JPS6150117A - Liquid crystal cell - Google Patents

Abstract

PURPOSE:To obtain a uniform cell thickness and to improve the circumstatial stability by providing a spacer member formed on one substate, a liquid crystal layer area whose thickness is controlled by the spacer member, and a pressure reduction space connected to the liquid crystal layer area in the gap between a pair of substrates. CONSTITUTION:The substrate 11 consists of, for example, a glass plate, and an adhesive part 12 where the substrate 11 should be adhered to the other substrate omitted in the figure is formed along the peripheral edge part of the substrate 11. A spacer member 13 is formed in the center part surrounded with the adhesive part 12 on the substrate 11, and the member 13 is patterned by photoetching after coated on the substrate 11 with a prescribed thickness. A liquid crystal layer area 14 is formed in the state divided by the member 13 and is adjacent to or connected to a pressure reduction space 16 through an interface 15. A liquid crystal is charged from a liquid crystal charging hole 17 and this charging hole 17 is sealed by a sealing agent to form the liquid crystal layer 14. Thus, a liquid crystal cell having a uniform thickness is obtained, and the circumstantial stability is improved.

Description

[Detailed Description of the Invention] "Flame" The present invention relates to the structure of a liquid crystal cell used as a display element or modulation element that utilizes electro-optic effect or thermo-optic effect. The present invention relates to a liquid crystal layer, particularly a liquid crystal cell suitable for a large area, which provides a ferroelectric liquid crystal scrap.

Traditionally, a method for regulating the thickness of the liquid crystal layer of a liquid crystal cell (hereinafter sometimes referred to as cell thickness for convenience) is to mix a capping material into the adhesive for bonding the opposing substrate. By doing so, we need to find a way to control the edges of the board, and to
Methods of dispersing gap materials are known. Using these methods, it is possible to create a cell with a size of about 6 µm or more if the area is small, but if the area is large, it is inevitable that the undulations of the substrate will result in uneven thickness. hard,
Furthermore, when attempting to create a liquid crystal cell using strong current liquid crystals, which have recently been actively developed, considering the operating characteristics of the device, the general thickness of the liquid crystal layer should be 3 mm or less. Therefore, it is completely impossible to form a cell having a uniform liquid crystal layer thickness using the method described above.

l1211 An object of the present invention is to prevent the occurrence of cell thickness unevenness due to the above-mentioned substrate waviness, etc., and to provide a liquid crystal cell with a uniform cell thickness.

Another object is to provide a liquid crystal cell with excellent environmental stability, the cell thickness of which is completely unaffected by temperature changes.

Another objective is to provide liquid crystal cells with ultra-thin layers, which cannot be achieved by the prior art.

Another object is to provide a liquid crystal cell that can achieve all of the above objects at low cost and with good productivity.

The liquid crystal cell of the present invention was developed to achieve the above-mentioned object, and is a liquid crystal cell in which liquid crystal is filled into the gap between a pair of substrates through at least one liquid crystal injection port. In the gap, a spacer member formed on at least one of the substrates, a liquid crystal layer region whose thickness is regulated by the spacer member, and a reduced pressure space communicating with the liquid crystal layer region. It is characterized by having the following.

That is, in the liquid crystal cell of the present invention, the spacer members are preferably distributed at substantially uniform intervals in the gap to be filled with liquid crystal to regulate the cell thickness, and the existence of a depressurized space communicating with the liquid crystal layer. Since the pair of substrates is brought into close contact with the spacer member, the cell thickness remains constant even when the area is large and at least one of the pair of substrates is flexible, and it remains constant without being affected by temperature changes. It is maintained.

FIG. 1 is a sectional view showing the inside of a first embodiment of the liquid crystal cell of the present invention, cut parallel to the substrate. One substrate 11 is made of, for example, a glass plate, a rigid or flexible plastic plate, etc., and an adhesive part 12 is formed along its periphery for adhering to the other opposing substrate (not shown). has been done. Further, a spacer member 13 is formed in the center of the substrate 11 surrounded by the adhesive portion 12, and serves to regulate the thickness of the liquid crystal layer. The spacer member 13 is formed into a pattern by, for example, coating the substrate 11 with polyimide to a predetermined thickness, and then photo-etching. Or, the substrate 11 itself,
The surface of the substrate may be etched in a pattern except for the spacer portion 13, and the surface of this substrate may be subjected to rubbing treatment to orient the liquid crystal, if necessary. In addition, the liquid crystal layer area 14 is partitioned by the spacer member 13.
is formed, which adjoins or communicates with the vacuum space 16 via the interface 15. Such a liquid crystal layer 14 is formed by injecting liquid crystal through a liquid crystal injection port 17 and sealing the injection port 17 with a sealant 18 . As the liquid crystal material, for example, ferroelectric liquid crystal DOBAMBC is used,
The orientation state is obtained by slow cooling from the isokyoshi phase state to the S m C state. Note that when one liquid crystal cell is used as an electro-optical element, an electrode is formed on the substrate 11, but this is not shown.

To explain in more detail how the liquid crystal is encapsulated, for example, a cell is formed by bonding a substrate 11 on which a spacer member 13 is formed and a flexible counter substrate such as a polyester film using an epoxy adhesive 13 or the like. Thereafter, the cell is held in a vacuum container, and after the air in the cell is sufficiently exhausted, the injection port 17 is immersed in the liquid crystal material. Thereafter, the pressure outside the cell is increased by introducing N2 gas or the like into the vacuum container, and the liquid crystal material is press-fitted into the cell. When the liquid crystal material sufficiently fills the predetermined area (eg, image area) 19, the injection operation is stopped and the injection port 17 is sealed. The liquid crystal cell formed in this manner is subjected to sufficient compressive force at atmospheric pressure due to the presence of the decompressed space 16, so that the counter substrate (not shown) is in close contact with the spacer member 13. , even in extremely thin cells with a thickness of less than 3 l.

It is possible to form cells with uniform cell thickness over a large area. Further, the reduced pressure space 16 is caused by environmental changes when the liquid crystal cell is used. It also has the function of preventing the thickness of the cell from partially changing due to thermal expansion and contraction of the liquid crystal material.

The volume of the decompressed space to achieve the above purpose is usually 1/1000 or more, preferably 1/1000 or more, compared to the potted plant in the liquid crystal layer area.
A value of 7100 or more is preferable, and the upper limit is set to such an extent that the effective display area of the liquid crystal cell does not decrease significantly.

The appropriate pressure in the reduced pressure space is about 1/10 to 1/2 atm.

FIG. 2 shows a further improved i2 of the liquid crystal cell of the present invention.
FIG. 2(a) is a sectional view corresponding to FIG. 1, and FIG. 2(b) is a sectional view taken along line B-B in FIG. 2(a). It is.

In this example, one substrate 21 has a groove-shaped depressurized space 26 formed by etching on its inner surface, and is bonded to the opposing substrate 20. Such a groove-shaped decompression space 2
In Example 6, since a large volume can be obtained with a small substrate area, a sufficient margin is given to the timing when liquid crystal injection is performed and stopped, compared to Example 1, and is suitable for increasing productivity.

FIG. 3 shows a third embodiment.

In this example, a narrow connecting portion 35 is provided between the liquid crystal layer region 34 and the depressurized space 36, and the path length between the connecting portion 35 and the injection port 37 is such that the path length between the liquid crystal layer region 34 and the injection port is set to be the same as the longest path length between. For this reason, during liquid crystal injection, while the required area is being injected,
It is possible to avoid the trouble of the liquid crystal entering the decompressed space.

Further, in the connecting portion 35, a member 40 made of the same material as the spacer member 33 is further provided to narrow the passage to prevent any amount of air remaining in the decompression space 36 from entering the liquid crystal layer area when the cell is in use. , are formed simultaneously with the spacer member 33.

Note that the above-mentioned reduced pressure space 16.26.36 is filled with other suitable gas, such as inert gas (N2, C
O2, Ar, Ne, etc.) is preferably sealed in order to prevent deterioration of the liquid crystal.For this purpose, once the internal space of the cell is evacuated, it is heated to a predetermined atmospheric pressure (preferably 1/1000 to 1/1/1
10 atmospheres), and then press-fit the liquid crystal.

What is necessary is to increase the cell internal pressure to a predetermined pressure of 1 atm or less (1/l 0-172 atm), and after sealing, increase the cell ambient pressure to normal pressure.

As described above, according to the present invention, a spacer member is provided in the gap to be filled with liquid crystal to regulate the cell thickness, and a depressurized space is provided in communication with the liquid crystal layer. A pair of substrates is held in close contact with a spacer member, the cell thickness is constant even when the area is large and at least one of the pair of substrates is flexible, and it is not affected by temperature changes, etc.
A liquid crystal cell having excellent properties such as the following is provided.

[Brief explanation of the drawing]

FIG. 1, FIG. 2(a), and FIG. 3 are sectional views parallel to the substrate of a liquid crystal cell according to an embodiment of the present invention, respectively.
Figure f32 (b) is a sectional view taken along the line cr+BB in Figure 2 (a). 11.21...Spacer forming substrate 20...Counter substrate 12...Adhesive portion 13.33...Φ spacer 14.34...Liquid crystal layer 16.26.36...Decompression space 35... Liquid crystal layer-decompression space connection part 1: Figure 1 1 Cause

Claims (1)

[Scope of Claims] 1. A liquid crystal cell in which a liquid crystal is sealed from at least one liquid crystal injection port into a gap between a pair of substrates, wherein a liquid crystal is filled in a gap between at least one of the substrates in the gap. 1. A liquid crystal cell comprising: a spacer member formed in the spacer; a liquid crystal layer region whose thickness is regulated by the spacer member; and a reduced pressure space communicating with the liquid crystal layer region. 2. The volume of the decompression space is 1/1 of the volume of the liquid crystal layer.
10. The liquid crystal cell according to claim 1, wherein the number of liquid crystal cells is 1000 or more. 3. The path length between the connection part between the liquid crystal layer region and the depressurized space and the injection port is equal to or larger than the longest path length between the liquid crystal layer region and the injection port. A liquid crystal cell according to claim 1, characterized in that: 4. The liquid crystal cell according to claim 1, wherein at least one of the pair of substrates has flexibility. 5. The liquid crystal cell according to claim 1, wherein the depressurized space is provided by a groove formed in at least one of the substrates. 6. The liquid crystal cell according to claim 5, wherein the depressurized space is formed by forming an alignment film on at least one substrate and pattern-etching the alignment film.