JPH0756014A - Color filter - Google Patents

Abstract

PURPOSE:To provide a color filter which has detergency higher than the detergency by solvent washing, capable of washing without using a solvent and has the high adhesion property between constituting layers and excellent durability by forming a protective layer after executing a UV ozone treatment. CONSTITUTION:The red ink R, green ink G and blue ink B with which a black matrix substrate 12 formed with a black matrix 14 on a transparent substrate 13 is printed in the positions to be formed with patterns are cured to form colored layers 16 consisting of the respective colored patterns 16R, 16G, 16B on the substrate. The protective layer 18 is thereafter so formed as to cover the black matrix 14 and the colored layers 16. The protective layer 18 is formed in the regions to be formed with the protective layer after the regions are subjected to the UV ozone treatment. The UV ozone treatment is capable of removing even the contaminations of a silicon system not removable by surfactant washing of an aq. system and improves the reliability of the color filter by enhancing the adhesion property of the protective layer and the other layers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter,
In particular, the present invention relates to a color filter having high adhesion between constituent layers and excellent durability.

[0002]

2. Description of the Related Art In recent years, monochrome or color liquid crystal displays have been attracting attention as flat displays. Liquid crystal displays include an active matrix system and a simple matrix system for controlling three primary colors, and a color filter is used in each system. In the color liquid crystal display, the constituent pixel portions have three primary colors (R, G, B), and the transmission of each light of the three primary colors is controlled by electrical switching of the liquid crystal to perform color display.

This color filter is constructed by forming each colored layer, a protective layer and a transparent electrode (ITO) on a transparent substrate. Among these layers, the protective layer plays a role of protecting the colored layer from various solvent treatments in the cell assembling step and preventing impurities from being eluted from the colored layer in the liquid crystal after cell assembling. . In addition, while forming the transparent electrode (ITO) by sputtering, it withstands high temperature and stress distortion of ITO,
It is necessary that cracks and wrinkles do not occur. In addition, the protective layer has irregularities (± 0.3 to 1.0 μm) on the surface of the colored layer.
m) to cover the surface of the color filter so that the surface of the color filter has a smooth surface of ± 0.1 μm or less.

The protective layer is usually formed by diluting a photocurable or thermosetting resin with a solvent or the like and applying it by spin coating. At this time, the surface of the exposed portion of the colored layer and the surrounding glass surface must be in a clean state. If the exposed glass surface of the colored layer and its peripheral portion is contaminated before coating the protective layer, the protective layer resin diluted with the solvent during spin coating is repelled, causing pinholes in the protective layer, resulting in a protective layer. Loss of function of
The smoothness of the surface of the protective layer causes deterioration. Further, since the contamination is relatively mild, the adhesion of the protective layer to the underlying layer (the colored layer and the glass exposed portion around the colored layer) is deteriorated, and after the transparent electrode film (ITO) is formed, the protective layer suffers from stress strain of ITO. Cannot withstand, wrinkles and cracks of ITO,
The protective layer may peel off during the cell assembly process.

For this reason, before applying the protective layer,
The colored layer and the exposed glass portion around the colored layer must be completely decontaminated. Therefore, whether or not the glass substrate on which the colored layer has been formed before cleaning the protective layer has a good cleaning condition is extremely important. .

Conventionally, a solvent such as trichlene is used, and before the protective layer is formed, the glass substrate on which the colored layer is formed is subjected to ultrasonic cleaning with a solvent to remove the contamination of the glass substrate to form a color filter. .

[0007]

The cleaning power of the ultrasonic cleaning method using a solvent such as trichlene is extremely strong, and most of the contamination of the glass substrate that causes pinhole defects and poor adhesion of the protective layer should be removed. Was possible.

However, in recent years, the problem of the effect on the global environment has been highlighted, and the ultrasonic cleaning method using the above solvent, which uses a large amount of solvent and is highly likely to release the volatilized solvent into the atmosphere, is regarded as a problem. ing. Therefore, in order to meet future environmental standards and minimize damage to the global environment, at present, various solvent washings are gradually replaced with water-based surfactant washings that have less environmental impact.

However, the water-based surfactant cleaning method is far inferior in cleaning power to the solvent cleaning method, and water-insoluble oil-based stains and polymer resin-based stains cannot be completely removed, resulting in silicone-based stains. In the end, there is a problem in that cleaning cannot be performed at all, which causes pinhole defects and poor adhesion in the protective layer.

The present invention has been made in consideration of the above-mentioned circumstances, and has a cleaning power more than that of solvent cleaning, and by using no solvent, it is possible to carry out cleaning with less influence on the global environment. It is also an object of the present invention to provide a color filter having high adhesion between layer configurations and excellent durability.

[0011]

In order to achieve such an object, the present invention is provided so as to cover a glass substrate and the black matrix layer and the coloring layer formed on the glass substrate. The protective layer and the transparent electrode were provided, and the protective layer was formed after performing UV ozone treatment on the protective layer forming region.

[0012]

The protective layer provided so as to cover the black matrix layer and the colored layer formed on the glass substrate is formed after the UV ozone treatment is performed in advance. The UV ozone treatment described above can also remove silicone-based contaminants that cannot be removed by washing with a water-based surfactant. This treatment can significantly reduce the pinhole defect occurrence rate when the protective layer is formed, and also greatly improves the adhesion between the protective layer and the black matrix layer, the colored layer and the exposed glass surface around it. However, it is possible to prevent wrinkles and crack defects of ITO and prevent peeling of the protective layer during the cell assembly process. Moreover, since the solvent washing step can be eliminated, the influence on the global environment can be minimized.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an example of an active matrix type liquid crystal display (LCD) using the color filter of the present invention, and FIG. 2 is a schematic sectional view of the same. 1 and 2, in the LCD 1, the color filter 10 and the transparent glass substrate 20 are opposed to each other with a sealant 30 interposed therebetween, and a twisted nematic (T) is provided therebetween.
N) Liquid crystal layer 40 made of liquid crystal and having a thickness of about 5 to 10 μm
And the polarizing plates 50 and 51 are disposed outside the color filter 10 and the transparent glass substrate 20.

FIG. 3 is an enlarged partial sectional view of the color filter 10. In FIG. 3, the color filter 10 includes a black matrix substrate 12 in which a black matrix 14 is formed on a transparent substrate 13, a coloring layer 16 formed between the black matrices 14 of the black matrix substrate 12, and the black matrix 14 and coloring. Layer 1
Protective layer 18 and transparent electrode 1 provided so as to cover 6
9 is equipped. This color filter 10 is a transparent electrode 1.
9 is arranged so as to be located on the liquid crystal layer 40 side. The colored layer 16 is composed of a red pattern 16R, a green pattern 16G, and a blue pattern 16B, and the array of each colored pattern is a mosaic array as shown in FIG. The arrangement of the coloring pattern is not limited to this, and may be a triangular arrangement, a stripe arrangement, or the like.

Display electrodes 22 are provided on the transparent glass substrate 20 so as to correspond to the colored patterns 16R, 16G, 16B, and each display electrode 22 has a thin film transistor (TFT) 24. Further, a scanning line (gate electrode busbar) 26a and a data line 26b are arranged between the respective display electrodes 22 so as to correspond to the black matrix 14.

In the LCD 1 as described above, each of the colored patterns 16R, 16G and 16B constitutes a pixel, and the display electrode corresponding to each pixel is turned on and off in a state in which the illumination light is irradiated from the polarizing plate 51 side, whereby the liquid crystal is formed. The layer 40 operates as a shutter, and light is transmitted through each pixel of the colored patterns 16R, 16G, and 16B to perform color display.

The transparent substrate 13 of the black matrix substrate 12 constituting the color filter 10 is a rigid material such as quartz glass, low expansion glass or soda lime glass, a transparent resin film, an optical resin plate or the like. It is possible to use a flexible material having such flexibility. Among them, Corning 7059 glass is a material with a small coefficient of thermal expansion, has excellent dimensional stability and workability in high-temperature heat treatment, and is a non-alkali glass that does not contain an alkali component in the glass. It is suitable for a matrix type LCD color filter.

An example of manufacturing the color filter 10 of the present invention will be described with reference to FIG. In the example shown in FIG. 4, the black matrix 14 is first formed on the transparent substrate 13.
The red ink R is printed at the position where the red pattern 16R is to be formed on the black matrix substrate 12 on which the ink has been formed (FIG. 4A). This printing can be performed by intaglio offset printing using, for example, an intaglio having a recess corresponding to the red colored layer and a blanket.

Similarly, the black matrix substrate 1
The green ink G is printed at the position where the second green pattern 16G is to be formed, and the blue ink B is printed at the position where the blue pattern 16B is to be formed (FIG. 4B).

Next, the red ink R, the green ink G, and the blue ink B are cured to form the respective colored patterns 16R, 16R.
The colored layer 16 including G and 16B is formed on the substrate (FIG. 4C).

After the colored layer 16 is formed as described above, the protective layer 18 is formed so as to cover the black matrix 14 and the colored layer 16. The protective layer of the color filter of the present invention is characterized in that it is formed after the protective layer forming region is subjected to UV ozone treatment.

The principle of UV ozone treatment is as follows.

[0023]

[Equation 1] Oxygen radicals generated by the above reaction react with impurities on the glass substrate to exert a cleaning effect. Further, by irradiating the glass substrate with short-wavelength ultraviolet light, the impurities are excited and decomposed to accelerate the reaction with oxygen radicals.

Here, the preferable conditions for UV ozone treatment are shown below. Irradiation light spectral characteristics: Short wavelength ultraviolet rays with bright lines of 184.9 nm and 253.7 nm Irradiation light intensity: 5 to 30 mW / cm ² Irradiation time: 5 to 20 min Working gas: Oxygen, nitrogen (inert gas) mixed gas Oxygen content rate: 20 to 100% Gas flow rate: 0 to 10 ml / min Temperature: 15 to 50 ° C By such ozone treatment, wetting of the protective layer resin diluted with the solvent is improved, and the coating property of the protective layer resin during spin coating is improved. Greatly improved. FIG. 5 shows the effect of cleaning glass on the UV ozone treatment time. The respective conditions at that time are shown below.

1) UV ozone treatment conditions Spectral characteristics of irradiation light: short wavelength ultraviolet rays having bright lines of 184.9 nm and 253.7 nm Irradiation light intensity: 14 mW / cm ² Irradiation time: 0,1,3,5,10,20 min Gas used : Oxygen / nitrogen mixed gas Oxygen content: 20% Gas flow rate: 0 ml / min Temperature: 30 ° C 2) Sample glass preparation conditions Sample glass is one of the most difficult substances to remove by cleaning before UV ozone treatment. A low molecular weight siloxa (silicone)
The film formed by the following method was used.

(Conditions for Forming Silicone Film) Silicone rubber containing 8000 ppm of low molecular weight siloxane having a degree of polymerization of 4 to 20 is pressure-bonded to glass subjected to ultrasonic cleaning with solvent at a pressure of 10 kg / cm ² for 1 second to form a silicone film.

3) Method for measuring degree of cleaning by UV ozone treatment Using 2-ethoxyethanol, which is a solvent for coating a resin for protective layer (diluting solvent for spin coating), the contact angle of the sample glass is measured to clean the surface of the sample. I checked the degree. Generally, the cleaner the surface of the sample glass, the smaller the contact angle for 2-ethoxyethanol. Contact angle is 1m below the droplet
It was measured after in. By the way, the contact angle of the solvent-cleaned glass surface of the above sample before forming the low-molecular-weight siloxane film was 7 °.

As shown in FIG. 5, 5 mi under the above conditions.
By performing UV ozone treatment for n or more, the same as the glass that was washed with the solvent before the formation of the low molecular weight siloxane film.
-It can be seen that the wettability (cleanability) with respect to ethoxyethanol is obtained. However, although it cannot be seen from the graph, when the UV ozone treatment is performed for more than 20 minutes, the colored layer is damaged by UV light, which causes a defect after ITO formation. Specific examples of these will be shown later.

By the UV ozone treatment as described above, the contact angle of the protective layer resin in the protective layer forming region with the coating solvent is 7
° C or less, the coating property of the protective film resin during spin coating is improved, pinhole defects are reduced, and the protective layer after curing the protective layer resin, the underlying black matrix layer, the colored layer and the substrate glass around it Adhesion with the exposed part is improved.

The protective layer 18 is formed by using a transparent resin such as an acrylic resin, an epoxy resin or a polyimide resin (FIG. 4 (E)). The thickness of the protective layer 18 is preferably about 0.5 to 50 μm. With such a protective layer 18, the surface of the color filter 10 is smoothed, reliability is improved, and the liquid crystal layer 4 is provided.
It is possible to prevent pollution to zero.

Next, a transparent electrode (IT
O) 19 is formed (FIG. 4 (F)). This transparent electrode 19
Can form an indium tin oxide (ITO) film by a known method such as a vapor deposition method and a sputtering method, and the thickness is preferably about 200 to 2000 Å.

Next, the present invention will be described in more detail by showing specific examples. (Example) 7059 glass (thickness = 1.1 mm) manufactured by Corning Incorporated was used as a transparent substrate, a photosensitive resist having the following composition was applied on the transparent substrate by a spin coating method (rotation speed = 1600 rpm), and then At 70 ° C. for 10 minutes, and dried (prebaked) to form a photosensitive resist layer (thickness =
0.6 μm) was formed.

(Composition of Photosensitive Resist) 4.47% by Weight Polyvinyl Alcohol Aqueous Solution (Nippon Gosei Chemical Co., Ltd. Gohsenal T-330) ... 1000 parts by Weight Diazo Resin 5% by Weight Aqueous Solution (D-011 by Shinko Giken) ... 57.1 parts by weight Next, the photosensitive resist layer was exposed through a photomask (line width = 45 μm) for a black matrix. The exposure apparatus used was a proximity exposure apparatus manufactured by Dainippon Screen Co., Ltd., and the exposure amount was 50 mJ / cm ^2.
And After that, shower development was performed using water at room temperature (development time = 45 seconds), and then heat treatment (post-baking) was performed at 100 ° C. for 30 minutes to form a relief image having a line width of 45 μm for a black matrix.

Next, this transparent substrate was dipped in an aqueous palladium chloride solution (Red Schumer made by Nippon Kanigen, 5-fold diluted solution) for 4 minutes, and the relief image was used as a relief containing a catalyst.

Then, this substrate was immersed in a nickel plating solution (nickel plating solution Top Chemialoy B-1 manufactured by Okuno Seiyaku Co., Ltd.) at room temperature containing a boron-based reducing agent for 4 minutes to form a black relief, and then 200 ° C., 1 ° C. A black matrix substrate was obtained by performing heat treatment for a period of time.

Next, a colored layer was formed on the above black matrix substrate as follows. That is, plate depth 6μ
m, a plate having a stripe-shaped recess of 110 μm, and a silicone blanket, by the intaglio offset printing method, the following ink compositions S-1, S-2, S- were formed between the black matrices on the black matrix substrate.
3 was printed in this order to form a 110 μm wide stripe pattern of blue, green and red, respectively. Then, the substrate is heated at 200 ° C. for 30 minutes to thermally cure the ink composition to form a film having a thickness of 2 to 3 μm.
To obtain a colored layer of.

Ink Composition (S-1) Facial Agent-Rionol Blue ES (CIPIment Blue 15: 6) (Toyo Ink Mfg. Co., Ltd.) 14.2 parts by weight-Rionogen Violet RL (Toyo Ink Mfg. Co., Ltd. CI Pigment Violet) 23)… 0.8 parts by weight Varnish ・ Polyester acrylate resin (Toagosei Kagaku Kogyo Aronix M7100)… 52.5 parts by weight ・ Diallyl phthalate prepolymer (Daiso Co., Ltd. DAP A)… 22.5 parts by weight Monomer ・ Trimethylolpropane triacrylate Monomer: 10.0 parts by weight Ink composition (S-2) Facial agent-Rionol Green 2YS (CIPigment Green 36, Toyo Ink Mfg. Co., Ltd.): 15.0 parts by weight-Seika Fast Yellow 2700 (CIPigment Yellow 83, Dainichi Seika Co., Ltd.) )… 5.0 parts by weight Varnish and polyester acrylate resin (Toagosei Kagaku Kogyo Aronix Co., Ltd.) M7100)… 47.6 parts by weight ・ Diallyl phthalate prepolymer (Dap A Co., Ltd.)… 20.4 parts by weight Monomer ・ Trimethylolpropane triacrylate monomer… 12.0 parts by weight Ink composition (S-3) Facial agent ・ Chlomophthal red A3B (Ciba Geigy CIPigment Red 177) 16.0 parts by weight Seika Fast Yellow 2700 (CIPigment Yellow 83, Dainichi Seika Kogyo Co., Ltd.) 4.0 parts by weight Varnish, polyester acrylate resin (Aronix M7100, Toagosei Co., Ltd.) … 46.2 parts by weight ・ Diallyl phthalate polymer (Dap A Co., Ltd.) 19.8 parts by weight Monomer ・ Trimethylolpropane triacrylate monomer… 14.0 parts by weight Next, a protective layer was formed so as to cover the colored layer and the black matrix layer. ..

To form the protective layer, first, samples were prepared under the following conditions, in which the treatment time was changed to 0, 1, 3, 5, 10, and 20 min. (UV ozone treatment conditions) UV lamp: KYOKKO SGL-900HU Ozone Irradiation light Spectral characteristics: Short wavelength ultraviolet rays with bright lines of 184.9 nm and 253.7 nm Irradiation light intensity: 14 mW / cm ² Irradiation time: 0,1,3,5 , 10,20min Gas used: Oxygen / nitrogen mixed system Oxygen content: 20% Gas flow rate: 0ml / min Temperature: 30 ℃ Next, spin coat method (rotation speed = 1500rpm) with a coating solution with the composition shown below. Was applied to 6 types of samples which were subjected to the above ozone treatment.

(Composition of coating liquid for forming protective layer) -Photo-curable acrylate oligomer (o-cresol novolac epoxy acrylate (molecular weight 1500 to 2000) ... 35 parts by weight-cresol novolac type epoxy resin ... 15 parts by weight-Polyfunctional polymerization Polymerizable monomer (dipentaerythritol hexaacrylate (DPHA, Nippon Kayaku Co., Ltd.) ... 50 parts by weight-Polymerization initiator (Irgacure manufactured by Ciba-Geigy) ... 2 parts by weight-Epoxy curing agent (UVE1014 manufactured by General Electric) ... 2 parts by weight Part 2-ethoxyethanol: 200 parts by weight And, for this coating film, a broximity exposure device manufactured by Dainippon Screen Co., Ltd. was used, and the exposure amount was 15 mJ / cm 2.
^The entire surface was exposed at ² . Then, prebaking was performed at 180 ° C. for 60 minutes. The thickness of the protective layer applied under the above conditions after curing is usually 2.0 μm (without contamination).

Further, I of 0.4 μm was formed on the protective layers of the six kinds of samples on which the protective layer was formed by the sputtering method.
A TO layer was formed and samples 1 to 6 were obtained. Next, the above sample was heated at a temperature of 250 ° C. for 1 hour to perform a reliability test as a color filter. The results are shown in Table 1.

[0041]

[Table 1]

(Reliability Test Results) Table 1 shows the reliability test results. For the sample subjected to UV ozone treatment for 0 min (Sample 1), the coating liquid was completely repelled when the protective layer resin was applied by the spin coating method when forming the protective layer, and the protective layer could not be formed. This is a silicone blanket for forming the colored layer. When printing, the low-molecular siloxane of the blanket was transferred to the glass and the surface of the colored layer, forming a siloxane contamination film and drastically reducing the wettability with the coating liquid. It is presumed that this was due to what was done.

The samples subjected to UV ozone treatment for 1 min and 3 min (Samples 2 and 3), although to some extent, could not completely remove the contamination on the substrate, the coating property of the protective layer was poor, and many defects were generated. ing. Further, even in the portion where the protective layer could be applied, the adhesion between the protective layer and the underlying colored layer was poor, and as a result of the reliability test after forming the ITO film, wrinkles were formed on the ITO surface.

When the UV ozone treatment was performed for 5 minutes and 10 minutes (Samples 4 and 5), since the contamination on the substrate was almost removed by the treatment, the coatability of the protective layer was good, and the protective layer and the underlying black matrix layer were excellent. The adhesiveness to the colored layer and the exposed glass portion around the colored layer was good, and the reliability as a color filter was sufficient, so that it was put to practical use.

In the UV ozone treatment for 20 minutes (Sample 6), the contamination was sufficiently removed, so that no defect was generated from the viewpoint of coatability of the protective layer. However, the treatment time was too long, and the colored layer, which was an organic substance (acrylic polymer), was damaged by UV light and became brittle.
As a result, wrinkles of ITO were generated in the reliability test after the formation of ITO.

From the above results, under the conditions of this experiment, UV for 5 minutes or more and less than 20 minutes before the formation of the protective layer.
It was found that a color filter having a necessary and sufficient reliability can be obtained by performing ozone treatment.

[0047]

As described in detail above, according to the present invention, the protective layer provided so as to cover the colored layer and the black matrix layer formed on the substrate is formed after the UV ozone treatment is performed in advance. The above-mentioned UV ozone treatment improves the wettability between the protective layer forming region and the coating solution of the protective layer resin, and improves the adhesion between the protective layer and other layers.
The reliability of the color filter is improved. Further, the UV ozone treatment method has an extremely small effect on the global environment as compared with the conventional method in which the treatment before forming the protective layer is carried out by solvent washing, and it seems that the UV ozone treatment method can sufficiently meet future environmental standards.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of an active matrix liquid crystal display using a color filter of the present invention.

FIG. 2 is a schematic sectional view of the liquid crystal display shown in FIG.

FIG. 3 is an enlarged partial sectional view of a color filter used in the liquid crystal display shown in FIG.

FIG. 4 is a process drawing for explaining an example of manufacturing the color filter of the present invention.

FIG. 5 is a diagram showing a glass cleaning effect with respect to UV ozone treatment time.

[Explanation of symbols]

 10 ... Color filter 12 ... Black matrix substrate 13 ... Transparent substrate 14 ... Black matrix 16 ... Colored layer 16R, 16G, 16B ... Colored pattern 18 ... Protective layer 19 ... Transparent electrode

Claims (1)

[Claims] 1. A substrate, a colored layer and a black matrix formed on the substrate, a protective layer and a transparent electrode provided so as to cover the colored layer and the black matrix, and the protective layer. UV in the protective layer formation area
A color filter formed after being subjected to ozone treatment.