KR20060019813A - Plasma display panel - Google Patents

Abstract

A plasma display panel according to the present invention comprises: an upper substrate; A lower substrate disposed to face the upper substrate; Discharge cells formed between the upper substrate and the lower substrate to perform discharge; By providing a protective film disposed corresponding to the discharge cells and having a surface roughness of 300 nm to 800 nm, long life and display quality can be stabilized.

Description

Plasma display panel {Plasma display panel}

1 is an exploded perspective view of a plasma display panel according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1. FIG.

3 is a graph showing the refractive index and the address delay time according to the surface roughness of the MgO film.

 <Brief description of the major symbols in the drawings>

111.Top substrate 112.Top dielectric layer

113..MgO membrane 121..holding electrode pair

122. Common electrode 125. Scanned electrode

131 Lower substrate 132. Address electrode

133. Lower dielectric layer 134 Bulkhead

135. Discharge cell 136. Phosphor layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to a plasma display panel having an improved structure to achieve long life and stable display quality.

Recently, the plasma display panel, which is attracting attention as a substitute for the cathode ray tube, is discharged after a discharge gas is filled between two substrates on which a plurality of electrodes are formed, and a discharge voltage is applied in a predetermined pattern by ultraviolet rays generated thereby. The formed phosphor layer is excited to display an image.

Such plasma display panels are classified into DC type and AC type according to the driving method. In a DC plasma display panel, the electrodes are exposed to a discharge space to directly transfer charges between corresponding electrodes. In an AC plasma display panel, at least one electrode is covered with a dielectric layer and wall charges accumulated in the dielectric layer Discharge is caused by the movement of the wall charge.

In the DC plasma display panel, since the charge is directly transferred between the corresponding electrodes, there is a problem that the electrodes are severely damaged. In recent years, an AC plasma display panel having a three-electrode surface discharge structure has been adopted. There is a trend.

A typical AC plasma display panel includes an upper substrate on which an image is displayed and a lower substrate disposed so as to face in parallel with the upper substrate. On the lower surface of the upper substrate, sustain electrode pairs including a common electrode and a scan electrode are formed, and the sustain electrode pairs are embedded by an upper dielectric layer. In addition, address electrodes are formed on the upper surface of the lower substrate so as to intersect with the sustain electrode pairs, and the address electrodes are filled by the lower dielectric layer. A partition wall is formed on an upper surface of the lower dielectric layer to define discharge cells. The discharge cells are filled with a discharge gas, and the red, green, and blue phosphor layers are selectively formed to implement a color.

In the plasma display panel configured as described above, the upper dielectric layer may be covered by the MgO film, which protects the upper dielectric layer from being damaged by ion sputtering and discharges secondary electrons when discharged. do. When a large amount of secondary electrons are emitted from the MgO film, discharge may be facilitated, and thus a sustain voltage applied between the common electrode and the scan electrode may be lowered, and thus power consumption may be reduced.

The MgO film may be formed on the upper dielectric layer by vapor deposition. When the density of the deposited MgO film is increased, the longevity of the MgO film may be directed. In this case, it takes a lot of time, and it is difficult to induce sufficient activation by the conventional method, which causes a problem of deterioration of display quality.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a plasma display panel which can achieve long life and stabilization of display quality by setting the surface roughness of the protective film in an appropriate range.

Plasma display panel according to the present invention for achieving the above object,

An upper substrate;

A lower substrate disposed to face the upper substrate;

Discharge cells formed between the upper substrate and the lower substrate to perform discharge;

And a protective film disposed corresponding to the discharge cells and having a surface roughness of 300 nm to 800 nm.

Here, it is preferable that the surface roughness of the said protective film is 400 nm-550 nm.

Here, the protective film is preferably formed of MgO.

And, the plasma display panel according to the present invention,

An upper substrate;

A plurality of sustain electrode pairs formed under the upper substrate;

An upper dielectric layer filling the sustain electrode pairs;

A lower substrate disposed to face the upper substrate;

Address electrodes formed on the lower substrate so as to cross the sustain electrode pairs;

A lower dielectric layer filling the address electrodes;

Barrier ribs formed between the upper substrate and the lower substrate and defined by discharge cells in which the sustain electrode pairs and the address electrodes are disposed to correspond to each other;

A phosphor layer disposed on the discharge cells;

Discharge gas filled in the discharge cells;

And a protective film formed on a lower surface of the upper dielectric layer and having a surface roughness of 300 nm to 800 nm.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view of a plasma display panel according to an exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1.

1 and 2, the plasma display panel 100 is provided with an upper substrate 111 and a lower substrate 131 disposed to face the upper substrate 111. A plurality of storage electrode pairs 121 are arranged on a surface of the upper substrate 111 facing the lower substrate 131, and the storage electrode pairs 121 are covered by the upper dielectric layer 112. An MgO film 113 is formed on the bottom surface of the upper dielectric layer 112 as a protective film according to an aspect of the present invention, which will be described later.

The storage electrode pairs 121 are formed by using a pair of the common electrode 122 and the scan electrode 125 that form a discharge gap G therebetween. As illustrated, the common electrode 122 includes a common transparent electrode 123 and a common bus electrode 124 connected thereto, and the scan electrode 125 is connected to the scan transparent electrode 126 and a scan connected thereto. The bus electrode 127 may be provided.

The common and scan transparent electrodes 123 and 126 are made of indium tin oxide (ITO), which is a transparent material in order to transmit visible light emitted from the phosphor layer 136. The common and scan bus electrodes 124 and 127 connected to the common and scan transparent electrodes 123 and 126, respectively, serve to apply voltages to the common and scan transparent electrodes 123 and 126, respectively. In order to improve the electrical resistance of the common and scan transparent electrodes 123 and 126 formed of ITO having relatively low electrical conductivity, it is preferably formed of a metal having excellent conductivity.

The common and scan bus electrodes 124 and 127 have a width smaller than that of the common and scan transparent electrodes 123 and 126 and extend in a direction parallel to the direction in which the horizontal partition walls 134b are formed. The common transparent electrode 123 is formed of a plurality of divided common protrusion electrodes 123a, and the common bus electrodes 124 are spaced apart from each other with the vertical protrusions 134a interposed therebetween. And the scan transparent electrode 126 is composed of a plurality of scan protrusion electrodes 126a, and the scan protrusion electrodes 126a are spaced apart from each other with the vertical partition wall 134a interposed therebetween. It is connected to the low scan bus electrode 127. The common protrusion electrode 123a and the scan protrusion electrode 126a are disposed to form a discharge gap G between the discharge cells 135. As the common and scan transparent electrodes 123 and 126 have a structure in which portions corresponding to the vertical partitions 134a are deleted, the discharge areas of the common and scan transparent electrodes 123 and 126 are reduced. It can be reduced, and current can be limited to reduce power consumption. On the other hand, the structure of the storage electrode pair is not limited to the above-mentioned, and may be formed in various shapes.

In the lower substrate 131 facing the upper substrate 111, address electrodes 132 are arranged to intersect the storage electrode pairs 121 on a surface facing the upper substrate 111. The address electrodes 132 are covered by a lower dielectric layer 133, and a partition 134 is formed on an upper surface of the lower dielectric layer 133.

The partition wall 134 is limited to the plurality of discharge cells 135 and prevents cross talk with adjacent discharge cells 135. The barrier ribs 134 may include vertical barrier ribs 134a formed to be spaced apart at predetermined intervals, and horizontal barrier ribs 134b extending from the side surfaces of the vertical barrier ribs 134a in a direction crossing the vertical barrier ribs 134a. It can be configured to include. Here, the vertical partitions 134a are disposed in parallel with one address electrode 132 interposed therebetween. As the vertical bulkheads 134a and the horizontal bulkheads 134b are formed as described above, they may be limited to the discharge cells 135 closed in four surfaces in a matrix form. On the other hand, the partition wall is not limited to the above, any structure can be used as long as it can limit the discharge cells to the pixel array pattern.

Phosphor is coated on the inner surface of the partition 134 and the upper surface of the lower dielectric layer 133 surrounded by the partition 134 to form the phosphor layer 136. The color of the phosphor is composed of red, green, and blue to implement a color screen, and forms a phosphor layer of red, green, and blue according to the color of the phosphor.

According to the color of the phosphor layer 136, the discharge cells 135 are roughly divided into red, green, and blue discharge cells, and three adjacent red, green, and blue discharge cells are formed in unit pixels. Will be configured. The discharge cells 135 are filled with a discharge gas, and in the state where the discharge gas is filled, the upper substrate (not shown) is formed by a sealing member (not shown) formed at the edge of the upper substrate 111 and the lower substrate 131. 111 and the lower substrate 131 are sealed to each other.

Referring to the operation of the plasma display panel 100 configured as described above is as follows. First, when an address voltage is applied between the scan electrode 125 and the address electrode 132, an address discharge occurs, and as a result of the address discharge, a discharge cell 135 in which sustain discharge occurs is selected. After the address discharge is executed, if a sustain voltage is alternately applied between the common electrode 122 and the scan electrode 125 disposed in the selected discharge cell 135, the common electrode 122 and the scan electrode 125 are applied. Sustain discharge occurs. Ultraviolet rays are emitted while the energy level to the discharge gas excited by such sustain discharge is lowered. Such ultraviolet rays excite the phosphor layer 136 formed in the discharge cell 135, and the visible light is emitted from the excited phosphor layer 136 to realize an image.

On the other hand, the protective film according to an aspect of the present invention formed to cover the lower surface of the upper dielectric layer 112, for example, MgO film that can prevent the damage to the upper dielectric layer 112 and emit secondary electrons by ion sputtering It may be formed of (113). As described above, when a large amount of secondary electrons are emitted from the MgO film 113, the discharge becomes easy, and thus a sustain voltage applied between the common electrode 122 and the scan electrode 125 may be lowered. This can be reduced.

The MgO film 113 may be formed on the bottom surface of the upper dielectric layer 112 by various methods. For example, a physical vapor deposition method may be used. According to the above physical vapor deposition method, the MgO particles sublimed and scattered by high heat are cooled and crystallized on the lower surface of the upper dielectric layer 112, and the MgO film 113 is formed as the crystallized MgO crystals grow. .

As described above, the MgO film 113 deposited on the lower surface of the upper dielectric layer 112 by the physical vapor deposition method has a predetermined density. However, when the density of the MgO film 113 is increased, it is possible to achieve long life. When too high, it takes a long time for the aging for the activation of the MgO film 113, the activation may be difficult to be sufficiently induced. As a result, deterioration of display quality is caused, so that the density of the MgO film 113 needs to be set within a predetermined range.

The density of the MgO film 113 is known to have a close correlation with the surface roughness of the MgO film 113. When the value of the surface roughness of the MgO film 113 is set in an appropriate range, the longevity is long. It will be possible to obtain an MgO film 113 having a density sufficient to stabilize the brightening and display quality. The optimum range of the surface roughness of the MgO film 113 may be set by the experimental data of the graph shown in FIG. 3.

3 is a graph showing the refractive index and the address delay time according to the surface roughness of the MgO film. Here, the refractive index is an index indicating the density of the MgO film, and the address delay time is an index indicating discharge stability, that is, display quality. In addition, the measured value of the refractive index is a value measured at 650 nm wavelength of visible light among the values measured over the entire wavelength region of visible light.

According to the graph, as the surface roughness of the MgO film 113 increases, the refractive index tends to decrease, and the address delay time tends to be short. The decrease in the refractive index means that the density of the MgO film 113 is lowered. Therefore, as the surface roughness of the MgO film 113 increases, the density of the MgO film 113 decreases. The shorter this means that the higher the discharge stability, the higher the surface roughness of the MgO film 113, the higher the discharge stability. On the contrary, as the surface roughness of the MgO film 113 decreases, the density of the MgO film 113 increases, but the discharge stability decreases.

Based on the data having such a tendency, the surface roughness of the MgO film 113 which can satisfy both the density and the discharge stability of the MgO film 113 to a certain level or more can be set to approximately 300 nm to 800 nm. It may be, and more preferably may be set to 400nm to 550nm.

According to the present invention as described above, by setting the surface roughness of the protective film to an appropriate range, long life can be directed. In addition, activation is sufficiently induced, and the discharge stability can be secured, so that the display quality can be stabilized.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Could be. Accordingly, the true scope of protection of the invention should be defined only by the appended claims.

Claims (6)

An upper substrate; A lower substrate disposed to face the upper substrate; Discharge cells formed between the upper substrate and the lower substrate to perform discharge; And a protective film disposed corresponding to the discharge cells and having a surface roughness of 300 nm to 800 nm. The method of claim 1, The surface roughness of the protective film is a plasma display panel, characterized in that 400nm to 550nm. The method according to claim 1 or 2, The protective film is plasma display panel, characterized in that formed of MgO. The method of claim 3, wherein The protective film is plasma display panel, characterized in that formed by physical vapor deposition. An upper substrate; A plurality of sustain electrode pairs formed under the upper substrate; An upper dielectric layer filling the sustain electrode pairs; A lower substrate disposed to face the upper substrate; Address electrodes formed on the lower substrate so as to cross the sustain electrode pairs; A lower dielectric layer filling the address electrodes; Barrier ribs formed between the upper substrate and the lower substrate and defined by discharge cells in which the sustain electrode pairs and the address electrodes are disposed to correspond to each other; A phosphor layer disposed on the discharge cells; Discharge gas filled in the discharge cells; And a protective film formed on a lower surface of the upper dielectric layer and having a surface roughness of 300 nm to 800 nm. The method of claim 5, The surface roughness of the protective film is a plasma display panel, characterized in that 400nm to 550nm.

Images