KR20090125474A - Plasma display device and driving method thereof - Google Patents

Abstract

PURPOSE: A plasma display device and a driving method thereof are provided to prevent low discharge and discharge error by reducing a change amount of a wall charge during a scan standby time of an address cycle. CONSTITUTION: A plasma display device includes first electrodes(X1~Xm), second electrodes(Y1~Yn), and discharge cells(110). The second electrodes intersect with the first electrodes. The discharge cells are defined by the first electrodes and the second electrodes. The plasma display device includes a control part(200) and a driving part(300,400,500). The control part divides one selected frame into sub fields, and drives the frame. The sub fields are divided into a first sub field and a second sub field. The driving part discharges the discharge cells during a reset cycle of the first sub field.

Description

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

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

The plasma display device is a display device using a plasma display panel that displays text or an image by using plasma generated by gas discharge. In the plasma display panel, a plurality of discharge cells are arranged in a substantially matrix form.

In general, in a plasma display device, discharge cells are initialized through reset discharge during a reset period of each subfield, and light emitting cells and non-light emitting cells are selected by address discharge during an address period. In the sustain period, the sustain discharge occurs as many times as the number corresponding to the weight of the corresponding subfield in the light emitting cell, thereby displaying an image. At this time, the reset period of some subfields of one frame is the main reset period which causes reset discharge to all the light emitting cells, and the reset period of the remaining some subfields causes reset discharge only in the light emitting cells in which sustain discharge has occurred in the immediately preceding subfield. A secondary reset period is made.

In the auxiliary reset period, the voltage of the scan electrode is increased in the form of a lamp while the address electrode is biased to 0V, and then the voltage of the scan electrode is reduced in the form of a lamp.

After such an auxiliary reset period, in the address period, scanning pulses are sequentially applied to the plurality of electrodes for address discharge. At this time, the scan waiting time becomes long in the discharge cell defined by the scan electrode to which the scan pulse is applied late. In addition, wall charge loss occurs due to the scan waiting time, and the address discharge delay time becomes long, thereby making the address discharge unstable. As a result, a low discharge phenomenon may occur in which the address discharge is weak and the sustain discharge of the light emitting cell is weak.

An object of the present invention is to provide a plasma display device and a driving method thereof capable of stably performing address discharge.

A plurality of first electrodes according to a feature of the present invention for achieving the above object, a plurality of second electrodes extending in a direction crossing the plurality of first electrodes, and defined by the first and second electrodes A method of driving a plasma display device including a plurality of discharge cells, the method comprising: dividing a frame into a plurality of subfields having respective weights, during the reset period of the first subfield among the plurality of subfields; Applying a main reset waveform for resetting and discharging a plurality of discharge cells to an electrode, and during an auxiliary reset period of at least one second subfield of the plurality of subfields, in the sustain period of the immediately preceding subfield to the first electrode; And applying an auxiliary reset waveform for resetting and discharging only the discharge cells discharged sustainably, wherein applying the auxiliary reset waveform comprises: Gradually increasing the voltage of the first electrode from a second voltage to a third voltage with a first voltage applied to a second electrode, and during the second period after the first period, the second electrode Gradually decreasing a voltage of the first electrode from a fifth voltage to a sixth voltage in a state in which a fourth voltage lower than the first voltage is applied to the fourth voltage.

According to another aspect of the present invention, a plasma display device includes a plurality of first electrodes, a plurality of second electrodes extending in a direction crossing the plurality of first electrodes, and a plurality of first electrodes defined by the plurality of first and second electrodes. A discharge cell of the control unit, a control unit configured to control one frame to be divided into a plurality of subfields having respective weights, and to reset and discharge the plurality of discharge cells during a reset period of a first subfield among the plurality of subfields, And a driving unit configured to reset discharge only the discharge cells sustained and discharged in the first subfield during the auxiliary reset period of at least one second subfield of the plurality of subfields, wherein the driving unit is a first period of the auxiliary reset period. While the first voltage is applied to the second electrode for a while, the voltage of the first electrode is gradually increased from the second voltage to the third voltage, In the state where a fourth voltage lower than the first voltage is applied to the second electrode during the second period after the interval, the voltage of the first electrode is gradually decreased from the fifth voltage to the sixth voltage.

According to another aspect of the invention, a plurality of first electrodes and a plurality of second electrodes, a plurality of third electrodes extending in a direction crossing the plurality of first and second electrodes, and the first to third electrodes A driving method of a plasma display device including a plurality of discharge cells defined by: A first voltage is applied to the third electrode and lower than the first voltage to the second electrode during a first period of a reset period. Gradually increasing the voltage of the first electrode from the third voltage to a fourth voltage in a state where a second voltage is applied, and during the second period after the first period of the reset period, the third electrode While applying a fifth voltage lower than the first voltage and applying a sixth voltage higher than the second voltage to the second electrode, the voltage of the first electrode is gradually increased from the seventh voltage to the eighth voltage. Reducing by Includes, a difference between the fourth voltage and the second voltage is less than the difference between the eighth voltage and the sixth voltage.

As described above, according to the present invention, it is possible to minimize the wall charge formation in the auxiliary reset period and to reduce the amount of change of the wall charge during the scan waiting time of the address period, thereby preventing the low discharge and the false discharge phenomenon.

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 for simplicity of explanation, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, except to exclude other components unless otherwise stated.

In addition, the wall charge in the present invention refers to a charge formed close to each electrode on the wall of the discharge cell (for example, 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, a wall voltage refers to the potential difference formed in the wall of a discharge cell by 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.

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

As shown in FIG. 1, a plasma display device according to an exemplary embodiment of the present invention may include a plasma display panel 100, a controller 200, an address electrode driver 300, a sustain electrode driver 400, and a scan electrode driver 500. ).

The plasma display panel 100 includes a plurality of address electrodes (hereinafter referred to as "A electrodes") A1-Am extending in the column direction, and a plurality of sustain electrodes extending in pairs with each other in the row direction (hereinafter, " X electrodes "(X1-Xn) and scan electrodes (hereinafter referred to as" Y electrodes ") (Y1-Yn). In general, the X electrodes X1 to Xn are formed to correspond to the respective Y electrodes Y1 to Yn, and the X electrodes X1 to Xn and the Y electrodes Y1 to Yn are used to display an image in a sustain period. Perform the display operation. The Y electrodes Y1-Yn and the X electrodes X1-Xn are arranged to be orthogonal to the A electrodes A1-Am. At this time, the discharge space at the intersection of the A electrodes A1-Am and the X and Y electrodes X1-Xn and Y1-Yn forms a discharge cell (hereinafter referred to as a "cell") 110. The structure of the plasma display panel 100 is an example, and other structures may also be applied to the present invention.

The controller 200 receives an image signal from the outside and outputs an A electrode driving control signal, an X electrode driving control signal, and a Y electrode driving control signal. The controller 200 divides and drives one frame into a plurality of subfields, and each subfield includes a reset period, an address period, and a sustain period when expressed as a temporal change in operation.

The reset period is a period for initializing the plurality of cells 110, and the address period is a period for selecting light emitting cells and non-light emitting cells among the plurality of cells 110. The sustain period is a period in which sustain discharge is caused in the light emitting cells by the number of times corresponding to the weight of the corresponding subfield. At this time, the gray level of each cell is determined by the combination of the weights of the subfields to emit light. Meanwhile, the reset period may be removed in some subfields of the plurality of subfields.

The control unit 200 converts the image signal into subfield data indicating whether light is emitted in each subfield, and controls the A electrode driving control signal and the Y electrode driving control according to the converted subfield data and the number of sustain discharges in each subfield. Signal and an X electrode drive control signal.

The address electrode driver 300 receives the A electrode driving control signal from the controller 200 and applies a display data signal for selecting a discharge cell or a non-light emitting cell to each A electrode.

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

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

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

As shown in FIG. 2, one frame may include a plurality of subfields having respective weights. In FIG. 2, one frame is illustrated as having 11 subfields SF1-SF11 having weights of 1, 2, 3, 5, 8, 12, 18, 19, 40, 59, and 78, respectively. SF1-SF11) consists of a reset period, an address period, and a sustain period. At this time, the reset period of some of the subfields among the plurality of subfields may be a main reset period, and the reset period of the remaining some subfields of the plurality of subfields may be an auxiliary reset period. In FIG. 2, the reset period of the first subfield SF1 is shown as the main reset period, and the reset period of the remaining subfields SF2-SF11 is shown as the auxiliary reset period.

3 is a diagram illustrating driving waveforms of the plasma display device according to an exemplary embodiment of the present invention. In FIG. 3, only driving waveforms of two subfields SF1 and SF2 among the plurality of subfields are shown for convenience of description, and will be described with reference to a cell formed by one X electrode, a Y electrode, and an A electrode.

As shown in FIG. 3, in the main reset period of the subfield SF1, the address electrode driver 300 and the sustain electrode driver 400 respectively set the A electrode and the X electrode to a reference voltage (0 V voltage in FIG. 3). The scan electrode driver 500 gradually increases the voltage of the Y electrode from the voltage (VscH-VscL) to the voltage Vset. In FIG. 3, the voltage of the Y electrode is increased in the form of a lamp. Then, 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, and a negative wall charge is applied to the Y electrode. And a positive wall charge is formed on the X and A electrodes. At this time, the Vset voltage may be set higher than the discharge start voltage between the X electrode and the Y electrode so that discharge occurs in all cells. In this case, a voltage VscH-VscL + Vs corresponding to the sum of the Vs voltage and the (VscH-VscL) voltage applied to the Y electrode in the sustain period may be used as the Vset voltage. It is also possible to use other voltages, for example Vs voltages instead of the (VscH-VscL) voltages.

Subsequently, the sustain electrode driver 400 biases the X electrode to the Ve voltage, and the scan electrode driver 500 gradually decreases the voltage of the Y electrode from the 0V voltage to the Vnf voltage. In FIG. 3, the voltage of the Y electrode is reduced in the form of a lamp. 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, so that the negative wall charge formed on the Y electrode and the positive wall formed on the X electrode and the A electrode The charge is erased. At this time, the Ve voltage and the Vnf voltage may be set such that the wall voltage between the Y electrode and the X electrode is close to 0 V so that the sustain discharge does not occur in the cell that is not selected in the address period. That is, the (Ve-Vnf) voltage may be set to about the discharge start voltage between the Y electrode and the X electrode.

Next, in the address period, the scan electrode driver 500 and the address electrode driver 300 are connected to the Y electrode and the A electrode to select the light emitting cell while the sustain electrode driver 400 maintains the voltage of the X electrode at the Ve voltage. A scan pulse having a VscL voltage and an address pulse having a Va voltage are applied, respectively. The unselected Y electrode is biased to a VscH voltage higher than the VscL voltage, and a reference voltage is applied to the A electrode of the non-light emitting cell. In this case, the VscL voltage may be equal to or lower than the Vnf voltage.

Specifically, in the address period, the scan electrode driver 500 and the address electrode driver 300 apply the scan pulse to the Y electrode (Y1 in FIG. 1) of the first row while applying the scan pulse to the A electrode located in the light emitting cell of the first row. Apply an address pulse. Then, an address discharge occurs between the Y electrode of the first row and the A electrode to which the address pulse is applied, thereby forming positive wall charges on the Y electrode and negative wall charges on the A and X electrodes, respectively. Subsequently, the scan electrode driver 500 and the address electrode driver 300 apply an address pulse to the A electrode positioned in the light emitting cell of the second row while applying a scan pulse to the Y electrode (Y2 in FIG. 1) of the second row. do. Then, discharge occurs in the cell formed by the Y electrode of the second row and the A electrode to which the address pulse is applied, thereby forming wall charges in the cell. Similarly, the scan electrode driver 500 and the address electrode driver 300 apply an address pulse to the A electrode positioned in the light emitting cell while sequentially applying scan pulses to the Y electrodes of the remaining rows to form wall charges.

Subsequently, in the sustain period, the scan electrode driver 500 applies a sustain pulse having the high level voltage (Vs in FIG. 3) and the low level voltage (0 V in FIG. 3) to the Y electrode corresponding to the weight of the corresponding subfield. Apply the number of times. The sustain electrode driver 400 applies a sustain pulse to the X electrode in a phase opposite to that of the sustain pulse applied to the Y electrode. In this way, the voltage difference between the Y electrode and the X electrode alternates between the Vs voltage and the -Vs voltage, whereby the sustain discharge is repeatedly generated a predetermined number of times in the light emitting cell.

In the sustain period of the subfield SF1 and the auxiliary reset period of the subfield SF2, the sustain electrode driver 400 biases the X electrode to the reference voltage, and the address electrode driver 300 biases the A electrode higher than the 0V voltage. The voltage is biased, and the scan electrode driver 500 gradually increases the voltage of the Y electrode from the voltage of 0V to the voltage of Vset1. At this time, if the Va voltage used in the address period is used as a voltage higher than the 0V voltage, it is not necessary to add a separate power supply for supplying the Va voltage. In addition, the voltage of the Y electrode may be increased from the voltage higher than the 0V voltage to the Vset1 voltage instead of the 0V voltage.

On the other hand, after the sustain discharge occurs because the Vs voltage is applied to the X electrode and the 0 V voltage is applied to the Y electrode in the sustain period of the subfield SF1, the auxiliary reset period of the susfield SF2 starts. That is, the auxiliary reset period is performed in a state where positive wall charges are formed at the Y electrode and the A electrode, and negative wall charges are formed at the X electrode. While the voltage of the Y electrode is gradually increasing at the auxiliary reset time, if the sum of the wall voltage and the Y electrode voltage between the X electrode and the Y electrode exceeds the discharge start voltage between the X electrode and the Y electrode, A weak discharge occurs so that the positive wall charges formed on the Y electrode are erased to form a negative wall charge, and the negative wall charges formed on the X electrode are erased to form a positive wall charge. If the sum of the wall voltage between the Y electrode and the A electrode and the Y electrode voltage exceeds the discharge start voltage between the A electrode and the Y electrode while the voltage of the Y electrode is increased, the weak discharge occurs between the Y electrode and the A electrode. Thus, the positive wall charges formed on the Y electrode are erased to form negative wall charges, and the positive wall charges are formed on the A electrode.

The voltage difference between the Y electrode and the A electrode is smaller than the voltage difference when a reference voltage (0 V in FIG. 3) is applied to the A electrode. Therefore, the amount of (+) wall charges formed on the A electrode when the A electrode is biased with Va voltage is relatively smaller than the amount of the (+) wall charges formed on the A electrode when the A electrode is biased with the reference voltage. .

At this time, since the reset period of the subfield SF2 is an auxiliary reset period, the voltage Vset1 is set so that reset discharge does not occur when sustain discharge does not occur in the immediately preceding subfield SF1. However, the cells in which sustain discharge has not occurred in the immediately preceding subfield SF1 have no wall discharge, and therefore have a wall charge state set in the reset period of the immediately preceding subfield SF1. Therefore, if the difference between the voltage Vset1 and the voltage (0V) applied to the X electrode, that is, the voltage Vset1 is set to a voltage lower than approximately the discharge start voltage between the X electrode and the Y electrode, sustain discharge does not occur in the immediately preceding subfield SF1. Reset discharge may not occur in an unused cell. As described above, since the discharge start voltages of the X electrode and the Y electrode are approximately similar to the (Ve-Vnf) voltage, the Vset1 voltage can be set below the (Ve-Vnf) voltage.

Subsequently, in the auxiliary reset period, the sustain electrode driver 400 and the address electrode driver 300 respectively apply the Ve voltage and the reference voltage to the X electrode and the A electrode, respectively, and the scan electrode driver 500 sets the Y electrode voltage to 0V. Incrementally decreases from voltage to Vnf. The voltage of the Y electrode can be gradually decreased from the voltage Vset1 to the voltage Vnf. However, in this case, since the reset period becomes long, it can be reduced from the voltage at which discharge does not start, for example, the voltage of 0V. Then, while the voltage of the Y electrode decreases, a weak discharge occurs between the Y electrode and the X electrode of the light emitting cell and between the Y electrode and the A electrode of the light emitting cell, and thus the negative wall charge and the light emitting cell formed on the Y electrode of the light emitting cell The positive (+) wall charges formed on the X and A electrodes are erased. At this time, by biasing the A electrode to the Va voltage while the voltage of the Y electrode is gradually rising, the positive wall charges formed on the A electrode are reduced, and thus, when the voltage of the Y electrode is gradually decreased, ) The influence of wall charges can be minimized.

Next, in the subfield SF2, light emitting cells and non-light emitting cells are selected through address discharge in the address period, and sustain discharge is performed on the light emitting cells in the sustain period. At this time, since the influence of the (+) wall charges formed on the A electrode in the auxiliary reset period is minimized, the amount of change in the (+) wall charges formed on the A electrode while the address pulse is applied to the A electrode of the light emitting cell during the address period is reduced. Can be. Thus, the positive wall charges formed on the A electrode can affect the address discharge.

As described above, according to the exemplary embodiment of the present invention, the formation of the positive (+) wall charges on the A electrode is minimized during the auxiliary reset period, and the amount of change of the wall charges during the scan waiting time until the address pulse is applied to the scan electrode in the address period is minimized. By making it small, the low discharge and mis-discharge phenomenon can be 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.

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

2 is a diagram schematically illustrating a method of driving 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.

Claims (12)

A method of driving a plasma display device comprising a plurality of first electrodes, a plurality of second electrodes extending in a direction crossing the plurality of first electrodes, and a plurality of discharge cells defined by the first and second electrodes. To Dividing a frame into a plurality of subfields having respective weights, Applying a main reset waveform to reset discharge a plurality of discharge cells to the first electrode during a reset period of a first subfield among a plurality of subfields, and Applying an auxiliary reset waveform to reset discharge only the discharge cells sustained and discharged in the sustain period of the immediately preceding subfield to the first electrode during the auxiliary reset period of at least one second subfield of the plurality of subfields; Including; Applying the auxiliary reset waveform, Gradually increasing the voltage of the first electrode from a second voltage to a third voltage with a first voltage applied to the second electrode during a first period, and During the second period after the first period, the voltage of the first electrode is gradually decreased from the fifth voltage to the sixth voltage while a fourth voltage lower than the first voltage is applied to the second electrode. And driving the plasma display device. The method of claim 1, The plasma display device further includes a plurality of third electrodes configured to perform a display operation together with the plurality of first and second electrodes. During the period in which the voltage of the first electrode is gradually increased, And a difference between voltages applied to the first electrode and the second electrode is smaller than a difference between voltages applied to the first electrode and the third electrode. The method of claim 2, The increasing includes applying the seventh voltage to the third electrode, The reducing may include applying an eighth voltage higher than the seventh voltage to the third electrode. The method of claim 3, And the difference between the third voltage and the seventh voltage is equal to or less than the difference between the sixth voltage and the eighth voltage. The method according to any one of claims 1 to 4, And wherein the discharge cells are not discharged in the auxiliary reset period when the discharge cells are non-light emitting cells in the first subfield immediately before the auxiliary reset period. The method according to any one of claims 1 to 4, And applying a scan voltage and the first voltage to the first electrode and the second electrode of a discharge cell to be selected as the light emitting cell in the address period of the second subfield, respectively. The method according to any one of claims 1 to 4, Applying the auxiliary reset waveform, And reducing the voltage of the first electrode from the third voltage to the second voltage. A plurality of first electrodes, A plurality of second electrodes extending in a direction crossing the plurality of first electrodes, A plurality of discharge cells defined by the plurality of first and second electrodes, A controller for controlling one frame to be divided and driven into a plurality of subfields having respective weights, and Resetting and discharging the plurality of discharge cells during a reset period of a first subfield among the plurality of subfields, and sustaining in the first subfield during an auxiliary reset period of at least one second subfield of the plurality of subfields. A driving unit configured to reset discharge only discharged discharge cells, The driving unit, In the state where the first voltage is applied to the second electrode during the first period of the auxiliary reset period, the voltage of the first electrode is gradually increased from the second voltage to the third voltage, and the second after the first period. And gradually reduce the voltage of the first electrode from the fifth voltage to the sixth voltage while applying a fourth voltage lower than the first voltage to the second electrode. The method of claim 8, The driving unit, And a scan voltage and the first voltage are applied to the first electrode and the second electrode of a discharge cell to be selected as the light emitting cell, respectively, in the address period of the second subfield. The method of claim 9, The plasma display device further includes a plurality of third electrodes configured to perform a display operation together with the plurality of first and second electrodes. The driving unit, Applying the seventh voltage to the third electrode during the first period, and applying an eighth voltage higher than the seventh voltage to the third electrode during the second period, The difference between the third voltage and the seventh voltage is less than or equal to the difference between the sixth voltage and the eighth voltage. A plurality of first electrodes and a plurality of second electrodes, a plurality of third electrodes extending in a direction crossing the plurality of first and second electrodes, and a plurality of discharge cells defined by the first to third electrodes In the method of driving a plasma display device comprising: During the first period of the reset period, in a state in which a first voltage is applied to the third electrode and a second voltage lower than the first voltage is applied to the second electrode, the voltage of the first electrode is changed to the third voltage. Gradually increasing from to the fourth voltage, and During a second period after the first period of the reset period, a fifth voltage lower than the first voltage is applied to the third electrode, and a sixth voltage higher than the second voltage is applied to the second electrode. Gradually reducing the voltage of the first electrode from a seventh voltage to an eighth voltage Including; And a difference between the fourth voltage and the second voltage is equal to or less than a difference between the eighth voltage and the sixth voltage. The method of claim 11, And applying a scan voltage and the first voltage to the first electrode and the third electrode of a discharge cell to be selected as the light emitting cell, respectively, in the address period after the reset period.

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