JPS6039208B2 - Manufacturing method of liquid crystal display element - Google Patents

Description

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

Liquid crystal display elements have been put into practical use as display parts for electronic watches, calculators, etc., and inexpensive mass production technology is currently required. In such a method, a liquid crystal display element is manufactured by forming a plurality of electrode patterns corresponding to the desired display pattern on a pair of substrates, assembling the electrode patterns, and then dividing the electrode patterns into individual display cells. A method can be considered,
The present invention relates to such a manufacturing method, in particular to the step of dividing into individual cells. In the case of such a manufacturing method, the conventional 1
Compared to manufacturing methods that assemble each piece one by one, efficiency increases and costs can be reduced. The manufacturing method will be briefly explained below. First, an electrode pattern corresponding to a desired display pattern is formed on a pair of glass substrates as shown in FIG.

FIG. 1 shows a diagram based on the assumption that 12 devices that display three and a half digit numbers will be made at the same time. A transparent conductive film such as tin oxide or indium oxide is used for the electrode. In the case of the so-called DSM method, one side may be a metal film such as aluminum. After surface treatment for liquid crystal molecule orientation is performed on the surfaces of the pair of substrates, a sealant for sealing the periphery is formed on at least one of the substrates by a method such as printing, and the substrates are assembled and integrated. Such a process is no different from the conventional method. The only difference is that in the conventional method, multiple items are processed at the same time, whereas in the present method, multiple items are processed at the same time. Next, the liquid crystal cells are divided into individual liquid crystal cells, but this step is a new step not found in conventional manufacturing methods, and the success or failure of this manufacturing method depends on whether this step can be performed.

Conventionally, the following method has been used in this dividing process.
First, as shown in FIG. 2, a pair of substrates are assembled using a sealant, and then a cut is made at a predetermined cutting position using a glass cutter such as a diamond cutter.

Glass cutters are not limited to diamond cutters, but
The following explanation assumes that a diamond cutter is used. The cutting positions shown in Figure 1 are the cutting positions of the upper substrate, and the cutting positions of the lower substrate are It's the location. Next, after making a wound, mechanical force is applied to each cut position to divide it. However, this method did not allow for accurate division for the following reasons.

Generally, when one side of glass is scratched with a diamond cutter and mechanical force is applied to the scratched area to break it,
As shown in Figure 3b, if a strong tensile stress is applied, it breaks successfully, but even if a compressive stress is applied, as shown in Figure 3b, it does not break properly.

Therefore, for example, in Figure 2a, when trying to separate parts C, H, and G, if a tensile stress is applied to the scratch C on the upper panel, that force will conversely be applied to the scratch C on the lower board. becomes compressive stress. Therefore, in this case, even if the upper substrate is successfully broken, the lower substrate cannot be successfully broken.
Conversely, even if tensile stress is applied to the lower substrate, the upper substrate cannot be successfully broken in this case for exactly the same reason.
In order to solve this problem, the next method was to use a diamond cutter to make a scratch on the side of one of the substrates at the cutting position that would be in contact with the liquid crystal layer before assembly.

For example, in FIG.
Before assembling , , , , , , , , , , , make a scratch on the side that will be in contact with the liquid crystal layer. Then, if you make a scratch at the predetermined cutting position on the other board after assembly, the scratches on both boards will be on the same side, and you can apply tensile stress to the scratch on either board. . Therefore, cutting is successful. However, in this case a different problem arose.

In other words, once assembled successfully, it can be divided successfully as described above. However, a problem has arisen in that the pre-scratched board at the intended cutting position breaks during the assembly process. Therefore, although the yield of the dividing process increased, the yield of the preceding assembly process decreased, and the total yield did not improve. As a result of further investigation, we found the following.

The reason why parts break at the intended cutting positions during the assembly process is because all the intended cutting positions are scratched, and most items that are damaged only in a certain direction will break during handling. Nothing happens. For example, in FIG. 1, the vertical direction is the Y direction, and the horizontal direction is the X direction. Therefore,
口, I', 口' are the cutting positions in the Y direction; At this time,
As mentioned above, if you enter ``Yu'' in advance in A', 口' in the
It will break during the assembly process. However, for example, in the Y direction,
Items with scratches only on G, C, R, and R are unlikely to break during handling during the assembly process. The same applies to those with scratches only in the X direction. Of course, it goes without saying that if a piece has been previously scratched in only one direction, it will not break properly when it is divided in the direction in which the scratch was not made.

Based on the above findings, the present invention provides a method that prevents splitting at the intended dividing position during the assembly process and allows easy division during the dividing process.

That is, in the present invention, before attaching a pair of substrates together using a sealant, one substrate is scratched with a diamond cutter at the dividing position in the X direction, and the other substrate is scratched with a diamond cutter at the dividing position in the Y direction. The method is to inflict damage. To explain based on FIG. 1, for example, the upper substrate is scratched in advance only at the opening in the Y direction on the side in contact with the liquid crystal layer.

In addition, scratches are made in advance on the lower substrate in the x direction only in the directions T, C, R, N, and R on the side that will be in contact with the liquid crystal layer.
If you assemble it after that, it will not break during assembly. Figure 2 a shows the assembled product viewed from the X direction. In Figure 2 a, at the cutting positions of F, T, C, R, N, and L, there are some holes on the surface in contact with the liquid crystal layer, that is, on the top surface. is already damaged. Therefore, if the upper substrate is subsequently scratched at cutting positions C, 2, and E, the scratches on both substrates will be on the upper surface and can be successfully broken. On the other hand, FIG. 2b shows the roughly raised substrate viewed from the Y direction. In FIG. 2b, the surface of the upper substrate in contact with the liquid crystal layer,
In other words, there are already scratches on the bottom surface.

Therefore, if you make scratches at the cut points A' and A' on the lower substrate after this, the scratches on both substrates will be on the lower surface.
In this case as well, since tensile stress can be applied to both scratches on both substrates, the cracks can be successfully broken.

Above, we have explained how to pre-scratch the upper board only in the Y direction and the lower board only in the .

As explained above, the present invention is designed so that tensile stress is applied to scratches on both the upper and lower substrates in the assembly and division processes, which are the most important processes for yield in a multi-unit manufacturing method. Using physical and engineering knowledge, we applied hot water to the top and bottom boards in the X and Y axes to prevent them from breaking during the assembly process.
This method has a special effect in that it can dramatically increase the number of defective products in the assembly and division process, compared to about 50% in the conventional method, to the point where there are almost no defective products.

[Brief explanation of drawings]

Figures 1a and 1b show the planned cutting positions of the upper and lower boards;
The opening is in the Y direction of the upper board, C, D, and E are in the X direction, A′,
The opening is in the Y direction of the lower board, and the directions are ×.
Indicates the planned cutting position in each direction. FIG. 2 shows the substrate shown in FIG. 1 in a roughly raised state, with a as seen from the x direction and b as seen from the y direction. Figure 3a shows the case where tensile stress is applied to a scratch made by a diamond cutter on the top surface of the glass, and Figure 3b
shows the case where compressive stress is applied by a diamond cutter attached to the top surface of the glass. Figure 2 Figure 3

Claims (1)

[Claims] 1 After assembling a pair of substrates on which electrodes have been formed in advance to form multiple liquid crystal display elements on the same substrate,
In a method for manufacturing a liquid crystal display element in which liquid crystal display elements are manufactured by dividing each substrate into individual parts, before assembling the pair of substrates via a sealant, only one of the predetermined dividing positions of one substrate in the X-axis direction is separated. , scratch the surface in contact with the liquid crystal layer with a glass cutter such as a diamond cutter, and cut the surface in contact with the liquid crystal layer only at the predetermined dividing positions of the other substrate in the Y-axis direction. A method of manufacturing a liquid crystal display element, which is characterized by scratching the surface with a glass cutter such as a diamond cutter.