JP3000970B2 - Method for manufacturing plasma display panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel used for a display device or the like, in particular, a black mask having a low reflectance which is partially formed to enhance the contrast of a display, with high accuracy and a simple process. And a method for manufacturing a plasma display panel.

[0002]

2. Description of the Related Art The structure of a plasma display panel will be described with reference to FIG. As shown in the drawing, the plasma display panel includes a first substrate 1a, a strip-shaped transparent electrode pair including an electrode 2a and an electrode 2b, a black mask 3 between adjacent transparent electrodes 2a, 2b, and a transparent electrode 2a, 2b. 2
b and a transparent dielectric layer 4 that covers the black mask 3 so as to be electrically insulated, and a protective layer made of a magnesium oxide (MgO) thin film (not shown) is formed on the transparent dielectric layer 4. Used as a front substrate.

Further, the transparent electrode 2 is provided on a second substrate 1b.
a, a strip-shaped metal electrode 5 extending in a direction perpendicular to a and 2b;
Dielectric layer 6 covering metal electrode 5 so as to be electrically insulated
A partition wall 7 for separating each light emitting cell and forming a discharge space, and a side surface of the partition wall 7 for obtaining a desired emission color.
A phosphor layer 8 is formed on the bottom surface and is used as a back substrate.

The above-mentioned front substrate and rear substrate are overlapped at a predetermined position and sealed with frit glass (not shown).
After heating and exhausting the inside, the discharge gas is sealed inside,
Completed as a plasma display panel. The plasma display panel generates an electric discharge by applying an AC pulse between each of the transparent electrodes 2a and 2b, and excites the phosphor with ultraviolet rays generated by the electric discharge to obtain visible light emission. At this time, light emission can be selected by the metal electrode 5.

As a method of forming the transparent electrodes 2a and 2b, a transparent conductive film made of, for example, indium tin oxide (ITO) is formed on the entire surface of the substrate, and a desired resist pattern is formed by a photolithography method. An etching method of removing unnecessary portions of the transparent conductive film with an etching solution comprising a mixed solution of 2 iron and nitric acid and an etching method of removing a resist, or forming a desired resist pattern on a substrate by photolithography, For example, a lift-off method is used in which a transparent conductive film is formed on the substrate, and unnecessary portions of the transparent conductive film are removed together with the resist.

On the other hand, since the body color of the phosphor layer 8 is white or light gray, when the external light hits the panel, the display dots that are emitting light and the non-display dots that are not emitting light are not bright or dark. There is a problem that the display becomes clear and the contrast of the display deteriorates. One method of increasing the display contrast is to lower the surface reflectance of the panel. The black mask 3 reduces the reflectance by making the gap between the transparent electrodes 2a and 2b that contribute relatively little to light emission black, thereby lowering the overall reflectance of the panel surface more than the reduction rate of luminance. This has the effect of substantially improving the display contrast. Also,
As a method for forming a black mask, direct application by screen printing or a photolithography method using a photosensitive material is used.

[0007]

As apparent from FIG. 3, the black mask 3 is provided with the transparent electrodes 2a and 2a.
It needs to be arranged between b. However, when the coating method by screen printing is used, it is difficult to form with high positional accuracy due to expansion and contraction of a screen plate used for printing. Further, according to the photolithography method using a photosensitive black mask material, it is possible to form the black mask 3 with high precision, but the transparent electrodes 2a and 2b can be formed.
There is a problem that the process using photolithography is performed twice, including the forming process, and the process becomes longer.

An object of the present invention is to provide a method of manufacturing a plasma display panel in which a black mask for improving contrast is formed with high accuracy by simple steps.

[0009]

In order to achieve the above object, a method of manufacturing a plasma display panel according to the present invention is directed to a method of manufacturing a plasma display panel obtained by securing a gap between a pair of insulating substrates and bonding them. In the method, one of the pair of insulating substrates has a visible light transmitting property, and divides a display picture element parallel to the transparent electrode and at least one pair of transparent electrodes having a visible light transmitting property. A black mask formed as described above, which includes a dielectric layer that electrically insulates the transparent electrode and the black mask having visible light transmittance, and a step of forming the transparent electrode and the black mask, A step of applying a photosensitive black mask material in a strip shape so as not to cover a discharge gap formed in the center of each transparent electrode, including a black mask forming portion, and Forming a photoresist layer on the substrate, exposing the photosensitive black mask material and the photoresist simultaneously using a transparent electrode-shaped mask, developing the photosensitive black mask material and the photoresist, Forming a transparent conductive film on the entire surface; removing the photoresist; and baking the photosensitive black mask material to form a black mask.

Further, the photosensitive black mask material and the photoresist are of a negative type in which the exposed portions remain after development.

In addition, the photosensitive black mask material and the photoresist are of a positive type in which portions that are not exposed to light remain after development.

The method for applying the photosensitive black mask material is based on a screen printing method.

The method of applying the photosensitive black mask material is based on a dispenser method.

Further, the photoresist is simultaneously carbonized and removed when the photosensitive black mask material is baked.

By forming a pattern of the black mask and the transparent electrode by one exposure using the same mask, the positional relationship between the transparent electrode and the black mask does not deviate.
In addition, the steps are simplified. In addition, since the photosensitive black mask material is partially formed, it is not formed in the discharge gap portion where light emission is strong, and the light emission luminance does not significantly decrease. The photosensitive black mask material may be formed so as to completely include the portion where the black mask is to be formed and not to cover the discharge gap portion, and can be formed by screen printing with low positional accuracy or application by a dispenser. is there. In addition, if the photosensitive black mask material and the photoresist are both negative type or hoji type, the same pattern can be obtained.

In the technique disclosed in Japanese Patent Application Laid-Open No. Hei 7-262923, a resist is formed in a part of a cell, a phosphor layer is formed in a cell containing the resist, and then the resist is removed. Japanese Patent Application Laid-Open No. Hei 7-262923 describes that a pattern is formed only on a phosphor layer.
On the other hand, in the present invention, two kinds of substances, that is, a transparent electrode and a black mask, are patterned at once, which is a completely different method.

[0017]

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

(Embodiment 1) FIG. 1 is a sectional view showing a main part of a method for forming a pattern of a transparent electrode and a black mask according to a first embodiment of the present invention in accordance with steps.

In the figure, 1a is an insulating substrate having a visible light transmission property, 9a is a negative photosensitive black mask material, 10a is a negative photoresist (in the first embodiment, a dry film resist described later), 2c is a transparent conductive film, and 11 is a glass mask for exposure. Hereinafter, description will be made in accordance with the steps.

First, as shown in FIG.
Photosensitive black mask material 9 by screen printing on top
a is formed at a position corresponding to between the adjacent transparent electrodes 2a and 2b (see FIG. 3) in a band shape perpendicular to the drawing paper surface. At this time, the photosensitive black mask material 9a does not need to be precisely formed in both width and position, but includes a portion for forming the black mask 3 and a discharge gap portion formed in the center of each of the transparent electrodes 2a and 2b. It is good if it does not depend on. As the photosensitive black mask material 9a, a low melting glass powder is mixed with a metal oxide powder containing chromium oxide (Cr2O3) and cobalt oxide (Co2O3) as main components,
Further, a paste obtained by mixing with a negative photosensitive resin and a solvent is used. Next, a negative type dry film resist (hereinafter, referred to as DFR) 10a is adhered to the entire surface of the substrate including the photosensitive black mask material 9a by a hot roll laminating method.

Subsequently, as shown in FIG. 1B, a DFR 10a and a photosensitive black mask material 9a are formed by using an exposure mask (glass mask) 11 having an opening at a portion where the transparent electrodes 2a and 2b are not formed. Are simultaneously exposed. The exposed substrate 1a is developed with a dilute sodium carbonate solution,
By removing the non-exposed portion, the DFR 10a is provided in a portion corresponding to the discharge gap, and the photosensitive black mask material 9a and the D
The FR 10a remains (FIG. 1c).

Further, as shown in FIG. 1D, tin oxide-antimony (SnO
2: A transparent conductive film 2c made of Sb2O3) is formed. Finally, the substrate 1a on which the transparent conductive film 2c is formed is fired in an air furnace at 600 ° C. Thus, the DFR 10a can be carbonized and the transparent conductive film 2c on the DFR 10a can be removed at the same time. Further, a photosensitive black mask material 9
The black mask 3 is obtained by baking a at the same time (FIG. 1e).

Further, in order to form a plasma display panel, a transparent dielectric layer and a protective layer are formed as described in the prior art, and a gap is secured between the transparent dielectric layer and a separately manufactured rear substrate. A discharge gas is sealed in the gap to complete a plasma display panel.

(Embodiment 2) Next, Embodiment 2 of the present invention
Will be described with reference to FIG. FIG. 2 is a cross-sectional view of a main part showing a method of forming a pattern of a transparent electrode and a black mask according to a second embodiment of the present invention in accordance with steps.

In FIG. 2, 1a is an insulating substrate having a visible light transmission property, 9b is a positive photosensitive black mask material, 10b is a positive photoresist, 2c is a transparent conductive film, and 11 is a light-transmitting conductive film. It is a glass mask. Hereinafter, description will be made in accordance with the steps.

First, as shown in FIG. 2A, a photosensitive black mask material 9b is placed on a substrate 1a by a dispenser at a position corresponding to a position between adjacent transparent electrodes 2a and 2b (see FIG. 3). Form a vertical strip. At this time, the photosensitive black mask material 9b does not need to be formed accurately in both width and position, but includes a portion where the black mask 3 is formed and a discharge gap portion formed in the center of each of the transparent electrodes 2a and 2b. It is good if it does not depend on. As the photosensitive black mask material 9b, a metal oxide powder containing chromium oxide (Cr2O3) and cobalt oxide (Co2O3) as main components is mixed with a low melting glass powder,
Further, a paste obtained by mixing with a positive photosensitive resin and a solvent is used.

Next, as shown in FIG. 2B, a positive type photoresist 10b is applied by a roll coater on the entire surface of the substrate including the photosensitive black mask material 9b. Subsequently, the photoresist 10b and the photosensitive black mask material 9b are simultaneously exposed using an exposure mask (glass mask) 11 in which portions where the transparent electrodes 2a and 2b are to be formed have openings. The exposed substrate 1a is developed with a dilute solution of sodium hydroxide, and the exposed portion is removed.
b, the photosensitive black mask material 9b and the photoresist 10b remain between the adjacent transparent electrodes 2a, 2b (FIG. 2c).

Further, as shown in FIG. 2D, a transparent conductive film 2c made of indium-tin oxide (ITO) is formed on the entire surface of the substrate by vapor deposition.

Further, as shown in FIG. 2E, the photoresist 10b is dissolved and removed in a solvent, and at the same time, the transparent conductive film 2c on the photoresist 10b is removed. Finally, the substrate 1a is fired in an air furnace at 600 ° C., and the photosensitive black mask material 9b is fired to obtain the black mask 3.

Although the positive and negative photoresists have been described in the embodiments, these photoresists are liquids having high sensitivity and low viscosity and are very easy to handle. Is done. However, since an alkaline solution is mainly used as a developing solution, an effect such as dissolution of glass contained in a photosensitive black mask material may be exerted depending on conditions. In such a case, the problem can be avoided by using a negative photoresist. In practice, it is possible to select whether a positive type or a negative type photosensitive material is to be used in consideration of the amount of glass eluted during development.

[0031]

As described above, according to the present invention, the process for manufacturing a plasma display panel without a black mask is different from the process for applying a photosensitive black mask material by screen printing in the first embodiment and the second embodiment in the second embodiment. A black mask with high positional accuracy can be formed only by increasing the application step of the photosensitive black mask material by the dispenser. This is more accurate than forming a black mask by screen printing only,
In addition, the process is simpler than when only the black mask is formed alone by the photolithography method.

Further, according to the present invention, a black mask is formed on the entire gap between adjacent transparent electrode pairs which is not a discharge gap. However, in a surface discharge type plasma display panel in which a discharge mainly contributing to light emission is formed by two discharge electrodes running in parallel on the same substrate, most of light emission is from a discharge gap or a discharge electrode portion. . The light emission from the gap between the discharge electrode pairs is weak, and the formation of the black stripe has little effect on the luminance reduction. According to the present invention, the effect of improving the contrast by reducing the panel surface reflectance can be effectively obtained. .

[Brief description of the drawings]

FIG. 1 is a fragmentary cross-sectional view showing a method of forming a pattern of a transparent electrode and a black mask according to a first embodiment of the present invention in accordance with steps.

FIG. 2 is a fragmentary cross-sectional view showing a method of forming a pattern of a transparent electrode and a black mask according to a second embodiment of the present invention in accordance with steps;

FIG. 3 is a diagram schematically showing a structure of a plasma display panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1a Substrate 2a, 2b Transparent electrode 3 Black mask 4 Transparent dielectric layer 5 Metal electrode 6 Dielectric layer 7 Partition wall 8 Phosphor layer 9a, 9b Photosensitive black mask material 10 Photoresist 11 Glass mask for exposure

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01J 9/02 H01J 9/227 H01J 11/00-11/04 H01J 17/00-17/49

Claims (6)

(57) [Claims] 1. A method of manufacturing a plasma display panel comprising a pair of insulating substrates bonded to each other while securing a gap between the pair of insulating substrates, wherein one of the pair of insulating substrates has a visible light transmitting property and a visible light transmitting property. A pair of transparent electrodes having a transmissivity, a black mask formed so as to divide display pixels in parallel with the transparent electrodes, and a transparent electrode and a black mask having a visible light transmissivity. The step of forming the transparent electrode and the black mask includes a black mask forming portion, and does not cover a discharge gap portion formed at the center of each transparent electrode. Forming a photosensitive black mask material in a strip shape, forming a photoresist layer on the entire surface of the substrate, and simultaneously forming the photosensitive black mask material and the photoresist. Exposing using a transparent electrode-shaped mask, developing the photosensitive black mask material and photoresist, forming a transparent conductive film over the entire surface of the substrate, removing the photoresist, Baking a photosensitive black mask material to form a black mask. 2. The method according to claim 1, wherein the photosensitive black mask material and the photoresist are of a negative type in which both exposed portions remain after development. 3. The method according to claim 1, wherein the photosensitive black mask material and the photoresist are of a positive type in which portions that are not exposed to light remain after development. 4. The method according to claim 1, wherein the method of applying the photosensitive black mask material is based on a screen printing method. 5. The method of claim 1, wherein the photosensitive black mask material is applied by a dispenser method. 6. A method for producing a photosensitive black mask material, comprising:
2. The method according to claim 1, wherein the photoresist is carbonized and removed.