KR100531484B1 - Method and Apparatus for Driving Plasma Display Panel - Google Patents

Abstract

The present invention relates to a method and apparatus for driving a plasma display panel capable of reducing the number of subfields while preventing contour noise and increasing gradation expression power.

The plasma display panel driving method includes inverse gamma correction of input video data; A carry signal is generated by adding lower bits of some of the inverse gamma corrected video data and error diffusion coefficients calculated by giving different weights to data of adjacent pixels to generate a carry signal, and apply the carry signal to the remaining upper bits of the video data. An error diffusion step of adding and error diffusion; The error-diffused video data is included in a subfield pattern arranged in the order of first to fourth selective write subfields, fifth and sixth selective erase subfields, seventh selective write subfields, and eighth selective erase subfields. Mapping to display on the plasma display panel.

Description

Method and apparatus for driving plasma display panel {Method and Apparatus for Driving Plasma Display Panel}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving apparatus for a plasma display panel, and more particularly, to a method and apparatus for driving a plasma display panel capable of reducing contour noise and improving gray scale expression.

Recently, a plasma display panel (PDP), which is easy to manufacture a large panel, has attracted attention as a flat panel display device. The PDP displays an image by adjusting the gas discharge period of each of the pixels according to the digital video data. As such a PDP, a PDP having three electrodes as shown in FIG. 1 and driven by an AC voltage is representative.

The discharge cell of the AC PDP shown in FIG. 1 includes sustain electrode pairs 12A and 12B formed on the upper substrate 10 and data electrodes 20 formed on the lower substrate 18.

Each of the sustain electrode pairs 12A and 12B has a double layer structure of a transparent electrode and a metal electrode. The sustain electrode pairs 12A and 12B have a scan electrode 12A supplied with a scan signal for address discharge and a sustain signal for sustain discharge, and a sustain electrode supplied with a sustain signal alternately with the scan electrode 12A. Separated by 12B. The data electrode 20 is formed to intersect with the sustain electrode pairs 12A and 12B to supply a data signal for address discharge.

An upper dielectric layer 14 and a passivation layer 16 are stacked on the upper substrate 10 on which the sustain electrode pairs 12A and 12B are formed, and a lower dielectric layer 22 is formed on the lower substrate 18 on which the data electrode 20 is formed. do. The upper dielectric layer 14 and the lower dielectric layer 22 accumulate charges generated by the discharge. The protective film 16 prevents damage to the upper dielectric layer 14 due to sputtering of plasma particles during discharge and increases the emission efficiency of secondary electrons. The dielectric layers 14 and 22 and the protective layer 16 may lower the driving voltage applied from the outside.

A partition wall 24 is formed on the lower substrate 18 on which the lower dielectric layer 22 is formed, and a phosphor layer 26 is formed on the lower dielectric layer 22 and the surfaces of the partition wall 24. The partition wall 24 separates the discharge space to prevent the ultraviolet rays generated by the gas discharge from leaking into the adjacent discharge space. The phosphor layer 26 emits light by ultraviolet rays generated by gas discharge to generate red (R), green (G), or blue (B) visible light. The discharge space is filled with an inert gas for gas discharge.

This discharge cell is selected by address discharge by the data electrode 20 and the scan electrode 12A, and the selected discharge cell maintains the discharge by sustain discharge by the sustain electrode pairs 12A and 12B. The discharge cell emits the fluorescent material 26 with ultraviolet rays generated during the sustain discharge to emit visible light of red (R), green (G), and blue (B). In this case, the discharge cell adjusts the sustain discharge period, that is, the number of sustain discharges according to the video data, thereby implementing gray scale for displaying an image. A color of one pixel is realized by a combination of three discharge cells coated with red (R), green (G), and blue (B) phosphors 26, respectively.

As a method of driving such a PDP, an ADS (Address and Display Separation) driving method that is driven by being divided into an address period and a display period, that is, a sustain period is typical. As shown in FIG. 2, the ADS driving method divides one frame 1F into a plurality of subfields SF1 to SF8 corresponding to each bit of video data. Each of the subfields SF1 to SF8 again has a reset period RPD for initializing a radiation cell, an address period APD for selecting a discharge cell, and a sustain period SPD for maintaining the discharge of the selected discharge cell. Is divided into Here, the PDP implements the corresponding gradation by assigning different weights to the subfields SF1 to SF8 in the sustain period SPD and combining the sustain period SPD according to the video data.

Such a driving method of a PDP is roughly classified into a selective writing (SW) method and a selective erasing (SE) method according to whether or not the discharge cells are selected by the address discharge.

The SW method turns off the full screen in the reset period and then turns on the selected discharge cells in the address period. In the sustain period, an image is displayed by maintaining the discharge of the discharge cells selected by the address discharge.

In such a SW method, the width of the scan pulse is set relatively wide (for example, 3 mW) so that sufficient wall charges are formed in the discharge cell. However, when the width of the scan pulse is set wide, the address period is set long, and the sustain period which contributes to the luminance is set relatively short.

The SE method turns off the selected discharge cells in the address period after turning on the full screen by writing and discharging the full screen in the reset period. Subsequently, in the sustain period, images are displayed by sustaining discharge only those discharge cells not selected by the address discharge.

In this SE method, the width of the scan pulse is set to be relatively narrow (for example, 1 ms) to cause erase discharge in the discharge cell. As a result, the address period can be set short, and a relatively long time can be allocated to the sustain period which contributes to the luminance. However, the SE method has a disadvantage of low contrast because the full screen is turned on in the reset period, which is a non-display period.

In addition, the PDP generates a gray level using a combination of subfields, so that a contour noise is generated in a video, thereby degrading display quality. For example, when the left half of the screen is displayed with a gradation value of 128 and the right half of the screen is displayed with a gradation value of 127, when the screen is moved to the left side, a white band appears at the boundary between the gradation values 128 and 127. On the contrary, when the left half of the screen is displayed with a gradation value of 128 and the right half of the screen is displayed with a gradation value of 127, a black band appears at the boundary between the gradation values 127 and 128 when the screen is moved to the right.

As a method of removing such contour noise, one subfield is divided to add one or two subfields, a rearranged order of subfields, a subfield added, and a rearranged order of subfields. And error diffusion methods have been proposed. In the case of using the method of adding subfields among them, the sustain period becomes insufficient or the sustain period cannot be allocated in the SW method.

For example, in the SW method, when two subfields of eight subfields are divided so that one frame includes ten subfields, the sustain period is absolutely insufficient as follows. When one frame includes ten subfields, the address period is 14.4 ms calculated as 3 ms (pulse width of scan pulse) x 480 lines (VGA class) x 10 (number of subfields) per frame. In contrast, the sustain period is obtained by subtracting an address period of 14.4 ms per frame, one reset period of 0.3 ms, an erase period of 100 ms x 10 (number of subfields), and a 1 ms vertical sync signal (Vsync) margin period (16.67). ms-14.4ms-0.3ms-1ms-1ms) The remaining period is -0.03ms. As described above, in the SW method, if a frame is composed of eight subfields, a sustain period of about 3ms can be secured. However, if a frame is composed of ten subfields, it is impossible to secure a sustain period. In order to solve this problem, there is a driving method in which a single screen is divided and dual-scanned. However, in this case, since driving drive ICs have to be added as much as that, there is another problem of increasing manufacturing cost.

In order to solve the problems of each of the conventional SW method or SE method, the applicant of the present application is the Korean Patent Application No. 2000-12669, 2000-53214, 2001-3003, 2001-6492, etc. Through the arrangement of a plurality of SW subfields and a plurality of SE subfields within one frame period, a method for satisfying both high-speed driving and high contrast (hereinafter referred to as SWSE method) has been proposed.

Figure 3 shows the configuration of one frame according to the SWSE method proposed in the Republic of Korea Patent Application No. 2001-6492.

In FIG. 3, one frame is divided into 12 subfields, that is, six subfields SF1 to SF6 of the SW method and six subfields SF7 to SF12 of the SE method. The first subfield SF1 is divided into a reset period for turning off the full screen, a SW address period for turning on the selected discharge cells, a sustain period for sustaining discharge discharge for the discharge cell selected by the address discharge, and an erasing period for erasing the sustain discharge. Each of the second to fifth subfields SF2 to SF5 is divided into a SW address period, a sustain period, and an erase period. The sixth subfield SF6 is divided into a SW address period and a sustain period. In the first to sixth subfields SF1 to SF6, the SW address period and the erase period are the same for each subfield, while the sustain period is 2 ⁿ (n = 0, 1, 2, 3, 4) in each subfield. Is increased by 5). The seventh to twelfth subfields SF7 to SF12 have an SE address period for turning off the selected discharge cells without a full surface writing period in which the full screen is lit, and a sustain period for sustaining discharge cells other than the discharge cells selected by the address discharge. Divided into. In the seventh to twelfth subfields SF7 to SF12, not only the SE address period but also the sustain period are set equally. The sustain period of the seventh to twelfth subfields SF7 to SF6 is set to a luminance relative ratio of 2 ⁵ to have the same luminance relative ratio as that of the sixth subfield SF6.

Table 1 below shows gray levels and coding methods expressed in the first to twelfth subfields SF1 to F12.

Gradation SF1 (1) SF2 (2) SF3 (4) SF4 (8) SF5 (16) SF6 (32) SF7 (32) SF8 (32) SF9 (32) SF10 (32) SF11 (32) SF12 (32) 0 to 31 Binary coding × × × × × × × 32-63 Binary coding ○ × × × × × × 64 to 95 Binary coding ○ ○ × × × × × 96-127 Binary coding ○ ○ ○ × × × × 128-159 Binary coding ○ ○ ○ ○ × × × 160-191 Binary coding ○ ○ ○ ○ ○ × × 192-223 Binary coding ○ ○ ○ ○ ○ ○ × 224-255 Binary coding ○ ○ ○ ○ ○ ○ ○

As can be seen from Table 1, the first to fifth subfields SF1 to SF5 disposed in front of the frame among the first to twelfth subfields SF1 to SF12 are binary coded. The sixth to twelfth subfields SF6 to SF12 are linearly coded. That is, each of the seventh to twelfth subfields SF7 to SF12 driven by the SE method must turn on the previous subfield so that unnecessary discharge cells can be turned off whenever the subfields are consecutive. For example, in order for the seventh subfield SF7 to be turned on, the sixth subfield SF6 driven by the previous subfield SW method should be turned on. After the sixth subfield SF6 is turned on, the unnecessary discharge cells are turned off in the seventh to twelfth subfields SF7 to SF12. For this purpose, in order for the SE subfield ESF to be used, the cells turned on in the sixth subfield WSF, which is the last SW subfield WSF, must be turned on by the sustain discharge. Therefore, the seventh subfield SF7 does not need a separate writing discharge for the SE address. In addition, the eighth to twelfth subfields SF8 to SF12 also selectively turn off cells that are turned on in the previous subfield without front lighting. For example, if the gray scale value 74 is displayed, the second and fourth subfields SF2 and SF4 of the first to fifth subfields SF1 to SF5 are turned on by the binary coding, and the sixth and fifth subfields are turned on. 7 Subfields SF6 and SF7 are turned on in succession.

When driving a PDP of VGA level (480 scan lines) using the SWSE method, a total of about 11.52 ms is required for the address period, so that a total of 3.35 ms can be allocated for the sustain period. However, when the HD class PDP of 720 scan lines or more is driven by the SWSE method, an address period is increased and a sustain period is insufficient. Accordingly, there is a demand for a method capable of driving a PDP or higher in HD class or higher by reducing the number of subfields while reducing contour noise by adopting the SWSE method. In addition, there is a need for a method of increasing the gray scale expression power reduced as the number of subfields decreases without increasing the number of subfields.

Accordingly, it is an object of the present invention to provide a PDP driving method and apparatus capable of reducing the number of subfields while reducing contour noise.

Another object of the present invention is to provide a PDP driving method and apparatus capable of increasing gray scale expression power without increasing a subfield.

In order to achieve the above object, the PDP driving method according to the present invention comprises a method of driving a PDP with a combination of selective write subfields and selective erase subfields, comprising: performing inverse gamma correction on input video data; A carry signal is generated by adding lower bits of some of the inverse gamma corrected video data and error diffusion coefficients calculated by giving different weights to data of adjacent pixels to generate a carry signal, and apply the carry signal to the remaining upper bits of the video data. An error diffusion step of adding and error diffusion; The error-diffused video data is included in a subfield pattern arranged in the order of first to fourth selective write subfields, fifth and sixth selective erase subfields, seventh selective write subfields, and eighth selective erase subfields. Mapping to display on the PDP. The luminance weights of the first to fourth selective write subfields and the seventh selective write subfield are set to increase sequentially. The fifth and sixth selective erase subfields are set to have the same luminance weight as the fourth selective write subfield, and the eighth selective erase subfield is set to have the same luminance weight as the seventh selective write subfield. The first to fourth selective write subfields and the seventh selective write subfield comprise a reset period for initializing cells of a full screen; An address period for turning on selected cells; And a sustain period for maintaining the discharges of the cells selected in the address period according to the luminance weight. The first to third selective write subfields further include an erase period for erasing all discharges after the sustain period. The fifth and sixth selective erase subfields and the eighth selective erase subfields each of which comprises: an address period for turning off selected cells among cells which remain on from a previous subfield; And a sustain period for causing discharges of cells that remain in the on state other than the selected cell according to the luminance weight. According to an aspect of the present invention, there is provided a method of driving a PDP using a combination of selective write subfields and selective erase subfields, the method comprising: performing inverse gamma correction on input video data; The lower bit of the reverse gamma corrected video data is used to select the corresponding gray level among the dither mask patterns and the dither value of the corresponding position in the dither mask pattern of the frame, and the upper bit of the remaining part of the video data. Dithering the dither by adding the selected dither value to each field; The error-diffused video data is included in a subfield pattern arranged in the order of first to fourth selective write subfields, fifth and sixth selective erase subfields, seventh selective write subfields, and eighth selective erase subfields. Mapping to display on the PDP. According to an aspect of the present invention, there is provided a PDP driving apparatus comprising: a gamma correction unit configured to inverse gamma correct an input video data; A carry signal is generated by adding lower bits of some of the inverse gamma corrected video data and error diffusion coefficients calculated by giving different weights to data of adjacent pixels, and generating the carry signal by applying the generated carry signal to the rest of the video data. An error diffusion unit for adding and outputting bits; The error-diffused video data is included in a subfield pattern arranged in the order of first to fourth selective write subfields, fifth and sixth selective erase subfields, seventh selective write subfields, and eighth selective erase subfields. A subfield mapping unit for mapping and outputting; And a data driver driving the plasma display panel according to the video data output from the subfield mapping unit. According to an aspect of the present invention, there is provided a PDP driving apparatus comprising: a gamma correction unit configured to inverse gamma correct an input video data; The lower bit of the reverse gamma corrected video data is used to select the corresponding gray level among the dither mask patterns and the dither value of the corresponding position in the dither mask pattern of the frame, and the upper bit of the remaining part of the video data. A dithering unit which adds and outputs the selected dither value; The dithered video data is mapped to subfield patterns arranged in the order of first to fourth selective write subfields, fifth and sixth selective erase subfields, seventh selective write subfields, and eighth selective erase subfields. A subfield mapping unit to output the result; And a data driver driving the plasma display panel according to the video data output from the subfield mapping unit.

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Other objects and features of the present invention in addition to the above objects will become apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail.

4 illustrates a frame configuration of a PDP driving method according to an embodiment of the present invention.

In FIG. 4, one frame of the PDP according to the present invention is divided into eight subfields, that is, five SW subfields SF1 through SF4 and SF7 and three SE subfields SF5, SF6 and SF8. .

The first to third subfields SF1 to SF3 of the SW subfields are reset periods for uniformly forming a predetermined amount of wall charges in the cells of the full screen and select on-cells as write discharges. A SW address period, a sustain period for causing sustain discharge for the selected on-cell, and an erase period for erasing wall charges in the cell after the sustain discharge. The fourth and seventh subfields SF4 and SF7 disposed before the SE subfield among the SW subfields, unlike the SW subfields, include a reset period, a SW address period, and a sustain period except for an erase period. do. In the SW subfields SF1 to SF4 and SF7, the reset period, the SW address period, and the erase period are set the same for each subfield, while the sustain period is set to have different luminance weights. For example, the sustain periods of the first to fourth subfields SF1 to SF4 have luminance weights of 1, 2, 4, and 8, and the seventh subfield SF7 has a luminance weight of 16, respectively. .

Each of the fifth, sixth, and eighth subfields SF5, SF6, and SF8 of the SE method has a sustain period for the cell maintaining the on-state and the SE address period for selecting the off-cell as the erase discharge. Includes a sustain period to produce In these SE subfields SF5, SF6, SF8, the SE address period is set to be the same for each subfield, and the sustain period is set to be the same or different according to the luminance relative ratio. Here, the fifth and sixth subfields SF5 and SF6 are set to have the same luminance weight as that of the sustain period of the fourth subfield SF4 of the SW method that is the previous subfield, that is, the eighth subfield SF8. Is set to have the same luminance weight, that is, 16, as the sustain period of the seventh subfield SF7 of the SW method, which is the previous subfield. Each of the SE-type subfields SF5, SF6, SF8 is selectively turned off only for the discharge cells which remain on in the previous subfield.

For example, the fifth subfield SF5 selectively turns off cells that have remained in the fourth subfield SF4, and the sixth subfield SF6 is in the fifth subfield SF5. Selectively turn off the cells that have maintained, and the eighth subfield SF8 selectively turns off the cells that have remained in the seventh subfield SF7.

Accordingly, in the subfields SF5, SF6, and SF8 of the SE scheme, a separate front writing period for the SE address is not required, thereby reducing the contrast.

The combination of the luminance weights of the five SW subfields SF1 to SF4 and SF7 and the three SE subfields SF5, SF6 and SF8 makes the PDP driving method of the present invention 1 + 2 + 4 + 8 + 8 + 8 +. 16 + 16 = 64 basic gradations. For example, the subfield mapping method for implementing the basic 64 gradations is shown in Table 2 below.

As can be seen in Table 2, the first to fourth subfields SF1 to SF4 and the seventh subfield SF7 among the first to eighth subfields SF1 to SF8 are binary-coded. The fifth and sixth subfields SF5 and SF6 and the eighth subfield SF8 are linearly coded depending on the previous subfield. That is, each of the fifth and sixth subfields SF5 and SF6 and the eighth subfield SF8 driven by the SE method may be selectively turned off only when the previous subfield is turned on. For example, in the case of displaying the gradation value 32, it is turned off in the first to third subfields SF1 to SF3 by the binary coding, turned on in the fourth and seventh subfields SF4 and SF7, and by linear coding. The fifth subfield SF5 subsequent to the fourth subfield SF4 is turned on, and is turned off in the sixth and eighth subfields SF6 and SF7.

On the other hand, when the subfields are mapped as shown in Table 2, contour noise may occur at grayscale values 7 and 8, 15, and 16, etc., but this is because two frame combination methods similar to the previous grayscale value and the emission pattern (AB) are used. This can be prevented by rearranging with mapping. For example, in the case of expressing 8 gradations adjacent to 7, the rear frame is rearranged to implement 12 gradations in the first frame, and 6 gradations in the second frame, and then implemented as a combination of the first and second frames. Can be prevented.

As described above, in the PDP driving method according to the present invention, 64 basic grayscales are implemented by combining five SW subfields SF1 to SF4 and SF7 and three SE subfields SF5, SF6 and SF8. The basic gradation is extended to 256 gradations by subdividing using an error diffusion method or a dithering method. In other words, the PDP driving method according to the present invention implements the basic gradation obtained by dividing the 256 gradations into 64 as shown in FIG. 5 using the subfield mapping method described above, and at least four levels of gradations between the basic gradations are LSB 2-bit. Is implemented by compensating with an error diffusion method or a dithering method. As a result, in the PDP driving method according to the present invention, since the total number of subfields constituting one frame is eight, the address period can be sufficiently secured, so that even a single scan method can drive an HD PDP of 720 scan lines or more. do.

6 illustrates a PDP driving apparatus according to an embodiment of the present invention. The PDP driving apparatus shown in FIG. 6 includes a gamma correction unit 30, an error diffusion unit 32, a subfield mapping unit 34, and a data driver 36 connected between an input line of video data and the PDP 38. It is provided.

The gamma correction unit 30 receives digital video data gamma-corrected to suit the luminance characteristic of the cathode ray tube (CRT) from outside, that is, video data to be supplied to each of the cells (sub pixels) constituting the PDP 38. . The gamma correction unit 30 performs inverse gamma correction on each of the input video data to make the luminance characteristic according to the video data linear. For example, the gamma correction unit 30 outputs inverse gamma corrected video data corresponding to the input video data by using a lookup table (LUT) that is set so that luminance characteristics according to the video data follow a 2.2 gamma curve.

The error diffusion unit 32 outputs video data having a reduced number of bits by correcting each of the video data from the gamma correction unit 30 by an error diffusion method. In other words, the error diffusion unit 32 calculates the error diffusion coefficients of the video data from the gamma correction unit 30 and the adjacent pixels calculated through the error diffusion filter to reduce the number of bits of the video data by outputting the error diffusion coefficient. do.

For example, the error diffusion unit 32 stores the lower two bits of the 8-bit video data input from the gamma correction unit 30 in a built-in line memory to be used for the error diffusion operation of pixels adjacent thereto. The error diffusion unit 32 reads the lower two bits of adjacent video data stored in the line memory and calculates error diffusion coefficients by assigning different weights according to the positions of the pixels as shown in FIG. 7. Referring to FIG. 7, when performing an error diffusion operation on the current P5 pixel, the error diffusion unit 32 assigns a weight of 1/16 to the lower 2 bits of the P1 pixel adjacent to the P5 pixel, and lower 2 bits of the P2 pixel. Gives a weight of 5/16, a weight of 3/16 in the lower 2 bits of the P3 pixel, and a weight of 7/16 in the lower 2 bits of the P4 to calculate an error diffusion coefficient for each of the P1 to P4 pixels. . The error diffusion unit 42 adds the calculated error diffusion coefficients of the adjacent pixels P1 to P4 to the lower two bits of the current pixel P6 data to generate a carry signal “0” or “1”. Subsequently, the generated carry signal is added to the upper six bits of the current video data to output six bits of video data.

The subfield mapping unit 34 maps each of the video data from the error diffusion unit 32 to a preset subfield pattern and outputs the mapping. In particular, when the subfield mapping unit 34 maps video data causing contour noise such as grayscale values 7 and 8, 15 and 16, and the like, the subfield mapping unit 34 is previously set by the two frame combining method (AB Mapping). Outputs the mapping to the subfield pattern.

The data driver 36 latches the input data which is separated bit by bit according to the subfield pattern in the subfield mapping unit 34, and then, when the horizontal line drives the latched data line by line, Supply to address electrode lines.

The PDP 38 includes an address electrode line and a pair of sustain electrode lines intersecting the address electrode line with the discharge space therebetween. Each cell having a discharge space corresponding to the subpixel is formed at each intersection of the address electrode line and the sustain electrode line pair. The PDP 38 is a cell to be turned on or off by the address discharge according to the data supplied from the data driver 36 to the address electrode line whenever the scan electrode line of the sustain electrode line pair is driven in the address period of each subfield. Select them. The PDP 38 causes the cells that are on or remain in the address period to maintain the discharge in the sustain period of each subfield by driving the sustain electrode line pair. In this case, as the number of bits of video data is reduced, the number of subfields constituting one frame is reduced to eight, so that the address period can be sufficiently secured, so that the HD class PDP 38 can be driven even by the single scan method. In addition, the 64 basic gray scales implemented by the eight subfield combinations are divided by the error diffusion unit 32 to represent 256 gray scales.

The error diffusion unit 32 that increases the gray scale expression power may be replaced by the dithering unit 42 as shown in FIG. 8. The dithering unit 42 shown in FIG. 8 generates a carry signal added to the remaining upper 6 bits by using a dither mask pattern having a lower 2 bits of 8-bit video data having a corresponding 2x2 cell size. To this end, the dithering unit 42 stores dither mask patterns having different patterns for each gray level and for each frame in a table form. For example, the dithering unit 42 has a cell size of 2 × 2, and is divided into four gray levels, such as 0 to 3, corresponding to the lower two bits of the video data, and each of the four dither mask patterns. The dither mask pattern separated by at least two frames is stored again. By using the dither mask pattern, the position of the on cell corresponding to "1" is distributed spatially and temporally, thereby increasing the gray scale expression power. The dithering unit 42 selects the lower 2 bits of the 8-bit video data input from the inverse gamma correction unit 30 and the dither value (0 or 1) of the corresponding position among the dither mask patterns corresponding to the frame. The selected dither value is added to the remaining upper six bits of video data and output to the subfield mapping unit 34.

As described above, the PDP driving method and apparatus according to the present invention can implement 64 basic gray levels in which contour noise is removed by combining five SW subfields and three SE subfields. In addition, the PDP driving method and apparatus according to the present invention can increase the gradation expression power by subdividing the basic gradations using an error diffusion method or a dithering method. As a result, the method and apparatus for driving PDPs according to the present invention can drive HD-grade PDPs of 720 lines or more in a single scan method by reducing the number of subfields while preventing contour noise and increasing gray scale expression power.

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

1 is a perspective view showing a discharge cell structure of a conventional three-electrode AC surface discharge type plasma display panel.

2 is a diagram showing the configuration of one frame for a conventional plasma display panel driving method.

3 is a diagram illustrating a structure of one frame for another conventional plasma display panel driving method.

4 is a diagram illustrating the configuration of one frame for a plasma display panel driving method according to an exemplary embodiment of the present invention.

5 is a diagram illustrating basic gray scales implemented by a method of a plasma display panel according to an exemplary embodiment of the present invention.

6 is a block diagram illustrating a plasma display panel driving apparatus according to an exemplary embodiment of the present invention.

7 is a view for explaining an error diffusion method of an error diffusion unit illustrated in FIG. 6.

8 is a block diagram illustrating a plasma display panel driving apparatus according to another exemplary embodiment of the present invention.

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

10: upper substrate 18: lower substrate

12A: Scanning electrode 12B: Sustaining electrode

14 upper dielectric layer 16 protective film

20: data electrode 22: lower dielectric layer

24: partition 26: phosphor

30: gamma correction unit 32: error diffusion unit

34: subfield mapping unit 36: data driver

38: PDP 42: dithering unit

Claims (17)

A method of driving a plasma display panel with a combination of selective write subfields and selective erase subfields, the method comprising: Inverse gamma correction of the input video data; A carry signal is generated by adding lower bits of some of the inverse gamma corrected video data and error diffusion coefficients calculated by giving different weights to data of adjacent pixels to generate a carry signal, and apply the carry signal to the remaining upper bits of the video data. An error diffusion step of adding and error diffusion; The error-diffused video data is included in a subfield pattern arranged in the order of first to fourth selective write subfields, fifth and sixth selective erase subfields, seventh selective write subfields, and eighth selective erase subfields. And mapping the display on the plasma display panel. The method of claim 1, And the luminance weights of the first to fourth selective write subfields and the seventh selective write subfield are sequentially increased. The method of claim 1, The fifth and sixth selective erasure subfields have the same brightness weight as the fourth selective write subfield, And the eighth selective erasing subfield is set to have the same brightness weight as that of the seventh selective writing subfield. The method of claim 1, The first to fourth selective write subfields and the seventh selective write subfield are A reset period for initializing the cells of the full screen; An address period for turning on selected cells; And a sustain period for maintaining the discharge of the cells selected in the address period according to the luminance weight. The method of claim 4, wherein And the first to third selective write subfields further include an erase period for erasing all discharges after the sustain period. The method of claim 1, The fifth and sixth selective erasure subfields and the eighth selective erasure subfields are An address period for turning off selected ones of the cells which remain on from the previous subfield; And a sustain period for causing discharge of cells that remain in an on state other than the selected cell according to a corresponding luminance weight. delete delete delete A method of driving a plasma display panel with a combination of selective write subfields and selective erase subfields, the method comprising: Inverse gamma correction of the input video data; The lower bit of the reverse gamma corrected video data is used to select the corresponding gray level among the dither mask patterns and the dither value of the corresponding position in the dither mask pattern of the frame, and the upper bit of the remaining part of the video data. Dithering the dither by adding the selected dither value to each field; The error-diffused video data is included in a subfield pattern arranged in the order of first to fourth selective write subfields, fifth and sixth selective erase subfields, seventh selective write subfields, and eighth selective erase subfields. And mapping the display on the plasma display panel. An apparatus for driving a plasma display panel with a combination of selective write subfields and selective erase subfields, the apparatus comprising: A gamma correction unit configured to inverse gamma correct the input video data; A carry signal is generated by adding lower bits of some of the inverse gamma corrected video data and error diffusion coefficients calculated by giving different weights to data of adjacent pixels, and generating the carry signal by applying the generated carry signal to the rest of the video data. An error diffusion unit for adding and outputting bits; The error-diffused video data is included in a subfield pattern arranged in the order of first to fourth selective write subfields, fifth and sixth selective erase subfields, seventh selective write subfields, and eighth selective erase subfields. A subfield mapping unit for mapping and outputting; And a data driver for driving the plasma display panel according to the video data output from the subfield mapping unit. The method of claim 11, And the luminance weights of the first to fourth selective write subfields and the seventh selective write subfield are sequentially increased. The method of claim 11, The fifth and sixth selective erasure subfields have the same brightness weight as the fourth selective write subfield, And the eighth selective erasing subfield is set to have the same brightness weight as that of the seventh selective writing subfield. delete delete delete An apparatus for driving a plasma display panel with a combination of selective write subfields and selective erase subfields, the apparatus comprising: A gamma correction unit configured to inverse gamma correct the input video data; The lower bit of the reverse gamma corrected video data is used to select the corresponding gray level among the dither mask patterns and the dither value of the corresponding position in the dither mask pattern of the frame, and the upper bit of the remaining part of the video data. A dithering unit which adds and outputs the selected dither value; The dithered video data is mapped to subfield patterns arranged in the order of first to fourth selective write subfields, fifth and sixth selective erase subfields, seventh selective write subfields, and eighth selective erase subfields. A subfield mapping unit to output the result; And a data driver for driving the plasma display panel according to the video data output from the subfield mapping unit.