KR20060067427A - Plasma display panel - Google Patents

Abstract

According to the present invention, a plasma display panel is disclosed. The plasma display panel includes an upper substrate; A lower substrate disposed in parallel with the upper substrate; A first partition wall disposed between the upper substrate and the lower substrate and defining discharge cells together with the upper substrate and the lower substrate and formed of a dielectric; Upper discharge electrodes disposed in a first partition wall to surround the discharge cells and extending in one direction; Lower discharge electrodes disposed in a first partition wall to surround the discharge cell, extending in parallel with the upper discharge electrode, and spaced apart from an upper discharge electrode; A short prevention layer interposed between the upper discharge electrodes and the lower discharge electrodes; Address electrodes extending in a direction crossing the upper discharge electrodes and the lower discharge electrodes and disposed on an upper surface of the lower substrate; A lower dielectric layer filling the address electrodes; A phosphor layer disposed in the discharge cell; And a discharge gas in the discharge cell.

Description

Plasma display panel {Plasma display panel}

1 is an exploded perspective view showing a conventional plasma display panel;

2 is an exploded perspective view showing a plasma display panel according to a first embodiment of the present invention;

3 is a cross-sectional view taken along the line III-III of FIG.

4 is a perspective view illustrating an electrode structure of the plasma display panel of FIG. 2;

5 is a vertical cross-sectional view of the plasma display panel according to the second embodiment of the present invention.

<Description of Symbols for Major Parts of Drawings>

111: upper substrate 112: upper discharge electrode

113: lower discharge electrode 114: lower first partition wall

115: protective film 116: upper first partition wall

117, 117 ': short prevention layer 121: lower substrate

122: address electrode 123: lower dielectric layer

124: second partition 125: phosphor layer

130: discharge cell

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel that implements an image by using gas discharge. More particularly, the present invention relates to a plasma display panel, which includes ring type discharge electrodes, and further includes a short prevention layer to prevent a short between discharge electrodes disposed up and down. The present invention relates to a plasma display panel provided.

Recently, a device employing a plasma display panel as a flat panel display device has a large screen and has excellent characteristics of high definition, ultra-thin, light weight, and wide viewing angle, and is easier to manufacture than other flat panel display devices. It is attracting attention as a large flat panel display device.

The plasma display panel is classified into a direct current (DC) type, an alternating current (AC) type, and a hybrid type according to an applied discharge voltage, and classified into a counter discharge type and a surface discharge type according to a discharge structure. Recently, most plasma display panels produced at home and abroad are three-electrode surface discharge plasma display panels.

1 illustrates a conventional three-electrode surface discharge plasma display panel. The illustrated plasma display panel includes an upper substrate 11 and a lower substrate 21 disposed to face the upper substrate 11. Discharge sustaining electrode pairs 16 are disposed on the lower surface of the upper substrate 11, and the upper dielectric layer 14 and the protective film 15 covering the upper dielectric layer 14 are embedded in this order. Here, one electrode of the discharge sustaining electrode pair 16 is the scan electrode 12, the other electrode is the common electrode 13, and the scan electrode 12 and the common electrode 13 are transparent electrodes 12a and 13a, respectively. ) And bus electrodes 12b and 13b.

On the other hand, an upper surface of the lower substrate 21 is formed with an address electrode 22 extending to intersect with the discharge sustaining electrode pair 16 and a lower dielectric layer 23 embedded therein. A partition wall 24 is formed on the lower dielectric layer 23 to partition the plurality of discharge cells. The phosphor layer 25 is disposed on the lower dielectric layer 23 over the partition wall 24, and the space inside the discharge cell is filled with discharge gas.

In such a plasma display panel, plasma is formed by discharge performed by the discharge sustaining electrode pair 16, and the phosphor layer 25 is excited by vacuum ultraviolet rays emitted from the formed plasma to emit visible light, thereby realizing an image. do.

However, in the conventional three-electrode surface discharge structure shown, the discharge sustain electrode pair is formed on the lower side of the upper substrate, so that the discharge sustain electrode has to use a transparent material to transmit visible light upward. While passing through the discharge sustaining electrode pair 16, the upper dielectric layer 14, and the protective film 15 formed on the lower side of the upper substrate 11, there was a problem that visible light was absorbed by these structures and the luminous efficiency was very low.

In addition, since the discharge electrodes causing the sustain discharge are arranged horizontally with each other, there is a problem that the discharge efficiency is low because the discharge space is not used efficiently.

In order to solve the above problems and other problems, an object of the present invention is to provide a plasma display panel that can secure a wide space for sustain discharge by using the discharge space efficiently.                         

Another object of the present invention is to provide an improved plasma display panel which can prevent the discharge electrodes from being shorted by their own weight in arranging ring-type discharge electrodes up and down to surround the discharge space.

In order to achieve the above objects and other objects, the plasma display panel of the present invention,

Upper substrate;

A lower substrate disposed in parallel with the upper substrate;

A first partition wall disposed between the upper substrate and the lower substrate and defining discharge cells together with the upper substrate and the lower substrate and formed of a dielectric;

Upper discharge electrodes disposed in a first partition wall to surround the discharge cells and extending in one direction;

Lower discharge electrodes disposed in a first partition wall to surround the discharge cell, extending in parallel with the upper discharge electrode, and spaced apart from an upper discharge electrode;

A short prevention layer interposed between the upper discharge electrodes and the lower discharge electrodes;

Address electrodes extending in a direction crossing the upper discharge electrodes and the lower discharge electrodes and disposed on an upper surface of the lower substrate;

A lower dielectric layer filling the address electrodes;

A phosphor layer disposed in the discharge cell; And

And a discharge gas in the discharge cell.                     

Here, the anti-short layer is made of a non-conductive material.

Preferably, the anti-short layer is a black nonconductive material.

In particular, the short prevention layer preferably includes any one component selected from the group consisting of cobalt, manganese and molybdenum.

In addition, the short prevention layer is preferably attached to the lower discharge electrode.

On the other hand, the width of the short prevention layer is preferably the same as the width of the lower discharge electrode,

Optionally, the width of the short prevention layer may be equal to the width of the first partition wall.

On the other hand, it is preferable to further include a second partition wall defining a discharge cell together with the first partition wall, wherein the phosphor layer is disposed on the same level as the second partition wall.

In addition, the upper discharge electrodes and the lower discharge electrodes have a ladder shape extending in one direction, and at least a side surface of the first partition wall is covered by a protective film.

Next, the plasma display panel according to the first embodiment of the present invention will be described in detail with reference to FIGS. 2 to 4. 2 is an exploded perspective view showing a plasma display panel according to a first embodiment of the present invention, Figure 3 is a cross-sectional view taken along the line III-III of Figure 2, Figure 4 is a perspective view showing the electrode structure of the first embodiment to be.

Referring to FIG. 2, the plasma display panel according to the present exemplary embodiment includes an upper substrate 111 and a lower substrate 121 disposed on a lower side thereof (as opposed to z). The upper substrate 111 and the lower substrate 121 are typically formed of a material mainly containing glass. In particular, when the upper substrate 111 is used as the image display surface, it is preferable that the upper substrate 111 is formed of a transparent substrate having excellent light transmittance. The upper substrate 111 and the lower substrate 121 define the discharge cells 130 in the up and down direction, wherein the discharge cells 130 are formed of a red subpixel, a green subpixel, and a blue subpixel constituting one pixel. It means one subpixel. The discharge cell 130 is defined in the up and down direction by the upper substrate 111 and the lower substrate 121, so that one discharge cell 130 of FIG. 3 is in the up and down direction from the lower surface of the upper substrate 111. It means to include the area up to the upper surface of (121), and more specifically, it includes the address electrode 122, the dielectric layer 123, the discharge space formed in the panel, the phosphor layer 125 do.

As shown in FIG. 2, a first partition wall is formed below the upper substrate 111, and the first partition wall includes an upper first partition wall 116 and a lower first partition wall 114. 114 and 116 define side surfaces of the discharge cells 130 to prevent erroneous discharges between the discharge cells 130. The first partition walls 114 and 116 illustrated in FIG. 4 may extend in the x and y directions to form a matrix. The first partition walls 114 and 116 of the present invention are not limited to such a matrix shape, but may be an open partition such as a stripe or the like and a closed partition such as a waffle or a delta. The first barrier ribs 114 and 116 formed of the dielectric material prevent the upper discharge electrode 112 and the lower discharge electrode 113 from being directly energized during discharge and induce accumulation of wall charges. Dielectrics forming the first partitions 114 and 116 include PbO, B 2 O 3, SiO 2, and the like.

Referring to FIG. 2, the side surfaces of the first barrier ribs 114 and 116 are preferably covered by the passivation layer 115. The passivation layer 115 has charged particles formed by the discharge on the first barrier ribs 114 and 116. It prevents from being damaged by collision and emits a lot of secondary electrons. The protective film 115 may typically be formed of an MgO film.

The upper discharge electrode 112 and the lower discharge electrode 113 are embedded in the first partition walls 114 and 116. The upper discharge electrode 112 and the lower discharge electrode 113 are disposed to be spaced apart from each other in the vertical direction. The sustain discharge is performed by these discharge electrodes 112 and 113 to realize an image.

Referring to FIG. 4, the upper discharge electrode 112 and the lower discharge electrode 113 are disposed in parallel to each other, and are formed in a ladder shape and surround the four side surfaces of the discharge cell 130 and extend in the x direction. One of the discharge electrodes 112 and 113 serves as a scan electrode, and the other electrode serves as a common electrode. When the scan electrode is disposed adjacent to the address electrode 122, the address voltage can be lowered. Therefore, in this embodiment, the lower discharge electrode 113 adjacent to the address electrode 122 acts as the scan electrode. The upper discharge electrode 112 and the lower discharge electrode 113 are formed of a metal material having excellent electrical conductivity, for example, Ag, Cu, Al, or the like.

In the conventional plasma display panel, the discharge sustaining electrode pair is formed below the upper substrate, and the discharge sustaining electrode pair includes a transparent electrode such as ITO for the upward transmission of visible light. In the present invention, since the discharge electrodes 112 and 113 are disposed in the first partition walls 114 and 116, the discharge electrodes 112 and 113 may be formed of metal electrodes having excellent electrical conductivity. Therefore, the voltage drop caused by the electrode itself is minimized, driving efficiency and response speed are improved, and a uniform voltage can be applied to the discharge cells disposed at a relatively long distance from the point of application of the voltage.

Meanwhile, referring to FIG. 2, an address electrode 122 is disposed on an upper side of the lower substrate 121, for example, an upper surface of the lower substrate 121. The address electrodes 122 may be formed in a stripe pattern along the discharge cells 130 in one row (y direction). As shown in FIG. 4, the address electrodes 122 intersect with the extension directions (x directions) of the discharge electrodes 112 and 113. It extends in the direction (y direction). The address electrode 122 may be formed of a metal material having excellent electrical conductivity, for example, a metal electrode such as Ag, Cu, Al, or the like.

The address electrode 122 is used to generate an address discharge for facilitating sustain discharge between the upper discharge electrode 112 and the lower discharge electrode 113. More specifically, the address electrode 122 serves to lower the voltage at which the sustain discharge starts. . The address discharge is a discharge occurring between the scan electrode and the address electrode 122. When the address discharge is completed, cations accumulate on the scan electrode side and electrons accumulate on the common electrode side, thereby making it easier to sustain discharge between the scan electrode and the common electrode. Done.

As shown in FIG. 2, the address electrodes 122 are buried by the lower dielectric layer 123. In the lower dielectric layer 123, charged particles of the discharge gas collide directly with the address electrode 122 so that the address electrode 122 is disposed. It prevents damage to, and induces wall charge. Examples of the dielectric for forming the lower dielectric layer 123 include PbO, B 2 O 3, and SiO 2.

As shown in FIG. 3, the upper discharge electrode 112 is buried by the upper first partition 116, and the lower discharge electrode 113 is buried by the lower first partition 114. The reason why the first partition is divided into the upper first partition 116 and the lower first partition 114 is that the upper discharge electrode 112 and the upper first partition 116 are formed in the step of forming the discharge electrode and the first partition. Since the lower discharge electrode 113 and the lower first partition 114 are sequentially formed, the upper first partition 116 and the lower first partition 114 are formed to be distinguished with a time difference in the manufacturing process. to be.

Although the first partition wall is formed by being divided into the upper first partition 116 and the lower first partition 114, since the upper first partition 116 and the lower first partition 114 are formed of the same material, it is final. As a result, the upper first partition 116 and the lower first partition 114 integrally form one first partition.

Referring to the steps of forming the first partition and the discharge electrode in more detail, since the upper substrate 111 shown in Figure 3 is formed separately from the lower substrate 121 in the actual manufacturing process, the upper substrate 111 When the first barrier rib and the discharge electrode are formed on the substrate, the structure of the upper substrate lower portion shown in FIG. 3 is inverted upside down. That is, although the first barrier rib and the discharge electrode are formed on the lower side of the upper substrate 111 in FIG. 3, in the manufacturing process of forming the first barrier rib and the discharge electrode on the upper substrate, 1 After forming the partition and the discharge electrode, the completed structure is reversed and assembled with the structure of the lower substrate.                     

Therefore, in the step of explaining the manufacturing process, the lower direction in FIG. 3 is described as the upper side.

The upper discharge electrode 112 is formed on the upper surface of the front substrate 111 through printing, exposure, development, and firing steps. In the first embodiment, the upper discharge electrode 112 is formed to be spaced apart from the upper surface of the front substrate, but is not necessarily limited thereto, and the upper discharge electrode 112 may be formed in contact with the upper substrate 111. It may be.

Next, a dielectric layer is formed through the printing, exposure, development, and firing steps to fill the upper discharge electrode 112 to form the upper first partition wall 116. After the upper first partition 116 is formed, a non-conductive short-circuit prevention layer 117 is formed on the upper surface of the upper first partition 116.

The short prevention layer 117 is preferably a non-conductive black stripe material, more specifically, it is preferable to include cobalt, manganese, molybdenum and the like. After the short prevention layer 117 is formed, the lower discharge electrode 113 is formed on the upper surface through printing, exposure, development and firing processes, and the dielectric is printed and exposed to fill the lower discharge electrode 113 again. , The shape and the firing are to form the lower first partition wall 114.

Here, the short prevention layer 117 is at least in contact with the lower discharge electrode 113, the width of the short prevention layer 117 is preferably equal to or larger than the width of the lower discharge electrode 113.

Therefore, after performing the process of forming the first partition and the discharge electrode as described above, as shown in Figure 3 when the assembly of the lower substrate and the upper substrate, the process step of forming the discharge electrode and the first partition Even if the lower first partition wall 114 is lowered by gravity and the thickness of the upper first partition wall 116 between the upper discharge electrode 112 and the lower discharge electrode 113 decreases, the non-conductive short between the discharge electrodes is reduced. Since the prevention layer 117 is formed, both discharge electrodes are not shorted.

2 and 3, a second partition wall 124 is formed on the lower dielectric layer 123 on the lower substrate 121. The second partition 124 together with the first partition 114 defines a side surface of the discharge cell 130. In the embodiment of Figure 2, it is formed in a matrix shape extending in the x direction and the y direction. The second partition wall 124 of the present invention can be formed in a variety of structures other than such a matrix shape, for example, as well as an open partition structure of a stripe pattern, formed of a closed partition structure such as waffle, delta type. May be

The phosphor layer 125 is formed at the same level as the second barrier 124, which means that the phosphor layer 125 is disposed at the same height as the second barrier 124. More specifically, in the present exemplary embodiment, the phosphor layer 125 is disposed on the side of the second partition wall 124 on the dielectric layer 123 on the lower substrate 121 surrounded by the second partition wall 124. The phosphor layer 125 receives vacuum ultraviolet rays emitted from the plasma generated by the discharge and converts the visible rays into visible light.

Each of the discharge cells 130 is divided into a red light emitting subpixel, a green light emitting subpixel, and a blue light emitting subpixel according to the type of the phosphor layer 125 disposed. The phosphor layer formed on the red light emitting subpixel may include phosphors such as Y (V, P) O4: Eu, and the phosphor layer 25 formed on the green light emitting subpixels may include phosphors such as Zn2SiO4: Mn, YBO3: Tb, and the like. The phosphor layer 25 formed in the blue light emitting subpixel may include phosphors such as BAM: Eu and the like.

The discharge cells 130 are filled with discharge gases such as Ne, Xe, and the like and mixed gases thereof. In the case of the present invention including this embodiment, the discharge surface can be increased and the discharge region can be enlarged, so that the amount of plasma formed is increased, thereby enabling low voltage driving. Therefore, in the case of the present invention, even when a high concentration of Xe gas is used as the discharge gas, low voltage driving is possible, thereby significantly improving the luminous efficiency. This solves the problem of low voltage driving when using a high concentration of Xe gas as a discharge gas in a conventional plasma display panel.

Referring to FIG. 3, in the plasma display panel according to the first exemplary embodiment of the present invention, the address discharge is caused by applying an address voltage between the address electrode 122 and the lower discharge electrode 113. As a result of this address discharge, the discharge cells 130 in which sustain discharge is to be generated are selected.

Thereafter, when a sustain discharge voltage of AC is applied between the upper discharge electrode 112 and the lower discharge electrode 113 of the selected discharge cell 130, the sustain discharge is discharged between the upper discharge electrode 112 and the lower discharge electrode 113. This happens. Ultraviolet rays are emitted while the energy level of the discharged gas excited by this sustain discharge is lowered. The ultraviolet rays excite the phosphor layer 125 coated in the discharge cell 130. As the energy level of the excited phosphor layer 125 decreases, visible light is emitted, and the emitted visible light forms an image. .                     

In the conventional plasma display panel shown in Fig. 1, the sustain discharge between the scan electrode 12 and the common electrode 13 occurs in the horizontal direction, so that the discharge area is relatively narrow. However, since the sustain discharge of the plasma display panel according to the present embodiment occurs in the vertical direction in all aspects defining the discharge cell 130, there is an advantage that the discharge area is relatively large.

In addition, the sustain discharge in this embodiment is formed in a closed curve along the side of the discharge cell 130 and gradually diffuses to the center portion of the discharge cell (130). As a result, the volume of the region in which the sustain discharge occurs is increased, and the space charge in the discharge cell 130 which is not well used in the past also contributes to light emission. Such matters result in the improvement of the luminous efficiency of the plasma display panel.

In addition, in the plasma display panel according to the present embodiment, as shown in FIG. 3, since the sustain discharge is performed only at the portion defined by the first partition wall 114, the phosphor layer by the charged particles, which has been a problem of the conventional plasma display panel. Ion sputtering of 125 is prevented, and thus there is an advantage that a permanent afterimage does not occur even if the same image is displayed for a long time.

5 is a diagram illustrating a plasma display panel according to a second embodiment of the present invention, in which the same components as those in the first embodiment shown in FIGS. The other configurations are the same except for the width of the short prevention layer interposed between the electrode 112 and the lower discharge electrode 113. Hereinafter, a description will be given focusing on differences from the first embodiment.                     

As shown in FIG. 5, the upper discharge electrode 112 is buried by the upper first partition 116, and the lower discharge electrode 113 is buried by the lower first partition 114. The reason why the first partition is divided into the upper first partition 116 and the lower first partition 114 is that the upper discharge electrode 112 and the upper first partition 116 are formed in the step of forming the discharge electrode and the first partition. ), The lower discharge electrode 113 and the lower first partition wall 114 are sequentially formed, thereby distinguishing the upper first partition wall 116 and the lower first partition wall 114 with a time difference in the manufacturing process. Because.

Although the first partition wall is formed by being divided into the upper first partition 116 and the lower first partition 114, since the upper first partition 116 and the lower first partition 114 are formed of the same material, it is final. As a result, the upper first partition wall 116 and the lower first partition wall 114 form a first partition wall.

Referring to the step of forming the first partition and the discharge electrode in more detail, since the upper substrate 111 shown in Figure 5 is formed separately from the lower substrate 121, the first substrate on the upper substrate 111 When the barrier rib and the discharge electrode are formed, the structure of the lower side of the upper substrate shown in FIG. 5 is manufactured upside down. That is, although the first barrier rib and the discharge electrode are formed on the lower side of the upper substrate 111 in FIG. 5, in the step of forming the first barrier rib and the discharge electrode on the upper substrate, the first barrier is formed on the upper side of the upper substrate. The barrier ribs and the discharge electrodes are formed to invert the complete structure and to be assembled with the structure of the lower substrate.

Therefore, in the step of explaining the manufacturing process, the lower direction in FIG. 5 is described as the upper side.                     

First, the discharge electrode 112 is formed on the upper surface of the front substrate 111 through printing, exposure, development, and firing steps. In the second embodiment of the present invention, the upper discharge electrode 112 is formed spaced apart from the upper surface of the front substrate, but is not necessarily limited thereto, the upper discharge electrode 112 is in contact with the upper substrate 111 It may be formed.

Next, a dielectric layer is formed through the printing, exposure, development, and firing steps to fill the upper discharge electrode 112 to form the upper first partition wall 116. After the first partition 116 is formed, a non-conductive short prevention layer 117 'is formed on the upper surface of the upper first partition wall.

After the short prevention layer 117 'is formed, the lower discharge electrode 113 is formed on the upper surface through printing, exposure, development, and firing processes, and the dielectric is printed to fill the lower discharge electrode 113 again. The lower first partition wall 114 is formed by exposure, development, and firing.

Here, the short prevention layer 117 'is disposed at least in contact with the lower discharge electrode 113, and the width of the short prevention layer 117' is preferably equal to the width of the first partition wall, unlike the first embodiment. As the width of the short prevention layer 117 'is widened, the contrast of the plasma display panel of the second embodiment can be improved.

Therefore, after performing the process of forming the first partition and the discharge electrode as described above, as shown in Figure 5, assembling the structure of the lower substrate and the upper substrate, as in the case of the first embodiment described above, the discharge In the fixing step of forming the electrode and the first partition wall, the lower first partition wall 114 is lowered by gravity to reduce the thickness of the upper first partition wall 116 between the upper discharge electrode 112 and the lower discharge electrode 113. Even if the non-conductive short prevention layer 117 'is formed between the discharge electrodes, both of the discharge electrodes are not shorted.

In addition, the matters relating to the lower substrate 121, the address electrode 122, the protective film 215, and the phosphor layer 225 are substantially the same as those of the first embodiment.

Meanwhile, in the drawings attached to the present specification, partition walls defining side surfaces of the discharge cells are illustrated to be separated up and down, but the present invention is not limited thereto, and the partition walls may be applied to a case where the partition walls are integrally formed. .

According to the plasma display panel according to the present invention, the following effects can be obtained.

First, since the discharge electrodes causing the sustain discharge are not disposed horizontally but are disposed vertically with each other, the effective discharge area in which the sustain discharge occurs is widened, so that the discharge efficiency is excellent.

Second, since the short prevention layer is interposed between the upper discharge electrode and the lower discharge electrode disposed in the upper and lower relations with each other, the short generation between the discharge electrodes due to the weight of the discharge electrode at the time of forming the discharge electrode of the front substrate can be fundamentally prevented. There is this.

Third, since the black short prevention layer is formed between the discharge electrodes positioned up and down, there is an advantage that the contrast of the image is improved.

Although the present invention has been described with reference to the embodiments shown in the 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. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (9)

Upper substrate; A lower substrate disposed in parallel with the upper substrate; A first partition wall disposed between the upper substrate and the lower substrate and defining discharge cells together with the upper substrate and the lower substrate and formed of a dielectric; Upper discharge electrodes disposed in a first partition wall to surround the discharge cells and extending in one direction; Lower discharge electrodes disposed in a first partition wall to surround the discharge cell, extending in parallel with the upper discharge electrode, and spaced apart from an upper discharge electrode; A short prevention layer interposed between the upper discharge electrodes and the lower discharge electrodes; Address electrodes extending in a direction crossing the upper discharge electrodes and the lower discharge electrodes and disposed on an upper surface of the lower substrate; A lower dielectric layer filling the address electrodes; A phosphor layer disposed in the discharge cell; And And a discharge gas in the discharge cell. The method of claim 1, And the short prevention layer is made of a non-conductive material. The method of claim 2, And the short prevention layer is a black non-conductive material. The method of claim 2, And the short prevention layer comprises any one component selected from the group consisting of cobalt, manganese and molybdenum. The plasma display panel of claim 1, wherein the short prevention layer is attached to the lower discharge electrode. The method of claim 1, And a width of the short prevention layer is equal to a width of the lower discharge electrode. The method of claim 1, The width of the short prevention layer is the same as the width of the first partition wall plasma display panel. The method according to any one of claims 1 to 7, And a second partition wall defining a discharge cell together with the first partition wall. And the phosphor layer is disposed at the same level as the second partition wall. The method according to any one of claims 1 to 7, The upper discharge electrodes and the lower discharge electrodes have a ladder shape extending in one direction, And at least a side surface of the first partition wall is covered by a protective film.

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