JPH0118403B2 - - Google Patents

Description

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

In recent years, small-sized liquid crystal display elements have come to be used in large quantities in wristwatches, desktop computers, etc., and multiple sets of transparent electrodes are formed on a large glass substrate. A so-called multi-crystal manufacturing method has been known in which a plurality of liquid crystal cells are formed in between, and then the glass substrate is cut and divided to obtain individual liquid crystal cells.

To specifically explain an example of a method for manufacturing such a liquid crystal cell, first, in FIG. 1, a relatively large glass substrate 1 has four lower substrate parts 2, 3, ... 5, in an upper row thereof. The next stage row consists of four upper board parts 6, 7, . . . 9, and the next stage row has four lower board parts 10, and so on. The one-dot chain line shown at the boundary of each substrate part is a cutting line showing the part where the glass substrate 1 is to be separated in a later step. The upper substrate portion 6 has transparent segment electrodes 6a and terminals 6b, 6c forming a Japanese character shape.
are formed, and these are connected to each other by connecting wires (not shown). segment electrode 6a,
The terminals 6b, 6c and connection lines are made of a transparent conductive film and are formed by photo-etching or the like. Note that segment electrodes, terminals, and connection lines are formed in exactly the same pattern on the other upper substrates 7, 8, 9, . . . . On the lower substrate portion 2, a common electrode 2a and a connection line (not shown) connected to the common electrode 2a are formed using a transparent conductive film by photo-etching or the like.
Note that the other lower substrates 3, 4, 5, 10, . . . are also formed in exactly the same pattern. The connection line formed on the lower substrate part functions as a circuit to connect the common electrode to the terminal when the lower substrate part faces the upper substrate part of another glass substrate to form a liquid crystal cell in a later process. .

On the glass substrate 1 on which each electrode of the transparent conductive film is formed, a protective film is further formed using a transparent inorganic film such as SiO ₂ or an organic film such as polyimide or PVA. In order to achieve orientation, for example, SiO or the like is formed by oblique evaporation, or orientation control treatment is performed by rubbing or the like.

On the other hand, as shown in FIG.
There is a glass substrate 11 of almost the same size as , and the upper row has four upper substrate parts 12, 13,...15,
The next stage row has four lower substrate parts 16, 17,...1.
9. Furthermore, in the next stage row, there are four lower substrate parts 20,
It is composed of a large number of substrate parts, such as... The one-dot chain line shown at the boundary of each substrate part is a cutting line showing the part where the glass substrate 11 is to be separated in a later step. Each upper substrate portion of this glass substrate 11 is formed with a transparent conductive film having almost the same pattern as each upper substrate portion of the glass substrate 1 described above, but the only difference is that the upper substrate portion is turned over. ,
When facing each lower substrate portion of the glass substrate 1, the common electrode of the lower substrate portion and the segment electrode of the upper substrate are reversely patterned so as to overlap. Further, each lower substrate portion of the glass substrate 11 is also formed with a transparent conductive film having almost the same pattern as each lower substrate portion of the glass substrate 1 described above. A pattern is formed such that the segment electrodes of the upper substrate portion and the common electrode of the lower substrate overlap when facing each upper substrate portion.

Then, on the glass substrate 11 on which each electrode of the transparent conductive film is formed, an inorganic or organic transparent protective film is formed similarly to the glass substrate 1 described above, and this protective film is subjected to orientation control treatment. .

Next, as shown in FIG. 3, multiple sets of sealing adhesives 21, 22, . . . 25, . Form each. In this case, each of the adhesives 21, 22, . . . , 25, . . . has an opening for filling the liquid crystal. Although not shown, an adhesive is similarly formed on each lower substrate portion of the glass substrate 11. Note that the adhesive in this case does not necessarily have to be formed separately on the glass substrates 1 and 11; for example, the adhesive on the glass substrate 1
An adhesive may be formed on each lower substrate portion and each upper substrate portion.

Next, as shown in FIG. 4, the glass substrate 11 is turned over and placed on the glass substrate 1. On this occasion,
The common electrodes on each lower substrate portion of the glass substrate 1 and the segment electrodes on each upper substrate portion of the glass substrate 11 face each other, and at the same time, the segment electrodes on each upper substrate portion of the glass substrate 1 and the segment electrodes on each lower substrate portion of the glass substrate 11 face each other. The common electrodes are aligned so that they face each other. Then, the combination of the glass substrates 1 and 11 is heat-treated to harden or heat-seal the adhesives 21, 22, . . . , 25, .

Then, each of the glass substrates 1 and 11 is scratched along the above-mentioned cutting lines by, for example, glass cutting, and then pressure is applied to the combination of the glass substrates 1 and 11 to form an upper substrate portion. The cell unit surrounded by the lower substrate portion and adhesive is separated. Then, a liquid crystal is sealed in each cell through an adhesive opening, and a liquid crystal cell is formed by sealing the opening with another adhesive, solder, or the like.

However, in such a method of manufacturing a liquid crystal cell, when scratching the glass substrates 1 and 11 along the cutting line by, for example, cutting the glass, as shown in FIG. When the glass substrate is divided by applying pressure after making the above-mentioned scratches, there may be cases where the parts A and B are chipped, respectively. A diagonal crack portion C as shown in the figure occurred. As a result, the liquid crystal cells located at the peripheral portions of each glass substrate 1 and 11 have a disadvantage in that the dimensional accuracy is extremely poor compared to the liquid crystal cells located at other portions.

Therefore, an object of the present invention is to provide a method of manufacturing a liquid crystal cell that improves the dimensional accuracy of each liquid crystal cell and thereby improves the yield.

Hereinafter, this invention will be explained in detail using Examples.

FIGS. 7a, b, and c are explanatory diagrams showing an embodiment of the method for manufacturing a liquid crystal cell according to the present invention. The same reference numerals as in FIG. 3 indicate the same materials. 3, each of the glass substrates 1 and 11 has a width on its four sides that is at least 2 to 4 times the thickness t of the glass substrates 1 and 11, preferably at least 6 times the thickness t of the glass substrates 1 and 11. End portions 1a and 11a are formed, and an upper substrate portion and a lower substrate portion as shown in FIGS. 1 and 2 are formed on the glass substrates 1 and 11 within these end portions 1a and 11a. The cut points at the boundaries of the respective substrate portions of each of the glass substrates 1 and 11 extend as they are to the ends 1a and 11a.
Two glass substrates 1 and 11 and adhesives 21 and 2 interposed between each glass substrate 1 and 11
2, . . . , 25, . . . by cutting a glass, etc., along the cut points, and then applying pressure to the end portions 1a and 11a. At the same time, each cell is separated. Then, a liquid crystal display element is formed by filling each cell with liquid crystal through the openings of the adhesives 21, 22, . . . 25, . . . and sealing the openings with another adhesive or solder.

By doing this, the liquid crystal cells to be separated, especially those located around the glass substrates 1 and 11, are free from the above-mentioned chipping or diagonal cracking at the cut locations. It disappears. The reason for this will be explained below. In general, as shown in Figure 8, glass substrates are found to have a portion α where compressive strain occurs on the outside of the glass substrate and a portion β where tension strain occurs on the inside. Ta.
The portion α where compressive strain occurs is formed inward, especially at the periphery of the glass substrate, and its formation area is equal to the thickness t of the glass substrate at the periphery.
It spans 2 to 4 times the length and 2 to 4 tons of width. For this reason, when the upper or lower substrate of the liquid crystal cell is positioned around the periphery of the glass substrate as in the past, compressive strain occurs when a scratch is formed by cutting the glass, for example. Due to the influence of the part α, chipped parts occur at the beginning and end of the cut, and when the glass substrate is divided along the scratches by applying pressure, diagonal cracks occur at the same places. do. Therefore, as in the embodiment of the present invention, the thickness of the glass substrates 1 and 11 is adjusted in advance at the portion where the portion α where compressive strain occurs is formed around the glass substrates 1 and 11. By forming end portions 1a and 11a having a length of 2 to 4 times t and a width of 2 to 4 t or more, and forming a liquid crystal cell within these end portions 1a and 11a, chipping can be avoided. Alternatively, the location where the diagonal crack occurs is at the end 1.
a and 11a, and since these ends 1a and 11a are removed,
The liquid crystal cell is free from chipping or diagonal cracking, and its dimensional accuracy is improved. Therefore, the manufacturing yield becomes extremely high.

When the effect of the example was investigated by experiment, the 9th
The graph shown in the figure was obtained. In the figure, the horizontal axis represents the diagonal crack size (mm), and the vertical axis represents the cumulative frequency (%). The straight line connecting the O's indicates the cumulative frequency for the diagonal crack size of the liquid crystal cell obtained by the method of this example, and the straight line connecting the x's indicates the cumulative frequency for the diagonal crack size of the liquid crystal cell obtained by the conventional method. It shows. As can be seen from the graph, if the average diagonal crack size is μ and the standard deviation is σ, the maximum value of the diagonal crack size when considering a distribution in the range μ ± 3σ is 0.45 mm using the conventional method.
On the other hand, in the method of this embodiment, the thickness is 0.2 mm, so very good results can be obtained.

As described above, according to the method for manufacturing a liquid crystal cell according to the present invention, it is possible to improve the dimensional accuracy of each liquid crystal cell, thereby improving the yield.

Note that the same effect can be achieved even if an organic adhesive such as epoxy or an inorganic adhesive such as fritted glass is used as the adhesive used above.

[Brief explanation of drawings]

1 to 4 are explanatory diagrams showing an example of a conventional method for manufacturing a liquid crystal cell, FIGS. 5 and 6 are explanatory diagrams showing drawbacks of the conventional method for manufacturing a liquid crystal cell, and FIG. 7 is an explanatory diagram showing an example of the conventional method for manufacturing a liquid crystal cell. FIG. 8 is an explanatory diagram showing an example of the method for manufacturing a liquid crystal cell according to the present invention; FIG. 9 is a diagram for explaining the effects of the method for manufacturing a liquid crystal cell according to the present invention;
The figure is a graph for explaining the effects of the method for manufacturing a liquid crystal cell according to the present invention. 1, 11... Glass substrate, 1a, 11a... End part,
2, 3, 5...Lower substrate part, 6, 7,...9,...Upper substrate part, 21, 22,...25,...Adhesive.

Claims (1)

[Claims] 1. Two glass substrates on which transparent electrodes have been formed are placed facing each other so that these transparent electrodes face each other, and are bonded together via multiple sets of adhesive layers. A cut is made in the glass substrate for cutting, and the glass substrate In a method for manufacturing a liquid crystal cell in which a plurality of liquid crystal cells are obtained by cutting and dividing a glass substrate, each glass substrate has an end portion on its side that is cut off during cutting and dividing,
This edge has a width that allows the cutting line to be located inside the compressive strain area that occurs on the side of each glass substrate, and this edge is defined as the beginning or end of the cut for cutting. A method for manufacturing a liquid crystal cell, characterized by: