JPH03287121A - Liquid crystal element and liquid crystal panel and production thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a method for manufacturing a liquid crystal panel.

Conventional technology A liquid crystal panel that uses light scattering that does not require a polarizing plate and is made by combining a polymer material and a liquid crystal & II oxide was proposed by FARGASON et al., and has recently been put into practical use as light control glass. ing.

゛'Nisiday International Symposium 1
6 (SID INTERNATIONAL S
YMPO3IUM XVI)” (1985) 68-
70 The liquid crystal panel has no threshold for the change in light transmittance with respect to voltage, and the shielding rate is still insufficient when light is blocked (i.e., dark state), and the light transmission is insufficient when light is transmitted (i.e., bright state). As a result, the contrast between light and dark is poor. As a method to improve these drawbacks, Horidori et al. have proposed a method in which a solution of a mixture of a liquid crystal composition and a polymeric material is dissolved in an organic solvent is prepared, and a cast film is produced from this solution (No. 15). Liquid Crystal Discussion Group (1989) 2B04). Furthermore, excellent electro-optical properties have been obtained by a method proposed by the group of Dainippon Ink (15th Liquid Crystal Symposium (1989) 2B12). That is, a mixture of a photocurable monomer and a nematic liquid crystal composition is injected between two glass substrates for liquid crystal panels with a certain gap formed in advance, and after the injection, light is irradiated through the glass substrates, and the light is This method involves crosslinking curable monomers, and by this method a liquid crystal panel that can be driven at a relatively low voltage and has good contrast has been created.

Problems to be Solved by the Invention However, the latter method has many problems when actually producing liquid crystal panels. That is, after injecting the liquid crystal,
Since this method involves irradiating light through a glass substrate, this method cannot be used if the substrate absorbs light. For example, this method cannot be used in the case of an active matrix liquid crystal panel that uses so-called (TPT (Fl film transistor)) as an electrode because TPT absorbs light and is photodegraded. If a material that can be stored away is used, for example, if a dye color filter is used for color display, the filter will deteriorate due to light irradiation.

Means for Solving the Problems In order to solve these problems, the liquid crystal element of the present invention has a liquid crystal display layer between two substrates having at least transparent electrode layers arranged facing each other at a constant distance. A structure having a spongy composition made of an organic polymer filled with organic material, characterized in that it has a thin film of an organic material on at least one transparent substrate, and when forming the spongy composition, the organic material is The present invention is further characterized by a manufacturing method in which the thin film is activated in advance and the activated surface is used to polymerize the polymerizable composition.

Effect: By using the above method, it is possible to easily prevent air bubbles from entering the liquid crystal layer, making it easy to mass-produce large-area panels with good thickness accuracy. In particular, when photocrosslinking is involved, there is no need to directly irradiate the mixture of liquid crystal composition and photopolymerizable composition on the substrate with light, so it can be effectively used in active matrix liquid crystal devices that use thin film transistors that shield light. Furthermore, even when manufacturing a liquid crystal element using a material that easily deteriorates due to light, such as a color filter, it is sufficient to activate the substrate on the side that does not have the degradable material.

Example Hereinafter, the present invention will be specifically explained using the drawings.

Example 1. As shown in Figure 2, a 200nm film was applied to the surface in advance.
ITO (indium tin oxide) transparent electrode 22 with a thickness of
A glass substrate 21 (50mm x 50m
After washing a glass film 20 nm (thick 1 inch) in a weak alkaline solution and thoroughly washing with water, a polystyrene film 25 having a dithiocarbamate end group is formed on the transparent electrode 22 using a polystyrene nitrobenzene solution to a thickness of 20 nm. Formed. This surface was activated by irradiating it with light from a high-pressure mercury lamp for 1 hour. On this activated surface, a mixture 23 (hereinafter referred to as liquid crystal/polymer mixed layer) consisting of a liquid crystal composition, a photopolymerizable composition, and a small amount of glass beads with a diameter of 10 μm is applied to bond the upper and lower substrates. Apply to the entire surface except for the peripheral area 24. (See FIG. 3, which shows the substrate viewed from above.) As a coating method at this time, a spin coater, a blade coater, offset printing, screen printing, gravure printing, etc. can be used. However, in the case of spin cord, it is necessary to wipe off the peripheral area 24 after applying the entire surface, so in this example, by screen printing, as shown in Figure 3, 15 mm was left from the periphery on one side, and 5 mm was left on the other three sides. A coating film with a thickness of 12 μm was formed on an area of 40 mm×30 mm. The liquid crystal composition used was a commercially available nematic liquid crystal with positive dielectric anisotropy (Z L l-1252 manufactured by Merck ■).
It is. Further, it is important that the polymerizable composition is a composition containing at least an acrylic monomer and a polymerization initiator, and that it is not compatible with the liquid crystal composition. In this example, Desolite manufactured by Nippon Synthetic Rubber (1) was used and 20 polymerized parts were mixed into the liquid crystal composition. The other substrate is a glass substrate 4 as shown in FIG.
1, a blue filter layer 42 is formed on top of the blue filter layer 42, a TTO transparent electrode 43 is formed on top of the blue filter layer 42, and a TTO transparent electrode 43 with a diameter of 1
A sealing resin 44 made of a photocurable adhesive mixed with a small amount of 0 μm short glass fibers was formed into a rectangular shape with a width of 0.2 mm. In this state, the two substrates are placed together under reduced pressure with the transparent electrode parts protruding in opposite directions, and the blue filter and liquid crystal parts are bonded together by irradiating light with the light shielded. The agent was photocured. A cross-sectional view of the liquid crystal panel thus produced is shown in FIG. The manufactured liquid crystal panel was initially opaque with a slight bluish tint, and when a 10 volt DC electric field was applied to it, the liquid crystal/polymer mixed layer became transparent and light was partially transmitted through the blue filter. The contrast value at this time was 13.

Example 2. As in Example 1, apply 200n on the surface in advance.
ITO (indium tin oxide) transparent electrode 2 with a thickness of m
2 formed on the entire surface of the glass substrate 21 (50 mm x 50
After cleaning the 111+11 glass (thickness: 11 ml) in a weak alkaline solution and thoroughly rinsing with water, the entire substrate was placed in a commercially available plasma polymerization apparatus, and the transparent electrode 2 was placed in a 0.1 Torr argon gas and methyl methacrylate monomer atmosphere.
2, a plasma polymerized film 25 of methyl methacrylate is placed on 10
The nm shape was used. A mixture 23 (hereinafter referred to as liquid crystal/polymer mixture) consisting of a liquid crystal composition, a photopolymerizable composition, and a small amount of glass beads with a diameter of 10 μm is placed on top of this, leaving a peripheral area 24 for adhesion of the upper and lower substrates. was applied to the entire surface.

In this example, a coating film with a thickness of 12 μm was formed by screen printing on an area of 40 mm×30 mm, leaving 15 mm from the periphery on one side and leaving 5 holes on the other three sides, as shown in FIG. The liquid crystal composition used was a commercially available nematic liquid crystal having positive dielectric anisotropy (Z L l-1844 manufactured by Merck ■). In this example, Toagosei Chemical Co., Ltd. Aroninx 3033 was used as the polymerizable composition, and 15 polymerization parts were mixed into the liquid crystal composition.

On the other hand, a display electrode section 5 consisting of a thin film transistor array and a transparent electrode is placed on another glass substrate 51 of the same size.
Similarly to Example 1, a sealing resin 54 made of a photocurable adhesive mixed with a small amount of short glass fibers having a diameter of 10 μm was formed into a rectangular shape with a width of 0.2 mm. In this state, the two substrates are pulled out from each other and arranged so that the electrode parts protrude in opposite directions, and then glued together under reduced pressure.The display electrode part 52 and the liquid crystal part are irradiated with light while being shielded from light. The adhesive was photocured. The manufactured liquid crystal panel was initially in a light-scattering state, and on the other hand, when the thin film transistor was driven, it became transparent and had a contrast value of 14.

In the examples, ultraviolet irradiation and plasma polymerization were explained as activation treatment methods, but the present invention is not limited to these, but surface ionization by contact with oxidizing or reducing materials, irradiation with radiation or electron beam , corona treatment is also effective. Furthermore, a method of plasma-treating a pre-formed organic thin film in an argon gas atmosphere is also effective.

As described above, the present invention has made it possible for the first time to manufacture liquid crystal panels that do not require polarizing plates, including active matrix panels and color-pensive matrix panels, and it has become extremely easy to manufacture large-area display panels. It becomes possible to manufacture the product at low cost.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a liquid crystal panel according to an embodiment of the present invention using a color filter, Fig. 2 is a cross-sectional view showing the manufacturing process of the present invention, and Fig. 3 is a formation of a liquid crystal/polymer mixed layer. A diagram showing the state, FIG. 4 is a sectional view showing the manufacturing process, and FIG.
11...Glass substrate, 12...Transparent electrode, 13...Glass substrate, 14...Transparent electrode , 15...Liquid crystal/polymer mixed layer, 16.
... Seal resin, 17 ... Filter layer, 18 ... Organic thin film layer.

Claims (6)

[Claims] (1) A structure having a spongy structure made of an organic polymer filled with a liquid crystal composition between two transparent substrates each having at least a transparent electrode layer arranged opposite to each other with a constant interval, A liquid crystal element comprising a thin film of an organic substance on at least one of the transparent substrates. (2) A thin film of an organic polymer is formed on at least one of the substrates on which an electrode layer is formed, and the surface of the organic polymer thin film is subjected to an activation treatment, and then the substrate and the other After arranging the substrates facing each other at a constant distance, a mixture consisting of a liquid crystal composition and a polymerizable composition is filled between the two substrates, and the activated organic polymer is filled with a mixture consisting of a liquid crystal composition and a polymerizable composition. 1. A method for producing a liquid crystal device, comprising polymerizing the polymerizable composition on the surface of a molecular thin film to form a spongy composition. (3) forming a thin film of an organic polymer on at least one of the substrates on which an electrode layer is formed; and applying an activation treatment to the surface of the organic polymer thin film; and forming a liquid crystal on at least one of the substrates. a step of applying a mixture consisting of a liquid crystal composition and a polymerizable composition; and a step of applying a mixture consisting of a liquid crystal composition and a polymerizable composition to the two substrates, the layer in which the polymerizable composition and the liquid crystal composition coexist formed on the surface of at least one of the substrates is on the inside. A method for manufacturing a liquid crystal panel, comprising the step of arranging the panels in a sandwich manner and bonding them together under reduced pressure. (4) A liquid crystal panel manufactured using the method for manufacturing a liquid crystal panel according to claim (3). (5) The method for manufacturing a liquid crystal element according to claim (2) or (3), wherein the activation treatment is performed by irradiating the surface with active energy rays. (6) A method for manufacturing a liquid crystal element according to claim (2) or (3), wherein the activation treatment is a surface plasma treatment.