KR20040003774A - Driving method of ac plasma display panel using address pulse during sustain period - Google Patents

Abstract

PURPOSE: A method for driving a plasma display panel to apply a pulse to an address electrode during a sustain discharge period is provided to increase the brightness of the plasma display panel and to reduce the driving voltage thereof during the sustain discharge period. CONSTITUTION: A method for driving a plasma display panel to apply a pulse to an address electrode during a sustain discharge period includes the steps of: applying a pulse having a previously determined frequency and a duty ratio to the address electrode during the sustain discharge period. The plasma display panel includes at least one discharge cells provided with a pair of sustain electrode and an address electrode. And, the method includes a plurality of fields, each of which includes a plurality of sub-fields, each of which includes an address period and a sustain discharge period.

Description

A method of driving a plasma display panel that applies a pulse to an address electrode during a sustain discharge period {DRIVING METHOD OF AC PLASMA DISPLAY PANEL USING ADDRESS PULSE DURING SUSTAIN PERIOD}

The present invention relates to a method of driving a plasma display panel (PDP) for applying a pulse to an address electrode during a sustain discharge period, and more particularly, to an AC plasma display panel using an ADS (Address Display Separate) method. In driving, unlike the prior art in which the address electrode is kept at a constant voltage during the sustain discharge period, a pulse voltage having a predetermined frequency and duty ratio is applied to the address electrode to lower the discharge start voltage, improve the brightness, and also improve the brightness. A driving method for increasing efficiency.

1 shows an example of a general AC type surface discharge plasma display panel. The panel is an AC plasma display panel (hereinafter referred to as "AC PDP") currently commercially available and has a three-electrode surface discharge type structure. In the three-electrode surface discharge type PDP, a pair of sustain electrodes (sustain electrodes or display electrodes) (X, Y) are arranged on the inner surface of the glass substrate 11 on the front side for each row. A row is a cell column in the horizontal direction in FIG. The sustain electrodes X and Y are each printed using a transparent conductive film 41 which is generally composed of ITO and a thin film (for example, Cr-Cu-Cr) or photosensitive conductive paste which is generally formed by metal deposition. It is formed of a bus electrode 42 which is produced by lithography or by printing using a conductive paste, and is covered with a dielectric layer 17 having a thickness of about 30 mu m, which is usually made of low melting point glass. The surface of the dielectric layer 17 is provided with a protective film 18 of thousands of angstroms thick, which is usually made of MgO. The address electrodes A are arranged on the glass substrate 21 on the back side, and are usually covered with a dielectric layer 24 having a thickness of about 10 μm. On the dielectric layer 24, one partition wall 29 having a height of about 150 µm and having a straight band in plan view is provided between each address electrode A. By these partitions 29, the discharge space 30 is defined for each subpixel (unit light emitting region) in the row direction and is partitioned. Then, the upper surface of the address electrode A and the side surface of the barrier rib 29 are covered to cover the inner surface of the rear side, and the phosphor layers 28R, 28G, and 28B of three colors of R, G, and B for color display are covered. Is installed. The discharge space 30 is usually filled with a discharge gas containing neon (Ne) as a main component and mixed with xenon (Xe) (normally, the sealing pressure is about 500 Torr), and the phosphor layers 28R, 28G, and 28B are discharged at the time of discharge. It is locally excited by the ultraviolet rays emitted by xenon and emits light. One pixel (pixel) in the PDP illustrated in FIG. 1 is composed of three subpixels arranged side by side in the row direction. The structure within each subpixel is called a cell.

2 shows an example of a drive waveform used in a method of driving an AC plasma display panel by a prior art ADS method. As shown in FIG. 2, the ADS method divides one subfield into an address section and a sustain discharge section. Here again, the address section is a reset section consisting of the first step (step 1), the second step (step 2) and the third step (step 3) and the address scan of the fourth step (step 4) address scan).

In the reset period, the entire erase and write pulses are alternately applied to the two sustain electrodes X and Y to form a constant wall charge in all cells, thereby preparing for a subsequent address scan. The reset section serves to erase data in the previous subfield and to keep all discharge cells in a similar state in order to write image data thereafter. At this time, the pulse applied to the reset section may use a smooth rising pulse if necessary, and reset pulses every several subfields instead of a reset pulse for each subfield. You can also do this. Various waveform variations have been attempted to obtain a better effect in the reset period.

In the address scan period, a discharge is generated in a required pixel by sequential scan pulses applied to the address electrode pulse and the Y electrode to form wall charges so that the discharge occurs only in the selected cell during the sustain discharge period. That is, it is a section for writing the video data.

In the sustain discharge section, pulses are alternately applied to the X and Y electrodes as shown in FIG. 2 so that a discharge is generated between the X and Y electrodes in a cell selected in the address section and having wall charges formed thereon. The pulse applied during the sustain period, that is, the waveform of the sustain pulse is a square wave, and may be applied by changing the frequency or duty ratio of the sustain pulse according to the driving method. At this time, no voltage is applied to the address electrode. At this time, in the prior art, no pulse is applied to the address electrode and maintained at a constant potential. Phosphors are excited by vacuum ultraviolet rays emitted from the discharges generated between the both sustain electrodes X and Y so that the visible light is emitted only from the cells where the wall charges are written in the address period. Will be displayed

In the case of the AC PDP, it is common to have eight subfields of different brightness for one TV field (typically 16.7 ms) representing an image for 256-gradation representation as shown in FIG. Each subfield has a length of sustain discharge intervals corresponding to 20, 21, 22, 23, 24, 25, 26, and 27, and a combination of these subfields can express 256 (= 28) gray scales. .

In order to implement a low cost high quality TV by mass production using such a conventional AC PDP, it is desirable to further reduce the power consumption by lowering the discharge start voltage during sustain discharge, improving luminance, and increasing luminance efficiency. Do.

In order to overcome this problem, in the present invention, unlike the prior art in which the address electrode is maintained at a constant voltage during sustain discharge, a low discharge is applied by applying a pulse having a predetermined voltage value, frequency and duty ratio to the address electrode. A driving method of a plasma display having a starting voltage, high luminance and high luminance efficiency is proposed. The pulses of the present invention applied to the address electrodes are not correlated with the pulses applied to the sustain electrodes X and Y, and have a characteristic of being independently applied to the sustain pulses. In addition, the pulse of the present invention is not intended to cause discharge but is a pulse for assisting driving in the sustain section. Therefore, in order to prevent the discharge between the sustain electrode and the address electrode from occurring, it is applied with a magnitude less than the discharge start voltage.

1 shows an example of a general AC plasma display panel.

2 shows an example of a drive waveform used in a method of driving an AC plasma display panel by a prior art ADS method.

3 shows an example of a method of dividing a field for gray scale representation of an AC plasma display panel according to a prior art ADS method.

4 shows an embodiment of a driving waveform by the driving method of the plasma display panel of the present invention.

5 shows the change of the discharge start voltage according to the voltage magnitude and frequency of the pulse applied to the address electrode during the sustain discharge period of the present invention.

6 shows a change in luminance according to the voltage magnitude and frequency of the pulse applied to the address electrode during the sustain discharge period of the present invention.

7 shows a change in relative luminance efficiency of sustain discharge according to the voltage magnitude and frequency of the pulse applied to the address electrode during the sustain discharge period of the present invention.

<Explanation of symbols for the main parts of the drawings>

11: front panel 17: dielectric layer

18: protective film 21: the back plate

A: address electrode 24: dielectric layer

28R, 28G, 28B: Phosphor 29: Bulkhead

30: interlayer

A driving method of a plasma display according to an aspect of the present invention for achieving the above object, has a plurality of pixels for representing an image, the pixel includes one or more discharge cells of different colors, the discharge cell In order to express gradation in an AC plasma display panel having a pair of sustain electrodes and an address electrode, one field is divided into several subfields having different times, and each subfield is divided into an address section and a sustain discharge section. The method is a method of driving an AC plasma display, the method comprising applying a pulse having a predetermined frequency and duty ratio to the address electrode during the sustain discharge period.

In the driving method of the plasma display of the present invention, it is preferable that the pulse applied to the address electrode is a low voltage in a range in which no discharge occurs with any one of the pair of sustain electrodes.

In addition, in the driving method of the plasma display of the present invention, the pulse applied to the address electrode is preferably a frequency in the range of 1 KHz to 1 GHz.

Further, in the plasma display driving method of the present invention, the pulse applied to the address electrode can adjust the duty ratio.

Further, in the plasma display driving method of the present invention, a higher effect can be obtained when the voltage of the pulse applied to the address electrode is 20V or more and 200V or less.

Further, in the method of driving the plasma display of the present invention, a higher effect can be obtained when the pulse applied to the address electrode is 100 KHz or more.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention. First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are denoted by the same reference numerals as much as possible even if displayed on the other drawings.

4 shows an embodiment of a driving waveform by the driving method of the plasma display panel of the present invention. During the sustain period, sustain discharge is generated between sustain electrodes X and Y, and discharge between the sustain electrode and the address electrode is preferably avoided. Therefore, Vas, the peak voltage of the pulse at this time, is sustain electrode X and address electrode A, sustain. The discharge is set so that no discharge occurs between the electrode Y and the address electrode A. FIG. In addition, the frequency f of the pulse may vary regardless of the frequency of the sustain discharge pulse, and may be used from a low frequency (about 1 KHz) to a high frequency (about 1 GHz). The duty ratio of the pulses can also be varied. The change of the characteristic according to the change of the pulse frequency is described in more detail below.

5 shows the change of the discharge start voltage according to the voltage magnitude and frequency of the pulse applied to the address electrode during the sustain discharge period of the present invention. As described above, the voltage magnitude of the pulse was varied in a range in which no discharge occurred between the sustain discharge and the address electrode. At this time, it can be observed that the discharge start voltage is lowered as the pulse frequency increases as shown in FIG. 5. The decrease in the discharge start voltage with this frequency increase was more pronounced when the pulse voltage was high (about 20 V or more).

6 shows a change in luminance according to the voltage magnitude and frequency of the pulse applied to the address electrode during the sustain discharge period of the present invention. Also in this case, it was observed that the luminance increased with increasing frequency. Also, when the pulse voltage is high, the increase in brightness with the increase of the frequency is more prominent, and the increase in brightness due to the increase in the pulse voltage at all frequencies is also remarkable.

7 shows a change in relative luminance efficiency of sustain discharge according to the voltage magnitude and frequency of the pulse applied to the address electrode during the sustain discharge period of the present invention. It was observed that the luminance efficiency increased as compared with the case where no pulse was applied to the address electrode (in the case of 0V in the figure) over a region up to 200KHz at a low frequency around 25KHz.

The present invention is based on the above observations, and is intended to achieve luminance, increase in luminance efficiency and reduction in discharge voltage by applying pulses to address electrodes that are not used during the sustain period.

As described above, in the detailed description of the present invention, specific embodiments have been described, but various modifications can be made without departing from the scope of the present invention. For example, the shape of the pulse may be replaced by a pulse such that a voltage of a normal part, such as a ramp waveform and a log waveform, changes over time, not a simple square wave. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the claims below, but also by the equivalents of the claims.

According to the plasma display panel driving method of the present invention, the luminance of the plasma display panel can be further increased, the luminance efficiency can be improved, the driving voltage can be reduced during the sustain period, and the plasma display panel having a wide driving margin can be obtained. The plasma display device can reduce the power consumption.

Claims (6)

In order to express gradation in an AC plasma display panel having a plurality of pixels for representing an image, the pixels include one or more discharge cells having different colors, and the discharge cells have a pair of sustain electrodes and address electrodes. In a method of driving an alternating-current plasma display in which one field is divided into several subfields having different times from each other, and each subfield has an address period and a sustain discharge period. And applying a pulse having a predetermined frequency and duty ratio to the address electrode during the sustain discharge period. The method of claim 1, And a pulse applied to the address electrode is a low voltage in a range in which no discharge occurs with any one of the pair of sustain electrodes. The method according to claim 1 or 2 And a pulse applied to the address electrode is a frequency in a range of 1 kHz to 1 GHz. The method according to claim 1 or 2, And a pulse applied to the address electrode can adjust a duty ratio. The method of claim 2, And a voltage of a pulse applied to the address electrode is 20V or more and 200V or less. The method of claim 3 And a pulse applied to the address electrode is 100 KHz or more.