KR100551058B1 - Driving apparatus of plasma display panel and driving method thereof - Google Patents

Abstract

The present invention relates to a driving apparatus of a plasma display panel for improving low gray scale expressive power and a driving method thereof.

According to the present invention, the load ratio of the input image signal is calculated, and the rise time of the sustain discharge pulse voltage is varied according to the calculated load ratio. Further, the rise time of the sustain discharge pulse voltage is varied according to the weight of the subfield.

In other words, when the load ratio is low, the rise time of the sustain discharge pulse voltage is relatively long, and when the rise time of the sustain discharge pulse voltage is relatively long, when the subfield weight is low, the low gray scale expression power is improved.

PDP, sustain discharge pulse voltage, load factor, APC level

Description

A driving device of a plasma display panel and a driving method thereof {DRIVING APPARATUS OF PLASMA DISPLAY PANEL AND DRIVING METHOD THEREOF}

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

2 shows an electrode arrangement diagram of the plasma display panel.

3 is a diagram illustrating a gray scale display method of a plasma display panel.

4 is a schematic plan view of a plasma display panel according to an embodiment of the present invention.

5 is a schematic block diagram of a controller of a plasma display panel for improving low gray scale expressive power according to an exemplary embodiment of the present invention.

6 is a diagram showing the number of sustain discharge pulses allocated to each subfield according to the APC level.

7 is a diagram illustrating a method of differently adjusting the rising slope of the sustain discharge pulse voltage according to the subfield weight according to the first embodiment of the present invention.

8 is a diagram illustrating a method of differently adjusting the rising slope of the sustain discharge pulse voltage according to the APC level according to the second embodiment of the present invention.

9 is a diagram illustrating an energy recovery circuit for applying a sustain discharge pulse voltage to a scan electrode or a sustain electrode.

10 is a diagram showing the light output according to the rising slope of the sustain discharge pulse.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving apparatus for a plasma display panel (PDP) and a driving method thereof, and more particularly, to a driving apparatus for a plasma display panel for improving low gradation power and a driving method thereof.

Recently, flat display devices such as a liquid crystal display (LCD), a field emission display (FED), and a plasma display panel have been actively developed. Among these flat panel display devices, the plasma display panel has advantages of higher luminance and luminous efficiency and wider viewing angle than other flat panel display devices. Therefore, the plasma display panel is in the spotlight as a display device to replace a conventional cathode ray tube (CRT) in a large display device of 40 inches or more.

A plasma display panel is a flat panel display device that displays characters or images using plasma generated by gas discharge, and tens to millions or more of pixels are arranged in a matrix form according to their size. The plasma display panel is classified into a direct current type and an alternating current type according to a shape of a driving voltage waveform applied and a structure of a discharge cell.

In the DC plasma display panel, the electrode is exposed without the discharge space insulated, so that the current flows in the discharge space while the voltage is applied, and there is a disadvantage in that a resistance for current limitation must be made. On the other hand, in the AC plasma display panel, since the electrode covers the dielectric layer, the current is limited by the formation of a natural capacitance component, and the electrode is protected from the impact of ions during discharge.

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

As shown in FIG. 1, the scan electrode 4 and the sustain electrode 5 covered with the dielectric layer 2 and the protective film 3 on the glass substrate 1 are formed in pairs in parallel. On the glass substrate 6, a plurality of address electrodes 8 covered with the insulator layer 7 are formed. The partition 9 is formed on the insulator layer 7 between the address electrodes 8 in parallel with the address electrode 8, and the phosphor 10 is formed on the surface of the insulator layer 7 and on both sides of the partition 9. Is formed. The glass substrates 1 and 6 are disposed to face each other with the discharge space 11 therebetween so that the scan electrode 4, the address electrode 8, the sustain electrode 5, and the address electrode 8 are orthogonal to each other. The discharge space at the intersection of the scan electrode 4 and the sustain electrode 5 paired with the address electrode 8 forms a discharge cell 12.

2 shows an electrode arrangement diagram of the plasma display panel.

As shown in FIG. 2, the electrodes of the plasma display panel are arranged in a matrix of m × n. Specifically, the address electrodes A1 -Am are arranged in the column direction and n rows of scan electrodes in the row direction ( Y1-Yn and sustain electrodes X1-Xn are arranged in a zigzag. The discharge cell 12 of FIG. 2 corresponds to the discharge cell 12 of FIG.

In general, the driving method of the AC plasma display panel includes a reset period, an addressing period, and a sustain period.

The reset period is a period of initializing the state of each cell in order to perform an addressing operation smoothly on the cell. The addressing period is an address voltage for a cell (addressed cell) turned on to select a cell that is turned on and a cell that is not turned on in a panel. It is a period of time to perform the operation of accumulating wall charge by applying a. The sustain period is a period in which a discharge is applied to actually display an image in the addressed cells by applying a sustain pulse.

As shown in FIG. 3, the plasma display panel divides one frame (1TV field) into a plurality of subfields, and time-division control them to implement gray scale. Each subfield consists of the reset period, the addressing period and the sustain period described above. 3 illustrates a case in which one frame is divided into eight subfields to implement 256 gray levels. Each subfield SF1-SF8 consists of a reset period (not shown), an address period A1-A8, and a sustain period S1-S8, and the sustain periods S1-S8 are light emission periods 1T, 2T. , 4T, ..., 128T) becomes 1: 2: 4: 8: 16: 32: 64: 128.

At this time, for example, in order to implement a gray scale of 3, the discharge cell is discharged in the subfield SF1 having the 1T light emission period and the subfield SF2 having the 2T light emission period so that the sum of the discharge periods is 3T. In this manner, 256 grayscale images are displayed by combining subfields having different light emission periods. Here, although each subfield is divided according to the ratio of the sustain periods, and the gray level is expressed by combining them, in practice, the sustain period of each subfield has a different number of sustain discharge pulses (number of sustain pulses) and the number of sustain discharge pulses. The gradation is expressed by the combination of.

Meanwhile, in order to control the power consumption of the plasma display panel, a method of automatic power control (APC) is generally used. APC is a method of adjusting the total number of sustain discharge pulses of one frame according to the load ratio of the input video signal. When the load ratio of the input video signal is high (that is, in this case, the overall screen is bright, power consumption is consumed). Is consumed a lot to suppress the power consumption by reducing the total number of sustain discharge pulses in one frame, and when the load ratio of the input video signal is low (that is, in this case, it is a dark state as a whole, it does not consume much power). Increase the total number of sustain discharge pulses in one frame. Here, the level of the APC has several stages according to the load ratio of the input video signal, and the number of sustain discharge pulses corresponding to the various stages is predetermined.

Here, when the APC level is low (that is, when the load ratio is low), the total number of sustain discharge pulses of one frame is relatively increased, and accordingly, the number of sustain discharge pulses allocated to each subfield is relatively increased. This also increases the number of sustain discharge pulses allocated to the low-weight subfields used to represent low gradations. As the number of sustain discharge pulses of the low-weight subfield increases, the emission luminance of the low-weight subfield increases, so that an error-diffused dot (DOT) diffused around to express low gray levels is well identified. A problem arises. On the other hand, according to the trend of the current PDP to increase the luminous efficiency through high Xe, etc., the luminous luminance per sustain discharge pulse increases, so that it is more visually discriminated and there is a problem in low gradation power.

That is, in order to express the gray scale of the plasma display panel, in order to express the gray scale below the decimal point, an error diffusion method that generally spreads an error around is mainly used. However, since the luminous efficiency increases, the luminous luminance per sustain discharge pulse increases. In this case, the error-diffused dots DOT are better identified, which causes many problems in low gradation representation. In particular, when the number of sustain discharge pulses allocated to the low-weight subfield due to the low APC level increases, the emission luminance of the low-weight subfield increases, so that an error-diffused dot (DOT) is visually better identified. The gradation expression becomes worse.

SUMMARY OF THE INVENTION The present invention has been made in an effort to solve the above-described problems of the related art, and to provide a driving apparatus for a plasma display panel and a method of driving the same which improve low gray level expression even when the APC level is low and the luminous efficiency is high. It is for.

A driving method of a plasma display panel according to a feature of the present invention for achieving the above object is

A driving method of a plasma display panel in which a discharge space is formed by a plurality of first electrodes and a second electrode,

(a) measuring a load ratio of an input image signal input to the plasma display panel;

(b) applying a voltage rising from a first voltage to a second voltage to the first electrode such that a sustain discharge pulse voltage is applied between the first and second electrodes in a sustain period;

The period in which the first electrode rises from the first voltage to the second voltage varies according to the load ratio of the measured input image signal. Here, the period in which the first electrode rises from the first voltage to the second voltage is longer when the load ratio measured in step (a) is lower than when the load ratio is high.

The driving method of the plasma display panel according to another aspect of the present invention

A driving method of a plasma display panel in which a discharge space is formed by a plurality of first electrodes and a second electrode,

(a) When the load ratio of the image signal input to the plasma display panel is a first load ratio, a first discharge voltage is applied to the first electrode at a first voltage so that a sustain discharge pulse voltage is applied between the first and second electrodes in a sustain period. Applying a rising voltage for a first period of time up to two voltages;

(b) when the load ratio of the input image signal is a second load ratio lower than the first load ratio, a sustain discharge pulse voltage is applied between the first and second electrodes in a sustain period at a first voltage; And applying a rising voltage to a second voltage for a second period longer than the first period. Here, the first period and the second period may vary according to the subfield weights.

A driving device of the plasma display panel according to another aspect of the present invention

Driving a plasma display panel for dividing an image of each field displayed on the plasma display panel in response to an input video signal into a plurality of subfields, and displaying a gray level according to the combination of the subfields to display an image corresponding to the video signal. In the apparatus,

An automatic power controller which measures a load ratio corresponding to one frame data of the input video signal;

A scanning / maintenance drive control section which generates a control signal for changing the rise time of the sustain discharge pulse voltage in accordance with the load ratio measured by the automatic power control section; And

And a scan / hold driver for driving the plasma display panel in response to a control signal generated by the scan / hold drive control unit. Here, the rise time of the sustain discharge pulse voltage is required to increase the voltage of the sustain electrode or the scan electrode from the first voltage to the second voltage to apply the sustain discharge pulse voltage between the sustain electrode and the scan electrode in the sustain period. It is characterized by the time. The scanning / sustaining driving control section generates a control signal for changing the rising time of the sustain discharge pulse in accordance with the weight of the subfield.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention. Like parts are designated by like reference numerals throughout the specification.

Now, a driving apparatus and a driving method of the plasma display panel according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 4 to 10.

4 is a schematic plan view of a plasma display panel according to an embodiment of the present invention.

As shown in FIG. 4, the plasma display panel according to the exemplary embodiment of the present invention includes a plasma panel 100, an address driver 200, a scan / sustain driver 300, and a controller 400. Here, the address driving unit 200, the scan / maintenance driving unit 300, and the control unit 400 except the plasma panel 100 are included to form a driving device of the plasma display panel.

The plasma panel 100 includes a plurality of address electrodes A1-Am arranged in the column direction, and a plurality of scan electrodes Y1-Yn and sustain electrodes X1-Xn arranged in a zigzag pattern in the row direction. . The address driver 200 receives an address drive control signal from the controller 400 and applies a display data signal for selecting a discharge cell to be displayed to each address electrode A1-Am. The scan and sustain driver 300 receives a control signal from the controller 400 and alternately inputs a sustain discharge pulse voltage Vs to the scan electrodes Y1-Yn and the sustain electrodes X1-Xn to the discharge cells selected. Perform sustain discharge. In the scan and sustain driver 300 according to an exemplary embodiment of the present invention, when the sustain discharge pulse voltage Vs is applied by using an energy recovery circuit, the slope of applying the sustain discharge pulse voltage Vs to each subfield and the APC level is determined. By applying differently according to the control of the light generated in the sustain discharge. A specific method of adjusting the amount of sustain discharge light according to each subfield weight and APC level is to adjust the amount of light by adjusting the turn-on time of the switch used to raise the sustain discharge pulse voltage (Vs) in the energy recovery circuit as described below. I can regulate it.

The controller 400 receives R, G, and B image signals and a synchronization signal from the outside, divides one frame into several subfields, and divides each subfield into a reset period, an address period, and a sustain period (sustain period). Drive the panel. At this time, the controller 400 adjusts the number of sustain discharge pulses in each sustain period of the subfield in one frame and supplies the necessary control signals to the address driver 200 and the scan / sustain driver 300. The control unit 400 according to an embodiment of the present invention obtains the APC level of the input image signal, and then controls the rising slope to apply the sustain discharge pulse voltage Vs according to the APC level and the weight of each subfield. Create This control signal is transmitted to the scan / sustain driver 300.

5 is a schematic block diagram of a controller of a plasma display panel for improving low gray scale expressive power according to an exemplary embodiment of the present invention.

As shown in FIG. 5, the control unit 400 of the plasma display panel according to the embodiment of the present invention includes an inverse gamma correction unit 410, an error diffusion unit 420, a memory control unit 430, and automatic power control. Control, 'APC') unit 440, and scanning / maintenance driving control unit 450.

The inverse gamma correction unit 410 maps n-bit R, G, and B image input data, which is currently input image data, to an inverse gamma curve and corrects the m-bit (m≥n) image signal. In a typical plasma display panel, n is 8 and m is 10 or 12.

In this case, the image signal input to the inverse gamma correction unit 410 is a digital signal. When an analog image signal is input to the plasma display panel, the analog image signal may be converted into a digital image signal by an analog-to-digital converter (not shown). There is a need. The inverse gamma correction unit 410 may be a logic circuit for generating a lookup table (not shown) or data corresponding to an inverse gamma curve that stores data corresponding to an inverse gamma curve for mapping an image signal. (Not shown).

The error diffusion unit 420 is inversely gamma corrected by the inverse gamma correction unit 410 and error-diffuses the lower m-n bit image of the extended bit m image to surrounding pixels. Error diffusion is a method of displaying an image of a lower bit by separating an image of a lower bit to be diffused into adjacent pixels and a detailed description thereof is described in Korean Patent Laid-Open Publication No. 2002-0014766.

The memory controller 430 generates subfield data corresponding to the gray level of the image signal output from the error diffusion unit 420 and rearranges the subfield data into address data for driving the plasma display panel. In this case, the memory controller 430 separates all subfields of one frame for each subfield, stores them in a frame memory (not shown in FIG. 5) for each subfield, and stores address data for all pixels for each subfield. The memory is read from the memory and transmitted to the address driver 200.

The APC unit 440 detects the load rate using the image data output from the inverse gamma correction unit 420, calculates the APC level according to the detected load rate, and maintains the number of sustain pulses corresponding to the calculated APC level (maintenance discharge pulse). Number) and output. That is, the APC unit 440 calculates the total number of sustain pulses for each frame according to the APC level, and calculates the number of sustain pulses of each subfield corresponding thereto. The APC unit 440 calculates an average signal level (ASL) for each frame to determine the number of sustain pulses, which is calculated by Equation 1 below.

In Equation 2, R _{x, y} , G _{x, y} , B _{x, y} represent R, G, B grayscale values at x, y positions, respectively, and N and M represent horizontal and vertical sizes of the frame, respectively. . The APC unit 440 determines the APC level in consideration of the brightness and power consumption by the average signal level ASL calculated as in Equation 1, and sustain pulses for each frame of the input video signal corresponding to the determined APC level. The number (number of sustain discharge pulses) is determined differently. When the average signal level calculated in Equation 1 is low, that is, when the APC level is low (load rate is low), the APC unit 440 increases the number of sustain pulses, and the average signal level is high. In this case (that is, when the APC level is high), a lot of power consumption is consumed, thereby increasing the number of sustain pulses (number of sustain discharge pulses). In the embodiment of the present invention, the APC level is determined through the average signal level (ASL), but the present invention is not limited thereto, and other methods such as determining the APC level through on / off information of each subfield data may be performed. Can be applied. In addition, in the embodiment of the present invention, the APC unit 440 determines the APC level using the data output from the inverse gamma correction unit 410, but the present invention is not limited thereto, but the error diffusion unit 420 spreads the error. The APC level may be calculated using other data, such as determining the APC level using the collected data.

6 is a diagram showing the number of sustain discharge pulses allocated to each subfield according to the APC level.

As shown in FIG. 6, when the APC level is increased, the number of sustain discharge pulses allocated to one frame is gradually reduced, and accordingly, the number of sustain discharge pulses allocated to each subfield is also reduced. As such, the APC unit 440 controls the power consumption by adjusting the number of sustain discharge pulses according to the APC level.

The scan and sustain drive control unit 450 generates a control signal corresponding to the number of sustain discharge pulses (the number of sustain pulses) output from the APC unit 440 and outputs the control signal to the sustain and scan drive unit 300. At this time, the scan / maintenance drive control unit 450 according to the embodiment of the present invention adjusts the slope upon application of the sustain discharge pulse voltage Vs according to the APC level (that is, the load factor) calculated in the APC 440. Generate a control signal. When the APC level (i.e., the load factor) is low, a problem occurs in the expression of low gradation, so the rising slope of the sustain discharge pulse voltage is smoothed to reduce the unit light quantity, and when the APC level (i.e., the load factor) is high, Since no problem occurs, the rising slope of the sustain discharge pulse voltage is relatively urgent. On the other hand, with respect to the determined APC level, the problem of low gradation can be solved by adjusting the unit light amount by changing the rising slope of the sustain discharge pulse voltage for each weight of the subfield.

As such, the scan / sustain driving controller 450 generates a control signal and transmits the control signal to the sustain / scan driver 300 according to the APC level and the subfield weight so as to apply a rising slope of the sustain discharge pulse voltage differently. See below.

First, a method of adjusting the rising slope of the sustain discharge pulse voltage according to the subfield weight at the determined APC level according to the first embodiment of the present invention will be described with reference to FIG. 7.

7 is a diagram illustrating a method of differently adjusting the rising slope of the sustain discharge pulse voltage according to the subfield weight according to the first embodiment of the present invention. FIG. 7 is a diagram illustrating a change in the number of sustain discharge pulses applied in each subfield and a rising slope of the sustain discharge pulse voltage in each subfield when the APC level is 0 (zero) as an example.

As indicated by the arrows in FIG. 7, when the APC level is 0 (zer), the rising slope of the sustain discharge pulse voltage of the subfield SF1 having the minimum weight and the subfields SF2 to SF7 having the low weight adjacent thereto is different. The luminance of the unit light is reduced by making it relatively gentler than the rising slope of the sustain discharge pulse voltages of the subfields SF8 to SF11. The low-weight subfields are mainly used to express low gray levels, and when the luminance of the unit light is increased due to increased luminous efficiency, a problem occurs in the low-gray level expression power. Thus, the low-weight subfields SF1 to SF7 are maintained as described above. The unit light is reduced by smoothing the rising slope of the discharge pulse voltage. Here, the reference for the subfield having a small weight is preferably set to the case where the weight is less than or equal to 1/10 of the sum of the total weights. In this case, when a weight of each subfield shown in FIG. 7 and a weight of another subfield are set, the subfield which makes the rising slope of the sustain discharge pulse voltage relatively gentle may be changed somewhat. In addition, although FIG. 7 illustrates only the case where the APC level is 0, the same may be applied to the other levels. However, since the number of sustain discharge pulses allocated to each subfield is relatively high when the APC level is low, the rising slope of the sustain discharge pulse voltage in the low weight subfield is relatively gentle at this time as in the first embodiment of the present invention. As a result, the amount of unit light can be further reduced to further improve the problem of low gradation power.

Next, a method of adjusting the rising slope of the sustain discharge pulse voltage according to the APC level according to the second embodiment of the present invention will be described with reference to FIG. 8.

8 is a diagram illustrating a method of differently adjusting the rising slope of the sustain discharge pulse voltage according to the APC level according to the second embodiment of the present invention.

As shown in Fig. 8, the rising slope of the sustain discharge pulse voltage is adjusted differently in the direction of the arrow, that is, according to the APC level. When the APC level is low, that is, when the screen load rate is low, the number of sustain discharge pulses is relatively high. When the APC level is low, that is, when the screen load rate is high, the number of sustain discharge pulses is relatively small. Therefore, when the APC level is low (that is, when the number of sustain discharge pulses is large), the rising slope of the sustain discharge pulse voltage is relatively gentle to reduce the unit light quantity, thereby improving low gray scale expressive power. The rising slope of the sustain discharge pulse voltage is made relatively rapid. As described above, since the number of sustain discharge pulses allocated when the APC level is low (that is, when the load ratio is low) increases due to the increase in the amount of light, a problem occurs in low gradation expression power. Thus, as in the second embodiment of the present invention, the APC When the level is low, the low gradient expression power can be improved by decreasing the unit light amount by making the rising slope of the sustain discharge pulse voltage relatively gentle.

In the first embodiment, the rising slope of the sustain discharge pulse voltage is set differently according to the weight of the subfield. In the second embodiment, the rising slope of the sustain discharge pulse voltage is set differently according to the APC level. By combining the embodiment and the second embodiment, the rising slope of the sustain discharge pulse voltage may be set differently according to the subfield weight and the rising slope of the sustain discharge pulse voltage to further improve the low gray scale expression power. That is, as in the second embodiment, when the APC level is low, the rising slope of the sustain discharge pulse voltage is relatively gentle, and as in the first embodiment, the rising slope of the sustain discharge pulse voltage of the low-weight subfield has a high weight. By making it gentler than the rising slope of the sustain discharge pulse voltage of the subfield, the amount of light can be relatively reduced to further improve the low gradation power.

Hereinafter, a method of adjusting the rising slope of the sustain discharge pulse voltage will be described with reference to FIGS. 9 and 10.

FIG. 9 is a diagram showing an energy recovery circuit for applying the sustain discharge pulse voltage Vs to the scan electrode or the sustain electrode, and FIG. 10 is a diagram showing the light output according to the rising slope of the sustain discharge pulse. The energy recovery circuit shown in Fig. 9 is an L.F. Circuits proposed by Weber (US Pat. Nos. 4,866,349 and 5,081,400). A detailed description of the circuit shown in FIG. 9 is described in detail in US Pat. Nos. 4,866,349 and 5,081,400.

The switch S1 is turned on to apply the sustain discharge pulse voltage Vs to the sustain electrode or the scan electrode (the first terminal or the second terminal of the panel capacitor Cp shown in FIG. 9 corresponding thereto). Then, a resonance path is formed by the capacitor Cr, the inductor L, and the panel capacitor Cp so that the voltage at the first terminal of the panel capacitor Cp (which corresponds to the sustain electrode or the scan electrode) rises to near the Vs voltage. do. The S2 switch is turned on while the first terminal of the panel capacitor Cp rises to near the Vs voltage to clamp the voltage of the first terminal of the panel capacitor Cp to the Vs voltage. In this way, the sustain discharge pulse voltage Vs is applied to the sustain electrode or the scan electrode.

At this time, as shown in (a) and (b) of FIG. 10, the light output varies depending on the time t1, t2 taken to turn on the switch S2 after the switch S1 is turned on. That is, as shown in FIG. 10A, when the switch S3 is turned on for a relatively short time t1 after the switch S1 is turned on, the sustain discharge pulse is rapidly clamped to the Vs voltage within a short time. As shown in (b) of FIG. 10, when the switch S3 is turned on for a relatively long time t2 after turning on the switch S1 as shown in FIG. The rising portion becomes relatively long and the light output is relatively weak. At this time, as can be seen from (a) and (b) of Figure 10 it can be seen that the rising slope of the sustain discharge pulse is different from each other. In the above-described embodiment of the present invention, a method of changing the rising slope of the sustain discharge pulse voltage is possible by adjusting the turn-on times of the switches S1 and S2 as shown in FIGS. 9 and 10.

5, the scan / maintenance drive controller 450 generates a control signal for the switch timing as described above in order to adjust the rising slope of the sustain discharge pulse voltage differently. To transmit.

The scan / maintenance driver 300 includes an energy recovery circuit as shown in FIG. 9, and receives the switch control signal according to the APC level and the subfield weight from the scan / maintenance drive controller 450. The sustain discharge pulse voltage Vs is applied to Y1-Yn and sustain electrodes X1-Xn.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

As described above, according to the present invention, the low gray scale expression power is further improved by varying the application time (tilt) of the sustain discharge pulse voltage according to the load ratio (APC level) and the magnitude of the subfield weight.

Claims (13)

A method of driving a plasma display panel in which a discharge space is formed by a plurality of first electrodes and a second electrode, (a) measuring a load ratio of an input image signal input to the plasma display panel; (b) applying a voltage rising from a first voltage to a second voltage to the first electrode such that a sustain discharge pulse voltage is applied between the first and second electrodes in a sustain period; And a period in which the first electrode rises from the first voltage to the second voltage is changed according to the measured load ratio of the input image signal and is changed according to the weight of the subfield. The method of claim 1, And a period in which the first electrode rises from the first voltage to the second voltage is longer when the load ratio measured in step (a) is lower than when the load ratio is high. delete The method of claim 1, And a period in which the first electrode rises from the first voltage to the second voltage is longer than when the subfield weight is high. The method according to claim 1 or 2, The variation of the period during which the first electrode rises from the first voltage to the second voltage is determined by a timing of a switch of an energy recovery circuit electrically connected to the first electrode or the second electrode. Method of driving. A method of driving a plasma display panel in which a discharge space is formed by a plurality of first electrodes and a second electrode, (a) When the load ratio of the image signal input to the plasma display panel is a first load ratio, a first discharge voltage is applied to the first electrode so that a sustain discharge pulse voltage is applied between the first and second electrodes in a sustain period. Applying a rising voltage for a first period of time up to two voltages; (b) when the load ratio of the input image signal is a second load ratio lower than the first load ratio, the first voltage is applied to the first electrode such that a sustain discharge pulse voltage is applied between the first and second electrodes in a sustain period. Applying a rising voltage to the second voltage for a second period longer than the first period, at And the first period and the second period vary in accordance with subfield weights. delete The method of claim 6, And the first period and the second period are longer when the subfield weight is larger than when the subfield weight is large. Driving a plasma display panel for dividing an image of each field displayed on the plasma display panel in response to an input video signal into a plurality of subfields, and displaying a gray level according to the combination of the subfields to display an image corresponding to the video signal. In the apparatus, An automatic power controller which measures a load ratio corresponding to one frame data of the input video signal; A scanning / maintenance driving control section which generates a control signal for varying the rise time of the sustain discharge pulse voltage according to the load ratio and the weight of the subfield measured by the automatic power control section; And And a scan / hold driver for driving the plasma display panel in response to a control signal generated by the scan / hold drive control unit. The method of claim 9, The rise time of the sustain discharge pulse voltage is a time taken to raise the voltage of the sustain electrode or the scan electrode from the first voltage to the second voltage to apply the sustain discharge pulse voltage between the sustain electrode and the scan electrode in the sustain period. A drive device of a plasma display panel. delete The method of claim 9 or 10, And the holding and scanning driving control section generates a control signal for extending the rising time of the sustain discharge pulse when the load ratio is lower than that when the load ratio is large. The method of claim 9, And the scanning / maintenance driving control section generates a control signal for extending the rising time of the sustain discharge pulse when the subfield weight is lower than that when the subfield weight is high.

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