JP5059349B2 - Plasma display panel - Google Patents

Description

  The present invention relates to a plasma display panel, and in particular, to a technique for achieving both suppression of light emission efficiency reduction and suppression of discharge delay.

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.
This plasma display panel (hereinafter referred to as “PDP”) is classified into a DC (direct current) type and an AC (alternating current) type, and the AC type is excellent in various aspects such as reliability and image quality. The mainstream is AC type.

FIG. 8 shows a configuration diagram of a main part of a conventional AC type PDP apparatus. As shown in FIG. 8, the PDP 900 has a structure in which a discharge space 96 is sandwiched between a front panel 80 and a 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 stripes to form the display electrode pair 84.
Scan electrode 82 and sustain electrode 83 are formed by laminating metal bus electrode 822 and bus electrode 832 on the main surfaces of transparent electrode 821 and 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 protective layer 86 is formed by using, for example, a sputtering method in which an MgO film is formed by sputtering.
Further, on the main surface of the glass substrate 81 where the display electrode pairs are not formed, black stripes 817 are formed along the adjacent display electrode pairs.

  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.
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
By the way, in recent PDPs, those with high definition specifications have begun to spread, and the time that can be allocated to one pulse of address discharge per discharge cell (hereinafter referred to as “address”) due to the increase in the number of cells accompanying high definition. “Pulse time”) is shortened, so that the probability of normal address discharge (hereinafter referred to as “discharge probability”) decreases.

  Specifically, the decrease in the discharge probability is caused by the slow time from the application of the voltage to the start of the address discharge (hereinafter referred to as “discharge delay”), and the discharge delay is remarkable. As the address discharge becomes difficult to finish within the address pulse time, there is a problem that a so-called writing failure that the sustain discharge cannot be carried out without accumulating charges tends to occur.

Thus, a cell in which writing failure has occurred becomes a non-lighted cell, so-called black noise is generated, and this makes it difficult to obtain good image display performance.
In order to solve such a problem, as shown in FIG. 8, MgO fine particles 86a having high crystallinity are dispersed and arranged in the shape of islands on the surface of the protective layer 70, thereby improving the electron emission characteristics, thereby reducing the discharge delay. There is a PDP that has been solved to improve the discharge probability. (For example, Patent Document 1)
WO2004 / 049375

However, when the fine particle crystals are dispersed and arranged on the surface of the protective layer as described above, the visible light striking the fine particle crystals is irregularly reflected. Therefore, the visible light emitted from the phosphor is irregularly reflected when transmitted to the outside of the panel, and the transmittance is high. Since it falls, there exists a problem that the luminous efficiency of a panel is impaired.
The present invention has been made to solve such a problem, and an object of the present invention is to provide a PDP capable of achieving both suppression of light emission efficiency reduction and suppression of discharge delay and a manufacturing method thereof. To do.

In order to achieve the above object, the plasma display panel of the present invention is characterized by the following.

1) A front plate and a back plate are arranged opposite to each other with a discharge space interposed therebetween, and the front plate is arranged on the side facing the discharge space with a display electrode pair including a scan electrode and a sustain electrode, a dielectric layer, and a protective layer. Are stacked in sequence, and on the back plate, an address electrode intersecting the display electrode pair with the discharge space is disposed, and a discharge cell is formed at the intersecting location, the plasma display panel, Fine particles containing metal oxide crystals are disposed on the surface of the protective layer, and the region of the surface of the protective layer facing either the display electrode pair or the address electrode is defined as a first region, and the scanning electrode and the When the region on the surface of the protective layer facing the constricted portion sandwiched between the sustain electrodes is a second region, the first region on the surface of the protective layer is included in the first region and the second region. And in areas other than the second area That than the surface density of the particles, have a partial surface density is large of the fine particles, the area surface density is large of the fine particles, than the area compared to the area surface density of the fine particles is small, it is arranged The fine particles having high crystallinity .

  Since fine particles containing metal oxide crystals can be produced alone, they are not easily affected by the base as in the case of forming a protective layer by a general sputtering method, and the degree of freedom of production conditions is large. Crystallinity is likely to be higher than that of the protective layer. By disposing such fine particles on the surface of the protective layer, it is possible to promote initial discharge and eliminate the discharge delay, but on the other hand, since the light hitting the fine particles is irregularly reflected, the surface of the protective layer is The translucency of the area where the fine particles are disposed is lowered.

In the configuration of the PDP according to 1) of the present invention, the PDP is sandwiched between the first region on the surface of the protective layer facing either the display electrode pair or the address electrode, and between the scan electrode and the sustain electrode. in the second region of the area on the protective layer surface in constriction facing you are, have a partial surface density is large of the fine particles than the surface density of the particles in other than these areas, the surface density of the fine particles The region where the particle size is large is made to have higher crystallinity of the arranged fine particles than the region where the surface density of the fine particles is smaller than the region .

This first region includes a region where the distance between the electrodes is short and the electric field strength reaches a peak when a voltage for address discharge is applied. Therefore, when the same amount of fine particles are disposed, the first region is a region where the electric field strength is low. When the fine particles are arranged in the first region at a higher density than in the regions other than the first region, the range of improvement in the initial electron emission performance is larger.
As described above, the fine particles are concentrated in the first region where the discharge performance improvement range is large, that is, the fine particles have a high surface density and are arranged in some regions where the discharge performance improvement effect is large. As a result, the total amount of fine particles to be disposed can be reduced, light transmission deterioration can be reduced, and light emission efficiency can also be reduced.

That is, it becomes possible to carry out both the suppression of the decrease in luminous efficiency and the suppression of the discharge delay.
By the way, since the peak exists at the sustain electrode side end of the scan electrode, the surface density of the fine particles in the region of the protective layer surface facing both the scan electrode and the address electrode is reduced in all regions other than this region. It is conceivable to increase the surface density of the fine particles, but in this case, the light transmission performance differs between the scan electrode side and the sustain electrode side with respect to the center of the discharge cell. There is a possibility that the brightness when viewing an image is different.

  For this reason, as in the structure of the PDP in 1) above, the area of the surface of the protective layer facing the sustain electrode and the address electrode that does not contribute to the address discharge is dared to reduce the surface density of the fine particles between the scan electrode and the address electrode. By arranging the fine particles in the same area as the surface area of the opposing protective layer, the light transmission performance on the scan electrode side and the sustain electrode side is made uniform so that the luminance does not differ in the viewing direction. It is effective for.

Further, when the region of the surface of the protective layer facing the display electrode pair is a third region, the area density of the fine particles in the fourth region including the second region and the third region is It is larger than the surface density of the fine particles in all regions other than the fourth region on the surface of the protective film, or opposed to two end portions that are close to each other in each of the scan electrode and the sustain electrode of the display electrode pair When the region of the surface of the protective layer that is being used is the fifth region, the area density of the fine particles in the sixth region including the fifth region and the second region is other than the sixth region of the surface of the protective film. It may be larger than the surface density of the fine particles in all regions.

Normally, only one display electrode pair is provided for each discharge cell, and each discharge cell has only one fine particle arrangement region. It is easy to arrange without being complicated.
Further, in each of the scan electrode and the sustain electrode of the display electrode pair, when the region of the surface of the protective layer facing two end portions that are close to each other is a fifth region, the region in the fifth region is The surface density of the fine particles may be larger than the surface density of the fine particles in all regions other than the fifth region on the surface of the protective film.

The end portion of the scan electrode becomes a peak region of the electric field intensity distribution when a voltage for address discharge is applied.
Since the fifth region includes this peak region, by concentrating and arranging the fine particles in the fifth region, the rate of decrease in translucency can be reduced to reduce the decrease in luminous efficiency, and the initial stage. Electron emission performance can be improved efficiently, and suppression of discharge delay can be promoted.

In addition, the fine particles have both high crystallinity that contributes to suppression of discharge delay and low crystallinity that does not contribute to suppression of discharge delay, and has high crystallinity that contributes to suppression of discharge delay. Since the existence probability is very low, in order to eliminate the discharge delay, it is necessary to make sure that the place where the fine particles are to be disposed includes a highly crystalline material.

As described above, by arranging fine particles with high crystallinity in a region where the surface density of the fine particles is high, that is, a place where the fine particles are to be arranged, it is possible to ensure that the crystalline particles are more crystalline. High things can be included .

(Embodiment 1)
(Constitution)
Hereinafter, the PDP according to the present embodiment will be described in detail.
FIG. 1 is an exploded perspective view of a PDP 1 in the present embodiment.
In FIG. 1, the PDP 1 is arranged such that a front panel 10 and a rear panel 20 face each other with a discharge space interposed therebetween, and a sustain electrode 12 and a scan electrode 13 are arranged on the main surface of a glass substrate 11 in the front panel 10. The scanning electrode 13 and the sustain electrode 12 are paired to form a display electrode pair 14, and a black stripe 17 a is formed in a region sandwiched between adjacent display electrode pairs 14 on the outer side of the main surface of the glass substrate 11. Is arranged.

The sustain electrode 12 and the scan electrode 13 are disposed on the discharge electrode side main surface of the transparent electrode 121 and the transparent electrode 131, and the transparent electrode 121 and the transparent electrode 131, respectively, formed in each discharge cell with a rectangular ITO film, and The bus electrode 122 and the bus electrode 132 extend in the Z-axis direction along the X-axis direction ends of the transparent electrode 121 and the transparent electrode 131, respectively.
Here, the discharge cell is a PDP region corresponding to a sub-pixel corresponding to one of R, G, and B components of one pixel, and has a grid-like partition wall. In the PDP 1, when the PDP is seen through from an extension of a straight line orthogonal to the main surface of the front panel 10 (hereinafter, such a view is referred to as “when seen through in plan view” for convenience). In each of the two types of partition walls having different directions, when a pair of adjacent ones is a first partition pair and a second partition pair, a region divided by the intersection of the first partition pair and the second partition pair is The same applies to other embodiments.

The transparent electrode 121 and the transparent electrode 131 are made of a transparent conductive material such as ITO or SnO2, are rectangular thin films having a thickness of 0.1 μm and a width of 150 μm, and the longitudinal direction thereof is the X-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 the transparent electrode 121. 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 main surface of the discharge space on which the transparent electrode 121 and the transparent electrode 131 are formed. Fine particle crystals 16a are intensively arranged in the center of the cell.
The protective layer 16 is formed by a thin film process typified by a film forming method using an EB vapor deposition machine, a plasma gun vapor deposition machine, or the like, a sputtering method, a CVD method, or the like. The scan electrode 13, the sustain electrode 12, and the dielectric layer 15 are protected from ions, and at the same time, the secondary electrons are efficiently emitted into the discharge space to reduce the discharge start voltage.

The fine-particle crystal 16a is a fine particle having a thickness of 0.1 μm or more and 10 μm or less and containing MgO produced as a main component, and the proportion of MgO having high crystallinity is higher than that of the protective layer 16. Higher than the protective layer 16, it has a function of more easily discharging secondary electrons into the discharge space and facilitating the start of discharge.
The fine particles referred to here are 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 discharge space side main surface of the glass substrate 21 of the rear panel 20 so as to cover the address electrodes 22, and corresponds to a region where the address electrodes 22 and the display electrode pair 14 intersect with each other with a discharge space therebetween. Thus, grid-like partition walls 24 and 25 are arranged on the main surface of the dielectric layer 23 so as to partition the discharge space.

The partition walls 24 and 25 are made of low-melting glass similarly to 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 and 25 for color display. A set of discharge cells each having red, green and blue phosphor layers 26 arranged in the extending direction forms 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 (such as Ne—Xe gas or He—Xe gas).
The grid-like barrier ribs 24 and 25 are arranged in the extending direction of the barrier ribs 25 and the address electrodes 22 arranged in the extending direction of the display electrode pair 14 in order to facilitate the exhaust process and the introduction of the discharge gas at the time of manufacturing the PDP. The partition 24 in the extending direction of the address electrode 22 is provided so as to be higher than the partition 25 in the extending direction of the display electrode pair 14.

In the present embodiment, there is a feature in the region where the fine crystal 16a is disposed, and therefore, this will be described in detail below.
(Regarding the arrangement region of the fine crystal 16a)
2A is a plan view of the PDP 1 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 1 passes through the address electrode 22. FIG.

As shown in FIGS. 2 (a) and 2 (b), when the protective layer 16 is seen through the extension of a straight line orthogonal to the main surface of the front panel, the arrangement region 16r of the fine crystal 16a on the surface of the protective layer 16 is as follows. In the transparent electrode 113 on the scanning electrode side and the transparent electrode 112 on the sustaining electrode side that form a pair, it is a rectangular region that covers two adjacent end portions and a region therebetween.
FIG. 2C is an enlarged cross-sectional view of the fine particle crystal 16a, and FIG. 2D is a view of the portion viewed from the Z-axis direction.

As shown in FIG. 2C and FIG. 2D, the fine crystal 16a is scattered with a uniform surface density in the arrangement region.
At this time, in the arrangement region 16r, as shown in FIG. 2D, the ratio of the area in which the underlying protective layer 16 is covered with the fine particle crystals 16a (hereinafter referred to as “fine particle crystal coverage”) is 30%. It was.
(Reason for determining the arrangement position of the arrangement area 16r)
3 (a) and 3 (b) show the electric field strength on the surface of the front panel on the discharge space side when an applied voltage for address discharge is applied to the address electrode and the scan electrode bus electrode in the conventional PDP. It is a figure which shows the result calculated | required by simulation (henceforth "address electric field strength").

The distribution of the address electric field strength is not affected by the presence or absence of fine particles on the protective layer.
FIG. 3A is a diagram showing an address electric field intensity distribution on the surface of the protective layer on the address electrode.
From FIG. 3A, it can be seen that the portion having the highest address electric field strength on the surface of the protective layer on the address electrode is a region facing the end of the scan electrode on the discharge cell center side.

FIG. 3B is a diagram showing an address electric field intensity distribution on the surface of the protective layer in a direction passing through the end of the scan electrode on the discharge cell center side and orthogonal to the address electrode 22.
As shown in FIG. 3B, the portion having the highest address electric field strength on the surface of the protective layer passing through the end portion of the scan electrode on the discharge cell center side and orthogonal to the address electrode 22 is the center of the discharge cell of the scan electrode. It turns out that it is an edge part of the side.

From these results, it can be seen that the highest point of the address electric field strength in the protective layer 16 is the end of the scan electrode on the discharge cell center side.
Since the initial electron is more likely to be emitted at the portion where the address electric field strength is higher, the fine particle crystal 16a is disposed so as to cover the portion where the address electric field strength is higher.
More specifically, the arrangement region 16r of the fine particle crystal 16a is divided into a rectangular region that covers two adjacent end portions of the transparent electrode 121 of the scanning electrode 13 and the transparent electrode 131 of the sustain electrode 12 and a region therebetween. did.

As described above, the delay of discharge can be suppressed by disposing the fine particle crystal 16a in a place that originally has a high initial electron emission performance and further improving the initial electron emission performance.
Further, since the discharge range after the start of discharge extends to the periphery of the discharge starting point, the discharge electrode is disposed in a region deviating from the region of the end portion on the discharge cell center side of the scan electrode having a high address electric field strength. The fine particle crystal 16a contributes to the promotion of the expansion of the discharge range.

Further, the arrangement region 16r of the fine particle crystal 16a is concentrated in the central portion of the discharge cell, and the amount of fine particle crystal used per discharge cell is reduced, so that the light transmission performance is greatly reduced. Without incurring, it is possible to improve the initial electron discharge characteristics and suppress an increase in manufacturing cost.
Further, since the fine crystal 16a is arranged symmetrically with respect to a straight line passing through the center of the discharge cell perpendicular to the address electrode 22, there is no difference in translucency between the left and right, and the luminance differs in the viewing direction. It is effective to prevent it from happening.

That is, there is no possibility that the luminance of the image differs when the screen is viewed obliquely from the left side and the right side.
(Translucent performance)
FIG. 4 shows the front surface of the discharge cell when the ratio of the area of the fine particle crystal 16a to the entire area of the protective layer 16 is changed (hereinafter referred to as “area ratio of the fine particle crystal arrangement area”). It is a figure which shows the change of the transmittance | permeability of visible light (henceforth "visible light transmittance") which permeate | transmits the panel 10 in the thickness direction.

At this time, the fine particle crystal coverage in each arrangement region of the fine crystal 16a was kept constant at 30%.
As shown in FIG. 4, for example, in the conventional PDP as in Patent Document 1, when the fine crystal is disposed on the entire surface of the protective layer 16 in the discharge cell, the fine crystal coverage is 100 %. The visible light transmittance is 41%.

The visible light transmittance is 57% when no fine particles are disposed on the protective layer 16 in the discharge cell. Compared with this, when the fine particle crystals are disposed on the entire surface of the protective layer 16 in the discharge cell. The visible light transmittance is reduced by 16%.
In the present embodiment, the fine particle crystal coverage is 30%, and the area ratio of the fine crystal crystal arranged region is 30%, and the visible light transmittance at this time is 53%. That is, the visible light transmittance is only 4% lower than when no fine particles are provided in the protective layer 16 in the discharge cell, and fine particle crystals are provided over the entire protective layer 16 in the discharge cell. Compared with the case where the visible light transmittance is 12%.
(About discharge delay)
FIG. 5 is a graph showing the relationship between the area ratio of the fine particle crystal arrangement region in the discharge cell and the discharge start time ratio when the fine particle crystal coverage in the fine crystal crystal arrangement region is 30%.

  Here, the discharge start time ratio is the time from application of a voltage between the address electrode 22 and the scan electrode 13 to the start of address discharge (hereinafter referred to as “discharge start time”). Since it is determined according to the area ratio of the region, when the discharge time when no fine particles are provided in the protective layer 16 of the discharge cell is used as the reference discharge time, the ratio of the discharge start time to the reference discharge time is expressed as a percentage. It is displayed.

As shown in FIG. 5, when the area ratio of the fine particle crystal arrangement region changes in the range of 0% or more and 50% or less, the rate of change of the discharge start time ratio accompanying this is large.
In addition, when the area ratio of the fine particle crystal arrangement region exceeds 50% and changes within a range of 100% or less, there is almost no change in the discharge start time ratio.
For this reason, in order to shorten the discharge start time, there is not much meaning in setting the area ratio of the fine crystal arrangement region to exceed 50%.

In the present embodiment, the fine particle crystal coverage is 30% and the area ratio of the fine crystal crystal arranged region is 30%, and the discharge start time ratio at this time is 42%.
That is, the discharge start time is less than half compared to the case where no fine particles are provided in the protective layer 16 in the discharge cell.
Further, compared to the case where fine particles are provided on the entire surface of the protective layer 16 in the discharge cell, the discharge start time ratio in this case is 34%, and therefore the discharge start time ratio of the PDP 1 of the present embodiment is 8% larger. Although it seems to be slightly disadvantageous, in view of the visible light transmittance, the PDP 1 of the present embodiment is 12% larger, and considering that it is advantageous, the discharge delay suppression performance does not change much. It can be said that the light transmission performance is improved.

In addition, the visible light transmittance is hardly lowered only by reducing the area ratio of the fine particle crystal arrangement region to only 5%, and the discharge starts compared with the case where no fine particles are arranged in the protective layer 16 in the discharge cell. Since the time ratio can be reduced by 16%, it is preferable to set the area ratio of the fine-crystal arrangement region to 5% or more.
From the above, when the fine particle crystal coverage is 30%, the area ratio of the fine particle crystal disposition region is desirably 5% or more and 50% or less.

Further, when the effect on the discharge delay was confirmed by gradually decreasing the fine particle crystal coverage from 30%, no remarkable deterioration was observed until the fine particle crystal coverage reached 20%. Accordingly, the fine crystal coverage is preferably 20% or more.
This is because fine particles have high crystallinity that contributes to suppression of discharge delay and low crystallinity that does not contribute to suppression of discharge delay, and high crystallinity that contributes to suppression of discharge delay. This is considered to be because a certain amount is required to suppress the discharge delay because the existence probability is very low.

That is, it is considered that the necessary amount is satisfied by setting the fine particle crystal coverage to 20% or more.
(Method of disposing the fine crystal 16a)
The fine particle crystal 16a is disposed by forming a mask in a region other than the region 16r in the protective layer 16 after the protective layer 16 is formed, and in a volatile liquid such as ethanol having a particle size of 0.5 μm to 2 μm. A liquid in which the magnesium oxide fine particle crystals were dispersed was applied and disposed by a printing method.
According to this method, the magnesium oxide fine particle crystal can be disposed at a low cost on a specific portion of the surface of the protective layer with a high fine particle crystal coverage, and the magnesium oxide fine particle crystal is formed along with the volatilization of the volatile liquid. Since it is dispersedly arranged on the surface of the protective layer with a uniform surface density, the uneven distribution of magnesium oxide fine particle crystals is small.

In the PDP 1 of the present embodiment, since one arrangement region 16r exists for each discharge cell, the liquid containing the magnesium oxide fine particle crystals is easily applied.
As described above, the PDP 1 of the present embodiment concentrates the fine crystal 16a in a place that originally has a high initial electron emission performance, and further improves the initial electron emission performance, thereby reducing the discharge delay. While suppressing, the usage-amount of the fine particle crystal | crystallization per discharge cell can be decreased, the drastic fall of translucency can be suppressed, and the fall of luminous efficiency can be suppressed.

That is, it becomes possible to carry out both the suppression of the decrease in luminous efficiency and the suppression of the discharge delay.
Hereinafter, the influence of the fine crystal 16a on the electron emission performance will be described in detail.
When an electric field is applied to magnesium oxide during address discharge, the Fermi level in the band increases and the carrier density of the protective layer increases.
Correlated with this carrier density, initial electron emission occurs and progresses from initial electrons to discharge.

In order to suppress the discharge delay, it is necessary to increase and stabilize the carrier density, but when using high-purity crystalline magnesium oxide as the protective layer, the increase in Fermi level during voltage application becomes significant, Further, since there are few centers for eliminating carriers, a high carrier density can be stably maintained, and as a result, discharge delay is suppressed.
Here, in film formation such as electron beam evaporation and film formation by coating, there is a limit to the improvement in crystallinity, and it is difficult to obtain an effect that suppresses the discharge delay, while the generation conditions are set independently. If the fine crystal 16a can be produced, the crystallinity can be easily improved, and the content ratio of MgO having high crystallinity in the bulk can be increased.

  Even if the fine crystal 16a protrudes slightly from the arrangement region 16r, the visible light transmittance is deteriorated as compared with the structure that does not protrude, but the ratio is small, and the effect of reducing the discharge delay is almost the same. Since they are equivalent, the present invention is not limited to the arrangement region 16r in which the fine particle crystal 16a is arranged, and the PDP 1 may have a configuration in which the fine particle crystal 16a slightly protrudes from the arrangement region 16r.

In the present embodiment, the fine crystal 16a is not disposed at all on the surface of the protective layer 16 other than the disposed region 16r, but the fine crystal coverage is small so as not to affect the translucency. May be smaller than the fine particle crystal 16a disposed in the disposition region 16r, for example, 5%, and disposed in a region other than the disposition region 16r.
In the present embodiment, the printing method is used as a method of applying the volatile liquid containing the fine particle crystals 16a to the surface of the protective layer 16, but the method is not limited to this printing method. An ink jet method may be used.

Even with this method, the magnesium oxide fine particle crystal can be disposed at a low cost on a specific portion of the surface of the protective layer with a high fine particle crystal coverage. Since the dispersion is located on the surface of the protective layer with such a surface density, there is little uneven distribution of the magnesium oxide fine particle crystals.
In this case, a mask may be arranged in a region other than the arrangement region 16r on the surface of the protective layer 16, and the volatile liquid may be ejected toward the entire surface of the protective layer 16. However, when the inkjet ejection position accuracy is high Alternatively, it may be applied by injecting the volatile liquid only to a target location without providing a mask, and the cost can be further reduced.

Furthermore, other methods may be used. For example, a mask may be provided on the surface of the protective layer 16 and the volatile liquid may be sprayed on the surface.
Even with this method, the magnesium oxide fine particle crystal can be disposed at a low cost on a specific portion of the surface of the protective layer with a high fine particle crystal coverage. Since the dispersion is located on the surface of the protective layer with such a surface density, there is little uneven distribution of the magnesium oxide fine particle crystals.

In the present embodiment, the fine particle crystal 16a is arranged at the target position on both sides of the scan electrode 13 side and the sustain electrode 12 side with reference to a straight line that is orthogonal to the address electrode 22 and passes through the center of the discharge cell. However, since the address discharge is generated between the scan electrode 13 and the address electrode 22, the arrangement region 16r of the fine particle crystal 16a may be provided only on the scan electrode side.
In this case, since the arrangement area of the fine crystal is reduced, the translucency can be further improved.

Further, although the protective layer 16 is formed by a thin film process, it may be formed by a thick film process typified by a printing method.
Further, in the PDP 1 of the present embodiment, the main components of the protective layer 16 and the fine crystal 16a are both MgO, but are not limited to MgO, and both are oxides of metals belonging to the same group II as magnesium. I just need it.

Further, in the PDP 1 of the present embodiment, the main component of the protective layer 16 and the main component of the fine crystal 16a are the same, but they may be different.
In that case, both are desirably oxides of metals belonging to Group II.
Further, as described above, the discharge cell corresponds to one of the three primary colors, that is, each of red, green, and blue, and one pixel is displayed by three discharge cells corresponding to each color. For each corresponding discharge cell, the surface density of the fine crystal in the arrangement region may be set.

This is because there is a difference in the emission brightness and the occurrence of discharge delay for each phosphor arranged in each discharge cell, so by determining the surface density of the fine particles for each discharge cell corresponding to each color, light emission This is because finer adjustments can be made to suppress the reduction in efficiency and the discharge delay.
(Modification 1)
In the PDP 1 of the present embodiment, the arrangement region 16r of the fine particle crystal 16a is intensively arranged at the center of the discharge cell. More specifically, the arrangement region 16r of the fine particle crystal 16a is scanned. The transparent electrode 121 of the electrode 13 and the transparent electrode 131 of the sustain electrode 12 are rectangular regions that cover two end portions that are close to each other and a region sandwiched therebetween (hereinafter referred to as a “constriction region”). The arrangement region of the crystal 16a is not limited to this.

FIGS. 6A, 6B, 6C, and 6D are diagrams showing the configuration of the PDP 2 corresponding to the above-described example.
This PDP 2 has the same basic configuration as the PDP 1, only the arrangement position of the fine crystal is different, and the composition of the fine crystal is the same as that of the PDP 1.
More specifically, as shown in FIGS. 6A and 6B, the PDP 2 has a new arrangement area obtained by excluding the stenosis area from the arrangement area 16r of the fine particle crystal 16a in the PDP 1.

In other words, in the transparent electrode 121 of the scanning electrode 13 and the transparent electrode 131 of the sustain electrode 12, the fine particle crystal 116a and the fine particle crystal 116b are arranged at two end portions close to each other. At this time, the respective arrangement areas are referred to as an arrangement area 116ra and an arrangement area 116rb.
As shown in FIGS. 6C and 6D, the fine crystal 116a and the fine crystal 116b are scattered at a uniform surface density in the arrangement region 116ra and the arrangement region 116rb.

When the fine crystal coverage of the fine crystal 116a and the fine crystal 116b is set to the same value as that of PDP1, it is considered that the discharge delay suppression performance of PDP2 is not so different from that of PDP1.
This is because, in the constricted region on the surface of the protective layer 16, as shown in FIG. 3, when the voltage is applied during address discharge, the address field strength distribution is a region that rapidly decreases. Compared to the peak region, the address electric field strength is low, and the potential for initial electron emission is small. Because.

The arrangement method of the fine particle crystals 116a and 116b is the same as the arrangement method of the fine particle crystals 16a. That is, any of a printing method, an ink jet method, and a spray can be used to dispose the fine crystal crystals 116a and 116b on the surface of the protective layer 16.
As described above, the PDP 2 of Modification 1 concentrates the fine particle crystal 116b in a place that originally has a high initial electron emission performance, that is, the end of the transparent electrode 131 of the scan electrode 13, that is, the arrangement region 116rb. In addition, the initial electron emission performance is further improved to suppress discharge delay and reduce the amount of fine particle crystals used per discharge cell, thereby suppressing a significant decrease in light transmission performance and light emission. A decrease in efficiency can be suppressed.

That is, it becomes possible to carry out both the suppression of the decrease in luminous efficiency and the suppression of the discharge delay.
In the PDP 2, no fine crystal is disposed in any region other than the disposition region 116 ra and the disposition region 116 rb, but the fine particle crystal coverage is set so that the translucency is hardly affected. It may be smaller than the particulate crystal coverage of the particulate crystals disposed at 116ra and 116rb, for example, 5%, and disposed in a region other than the disposed region 116ra and the disposed region 116rb.

  In the PDP 2, the arrangement region 116 ra and the arrangement region 116 rb are arranged at target positions on both sides of the scan electrode 13 side and the sustain electrode 12 side with reference to a straight line that is orthogonal to the address electrode 22 and passes through the center of the discharge cell. However, since the address discharge is generated between the scan electrode 13 and the address electrode 22, the fine crystal arrangement area may be limited to the arrangement area 116rb on the scan electrode side.

In the PDP 2 of Modification 1, the main component of the protective layer 16 and the fine crystal crystals 116a and 116b are both MgO, but is not limited to MgO, and both are oxides of metals belonging to the same group II as magnesium. If it is.
Further, in the PDP 1 of the present embodiment, the main component of the protective layer 16 and the main components of the fine particle crystals 116a and 116b are the same, but they may be different. In that case, both are desirably oxides of metals belonging to Group II.

Further, as described in the present embodiment, the surface density of the fine crystal in the arrangement region may be set for each discharge cell corresponding to each color.
This is because there is a difference in the emission brightness and the occurrence of discharge delay for each phosphor arranged in each discharge cell, so by determining the surface density of the fine particles for each discharge cell corresponding to each color, light emission This is because finer adjustments can be made to suppress the reduction in efficiency and the discharge delay.
(Modification 2)
In the PDP 1 of the present embodiment and the PDP 2 of Modification 1 thereof, for example, as shown in FIG. 2A, the length in the Y-axis direction in the region where the fine particle crystals are disposed is that of the transparent electrode 121 and the transparent electrode 131. It was set to be longer than the width (Y-axis direction length).

However, since the address discharge is generated between the scan electrode 13 and the address electrode 22, the address electric field strength is a protective layer facing both the scan electrode 13 and the address electrode 22, as shown in FIG. The surface area becomes high.
That is, it is considered that at the edges in the Y-axis direction of the transparent electrode 121 and the transparent electrode 131, the address electric field strength is low and the potential initial discharge performance is low.

Accordingly, even if the fine crystal is disposed in the region of the protective layer surface facing both the scanning electrode 13 and the address electrode 22 and not disposed at the edge, the effect of suppressing the discharge delay is not much different. It is thought that there is nothing.
FIGS. 7A, 7B, 7C, and 7D are diagrams showing the configuration of the PDP 3 in which the arrangement region of the fine crystal is determined in consideration of the above contents.

This PDP 3 has the same basic configuration and fine particle crystal composition as PDP 1 and PDP 2, but only the arrangement position of the fine particle crystals is different.
That is, in the PDP 3, as shown in FIGS. 7A and 7B, in the transparent electrode 121 of the scanning electrode 13 and the transparent electrode 131 of the sustaining electrode 12, one of the two end portions adjacent to each other and the address electrode 22. It is assumed that the fine crystal 216a and the fine crystal 216b are arranged in the region of the surface of the protective layer 16 facing both of them, that is, in the arrangement region 216ra and the arrangement region 216rb, respectively.

As shown in FIGS. 7C and 7D, the fine crystal 216a and the fine crystal 216b are scattered at a uniform surface density in the arrangement region 216ra and the arrangement region 216rb.
The arrangement method of the fine particle crystals 216a and 216b is the same as the arrangement method of the fine particle crystals 16a. That is, any of a printing method, an ink jet method, and a spray can be used to dispose the fine particle crystals 216a and 216b on the surface of the protective layer 16.

Furthermore, since the area of the arrangement region 216ra and the arrangement region 216rb is greatly reduced as compared with PDP1 and PDP2, the fine particle crystal coverage is 100% in order to secure the amount of fine particle crystals. It is set larger than PDP2.
However, even if the particle crystal coverage was gradually decreased from 100%, no significant discharge delay occurred until 20%.

This is because fine particles have high crystallinity that contributes to suppression of discharge delay and low crystallinity that does not contribute to suppression of discharge delay, and high crystallinity that contributes to suppression of discharge delay. Since the existence probability is very low, an amount of 20% or more is considered necessary to suppress the discharge delay.
The arrangement method of the fine particle crystals 216a and 216b is the same as the arrangement method of the fine particle crystals 16a. That is, any of the above-described printing method, ink jet method, and spray can be used to dispose the fine particle crystals 216a and 216b on the surface of the protective layer 16.

  As described above, the PDP 3 according to Modification 2 originally has a high initial electron emission performance, that is, a region where the end of the transparent electrode 131 of the scan electrode 13 and the address electrode 22 face each other, that is, the arrangement. The fine particle crystals 216b are concentratedly arranged in the region 216rb to further improve the initial electron emission performance, thereby suppressing discharge delay and reducing the amount of fine particle crystals used per discharge cell. A significant decrease in performance can be suppressed, and a decrease in luminous efficiency can be suppressed.

That is, it becomes possible to carry out both the suppression of the decrease in luminous efficiency and the suppression of the discharge delay.
In the PDP 3, no fine crystal is disposed in any region other than the disposition region 216 ra and the disposition region 216 rb, but the fine particle crystal coverage is set so that the translucency is hardly affected. It may be smaller than the fine particle crystal coverage of the fine particles arranged in 216ra and 216rb, for example, 5%, and may be arranged in a region other than the arranged region 216ra and the arranged region 216rb.

  In addition, in the PDP 3, the arrangement area 216 ra and the arrangement area 216 rb are arranged at target positions on both sides of the scan electrode 13 side and the sustain electrode 12 side with reference to a straight line that is orthogonal to the address electrode 22 and passes through the center of the discharge cell. However, since the address discharge is generated between the scanning electrode 13 and the address electrode 22, the arrangement area of the fine crystal may be limited to the arrangement area 216rb on the scanning electrode side.

In the PDP 3 of Modification 2, the main components of the protective layer 16 and the fine crystal 216a and 216b are both MgO, but are not limited to MgO, and both are oxides of metals belonging to the same group II as magnesium. If it is.
Further, in the PDP 3 of Modification 2, the main component of the protective layer 16 and the main components of the fine crystal 216a and 216b are the same, but they may be different. In that case, both are desirably oxides of metals belonging to Group II.

Further, as described in the present embodiment, the surface density of the fine crystal in the arrangement region may be set for each discharge cell corresponding to each color.
Moreover, although the example which reduces the area of the arrangement | positioning area | region of a fine particle crystal gradually with Embodiment 1, the modification 1, and the modification 2 was shown, you may arrange | position a fine particle crystal in forms other than these, For example, even in the setting of the arrangement area listed below, it becomes easier to carry out both the suppression of the reduction in light emission efficiency and the suppression of the discharge delay, compared to the conventional case where the arrangement area of the fine particle crystal is provided on the entire surface of the protective layer.

This is because the arrangement region shown below includes a peak region that is the peak of the address electric field strength, and in other regions than the peak region, fine particle crystals are not disposed, or Since the surface density of the fine particle crystal in the arrangement region is set to be smaller than that of the conventional PDP, the fine particle crystal is concentrated in a region where high initial electron emission performance is latent. However, the initial electron emission performance can be greatly improved, the discharge delay can be efficiently suppressed, and the influence on the decrease in the light transmission performance can be reduced.
(Other examples of arrangement area of fine crystal)
1) A fine particle crystal is disposed on the surface of the protective layer 16 facing the region where the transparent electrode 121 and the transparent electrode 131 are combined.
2) A fine particle crystal is disposed on the surface of the protective layer 16 facing the portion of the address electrode 22 sandwiched between adjacent barrier ribs 25.
3) A combination of the arrangement regions of the respective fine crystal crystals shown in the above examples 1) and 2) is used as a new particle crystal arrangement region.
4) A fine particle crystal is disposed on the surface of the protective layer 16 facing the region where the transparent electrode 121, the transparent electrode 131, and the central portion of the discharge cell sandwiched therebetween are combined.

  The present invention can be applied to display devices used in television receivers, computer monitors, and the like.

It is a disassembled perspective view of PDP in this Embodiment. (A) is a top view of PDP in embodiment of this invention, (b) is sectional drawing, (c) is a fragmentary sectional enlarged view, (d) is a partial planar enlarged view. (A), (b) is a figure which shows the electric field strength distribution on the surface of a protective layer at the time of the voltage application at the time of performing address discharge. It is a figure which shows the relationship between the area ratio of a microcrystal arrangement | positioning area | region when a microcrystal coverage is 30%, and visible light transmittance | permeability. It is a figure which shows the relationship between the area ratio of a microcrystal arrangement | positioning area | region, and a discharge start time ratio. (A) is a top view of PDP in the modification 1 of embodiment of this invention, (b) is sectional drawing, (c) is a fragmentary sectional enlarged view, (d) is a partial planar enlarged view. 5A is a plan view of a PDP according to a second modification of the embodiment of the present invention, FIG. 5B is a cross-sectional view, FIG. 5C is a partial cross-sectional enlarged view, and FIG. It is an enlarged view. It is a disassembled perspective view of the conventional PDP.

Explanation of symbols

1, 2, 3 PDP
DESCRIPTION OF SYMBOLS 10 Front panel 11, 21 Glass substrate 12 Sustain electrode 13 Scan electrode 14 Display electrode pair 15 Dielectric layer 16 Protective layer 16a Fine particle crystal 16r Arrangement area 17a Black stripe 20 Rear panel 22 Address electrode 23 Dielectric layer 24, 25 Partition 26 Phosphor layer 112, 113 Transparent electrode 116a, 116b Fine particle crystal 116ra, 116rb Arrangement region 121, 131 Transparent electrode 122, 132 Bus electrode 216a, 216b Fine particle crystal 216ra, 216rb Arrangement region

Claims (6)

A front plate and a back plate are arranged opposite to each other with a discharge space interposed therebetween, and the front plate has a display electrode pair including a scan electrode and a sustain electrode, a dielectric layer, and a protective layer in order on the side facing the discharge space. The plasma display panel is formed by laminating and arranging the address electrodes intersecting the display electrode pair and the discharge space on the back plate, and forming discharge cells at the intersecting portions,
Fine particles containing metal oxide crystals are disposed on the surface of the protective layer,
A region on the surface of the protective layer facing either the display electrode pair or the address electrode is a first region,
When the region on the surface of the protective layer facing the constricted portion sandwiched between the scan electrode and the sustain electrode is a second region,
Said first and second regions, the than the surface density of the fine particles in the first region and the region other than the second region of the surface of the protective layer, have a surface density greater part of the fine particles, the fine particles The area where the surface density is high is a plasma display panel in which the fineness of the arranged fine particles is higher than the area where the surface density of the fine particles is smaller than the area .   When the region on the surface of the protective layer facing the display electrode pair is a third region, the surface density of the fine particles in the fourth region including the second region and the third region is the protective film. The plasma display panel according to claim 1, wherein the surface density of the fine particles is larger than the surface density of the fine particles in all regions other than the fourth region on the surface. When the region of the surface of the protective layer facing the display electrode pair is a third region,
2. The plasma display panel according to claim 1, wherein the surface density of the fine particles in the third region is larger than the surface density of the fine particles in all regions other than the third region on the surface of the protective film. In each of the scanning electrode and the sustain electrode of the display electrode pair, when the region of the surface of the protective layer facing two end portions that are close to each other is a fifth region,
2. The plasma display panel according to claim 1, wherein the surface density of the fine particles in the fifth region is larger than the surface density of the fine particles in all regions other than the fifth region on the surface of the protective film. In each of the scanning electrode and the sustain electrode of the display electrode pair, when the region of the surface of the protective layer facing two end portions that are close to each other is a fifth region,
The surface density of the fine particles in the sixth region, which is a combination of the fifth region and the second region, is larger than the surface density of the fine particles in all regions other than the sixth region on the surface of the protective film. The plasma display panel as described. There are a plurality of the display electrode pairs,
The scanning electrode and the sustain electrode of the display electrode pair are each composed of a pair of a transparent electrode and a bus electrode,
In the scan electrode and the sustain electrode, the surface density of the fine particles in the seventh region on the surface of the protective layer facing the partial region of each transparent electrode is in all regions other than the seventh region on the surface of the protective film. The plasma display panel according to claim 1, wherein the plasma display panel is larger in surface density than the fine particles.

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