KR100299774B1 - High Speed Driving Method of Large Screen High Definition Plasma Display Panel - Google Patents

Abstract

The present invention relates to a high-speed driving method of a large-screen high-definition plasma display panel, comprising a selective writing step and a display discharge step in a plasma display panel driving method comprising a front writing step, a front erasing step, a selective writing step, and a display discharge step. Unlike the conventional method of expressing the gray scale by controlling the number of display discharges, the gray scale is controlled by controlling the intensity of the display discharge by controlling the amount of wall charge induced according to the brightness to be displayed by the pixel in the selective writing step. Even when the pixel expresses weak brightness, the weak discharge continuously occurs for a long time to improve the image quality, and by applying an erasing discharge pulse between the display discharges and the selective writing once per frame and reducing the wall charge to the initial value Selective compared to the conventional subfield method It is possible to drastically reduce the time spent in the mouth to drive at high speed.

Description

High Speed Driving Method of Large Screen High Definition Plasma Display Panel

The present invention relates to a high-speed driving method of a large-screen high-definition plasma display panel, wherein the pixel in the selective writing step and the display discharge step of the plasma display panel driving method comprising a front writing step, a front erasing step, a selective writing step, and a display discharge step. By controlling the intensity of the display discharge by controlling the amount of wall charges induced according to the brightness to be displayed, the gray level can be improved by improving the image quality by gradually expressing the weakness of the pixels. It is possible to drastically reduce the time required for selective writing by applying an erasing discharge pulse between the display discharge and the selective discharge only once for one frame and reducing the wall charge to an initial value. High speed driving method will be.

Plasma display panel has a structure in which a plurality of electrodes are arranged on two upper and lower substrates orthogonal to each other, and one or more inert gases are injected and sealed at a pressure of several hundred torr between them to create a discharge space. There are DC type and AC type.

The DC plasma display panel is manufactured so that the electrode is exposed to an inert gas, and the AC plasma display is formed by forming an insulating film on the electrode.

The pixels of the plasma display panel are formed at points where electrodes formed on upper and lower substrates cross vertically.

In the case of the DC plasma display panel, since the electrode is exposed to the discharge space, sputtering due to the ion of inert gas generated when the discharge occurs is inevitable, which is an important factor for shortening the life of the electrode. In order to control the increase in current caused by the decrease in the impedance of the space, a direct current resistance in mega-ohms must be connected in series with the electrode.

On the other hand, in the case of the AC plasma display panel, the electrode is not directly exposed to the discharge, thereby extending its lifespan, and improving the insulating film formed on the electrode to increase the secondary electron emission by the ion of the inert gas. The efficiency can be improved, and since DC current does not flow due to discharge, no additional resistance is required, which is advantageous over DC type plasma display panels.

The AC plasma display panel has a variety of types, such as a two-electrode type, a three-electrode type, and a form having more electrodes.

The two-electrode type has the structure described above, and the three-electrode type is the multifunction electrode 110 and the sustain discharge electrode 120 which are two kinds of electrodes parallel to each other on the upper substrate 101 of the upper and lower substrates as shown in FIG. 1. ) And a plurality of write whether electrodes 130 are disposed on the lower substrate 102. The insulating thin film 140 is formed on all electrodes by using a printing method and the like to facilitate secondary electron emission as necessary. The MgO thin film 150 is added and configured.

At this time, the write whether electrode 130 is separated into an insulator partition wall 160 to reduce interference between adjacent discharge spaces.

In addition, it is configured by adding a phosphor layer 170 that serves to convert the ultraviolet light generated by the discharge into visible light.

In the driving method of a three-electrode alternating current plasma display panel, a glow discharge is generated by applying a waveform as shown in FIG. 2 to each electrode.

That is, pulses 211 are applied to all dielectric discharge electrodes 120 of the plasma display panel and pulses 221 are applied to all multifunction electrodes.

The potential difference between the two types of electrodes becomes V _W + V _S by the applied voltage, and this value is larger than the breakdown voltage (BV) of the sealed discharge gas so that gas discharge occurs. It is called.

When the gas discharge is generated by the front write, a large number of electrons, ions of the inert gas, active species, etc. are generated within 1 ms and are moved to the electrode by electrical attraction.

If pulses 211 and 221 are applied for a sufficiently long time, the electrically polarized charged particles accumulate on the surface of the insulating layer on the electrode having the opposite polarity and form so-called wall charges.

When such wall charges accumulate, an electric field due to an externally applied voltage is generated between the electrode and the wall charges, and the electric field in the discharge space gradually becomes weaker and becomes discharged when the electric field falls below the critical electric field.

When the wall charges are removed, they gradually disappear through various reactions in the process of diffusion, but they remain in the order of several tens of microseconds or more, making the next discharge easier. In particular, the discharge cells have a memory capacity.

Immediately after the address discharge, a pulse 225 is applied to the sustain discharge electrode 120 to be added to the wall voltage generated by the previous address discharge to cause additional discharge.

The front erase step is to apply pulse 222 to the multifunction electrode 110. Since the wall voltage is formed by the two discharges just before, the pulse 222 generates a discharge even if the voltage of the pulse 222 is smaller than the breakdown voltage of the discharge gas.

Note that the width of pulse 222 for erasing discharge is smaller than at the stage of full writing.

When such a waveform is applied, discharge occurs in the discharge space, but since the width of the pulse is small and the time for the charged particles to move toward the electrode is short, wall charges do not accumulate in the insulating layer on the electrode.

The front writing and the front erasing described above are performed to uniformly control the internal state of many discharge cells in the plasma display panel.

That is, through this process, the wall charges of the discharge cells can be erased, and the state of all the discharge cells can be made to the state defined by the designer, thereby enabling predictable driving.

For example, when two discharge cells need to be discharged at the same intensity, when the discharge is applied by applying the same voltage to the two discharge cells without front writing and total erasing, the discharge cells having a lot of wall charges are more effective. Discharge does not occur in cells that generate strong discharges or have low wall charges, so that accurate representation of the image information is impossible.

After initialization of front write and front erase, write the image information to express.

That is, the multifunction electrode 110 is sequentially selected and applies the pulse 223. On the other hand, pulses 213 are applied to the write-in electrode 130 when discharge is necessary, and no voltage is applied.

At this time, the potential difference generated by the pulses 213 and 223 causes a sufficiently strong discharge, but the magnitude of the pulse 223 is smaller than the breakdown voltage BV so that no discharge occurs in the pixel to which only the pulse 223 is applied.

In this manner, the process of sequentially driving all the multifunction electrodes 110 to write desired image information is called a selective writing step.

When the selective writing is completed, sustain discharge pulses 224 and 231 are applied between all multifunction electrodes 110 and sustain discharge electrodes 120.

The voltage of this pulse is smaller than the breakdown voltage (BV) of the discharge gas, so that the discharge cannot be generated independently unless it is added to the wall voltage caused by the wall charge generated inside the discharge cell.

Therefore, only the discharge cells in which the write discharge has occurred in the selective writing step are caused by the discharge pulses, which is called display discharge, and this step is called display discharge step.

The sustain discharge pulses 224 and 231 in the plasma display panel operate at a frequency of several tens of KHz, and a subfield method as shown in FIG. 3 is used to express gray scales.

In FIG. 3, five subfields represent gray scales of one frame, and reference numeral 310 denotes an optional writing period, and 320, 330, 340, 350, and 360 denote a space between the multifunction electrode 110 and the sustain discharge electrode 120. FIG. The five subfields which display discharge by applying a voltage to it are shown.

One display discharge is implemented in the first subfield 320, two display discharges in the second subfield 330, four display discharges in the third subfield 340, eight in the fourth subfield 350, and In the fifth subfield 360, sixteen display discharges occur. Gradation display is realized by controlling the number of display discharges by combining these five subfields.

Since each subfield undergoes an optional writing step before display discharge starts, only less than 30% of one frame time is used for display discharge.

As described above, the conventional plasma display panel driving method applies one voltage to the multifunction electrode 110 and the write electrode 120 of the discharge cell to be written in the selective writing step, and the gray scale is realized by controlling the number of display discharges. It was.

Therefore, in this case, a very weak brightness pixel discharges only a portion of one frame, and the rest of the pixels are completely turned off, resulting in a bad image quality.

In other words, in the case of VGA-class plasma display panel, the widths of pulses 213 and 223 are set to about 3,. In this case, in order to have 256 gradations, 70% of the total discharge time is used for sequential writing and for display discharges that express actual information. Since only 30% of the rest can be used, it is a problem to improve brightness, which will be more serious in the HDTV plasma display panel currently being developed.

The present invention has been made to solve the above problems, and in the method of driving a plasma display panel comprising a front writing step, a front erasing step, a selective writing step, and a display discharge step, the selective writing step and the display discharge step are performed. Unlike the conventional method of expressing gradation by controlling the number of display discharges, it is possible to control the intensity of the display discharge by controlling the amount of wall charges induced according to the brightness to be displayed by the pixel in the selective writing step. Even when the pixel expresses weak brightness, the weak discharge continuously occurs for a long time to improve the image quality, and by applying an erasing discharge pulse between the display discharges and the selective writing once per frame and reducing the wall charge to the initial value Compared to the conventional subfield method, it consumes selective writing. It is an object of the present invention to provide a high-speed driving method of a large-screen high-definition plasma display panel capable of driving at high speed since the time can be drastically reduced.

1 is a structure of a three-electrode AC plasma display panel

2 is a voltage waveform diagram applied to each electrode of a conventional plasma display panel;

3 is an example of expressing the gradation of one frame with five subfields in the conventional method.

4 is a waveform diagram of a method of fixing a width of a selective write pulse applied to a write-in electrode and changing a voltage value in the present invention;

FIG. 5 is a waveform diagram of a method of changing a width and maintaining a voltage of a selective write pulse applied to a write-in electrode according to the present invention.

6 is a waveform diagram of a voltage applied to each electrode in the selective writing step of the present invention;

<Description of the symbols for the main parts of the drawings>

101: upper substrate 102: lower substrate

110: multifunction electrode 120: sustain discharge electrode

130: writing or not electrode 140: insulating thin film

150: MgO thin film 160: insulator partition wall

170: phosphor layer

Hereinafter, with reference to the accompanying drawings will be described in more detail the method configuration and operation of the present invention.

In the selective writing step of the present invention, two methods are specifically used to control the amount of wall charges induced according to the brightness to be displayed by the pixel.

First, as shown in FIG. 4, the width of the selective write pulse 410 applied to the write-in electrode 130 is fixed and the voltage value is changed. That is, the wall charges induced by changing the intensity of the selective write discharge are controlled.

Second, as shown in FIG. 5, the voltage of the selective writing pulse 410 applied to the writing-or-defining electrode 130 is maintained at a constant value and the width thereof is changed. In other words, the wall charge becomes larger when the discharge occurs due to the potential difference of the same magnitude, so that the amount of the wall charge can be controlled by changing the width of the selective write pulse.

While scanning the multifunction electrode 110 in these two methods, a different amount of wall charge is induced according to the brightness to be displayed on the discharge cells in each row, and the selective writing step ends when the setting up to the last multifunction electrode is completed.

For convenience, this selective writing method is called "weighted selective write".

When the selective writing step is completed, the display discharge step is entered, and pulses 224 and 223 as shown in FIG. 6 are applied between the multifunction electrode 110 and the sustain discharge electrode 120.

Since the voltages applied to all the discharge cells are the same but the amount of wall charges induced therein is different, the intensity of discharge generated by these pulses is different, and the gray level is displayed according to the intensity of this discharge.

In the case of a discharge cell with a small amount of wall charge, even though the same pulse as the display discharge pulse applied to the discharge cell with a large amount of wall charge is applied, the intensity of the discharge is relatively low, but a weak discharge is continuously generated. Even the pixels to be expressed can express gray scales with good image quality.

On the other hand, even when the discharge cells in which the wall charges are formed to be very small in the selective writing step are repeatedly discharged, as the number of display discharges is repeated, more and more wall charges are induced. In order to prevent this, after the predetermined number of display discharges have occurred, an extremely small erase discharge pulse 610 is applied to all discharge cells to reduce wall charges, and then a display discharge pulse is applied to prevent discharge. Keep the difference in the amount of wall charge you have. In this case, the erase discharge pulse 610 may be applied several times during one frame.

Accordingly, the present invention significantly reduces the time required for selective writing compared to the conventional subfield method by applying an erasing discharge pulse between the display discharges and performing the selective writing only once for one frame and reducing the wall charge to an initial value. It can be driven at high speed.

Actually, since the selective writing voltage applied to the writing electrode 130 is about 60V, the voltage difference between grayscales is only about 0.23V to realize 256 grayscales, and the difference is due to the difference in discharge characteristics between discharge cells. Since the difference may be almost eliminated, and gray scale implementation becomes uncertain, in order to solve this problem, it is necessary to drive a modified version of the conventional subfield method.

The first method is to increase the voltage difference between grayscales by reducing the voltage application step of the selective write pulse applied to the write-in electrode, thereby increasing the difference in the wall charge amount, and driving one frame by dividing it into predetermined subfields. The second method is to reduce the width applying step of the selective write pulse applied to the write-in electrode to increase the difference in the amount of wall charges by increasing the pulse width between gray levels, and to drive one frame by dividing it into predetermined subfields. In this way, high gradation can be realized and discharge efficiency can be improved.

For example, if the voltage applied to the writing electrode is divided into seven stages of 0, 10, 20, 30, 40, 50, and 60V, and one frame is divided into three subfields, the number of gray scales that can be realized is 7 × 7. X7 = 343.

In this case, the voltage difference between the gray scales is 10V, which is 40 times higher than when the subfield method is not used, thereby enabling more stable operation.

Therefore, the present invention can realize 343 gray scales using only three subfields, compared with the conventional subfield method using 8 subfields per frame for 256 gray scales, thus 2.7 times the time used for display discharge. Increasing the driving speed of the plasma display panel can be dramatically improved.

The effect obtained by using the present invention described above should be displayed by the pixel in the selective write step and the display discharge step of the plasma display panel driving method including the front write step, the front erase step, the selective writing step, and the display discharge step. By controlling the intensity of the display discharge by controlling the amount of wall charges induced according to the brightness to be displayed, gradation is expressed so that even a pixel with very low brightness can be continuously discharged for a long time to improve image quality. By applying an erase discharge pulse that only performs selective writing once and reduces the wall charge to an initial value between the display discharges, the time required for selective writing can be drastically reduced, so that a high speed drive can be achieved.

Claims (5)

Applying a waveform to each electrode to generate a glow discharge to form wall charges, a front write step of applying a waveform to the multifunction electrode to erase the wall charges of the discharge cell, and sequentially applying pulses to write desired image information In the method of driving a plasma display panel comprising a selective discharge step, and a display discharge step of applying a sustain discharge pulse to discharge only discharge cells generated in the selective write step. A driving method that controls the amount of wall charges in steps of as many gray scales as desired.In order to express a specific gray scale in one pixel, a wall charge corresponding to the specific gray scale is induced during the selective writing step, and then all pixels In the display discharge step in which the same waveform is applied to the display waveform, the brightness corresponding to the desired gray scale is expressed. During the display discharge step, a signal consisting of a predetermined number of display discharge pulses and one erase pulse is repeatedly applied, and one selective writing step is performed. And a single fray in one display discharge step. The high-speed driving method of the large-screen high-definition plasma display panel according to claim 1, wherein a method of controlling the amount of wall charge is used to change the voltage level of the selective write pulse applied to the write-in electrode. The high-speed driving method of the large-screen high-definition plasma display panel according to claim 1, wherein a method of controlling the amount of wall charges is used to change the width of the selective write pulse applied to the write-in electrode. 2. The discharge cell of claim 1, wherein the discharge cells with a small amount of wall charge are relatively weak but consistently weak even though the same pulse as the display discharge pulse applied to the discharge cell with a large amount of wall charge is applied. Therefore, the high-speed driving method of the large-screen high-definition plasma display panel, characterized in that it is possible to express good gradation even in pixels expressing weak brightness. 2. The large-screen high-definition plasma according to claim 1, wherein the selective writing is performed only once during one frame, and the time required for selective writing can be reduced by applying the erase discharge pulse several times between the display discharges during the display discharge period. High speed driving method of display panel.