KR100658343B1 - Plasma display apparatus and driving method thereof - Google Patents

Abstract

A plasma display device and a driving method thereof are provided to execute smooth initializing during the reset period of the next subfield by keeping a predetermined voltage on an address electrode in driving a plasma display panel by applying negative sustain pulse. A plasma display device includes a plasma display panel(500) having scan and sustain electrodes(Y1~Yn,Z) to which negative sustain pulse is applied in turn during a sustain period, and address electrodes(X1~Xm) selecting a cell; driving units(502,503,504) for driving the plasma display panel by applying signals to the electrodes; and a voltage control unit(501) for keeping a negative bias voltage on the address electrode during the sustain period of plural subfields by controlling the driving units.

Description

Plasma display device and driving method thereof {Plasma Display Apparatus and Driving Method}

1 is a diagram showing the structure of a typical plasma display panel.

FIG. 2 is a diagram illustrating a method of implementing image gradation of a typical plasma display panel. FIG.

3 is a view illustrating a driving waveform according to a driving method of a conventional plasma display panel.

4 is a view illustrating a driving waveform according to a negative sustain driving method of a conventional plasma display panel.

5 schematically illustrates a plasma display device according to the present invention;

6 is a view for explaining a method of driving a plasma display device according to the present invention;

The present invention relates to a plasma display apparatus and a driving method thereof, and more particularly, to a plasma display apparatus and a driving method thereof for improving a driving pulse applied in a sustain period so that stable discharge can occur.

In general, a plasma display panel (hereinafter referred to as a PDP) has a reset pulse for initializing a discharge cell, an address pulse for selecting a cell to be discharged, and a discharge cell for maintaining a discharge cell. Sustain pulses are applied a predetermined number of times according to the gray level values of the respective subfields, and the phosphors emit light by the gas discharge generated. The PDP repeats the above-described reset, addressing, and sustain for each subfield constituting the frame. However, in order to improve the PDP driving characteristics, a wall remaining on each electrode side before the start of each subfield is started. It is necessary to apply an erase pulse to remove the charge.

1 illustrates a structure of a general plasma display panel.

As shown in FIG. 1, a plasma display panel includes a front panel in which a plurality of sustain electrode pairs formed by pairing a scan electrode 102 and a sustain electrode 103 are arranged on a front glass 101 that is a display surface on which an image is displayed. 100 and the rear panel 110 on which the plurality of address electrodes 113 are arranged so as to intersect the plurality of sustain electrode pairs on the rear glass 111 forming the rear surface are coupled in parallel with a predetermined distance therebetween. do.

The front panel 100 is made of a scan electrode 102 and a sustain electrode 103, that is, a transparent electrode (a) formed of a transparent ITO material and a metal material to mutually discharge and maintain light emission of the cells in one discharge cell. The scan electrode 102 and the sustain electrode 103 provided as the bus electrode b are included in pairs. The scan electrode 102 and the sustain electrode 103 are covered by one or more upper dielectric layers 104 that limit the discharge current and insulate the electrode pairs, and to facilitate the discharge conditions on the upper dielectric layer 104 top surface. A protective layer 105 on which magnesium oxide (MgO) is deposited is formed.

The rear panel 110 is arranged such that a plurality of discharge spaces, that is, barrier ribs 112 of a stripe type (or well type) for forming discharge cells are maintained in parallel. In addition, a plurality of address electrodes 113 which perform address discharge to generate vacuum ultraviolet rays are arranged in parallel with the partition wall 112. On the upper side of the rear panel 110, R, G, and B phosphors 114 which emit visible light for image display during address discharge are coated. A lower dielectric layer 115 is formed between the address electrode 113 and the phosphor 114 to protect the address electrode 113.

A method of implementing image gradation in such a plasma display panel is shown in FIG. 2.

2 is a diagram illustrating a method of implementing image grayscale of a general plasma display panel.

As shown in FIG. 2, in the conventional method of expressing a gray level of a plasma display panel, a frame is divided into several subfields having different number of emission times, and each subfield is a reset period (RPD) for initializing all cells again. ) Is divided into an address period APD for selecting a cell to be discharged and a sustain period SPD for implementing gradation according to the number of discharges. For example, when displaying an image with 256 gray levels, a frame period (16.67 ms) corresponding to 1/60 second is divided into eight subfields SF1 to SF8 as shown in FIG. 2, and eight subfields. Each of the SFs SF1 to SF8 is divided into a reset period, an address period, and a sustain period.

The reset period and the address period of each subfield are the same for each subfield. The address discharge for selecting the cell to be discharged is caused by the voltage difference between the address electrode and the transparent electrode which is the scan electrode. The sustain period is increased at a rate of 2 ⁿ ( ^where n = 0, 1, 2, 3, 4, 5, 6, 7) in each subfield. In this way, since the sustain period is different in each subfield, the gray scale of the image is expressed by adjusting the sustain period of each subfield, that is, the number of sustain discharges. The driving waveforms according to the driving method of the plasma display panel are shown in FIG. 3.

3 is a diagram illustrating a driving waveform according to a driving method of a conventional plasma display panel.

As shown in FIG. 3, the plasma display panel is driven by being divided into a reset period for initializing all cells, an address period for selecting a cell to be discharged, and a sustain period for maintaining discharge of the selected cell.

In the reset period, the rising ramp waveform Ramp-up is simultaneously applied to all the scan electrodes Y during the setup period SU. Due to this rising ramp waveform, discharge occurs in the discharge cells of the full screen. By this setup discharge, positive wall charges are accumulated on the address electrode X and the sustain electrode Z, and negative wall charges are accumulated on the scan electrode Y. During the set-down period SD, after the rising ramp waveform is supplied, the ramp ramp starts to fall from the positive voltage lower than the peak voltage of the rising ramp waveform and then falls to the base voltage GND or the specific voltage level of the negative ramp. -down) is applied. As a result, a weak erase discharge is generated in the discharge cells, so that the excessively formed wall charge is partially erased, and the wall charge enough to cause the address discharge to be stably caused by the set down discharge remains uniformly in the discharge cells. .

In the address period, the negative scan pulse Scan is sequentially applied to the scan electrodes Y, and the positive data pulse data is applied to the address electrodes X in synchronization with the scan pulse. An address discharge is generated in the discharge cell to which the data pulse is applied while the voltage difference between the scan pulse and the data pulse and the wall voltage caused by the wall charge generated in the initialization period are added. In the discharge cells selected by the address discharge, wall charges such that a discharge can occur when a sustain voltage is applied are formed. At this time, the positive electrode DC voltage Zdc is supplied to the sustain electrode Z to reduce the voltage difference between the scan electrode Y during the set-down period and the address period so as to prevent erroneous discharge from the scan electrode Y.

In the sustain period, a sustain pulse Su is applied to the scan electrodes Y and the sustain electrodes Z alternately. In the discharge cell selected by the address discharge, the sustain voltage, that is, the display discharge, is generated between the scan electrode Y and the sustain electrode Z every time the sustain pulse is applied as the wall voltage and the sustain pulse in the discharge cell are added.

On the other hand, the plasma display device as described above has a relatively low potential difference as the positive sustain pulse su is alternately applied to the scan electrode Y side and the sustain electrode Z side during the sustain period. Cations are accumulated on the address electrode X side. At this time, the cations, which are heavier than the electrons, exert an ion bombardment on the fluorescent layer (114 in FIG. 1) of the rear panel on which the above-described address electrode X is formed, which shortens the lifespan of the plasma display apparatus. Caused it.

Recently, as shown in FIG. 4, the sustain pulse su is described above to have a negative voltage level, and electrons are formed on the rear panel on which the scan electrode Y and the sustain electrode Z are formed. Negative sustain is driven to accumulate.

4 is a diagram illustrating a driving waveform according to a negative sustain driving method of a conventional plasma display panel.

 As shown in FIG. 4, a negative negative sustain pulse (-sus) is alternately applied to the scan electrode (Y) and the sustain electrode (Z) during the sustain period.

Accordingly, as described above, electrons are accumulated in the rear panel 110 having the fluorescent layer 114 formed by the negative sustain pulse (-sus) described above. Thus, the impact on the fluorescent layer 114 is reduced. On the other hand, in the process of accumulating cations in the front panel 100, an ion bombardment amount is increased in the magnesium oxide (MgO) layer 105 formed on the front panel 100 to improve the secondary electoral generation rate. .

That is, while preventing the loss of the fluorescent layer 114, the secondary electron generation amount is increased to increase the lifetime of the plasma display device and to lower the discharge start voltage.

On the other hand, while the negative sustain pulse is supplied to the scan electrode or the sustain electrode during the sustain period, the ground (GND) level voltage is maintained at the address electrode. As such, when the ground level voltage is maintained at the address electrode, negative wall charges are accumulated on the address electrode relative to the scan electrode and the sustain electrode. This negative charge has difficulty in initializing all the discharge cells in the reset period of the next subfield.

That is, in the reset period of the next subfield, although not shown in the drawing, the reset pulse of the positive ramp waveform having a predetermined voltage is supplied to accumulate negative wall charges on the scan electrodes to initialize the discharge cells. In the previous subfield, when the negative wall charge is maintained on the address electrode, there is a problem in that the voltage of the reset pulse needs to be increased relatively to accumulate the negative wall charge on the scan electrode.

Therefore, it is necessary to increase the setup voltage for initializing the discharge cells in the reset period, and this increase in the setup voltage brings about a problem that may cause an erroneous discharge in the subsequent address period.

Accordingly, an object of the present invention is to provide a plasma display apparatus and a driving method thereof which can improve overall discharge characteristics by improving a bias voltage applied to an address electrode when a negative sustain pulse is applied to a scan electrode or a sustain electrode in a sustain period. .

A plasma display apparatus according to the present invention for achieving the above object is a plasma display panel in which a scan electrode and a sustain electrode and an address electrode for cell selection are alternately applied to the negative sustain pulse alternately applied to each other during the sustain period, the electrodes A control unit for driving the plasma display panel by applying a signal to the control unit, and a voltage adjusting unit configured to control the driving unit to maintain a negative bias voltage at the address electrode during the sustain period of the plurality of subfields. Include.

The negative bias voltage is lower than the voltage of the negative sustain pulse.

In the method of driving a plasma display device according to the present invention, discharge is sustained by alternately applying a negative sustain pulse to a scan electrode and a sustain electrode in a sustain period, and the sustain period is applied to an address electrode intersecting the scan electrode and the sustain electrode. While maintaining the negative bias voltage.

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

5 is a view for explaining a plasma display device according to the present invention.

As shown in FIG. 5, the plasma display device according to the present invention is provided with the address electrodes X1 to Xm, the scan electrodes Y1 to Yn, and the sustain electrode Z in the above-described reset period, address period and sustain period. Supplying data to the plasma display panel 500 expressing an image composed of a frame by applying a driving pulse and combining at least one subfield, and the address electrodes X1 to Xm formed on the plasma display panel 500. The data driver 502, the scan driver 503 for driving the scan electrodes Y1 to Yn, the sustain driver 504 for driving the sustain electrodes Z which are common electrodes, and the sustain period. Generation of a driving voltage for supplying a driving voltage necessary for the voltage adjusting unit 501 for adjusting the voltage applied to the address electrode, and for each of the driving units 502, 503, and 504. It comprises a 505. The

The data driver 502 is subjected to inverse gamma correction and error diffusion by an inverse gamma correction circuit, an error diffusion circuit, and the like not shown, and then data mapped to each subfield is supplied by the subfield mapping circuit. The data driver 502 samples and latches data in response to a data timing control signal CTRX from a timing controller (not shown), and then supplies the data to the address electrodes X1 to Xm. Done. In addition, an erase pulse is supplied to the address electrodes X1 to Xm during the erase period.

The scan driver 503 supplies the reset pulses to the scan electrodes Y1 to Yn during the reset period, the scan pulses to the scan electrodes Y1 to Yn during the address period, and scans the negative sustain pulses during the sustain period. The electrodes are supplied to the electrodes Y1 to Yn, and an erase pulse is supplied to the scan electrodes Y1 to Yn during the erase period.

The sustain driver 504 supplies a bias voltage having a predetermined magnitude to the sustain electrodes Z during the address period, and alternately operates with the scan driver 503 described above during the sustain period to generate a negative sustain pulse (-sus). To the field (Z).

The voltage adjusting unit 501 adjusts the voltage of the pulse applied to each electrode during the reset period, the address period, and the sustain period. The voltage adjusting unit 501 may be configured as a voltage source of each driving pulse in the scan driver or the sustain driver.

The data control signal CTRX described above includes a sampling clock for latching data, a latch control signal, a switch control signal for controlling the on / off time of the energy recovery circuit and the driving switch element. The scan control signal CTRY includes a switch control signal for controlling on / off time of an energy recovery circuit (not shown) and a driving switch element (not shown) in the scan driver 503, and a sustain control signal CTRZ. Includes a switch control signal for controlling the on / off time of the energy recovery circuit and the drive switch element in the sustain driver 504.

The driving voltage generator 505 generates a setup voltage Vsetup, a scan common voltage Vscan-com, a scan voltage -Vy, a sustain voltage Vs, a data voltage Vd, and the like. These driving voltages may vary depending on the composition of the discharge gas or the structure of the discharge cell.

6 is a waveform diagram illustrating a method of driving a plasma display device according to the present invention.

As shown in FIG. 6, the plasma display apparatus is driven by being divided into a reset period for initializing all screens of the plasma display panel, an address period for selecting cells, and a sustain period for maintaining discharge of the selected cells. do.

First, during the setup period of the reset section, the positive ramp pulse rising up to the setup voltage Vset-up is simultaneously applied to all the scan electrodes Y, and the negative pulse is applied to the sustain electrode Z. At this time, the voltage of the negative pulse is the same voltage level as that of the negative sustain pulse supplied in the subsequent sustain period. This causes a weak discharge in the discharge cells of the entire screen due to the potential difference between the scan electrode and the sustain electrode to accumulate wall charges.

Thereafter, in the set-down period, the wall charges accumulated in the discharge cells are erased in the set-up period so that the wall charges of all the discharge cells can be uniformed. A negative ramp pulse descending until is applied, and at the same time, the ground electrode is maintained at the sustain electrode.

In the address period, the negative scan pulse (-Vsp) is applied to the scan electrode (Y) while maintaining the scan bias voltage (Vscan) lower than the ground voltage level and higher than the voltage (-Vs) of the negative sustain pulse applied in the sustain period. Supply. At this time, the ground level supplied to the sustain electrode during the set down period is maintained. In addition, the address electrode X supplies a data pulse in synchronization with the negative scan pulse -Vsp applied to the scan electrode. As a result, the voltage difference between the negative scan pulse and the data pulse and the wall voltage generated during the reset period are added, and an address discharge is generated in the cell to which the data pulse is applied.

In the sustain period, a negative sustain pulse sus is alternately applied to the scan electrode and the sustain electrode. Such a negative sustain pulse causes a sustain discharge, that is, a display discharge, between the scan electrode and the sustain electrode every time a negative sustain pulse is applied in addition to the wall voltage in the cell selected in the address period. At this time, the negative bias voltage (-Vd) is maintained at the address electrode. The absolute voltage of this negative bias is smaller than the absolute voltage of the negative sustain pulses applied to the scan electrode and the sustain electrode. Accordingly, positive charges in the space charges in the discharge space during the sustain period are accumulated on the address electrode.

When positive charges accumulate on the address electrode in this manner, the wall charges in the entire discharge cells can be easily uniformed in the reset period of the next subfield. This is because a negative wall pulse is applied to the scan electrodes in the reset period of the next subfield to accumulate negative wall charges, because it is more advantageous than when the address electrodes are maintained at the ground level during the conventional sustain period.

Accordingly, it is possible to prevent the rise of the reset voltage for initializing the discharge cells during the next reset period.

As such, the technical configuration of the present invention described above can be understood by those skilled in the art that the present invention can be implemented in other specific forms without changing the technical spirit or essential features of the present invention.

Therefore, the exemplary embodiments described above are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the appended claims rather than the foregoing detailed description, and the meaning and scope of the claims are as follows. And all changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

In the present invention as described above, when the plasma display panel is driven by applying a negative sustain pulse, the address electrode maintains a predetermined voltage, so that the initialization is performed well in the reset period of the next subfield. There is an effect that the discharge characteristics are improved.

Claims (3)

A plasma display panel including a scan electrode and a sustain electrode to which negative sustain pulses are alternately applied in the sustain period, and an address electrode for cell selection; Respective driving units for driving the plasma display panel by applying a signal to the electrodes; And The voltage adjusting unit controls the driving unit to maintain the negative bias voltage at the address electrode during the sustain period of the plurality of subfields. Plasma display device comprising a. The method of claim 1, The negative bias voltage is lower than the voltage of the negative sustain pulse. In the driving method of the plasma display apparatus which sustains the discharge by applying a negative sustain pulse alternately to the scan electrode and the sustain electrode in the sustain period, And maintaining a negative bias voltage at an address electrode crossing the scan electrode and the sustain electrode during the sustain period.

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