KR100667589B1 - Driving Method for Plasma Display Panel - Google Patents

Abstract

The present invention relates to a method of driving a plasma display panel in which a sustain discharge applied between a scan electrode and a sustain electrode in the sustain period is suppressed from being attracted toward the address electrode in the sustain period by reducing the sustain waveform applied to the sustain period. There is.

A driving method of a plasma display panel which expresses an image composed of a plurality of frames by a combination of at least one subfield in which voltage is applied to an address electrode, a scan electrode, and a sustain electrode in a reset period, an address period, and a sustain period. The afterimage prevention voltage Va is applied to the address electrode according to an average picture level in the sustain period of at least one subfield among the subfields.

Plasma Display Panel, Afterimage, Sustain Discharge, Lower Phosphor, Deterioration, Shake

Description

Driving method for plasma display panel {Driving Method for Plasma Display Panel}

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

2 is a diagram illustrating a method of expressing image gradation of a conventional plasma display panel.

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

4 is a view for explaining generation of a bright image generated in a conventional plasma display panel.

5 is a view for explaining the correlation between the content of xenon (Xe) in the discharge cell and the type of discharge.

6 is a view for explaining in more detail the sustain pulse in the sustain period in the conventional driving waveform of FIG.

FIG. 7 is a diagram for explaining aging performed to stabilize a phosphor of a plasma display panel. FIG.

8 is a diagram for explaining discharge fluctuations of the phosphor of the plasma display panel.

9 is a view showing a driving waveform according to the driving method of the plasma display panel of the present invention.

FIG. 10 is a diagram for explaining an example in which a bright afterimage prevention voltage Va is applied to an address electrode according to an average picture level in a sustain period.

11A to 11C are diagrams for explaining a correlation between an average image level of a plasma display panel and a period during which an afterimage prevention voltage Va is applied.

12 is a view for explaining another driving waveform according to the driving method of the plasma display panel of the present invention.

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

10: front substrate 11: rear substrate

100: front glass 101: scan electrode

102 sustain electrode 103 dielectric layer

104: protective layer 110: rear glass

111: partition 112: address electrode

113 phosphor layer 114 white dielectric

The present invention relates to a plasma display panel, and more particularly, to a method of driving a plasma display panel which reduces a bright afterimage by improving a sustain waveform applied to a sustain period.

In general, a plasma display panel is a partition wall formed between a front substrate and a rear substrate to form a unit cell, and each cell includes neon (Ne), helium (He), or a mixture of neon and helium (Ne + He) and The same main discharge gas and an inert gas containing a small amount of xenon (Xe) are filled. When discharged by a high frequency voltage, the inert gas generates vacuum ultraviolet rays and emits phosphors formed between the partition walls to realize an image. Such a plasma display panel has a spotlight as a next generation display device because of its thin and light configuration.

1 illustrates a structure of a general plasma display panel. As shown, the plasma display panel includes a front substrate 10 in which a plurality of sustain electrode pairs formed by pairing a scan electrode 101 and a sustain electrode 102 on a front glass 100 that is a display surface on which an image is displayed. And a rear substrate 11 having a plurality of address electrodes 112 arranged on the rear glass 110 forming the rear surface so as to intersect with the plurality of sustain electrode pairs described above.

The front substrate 10 is made of a scan electrode 101 and a sustain electrode 102, that is, a transparent electrode (a) formed of a transparent ITO material and a metal material to mutually discharge and maintain light emission of the cells in one discharge cell. The scan electrode 101 and the sustain electrode 102 provided as the bus electrode b are included in pairs. The scan electrode 101 and the sustain electrode 102 are covered by one or more dielectric layers 103 that limit the discharge current and insulate the electrode pairs, and the upper surface of the dielectric layer 103 is a magnesium oxide to facilitate the discharge conditions. A protective layer 104 on which calcium (MgO) is deposited is formed.

The rear substrate 11 is arranged in such a manner that a plurality of discharge spaces, that is, barrier ribs 111 of a stripe type (or well type) for forming discharge cells are maintained in parallel. In addition, a plurality of address electrodes 112 which perform address discharge to generate vacuum ultraviolet rays are arranged in parallel with the partition wall 111. On the upper side of the rear substrate 11, R, G, and B phosphor layers 113 emitting visible light for image display during address discharge are formed. A white dielectric 114 is formed between the address electrode 112 and the phosphor layer 113 to protect the address electrode 112 and reflect visible light emitted from the phosphor layer 113 to the front substrate 10.

A method of expressing an image gray level of a plasma display panel having such a structure will be described with reference to FIG. 2.

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

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

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

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

As shown in FIG. 3, the plasma display panel erases a reset period for initializing all cells, an address period for selecting a cell to be discharged, a sustain period for maintaining the discharge of the selected cell, and a wall charge in the discharged cell. It is divided into an erase section for driving.

In the reset period, a rising ramp waveform Ramp-up is simultaneously applied to all scan electrodes in the setup period. This rising ramp waveform causes weak dark discharge within the full discharge cells. By this setup discharge, positive wall charges are accumulated on the address electrode and the sustain electrode, and negative wall charges are accumulated on the scan electrode.

In the set-down period, after the rising ramp waveform is supplied, the ramp ramp starts to fall from the positive voltage lower than the peak voltage of the rising ramp waveform and falls to a specific voltage level below the ground (GND) level voltage. By generating a weak erase discharge in the cells, the wall charges excessively formed in the scan electrode are sufficiently erased. By this set-down discharge, wall charges such that the address discharge can stably occur remain uniformly in the cells.

In the address period, the negative scan signal Scan is sequentially applied to the scan electrodes, and the positive data signal is applied to the address electrodes in synchronization with the scan signal. As the voltage difference between the scan signal and the data signal and the wall voltage generated in the reset period are added, an address discharge is generated in the discharge cell to which the data signal is applied. In the cells selected by the address discharge, wall charges are formed such that a discharge can occur when the sustain voltage Vs is applied. The sustain electrode is supplied with a positive voltage Vz so as to reduce the voltage difference between the scan electrodes during the set-down period and the address period so as to prevent mis-discharge with the scan electrodes.

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

After the sustain discharge is completed, a voltage of an erase ramp waveform (Ramp-ers) having a small pulse width and a low voltage level is supplied to the sustain electrode to erase the wall charge remaining in the cells of the full screen.

The conventional plasma display panel driven as described above has a problem in that an afterimage, that is, an afterimage, is generally generated when a local discharge is generated on the panel display surface.

4 is a view for explaining generation of a bright image generated in a conventional plasma display panel. As shown in FIG. 4, when a predetermined window pattern is displayed at the center portion of the screen, the window pattern intensively discharges a portion 400a of the panel display surface 400. Subsequently, when the entire panel 400b is discharged, the window pattern displayed on the portion 400a of the panel display surface 400 appears as an afterimage 400c. The afterimage 400c may appear due to various reasons, but ultimately, the luminous efficiency of the phosphor may be unstable during cell discharge on the panel display surface. In particular, in recent years, the content of xenon (Xe) in the discharge cells has been increased to improve the characteristics of the discharge efficiency. Increasing the content of xenon (Xe) in the discharge cell further causes the afterimage phenomenon as described above. The correlation between the content of xenon (Xe) in the discharge cell and the discharge type in the discharge cell is as follows.

5 is a view for explaining the correlation between the content of xenon (Xe) in the discharge cell and the type of discharge. As shown, the discharge in the discharge cell with a high content of xenon (Xe) is further attracted toward the address electrode 112. This discharge is described with reference to FIG. 6, which shows the sustain pulse in the sustain section in detail in the conventional driving waveform shown in FIG. 3.

For example, when the sustain voltage Vs is applied to the scan electrode 101 while the ground level voltage is applied to the address electrode 112 and the sustain electrode 102, the sustain discharge is generated by the scan electrode 101. On the contrary, when the sustain voltage Vs is applied to the sustain electrode 102 while the ground level voltage is applied to the address electrode 112 and the scan electrode 101, the sustain discharge by the sustain electrode 102 is generated. . The sustain discharge depends on the surface discharge generated between the scan electrode 101 and the sustain electrode 102. However, as the amount of xenon Xe in the plasma display panel increases, the scan electrode 101 and the sustain electrode ( During the surface discharge between 102, the electric field between the scan electrode 101 and the sustain electrode 102 is dispersed by the strong interaction with the address electrode 112, and the discharge in the discharge cell is attracted to the address electrode 112. That is, as the content of xenon Xe in the discharge cell increases, the discharge in the discharge cell is attracted toward the address electrode 112. As such, as the discharge in the discharge cell is attracted toward the address electrode 112, the lower phosphor of the phosphor of the plasma display panel is deteriorated to shorten the life of the plasma display panel. Here, the above-described phosphor is very unstable at the beginning of the plasma display panel manufacturing process, and in order to stabilize it, aging is performed during the manufacture of the plasma display panel. The phosphor aging will be described with reference to FIG. 7.

FIG. 7 is a view for explaining aging performed to stabilize a phosphor of a plasma display panel. As shown in the drawing, the sidewall phosphor 113a formed on the sidewalls 111 is relatively larger than the lower phosphor 113b among the phosphors 113 of the plasma display panel during aging performed to stabilize the phosphor of the plasma display panel. Deteriorates. Therefore, the sidewall phosphor 113a is more stable than the lower phosphor 113b. As a result, during aging of the plasma display panel, the absolute luminance of the sidewall phosphor 113a is significantly lower than that of the lower phosphor 113b so that the discharge shake width of the sidewall phosphor 113a is smaller than the discharge shake width of the lower phosphor 113b. Looking at the shaking of the discharge as shown in FIG.

8 is a view for explaining discharge fluctuations of the phosphor of the plasma display panel. As illustrated, the lower phosphor among the phosphors of the plasma display panel has a larger discharge shake width than the sidewall phosphor. That is, the time taken to return to a stable state after discharge is relatively longer for the lower phosphor than the sidewall phosphor.

Accordingly, as described above, when the amount of xenon (Xe) is increased and the surface discharge generated between the scan electrode and the sustain electrode in the discharge cell is attracted toward the address electrode, the lower portion that is relatively degraded during aging of the plasma display panel is lowered. The lifetime of the plasma display panel is reduced due to deterioration of the phosphor, and there is a problem in that a bright afterimage is generated on the display surface of the plasma display panel due to the emission of the lower phosphor having a relatively long recovery time after the discharge. .

In order to solve this problem, an object of the present invention is to provide a method of driving a plasma display panel to prevent the discharge is attracted to the address electrode during the surface discharge between the scan electrode and the sustain electrode in the discharge cell in the sustain period.

In order to achieve the above object, the present invention provides a plasma display for displaying an image composed of a plurality of frames by a combination of at least one subfield in which voltage is applied to an address electrode, a scan electrode, and a sustain electrode in a reset period, an address period, and a sustain period. In the method of driving a panel, a bright afterimage prevention voltage Va is applied to the address electrode according to an average picture level in a sustain period of at least one of the plurality of subfields. do.

The bright afterimage prevention voltage Va has a voltage value capable of maintaining a sustain discharge between the scan electrode and the sustain electrode in the sustain period.

The period during which the bright afterimage prevention voltage Va is applied increases as the average image level increases.

When the average image level is the highest level, the bright afterimage prevention voltage Va having the voltage value of the ground GND level is applied to the address electrode in the sustain period.

When the average image level is the lowest level, the bright afterimage prevention voltage Va is applied to the address electrode in the entire sustain period.

An application point of time of the afterimage prevention voltage Va applied to the address electrode in the sustain period may be arbitrarily designated within the sustain period.

Hereinafter, a driving method of the plasma display panel of the present invention will be described in detail with reference to the accompanying drawings.

9 is a view showing a driving waveform according to the driving method of the plasma display panel of the present invention. As shown, the driving waveform according to the driving method of the plasma display panel according to the present invention is to apply the afterimage prevention voltage Va to the address electrode in the sustain period in which the sustain discharge is generated between the scan electrode and the sustain electrode. In this case, the reference for applying the bright afterimage prevention voltage Va to the address electrode is the level of the average picture level. That is, the bright afterimage prevention voltage Va is applied to the address electrode according to the average image level in the sustain period in which sustain discharge is generated between the scan electrode and the sustain electrode.

Here, the afterimage prevention voltage Va has a voltage value capable of maintaining the sustain discharge between the scan electrode and the sustain electrode in the sustain period. In other words, the afterimage prevention voltage Va has a voltage level that does not prevent the surface discharge between the scan electrode and the sustain electrode. For example, when the afterimage prevention voltage Va applied to the address electrode in the sustain period is greater than the scan electrode or the sustain voltage Vs applied to the sustain electrode in the sustain period, the discharge generated in the sustain period may be a scan electrode or It occurs between the sustain electrode and the address electrode. Therefore, sustain discharge cannot be generated efficiently, which causes a huge impact on driving efficiency. Therefore, the afterimage prevention voltage Va has a predetermined voltage value that does not prevent the sustain discharge between the scan electrode and the sustain electrode in the sustain period.

In addition, the bright afterimage prevention voltage Va reduces the voltage difference between the scan electrode or the sustain electrode and the address electrode so that the surface discharge generated between the scan electrode and the sustain electrode in the sustain period is not attracted toward the address electrode.

For example, when the sustain voltage Vs is applied to the scan electrode while the ground level GND voltage is applied to the sustain electrode, sustain discharge is generated by the scan electrode. In the case where the sustain discharge is generated by the scan electrode, a bright afterimage prevention voltage Va is applied to the address electrode. On the contrary, when the sustain voltage Vs is applied to the sustain electrode while the ground level GND voltage is applied to the scan electrode, the sustain discharge is generated by the sustain electrode. In the case where sustain discharge is caused by such a sustain electrode, a bright afterimage prevention voltage Va is applied to the address electrode. In the sustain period, the afterimage prevention voltage Va is applied to the address electrode according to the average image level. The afterimage prevention voltage Va is applied to the address electrode according to the average image level as shown in FIG.

FIG. 10 is a diagram illustrating an example in which a bright afterimage prevention voltage Va is applied to an address electrode according to an average picture level in a sustain period. As shown, the period during which the afterimage prevention voltage Va is applied increases as the average image level decreases. That is, as the power reaches the maximum (peak luminance, minimum average image level, minimum display area), the period during which the afterimage prevention voltage Va is applied to the address electrode in the sustain period increases gradually. In contrast, as the average image level increases, i.e., as the power reaches the lowest (lowest luminance, maximum average image level, maximum display area), the period during which the afterimage prevention voltage Va is applied to the address electrode in the sustain period gradually decreases. . As described above with reference to FIGS. 11A to 11C, the period in which the afterimage prevention voltage Va is applied to the address electrode in the sustain period is changed according to the display area of the plasma display panel, that is, the average image level. .

Referring to FIG. 11A, for example, in the case where the average image level is driven in eight stages, the sustain section is divided into eight stages such as the average image level, and the average image level is the maximum level, that is, each discharge. In the case where the power consumed by the cell is minimum, the period during which the bright afterimage prevention voltage Va is applied to the address electrode in the sustain period is set to zero. That is, the afterimage prevention voltage Va having the voltage value of the ground GND level is applied to the address electrode.

In this case, when the average image level is at the maximum level, the reason for setting the period during which the image persistence prevention voltage Va is applied to the address electrode is set to 0 means that the average image level is at the maximum level. This means that the area 1100a at which an image is displayed on 1100 is maximized. Accordingly, when each discharge cell is discharged at a relatively high power, the power consumption of the entire plasma display panel is rapidly increased. Therefore, when the average image level is maximized, each discharge cell is discharged at a relatively low power level. Limit the power supplied to the discharge cells. As a result, the voltage applied to the scan electrode and the sustain electrode is relatively small, thereby reducing the phenomenon that the discharge in the discharge cell is attracted toward the address electrode. Therefore, in the case where the average image level becomes the maximum level, even if the period during which the bright after-image prevention voltage Va is applied to the address electrode is set to 0, the rate at which the lower phosphor in the discharge cell is discharged is relatively small. The time it takes to return to is shortened, which prevents the creation of an afterimage.

Referring to FIG. 11C, unlike the foregoing description, when the average image level is the lowest level, that is, the power consumed by each discharge cell becomes the maximum, and each discharge cell implements the peak luminance, the image persists in the entire sustain period. The prevention voltage Va is applied to the address electrode. That is, a bright afterimage prevention voltage Va having a voltage value of Va is applied to the address electrode throughout the sustain period.

Here, referring to the reason why the afterimage prevention voltage Va is applied to the address electrode throughout the sustain period, the mean image level is the lowest level, which means that the area 1100c displays an image on the screen 1100 of the plasma display panel. ) Is the minimum. As a result, even when each discharge cell is discharged at a relatively high power, the power consumption of the entire plasma display panel increases relatively little. Therefore, when the average image level is the lowest, each discharge cell is discharged at a relatively high power. The power supplied to each discharge cell is set to discharge. Accordingly, when the average image level is at the lowest level, that is, when the display area of the plasma display panel is minimized, the amount of power consumed by discharging each discharge cell discharged with a relatively large power is reduced, but the plasma is reduced. Increase the brightness of the entire display panel. In this case, when the average image level is the lowest, the voltage applied to the scan electrode and the sustain electrode becomes relatively strong, thereby increasing the phenomenon that the discharge in the discharge cell is attracted toward the address electrode. Therefore, when the average image level becomes the lowest level, the image retention prevention voltage Va is applied to the address electrode throughout the sustain period, thereby reducing the potential difference between the scan electrode and the sustain electrode and the address electrode, thereby generating a difference between the scan electrode and the sustain electrode. The phenomenon of attracting the discharge toward the address electrode is reduced. As a result, the rate at which the lower phosphor in the discharge cell discharges is relatively small, so that the time required for returning to a stable state after discharge is short, thereby preventing the formation of a bright afterimage.

As described above, in addition to the case where the average image level is the lowest or the maximum, the period during which the bright after-image prevention voltage Va is applied to the address electrode in the sustain period can be set differently according to the magnitude of the average image level. Referring to FIG. 11B, when the average image level has a value located between the maximum and the minimum, that is, the area 1100b on which the image is displayed on the screen 1100 of the plasma display panel is the maximum display area 1100a of FIG. 11A. In the case of having a predetermined area smaller than and smaller than the minimum display area 1100c of FIG. 11C, the ratio of the area 1100b on which the image on the screen 1100 of the plasma display panel is displayed to the maximum display area 1100a of FIG. 11A is shown. Alternatively, in response to the ratio of the area 1100b on which the image on the screen 1100 of the plasma display panel is displayed to the minimum display area 1100c of FIG. Decide how long to apply.

As such, when the bright afterimage prevention voltage Va is applied to the address electrode in the sustain period, an application time point for applying the bright afterimage prevention voltage Va may be arbitrarily set within the sustain period. For example, assuming that the total length of the sustain period is 100 mV, and that the afterimage prevention voltage Va is applied to the address electrode for a total of 10 mV in the sustain period, the start point of the sustain period, that is, From the time point of 0 μs in the total period of 100 μs, the afterimage prevention voltage Va may be applied to the address electrode and may be applied to the time of 10 μs of the sustain period. Alternatively, in the sustain section having a total length of 100 mV, the afterimage prevention voltage Va may be applied to the address electrode at a point of 50 mV of the sustain period and may be applied up to 60 mV of the sustain period.

When the content of xenon (Xe) increases in the plasma display panel, the electric field between the scan electrode and the sustain electrode is dispersed by the strong interaction of the address electrode during the surface discharge between the scan electrode and the sustain electrode in the discharge cell. The discharge is further attracted toward the address electrode. However, even if the content of xenon (Xe) in the discharge cell is increased, if the bright-image persistence prevention voltage Va is applied to the address electrode in the sustain period, the voltage difference between the scan electrode or the sustain electrode and the address electrode is reduced, thereby reducing the scan electrode and the sustain in the discharge cell. The surface discharge between the electrodes, i.e., the sustain discharge is reduced in the direction of the address electrode. Accordingly, the degradation of the lower phosphor in the phosphor of the plasma display panel during the sustain discharge in the sustain period is reduced, thereby reducing the time to return to a stable state after the discharge to reduce the occurrence of bright afterimages. In addition, the degradation of the lower phosphor is reduced to improve the life of the plasma display panel.

In the above description, the application of the bright afterimage prevention voltage Va to the sustain period in one subfield according to the average image level is illustrated and described. However, the bright afterimage prevention voltage Va is addressed in the sustain period in one frame. It is also possible to select a subfield to be applied to the electrode and to prevent the generation of the bright afterimage by applying the bright afterimage prevention voltage Va to the address electrode in the sustain period of the selected subfield. Looking at such a method as shown in FIG.

12 is a view showing another driving waveform according to the driving method of the plasma display panel of the present invention. As shown, another driving waveform according to the driving method of the plasma display panel according to the present invention may include at least one frame among the plurality of frames constituting the image, among the subfields included in the frame according to an average picture level. The subfield to which the afterimage prevention voltage Va is applied is selected, and the afterimage prevention voltage Va is applied to the address electrode in the sustain period of the selected subfield.

Here, the number of subfields to which the afterimage prevention voltage Va is applied decreases as the average image level increases, and conversely, as the average image level decreases, the afterimage prevention voltage Va is applied to the address electrode in the sustain period. The number of subfields is increased.

For example, when the average image level is driven in eight stages, subfields included in one frame are divided into eight stages, such as the average image level, and the average image level is the maximum level, that is, respectively. When the power consumed by the discharge cells is minimized, the number of subfields to which the afterimage prevention voltage Va is applied to the address electrode in the sustain period is set to zero. In FIG. 12, only 12 subfields form one frame. However, the number of subfields included in one frame may vary, for example, 8 subfields or 16 subfields may be included in one frame. Is deformable.

As described above, when the average image level is the maximum level, the reason why the number of subfields to which the image persistence prevention voltage Va is applied to the address electrode is set to 0 is the meaning that the average image level is the maximum level. Likewise, this means that the area on which the image is displayed on the screen of the plasma display panel is maximized. Accordingly, when each discharge cell is discharged at a relatively high power, the power consumption of the entire plasma display panel is rapidly increased. Therefore, when the average image level is maximized, each discharge cell is discharged at a relatively low power. Limit the power supplied to the discharge cells. As a result, the voltage applied to the scan electrode and the sustain electrode is relatively small, thereby reducing the phenomenon that the discharge in the discharge cell is attracted toward the address electrode. Therefore, when the average image level reaches the maximum level, since the number of subfields to which the bright image prevention voltage Va is applied to the address electrode is set to 0, the discharge rate of the lower phosphor in the discharge cell becomes relatively small. Later, the time taken to return to a stable state is shortened, thereby preventing the formation of a bright image.

In contrast, when the average image level is at the lowest level, that is, the power consumed by each discharge cell is maximized, and each discharge cell realizes peak luminance, the image persistence is sustained in the sustain period of all subfields included in the frame. The prevention voltage Va is applied to the address electrode. That is, a bright afterimage prevention voltage Va having a voltage value of Va is applied to the address electrode in the sustain period of the mode subfield. The reason why the bright image prevention voltage Va is applied to the address electrode in the sustain period of all the subfields included in one frame is that the average image level becomes the lowest level. This means that the displayed area becomes the minimum. As a result, even when each discharge cell is discharged at a relatively high power, the power consumption of the entire plasma display panel increases relatively little. Therefore, when the average image level is the lowest, each discharge cell is discharged at a relatively high power. The power supplied to each discharge cell is set to discharge. Accordingly, in the case where the average image level is at the lowest level, that is, when the display area of the plasma display panel is minimized, the increase in total power consumed by the plasma display panel by discharging each discharge cell that discharges with relatively large power. While lowering the brightness, the overall brightness of the plasma display panel is increased. In this case, when the average image level is the lowest, the voltage applied to the scan electrode and the sustain electrode becomes relatively strong, thereby increasing the phenomenon that the discharge in the discharge cell is attracted toward the address electrode. Therefore, when the average image level becomes the lowest level, the image retention prevention voltage Va is applied to the address electrode in the sustain period of all subfields, thereby reducing the potential difference between the scan electrode and the sustain electrode and the address electrode, thereby reducing the potential difference. The phenomenon caused by the discharge between the sustain electrode and the sustain electrode is reduced in the direction of the address electrode. As a result, the rate at which the lower phosphor in the discharge cell discharges is relatively small, so that the time required for returning to a stable state after discharge is short, thereby preventing the formation of a bright afterimage.

As described above, in addition to the case where the average image level is the lowest or the maximum, it is natural that the number of subfields to which the bright image prevention voltage Va is applied to the address electrode in the sustain period may be set differently according to the size of the average image level. In addition, the degradation of the lower phosphor is reduced to improve the life of the plasma display panel.

As described above, those skilled in the art will appreciate that the present invention can be implemented in other specific forms without changing the technical spirit or essential features.

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

As described in detail above, the present invention reduces the voltage difference between the scan electrode or the sustain electrode and the address electrode in the sustain period, thereby suppressing the drag of the sustain discharge between the scan electrode and the sustain electrode in the direction of the address electrode. Degradation of the lower phosphor is reduced to reduce the generation of bright afterimages and to improve the lifetime of the plasma display panel.

Claims (6)

A driving method of a plasma display panel which expresses an image composed of a plurality of frames by a combination of at least one subfield in which voltage is applied to an address electrode, a scan electrode, and a sustain electrode in a reset period, an address period, and a sustain period. The period during which the afterimage prevention voltage Va is applied to the address electrode increases as the average picture level decreases in the sustain period of at least one of the plurality of subfields. How to drive the display panel. The method of claim 1, The bright afterimage prevention voltage Va And a voltage value capable of maintaining a sustain discharge between the scan electrode and the sustain electrode in the sustain period. delete The method of claim 1, If the average image level is the highest level And wherein the bright after-image prevention voltage Va having a voltage value of ground (GND) level is applied to the address electrode in the sustain period. The method of claim 1, If the average image level is the lowest level And the bright afterimage prevention voltage Va is applied to the address electrode in the entire sustain period. The method of claim 1, And a time point at which the afterimage prevention voltage Va applied to the address electrode is applied in the sustain period is arbitrarily designated within the sustain period.

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