JPS6125123A - Manufacture of liquid-crystal display panel - Google Patents

Abstract

PURPOSE:To prevent liquid crystal from contacting a seal material directly by providing a couple of electrode-attached plastic film substrates at least one of which is transparent so that their electrode surface sides face each other, sealing the peripheral part of the substrates and then charging a liquid crystal compound with which spacers are mixed and sealing the periphery completely. CONSTITUTION:Oriented films 14 and 15 are formed on the plastic film substrates 12 and 13 having a couple of electrodes 10 and 11, and three parts 16, 17, and 18 of the peripheral part are sealed so that the electrode surface sides each other, constituting a bag-shaped cell. The liquid crystal compound 20 with which spacers of specific size (e.g. 7mum) are mixed so that a specific gap is held in the bag is charged in the bag-shaped cell, which is evacuated by a vacuum bagging machine until the liquid crystal layer is 7mum thick to discharge an excessive liquid crystal compound; and the bag is sealed by press-fixing a cell opening part 19 thermally. Consequently, the gap is held within 7+ or -0.2mum without any process of spacer dispersion, and liquid crystal never contacts the seal material directly.

Description

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

Structure of the conventional example and its problems As shown in FIG. 1, the conventional manufacturing method of the liquid crystal display panel is as follows: At least one of the substrates 2 has a transparent electrode 1, and the substrate 4 with the electrodes 3 has the electrodes 1 and 3 on each side. After forming alignment films 6, 6 on the periphery thereof, applying a sealing material 7 mixed with a baser and pasting them together to form a cell, the cell is placed in a vacuum device.
After sufficiently reducing the pressure from the outside of the cell through the injection port to the inside of the cell, the injection port is immersed in the liquid crystal composition, and while the inside of the vacuum device is returned to atmospheric pressure, the liquid crystal composition is injected into the cell and the injection port is closed. The method used was to seal it.

However, in order to inject the liquid crystal composition without leaving any bubbles inside the cell, the pressure must be sufficiently reduced to the inside of the cell. For this reason, the process of injecting the liquid crystal composition took a lot of time. On the other hand, when the area of the cell becomes large, not only is it time consuming, but also there is a problem that the gap between the center part and the surrounding part of the cell becomes non-uniform. Particularly when the substrate is a plastic film, the upper and lower plastic film substrates are in close contact with each other, making it very difficult to inject the liquid crystal composition. In addition, even in a panel configured by adding a step of dispersing spacers 9 over the entire surface of the substrate between the step of applying sealant 8 and the step of bonding as shown in Fig. 2, not only the number of steps increases, but also , required large-scale equipment to uniformly disperse the spacers, resulting in a significant increase in costs. In addition, after dispersing the spacers, until the two substrates are bonded together, great care must be taken to ensure that dust does not easily get mixed in and that the spacers do not move and become uneven, which reduces work efficiency. Purpose of the present invention is to eliminate such conventional drawbacks, and to provide an excellent liquid crystal display panel of high quality and high yield using a new liquid crystal injection method that can inject a liquid crystal composition with a simple structure. It provides a manufacturing method.

Structure of the Invention The method for manufacturing a liquid crystal display panel of the present invention includes a pair of electrode-attached plastic film substrates, at least one of which has a transparent electrode, with the electrode surfaces facing each other, and three sides of the periphery of the substrates are sealed. This is a liquid crystal display panel in which a spacer and a liquid crystal composition are then added, the liquid crystal layer is pressed against the substrate until it reaches a predetermined thickness, and the opening is then sealed. This allows a liquid crystal composition to be injected into the cell.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, as shown in FIG.
, 16i are formed, and the peripheral portions 16, 17 and 18 are sealed on three sides with the electrode surfaces facing each other to form a bag-like cell. Next, liquid crystal composition 2 is mixed with a spacer of a predetermined size (for example, 7 μm) to maintain a constant gap inside the bag.
0 into the bag-like cell with a syringe or the like, the pressure is reduced using a vacuum packaging machine until the liquid crystal layer has a thickness of 7 μm, excess liquid crystal composition is removed, and then the cell opening 1e is heated. Seal by crimping. In this way, the gap can be maintained within 7.0±0.2 μ without the need for a spacer dispersion process. In addition, the reliability is high because the liquid crystal does not come into direct contact with the sealing material, and it also requires a liquid crystal container for liquid crystal injection, a high vacuum device to create a sufficient vacuum state inside the panel, and the necessary treatment. Not only does it eliminate the need for tools, such as mechanical parts for raising and lowering the liquid crystal cell, but it also significantly reduces panel manufacturing time and significantly improves work efficiency.

Further, after forming the bag-shaped cells, a predetermined amount (for example, 7μ
After blowing in and dispersing the spacer (m), put the liquid crystal composition into the bag-shaped cell using a syringe or the like, then apply a uniform load with a weight until the liquid crystal layer reaches 71 Im, and seal the opening with adhesive. Even with the method of sealing, there is no need for complicated equipment to uniformly distribute the spacers, and there is no need to worry about dirt getting in, which reduces work efficiency. In addition to being able to prevent this, as in the previous example, the gap is equalized and no equipment or jigs are required for liquid crystal injection, resulting in a significant cost reduction compared to the conventional method and a significant improvement in work efficiency. I was able to do something.

Effects of the Invention As described above, the present invention provides a method for injecting a liquid crystal composition into a cell sealed on three sides, after putting the liquid crystal composition mixed with spacers, or by dispersing the spacers. After the liquid crystal layer is placed in the liquid crystal layer, it is sealed by pressure until it reaches a predetermined thickness, and it requires equipment such as large spacer dispersion equipment and high vacuum equipment to make the panel gap uniform.) Since no jigs or tools are required, costs can be significantly reduced. In addition, even when using a plastic film substrate, the liquid crystal composition can be easily injected in a short time without going through many steps as in the past, which greatly helps improve workability. This eliminates defects such as air bubbles remaining in the cell due to insufficient or excessive vacuum, and poor appearance due to uneven gaps, which greatly contributes to improving the quality and yield of the LCD panel itself. This is extremely advantageous in practice.

[Brief explanation of the drawing]

Figure 1 a1 Figure 1 is a plan view and cross-sectional view of a conventional liquid crystal display panel, Figure 2 is a cross-sectional view of a conventional liquid crystal display panel in which spacers are dispersed, Figure 3 a1 Figure 3 is a main 1 is a plan view and a cross-sectional view of an embodiment of a liquid crystal display panel according to the method of the invention. 1...Transparent electrode, 2, 4...Substrate, 3
... Electrode, 5.6 ... Alignment film, 7...
... Seal material, 8 ... Inlet, 9 ...
... Spacer ~, 10.11 ... Electrode, 12,
．． 13...Plastic film substrate, 14°16...Alignment film, 16,17.18...
・Substrate peripheral sealing section, 19... Opening section, 20...
...Liquid crystal composition. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Cause (phantom Cb) Figure 3 ((L) (b)

Claims (6)

[Claims] (1) A pair of plastic film substrates with electrodes, at least one of which has a transparent electrode, are arranged so that their respective electrode surfaces face each other, and after sealing three sides of the periphery of the substrates, a liquid crystal composition mixed with a spacer is placed therein; A method for manufacturing a liquid crystal display panel, characterized in that the openings are sealed after the liquid crystal layer is made to a predetermined thickness. (2) The method for manufacturing a liquid crystal display panel according to claim 1, characterized in that a liquid crystal composition is placed between the two substrates sealed on three sides after dispersing spacers. (3) The method for manufacturing a liquid crystal display panel according to claim 1, wherein after adding the spacer and the liquid crystal composition, the liquid crystal layer is made to have a predetermined thickness under reduced pressure. (4) The method for manufacturing a liquid crystal display panel according to claim 1, wherein the liquid crystal layer is made to have a predetermined thickness by applying pressure after adding the spacer and the liquid crystal composition. (5) The method for manufacturing a liquid crystal display panel according to claim 1, wherein after adding the spacer and the liquid crystal composition, the liquid crystal layer is made to a predetermined thickness and the opening is sealed by thermocompression bonding. (6) The method for manufacturing a liquid crystal display panel according to claim 1, wherein after adding the spacer and the liquid crystal composition, the liquid crystal layer is made to a predetermined thickness and the opening is sealed with an adhesive material.