KR100735737B1 - Method and device for improving contrast ratio of AC plasma display - Google Patents

Abstract

The present invention relates to a method and apparatus for improving the contrast ratio of an AC plasma display panel using an X electrode (hereinafter referred to as a 'PDP'), wherein the contrast ratio is improved during an initialization period for driving an AC PDP according to the present invention. The method includes applying a predetermined voltage between the X electrode and the Y electrode to erase wall charge remaining in the sustain electrode; And forming an initial wall charge by applying a lamp pulse to the Y electrode and applying a predetermined voltage to the X electrode to generate a discharge between the address electrode and the Y electrode. There is an effect of improving the contrast ratio of the plasma display panel by removing the light emitted during the initialization period of the cell that did not discharge.

AC PDP, Reset, Ramp Waveform, Contrast Ratio, Counter Reset Reset Discharge

Description

Method and device for improving contrast ratio of AC plasma display {METHOD AND APPARATUS FOR IMPROVING CONTRAST RATIO IN AC PLASMA DISPLAY PANEL}

1 is a model diagram showing a light emission principle of a plasma display panel (PDP);

2 is a cross-sectional view showing a counter electrode structure of a PDP;

3 is a cross-sectional view showing a surface discharge electrode structure of a PDP;

4 is a cross-sectional view showing a transmissive electrode structure of a PDP;

5 is a cross-sectional view showing a reflective electrode structure of a PDP;

6 is a perspective view showing the electrode structure of the surface discharge-reflective-3 electrode PDP;

7 is a waveform diagram showing waveforms applied to each electrode for driving an AC PDP in the prior art;

8 is a waveform diagram showing a 256 gradation display method in the ADS driving method of a general AC PDP;

9 is a waveform diagram showing waveforms applied to each electrode to improve contrast ratio of an AC PDP according to a first embodiment of the present invention;

10 is a circuit diagram of a driving circuit for generating the waveform of FIG. 9;

FIG. 11 is a waveform diagram showing waveforms applied to each electrode to improve contrast ratio of an AC PDP according to a second embodiment of the present invention; FIG.

12 is a waveform diagram showing waveforms applied to each electrode to improve contrast ratio of an AC PDP according to a third embodiment of the present invention;

FIG. 13 is a waveform diagram showing waveforms applied to each electrode to improve contrast ratio of an AC PDP according to a fourth embodiment of the present invention; FIG.

14 is a waveform diagram showing waveforms applied to each electrode to improve contrast ratio of an AC PDP according to a fifth embodiment of the present invention;

15 is a waveform diagram showing waveforms applied to each electrode to improve contrast ratio of an AC PDP according to a sixth embodiment of the present invention;

16 is a waveform diagram showing waveforms applied to each electrode to improve contrast ratio of an AC PDP according to a seventh embodiment of the present invention;

17 is a waveform diagram showing waveforms applied to each electrode to improve contrast ratio of an AC PDP according to an eighth embodiment of the present invention;

18 is a waveform diagram showing waveforms applied to each electrode to improve contrast ratio of an AC PDP according to a ninth embodiment of the present invention;

19 is a waveform diagram showing waveforms applied to each electrode to improve contrast ratio of an AC PDP according to a tenth embodiment of the present invention;

20 is a waveform diagram showing waveforms applied to each electrode to improve the contrast ratio of an AC-type PDP according to an eleventh embodiment of the present invention;

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

1: front substrate 2: back substrate

3: X electrode 4: Y electrode

5: bulkhead 6: phosphor

7: transparent ITO electrode 8: metal electrode

9 address electrode 10 dielectric layer

11: MgO protective film

The present invention relates to a method and apparatus for improving the contrast ratio of an AC plasma display (Plasma Display Panel, hereinafter referred to as a 'PDP') using an X electrode, and more particularly, to initialize an AC PDP (also referred to as a 'reset'). In order to improve the decrease in the contrast ratio caused by the discharge during the period T1, not only the predetermined reset waveform is applied to the Y electrode 4 during the initialization period T1, but also the X electrode 3 is also prescribed. A method of improving the contrast ratio by inducing discharge between the address electrode 9 and the Y electrode 4 by applying a voltage of is proposed.

In general, PDPs are classified into various types based on the electrode structure and the driving method thereof. The electrode structure of PDP is classified into a DC type, an AC type, and a hybrid type in which a DC type and an AC type are combined. In addition, it can be classified into a two-electrode structure and a three-electrode structure according to the number of electrodes installed in the cell. In addition, the electrode may be classified into a counter electrode and a surface discharge electrode structure according to the arrangement of the electrodes forming the discharge. In FIG. 2, an example of the counter electrode structure is illustrated, and FIG. 3 illustrates an example of the surface discharge electrode structure. In addition, the electrode structure of the PDP is classified into a transmissive type as shown in FIG. 4 and a reflective type as shown in FIG. 5 based on the application position of the phosphor.

1 is a schematic diagram showing the light emission principle of a PDP. As shown, the PDP is a flat panel display device that displays characters or graphics using visible light generated by vacuum ultraviolet rays generated by discharging an inert gas to excite phosphors.

2 is a cross-sectional view showing an example of the counter electrode structure of the PDP. As shown, in the case of the counter electrode structure, two sustain electrodes forming a discharge are positioned on the front substrate and the rear substrate, respectively, so that the discharge is formed on the vertical axis of the panel.

3 is a cross-sectional view showing an example of the surface discharge electrode structure of the PDP. As shown, it refers to an electrode structure in which the X and Y electrodes, which are two sustain electrodes forming a discharge, are positioned on the same substrate so that the discharge is formed on one plane of the panel.

4 is a cross-sectional view showing an example of a transmissive electrode structure of a PDP. The transmissive electrode structure has the advantage of being easy to manufacture, but has a disadvantage in that the luminance variation is large due to the printing surface state of the phosphor.

5 is a cross-sectional view illustrating a reflective electrode structure of a PDP. Reflective electrode structure has the advantage of increasing the brightness by increasing the coating area of the phosphor, but there is a difficulty in the technique of phosphor coating. However, the development of thick film printing technology has solved a lot of phosphor coating problems, and nowadays, reflective electrode structures have been widely used. At present, AC-type PDPs with surface discharge-reflective-three-electrode structures outperform other structures, and each company adopts this structure.

6 is a perspective view showing the structure of the surface discharge-reflective-3 electrode PDP. As shown, an indium tin oxide (ITO) (hereinafter referred to as a transparent electrode), which is a transparent conductor, is disposed side by side on the front substrate 1 to form a surface discharge. The rear substrate has an address electrode 9 and After the partitions 5 are arranged in parallel, the phosphor is coated.

In particular, a metal electrode of Cr-Cu-Cr (hereinafter referred to as 'metal electrode') 8 was added to the transparent electrode on the front substrate 1 to improve conductivity. In the case of the transparent electrode 7 which is directly involved in the discharge formation, when a large panel is used, one line becomes very long and the line resistance increases, thereby preventing a voltage drop. Such a transparent electrode 7 and a metal electrode 8 are referred to as a discharge sustaining electrode.

In general, unlike the direct current type PDP in which the electrode is directly exposed to the discharge plasma, in the case of the AC type PDP, the electrode is indirectly coupled with the plasma through the dielectric layer 10. This difference leads to a difference in discharge phenomenon, and in the case of an AC PDP, charged particles formed by discharge are accumulated in the dielectric layer 10.

That is, electrons are accumulated in the dielectric layer 10 on the positively charged electrode, and ions are accumulated in the dielectric layer 10 on the negatively charged electrode. The potential formed through this phenomenon is called wall charge, and since the wall charge is formed to be reversed in polarity with the electric field applied from the outside, the electric field applied from the outside cancels out, and when wall charge starts to form, the potential applied to the gas in the cell Will decrease.

Therefore, when a sufficiently large wall charge is formed, the discharge is erased because the potential applied to the gas decreases below the voltage at which the discharge can be maintained. However, if the voltage applied to the external electrode is changed after the wall charge is formed, discharge is possible even at low external voltage because the electric field due to the wall charge and the electric field due to the external applied voltage are added. It is called driving by memory function.

The AC PDP has a memory function by wall charges accumulated in the dielectric 10 as described above. The dielectric 10 in the cell in which the discharge has been previously formed is externally formed by the charged particles forming the wall charge on the dielectric 10. If the applied voltage is reversed, it may cause discharge at a lower voltage than in the case of cells without wall charge. This memory function is very useful for PDP, which is a gas discharge display device that adopts a row driving method, to drive a large panel.

As shown in FIG. 6, in the case of an alternating current PDP, the dielectric layer 10 for forming a capacitively coupled discharge includes an X electrode 3 composed of a transparent ITO electrode 7 and a metal electrode 8 of Cr-Cu-Cr. And the Y electrode 4 and the address electrode 9 are covered. The dielectric layer 10 generally used is a borosilicate series, has a low secondary electron emission coefficient, and has a short lifetime due to sputtering by ions generated during plasma formation. In order to protect from plasma, an oxide-based thin film such as magnesium oxide is coated on the dielectric layer 10 as a protective film (hereinafter referred to as an MgO protective film) 11. The magnesium oxide (MgO) exhibits low voltage discharge characteristics because it has good sputter resistance and high secondary electron emission coefficient. However, since the thickness of the MgO passivation layer should be thin and the surface characteristics should be excellent, it is difficult to form through thick film printing and is usually manufactured by a thin film process by vacuum deposition.

In the case of the partition 5, a height of about 100 to 200 μm is required to form a discharge distance and a volume. By the thick film printing method and the electrophoresis method, the partition 5 of several tens of micrometers in thickness is formed.

In addition, although two electrodes are possible to form a discharge, an electrode structure having three electrodes is generally used as shown in FIG. 6. In the case of the AC-type PDP, an address electrode 9 is introduced to separate the selective discharge and sustain discharge from the X electrode 3 and the Y electrode 4, which are sustain electrodes, to improve the addressing speed.

7 is a waveform diagram showing waveforms applied to each electrode in the prior art for driving an AC PDP. FIG. 7 is applied to the X electrode 3, the Y electrode 4 and the address electrode line 9 composed of the transparent ITO electrode 7 and the metal electrode 8 of FIG. 6 in order to display information on a general AC PDP. The voltage waveform is shown in the figure. By using a ramp waveform in which the voltage increases with time in the initialization period T1, a strong discharge (discharge of high plasma density due to a strong electric field) is not generated during the initialization period T1. Its characteristic is that it induces a weak discharge (low plasma density discharge by a weak electric field) to occur. As a result, the generation of unnecessary light during the initialization period T1 is reduced to increase the contrast ratio, and a large amount of wall charges can be accumulated on the address electrode to lower the discharge voltage of the address.

In terms of time, the waveform of FIG. 7 may be divided into an initialization period T1, a writing period T2, and a sustain period T3.

In the initialization period T1, a pulse is applied to the sustain electrode line to make the entire uneven panel uniform while the AC PDP displays the previous information. At this time, no voltage is applied to the address electrode 9 or a constant voltage is maintained. The waveform of FIG. 7 has a great feature in the initialization period T1. A large feature of the initialization period T1 of FIG. 7 is the application of the ramp pulse V _e to the X electrode 3 to cause erasing discharge first, and then to the Y electrode 4 to rise with a constant slope ( RP) is applied several times to induce a weak discharge to reduce the amount of light from the initialization period, and to apply a high voltage to leave a lot of wall charges accumulated to reduce the voltage of the address discharge much.

In the lower portion of the voltage, the self-erasing discharge occurs when the voltage of the Y electrode 4 is rapidly lowered like a square wave due to the above wall charge generated at the rising portion of the voltage. When the wall charges are maintained, sustain discharges occur during the sustain period T3 even in cells in which no address discharge has occurred. In order to prevent such an effect, as shown in FIG. 7, only a voltage which does not generate a self-erasing discharge is suddenly lowered like a square wave, and the lower is induced by applying a voltage (-RP) falling with a constant slope to induce a weak discharge. Discharge does not occur in the sustain period T3 without the address discharge.

In the writing period T2 or the address period, information to be displayed by the voltage difference between the line of the Y electrode 4 and the address electrode 9 is written by stacking wall charges after the write discharge.

In the sustain period T3, alternating voltages are applied to both the X electrode 3 and the Y electrode 4, which are both sustain electrode lines, to emit visible light only in the cell written in the write period T2, thereby displaying information. In the sustain period T3, the waveforms of the X electrode 3 and the Y electrode 4 pulses, which are both sustain electrode lines, are square waves, and the frequency, duty ratio, and magnitude of the sustain pulse are changed depending on the driving method. do.

In the driving method using the drive waveform of such a PDP, discharge is not generated in the sustain period T3 while cells not written in the write period T2 are discharged in the write initialization period T1, so that unnecessary light is emitted and low contrast ratio is achieved. Occurs.

8 is a waveform diagram showing a gray scale display method in the ADS driving method of a general AC PDP. In FIG. 8, the stimulus with respect to the brightness perceived by the vision is proportional to the intensity of the light source, but also proportional to the time of continuous stimulation with time. Therefore, the PDP gray scale display method uses a kind of pulse width modulation that adjusts the emission time.

For example, 256 gray scale display is divided into 8 subfields of pulse ratio 1: 2: 4: 8: 16: 32: 64: 128 to generate a discharge in each subfield corresponding to the desired gray scale. Gradation can be achieved. 1 is called the least significant bit, 128 is the most significant bit, and 8 subfields are referred to as 8 subfields.

The figure shows the configuration of the initialization period T1, the address period T2 and the sustain period T3 in eight subfields for 256 gray scale display in the case of the maximum light emission time. In the initialization period T1 and the address period T2, all subfields are set to the same time, while the duration of the sustain period has a ratio of 1: 2: 4: 8: 16: 32: 64: 128, respectively. .

Ideally, light should be emitted only in the sustain period T3, and the light emitted during the non-emission period initialization period T1 is a factor that worsens the contrast ratio of the image because it is not a light reflecting the image to be expressed.

In order to improve this, the prior art improves the contrast ratio by using a method of applying a waveform having a constant slope between the X electrode 3 and the Y electrode 4 in the initialization period as described above, but there is a limitation.

The present invention focuses on the fact that the cells having no discharges in all the subfields do not cause reset discharges and do not cause reset discharges during the initialization period T1 when the black color is to be displayed. A new contrast ratio improvement method is proposed.

The present invention provides a solution to this problem, by applying a predetermined voltage to the X electrode in the initialization period to reset discharge to the Y electrode and the address electrode in the initialization period, the cells that did not discharge in all the sub-field reset reset discharge The present invention aims to improve contrast ratio by discharging only cells that have had discharges in all subfields, without emitting background light when displaying black.

The present invention according to one aspect for achieving the above object, has a plurality of pixels for displaying an image, the pixels are initialized for driving the AC PDP having two sustain electrodes and one address electrode, respectively A method of improving the contrast ratio during a period of time, the method comprising: removing a wall charge remaining on the sustain electrode by applying a predetermined voltage to the sustain electrode; And forming a reset discharge between the address electrode and the scan electrode by applying a predetermined voltage to the sustain electrode.

In the method for improving the contrast ratio of an AC plasma display according to the present invention, the erasing of the wall charges may include applying a voltage rising over time to the Y electrode of the sustain electrodes.

In the method for improving the contrast ratio of an AC plasma display according to the present invention, the initial wall charge may be formed by applying a pulse voltage to the X electrode.

In the method of improving the contrast ratio of an AC plasma display according to the present invention, the voltage applied to the X electrode is applied after the step of erasing the wall charge is completed.

In addition, in the contrast ratio improvement method of the AC plasma display according to the present invention, the voltage applied to the X electrode is, after the voltage is applied to the Y electrode to form the weak discharge, before the discharge by the voltage is started. Or at the same time as when the voltage is applied to the Y electrode.

Further, in the contrast ratio improvement method of the AC plasma display according to the present invention, the voltage applied to the X electrode is Y after completion of discharge with the address electrode by applying the voltage to the Y electrode to form the weak discharge. The magnetic erasing discharge generated in the process of removing the voltage to the electrode is characterized in that it is applied until the end.

According to another aspect of the present invention, there is provided a driving apparatus for driving an AC PDP having a plurality of pixels for displaying an image, each pixel having two sustain electrodes and one address electrode. An apparatus for improving contrast ratio, comprising: an initialization erase driver configured to erase a wall charge remaining on the sustain electrode by applying a predetermined voltage to the sustain electrode; An initialization driver configured to apply a predetermined voltage to the Y electrode and the address electrode to form a weak discharge by the initial wall charge; And a driving unit configured to apply a predetermined voltage to the X electrode to form a discharge between the Y electrode and the address electrode.

According to another aspect of the present invention, there is provided a plurality of pixels for displaying an image, each pixel having an AC PDP having two sustain electrodes, an X electrode and a Y electrode, and one address electrode. CLAIMS 1. A method of improving contrast ratio during an initialization period for driving a light source, the method comprising: erasing wall charge remaining in a sustain electrode by applying a predetermined voltage between the X electrode and the Y electrode; Applying a predetermined voltage to the X electrode, and applying a predetermined voltage between the address electrode and the Y electrode to erase the wall charge remaining between the address electrode and the Y electrode; And forming initial wall charges by applying a predetermined voltage to the X electrode and the Y electrode, and applying a higher voltage to the Y electrode to generate a discharge between the address electrode and the Y electrode. It is characterized by.

In the method of improving the contrast ratio of an AC plasma display according to the present invention, the step of erasing wall charge remaining between the address electrode and the Y electrode may include applying a voltage that rises with time between the sustain electrodes. It features.

In addition, in the contrast ratio improvement method of the AC plasma display according to the present invention, the voltage of the pulse type applied to the address electrode is started to be applied after the erase discharge is terminated between the sustain electrodes, and an initialization pulse is applied to the Y electrode. It is characterized in that the authorization is terminated before the authorization.

In addition, in the contrast ratio improvement method of the AC plasma display according to the present invention, the voltage of the pulse type applied to the X electrode may be maintained after the voltage of the erase pulse is maintained after the erase discharge is terminated or after the erase discharge is terminated. It is characterized by the start of the application.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In adding reference numerals to components of each drawing, it should be noted that the same components are denoted by the same reference numerals as much as possible even if they are shown in different drawings.

FIG. 9 is a diagram showing waveforms of voltages applied to respective electrodes in order to improve contrast ratios of an AC PDP according to a first embodiment of the present invention. With the exception of pulse (V _b) applied to the X electrode 3, after applying the erase pulse (V _e) in the initialization (T1), the process is the same as the drive waveform Matsushita Corporation Japan.

In FIG. 9, the waveform diagram shows an X electrode (3) for initializing each cell by the period of applying the erasing pulse (V _e ) to generate an erase discharge, and the counter discharge of the address electrode (9) and the Y electrode (4). ), the period, the address electrode for applying a pulse (V _b) is applied and the Y electrode 4 is provided in the ramp-up waveform having a voltage higher than the pulse (V _b) applied to the X electrode 3, a ramp waveform (RP) the It consists of a section in which a ramp-down waveform lamp pulse (-RP) is applied to generate a weak self-erasing discharge between (9) and the Y electrode 4 to erase the wall charges only a little.

Here, the voltage V _b applied to the X electrode is applied before the discharge occurs between the X electrode and the Y electrode by the voltage to the Y electrode in order to improve the contrast ratio by inducing the discharge between the address electrode and the Y electrode. Since a voltage is applied to the X electrode, a discharge occurs between the address electrode and the Y electrode. Due to the discharge, wall charges having negative polarities are accumulated at the X and Y electrodes, and wall charges having positive polarities are accumulated at the address electrodes.

Accordingly, it is an address voltage (V _a) to sustain period T3 because this does not happen if this is not the address discharge in the state formed in the interval T1 the wall charges on the X electrode and the Y electrode. The wall charges formed in the T1 section accumulate negatively charged charges in the sustain electrode and the positively charged charges in the address electrode, and thus discharge even when the sustain pulses V _sx and V _sy are applied in the T3 section. It is not formed. Even when the erase pulse V _e of the next subfield is applied, no discharge occurs, positive charges are accumulated at the address electrode, and negative charges are accumulated at the Y electrode. ) Does not occur. Thus, the present invention determines the discharge in the initialization section T1 of the next subfield according to whether the address section T2 is discharged or not. If there is a discharge in the address section T2, a discharge occurs in the initialization section T1 of the next subfield, but if there is no discharge in the address section T2, no discharge occurs in the initialization section T1 of the next subfield. . That is, if there is no discharge in the address section in all the subfields, no discharge occurs in the initialization section T1 until discharge occurs in the address section in the subsequent subfields.

In more detail, when a predetermined voltage is applied to the X electrode before the discharge occurs between the X electrode and the Y electrode by applying the lamp pulse RP of the ramp-up waveform, the discharge does not occur between the X electrode and the Y electrode. Instead, a discharge occurs between the address electrode and the Y electrode. At this time, positive charges are stored in the address electrode, and negative charges are stored in the X electrode and the Y electrode. Therefore, if no discharge occurs in the address section, no discharge occurs in the sustain section. Thus, the wall charge distribution formed in the above process is maintained, and the wall charge distribution does not occur because the polarity is opposite to the voltage applied between the address electrode and the Y electrode even in the initializing section T1 of the subsequent subfield. In the subsequent process, the discharge does not continue and the wall charge distribution of the process is maintained. Due to this wall charge characteristic, when no discharge occurs in the address period of all subfields, no background light is generated when black is to be displayed.

11 is a view showing a drive waveform according to a second embodiment of the present invention. The waveforms applied to the address electrode 9, the X electrode 3, and the Y electrode 4 are different from those of the first embodiment above, and the X electrode is maintained until the T2 section by keeping the voltage after applying the erase pulse V _e . It is characterized by the fact that a voltage is applied. That is, the erase pulse V _e and the bias pulse V _b applied to the X electrode 3 were used as one pulse. Therefore, the number of driving circuits is reduced and the driving method is simplified. Since the rest of the waveforms are the same as in the first embodiment, detailed descriptions are omitted. As shown in the first embodiment, a ramp-up ramp pulse RP having a ramp-up waveform is applied to the Y electrode 4 so that the X electrode It is characterized in that a discharge is generated between the address electrode 9 and the Y electrode 4 by applying a voltage V _b to the X electrode 3 before the discharge occurs between the (3) and the Y electrode 4. There is this.

12 is a view showing a drive waveform according to a third embodiment of the present invention. The waveforms applied to the address electrode 9, the X electrode 3 and the Y electrode 4 are different from those of the first embodiment above, and the ramp pulse RP of the ramp-up waveform is applied to the Y electrode 4. Is characterized in that the voltage of the pulse V _b1 applied to the X electrode is smaller than the voltage of the pulse V _b applied to the X electrode while the ramp pulse (-RP) having a rampdown waveform is applied to the Y electrode 4. to be. Since the operation of each part of the waveform in the remaining portion is the same as in the first embodiment, detailed descriptions are omitted, and the X-electrode is applied to the Y electrode 4 by applying a ramp-up ramp pulse RP to the Y electrode 4 as in the first embodiment. It is characterized in that a discharge is generated between the address electrode 9 and the Y electrode 4 by applying a voltage V _b1 to the X electrode 3 before the discharge occurs between the (3) and the Y electrode 4. There is this.

13 is a view showing a drive waveform according to a fourth embodiment of the present invention. The waveforms applied to the address electrode 9, the X electrode 3 and the Y electrode 4 are different from those of the first embodiment above, and the ramp pulse RP of the ramp-up waveform is applied to the Y electrode 4. The voltage of the pulse V _b2 applied to the X electrode during the period is greater than the voltage of the pulse V _b applied to the X electrode while the ramp pulse (-RP) having a rampdown waveform is applied to the Y electrode 4. to be. Since the operation of each part of the waveform in the remaining portion is the same as in the first embodiment, detailed description is omitted, and as shown in the first embodiment, a ramp-up ramp pulse RP having a ramp-up waveform is applied to the Y electrode 4 so that X Before discharge occurs between the electrode 3 and the Y electrode 4, a voltage V _b2 is applied to the X electrode 3 so that the discharge occurs between the address electrode 9 and the Y electrode 4. There is a characteristic.

14 is a view showing a drive waveform according to a fifth embodiment of the present invention. The waveforms applied to the address electrode 9, the X electrode 3 and the Y electrode 4 are different from those in the first embodiment above, and the ramp-up ramp RP and ramp-down of the ramp-up waveform are applied to the Y electrode 4. The voltage of the pulse V _b3 applied to the X electrode while the ramp pulse (-RP) of the type is applied is greater than the voltage of the pulse V _b applied to the X electrode in the address period T2. Since the operation of each part of the waveform in the remaining portion is the same as in the first embodiment, detailed descriptions are omitted, and the X-electrode is applied to the Y electrode 4 by applying a ramp-up ramp pulse RP to the Y electrode 4 as in the first embodiment. It is characterized in that a discharge is generated between the address electrode 9 and the Y electrode 4 by applying a voltage V _b3 to the X electrode 3 before the discharge occurs between the (3) and the Y electrode 4. There is this.

15 illustrates driving waveforms according to a sixth exemplary embodiment of the present invention. The waveforms applied to the address electrode 9, the X electrode 3 and the Y electrode 4 are different from those in the first embodiment above, and the ramp-up ramp RP and ramp-down of the ramp-up waveform are applied to the Y electrode 4. The voltage of the pulse V _b4 applied to the X electrode while the ramp pulse (-RP) of the type is applied is smaller than the voltage of the pulse V _b applied to the X electrode 3 in the address period T2. to be. Since the operation of each part of the waveform in the remaining portion is the same as in the first embodiment, detailed descriptions are omitted, and the X-electrode is applied to the Y electrode 4 by applying a ramp-up ramp pulse RP to the Y electrode 4 as in the first embodiment. It is characterized in that a discharge is generated between the address electrode 9 and the Y electrode 4 by applying a voltage V _b4 to the X electrode 3 before the discharge occurs between the (3) and the Y electrode 4. There is this.

16 is a view showing a drive waveform according to the seventh embodiment of the present invention. The waveforms applied to the address electrode 9, the X electrode 3, and the Y electrode 4 are different from those of the first embodiment, and the scan voltage applied to the Y electrode in the address period T2 is maintained at 0V. It is characterized by scanning by applying a negative pulse (V _sc ). Since the rest of the waveforms are the same as in the first embodiment, detailed descriptions are omitted. As shown in the first embodiment, a ramp-up ramp pulse RP having a ramp-up waveform is applied to the Y electrode 4 so that the X electrode It is characterized in that a discharge is generated between the address electrode 9 and the Y electrode 4 by applying a voltage V _b to the X electrode 3 before the discharge occurs between the (3) and the Y electrode 4. There is this.

17 illustrates driving waveforms according to an eighth embodiment of the present invention. The waveforms applied to the address electrode 9, the X electrode 3 and the Y electrode 4 are different from those of the seventh embodiment above, and the voltage of the ramp pulse (-RP) of the ramp down waveform applied to the Y electrode is different. It is characterized by a reduction to negative voltage (-V _w ). Since the rest of the waveforms are the same as in the seventh embodiment, detailed descriptions are omitted, and as shown in the first embodiment, a ramp-up ramp pulse RP having a ramp-up waveform is applied to the Y electrode 4, thereby increasing the X electrode. It is characterized in that a discharge is generated between the address electrode 9 and the Y electrode 4 by applying a voltage V _b to the X electrode 3 before the discharge occurs between the (3) and the Y electrode 4. There is this.

18 illustrates driving waveforms according to a ninth embodiment of the present invention. Address electrode 9, the waveform acting on the X electrode 3 and Y electrode 4 is different from the first embodiment above, and the X electrode after applying the X electrode 3, the erase pulse (V _e) Ramp-up pulse RP of ramp-up waveform is applied, and spherical pulse V _b5 is applied to Y electrode to cause initializing discharge between address electrode 9 and X electrode 3 and ramp to X electrode 3. The down waveform ramp pulse (-RP) is applied to cause weak self-erasing discharge between the address electrode 9 and the X electrode 3. The rest of the waveforms are the same as in the seventh embodiment, so the detailed description is omitted, and a ramp-up ramp pulse RP of ramp-up waveform is applied to the X electrode between the X electrode 3 and the Y electrode 4. It is characteristic that a discharge occurs between the address electrode 9 and the X electrode 3 by applying a voltage V _b5 to the X electrode 3 before the discharge occurs.

19 illustrates driving waveforms according to a tenth exemplary embodiment of the present invention. The waveforms applied to the address electrode 9, the X electrode 3, and the Y electrode 4 are different from those of the ninth embodiment above, and the X electrode is maintained until the T2 section by maintaining the voltage after applying the erase pulse V _e . It is characterized by the fact that a voltage is applied. That is, the erase pulse V _e and the bias pulse V _b applied to the X electrode 3 were used as one pulse. This reduced the number of drive circuits and simplified the drive method. Since the rest of the operation of each part of the waveform is the same as in the ninth embodiment, a detailed description thereof will be omitted, and as shown in the ninth embodiment, a ramp-up ramp pulse RP of a ramp-up waveform is applied to the X electrode 3. The voltage V _b5 is also applied to the X electrode 3 before the discharge occurs between the Y electrodes 4 so that the discharge occurs between the address electrode 9 and the X electrode 3.

20 illustrates driving waveforms according to an eleventh embodiment of the present invention. Waveforms applied to the address electrode 9, the X electrode 3, and the Y electrode 4 are different from those in the first embodiment above, and are distributed in the cells which have not been discharged in the initialization section T1 of all subfields. In order to erase wall charges between the address electrode 9 and the Y electrode 4, a bias voltage is applied to the X electrode 3 and an erase pulse _Va a is applied to the address electrode 9. When the ramp pulse RP of the ramp-up waveform is applied to the Y electrode 4 by erasing the wall charges of the cells that have not been discharged in all subfields by the erase pulse _{Va a} , the address electrode 9 and the Y electrode 4 Discharge occurs between and initializes. So priming particles were supplied to the cells that had not been discharged for a long time. Since the rest of the waveforms are the same as in the first embodiment, detailed descriptions are omitted. As shown in the first embodiment, a ramp-up ramp pulse RP having a ramp-up waveform is applied to the Y electrode 4 so that the X electrode Before discharge occurs between (3) and Y electrode 4, voltage V _b1 is also applied to X electrode 3 so that discharge occurs between address electrode 9 and Y electrode 4 and the address electrode ( An erase pulse _Va is applied to 9) to initialize cells that did not have discharge in all subfields.

10 is a circuit diagram illustrating an example of a driving circuit capable of generating a waveform applied to each electrode in order to increase the contrast ratio of an AC PDP according to the present invention. In FIG. 10, C1 (address driver), C2 (Y sustain driver), C3 (X sustain driver and X bias driver), C4 (Y initialization driver), C5 (Y scan driver), and C6 (initial erase driver) are conventional Matsushita. The same circuit as the circuit of the company was illustrated. C1 is a circuit that generates a square wave for inducing address discharge together with C5. C2 is a circuit that generates a square wave for sustain discharge of the Y electrode. C3 generates a square wave for sustain discharge of the X electrode, generates a discharge between the address electrode and the Y electrode in the T1 section, and causes negative wall charges to accumulate on the X electrode during the address discharge. C4 is a circuit for applying an initialization pulse to the Y electrode. The upper circuit generates a ramp wave pulse that rises at a constant slope and a rapidly descending pulse like a square wave. This circuit generates a descending ramp wave pulse. C6 is a circuit for generating ramp wave pulses for erasing wall charges caused by sustain discharge of the previous subfield. C5 is a circuit that generates a square wave for sequentially scanning each cell while generating a discharge with the C1 circuit.

As described above, in the detailed description of the present invention has been described with respect to specific embodiments, it should be taken as exemplary, and various modifications are possible without departing from the technical spirit of the present invention. For example, the waveforms applied to the X electrode and the Y electrode illustrated in FIGS. 9 and 11 to 20 may be changed into various other waveforms. Therefore, the scope of the present invention should not be limited to the embodiments described above, but should be defined by the claims below and equivalents thereof.

With the method and apparatus for improving the contrast ratio of an alternating current plasma display using the address electrode of the present invention, it is possible to improve the contrast ratio of the plasma display panel by removing the light emitted during the initialization period of the cell where there is no discharge in all the subfields.

Claims (16)

A method of improving contrast ratio during an initialization period for driving an AC PDP having a plurality of pixels for displaying an image, each pixel having two sustain electrodes, an X electrode and a Y electrode, and one address electrode, Applying a erase pulse to the X electrode; A second step of erasing wall charge between the address electrode and the Y electrode by applying a predetermined voltage to the X electrode and applying an erase pulse to the address electrode after the erase pulse is finished; And The voltage applied in the second step is maintained on the X electrode, and a voltage higher than the voltage applied to the X electrode is applied to the Y electrode after the erasing pulse of the second step is terminated. And a third step of forming initial wall charges by causing a discharge therebetween. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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