JPH065204A - Color filter forming method for plasma display base - Google Patents

Abstract

(57) [Summary] [Purpose] To form a color filter for a plasma display substrate that has excellent heat resistance, no gas emission, and satisfactory film thickness uniformity, resolution, and processing accuracy. A patterning portion 2a is formed by a coating step of coating a photosensitive resin composition 2 on a substrate 1 such as glass on which a color filter is to be formed and drying it, and by exposing through a mask M of a color filter pattern. An exposure step, a development step of removing the non-patterned portion 2b by development, an impregnation step of impregnating the patterned portion 2a with a colorant composition in which a heat-resistant colorant is dispersed or dissolved, and an organic component by firing. A color filter is formed by a burning step of burning out to form a filter portion on the substrate. As the colorant, heat resistant pigment, colored glass,
Materials that exchange alkali ions in the substrate glass for colored ions can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a color filter for a plasma display substrate which constitutes a plasma display panel (hereinafter abbreviated as PDP).

[0002]

2. Description of the Related Art FIG. 1 shows a conventional DC having a reflection type phosphor screen.
1 shows an example of the configuration of a type PDP, in which a flat plate-shaped front plate 11 and a rear plate 12 made of glass are arranged in parallel and opposite to each other, and a constant distance is provided by a cell barrier 13 provided therebetween. Held in. Further, a plurality of line-shaped anodes 14 parallel to each other are formed on the back surface of the front plate 11, and a plurality of line-shaped cathodes 15 parallel to each other are formed on the front side of the back plate 12 orthogonal to the anodes 14. Is formed. Further, a fluorescent layer 16 is formed adjacent to the inner surface of the cell barrier 13, and the fluorescent layer 16 has fluorescent light of red (R), green (G), and blue (B) emission colors for each cell 17. The bodies are arranged in a predetermined pattern.

In the above conventional DC type PDP, a front plate 11 and a back plate 12 are formed by applying a predetermined voltage from a DC power source between the anode 14 and the cathode 15 to form an electric field.
Each cell 1 as a display element composed of a cell barrier 13 and a cell barrier 13.
Discharge is performed inside 7. Then, the ultraviolet rays generated by this discharge cause the fluorescent layer 16 to emit light, and the observer visually recognizes the light transmitted through the front plate 11.

FIG. 2 shows an example of the structure of a conventional AC type PDP having a reflection type fluorescent screen.
Similarly to the DC type PDP described above, a flat plate-shaped front plate 21 and a rear plate 22 made of glass are arranged in parallel and opposite to each other, and both are fixed by a cell barrier 23 provided therebetween. Holds at intervals. An electrode 24 for writing is formed under the cell barrier, and electrodes 26 and 27 are formed in parallel on the back side of the front plate 21 so as to correspond to each pair of cells 25, and further on the back side thereof. A dielectric layer 28 and a protective layer 29 are formed, and a fluorescent layer 30 is formed on the inner surface of the cell barrier 23 and the front surface side of the back plate 22.

In the conventional AC type PDP, a predetermined voltage is applied between the pair of electrodes 26 and 27 formed on the front plate 21 by an AC power source to form an electric field.
Discharge is performed in each cell 25 as a display element between the front plate 21, the rear plate 22, and the cell barrier 23. Then, the ultraviolet rays generated by this discharge cause the fluorescent layer 30 to emit light, and the observer visually recognizes the light transmitted through the front plate 21.

[0006]

By the way, various improvements have been made so far in the color PDP as described above.
However, the current situation is that the contrast is not sufficient because the brightness of the PDP is not sufficient.

To make the display easier to see, it is effective to reduce the reflectance and improve the contrast.
As a means for realizing this, the front plate has an ND (Neutral Dencity) filter characteristic. Nd ₂ O ₃ is put in the front plate so as to have absorption characteristics in regions other than the main spectrum of the luminescent material. Fill the area other than the fluorescent layer with a low-reflection material. That is,
Form a black matrix. The pigment is mixed in the fluorescent layer. A pigment layer is formed before the fluorescent layer. A color filter that transmits only a single wavelength of the emission spectrum is provided for each cell of red, green, and blue. However, unlike a CRT, a PDP has little margin in brightness, and therefore a color filter with a black matrix is effective for minimizing the decrease in brightness and increasing the contrast. In the color PDP, it is necessary to provide these inside the front plate in view of the viewing angle. However, for this reason, it is required that the substrate should withstand a high temperature of about 450 to 600 ° C. or higher and that no gas is emitted in the process of producing the substrate. In this respect, the color filters currently used for liquid crystal display devices cannot be used as they are.

[0008] On the other hand, a method of forming a color filter by screen printing by forming a material into a paste is known, but it is not always satisfactory in terms of film thickness uniformity, resolution, and processing accuracy, especially when considering an increase in size. Not going.

The present invention has been made in view of the above background, and is a color filter which is excellent in heat resistance, has no gas emission, and has satisfactory film thickness uniformity, resolution and processing accuracy. It is an object of the present invention to provide a method for forming a color filter for a plasma display substrate, which is capable of forming a film.

[0010]

In order to achieve the above object, a method for forming a color filter for a plasma display substrate according to the present invention comprises applying a photosensitive resin composition onto a glass substrate on which a color filter is to be formed. And a drying step, and an exposure step of forming a patterning portion by exposure through a color filter pattern mask,
A development step of removing the non-patterned portion by development, an impregnation step of impregnating the patterning portion with a colorant composition in which a heat-resistant colorant is dispersed or dissolved, and an organic component is burned off to form a substrate. It is characterized by comprising a firing process for forming a filter portion.

When forming a color filter composed of portions having different transmission wavelengths, the above-mentioned coating step, exposure step, and exposure step for each colorant composition containing a plurality of colorants having different transmission wavelengths, respectively. By repeating the developing step and the impregnating step and then performing the baking step, the filter portion in which each color is selectively arranged may be formed on the substrate.

Further, in the case of forming a black matrix, the same steps may be added to a colorant composition containing a heat resistant black colorant.

The coating step is preferably performed by doctor blade coating, and the exposure step is preferably performed from the surface opposite to the coating surface of the glass substrate.

As the colorant used in the above-mentioned forming method, a heat resistant pigment or colored glass can be used, and further, a material for exchanging alkali ions in the substrate glass with colored ions can also be used. it can.

[0015]

According to the method for forming a color filter for a plasma display substrate of the present invention described above, the patterning portion of the photosensitive resin composition formed by the photolithography method is impregnated with the colorant composition, so that the film thickness is uniform. A color filter excellent in resolution and processing accuracy is formed. In addition, the organic component is burned out by the firing process, and a color filter without emission gas is formed.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings.

3 and 4 are process diagrams of a method for forming a color filter for a plasma display substrate according to the present invention.

First, as shown in FIG. 3A, the flat substrate 1 made of glass or the like is washed to determine the filter forming surface. Here, when using a glass substrate or the like formed by the float method, it is necessary to select whether the glass surface is a tin surface or a non-tin surface depending on the colorant used. That is, when the tin surface is used, tin ions may enter the glass and have an adverse effect depending on the type of colorant used, and as a colorant, a material that exchanges alkali ions in the substrate glass with the color ions. In the case of using, the tin surface is more likely to be ion-exchanged and the color is often improved.

Next, in the step shown in FIG. 3B, the entire surface of the substrate 1 on which the color filter is to be formed is coated with the photosensitive resin composition 2 and dried. As a coating method,
Any coating method such as a spray method, a spinner method, a dipping method, a printing method, a blade coater method, a roll coater method can be adopted.

Subsequently, in the step shown in FIG. 3C, pattern exposure is performed through the mask M of the color filter pattern to form the patterned portion 2a of the photosensitive resin composition 2. At this time, although the pattern shape is slightly inferior, exposure from the surface opposite to the coating film surface improves the adhesion and the film thickness uniformity.

Next, in the step shown in FIG. 3D, the non-patterned portion 2b is removed by development, and then the patterned portion 2a is dried to harden it.

Subsequently, in the step shown in FIG.
Coloring is performed by impregnating the patterned portion 2a with a colorant composition prepared by dispersing or dissolving a heat-resistant colorant in a solvent that can be impregnated in the photosensitive resin composition 2, and drying to harden the film. Form part 3.

In the case of a three-color filter, red,
For the colorant composition in which the colorants having the transmission wavelengths of green and blue are respectively dispersed or dissolved, the coating process of FIG. 3B to the impregnation process of FIG. 4E are repeated.
Furthermore, when a black matrix is added, the same steps are performed for a colorant composition containing a heat-resistant black colorant. As a result, as shown in FIG. 4 (f), the colored portions 3 (R), 3 (G), 3
(B) and the black colored portion 4 are arranged in a desired pattern.

Finally, the substrate 1 is transferred to a firing step and fired at a temperature sufficient for the coloring reaction to burn off the organic content remaining in the colored portion. Through the above steps, in the case of a three-color (R, G, B) color filter containing a black matrix, a filter portion 5 and a black matrix 6 having a pattern as shown in FIG. To form a color filter.

As described above, patterning is performed with the photosensitive resin composition, and the patterned portion is impregnated with the colorant composition in which the heat-resistant colorant is dispersed or dissolved, followed by firing. High uniformity,
A color filter having excellent resolution and dimensional accuracy can be formed. Further, by passing through the firing step, it is possible to burn off the organic components that cause the outgassing. At this time, depending on the colorant, it can be expected that the adhesiveness is increased and the color reaction is accelerated.

As the colorant used in the present invention, any heat-resistant pigment can be used. In this case, heat resistance of about 450 to 600 ° C. is sufficient, depending on the manufacturing process of the substrate. Further, it is also possible to use a colored glass which can ensure wavelength selectivity with a thin film thickness, a material which exchanges alkali ions in the substrate glass for colored ions, and the like. Further, it is also effective to mix a glass frit having a low melting point in order to improve color development and stability, heat resistance, adhesion and surface smoothness.

There are many kinds of heat-resistant pigments, but typical examples are iron (red), manganese aluminate (pink), gold (pink), antimony-titanium-chromium (orange), iron. -Chromium-zinc system (brown), iron system (brown), titanium-chrome system (yellow-brown), iron-chrome-zinc system (yellow-brown), iron-antimony system (yellow-brown), antimony-titanium-chromium system (Yellow), zinc-vanadium (yellow), zirconium-vanadium (yellow), chromium (green), vanadium-chromium (green), cobalt (blue), cobalt aluminate (blue), vanadium- There are zirconium-based (blue), cobalt-chromium-iron-based (black), and the like, and it is also possible to mix these and adjust the color tone. It is desirable that particles having a particle size of 1 μm or more account for 10 wt% or less of all particles. That is, if there are many particles having a large particle diameter, the transmittance is lowered and the luminance is lowered. Further, the particle size is 0.01 to
It is desirable that 0.7 μm particles account for 20 wt% or more of all particles.

There are many kinds of colored glass due to the coloring mechanism. Even with the same raw material, the color changes depending on the conditions. As an example, frit is made of silicic acid (SiO ₂ ), lead oxide (Pb).
O), potassium oxide (K ₂ O ₅ ), boric acid (B ₂ O ₃ ),
The main component is potassium lead glass containing aluminum fluoride (AlF ₃ ), arsenic oxide (As ₂ O ₃ ), etc., and the raw materials are silica stone, red lead, yellow lead oxide, white lead, potassium nitrate, boric acid, borax. ,
Sodium bicarbonate, fluoride, etc. are used. Arsenous acid (white), tin oxide (white), copper oxide (green), cobalt oxide (blue), potassium dichromate (yellow), antimony oxide (yellow), iron oxide (brown), manganese dioxide as a coloring agent. (Purple), nickel oxide (purple), gold chloride (red), sodium uranate (orange), selenium red (red-red), etc. are combined and mixed. Then, these are mixed, heated and melted, vitrified, and cooled and ground to be used.

As a typical material for exchanging alkali ions in the substrate glass for colored ions, red (5 to 40 parts by weight of copper sulfate, 40 to 90 parts by weight of alkali metal salt, 5 to inorganic fillers) is used. 55 parts by weight), green (copper sulfate 40 ~
90 parts by weight, alkali metal salt 40 to 90 parts by weight, inorganic filler 5 to 20 parts by weight), blue (cobalt sulfate 40 to 80 parts by weight, alkali metal salt 40 to 90 parts by weight, inorganic filler 5
˜20 parts by weight) and the like can be used.

Here, the alkali metal salts include lithium sulfate, sodium sulfate and potassium sulfate as alkali metal sulfates, and zinc sulfate, calcium sulfate, magnesium sulfate and barium sulfate as one or two kinds as alkaline earth metal sulfates. The above mixture is used. It is considered that these are mainly melted on the glass surface to improve the adhesion to the glass substrate surface and enhance the ion exchange.

The inorganic filler is considered to have the functions of preventing shrinkage of the melt during firing and controlling the shade of the colored color, and various heat-resistant inorganic substances can be used. For example, alumina (Al ₂ O ₃ ), titanium oxide (T
iO ₂ ), zircon (ZrO ₂ ), zirconium silicate (ZrSiO ₂ ), calcium carbonate (CaO ₂ ), iron oxide (Fe ₂ O ₃ ) and the like can be used. If necessary, 1
Parts by weight or less of silver salt (AgNO ₃ , Ag ₂ O, Ag ₂ SO
₄ , Ag ₂ S) may be added to change the sharpness and color tone of the coloring, so that a wider variety of color tones can be exhibited. In this coloring method, it is needless to say that the inorganic filler may be added to the colorant composition, but when it is added to the photosensitive resin composition, the patterning shape is slightly deteriorated when the formation area is relatively large. The omission and shrinkage of the shape are improved.

In the present invention, a colorant composition obtained by dispersing or dissolving one kind or a plurality of kinds of the above colorants in a solvent is used. In this case, in order to further increase the dispersion stability, a small amount of resin used in the photosensitive resin composition may be added, or any conventionally known additive such as a surfactant may be included as necessary. is there. As a method for dispersing these, for example, a ball mill, a sand mill, a roll mill, a speed line mill and the like can all be used, and the ball mill is particularly useful in the present invention.

Any photosensitive polymer may be used in the photosensitive resin composition used in the present invention as long as it does not affect the color development and can be burned out during firing, leaving almost no residue. May be used, and any photo-crosslinking agent may be used. In particular, the facility is simple, economical,
In consideration of work safety, a water-soluble (water-developable) photosensitive resin composition is easy to handle.

Examples of the photosensitive polymer include homopolymers of polyacrylamide, polyvinylpyrrolidone, polyvinyl methyl ether, polyvinyl acetal, gelatin, casein, glue, polyethylene oxide, etc., or copolymers of acrylamide-diacetamide, and maleic acid-methyl. Vinyl ether copolymers, acrylamide-vinyl alcohol copolymers, polyisoprene, polyvinyl cinnamate, polyvinyl alcohol, natural rubber and the like are preferably used. On the other hand, as the photocrosslinking agent, an organic curing agent such as a diazo compound or an azide compound is preferable, but it goes without saying that a commercially available resist may be used.

The photosensitive resin composition used in the present invention contains the above-mentioned components as essential components, but may include any other conventionally known additives as required. Also,
The amount of the solvent used varies depending on the type of the photosensitive polymer used, the concentration of the colorant, and the coating method, but a range of 50 to 98 wt% is generally good.

As a method for applying the above-mentioned photosensitive resin composition onto a desired glass substrate, any of known coating methods such as doctor blade coating, near bar coating, roll coating, screen coating, screen printing and spinner coating can be used. Although it can be used, doctor blade coating is most suitable in terms of preventing inclusion of bubbles, prevention of sedimentation of colorant, inclusion of bubbles, and uniformity of coating amount.

The thickness of the coating film formed as described above varies depending on the material, but it is generally preferably about 0.5 to 30 μm when dried. The steps and conditions such as drying of the coating film, curing by patterning exposure, development by elution of unexposed portions, and baking are not particularly limited as described above and as illustrated in specific examples described below. The same as in.

[Specific Example] A colorant composition for each color was prepared as follows.

"Colorant composition for red filter" Copper sulfate (7.4 wt%), sodium sulfate (14.7 w)
t%), alumina (7.4 wt%), polyvinyl alcohol (0.3 wt%), and pure water (70.2 wt%) are mixed and dispersed by a ball mill.

"Colorant composition for green filter" Copper sulfate (0.9 wt%), cobalt oxide (0.9 wt)
%), Chromium oxide (0.6 wt%), glass frit (27.1 wt%), polyvinyl alcohol (0.3
wt%) and pure water (70.2 wt%) are mixed and dispersed by a ball mill.

"Colorant composition for blue filter" Cobalt type pigment (4.4 wt%), glass frit (2
5.1 wt%), polyvinyl alcohol (0.3 wt
%) And pure water (70.2 wt%) are mixed and dispersed by a ball mill.

"Colorant composition for black matrix" Cobalt-chromium-iron heat resistant black pigment 4.4 wt%, glass frit 25.1 wt%, polyvinyl alcohol (0.3 wt%), pure water (70.2 wt%) ) Are mixed and dispersed by a ball mill.

A 4.5 wt% aqueous solution of polyvinyl alcohol (Kuraray 224) was prepared as a photosensitive resin composition. At this time, 1.02 wt% of the total amount of p-diazophenylamine formaldehyde condensate (D-014 manufactured by Shinko Giken Co., Ltd.) is mixed and used.

Then, pattern formation was performed by the following procedure.

First, the above-mentioned photosensitive resin composition 2 was applied onto a glass substrate 1 by a blade coater and dried at room temperature, and then ultraviolet rays having a maximum wavelength of around 350 nm were passed through a mask M at 62 mJ / cm 2. ^{2 The} patterning portion 2a was formed by exposure. Then, spray development with warm water (35 ° C.) is performed to remove the unexposed portion 2b.
It was dried at 0 ° C. Next, after immersing in the colorant composition for the black matrix and rinsing with water after 10 minutes, the patterned portion 2a was dried and hardened at 160 ° C. to form the colored portion 3.

Subsequently, with respect to the colorant composition for green filters, the colorant composition for blue filters, and the colorant composition for red filters, after repeating the steps from coating to film hardening in the same manner, about 580 The resin content (polyvinyl alcohol) and the curing agent (formaldehyde condensate of p-diazodiphenylamine) in the slurry are burned off by baking at 30 ° C for 30 minutes, and at the same time, the coloring reaction is promoted and the red color is formed on the substrate. A color filter was formed separately for each color, green and blue.

Electrodes and the like were formed on the color filter thus formed to form a DC type color PDP and an AC type color PDP as shown in FIGS. 4 and 5. As a result, a PDP with high contrast could be obtained. 4 and 5, parts other than the filter are denoted by the same reference numerals as those in FIGS. 1 and 2.

[0048]

As is apparent from the above description, according to the present invention, a colorant composition having a heat-resistant colorant dispersed or dissolved therein is used as a photosensitive resin composition formed by a photolithography method. The patterning part was impregnated, and the organic component was burned out through baking, and the coloring reaction was promoted so that the coloring agent was brought into close contact with the substrate, so it had excellent heat resistance, no gas emission, film thickness uniformity, and resolution. It is possible to form a color filter for a substrate for a plasma display, which is satisfactory in terms of properties and processing accuracy.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of a conventional DC type plasma display panel.

FIG. 2 is a cross-sectional view showing a configuration example of a conventional AC type plasma display panel.

FIG. 3 is a process drawing of a method for forming a color filter for a plasma display substrate according to the present invention.

FIG. 4 is a process drawing that follows FIG.

FIG. 5 is a cross-sectional view of a DC type plasma display panel using a substrate having a color filter as a front plate.

FIG. 6 is a cross-sectional view of an AC type plasma display panel using a substrate having a color filter as a front plate.

[Explanation of symbols]

 1 Substrate 2 Photosensitive Resin Composition 2a Patterning Part 2b Non-Pattern Forming Part 3 Coloring Part 4 (Black) Coloring Part 5 Filter Part 6 Black Matrix M Mask

Claims (8)

[Claims] 1. A coating step of coating and drying a photosensitive resin composition on a glass substrate on which a color filter is to be formed, and an exposure step of forming a patterning portion by exposure through a mask of a color filter pattern. A development step of removing the non-patterned portion by development, an impregnation step of impregnating the patterned portion with a colorant composition in which a heat-resistant colorant is dispersed or dissolved, and an organic component that is burned to burn off the organic matter on the substrate. A method for forming a color filter of a substrate for a plasma display, which comprises a firing step of forming a filter portion. 2. The method for forming a color filter for a plasma display substrate according to claim 1, wherein each of the colorant compositions contains a plurality of colorants having different transmission wavelengths. Process,
A method for forming a color filter for a plasma display substrate, comprising forming a filter portion in which each color is selectively arranged on the substrate by performing a firing process after repeating the impregnation process. 3. The method for forming a color filter for a plasma display substrate according to claim 1, wherein a black matrix is formed by adding the same steps to a colorant composition containing a heat-resistant black colorant. A method for forming a color filter for a plasma display substrate, the method comprising: 4. The coating process is performed by doctor blade coating.
A method for forming a color filter for a substrate for a plasma display as described above. 5. The method for forming a color filter for a plasma display substrate according to claim 1, wherein the exposing step is performed from the surface opposite to the coated surface of the glass substrate. 6. The method of forming a color filter for a plasma display substrate according to claim 1, wherein a heat resistant pigment is used as the colorant. 7. The method of forming a color filter for a plasma display substrate according to claim 1, 2, 3, 4, or 5, wherein colored glass is used as the coloring agent. 8. The substrate for plasma display according to claim 1, wherein a material for exchanging alkali ions in the substrate glass with colored ions is used as the coloring agent. Color filter forming method.