KR100708847B1 - Plasma display panel - Google Patents

Abstract

The present invention relates to a plasma display panel, comprising: a first substrate and a second substrate disposed substantially parallel to each other at arbitrary intervals; A plurality of address electrodes formed on the first substrate; A first dielectric layer formed over the first substrate while covering the address electrodes; A plurality of partition walls provided at a predetermined height with the first dielectric layer and disposed in a space between the first substrate and the second substrate to form a discharge space partitioned at predetermined intervals; A fluorescent layer formed in the discharge space; A plurality of discharge sustain electrodes disposed on one surface of the second substrate opposite to the first substrate in a direction crossing the address electrodes; A second dielectric layer formed over the second substrate while covering the discharge sustain electrodes; And a protective film formed covering the second dielectric layer, wherein the protective film contains MgO and Ca, wherein Ca is present in the protective film such that a concentration gradient increases in the thickness direction in the protective film surface layer in contact with the discharge space. to provide.

Plasma display panel of the present invention increases the content of Ca in the depth direction from the sputtered surface when forming the MgO protective film to a certain range, it is possible to implement a stable discharge characteristics without loss of secondary electron emission characteristics, and also to maintain a constant content of Ca By adjusting to the range, the fall of a lifetime characteristic can be prevented.

Plasma, Display, Protective Film, Ca, Depth, A-Y Discharge

Description

Plasma Display Panel {PLASMA DISPLAY PANEL}

1 is a partially exploded perspective view showing an example of a plasma display panel of the present invention.

2 is a perspective view of an upper substrate of a plasma display panel according to an embodiment of the present invention.

3 is a graph showing the content of Ca in the depth direction according to the film thickness in the MgO protective film of the plasma display panel according to an embodiment of the present invention.

Figure 4 is a graph showing the formulated content of Ca according to the film thickness included in the MgO protective film of the present invention.

5 is a graph showing the life characteristics of the plasma display panels of Examples 1 and 2 and Comparative Examples 1 and 2 according to the present invention.

6 is a graph showing discharge characteristics of the plasma display panels of Examples 1 and 2 and Comparative Examples 1 and 2 according to the present invention.

The present invention relates to a plasma display panel, and more particularly, to increase the content of Ca in the thickness direction in the surface layer in contact with the discharge space of the protective film, and to improve the discharge characteristics and the life characteristics. It relates to a plasma display panel comprising.

Plasma display panel (PDP) is a display device that realizes an image by exciting phosphors by vacuum ultraviolet rays caused by gas discharge in a discharge cell. It is attracting attention as a thin display device.

A plasma display panel (PDP) is a device that displays characters or graphics using light emitted from plasma generated during gas discharge. The plasma display panel (PDP) applies a predetermined voltage to two electrodes installed in the discharge space of the plasma display panel. Plasma discharge is caused to occur between them, and the phosphor layer formed in a predetermined pattern is excited by ultraviolet rays generated during the plasma discharge to form an image.

Such plasma displays are classified into AC type, DC type, and hybrid type, among which AC type is most widely used.

The AC plasma display device has a basic structure in which electrodes are alternately arranged on two substrates filled with discharge gas and partitioned into partitions. A layer is formed.

The electrodes, barrier ribs, dielectric layers, etc. are generally formed in a printing process in consideration of economical aspects, so that a thick film is formed, and thus the film formation state is considerably poorer than a thin film process.

Therefore, the sputtering of the electrons and ions generated by the discharge damages the dielectric layer and the lower electrode, thereby shortening the life of the AC plasma display device.

In order to solve this problem, a protective film is formed on the dielectric layer with a thickness of about several hundred nm for the purpose of reducing the influence of ion bombardment during discharge.

As a protective film material of the said PDP, MgO material is manufactured and used for the sintered compact. The use of MgO as a sintered compact is because quantitative doping of specific components for improving discharge characteristics is possible and can be freely controlled within its solid solution limit. The protective film made of MgO lowers the discharge voltage and protects the dielectric layer by sputtering, thereby extending the life of the AC plasma display device. Therefore, research on the doping of specific components for high resolution plasma display device to maximize the advantages compared to the single crystal material has been actively conducted.

However, the protective film is greatly changed in characteristics according to film formation conditions such as heat deposition, so that it is difficult to maintain a constant display quality. The passivation layer is likely to generate black noise due to an address discharge delay, that is, a discharge miss, a phenomenon in which a cell selected to emit light does not emit light. The occurrence of such black noise can easily occur at the boundary between the light emitting area and the non-light emitting area in the screen but appears at a certain place, and the discharge miss is due to its low intensity when there is no address discharge or even scanning discharge is performed. Caused by

Therefore, research into a method of adding a dopant capable of improving the characteristics of the plasma display panel has been actively conducted.

The present invention is to solve the above-mentioned conventional problems, an object of the present invention includes a protective film in which the MgO and the Ca content in the depth direction changes in the thickness of the surface layer in contact with the discharge space, the loss of secondary electron emission characteristics The present invention is to provide a plasma display panel having stable discharge characteristics and excellent life characteristics, thereby improving display quality.

Another object of the present invention is to change the content of Ca in the thickness direction of the surface layer in contact with the discharge space in the plasma display panel (PDP) protective film, thereby preventing the discharge state in a particular cell such that each cell to be turned on does not turn on. It is to provide a plasma display panel that can control and improve display quality.

In order to achieve the above object, the present invention,

A first substrate and a second substrate disposed substantially parallel at any interval;

A plurality of address electrodes formed on the first substrate;

A first dielectric layer formed over the first substrate while covering the address electrodes;

A plurality of partition walls provided to the first dielectric layer at a predetermined height and disposed in a space between the first substrate and the second substrate to form a discharge space partitioned at predetermined intervals;

A fluorescent layer formed in the discharge space;

A plurality of discharge sustain electrodes disposed on one surface of the second substrate opposite to the first substrate in a direction crossing the address electrodes;

A second dielectric layer formed over the second substrate while covering the discharge sustain electrodes; And

It is formed covering the second dielectric layer, and comprises a protective film containing MgO and Ca,

In the passivation layer, Ca is provided to have a concentration gradient that increases in the thickness direction in the passivation layer surface layer in contact with the discharge space.

Hereinafter, the present invention will be described in detail.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective film of a plasma display panel capable of improving display quality by controlling black noise generation due to an address miss in a high definition plasma display device so that stable driving is performed.

In addition, the present invention is a general AC-PDP in which the surface of the prepared MgO protective film is sputtered by plasma discharge (especially AY discharge: this occurs between the upper and lower plates, causing sputtering of the protective film). The protective film layer sputtered by ion bombardment has a thickness change.

The protective layer covers the surface of the dielectric layer in the plasma display panel to protect the dielectric layer from ion bombardment of the discharge gas during the discharge period.

The protective film of this invention contains magnesium oxide (MgO) as a main component as a base material, and contains Ca as a specific dopant component here.

In the present invention, the content of Ca is characterized by a change in the film thickness direction from the surface in contact with the discharge space. It is formed to have a concentration gradient that increases the content of Ca in the film thickness direction from the surface layer in contact with the discharge space. In the protective film of the present invention, Ca is preferably present in a concentration gradient as shown in Equation 1 below.

(Equation 1)

Y = (a / 50) X + b

Wherein Y is the content of Ca, X is the film thickness, a is in the range of 11 to 14, preferably 11.5 to 13.8, and b is in the range of 145 to 160. In addition, the unit of Y is ppm and the unit of X is nm.

More preferably, the content of Ca is included in an amount of 150 to 400 ppm, more preferably 150 to 250 ppm, based on the total weight of the MgO protective film. When the content of Ca is less than 150 ppm or more than 400 ppm, there is a fear of causing a decrease in response speed and causing a discharge miss.

It is preferable that the thickness of the protective film of this invention is 500 nm-900 nm. In addition, the MgO protective film of the present invention is formed as a thin thin film having an electron emission characteristic, the transmittance of the MgO protective film is 90% or more, preferably 90% to 97%, preferably has a refractive index of 1.45 ~ 1.74 at 640nm. Do.

The protective layer uses MgO having a sputtering property and a large secondary electron emission coefficient as a base material, and the MgO material may be in the form of a single crystal or a sintered body, but it is preferable to use a polycrystal manufactured by the sintering method. In contrast, the dopant can be employed in a fixed amount, which is preferable. The present invention quantitatively adds the above dopant elements in the production of sintered MgO material or in the production of raw materials to produce a MgO protective film by vapor deposition using plasma.

The protective film can be formed by a vapor deposition method or a thick film printing method using a paste. The film formed by the evaporation method is preferable because it is resistant to sputtering by ion bombardment, and can reduce the discharge sustain voltage and the discharge start voltage due to secondary electron emission. The protective film is sputtering, electron beam deposition, ion beam assisted deposition, ion plating, magnetron sputtering, CVD chemical vapor deposition, physical vapor deposition, plasma enhanced chemical vapor deposition, thermal It can form using a vapor deposition method, a vacuum vapor deposition method, etc. Among them, membranes having particularly excellent properties can be obtained from membranes prepared by the ion plating method.

In addition, the MgO protective film employed in AC-PDP generally has a columnar crystalline structure, which may be different depending on the growth direction, but the columnar crystal structure has a discharge characteristic or resistance compared to amorphous. It is excellent in sputterability. Therefore, in the present invention, a protective film prepared by inducing crystal growth is used.

Plasma display panel of the present invention is to change the Ca content as described above to form a first protective film, and a second protective film containing at least one element from the group consisting of Si, Al, Fe, Cr, and Na as a dopant It may be formed. The dopants included in the second passivation layer may also be formed to increase in a thickness direction in the surface layer in contact with the discharge space.

Preferably, a second passivation layer including a first passivation layer having a Ca content changed and at least one dopant selected from the group consisting of Si, Al, Fe, Cr, and Na is formed on a surface of the first passivation layer, The first protective film and the second protective film preferably have a columnar crystal structure and are protective films sputtered by ion bombardment caused by AY discharge.

In the sputtered by the AY discharge, the protective film of the present invention is changed to have a concentration gradient in which the content of Ca increases in the film thickness direction from the surface layer in contact with the discharge space, so that there is no loss of the secondary electron emission characteristics of the surface layer, thereby ensuring stable discharge characteristics. Can be obtained, and the degradation of life characteristics can be prevented due to the maintenance of constant Ca content.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the plasma display panel of the present invention having the protective film.

1 is a partially exploded perspective view showing an example of a plasma display panel of the present invention, the contents of the present invention is not limited to the structure of FIG. Referring to the drawings, in the plasma display panel of the present invention, address electrodes 3 are formed in one direction (Y direction in the drawing) on the first substrate 1, and the first electrodes cover the address electrodes 3. The dielectric layer 5 is formed on the front surface of the substrate 1. The partition wall 7 is formed on the dielectric layer 5, and red (R), green (G), and blue (B) are formed on the bottom surface 5a and the partition side surface 7a of the discharge cell between each partition wall 7. Phosphor layer 9 is located. One surface of the second substrate 11 opposite to the first substrate 1 includes a pair of transparent electrodes 13a and bus electrodes 13b along a direction orthogonal to the address electrode 3 (X direction in the drawing). The discharge sustain electrodes 13 are formed, and the transparent dielectric layer 15 and the passivation layer 17 are disposed on the entire second substrate 11 while covering the discharge sustain electrodes 13. As a result, the intersection of the address electrode 3 and the discharge sustain electrode 13 constitutes a discharge cell.

With this configuration, the address discharge is applied by applying the address voltage Va between the address electrode 3 and any one of the discharge sustaining electrodes 13, and the sustain voltage Vs is again generated between the pair of discharge sustaining electrodes 13. ), The vacuum ultraviolet rays generated during the sustain discharge excite the phosphor layer 9 to emit visible light through the transparent front substrate 11.

FIG. 2 illustrates only a second substrate (upper substrate) of the plasma display panel including the passivation layer according to an embodiment of the present invention. In FIG. 2, for convenience of understanding, the upper substrate of the plasma display panel according to an embodiment of the present invention is turned upside down by 180 degrees.

Referring to FIG. 2, a plurality of discharge holding electrodes 13, a second dielectric layer 15, and a protective film 17 including MgO and Ca of the present invention are sequentially formed on the second substrate 11. That is, a plurality of discharge sustain electrodes 13 are formed on one surface of the second substrate in a direction crossing the address electrodes 3, and cover the discharge sustain electrodes 13. The second dielectric layer 15 is formed on the front surface of the substrate. A passivation layer 17 including MgO and Ca is formed on the second dielectric layer 15 while covering the second dielectric layer 15.

Plasma display panel The plasma display panel is manufactured by applying the frit to the edges of the first and second substrates, and sealing both substrates and injecting a discharge gas such as Ne or Xe.

In the plasma display panel according to the embodiment of the present invention manufactured as described above, a driving voltage is applied from the electrodes to generate an address discharge between the electrodes, thereby forming wall charges in the dielectric layer, and in the discharge cells selected by the address discharge. A sustain discharge is caused between these electrodes by an alternating current signal supplied to the pair of electrodes formed on the second substrate with stirring arc. Accordingly, the discharge gas charged in the discharge space forming the discharge cell is excited and transitioned to generate ultraviolet light, and to generate an image while generating visible light by excitation of the phosphor by the ultraviolet light.

In addition, as shown in FIG. 2, in the plasma display panel according to the exemplary embodiment of the present invention, a plurality of electrodes cross each other to form pixels and gather together to form a display area inside the passivation layer forming area, and a non-display area at the periphery thereof. To form. A plurality of electrodes 13 formed on the substrate 11 has a terminal portion drawn out to the left and right of the dielectric layer 15 so as to be connected to a flexible printed circuit (FPC) (not shown).

The manufacturing method of the plasma display panel of the present invention having the above-described structure is well known in the art, and can be fully understood by those skilled in the art, and thus the detailed description thereof will be omitted.

Hereinafter, preferred examples and comparative examples of the present invention are described. However, the following examples are only preferred embodiments of the present invention and the present invention is not limited by the following examples.

(Examples 1 to 3)

A discharge sustaining electrode was formed in a stripe shape in a conventional manner using an indium tin oxide conductor material on an upper substrate made of soda lime glass.

Subsequently, a paste of lead-based glass was coated over the entire surface of the upper substrate on which the discharge sustaining electrode was formed and baked to form a second dielectric layer.

Thereafter, a protective film including MgO and Ca was prepared on the second dielectric layer by using a sputtering method to prepare an upper panel. At this time, the content of Ca was increased from 150 to 400 ppm from the surface, as shown in Figure 2 and Table 1 (unit: ppm). A graph of the increase of the Ca content according to the thickness of the protective film is shown in FIG. 3.

TABLE 1

Example 1 Example 2 Example 3 0 nm 150 157 167 50 nm 174 162 183 100 nm 192 183 199 150 nm 203 215 225 200 nm 216 223 238 250 nm 229 241 242 300 nm 235 246 251 350 nm 239 253 268 400 nm 247 268 274 450 nm 261 279 295 500 nm 265 284 298 550 nm 271 288 305 600 nm 288 293 345 650 nm 300 315 358 700 nm 343 337 362 750 nm 354 348 384 800 nm 376 352 402

(Example 4)

The optimum slope of the Ca content used in Examples 1 to 3 is formulated and shown in FIG. 4. Regarding the Ca content calculated by FIG. 4, the optimum contents of the surface layer and the base layer are shown in Table 2 (unit: ppm). The surface layer means a surface (0 nm) in contact with the discharge space, and the base layer means a surface in contact with the dielectric surface.

TABLE 2

division Average Standard Deviation (StDeV) Surface layer (0 nm) 158.00 8.54 Base layer (800 nm) 376.7 25.0

(Comparative Example 1)

The same procedure as in Example 1 was carried out except that Ca was not included.

(Comparative Example 2)

The same process as in Example 1 was carried out except that Ca was deposited to have a constant content throughout the protective film.

Experimental Example

The MgO protective films prepared according to Examples 1 and 2 and Comparative Examples 1 and 2 were tested for life and gamma characteristics, and the results are shown in FIGS. 5 and 3, 6, and 4, respectively.

TABLE 3

 division 0 100 200 300 400 500 750 1000 1500 2000 Comparative Example 1 100% 97% 95% 94% 93% 93% 90% 88% 87% 85% Comparative Example 2 100% 97% 95% 94% 93% 93% 92% 88% 86% 83% Example 1 100% 98% 96% 94% 93% 93% 93% 90% 90% 89% Example 2 100% 97% 95% 95% 93% 93% 92% 91% 90% 88%

TABLE 4

 division 100 110 120 130 140 150 160 170 180 190 200 Comparative Example 1 0.033 0.039 0.053 0.057 0.059 0.062 0.075 0.075 0.077 0.083 0.087 Comparative Example 2 0.034 0.041 0.052 0.055 0.069 0.071 0.079 0.076 0.075 0.081 0.082 Example 1 0.035 0.042 0.063 0.074 0.082 0.084 0.089 0.091 0.093 0.097 0.092 Example 2 0.034 0.046 0.061 0.072 0.084 0.088 0.091 0.093 0.098 0.095 0.097

From the above results, it can be seen that in Examples 1 and 2 of the present invention, by increasing the amount of Ca from the surface in the depth direction when forming the MgO protective film, the life characteristics and discharge characteristics are superior to Comparative Examples 1 and 2.

As described above, the plasma display panel of the present invention has a concentration gradient that increases in the thickness direction in the protective film surface layer in contact with the discharge space when MgO protective film is formed, thereby providing excellent sputter performance, in particular, improving electron emission characteristics and lifetime characteristics. In this way, the display quality can be improved.

Claims (9)

A first substrate and a second substrate disposed in parallel at any interval, A plurality of address electrodes formed on the first substrate, A first dielectric layer formed over the first substrate while covering the address electrodes; A plurality of partition walls provided at a predetermined height with the first dielectric layer and disposed in a space between the first substrate and the second substrate to form a discharge space partitioned at a predetermined interval; A fluorescent layer formed in the discharge space, A plurality of discharge sustain electrodes disposed on one surface of the second substrate opposite to the first substrate in a direction crossing the address electrodes; A second dielectric layer formed over the second substrate while covering the discharge sustain electrodes; and It is formed covering the second dielectric layer, and comprises a protective film containing MgO and Ca, Ca in the protective film is present to have a concentration gradient that increases in the thickness direction in the protective film surface layer in contact with the discharge space Plasma display panel. The plasma display panel of claim 1, wherein a relationship between the Ca content and the film thickness is represented by the following Equation 1. (Equation 1) Y = (a / 50) X + b Wherein Y is the content of Ca (ppm), X is the film thickness (nm), a is in the range of 11 to 14 and b is in the range of 145 to 160. The plasma display panel of claim 2, wherein the content of Ca is 150 to 400 ppm based on the total weight of the MgO protective film. The plasma display panel of claim 3, wherein the Ca content is included in an amount of 150 to 250 ppm based on the total weight of the MgO protective film. The method of claim 1, The plasma display panel has a thickness of 500 to 900 nm. The method of claim 1, The protective film further comprises a second protective film layer comprising at least one element selected from the group consisting of Si, Al, Fe, Cr, and Na. The method of claim 1, The protective film has a columnar crystal structure. The method of claim 1, The protective film is formed by the ion bombardment sputtered by the A-Y discharge plasma display panel. The plasma display panel of claim 1, wherein the MgO is a polycrystal manufactured by a sintering method.

Images