KR20000001748A - Method and device for driving a plasma display panel - Google Patents

Abstract

PURPOSE: A plasma display panel driving device and a method thereof are provided to easily adjusting white balance and average picture level by controlling the number of sustain discharge operations. CONSTITUTION: The plasma display panel driving method comprises the steps of: detecting a brightness of an image signal on an input line; and adjusting the number of sustain pulses by controlling a point of time of generating an erase pulse in accordance with the detected brightness. By the method, white balance and average picture level are easily adjusted by controlling a time of point of generating an erase pulse according to the brightness and the number of the sustain pulses.

Description

Apparatus of Driving Plasma Display Panel and Method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel (PDP), which is one of flat panel display apparatuses. In particular, the present invention relates to a PDP drive that can easily adjust white balance and average image level by controlling the number of sustain discharges. An apparatus and method are provided.

In recent years, PDPs that display images using gas discharge phenomenon are expected to be a flat panel display device that can replace bulky cathode ray tubes (CRTs) due to their thinness and size. The PDP obtains a discharge through voltage control applied between vertical and horizontal electrodes of a cell constituting a pixel, and displays an image by controlling the amount of light discharged by controlling the length of the discharge time. The full screen includes a write pulse for inputting a digital image signal to the vertical and horizontal electrodes of the cell, a scan pulse for scanning, a sustain pulse for sustaining the discharge, and a discharge of the discharged cell. An erase pulse for stopping the signal is applied and driven in a matrix form. In this case, the step brightness required for image display, that is, gray scale, is a time for discharging individual cells within a given time (for example, 16 ms) to display an image of one frame corresponding to one screen. This can be achieved by adjusting the length of. In general, in the case of a flat panel display device for displaying an image, 256 gray levels are required, and an image digital signal for displaying an image of 256 gray levels requires an 8 bit signal for each of the color signals R, G, and B. Do. In addition, in order to obtain the high luminance required by the display device, the number of sustain discharges per unit time should be as high as possible.

The PDP is classified into a direct current (DC) type driven by a direct current voltage and an alternating current (AC) type driven by an AC voltage according to the type of driving voltage. Hereinafter, only a driving method of the AC type PDP will be described.

FIG. 1 schematically shows a configuration of a conventional PDP driving apparatus. The PDP driving apparatus shown in FIG. 1 is a Y sustain driving circuit for driving Y sustain electrodes Y1 to Ym disposed in the PDP 10. As shown in FIG. 14, the Z sustain drive circuit 14 for driving the Z sustain electrodes Z1 to Zm of the PDP 10, and the address electrodes X1 to Xn of the PDP 10 to the odd address electrode. First and second address driving circuits 18 and 20 for driving the first and second address electrodes X2, X3, ..., Xn-1 and the even-numbered address electrodes X2, X4, ..., Xn separately.

In the PDP driving apparatus shown in FIG. 1, the PDP 10 has Y and Z sustain electrodes Y1 to Ym and Z1 to Zm alternately arranged in the horizontal direction, and address electrodes X1 to Xn arranged in the vertical direction. ). A cell 12 corresponding to one pixel is provided at each intersection of the Y and Z sustain electrodes Y1 to Ym and Z1 to Zm and the address electrodes X1 to Xn, so that the PDP 10 has n × m cells. It will contain the cell. Here, the Y sustain electrodes Y1 to Ym are mainly used to scan a screen and to maintain a discharge, and the Z sustain electrodes Z1 to Zm are mainly used to maintain a discharge, and the address electrodes X1. Xn) is mainly used for data input. To this end, the Y sustain driving circuit 14 maintains a sustain pulse for maintaining the discharge of the cell at each of the Y sustain electrodes Y1, Y2, ..., Ym, and an erase pulse and an address for stopping the discharge of the discharged cell. Scan pulses and the like synchronized with the video data signals applied to the electrodes X1 to Xn are supplied. Similarly, the Z sustain drive circuit 16 supplies a sustain pulse or the like to the respective Y sustain electrodes Z1, Z2, ..., Zm. The first address driver circuit 18 supplies data pulses synchronized with the scan pulses to the respective odd-numbered address electrodes X1, X3, ..., Xn-1, and the second address driver circuit 20 also Data pulses are supplied to each even-numbered address electrode X2, X4, ..., Xn.

The PDP of this structure expresses the gray level of an image by adjusting the number of sustain discharges per unit time. The PDP driving method for expressing the gray level of an image is classified into a sub-field method and a sub-frame method according to the driving method.

For example, in the case of expressing 256 gray levels, the susfield driving method time-divisions one frame into eight subfields, and each subfield writes data while scanning the full screen in a sequential manner with a reset period for initializing the full screen. It is time-divided into an address period and a sustain period for maintaining the light emission state of cells in which data is written. Here, the reset period and the address period of each subfield are the same, while each sustain period is 2 ⁿ Each subfield implements a gradation proportional to its sustain period and expresses 256 gradations of one frame by combining the gradations implemented in each subfield. Done. However, the above-described subfield driving method requires scanning the entire screen for each address period of each subfield, and therefore, there is a disadvantage in that misdischarge and uneven discharge occur in the next sustain period due to the time required for this address period.

On the other hand, the subframe driving method is to compensate for the shortcomings of the above-described subfield method, and the addressing period of the full screen is partially distributed at every cycle of the sustain pulse, so that the sustaining process is continued without interruption over one frame. This is how you do it. In detail, in the case of expressing 256 gray levels, in the subframe method, eight time intervals (T, 1 / 2T, 1 / 4T, 1 / 8T, 1 / 16T, 1 / 32T, 1 / 64T, 1 / 128T) and discharge weights are assigned to each time interval similarly to the above-described subfield method. Accordingly, there are eight screen blocks having different brightness levels, that is, different subfield states, on the full screen at any point in time. In addition, the eight horizontal lines selected in the division boundary of the eight blocks, that is, one sustain pulse period, are repeatedly moved one horizontal line down for each sustain pulse period, thereby reducing the total number of horizontal lines (for example, 512). When the corresponding sustain period ends, 256 gray levels of one frame are expressed.

Referring to FIG. 2, when the PDP of FIG. 1 is driven in a sub-frame selective erasure method, the first Y and Z from each of the Y and Z sustain drivers 14 and 16 shown in FIG. Voltage waveforms supplied to the Z sustain electrodes Y1 and Z1 are shown in (A) and (B).

In general, when the PDP is driven in a subframe manner, the sustain pulses s having opposite shapes to each other are basically supplied to the Y and Z sustain electrodes Y1 and Z1 as shown in FIG. 2. When data should be written to the Y sustain electrode Y1 at any point in time, an erase pulse e is first applied as shown in (A) to generate an erase discharge, thereby maintaining the previous gray scale. Stop the sustain discharge. Subsequently, the writing pulse w added to the sustain basic pulse s is applied to the Y sustain electrode Y1 and the Z sustain electrode Z1 to cause a lighting discharge, thereby causing the cells provided in the first horizontal line to be turned on. It becomes a state. Then, a scan pulse synchronized with a data pulse applied to the address electrode, that is, an erase pulse (not shown) is applied to the Y sustain electrode Y1 so that only cells without display data are turned off and turned on. The cells maintaining Δ are sustained by the sustain pulse s applied to the Y and Z sustain electrodes Y1 and Z1 to implement a desired gray scale.

As described above, in the conventional PDP driving method, an erasing discharge is generated before erasing a writing discharge, the previous gray level is erased, and the next gray level is expressed. In this case, there is a problem that accurate white balance reproduction is impossible. In addition, since the number of sustain discharges within a predetermined unit time is determined according to the bit weighting value, when the average picture level (APL) is small, there is a problem that the contrast ratio is lowered and the image quality is lowered. In addition, when the difference between the average image level (APL) is large, there is a problem that the consumption of power consumption is large.

Accordingly, it is an object of the present invention to provide a PDP driving apparatus and method which can easily adjust white balance and image average level by adjusting the number of sustain pulses.

Another object of the present invention is to provide a PDP driving apparatus and method capable of improving image quality by adjusting the number of sustain pulses to improve contrast ratio.

1 is a view schematically showing a driving apparatus of a conventional PDP.

2 is a voltage waveform diagram illustrating a conventional PDP driving method of a subframe selective erasure method.

3 is a block diagram showing a PDP driving apparatus according to the present invention.

4 is a voltage waveform diagram for explaining a PDP driving method according to the present invention.

<Brief description of symbols for the main parts of the drawings>

10: PDP 12: Cell

14: Y sustain drive circuit 16: Z sustain drive circuit

18: first address driver circuit 20: second address driver circuit

22: luminance detector 24: scan circuit

26: sustain circuit 28: drive IC

In order to achieve the above objects, the PDP driving apparatus according to the present invention includes a plasma display panel having cells provided at intersections of first and second sustain electrodes forming each scan line and address electrodes forming a column, Sustain pulse generating means for generating sustain pulses, luminance detecting means for generating a control signal according to the brightness by detecting the brightness from the image signal of the input line, erasing pulses according to the control signal at the corresponding point, and for generating the writing pulse. And an integrated circuit means for synthesizing the sustain pulse and the writing and erasing pulses and supplying the first and second sustain electrodes.

The PDP driving method according to the present invention is characterized in that the number of sustain pulses is adjusted by detecting a luminance from an image signal of an input line and adjusting an occurrence time of erase pulses according to the detected luminance.

Other objects and advantages of the present invention in addition to the above object will become apparent from the description of the preferred embodiment of the present invention with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 3 and 4.

FIG. 3 schematically illustrates a configuration of a PDP driving apparatus for explaining a PDP driving method according to an embodiment of the present invention, wherein the PDP driving apparatus shown in FIG. 3 is included in the sustain driving circuit shown in FIG. 1. A luminance detection unit 22 for detecting luminance from an image signal through the input line 21, a sustain circuit 26 for generating basic sustain pulses, and an erase pulse in accordance with control signals from the writing pulse and the luminance detection unit 22; A scan circuit 24 for generating a?, A drive IC unit 28 commonly connected to the sustain circuit 26 and the scan circuit 24, and a PDP 10 driven for each line by the drive IC 28? do.

In the PDP driving apparatus of FIG. 3, the luminance detector 22 detects a level of an image signal (that is, a luminance signal) input through the input line 21 and according to the image signal level when the image signal level is relatively small or large. The control signal is output to the scan circuit 24. As shown in FIG. 4, the sustain circuit 26 generates sustain pulses, which are basically supplied to the Y and Z sustain electrodes, at a predetermined period and supplies them to the driving IC unit 28. The scan circuit 24 generates the writing and erasing pulses at the time when the writing and erasing discharge should occur. Here, the scan circuit 24 generates an erase pulse by adjusting the timing of generating the erase pulse in accordance with a control signal from the luminance detector 22. In other words, the scan circuit 24 generates the erase pulse by adjusting the number of sustain pulses according to the control signal. The driving IC unit 28 combines the writing and erasing pulses from the scan circuit 24 with the sustain pulses from the sustain circuit 26 and supplies them to each of the sustain electrodes Y and Z arranged in the PDP 20, and supplies a line. Run it too.

4 illustrates a voltage waveform supplied to a first Y sustain electrode Y1 and a first Z sustain electrode Z1 forming a first scan line of the PDP 10 according to the present invention. have.

First, the sustain pulse s is supplied to the first Y and Z sustain electrodes Y1 and Z1 in a form opposite to each other at regular intervals. If the average image level detected by the luminance detector 22 is relatively low or high before applying the erase pulse e for turning off cells without data in the address period in any sustain period, it is applied from the luminance detector 22. The generation time of the erasing pulse e is adjusted by the control signal. For example, when the average image level is low, the erase pulse e is supplied to the first Y sustain electrode Y1 by an arbitrary sustain pulse period as shown in FIG. 4, and when the average image level is high, any sustain pulse is high. Supply delayed by the cycle.

As a result, when the PDP according to the present invention is driven by the susframe selective erasure method, the luminance is detected from the input image signal, and when the luminance is low or high, the timing of generation of the erase pulse is adjusted.

As described above, according to the PDP driving apparatus and method according to the present invention, when the PDP is driven in a sub-frame method, when the PDP according to the present invention is driven in a sus frame selection erasing method, the luminance is detected from the input video signal. When is low or high, it controls the point of occurrence of erasing pulse. As a result, the white balance and the average image level can be easily adjusted according to the luminance, and the contrast ratio can be improved.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (6)

A plasma display panel including cells provided at intersections of first and second sustain electrodes constituting each scan line and address electrodes constituting columns; Sustain pulse generating means for generating a sustain pulse of a constant period, Luminance detection means for detecting luminance from an image signal of an input line and generating a control signal according to the luminance; A scan pulse generating means for generating an erase pulse and a writing pulse according to the control signal at a corresponding time point; And an integrated circuit means for synthesizing the sustain pulses and the writing and erasing pulses and supplying the sustain pulses to the first and second sustain electrodes, respectively. The method of claim 1, And an address driving means for driving the address electrodes. A method of driving a plasma display panel including cells provided at intersections of first and second sustain electrodes forming each scan line and address electrodes forming a column, the method comprising: And detecting the luminance from the image signal of the input line and adjusting the number of sustain pulses according to the detected luminance to adjust the number of sustain pulses. The method of claim 3, wherein And the erasing pulse causes an erase discharge to occur only in a cell having no data at address. The method of claim 3, wherein And when the detected luminance level is low, relatively shortens the generation time point of the erase pulse. The method of claim 3, wherein And when the detected luminance level is high, relatively delaying the generation point of the erase pulse.