KR20030006436A - Driving Method of Plasma Display Panel - Google Patents

Abstract

PURPOSE: A method for driving a plasma display panel(PDP) is provided to prevent a mis-discharge at an off-cell by partially floating the potential of the data electrode during the sustain period and by keeping the level of sustain pulse as a ground level if the condition is equal to the address discharge condition. CONSTITUTION: A method for driving a plasma display panel(PDP) includes the steps of: implementing a sustain discharge by alternatively applying a sustain discharge pulse(SUSP) to a scan electrode(32Y) and a sustain electrode(32Z); floating a data electrode(30X) during the sustain discharge period; and maintaining the data electrode(30X) to be a ground level(GND) when the level of the sustain discharge pulse(SUSP) applied to the scan electrode(32Y) and the sustain electrode(32Z) is equal to the level during the addressing discharge.

Description

Driving method of plasma display panel {Driving Method of 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 method of driving a plasma display panel that selectively floats data electrodes to remove erroneous discharge conditions while improving driving efficiency and panel life.

Plasma Display Panel (hereinafter referred to as "PDP") is a display device using visible light generated from a phosphor when vacuum ultraviolet rays generated by gas discharge excite the phosphor. PDP is thinner and lighter than Cathode Ray Tube (CRT), which has been the mainstay of display means, and has the advantage of being able to realize high definition large screen. PDP is composed of a plurality of discharge cells arranged in a matrix form, one discharge cell constitutes a pixel of the screen.

1 is a perspective view showing a discharge cell structure of a conventional three-electrode AC surface discharge type PDP.

Referring to FIG. 1, a discharge cell of a conventional three-electrode AC surface discharge type PDP includes scan electrodes 12Y and sustain electrodes 12Z formed on an upper substrate 10, and data formed on a lower substrate 18. An electrode 20X is provided.

The upper dielectric layer 14 and the passivation layer 16 are stacked on the upper substrate 10 having the scan electrode 12Y and the sustain electrode 12Z side by side. In the upper dielectric layer 14, wall charges generated during plasma discharge are accumulated. The protective layer 16 prevents damage to the upper dielectric layer 14 due to sputtering generated during plasma discharge and increases discharge efficiency of secondary electrons. As the protective film 16, magnesium oxide (MgO) is usually used. The lower dielectric layer 22 and the partition wall 24 are formed on the lower substrate 18 on which the data electrode 20X is formed, and the phosphor layer 26 is coated on the lower dielectric layer 22 and the partition wall 24. The data electrode 20X is formed in the direction crossing the scan electrode 12Y and the sustain electrode 12Z. The partition wall 24 is formed in parallel with the data electrode 20X to prevent ultraviolet rays and visible light generated by the discharge from leaking to the adjacent discharge cells. The phosphor layer 26 is excited by ultraviolet rays generated during plasma discharge to generate visible light of any one of red, green, and blue. Inert gas for gas discharge is injected into the discharge space provided between the upper substrate 10 / lower substrate 18 and the partition wall 24.

The PDP cell of this structure is selected by the counter discharge between the data electrode 20X and the scan electrode 12Y, and then sustains the discharge by the surface discharge between the scan electrode 12Y and the sustain electrode 12Z. In the PDP cell, the fluorescent material 26 emits light by ultraviolet rays generated during the sustain discharge, so that visible light is emitted outside the cell to display an image. In this case, the PDP adjusts the discharge sustain period of the cell, that is, the number of sustain discharges, according to the video data, thereby implementing gray scale for displaying an image.

The PDP is driven by an ADS (Address and Display Period Separated) method in which one frame is driven by dividing a frame into several subfields having different discharge times in order to express gray levels of an image.

Each subfield is further divided into a reset period for generating discharge uniformly, an address period for selecting a discharge cell, and a sustain period for expressing gray scale according to the number of discharges. For example, when the image is to be displayed with 256 gray levels, the frame period (16.67 ms) corresponding to 1/60 second is divided into eight subfields. Each of the eight subfields is further divided into an address period and a sustain period. Here, the reset period and the address period of each subfield are the same for each subfield, while the sustain period is 2 ⁿ (n = 0,1,2,3,4,5,6,7) in each subfield. Is increased. In this way, since the sustain period is different in each subfield, the gray level of the image can be expressed.

Referring to FIG. 2, the reset period is divided into a set-up period and a set-down period. In the setup period, the rising ramp waveform ramp1 is supplied to the scan electrode 12Y, and in the set-down period, the ramp ramp ramp2 is supplied.

In the setup period, a weak reset discharge occurs due to the rising ramp waveform ramp1, and wall charges are accumulated in the cell.

In the set-down period, the wall ramp in the cell is appropriately erased by the falling ramp waveform ramp2 so that the wall charge is reduced to assist the next address discharge without causing an erroneous discharge. In addition, in order to reduce the wall charge, a positive DC voltage Vs is supplied to the sustain electrode 12Z in the set down period. When the scanning electrode 12Y supplied with the falling ramp waveform ramp2 becomes relative to the sustain electrode 12Z supplied with the positive DC voltage Vs, the negative polarity becomes negative, that is, the polarity is reversed. The wall charges generated during the setup period are reduced.

In the address period, the address discharge is caused by the scan voltage Vscan applied to the scan electrode 12Y and the data voltage data applied to the data electrode 20X. The wall charge formed by this address discharge is maintained for other discharge cells during the address period.

In the sustain period, the sustaining discharge is started in the discharge cells in which the triggering pulse TP is supplied to the scan electrode 12Y at the beginning to sufficiently wall charge in the address period. Subsequently, the sustain pulse SUSP is alternately supplied to the scan electrode 12Y and the sustain electrode 12Z to maintain the sustain discharge during the sustain period so that the desired gray scale is displayed.

In the erase period, the erase pulse EP is supplied to the sustain electrode 12Z to stop the discharge that was held.

As described above, in the conventional PDP driving method, the data electrode 20X maintains the ground potential state during the sustain period. Since a high voltage pulse of about 200 V is alternately applied between the scan electrode 12Y and the sustain electrode 12Z, a predetermined amount is formed on the data electrode 20X formed at intervals of about 100 μm in height of the partition wall 24. Wall charges accumulate. At this time, half the wall voltage of the sustain voltage is accumulated on the data electrode 20X in the cell. This is because the scan electrodes 12Y and the sustain electrodes 12Z are alternately applied with the voltages of the sustain voltage and the ground potential. As a result, the reason why the wall voltage is formed on the data electrode 20X during the sustain period is because a ground potential is applied to the data electrode 20X itself.

Thus, when wall charges are formed on the data electrode 20X, sustain discharge does not occur sufficiently, resulting in a problem of low discharge efficiency.

In order to solve this problem, a driving method for increasing the driving efficiency of the PDP by floating the data electrode 20X during the sustaining period has been proposed as shown in FIG. 3. The wall charge is accumulated by maintaining the ground potential at the data electrode 20X. If the data electrode 20X is floated to prevent the wall voltage from being accumulated, the sustain discharge is generated more efficiently.

However, since the data electrode 20X is in the floating state during the sustain period, in-phase organic pulses SUXX induced by the alternating sustain pulses SSUS are generated at the data electrodes 20X, thereby causing an erroneous discharge. In detail, during the sustain period, when the discharge condition B between the scan electrode 12Y and the sustain electrode 12Z becomes the same as the discharge condition A at the address, the cell is turned on in the off discharge cell. ) Discharge occurs. That is, the positive electrode pulse SUSX is applied to the data electrode 20X while the scan electrode 12Y addressed in the sustain period is in the ground state GND, and the sustain electrode 12Z is in the sustain voltage level of the sustain discharge pulse SSUSP. ) To abandon the false discharge.

Accordingly, it is an object of the present invention to provide a method of driving a plasma display panel that selectively floats data electrodes to remove erroneous discharge conditions while improving driving efficiency and panel life.

1 is a perspective view showing a discharge cell structure of a conventional three-electrode AC surface discharge type PDP.

FIG. 2 is a drive waveform diagram for driving a discharge cell of the PDP shown in FIG.

3 is a waveform diagram showing a condition of occurrence of false discharge in a sustain period;

4 is a driving waveform diagram for driving a discharge cell of a PDP according to the present invention;

<Explanation of symbols for main parts of drawing>

10: upper substrate 12Y, 32Y: scanning electrode

12Z, 32Z: sustain electrode 14: dielectric layer

16: protective film 18: lower substrate

20X, 30X: Data electrode 24: Bulkhead

26: phosphor layer

In order to achieve the above object, the driving method of the plasma display panel of the present invention is to maintain the ground level when the level of the sustain pulse applied to the scan electrode and the sustain electrode is the same as that at the addressing discharge. It features.

Other objects and features of the present invention in addition to the above objects will become apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, a preferred embodiment of the present invention will be described with reference to FIG. 4.

Referring to FIG. 4, the driving waveform according to the driving method of the plasma display panel of the present invention is largely divided into four periods: a reset period for uniformizing the initial condition of the panel to a desired state, an address period for selecting discharge cells, It is divided into a sustain period for expressing gradation and an erasing period for erasing discharge according to the number of discharges.

The reset period is divided into a set-up period and a set-down period. In the set-up period, the rising ramp waveform ramp1 is supplied to the scan electrode 32Y, and in the set-down period, the falling ramp waveform ramp2 is supplied.

In the setup period, a weak reset discharge occurs due to the rising ramp waveform ramp1, and wall charges are accumulated in the cell.

In the set-down period, the wall ramp in the cell is appropriately erased by the falling ramp waveform ramp2 so that the wall charge is reduced to assist the next address discharge without causing an erroneous discharge. In addition, in order to reduce wall charge, a positive DC voltage Vs is supplied to the sustain electrode 32Z during the setdown period. The negative polarity (-) becomes greater than that of the scan electrode 32Y to which the falling ramp waveform ramp2 is supplied to the sustain electrode 32Z to which the positive DC voltage Vs is supplied. This reduces the wall charges generated during setup.

In the address period, the address discharge is caused by the scan voltage Vscan applied to the scan electrode 32Y and the data voltage data applied to the data electrode 30X. The wall charge formed by this address discharge is maintained for other discharge cells during the address period.

In the sustain period, the sustaining discharge is started in the discharge cells in which the triggering pulse TP is supplied to the scan electrode 32Y at the beginning to sufficiently wall charge in the address period. Subsequently, the sustain pulse SupP is alternately supplied to the scan electrode 32Y and the sustain electrode 32Z to maintain the sustain discharge during the sustain period so that the desired gray scale is displayed.

In the erase period, the erase pulse EP is supplied to the sustain electrode 32Z to stop the discharge that was held.

In this sustain period, the data electrode 30X maintains the ground level GND when the addressing scan electrode 32Y is at the ground level GND during the sustain discharge period. In addition, the data electrode 30X is in a floating state when the sustaining discharge pulse SSUS is supplied to the scanning electrode 32Y addressing during the sustaining discharge period. In other words, the data electrode 30X maintains the ground level under the condition that the level of the sustain pulse applied to the scan electrode 32Y and the sustain electrode 32Z is the same as the level at the addressing discharge, and floats during other periods. It becomes a state.

As described above, when the addressing discharge condition is the same in the sustain period, the error discharge condition is eliminated by grounding the data electrode 30X. In detail, in the sustain period, the data electrode 30X is in a selective floating state by an on / off operation of a switching element (not shown). That is, when the sustain pulse SSUS is supplied to the scan electrode 32Y, the switching device is turned off to maintain the floating state. When the scan electrode 32Y is at the ground level GND, the switching device is turned on to ground voltage GND. To supply. Accordingly, in the sustain period, the data electrode 30X is in a floating state for half of the number of sustain discharge pulses, that is, partially so as to have an in phase with the sustain pulse SSUS of the scan electrode 32Y.

As described above, the driving method of the plasma display panel according to the present invention prevents the miscellaneous discharge in the off-cell by partially floating the potential of the data electrode during the sustain period, and maintaining it at the ground level when the address discharge condition is the same. do.

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 (2)

A driving method of a plasma display panel in which sustain discharge is applied by alternately applying a sustain pulse to a scan electrode and a sustain electrode, and a data electrode is floated during the sustain discharge period. And the data electrode maintains a ground level when the level of the sustain pulses applied to the scan electrode and sustain electrode is the same as that at the addressing discharge. The method of claim 1, And the data electrode maintains a floating state when the sustain pulse is supplied to the scan electrode.