JPS63155021A - Production of liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain a cell of high precision by pressing a seal with an annular elastic body from above and pressing a screen part other than the part of the seal with an elastic body different from said elastic body in rigidity per unit area. CONSTITUTION:An elastic body 21 consisting of silicone rubber or the like is provided with many projections 22 like a frog to uniformly disperse the pressing force. An annular elastic body 20 placed on a seal 17 of a cell 19 is fitted to a holding groove 24 provided on a holding member 23 of this elastic body to press the cell 19 from above the seal 17. A load 25 is applied by the spring method or the weight method. The elastic body provided with many projections 22 is arranged in the screen of the cell and takes a charge of load together with the elastic body 20 on the seal 17 to apply the pressure to the cell, and in this state, the seal is hardened. Thus, the cell of high precision whose thickness is regular uniform is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly to a method for bonding two substrates together.

Conventional technology As a method for manufacturing a liquid crystal display device in which liquid crystal is sealed between two electrode-attached substrates, there is a method for bonding two substrates together.
A common method is to stack a substrate coated with an adhesive in a seal pattern with another substrate via a spacer, and heat and cure the seal adhesive while pressing the two substrates with a weight.

FIG. 6 shows an explanatory diagram of such a conventional bonding method, in which two electrode-attached substrates 1 and one of them are coated with a sealing adhesive 3 containing a spacer material, and then stacked with a spacer 4 interposed therebetween. Stack the combined cells 6 alternately with sheets 6,
A load 8 is applied via a suppressing plate 7 using a spring or a weight. In this state, the entire temperature is raised to heat and harden the seal adhesive 3. Such a method causes variations in the uniformity of the pressure applied to the cells 5, and therefore there is a limit to the thickness accuracy of the cell gap. This is a particularly serious drawback in the case of large-area liquid crystal display devices or active matrix liquid crystal display devices in which the substrate undergoes a multilayer thin film process and has a large warpage. 7th
Figure a shows an example of a conventional pressurizing method that improves this point. For example, instead of using the heat-resistant polyimide sheet 6, a load 8 is applied to the cell 6 with a suppression plate 7 via a silicone rubber block 9. . Even in such an example in which the uniformity of the pressure applied to the cell is improved, the pressure distribution 10 shown in FIG. When the adhesive is highly adhesive, the cell gap can only be narrowed to a predetermined gap determined by the spacer material mixed in the sealing adhesive, making it difficult to obtain uniformity of the gap.

Problems to be Solved by the Invention In contrast to the conventional technology, the present invention provides a new method for bonding two electrode-attached substrates, and realizes a highly accurate cell with less variation and non-uniformity in cell thickness. Therefore, it is an object of the present invention to provide a manufacturing method for realizing a liquid crystal display device having high quality image quality performance with high contrast and little unevenness in density. Although the drawbacks of conventional bonding methods are as described above, the present invention is particularly effective in manufacturing methods for simple matrix or active matrix liquid crystal display devices for displaying large-area, high-precision single images. In devices such as this, the key to achieving high image quality is whether or not it is possible to achieve high gap accuracy, and it has not been possible to obtain satisfactory display performance using conventional bonding methods. The present invention particularly focuses on the suppression conditions of the seal located around the cell, and on the inside of the screen of the cell in order to match two electrode-attached substrates with warpage and ridges with high precision along the spacer material. The purpose of this method is to solve these problems based on the technical idea that there are independent optimal suppression conditions for each suppression condition.

Means for Solving the Problems The present invention adopts the following configuration in order to solve the above problems. That is, in a method of manufacturing a liquid crystal display device in which liquid crystal is sealed between two substrates with electrodes, the steps include applying a sole adhesive containing a spacer material to one of the substrates, and separating the two substrates with electrodes. and a step of curing the seal while pressing the stacked cells, and a ring-shaped elastic body that presses on the seal as means for pressing and holding the cells, and The elastic body has a different rigidity per unit area from the elastic body, and has an elastic body that presses parts other than the seal of the cell, a holding member that holds these elastic bodies, and a means for holding and holding the cell in a suppressed state. However, it is characterized in that pressure is applied to the cell using these elastic bodies.

Function As described above, as a method of pressurizing two electrode-attached substrates, the seal is pressed with an annular elastic body, and the screen area other than the seal is pressed with an elastic body that has a different rigidity per unit area from this elastic body. By doing so, both suppression conditions can be independently set to optimal conditions. When aligning two electrode-attached substrates with complicated warps and undulations to a highly accurate gap along a spacer, it is possible to apply a uniform pressure by selecting a soft stiffness of the latter elastic body.

In particular, uniform surface pressure can be achieved by using a shape with a large number of Kenzan-type protrusions as an elastic body that presses the inside of the screen.

Example Next, the present invention will be described in detail according to examples of the present invention.

FIGS. 5a, b, and C show a part of the method for manufacturing an active matrix type liquid crystal display device for color image display according to the present invention, in which two electrode-attached substrates (a and b) and these are combined. A liquid crystal cell C is shown. Figure 5a
As shown in FIG. 1, thin film transistor elements serving as pixel elements for image display and switching elements are fabricated on the surface of one electrode-equipped substrate 11 by vapor deposition and photofabrication techniques to form a screen 12. A large number of extraction electrodes 13 for scanning image signals and signals are formed around the screen, and an alignment film 4 is formed covering the screen.
is coated. As shown in FIG. 5, on the electrode-attached substrate 15 on which the other color filter is formed, an alignment film is also applied covering the entire surface of the transparent electrode, and a sealing adhesive containing a spacer material is applied around this. It is applied in the form of a seal pattern with a part of it open as the injection port 18. These two electrode-attached substrates 11 and 16 are placed one on top of the other with the alignment film on the inside via a spacer to form a liquid crystal cell 19 shown in FIG. 5C.

FIG. 1 shows a state in which a cell 19 according to an embodiment of the present invention is bonded together and pressed. FIG. 3 shows a plan view a and a side sectional view of the annular elastic body 20 for suppressing the seal used in this bonding pressure, and FIG. A plan view a and a side cross-sectional view of the elastic body 21 are shown. The elastic body 21 is provided with a large number of protrusions 22 in the shape of a protrusion 22, and has a structure aimed at uniformly distributing the pressing force. 1st
As shown in the figure, an annular elastic body 2o located above the seal 17 of the cell 19 fits into a holding groove 24 provided in a holding member 23 of this elastic body, and presses the cell 19 on the seal. . The load 25 is applied by a spring type or a weight type. An elastic body with a large number of protrusions 22 is placed inside the screen of the cell, and applies pressure to the cell by sharing the load with the elastic body 2o on the seal. In this state, the seal is cured, liquid crystal is injected through the injection port in a vacuum, the seal is sealed, and polarizing plates are attached to the front and back surfaces to form a completed liquid crystal cell.

Here, as the material for the annular elastic body 2o for seal suppression and the elastic body 21 for pressing inside the screen, non-contact rubber is good in terms of heat resistance. When the seal was heated and cured with a weight load of 15 kq in the bonded and pressurized state of the liquid crystal cell shown in FIG. 1, the cell gap accuracy after injection of the liquid crystal was within 2 μm.

FIG. 2 shows a state in which a cell 19 is laminated and pressed, showing a second embodiment of the present invention. The elastic body 26 includes an annular elastic body 20 that presses on the seal and a number of protrusions 2 that press the center of the screen.
It is integrally molded from an elastic body portion with 2 parts, and is held and fixed by a holding member 23. These rigidity ratios are appropriately selected so that the pressure conditions for the seal portion and the pressure conditions for the center of the screen are balanced. In this way, when the load conditions as manufacturing conditions are determined, it is more convenient to use these elastic bodies as one piece.

Effects of the Invention As described above, according to the manufacturing method of the present invention, it is possible to apply a uniform and stable pressing force with an ideal load distribution to the sealing part and the inside of the screen when bonding cells, and as a result, the cell thickness can be reduced. High-precision cells with very little variation and non-uniformity can be easily obtained, and liquid crystal display devices with excellent display performance can be provided, which is of great industrial value.

[Brief explanation of the drawing]

FIG. 1 is an assembled sectional view of a liquid crystal display device according to an embodiment of the method for manufacturing a liquid crystal display device of the present invention, and FIG.
FIG. 3 is an assembled sectional view of a liquid crystal display device according to an embodiment of the present invention; FIG. 3 is a plan view and a side sectional view of an annular elastic body according to the present invention;
The figures are a plan view and a side sectional view of an elastic body with projections according to the present invention, FIG. 5 is a perspective view showing a method of manufacturing a liquid crystal display device according to an embodiment of the present invention, and FIGS. 6 and 7 are FIG. 2 is an assembled cross-sectional view of a conventional method for manufacturing a liquid crystal display device. 11...Substrate with electrode (array substrate with TFT),
15... Substrate with electrode (color filter substrate), 19
...Liquid crystal cell, 17...Seal adhesive, 2
0... Annular elastic body, 21... Elastic body with projections, 23... Holding member. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Do65 Kotoshini 1 A (Figure 3 and b) Figure 4 and Otsu) △ Force) Figure 5 and C)

Claims (4)

[Claims] (1) A method for manufacturing a liquid crystal display device in which liquid crystal is sealed between two electrode-attached substrates with a seal, including the steps of: applying a sealing adhesive containing a spacer material to one of the substrates;
The process includes a step of stacking two electrode-equipped substrates via a spacer means, and a step of hardening a seal while pressing the stacked cells. The elastic body has a different rigidity per unit area, and the elastic body presses the area other than the seal of the cell, the holding member holds these elastic bodies, and the cell is held in a pressed state. A method for manufacturing a liquid crystal display device, comprising holding means and applying pressure to a cell using these elastic bodies. (2) The method for manufacturing a liquid crystal display device according to claim 1, wherein the elastic body that presses a portion of the cell other than the seal is constituted by a large number of protrusions of the Tsurugi-san type. (3) Claim 1 in which the elastic body is silicone rubber
A method for manufacturing a liquid crystal display device according to section 1. (4) The seal adhesive is a thermosetting adhesive, and the cell is pressed by a ring-shaped silicone rubber that presses on the seal and a number of Tsurugi-style protrusions that press on parts of the cell other than the seal. Claim 1, characterized in that the seal is cured by heating while being held in that state.
A method for manufacturing a liquid crystal display device according to section 1.