JPH11120923A - Plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma display panel(PDP) preventing the electric field applied between discharge electrodes at the start of a plasma discharge from being leaked to adjacent discharge display cells, reducing the drive current between the discharge electrodes and address electrodes, having many high- precision discharge display cells showing stable and accurate luminous display, and capable of easily obtaining a large screen up to 30 in, for example. SOLUTION: Multiple discharge display cells 5 are formed by barrier ribs 4 partitioning the space between a pair of insulating substrates forming a back plate 2 and a front plate 3, and the dielectric constant of the barrier ribs 4 is made higher near the front plate 3 on discharge electrodes 6 side than at least near the back plate 2 on address electrodes 7 side. Multiple electrodes 6, 7 are provided in the discharge display cells 5, discharge gas is airtightly sealed in the discharge display cells 5, a voltage is selectively applied between the electrodes 6, 7 to generate plasma, and phosphors 8 formed on the inner walls of the discharge display cells 5 are illuminated to form the light emitting element of an image display device.

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 (hereinafter, referred to as a "light-emitting element") used in a high-precision, inexpensive, lightweight, thin, large-screen color image display device or the like.
PDP).

[0002]

2. Description of the Related Art CRTs, which have been widely used as image display devices, have a disadvantage that they have a large volume and weight and require a high voltage.
Light emitting diode (LE) as information interface
D), a liquid crystal display device (LCD), or a flat-panel image display device that has features such as a large screen such as a PDP and the like, and has a feature that it is lightweight, thin, and can be installed anywhere. I am doing it.

Among flat-panel image display devices that meet such demands, PDPs utilizing plasma emission have attracted attention as light-emitting elements of color image display devices for large screens.

Such a PDP comprises a pair of flat insulating substrates forming a back plate 21 and a front plate 22 as shown in FIG.
A minute space surrounded by a partition wall 23 that partitions the space is defined as a discharge display cell 24. Plasma is generated by discharge between the pair of discharge electrodes 25 in the discharge display cell 24 and the discharge electrode 25 at the bottom thereof. An address electrode 26 for generating and switching light emission of the discharge display cell 24 is provided, and has a structure in which a dischargeable gas such as a rare gas is hermetically sealed in the space, and between the opposed electrodes 25 and 26. A plasma is generated by discharge by selectively applying a voltage, and ultraviolet light emitted from the plasma causes the phosphor 27 formed in the discharge display cell 24 to emit light, which is used as a light emitting element of an image display device. is there.

The barrier ribs constituting such a discharge display cell are mainly composed of, for example, a lead-based low-melting glass which can be fired at a low temperature below the softening point of the glass forming the insulating substrate. Filler components, etc., and coloring agents for improving the luminous quality, that is, white colorants for improving the light reflectivity of the partition walls to increase the brightness, or for providing light absorbing properties to the partition walls and adjacent light emitting displays Since it is made of a material to which a black colorant or the like is added to prevent color mixing of cells and improve the contrast ratio of PDP, its dielectric constant is 1
About 2 to 16 were shown.

Therefore, the capacitance of the discharge display cell becomes large because it is proportional to the dielectric constant of the insulating dielectric which forms the partition between the corresponding electrodes, and the driving voltage between the discharge electrode and the address electrode becomes large. There is a problem in that the current becomes large, the power consumption of the PDP becomes large, and the power supply equipment becomes large.

Therefore, in order to reduce the drive current flowing between the discharge electrode and the address electrode and to solve the above-mentioned problem, at least the partition wall insulating the discharge electrode and the address electrode is made of a dielectric material having a low dielectric constant. It has been proposed to configure (see Japanese Patent Publication No. Hei 7-24189).

[0008]

However, in the above proposal, since the entire partition is made of a dielectric material having a low dielectric constant, the capacitance of the discharge display cell is reduced and the current at the time of driving is reduced. If the capacitance between discharge electrodes adjacent to each other across a partition is equal to or smaller than the capacitance between discharge electrodes in one discharge display cell, the discharge display cell selected at the start of plasma discharge There is a problem that an electric field applied between the discharge electrodes inside leaks to an adjacent discharge display cell to cause erroneous discharge, and stable and accurate light-emitting display cannot be performed.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and an object of the present invention is to prevent an electric field applied between discharge electrodes at the start of plasma discharge from leaking to an adjacent discharge display cell. An object of the present invention is to provide a PDP which has a large number of high-definition discharge display cells capable of obtaining a stable and accurate light-emitting display by reducing a drive current between the display electrodes and an address electrode, and which can easily have a large screen.

[0010]

The present inventors have conducted intensive studies in view of the above-mentioned problems, and as a result, the dielectric constant of the partition wall constituting each discharge display cell by insulating the discharge electrode and the address electrode has been reduced on the discharge electrode side. By being formed to be higher than the address electrode side, it is possible to prevent the electric field applied between the discharge electrodes from leaking to the adjacent discharge electrode, and to set the dielectric constant of the partition wall on the address electrode side to lower the discharge. The inventors have found that the drive current between the electrode and the address electrode can be reduced, and have reached the present invention.

That is, in the PDP of the present invention, a plurality of discharge display cells are constituted by a pair of insulating substrates forming a back plate and a front plate, and partition walls partitioning a space between the insulating substrates. A partition is formed so as to be higher at least in the vicinity of the front plate on the discharge electrode side than in the vicinity of the rear plate on the address electrode side, a plurality of electrodes are provided in the discharge display cell, a discharge gas is hermetically sealed, and a voltage is applied between the electrodes. Is selectively applied to generate plasma, and the phosphor formed on the inner wall of the discharge display cell emits light to form a light emitting element of an image display device.

In particular, in the PDP of the present invention, the partition wall has a high dielectric constant of 10 to 30 near the front plate on the discharge electrode side and a low dielectric constant of less than 10 near the rear plate on the address electrode side. It is more preferred to have a ratio.

[0013]

According to the PDP of the present invention, since the partition walls are formed so that at least the dielectric constant of the partition walls is higher in the vicinity of the front plate than in the vicinity of the back plate, the electric field applied between the discharge electrodes in the discharge display cell is reduced. The electric charge is accumulated on the partition wall near the front plate having a high dielectric constant, and does not leak to the adjacent discharge display cells.

Since the amount of charge stored at this time is larger than the amount of charge stored in the partition wall near the back plate having a low dielectric constant, the start voltage of the address discharge is reduced by the partition wall charge. In the discharge electrode that performs continuous sustain discharge, the accumulated charge is assisted, the voltage to be selectively applied can be reduced, and the current for maintaining the discharge can be reduced. As a result, power consumption of the PDP can be reduced.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a PDP according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing a main part of a PDP of the present invention. Reference numeral 1 denotes a partition wall 4 provided in parallel with a space between a back plate 2 and a front plate 3 facing each other, and a discharge partitioned by the partition wall 4. A PDP comprising a display cell 5, a discharge electrode 6 and an address electrode 7 provided in the discharge display cell 5, and a phosphor 8 provided at the bottom of the discharge display cell 5, and at least a dielectric material of a partition 9 near a front plate. The dielectric constant is higher than the dielectric constant of the partition 10 near the back plate.

In the PDP of the present invention, when the dielectric constant of the partition wall is higher in the vicinity of the back plate than in the vicinity of the front plate, the electric field applied between the discharge electrodes in the discharge display cells leaks to the adjacent discharge display cells, causing erroneous discharge. And drive current between the discharge electrode and the address electrode cannot be reduced.

Therefore, the dielectric constant of the partition wall must be higher at least in the vicinity of the front plate on the discharge electrode side than in the vicinity of the rear plate on the address electrode side, so that the electric field does not leak to the adjacent discharge display cells. In particular, from the viewpoint of efficiently generating a plasma discharge required for light emitting display, the dielectric constant of the partition near the front plate is set as high as 10 or more and 30 or less, and the dielectric constant of the partition near the back plate is set as low as less than 10. It is desirable.

Further, the dielectric constant of the partition may be changed continuously from the front plate side to the back plate side or may be changed stepwise. What is necessary is just to comprise so that the dielectric constant of the partition near the front plate at the electrode side may become high.

Next, the PDP of the present invention will be described in detail based on one manufacturing method.

First, a composition for forming a partition wall having a low dielectric constant is applied in a layered form to a predetermined thickness on an insulating substrate serving as a back plate, and then another composition having a higher dielectric constant is applied on the applied layer. Of the partition wall molding composition is layered to a predetermined thickness to form a layer.

Incidentally, three or more layers of the composition for forming a partition wall may be formed such that the higher the dielectric constant, the higher the dielectric constant.

As a method of applying the composition for forming a partition in a layer form, the composition for forming a partition is formed on a back plate having an address electrode formed on its surface in advance in a direction perpendicular to the address electrode by a roll coater method or the like. It can be easily formed by applying by a doctor blade method, a screen printing method, a gravure printing method, or the like, and the doctor blade method is preferable particularly in consideration of mass productivity.

Next, the partition-forming composition layer, which is formed on the back plate by being superimposed on the rear plate, is plastically deformed using a partition-forming mold, and a portion having a high dielectric constant and a portion having a low dielectric constant are formed at upper and lower portions of the partition, respectively. Is continuously formed in close contact with the back plate made of

The partition mold is made of metal or resin.
Any of rubber and the like may be used, and it is also possible to use a composite partition wall mold using a resin or rubber member only on the surface of a metal base material. There is no problem even if a surface treatment or the like is applied to the surface for the purpose of improving the releasability or abrasion resistance.

As the shape of the partition wall forming die, a flat plate-shaped or roll-shaped forming die can be appropriately used as long as unevenness corresponding to the partition shape is formed on the surface thereof.
In particular, in view of the ease of manufacturing the partition wall mold, and the dimensional accuracy and mass productivity of the partition wall molded body, the partition wall forming groove is formed by pressing a roll-shaped mold having a groove formed on the surface thereof while rotating the mold. A mold that plastically deforms the composition for use is optimal.

When the partition is formed, a support such as metal, porcelain, resin, rubber, or the like, which can prevent the back plate from bending, is provided under the back plate to improve the dimensional accuracy of the formed body. More effective in terms.

In the PDP of the present invention, the method of forming the partition walls is not limited to the plastic deformation method, but a sand blast method or the like can be applied.
In this case, it is not necessary to impart plasticity to the composition for forming a partition wall, and various additives may be adjusted so that the composition becomes a tape by drying.

The thus-obtained partition wall molded body is heated to a predetermined temperature together with the back plate, subjected to binder removal treatment, and then fired to be integrated with the back plate. The upper portion has a high dielectric constant, and the lower portion has a low dielectric constant. Can be obtained, and the heat treatment conditions for the binder removal treatment and the baking can be appropriately selected.

Thereafter, each phosphor is applied to a predetermined discharge display cell via a mask pattern and baked. Then, the back plate and the front plate are sealed, and Xe, He-Xe, Ne-Xe is applied.
The discharge display cell is completed by hermetically sealing a discharge gas mainly containing, for example, 10 to 600 Torr.

In the present invention, the material for forming the partition walls becomes vitreous after firing, and any glass material capable of maintaining airtightness may be used. As a composition for forming a partition wall having a high dielectric constant, a dielectric constant of 10 or more is used. Lead-based low-melting glass, etc.
For example, lead borosilicate glass is preferable, and as the composition for forming a partition wall having a low dielectric constant, an alkali-based low-melting glass having a dielectric constant of less than 10 such as an alkali borosilicate glass is preferable.

It is to be noted that a mixture of oxide ceramic powder and the like can be further added as an inorganic component to the partition wall forming composition, and a mixture of the inorganic component and an organic material such as a binder, a solvent, and various additives can be appropriately added. Can be prepared and used according to the molding conditions of the partition walls.

As the organic material suitable for the partition wall forming composition having plastic deformability, the binder may be, for example, a thermoplastic binder such as an acryl-based or butyral-based resin, an ultraviolet curable resin, a photocurable resin, A reaction curable resin such as a curable resin can be used.

As a method of imparting plastic deformability to the layered composition for forming a partition formed on the back plate, the organic substance exhibiting the plastic deformability may be added in advance to the composition for forming a partition. After forming a layered composition for forming a partition wall on the back plate, post-treatments such as drying and gelling may be performed to impart plastic deformability.

On the other hand, as the insulating substrate used for the back plate and the front plate of the present invention, a transparent glass substrate such as soda lime glass, low soda glass, lead alkali silicate glass and borosilicate glass can be used. High strain point low soda glass is preferred.

As the address electrodes on the back plate side,
Silver (Ag), nickel (Ni), aluminum (Al)
Or a conductive metal obtained by mixing a small amount of glass with the conductive metal or an alloy thereof.

A discharge electrode made of a transparent electrode on which indium oxide, tin oxide, or the like is deposited is formed on the front plate, which is an insulating substrate on the display surface side.

Further, by adding various coloring agents to the partition wall forming composition, the dielectric constant of the partition walls is changed, and at the same time, for example, metal oxide is added to the partition wall forming composition on the front plate side. By adding a dark-colored coloring agent made of a material in advance, it becomes possible to impart a function as a black matrix of PDP, thereby enabling the partition walls to be two-colored.

[0039]

Next, the PDP of the present invention was evaluated based on the following example.

First, on a back plate made of soda-lime glass having a thickness of 2 mm and 30 inches in size, an electrode paste containing Ag as a main component and having a width of 50 μm were formed by a thick film printing method.
Were formed in a stripe pattern at a pitch of 220 μm on the entire surface and baked to produce a back plate with address electrodes.

Next, a composition for forming a partition wall having a low dielectric constant comprising an alkali glass-based low-melting glass powder having a dielectric constant of 7 and a butyral resin, a solvent and a dispersant was placed on the back plate with an address electrode. The electrode group is uniformly coated with a doctor blade in the direction perpendicular to the electrode group and applied in layers, and then a lead-based low-melting glass powder having a dielectric constant of 12 and a butyral resin, a solvent, and a dispersant are formed on the coating layer. The composition for forming a partition wall having a dielectric constant was uniformly overlaid with a doctor blade and applied to form a layer.

On the other hand, the width is 40 μm, the height is 200 μm,
A metal roll-shaped partition wall forming die having a large number of partition-shaped concave grooves corresponding to a pitch of 220 μm was prepared.

Thereafter, the back plate with the address electrodes, on which the coating layers of the two types of partition wall forming compositions having different dielectric constants are laminated, is placed on a flat surface of a metal support, and the roll-shaped partition wall forming die is formed. Is pressed and rolled onto the back plate on which the coating layer of the partition wall forming composition is formed and rolled, plastically deforming the layered partition wall forming composition to give a partition shape, and sequentially on the back plate. Then, two types of partition wall molded bodies having different dielectric constants were laminated.

Next, the support was removed, and the backside plate to which the molded partition was adhered was debindered while maintaining the same at a predetermined temperature. Then, the firing atmosphere was appropriately changed according to the main components of each material, and the temperature was 550 to 580 ° C. By firing for 10 minutes, a partition wall for PDP integrated with the back plate with address electrodes was produced.

Thereafter, a phosphor paste was filled between the partition walls by a screen printing method and baked to produce a PDP substrate for evaluation having a phosphor.

A PDP was manufactured on the thus obtained PDP substrate for evaluation by using a front plate on which a transparent discharge electrode made of ITO was formed, and the effects of reducing erroneous discharge and driving current were evaluated.

First, when evaluating the effect of reducing the erroneous discharge, a PDP substrate having barrier ribs formed only with a barrier rib composition having a dielectric constant of 7 was used in the same manner as described above.
DP was prepared.

Various images are displayed on the evaluation PDP thus obtained, and the brightness of the PDP being displayed is measured each time. Since the PDP becomes brighter due to the light emission of the present invention, the effect of reducing the erroneous discharge was evaluated as a reduction ratio of the brightness of the PDP of the present invention with respect to the brightness of the conventional PDP.

[0049]

[Table 1]

As is clear from the table, in the PDP of the present invention, the brightness of any of the images is smaller than that of the conventional PDP, and the erroneous discharge is suppressed and reduced. I understand.

Next, when evaluating the effect of reducing the drive current, as a comparative example, a PDP was prepared in the same manner as described above, using a PDP substrate having a partition formed only with a partition-forming composition having a dielectric constant of 12.

In evaluating the effect of reducing the driving current, each discharge display cell was repeatedly turned on and off continuously, and the power consumption at that time was measured.

As a result, it was confirmed that the power consumption of the comparative PDP was 340 W, whereas the power consumption of the PDP of the present invention was 270 W, which is about 20%, which is a power saving.

[0054]

According to the PDP of the present invention, a plurality of discharge display cells are formed by partitions partitioning a space between a pair of insulating substrates forming a back plate and a front plate, and the dielectric constant of the partitions is at least the address electrode. Since the partition walls are formed so as to be higher in the vicinity of the front plate on the discharge electrode side than in the vicinity of the rear plate on the side, erroneous discharge in which the electric field applied between the discharge electrodes at the start of plasma discharge leaks to the adjacent discharge display cell can be reduced, In addition, power consumption can be reduced by reducing the drive current between the discharge electrode and the address electrode, and a large number of high-definition discharge display cells that provide stable and accurate light-emitting display have been realized. An easy PDP can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a PDP of the present invention.

FIG. 2 is a cross-sectional view showing a main part of a conventional PDP.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 PDP 2 back plate 3 front plate 4 partition wall 5 discharge display cell 6 discharge electrode 7 address electrode 8 phosphor 9 partition wall near front plate 10 partition wall near back plate

Continued on the front page (72) Masahiko Yamamoto, Inventor 1-1, Yamashita-cho, Kokubu-shi, Kagoshima Kyocera Corporation Kagoshima Kokubu Plant (72) Inventor Hiroji Hamada 10-1, Kawai, Gamo-cho, Gamo-gun, Shiga Prefecture (72) Inventor Kiyohiro Sakasegawa 1-4-4 Yamashita-cho, Kokubu-shi, Kagoshima Inside the Kyocera Research Institute

Claims (2)

[Claims] A pair of insulating substrates forming a back plate and a front plate;
A plurality of discharge display cells are constituted by partitions partitioning the space between the insulating substrates, a discharge electrode and an address electrode are provided in the discharge display cell, a discharge gas is hermetically sealed, and a voltage is selectively applied between the electrodes. A plasma display panel, which is applied to generate plasma and emit light from a phosphor formed on the inner wall of a discharge display cell to serve as a light emitting element of an image display device, wherein at least a dielectric constant of a partition near the front plate is close to a rear plate. A plasma display panel characterized by having a higher dielectric constant than the partition walls. 2. The plasma display panel according to claim 1, wherein a dielectric constant of the partition near the front plate is 10 or more and 30 or less, and a dielectric constant of the partition near the back plate is less than 10.