JPH0511257A - Production of liquid crystal display element - Google Patents

Abstract

PURPOSE:To allow the use of thermoplastic high-polymer film substrates in a curved state and to obviate the intrusion of adhesives, etc., therein so as to improve reliability by using the above-mentioned substrates and sealing the substrates to each other by thermal welding simultaneously with cutting by using cutters with heaters. CONSTITUTION:Transparent electrodes 2 extending in a Y direction and an oriented layer are formed on the surface of the film-like upper substrate 1 consisting of polyethylene terephthalate. The lower substrate 3 is formed of the polyethylene terephthalate film and the transparent electrodes 4 extended in an X direction and the oriented layer are formed on this substrate. Spacers having 10mum grain size are distributed and disposed therebetween. Two sheets of such substrates are so superposed on each other that the positioning marks of the respective substrates mate each other, by which the dot matrix type liquid crystal display element substrates 9 are formed. The superposed substrates 9 are inserted between the cutters 10 and 11. The cutters 10, 11 have the electric heaters 12, 13 setting, the surface temps. of the blades of which are set at the temp. suitable for welding. The substrates 9 are cut by butting the cutters 10, 11 against each other and simultaneously, the substrates 9 are welded except a liquid crystal injection port 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly to a method for manufacturing a liquid crystal display device using a thermoplastic polymer substrate as a sandwich of a liquid crystal composition.

[0002]

2. Description of the Related Art Conventionally, a glass substrate has been used as a substrate constituting a liquid crystal display element. However, with the spread of the liquid crystal display element, a lighter and thinner liquid crystal display element of high display quality is required. It's coming. For lightweight and thin type, it is effective to use a thermoplastic polymer substrate as the substrate.

Generally, when manufacturing a liquid crystal display element, a pair of substrates having a transparent electrode having a predetermined pattern on the facing surface and an alignment layer formed on the transparent electrode are used. For the workability and the protection of the transparent electrodes, a pair of substrates having a larger transparent electrode area than a predetermined pattern is used. In order to keep the gap between the substrates uniform, a gap material called a spacer is arranged between the two substrates, and an adhesive (sealant) is applied to the peripheral edge of the substrates, and then the two substrates are superposed. The adhesive is cured in a state of being pressurized and heated to produce an envelope, which is cut into a desired size, and then the liquid crystal composition is injected into the envelope and the injection port is sealed. It is formed.

Such a manufacturing method is also applied to a liquid crystal display device using a thermoplastic polymer substrate.

[0005]

However, when two substrates of thermoplastic polymers are superposed and the adhesive is cured under pressure and heat, the deformation or "waviness" of the thermoplastic polymer substrates occurs. This causes a problem that the position of superposition shifts during curing of the adhesive.

A liquid crystal display device using a thermoplastic polymer substrate is practically used in a curved shape. There is a thing. However, the liquid crystal display device using the thermoplastic polymer substrate manufactured by the above-mentioned manufacturing method does not have sufficient strength for use in a curved form, and in particular, the adhesive and the thermoplastic polymer substrate at the peripheral edge of the substrate are used. There is a problem in that the liquid crystal composition between the substrates flows out to the outside because the adhesive strength with the is weak.

[0007]

In the present invention, at least one of the two substrates on which an electrode and an alignment layer are formed is a thermoplastic polymer substrate, and the two substrates are opposed to each other by the alignment layer. And a step of arranging a gap material on the surface of at least one orientation layer of the two substrates in a distributed manner and superposing the two substrates so that the orientation layers face each other, and the thermoplastic polymer A method for manufacturing a liquid crystal display element is characterized in that the substrate is cut and, at the same time, the other substrate is partially welded.

[0008]

The present invention will be described together with a method of manufacturing a dot matrix type liquid crystal display device using two thermoplastic polymer substrates on which electrodes and an alignment layer are formed and its function. On one of the lower substrate on which electrodes are formed in the X direction and on the upper substrate on which electrodes are formed in the Y direction, a gap material is arranged to keep the substrate gap uniform. The electrodes on the substrate are stacked so that the electrodes are at the desired positions. After that, it is cut into a desired size by punching with a Thomson cutter or the like. When punching, heat is applied to the blade of the cutter, so that the two thermoplastic polymer substrates are welded by the heat of the blade of the cutter. At this time, the side of the substrate on which the electrode portion for inputting an electric signal for driving the liquid crystal display element is formed is left, but the electrode portion can be left by providing a step on the blade.

The liquid crystal display element produced by this cutting and welding method is not only sufficiently usable in a curved state because the two substrates are held by the welding effect, but also can be applied to a liquid crystal composition by an adhesive. Since no impurities are mixed in, the reliability of the liquid crystal display device is also improved. Further, it becomes possible to reduce the number of steps for manufacturing the liquid crystal display element.

[0010]

【Example】

 (Example 1) The present invention will be described below with reference to examples.

As shown in FIG. 1 (a), the upper substrate 1 is a kind of thermoplastic polymer and has an outer shape of 230 mm × 185 mm and a thickness of 0 mm.
-It is made of a 1 mm polyethylene terephthalate film, and a transparent electrode (total electrode shape area 215 x 173 mm) 2 and an alignment layer extending in the Y direction are formed on the surface.

The lower substrate 3 is formed of a polyethylene terephthalate film having an outer shape of 230 mm × 185 mm and a thickness of 0.1 mm, and has a transparent electrode (total electrode shape area 219 × 165 mm) 4 and an alignment layer extended in the X direction. Then, a pore forming agent having a particle size of 10 μm is distributed and arranged. Two of these substrates,
The substrates 1 and 3 are opposed to each other so that the alignment marks 5 and 7 and 6 and 8 of each substrate are aligned with each other to form a dot matrix type liquid crystal display element substrate 9.

The superposed substrate 9 is inserted between the cutters 10 and 11 shown in FIG. 1 (b). The cutters 10 and 11 are equipped with electrothermal heaters 12 and 13 that set the surface temperature of the blades to 260 ° C., which is suitable for welding. The cutters 10 and 11 are butted against each other to cut the substrate 9, as shown in FIG. 1 (c). A cell 14 of a liquid crystal display device was obtained. At this time, in order to form the liquid crystal injection port 19 into which the liquid crystal composition can be injected, the heaters 15 and 16 are provided in the cutters 10 and 11, respectively, and at the same time, a step 17 is formed on the cutter to leave a side for electrode extraction. 1
8 is provided.

The structure and operation of the cutter will be described in more detail with reference to FIG.

As shown in FIG. 2 (a), the upper cutter 10 cuts the upper substrate 1 along a predetermined size and heat-welds the periphery 1c, 1d except the electrode lead-out sides 1a, 1b of the upper substrate 1.
Disconnect. In order to leave the upper and lower electrode lead-out sides 1a and 1b without cutting, the blade 1 of the cutter 10 corresponding to these sides
0a, 10b with the tip edges 17a, 17b of the other blade 10
From the leading edges of c, 10d, 10e, and 10f to the substrate 1
A step 17 is formed between the blade and another blade by the amount corresponding to the film thickness. When the upper and lower cutters are butted to each other in the cutting and welding step, the superposed substrate 9 sandwiched between these cutters is cut and welded, but at this time, the sides 1a and 1b are left without being cut. Behind each side is an electric heater 1
2 (FIG. 1 (b)) is arranged so that when the substrate of the organic resin film and the blade come into contact with each other, the substrate is in a melted and softened state. There is a heater 15 behind the blade 10d on one side, so that even if the substrate 9 is cut, the cut portion is not heat-welded and the liquid crystal injection port 19 is secured.

The lower cutter 11 cuts the lower substrate 3 and, at the same time, cooperates with the upper cutter 10 to weld the substrates 1 and 3. As shown in FIG. 2 (b), the lower substrate 3 has transparent electrodes extending in the X direction, and when the substrate side 3c at the electrode extension end is cut off from the other sides 3a, 3b and 3d, the electrode It must be left as a derived edge. Therefore, the tip edge 18c of the blade portion 11c corresponding to the side 3c is connected to the other blade portions 11a, 11b, 1
The step 18 is made to be retracted by the thickness of the substrate from the leading edges of 1d, 11e and 11f.

An electric heater 13 (FIG. 1B) is arranged behind the cutter blade so that the surface temperature of the blade is heated to 260 ° C. except for the blade portion 16 located at the liquid crystal inlet. .. The substrate punched out by the butting of the cutters 10 and 11 is, as shown in FIG. 1 (c), its four sides are sealed by welding except the liquid crystal injection port, and the electrodes of the upper and lower substrates 1 and 3 are led out. The sides 1a, 1b and 3c are left behind. The other substrate side corresponding to these derived sides, for example, 11a for 1a
Is cut by a cutter and is welded to the electrode forming surface of the lead-out side 1a at the cut position.

A liquid crystal display device was prepared by filling the cell 14 prepared as described above with the liquid crystal composition from the liquid crystal injection port 19. When this liquid crystal display device was tested according to JIS K7118, no external problems such as peeling of two substrates occurred.

Further, the present liquid crystal display device is operated at 80 ° C. and 95% RH.
After leaving it to stand for 100 hours, the liquid crystal display device was turned on and no adverse effect was observed on the display.

Example 2 Instead of the film substrate of polyethylene terephthalate which is a thermoplastic polymer material of the substrate 1 in Example 1, a 1.1 mm thick glass substrate having TFT elements formed on the substrate was used.

This substrate 1 and a PES polyethersulfone film having a thickness of 0.1 mm are formed on the surface of R.
G. The film substrate 2 in which a color filter of B3 color was formed and ITO was further formed on the entire surface thereof was used. These are superposed through a gap material, and at the time of cutting, the film substrate 2
Only this was cut and welded to the substrate 1 to prepare a cell of a liquid crystal display element. A fatigue test and a reliability test were performed under the same conditions as in Example 1, but no abnormality was found in appearance and display.

[0022]

As described above, according to the method of manufacturing a liquid crystal display element of the present invention, since two substrates are held by the welding effect, not only can it be used in a curved condition, Since no impurities are mixed in with the adhesive, a liquid crystal display element with improved reliability can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a method for manufacturing a liquid crystal display element of the present invention, in which (a) is a substrate configuration, (b) is a cutter configuration,
(c) shows a cell of the liquid crystal display element cut and welded.

2 is a view for explaining the operation of the cutter of FIG. 1, (a)
3B is a schematic diagram showing the relationship between the upper substrate and the upper cutter, and FIG. 6B is a schematic diagram showing the relationship between the lower substrate and the lower cutter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Upper substrate 3 ... Lower substrate 1a, 1b, 3c ... Electrode leading side 10 ... Upper cutter 11 ... Lower cutter 12, 13 ... Electrothermal heater 14 ... Liquid crystal display element cell 17, 18 ... Cutter step 19 ... Liquid crystal injection port

Claims (1)

Claim: What is claimed is: 1. A thermoplastic polymer substrate is used as at least one of two substrates on which an electrode and an alignment layer are formed, and the two substrates are arranged so that the alignment layers face each other. And a step of arranging a gap material on the surface of at least one alignment layer of the two substrates and superposing the two substrates so that the alignment layers face each other, and the thermoplastic polymer substrate A method for manufacturing a liquid crystal display element, which comprises simultaneously cutting the substrate and welding the other substrate except a part thereof.