JPH0210921B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a liquid crystal panel, and more particularly to a method for treating a transparent conductive film to prevent it from becoming conspicuous.

In conventional liquid crystal panels, the refractive index of the substrate, liquid crystal, and transparent conductive film is different, which causes the transparent conductive film to stand out (glare or look a little dark).
This had the drawback of significantly impairing display quality. As a means to solve this drawback, it is possible to prevent the transparent conductive film from becoming noticeable by coating the substrate or the transparent conductive film with a transparent insulating film having a refractive index between that of the substrate and the transparent conductive film to a predetermined thickness. is known. An organic metal thermal decomposition method is excellent as a treatment for preventing such a transparent insulating film from becoming conspicuous. In this case, the method of dipping the substrate in an organic solvent containing an organic metal and pulling it up at a constant speed is superior in terms of film uniformity, workability, and cost. However, it had the disadvantage that it was coated with a transparent insulating film, making the entire panel a little dark. The reflectance of the back surface that does not come into contact with the liquid crystal (average reflectance corrected for visibility) reaches about 2 to 3% when it comes into contact with air. Also, even if the polarizing plate is attached with an adhesive (n≒1.5), the
It reaches 1%. Without such an insulating film, reflections between the substrate and the adhesive are negligible.
This is because the substrate n≒1.5 and the adhesive n≒1.5. Therefore, it is desirable that such a transparent insulating film having a refractive index between that of the substrate and the transparent conductive film be coated only on the side that is in contact with the liquid crystal. As a result of various studies to solve this drawback, it was found that coating with fluororesin is an excellent method for forming a single-sided mask. When coating by dipping, it is a prerequisite that the material does not get wet. PVA
This is because, when using such ink, the organometallic film formed on the ink re-adheres to the substrate during thermal decomposition. Possible methods for coating with such a fluororesin include vapor deposition, spraying, roll coating, brush coating, screen printing, and offset printing. Fluorine-based resins include F resin (Teijin trademark), Teflon (DuPont trademark),
Examples include fluorine-based surfactants and FX liquid (trademark of Sumitomo 3M). If the thickness is at least a monomolecular layer, it will meet the objectives of the present invention.

Further, the present invention can also be applied to cases in which a transparent insulating film is coated over a transparent conductive film to prevent the transparent conductive film from being noticeable. At this time, it is necessary to avoid covering the terminals and upper and lower conductive parts, but in this case,
It was found that fluorine-based resins are superior. In any case, the present invention allows only the necessary parts to be placed on the board.
It has been discovered that fluororesin is excellent as a masking agent when coating by the organic metal immersion constant velocity pulling method.

The substrate used in the present invention may be made of glass (soda glass, borosilicate glass, etc.), ceramic, plastic, etc. as long as at least one of the opposing substrates is transparent. Depending on the case, these may be used in combination. The transparent insulating film formed on this substrate is preferably a mixture of silicon oxide and titanium oxide, and the refractive index can be adjusted between 1.45 and 2.3 by changing the molar fraction. Film thickness is 100Å to 3000Å, preferably
The refractive index ranges from 200 Å to 1500 Å, and for the purpose of preventing the transparent conductive film from standing out, there are appropriate values and ranges depending on the refractive index. The smaller the refractive index, the larger the film thickness, and the larger the refractive index, the smaller the film thickness. Such mixed insulating coatings are made by dipping the substrate in an organic solvent containing each organic metal, then pulling it up at a constant speed, drying it at 50 to 200℃, and then thermally decomposing it within the heat resistance range of the substrate at 300 to 600℃. let The organic metals include alkoxy metals, chelates, acylates, etc. of silicon and titanium, and one or more types thereof, and in some cases, different types of silicon and titanium may be selected and used.

The present invention will be explained below with reference to Examples.

Example 1 (See Figures 1 and 2) Fluorine resin 2 was coated on one side of borosilicate glass 1.
As a solution, a 0.5% acetone solution of F resin (manufactured by Teijin) was sprayed. (Figure 1-1) After curing at 100°C, it was immersed in an organometallic liquid having the following composition.

Isopropyl alcohol 100 parts Tetrabutoxysilane 10 parts Tetraoctyloxytitanium 20 parts Acetylacetone 10 parts Hydrochloric acid 6N 1 part After pulling at a constant speed of 10 cm/min, cure at 120°C for 15 minutes (Figure 1-2), and then heat to 500°C. Baking was performed for 1 hour (Figure 1-3). When pulling at a constant speed,
The surface coated with F resin was not wetted by the above liquid at all. Furthermore, during the thermal decomposition at 500°C, the fluororesin 2 was also thermally decomposed, leaving no trace at all. Organometallic coating 3 was approximately 700 Å and had a refractive index of 1.75.

Next, tin oxide was coated with a thickness of 400 Å on the organometallic coating film 3 as a transparent conductive film 4 using the CVD method (Fig.
4). After a prescribed photo process, patterning was performed using Zn-HCl (Figure 1-5). Using two such substrates as shown in Figure 1-5, they were treated with a silane coupling agent and then rubbed in a certain direction with a cotton cloth to assemble a FETN type liquid crystal display panel as shown in Figure 2. 5 is a TN liquid crystal, and 6 is a seal using an epoxy adhesive, which includes a 10 μm alumina gapping agent. In the liquid crystal panel shown in FIG. 2, the transparent conductive film 4 was not noticeable at all. Also board 1
The brightness was further increased compared to the one in which both sides were coated with Coating 3.

Comparative Example 1 When polyvinyl alcohol is used instead of fluororesin, when it is immersed in an organic metal solution and pulled up at a constant speed, the organic metal is also coated on the polyvinyl alcohol film and reattached to the substrate 1 during thermal decomposition, resulting in a clean I couldn't get the appearance.

Example 2 (See Figures 3 and 4) An indium oxide transparent conductive film 4 doped with 5% tin oxide was formed on the same substrate 1 as in Example 1 using a 200 Å vapor deposition method (see Figure 3-1). ). After a prescribed photo process, buttering was performed using HCl as shown in Figure 3-2. Fluorine-based resin 2 made of FX liquid (manufactured by Sumitomo 3M) was applied by brush to the upper and lower conductive parts 7 and lead parts 8 (after selective masking), 4 and the back side of the board, which is the opposite surface. figure-
3). Next, it was immersed in a liquid containing the following organic metal.

Atron NSi: 10 (manufactured by Nippon Soda) 80 parts Atron NTi: (manufactured by Nippon Soda) 20 parts Pulled up and applied at a constant speed of 15 cm/min (Fig. 3)
4). After drying at 60°C, it was thermally decomposed at 500°C for 1 hour. When cooled, the structure shown in Figure 3-5 was obtained. The fluororesin 2 was thermally decomposed and there was no trace of a compound. A liquid crystal panel (see FIG. 4) was assembled in the same manner as in Example 1 by combining two such substrates. Reference numeral 9 is a silver paste, which functions as vertical conduction. The liquid crystal panel shown in Figure 4 has a transparent conductive film 4 compared to conventional products.
was not noticeable at all, and was brighter than the one in which the transparent insulating film 3 was formed on both sides of the substrate 1. Furthermore, since the conductive film 4 is coated with the insulating film 3, the current consumption of the panel is reduced by about 30%. Furthermore, the level difference between the transparent conductive film 4 and the substrate 1 is reduced, and this is particularly noticeable at the edge portions of the transparent conductive film 4, so that the domain during lighting is reduced.

The liquid crystal panel with the structure shown in Figures 2 and 4 is
In addition to FETN mode, GH, phase transition type GH,
LCD display modes such as DSM, DAP, other EL,
It can also be applied to EPID, EL, colloidal light valves, etc. The liquid crystal display element using the present invention is used in watches, calculators, etc., and the display quality is much better than before.

As described above, according to the present invention, a transparent insulating film can be easily formed at necessary locations on a substrate.
Furthermore, since the immersion constant velocity pulling method is used, a large amount can be processed at one time, and therefore a manufacturing method with high mass productivity can be provided. Furthermore, since an organic solvent in which organosilicon and organotitanium were dissolved was used, it is possible to adjust the refractive index of the transparent insulating film.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing each manufacturing process of a substrate according to Example 1 of the present invention. FIG. 2 is a sectional view of a liquid crystal panel according to Example 1 of the present invention. FIG. 3 is a cross-sectional view showing each manufacturing process of a substrate according to Example 2 of the present invention.
FIG. 4 is a sectional view of a liquid crystal panel according to a second embodiment of the present invention. 10, 11...Polarizing plate.

Claims (1)

[Scope of Claims] 1. On one surface of a substrate or on a transparent conductive film formed on the surface, the transparent conductive film has a refractive index intermediate between the refractive index of the transparent conductive film and the refractive index of the substrate. In a method of manufacturing a liquid crystal panel in which a transparent insulating film is formed to prevent the conspicuousness of a conductive film, the other surface of the substrate and any part of the one surface are coated with a fluorine-based resin, and an organosilicon and applying an organic solvent in which organic titanium is dissolved onto the substrate by a dipping constant velocity pulling method, and then forming the transparent insulating film by heat treatment and thermally decomposing the fluororesin. A manufacturing method for liquid crystal panels. 2. The method of manufacturing a liquid crystal panel according to claim 1, wherein the fluorine-based resin is coated on the upper and lower conductive parts and/or the lead parts.