JPH04221925A - Method and apparatus for producing substrate for liquid crystal display panel - Google Patents

Abstract

PURPOSE:To improve the effect of removing the dust and foreign matter sticking to a substrate for liquid crystal display panels at the time of a rubbing treatment and to improve the quality and yield of the liquid crystal display device by applying a film for orientation on the substrate to be used particularly for the liquid crystal display device, then subjecting the substrate to brush washing by using a detergent. CONSTITUTION:At least a driving electrode (2) and the coating film (3) for orientation are laminated and formed on the transparent substrate (1) and the surface of this coating film (3) for orientation is rubbed then washed in this method and apparatus for producing the substrate for liquid crystal display panels. The above-mentioned method and apparatus are so constituted that the above-mentioned washing is brush washing and that the brushing direction is parallel with the rubbing direction at the time of the above-mentioned rubbing and particularly opposite.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for manufacturing a substrate for a liquid crystal display panel. Specifically, after applying an alignment film to a substrate used in a liquid crystal display device and performing a rubbing process, brushing cleaning using a cleaning liquid improves the removal effect of dust and foreign matter that adheres during the rubbing process, and improves the effectiveness of the liquid crystal display. The present invention relates to a method and apparatus for manufacturing a substrate for a liquid crystal display panel to improve the quality and yield of display devices.

0002

2. Description of the Related Art Liquid crystal display devices have a low driving voltage and are inexpensive, so they are being actively introduced into the field of office automation equipment such as personal computers and word processors. Liquid crystal display panels used for these applications are required to display characters and graphics, so they are inevitably moving toward larger screens, more pixels, and higher definition.
There is a need for manufacturing methods and manufacturing equipment for manufacturing high-quality liquid crystal display panels that are free from display defects.

[0003] A liquid crystal display panel is made of two transparent substrates.
On each striped transparent electrode made of ITO (In2O3 - SnO2), an alignment coating film,
For example, a polyimide resin film is applied, rubbed with a rubbing cloth for alignment, then thoroughly washed and dried, and the two substrates are placed one on top of the other with a narrow gap between them, and the liquid crystal is injected and sealed between them. .

The alignment treatment by rubbing stabilizes the alignment of liquid crystal molecules and determines display performance, and the cleaning treatment after rubbing removes foreign matter and dust that adheres to the substrate before and after rubbing, improving the quality of the liquid crystal display panel. This is an extremely important process for improving yield.

FIG. 3 is a diagram showing an example of a conventional rubbing/cleaning device.
indicates a cleaning device. For example, in FIG. 4A, a cassette 10 containing transparent substrates 1 is set on a loader 11, and the transparent substrates 1 are fed into the substrate transport mechanism of the rubbing processing mechanism 12 one by one. The transparent substrate 1 that has been rubbed by the rubbing mechanism 12 is stored in another cassette 10 by the unloader 16, and the rubbing process is completed. Next, the cassette 10 is transferred to a batch-type cleaning device as shown in FIG. For example, IP
It is immersed in an ultrasonic cleaning tank 301 filled with A (isopropyl alcohol) and cleaned with ultrasonic waves, and if necessary, immersed in an ultrasonic cleaning tank 302 filled with a neutral detergent aqueous solution and cleaned with ultrasonic waves. . Furthermore, it is immersed in an ultrasonic cleaning tank 303 filled with pure water and cleaned using ultrasonic waves.Finally, after being rinsed in a pulling tank 304 filled with pure water, it is heated by, for example, infrared rays. It is dried in a drying oven 305 to complete the cleaning and drying process after the rubbing process.

FIG. 2 is a diagram illustrating the effects of rubbing and foreign matter. FIG. 2(a) is a perspective view showing the rubbing direction, and FIG. 2(b) is a side view illustrating the rubbing situation. Normally, the rubbing roller 22 and the substrate 1 are often arranged at a certain angle, for example, about 30 degrees, in order to give the twist angle of the liquid crystal molecules, so that the rubbing direction 200 is schematically shown in FIG. As shown in the figure, it is formed to intersect with the end surface of the substrate 1. On the other hand, a rubbing cloth 220 is wrapped around the rubbing roller 22, as shown in FIG. For example, the rubbing cloth 220 has a thickness of 0
．． It is a base fabric made of nylon with a thickness of about 7 mm, and a so-called pile (tip) 221 of fibers with a thickness of about 30 μmφ and a length of about 3 mm is planted perpendicular to the base fabric surface.

That is, the rotating rubbing cloth 220
A substrate 1 is placed below on a stage (not shown) (on which are striped drive electrodes 2 made of, for example, an ITO film, and a film with a thickness of 5 coated by, for example, a transfer printing method).
When the orientation coating film 3 (on which a polyimide resin film with a thickness of 0 to 100 nm has been formed in advance) is carried in, the surface of the orientation coating film 3, for example, a polyimide resin film, is piled into a pile 22.
1 is rubbed, strain anisotropy is imparted in the rubbing direction perpendicular to the rubbing roller 22 to form an alignment film, which stabilizes the alignment of liquid crystal molecules at the interface of the alignment film injected into the liquid crystal display panel. can give a twist angle of Note that the rubbing roller rotation mechanism, stage drive mechanism, and the like are not directly related to the present invention, so illustration and description thereof are omitted.

After performing the rubbing process described above, the alignment film forming process is completed by cleaning and drying using the cleaning apparatus described in FIG. 3(b).

[0009]

[Problem to be Solved by the Invention] Normally, when the surface of the alignment coating film 3 is closely observed, foreign matter 100 as shown in FIG. 2(b), for example, fine particles of resin or metal, are attached. Therefore, when rubbing is performed on such a film, dirt 1 is deposited on the opposite side of the direction of movement of the rubbing roller 22.
01. For example, broken pieces of the pile 221 planted on the rubbing cloth 220 and other debris often adhere to the rubbing cloth 220.

Conventionally, the alignment film surface is rubbed for fear of deteriorating the alignment performance obtained by rubbing.
Scrub cleaning is disliked, and as mentioned above, ultrasonic cleaning is generally performed in a cleaning solution.

However, in such ultrasonic cleaning, not only the foreign matter 100 that has bitten into the alignment film surface but also the dust 101 are removed.
The removal effect is not necessarily sufficient, and it also causes scratches on the alignment film, both of which cause defects in the display quality of liquid crystal display devices, which is a serious problem that needs to be solved.

0012

[Means for Solving the Problems] The above-mentioned problem is solved by a liquid crystal display in which at least a drive electrode 2 and an alignment coating film 3 are laminated on a transparent substrate 1, and the surface of the alignment coating film 3 is rubbed and then cleaned. This problem can be solved by a method for manufacturing a substrate for a liquid crystal display panel in which the cleaning is brushing cleaning, and the brushing direction is parallel to the rubbing direction during the rubbing. In particular, the problem can be effectively solved by making the brushing direction for cleaning and the rubbing direction for rubbing opposite to each other. Specifically, a brushing cleaning mechanism 13 is provided directly after the rubbing treatment mechanism 12 that rubs the orientation coating film 3, and the rubbing roller 22 of the rubbing treatment mechanism 12 and the brushing roller 23 of the brushing cleaning mechanism 13 are provided. This problem can be solved by an apparatus for manufacturing a substrate for a liquid crystal display panel, which is configured by arranging these in parallel.

[0013]

According to the present invention, foreign matter 100 that has dug into the alignment film surface and strongly adhered dust 101, which are difficult to remove by ultrasonic cleaning, can be easily removed by brushing. Moreover, the pile of the brush is slightly weakened and the brushing direction is the same as the rubbing direction 200 during rubbing, so the orientation performance obtained by the rubbing process is not degraded, so the cleaning effect is high. , Moreover, display quality and yield are improved.

[0014]

[Embodiment] Fig. 1 shows an embodiment of the present invention. Fig. 1 (a) shows the configuration of an apparatus for sequentially performing rubbing, washing, and drying, and Fig. 1 (b) shows the rubbing processing mechanism. The main part of the same figure (c) is the main part of the brushing cleaning mechanism, and the same figure (c) is a conceptual diagram showing the state of brushing cleaning.

In the figure, 13 is a brushing cleaning mechanism, 14
1 is a shower cleaning machine, 15 is a dryer, 17 is a substrate transport mechanism, 23 is a brushing roller, 33 is a cleaning liquid injection pipe, 2
30 is a pile planted in the brushing cloth.

[0016] The same parts as those explained in the above drawings are given the same reference numerals, and the explanation of the same parts will be omitted. For example, thickness 1.1 mm,
A striped drive electrode 2 made of ITO (In2O3-SnO2) is formed on a glass transparent substrate 1 with a size of about 350 x 400 mm, and then a polyimide resin film, for example, is applied to a thickness as an alignment coating 3. 50-10
Coat to 0 nm.

In FIG. 3A, a cassette 10 containing the processed transparent substrates 1 is set on a loader 11, and the substrates are fed into the substrate transport mechanism 17 of the rubbing mechanism 12 one by one. The substrate that has been rubbed in the rubbing processing mechanism 12 is directly transferred to the directly connected brushing cleaning mechanism 13 where it is brushed and cleaned.
After performing shower cleaning using, for example, pure water in a shower washer 14 directly connected to the brushing cleaning mechanism 13, the cassettes are subsequently dried in a dryer 15 using an air knife or infrared heating, and then transferred to another cassette 10 by an unloader 16. The processing substrate 1 is housed in the chamber, and a series of steps of rubbing, cleaning, and drying by the apparatus of the present invention is completed.

It should be noted that the rubbing process shown in FIG. 3(B) may be performed in accordance with that described in the conventional example (see 2 in the figure). The main part of the brushing cleaning mechanism 13 according to the present invention is shown in FIG.
A brushing cloth is wrapped around the brushing roller 23 having a diameter of φ. The brushing cloth is, for example, a nylon base fabric with a thickness of about 0.7 mm, and fibers, so-called piles, about 20 μmφ in thickness and 2 mm in length are planted perpendicular to the surface of the base fabric. For example, it is best to use something with a slightly weaker pile than the pile of a rubbing cloth. As conceptually shown in Figures (B) and (C), a rubbing roller 22 and a brushing roller 23 are installed.
Place it parallel to. This allows the rubbing direction and the brushing direction to match.

On the other hand, a cleaning liquid injection pipe 33 having a large number of cleaning liquid injection ports is arranged along the brushing roller 23.
A cleaning liquid, such as IPA, a neutral detergent aqueous solution, or pure water, is sprayed as indicated by the arrow to brush and clean the substrate (not shown). Note that the cleaning liquid is not limited to those mentioned above, and other cleaning liquids may be used. It goes without saying that the cleaning liquid may also be supplied by other methods, such as by immersing the brushing roller 23 in a cleaning tank filled with the cleaning liquid. Furthermore, it goes without saying that the brushing cleaning is not limited to one stage, but may be performed in multiple stages as necessary to enhance the cleaning effect.

FIG. 3(C) conceptually shows the situation and effects of brushing cleaning. That is, under the brushing cloth wrapped around the rotating brushing roller 23 of the brushing cleaning mechanism 13 directly connected to the upstream rubbing mechanism 12 (not shown), the substrate 1 ( On top of that, for example, ITO
When a striped drive electrode 2 made of a film and an alignment film made of a rubbed polyimide resin film are carried in, the pile 230 lightly rubs the surface of the alignment film. At the same time, a cleaning liquid (not shown) is sprayed to wash away the alignment film surface. At this time, the inclination of the brushing roller 23 is the same as the inclination of the rubbing roller during rubbing, that is, both rollers are parallel to each other, and preferably, the direction of rotation of the brushing roller 23 is opposite to that of the rubbing roller. As a result, as shown in the figure, the dust 101 caught on the foreign matter 100 on the alignment film surface is removed.
has the advantage that it is very easily removed by the pile 230 of the brushing roller (the dirt 101 becomes dirt 101' and is washed away with the cleaning liquid).

After brushing and cleaning, shower cleaning and drying as described above completes a series of processing steps according to the method of the present invention, and by using this to construct a liquid crystal display panel, high display quality and yield can be achieved. can get.

It should be noted that the above-mentioned embodiments are merely examples, and other materials may be used as appropriate, such as materials used for each part, detailed process conditions, or combinations thereof, as long as they comply with the spirit of the present invention. Of course, you may use them selectively.

[0023]

Effects of the Invention As explained above, according to the present invention, foreign particles 1 that have bitten into the alignment film surface, which are difficult to remove by ultrasonic cleaning, can be removed.
00 and strongly adhered dust 101 can be easily removed by brushing. In addition, the pile of the brush is made slightly weaker and the brushing direction is parallel to the rubbing direction 200 during rubbing, so that the alignment performance due to the rubbing process is not deteriorated, so the cleaning effect is high and it is suitable for liquid crystal display devices. This greatly contributes to improving display quality and yield.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating the effects of rubbing and foreign matter.

FIG. 3 is a diagram showing an example of a conventional rubbing/cleaning device.

[Explanation of symbols]

1 is a transparent substrate, 2 is a drive electrode; 3 is an orientation coating film; 10 is a cassette, 11 is loader, 12 is a rubbing processing mechanism; 13 is a brushing cleaning mechanism; 14 is a shower cleaning machine, 15 is a dryer, 16 is an unloader, 17 is a substrate transport mechanism; 22 is a rubbing roller, 23 is a brushing roller, 33 is a cleaning liquid injection pipe; 100 is a foreign object, 101 is garbage, 230 is pile,

Claims (3)

[Claims] Claim 1: A liquid crystal display panel in which at least a driving electrode (2) and an alignment coating film (3) are laminated on a transparent substrate (1), and the surface of the alignment coating film (3) is rubbed and then cleaned. A method of manufacturing a substrate for a liquid crystal display panel, characterized in that the cleaning is brushing cleaning, and the brushing direction is parallel to the rubbing direction during the rubbing. 2. The method of manufacturing a substrate for a liquid crystal display panel according to claim 1, wherein the brushing direction of the cleaning and the rubbing direction of the rubbing are opposite to each other. 3. A brushing cleaning mechanism (13) is provided directly after the rubbing mechanism (12) for rubbing the orientation coating film (3), and the rubbing mechanism (13)
12) and the brushing roller (23) of the brushing cleaning mechanism (13) are arranged in parallel.