JPS6011330B2 - Manufacturing method of liquid crystal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for manufacturing a liquid crystal display device.

The chemical properties of liquid crystal materials change when a crab field is applied,
Utilizing this property, it is used for pattern display, mode pattern observation, irradiation energy detection in holography, shading of optical communication cameras, light valves, decorative materials, etc.

A liquid crystal display device has a structure in which a liquid crystal material is filled between two substrates held at a predetermined distance by a spacer, and conventionally, a glass plate has been used as the substrate.

Further, the substrate is provided with a conductive film for applying a tortoise field, a back light absorbing or reflecting film, etc., as necessary. A conventional liquid crystal display device had a structure shown in FIGS. 1 to 3 before liquid crystal was sealed. That is, the spacer 3 is sandwiched between the substrates 1 and 2, and the substrate 1
, 2 at constant intervals, and a liquid crystal inlet 4, a liquid crystal outlet 5, etc. are provided on the spacer 3 or the substrate 1. In the liquid crystal display device having the structure shown in FIGS. 1 and 2, the bag counterfeit is placed in a vacuum system, and when the system reaches about 0.1 to 10 Hg, liquid crystal material is poured from the liquid crystal injection port 4. After that, the system was returned to normal pressure and the liquid crystal material was introduced and filled into the device. Further, in the liquid crystal display device having the structure shown in FIG. 3, the liquid crystal inlet 4 is immersed in the liquid crystal material, and the air inside the device is sucked through the liquid crystal outlet 5 to introduce and fill the device with the liquid crystal material. After the liquid crystal was introduced and filled as described above, the liquid crystal inlet 4 and the outlet 5 were sealed with a sealant 7 as shown in FIG. 4, for example.

However, such conventional methods have the following drawbacks and cannot be said to be industrially excellent methods.

■ When injecting liquid crystal material, the injection port 4 is immersed into the liquid crystal, so the liquid crystal adheres to the vicinity of the injection port, and the adhered portion is not recovered, resulting in poor liquid crystal yield. When the liquid crystal inlet 4 is immersed in the liquid crystal substance 6, the liquid crystal substance is easily contaminated and deteriorated.

In order to overcome these drawbacks, the inventor of the present invention conducted extensive research and found that if a flexible plastic substrate was used instead of a glass plate as the substrate and manufactured using a special method, the manufacturing process could be greatly simplified. The present invention was completed by discovering that a liquid crystal display device with perfect airtightness can be obtained.

In other words, the gist of the present invention is to process two substrates each having a transparent conductive film formed on a flexible transparent plastic substrate, one of which is processed into a display electrode and the other into a counter electrode, and where the two are placed facing each other, with a part that will serve as an injection port. In a manufacturing method for a liquid crystal display device in which the liquid crystal material is injected from the injection port after the surrounding area is covered with a sealant, the injection port portion is made to protrude, the liquid crystal material is bonded after injection, and then A method for manufacturing a liquid crystal display device characterized by cutting a protruding portion.

The present invention will be described in detail below. In the present invention, a plastic film is used as a substrate.

When using a plastic film as a substrate, the plastic film has physical and chemical properties such as heat resistance, chemical resistance, conductive film adhesion, resistance value, visible light transmittance, flatness, film strength, and optical rotation. It is required that various physical properties are hidden. Recently, transparent plastic sheets that have almost all of these properties have appeared, and there is still an opportunity for improvement. Typical examples include polyester films such as polyethylene terephthalate (PET) film, polybutyresoterephthalate (PBT) film, polyether sulfonate film, and polycarbonate film with a transparent conductive layer of indium oxide. Can be mentioned. In order to use these films for panel substrates, it is usual to use a film whose surface has been subjected to orientation treatment such as oblique vapor deposition of Si0 in order to enhance the liquid crystal effect. As shown in FIG. 5, first, a sealant 7 is applied along the inner periphery of at least one of two flexible plastic substrates 1 having thin film electrodes on its surface by screen printing, transfer method, or the like.

The sealing agent 7 used is one made of an ultraviolet curable resin or a thermosetting resin, the main component of which is a resist that satisfies the following conditions. , 11 [A] Must be able to be bonded to flexible plastic substrates. '
o' It should be possible to print on the substrate.

1) It must be possible to evaporate the solvent and dry it before curing.

8. When irradiated with light or heated, it undergoes a crosslinking reaction and hardens. Various specific examples of these sealants include a known photoresist that is cured by ultraviolet rays, and a resin composition containing the following component.

'a} Initiator that generates radicals by ultraviolet rays, [b
} Nylon and epoxy resin, [c' above {a-(
A solvent that can dissolve the plastic substrate as well as the plastic substrate.

The initiator that generates radicals when exposed to ultraviolet rays used as the component 'a' is a compound that generates radicals when exposed to ultraviolet rays and initiates a curing reaction, such as a dialkyl carbamate group such as a diethyldithiocarbamate group. Mention may be made of terminal-terminated organic compounds, such as diazo compounds, or mixtures of thiols and anthraquinones.

As for the nylon used as one of the components, all polyamide resins such as 6-nylon, 6.6-nylon, and 12-nylon can be used, but those with a melting point Tm of 6000
<Tm>150°C is preferred. As the {b} component epoxide resin to be mixed with nylon, any of the glycidyl ether type, glycidyl ester type, glycidyl amine type, cycloaliphatic type, and linear aliphatic type can be used, and the molecular weight is It is preferably a liquid with a relatively low molecular weight of 300 to 40 stars, and is crosslinked with nylon. Epoxy resins with large molecular weights are not desirable because they do not mix well with nylon and the cured product becomes brittle. The ratio of nylon to epoxy resin in component [b} is suitably 2:1 to 5:1. Note that it is preferable to add phthalyl peroxide or the like to the [b' component, since it will be more strongly cured by ultraviolet irradiation. While dissolving the above {a-component, 'b} component,
The solvent e} that can dissolve a plastic substrate made of polyester or polyenal sulfonate is 1.1
・1,3,3,3-hexafluoro-2-propanol (HFIP), methyl acetate, ethyl acetate, trichloroethylene, methylene chloride, methyl ethyl ketone, cellosolve acetate, dioxane, tetrahydrofuran, chloroform, 2-nitropropylene In addition to single solvents such as /gun, nitromethane, phenol, and metacresol, toluenetanol, toluennoacetone, solvent naphtha/acetone, carbon tetrachloride/acetone, n-butylnotolene acetate, DOP/acetone, etc. Examples include mixed solvent systems. Further, as a specific example of a thermosetting resin, for example, polybutadiene described in the Japanese Patent Publication Publication No. 48-12 Ban 7 Ku 48-2 Kadabimochi is prepared by a cyclization reaction to form 6 true rings in the molecule singly or consecutively. Mention may be made of the produced cyclized polybutadiene resins.

When this cyclized butadiene rubber is used, 150~
When heated to 200° C. for 20 to 4 minutes, a crosslinking reaction occurs and adhesion occurs. Of course, in the present invention, any sealant that satisfies the above conditions can be used as well. Next, the other substrate 2 is placed one on top of the other, and after the sealant is cured, the liquid crystal injection part is trimmed into a protruding shape as shown in FIG. Next, as shown in FIG. 7, place the two substrates 1 and 2 in a vacuum system, and when the system reaches about 0.1 to 10 Hg, immerse the liquid crystal injection port 4 into the liquid crystal material 6 Thereafter, the system is returned to normal pressure and the liquid crystal substance 6 is introduced into the device.

Thereafter, as shown in FIG. 8, the liquid crystal injection port 4 is immersed in the liquid crystal substance 6), and the injection port base 8 is heated under pressure using an ultrasonic welder to heat-seal the film. Next, as shown in FIG. 9, the protruding part of the liquid crystal injection port is cut along a cutting line 11 that matches the line trimmed when producing the protruding part 9 to form a smooth straight line.

With the above operations, the liquid crystal display device is completed.

Next, the effects of the present invention will be explained.

According to the method according to the present invention, when the liquid crystal substance 6 is injected,
Because the liquid crystal injection port 4 of the device is protruding, the area on the outside of the device that gets wet with liquid crystal material is extremely small compared to conventional devices.
In this embodiment for watches, the density is 1/1, which leads to saving of liquid crystal material 6, and it is also possible to suppress staining and deterioration of the liquid crystal. In addition, in the conventional method, after the step of enclosing the liquid crystal substance 6, a step of washing off the liquid crystal substance 6 adhering to the outer surface of the device was required, but in the present invention, since the liquid crystal substance 6 is removed, the washing step can be omitted. It has the effect of improving efficiency.

[Brief explanation of drawings]

1 to 3 are plan views showing a conventional display device when liquid crystal is sealed, FIG. 4 is a plan view showing the device shown in FIG. 1 in a sealed state, and FIGS. FIG. 3 is a front view showing the implementation method. 1, 2...Substrate, 3...Sbaser, 4...
...Liquid crystal inlet, 5...Liquid crystal outlet, 6...
...Liquid crystal substance, 7...Sealing agent, 8...
・Protruding inlet base, 9... Protruding part, 11...
... Cutting line. Figure 2 Figure 3 Figure 4 Figure 5 Figure 0 Figure 8 Figure 0

Claims (1)

[Claims] 1 Process one of two flexible transparent plastic substrates with a transparent conductive film on them into a display electrode and the other into a counter electrode, place them facing each other, and seal the periphery by leaving a part that will serve as an injection port. In the manufacturing method of a liquid crystal display device in which liquid crystal material is injected through the injection port, the injection port portion is made to protrude, the liquid crystal material is bonded after being injected, and the protrusion portion is then cut. A manufacturing method for liquid crystal display devices.