KR100778505B1 - Plasma display device and driving method thereof - Google Patents

Abstract

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

According to the present invention, the number of power sources can be reduced by floating the voltage of the sustain electrode in the reset falling period from the sustain discharge pulse voltage to initialize the wall charge suitable for addressing.

 PDP, Floating, Power, Bias

Description

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

1 is a driving waveform diagram 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 driving waveform diagram of a plasma display device according to an exemplary embodiment of the present invention.

The present invention relates to a plasma display device, and more particularly, to a power supply device for supplying a voltage for driving a plasma display device.

A plasma display device is a display device that displays characters or images by using plasma generated by gas discharge, and tens to millions or more pixels (discharge cells) are arranged in a matrix form according to their size. The plasma display device is classified into a direct current type and an alternating current type according to the shape of a driving voltage waveform to be applied and the structure of a discharge cell.

In the panel of the DC plasma display device, since the electrode is exposed to the discharge space as it is, the current flows in the discharge space while the voltage is applied, and for this purpose, a resistance for limiting the current must be made. On the other hand, the panel of the AC plasma display device has an advantage that the electrode is covered with a dielectric layer, so that the current is limited by the formation of a natural capacitance component and the life is longer than that of the DC type because the electrode is protected from the impact of ions during discharge.

Such a plasma display device typically supplies various high voltages required for plasma discharge, for example, a sustain discharge voltage Vs, an address voltage Va, a reset voltage Vset, a scan voltage, and the like to a driving circuit. That is, a power supply device for supplying a low voltage to an image processing unit, a fan, an audio unit, a control circuit unit, and the like is provided.

Hereinafter, a driving waveform applied to the address electrodes A1 to Am, the sustain electrodes X1 to Xn, and the scan electrodes Y1 to Yn in each subfield will be described with reference to FIG. 1. The following description will be made based on the discharge cells formed by one address electrode, sustain electrode and scan electrode.

1 is a driving waveform diagram of a plasma display device according to the present invention. In FIG. 1, only one subfield of a plurality of subfields is illustrated.

As shown in Fig. 1, the subfield includes a reset period, an address period, and a sustain period, and the reset period includes a rising period and a falling period.

First, in the rising period of the reset period of the first subfield, a rising waveform that increases from the Vs voltage to the Vset voltage is applied to the scan electrode Y while the sustain electrode X is maintained at 0V. Then, a weak reset discharge occurs from the scan electrode Y to the address electrode A and the sustain electrode X, respectively, and negative wall charges are accumulated on the Y electrode, and the address electrode A and the sustain electrode X are accumulated. Positive wall charges accumulate at).

In the falling period of the reset period of the first subfield, a falling waveform of decreasing from the voltage Vs to the voltage Vnf is applied to the scan electrode Y while the sustain electrode X is maintained at the Ve voltage.

Next, a scan pulse having a VscL voltage is sequentially applied to the plurality of scan electrodes Y in order to select a cell to be turned on in the address period, and a VscH voltage higher than the VscL voltage is applied to the scan electrode Y to which the VscL voltage is not applied. do. At this time, the Ve voltage is applied to the sustain electrode (X). The VscL voltage may be lower than or equal to the Vnf voltage.

Among the plurality of cells formed by the scan electrode Y to which the VscL voltage is applied, an address pulse having a Va voltage is applied to the address electrode A passing through the cell to be turned on, and the reference voltage (A) is applied to the remaining address electrodes A. 0V) is applied.

Subsequently, in the sustain period of the first subfield, the sustain discharge pulses having the Vs voltage and the reference voltage alternately applied to the scan electrode Y and the sustain electrode X in the opposite phase. That is, the reference voltage (0V) is applied to the sustain electrode (X) when the Vs voltage is applied to the scan electrode (Y), and the reference voltage (V) is applied to the scan electrode (Y) when the Vs voltage is applied to the sustain electrode (X). 0V) is applied.

In order to drive the plurality of subfields as described above, a plasma display device typically supplies various voltages (Vs, Vset, Ve, Va, Vnf, VscH, VscL, etc.) required for plasma discharge to a driving circuit, and further circuit portions. That is, a power supply device for supplying a voltage to an image processing unit, a fan, an audio unit, a control circuit unit, and the like is provided.

However, when a separate power source for generating voltages such as Vs, Ve, and Va, respectively, is provided, the price of the power supply device increases.

An object of the present invention is to provide a plasma display device and a driving method thereof for reducing the number of power sources.

According to one aspect of the present invention for achieving the above object, a plurality of first electrodes and second electrodes, a plurality of third electrodes and a plurality of discharge cells formed to intersect the plurality of first and second electrodes A method of driving a plasma display device is provided. The driving method includes the steps of: gradually decreasing the voltages of the plurality of first electrodes from a first voltage to a second voltage in a falling period of a reset period; In a portion of the falling period of the reset period, floating the plurality of second electrodes to gradually drop from a third voltage to a fourth voltage; Selecting a discharge cell to be turned on from among the plurality of discharge cells while biasing the plurality of second electrodes to the third voltage in an address period; In the sustain period, alternately applying the third voltage to the plurality of first and second electrodes.

According to another aspect of the present invention, a plasma display device includes a plasma display panel including a plurality of first electrodes and a plurality of second electrodes; A controller for controlling one frame to be divided into a plurality of subfields; And in a reset period, in some of the first periods of gradually lowering the voltages of the plurality of first electrodes from the first voltage to the second voltage, by floating the plurality of second electrodes to form a fourth at a third voltage. Selects a discharge cell to be turned on in a state in which the plurality of second electrodes are biased to the third voltage in an address period, and a sustain discharge pulse having the third voltage level in the sustain period; And a driving unit applied to the plurality of first and second electrodes.

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.

A plasma display device and a driving method thereof according to an exemplary embodiment of the present invention will now 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. And a power supply unit 600.

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 X electrodes X1 to Xn are formed corresponding to the respective Y electrodes Y1 to Yn, and generally have one end connected in common to each other. 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 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 controller 200 receives an image signal from the outside and outputs an address 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.

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

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.

The power supply unit 600 supplies power required for driving the plasma display device to the control unit 200 and the respective driving units 300, 400, and 500.

Hereinafter, in the exemplary embodiment of the present invention, a method of driving the plasma display device using the Vs power source without using the Ve power source will be described.

Hereinafter, a driving waveform applied to the address electrodes A1 to Am, the sustain electrodes X1 to Xn, and the scan electrodes Y1 to Yn in each subfield will be described with reference to FIG. 3. The following description will be made based on the discharge cells formed by one address electrode, sustain electrode and scan electrode.

3 is a driving waveform diagram of a plasma display device according to an exemplary embodiment of the present invention. In FIG. 3, only one subfield of the plurality of subfields is illustrated.

As shown in Fig. 3, the subfield consists of a reset period, an address period and a sustain period, and the reset period consists of a rising period and a falling period.

In the rising period of the reset period, the voltage of the scan electrode Y is gradually increased from the voltage Vs to the voltage Vset while maintaining the address electrode A at the reference voltage (0 V in FIG. 4). In FIG. 3, the voltage of the scan electrode Y is increased in the form of a lamp. Weak discharge (hereinafter referred to as "weak discharge") between scan electrode Y and sustain electrode X and between scan electrode Y and address electrode A while the voltage of scan electrode Y is increasing. As this occurs, negative wall charges are formed on the scan electrode Y, and positive wall charges are formed on the sustain electrode X and the address electrode A. FIG. When the voltage of the electrode gradually changes as shown in FIG. 3, a weak discharge occurs in the cell, and the wall charge is formed so that the sum of the voltage applied from the outside and the wall voltage of the cell maintains the discharge start voltage state. In the reset period, since the state of all cells must be initialized, the voltage Vset is high enough to cause a discharge in the cells of all conditions. In addition, the voltage Vs is generally the same as the voltage applied to the scan electrode Y in the sustain period, and is lower than the discharge start voltage Vfxy between the scan electrode Y and the sustain electrode X.

Subsequently, in the falling period of the reset period, the voltage of the scan electrode Y is gradually reduced from the voltage Vs to the voltage Vnf which is negative while the sustain electrode X is maintained at the voltage Vs. Then, the voltage of the sustain electrode X is floated in a part of the period in which the voltage applied to the scan electrode Y falls, and a voltage that is continuously lowered from the voltage Vs to the voltage Vc is applied.

Then, while the voltage of the scan electrode Y decreases, a weak discharge occurs between the scan electrode Y and the sustain electrode X and between the scan electrode Y and the address electrode A, and thus the scan electrode Y The negative wall charges formed and the positive wall charges formed on the sustain electrode X and the address electrode A are erased.

At this time, the magnitude of the voltage (Vnf-Vc) is set near the discharge start voltage Vfxy between the scan electrode Y and the sustain electrode X. 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. Since the address electrode A is maintained at the reference voltage, the wall voltage between the Y electrode and the A electrode is determined by the level of the Vnf voltage.

On the other hand, in the case where a large amount of wall charges are formed between the scan electrode Y and the sustain electrode X after the sustain discharge of the previous subfield is completed, especially when the number of sustain discharge pulses of the previous subfield is large, In the falling period, the time at which the sustain electrode X is floated is delayed to eliminate wall charges as much as possible. That is, the voltage difference between the scan electrode Y and the sustain electrode X increases during the period where the voltage of the scan electrode Y decreases and the voltage of the sustain electrode X maintains the voltage Vs, thereby causing weak discharge. The wall charges accumulated on the scan electrode Y and the sustain electrode X are erased. At this time, when the voltage of the sustain electrode X is floated, the voltage difference between the scan electrode Y and the sustain electrode X is kept constant so that the wall charge is no longer erased.

On the other hand, when the wall charge is less formed between the scan electrode Y and the sustain electrode X after the sustain discharge of the previous subfield is finished, as shown by the dotted line, the sustain electrode X is in the falling period of the reset period. The floating point is advanced earlier than when a large amount of wall charges is accumulated to eliminate a small amount of wall charges.

That is, as shown in FIG. 3, the time at which the voltage of the sustain electrode X is floated is set to a faster time than when the wall charges are accumulated, so that the wall charges in a state suitable for addressing are maintained. At this time, the voltage drops to the voltage Vc 'which is a level lower than the voltage Vc.

Therefore, unlike FIG. 1, even when the Ve voltage is not used in the reset falling period, the wall charge suitable for the addressing may be initialized by plotting from the Vs voltage to the Vc voltage.

In addition, the addressing operation may be performed more efficiently by adjusting the amount of wall charge canceling according to the wall charge state of the previous subfield.

Next, to select a cell to be turned on in the address period, a scan pulse having a VscL 'voltage and an address pulse having a Va' voltage are applied to the scan electrode Y and the address electrode A, respectively. The unselected scan electrode Y is biased to a VscH 'voltage higher than the VscL' voltage, and a reference voltage is applied to the address electrode A of the cell that is not turned on. Then, address discharge is caused by the difference between the address voltage Va 'and the scan voltage VscL' and the wall charges formed in the address electrode A and the scan electrode Y. As a result, (+) wall charges are formed on the scan electrode (Y) and (-) wall charges are formed on the sustain electrode (X). In addition, a negative wall charge is also formed on the address electrode A. FIG.

At this time, the sustain electrode X is biased to the Vs voltage which is at a level higher by Vb than the Ve voltage to reduce the number of power supplies. Therefore, in the address period, the VscH 'voltage at the level higher by Vb voltage than the VscH voltage is applied to the scan electrode Y, and the VscL' voltage at the level higher by Vb voltage than the VscL voltage.

That is, by maintaining the voltage difference between the scan electrode Y and the sustain electrode X in the address period at the same level as in Fig. 1, the occurrence of sustain discharge in the discharge cells not selected in the sustain period is prevented.

Similarly, the voltage difference between the scan electrode Y and the address electrode A is applied to the address electrode A by applying a Va 'voltage, which is a level higher by Vb than the Va voltage, to the cell to be turned on. In this way, a sufficient amount of positive wall charges and negative wall charges are accumulated between the scan electrode Y and the address electrode A so that address discharge occurs properly.

Subsequently, in the sustain period, the sustain discharge pulse of the Vs voltage is sequentially applied to the scan electrode Y and the sustain electrode X. FIG. Then, when the wall voltage is formed between the scan electrode Y and the sustain electrode X by the address discharge in the address period, the discharge is generated at the scan electrode Y and the sustain electrode X by the wall voltage and the Vs voltage. Happens. Thereafter, the process of applying the sustain discharge pulse of the Vs voltage to the scan electrode Y and the process of applying the sustain discharge pulse of the Vs voltage to the sustain electrode X are repeated the number of times corresponding to the weight indicated by the corresponding subfield. . When the sustain period ends in this manner, the next subfield starts.

Therefore, in the embodiment of the present invention, the number of Ve power sources can be reduced by floating the voltage of the sustain electrode X at the voltage Vs in the reset falling period to initialize wall charges suitable for addressing.

In the state where the sustain electrode X is biased to the Vs voltage in the address period, the voltage difference between the electrodes is kept constant by adjusting the magnitude of the voltage applied to the scan electrode Y and the address electrode A. In the address period and the sustain period, erroneous discharge and low discharge are prevented.

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, the number of power sources can be reduced in the plasma display device, so that the power supply device can be configured at low cost. In addition, by adjusting the amount of wall charge to be erased in the reset period can be initialized to a state suitable for addressing.

Claims (14)

In a plasma display device including a plurality of first electrodes, a plurality of second electrodes performing a display operation together with the plurality of first electrodes, and a plurality of discharge cells, one frame is divided into a plurality of subfields having respective weights. In a method to be driven, In each of the plurality of subfields, Gradually lowering a voltage of the plurality of first electrodes from a first voltage level to a second voltage level during a falling period of a reset period; Maintaining the voltages of the plurality of second electrodes at a third voltage level during the falling period of the reset period, and then floating the plurality of second electrodes to gradually drop from the third voltage level to a fourth voltage level; Selecting a discharge cell to be turned on from among the plurality of discharge cells while biasing the plurality of second electrodes to the third voltage level in an address period; And In the sustain period, sustain discharge of the discharge cells to be turned on by alternately applying the third voltage level to the plurality of first and second electrodes, The number of the sustain discharges in the first subfield among the plurality of subfields is less than the number of the sustain discharges in the sustain period of the second subfield among the plurality of subfields, and a third immediately after the first subfield. In the plasma display apparatus, a time point at which the plurality of second electrodes float in the fall period of the subfield is earlier than a time point at which the plurality of second electrodes are floated in the fall period of the fourth subfield immediately after the second subfield. Driving method. delete The method of claim 1, And gradually increasing the voltages of the plurality of first electrodes from the first voltage level to a fifth voltage level before the falling period of the reset period. The method of claim 3, And a voltage level difference between the second voltage and the fourth voltage is the same level as the discharge start voltage of the plurality of first and second electrodes. The method of claim 1, And a slope of a voltage at which the plurality of first and second electrodes are gradually dropped in the falling period of the reset period. The method of claim 3, And the first voltage has the same voltage level as the third voltage. A display panel including a plurality of first electrodes and a plurality of second electrodes performing a display operation together with the plurality of first electrodes; A control unit configured to control driving of one frame into a plurality of subfields having respective weights; And In each of the plurality of subfields, The voltages of the plurality of first electrodes are gradually decreased from the first voltage level to the second voltage level during the first period of the reset period of the first subfield, and the voltages of the plurality of second electrodes are reduced to the third voltage level. After maintaining, the plurality of second electrodes are floated to gradually lower from the third voltage level to the fourth voltage level, and the plurality of second electrodes are turned on while being biased to the third voltage level during the address period. And a driving unit configured to sustain discharge the discharge cells to be turned on by applying a sustain discharge pulse having the third voltage level to the plurality of first and second electrodes during a sustain period. When the number of the sustain discharges in the first subfield of the plurality of subfields is less than the number of the sustain discharges in the sustain period of the second subfield of the plurality of subfields, The driver may be configured to display a time point at which the plurality of second electrodes are floated in the first period of the third subfield immediately after the first subfield, in the first period of the fourth subfield immediately after the second subfield. And a plasma display device which floats earlier than the time of floating the second electrode. The method of claim 7, wherein And in the first period, bias the voltage to the third voltage before floating the plurality of second electrodes. The method according to claim 7 or 8, And increasing the voltages of the plurality of first electrodes gradually from the first voltage level to a fifth voltage level before the first period. The method of claim 7, wherein And a slope in which voltages of the plurality of first and second electrodes are gradually decreased in the first period. The method according to claim 7 or 8, And the second voltage is a negative voltage level. The method according to claim 7 or 8, And the first voltage has the same voltage level as the third voltage. delete delete

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