KR100450200B1 - Method for driving plasma display panel - Google Patents

Abstract

In driving the AC plasma display panel, initializing discharge is selectively performed on a cell that has not been discharged in the immediately preceding subfield, and initialization is selectively performed, thereby realizing the darkest part very darkly. One or more subs include an initialization section for initializing the state of each cell, an address section for selecting and writing a cell to be turned on and a cell to be turned off, and a sustain section for discharging a cell designated to be turned on in the address section. A method of driving an AC plasma display panel in which gray scales are displayed by forming one field period with fields, the initializing period is characterized in that the initializing discharge is performed only for the cells discharged in the sustaining period of the immediately preceding subfield.

Description

Plasma display panel driving method {Method for driving plasma display panel}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel (PDP) driving method, and more particularly, to an AC plasma display panel used as a monitor or television receiver of a computer. In one aspect, the present invention relates to a plasma display panel driving method capable of realizing high contrast.

Plasma display panel is a display that displays an image by using discharge phenomenon. In general, plasma display panel can be divided into direct current type and alternating current type according to the type of driving voltage. In the case of direct current type, the structure is complicated and the efficiency is low. Due to the disadvantages, the development of the AC plasma display panel has been made a lot.

As shown in FIG. 1, a general AC display panel is formed of a multi-layered plate, and has a thinner, lighter, and wider space compared to a conventional cathode ray tube (CRT). Able to know.

Referring to the main configuration of the AC display panel with reference to Figure 1, the scan electrode 4 and the sustain electrode (1) between the first glass substrate 1 on the top surface and the second glass substrate 6 on the bottom surface where the discharge cells are located ( 5), and the dielectric layer 2, the protective film 3, and the insulator layer 7 are sequentially placed.

The scan electrode 4 and the sustain electrode 5 between the first glass substrate 1, the dielectric layer 2, and the protective film 3 are paired and arranged in parallel in the longitudinal direction, and the second glass substrate ( 6, an address electrode 8 covered with the insulator layer 7 is provided in the transverse direction, and the partition 9 is formed on the insulator layer 7 in parallel.

Phosphors 10 are formed on the surface of the insulator layer 7 and on both side surfaces of the partition wall 9, and the scan electrode 4 and the sustain electrode 5 are perpendicular to the address electrode 8. And discharge cells 12 are formed at the intersections of the discharge spaces.

Therefore, the discharge cells in the form of a matrix are formed by the number of the scan electrodes 4, the sustain electrodes 5, and the address electrodes 8.

In order to improve the image quality of the plasma display panel configured as described above, it is very important to improve the contrast among various quality-related items.

Contrast is expressed as the ratio of the brightness of the brightest peak white to the brightness in the absence of the darkest discharge in the image displayed on the panel. The peak white consists mainly of the light generated by the sustain discharge, the darkest The part consists of light generated by the initialization discharge.

Therefore, in order to improve the contrast, the brighter part is made brighter or the darker part is made darker, and the lower the background luminance when there is no discharge, the contrast is improved.

However, one field of the signal for driving the AC plasma display panel is composed of 8 to 12 subfields, and each subfield is composed of four sections, each of which is reset. ) Section, address section, sustain section, and erase section.

The address section is a section for applying actual data, and selects a cell that is turned on and a cell that is not turned on in the panel to accumulate wall charges in a cell turned on, and the initialization section is the address. It is a section that initializes the state of each cell in order to perform the operation smoothly before applying data in the section.

The sustain period is a period in which a discharge for actually displaying an image is displayed on the cells addressed by the operation of the address period, and the erasing period reduces the wall charge of the cell to terminate the sustain discharge operation.

However, in the prior art, discharge is performed in each of the subfields regardless of the presence or absence of discharge in the sustain period, which makes it difficult to reduce the background luminance to a predetermined value or less.

In order to solve these problems, a technique for improving contrast by reducing the amount of light caused by the light emission has been proposed. For example, US Patent No. 5,745,086 (Plasma panel exhibiting enhanced contrast, Applicant: Plasmaco Inc.). , Filed Date: Nov. 29, 1995), and Korean Patent Publication No. 2000-53573 (Invention: Method for Driving AC Plasma Display Panel, Applicant: Matsushita Denki Sangyo Co., Ltd., Filed Date: Jan. 21, 2000) Is an example.

The above-mentioned U.S. Patent No. 5,745,086 and Korean Patent Publication No. 2000-53573 propose a driving method that can selectively perform initialization discharge to improve contrast.

However, according to the above patents, a high voltage is applied to scan electrode Y (or sustain electrode X) to accumulate electrons on scan electrode Y (or sustain electrode X), and sustain electrode X (Or scan electrode (Y)) or the address electrode has an initialization waveform formed by stacking ions, so that discharge between sustain electrode (X) and scan electrode (Y) and address electrode (A) and scan electrode (Y) Initialization was performed while generating an interdischarge.

Therefore, according to the prior art as described above takes a considerable time in the initialization time, there is a disadvantage that the maximum voltage is set too high, such as 400 volts (volts) or more when the lamp rises.

Accordingly, an object of the present invention is to solve the disadvantages of the prior art as described above, and in driving the AC plasma display panel, it is possible to realize a high contrast while reducing the initialization time and lowering the voltage when the lamp rises. The present invention provides a method for driving a plasma display panel.

1 is a partial perspective view of an AC plasma display panel;

2 is a block diagram to which a driving apparatus of a plasma display panel according to an exemplary embodiment of the present invention is applied;

3 is a driving waveform diagram applying a plasma display panel driving method according to an embodiment of the present invention;

4 is a view showing a wall charge structure of a discharge cell with addressing conditions.

The configuration of the present invention for achieving the above object, an initialization period for initializing the state of each cell, an address period for selecting and writing a cell to be turned on and a cell to be turned off and a cell designated to be turned on in the address period A method of driving an AC plasma display panel in which one field period is formed by displaying one gray period by using one or more subfields including a sustain period for discharging, in the initialization period, a) a first voltage is applied to a scan electrode and a sustain electrode. Applying; b) after step a), gradually reducing the voltage of the scan electrode and sustain electrode to a negative second voltage; c) after step b), the voltage of the scan electrode and sustain electrode is reduced to the second voltage. And a sustain voltage, alternately applying a voltage pulse for sustain discharge to the scan electrode and the sustain electrode, and at least for the first sustain voltage pulse to the scan electrode or sustain electrode. The voltage of the address electrode is maintained at a third voltage.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

As shown in Figure 2, the configuration of the plasma display panel driving apparatus according to an embodiment of the present invention,

A frame memory 100 for storing digital data to be displayed,

A frame generator 200 for dividing and outputting digital data stored in the frame memory 100 as necessary;

The initialization signal, the address signal, the sustain signal, and the erase signal for driving the panel 700 are generated by using the signal output from the frame generator 200, synthesized into one signal, and maintained with the scan electrode Y driver 600. A scanning circuit 400 output to the electrode X driver 500,

The timing controller 300 generates and outputs a timing signal necessary for the operation of the frame generator 200 and the scanning circuit 400.

The scanning circuit 400 may include an initialization pulse generator 420 for generating a signal for initializing a state of each cell of the panel, and a signal for selecting and addressing cells that are turned on and cells that are not turned on from among the cells of the panel. An address pulse generator 430, a sustain pulse generator 440 for generating a signal for discharging a cell addressed by the address pulse generator 430, and a signal output from the sustain pulse generator 440 to the electrode. The signals output from the erase pulse generator 410, the initialization pulse generator 420, the address pulse generator 430, and the sustain pulse generator 440, which generate a signal for erasing the accumulated wall charges, are synthesized. It consists of a synthesis circuit 450 to supply each star.

Operation of the embodiment of the present invention made as described above is as follows.

As shown in FIG. 2, the frame memory 100 stores and outputs an input digital image signal, and the frame generator 200 divides and scans digital data stored in the frame memory 100 as necessary. Output to circuit 400.

That is, the frame generator 200 divides one frame of the digital image signal stored in the frame memory 100 into a plurality of subfields according to the gradation level, and divides the data of each subfield into the scanning circuit 400. Output

The scanning circuit 400 receives a signal for each subfield output from the frame generator 200 and drives a scan electrode Y drive 600 and a sustain electrode drive 500 of the panel 700. Generates and outputs an initialization pulse, an address pulse, a sustain pulse, and an erase pulse, and synthesizes and outputs respective signals.

That is, the initialization pulse generator 420 generates a signal for initializing the state of each cell of the panel, and the address pulse generator 430 generates a signal for selecting and addressing cells that are turned on and cells that are not turned on among the cells of the panel. do.

In addition, the sustain pulse generator 440 generates a signal for discharging the cell addressed by the address pulse generator 430, and the erase pulse generator 410 generates the signal by the signal output from the sustain pulse generator 440. Generates a signal to erase the wall charges accumulated in the wall.

In addition, the synthesizing circuit 450 synthesizes signals output from the initialization pulse generator 420, the address pulse generator 430, and the sustain pulse generator 440, and supplies the synthesized signals for each electrode.

Hereinafter, an operation of the scanning circuit will be described in detail with reference to FIG. 3.

First, the initialization pulse generator 420 generates an initialization signal applied to each electrode, without generating a discharge between the scan electrode (Y) and the sustain electrode (X), the scan electrode (Y) and the address electrode (A) Alternatively, a discharge is generated between the sustain electrode X and the address electrode A. FIG.

That is, as shown in FIG. 3, the initializing discharge is applied by applying a pulse signal having a constant first voltage Vp to the scan electrode Y and the sustain electrode X at the beginning of the initialization period, but not to the address electrode. Let's do it.

Then, the ramp signal is applied to fall to the second voltage Vsc with a constant slope, and when the ramp signal reaches the second voltage Vsc, a negative pulse signal of that value is generated for a predetermined time.

The reason for lowering the scan electrode Y potential and the sustain electrode X potential in the form of a lamp as described above is between the scan electrode Y and the address electrode A, or between the sustain electrode X and the address electrode A. The purpose of preventing wall charges from being erased by self-erase discharge is to prevent the wall charges by lowering the potential of the sustain electrode X to the second voltage Vsc. This is to prevent the discharge between the sustain electrode X and the address electrode A while the potential rises to the third voltage Va.

The ramp-down of the potential of the scan electrode Y to the second voltage Vsc is a basic operation for performing an address operation. Thus, the scan electrode Y and the sustain electrode X are the same. Accumulation of polarity charges prevents discharge from occurring in unaddressed cells.

After the initialization is completed by the initialization pulse generator 420 as described above, the address pulse generator 430 generates an address signal corresponding to one subfield of the image signal. In this section, the scan electrode Y is caused by the address discharge. The polarity of the wall charge of is completely reversed, and the potential of the sustaining electrode X should not be involved in the discharge, thereby increasing the potential by the fourth voltage Ve.

This part is different from the conventional driving method, and according to the conventional driving method, after the wall charge is set up so that a firing voltage is applied between the scan electrode Y and the sustain electrode X, The addressing discharge is terminated by triggering the discharge by the address discharge and inverting the polarities of the wall charges accumulated on the scan electrode Y and the sustain electrode X.

However, in the present invention, addressing is performed by completely changing the polarity of the scan electrode Y wall charge while maintaining the wall charge of the sustain electrode X as it is, and in order to completely change the polarity of the wall charge, externally between the electrodes. The voltage to be applied must be larger than the minimum discharge holding voltage (Vs, min) between the two electrodes to ensure inversion.

Therefore, the driving method of the present invention is designed such that the sum of the second voltage Vsc and the third voltage Va, which is an applied voltage for discharging, is greater than the minimum discharge holding voltage Vs, min. As shown in FIG. 4, the wall charges have a large amount of positive charges in the address electrode A and a large amount of negative charges in the scan electrode Y.

However, since the wall charges are completely reversed by discharging by addressing between the address electrode A and the scan electrode Y as described above, when a positive voltage is applied to the scan electrode Y, the address electrode Discharge may occur again between (A) and the scan electrode (Y) to prevent the discharge between the scan electrode (Y) and the sustain electrode (X).

Accordingly, in the sustaining period, the potential of the address electrode A is varied to the third voltage Va to reduce the discharge between the address electrode A and the scan electrode Y, and the scan electrode Y and the sustain electrode X are reduced. Allow discharge of the liver to occur.

In FIG. 3, the potential of the address electrode A is maintained at the third voltage Va in the sustain period, but the potential may be lowered to 0 volts after the first sustain pulse.

When the sustain period ends as described above, finally, as the erasing period control, the discharge is completed by applying the rising ramp voltage to the sustain electrode X to erase the wall charges, and the cells in which the discharge does not occur are sustained. Negative charges are accumulated on both the and scan electrodes Y, so that no discharge occurs in the erase period.

When the erase period is completed as described above, initializing discharge is performed again to set up wall charges. Since cells that have not been discharged previously do not operate because of the wall charges accumulated by the previous initialization discharges, selective initialization is performed. Therefore, by preventing unnecessary discharge in the darkest part, the contrast expressed by the ratio of peak white and no discharge can be improved.

In addition, in FIG. 3, a charge of the same polarity begins to be accumulated on the scan electrode Y and the sustain electrode X at the beginning of the initialization period. When this is applied, even if the polarity of the waveform is reversed, high contrast, which is an object of the present invention, can be realized. Can be.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Therefore, in the present invention operating as described above, in driving the AC plasma display panel, the darkest part is performed by selectively performing initialization by not initializing discharge to a cell that has not been discharged in the immediately preceding subfield. There is an effect that the contrast can be improved by darkening the.

Accordingly, the present invention can reduce the time required for the initialization discharge, and has the effect of realizing high contrast while lowering the voltage at the time of ramp up.

Claims (6)

One field including one or more subfields including an initialization section for initializing the state of each cell, an address section for selecting and writing a cell to be turned on and a cell to be turned off, and a sustain section for discharging a cell designated to be turned on in the address section. In the driving method of an AC plasma display panel which constitutes a period and displays gray scales, In the initialization section, a) applying a first voltage to the scan electrode and the sustain electrode; b) after step a), gradually reducing the voltages of the scan electrode and sustain electrode to a negative second voltage; c) after step b), maintaining the voltage of the scan electrode and sustain electrode at the second voltage; In the maintenance section, Alternately applying a voltage pulse for sustain discharge to the scan electrode and the sustain electrode, and maintaining the voltage of the address electrode at a third voltage for at least a period in which a first sustain voltage pulse is applied to the scan electrode or the sustain electrode. Plasma Display Panel Driving Method. The method of claim 1, B), Applying a ramp waveform that reduces to the second voltage with a constant slope Plasma Display Panel Driving Method. The method of claim 1, In the address section, Applying the third voltage pulse to an address electrode of a cell to be turned on, and applying the second voltage pulse to a scan electrode, Maintaining the voltage of the sustain electrode to the fourth voltage; Plasma Display Panel Driving Method. delete The method according to claim 1 or 3, The sum of the second voltage and the third voltage is greater than the voltage for the sustain discharge. Plasma Display Panel Driving Method. The method according to claim 1 or 3, The subfield further includes an erase period after the sustain period. In the erasing interval, A ramp waveform rising from the fourth voltage to the fifth voltage is applied to the sustain electrode, and the voltage of the address electrode is maintained at the third voltage. Plasma Display Panel Driving Method.