KR100778448B1 - Plasma display and driving method thereof - Google Patents

Abstract

The present invention relates to a plasma display device and a driving method thereof. In the sustain period of the subfield having the main reset period for initializing all the discharge cells, a sustain discharge pulse for maintaining the sustain discharge voltage during the T1 period is applied to the scan electrode and the sustain electrode in the opposite phase. Then, as the T1 period is set smaller, the number of times of applying the sustain discharge pulse in the sustain period increases, thereby increasing the luminance. Further, in the sustain period of the subfield having the auxiliary reset period for initializing the discharge cells displaying the image in the immediately preceding subfield, the scan electrode and the sustain discharge pulse sustaining the sustain discharge voltage for the T2 period longer in time than the T1. It is applied in reverse phase to the electrode. Then, stabilization of sustain discharge can be achieved.

PDP, electrode, wall charge, main reset, auxiliary reset, holding period

Description

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

1 is a schematic plan view of a plasma display device according to an exemplary embodiment of the present invention.

2 illustrates a driving waveform of the plasma display device according to the first embodiment of the present invention.

3 illustrates a driving waveform of the plasma display device according to the second 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 plasma display device, one frame (1TV field) is divided into a plurality of subfields having respective weights, and driven. Each subfield is composed of a reset period, an address period, and a sustain period.

The reset period is a period for initializing the state of each cell in order to smoothly perform an addressing operation on the cell. The address period is an address voltage for a cell (addressed cell) that is turned on to select a cell that is turned on and a cell that is not turned on. It is a period of time to apply an operation to accumulate wall charges. The sustain period is a period in which a discharge for actually displaying an image in the addressed cell is applied by applying a sustain discharge pulse.

In this sustain period, a sustain discharge pulse having a high level voltage (for example, a Vs voltage) and a low level voltage (for example, 0 V) is applied to the scan electrode and the sustain electrode in opposite phases. In this case, first, a Vs voltage is applied to the scan electrode and a 0 V voltage is applied to the sustain electrode, so that sustain discharge occurs between the scan electrode and the sustain electrode, and the sustain discharge causes negative (-) wall charges and ( Wall charges are formed. Hereinafter, the process of applying the sustain discharge pulse to the scan electrode and the sustain electrode is repeated a number of times corresponding to the weight indicated by the corresponding subfield. In general, the sustain discharge pulse is a square wave having a sustain section for maintaining Vs. In this case, the longer the period of maintaining the Vs voltage is, the more stable the sustain discharge is, but the number of sustain discharge pulses that can be applied to one frame is reduced, resulting in a decrease in luminance.

SUMMARY OF THE INVENTION The present invention provides a plasma display device and a driving method thereof capable of increasing the luminance of a plasma display device and ensuring sustain discharge stability.

According to an aspect of the present invention, there is provided a method of driving a plasma display device including a plurality of first electrodes and a plurality of second electrodes performing a display operation together with the plurality of first electrodes. The driving method includes applying a first sustain discharge pulse to the plurality of first electrodes or the plurality of second electrodes in the sustain period of the first subfield having the main reset period for initializing all the discharge cells. Applying a second sustain discharge pulse to the plurality of first electrodes or the plurality of second electrodes in the sustain period of the second subfield having an auxiliary reset period for initializing the discharge cells displaying the image in the subfield. Include. In this case, the first period during which the high level of the second sustain discharge pulse is maintained is longer than the second period during which the high level of the first sustain discharge pulse is maintained.

According to another feature of the present invention, a plasma display device including a plasma display panel and a driver is provided. The plasma display panel includes a plurality of first electrodes and a plurality of second electrodes. The driving unit may be configured to receive a first sustain discharge pulse that maintains a high level voltage for a first period in a sustain period of a first subfield having a main reset period for gradually increasing and decreasing voltages of the plurality of first electrodes. In the sustain period of the second subfield, which is applied to a plurality of first electrodes or the plurality of second electrodes, and has an auxiliary reset period for gradually decreasing the voltage of the plurality of first electrodes, A second sustain discharge pulse that maintains a high level voltage for two periods is applied to the plurality of first electrodes or the plurality of second electrodes.

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, and like reference numerals designate like parts throughout the specification. In addition, when any part of the specification includes a certain component, this means that it may further include other components, except to exclude other components unless otherwise stated.

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

1 is a schematic plan view of 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 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. Include.

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 respective scanning electrodes Y1 to Yn, and display operation for displaying the image in the sustain period between the sustain electrodes X1 to Xn and the scan electrodes Y1 to Yn. Do this. The address electrodes A1 to Am are disposed to be orthogonal to the sustain electrodes X1 to Xn and the scan electrodes Y1 to Yn. At this time, the discharge space at the intersection of the address electrodes A1 to Am, the scan electrodes Y1 to Yn, and the sustain electrodes X1 to Xn forms the cell 12. 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 driving control signal, a sustain electrode driving control signal, and a scan electrode 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 driver 300 receives an address electrode 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 a scan electrode driving control signal from the controller 200 and applies a driving voltage to the scan electrode.

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

Hereinafter, the driving waveforms applied to the address electrodes A1 to Am, the sustain electrodes X1 to Xn, and the scan electrodes Y1 to Yn will be described with reference to FIGS. 2 to 3. For convenience of explanation, a driving waveform applied to an address electrode (hereinafter referred to as an A electrode), a sustain electrode (hereinafter referred to as an X electrode) and a scan electrode (hereinafter referred to as a Y electrode) forming one cell will be described. . In addition, the reset period consisting of the rising period and the falling period is defined as the main reset period, and the reset period consisting only of the falling period is defined as the auxiliary reset period. The main reset period initializes all the discharge cells, and the auxiliary reset period initializes the discharge cells displaying an image in the previous subfield.

2 illustrates a driving waveform of the plasma display device according to the first embodiment of the present invention.

As shown in Fig. 2, in the rising period of the reset period, the voltages of the X and A electrodes are kept at the reference voltage (assuming that the reference voltage is the ground voltage (0 V) in Fig. 2), and the voltage of the Y electrode is Vs voltage. Incrementally increases from to Vset voltage. As such, while the voltage of the Y electrode is increased, a weak discharge occurs between the Y electrode and the X electrode and between the Y electrode and the A electrode, so that a negative wall charge is formed at the Y electrode and a (+) at the X electrode and the A electrode. Wall charges are formed.

In the falling period of the reset period, the voltage of the Y electrode is gradually decreased from the Vs voltage to the Vnf voltage while maintaining the voltages of the A and X electrodes at the reference voltage and the Ve voltage, respectively. 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 (Ve-Vnf) voltage is set near the discharge start voltage Vfxy between the Y electrode and the X electrode. Then, the wall voltage between the Y electrode and the X electrode becomes almost 0 V, and it is possible to prevent the cells which do not have an address discharge in the address period from being misdischarged in the sustain period.

In the address period, in order to select a discharge cell to emit light, a scan pulse having a VscL voltage is sequentially applied to a plurality of Y electrodes while a Ve voltage is applied to the X electrodes. At this time, the Va voltage is applied to the A electrode passing through the discharge cell to emit light among the plurality of discharge cells formed by the Y electrode and the X electrode to which the VscL voltage is applied. Then, 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. Then, positive (+) wall charges are formed on the Y electrode, and negative (-) wall charges are formed on the A electrode and the X electrode. Here, the VscL voltage may be set at a level equal to or lower than the Vnf voltage. A voltage higher than the VscL voltage is applied to the Y electrode to which the VscL voltage is not applied, and a reference voltage is applied to the A electrode of the discharge cell that is not selected.

Meanwhile, in order to perform this operation in the address period, the scan electrode driver 400 selects a Y electrode to which a scan pulse having a VscL voltage is applied among the Y electrodes Y1 to Yn. For example, in the single drive, the Y electrodes can be selected in the order arranged in the vertical direction. When one Y electrode is selected, the address electrode driver 300 selects a discharge cell to be turned on among discharge cells formed by the corresponding Y electrode. That is, the address electrode driver 300 selects a cell to which an address pulse of Va voltage is applied among the A electrodes A1 to Am.

In general, a plasma display panel is driven at 60 frames per second, one frame is divided into eight subfields, and one subfield is driven in a reset period, an address period, and a sustain period in time. Here, as the number of times that the sustain discharge pulse is applied within a limited time (16,67 ms) of one frame increases, the luminance of the plasma display panel increases.

In the sustain period, sustain discharge pulses having a high level voltage (Vs voltage in FIG. 2) and a low level voltage (0V voltage in FIG. 2) are applied to the Y and X electrodes in opposite phases. At this time, in order to increase the luminance of the plasma display panel, a sustain discharge pulse that maintains the Vs voltage is applied during the T1 period, which is a period in which sustain discharge may occur. In this case, the T1 period may be a minimum period in which sustain discharge may occur.

In this case, applying a sustain discharge pulse that maintains the high level voltage to the Y electrode for the period T1, sustain discharge occurs during the period T1, whereby a negative wall charge is formed on the Y electrode and a positive wall charge on the X electrode. Is formed. Subsequently, when a sustain discharge pulse that maintains a high level voltage is applied to the X electrode for a period of T1, sustain discharge occurs during the period T1 to form a positive wall charge on the Y electrode and a negative wall charge on the X electrode. Is formed. Thereafter, the sustain discharge pulses applied to the Y electrode and the X electrode are repeated a number of times corresponding to the weight indicated by the subfield.

In general, in the subfield having the main reset period, since there is a rising period for forming wall charges, more wall charges may be formed in each electrode than in the auxiliary reset period without the rising period for forming wall charges. And the main reset period is formed more priming particles than the auxiliary reset period. Therefore, in the subfield having the main reset period, the sustain discharge occurs stably even when the sustain discharge pulse having the T1 period is applied in the sustain period. However, since there is no period in which the wall charges are formed in the subfield having the auxiliary reset period, as in the rising period of the main reset period, relatively less wall charges are formed than in the subfield having the main reset period. Therefore, when the sustain discharge pulse having the T1 period is applied in the sustain period of the subfield having the auxiliary reset period, the sustain discharge becomes unstable. Hereinafter, a method of stably driving such sustain discharge will be described in detail with reference to FIG. 3.

3 illustrates a driving waveform of the plasma display device according to the second exemplary embodiment of the present invention. In FIG. 3, for convenience, only driving waveforms of the first subfield having the main reset period and the second subfield following the first subfield and having the auxiliary reset period are shown.

As shown in FIG. 3, in the sustain period of the first subfield having the main reset period, the first sustain discharge pulse which maintains the Vs voltage during the T1 period is applied. When a sustain discharge pulse that maintains a high level voltage is applied to the Y electrode for a period of T1, sustain discharge occurs during the period T1 to form a negative wall charge on the Y electrode and a positive wall charge on the X electrode. do. Subsequently, when a sustain discharge pulse that maintains a high level voltage is applied to the X electrode for a period of T1, sustain discharge occurs during the period T1 to form a positive wall charge on the Y electrode and a negative wall charge on the X electrode. Is formed. Thereafter, the sustain discharge pulses applied to the Y electrode and the X electrode are repeated a number of times corresponding to the weight indicated by the subfield. As described above, in the sustain period of the first subfield, the sustain discharge occurs stably even when a sustain discharge pulse for maintaining the Vs voltage is applied during the T1 period. In addition, as the T1 period is smaller, the number of sustain discharge pulses that can be applied in the sustain period of the first subfield increases, thereby increasing the luminance of the plasma display device.

As shown in FIG. 3, in the sustain period of the second subfield having the auxiliary reset period, the second sustain discharge pulse which maintains the Vs voltage for a T2 period longer than the T1 period is applied. Then, sustain discharge occurs during the T2 period longer than the T1 period, thereby compensating for the formation of less wall charges in each electrode than in the main reset period after the auxiliary reset period. The sustain discharge of the second subfield having the auxiliary reset period can be made stable.

On the other hand, the auxiliary reset period will be described. In the reset period of the second subfield, that is, the auxiliary reset period, the voltage of the Y electrode is gradually decreased from the Vs voltage to the Vnf voltage while the Ve voltage is applied to the X electrode. . At this time, when sustain discharge has occurred in the sustain period of the first subfield, since the negative wall charges are formed on the Y electrode and the positive wall charges are formed on the X electrode and the A electrode, the reset period of the first subfield is performed. As with the falling period of, the weak discharge occurs between the Y and X electrodes and between the Y and A electrodes while the voltage of the Y electrode is gradually decreased, The positive wall charges formed are erased to initialize the discharge cells. At this time, since the final voltage Vnf of the Y electrode in the auxiliary reset period is the same as the final voltage Vnf of the Y electrode in the reset period of the first subfield, the wall charge state of the cell after the completion of the auxiliary reset period is set to the first subfield. It becomes substantially the same as the wall charge state after the end of the reset period of the field. The cell in which the address discharge has not occurred in the address period of the first subfield maintains the wall charge state after the end of the reset period of the first subfield. Since the wall voltage formed in the cell after the end of the reset period of the first subfield is formed near the discharge start voltage together with the applied voltage, no discharge occurs when the voltage of the Y electrode decreases to the Vnf voltage. Therefore, since such a discharge does not occur in the auxiliary reset period, the cell maintains the wall charge state set in the reset period of the first subfield. As described above, in the subfield having the auxiliary reset period, reset discharge occurs when sustain discharge occurs in the immediately preceding subfield, and reset discharge does not occur when there is no sustain discharge.

Since the address period and the sustain period of the second subfield are the same as the first subfield, detailed description thereof will be omitted. However, in the sustain period of the second subfield, the second sustain discharge pulse which maintains the Vs voltage for the T2 period is applied to the Y electrode and the X electrode for the number of times corresponding to the weight indicated by the subfield in the opposite phase.

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, in the embodiment of the present invention, in the sustain period of the subfield having the main reset period, the Y electrode and X receive the first sustain discharge pulse that maintains the voltage Vs during the T1 period, which is a period in which sustain discharge may occur. By alternately applying to the electrodes, the number of times that the sustain discharge pulse is applied in the sustain period is increased to increase the brightness. In addition, in the sustain period of the subfield having the auxiliary reset period, the stability of the sustain discharge is ensured by applying the second sustain discharge pulse which maintains the Vs voltage during the T2 period longer than the T1 period.

Claims (6)

A method of driving a plasma display device comprising a plurality of first electrodes and a plurality of second electrodes performing a display operation together with the plurality of first electrodes. Applying a first sustain discharge pulse to the plurality of first electrodes or the plurality of second electrodes in the sustain period of the first subfield having a main reset period for initializing all the discharge cells, and Applying a second sustain discharge pulse to the plurality of first electrodes or the plurality of second electrodes in the sustain period of the second subfield having an auxiliary reset period for initializing the discharge cells displaying the image in the immediately preceding subfield. Including; The first period in which the high level of the second sustain discharge pulse is maintained is longer than the second period in which the high level of the first sustain discharge pulse is maintained. The method of claim 1, And the second period is a minimum period during which sustain discharge can occur. The method of claim 1, The main reset period includes a period in which the voltages of the plurality of second electrodes gradually increase and a period in which the voltages of the plurality of second electrodes gradually fall. The method of claim 1, And the auxiliary reset period includes a period in which voltages of the plurality of second electrodes gradually fall. A plasma display panel including a plurality of first electrodes and a plurality of second electrodes, A driving unit driving the plasma display panel; The driving unit, In the sustain period of the first subfield having a main reset period for gradually increasing and decreasing the voltages of the plurality of first electrodes, a first sustain discharge pulse for maintaining a high level voltage for a first period is generated. Applied to one electrode or the plurality of second electrodes, In a sustain period of a second subfield having an auxiliary reset period for gradually decreasing voltages of the plurality of first electrodes, a second sustain discharge pulse for maintaining a high level voltage for a second period longer than the first period; A plasma display device applied to a plurality of first electrodes or a plurality of second electrodes. The method of claim 5, And the first period is a minimum period during which sustain discharge can occur.

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