JPH08297287A - Liquid crystal optical element and its production - Google Patents

Abstract

PURPOSE: To prevent the nonuniformity within the plane of a liquid crystal/solid composite layer and the intrusion of impurities from a sealed aperture by disposing an island-shaped structural body between the aperture and a display region. CONSTITUTION: The one side of the diagonal parts of a liquid crystal cell having two substrates is provided with a groove without arranging a peripheral seal 1. The one side is provided with such a structural part as to communicate with the outside and the inside of a liquid crystal cell and is used as the aperture 6 of the liquid crystal cell. The position facing the aperture 6 of the inside of the liquid crystal cell is provided with the island-shaped structural body. The structural body is formed simultaneously with the peripheral seal 1 by using an epoxy resin similarly to the peripheral seal 1. The empty cell of the liquid crystal cell having the peripheral seal 1 and the island-shaped structural body 5 is formed and the material of the liquid crystal/solid composite is vacuum injected therein. The liquid crystal cell is thereafter placed in the pressurized state higher than the pressure to embody the desired cell gap and the composite is dropped to the aperture. The parallel irradiation of the panel surface with UV rays is made possible by adopting such island-shaped structural body 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal optical element and its manufacturing method. Specifically, a specific configuration will be disclosed regarding material injection into a liquid crystal cell and means for sealing an injection port in forming a layer of a liquid crystal / solidified composite.

[0002]

2. Description of the Related Art Conventionally, a liquid crystal optical element provided with a liquid crystal / solidified product composite as a light modulation layer does not use a polarizing plate, and is a twisted nematic liquid crystal optical element (TN) in that bright display can be obtained.
There are various methods for forming an element of a liquid crystal / solidified compound composite, which is superior to -LCD) and has been studied as a display for a light control display or an information display. After injecting the uncured liquid mixture with curable material,
There is known a method of forming a liquid crystal phase and a resin matrix phase by polymerizing phase separation by heat or light.

In the case of a liquid crystal optical element formed by adopting this method, in the reliability test of keeping high temperature and high humidity, there is a case where the specific resistance is lowered due to the penetration of water in the vicinity of the injection port.

Further, in the liquid crystal / solidified product composite formed by the photopolymerization phase separation method, the opening is sealed by using the liquid crystal / solidified product composite itself or an ultraviolet curable adhesive or the like. Was there. At this time, there is a problem that the leakage of ultraviolet rays reaches the display area and deteriorates the display characteristics.

[0005]

In the present invention, attention has been paid to the problems that the conventional example has, that is, the mutual relationships in the injection process, the opening sealing process, and the photopolymerization process, and the liquid crystal / solidification process is performed. The present invention is intended to solve in-plane non-uniformity of the object composite layer, contamination of impurities from the sealed opening, and the like. And
A liquid crystal optical element having high efficiency and improved reliability as an electronic element, and a method for manufacturing the same are disclosed.

[0006]

According to the present invention, in a liquid crystal optical element in which a liquid crystal / solidified product composite is provided as a light modulation layer and a sealed opening is provided, the opening and the display area are formed. Provided is a liquid crystal optical element having an island-shaped structure provided therebetween. This is called the first invention.

Further, in the first invention, there is provided a liquid crystal optical element characterized in that the opening is sealed with a photocurable material. This is called the second invention.

Also, in the first or second invention, there is provided a liquid crystal optical element characterized in that the shape of the island-shaped structure is concave toward the display region side. This is called the third invention.

In addition, an island-shaped structure is provided between the opening and the display area to form an empty cell, and a liquid mixture of liquid crystal and a photo-curable material is injected into the empty cell through the opening, and the vicinity of the opening is filled. Of the liquid crystal optical element, wherein the liquid mixture is irradiated with light to cure the photocurable material, the opening is sealed, and the liquid mixture is irradiated with light. A manufacturing method is provided. This is called the fourth invention.

An island-shaped structure is provided between the opening and the display region to form an empty cell, and a liquid mixture of liquid crystal and a photo-curable material is injected into the empty cell through the opening and then the opening is formed. A liquid crystal / solidified product composite is formed by encapsulating a photo-curable adhesive in the resin, curing the adhesive with light, sealing the opening, and irradiating the liquid mixture with light. A method for manufacturing a liquid crystal optical element is provided. This is called the fifth invention.

In the present invention, a resin is specifically used as the solidified product of the liquid crystal / solidified product composite. Improvements in the device formation and reliability can be achieved. First, an island-shaped structure is provided inside the liquid crystal cell to separate the opening from the display area on the cell inner side. By providing such a structure, it is possible to eliminate a defect that occurs when forming the sealing of the opening. Further, in the long term, it is possible to prevent contamination from entering from the outside of the liquid crystal cell.

As the shape of the island-shaped structure, a linear shape, a concave shape, a convex shape, a wedge shape, an elliptical shape, a teardrop shape, a streamline shape, or the like can be used, as in Examples described later. Above all,
The shape and arrangement is preferably such that the flow of the liquid mixture during injection into the empty cell is not hindered. For example, a concave shape is preferable. At the same time, a length is required to prevent the adhesive for sealing the opening from spreading to the display area.
In practice, when forming the perimeter seal, the same material is used to simultaneously form the island structure. Examples will be described below.

[0013]

【Example】

(Embodiment 1) FIG. 1 shows a partial plan view of a liquid crystal cell in this embodiment. One of the diagonal parts of a liquid crystal cell having two substrates
Grooves with no perimeter seals on the sides. Then, a structure is provided in which the outside communicates with the inside of the liquid crystal cell and is used as an opening of the liquid crystal cell. Then, the island-shaped structure was provided at a position facing the opening inside the liquid crystal cell. Similar to the peripheral seal, an epoxy resin was used and the peripheral seal was formed at the same time. The width of the opening of the peripheral seal was 3 mm, the length of the island-shaped structure was 4 mm, the width was 0.2 mm, and the distance from the opening was 3 mm.

An empty cell of a liquid crystal cell having such a peripheral seal and an island structure was formed, and the liquid crystal / solidified material composite material was vacuum-injected into the empty cell. It is a liquid mixture in which a liquid crystal, a photocurable acrylic monomer, a photocurable acrylic oligomer, a photopolymerization initiator and the like are mixed.

Then, the liquid crystal cell was placed under a pressure slightly higher than the pressure for realizing the desired cell gap, and an ultraviolet curable adhesive (3052 manufactured by ThreeBond Co., Ltd.) was dropped into the opening.

The adhesive was drawn into the liquid crystal cell by reducing the pressure to a predetermined pressure, and ultraviolet rays of 1000 mJ / cm ² were spot-irradiated near the opening to cure the adhesive.

Next, by exposing the entire liquid crystal cell to ultraviolet rays, a liquid crystal / solidified product composite which functions as an electro-optical functional layer was formed by a photopolymerization phase separation method. In the liquid crystal optical element formed by this manufacturing method, no characteristic unevenness due to ultraviolet leakage was observed when the adhesive was cured in the vicinity of the opening.
Furthermore, the diffusion of the adhesive can be suppressed, and no characteristic unevenness due to this can be seen.

By adopting the island-shaped structure of the present invention, it becomes possible to irradiate ultraviolet rays in parallel with the panel surface. That is, the island-shaped structure did not block the ultraviolet spot light and did not affect the display area. In this way, it becomes possible to stack and press the liquid crystal cells in the pressing process for controlling the gap of the liquid crystal cells. Then, it was possible to reduce the variation of the cell gap, improve the yield, and improve the productivity.

This liquid crystal cell was subjected to a high temperature and high humidity reliability test (60
(° C / 90% RH-500H), the decrease in the specific resistance in the vicinity of the opening could be suppressed to about 20% of the initial value.

(Embodiment 2) FIG. 3 shows a partial plan view of this embodiment. A curved island-shaped structure was provided, which was concave toward the inside of the liquid crystal cell and convex toward the opening. The shape of the peripheral seal is the first embodiment.
Same as. Then, an electro-optical function layer of a liquid crystal / solidified product composite was formed by the same process as in Example 1. As a result, no characteristic unevenness was observed as in Example 1, and the high temperature and high humidity reliability was also improved.

(Embodiment 3) FIG. 4 shows a partial plan view of this embodiment. A curved island-shaped structure having a convex shape inward of the liquid crystal cell and a concave shape on the opening side was provided. The form was the reverse of that of Example 3.
The shape of the peripheral seal was the same as in Example 1. Then, an electro-optical function layer of a liquid crystal / solidified product composite was formed by the same process as in Example 1. As a result, no characteristic unevenness was observed as in Example 1, and the high temperature and high humidity reliability was also improved.

Comparative Example An electro-optical functional layer of a liquid crystal / solidified product composite was formed in the sealed cell shown in FIG. 2 by the same process as in the example. The width of the opening of the peripheral seal was 3 mm. In this liquid crystal optical element,
When the opening was sealed, the ultraviolet spot light was diffused to the region where the desired characteristics were required, and thus unevenness in the display characteristics was observed. Furthermore, characteristic unevenness due to diffusion of the adhesive was also observed. As shown in FIG. 2, the defective portion X in which the characteristic unevenness occurred was found near the opening.

Further, in the pattern of the peripheral seal in the present invention, when the ultraviolet light is irradiated in parallel to the panel surface, there is a large area where characteristic unevenness occurs, and the cells can be stacked and pressed as in the above-mentioned embodiments. However, the yield and the productivity were largely inferior.

Further, when this liquid crystal cell was put into a high temperature and high humidity reliability test (60 ° C./90% RH-500H), the decrease in the specific resistance in the vicinity of the opening was about 70 with respect to the initial value.
%Met.

[0025]

According to the present invention, the structure of the display area can be made uniform. In addition, a plurality of liquid crystal cells can be simultaneously pressed in the manufacturing process.

Also in terms of long-term reliability, it has become possible to prevent the intrusion of impurities from the outside.

Further, the present invention can be applied in various ways within the range of not impairing its effect.

[Brief description of drawings]

FIG. 1 is a partial plan view of a liquid crystal cell according to a first embodiment of the present invention.

FIG. 2 is a partial plan view of a liquid crystal cell of a comparative example.

FIG. 3 is a partial plan view of a liquid crystal cell according to a second embodiment of the present invention.

FIG. 4 is a partial plan view of a liquid crystal cell according to a third embodiment of the present invention.

[Explanation of symbols]

 1: Peripheral seal 2: Glass substrate (upper surface) 3: Glass substrate (lower surface) 4: Display area 5: Island structure 6: Opening S: Ultraviolet light spot

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoyuki Ishihara 1150, Hazawa-machi, Kanagawa-ku, Yokohama, Kanagawa Asahi Glass Co., Ltd. Central Research Laboratory (72) Inventor Tsuneo Wakabayashi 1160, Matsubara, Hazawa-machi, Kanagawa-ku, Yokohama A・ In G Technology Co., Ltd.

Claims (5)

[Claims] 1. A liquid crystal optical element provided with a liquid crystal / solidified body composite as a light modulation layer and having a sealed opening, wherein an island-shaped structure is provided between the opening and the display region. Liquid crystal optical element characterized by the above. 2. The liquid crystal optical element according to claim 1, wherein the opening is sealed with a photocurable material. 3. The liquid crystal optical element according to claim 1, wherein the island-shaped structure has a concave shape toward the display region side. 4. An empty cell is formed by providing an island-shaped structure between the opening and the display region, and a liquid mixture of liquid crystal and a photocurable material is injected into the empty cell through the opening, and the vicinity of the opening is filled. Of the liquid crystal optical element, wherein the liquid mixture is irradiated with light to cure the photocurable material, the opening is sealed, and the liquid mixture is irradiated with light. Production method. 5. An island-shaped structure is provided between the opening and the display area to form an empty cell, a liquid mixture of liquid crystal and a photo-curable material is injected into the empty cell, and then the opening is formed. A liquid crystal / solidified product composite is formed by encapsulating a photo-curable adhesive in the resin, curing the adhesive with light, sealing the opening, and irradiating the liquid mixture with light. A method for manufacturing a liquid crystal optical element.