KR100468414B1 - Method of driving plasma display panel - Google Patents

Abstract

The present invention relates to a method of driving a plasma display panel for removing wall charges remaining after an erase discharge.

The method of driving a plasma display panel according to the present invention includes a first row electrode, a second row electrode, and a column electrode, and discharge cells are disposed at intersections of the first row electrode, the second row electrode, and the column electrode. An initialization period for initializing a discharge cell, an address period for selecting the discharge cell, a sustain period for maintaining discharge of the selected discharge cell, and an erase period for erasing light emission of the discharge cell; Supplying a lamp pulse to the first row electrode during the erasing period to cause weak discharge between the first row electrode and the second row electrode; And applying a square wave pulse to the second row electrode so as to overlap the lamp pulse when the voltage level of the lamp pulse approaches the sustain voltage level applied during the sustain period, thereby erasing wall charges. .

Description

Driving method of plasma display panel {METHOD OF DRIVING 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 for removing wall charges remaining after an erase discharge.

Plasma Display Panel (hereinafter referred to as "PDP") is used to excite and emit phosphors by using ultraviolet rays generated when an inert mixed gas such as He + Xe, Ne + Xe, He + Xe + Ne is discharged. Will be displayed. Such PDPs are not only thin and large in size, but also have improved in image quality due to recent technology development.

Referring to FIG. 1, a discharge cell of a conventional three-electrode AC surface discharge type PDP has a scan electrode (Y) and a sustain electrode (Z), and an address electrode (X) orthogonal to the scan electrode (Y) and the sustain electrode (Z). It is provided.

At the intersection of the scan electrode Y, the sustain electrode Z and the address electrode X, a cell 1 for displaying any one of red, green and blue is formed. The scan electrode Y and the sustain electrode Z are formed on an upper substrate (not shown). On the upper substrate, a dielectric layer and an MgO protective layer (not shown) are stacked. The address electrode X is formed on the lower substrate (not shown). On the lower substrate, partition walls are formed to prevent optical and electrical interference between horizontally adjacent cells. Phosphors are excited on the lower substrate and the partition walls to be excited by vacuum ultraviolet rays and emit visible light. An inert mixed gas such as He + Xe, Ne + Xe, He + Xe + Ne is injected into the discharge space between the upper substrate and the lower substrate.

The PDP is time-divisionally driven by dividing one frame into several subfields having different number of emission times in order to implement grayscale of an image. Each subfield is divided into an initialization period for initializing the full screen, an address period for selecting a scan line and selecting a cell in the selected scan line, and a sustain period for implementing gray levels according to the number of discharges. For example, when the image is to be displayed with 256 gray levels, as shown in FIG. 2, the frame period (16.67 ms) corresponding to 1/60 second is divided into eight subfields SF1 to SF8. As described above, each of the eight subfields SF1 to SF8 is divided into an initialization period, an address period, and a sustain period. The initialization period and the address period of each subfield are the same for each subfield, while the sustain period and the number of sustain pulses allocated thereto are 2 ⁿ (n = 0,1,2,3,4,5,6) in each subfield. , 7).

3 shows a drive waveform of a PDP supplied to a conventional subfield.

Referring to FIG. 3, the PDP is divided into an initialization period for initializing the full screen, an address period for selecting a cell, a sustain period for maintaining the discharge of the selected cell, and an erasing period for removing the wall charges formed in the sustain period. Driven.

In the initialization period, the rising ramp waveform Ramp-up is simultaneously applied to all the scan electrodes Y in the setup period SU. This rising ramp waveform (Ramp-up) causes a discharge in the cells of the full screen. By this setup discharge, positive wall charges are accumulated on the address electrode X and the sustain electrode Z, and negative wall charges are accumulated on the scan electrode Y. After the rising ramp waveform Ramp-up is supplied in the set-down period SD, the falling ramp waveform Ramp-down falling at the positive voltage lower than the peak voltage of the rising ramp waveform Ramp-up is applied to the scan electrodes ( Is simultaneously applied to Y). Ramp-down causes a slight erase discharge in the cells, thereby partially erasing the excessively formed wall charge. This set-down discharge causes the wall charges to be uniformly retained in the cells so that the address discharge can be stably generated.

In the address period, the negative scan pulse scan is sequentially applied to the scan electrodes Y, and the positive data pulse data is applied to the address electrodes X in synchronization with the scan pulse scan. As the voltage difference between the scan pulse and the data pulse and the wall voltage generated during the initialization period are added, an address discharge is generated in the cell to which the data pulse is applied. In the cells selected by the address discharge, wall charges are formed such that a discharge can occur when a sustain voltage is applied.

The sustain electrode Z is supplied with a positive DC voltage Zdc during the set down period and the address period.

In the sustain period, sustain pulses sus are alternately applied to the scan electrodes Y and the sustain electrodes Z. FIG. The cell selected by the address discharge has a sustain discharge, that is, a display discharge between the scan electrode (Y) and the sustain electrode (Z) whenever the sustain voltage (sus) is applied as the wall voltage and the sustain pulse (sus) in the cell are added. This will happen. The sustain pulse sus has a pulse width of about 2 to 3 ㎲ so that the discharge can be stabilized. It is discharged within approximately 0.5 to 1 시점 after the time when the sustain pulse (sus) is generated, but the sustain pulse (sus) after the discharge occurs to form a wall charge to the extent that can cause the next discharge, This is because the sustain voltage (Vs) should be maintained at about 2 to 3 mA.

In the erase period, ramp waveforms are supplied to the sustain electrode Z to erase wall charge remaining in the cells of the full screen. When the ramp-ers are supplied to the sustain electrode Z, the potential difference between the sustain electrode Z and the scan electrode Y gradually increases as shown in FIG. 4, and the sustain electrode Z and the scan are gradually increased. The weak discharge occurs continuously between the electrodes Y. The weak discharge generated at this time erases wall charges existing in the cells in which the sustain discharge has occurred.

On the other hand, in addition to the ramp waveform (ramp-ers), as shown in Figure 5 in order to erase the wall charge existing in the cells in which the sustain discharge has occurred, the square wave pulse (rw-ers) may be supplied with the sustain electrode (Z). The pulse width of the square wave pulse (rw-ers) is set to about 1 kW, causing relatively strong discharge in a short time at the sustain voltage (Vs), thereby erasing wall charge in the cell. Since the discharge generated due to the square wave pulse (rw-ers) has a short time for maintaining the sustain voltage Vs, the discharge does not spread along the scan electrode Y and the sustain electrode Z.

Cells whose wall charges are erased due to ramp-ers or square-wave pulses (rw-ers) cannot generate discharges because the wall voltage in the cells is low even when the sustain pulses are applied again.

However, ramp-ers and square-wave pulses (rw-ers) for erasing wall charges generated during sustain discharge have many disadvantages. In detail, ramp-ers can cause weak discharges in succession to eliminate wall charges, but because the discharges are too weak, they do not completely erase wall charges to a satisfactory level and leave some wall charges. . Square wave pulses (rw-ers) are high voltage pulses with a peak voltage of several hundreds [V] and a small pulse width of 1㎲, which is a delay characteristic of PDP when considering PDP with a large capacitive load. Due to this, it is difficult to implement circuit. In addition, since the square wave pulse (rw-ers) causes a strong discharge, there is a problem that the discharge is diffused toward the adjacent cell.

Accordingly, an object of the present invention is to provide a method of driving a PDP for removing wall charges remaining after an erase discharge.

1 is a plan view schematically showing an electrode arrangement of a conventional three-electrode AC surface discharge type plasma display panel.

2 is a diagram illustrating a frame structure of a PDP for implementing 256 gray levels.

3 is a waveform diagram showing a drive waveform for driving a conventional PDP.

4 is a waveform diagram showing a rising period of a conventional lamp pulse for canceling sustain discharge.

Fig. 5 is a waveform diagram showing the pulse width of a conventional square wave pulse for canceling sustain discharge.

6 is a waveform diagram illustrating a method of driving a plasma display panel according to an exemplary embodiment of the present invention.

FIG. 7 is an enlarged waveform diagram illustrating a lamp pulse and a square wave pulse shown in FIG. 6.

FIG. 8 is a waveform diagram illustrating another form of the lamp pulse and the square wave pulse shown in FIG. 6.

In order to achieve the above object, a driving method of a PDP according to an embodiment of the present invention includes a first row electrode, a second row electrode and a column electrode, and an intersection point between the first row electrode and the second row electrode and the column electrode. A discharge cell is disposed in the battery cell, an initialization period for initializing the discharge cell, an address period for selecting the discharge cell, a sustain period for maintaining discharge of the selected discharge cell, and an erase for erasing light emission of the discharge cell Includes a period of time; Supplying a lamp pulse to the first row electrode during the erasing period to cause weak discharge between the first row electrode and the second row electrode; And applying a square wave pulse to the second row electrode so as to overlap the lamp pulse when the voltage level of the lamp pulse approaches the sustain voltage level applied during the sustain period, thereby erasing wall charges. .

The lamp pulse is characterized in that the voltage gradually increases to the voltage level of the sustain pulse.

The ramp pulse is characterized in that the voltage is instantaneously increased to the voltage level of the sustain pulse in synchronization with the square wave pulse.

Bipolar wall charges are formed in the first row electrode, and negative wall charges are formed in the second row electrode.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 6 to 8.

6 is a waveform diagram illustrating a method of driving a PDP according to the present invention.

Referring to FIG. 6, in the PDP according to the present invention, one frame period includes an initialization period for initializing a full screen, an address period for selecting a cell, a sustain period for maintaining a discharge of the selected cell, and a wall generated in the sustain period. Time division driving is performed by dividing the erase period for recombining the charge and the space charge.

In the initialization period, the rising ramp waveform Ramp-up is simultaneously applied to all the scan electrodes Y in the setup period SU. This rising ramp waveform (Ramp-up) causes a discharge in the cells of the full screen. By this setup discharge, positive wall charges are accumulated on the address electrode X and the sustain electrode Z, and negative wall charges are accumulated on the scan electrode Y. After the rising ramp waveform Ramp-up is supplied in the set-down period SD, the falling ramp waveform Ramp-down falling at the positive voltage lower than the peak voltage of the rising ramp waveform Ramp-up is applied to the scan electrodes ( Is simultaneously applied to Y). Ramp-down causes a slight erase discharge in the cells, thereby partially erasing the excessively formed wall charge. By this set-down discharge, the wall charges such that the address discharge can be stably generated remain uniformly in the cells.

In the address period, the negative scan pulse scan is sequentially applied to the scan electrodes Y, and the positive data pulse data is applied to the address electrodes X in synchronization with the scan pulse scan. As the voltage difference between the scan pulse and the data pulse and the wall voltage generated in the initialization period are added, an address discharge is generated in the cell to which the data pulse is applied. In the cells selected by the address discharge, wall charges are formed such that a discharge can occur when a sustain voltage is applied.

The sustain electrode Z is supplied with a positive DC voltage Zdc during the set down period and the address period.

In the sustain period, sustain pulses sus are alternately applied to the scan electrodes Y and the sustain electrodes Z. FIG. The cell selected by the address discharge has a sustain discharge, that is, a display discharge between the scan electrode Y and the sustain electrode Z whenever the sustain pulse sus is applied as the wall voltage and the sustain pulse sus are added. This will happen.

In the erase period, the lamp pulse RP is supplied to the sustain electrodes Z, and the square wave pulse SP is supplied to the scan electrodes Y to erase the wall charges and the space charges generated during the sustain period.

That is, the lamp pulse RP is applied to the sustain electrode Z to erase the wall charges due to the micro discharge occurring between the sustain electrodes Z and the scan electrodes Y. In addition, the rectangular wave pulse SP is applied to the scan electrode Y to overlap the lamp pulse RP applied to the sustain electrode Z for a predetermined time, thereby erasing the residual wall charges formed in the discharge cell. At this time, positive wall charges are formed on the sustain electrode Z, and negative wall charges are formed on the scan electrode Y.

In detail, when the lamp pulse RP is supplied to the sustain electrode Z, the potential difference between the sustain electrode Z and the scan electrode Y gradually increases, and the sustain electrode Z and the scan electrode Y are increased. Weak discharge occurs continuously. At this time, the wall charges existing in the cells in which the sustain discharge has occurred are caused by the weak discharge generated during the rising period in which the lamp pulse RP rises to the sustain voltage Vs. Thereafter, to remove the remaining wall charges that are not erased, immediately after the lamp pulse RP is applied to the sustain electrode Z as shown in FIG. 7 or to the sustain electrode Z as shown in FIG. 8. The square wave pulse SP is applied to the scan electrode Y while the lamp pulse RP is applied.

As shown in FIG. 8, when the square wave pulse SP is applied to the scan electrode Y while the lamp pulse RP is applied to the sustain electrode Z, the lamp pulse RP is applied to the sustain electrode Z. ) Increases momentarily to the final voltage Vs of the lamp pulse RP.

The square wave pulse SP applied to the scan electrode Y suppresses wall charge formation after erasing discharge, neutralizes bipolar wall charge formed on the sustain electrode Z, and retains wall charge remaining after the erase operation. Minimize the amount of.

The sustain electrode (Z) and the scan electrode (Y) may change the shape of the pulse applied according to the position and polarity of the wall charge to be erased.

As described above, the driving method of the PDP according to the present invention applies a square wave pulse to the scan electrode immediately after or while the lamp pulse is applied to the sustain electrode. This square wave pulse suppresses the wall charge formation after the erase discharge and reduces the amount of wall charge remaining after the erase discharge. The driving method of this PDP can be applied to 50-inch WXGA class.

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 (4)

An initializing period having a first row electrode, a second row electrode, and a column electrode, wherein a discharge cell is disposed at an intersection point of the first row electrode, the second row electrode, and the column electrode; A driving method of a plasma display panel comprising an address period for selecting the discharge cells, a sustain period for maintaining the discharge of the selected discharge cells, and an erasing period for erasing light emission of the discharge cells. Supplying a lamp pulse to the first row electrode during the erasing period to cause weak discharge between the first row electrode and the second row electrode; And applying a square wave pulse to the second row electrode so as to overlap with the lamp pulse when the voltage level of the lamp pulse approaches the sustain voltage level applied during the sustain period, thereby erasing wall charges. A method of driving a plasma display panel. The method of claim 1, And the lamp pulse gradually increases in voltage to the voltage level of the sustain pulse. The method of claim 1, And the lamp pulse increases in voltage instantaneously to the voltage level of the sustain pulse in synchronization with the square wave pulse. The method of claim 1, A positive electrode wall charge is formed in the first row electrode, and a negative electrode wall charge is formed in the second row electrode.