KR100266209B1 - Apparatus and method for forming wall electric charge of plasma display panel - Google Patents

Abstract

PURPOSE: An apparatus and a method for forming a wall charge of a plasma display panel are provided to improve the contrast by forming a wall charge in an inside of a cell. CONSTITUTION: A plasma display panel is formed with an upper glass plate(30), a lower glass plate(40), a barrier rib(38), a holding electrode(32b), a dielectric layer(34), a protective layer(36), and a fluorescent material(44). An apparatus for forming a wall charge comprises an address electrode(42), a scanning/holding electrode(32a), and an auxiliary electrode(46). The address electrode(42) is arranged between the lower glass plates(40) and the fluorescent material(44). The scanning/holding electrode(32a) is formed on the upper glass plate(30). The auxiliary electrode(46) is formed on the protective layer(36).

Description

Apparatus for Forming Wall Charge of Plasma Display Panel and Method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display apparatus, and more particularly, to a wall charge forming apparatus and a method for generating wall charges inside a cell by generating a slight discharge in a reset period.

Recently, research into plasma display panels (hereinafter referred to as PDPs) with the possibility of accessing cathode ray tubes (CRTs) having high quality and low power consumption as flat panel display devices that pursue thinning, large size, and high image quality is actively conducted. It is becoming. This PDP is a display device that displays images by using a gas discharge phenomenon, and has the advantage of making a large area that other flat panel display devices, such as LCD (Lyquid Crystal Display) and EL (Electro Luminescence) display modules, cannot have. . In addition, PDPs have been widely spotlighted compared to other flat panel display devices in terms of low power consumption by using discharge selectivity due to nonlinearity, simplicity of process according to a simple structure, and low cost by using most glass materials.

Such PDPs are largely classified into AC and DC methods. AC type PDP is characterized by applying an alternating voltage between two electrodes with a dielectric interposed therebetween to discharge every half cycle, and DC type PDP is characterized in that it discharges by directly applying a DC voltage between electrodes. Here, the AC-type PDP is a surface discharge type using three electrodes and has a merit that low power driving is possible because a dielectric having a memory effect is used as charge accumulation. On the other hand, the direct current type PDP is a counter-discharge type, which applies a voltage directly between the electrodes, so that the luminous efficiency is good. However, the PDP of the direct current type PDP has a short lifespan by exposing the electrodes to the discharge space.

1 is a cross-sectional view showing a structure of a pixel cell of an AC (AC) type PDP. In general, a PDP cell is composed of three subcells corresponding to red (R), green (G), and blue (B). have.

Each of the subcells of the PDP shown in FIG. 1 is positioned at a predetermined distance from the lower pane 20 so as to face the upper pane 10 as the display surface of the image, and the upper pane 10 and the lower pane 20 are located. The partition 18 is formed in between to provide a discharge space in the cell. On the top glass 10, two sustain electrodes, that is, the scan / hold electrode 12a and the sustain electrode 12b, are arranged side by side, and on the top glass 10 on which the sustain electrodes 12a and 12b are disposed. The dielectric layer 14 is formed flat. A protective film 16, for example, a magnesium oxide (MgO) film, is formed on the dielectric layer 14 to prevent damage to the dielectric layer 14 from sputtering of plasma particles due to discharge between the two electrodes 12a and 12b. The address electrode 22 is disposed on the lower glass 20, and on the lower glass 20 where the address electrode 22 is disposed, the visible light of red, green, and blue is emitted by ultraviolet (UV) light when the cell is discharged. One of the red, green, and blue phosphors 24 is applied to include a part of the partition wall 18. An inert gas such as neon (Ne), helium (He), xenium (Xe), and the like is enclosed in the internal space of the PDP cell configured as described above. These gases are ionized into electrons and ions by a counter discharge between the scan / hold electrode 12a and the address electrode 22, that is, by a scan discharge, and become a plasma state. Phosphors are excited by the ultraviolet rays and emit light.

PDPs having such a configuration basically operate by scanning discharge and sustain discharge. Here, the scanning discharge is to determine the on / off of the cell, which forms a lot of wall charge therein for the sustain discharge of the cell to be turned on. The wall charges formed inside the lit cells are used during the sustain discharge to prevent erroneous discharge of each cell and to perform a reliable sustain discharge. Here, the generation of the wall charge is determined by the scanning discharge by applying a high voltage between the scan / hold electrode 12a formed on the upper glass and the address electrode 22 formed on the lower glass. In other words, the generation of wall charge is determined by the voltage supplied between the scan / hold electrode and the address electrode. In general, when a large number of wall charges are formed inside the cell due to the scanning discharge, the voltage driving during the sustain discharge is also reduced, which leads to a reduction in power consumption and a certain sustain discharge caused by the wall charge. There are several advantages such as no. On the other hand, when the wall charge formed inside the cell is insufficient, the operation rate decreases, such as an erroneous discharge occurs, resulting in unstable operation, resulting in poor image quality or inoperability. The sustain discharge is caused by a sustain pulse applied between the scan / sustain electrode 12a and the sustain electrode 12b, and the image is displayed by using wall charges formed by the scan discharge. It depends on the function.

2 illustrates a driving waveform of an AC PDP, and a general PDP driving waveform may be largely divided into a reset period, an address period, and a sustain period. Here, the reset period is a period for slightly remaining wall charges inside the entire cell for stable operation of the cell, and the interval between syringes accumulates wall charges such that the next sustain discharge is possible for the pixels to be lit. It is a period to let. Finally, the sustain period is a period for generating sustain discharge only for the cells in which the scan discharge has occurred. The PDP determines the gradation based on the number of discharges corresponding to the number of sustain pulses applied in this sustain period, and displays an image.

Referring to FIG. 2, first, a high voltage is applied between the two sustain electrodes 12 on the top glass 10, that is, the scan / sustain electrode 12a and the sustain electrode 12b in the reset period, so that the wall of the dielectric layer 14 is removed. To form a charge. Once erased, most wall charges are neutralized. At this time, in the reset period, as shown in FIG. 2, a plurality of discharges are generated between the scan / sustain electrode 12a and the sustain electrode 12b, thereby maintaining uniform wall charges inside the cell, thereby performing stable operation. To make it possible. Subsequently, scan discharge is performed by the image data pulse applied to the address electrode 22 and the scan pulse applied to the scan / hold electrode 12a between the syringes to form wall charges in the cells to be lit. Then, the sustain discharge is performed by the sustain pulse applied between the scan / sustain electrode 12a and the sustain electrode 12b using the wall charges formed inside the lit cell in the sustain period to display an image.

However, since a high voltage pulse must be applied between the scan / hold electrode 12a and the sustain electrode 12b for preliminary discharge in the reset period, power consumption increases due to the high voltage. In addition, a strong discharge occurs in the entire cell due to the high voltage pulse applied between the scan / sustain electrode 12a and the sustain electrode 12b during this reset period. The brightness, i.e. the minimum brightness value, is raised. As a result, the contrast defined by the ratio of the minimum luminance to the maximum luminance is lowered, resulting in a problem that a high gradation image cannot be displayed. In order to prevent uneven brightness of a cell or a screen caused by wall charges excessively formed due to a strong discharge due to a high voltage pulse applied in the reset period, another pulse after supplying a high voltage pulse as shown in FIG. They have to supply very complex waveforms because they need to eliminate excessive wall charges.

Accordingly, it is an object of the present invention to provide a wall charge forming apparatus and method capable of forming even wall charges in a cell by causing a number of weak discharges by using an auxiliary electrode and an address electrode in a reset period.

Another object of the present invention is to provide a wall charge forming apparatus and method in which low power can be consumed by forming uniform wall charges by several weak discharges in a reset period.

It is still another object of the present invention to form a uniform wall charge by a plurality of weak discharges during a reset period, thereby preventing the minimum luminance value from rising due to a strong discharge, thereby increasing contrast and displaying a high gradation image. It is to provide a wall charge forming apparatus and method.

It is still another object of the present invention to provide an apparatus and method for forming wall charges which can increase the operation rate by preventing erroneous discharge of cells by forming uniform wall charges by weak discharges during a reset period.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a sectional view showing the structure of a PDP pixel cell of a conventional AC system.

FIG. 2 is a diagram showing waveforms applied to each electrode of FIG. 1 by an ADS method. FIG.

3 is a cross-sectional view showing the structure of an alternating current PDP pixel cell according to the present invention;

4 is a cross-sectional view illustrating a structure of a subcell among the pixel cells shown in FIG. 3.

FIG. 5 is a diagram showing waveforms applied to each electrode of FIG. 4 by the ADS method. FIG.

<Simple explanation of symbols for main parts of drawings>

10, 30: top glass 12a, 32a: scanning / holding electrode

12b, 32b: sustain electrode 14, 34: dielectric layer

16, 36: shield 18, 38: bulkhead

20, 40: lower glass 22, 42: address electrode

24, 44 phosphor 46: auxiliary electrode

48: second dielectric layer

In order to achieve the above object, the wall charge forming apparatus for a PDP according to the present invention, the upper plate glass which is the screen display unit, the lower plate glass facing the upper plate glass, partition wall formed at a predetermined height between the upper plate and the lower plate glass, A plasma display comprising a sustain electrode formed on the upper glass, a dielectric layer formed on the upper glass on which the sustain electrode is disposed, a protective layer formed on the dielectric layer, and a phosphor coated over the lower glass and the partition wall. A panel comprising: an address electrode disposed between a lower plate glass and a phosphor, a scan / hold electrode arranged in parallel with the sustain electrode on the upper plate glass, a barrier layer formed on a protective layer so as to face a partition wall, and an address electrode during reset discharge; And an auxiliary electrode for sequential discharge with the scan / hold electrode and for uniformly forming wall charges in the cell. And a gong.

In the method of forming a wall charge for a PDP according to the present invention, a first step of generating a primary discharge by applying an arbitrary voltage between the address electrode and the auxiliary electrode, and applying a second voltage between the auxiliary electrode and the scan / hold electrode to perform a secondary discharge It is characterized in that it comprises two steps to form a uniform wall charge in the interior of the subcell.

Other objects and advantages of the present invention in addition to the above object will become 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. 3 to 5.

3 is a cross-sectional view illustrating a structure of a PDP pixel cell including a wall charge device according to an exemplary embodiment of the present invention, and FIG. 4 is a cross-sectional view illustrating a detailed structure of one subcell in the pixel cell of FIG. 3.

The PDP pixel cell shown in FIG. 3 is composed of three subcells corresponding to red (R), green (G), and blue (B), and each subcell displays an image as shown in FIG. It consists of the lower plate glass 40 which opposes the upper plate glass 30 which is a surface, and the partition 38 formed in the predetermined height between this upper plate glass 30 and the lower plate glass 40. As shown in FIG. An inert gas such as neon (Ne), helium (He), xenium (Xe), or the like is sealed in the discharge space provided by the partition wall 38. On the top glass 30, two sustain electrodes, that is, the scan / hold electrode 32a and the sustain electrode 32b, are arranged side by side, and on the top glass 30 on which the sustain electrodes 32a and 32b are disposed. The dielectric layer 34 is formed flat. A protective film 36 is formed on the dielectric layer 34 to prevent damage to the dielectric layer 34 from sputtering of plasma particles due to discharge between the two electrodes 32a and 32b. An auxiliary electrode 46 is formed on both surfaces of the protective layer 36 facing the partition 38, and the second dielectric layer 48 is flat on the protective layer 36 on which the auxiliary electrode 46 is formed. Is formed. Here, the auxiliary electrode 46 serves to generate uniform wall charges inside the cell by causing the discharge of the address electrode 42 and the weak discharge several times during the reset period. An address electrode 42 is disposed on the lower platen glass 40, and on the lower platen glass 40 on which the address electrode 42 is disposed, red, green, and blue colors for emitting red, green, and blue visible light during discharge of the cell, respectively. Any one of the phosphors 44r, 44g, 44b is applied including a portion of the partition wall 38.

Referring to the detailed waveform diagram of each electrode shown in FIG. 5, a process of forming wall charges in a reset period in a pixel cell of a PDP according to the present invention will be described below.

First, a normal discharge is applied by applying a normal voltage between the address electrode 42 and the auxiliary electrode 46 to form a predetermined amount of wall charges inside the cell. In detail, a positive voltage pulse is applied to the address electrode 42 and a negative voltage pulse is applied to the auxiliary electrode 38 to cause discharge. As a result, ionized ions are collected at the auxiliary electrode 38 and electrons are collected at the address electrode 42, thereby forming a constant wall charge in the cell. At this time, the supply of the voltage to other electrodes, that is, the scan / sustain electrode 32a and the sustain electrode 32b, is stopped so as not to be affected.

Next, a normal voltage is applied between the auxiliary electrode 46 and the scan / hold electrode 32a to generate a second minute discharge, thereby neutralizing the wall charge formed in the first step. In detail, a positive voltage pulse is applied to the auxiliary electrode 48 and a negative voltage pulse is applied to the scan / hold electrode 32a to generate a discharge, thereby causing the discharge around the scan / hold electrode 32a. Positive ions collect in the dielectric layer 34 of the electrons and electrons collect around the auxiliary electrode 48. Accordingly, ions and electrons are present in the dielectric layer 34, and wall charges in the cell internal space formed in the first step are neutralized.

Subsequently, a wall charge is formed to apply sustain voltage to the cells to be lit by applying a voltage between the scan / sustain electrode 32a and the address electrode 42 to generate a scan discharge. In this case, the cells in a neutralized state are easily reacted by the wall charges uniformly formed in the reset period, so that the driving is possible even at a low voltage, and the operation rate is also improved by preventing mis-discharge. Then, the sustain pulse is alternately supplied to the scan / sustain electrode 32a and the sustain electrode 32b to cause sustain discharge, thereby displaying an image. At this time, the sustain discharge is generated at a low driving voltage by using the wall charges generated in the scan discharge period.

As described above, in the present invention, the primary discharge is caused between the auxiliary electrode and the address electrode during the reset period, and the secondary discharge is generated between the auxiliary electrode and the scan / hold electrode to form an even wall charge in the cell. Accordingly, the driving voltage can be lowered during the scanning discharge, thereby enabling low voltage driving, and preventing the erroneous discharge caused by the unbalanced wall charge as in the prior art, thereby improving the operation rate of the cell. In addition, in the present invention, by forming a uniform wall charge by using a weak discharge in the reset period, it is possible to prevent the increase in the brightness of the black level due to the conventional strong discharge to increase the contrast.

As described above, according to the apparatus and method for forming a PDP wall charge according to the present invention, a plurality of weak discharges are generated between the address electrode and the auxiliary electrode, and the auxiliary electrode and the scan / hold electrode in the reset section so as to be uniform inside the cell. It can form wall charges. Accordingly, according to the present invention, it is possible not only to lower the driving voltage for the scanning discharge but also to prevent the erroneous discharge caused by the unbalanced wall charge, thereby improving the operation rate of the cell. In addition, according to the present invention, by using the weak discharge to which the normal voltage is applied in forming the wall charge, by preventing the increase of the black level brightness due to the strong discharge, the contrast can be improved and the high gradation image can be realized. Become.

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 (5)

An upper plate glass that is a screen display unit, a lower plate glass facing the upper plate glass, a partition wall formed at a predetermined height between the upper plate glass and the lower plate glass, a sustain electrode formed on the upper plate glass, and the sustain electrode A plasma display panel comprising a dielectric layer formed on an upper plate glass, a protective layer formed on the dielectric layer, and a subcell unit including phosphors applied over the lower plate glass and the partition wall. An address electrode disposed between the lower pane and the phosphor; A scan / hold electrode disposed on the upper plate glass in parallel with the sustain electrode; And an auxiliary electrode formed on the protective layer so as to face the barrier rib and having a uniform discharge with the address electrode and the scan / hold electrode during reset discharge to uniformly form wall charges in the cell. Wall charge forming apparatus of the plasma display panel. The method of claim 1, And a second dielectric layer formed flat on the passivation layer on which the auxiliary electrode is formed. A top glass as a screen display unit, a bottom glass positioned to face the top glass, a partition wall formed at a predetermined height between the top glass and the bottom glass, a scan / hold electrode and a sustain electrode formed side by side on the top glass; And a dielectric layer formed on the upper glass on which the two electrodes are disposed, a protective layer formed on the dielectric layer, an auxiliary electrode formed on the protective layer to face the partition wall, and a second formed on the protective layer on which the auxiliary electrode is formed. A plasma display panel comprising a sublayer unit having a dielectric layer, an address electrode disposed on the lower plated glass, a lower plated glass on which the address electrode is disposed, and a phosphor coated over a partition wall. A first step of causing a primary discharge by applying an arbitrary voltage between the address electrode and the auxiliary electrode; And forming a uniform wall charge in the inside of the subcell by applying an arbitrary voltage between the auxiliary electrode and the scan / hold electrode to form a second discharge. . The method of claim 3, wherein In step 1 above And forming a constant wall charge by applying a positive voltage pulse to the address electrode and applying a negative voltage pulse to the auxiliary electrode to generate a weak discharge. The method of claim 3, wherein In step 2 above And forming a uniform wall charge by applying a positive voltage pulse to the auxiliary electrode and applying a negative pulse voltage to the scan / maintenance electrode to generate a weak discharge.