JP3177300B2 - Method for forming color filter on substrate for plasma display - Google Patents

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 on a substrate for a plasma display constituting a plasma display panel (hereinafter abbreviated as PDP).

[0002]

2. Description of the Related Art FIG. 1 shows a conventional DC having a reflective phosphor screen.
This is an example of a configuration of a mold PDP, in which a flat front plate 11 and a rear plate 12 made of glass are arranged in parallel and opposed to each other, and both are fixed at a predetermined distance by a cell barrier 13 provided therebetween. Is held in. A plurality of linear anodes 14 parallel to each other are formed on the back surface of the front plate 11, and a plurality of linear cathodes 15 parallel to each other are formed on the front side of the back plate 12. It is formed. Further, a fluorescent layer 16 is formed adjacent to the inner surface of the cell barrier 13, and the fluorescent layer 16 emits red (R), green (G), and blue (B) fluorescent light for each cell 17. The body is provided in a predetermined pattern.

In the above-described conventional DC-type PDP, a front panel 11 and a rear panel 12 are formed by applying a predetermined voltage from a DC power source between an anode 14 and a cathode 15 to form an electric field.
Each cell 1 as a display element composed of a cell and a cell barrier 13
Discharge takes place inside 7. The ultraviolet light generated by the discharge causes the fluorescent layer 16 to emit light, and the light transmitted through the front plate 11 is visually recognized by the observer.

FIG. 2 shows an example of the configuration of a conventional AC PDP having a reflective phosphor screen.
Similarly to the DC type PDP, a flat front plate 21 and a rear plate 22 made of glass are arranged in parallel and opposite to each other in P, and both are fixed by a cell barrier 23 provided therebetween. It is kept at intervals. An electrode 24 for writing is formed under the cell barrier, and electrodes 26 and 27 are formed in parallel on the rear side of the front plate 21 so as to correspond to the cells 25 in pairs, and on the rear 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 side of the back plate 22.

In the above-mentioned conventional AC type PDP, an electric field is formed by applying a predetermined voltage from an AC power source between a pair of electrodes 26 and 27 formed on the front plate 21.
Discharge is performed in each cell 25 as a display element between the front plate 21, the back plate 22, and the cell barrier 23. The ultraviolet light generated by the discharge causes the fluorescent layer 30 to emit light, and the light transmitted through the front plate 21 is visually recognized by the observer.

[0006]

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

To make the display easier to see, it is effective to reduce the reflectance and improve the contrast.
As a means for achieving this, the front panel is provided with ND (Neutral Density) filter characteristics. Nd ₂ O ₃ is put in the front plate to give absorption characteristics outside the main spectrum of the luminous body. Fill the area other than the fluorescent layer with a low reflection material. That is,
A black matrix is formed. The pigment is mixed with 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 of the red, green, and blue cells. However, unlike a CRT, a PDP does not have much room for luminance. Therefore, a color filter with a black matrix is effective for minimizing luminance decrease and increasing contrast. Then, in the color PDP, it is necessary to provide them inside the front plate in view of the viewing angle. However, for this purpose, it is required that the substrate be able to withstand a high temperature of about 450 to 600 ° C. or higher and that no gas is emitted in the process of forming the substrate. In this regard, the currently used color filters for liquid crystal display elements cannot be used as they are.

On the other hand, a method of forming a color filter by screen printing by converting a material into a paste is known. However, the film thickness uniformity, the resolution, and the processing accuracy are not always satisfactory especially when considering a large size. It doesn't work.

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

[0010]

In order to achieve the above-mentioned object, a method of forming a color filter for a plasma display substrate according to the present invention comprises a heat-resistant coloring agent on a glass substrate on which a color filter is to be formed. A coating step of applying the photosensitive resin composition thus obtained, an exposure step of forming a patterned portion by exposure through a color filter pattern mask, a development step of removing an unexposed portion by development, and a photosensitive resin composition. And a firing step of forming a filter portion by burning off the organic components of the organic solvent.

In the case where a plurality of filters having different transmission wavelengths are formed on the same plane, the above-mentioned coating step may be applied to each photosensitive resin composition containing a plurality of colorants having different transmission wavelengths. The baking step is performed after the exposure step and the developing step are repeatedly performed, so that a filter portion in which each color is selectively arranged may be formed on the substrate.

Further, when a black matrix is formed, a similar step may be added to a photosensitive resin composition to which a heat-resistant black pigment has been added.

It is preferable that the application step is performed by doctor blade coating, and that the exposure step is performed from the surface opposite to the application surface of the glass substrate.

As the coloring agent used in the above-mentioned forming method, a heat-resistant pigment or colored glass can be used, and further, a material which exchanges alkali ions in the substrate glass with colored ions can be used. it can.

[0015]

According to the method for forming a color filter of a substrate for a plasma display of the present invention, a color filter having a uniform film thickness and excellent in resolution and processing accuracy is formed by a photolithography method. In addition, organic components are burned off in the firing step, and a color filter without gas emission is formed.

[0016]

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

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

First, as shown in FIG. 3A, a flat substrate 1 made of glass is washed to determine a filter forming surface. Here, when using a glass substrate or the like formed by a float method, it is necessary to select whether the glass surface is a tin surface or a non-tin surface according to the coloring agent used. In other words, when a tin surface is used, tin ions may enter the glass depending on the type of the coloring agent used and exert an adverse effect, and a material that exchanges alkali ions in the substrate glass with the coloring ions as a coloring agent. In the case of using tin, there are many cases where the tin surface is more easily ion-exchanged and the coloration is improved.

Next, in the step (b), the photosensitive resin composition 2 containing a colorant is applied to the entire surface of the substrate 1 on which the color filter is to be formed and dried. As a coating method, any coating method such as a spray method, a spinner method, a dip method, a printing method, a blade coater method, and a roll coater method can be adopted.

Subsequently, in a step shown in FIG. 3C, patterning is performed by pattern exposure through a color filter pattern mask M to form a patterning portion 2a. 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 uniformity of the film thickness.

Next, in the step (d), after the unexposed portion 2b is removed by development, the patterning portion 2b is removed.
a is dried and hardened.

In the case of three color PDPs, a photosensitive resin composition containing a colorant having a transmission wavelength of red, green, and blue, respectively, is applied to the photosensitive resin composition (b), the exposure step (c), and the exposure step (c). The developing step d) is repeated. further,
When a black matrix is provided, the same steps are performed for a photosensitive resin composition to which a heat-resistant black pigment has been added.

Finally, the substrate is moved to a firing step, where the substrate is fired at a temperature sufficient for a coloring reaction to burn off remaining organic components. Through the above steps, 3 containing the black matrix
In the case of a color filter of colors (R, G, B), a filter portion 3 having a pattern as shown in FIG.
And a black matrix 4 are formed.

By using a photosensitive resin composition containing a colorant as described above, a color filter having high uniformity, excellent resolution and dimensional accuracy can be formed. Further, by passing through the firing step, it is possible to burn out the organic components that cause outgassing. At this time, depending on the colorant, it can be expected that the adhesion will be increased and the coloring reaction will be accelerated.

As the colorant dispersed in the photosensitive resin composition, any heat-resistant pigment can be used. In this case, although it depends on the manufacturing process of the substrate, 450 to
What is necessary is just to have the heat resistance of about 600 degreeC. In addition, a color glass that can ensure wavelength selectivity with a thin film thickness, a material that exchanges alkali ions in a substrate glass with colored ions, and the like can be used. In addition, color development and its stability, heat resistance,
It is also effective to mix a glass frit having a low melting point to improve adhesion and surface smoothness.

Although there are many types of heat-resistant pigments, typical ones are iron (red), manganese aluminate (pink), gold (pink), antimony-titanium-chromium (orange), iron -Chromium-zinc (brown), iron (brown), titanium-chromium (yellow-brown), iron-chromium-zinc (yellow-brown), iron-antimony (yellow-brown), antimony-titanium-chromium (Yellow), zinc-vanadium (yellow), zirconium-vanadium (yellow), chromium (green), vanadium-chromium (green), cobalt (blue), cobalt aluminate (blue), vanadium- Zirconium (blue), cobalt-chromium-
There are iron-based (black) and the like, and the color tone can be adjusted by mixing these. It is desirable that particles having a particle size of 1 μm or more account for 10% by weight or less of all particles. That is, if there are many particles having a large particle diameter, the transmittance is reduced and the luminance is reduced.

There are many types of colored glass due to the coloring mechanism. Also, the color of the same raw material changes depending on the conditions. As an example, the 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. The raw materials are silica stone, lead red, yellow lead oxide, lead white, potassium nitrite, boric acid, borax ,
Sodium bicarbonate, fluoride and the like are used. As coloring agents, arsenous acid (white), tin oxide (white), copper oxide (green), cobalt oxide (blue), potassium dichromate (yellow), antimony oxide (yellow), iron oxide (brown), manganese dioxide (Purple), nickel oxide (purple), gold chloride (red), sodium uranate (orange), selenium red (red) and the like are combined and mixed. Then, a mixture obtained by mixing, heating and melting, vitrifying and cooling and pulverized is used.

As a typical material for exchanging alkali ions in the substrate glass with colored ions, red (copper sulfate 5 to 40 parts by weight, alkali metal salt 40 to 90 parts by weight, inorganic filler 5 to 5 parts by weight) 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)
To 20 parts by weight).

Here, the alkali metal salts are lithium sulfate, sodium sulfate, and potassium sulfate as alkali metal sulfates, and one or two kinds of alkaline earth metal sulfates are zinc sulfate, calcium sulfate, magnesium sulfate, and barium sulfate. The above mixture is used. These are considered to have the function of melting mainly on the glass surface to improve the adhesion to the glass substrate surface and promote ion exchange.

The inorganic filler is considered to have a function of preventing shrinkage of the melt at the time of firing and a function of controlling the density of a color tone, and various kinds of 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. 1 if necessary
Parts by weight or less of silver salt (AgNO ₃ , Ag ₂ O, Ag ₂ SO
By adding ₄ , Ag ₂ S), the clarity of coloring and the color tone may be changed in some cases, and a wider variety of color tones can be exhibited.

Further, the photosensitive resin composition used in the present invention satisfies conditions such as being unaffected by the substance to be dispersed, having no effect on color development, being burnt off during firing and leaving little residue. Any photosensitive polymer may be used, and any photocrosslinking agent may be used. In particular, a water-soluble (water-developable) photosensitive resin composition is easy to handle in view of simplicity of equipment, economy, and operational safety.

Examples of the photosensitive polymer include homopolymers such as polyacrylamide, polyvinylpyrrolidone, polyvinyl methyl ether, polyvinyl acetal, gelatin, casein, glue, polyethylene oxide, acrylamide-diacetamide copolymer, and maleic acid-methyl ester. Vinyl ether copolymer, acrylamide-vinyl alcohol copolymer, polyisoprene, polyvinyl cinnamate, polyvinyl alcohol, natural rubber and the like are preferably used. On the other hand, as the photo-crosslinking 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 necessary. Also,
The amount of the solvent to be used varies depending on the type of the photosensitive polymer to be used, the concentration of the colorant, and the method of application, but is generally preferably in the range of 20 to 80% by weight. Further, as a method of dispersing the colorant in the photosensitive resin composition, for example, any of a ball mill, a sand mill, a roll mill, a speed line mill and the like can be used, and a ball mill is particularly useful in the present invention.

As a method for applying the photosensitive resin composition containing the colorant on a glass substrate, known coating methods such as doctor blade coating, miller bar coating, roll coating, screen coating, screen printing, spinner coating and the like can be used. Any of these can be used, but doctor blade coating is most suitable from the viewpoint of prevention of entrapment of air bubbles, sedimentation of a coloring agent, mixing of air bubbles, and uniformity of application amount.

The thickness of the coating film formed as described above varies depending on the material, but is generally preferably about 5 to 50 μm when dried. Drying of coating film,
Curing by patterning exposure, development by elution of unexposed portions, and further, each step such as baking and the conditions thereof are not particularly limited as described above and exemplified in the specific examples described later, and are the same as those in the prior art. Is fine.

[Specific Example] First, a photosensitive resin composition (slurry) containing a colorant was prepared as follows.

As a slurry for the red filter, 7.4% by weight of copper sulfate, 14.7% by weight of sodium sulfate, 7.4% by weight of alumina, 1.7% by weight of gelatin, 14.7% by weight of methanol, and 54.1% by weight of pure water were mixed. Dispersed in a ball mill, 1.02wt% of the total amount when used
Was mixed with a formaldehyde condensate of p-diazodiphenylamine (D-014, manufactured by Shinko Giken Co., Ltd.).

The slurry for the green filter includes copper sulfate 0.9 wt%, cobalt oxide 0.9 wt%, chromium oxide 0.6 wt%, glass frit 27.1 wt%, gelatin 1.7 wt%, methanol 14.7 wt%, Pure water 5
The mixture obtained by mixing 4.1 wt% is dispersed in a ball mill,
At the time of use, 1.02 wt% of a total amount of a formaldehyde condensate of p-diazodiphenylamine (D-014 manufactured by Shinko Giken Co., Ltd.) was mixed.

As the slurry for the blue filter, 4.4 wt% of a cobalt pigment and 25.1 wt of a glass frit were used.
%, Gelatin 1.7wt%, methanol 14.7wt
% And pure water 54.1 wt% were dispersed in a ball mill, and 1.02 wt% of a total amount of formaldehyde condensate of p-diazodiphenylamine (D-014 manufactured by Shinko Giken Co., Ltd.) was mixed at the time of use.

As the slurry for the black matrix,
Cobalt-chromium-iron heat-resistant black pigment 4.4 wt%, glass frit 25.1 wt%, gelatin 1.7 wt%,
A mixture of 14.7% by weight of methanol and 54.1% by weight of pure water was dispersed in a ball mill, and when used, the total amount of the mixture was 1.
A formaldehyde condensate of p-diazodiphenylamine (D-014, manufactured by Shinko Giken Co., Ltd.) was mixed at 02 wt%.

Next, a slurry for a black matrix was coated on the glass substrate 1 by doctor blade coating.
After coating at 0 ° C. and drying at room temperature, an ultraviolet ray having a maximum wavelength around 350 nm is irradiated with 62 mJ / c through a mask M.
Exposure to m ² formed a patterning portion 2a. Next, the unexposed portion 2b was removed by spray development with water. Subsequently, after drying and hardening of the patterning portion 2a at 160 ° C., the resin component (gelatin) in the slurry and the curing agent (formaldehyde condensation of p-diazodiphenylamine) are baked at about 580 ° C. for 30 minutes. ) Was burned off.

Subsequently, a slurry for a green filter,
For the blue filter slurry and the red filter slurry, coating, drying, exposure and development are repeated in the same manner,
By baking at about 580 ° C. for 30 minutes, organic components such as a resin component (gelatin) and a curing agent (formaldehyde condensate of p-diazophenylamine) in the slurry are burned off, and the substrate is separately coated in red, green and blue. The resulting color filter was formed.

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

[0044]

As is apparent from the above description, according to the present invention, a predetermined pattern is formed by a photolithography method using a photosensitive resin composition containing a heat-resistant colorant, and then fired. The organic component is burned off through the process, so it is possible to form a color filter for a plasma display substrate that is excellent in heat resistance, has no outgassing, and is satisfactory in film thickness uniformity, resolution, and processing accuracy. .

[Brief description of the drawings]

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

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

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

FIG. 4 is a cross-sectional view of a DC plasma display panel using a substrate on which a color filter is formed as a front plate.

FIG. 5 is a cross-sectional view of an AC plasma display panel using a substrate on which a color filter is formed as a front plate.

[Explanation of symbols]

 Reference Signs List 1 glass substrate 2 photosensitive resin composition containing colorant 2a patterned portion 2b unexposed portion 3 filter portion 4 black matrix M mask

Continuation of the front page (56) References JP-A-61-279803 (JP, A) JP-A-60-129707 (JP, A) JP-A-4-249032 (JP, A) JP-A-1-145603 (JP) JP-A-62-150202 (JP, A) JP-A-58-224310 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 9/24 G02B 5/20 H01J 17/49

Claims (9)

(57) [Claims] 1. A coating step of applying a photosensitive resin composition containing a heat-resistant colorant onto a glass substrate on which a color filter is to be formed, and a patterning portion formed by exposure through a color filter pattern mask. A plasma display comprising: an exposing step of forming, a developing step of removing an unexposed part by development, and a baking step of forming a filter part by burning off an organic component of the photosensitive resin composition by baking. A method of forming a color filter on a substrate. 2. The method for forming a color filter of a substrate for a plasma display according to claim 1, wherein the coating step, the exposing step, and the photosensitive resin composition each containing a plurality of coloring agents having different transmission wavelengths. By performing the firing step after repeatedly performing the development step,
A method of forming a color filter for a substrate for a plasma display, comprising: forming a filter portion in which each color is arranged selectively on a substrate. 3. The method for forming a color filter of a substrate for a plasma display according to claim 1, wherein a black matrix is formed by adding a similar step to the photosensitive resin composition to which a heat-resistant black pigment is added. A method for forming a color filter on a substrate for a plasma display, comprising: 4. A color filter forming method of the plasma display substrate according to claim 1, 2 or 3, wherein the performing the coating cloth step by doctor blade coating. Claim 1, 2, 3 or 4 wherein EXPOSURE step and performing a surface opposite to the coated surface of the glass substrate
A method for forming a color filter on a substrate for a plasma display according to the above. 6. The color filter forming method of the plasma display substrate according to claim 1, 2, 3, 4 or 5, wherein the use of heat-resistant pigment as wearing colorant. 7. The color filter forming method of the plasma display substrate according to claim 1, 2, 3, 4 or 5, wherein the use of colored glass as wearing colorant. 8. wearing colorant as a plasma display substrate according to claim 1, 2, 3, 4 or 5, wherein the use of materials such as the alkali ions of the substrate in the glass exchanges with coloring ions Color filter forming method. 9. The front panel has three color filters.
A plasma display panel,
Filters are photosensitive resins that contain heat-resistant pigments as colorants.
Predetermined pattern by photolithography method using fat composition
And burn off organic components through firing.
The heat resistance in the color filter
For pigments, particles with a particle size of 1 μm or more are 10 wt% or less of all particles.
A plasma display panel, characterized in that: