JPH04258902A - Production of substrate with color filter and liquid crystal display device - Google Patents

Abstract

PURPOSE:To simplify a polishing stage for a substrate with color filters. CONSTITUTION:The color filters 2 are directly formed at >=3mum thickness on the glass substrate 1 which is not subjected to polishing and thereafter, the surfaces of the color filters 2 are polished. The color filters 2, are, otherwise, directly formed on the glass substrate 1 which is not subjected to polishing and a resin layer 3 is formed at >=3mum film thickness on these filters. The surface of this resin layer 3 is then polished. The polishing of the glass substrate is omitted in this way.

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 substrate with a color filter for a large color liquid crystal display device using unpolished glass.

0002

2. Description of the Related Art FIG. 3 shows a cross section of a conventional glass substrate for color liquid crystal display. 31 is a polished glass substrate, 32
3 is a color filter, 33 is a resin layer, and 34 is an ITO film.

First, regarding the glass substrate 31, with the current production technology, the surface has a height of about 0.1 μm and a width of 1 cm.
It has minute undulations of ~2cm, making it a high quality ST.
Currently, it cannot be used for N liquid crystal display substrates unless it is polished.

[0004] Furthermore, methods for manufacturing the color filter 32 can be broadly classified into the following four types. 1) Dyeing method A mordant layer of gelatin or the like is provided on the substrate and colored in a dye bath. 2) Printing method Pigment is printed directly onto the substrate. 3) Electrodeposition method An electrode layer is provided on the substrate, and a pigment is deposited on the electrode layer in a bath bath. 4) A gel layer having micropores is provided on the sol-gel method substrate, and the dye is diffused.

However, in either method, the surface of the color filter 32 is uneven, and the surface of the color filter (35 in FIG. 3) or the surface of the resin layer thereon (36 in FIG. 3) is smooth. It has become essential to achieve display performance.

[0006] Therefore, at present, two steps are required: polishing the base glass, polishing the color filter or resin layer, and polishing.

[0007]

[Problems to be Solved by the Invention] As mentioned above, in the manufacturing method of conventional large-sized color liquid crystal display substrates, especially high-quality STN (super twisted nematic) type liquid crystal display substrates, it is difficult to solve the problem of fine particles existing in the base glass. In addition to polishing the glass itself to remove large undulations, when the glass is used to form color filters and their protective layers, fine undulations are also formed, which must be polished again to smooth them out. I had to.

An object of the present invention is to provide a method for smoothing both undulations at the same time by performing two polishing steps, which were required in the prior art, at one time.

[0009]

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and includes forming a color filter with a thickness of 3 μm or more directly on an unpolished glass substrate, and forming the color filter directly on an unpolished glass substrate. A method for manufacturing a substrate with a color filter, characterized in that the surface is polished, and a color filter is formed directly on an unpolished glass substrate, and a resin layer is formed on top of the color filter with a thickness of 3 μm or more, the resin layer The present invention provides a method for manufacturing a substrate with a color filter, which is characterized by polishing the surface.

The method of the present invention will be explained according to examples. The glass 1 in FIG. 1 is an unpolished glass having minute undulations on its surface with a height of about 0.1 to 0.5 μm and a width of about 1 cm to 2 cm.

When forming the color filter 2 or the resin layer 3, it is desirable to increase the film thickness.
It is preferable to form the film with a thickness of 3 μm or more, more preferably 10 μm or more. The forming method and material are not particularly limited.

[0012] In order to smooth the surface, the surface of the color filter or the surface of the resin layer is polished. FIG. 2 shows a schematic diagram of an Oscar type polishing machine, which is an example of a polishing machine. 21 is an upper surface plate, 22 is a glass support carrier, 23 is a buffer material, 24 is a polishing pad, and 25 is a lower surface plate. In this method, the lower surface plate 25 is rotated, and the upper surface plate 21 is in a reciprocating state and can freely rotate. A buffer material 2 is placed between the object to be polished and the upper surface plate 21.
3, and the surface to be polished is pressed against a polishing pad 24 with a constant pressure and polished.

[0013] When polishing a very soft material like the resin used this time, the processing pressure should be 10 to 80 gf/c.
A processing pressure of about 10% to 80% of that required for glass polishing is sufficient. Therefore, it is desirable to use a polishing machine that can sufficiently control the low pressure mentioned above.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a cross-sectional view of an example of a liquid crystal display device using a substrate with a glass filter manufactured by the method of the present invention. 1 is an unpolished glass substrate, 2 is a color filter, 3 is a resin layer made of acrylic resin, 4 is an ITO film, and 5 is a liquid crystal.

First, a color filter 2 is formed on an unpolished glass substrate 1 using the dyeing method described above. Next, an acrylic resin was diluted with a suitable solvent, applied, and polymerized by heating to form a resin layer 3 having a thickness of about 10 to 20 μm.

[0016] The glass substrate used here is:
The surface has a height of about 0.1 to 0.5 μm and a width of 1 cm to 2
It is unpolished glass with minute undulations on the order of cm.

Next, the surface of the resin layer 3 was mirror-finished using ultrafine alumina powder. As a polishing pad,
A very soft foamed polyurethane material was used, and polishing was performed for about 5 to 7 minutes at a polishing pressure of 50 gf/cm2.

Next, an ITO (indium-tin-oxide) film 4 was formed by low-temperature sputtering, and the substrate was observed at this point, and as a result, there was no cracking or peeling of any of the layers. Next, a desired resist film pattern is formed on the ITO film by a normal photolithography method using a positive resist, and after etching with a hydrochloric acid-based etching solution,
By thoroughly washing with water and removing the resist film, one side of the substrate constituting the liquid crystal display device was obtained.

An STN type liquid crystal panel was manufactured using the substrate thus manufactured and the substrate on which the counter electrode was formed. The alignment treatment was performed by applying a polyimide layer and rubbing. Furthermore, an STN-type liquid crystal panel was placed on top of this, with the liquid crystal molecules twisted in the opposite direction but at the same angle. Thereafter, a polarizing plate, a drive circuit section, and a light source were attached to fabricate a liquid crystal display device.

It was confirmed that this liquid crystal display device had good contrast, color reproducibility, etc., and was capable of providing sufficient full-color display.

[0021]

[Effects of the Invention] The polishing time when using polished glass and when using non-polished glass as in the present invention is only about 1 minute longer in the latter case, and the contrast is improved. The color reproducibility and the like are good, and a sufficient full color display can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an example of a liquid crystal display device using a color filter-equipped substrate manufactured by the method of the present invention.

[Figure 2] (a) is a cross-sectional view of the Oscar type polishing machine, (b)
is a plan view of the Oscar-type polishing machine.

FIG. 3 is a cross-sectional view of a conventional color filter-equipped substrate.

[Explanation of symbols]

1 Glass substrate that has not been polished 2
Color filter 3 Resin layer 4 ITO film 5 Liquid crystal

Claims (3)

[Claims] 1. A method for producing a substrate with a color filter, which comprises forming a color filter with a thickness of 3 μm or more directly on an unpolished glass substrate, and polishing the surface of the color filter. 2. A substrate with a color filter, characterized in that a color filter is directly formed on an unpolished glass substrate, a resin layer is formed thereon with a thickness of 3 μm or more, and the surface of the resin layer is polished. manufacturing method. 3. A liquid crystal display device using a substrate with a color filter manufactured by the method according to claim 1 or 2.