KR20080004947A - Plasma display device and driving method thereof - Google Patents

Abstract

A plasma display apparatus and a driving method thereof are provided to prevent erase discharge by generating main discharge when a final sustain discharge pulse is applied. A plasma display apparatus includes a plasma display panel(100), a controller(200), and drivers(300,400,500). The plasma display panel includes first and second electrodes, and third electrodes to cross with the first and second electrodes. The controller dives a frame into sub-fields and operates the sub-fields. The drivers apply plural sustain discharge pulses having a first voltage to the first and second electrodes. The drivers maintain the voltage of the second electrodes to the first voltage while the voltage of the first electrodes is gradually increased or decreased between a second voltage higher than the first voltage and the first voltage.

Description

Plasma display device and driving method thereof {PLASMA DISPLAY DEVICE AND DRIVING METHOD THEREOF}

1 is a drive waveform diagram in a sustain period of a plasma display device according to the prior art.

2 is a diagram illustrating a plasma display device according to an exemplary embodiment of the present invention.

3 is a diagram illustrating driving waveforms of the plasma display device according to an exemplary embodiment of the present invention.

4 is an enlarged view of a driving waveform in a sustain period of a plasma display device according to an exemplary embodiment of the present invention.

The present invention relates to a plasma display device and a driving method thereof.

Plasma display devices are flat display devices that display characters or images using plasma generated by gas discharge, and dozens to millions or more of pixels are arranged in a matrix form according to their size.

In a typical plasma display device driving method, one frame is divided into a plurality of subfields, and a gray level is expressed by a combination of subfields. Each subfield consists of a reset period, an address period, and a sustain period.

The reset period serves to erase the wall charge state of the previous sustain discharge and to set up wall charge in order to stably perform the next address discharge.

The address period is a period during which the wall charges are accumulated in the cells that are turned on by selecting cells that are turned on and cells that are not turned on in the panel.

The sustain period is a period in which discharge for actually displaying an image on the addressed cells is performed.

1 is a drive waveform diagram in a sustain period of a plasma display device according to the prior art. In FIG. 1, only the driving waveforms applied to the X electrode and the Y electrode in the sustain period of one subfield are shown.

As shown in Fig. 1, in the sustain period, a sustain discharge pulse having alternating Vs voltage and 0V voltage is applied to the X electrode and the Y electrode, and the phase of the sustain discharge pulse applied to the X electrode and the Y electrode is reversed. In this way, the voltage difference between the X electrode and the Y electrode alternates between the Vs voltage and the -Vs voltage.

At this time, if a predetermined wall voltage is formed between the X electrode and the Y electrode in the address period, the discharge is caused by the voltage difference Vs and the wall voltage applied to the two electrodes. The discharge causes the wall voltage at the two electrodes to change to the opposite polarity, and the discharge occurs again by the voltage difference (-Vs) of the opposite polarity applied to the two electrodes. This process is repeated the number of times corresponding to the weight indicated by the subfield to display the image.

At this time, as shown in FIG. 1, the period of the voltage of the X electrode changes from Vs voltage to 0V, or from 0V to Vs voltage, and the voltage of the Y electrode changes from the V electrode voltage to Vs voltage to 0V, or from 0V to Vs voltage. The changing periods do not overlap in time. At this time, as shown in the optical waveform, the erase discharge d2 occurs when the voltage of the X electrode changes from the Vs voltage to the 0V voltage, or the voltage of the Y electrode changes from the Vs voltage to the 0V voltage, and between the electrodes by the erase discharge. Reduces wall charges that accumulate on the floor. Therefore, after the erase discharge d2 is generated by changing the voltage of the X electrode or the Y electrode from the voltage Vs to 0V, the voltage of the remaining electrodes is increased from 0V to the voltage Vs to generate the main discharge d1.

However, the wall charges accumulated on the electrodes are lost by the erasure discharge d2, and the magnitude of the light waveform of the main discharge d1 becomes weak.

In particular, when the magnitude of the light waveform of the last sustain discharge pulse is weak in the sustain period, the amount of wall charges accumulated on the electrode is reduced, and subsequent reset discharge of the next subfield may not occur stably.

Accordingly, an object of the present invention is to provide a plasma display device and a driving method thereof which stably generate sustain discharge by preventing erasing discharge in the last sustain discharge pulse.

According to one aspect of the present invention for achieving the above object, there is provided a plasma display device. The plasma display device includes a plasma display panel including a plurality of first electrodes, a plurality of second electrodes, and a plurality of third electrodes formed to intersect the plurality of first and second electrodes; A controller for controlling one frame to be divided into a plurality of subfields; And a driving unit alternately applying a plurality of sustain discharge pulses having a first voltage to the plurality of first electrodes and the plurality of second electrodes in the sustain period. In this case, the driving unit is configured to apply voltages of the plurality of first electrodes when applying the first group of sustain discharge pulses including the last sustain discharge pulse to the plurality of first electrodes among the plurality of sustain discharge pulses. After gradually increasing from the second voltage lower than the first voltage to the first voltage, the voltage of the plurality of second electrodes is gradually lowered from the first voltage to the second voltage.

According to another feature of the present invention, there is provided a method of driving a plasma display device including a plurality of first electrodes, a plurality of second electrodes, and a plurality of third electrodes formed to intersect the plurality of first and second electrodes. Is provided. In the driving method, when the first sustain discharge pulse including the last sustain discharge pulse is applied to the plurality of first electrodes in the sustain period, the voltages of the plurality of first electrodes are changed from the first voltage to the first voltage. Gradually raising to a second voltage higher than the voltage; And gradually lowering the voltages of the plurality of second electrodes from the second voltage to the first voltage.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention. Like parts are designated by like reference numerals throughout the specification.

In addition, the wall charge referred to in the present invention refers to a charge formed close to each electrode on the wall of the cell (eg, the dielectric layer). And the wall charge is not actually in contact with the electrode itself, but is described here as "formed", "accumulated" or "stacked" on the electrode. In addition, the wall voltage refers to the potential difference formed in the wall of the cell by the wall charge.

Hereinafter, a plasma display device and a driving method thereof according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram illustrating a plasma display device according to an exemplary embodiment of the present invention.

As shown in FIG. 2, a plasma display device according to an exemplary embodiment of the present invention includes a plasma display panel 100, a controller 200, an address electrode driver 300, a scan electrode driver 400, and a sustain electrode driver 500. It includes.

The plasma display panel 100 includes a plurality of address electrodes A1 to Am extending in the column direction, and a plurality of sustain electrodes X1 to Xn and scan electrodes Y1 to Yn extending in pairs in the row direction. Include. The sustain electrodes X1 to Xn are formed corresponding to the scan electrodes Y1 to Yn, and generally have one end connected to each other in common. The plasma display panel 100 includes a substrate (not shown) on which the sustain and scan electrodes X1 to Xn and Y1 to Yn are arranged, and a substrate (not shown) on which the address electrodes A1 to Am are arranged. . The two substrates are disposed to face each other with the discharge space therebetween so that the scan electrodes Y1 to Yn and the address electrodes A1 to Am and the sustain electrodes X1 to Xn and the address electrodes A1 to Am are orthogonal to each other. At this time, the discharge space at the intersection of the address electrodes A1 to Am and the sustain and scan electrodes X1 to Xn and Y1 to Yn forms a discharge cell. The structure of the plasma display panel 100 is an example, and a panel having another structure to which the driving waveform described below may be applied may also be applied to the present invention.

The controller 200 receives an image signal from the outside and outputs an address electrode A driving control signal, a sustain electrode X driving control signal, and a scan electrode Y driving control signal. The controller 200 divides and drives one frame into a plurality of subfields, and each subfield is composed of a reset period, an address period, and a sustain period. At this time, the control unit 200 may apply a pre-scan pulse to the scan electrode Y immediately before the address period according to the temperature of the plasma display panel 100 received from the temperature sensing unit 600 or the ambient temperature of the plasma display panel. Outputs a control signal.

The address electrode driver 300 receives the address electrode A driving control signal from the controller 200 and applies a display data signal for selecting a discharge cell to be displayed to each address electrode.

The scan electrode driver 400 receives the scan electrode Y driving control signal from the controller 200 and applies a driving voltage to the scan electrode Y.

The sustain electrode driver 500 receives the sustain electrode X driving control signal from the controller 200 and applies a driving voltage to the sustain electrode X.

3 is a diagram illustrating driving waveforms of the plasma display device according to an exemplary embodiment of the present invention.

As shown in FIG. 3, in the rising period of the reset period, the voltage of the Y electrode gradually increases from the voltage of Vs to the voltage of Vset while the A electrode and the X electrode are kept at the reference voltage (shown as "0V" in FIG. 2). Is increased. In FIG. 2, the voltage of the Y electrode is shown to increase in the form of a lamp. In this way, while the voltage of the Y electrode is increased, a weak discharge (hereinafter referred to as "weak discharge") occurs between the Y electrode and the X electrode and between the Y electrode and the A electrode, while the negative electrode charge is applied to the Y electrode. Is formed and positive wall charges are formed at the X and A electrodes.

In the falling period of the reset period, while the voltages of the A electrode and the X electrode are maintained at the reference voltage and the Ve voltage, respectively, the voltage of the Y electrode gradually decreases from the Vs voltage to the Vnf voltage. Then, while the voltage of the Y electrode decreases, a weak discharge occurs between the Y electrode and the X electrode, and between the Y electrode and the A electrode, and the negative wall charges formed on the Y electrode and the positive wall charges formed on the X electrode and the A electrode. Is erased. In general, the magnitude of the voltage (Vnf-Ve) is set near the discharge start voltage Vfxy between the Y electrode and the X electrode. As a result, the wall voltage between the Y electrode and the X electrode becomes almost 0 V, whereby a cell that does not have an address discharge in the address period can be prevented from being erroneously discharged in the sustain period.

In the address period, in order to select a discharge cell to be turned on, while a Ve voltage is applied to the X electrode, a scanning pulse having a VscL voltage is sequentially applied to the plurality of Y electrodes. At this time, the Va voltage is applied to the A electrode passing through the discharge cell to be selected from among the plurality of discharge cells to which the VscL voltage is applied by the Y electrode. Then, an address discharge occurs between the A electrode to which the Va voltage is applied and the Y electrode to which the VscL voltage is applied, and the Y electrode to which the VscL voltage is applied, and the X electrode to which the Ve voltage is applied, thereby causing a positive wall charge, A, to the Y electrode. Negative wall charges are formed on the electrode and the X electrode, respectively. Here, the VscL voltage may be set at a level equal to or lower than the Vnf voltage. The VscH voltage higher than the VscL voltage is applied to the Y electrode to which the VscL voltage is not applied, and the reference voltage is applied to the A electrode of the discharge cell that is not selected.

In the sustain period, a sustain discharge pulse having alternating Vs voltages and 0V voltages is applied to the Y electrode and the X electrode in the opposite phase to generate a sustain discharge between the Y electrode and the X electrode. Thereafter, the process of applying the sustain discharge pulse of the Vs voltage to the Y electrode and the process of applying the sustain discharge pulse of the Vs voltage to the X electrode are repeated the number of times corresponding to the weight indicated by the corresponding subfield.

Hereinafter, a driving waveform capable of preventing erasing discharge of the last sustain discharge pulse will be described with reference to FIG. 4.

4 is an enlarged view of a driving waveform in a sustain period of a plasma display device according to an exemplary embodiment of the present invention.

Although only driving waveforms of the X electrode and the Y electrode are shown in FIG. 4, the A electrode is biased at 0 V in the sustain period.

As shown in FIG. 4, the sustain period of the plasma display device according to the exemplary embodiment of the present invention is divided into a first sustain period and a second sustain period.

The first sustain period represents a period in which the voltage of the X electrode or the Y electrode drops from the Vs voltage to 0 V, and then the voltage of the remaining Y electrode or the X electrode rises from 0 V to the Vs voltage.

The second sustain period is a period including the last sustain discharge pulse. The second sustain period is a period in which the voltage of the X electrode or the Y electrode rises from the voltage of 0 V to the voltage of Vs, and then the voltage of the remaining Y electrode or the X electrode falls from Vs to 0 V. Indicates.

In the first sustain period, as described above, the erase discharge d2 occurs when the voltage of the X electrode or the Y electrode drops from the Vs voltage to the 0V voltage, and then the voltage of the Y electrode or the X electrode, which is the remaining electrode, is 0V. When the voltage rises to Vs, the main discharge d1 is generated.

That is, when the voltage of the X electrode drops to 0 V from the Vs voltage, since the 0 V voltage is already applied to the Y electrode by the previous sustain discharge pulse, the X electrode and the Y electrode have a lower potential than the A electrode, and thus the cathode ( Cathode) and the A electrode is in the anode (Anode) state. This is because the positive and negative wall charges have already accumulated on the A electrode in the address period, so that the X and Y electrodes have lower potentials than the A electrode even when the A electrode is biased to 0V.

The same applies to the case where the opposite voltage is applied to the X electrode and the Y electrode, and thus description thereof will be omitted.

Accordingly, current flows from the A electrode in the anode state to the X or Y electrode in the cathode state, so that a counter discharge occurs, so that the wall charge is self-erasing between the A electrode and the X or Y electrode. Will occur.

As a result, after the erasing discharge d2 has already occurred, when the voltage of the Y or X electrode rises from 0 V to the voltage Vs, the voltage difference between the X electrode and the Y electrode increases, so that the main discharge d1 occurs, but the erase discharge already occurs. Since the wall charge is erased by d2, the magnitude of the light waveform becomes smaller than that of the light waveform in the second sustain period.

On the other hand, in the second sustain period, the voltage of the X or Y electrode rises from 0V to Vs voltage, and then the voltage of the remaining electrode Y or X electrode drops from Vs voltage to 0V voltage, unlike the first sustain period. Erasing discharge does not occur, and d3 which is a main discharge occurs.

Unlike the first sustaining period in which the main discharge occurs when the voltage of the Y or X electrode rises from the 0V voltage to the Vs voltage, in the second sustaining period, when the voltage of the Y or X electrode falls from the Vs voltage to the 0V voltage, Discharge occurs.

That is, in the second sustain period, the voltage of the X or Y electrode is first raised from 0 V to the Vs voltage, so that the X or Y electrode is kept in the anode state as it is, and the A electrode is also kept in the cathode state, and erase discharge occurs. It doesn't work.

That is, when the voltage of the Y electrode rises from 0V to the voltage Vs in the second sustain period, since the voltage Vs is already applied to the X electrode by the previous sustain discharge pulse, both the X electrode and the Y electrode are biased to 0V. It maintains a high potential compared to the A electrode. Therefore, during the period in which the voltage of the Y electrode rises from 0V to the voltage Vs, the cathode and anode states are maintained between the electrodes so that erase discharge does not occur between the A electrode and the X or Y electrode.

Next, the main discharge d3 is generated in the period in which the voltage of the X electrode falls from the voltage Vs to 0V. At this time, since the erase discharge did not occur, there is no amount of wall charges lost and the magnitude of the optical waveform of the main discharge d3 is larger than that of the main discharge d1 in the first sustain period. The same applies to the case where the opposite voltage is applied to the X electrode and the Y electrode, and thus description thereof will be omitted.

That is, according to the embodiment of the present invention, in the first sustain period, the main discharge d1 is generated in the period in which the voltage of the X or Y electrode is increased, but in the second sustain period, the main discharge d1 is generated in the period in which the voltage of the X or Y electrode is decreased. By generating the discharge d3, it is possible to prevent the generation of the erase discharge d2 unlike in the first sustain period.

Therefore, according to the embodiment of the present invention, the last sustain discharge pulse causes strong sustain discharge, so that the reset operation of the following subfield can be stably performed.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

As described above, according to the present invention, erasing discharge can be prevented at the time of applying the last sustain discharge pulse in the plasma display device, and the reset operation of the following subfield can be stably performed.

Claims (10)

A plasma display panel including a plurality of first electrodes, a plurality of second electrodes, and a plurality of third electrodes formed to intersect the plurality of first and second electrodes; A controller for controlling one frame to be divided into a plurality of subfields; And A driving unit configured to alternately apply a plurality of sustain discharge pulses having a first voltage to the plurality of first electrodes and the plurality of second electrodes in a sustain period, The driving unit, When the first group of sustain discharge pulses including the last sustain discharge pulse among the plurality of sustain discharge pulses are applied to the first electrode, the voltage of the first electrode is applied at a second voltage lower than the first voltage. The voltage of the second electrode is maintained at the first voltage while gradually increasing to the first voltage, and the second electrode is gradually lowered from the second voltage to the first voltage. The plasma display device maintains the voltage at the first voltage. The method of claim 1, When a second group of sustain discharge pulses other than the sustain discharge pulses of the first group of the plurality of sustain discharge pulses are applied to the plurality of first electrodes, the voltage of the second electrode is changed from the first voltage. And after lowering to a second voltage, voltages of the plurality of first electrodes are raised from the second voltage to the first voltage. The method of claim 2, The sustain discharge generated by the sustain discharge pulses of the first group is stronger than the sustain discharge generated by the sustain discharge pulses of the second group. The method of claim 3, The width of the sustain discharge pulses of the first group is larger than that of the sustain discharge pulses of the second group. The method of claim 4, wherein And the sustain discharge pulses of the first group are later in time than the sustain discharge pulses of the second group. The method according to any one of claims 1 to 5, And the second voltage is a ground voltage. A method of driving a plasma display device comprising a plurality of first electrodes, a plurality of second electrodes, and a plurality of third electrodes formed to intersect the plurality of first and second electrodes. In the case of applying the first sustain discharge pulse including the last sustain discharge pulse to the plurality of first electrodes in the sustain period, the voltage of the plurality of first electrodes is higher than the first voltage at the first voltage. Gradually raising to a voltage; And And gradually decreasing voltages of the plurality of second electrodes from the second voltage to the first voltage. The method of claim 7, wherein In the case of applying the second sustain discharge pulse to the plurality of first electrodes that is temporally preceding the first sustain discharge pulse in the sustain period, Gradually lowering the voltages of the plurality of second electrodes from the second voltage to the first voltage; And And gradually increasing voltages of the plurality of first electrodes from the first voltage to the second voltage. The method of claim 8, And the sustain discharge generated by the sustain discharge pulses of the first group is stronger than the sustain discharge generated by the sustain discharge pulses of the second group. The method according to any one of claims 7 to 9, And the second voltage is a ground voltage.

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