JPH1161486A - Electrodeposition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily form thin wall-like electrodeposition films each of which is used as a partition wall and has a sufficient height and a narrow width, such as to enable the formation of a cell excellent in independence with respect to selective discharge light-emission, with high accuracy by forming slits in a counter electrode for forming the electrodeposition films, at the time of manufacturing a plasma display panel. SOLUTION: In this method, a counter electrode 4 is placed so as to face toward an insulting glass substrate 1 on which linear electrically conductive films 2 are formed, while interposing an electrodeposition solution between them, to form electrodeposition films on the conductive films 2, respectively. At this time, the counter electrode 4 used, consists of: an insulating plate 6 in which slits 6A corresponding to the conductive films 2 on the glass substrate 1, that the electrodeposition films are to be formed respectively on, are formed; and also, an electrode films 5 is formed on one surface of the insulating plate 6; wherein the other surface of the insulating plate 6, on which no electrode film is formed, is placed so as to face toward the surface of the glass substrate 1, that the conductive films 2 are formed on. The height/ width ratio of each of the thin wall-like electrodeposition films formed with the counter electrode 4 is about 3/5. Also, the manufacture of this counter electrode 4 comprises: forming the slits 6A in the insulating plate 6 by using a laser processing method or the like; and thereafter, forming the electrode film 5 made of a noble metal such as Au or Ag by using a sputtering method or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrodeposition method, and more particularly to an electrodeposition method suitable for forming a partition on a substrate of a plasma display panel.

[0002]

2. Description of the Related Art Plasma display
Is an image display device using gas discharge, and usually,
A large number of minute discharge cells are arranged vertically and horizontally (in a matrix), and a required portion of cells is discharged to emit light to display characters and figures. The flat display panel is called a plasma display panel (PDP). The plasma display panel has a simple structure and can be easily enlarged; it has a memory function; it can be colored;
Because of these advantages, PDPs that are much larger and have a smaller depth than cathode-ray tubes used in televisions and the like are being researched.

FIG. 4 is an exploded perspective view showing a general structure of a plasma display panel. In the drawing, reference numeral 21 denotes a surface glass substrate, a display electrode 22, a dielectric layer 23, and a protective film 24 such as MgO (magnesium oxide). Is provided. 2
Reference numeral 5 denotes a rear glass substrate on which partition walls 26 are formed at predetermined intervals. An address electrode 27 and a phosphor 28 are formed in a fine space (discharge cell) defined by the front glass substrate 21, the rear glass substrate 25, and the partitions 26, 26, and a discharge gas is injected.

In the production of this plasma display panel, it is necessary to accurately form relatively high partition walls capable of forming discharge cells having excellent independence capable of performing selective discharge light emission. Is extremely important in terms of display characteristics.

Conventionally, the partition walls of a plasma display panel are formed by forming address electrodes in a predetermined pattern on a glass substrate, applying an inorganic paste made of ceramic or glass by a screen printing method, and then firing. , A width of about 70 μm and a height of 100 to 150 μm. In this method, printing and baking are repeated several tens of times to form a partition requiring a height of 100 μm or more. If not, the desired height cannot be formed with high accuracy, and the manufacturing efficiency is poor.
There is a drawback that the positional accuracy and height accuracy of the partition walls to be formed are poor due to the limit of the processing accuracy of the screen printing plate and the like.

As a method of solving such a problem and forming a partition of a plasma display panel easily and with high precision, the present applicant has proposed a method of forming a partition on a glass substrate (back glass substrate) in a portion where a partition is to be formed. After forming the conductive film, the conductive film and the counter electrode are arranged via an electrodeposition solution made of a slurry of glass powder, and a DC voltage is applied between the conductive film and the counter electrode to form the conductive film. A method has been proposed in which a glass layer is electrodeposited thereon and then fired to form partition walls (JP-A-9-17).
No. 1769). By forming the partition walls by the electrodeposition method in this way, it is possible to form the partition walls with high efficiency, high positional accuracy, and high height accuracy.

In the conventional electrodeposition method, a plate-like electrode such as an aluminum plate or a mesh-like electrode is used as the counter electrode.

[0008]

In order to manufacture a highly fine plasma display panel, the partition walls must be formed as follows.
It is necessary to have a thin wall shape having a predetermined height and a narrow width, but there is a disadvantage that such a partition cannot be formed by the conventional electrodeposition method.

That is, in the conventional electrodeposition method using a plate-shaped or mesh-shaped counter electrode, an electric field is concentrated on an edge portion of a linear conductive film. The electrodeposition film is grown in the width direction at substantially the same distance as the height direction (in FIG. 3A, reference numeral 11 denotes a glass substrate,
2 denotes a linear conductive film, and 13 denotes the formed electrodeposition film. ).

In general, in a plasma display panel, the height h of an electrodeposition film as a partition is required to be about 200 μm, and therefore, in the conventional electrodeposition method, the width w _{1 is} 50 μm.
Is formed, and a height h = h
When the electrodeposited film 13 having a thickness of 200 μm is formed, the width W of the formed electrodeposited film 13 is theoretically 450 μm (w = w ₁ + w).
₂ × 2 ≒ w ₁ + h × 2 = 50 + 200 × 2 = 450),
In practice, it will be much wider.

The present invention solves the above-mentioned problems of the conventional electrodeposition method, and provides an electrodeposition method capable of easily and accurately forming a thin-walled electrodeposition film having a small width with respect to the height. The purpose is to do.

[0012]

According to the electrodeposition method of the present invention, a counter electrode is opposed to a conductive film forming surface of an insulating substrate having a linear conductive film formed on a plate surface via an electrodeposition liquid. And applying a DC voltage between the conductive film and the counter electrode to form an electrodeposited film on the conductive film, wherein the counter electrode is located at a position corresponding to the conductive film on the insulating substrate. An insulating plate in which a slit is formed and an electrode film is formed on one surface is used, and the other surface of the counter electrode is arranged to face the conductive film.

As shown in FIG. 3B, in the conventional electrodeposition method using the plate-shaped or mesh-shaped counter electrode 14, the electric field concentrates on the edge of the conductive film 12 formed on the glass substrate 11. As shown in FIG. 3 (a), the formed electrodeposition film 13 became wide and a thin-walled electrodeposition film could not be formed.

On the other hand, in the electrodeposition method of the present invention, as shown in FIG. 1B, a slit 6 is formed at the position corresponding to the conductive film 2 of the glass substrate (insulating substrate) 1 as the counter electrode 4.
A is formed, and an insulating plate 6 having an electrode film 5 formed on one surface is used, and an insulating surface 4A on a side where the electrode film 5 is not formed is opposed to the conductive film 2 to perform electrodeposition. Is performed, the concentration of the electric field on the edge portion of the conductive film 2 is reduced, and as shown in FIG. 1A, even if the height h is increased, the thin-walled electrodeposition film 3 having a small width W is formed. Can be formed.

As described above, the reason why the concentration of the electric field on the edge portion of the conductive film 2 is reduced is that the electrodeposition liquid (the dispersion medium of the electrodeposition liquid) has a higher electric flux density than the insulating plate 5. It is presumed that the height increases in the slit 6 </ b> A where there is, and decreases on the insulating plate 6 side.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1A is a cross-sectional view showing an embodiment of an electrodeposition film formed by the electrodeposition method of the present invention, and FIG. 1B illustrates the state of an electric field in the electrodeposition method of the present invention. It is a typical sectional view. FIG. 2 is a perspective view showing an embodiment of the electrodeposition method of the present invention.

In the electrodeposition method of the present invention, as shown in FIG.
The counter electrode 4 faces the insulating substrate such as the glass substrate 1 on which the linear conductive film 2 is formed via an electrodeposition liquid, and a DC voltage is applied between the conductive film 2 and the counter electrode 4. As shown in FIG. 1, an electrodeposition film 3 is formed on the conductive film 2.

In FIG. 2, reference numeral 7 denotes a collecting electrode of the conductive film 2, and reference numeral 8 denotes a DC power supply.

In the present invention, as the counter electrode 4, a slit 6A is formed so as to correspond to the conductive film 2 of the glass substrate 1 on which an electrodeposition film is formed, and the electrode film 5 is formed on one surface. The counter electrode 4
Electrodeposition is performed by arranging the surface 4A on which the electrode film is not formed to face the conductive film 2 formation surface of the glass substrate 1.

As a material of the insulating plate 6 constituting the counter electrode 4, a material having a lower relative dielectric constant than the dispersion medium of the electrodeposition liquid is preferable, and for example, alumina, fluororesin or the like can be used.

When the glass substrate 1 and the counter electrode 4 face each other, the slit 6A
It is formed so that the projected surface onto the conductive film 2 overlaps, more preferably, the center line of the slit 6A and the center line of the conductive film 2 overlap.

The electrode film 5 formed on one surface of the insulating plate 6 of the counter electrode 4 is made of gold (Au) or silver (Ag).
Noble metal films with high conductivity such as are preferred.

Such a counter electrode 4 can be easily manufactured by forming a slit 6A on the insulating plate 6 by laser processing or the like, and then forming the electrodeposition film 5 on one surface by a sputtering method or the like.

In the present invention, by using such a counter electrode, a thin-walled electrodeposited film having a height / width ratio of about 3/5 can be easily and efficiently placed at a desired position. , Can be formed with high precision.

In the present invention, the conductive film 2 may be formed on an insulating substrate such as the glass substrate 1 by directly printing a thick film paste for forming a conductive film and baking the conductive film. A method in which a resist film as a film formation preventing layer is formed in a predetermined pattern in a film non-formed portion, and then a conductive film is formed on the resist film non-formed surface is preferable. In order to form the resist film in a predetermined pattern, an ordinary method may be used, such as attaching an organic resist in the form of a film, exposing the organic resist to a predetermined pattern, and then removing an unexposed portion. After a conductive film is deposited on the substrate on which the resist film of the predetermined pattern is formed by various methods such as sputtering, CVD, ion plating, and printing, the resist film is dissolved and removed with a solvent to form a linear pattern only on necessary portions. The substrate on which the conductive film is formed is obtained.

In particular, when a partition of a plasma display panel is formed, the conductive film is made of Ag (silver), A
l (aluminum), and the thickness of the conductive film is 20
It is preferably in the range of 0-2000 °, especially 300-1000 °.

As the electrodeposition liquid, a slurry in which powder of an electrodeposition film forming material such as glass powder is dispersed in a dispersion medium is used. In particular, when forming the partition of the plasma display panel, the glass powder has a softening temperature of 500.
PbO-based glass powder having a temperature of at most 450C (particularly 450-490C) is preferred. An example of a suitable glass composition is Pb
O: 20~80 weight%, SiO _2: 10~20% by weight,
B ₂ O ₃ : 10 to 30% by weight.

The average particle size of the powder is 1.0 to 5.0 μm.
In particular, 2.5 to 3.0 μm is preferable.

As a dispersion medium for dispersing this powder, I
It is preferable that water is added to PA (isopropyl alcohol) and further an acid is added to improve the electrodeposition property.
The addition amount of the acid is preferably 0.1 to 0.5% by volume.

In the present invention, the glass substrate 1 on which the conductive film 2 is formed and the counter electrode 4
Are immersed and arranged so that the conductive film 2 and the electrode film non-formed surface 4A of the counter electrode 4 face each other, and the conductive film 2 and the slit 6A of the counter electrode 4 are spaced from each other. A DC voltage of about 300 to 800 V (positive for the conductive film 2) is applied between the film 2 and the counter electrode 4 to form the electrodeposition film 3 on the conductive film 2.

After the electrodeposition film 3 is formed at a desired height, the glass substrate is taken out, dried, and fired in an oxidizing atmosphere.

[0033]

The present invention will be described more specifically below with reference to examples and comparative examples.

Example 1 A glass substrate having a size of 100 mm × 100 mm and a thickness of 3 mm was coated with A
g By printing and baking the thick film paste,
A 3 μm, 95 mm long, 50 μm wide linear conductive film is
The center pitch (the distance between the center lines of adjacent linear conductive films) was 1 mm.

On the other hand, on a 0.5 mm thick alumina substrate,
After forming a slit having a length of 95 mm and a width of 100 μm at a center pitch (interval between center lines of adjacent slits) of 1 mm by laser processing, an Au film having a thickness of 500 ° was formed by sputtering on one surface to form a counter electrode. .

As the electrodeposition liquid, glass powder ("GA-1" manufactured by Nippon Electric Glass) was used, 100 parts by volume of IPA, 2.5 parts by volume of acetic acid, 0.1 part by volume of water, and a nonionic surfactant. A solution (20 g / L) dispersed in 0.8 volume parts of a solution (0.05 g / cc methanol solution of "HCO-100" manufactured by Nikko Chemicals Co., Ltd.) was used.

As shown in FIG. 2, A of the glass substrate is adjusted so that the Ag film of the glass substrate and the slit of the counter electrode correspond to each other (so that the center line of the Ag film coincides with the center line of the slit).
The g film forming surface and the Au electrode non-forming surface of the opposing electrode are arranged to face each other (the distance between the glass substrate and the opposing electrode is 0.4 mm).
Electrodeposition was performed by applying a direct current of 300 V for 1 minute between the counter electrode and the Ag film on the glass substrate.

As a result, a width of 530 μm and a height of 330 μm
Was formed. Similar results were obtained even when the distance between the glass substrate and the counter electrode was changed in the range of 0.4 to 2 mm.

Comparative Example 1 Electrodeposition was performed in the same manner as in Example 1 except that a SUS mesh electrode was used as the counter electrode. The electrodeposited film formed was 600 μm wide and 150 μm high.
m of the electrodeposited film.

[0040]

As described in detail above, according to the electrodeposition method of the present invention, a thin wall-shaped electrodeposition film having a small width and a high height can be accurately formed.

For this reason, by adopting the electrodeposition method of the present invention for forming the partition walls of the plasma display panel,
It is possible to easily manufacture a highly fine plasma display panel.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view showing an embodiment of an electrodeposition film formed by the electrodeposition method of the present invention, and FIG. 1B is a view illustrating the state of an electric field in the electrodeposition method of the present invention. FIG.

FIG. 2 is a perspective view showing an embodiment of the electrodeposition method of the present invention.

FIG. 3A is a cross-sectional view illustrating an electrodeposition film formed by a conventional electrodeposition method, and FIG. 3B is a schematic cross-sectional view illustrating a state of an electric field in the conventional electrodeposition method. It is.

FIG. 4 is an exploded perspective view showing a general configuration of a plasma display panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 11 Glass substrate 2, 12 Conductive film 3, 13 Electrodeposition film 4, 14 Counter electrode 5 Electrode film 6 Insulating plate 6A Slit 21 Surface glass substrate 22 Display electrode 23 Dielectric layer 24 Protective film 25 Back glass substrate 26 Partition 27 Address electrode 28 Phosphor

Claims (2)

[Claims] 1. A counter electrode is opposed to a conductive film forming surface of an insulating substrate having a linear conductive film formed on a plate surface thereof through an electrodeposition liquid, and between the conductive film and the counter electrode. In an electrodeposition method of forming an electrodeposition film on the conductive film by applying a DC voltage, a slit is formed as the counter electrode at a position corresponding to the conductive film on the insulating substrate, and an electrode is formed on one surface. An electrodeposition method, comprising using an insulating plate on which a film is formed, and disposing the other surface of the counter electrode so as to face the conductive film. 2. The electrodeposition method according to claim 1, wherein the relative permittivity of the insulating plate of the counter electrode is smaller than the relative permittivity of the dispersion medium of the electrodeposition liquid.