JPS6238425A - Production of liquid crystal display cell - Google Patents

Abstract

PURPOSE:To reduce pressure over a mask or the generation ratio of defective parts due to adhesion of dust, fibers or the like especially on a variable display part by rubbing a pair of base boards simultaneously in the same direction, and after masking a fixed display part of one base board, rubbing only the variable display part in the rectangular direction. CONSTITUTION:The upper base board 1 is rubbed in an arrow (a) direction and then the lower base board 2 is rubbed in the same arrow (b) direction same as the upper Lease board. Then, the mask opening the variable display part 3 is arranged on an orientation film of the lower base board 2 to cover the fixed display part 4 and only the variable display part is rubbed in an arrow (c) direction almost rectangular to the arrows (a), (b). Thus, multi- orientation processing for rubbing in both the arrow (b) and (c) directions is applied to the lower base board 2. Since a defect generation ratio at the fixed display part 4 is almost completely removed when a black mask 7 is applied, the defect generation ratio can be remarkably reduced as a whole.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing a TN negative type liquid crystal display cell having a variable display section and a fixed display section, and particularly to an alignment treatment method thereof.

"Prior art and its problems" When a negative type TN type liquid crystal display cell or a TN type guest host liquid crystal display cell has a variable display part and a fixed display part, the variable display part is subjected to TN alignment treatment, and the fixed display part is Processed for parallel alignment. This orientation treatment was performed as follows. In other words, the entire alignment film on the upper substrate is rubbed in one direction, the entire alignment film on the lower substrate is rubbed in a direction almost orthogonal to the upper substrate, and the areas that require parallel alignment treatment are created on the alignment film on the lower substrate. In this method, a mask with openings is placed and rubbing is performed in the same direction as the orientation direction of the upper substrate.

However, in such conventional alignment processing methods,
When a mask is placed on the alignment film of the lower substrate and rubbed, pressure is applied from above the mask, causing dust adhering to the mask and glass surface, fibers generated from the rubbing material, etc. to be applied to the alignment film surface that comes into contact with the mask. This may cause dots or linear defects on the variable display area. Since such defects occurring in the variable display section are easily noticeable, the yield rate is extremely low.

"Objective of the Invention" An object of the present invention is to provide a method for manufacturing a liquid crystal display cell that solves the above-mentioned problems of the prior art, makes it difficult for defective parts to occur in the variable display part, and improves the yield. be.

"Structure of the Invention" A method for manufacturing a liquid crystal display cell according to the present invention includes the steps of (a) forming an electrode film on one side of each of a pair of substrates;
) forming alignment films on the surfaces of the substrates on which the electrode films are formed; (c) rubbing the alignment films of the substrates in the same direction; and (d) one of the substrates. The present invention is characterized by including the step of disposing a mask in which a portion requiring TN type alignment treatment is opened on the alignment film, and rubbing in a direction substantially perpendicular to the alignment direction.

In this way, by masking the parallel orientation portion and performing rubbing for TN orientation wing processing, it is possible to minimize damage and adhesion of dust, fibers, etc. to the TN orientation portion that forms the variable display area. can. On the other hand, there is a possibility that the parallel oriented part may have defects due to damage caused by the mask or the adhesion of dust, fibers, etc. However, the parallel oriented part forms a fixed display part, and numbers and scales can be used as cutout characters on the black mask. , unit display, etc., so the display is a line with a small lighting area, and even if there is some point loss or line breakage, it can be ignored. Therefore, it is possible to maintain good quality and improve yield without being adversely affected by the mask.

``Embodiments of the Invention'' An electrode film is formed on one side of each of a pair of transparent substrates such as glass.6 A transparent electrode film such as an ITO film is formed on the upper substrate on the display side and patterned. Further, on the lower substrate on the back side, an electrode film such as an ITO film or a metal film is formed.

In each substrate, an organic alignment film such as polyimide is further formed on the surface on which the number of electrodes is formed.

The alignment film of the -P substrate is rubbed in the following process.

First, as shown in FIG. 1(a), the upper substrate 1 is rubbed in the direction of arrow a.

Next, as shown in FIG. 1(b), the lower substrate 2 is replaced with the upper substrate l.
Rub in the same direction as the arrow.

Furthermore, as shown in FIG. 1(c), a mask in which the variable display section 3 is opened is placed on the alignment film of the lower substrate 2 to cover the fixed display section 4, and approximately Rub in the orthogonal direction of arrow C.

In this way, the lower substrate 2 is moved in the direction indicated by the arrow C and
A multi-orientation treatment with directional rubbing is performed.

As shown in FIGS. 3, 4, and 5, the upper substrate 1 and lower substrate 2 obtained in this way are placed opposite each other and bonded to the periphery with a sealing material 5 interposed therebetween, and a TN type liquid crystal 8 is injected inside. do. As a result of the alignment treatment, the liquid crystal 6 has the variable display section 3 aligned in a straight line, and the fixed display section 4 aligned parallel to each other.

Further, a black mask 7 is attached to the display surface of the upper substrate 1. In the black mask 7, an opening 7a is formed in the variable display section 3, and a display 7b consisting of cut-out characters is formed in the fixed display section 4. Then, polarizing plates (not shown) are arranged on the outer sides of the upper substrate 1 and the lower substrate 2 in parallel Nicols.

In this liquid crystal display cell, when a light source is installed on the back side of the lower substrate 2 and a transmission type display is performed, in the fixed display section 4, since the liquid crystal 6 is aligned in parallel, light passes through as it is, and the black mask 7 Display formed in? b will be lit. In addition, in the variable display section 3, the liquid crystal 8 is TN
Since they are oriented, light does not pass through them at all times, but when a voltage is applied, light passes through only the portions where the liquid crystals 6 are aligned in parallel, and the lights are turned on.

On the other hand, for comparison, the rubbing of the lower substrate 2 is shown in FIG.
), after rubbing the entire surface in the direction of arrow C, a mask was placed to cover the variable display section 3, and the fixed display section 4 was rubbed in the direction of arrow B. Using this lower substrate 2, a liquid crystal display cell was produced in the same manner as above. The defect occurrence rate of the liquid crystal display cell according to the above example and the liquid crystal display cell according to the comparative example was measured. The results are shown in Table 1.

As described above, before the black mask 7 is pasted, the total defect occurrence rate of the fixed display section 4 and the variable display section 3 is the same between the example and the comparative example. However, when the black mask 7 is attached, in the example, the defect occurrence rate in the fixed display section 4 is almost eliminated, so that the defect occurrence rate as a whole is significantly reduced. On the other hand, in the comparative example, even if the defect occurrence rate in the fixed display section 4 disappears, the defect occurrence rate in the variable display section 3 is high, so that the defect occurrence rate increases as a whole.

(Hereinafter, blank space) Table 1 "Effects of the Invention" As explained above, according to the present invention, after rubbing a pair of substrates in the same direction, the fixed display portion of one substrate is masked to display a variable display. Since the rubbing is performed in a direction almost perpendicular to the above, the incidence of defects due to pressure from above the mask or adhesion of dust, dust, etc. is reduced, especially in the variable display section, and overall defects are reduced. The incidence of this can be significantly reduced. Therefore, the yield can be improved.

[Brief explanation of the drawing]

FIG. 1(a), FIG. 1(b), and FIG. 1(c) are diagrams showing the rubbing process in the example of the present invention in the order of steps, and FIG. 2 is a diagram showing the liquid crystal display cell obtained in the same example. 3 is a front sectional view of the same liquid crystal display cell, and FIG. 4 is a side sectional view of the same liquid crystal display cell. In the figure, 1 is an upper substrate, 2 is a lower substrate, 3 is a variable display section, 4 is a fixed display section, 6 is a liquid crystal, and a, b, and c are rubbing directions. Figure 3 Figure 2 Figure 4

Claims (1)

[Claims] A method for manufacturing a TN negative type liquid crystal display cell in which a variable display section is subjected to TN alignment treatment and a fixed display section is subjected to horizontal alignment treatment, which includes the steps of (a) forming an electrode film on one side of each of a pair of substrates, and (b) ) forming alignment films on the surfaces of the substrates on which the electrode films are formed; (c) rubbing the alignment films of the substrates in the same direction; and (d) one of the substrates. on the alignment film of
A method for manufacturing a liquid crystal display cell, comprising the steps of: arranging a mask with openings in areas requiring TN type alignment treatment, and rubbing in a direction substantially perpendicular to the alignment direction.