JP4820261B2 - Plasma display panel - Google Patents

Description

  The present invention relates to a technique for achieving low voltage driving and high-efficiency light emission in a plasma display panel, and facilitating both implementation of writing failure and initialization failure.

2. Description of the Related Art In recent years, plasma display devices capable of realizing a large screen with a thin and light weight are attracting attention in display devices used in computers, television receivers, and the like.
The plasma display panel (hereinafter referred to as “PDP”), which is a display unit of the plasma display device, is divided into a DC (direct current) type and an AC (alternating current) type, and the AC type in various aspects such as reliability and image quality. Therefore, the mainstream of the current PDP is the AC type.

FIG. 12A shows a configuration diagram of a main part of a conventional AC type PDP apparatus. As shown in FIG. 12A, the PDP 900 has a structure in which the discharge space 96 is sandwiched between the front panel 80 and the back panel 90.
In the front panel 80, the scanning electrode 82 and the sustain electrode 83 form a pair on the main surface of the glass substrate 81 and are formed in a stripe shape to form the display electrode pair 84.

The scan electrode 82 and the sustain electrode 83 are formed by laminating a metal bus electrode 822 and a bus electrode 832 on the main surfaces of the transparent electrode 821 and the transparent electrode 831.
The first dielectric layer 85 and the protective layer 86 are laminated in this order so as to cover the main surface of the front panel 80 in such a state.
The first dielectric layer 85 generally has a relative dielectric constant of about 12 and a thickness of about 40 μm.

The protective layer 86 determines the function of reducing the discharge start voltage by efficiently discharging secondary electrons with respect to the incidence of ions into the discharge space, and the statistical start time delay (hereinafter referred to as “discharge delay”). The protective layer 86 is formed by, for example, a sputtering method in which an MgO film is formed by sputtering.
In the rear panel 90, address electrodes 92 are formed in a stripe shape in the X-axis direction on the main surface of the glass substrate 91, and a second dielectric layer 93 is laminated so as to cover the main surface of the glass substrate 91 subjected to the above processing. A partition wall 94 is formed on the main surface of the second dielectric layer 93 with a positional relationship such that the address electrode 92 is interposed therebetween. A phosphor layer 95 is applied from the main surface of the second dielectric layer 93 to the side wall of the partition wall 94.

The front panel 80 and the back panel 90 formed as described above are bonded so that the surfaces on which the electrodes are formed face each other and the display electrode pair 84 and the address electrode 92 intersect with each other with a discharge space therebetween. The peripheral part is sealed with frit glass or the like.
In a discharge space formed by arranging the front plate and the back plate to face each other, a mixed gas of xenon / neon or xenon / helium is sealed as a discharge gas.

With the above configuration, in the PDP 900, discharge cells are formed in a region intersecting with the discharge space between the display electrode pair 84 and the address electrode 92, and the discharge cells are arranged in a matrix.
Address discharge for accumulating charges on the surface of the protective layer 86 is performed between the selected scan electrode 82 and the address electrode 92, and ultraviolet light used for image formation is used between the scan electrode 82 and the sustain electrode 83. Sustain discharge that generates

  In the plasma display device (not shown) including the PDP 900 having the above-described configuration, as shown in FIG. 13, 1) a ramp waveform voltage is applied to the scan electrode 82, the sustain electrode 83, and the address electrode 92 to generate a weak discharge. An initialization period for returning the discharge cell to the initial charge accumulation state; (2) applying a voltage between the specific scan electrode and the specific address electrode to generate an address discharge in the specific discharge cell, ie, writing Three periods are provided: an address period in which charges are accumulated in the discharge cells to be lit, and (3) a sustain period in which a voltage pulse is applied to the scan electrode and the sustain electrode to perform a sustain discharge. After that, an image is displayed.

In recent years, a method for increasing the Xe partial pressure in the discharge gas has been used as an effective method for reducing power consumption. However, when the Xe partial pressure is increased, the discharge delay in the initialization period increases, and the initializing discharge is reduced. It was found that failure (hereinafter referred to as “initialization failure”) was caused.
A cell in which initialization failure has occurred generates so-called white noise in which a cell that should not be lit is lit, and a cell whose discharge has failed in the address period is a cell that should be lit. However, there is a problem that it is difficult to obtain a good image display performance because so-called black noise is generated.

In order to solve such a problem, as shown in FIG. 10B, MgO fine particles 86a having high crystallinity are dispersed and arranged in the form of islands on the surface of the protective layer 70 of the conventional PDP 900 to improve the electron emission characteristics. Thus, there is a PDP in which the discharge delay is eliminated and the discharge probability is improved. (For example, Patent Document 1)
WO 2004/049375 PCT Gazette

However, in the PDP of Patent Document 1 in which the MgO fine particles 86a having high crystallinity are dispersed and arranged in the entire protective layer 86 to improve the electron emission performance, the charge holding ability is too small when a discharge gas having a high Xe partial pressure is used. Therefore, it has been found that the charge accumulated in the discharge cell during the initialization discharge escapes before reaching the address discharge, resulting in failure of the address discharge.
More specifically, the charge accumulated during the initialization period is dissipated when an address pulse is applied to the scan electrodes of other lines in the address period, and the scan electrodes and address electrodes of the own line are dissipated. When an address pulse is applied, a so-called write failure occurs in which regular address discharge cannot be performed due to insufficient charge.

  The charge retention capability that is the cause of writing failure is greatly related not only to the protective layer including the MgO fine particles but also to the configuration of the dielectric layer. Although it is necessary to take countermeasures, the dielectric layer is greatly involved in the drive voltage and luminous efficiency, so there are severe design restrictions on the protective layer and the dielectric layer. There is a problem that it is difficult to simultaneously carry out suppression of initialization failure and suppression of writing failure.

  The present invention has been made to solve such a problem, and provides a PDP that can achieve low voltage driving and high efficiency, and can easily perform both initialization failure and writing failure. With the goal.

  In order to achieve the above object, in the plasma display panel of the present invention, a front plate and a rear plate are disposed opposite to each other with a discharge space interposed therebetween, and the front plate is disposed on a side of the front substrate facing the discharge space. An electrode pair including one electrode and a second electrode, a dielectric layer, and a protective layer are sequentially stacked, and a third electrode that intersects the electrode pair with a discharge space is disposed on the back plate, and the intersection is performed. A plasma display panel in which discharge cells are formed at locations, wherein the dielectric layer has a relative dielectric constant of 4 or more and 10 or less, and the first electrode and the second electrode forming a pair are close to each other The first edge and the second edge are the edges, and the area sandwiched between the first electrode and the second electrode is the gap area. In the protective layer, on the extension in the thickness direction. The first edge, the second edge, and When the gap region is defined as a first corresponding region, a second corresponding region, and a gap corresponding region, respectively, the protective layer is formed on at least one of the first corresponding region, the second corresponding region, and the gap corresponding region. There is an unevenly distributed portion having a higher rate of containing a substance having a higher initial electron emission performance than regions other than the first corresponding region, the second corresponding region, and the gap corresponding region.

As described above, the plasma display panel according to the present invention has the first correspondence in the protective layer in any one of the first correspondence region, the second correspondence region, and the gap correspondence region having a high electric field strength during the initializing discharge. There is an unevenly distributed portion having a higher ratio of containing a substance having a higher initial electron emission performance than regions other than the region, the second corresponding region, and the gap corresponding region.
Here, the initial electron emission coefficient is not the secondary electron emission coefficient for ions that determine the discharge voltage, but the degree of discharge delay, that is, the statistical time from the start of voltage application to the start of discharge. It is a value indicating the degree of initial electron emission.

That is, since the substance having high initial electron emission performance is concentrated in a place where the electric field strength is high and the initial discharge is easy to start, the initial discharge can be promoted to enhance the initial electron emission performance effectively even with a small amount. .
Furthermore, since the protective layer is required not only to promote initial discharge but also to contradict the performance, that is, to retain electric charge, among the regions where the first electrode and the second electrode overlap, In a region excluding the first corresponding region and the second corresponding region (hereinafter referred to as “excluded region”), the initial electron emission performance is lower than that in the unevenly distributed portion, so that the performance of holding charges is enhanced.

That is, by causing the first corresponding region and the second corresponding region to function as a region for performing initial discharge and causing the exclusion region to function as a region for holding charges, the mutual correlation is weakened, and the protective film and The degree of freedom in designing the dielectric layer can be expanded.
As a result, in the design of the dielectric layer, even if the value of the relative permittivity is set to a wide range from 4 to 10 where low voltage driving and high efficiency can be implemented, initialization failure and writing failure occur. Was suppressed.

In the conventional dielectric layer, the relative dielectric constant is usually set to about 12.
Further, in the first electrode and the second electrode forming a pair, when the direction in which the distance between adjacent sides is the minimum is the short gap direction, the first edge and the second edge Each of the first electrode and the second electrode forming a pair occupies a region in which the length in the gap short direction from the opposite ends is within A, and the dielectric layer when the thickness and _{t d,} the length a and the thickness _{t d,} 0 <it is desirable to have the relationship a ≦ 0.6464t _d.

In a range satisfying the condition of d ≦ 0.646t _d, the region has a high electric field strength in the initialization period, and functions as a region for performing an initial discharge by concentrating a substance having a high initial electron emission performance in this region. In addition, by making the other regions function as regions for holding charges, the correlation between the regions can be further weakened, and the degree of freedom in designing the protective film and the dielectric layer can be expanded.

In the dielectric layer, it is desirable that the film thickness of the portion sandwiched between the electrode pair and the protective layer is 25 μm or more and 45 μm or less.
Thereby, the initial electron emission performance can be easily improved by arranging the fine particles containing metal oxide crystals having better crystallinity than the first protective film in the unevenly distributed portion.
The protective layer includes a first protective film laminated on the dielectric layer and a metal oxide crystal having higher crystallinity than the first protective film disposed on the first protective film. And the protective layer is composed of MgO as a main component, and Si, Ge, Ca as impurities in the unevenly distributed portion. The concentration of any one of Fe, Al, Ni, Na, and K may be higher than that other than the uneven distribution portion.

Thereby, initial electron emission can be easily achieved by increasing the concentration of any of Si, Ge, Ca, Fe, Al, Ni, Na, and K as impurities in the unevenly distributed portion of the protective layer to be higher than that of the unevenly distributed portion. Performance can be increased.
Further, the protective layer includes a first protective film laminated on the dielectric layer, the main component of which is all MgO, and a second protective film locally disposed on the first protective film. The second protective film has a higher concentration of any of Si, Ge, Ca, Fe, Al, Ni, Na, and K as impurities than the first protective film. The location is the unevenly distributed portion, or the protective layer is mainly composed of MgO, and the concentration of MgOH as an impurity in the unevenly distributed portion is higher than other than the unevenly distributed portion. Also good.

Thus, the initial electron emission performance can be easily improved by increasing the concentration of MgOH as an impurity in the unevenly distributed portion of the protective layer to be higher than that in the unevenly distributed portion.
Further, the protective layer includes a first protective film laminated on the dielectric layer, the main component of which is all MgO, and a second protective film locally disposed on the first protective film. The second protective film has a higher concentration of MgOH as an impurity than the first protective film, and the location of the second protective film is the unevenly distributed portion, or It is desirable that the uneven distribution portion is included in both the first corresponding region and the second corresponding region.

Thereby, the uneven distribution portion can be set in the region of the protective layer having a high electric field strength during the initializing discharge.
In addition, it is preferable that the uneven distribution portion is included in at least one of the first corresponding region and the second corresponding region.
Thereby, high luminous efficiency and low voltage driving can be implemented at the same time.

  The discharge gas preferably has a Xe partial pressure ratio of 15% to 100%.

In recent years, there has been a tendency to increase the Xe partial pressure in the discharge gas in order to improve the light emission efficiency. However, the problem of increasing the occurrence probability of write failure when the Xe partial pressure is increased is as follows. Also in the plasma display panel driven by the above, low voltage driving and high efficiency light emission can be achieved, and both writing failure and initialization failure can be suppressed.

(Embodiment 1)
1. Configuration Hereinafter, the PDP according to the first embodiment will be described in detail.
FIG. 1 is an exploded perspective view of the PDP 2 in the first embodiment.
In FIG. 1, PDP 2 is an AC-type PDP, which is disposed such that a front panel 10 and a rear panel 20 face each other with a discharge space interposed therebetween, and a sustain electrode is formed on the main surface of the glass substrate 11 in the front panel 10. 12 and the scan electrode 13 are arranged in parallel, and the scan electrode 13 and the sustain electrode 12 form a pair to form a display electrode pair 14.

  The sustain electrode 12 and the scan electrode 13 are disposed on the main surface of the transparent electrode 121 and the transparent electrode 131 on the discharge space side of the transparent electrode 121 and the transparent electrode 131 formed in parallel with each other with a strip-like ITO film, and are transparent. A bus electrode 122 and a bus electrode 132 extending in the Z-axis direction are disposed on the respective edge portions of the electrode 121 and the transparent electrode 131 that are the farthest in the X-axis direction.

The transparent electrode 121 and the transparent electrode 131 are made of a transparent conductive material such as ITO or SnO2, and are a strip-shaped thin film body having a thickness of 0.1 μm, and the longitudinal direction thereof is the Y-axis direction.
The bus electrode 122 and the bus electrode 132 are metal electrodes having a thickness of 7 μm and a width of 95 μm formed by using Ag as a material. The bus electrode 122 and the bus electrode 132 facilitate supply of electric charges to the sustain electrode 12 and the scan electrode 13. And adverse effects caused by the electrical resistance of the transparent electrode 131 are reduced.

In the glass substrate 11, the dielectric layer 15 and the protective layer 16 are laminated in this order so as to cover the discharge space side main surface on which the transparent electrode 121 and the transparent electrode 131 are formed.
The dielectric layer 15 is formed of a low-dielectric constant low-melting glass having a film thickness of 25 μm or more and 45 μm or less, and has a current limiting function peculiar to the AC type PDP.
The relative dielectric constant of the dielectric layer 15 is set in the range of 4 to 10.

Here, for the sake of convenience, the edges on the side where the transparent electrode 121 and the transparent electrode 131 are close to each other are collectively referred to as the display electrode both edges.
The protective layer 16 is a thin film body mainly composed of MgO and having a film thickness of 0.6 μm and formed by a thin film process typified by sputtering or CVD, and is scanned from high energy ions generated by discharge. The electrode 13, the sustain electrode 12, and the dielectric layer 15 are protected, and at the same time, the secondary electrons are efficiently emitted into the discharge space to reduce the discharge start voltage.

Here, for the sake of convenience, the edges on the side where the transparent electrode 121 and the transparent electrode 131 are close to each other are referred to as a first display electrode edge and a second display electrode edge, respectively.
On the surface of the protective layer 16 on the discharge space side, the fine crystal 116a and the fine crystal 116b are respectively arranged in the thickness direction, that is, the region where the first display electrode edge and the second display electrode edge exist in the Z-axis direction. It is installed.

In addition, regions where the fine crystal 116a and the fine crystal 116b are respectively disposed are referred to as a disposition region 116ra and a disposition region 116rb.
The fine particle crystal 116a and the fine particle crystal 116b are fine particles mainly composed of MgO and having a particle diameter of 0.1 μm or more and 10 μm or less, and the proportion of MgO having high crystallinity is included in the protective layer 16. Higher than that of the protective layer 16 and has a function of more easily discharging secondary electrons into the discharge space and facilitating the start of discharge.

As described above, the protective layer 16, the fine particle crystal 116a, and the fine particle crystal 116b are functionally similar in function, and both function while affecting each other. The crystal 116a and the fine particle crystal 116b can be considered as a part of the protective layer.
The position and size of the arrangement region 116ra and the arrangement region 116rb in which the fine particle crystal 116a and the fine particle crystal 116b are arranged are low voltage driving, high efficiency, discharge delay suppression, and write failure suppression. The details are described later.

As used herein, the term “fine particles” refers to those having a particle size of 0.1 μm or more and 10 μm or less.
In the rear panel 20, a strip-like address electrode 22 made of a metal film or a conductive paste is extended and disposed on the main surface of the glass substrate 21 of the rear panel 20 so as to intersect the display electrode pair 14 with a discharge space therebetween. ing.

A dielectric layer 23 is laminated on the main surface of the glass substrate 21 of the rear panel 20 so as to cover the address electrodes 22, and on the dielectric layer 23, a region sandwiched between the adjacent address electrodes 22. A partition wall 24 is formed in parallel with the address electrodes 22.
The partition wall 24 is made of low-melting glass, like the dielectric layer 23.
In the rear panel 20, for example, red, green, and blue phosphor layers 26 are applied from the main surface of the dielectric layer 23 to the side walls of the barrier ribs 24 for each discharge cell. The discharge cells having the respective phosphor layers 26 of red, green, and blue arranged in a group form one pixel for color display.

The discharge space sandwiched between the front panel 10 and the back panel 20 is filled with a discharge gas (Ne—Xe gas, He—Xe gas, etc.) at a pressure of about 60 kPa.
This embodiment is characterized in how to determine the position and size of the arrangement region 116ra and the arrangement region 116rb in which the fine particle crystal 116a and the fine particle crystal 116b are arranged, and will be described in detail below.
(Details of the location of the fine crystal)
2A is a plan view of the PDP 2 viewed from the extension of a straight line orthogonal to the main surface of the front panel, and FIG. 2B is obtained by crossing the XZ plane where the PDP 2 passes through the address electrodes 22. FIG.

As described above, on the surface of the protective layer 16 on the discharge space side, the arrangement area 116ra and the arrangement area 116rb are respectively provided in areas where the first display electrode edge and the second display electrode edge exist in the thickness direction. Exists.
The length A of the arrangement region 116ra and the arrangement region 116rb in the direction in which the electric force lines generated between the sustain electrode 12 and the scan electrode 13 are directed (hereinafter referred to as “electric force line direction”), and the dielectric layer 15 the thickness t _d, satisfy the following relation.

A = 0.6464t _d
Here, in Embodiment 1, since the pair of strip-like transparent electrodes 121 and transparent electrodes 131 are arranged in parallel with the Y-axis direction, the electric lines of force are in the X-axis direction. Yes.
If the gap between the transparent electrode 121 and the transparent electrode 131 is not parallel to the Y-axis direction, the electric lines of force deviate from the X-axis direction.

FIG. 2 (c) is an enlarged cross-sectional view of the fine particle crystal 116b, and FIG. 2 (d) is a view of the portion viewed from the Z-axis direction.
The situation of the fine crystal 116a is the same as that of the fine crystal 116b.
As shown in FIG. 2C and FIG. 2D, the fine particle crystals 116b are scattered at a uniform surface density in the arrangement region.

At this time, in the arrangement region 116rb, as shown in FIG. 2D, the ratio of the area in which the underlying protective layer 16 is covered with the fine particle crystals 116a (hereinafter referred to as “fine particle crystal coverage”) is 30%. It was.
2. Manufacturing method (arrangement method of fine crystal)
The fine particle crystal 116a and the fine particle crystal 116b are arranged by arranging a mask in a region other than the region 116ra and the region 116rb in the protective layer 16 after the protective layer 16 is formed, and forming a volatile liquid such as ethanol. Then, a liquid in which magnesium oxide fine particle crystals having a particle diameter of 0.5 μm to 2 μm were dispersed was applied and disposed by a printing method.

According to this method, the magnesium oxide fine particle crystals can be disposed at a low cost at a specific portion on the surface of the protective layer with a high fine particle crystal coverage.
As the volatile liquid volatilizes, the magnesium oxide fine particle crystals are arranged in the arrangement area 116ra and the arrangement area 116rb with a uniform surface density.
3. Design Method Hereinafter, how to determine the design parameters of the dielectric layer 15 and how to determine the arrangement positions of the fine particle crystals 116a and the fine particle crystals 116b in the PDP 2 will be described in detail.
1) Design Concept for Reduction of Drive Voltage and Reactive Power As described above, the dielectric layer 15 is greatly involved in the drive voltage and the light emission efficiency.

More specifically, as the capacitance of the dielectric layer 15 increases, the reactive power increases and the light emission efficiency decreases.
Further, as the thickness of the dielectric layer 15 increases, the drive voltage increases.
In the first embodiment, in consideration of the above circumstances, the dielectric layer 15 has a relative dielectric constant of 4 to 10 and a film thickness of 25 μm to 45 μm.

Hereinafter, the reason for this determination will be described.
(1) Conditions for Improving Luminous Efficiency FIG. 3 is a diagram showing the results of measuring the luminous efficiency when the relative dielectric constant and film thickness of the dielectric layer 15 are changed in the PDP 2.
The horizontal axis indicates the capacitance per unit area, and the vertical axis indicates the luminous efficiency.

Here, the capacitance per unit area (C / S) is the dielectric layer existing on the discharge space side in the thickness direction with reference to the transparent electrode 121 of the sustain electrode 12 or the transparent electrode 131 of the scanning electrode 13. It is a value obtained by dividing the capacitance (C) of the capacitor constituted by the dielectric layer 15 in the area of the area (S) of 15.
As shown in FIG. 3, it is desirable to drive in a place where the luminous efficiency is as high as possible.

In order to change the capacitance (C / S) per unit area, the parameters of the dielectric layer 15 that are actually changed are the relative permittivity (ε _s ) and the film thickness (t _d ). And the above-mentioned capacitance (C) can be obtained by the following equation.
[Formula 1] C = ε ₀ · ε _s (S / t _d )
ε ₀ : Dielectric constant of vacuum (8.854 * 10 ^-12 )
Therefore, the capacitance per unit area (C / S) is obtained by the following equation.
[Formula 2] C / S = ε ₀ · ε _s (1 / t _d )
From FIG. 3, the peak point of the luminous efficiency (peak value 3.26 (lm / W)) exists at the position where the electrostatic capacity per unit area (C / S) is 1.4 μF / m ² .

Then, in the right area (capacitance 1.4μF / m ² or more regions per unit area) than the peak point, an inflection point capacitance (C / S) is the position of 2.05μF / m ² (A point that is 1 / e in statistics) exists, and in the region on the right side of the inflection point, the slope of the curve indicating the luminous efficiency is gentle.
For this reason, the inventors considered that it is desirable to set the capacitance per unit area (C / S) to a region on the left side of this inflection point, that is, 2.05 μF / m ² or less. .
(2) Conditions for reducing driving voltage In addition, the inventors have gradually changed the film thickness of the dielectric layer 15 to change the capacitance per unit area (C / S). The status of changes in drive voltage was confirmed.

As a result, it was confirmed that in the range where the capacitance per unit area (C / S) is less than 1.4 μF / m ² , the drive voltage rises that cannot be handled by the current drive circuit.
For this reason, the inventors considered that the capacitance per unit area (C / S) is desirably 1.4 μF / m ² or more.
When the above-described range in which the capacitance per unit area (C / S) is less than 1.4 μF / m ² is converted into the film thickness range of the dielectric layer 15, the range exceeds 45 μm.

From the above results, the inventors set the capacitance (C / S) per unit area of the dielectric layer 15 to 1.4 μF / m in order to reduce the driving voltage of the PDP and increase the light emission efficiency. ² above, and concluded that it is desirable to below 2.05μF / m ^2.
In other words, it is expressed as follows.
[Formula 3] 1.4 μF / m ² ≦ C / S ≦ 2.05 μF / m ²
In this range, the luminous efficiency is 2.7 or more and 3.25 or less, and high luminous efficiency can be obtained.

In contrast, the conventional PDP has a dielectric layer thickness of 40 μm and a relative dielectric constant of 12, so the capacitance per unit area (C / S) is 2.7. The luminous efficiency is as low as about 2.5.
(3) Conditions for ensuring withstand voltage The inventors conducted tests and confirmed that the film thickness of the dielectric layer 15 is required to be 25 μm or more in order to ensure withstand voltage.

From the result of the film thickness lower limit value of the dielectric layer 15 derived from the dielectric strength voltage and the film thickness upper limit value derived from the limit of the drive voltage, the inventors have determined the film thickness t _d of the dielectric layer 15 as follows: It was concluded that it is desirable to set it to 25 μm or more and 45 μm or less.
In other words, it is expressed as follows.
[Formula 4] 25 μm ≦ t _d ≦ 45 μm
Here, when Expression 2 is substituted into Expression 3, the following expression is obtained.
[Formula 5] 1.4t _d / ε ₀ ≦ ε _s ≦ 2.05 t _d / ε ₀
Here, when ε ₀ = 8.854 * 10 ⁻¹² F / m and Equation 4 are substituted into Equation 5,
[Formula 6] 3.95 ≦ ε _s ≦ 10.4
That is, the relative dielectric constant of the dielectric layer 15 is desirably 4 or more and 10 or less.

Since the current dielectric layer has a relative dielectric constant of about 12, it has become clear that it is more advantageous to use a material having a relative dielectric constant smaller than that.
From the above results, in order to achieve both reduction of driving voltage and reduction of reactive power, the inventors set the film thickness of the dielectric layer 15 to 25 μm or more and 45 μm or less and the relative dielectric constant to 4 or more. It was concluded that it is desirable to make it 10 or less.
2) Regarding Design Concept for Suppressing Discharge Delay and Write Failure FIGS. 4 and 5 are simulation results of the electric field strength distribution on the surface of the protective layer 16 when the voltage application pattern in the initialization period shown in FIG. 13 is reproduced. Yes, the calculation conditions are shown below.
(Calculation condition)
Dielectric constant of dielectric layer: 12
Dielectric layer thickness: 40 μm
Protective layer thickness: 0.6 μm
For convenience, a line passing through the center position of the discharge cell on the surface of the protective layer 16 and parallel to the transparent electrode 121 and the transparent electrode 131 is referred to as a protective layer reference line.

The horizontal axis in FIG. 4 indicates the position on the protective layer reference line, and the vertical axis in FIG. 4 indicates the component in the thickness direction of the protective layer 16 in the electric field intensity distribution on the protective layer protective layer reference line. The component in the Z-axis direction shown in 2 (b) is shown.
The position of 0 on the horizontal axis in FIG. 4 corresponds to the center position in the discharge gap sandwiched between the transparent electrode 121 and the transparent electrode 131.

From FIG. 4, it has been found that even if the position in the X-axis direction of FIG. 2B changes on the surface of the protective layer 16, the electric field strength of the Z-axis direction component at that position does not change much.
On the other hand, the horizontal axis in FIG. 5 indicates the position on the protective layer reference line, and the vertical axis in FIG. 5 indicates the component in the electric force line direction in the electric field strength distribution on the protective layer reference line on the surface of the protective layer 16. That is, the component in the X-axis direction shown in FIG.

From FIG. 5, the X-axis direction component electric field strength increases as the distance from the center position of the discharge cell on the surface of the protective layer 16 increases.
It is known that the position where the discharge is most likely to be started in the initialization discharge is the surface of the protective layer 16 where the edge of the transparent electrode 131 on the center side of the discharge cell exists in the thickness direction. It has been.

From this, it can be seen that the position where the initial electrons can be emitted to become the starting point of the discharge is a region immediately below the transparent electrode where the electric field strength is high and the electric charge is stored.
In FIG. 5, when looking at the situation of the change in electric field strength accompanying the change in position on the protective layer reference line, the position corresponding to the inflection point other than the peak point, that is, the position corresponding to the 1 / e point used in the statistical method is the protection. The distance from the center position of the discharge cell on the layer surface is 66 μm.

The inventors focused on this inflection point, and on the surface of the protective layer, on the side farther from the center position of the discharge cell than this inflection point, the electric field strength gradient is a region, so that the initial electron It is considered that this is a region that does not contribute much to suppression of initialization failure due to a discharge delay in the initialization period.
On the other hand, in the region approaching the center of the discharge cell from the inflection point and immediately below the transparent electrode, there is a peak point of the electric field strength, and the gradient of the electric field strength is steep. , I think that it is a region that has a high probability of emitting initial electrons and contributes to the elimination of the discharge delay, and that such a region should concentrate substances that enhance the initial electron emission performance. .

In addition, the inventors of the present invention have also proposed a region where the design parameters of the dielectric layer that greatly influence the low-voltage driving and the light emission efficiency and a substance that enhances the initial electron emission performance should be concentrated, that is, the region 116ra and the region to be disposed. By correlating with the setting range of the region 116rb, it was considered that low voltage driving, high efficiency, initialization failure and suppression of writing failure can be implemented at the same time.
Therefore, the relationship between the design parameters of the dielectric layer and the setting ranges of the arrangement region 116ra and the arrangement region 116rb is derived.
3) Specification of Disposition Position of Fine Particle Crystal 116a and Fine Particle Crystal 116b For convenience, on the surface of the protective layer 16, the position where the end of the transparent electrode on the center side of the discharge cell exists in the thickness direction (hereinafter referred to as “first” The range from the “position” to the position where the inflection point exists (hereinafter referred to as “second position”) is referred to as an electric field strength steep region, and the lines of electric force from the first position to a certain second position. Let the length in the direction be d.

Since the value of 1 / e, that is, the position of the inflection point changes with changes in the thickness of the dielectric layer 15 and the relative dielectric constant, the length d of the region where the electric field strength is steep is also set to the thickness of the dielectric layer 15. Will change accordingly.
The inventors conducted simulations and derived the relationship between these parameters.
FIG. 6 is a diagram showing the relationship between the relative dielectric constant and film thickness of the dielectric layer and the length d.
The horizontal axis shows the film thickness t _d of the dielectric layer, shows the values of length d on the vertical axis.

As shown in FIG. 6, as the thickness of the dielectric layer 15 increases, the second position moves away from the first position and the value of d increases, and the ratio of the dielectric layer 15 increases. As the dielectric constant increases, the second position shifts closer to the first position and the value of the length d becomes shorter.
In FIG. 6, the lower right region of the straight line connecting the points indicating the calculation results is a region included in the above-described steep region of the electric field strength, and as the relative dielectric constant of the dielectric layer 15 increases, the straight line moves to the right. There is a tendency to approach downward, that is, the electric field intensity steep region tends to shrink.

FIG. 7 is a diagram in which the abscissa indicates the relative dielectric constant and the ordinate indicates the slope τ of the straight line in FIG.
As shown in FIG. 7, as the relative dielectric constant of the dielectric layer 15 gradually decreases to 12, 8, and 4, the slope of the straight line in FIG. 6 gradually decreases to 0.722, 0.665, and 0.639. It has become.
Here, the inventors have determined that the relative dielectric constant of the dielectric layer 15 is preferably 4 or more and 10 or less. Therefore, the relative dielectric constant of the dielectric layer 15 is 10 at the maximum. 6 is estimated from FIG. 7 to be 0.6464.

When the value of the dielectric constant of the dielectric layer 15 is 4 or more and 10 or less, when the slope τ of the straight line in FIG. 6 is 0.6464, the straight line is closest to the lower right, and the electric field intensity steep region can be taken. It is in the smallest state.
Therefore, the thickness t _d of the dielectric layer 15, 25 [mu] m or more, set at 45μm or less, the relative dielectric constant of the dielectric layer 15 4 or more, when set to 10 or less, fine particles to increase the initial electron emission performance The region where the crystal is disposed is a region (hereinafter referred to as “limited region”) in which d ₂ satisfying the following formula is a length in the direction of the lines of electric force (hereinafter referred to as “limited region”), starting from the first position. The region is necessarily included in the region where the electric field strength is steep.
[Formula 7] d ₂ = 0.6464t _d
Therefore, we have determined the value of the d ₂ to the value of the arrangement area 116ra and length A of the electric line of force direction of the arrangement region 116Rb.

From the above, in the dielectric layer 15, the dielectric constant of 4 or more, 10 or less, the thickness t _d, 25 [mu] m or more, if selected in the range of 45 [mu] m, i.e., high luminous efficiency and lower than the conventional When designing in a range where voltage drive can be achieved, the limited area is considered to be an effective place for improving the initial electron emission performance among the areas directly under the transparent electrode where charges are stored. Therefore, it was considered that the initial electron emission performance should be positively increased even at the expense of the electron holding ability.

On the other hand, in the region directly below the transparent electrode where charges are stored, in regions other than the limited region, it is considered that the charge retention capability should be higher than the initial electron emission performance and the dissipation of charges during the address period should be suppressed. It was.
In this way, the region directly under the transparent electrode is divided into a region responsible for initial electron emission and a region responsible for charge retention, and each region performs its function, thereby correlating the dielectric layer and the fine particle crystal. We thought that the degree of freedom in designing the fine crystal and dielectric layer could be expanded by weakening the relationship.

That is, the inventors found that a field strength steep region of the protective layer 16 surface, the length d ₂ from the first position in the electric power line direction in the region of up to 0.6464T _d, from regions other than this region However, by unevenly distributing a substance having a high initial electron emission performance, it is possible to simultaneously carry out suppression of initialization failure due to discharge delay in the initialization period, suppression of write failure, reduction of driving voltage and reduction of reactive power. I thought.

In order to confirm this, the inventors conducted a confirmation test.
(Confirmation test)
The inventors conducted a test and confirmed that the capacitance per unit area (C / S) does not significantly affect the discharge delay but affects the writing failure.
This is due to the fact that the smaller the value of capacitance (C / S) per unit area, the smaller the charge retention performance and the more likely the writing failure occurs.

The inventors have also confirmed that the partial pressure ratio of Xe in the discharge gas has little effect on the write failure and affects the initialization failure due to the discharge delay in the initialization period.
More specifically, when the partial pressure ratio of Xe in the discharge gas is 15% or more, initialization failure occurs due to discharge delay in the initialization period, and the frequency of initialization failure increases as the partial pressure ratio increases. There is a tendency.

In other words, the most severe condition for the write failure is that the capacitance (C / S) value per unit area is the smallest in the specified design range, that is, the relative dielectric constant is 4, and The dielectric layer has a film thickness of 25 μm, and the most severe condition for poor initialization is when the partial pressure ratio of Xe in the discharge gas is 100%.
From these, the test conditions in the confirmation test were set as follows.
(Test conditions)
Xe partial pressure ratio in discharge gas: 100%
(Specifications of products to be tested)
Example product: Same as PDP2 (particulate crystals 116a and 116b are provided in the arrangement regions 116ra and rb, respectively).
Comparative product 1: In PDP 2, fine crystal 116a, b is not disposed at all.

Comparative product 2: In PDP 2, fine crystal crystals 116a and 116b are formed on the entire surface of the protective layer 16.
Table 1 shows the relative dielectric constant and film thickness of the dielectric layer of each test object.

○：不良の発生が認められない。
×：不良が発生した。

○: No defect was observed.
X: A defect occurred.

From the above results, even when the Xe partial pressure ratio of the discharge gas, which is likely to cause initialization failure, is 100%, the dielectric constant and the film thickness of the dielectric layer 15 are changed, and the capacitance per unit area (C In the upper limit and the lower limit of the range in which / S) achieves high efficiency and low drive voltage, neither the initialization failure nor the address failure occurred in the example product.
In the comparative product 1 in which the fine particle crystals 116a and b are not disposed at all, initialization failure occurs at the upper and lower limits of the capacitance (C / S) per unit area, and the fine particle crystals 116a and b In the comparative product 2 in which is formed on the entire surface of the protective layer 16, an address defect occurs at the lower limit of the capacitance (C / S) per unit area.

In addition, when the Xe partial pressure ratio is in the range of 15% or more and less than 100%, both the comparative product 1 and the comparative product 2 are less frequently generated than the results of Table 1 with respect to the initialization failure and the address failure. Of course, in the product of the example, neither initialization failure nor address failure occurred in this range.
(Summary)
Range of relative dielectric constant and film thickness of dielectric layer for high luminous efficiency and low voltage drive, that is, relative dielectric constant is 4 or more and 10 or less, and film thickness is 25 μm or more and 45 μm or less. set in the range of, further, a field strength steep region of the protective layer 16 surface, providing area 116ra and installation zone length d ₂ from the first position in the electric line of force direction is 0.6464T _d It has been found that the initialization failure due to the discharge delay in the initialization period can be suppressed at the same time by causing the substance having higher initial electron emission performance than the region other than this region to be unevenly distributed in 116rb.
(Other matters)
In the first embodiment, the fine particle crystals 116a and the fine particle crystals 116b are disposed in the entire region corresponding to the display electrode both edges, that is, in the entire disposed region 116ra and the disposed region 116rb. However, the present invention is not limited to this, and the fine particle crystal 116a and the fine particle crystal 116b may be arranged in a part of the arrangement region 116ra and the arrangement region 116rb.

In this case, it is desirable to set the surface density of the fine crystal arranged in the partial region to be larger than that in the first embodiment.
That is, it is desirable to maintain the total mass of the arranged fine crystal even if the area of the region where the fine crystal is arranged is reduced.
Further, when the fine crystal is disposed in a part of the arrangement region 116ra and the arrangement region 116rb, the fine particle crystal is arranged in a place near the center of the arrangement region 116ra and the arrangement region 116rb on the discharge cell center side. It is desirable. This is because, as shown in FIG. 5, the electric field intensity at the end on the discharge cell center side, that is, the first position is higher than the other positions.

Therefore, when the arrangement region of the fine particle crystal is set to be equal to or less than the area of the arrangement region 116ra or the arrangement region 116rb, it is a region directly below the transparent electrode, that is, an end portion on the discharge cell center side immediately below the transparent electrode, that is, It is desirable that the distance A from the first position to the other end in the direction of the electric force line be a region that satisfies the relationship represented by the following equation.
[Formula 8] 0 <A ≦ 0.6464t _d
Further, in the PDP 2 of the first embodiment, the fine crystal is arranged in the two arrangement regions 116ra and the arrangement region 116rb, that is, the scan electrode side and the sustain electrode side. As shown in FIG. 13, since a positive ramp waveform voltage is applied to the scan electrode side, electrons are accumulated in the arrangement region 116ra on the scan electrode side. A fine particle crystal may be disposed only on 116ra.

Of course, when the polarity of the voltage to the scan electrode and the sustain electrode is reversed from the above, the fine particle crystal may be disposed only in the disposition region 116rb where the electrons are accumulated.
Further, in the PDP 2 according to the first embodiment, in the region sandwiched between the arrangement region 116ra and the arrangement region 116rb (hereinafter referred to as “discharge gap region”), fine particle crystals for improving the initial electron emission performance are arranged. However, the present invention does not exclude the disposition of the fine crystal in the discharge gap region. For example, the present invention is in the discharge gap region and close to the disposition region 116ra and the disposition region 116rb. The fine particle crystals may be disposed in the respective regions, or the fine particle crystals may be disposed in the entire discharge gap region.

Further, in addition to the arrangement region 116ra and the arrangement region 116rb, fine crystal may be arranged in the discharge gap region.
Hereinafter, such an example will be described.
(Modification 1)
FIG. 8 is an exploded perspective view of the PDP 3 in which fine particle crystals are disposed also in the discharge gap region with respect to the PDP 2 of the first embodiment.

The PDP 3 is the same as the PDP 2 except that a region where the fine crystal is disposed is newly added to the PDP 2.
Since the fine particle crystals are also disposed in the discharge gap region, in the PDP 2 of the first embodiment, only one fine particle crystal is disposed in one discharge cell, that is, only the fine particle crystal 16a. Accordingly, there is only one region where the fine crystal 16a is provided, that is, only the addition region 16r.

9A, 9B, 9C, and 9D are a plan view, a sectional view, a partially enlarged sectional view, and a partially enlarged view of the PDP 3, respectively.
As shown in FIG. 5, in the discharge gap region, that is, the region from 0 to 40 μm in distance, the electric field strength in the initialization period is high, but no electrode exists in the thickness direction of the protective layer, so that no charge is accumulated, Therefore, since the ability to emit initial electrons is small, it is considered that PDP3 is not much different from PDP2 in terms of influence on discharge delay and writing failure.

As shown in FIGS. 9A and 9B, in the PDP 3, the arrangement location of the fine particle crystal 16a passes through the center of the discharge cell and becomes a single band-like region orthogonal to the address electrode 22. Thus, the application of the fine crystal becomes easier than that of the PDP 2, and the structure is easy to manufacture rather than aiming at further improvement of the performance of suppressing the discharge delay and writing failure with respect to the PDP 2.
Further, as shown in FIG. 9 (b), the particulate crystal 16a in the electric line of force direction length value A ₂ is the length A to 2 times the value, the electric line of force direction of the discharge gap region a value obtained by adding the length L _0.
(Embodiment 2)
1. Configuration In the first embodiment, as the substance that enhances the initial electron emission performance, fine particles mainly composed of MgO and having a particle size of 0.1 μm or more and 10 μm or less are used. However, it is not limited to this, and it may be increased by using other substances.

In the first embodiment, the fine crystal is disposed on the protective layer in order to locally enhance the initial electron emission performance. However, the initial electron emission performance of the protective layer itself may be locally enhanced.
10 (a) and 10 (b) are a plan view and a cross-sectional view of the PDP 4 in which the initial electron emission performance of the protective layer itself is locally enhanced.
The difference between the PDP 4 of the second embodiment and the PDP 2 of the first embodiment is that the PDP 2 has the fine crystal 116a and the fine crystal 116b disposed on the protective layer 16, whereas the PDP 4 has a dielectric layer. 15 is composed of a protective layer 216a and a protective layer 216b having a high initial electron emission performance, and a protective layer 216c having a low initial electron emission performance. There is no difference.

Further, when viewed in a plan view, that is, when FIG. 2A is compared with FIG. 10A, an arrangement area 216ra that is an arrangement area of the protective layer 216a and the protective layer 216b of the PDP 4 and The arrangement region 216rb and the arrangement region 116ra and the arrangement region 116rb, which are the arrangement regions of the fine particle crystal 116a and the fine particle crystal 116b of the PDP 2, are at the same position.
Therefore, the arrangement region 216rc of the protective layer 216c having a low initial electron emission performance is a region other than the arrangement region 216ra and the arrangement region 216rb.

The composition of the protective layer 216c is a thin film body containing MgO as a main component, similarly to the protective layer 16 of the PDP 2 of Embodiment 1, and has the same initial electron emission property.
On the other hand, the protective layer 216a and the protective layer 216b are thin films mainly composed of MgO, and have a higher concentration of any of Si, Ge, Ca, Fe, Al, Ni, Na, and K than the protective layer 216c. ing.

The upper limit of the concentration of each impurity is shown below.
Si <300ppm, Ca <50ppm, Fe <50ppm, Al <250ppm, Ni <5ppm, Na <5ppm, K <5ppm
Thus, the reason for adding any one of Si, Ge, Ca, Fe, Al, Ni, Na, and K to MgO is to improve the initial electron emission performance, and such impurities are added to MgO. A method for enhancing the initial electron emission performance by this is known, and is described in, for example, US Patent Document US2004 / 0070341.

From the above results, the relative dielectric constant of the dielectric layer 15 that can achieve low voltage driving and high luminous efficiency is in the range of 4 to 10, and the film thickness is 25 μm to 45 μm. also, a field intensity steeply region of the protective layer 16 surface in a region of length d ₂ from the first position in the electric line of force direction until 0.6464T _d, initial electron emission performance than in the region other than the region By unevenly distributing a substance having a high value, it is possible to suppress both initialization failure and write failure due to discharge delay in the initialization period.

  In the PDP 4 according to the second embodiment, the protective layer 216a and the protective layer 216b having a high initial electron emission performance and a protective layer 216c having a lower initial electron emission performance are stacked directly on the dielectric layer 15. However, the present invention is not limited to such a configuration. For example, as in FIG. 2B, a normal protective layer 16 is laminated on the dielectric layer 15 and the initial electron emission performance is desired to be improved. Instead of providing the fine crystal 116a and the fine crystal 116b in the arrangement region 116ra and the arrangement region 116rb, a protective layer to which any one impurity of Si, Ge, Ca, Fe, Al, Ni, Na, and K is added May be further laminated.

Further, in the PDP 4 of the second embodiment, the discharge gap region sandwiched between the arrangement region 216ra and the arrangement region 216rb has not been doped with an impurity that improves the initial electron emission performance. The addition of impurities to the discharge gap region is not excluded.
(Modification 2)
11 (a) and 11 (b) are a plan view and a cross-sectional view of a PDP 5 in which impurities are added to MgO, which is a main component of the discharge gap region, with respect to the PDP 4 of the second embodiment.

This PDP 5 is the same as the PDP 4 except that a region to which impurities are added is newly added to the PDP 4.
In this PDP 5, since impurities are also added to the protective layer in the discharge gap region, one protective layer 216a and one protective layer 216b are provided in one discharge cell in the PDP 4 of the second embodiment. That is, only the protective layer 16a is provided, and accordingly, only one region to which impurities are added, that is, only the added region 16r.

As shown in FIG. 5, in the discharge gap region, that is, the region from 0 to 40 μm in distance, the electric field strength in the initialization period is high, but no electrode exists in the thickness direction of the protective layer, so that no charge is accumulated, Therefore, since the ability to emit initial electrons is small, it is considered that the influence on the discharge delay and writing failure is small.
As shown in FIG. 11A and FIG. 11B, in the PDP 5, the formation position of the protective layer 316a passes through the center of the discharge cell and becomes a single band-like region orthogonal to the address electrode 22. The formation of the protective layer 316a is easier than the protective layer 216a and the protective layer 216b, and the structure is easy to manufacture rather than further improving the performance of suppressing the discharge delay and writing failure with respect to the PDP 4.

Further, as shown in FIG. 11 (b), the length value of A ₃ in the protective layer 316a in the electric line of force direction, the length A to 2 times the value, the electric line of force direction of the discharge gap region a value obtained by adding the length L _0.
The method for forming the protective layer 316 is the same as the method for forming the protective layer 216 except that the masking range is different.

In the PDP 5 of the second modification, a protective layer 316a having a high initial electron emission performance and a protective layer 316b having a low initial electron emission performance are directly stacked on the dielectric layer 15. For example, as in FIG. 2B, a normal protective layer 16 is laminated on the dielectric layer 15, and fine crystal crystals are added to the addition region 16r on the protective layer 16 where the initial electron emission performance is desired to be improved. Instead of providing 16a, a protective layer to which any one of Si, Ge, Ca, Fe, Al, Ni, Na, and K is added may be further laminated.
(Modification 3)
In Embodiment 2, Modification 1 and Modification 2, any of Si, Ge, Ca, Fe, Al, Ni, Na, and K is included in MgO, which is the main component of the protective layer, in order to improve the initial electron emission performance. These impurities are added, but the initial electron emission performance can be improved by adding other impurities to MgO.

More specifically, in the formation of the protective film, a compound having a hydroxyl group (OH) is added in place of the impurities, that is, Si, Ge, Ca, Fe, Al, Ni, Na, K, and the protective film is formed. The initial electron emission characteristics can be improved by partially replacing MgO as a main component with MgOH.
Thus, it is known to improve the initial electron emission characteristics by replacing a part of MgO as a main component of the protective film with MgOH, and is described in, for example, US Patent Document US2004 / 0263733. .

  Therefore, instead of adding Si, Ge, Ca, Fe, Al, Ni, Na, K by adding impurities to the protective layer described above, a compound having a hydroxyl group (OH) is added, and the main component of the protective film is added. A configuration may be adopted in which MgO is partially substituted with MgOH.

  The present invention is applicable to display devices used for television receivers, computer monitors, and the like.

It is a disassembled perspective view of PDP in this Embodiment 1. FIG. (A) is a top view of PDP in Embodiment 1 of this invention, (b) is sectional drawing, (c) is a fragmentary sectional enlarged view, (d) is a partial planar enlarged view. In PDP in this Embodiment 1, it is a figure which shows the result of having measured the luminous efficiency at the time of changing the dielectric constant and film thickness of a dielectric material layer. It is a figure which shows the simulation result of the Z-axis direction component of the electric field strength distribution in the surface of a protective layer at the time of reproducing the voltage application pattern in an initialization period. It is a figure which shows the simulation result of the X-axis direction component of the electric field strength distribution in the surface of a protective layer at the time of reproducing the voltage application pattern in an initialization period. It is a figure which shows the relationship between the relative dielectric constant and film thickness of a dielectric material layer, and length d. FIG. 7 is a diagram showing the relative permittivity on the horizontal axis and the slope τ of the straight line in FIG. 6 on the vertical axis. It is a disassembled perspective view of PDP of the modification 1. FIG. (A) is a top view of PDP in the modification 1, (b) is sectional drawing, (c) is a fragmentary sectional enlarged view, (d) is a partial planar enlarged view. (A) is a top view of PDP in this Embodiment 2, (b) is sectional drawing. The top view of PDP in the modification 2 and (b) are sectional drawings. It is a disassembled perspective view of the conventional PDP. It is a figure which shows the voltage application pattern of a general PDP.

Explanation of symbols

2,3,4,5 PDP
DESCRIPTION OF SYMBOLS 10 Front panel 11 Glass substrate 12 Sustain electrode 12 Normal 13 Scan electrode 14 Display electrode pair 15 Dielectric layer 16 Protective layer 16a Fine particle crystal 16r addition area | region 20 Back panel 21 Glass substrate 22 Address electrode 23 Dielectric layer 24 Partition 26 26 Phosphor layer 116 Arrangement region 116 Fine particle crystal 116a Fine particle crystal 116b Fine particle crystal 116r Disposition region 116rb Disposition region 121 Transparent electrode 122 Bus electrode 131 Transparent electrode 132 Bus electrode 216 Disposition region 216 Protection layer 216a Protection layer 216b Protection layer 216c Protection layer 216r Arrangement region 316 Protective layer 316a Protective layer 316b Protective layer

Claims (1)

The front plate on which the display electrode pair, the dielectric layer, and the protective layer are formed, and the back plate are arranged to face each other.
The display electrode pair includes a first electrode and a second electrode with a discharge gap,
The region of the protective layer corresponding to the region having a width A (μm) from the end on the discharge gap side in the first electrode and the second electrode has a particle size of 0.1 (μm) or more than other regions. 10 (μm) or less and the ratio of containing fine particles mainly composed of MgO is high,
The relationship between the thickness t _d (μm) of the dielectric layer and the width A (μm) is
0 <A ≦ 0.6464t _d
A plasma display panel.

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