JPS59127021A - Production of electro-optic element - Google Patents

Abstract

PURPOSE:To inject a liquid material into a long-sized empty cell without allowing entry of foam with respect to a method for injecting a liquid crystal, etc. into the long-sized empty cell by holding the empty cell in a vacuum, and covering the feed ports provided at >=2 points with the liquid material which can cause an electro-optic change then restoring the atmospheric pressure therein. CONSTITUTION:An empty cell 1 is provided with feed ports 2, 2' and is provided with a gap formed by placing a pair of base plates oppositely to each other via a sealing spacer 8. A boat 4 filled therein with a liquid material 5 which can cause an electro-optic change is disposed in a vacuum device 9 and said material is sucked up by a capillary tube 3. A liquid material 5' of the same material as the material 5 filled in the boat 4 is further filled in a boat 4 and a capillary tube 3' is immersed therein. The inside of the device 9 is evacuated to a vacuum and the tubes 3 and 3' are brought into contact with the ports 2 and 2' of the cell 1 to cover the ports with liquid materials 10 and 10' and thereafter the tubes are detached. When the inside of the device 9, is estored to the atmospheric pressure the materials 10 and 10'are injected into the cell 1 by the difference in the atmospheric pressure between the inside and the outside of the cell 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electro-optical @barrier, particularly to a method for manufacturing a liquid crystal shutter array, and more particularly to a method for injecting liquid crystal into a long empty cell.

As a method for injecting liquid crystal into an empty cell, for example, a capillary two-drop method or a vacuum injection method is known. The capillary tube method and the drop method have drawbacks such as poor productivity and the mixing of air bubbles into the liquid crystal, and are therefore not used at present. According to a patent, if air bubbles are mixed into the liquid crystal, the life of the liquid crystal will be reduced by up to 1/100.In the liquid crystal injection method, it is absolutely necessary to avoid air bubbles from entering the liquid crystal.

Currently, as a method for injecting liquid crystal into empty cells, a method using a pressure difference between a vacuum and the atmosphere is generally used in terms of productivity and prevention of air bubbles. The vacuum injection method is, for example, the immersion method disclosed in JP-A No. 49-79543, or the immersion method disclosed in JP-A-49-79543.
7-22593 and 52-27653, etc., are known methods for supplying liquid crystal directly to an injection port, but this method is not suitable for applications such as long empty cells such as liquid crystal-shutter arrays or large liquid crystal panels. At present, an effective method for injecting liquid crystal into empty cells has not yet been found. In particular, conventional methods have low productivity and may cause air bubbles to be mixed into long empty cells, and are often used in the manufacture of liquid crystal optical elements such as liquid crystal shutter arrays, which require high reliability. There was an intercondylar point.

An object of the present invention is to provide a method for manufacturing a liquid crystal optical element using an injection method that solves the above-mentioned drawbacks.

Another object of the present invention is to provide a method for manufacturing a liquid crystal optical element using an injection method that can reliably fill a long or large empty cell with liquid crystal.

Another object of the present invention is to provide a liquid crystal injection method that is easy to work with, is suitable for mass production, and can supply highly reliable liquid crystal optical elements.

Such an object of the present invention is to place a long (length: 15cIT1 or more) or large-sized empty cell having injection ports at two or more places under vacuum, and then insert the injection ports at two or more places. is covered with a liquid substance capable of producing an electro-optical change, such as a liquid crystal or an electrochromic substance, and then the injection port is covered within the empty cell by applying a pressure difference between the inside and outside of the empty cell. This is achieved by a method of manufacturing an electro-optical device that includes a step of injecting a liquid substance.

In the present invention, it is preferable to provide the injection port on the short side of the long empty cell, and it is particularly desirable to provide one injection port on each side of the short side. A method for placing a liquid substance in an injection port is, for example, by filling a capillary with a liquid substance in advance and bringing its tip into contact with the injection port.
A liquid crystal material can be placed in the inlet.

Furthermore, in the method of the present invention, it is preferable that the vacuum device is already in a vacuum state at the stage of filling the capillary with liquid crystal, which allows the capillary to always be filled with liquid crystal that does not contain water. Therefore, it is possible to effectively prevent the liquid crystal from falling off from the capillary tube, which occurs along with the bumping phenomenon.

If the other end of the capillary tube is immersed in a boat filled with a liquid substance, the liquid substance can be sent to the other end of the capillary tube by the capillary field.

The capillary tube used in the present invention has an inner diameter of 0.
25t≦d≦2.5t (where t indicates the thickness of the cell.

), but d may exceed 2.5t. Also, 0.25 tK is satisfied (Tomoyo(,/l?
It is not limited to. The general inner diameter d of the capillary tube is preferably about 0.1 mm to 7 mm. Further, the capillary tube can be made from a wide variety of materials, but preferably glass, stainless steel, aluminum, or an alloy thereof is suitable.

The present invention will be explained below with reference to the drawings.

Figure 1 is a cross-sectional view of a vacuum injection apparatus suitable for use in the method of the present invention.

In Figure 1, empty cells 2 and 2' indicate injection ports for injecting a liquid substance to produce an electro-optical element such as a liquid crystal. The empty cell 1 has a gap formed by placing a pair of substrates (e.g., glass, polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polyvinyl acetate, polystyrene, polymethacrylate, etc.) facing each other with a seal spacer 8 in between. It is set up. This gap is generally thin, typically 5 to 50 microns. The inlets 2 and 2' are generally on the order of 2 mm wide, and may be wider (or less). It can be formed as a hole, or it can also be provided at a location other than the effective display surface of the substrate.

The empty cell 1 is first placed in the vacuum device 9 by opening the lid (not shown) of the vacuum device 9.

At this time, a liquid substance 5 (e.g., liquid crystal, electrochromic material, etc.) that causes an electro-optical change in the vacuum device 9
A boat 4 and a capillary tube 6 filled with (
. One opening of the capillary tube 6 is arranged to be immersed in the liquid substance 5, and at this time, the liquid substance 5 reaches the other opening of the capillary tube 6.
is sucked up by capillary action.

Furthermore, the boat 4' is filled with a liquid substance 5' of the same type as the liquid substance 5 filled in the boat 4, and a capillary tube 6' is inserted into this liquid substance 5'. The capillary tube 3' is filled with liquid substance 5' by soaking. Then,
After sealing the vacuum device 9, the leak valve valve is closed and the exhaust valve 7 is opened to make the inside of the vacuum device 9 evacuated. The vacuum state varies depending on the capacity of the empty cell, but is generally 10 Torr or less,
Preferably, the Q is set to 5 Torr or less.

In particular, if a liquid crystal is exposed to the atmosphere during the humid summer months, moisture in the atmosphere will be contained in the liquid crystal, so if the liquid crystal is placed in a vacuum, the moisture will bump. In addition, liquid crystal optical elements made by injecting liquid crystal containing water into the empty cell 1 have an extremely short lifespan compared to those that do not contain water, so it is important to avoid the contamination of water into the product optical element. must be completely prevented.

Next, the capillaries v6 and 6' are brought into contact with the injection ports 2 and 2' of the empty cell 1, respectively, to
' are covered with liquid substances 10 and 10', after which capillary tubes 6 and 6' are respectively inserted and removed from the inlets 2 and 2'. When the inside of the vacuum device 9 is returned to atmospheric pressure by closing the exhaust valve 7 and opening the leak valve 3, the pressure difference between the air pressure in the empty cell 1 and the atmospheric pressure causes a The liquid substance 10 and 10' that covered the inlets 2 and 2' is injected into the empty cell 1. Furthermore, the inside of the vacuum device 9 can be brought to atmospheric pressure or higher if necessary.

Further, the boats 4 and 4' used in the method of the present invention can be made of glass, plastic (polyfluoroethylene, polyvinyl chloride, polymethacrylate), stainless steel, aluminum, etc. The outer diameter of the capillary tubes 6 and 6' may be slightly thicker, and the depth of the liquid substances 5 and 5' may be 1 to 2 mm seconds. Therefore, the liquid substances 5 and 5' may be exchanged. Even in some cases, it is possible to reduce the amount of waste.

Hereinafter, the present invention will be explained based on examples.

Example 1 A 211 stainless steel liquid crystal boat was placed in the vacuum apparatus shown in Figure 1, and a $1 glass capillary tube with an inner diameter of 2 mm and a length of 5 mm had one end immersed in the liquid crystal in one boat. , a second glass capillary tube with an inner diameter of 2 mm and a length of 5 mm with one end immersed in the liquid crystal in the other boat, and a long tube (length: 25 cm) with two injection ports of 2 mm in diameter.
) empty cells were placed from the insertion slot. Two liquid crystal boats were injected with 20 centipoise nematic liquid crystal to a depth of 2 mm. After placing these members in a vacuum device and sealing the vacuum device, the leak valve was closed and the exhaust valve was opened to bring the inside of the vacuum device into a vacuum state of Q, 1 Torr. At this time, a bumping phenomenon caused by moisture occurred in the liquid crystal in the liquid crystal boat, and the moisture was removed from the liquid crystal.

The empty cell is then lowered and then immersed into the other boat until the inlet provided on the lower side of the empty cell is filled with the liquid crystal supplied by the capillary to one port of the capillary chamber. Pull down the other capillary tube that was
The lower end of the capillary tube was moved to the injection port provided above the empty cell, and the injection port provided in the empty cell was covered with liquid crystal.

Thereafter, the exhaust valve was closed and the leak valve was opened to introduce atmospheric air into the vacuum apparatus. At this time, Qn, which had one injection port, penetrated into the empty cell, and within 7.5 minutes, the long empty cell was completely retracted with liquid crystal.

FIG. 2 is a cross-sectional view of another Q-shaped vacuum injection device for use in the method of the present invention.

In Fig. 2, the same reference numerals and the same members as in Fig. 1 are shown. It has a structure in which the capillary tube 6 is integrated with the boat 4 under vacuum, and one mouth of the hair MU〒f3 is placed in the liquid IS substance 5 that causes electro-optical changes, and the hair M
A liquid substance 5 that causes an optical change is supplied to the other opening of the tube 13. Also, one capillary tube 6' is immersed in the liquid substance 5 in the boat 4, and then this capillary tube 6' is pulled up to fill the injection port 2 provided above the empty cell 1.
The 'F end of the capillary tube 3' is brought into contact with ', and the two injection ports 2 and 2' are covered with liquid crystal materials 10 and 10'. Thereafter, the inside of the vacuum device 9 is returned to atmospheric pressure by the same method as described above (thus, the liquid substances 10 and 10' can be injected into the perforated cell 1).

[Brief explanation of drawings]

Figures 1 and 2 are schematic diagrams showing the manner in which the method of the present invention is carried out. 1... Empty cell 2, 2'... Inlet 6.3'.
...Capillary tube 4,4'-...Boat 5.5'...9 Liquid substance 6...Leak valve 7...* Exhaust/(lube,
8・■ Seal spacer 9 ... Vacuum device 1
0.10'...Liquid substance covering the injection port Patent Applicant Canon Co., Ltd.

Claims (1)

[Claims] A method for manufacturing an electro-optical element, comprising the step of injecting a liquid substance into an empty cell having injection tops at two or more locations under vacuum.