JP3229640B2 - Method for forming phosphor screen of plasma display panel and phosphor slurry for plasma display panel used therefor - 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 fluorescent screen of a plasma display panel (hereinafter, referred to as PDP) which is a self-luminous flat panel display using gas discharge.

[0002]

2. Description of the Related Art FIG. 2 shows an example of the configuration of a conventional DC PDP. As shown in the figure, in this DC-type PDP, 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 provided between them. It is held at a certain interval by the cell barrier 13. An anode 14 is formed on the back side of the front plate 11, a cathode 15 is formed on the front side of the back plate 12 at right angles to the anode 14, and a fluorescent screen is formed on both sides of the anode 14. 16 are formed adjacent to each other. In this DC type PDP, the anode 14
By applying a predetermined voltage from a DC power supply between the power supply and the cathode 15 to form an electric field, each cell 17 as a display element composed of the front plate 11, the back plate 12 and the cell barrier 13 is formed.
The discharge is performed inside. The ultraviolet light generated by the discharge causes the fluorescent screen 16 on the back side of the front plate 11 to emit light, so that the light transmitted through the front plate 11 can be visually recognized by an observer.

FIG. 3 shows a configuration example of a conventional AC PDP. As shown in FIG.
In the C-type PDP, similarly to the DC-type PDP, a flat front plate 21 and a rear plate 22 made of glass are arranged in parallel and opposed to each other, and both are provided between them. It is held at a fixed interval by the cell barrier 23. In this AC type PDP, two electrodes 24 and 25 orthogonal to each other are formed on the front side of the back plate 22 via a dielectric layer 26, and further on the front side, a dielectric layer 27 and a protective layer 28 are formed. Are formed, and a fluorescent screen 29 is formed on the back side of the front plate 21. In this AC type PDP, two electrodes 2
By applying a predetermined voltage from an AC power supply between the power supply plates 4 and 25 to form an electric field, the front plate 21 discharges inside each cell 30 as a display element composed of the back plate 22 and the cell barrier 23. Done. The ultraviolet light generated by the discharge causes the fluorescent screen 29 on the back side of the front plate 21 to emit light, so that the light transmitted through the front plate 21 can be visually recognized by an observer.

Here, the shape of the cell barrier includes a matrix shape and a line shape.
In the case of a type PDP, FIG. 4 shows a matrix type and FIG. 5 shows a line type. 4 and 5, reference numeral 31 denotes a front plate disposed on the viewer side, 32 denotes a rear plate, 33 denotes a cell barrier, 34 denotes an anode, and 35 denotes a cathode. In addition, although the cell barrier 33 is formed on the back plate 32 when forming the PDP in these figures, the cell barrier 33 may be formed on the front plate 31 in some cases.

[0005] Then, the DC type or A having the structure as described above is used.
The phosphor screen of the C-type PDP is generally formed by a photolithography method. Specifically, a photosensitive phosphor slurry is applied to the back surface of the front plate, and then a photomask corresponding to the pattern of the phosphor screen is used. Exposure, development, and baking. As the phosphor slurry, a mixture containing a phosphor and polyvinyl alcohol (PVA) and a diazonium compound as a photosensitive resin, or a mixture containing a phosphor and PVA and a dichromate compound as a photosensitive resin is mainly used. In some cases, an antifoaming agent or a surfactant may be added.

Further, in the above-mentioned PDP, there is also known a PDP in which a phosphor screen is formed on a wall surface of a cell barrier, and a PDP in which a phosphor screen is formed over both a front plate and a wall surface of a cell barrier. In this case, the phosphor screen is also formed by a photolithography method.

[0007]

However, when the phosphor screen is formed by the photolithography method described above, a Ni electrode formed by thick film printing (for example, when using 9535 or 9536D manufactured by DuPont as a paste) Is formed on a glass substrate, the phosphor slurry of PVA-based phosphor due to boric acid generated by oxidation of boron in the electrode paste at the time of firing, particularly sodium borate generated by reaction with sodium contained in the glass substrate or paste. Has solidified in a gel-like state, and it has been impossible to perform patterning accurately.

[0008] Materials for forming electrodes and cell barriers include boron, copper, aluminum, titanium, zirconium, and the like.
When tin, vanadium, chromium, etc. are contained, or when aldehydes, methylol compounds, activated vinyl groups, epoxy compounds, esters, diisocyanates, etc. remain on the electrodes and cell barriers, PVA-based The phosphor slurry solidifies at the time of coating, so that accurate patterning cannot be performed or a uniform film thickness cannot be ensured.

Further, in order to improve the adhesive strength between the phosphor and the glass substrate, powder glass having a low melting point (generally, lead borosilicate glass) is mixed with the phosphor slurry. When powdered glass having a ratio of 1.5% or more is used, gelling of the PVA-based phosphor slurry occurs, so that the low-melting glass that can be used is very limited.

As described above, there is a problem that the photolithography process for forming the fluorescent screen is hindered depending on the material for forming the electrodes and the cell barrier or the type of the low melting point glass in the PVA-based phosphor slurry.

The present invention has been made in order to solve such a problem, and it is possible to accurately and irrespective of the type of material used in the pre-process and the type of low melting point glass mixed with the phosphor slurry. An object of the present invention is to provide a method for forming a phosphor screen of a PDP, which can easily form a phosphor screen.

[0012]

In order to achieve the above-mentioned object, the present invention provides a method of applying a phosphor slurry obtained by dispersing a phosphor in a photosensitive resin composition to a surface on which a phosphor screen is to be formed. A method of forming a phosphor screen at a predetermined place through exposure, development and baking steps, wherein the photosensitive resin composition comprises casein and an organic curing agent as essential components.
And the organic curing agent casein
Amount of the casein is 20 wt% or more, and
The addition ratio of the phosphor is 10 to 100 per part by weight of casein.
It is characterized in that it is part by weight .

The organic curing agent is preferably a bisazide curing agent.

In the above method, the phosphor slurry is preferably applied by a doctor blade coating method.

When a color PDP is formed by the above-described method, the phosphors respectively emitting red, green, and blue light are subjected to phosphor slurry application, selective exposure through a mask, and development. You just have to repeat it.

[0016]

According to the method for forming the phosphor screen of the present invention, the phosphor screen is not affected by the material of the electrodes and cell barriers formed on the substrate or the low melting point glass mixed in the phosphor slurry. A photolithography step of formation is performed.

[0017]

FIG. 1 is a process diagram showing an embodiment of a method for forming a phosphor screen of a PDP according to the present invention, in which a phosphor screen is formed on the same plane as an electrode formed on a front plate of a DC PDP. Is shown. Hereinafter, the respective steps shown in FIGS. 1A to 1E will be described in order.

First, as shown in FIG. 1A, an anode 2 is formed in a thick or thin film state on a substrate 1 made of ceramic such as glass. Then, as shown in (b),
A phosphor slurry 3 made of a photosensitive resin composition in which a phosphor is dispersed is applied to a surface of the substrate 1 on which a phosphor surface is to be formed by an arbitrary coating method, and dried. Thereafter, as shown in (c), after pattern exposure with ultraviolet rays 5 through a phosphor pattern mask 4, as shown in (d), the unexposed portion of the unexposed portion is left while developing and patterning the phosphor layer 6. Remove layer and dry.

Here, in the case of a color PDP, phosphors having emission colors of red, green and blue, respectively, are selectively applied through application of a photosensitive resin composition containing the phosphor and a mask of the phosphor pattern. Each step of removing the unexposed portions and excess phosphor by exposure and development is repeated.

Finally, the phosphor layer 6 thus formed is baked to burn off the resin component and the organic curing agent of the phosphor slurry, thereby obtaining a desired pattern of fluorescent light as shown in FIG. Surface 7 is formed.

In addition to the front plate on which the fluorescent screen 7 is formed, a rear plate on which a cathode and a cell barrier are formed is prepared. By combining these front and rear plates, a PDP is formed. You.

All of the above manufacturing steps may be the same as those of the conventional method. Therefore, the electrode forming method, the substrate material, the coating method, the developing method and the firing method to be used may be the same as those of the conventional method. However, in the present invention,
A photosensitive resin composition comprising casein and an organic curing agent is used.

As the casein, any of the conventionally known caseins can be used.

On the other hand, examples of the organic curing agent include diazonium salts, phenylazides, o-quinone azides,
Any of conventionally known organic curing agents such as bisazides can be used, but from the viewpoint of curability, developability, baking properties, etc., bisazide curing agents are suitable, and particularly useful ones are 4.4. '-Diazido stylbene-2.2'disulfonic acid
It is.

The addition amount of such an organic curing agent to casein is preferably 20% by weight or more of casein.
That is, if the content is less than 20% by weight, the casein is insufficiently cured, and the film may float during development. In addition, if the amount of the curing agent is excessively large, only the surface layer is cured by coloring of the curing agent, resulting in poor curing as a whole, or a significant decrease in sensitivity, so that the film thickness cannot be obtained for the exposure amount. A phenomenon occurs.

The photosensitive resin composition used in the present invention comprises the above-mentioned casein and an organic curing agent as essential components, and may further contain any of the conventionally known additives as necessary. In the present invention, the above essential components and optional additives are formed into a coating liquid by mixing water or a water-soluble organic solvent such as alcohol with water and ammonia for adjusting pH. The amount of solvent used varies depending on the type of casein used, the concentration of the phosphor and the coating method, but in general,
The range of 20 to 80 wt% is good.

The phosphors that can be used in the present invention include Y ₂ O ₃ : Eu, Y ₂ SiO ₅ : Eu,
Y ₃ Al ₅ O ₁₂ : Eu, Zn ₃ (PO ₄ ) ₂ : Mn, Y
BO ₃ : Eu, (Y, Gd) BO ₃ : Eu, GdB
O ₃ : Eu, ScBO ₃ : Eu, LuBO ₃ : Eu, etc., and Y ₂ SiO ₅ : Ce, CaWO ₄ : P
b, BaMgAl ₁₄ O ₂₃ : Eu, etc.
n ₂ SiO ₄ : Mn, BaAl ₁₂ O ₁₉ : Mn, SrAl
_{13 O 19: Mn, CaAl 12} O 19: Mn, YBO 3: T
b, BaMgAl ₁₄ O ₂₃ : Mn, LuBO ₃ : Tb, G
dBO ₃ : Tb, ScBO ₃ : Tb, Sr ₆ Si ₃ O ₃
Cl ₄ : Eu and the like.

Such a phosphor is preferably added at a ratio of about 10 to 100 parts by weight per 1 part by weight of the casein.
More preferably, it is added in a proportion of 33 to 80 parts by weight. At this time, care must be taken because if the amount of resin is large, the amount of exposure required for curing becomes extremely large, resulting in deterioration of the shape and insufficient film thickness.

For dispersing the phosphor 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. In the present invention, a ball mill is particularly useful.

As a method of applying a phosphor slurry comprising a photosensitive resin composition in which the above-mentioned phosphor is dispersed on a substrate on which a desired electrode is provided, there are a doctor blade coating method, a miller bar coating method, and a roll coating method. Any of known coating methods such as a screen coating method, a screen printing method, and a spinner coating method can be used.However, entrapment of air bubbles, prevention of sedimentation of a phosphor, prevention of electrode damage by an uneven electrode substrate, The doctor blade coating method is most suitable from the viewpoints of mixing of air bubbles and uniformity of the applied amount. In particular, the electrodes on the substrate are generally formed in the form of stripes. In coating, it is preferable that coating is performed by moving a doctor blade along the stripes. A smooth and uniform coating can be realized without problems such as mixing of air bubbles, damage to electrodes, and uneven coating.
The coating film formed as described above varies depending on the thickness of the electrode, but is generally about 5 to 50 μm when dried.
The degree is preferred.

The respective steps such as drying of the coating film, curing by patterning exposure, elution of the unexposed portion by development, and baking, and the conditions thereof, have already been described and are exemplified in the specific examples described later. There is no limitation, and it may be the same as in the prior art.

Although the DC type PDP has been described above, it is apparent that the same applies to an AC type PDP.

Next, a specific example of the above embodiment will be described in detail below.

[Specific Example] On a glass substrate serving as a front plate,
An Ni electrode was printed at a width of 150 μm and a pitch of 500 μm with a Ni paste (manufactured by DuPont, 9536D) by a screen printing method, dried, and then fired at 580 ° C. in the air to form an anode. After washing the substrate, a phosphor having a green emission color (Zn ₂ S, manufactured by Kasei Optonics, Inc.)
iO ₄ : Mn): 30.0 wt%, casein sulfate: 8.
21 wt%, pure water: 60.8 wt%, borax: 0.5 wt
%, Sodium citrate: 0.035 wt%, Deltop 100: 0.21 wt%, 28% ammonia water: 0.1%
4.4'-Diazido stylbene-2.2 'in a mixture consisting of 245%
A phosphor slurry obtained by adding 55% by weight of casein to disulfonic acid (A-066, manufactured by Shinko Giken Co., Ltd.)
The whole surface is coated with a blade coater at 30 ° C. so as to cover the electrodes, and dried at room temperature.
52.5 mJ / cm ^{2 of} ultraviolet light having a maximum wavelength near m
And exposure was performed. At this time, irradiation was performed from the back side of the substrate so that a fluorescent screen was not formed on the electrode. Next, the substrate was spray-developed with water to remove unexposed portions. Thereafter, the film was dried at 120 ° C. to form a hardened film. Subsequently, a cell having a phosphor screen having a blue emission color (phosphor: BaMgAl ₁₄ O ₂₃ : Eu) and a cell having a phosphor screen having a red emission color (phosphor: (Y, Gd) BO ₃ : E
u), the above steps were repeated in the same manner, and calcined at about 440 ° C. for 30 minutes to obtain a resin component (casein) in the slurry and a curing agent (4.4′-Diazido stylbene-2.2′disulfate).
onic acid), and red,
A green and blue phosphor screen was formed.

By combining the front plate on which the above-mentioned fluorescent screen is formed and the rear plate on which a cathode and a cell barrier are separately formed, a matrix color PDP in which three primary colors of red, green and blue are visually recognized is formed. PD created in this way
In P, a phosphor screen is formed on the back side of the front plate, and the phosphor screen is excited by ultraviolet rays by plasma discharge to emit light, so that an observer can visually recognize the transmitted light of the phosphor screen.

It is needless to say that a PDP having a structure having a linear cell barrier as shown in FIG. 5 can be formed in the same process.

[0037]

As described above, the method for forming a phosphor screen of a plasma display panel according to the present invention provides a phosphor obtained by dispersing a phosphor in a photosensitive resin composition containing casein and an organic curing agent as essential components. so as to form a phosphor screen in place by a photolithography method using a slurry, deer
Also, the amount of organic hardener added to casein
20 wt% or more, and addition of a phosphor
The ratio is 10 to 100 parts by weight per 1 part by weight of casein.
As a result, a phosphor screen that is accurately patterned and has a uniform film thickness can be formed regardless of the materials of the electrodes and cell barriers used in the previous step. Therefore, it is possible to use an existing paste for an electrode or paste for a cell barrier, the use of which has been restricted because of difficulty in forming a phosphor screen due to products and residues.

Further, even when a low-melting glass is mixed with a phosphor slurry in order to improve the adhesive strength between the phosphor and the glass substrate, the components in the low-melting glass do not hinder the photolithography process. The range of possible low-melting glass is widened.

Further, by applying the phosphor slurry by a doctor blade coating method in combination with the above method, even if the substrate is large, for example, a metric size substrate, and even if the substrate surface is roughened by electrodes, A coating having a uniform film thickness can be realized over the entirety.

Further, by selectively forming the phosphor screen with the respective phosphors having red, green and blue emission colors, color display is possible.

[Brief description of the drawings]

FIG. 1 is a process diagram showing one embodiment of a method for forming a phosphor screen of a plasma display panel according to the present invention.

FIG. 2 is a partial cross-sectional view illustrating an example of a DC type plasma display panel.

FIG. 3 is a partial cross-sectional view illustrating an example of an AC type plasma display panel.

FIG. 4 is a partially cutaway perspective view showing a DC type plasma display panel having a matrix of cell barriers in a state where a front plate and a back plate are separated from each other.

FIG. 5 is a partially cutaway perspective view showing a DC type plasma display panel having a line-shaped cell barrier in a state where a front plate and a back plate are separated from each other.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Electrode 3 Phosphor slurry 4 Mask 5 Ultraviolet 6 Phosphor layer 7 Phosphor screen

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01J 9/227 H01J 11/02

Claims (6)

(57) [Claims] A phosphor slurry obtained by dispersing a phosphor in a photosensitive resin composition is applied to a surface on which a phosphor surface is to be formed, and the phosphor surface is formed in a predetermined place through exposure, development and baking steps. in the fluorescent screen forming method of the plasma display panel to form, together with the photosensitive resin composition has a casein and organic curing agent to essential components, the organic hardness
20 wt% of casein
And the addition ratio of the phosphor is 1 weight of casein.
A method for forming a phosphor screen of a plasma display panel , wherein the amount is 10 to 100 parts by weight per part . 2. The method according to claim 1, wherein the organic curing agent is a bisazide curing agent. 3. The method for forming a phosphor screen of a plasma display panel according to claim 1, wherein the phosphor slurry is applied by a doctor blade coating method. 4. The method according to claim 1, wherein the application of the phosphor slurry, the selective exposure through a mask, and the development are repeated for the phosphors having red, green, and blue emission colors, respectively. 4. The method for forming a phosphor screen of a plasma display panel according to 3. 5. A phosphor slurry obtained by dispersing a phosphor in a photosensitive resin composition, the photosensitive resin composition when has a <br/> casein and organic curing agent essential ingredients together
The amount of organic hardener added to casein
20% by weight or more of the phosphor and the proportion of the phosphor added
Is 10 to 100 parts by weight per 1 part by weight of casein . 6. The phosphor slurry for a plasma display panel according to claim 5, wherein the organic curing agent is a bis azide curing agent.