JPH0644910A - Plasma display panel - Google Patents

Abstract

PURPOSE:To avoid the occurrence of locally concentrated discharge by composing a cathode within one cell of a low resistance part having a specific value and a high resistance part and making the area of the high resistance part larger than that of the low resistance part. CONSTITUTION:A cathode 3 within one cell is composed of two parts including a low resistance part and a high resistance part and the area of the high resistance part is made larger than that of the resistance part. The sheet resistor of the low resistance part is formed to be not more than 10OMEGA and that of the high resistance part is formed to be above 10kOMEGA, and both parts are shaped in continuous form. And when a discharge current is increased, glow discharge is initiated in the low resistance part at first and sequentially the discharge is expanded into the high resistance part. When the discharge current reaches a current value which is determined by a voltage applied to a tube, the expansion of discharge is not more than the area of the low resistance part, and when cathode materials have a high gamma value, the discharge is locally concentrated, so that the runaway of current occurs even in the case where they are driven by the same voltage. Therefore, the area of the high resistance part is made larger than that of the low resistance part, thereby making it feasible to avoid the local concentration of discharge even when the gamma value of the cathode materials is high or the pressure of discharge gas is high.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct current type plasma display panel, and more particularly to a plasma display panel in which a cathode has a low resistance portion and a high resistance portion, which are continuously formed.

[0002]

2. Description of the Related Art There are two types of direct current plasma display panels (hereinafter simply referred to as "PDPs") for observing the emission color of a discharge gas and for causing a phosphor to emit visible light by ultraviolet rays generated by discharge (color PDP). is there.

Various methods are known for PDP construction, but in order to reduce the thickness of the PDP, an airtight container for containing discharge gas is constructed by sealing the periphery of a front glass plate and a back plate facing each other with sealing glass. Mostly adopted. Normally, low-priced soda-lime glass for windows is used for both the front and rear plates.

It is convenient to form a large number of fine discharge display cells at positions where a line-shaped anode and a line-shaped cathode intersect. In order to prevent erroneous discharge and color bleeding between adjacent cells, to support a pressure difference between the inside and outside of the panel, and to regulate the distance between electrodes, a partition is formed around the discharge cell.

The problems of this PDP are as follows. The driving voltage is higher than that of liquid crystal displays and the like, and the burden on the circuit is large. Light emission efficiency is low except for light emission by Ne gas, so that it has low brightness or short life.

Among these, as an improvement measure, there is a method in which a cathode forming material having a large secondary electron emission coefficient γ is used and driven at a low voltage. For example, LaB ₆ or a specific conductive oxide (Japanese Patent Application Laid-Open No. 3-176946, Japanese Patent Application Laid-Open No. 4-1994).
No. 1, Japanese Patent Application Laid-Open No. 4-104430, Japanese Patent Application No. 2-
No. 276180, Japanese Patent Application No. 2-284217, Japanese Patent Application No. 2
No. 288402, etc.) is used.

Many of these materials have lower conductivity than metals. Further, even if it is about the same as a metal, if it is used as a powder convenient for forming a cathode, it has a high melting point and hardness, so that the sinterability is poor and the contact resistance is large. Therefore, the resistance of the formed cathode layer becomes considerably large. In such a case, a low resistance layer is usually formed under the high resistance cathode layer. As a result, the wiring resistance can be reduced even with a thin and long linear cathode. Generally, it is convenient to form the low resistance layer with a metal.

The problems of using a high γ material as a cathode are as follows. That is, the so-called V of the voltage V and the current I
In the I characteristic, the upward slope of the portion from the normal glow to the abnormal glow is called the positive characteristic of the tube resistance. When this positive characteristic is large to some extent, uniform discharge can be formed even if the cathode area is large. However, if the positive characteristic is small, the discharge is biased among a large number of cells and also within the cells. In other words, a current is more likely to flow in the part that is easily discharged, and the discharge is concentrated in a part. However, the positive characteristic is smaller as the cathode of the high γ material has a lower driving voltage. Therefore, there is a drawback that the discharge is locally concentrated.

The location where the discharge is concentrated occurs stochastically within the formed cathode area. If the discharge concentration occurs between a plurality of cells on one cathode line, dot unevenness occurs, and if it occurs within one cell, the cell arrangement looks disjointed. In either case, the display quality is degraded.

Considering this discharge concentration from another angle, it can be said that the cathode area is too large as compared with the performance by the cathode material. Therefore, a proposal has been made to subdivide the cathode discharge surface with an insulator so as to have an area suitable for material performance (Japanese Patent Application No. 3-170351). This method is effective for securing a predetermined cathode area and preventing discharge concentration, but since the area through which the current flows is subdivided and the current density increases, there is a risk of excessive sputtering.

With respect to the above problems, it has been proposed to improve the life while maintaining the brightness (Technical Report of the Television Society of Japan, IPU 91-66, Tetsuo Sakai et al.). This uses a considerably higher gas pressure than the lowest firing voltage according to Paschen's law. Since there are many gas molecules, positive ions are relaxed and cathode sputtering can be prevented. At this time, since there are many gas molecules, the number of collision ionization of electrons also increases. In such a case, the above-mentioned positive characteristic of the tube resistance decreases even if γ of the cathode material increases.

In order to obtain high brightness, so-called pulse memory driving has been realized. If the positive characteristic is small, current runaway occurs. As a common method for preventing this, there are a constant current driving method and a method of adding a current limiting resistance to the anode. However, for pulse memory driving, it is necessary to add a current limiting resistor to each cell. This is because the value of the current flowing through one cathode differs depending on the number of data.

The limiting resistance provided in each cell is several 100 k.
Ω or more is appropriate. When such a high resistance is connected in series to the discharge circuit, the current pulse waveform becomes considerably dull. This hinders driving with short pulses necessary for a fine PDP having a large number of cells. Further, the current loss due to the resistance is large, and it is complicated to form a large number of high resistances.

As described above, the conventional PDP currently has some problems in forming a cathode.

[0015]

SUMMARY OF THE INVENTION The object of the present invention is to solve these problems of the prior art, and even if a cathode material having high characteristics is used, there is no local concentration of discharge, and even if the discharge gas pressure is high, An object of the present invention is to simply provide a PDP that does not deteriorate the positive characteristics.

[0016]

The above object of the present invention is achieved by providing a cathode with a low resistance portion and a high resistance portion, and forming these portions continuously.

That is, the PDP of the present invention is a DC type PDP in which a plurality of discharge display cells are formed at positions where a line-shaped anode group and a line-shaped cathode group intersect, and is formed in one discharge cell. A cathode is continuously formed from a low resistance portion having a sheet resistance of 10 Ω or less and a high resistance portion having a sheet resistance of more than 10 KΩ, and the cathode area of the high resistance portion is larger than the cathode area of the low resistance portion. To do.

The present invention will be described in more detail below. The PDP of the present invention is different only in the cathode configuration, and the others are publicly known PDs.
P technology can be applied. For example, various construction methods, forming materials, forming techniques, and the like. However, a more preferable example will be described below.

The cathode forming material in the present invention is not particularly limited, but has a perovskite type or a crystal structure similar to this, and is Li, Na, K, of the group Ia of the periodic table of elements.
Rb, Cs, Group IIa Mg, Ca, Sr, Ba, IIIa
Those containing a conductive oxide containing at least one element selected from the group consisting of Sc, Y and lanthanide elements are desirable. The methods and characteristics of using these materials are described in detail in the patent publications or patent applications exemplified in the prior art, and can be used in the present invention. Here, the crystal structure similar to the perovskite type means that the specific element has a non-stoichiometric ratio in the basic lattice of the perovskite type crystal, for example, K ₂ NiF ₄ type, pyrochlore type, tungsten bronze type and the like. Includes things that are very small or disordered and close to irregular shapes. The lanthanide element is L
a, Ce, Pr, Nd, Pm, Sm, Eu, Gd, T
h, Dy, Ho, Er, Tm, Yb and Lu.

The above-mentioned cathode forming material is useful because it can reduce the discharge voltage. It is considered that these conductive oxides contribute to the reduction of the discharge voltage because the secondary electron emission coefficient (γ) is large. However, since the measurement of γ is difficult, the reason is not clear. According to the experiment, it is particularly effective to contain the group IIIa element, and when the group Ia group or the group IIa is compounded with this, further lowering of the voltage becomes possible.

In the present invention, the cathode in one cell is composed of two parts, a low resistance part and a high resistance part, and the area of the high resistance part is made larger than the area of the low resistance part. The sheet resistance of the low resistance portion is 10Ω or less, the high resistance portion is more than 10 kΩ, and the low resistance portion and the high resistance portion are formed continuously. If the two resistance parts are separated, it is difficult for the discharge to spread smoothly. However, if the separation distance is small, for example, several tens μm or less, there is almost no problem. Further, it is desirable that the cathode surface material has almost the same discharge characteristics, and therefore it is convenient to pattern the same material at a time.

When the discharge current is increased with such a structure, first, glow discharge is started in the low resistance portion,
Then, the discharge of the low resistance part spreads. When the spread of discharge is less than the low resistance partial area and the cathode material is high γ when the current value specified by the voltage applied to the tube is reached, the discharge is locally concentrated even if driven at the same voltage. Will end up.
In PDPs having a cathode of high γ material, the positive characteristics of the tube are generally small. Therefore, it is considered that current runaway occurs locally. This tendency is that the current flowing in the low resistance part is
It is experimentally confirmed that the current continues for about half the specified current value or less. Therefore, the area of the high resistance portion needs to be larger than that of the low resistance portion.

On the other hand, when the current flowing through the low resistance portion is 1/10 or less of the specified current, the following problems are likely to occur. The rest of the specified current flows through the high resistance portion, but the tube voltage at this time is considerably higher than when the discharge is generated only in the low resistance portion. Therefore, the sputtering in the low resistance portion is increased. Moreover, since the resistance itself becomes large, the power consumption is also large. Further, the current pulse waveform is also apt to be dull. These situations are similar even if the cathode is not a high γ material. Therefore, the preferable high resistance partial area is 1 of the low resistance partial area.
It is over 10 times.

When the current is further increased from the state where the discharge spreads to the low resistance part, the discharge spreads to the high resistance part. The farther from the low resistance portion, the higher the resistance at the discharge tip. Therefore, the tube resistance increases as the discharge in the high resistance portion spreads.
That is, the tube exhibits positive characteristics regardless of the cathode material and gas pressure.
This positive characteristic can prevent current runaway. Therefore,
It is possible to omit the current limiting resistor outside the discharge display cell.
In other words, memory drive becomes possible. Of course, an external resistor may be provided to protect the circuit, but a small resistance value is sufficient.

The degree of positive characteristics also varies depending on the sheet resistance value of the high resistance portion, the area of discharge spread and the length of discharge spread from the low resistance portion. These are determined by the design, and are appropriately obtained by experiments. If the sheet resistance of the high resistance portion exceeds 10 kΩ, proper positive characteristics of the tube can be obtained. When it is 100 MΩ or more, discharge concentration is likely to occur in the low resistance portion before the discharge sufficiently spreads. Further, it is difficult to stably form the cathodes of a large number of cells using such a high resistance material. A more preferable sheet resistance value of the high resistance portion is 100 kΩ to 10 MΩ.

Such a resistance value can be easily realized by using the above-mentioned conductive oxide. It is known that the specific resistance of these conductive oxides is generally high. Even if the specific resistance is not an appropriate value, an appropriate resistance value can be obtained by mixing a conductive component and a high resistance component (which may be an insulator). Such techniques are common in thick film technology. The addition amount is preferably 40% by volume or less in the case of a conductive component and 60% by volume or less in the case of an insulating material within a range that does not impair the surface characteristics of the cathode. Alternatively, the resistance may be adjusted by changing the film thickness. It is often used in thin film technology. Of course, the two methods can be combined.

In addition to the conductive oxides described above, R
Oxides such as uO ₂ , ZnO and SnO ₂ and borides such as LaB ₆ can also be used.

If the insulator is on the surface of the cathode, there is a risk that the discharge will be spotted. As is well known, a discharge spread of about 10 to 50 μm exists at one discharge point. Therefore, if the particle size of the added insulator is set to be equal to or smaller than the spread at the discharge point, the discharge can be made uniform over the entire surface.

Of course, the area of the low resistance portion should not be zero. When a large number of discharge display cells arranged in a line are connected by a high resistance cathode, a uniform voltage cannot be displayed at both ends due to a voltage drop due to resistance. When a low-resistance wiring is provided outside the discharge display cell, the end portion of the discharge display cell near the wiring emits light, and the preferable central portion is dark. Further, all the discharge currents flow through the high resistance portion, so that power loss is large and a high power supply voltage is required. Further, it has a drawback that the current pulse waveform is dull due to the high resistance and high speed driving cannot be performed. About 1/30 to 1/4 of the discharge display cell is sufficient as the area of the low resistance portion. If it is less than 1/30, the current density becomes excessive and spatter increases. If it exceeds 1/4, discharge concentration is likely to occur in the low resistance portion.

In order to utilize the positive characteristics of the tube without degrading the display quality, it is advisable to subdivide the low resistance portion. This increases the connection length between the low resistance portion and the high resistance portion. Therefore,
The discharge area spread with the same voltage can be increased. This means that a cathode material having a high sheet resistance can be used. When the low resistance parts face each other, the discharge spreads from different parts of the high resistance part and eventually merges. In this case, at the boundary of the discharge, the discharge point spreads as described above. Therefore, after the coalescence, the discharge area does not increase even if the current slightly increases. That is, even if the current slightly changes, the discharge area does not change and the display quality can be prevented from being degraded.

Next, a preferable method of forming the low resistance portion and the high resistance portion will be described. The low resistance portion also preferably has a surface characteristic that the discharge sustaining voltage is small. Since the preferable materials generally have high specific resistance, it is not so easy to form a low resistance film. If the film thickness is increased to reduce the resistance, fine patterning becomes difficult. Addition of a large amount of low-resistance metal component deteriorates the surface characteristics. For example, the discharge sustaining voltage increases and the amount of spatter increases.

On the other hand, a material having a small specific resistance, for example, A
Surface characteristics of metals such as g, Al, Au, and Ni and oxides of C and In—Sn are not so good. However, there is no problem if these materials are also used as the base electrode of the cathode.
On the contrary, if a low resistance base electrode is used, a wide range of specific resistance of the surface material can be used. If the sheet resistance is 10Ω or less, it can also be used as a common wiring for many discharge display cells. These materials are selected in consideration of conductivity, easiness of formation, cost, wiring to be connected, terminals, and matching with high resistance portions.

Therefore, first, the base electrode having a small specific resistance is formed, and the cathode is formed so as to cover the base electrode with a material having good surface characteristics. Since the sheet resistance of such a cathode can be made sufficiently high, a portion which does not contact the base electrode becomes a high resistance portion and can be formed continuously with a low resistance portion which contacts the base electrode. Of course, the area of the high resistance portion needs to be larger than the area of the low resistance portion. A part of the base electrode can be exposed in a range that does not affect the discharge.

Further, in order to utilize the spread of discharge points, it is desirable that the contact portion between the base electrode and the surface cathode be subdivided. This includes a method of subdividing the base electrode itself and a method of inserting a subdivided insulating layer between the base electrode and the surface cathode. Various shapes are possible as the base electrode shape to be subdivided, but in the case of a fine PDP, the line width is required to be 40 μm or less. Thin film technology is commonly applied to such patterning. However, even an inexpensive thick film technique can be subdivided as follows.

In general, thick film ink is prepared by kneading solid powder and liquid vehicle. Usually, the liquid vehicle is a resin dissolved in a solvent, and if the amount of resin in the ink is appropriate, a continuous film is formed. At this time, if the amount of resin in the continuous film is slightly larger than the appropriate amount of resin, a mesh-shaped solid film can be formed. A mesh-shaped conductive film can be formed even by mixing insoluble resin and insulating powder. However, if the particle size of these mixed powders is small, the path of the conductive component becomes too thin, and the discharge current is likely to cause wire breakage. If the particle size is large, fine printing cannot be performed. A suitable size is around 10 μm.
In the case of the high resistance portion having such a size, the positive characteristics of the tube may not be fully utilized under the gas condition in which the discharge point spread is large. Therefore, it is a more preferable method to use a dissolved resin to obtain a mesh shape. It is also preferable to subdivide into a comb shape or a ladder shape instead of the mesh shape.

The same method as described above can be applied to the patterning of the insulating layer to be inserted. The same effect can be obtained by inserting a high resistance layer instead of the insulating layer.

In this way, a direct current type PDP having a low resistance portion and a high resistance portion and having a cathode formed by continuously forming them is obtained.

[0038]

EXAMPLES The present invention will be described in more detail below with reference to examples. It should be noted that conventionally known techniques are used for steps other than the description.

Before Example 1 , soda lime glass for windows was used as the back plate. A schematic plan view of the completed PDP is shown in FIG. 1 (a), and a sectional view thereof is shown in FIG. 1 (b). In the figure, 1 is a front glass plate, 2 is a back plate, 3 is a cathode, 4 is an anode, 5 is a phosphor, 6
Indicates a base electrode, and 7 indicates a partition. Table 1 shows the specifications of the PDP excluding the cathode.

[0040]

[Table 1]

A transparent conductive film of In--Sn oxide is deposited on the front glass plate 1 by sputtering and patterned to form an anode 4. The phosphor 5 is adhered in a state where a part thereof is exposed.

On the back plate 2, a base electrode 6 which also serves as a wiring and a cathode 3 which covers the base electrode 6 are formed. This base electrode was formed by sputtering Al. A line shape having a thickness of about 1 μm and a width of 40 μm is patterned in the central portion of the discharge display cell and also serves as a wiring common to each cell.

The ink for the cathode 3 has an average particle size of about
0.5 μm La_0.5Sr_0.5CoO ₃Conductive oxide powder
75 wt%, 3 wt% of Al powder with an average particle size of about 4 μm, flat
Y with a uniform particle size of about 0.3 μm₂O₃Dielectric powder 10wt% and
And an average particle size of about 4 μm SiO₂-B₂O₃-PbO-Al₂
O₃-ZnO glass powder 12 wt% solid powder total 1
00 parts by weight of 15 wt% ethyl cellulose in butyl
45-fold liquid vehicle dissolved in carbitol acetate
A kneaded product was prepared. Apply this ink to the base
Overprint and print parallel to the electrodes, dry and fire to form the cathode 3.
It was It has a thickness of about 15 μm and a width of 150 μm.
The sheet resistance is about 1 MΩ. Also, the high resistance part of the cathode
Was about 73% of the cathode area.

The partition wall 7 was formed as follows. Thickness 0.
The 42wt% Ni-6wt% Cr- Fe alloy plate is etched by 15mm, SiO ₂ -B ₂ O this as electrode
After electrodepositing ₃ -PbO-Al ₂ O ₃ -ZnO based glass powder,
By fusion bonding at 650 ° C., almost the entire surface was coated with a dense dielectric. The dielectric thickness is about 10 μm.

The front glass plate, the rear plate, and the partition wall are assembled at predetermined positions, and the periphery is sealed with a seal glass so that the gas container PD
P was formed. In the formation of each circuit and the like, thick film technology was applied to those not described, and the phosphor was fired at 500 ° C, and the others were fired at 560 to 580 ° C. The PDP is evacuated by a tip tube (not shown), and then the discharge gas is sealed therein to be chipped off.

The metal plate used for the partition wall was used as a so-called trigger electrode. The function of the trigger electrode is to accumulate electric charges on the surface of the dielectric inside the discharge display cell and to use this electric charge to cause preliminary discharge to surely and quickly perform the display discharge, which is a known technique.

When this PDP was driven without external resistance, uniform light emission was observed in each cell, and discharge local concentration at the cathode did not occur. The current value was stable at about 70 μA between the cells, and the current pulse waveform was slightly blunt.

Comparative Example 1 A PDP similar to that of Example 1 was formed except that the width of the base electrode was 130 μm. The high resistance part of the cathode was about 13% of the cathode area.

When this PDP was driven without an external resistor, a runaway of current was observed.
An external resistance of 00 kΩ was put in to stabilize the current in each cell. Non-uniform light emission was observed inside the cell, and the display quality was poor as a whole. This is because the discharge is locally concentrated. In addition, stable memory drive was not possible with this configuration.

Example 2 In the same structure as in Example 1, an insulating layer (not shown) was formed between the base electrode and the cathode. The insulating layer material was a low melting point glass to which Al ₂ O ₃ was added, and the base electrode was covered with a length of 90 μm left in the center of the cell. The thickness is about 15 μm.

Further, La is used as a conductive oxide material for the cathode.
A powder having an average particle size of about 0.5 μm in which 10 mol% of Li ₂ O was solid-dissolved in NiO ₃ was used. The sheet resistance of this cathode material was about 400 kΩ. The high resistance part of the cathode was about 89% of the cathode area. The driving result of this PDP was similar to that of the first embodiment.

Example 3 FIG. 2 shows a partial schematic plan view of a base electrode. In the same structure as in Example 1, a thick film Ag paste was used as the base electrode. When 2 times the amount of resin was added to the normal paste and printing and baking were performed, as shown in FIG.
A mesh film having holes of about m was formed. Line width 130
The thickness was about 7 μm in μm.

La _0.7 S as a conductive oxide material for the cathode
A powder of r _0.3 MnO ₃ having an average particle size of about 0.5 μm was used.
The sheet resistance of this cathode material was about 2 MΩ. Also,
The high resistance portion of the cathode was about 65% of the cathode area. The driving result of this PDP was similar to that of the first embodiment.

As can be seen from the above embodiments, it is obvious that the cathode structure of the present invention can be applied to various PDPs.

[0055]

According to the present invention described above, the following effects are exhibited. Since a positive characteristic can be given to each discharge display cell itself and current runaway can be prevented, external resistance can be omitted. For the same reason as above, even if the high γ cathode material and the discharge gas pressure where the local discharge concentration is likely to occur are high, the local discharge concentration can be avoided. Therefore, the driving voltage can be reduced, the life is long, and the display quality is not degraded. High-brightness display is possible because pulse memory drive is possible. Since the low resistance part is formed in the cathode of each cell,
High-speed driving is possible with less blunt current pulse waveform. Since the low resistance part is formed in the cathode of each cell,
Little power loss. Since the same method as the conventional one can be applied as the cathode forming method, a PDP which is easy to manufacture and inexpensive can be obtained.

[Brief description of drawings]

FIG. 1 is a partial schematic diagram of a PDP used in this example.

FIG. 2 is a partial schematic plan view showing an example of a base electrode.

[Explanation of symbols]

1: front glass plate, 2: back plate, 3: cathode, 4: anode,
5: phosphor, 6: base electrode, 7: partition wall.

[Procedure amendment]

[Submission date] June 28, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

With respect to the above problems, it has been proposed to improve the life while maintaining the brightness (Technical Report of the Television Society of Japan, IPU 91-66, Tetsuo Sakai et al.). This uses a considerably higher gas pressure than the lowest firing voltage according to Paschen's law. Since there are many gas molecules, positive ions are relaxed and cathode sputtering can be prevented. At this time, since there are many gas molecules, the number of collision ionization of electrons also increases. In such a case, as described above, the positive characteristic of the tube resistance becomes small even if γ of the cathode material is large.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

When the discharge current is increased with such a structure, first the glow discharge is started at one place in the low resistance portion, and then the discharge in the low resistance portion spreads. When the spread of discharge is less than the low resistance partial area and the cathode material is high γ when the current value specified by the voltage applied to the tube is reached, the discharge is locally concentrated even if driven at the same voltage. Will end up. In PDPs having a cathode of high γ material, the positive characteristics of the tube are generally small. Therefore, it is considered that current runaway occurs locally. It is experimentally confirmed that this tendency continues until the current flowing in the low resistance portion becomes about 1/2 or less of the specified current value. Therefore, the area of the high resistance portion needs to be larger than that of the low resistance portion.

Claims (3)

[Claims] 1. In a DC type plasma display panel in which a plurality of discharge display cells are formed at positions where a line-shaped anode group and a line-shaped cathode group intersect, the cathode formed in the one discharge display cell is: A plasma display characterized by being formed continuously from a low resistance portion having a sheet resistance of 10Ω or less and a high resistance portion having a sheet resistance of more than 10KΩ, wherein the cathode area of the high resistance portion is larger than the cathode area of the low resistance portion. panel. 2. The cathode forming material has a perovskite type or a crystal structure similar to this, and is Li, Na, K, Rb, Cs, or IIa group Mg of the group Ia of the periodic table of elements.
The plasma display panel according to claim 1, comprising a conductive oxide having at least one element selected from the group consisting of Ca, Sr, Ba, Sc of group IIIa, Y, and lanthanide. 3. The plasma display panel according to claim 1, wherein the cathode of the low resistance portion is subdivided into a mesh shape, a comb shape, or a ladder shape.