JPH0136085B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal cell equipped with a plurality of liquid crystal layers arranged in a stacked manner, and more specifically to a so-called liquid crystal cell equipped with a plurality of liquid crystal layers as described above. The present invention relates to a liquid crystal sealing structure in a multilayer liquid crystal cell.

In recent years, as display functions have increased, multilayer liquid crystal cells having multiple liquid crystal layers have been put into practical use.

FIG. 1 shows the structure of a liquid crystal cell having two liquid crystal layers as a typical conventional multilayer liquid crystal cell, and the connection structure of the liquid crystal cell with a typical drive circuit.

1 indicates the upper substrate, 2 indicates the middle substrate, 3 indicates the lower substrate,
Adhesive layers 4 and 5 are formed near the outer periphery of each of the substrate plates 1, 2, and 3. 7 and 8 are display electrodes (segment side electrodes), 9 and 10 are counter electrodes (common side electrodes), and 6a and 6b are liquid crystal layers. and,
To connect the liquid crystal cell to the drive circuit 13, the upper surface of the upper substrate 1 is tightened with the holding fittings 11a and 11b, and the display electrodes 7 and 8 disposed on the lower surfaces of the upper substrate 1 and the middle substrate 2 are connected. The terminals for connection with an external circuit, that is, the lead portions 7a and 8a, and the drive circuit are connected via connecting rubbers 12a and 12b, respectively. The problem here is the upper board 1 and the middle board 2.
The adhesive layer between the middle substrate 2 and the lower substrate 3, that is, the first adhesive layer 4, and the second adhesive layer 5, which is the adhesive layer between the middle substrate 2 and the lower substrate 3,
The sides on which the lead portions 8a of the display electrodes 8 disposed on the lower surface side of the display electrodes 8 are deviated from each other in plan view.

Therefore, when the upper surface of the upper substrate 1 is tightened with the presser fitting 11a, the upper substrate 1 and the middle substrate 2 are bent around the connecting rubber 12a as shown in FIG. 2, and as a result, the liquid crystal layers 6a and 6b are bent. The thickness of the liquid crystal cell becomes non-uniform, which seriously impairs the optical and electrical properties of the liquid crystal cell. In addition, when the members constituting both the adhesive layers 4 and 5 are made of brittle materials such as low-melting point glass, the force applied by the presser metal fitting 11a can be used to bond the adhesive layers 4 and 5 together. Cracks occur in the layers 4, 5 and the respective substrates 1, 2, 3, and the airtightness of the liquid crystal cell is often lost.

Therefore, as an improvement on the conventional sealing structure of the liquid crystal cell, the present applicant has filed a patent application for a sealing structure as shown in FIGS. The sealing structure according to this improved proposal will be briefly explained. FIG. 3A shows a plan view, and FIG. 3B shows a sectional view taken along line A-A' of FIG. This improvement plan is the first
A partition member 14 is disposed inside the adhesive layer 4, and the partition member 14 almost overlaps the second adhesive layer 5 in plan view near the side of the middle substrate 2 where the display electrode lead portion 8a is arranged. the first adhesive layer 4 at the position
are provided consecutively.

Now, a typical method for forming the partition member 14 according to this improved proposal is a method in which it is formed using the same member as the first adhesive layer 4. That is, when low melting point sealing glass is used as the members 4 and 14, a sealing paste made of a mixture of glass frit and organic vehicle is applied to predetermined positions of the upper substrate 1 and the middle substrate 2.
Thereafter, the first adhesive layer 4 and the partition member 14 can be formed simultaneously by overlapping both substrates 1 and 2 and firing the paste.

According to this improvement plan, the above-mentioned problems that occur when the liquid crystal cell having the conventional sealing structure is held down by the holding fitting 11a in order to connect it to the drive circuit 13 can be almost solved. Problems will occur.

That is, first of all, in the process of firing the paste, the region B surrounded by the first adhesive layer 4 and the partition member 14 is almost in a sealed state, and the organic vehicle contained in the paste is heated to about 300°C. There is insufficient supply of oxygen necessary to heat the material to a certain degree and burn it out. Therefore, even if the temperature is further increased to the melting temperature of the glass frit, the organic beagles remaining in the glass frit have a negative effect on the glass melting of the glass frit, so that the first adhesive layer 4 and the partition member 14 are Sufficient chemical stability, mechanical strength, etc. cannot be obtained.

Second, the first adhesive layer 4 and the partition member 14
Region B surrounded by is completely sealed when the glass frit melts. Therefore, the region B, which is sealed at the melting temperature of the glass frit, which is generally about 450 to 500°C,
After cooling both the substrates 1 and 2, the pressure is reduced compared to the display area C, and the gap between the substrates 1 and 2 in the area B not only becomes smaller than the gap between the substrates in the display area C, but also As a result, the gap between the substrates near where the partition member 14 is formed in the display area C also becomes smaller.
The gap between the substrates becomes sloped, making it difficult to form a constant gap between the substrates necessary for the liquid crystal cell.

On the other hand, even in the case where an organic adhesive such as an epoxy resin adhesive is used as the member constituting the partition member 14 and the first adhesive layer 4 in this improved proposal, it is almost the same as in the case of the low melting point sealing glass. A similar problem will occur.

The purpose of the present invention is to further perfect the above-mentioned conventional improvements, and the present invention will be described in detail along with examples.

FIG. 4 shows an embodiment of the present invention, in which A is a plan view and B is a sectional view taken along line D-D' of A.

In this example, partition members 15 are disposed intermittently along the inside of the first adhesive layer 4, that is, in addition to having openings 16. It is provided at a position near the side where the adhesive layer 5 is arranged and substantially overlaps the second adhesive layer 5 in a plane. The method for forming the partition member 15 may be to use the same member as in the first adhesive method 4 and to perform it simultaneously with the formation of the first adhesive layer 4. That is,
As in the case of the conventional example, low melting point sealing glass or epoxy resin adhesive is simultaneously applied as the members 4 and 15 to one or both of the upper substrate 1 and the middle substrate 2 by means such as screen printing, and The same members as the members 4 and 15 are applied to one or both of the middle substrate 2 and the lower substrate 3. Thereafter, the respective substrates 1, 2, and 3 are stacked and bonded to form the first adhesive layer 4, the second adhesive layer 5, and the partition member 15 at the same time.

FIG. 5A shows another embodiment, in which A is a plan view and B is a sectional view taken along line E-E' of A.

In this embodiment, the first adhesive layer 4 is disposed at a position that substantially overlaps the second adhesive layer 5 in a plane, and the partition member 15
This is an example in which the opening 17 is arranged along the outer periphery of both substrates 1 and 2 on the side of the middle substrate 2 on which the display electrode lead portion 8a is arranged. Note that the partition member 15 may be formed by the same means as in the previous embodiment. According to this embodiment, the finishing member 15, which is unnecessary for the display of the liquid crystal cell, and the first
It is not necessary to fill the area surrounded by the adhesive layer 4 with an expensive liquid crystal material, so the structure can be said to be extremely economical.

FIG. 6 shows still another embodiment, in which FIG.

In this embodiment, display electrode lead portions 7a, 7b, 8a, and
This is an example where 8b is arranged on two sides of both substrates 1 and 2, respectively. Therefore, in this embodiment, the partition members 15a and 15b are also arranged on two sides, and 18a and 18b are openings provided respectively. That is, the first adhesive layer 4 is formed at a position that substantially overlaps the second adhesive layer 5 in a plane, and the partition members 15a and 15b are connected to the display electrodes 8a and 8 of the middle substrate 2.
This is an example in which they are arranged intermittently on the outer periphery of each side.

As described above, the present invention makes it possible to increase the sealing strength of a liquid crystal cell by forming a partition member that does not form a sealed area between it and the adhesive layer. It is possible to completely prevent deformation of the liquid crystal cell while maintaining the connection. Furthermore, the partition member provides an extremely inexpensive sealing structure that can be formed without increasing the number of steps required for conventional substrate sealing.

In the above embodiments, the case of a liquid crystal cell having two liquid crystal layers was taken as an example, but the effect of the present invention is even greater when the cell has three or more liquid crystal layers.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the structure of a conventional liquid crystal cell having two liquid crystal layers and the connection structure with a drive circuit. FIG. 2 is a cross-sectional view showing the sealing structure of a conventional liquid crystal cell. FIGS. 3A and 3B are a plan view and a sectional view showing a conventional sealing structure. Figure 4 A, B, Figure 5 A, B,
FIGS. 6A and 6B are a plan view and a sectional view, respectively, showing an embodiment of the present invention. 1, 2, 3...substrate, 4, 5...adhesive layer, 6...
...Liquid crystal layer, 7a, 7b, 8a, 8b... Display electrode lead part, 13, 15... Partition member, 16, 1
7, 18a, 18b...openings.

Claims (1)

[Scope of Claims] 1. An upper substrate, a middle substrate, and a lower substrate are stacked and arranged in order of decreasing size, and the upper substrate and the middle substrate are bonded at the periphery of the overlap using a first adhesive layer, In a liquid crystal cell in which a middle substrate and a lower substrate are bonded together at the periphery of their overlap using a second adhesive layer, and a liquid crystal layer is held between the respective substrates, the first bonding layer is bonded on at least one side. 2nd layer
A liquid crystal cell characterized in that a partition member is disposed outside the adhesive layer and has an opening at a position inside the first adhesive layer and substantially overlaps with the second adhesive layer. 2 Arrange the upper substrate, middle substrate, and lower substrate in the order of decreasing size, adhere the upper substrate and the middle substrate with the first adhesive layer, and bond the middle substrate and the lower substrate with the second adhesive layer. In the liquid crystal cell in which the first adhesive layer is formed at a position substantially overlapping with the second adhesive layer, the first adhesive layer is formed at a position substantially overlapping with the second adhesive layer, and the first adhesive layer is formed at a position substantially overlapping with the second adhesive layer. A liquid crystal cell characterized in that a partition member having an opening is formed outside the first adhesive layer. 3. Claim 1, characterized in that the partition member is made of the same member as the adhesive member constituting the adhesive layer, and also has the function of bonding the substrate.
The liquid crystal cell according to item 1 or 2.