KR20030070338A - Plasma display panel - Google Patents

Abstract

PURPOSE: A plasma display panel is provided to minimize an afterimage by reducing a degradation of phosphor, while allowing for ease of air evacuation. CONSTITUTION: A plasma display panel comprises a barrier rib(56) for spacing an upper substrate(40) and a lower substrate(42); a black matrix(60) arranged on the upper substrate in such a manner that the black matrix corresponds to the barrier rib and permits the upper substrate to be spaced apart from the barrier rib; a pair of sustaining electrodes(44,46) formed on the upper substrate; an address electrode(52) formed in the direction crossing the sustaining electrodes; and a phosphor deposited on the lower substrate and the barrier rib.

Description

Plasma Display Panel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to a plasma display panel capable of minimizing afterimages due to deteriorated phosphor degradation after a window pattern.

Recently, a plasma display panel (hereinafter referred to as "PDP"), which is easy to manufacture a large panel, has attracted attention as a flat panel display device. The PDP normally displays an image by adjusting the discharge period of each pixel according to the digital video data. As such a PDP, an AC type PDP having three electrodes and driven by an AC voltage is typical.

1 is a diagram illustrating a cell structure typically arranged in an alternating-type PDP in a matrix form.

Referring to FIG. 1, a conventional PDP cell includes an upper plate having sustain electrode pairs 14 and 16, an upper dielectric layer 18, and a passivation layer 20 sequentially formed on an upper substrate 10, and a lower substrate 12. A lower plate having an address electrode 22, a lower dielectric layer 24, a partition wall 26, and a phosphor layer 28 sequentially formed thereon is provided. The upper substrate 10 and the lower substrate 12 are spaced in parallel by the partition wall 26. Each of the sustain electrode pairs 14 and 16 has a relatively wide width and a relatively narrow transparent electrode 14A and 16A made of a transparent electrode material (ITO) having a light transmittance of 90% or more, as shown in FIG. Made of metal electrodes 14B and 16B having a width. Here, the transparent electrode material (ITO) has a large resistance value and thus does not transmit power efficiently. Therefore, the resistive components of the transparent electrodes 14A and 16A are formed on the transparent electrodes 14A and 16A by forming metals 14B and 16B having a good conductivity, for example, silver (Ag) or copper (Cu). To compensate. The sustain electrode pairs 14 and 16 are composed of a scan electrode and a sustain electrode. The scan signal for the panel scan and the sustain signal for maintaining the discharge are mainly supplied to the scan electrode 14, and the sustain signal is mainly supplied to the sustain electrode 16. Charges are accumulated in the upper dielectric layer 18 and the lower dielectric layer 24. The protective film 20 prevents damage to the upper dielectric layer 18 by sputtering, thereby increasing the lifetime of the PDP and increasing the emission efficiency of secondary electrons. As the protective film 20, magnesium oxide (MgO) is usually used. The address electrode 22 is formed to cross the sustain electrode pairs 14 and 16. The address electrode 22 is supplied with a data signal for selecting cells to be displayed. The partition wall 26 is formed in parallel with the address electrode 22 to prevent ultraviolet rays generated by the discharge from leaking to adjacent cells. The phosphor layer 28 is applied to the surfaces of the lower dielectric layer 24 and the partition wall 26 to generate visible light of any one of red, green, and blue. Then, an inert gas for gas discharge is injected into the discharge space therein.

The PDP cell is selected by the counter discharge between the address electrode 22 and the scan electrode 14, and then sustains the discharge by the surface discharge between the sustain electrode pairs 14 and 16. In the PDP cell, the fluorescent substance 28 emits light by ultraviolet rays generated during sustain discharge, so that visible light is emitted outside the cell. As a result, the PDP having cells displays an image. In this case, the PDP implements a gray scale required for displaying an image by adjusting the discharge sustain period of the cell, that is, the number of sustain discharges, according to the video data.

The AC surface discharge type PDP is driven by being divided into a plurality of subfields in order to express gray scale of an image, and in each subfield period, gradation display is performed by performing light emission in proportion to the weight of video data. do. For example, when an image is displayed in 256 gray scales using 8-bit video data, one frame display period (for example, 1/60 second = about 16.7 msec) in each discharge cell is divided into eight subfields SF1 to SF1. SF8). Each subfield SF1 to SF8 is further divided into a reset period, an address period, and a sustain period, and 1: 2: 4: 8:... The weight is given at the ratio of 128. Here, the reset period is a period for initializing the discharge cells, the address period is a period during which selective address discharge occurs according to the logic value of the video data, and the sustain period is such that discharge is maintained in the discharge cells in which the address discharge has occurred. It is a period. The reset period and the address period are equally allocated to each subfield period.

In general, impedance has an electrical resistance component. Since the resistance is inversely related to the area, when the area is changed, the electrical resistance component is changed, and consequently, the impedance is changed.

Z = R + jX

Where Z represents impedance and R represents resistance.

The PDP can be regarded as one capacitance having a high impedance in an electric network. Considering this change in impedance, the afterimage of the PDP is considered.

In the PDP, afterimages appear severely due to changes in impedance, degradation of phosphors, or changes in surface properties of the protective film 20. Among the afterimage factors, the biggest factor influencing the PDP afterimage is an erase discharge discharged due to an unstable operation of the PDP. However, erroneous discharges of erase discharges are stabilized to some extent in the operation of the PDP, and the afterimages of the screens are caused by high voltage and high temperature, which are different factors. High voltages or high temperatures during discharge create excess charged particles in the discharge space. The phosphor deteriorates due to the impact of the charged particles thus generated, and an afterimage remains on the screen. This afterimage on the screen appears more clearly after the window pattern. As shown in FIG. 2, the window pattern intensively discharges to a portion 30A of the panel display surface 30 on which an image appears, and then afterimages occur on a portion 30A of the panel display surface when discharge is caused to the entire panel. Appears. For example, when a PDP is used as a monitor, TV, or bulletin board, after-images of companies' logos or important phrases remain, and afterimages remain in place of those logos or important phrases.

In general, when the area of the entire panel is 100, the panel area of the window pattern corresponds to a maximum of four. Since the area of the window pattern is smaller than the area of the entire panel, the current flowing in the window pattern area is small and power consumption is low. In order to maintain constant power consumption before or after the window pattern, an auto power limit (hereinafter referred to as "APL") is used. The APL adjusts the number of sustain discharge pulses supplied to maintain a constant power consumption every frame, regardless of the discharge cells to be turned on. That is, since the power consumption is the average luminance of one frame x the number of sustain discharge pulses of one frame, the total luminance decreases as the area increases, so the number of sustain discharge pulses increases. For example, as shown in Fig. 3, when the relationship between area and magnitude is A <B <C, the relationship between the number of sustain discharge pulses corresponding to each area is set to SUS1> SUS2> SUS3. Since the area of the window pattern is smaller than the area of the entire panel, the number of sustain discharge pulses is larger than the number of sustain discharge pulses supplied to the area of the entire panel in order to consume the same power as that of the entire panel. In terms of power consumed per unit area, it can be seen that power consumed per unit area is consumed by the window pattern area rather than the entire panel area. The large power consumption means that there is a great possibility of accelerating the deterioration of the phosphor, and the luminance difference is not easy to recover depending on how long the window pattern is actually maintained.

The afterimage of such an image is divided into a regressable afterimage and an unreturnable afterimage, which is caused by temperature. A method for preventing afterimage caused by this temperature has been proposed. In other words, by attaching a fan to the PDP to cool the temperature, the rate of change of luminance due to the change in temperature is decreased. The data can be obtained by comparing FIGS. 4A and 4B. 4A is a graph showing a change in luminance according to a temperature change in a panel, and FIG. 4B is a graph showing a change in luminance according to a temperature of a PDP with a fan according to the present invention. As can be seen from the two graphs, the brightness gradually increases as the temperature, which increased sharply after the window pattern, gradually decreases. In both graphs it can be seen that the luminance curve of FIG. 4B returns to the normal luminance of the panel in a shorter time. It can be seen that the time for returning to normal luminance is accelerated by cooling the temperature of the panel having the high temperature by the fan. In other words, it is possible to reduce the afterimage duration due to temperature.

On the other hand, as attention to the irregressive afterimage is concentrated, research on phosphor degradation is being actively conducted.

5A and 5B illustrate a PDP discharge region, in which the discharge of the PDP is mainly formed on the upper substrate. Phosphors applied on the lower substrate are spaced apart from the kitchen area by the height of the partition wall, while the phosphors formed on the partition wall are directly exposed to the kitchen area. Accordingly, when the discharge is started, the phosphor of the region A formed on the partition wall closest to the upper substrate deteriorates quickly. In other words, the phosphor formed in the discharge cell will be damaged by the strong vacuum ultraviolet rays as a whole, but in particular, the phosphor on the partition wall has a photon damage caused by the impact of ions and deposition of the protective film in addition to the phosphor formed on the lower substrate. More damage will result in more damage to the phosphor on the bulkhead.

6 is a graph showing a change in luminance according to discharge time.

Referring to FIG. 6, the luminance decreases as the PDP discharge time elapses, and the first slope L1 indicating the decrease rate of the luminance according to the initial discharge time and the second slope L2 indicating the decrease rate of the luminance after some time have passed. You can see that the size is different. In other words, although the luminance decreases rapidly during the initial discharge, the change in luminance hardly occurs over time. The reason why the luminance suddenly decreases during this initial discharge is because the entire phosphor in the discharge cell is deteriorated, but the phosphor on the partition is damaged in particular. During the initial discharge, the luminance rapidly decreases due to phosphor deterioration on the partition wall, and then gradually decreases as the discharge time passes. The reason why the luminance changes smoothly is that the center of light generated as the phosphor on the partition rapidly deteriorates during the initial discharge is moved to the phosphor formed on the lower substrate. As described above, the luminance cannot be restored again due to the influence of the phosphor formed on the partition wall during the initial discharge.

Accordingly, an aspect of the present invention is to provide a plasma display panel capable of minimizing afterimages due to phosphor degradation after a window pattern.

1 is a view showing a discharge cell of a conventional three-electrode AC surface discharge plasma display panel.

FIG. 2 is a diagram illustrating an afterimage phenomenon after the window pattern of the plasma display panel illustrated in FIG. 1.

3 is a diagram showing the number of sustain pulses supplied according to a discharge area.

4A and 4B are graphs showing a change in luminance according to a change in temperature.

5A and 5B are diagrams showing discharge regions of the plasma display panel shown in FIG.

6 is a view showing a change in luminance with discharge time.

7 is a cross-sectional view illustrating a plasma display panel according to a first embodiment of the present invention.

FIG. 8 is a plan view illustrating the plasma display panel shown in FIG. 7; FIG.

9 illustrates a plasma display panel according to a second embodiment of the present invention.

10 is a perspective view illustrating a plasma display panel according to a third embodiment of the present invention.

FIG. 11 is a plan view of the plasma display panel shown in FIG. 10; FIG.

12A and 12B are cross-sectional views of the plasma display panel shown in FIG. 11 taken along lines A-A 'and B-B'.

<Description of Symbols for Main Parts of Drawings>

10, 40: upper substrate 12, 42: lower substrate

14, 44: scanning electrode 16, 46: sustain electrode

18, 48: upper dielectric layer 20, 50: protective film

22, 52: address electrode 24, 54: lower dielectric layer

26, 56: partition wall 28, 58: phosphor layer

65,75: Black matrix 70: grid bulkhead

In order to achieve the above object, the plasma display panel according to the present invention is a partition for separating the space between the upper substrate and the lower substrate, the black on the upper substrate and the partition and the partition formed between the partition and the upper substrate It is characterized by including a matrix.

The partition wall is characterized in that formed in any one of a stripe shape and a grid.

And a sustain electrode pair formed on the upper substrate, an address electrode formed in a direction crossing the sustain electrode pair, and a phosphor coated on the lower substrate and the partition wall.

The black matrix corresponding to the lattice-shaped partition wall may be formed in a direction parallel to the address electrode.

Each of the sustain electrode pairs includes a transparent electrode and a metal electrode having a width smaller than that of the transparent electrode and compensating for the resistance component of the transparent electrode.

A hole is formed in the transparent electrode corresponding to the partition wall.

The hole is characterized in that formed in the form of any one of a square and a circle.

The height of the black matrix is characterized in that 20 ~ 30㎛.

Other objects and advantages of the present invention in addition to the above object will be apparent from the description of the preferred embodiment of the present invention with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 7 to 12B.

7 and 8, in the PDP according to the first embodiment of the present invention, the black matrix 60 is installed on the upper substrate 40 so as to correspond to the partition wall 56.

According to the present invention, a PDP cell includes an upper plate having sustain electrode pairs 44 and 46, an upper dielectric layer 48, and a passivation layer 50 sequentially formed on the upper substrate 40, and sequentially on the lower substrate 42. A bottom plate having the formed address electrode 52, the lower dielectric layer 54, the partition wall 56, and the phosphor layer 58 is further provided.

The upper substrate 40 and the lower substrate 42 are spaced apart in parallel by the partition wall 56 and the black matrix 60.

The black matrix 60 is formed on the partition wall 56 in a direction parallel to the partition wall 56 to increase the distance between the phosphor 58 and the upper substrate 40. Accordingly, even when an initial discharge occurs around the upper substrate 40, the phosphor 58 formed on the partition wall 56 is spaced apart from the upper substrate 40 by the height of the black matrix 60, thereby minimizing deterioration of the phosphor 58. You can. The total height of the discharge cells is about 150 μm, and the black matrix 60 that contributes to the height of the discharge cells has a height of about 20 to 30 μm.

Each of the sustain electrode pairs 44 and 46 has a relatively wide width and a relatively narrow transparent electrode 44A and 46A made of a transparent electrode material (ITO) having a light transmittance of 90% or more, as shown in FIG. It consists of metal electrodes 44B and 46B which have width. Here, the transparent electrode material (ITO) has a large resistance value and thus does not transmit power efficiently. Accordingly, the resistive components of the transparent electrodes 44A and 46A are formed on the transparent electrodes 44A and 46A by forming metals 44B and 46B having a good conductivity, for example, silver (Ag) or copper (Cu). To compensate. The sustain electrode pairs 44 and 46 are composed of a scan electrode and a sustain electrode. The scan signal for the panel scan and the sustain signal for maintaining the discharge are mainly supplied to the scan electrode 44, and the sustain signal is mainly supplied to the sustain electrode 46. Charges are accumulated in the upper dielectric layer 48 and the lower dielectric layer 54. The black matrix 60 is applied on the upper dielectric layer 48 in the direction of the partition wall 56. The passivation layer 50 prevents damage to the upper dielectric layer 48 by sputtering, thereby increasing the lifetime of the PDP and increasing the emission efficiency of secondary electrons. As the protective film 50, magnesium oxide (MgO) is usually used. The address electrode 52 is formed to cross the sustain electrode pairs 44 and 46. The address electrode 52 is supplied with a data signal for selecting cells to be displayed. The partition wall 56 is formed in parallel with the address electrode 52 to prevent ultraviolet rays generated by the discharge from leaking to adjacent cells. The phosphor layer 58 is applied to the surfaces of the lower dielectric layer 54 and the partition wall 56 to generate visible light of any one of red, green, and blue. Then, an inert gas for gas discharge is injected into the discharge space therein.

7 and 8, in the PDP according to the first embodiment of the present invention, the black matrix 60 is disposed on the upper dielectric layer 48 of the upper substrate 40 to correspond to the partition wall 56.

According to the present invention, a PDP cell includes an upper plate having sustain electrode pairs 44 and 46, an upper dielectric layer 48, and a passivation layer 50 sequentially formed on the upper substrate 40, and sequentially on the lower substrate 42. A bottom plate having the formed address electrode 52, the lower dielectric layer 54, the partition wall 56, and the phosphor layer 58 is further provided.

The upper substrate 40 and the lower substrate 42 are spaced apart in parallel by the partition wall 56 and the black matrix 60.

The black matrix 60 is formed on the partition wall 56 in a direction parallel to the partition wall 56 to increase the distance between the phosphor 58 and the upper substrate 40. Accordingly, even when an initial discharge occurs around the upper substrate 40, the phosphor 58 formed on the partition wall 56 is spaced apart from the upper substrate 40 by the height of the black matrix 60, thereby minimizing deterioration of the phosphor 58. You can. The total height of the discharge cells is about 150 μm, and the height h1 of the black matrix 60 that contributes to the height of the discharge cells has a height of about 20 to 30 μm.

Each of the sustain electrode pairs 44 and 46 has a relatively wide width and a relatively narrow transparent electrode 44A and 46A made of a transparent electrode material (ITO) having a light transmittance of 90% or more, as shown in FIG. It consists of metal electrodes 44B and 46B which have width. Here, the transparent electrode material (ITO) has a large resistance value and thus does not transmit power efficiently. Accordingly, the resistive components of the transparent electrodes 44A and 46A are formed on the transparent electrodes 44A and 46A by forming metals 44B and 46B having a good conductivity, for example, silver (Ag) or copper (Cu). To compensate. The sustain electrode pairs 44 and 46 are composed of a scan electrode and a sustain electrode. The scan signal for the panel scan and the sustain signal for maintaining the discharge are mainly supplied to the scan electrode 44, and the sustain signal is mainly supplied to the sustain electrode 46. Charges are accumulated in the upper dielectric layer 48 and the lower dielectric layer 54. The black matrix 60 is applied on the upper dielectric layer 48 in the direction of the partition wall 56. The passivation layer 50 prevents damage to the upper dielectric layer 48 by sputtering, thereby increasing the lifetime of the PDP and increasing the emission efficiency of secondary electrons. As the protective film 50, magnesium oxide (MgO) is usually used. The address electrode 52 is formed to cross the sustain electrode pairs 44 and 46. The address electrode 52 is supplied with a data signal for selecting cells to be displayed. The partition wall 56 is formed in parallel with the address electrode 52 to prevent ultraviolet rays generated by the discharge from leaking to adjacent cells. The phosphor layer 58 is applied to the surfaces of the lower dielectric layer 54 and the partition wall 56 to generate visible light of any one of red, green, and blue. Then, an inert gas for gas discharge is injected into the discharge space therein.

Referring to FIG. 9, the PDP according to the second embodiment of the present invention may pattern the transparent electrodes 44B and 46B in a region corresponding to the partition wall 56 to weaken the electric field around the partition wall 56.

Each of the sustain electrode pairs 44 and 46 includes a transparent electrode 44A and 46A having a relatively wide width and a hole 65 and a metal electrode 44B and 46B having a relatively narrow width. Here, the transparent electrodes 44A and 46A are made of transparent electrode material (ITO), which does not transmit power efficiently because the transparent material has a large resistance value. Accordingly, the resistive components of the transparent electrodes 44A and 46A are formed on the transparent electrodes 44A and 46A by forming metals 44B and 46B having a good conductivity, for example, silver (Ag) or copper (Cu). To compensate.

The partition wall 56 is formed in parallel with the sustain electrode pairs 44 and 46 to prevent ultraviolet rays generated by the discharge from leaking into adjacent cells.

The phosphor layer 58 is applied to the lower dielectric layer of the lower substrate and the surfaces of the partition walls 56 to generate visible light of any one of red, green, and blue.

Holes 65 are formed in the transparent electrodes 44A and 46B of the sustain electrode pairs 44 and 46 and overlap with the partition wall 56. The hole 65 may have a shape such as a rectangle or a circle. The hole 65 weakens the electric field around the partition wall 56, and the electric field becomes stronger toward the center of the discharge cell. Accordingly, strong discharge occurs toward the center of the discharge cell, and weak discharge occurs around the partition wall 56. Since the electric field around the barrier 56 is weakened, it is possible to minimize the degradation of the phosphor layer 58 formed on the barrier rib 56 during the initial discharge.

Referring to FIG. 10, the PDP according to the third embodiment of the present invention forms the matrix 75 in a direction parallel to the address electrode 52 so as to correspond to the lattice partition wall 70.

Hereinafter, the same description as in the first embodiment will be omitted.

The grid-shaped partition wall 70 is formed in a rectangular structure surrounding the slopes of the discharge cells to prevent optical interference between the discharge cells.

The black matrix 75 is formed on the passivation layer 50 of the upper substrate 40 to correspond to the lattice-shaped partition wall 70 and to be parallel to the address electrode 52. The black matrix 75 is formed on the lattice-shaped partition wall 70 to increase the distance between the phosphor 58 and the upper substrate 40. Accordingly, even if an initial discharge occurs around the upper substrate 40, the phosphor formed on the grid-shaped partition wall 70 is spaced apart from the upper substrate 40 by the height of the black matrix 75, thereby minimizing phosphor degradation. Furthermore, since the black matrix 75 is formed in a stripe shape in one direction, it is possible to form an exhaust path in the discharge cells closed by the lattice-shaped partition wall 70. The total height of the discharge cells is about 150 μm, and the black matrix 75 that contributes to the height of the discharge cells has a height of about 20 to 30 μm.

As described above, the plasma display panel according to the present invention is provided with a black matrix on the partition wall spaced apart between the upper substrate and the lower substrate. Accordingly, the plasma display panel according to the present invention can increase the distance between the phosphor on the partition and the initial discharge space that are easily exposed to the initial discharge. Therefore, deterioration of the phosphor located on the partition wall which causes the afterimage of the screen can be minimized, thereby increasing the possibility of return of luminance or color balance. In addition, the plasma display panel according to the present invention can reduce the deterioration of the phosphor and reduce the contrast due to the increase in luminance by providing the black matrix in a predetermined direction so as to correspond to the lattice partition. Furthermore, in the plasma display panel according to the present invention, a gap is formed between the partition wall and the upper substrate by installing a black matrix on the grid-shaped partition wall, thereby facilitating the exhaust.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (8)

A partition wall for separating the upper substrate from the lower substrate, And a black matrix formed on the upper substrate so as to correspond to the barrier rib and to be spaced apart from the barrier rib and the upper substrate. The method of claim 1, And the barrier rib is formed in one of a stripe type and a lattice type. The method of claim 1, A sustain electrode pair formed on the upper substrate, An address electrode formed in a direction crossing the sustain electrode pair; And a phosphor coated on the lower substrate and the partition wall. The method according to any one of claims 2 and 3, And the black matrix corresponding to the lattice-shaped partition wall is formed in a direction parallel to the address electrode. The method of claim 1, Each of the sustain electrode pairs includes a transparent electrode; And a metal electrode having a width smaller than that of the transparent electrode and compensating for the resistive component of the transparent electrode. The method of claim 5, And a hole is formed in the transparent electrode corresponding to the partition wall. The method of claim 6, The hole is a plasma display panel, characterized in that formed in the form of any one of a rectangle and a circle. The method of claim 1, The height of the black matrix is a plasma display panel, characterized in that 20 ~ 30㎛.