JPS63131103A - Color filter - Google Patents

Abstract

PURPOSE:To improve the heat resistance and smoothness of a colored film without deteriorating the spectral characteristic thereof by providing an over coating layer consisting of a specific thermosetting resin on the colored film. CONSTITUTION:The colored film 9 of a patterned shape and the over coating layer 8 are successively laminated on a substrate 10 consisting of glass, etc. The layer 8 is formed of the thermosetting resin which has >=200 deg.C heat generation peak temp. on curing by crosslinking and does not lose its transparency even after curing. A melamine resin, epoxy resin or resin mixture composed thereof is preferably used for said resin. Then, the heat resistance of the film 9 is improved without deteriorating the spectral characteristic of the films 9 and, therefore, the wrinkling and cracking of the film 9 are prevented even if a transparent conductive film 7 and an oriented film 6 are formed on the layer 8. Since the surface of the layer 8 is smoothed, a cell gap is uniformized.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is applicable to colored patterns on a substrate such as glass. The present invention relates to color filters used in liquid crystal display devices.

<Prior art> Liquid crystal color display panel etc. odor ℃, three primary colors of blue IB), green (0, red IRI) on the substrate?Colored liquid @ in the center?Prepared in a desired pattern?Used as a color filter. The structure of a liquid crystal color display panel is shown in Figure 1, and the characteristics required for a color filter are shown below.

The substrate 10 is a film such as glass or PET,
In the case of glass, those with a low concentration of alkali ions are good in terms of reliability. On top of this, a colored film 9 of 10 μm to 5.0
00μm wide stripe or 10μfiXIQμm
A color filter pattern consisting of dots of ~5,000 .mu.fi x 5,000 .mu.m is formed by a patterning technique such as photolithography or printing. The transparent conductive pattern 7 is made of ITO, In203, or the like, and is formed by sputtering or the like. Depending on the drive method, patterning may also be performed. Orientation Pattern 4.6: 1 Normally, in the case of polyimide-based 1 fat, it is better to use a temperature as close to 350° C. as possible for thermosetting.

As described above, the subsequent steps of the color filter include curing of the transparent conductive pattern 7, curing and rubbing of the ℃ orientation film 6.

Conventional color filters are polarized by sputtering in the post-process and become transparent at 4°C to 7°C. During formation, or after the formation of the transparent conductive material 7, the alignment film 6 is applied and when the colored film 9 is cured by heat, wrinkles, cracks, etc. occur in the colored film 9, and the transparent 4-layer pattern 7 is cracked and disconnected? The temperature was high.

The material of the colored film 9 of the color filter itself varies depending on the patterning technology.For example, is it a dye? The photophosphorography method used uses natural proteins such as gelatin, while the printing method uses pigments and fat. This is the main ink. 5. Are pigments usually organic? Do you use an anthraquinone type for the red color, copper phthalocyanine type for the blue color, etc.? use In this way, a thin film of a hard inorganic material such as ITO (transparent '44 [7) ff 0.1 μm to 0.3 μm is formed on the colored film 9 made of an organic material. , the hard thin film could not follow the contraction.

It is thought that wrinkles and cracks may occur.

If the drive method of the liquid crystal panel is an XY matrix type, what is the resistance value of the transparent 4-layer pattern 7? A display with good CW characteristics by lowering it? %ru. A transparent conductive film with a low resistance of 10 to 20 Ω/7 can only be obtained by sputtering while heating to about 200°C. Is this temperature an organic material? The temperature conditions are quite harsh for the color filters used, and with conventional color filters, wrinkles and cracks appear on the entire surface after sputtering, and the color filters are not sealed at ℃. It turned out to be completely useless and I was so disappointed.

Another problem is that a phenomenon occurs due to the unevenness of the color filter.

Due to the unevenness of the color filter, the cell gear knob may become uneven, the electric field applied to the liquid crystal layer 5K, and the thickness of the liquid crystal itself may vary. This results in a panel that lacks pressure uniformity and heats up at ℃. Furthermore, during rubbing of the alignment film, the orientation angle may not be uniform, and the GL crystals may rise unevenly. Such surface irregularities are noticeable in color filters whose patterning method is a printing method, and there are cases where one level difference is as much as 1.5 μm.

In this way, if the surface of the color filter is not flattened, the performance of the LCD panel and various degrees Celsius will be affected? It will cause deterioration.

Is the color filter odor °C inconvenient? In order to solve the problem, conventionally, polyimide resin or acrylic resin was coated on the colored damage, which caused wrinkles and cracks. Prevention and smoothness? I was trying to get it.

(Problems to be solved by the invention) However, do wrinkles and cracks occur with polyimide resins and acrylic resins? It was not possible to prevent it completely.

Regarding polyimide resin odor C, wrinkles and cracks are suppressed to some extent during transparent conductive sputtering while heating at 200℃, but wrinkles and cracks still occur at the pattern boundaries and edges, and disconnections occur. ? I was inducing it. Characteristics of polyimide resin: Color filters are unstable in temperature and humidity, and lack shelf life. Another drawback was that the resin was difficult to handle for mass production.

Furthermore, the price of polyimide-based resins has become extremely high.

I couldn't get rid of the acrylic resin smell (it'!, wrinkles and cracks?).This...

This is because the acrylic resin itself has poor heat resistance, and the hardness after thermosetting is 28-HB in terms of hardness, which is lower in °C hardness than that of the transparent 4-layer model.

Also, some acrylic resins turn yellow when cured under heat, which may affect the spectral characteristics of color filters, temperature retention, and blue color. Give that peak value? There were also problems that made it worse.

Kumanton? Means for Solving> The present inventor has proposed a color filter in which a patterned colored film is formed on a substrate at 200 °C.
The heat resistance and smoothness of color filters can be improved by overcoating a thermosetting resin that has a crosslinking curing exothermic peak temperature of C or higher and does not lose its transparency when cured. What to improve?Heading ℃
We have arrived at the present invention.

<Detailed Description of the Invention> The overcoat layer used in the color filter of the present invention has a crosslinking curing exothermic peak temperature of 200°C or higher;
Is it transparent when cured? It is made of a thermosetting resin that does not lose its properties, specifically melamine resin, epoxy resin alone, or a mixed set of melamine resin and epoxy resin.
I can give an example of a'. The fact that these thermosetting resins have a crosslinking cure exothermic peak temperature of 200°C or higher means that they are heat resistant to temperatures around 200°C. In other words, in practical terms, 200
Under a heated atmosphere of around °C (temperature slightly lower than the crosslinking curing exothermic peak temperature), discoloration phenomena such as yellowing do not occur, and transparency is maintained. means.

Therefore, the color filter of the present invention satisfies the physical properties required for color filters for liquid crystal color display panels.

<Effects of the Invention> The present invention provides an oat coating layer of a color filter.
Does it change color when cured? A thermosetting resin that can withstand high temperatures of 200℃ without causing any damage? Since it has been adopted, it is heat resistant without deteriorating its durability. Is it possible to improve the transparent conductive film and alignment film on the color filter? Does the hair form wrinkles and cracks? I was able to prevent it. In addition, since the surface of the color filter is smoothed, the temperature and cell gradient are made uniform, and there is no difference in the thickness of the liquid crystal 1 itself and the electric field applied to the crystal, depending on the location. It has the effect of providing a liquid crystal display with uniform pressure, etc.

<Example 1> Dry offset ink (product name: Dry Ocolor manufactured by Inu Nippon Ink ■)'5f was produced using a dry offset printing machine.
Three colors of red, blue, and green were formed on a C4-inch glass substrate according to a stripe pattern with a line width of 150 μm.

Transparent epoxy resin (yuka shell npJ product name Ebiko)
1004) Dissolve 1 part in 1 part of Petylseronlupe at ℃ as a solvent and coat with oats using a spinner? provided. Viscosity is 40cp, spinner rotation speed 1.50Orpm
, spin time 60 seconds, heat curing at 200°C for 2 hours,
The film thickness was 2.0 μm.

This color filter is made of snow ivy at room temperature.
Q/(,r/l) was imitated with ITO, and then a polyimide alignment film (part name LX manufactured by Hitachi Chemical Co., Ltd.) was printed to a film thickness of "C5, OO'Oλ" by flexographic printing.

Heat curing at 200°C for 2 hours? went. No wrinkles or cracks occurred. Moreover, the unevenness of the film surface, which was t&1 μm when printing one colored film, was reduced to 0.5 μm and was smoothed.

Epoxy resin has excellent heat resistance, between 200℃ BIR and 2
The attenuation of spectral transmittance at 450 nm at 20°C for 1 hour is 5
It is within %. Usually, acrylic resin etc. undergo so-called discoloration due to heat. The curing lecture is dense because it crosslinks in three dimensions. It also has good adhesion to glass substrates, and very good results were obtained in the seven-dimensional table peel test. In addition, it is used as an insulating material in many 4-wire devices such as printed wiring boards, and has extremely high resistivity.
It has a height of 1014Ω·α or more, and its chemical resistance is reliable.

<Example 2> Using an intaglio offset printing machine, a stripe with a line width of 150 μm was printed on a 4-inch glass substrate using a pigment-type ink using a ℃ epoxy resin (Yuka Shell (Kiki Co., Ltd. Epicoat 1004) as the vehicle). Print 3 colors in the order of ℃, blue, green, and red according to the pattern, and print at 200℃ 4
hardened over time. 1 part of petroleum solvent (Nippon Kagaku ■Weir brand name Fine Okinkol 180"), 1 part of transparent melamine cut resin (Mitsui Toatsu @ Momo brand name Suimeru 350)?Overcoated with a spinner?Applied.Viscosity is 30
When the spinner rotation speed was 1.00 rpm and the spin time was 60 seconds, the film thickness was 2.2 μm. 7A curing was performed at 225°C for 2 hours. the result,
The irregularities on the film surface were as low as 0.8 μm, compared to 1.5 μm, which is characteristic of color filters formed using buttering technology using an intaglio offset printing method.

This color filter is made into a transparent conductive turtle pattern by heating sputtering at 200°C and is made of C15Ω/crIt ITO pattern. However, no wrinkles or cracks were observed in the color filter.

The cured product of melamine (sealing resin) becomes a polymer with a three-dimensional network structure, and does not melt under heat of about 200℃,
It begins to decompose at C. Spectral transmittance characteristics: °C is 250
When heated for 2 hours at ℃, the transmittance at 450 nm is attenuated by 5%, making it extremely heat resistant.

Representative melamine resin <Example 6><Example112> Odor °C Overcoat material'r <Example 1
A mixed steel plate of the epoxy resin of 〉〉 and the melamine resin of 〈Example 2〉. 1 part of epoxy fallen fat, 2 parts of melamine garden fat,
5 parts of Petylceron Lube in solvent-bound °C? Mixed and overcoated onto the colored film using a spinner. The viscosity was 35 cp, the spinner rotation speed was 2.00 Orpm, and the spin time was 60 seconds. As a result, an overcoat layer of 2.0 μm was obtained, and the 1.5 μm unevenness characteristic of patterning by intaglio offset printing was reduced to 0.8 μm.

A transparent conductive pattern was formed on this color filter by heating sputtering at 200°C, and an ITO pattern of 15Ω/c7ft was formed on this color filter. However, no wrinkles or cracks were observed in the color filter.

〈Example 2〉 Is the odor °C as resistant to light as a wrinkled fist crank? However, melamine resin is somewhat lacking in adhesion. For example, when the product was immersed in a super wave cleaning bath for 10 minutes using a weak alkaline detergent such as Dibosch, peeling of the overcoat pattern was observed in some parts. But epoxy resin? By mixing, the adhesion was increased and ultra-sweat wave cleaning became possible for 30 minutes. What is the mixing ratio of epoxy resin and melamine resin?

It is determined by the adhesion and the temperature during heating sputtering.

[Brief explanation of the drawing]

Figure 1 is an example of a nightwear color display, which is one use of the color filter of the present invention. 11HII...1 light plate (2)lα...substrate +3
1 f7)...Transparent 4 or pattern (4'r!6)...Alignment film (5)...Liquid crystal (8)...Overcoat layer (9)...Colored film

Claims (2)

[Claims] (1) In a color filter in which a patterned colored film is formed on a substrate, the colored film is heated at 200°C.
A color filter characterized by laminating an overcoat layer of a thermosetting resin that has a crosslinking cure exothermic peak temperature as described above and does not lose transparency when cured. (2) The color filter according to claim 1, wherein the thermosetting resin is a melamine resin, an epoxy resin, or a mixed resin of a melamine resin and an epoxy resin.