JPH0132963B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for aligning a liquid crystal cell substrate.

Various types of field-effect liquid crystal cells are used as display devices, and the orientation state of the liquid crystal molecules can be classified into liquid crystal cell substrates (substrates that sandwich liquid crystals).
There are two types of display bodies: horizontal alignment, which is parallel to , and vertical alignment, which is perpendicular to .

Here, an example of a horizontal alignment treatment method in a conventional liquid crystal cell manufacturing process is shown in FIG. A drum 1 on which a cloth 12 is wrapped around a liquid crystal cell substrate 11 on which a resin such as Teflon or polyimide is coated and baked or vapor-deposited.
In step 3, rub while applying pressure. As a result, microscopic scratches are formed on the surface of the alignment agent, and the alignment process is completed. In such an orientation process,
Because a large amount of pressure is applied to the liquid crystal cell substrate, cracks occur in the substrate, resulting in a decrease in yield.At the same time, it is difficult to perform a rubbing process with an even pressure, resulting in disordered alignment and uneven display color. Furthermore, the cloth needed to be replaced frequently due to wear.

Furthermore, as another conventional alignment treatment method, a method of obliquely vapor depositing silicon oxide or the like has been used.
However, this method has the disadvantage that uniform orientation is difficult to obtain because the angle of oblique deposition differs depending on the direction of deposition of the deposit.

An object of the present invention is to provide an alignment processing method that eliminates such drawbacks, eliminates the need for frequent cloth replacement, and enables uniform alignment processing without cracking of liquid crystal cell substrates.

Hereinafter, a method for aligning a liquid crystal cell substrate according to the present invention will be described with reference to the drawings.

FIG. 2 is a principle diagram showing the orientation treatment method according to the present invention. A magnet roll consisting of a cylindrical sleeve 21 and a magnet 22 built into the cylindrical sleeve has a means for rotating the magnet roll, and magnetic powder is magnetically attracted to the surface of the sleeve to drive a magnetic brush 23. Form. When the rotating magnetic brush rubs the surface of the liquid crystal cell substrate 24, microscopic scratches are formed on the surface of the liquid crystal cell substrate, thereby aligning the liquid crystal within the liquid crystal cell. It should be noted that using this method is sufficient to achieve the above objectives such as uniform orientation treatment, but the density of the ears of the magnetic brush is sparse and the length of the ears varies, which tends to cause uneven orientation. In order to solve this problem, it is desirable to regulate the length of the magnetic brush uniformly and to perform rubbing repeatedly. For this reason, it is effective to fix one of the sleeve and the magnet that constitute the magnet roll, and rotate the other to rotate the magnetic brush on the sleeve. That is, by selecting an appropriate amount of magnetic powder and providing a blade 34 for regulating the length of the magnetic brush ears, a magnetic brush 33 shown in FIG. 3 is formed on the surface of the sleeve 31 of the magnet roll, and the magnetic brush is placed on the sleeve. Rotate with. Using such a magnetic brush, it becomes possible to perform a more uniform alignment process. Details will be explained below using examples.

Example 1 A magnet rotation type magnetic brush alignment method according to the present invention will be explained. A 12-pole magnet with a magnetic field strength of 1000 Gauss is placed inside a cylindrical sleeve with an outer diameter of 30 mm and a length of 30 cm.The sleeve is fixed and only the magnet is rotated by a motor. Particle size on sleeve surface
Apply 2 to 3 g of iron powder of 50 μm or less, and set the gap between the blade and the sleeve to about 500 μm. When the rotation speed of the magnet is 60 to 2000 RPM, a magnetic brush with a uniform length of 500 μm is formed on the sleeve surface, and the magnetic brush rotates at a high speed of 360 to 12000 RPM. On the other hand, when the liquid crystal cell substrate and the sleeve were passed through with a gap of 300 to 400 μm, the liquid crystal cell substrate was subjected to a uniform rubbing treatment, and a liquid crystal cell having no domains and exhibiting good alignment was obtained.

Example 2 A sleeve rotating magnetic brush orientation method according to the present invention will be described. The sleeve and magnet used here are those described in Example 1. In the sleeve rotation method, in order to maintain a constant gap between the sleeve and the liquid crystal cell substrate, the sleeve is held by a guide roller, and in order to further regulate the length of the magnetic brush, the blade is placed between the magnetic poles on the outer periphery of the sleeve. The gap distance with the sleeve is 500μm.
shall be. Two pieces of iron powder with a particle size of 50 μm or less are placed on the sleeve.
~3g was applied and rubbing was performed by passing the liquid crystal cell substrate through the sleeve rotating at 60 to 1000 RPM, and good alignment characteristics were obtained.

As mentioned above, unlike conventional rubbing using cloth, the present invention enables uniform rubbing treatment with small pressure, and since it uses hard materials, it can be applied to any material from Teflon or polyimide to silicon oxide film, tin oxide or indium oxide. The object of the present invention is to provide an orientation method that allows rubbing treatment on materials, causes less wear, and is easy to maintain. In the embodiments, a magnet rotation method and a sleeve rotation method have been described as means for rotating the magnetic brush on the sleeve, but it is also possible to rotate both the magnet and the sleeve, and the same effect can be obtained. .
As described above, according to the alignment treatment method of the present invention, there is an excellent effect that it is possible to eliminate the need for frequent cloth replacement, eliminate cracks in the liquid crystal cell substrate, and enable uniform alignment treatment.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional alignment treatment method. FIGS. 2 and 3 are explanatory diagrams of the orientation treatment method of the present invention. 11...Liquid crystal cell substrate, 12...Rubbing cloth, 13...Drum, 21...Sleeve, 22...
...Magnet, 23...Magnetic brush, 31...Sleeve, 32...Magnet, 33...Magnetic brush, 34...Blade.

Claims (1)

[Scope of Claims] 1. In a method for aligning a liquid crystal cell substrate, magnetic powder is magnetically attracted to the surface of the cylindrical sleeve using a cylindrical sleeve and a magnet roll equipped with a magnet built into the cylindrical sleeve. After forming a magnetic brush with the magnetic powder and rotating the magnetic brush by rotating at least one of the cylindrical sleeve and the magnet, the liquid crystal cell substrate is passed near the cylindrical sleeve to remove the liquid crystal cell. A method for aligning a liquid crystal cell substrate, comprising performing a rubbing process on the substrate using the magnetic brush. 2. The method for aligning a liquid crystal cell according to claim 1, wherein a blade is provided near the surface of the cylindrical sleeve to regulate the height of the magnetic brush formed of the magnetic powder.