure of a typical TN type liquid crystal display element according to the present invention.

FIG. 6 is a cross-sectional explanatory view showing a conventional rubbing method.

[Explanation of symbols]

 1 roll 2 roll shaft 3 small hole 4 rubbing cloth 5 rubbing roller 6 rubbing substrate 7 stage 8 roll 9 roll shaft 10 small hole 11 porous body 12 rubbing roller

Claims (1)

[Claims] 1. A method of manufacturing a liquid crystal display device, comprising forming a liquid crystal alignment layer by rolling a rubbing material on a surface of a thin film which is in contact with liquid crystal on a substrate having an electrode, wherein the rubbing material is formed when the liquid crystal alignment layer is formed. A method for manufacturing a liquid crystal display device, characterized in that a conductive liquid is supplied from the inside of a rubbing roller wound with the above to the above rubbing material in a vapor or mist state or via a porous body.