KR100555305B1 - Apparatus And Method For Driving Plasma Display Panel - Google Patents

Abstract

The present invention relates to an apparatus and method for driving a plasma display panel to improve display quality.

The apparatus and method for driving the plasma display panel count the on data for each subfield to detect the load of the subfield and adjust the arrangement of the subfield according to the load of the subfield.

Description

Driving apparatus for plasma display panel and driving method thereof {Apparatus And Method For Driving Plasma Display Panel}             

1 is a block diagram showing a driving apparatus of a conventional plasma display panel.

2 is a block diagram illustrating an apparatus for driving a plasma display panel according to a first embodiment of the present invention.

3 is a graph illustrating an example of load distribution for each subfield in input data.

4 is a diagram illustrating in detail a subfield arrangement adjusting unit illustrated in FIG. 2.

5A to 5C are diagrams illustrating subfields rearranged by the subfield alignment units shown in FIG. 4.

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

7A through 7C are graphs showing gray level distributions of various data.

FIG. 8 is a block diagram illustrating in detail a subfield array selection unit illustrated in FIG. 6.

9 is a block diagram illustrating an apparatus for driving a plasma display panel according to a third embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

1: On data calculation unit for each subfield 2: Subfield layout adjustment unit

3, 6: data driver 4: sustain pulse number adjusting unit

5: subfield array selection unit 7: gray level detection unit

8: Random Number Generator 9: Subfield Arrangement / Array Arrangement

11A, 11B, 21A, 21B, 61A, 61B: Inverse gamma adjustment unit

12, 22, 62: gain adjustment part 13, 23, 63: error diffusion part

14, 24, 64: subfield mapping unit 15, 25, 65: memory

16, 26, 66: data alignment unit 17, 27, 67: APL control unit

41 to 4n: subfield alignment unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to an apparatus and method for driving a plasma display panel to improve display quality.

The plasma display panel (hereinafter referred to as "PDP") displays an image using visible light generated from the phosphor when the ultraviolet rays generated by the gas discharge excite the phosphor. The PDP is thinner and lighter than the cathode ray tube (CRT), which has been the mainstay of the display means, and is more advantageous for realizing high definition / large screen.

The PDP has an upper substrate and a lower substrate which are installed to face each other with partition walls therebetween. The upper substrate has first and second electrodes formed in a direction crossing the partition wall. The lower substrate includes an address electrode formed in a direction parallel to the partition wall, and a dielectric layer formed to cover the address electrode. The discharge cell is positioned at the intersection of the first electrode, the second electrode, and the address electrode.

The PDP is driven by dividing one frame into several subfields having different number of emission times in order to realize gray level of an image. Each subfield is divided into a reset period for uniformly generating a discharge, an address period for selecting a discharge cell, and a sustain period for implementing gray levels according to the number of discharges. For example, when the image is to be displayed with 256 gray levels, the frame period (16.67 ms) corresponding to 1/60 second is divided into eight subfields. In addition, each of the eight subfields is divided into an address period and a sustain period. Here, while the reset period and the address period of each subfield are the same for each subfield, the sustain period and the number of discharges thereof are 2n (n = 0,1,2,3,) in each subfield in proportion to the number of sustain pulses. 4,5,6,7). As described above, since the sustain period is changed in each subfield, gray levels of an image can be realized.

Referring to FIG. 1, the driving apparatus of the PDP includes first and second inverse gamma adjusting units 11A and 11B, a gain adjusting unit 12, an error diffusion unit 13, a subfield mapping unit 14, and a memory 15. And a data alignment unit 16 and an average picture level control (hereinafter referred to as "APL") control unit 17.

Each of the first and second inverse gamma adjusting units 11A and 11B linearly converts luminance values according to grayscale values of the video data by performing inverse gamma correction on the video data from the input line 10.

The gain adjusting unit 12 adjusts gain by amplifying the red, green, and blue video data corrected by the first inverse gamma adjusting unit 11A by an effective gain. In addition, the gain adjusting unit 12 adjusts the gain with respect to the red, green, and blue video data input from the first inverse gamma adjusting unit 11A in accordance with the APL detected by the APL control unit 17.

The error diffusion unit 13 finely adjusts the luminance value by diffusing an error component to adjacent cells with respect to the data from the gain adjustment unit 12. To this end, the error diffusion unit 13 divides the data into an integer part and a decimal part, and multiplies the decimal part by a Floyd-Steinberg coefficient to spread error components in adjacent cells.

The subfield mapping unit 14 maps the data from the error diffusion unit 13 to a preset subfield pattern and supplies the data to the data alignment unit 16.

The data aligning unit 16 stores the video data input from the subfield mapping unit 14 in the memory 15, reads the data stored in the memory 15, and supplies the data to the data driving unit of the PDP (not shown). The data driver of the PDP includes integrated circuits (hereinafter referred to as " IC ") connected to each of the plurality of address electrodes formed on the PDP, and inputs data input from the data alignment unit 12 to the address electrodes of the PDP. Supply.

The APL control unit 17 detects an average brightness per frame of video data input from the second inverse gamma adjusting unit 11B, that is, APL, and outputs sustain pulse number information corresponding to the detected APL. The APL detected by this APL control unit 17 is input to the gain adjusting unit 12, and the sustain pulse number information is input to a timing controller (not shown). The timing controller adjusts the number of sustain pulses by controlling a circuit for generating sustain pulses according to the sustain pulse number information supplied from the APL control unit 17.

However, the conventional apparatus and method for driving a PDP has a problem in that contour noise appears in a moving image due to discontinuity of light generated when subfields having different luminance weights are turned on / off in the arrangement of subfields. This contour noise makes the brightness at the contours felt by the retina following the moving object appear darker or brighter than the input data when displaying moving pictures with a constant subfield arrangement.

However, the conventional PDP driving apparatus and method have a limitation in gradation expression by adjusting only a sustain pulse according to a predetermined subfield pattern and average brightness per frame of video data, that is, APL.

Due to the limitation of the contour noise and the gradation expression ability, the conventional PDP has not reached a satisfactory level of display quality.

Accordingly, an object of the present invention is to provide an apparatus and method for driving a plasma display panel to increase display quality by increasing gray scale expressing ability and reducing contour noise.

In order to achieve the above object, a driving apparatus of a PDP according to the first embodiment of the present invention includes a sub-field on data calculator for counting on-data for each subfield and detecting a load of the subfield; And an adjusting unit for adjusting the arrangement of the subfields according to the load of the subfields.

The weight of the subfield is maintained at a preset weight even after the arrangement of the subfield is adjusted.

The adjusting unit arranges the subfields in order of increasing load of the subfields.

The adjusting unit arranges the subfields in a descending order of the load of the subfields.

According to a second aspect of the present invention, there is provided a driving apparatus of a PDP, comprising: a gray level detector for detecting gray level distribution of data; And an adjusting unit for adjusting at least one of the number of sustain pulses and the subfield arrangement according to the gray level distribution of the data.

The adjusting unit adjusts both the number of sustain pulses and the subfield arrangement according to the gray level distribution of the data.

The adjusting unit may reduce the number of sustain pulses when the gray levels of the data concentrate on low gray levels.

The adjusting unit may increase the number of the sustain pulses when the gray levels of the data concentrate on a high gray level.

A driving apparatus of a PDP according to the third embodiment of the present invention includes a random number generator for randomly generating random numbers; And an adjusting unit for adjusting at least one of the number of sustain pulses, the subfield arrangement, and the subfield arrangement in accordance with the random number.

A driving method of a PDP according to a first embodiment of the present invention includes the steps of counting on data for each subfield and detecting a load of the subfield; Adjusting the arrangement of the subfields according to the load of the subfields.

The adjusting of the arrangement of the subfields may include arranging the subfields in order of increasing load of the subfields.

The adjusting of the arrangement of the subfields may include arranging the subfields in descending order of loading of the subfields.

A driving method of a PDP according to a second embodiment of the present invention includes detecting a gray level distribution of data; And adjusting at least one of the number of sustain pulses and the subfield arrangement according to the gray level distribution of the data.

Adjusting at least one of the number of sustain pulses and the subfield arrangement is characterized in that both the number of sustain pulses and the subfield arrangement are adjusted according to the gray level distribution of the data.

Adjusting at least one of the number of sustain pulses and the subfield arrangement may reduce the number of sustain pulses when the gray levels of the data concentrate on low gray levels.

Adjusting at least one of the number of sustain pulses and the subfield arrangement may increase the number of the sustain pulses when the gray levels of the data concentrate on high gray levels.

A method of driving a PDP according to a third embodiment of the present invention includes the steps of: randomly generating a random number; Adjusting at least one of a sustain pulse number, a subfield arrangement, and a subfield arrangement according to the random number.

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

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 2 to 9.

Referring to FIG. 2, the driving apparatus of the PDP according to the first embodiment of the present invention includes first and second inverse gamma adjustment units 21A and 21B, a gain adjustment unit 22, an error diffusion unit 23, and subfield mapping. On-data calculation unit for each subfield connected between the unit 24, the memory 25, the data alignment unit 26 and the APL control unit 27, and the subfield mapping unit 24 and the data alignment unit 26 ( 1) and the subfield arrangement adjusting unit 2.

Each of the first and second inverse gamma adjusting units 21A and 21B linearly converts the luminance value according to the gray value of the video data by performing inverse gamma correction on the video data from the input line 20.

The gain adjusting unit 22 adjusts the gain by amplifying the red, green, and blue video data corrected by the first inverse gamma adjusting unit 21A by the effective gain. In addition, the gain adjusting unit 22 adjusts gain with respect to the red, green, and blue video data input from the first inverse gamma adjusting unit 21A in accordance with the APL detected by the APL control unit 27.

The error diffusion unit 23 finely adjusts the luminance value by diffusing an error component to adjacent cells with respect to the data from the gain adjustment unit 22.

The subfield mapping unit 24 maps the data from the error diffusion unit 23 to a preset subfield pattern and supplies the data to the on data calculator 1 for each subfield.

The on-data calculation unit 1 for each subfield counts on data for each subfield of data input from the subfield mapping unit 24 to calculate a load for each subfield. 3 shows an example of the on data amount of each subfield, that is, the load for each subfield, calculated by the on data calculation unit 1 for each subfield.

The subfield arrangement adjusting unit 2 rearranges the subfields while maintaining the luminance weight of each subfield according to the on data information input from the on data calculation unit 1 for each subfield.

The data aligning unit 26 stores the video data input from the subfield arrangement adjusting unit 2 in the memory 25, reads out the data stored in the memory 25, and supplies the data data to the data driving unit 3 of the PDP. The data driver 3 of the PDP supplies the data input from the data alignment unit 26 to the address electrodes of the PDP including ICs connected to each of the plurality of address electrodes formed in the PDP.

The APL control unit 27 detects the average brightness per frame of the video data input from the second inverse gamma adjusting unit 21B, that is, APL, and outputs sustain pulse number information corresponding to the detected APL. The APL detected by this APL control unit 27 is input to the gain adjusting unit 22, and the number of sustain pulses is input to a timing controller (not shown). The timing controller adjusts the number of sustain pulses by controlling a circuit for generating sustain pulses according to the sustain pulse number information supplied from the APL control unit 27.

The function and operation of the subfield arrangement adjustment unit 2 will be described in detail with reference to FIGS. 4 to 5C.

4, the subfield arrangement adjusting unit 2 includes n subfield alignment units 41 to 4n (where n is a natural number) for rearranging the subfields under different criteria.

The first subfield aligning unit 41 rearranges the subfields in order of increasing load of the subfields while maintaining the luminance weight of each subfield. Assuming that the load of each subfield calculated by the on-data calculation unit 1 for each subfield is the same as that of FIG. 3, the first subfield alignment unit 41 is the third subfield having the highest load as shown in FIG. 5A. The fifth subfield SF5, the seventh subfield SF7, the second subfield SF2, and the sixth subfield SF6 are arranged first in the data of the field SF3 and in the order of low load thereafter. The first subfield SF1, the fourth subfield SF4, and the eighth subfield SF8 are disposed.

The second subfield aligning unit 42 rearranges the subfields in the order of low load of the subfields while maintaining the luminance weight of each subfield. Assuming that the load of each subfield calculated by the on-data calculation unit 1 for each subfield is the same as that of FIG. 3, the second subfield alignment unit 42 has the eighth subfield having the lowest load as shown in FIG. 5B. The fourth subfield SF4, the first subfield SF1, the sixth subfield SF6, the second subfield SF2, The seventh subfield SF7, the fifth subfield SF5, and the third subfield SF3 are arranged.

The third subfield arranging unit 43 rearranges some subfields in the order of the high load of the subfields while maintaining the luminance weight of each subfield, and the remaining subfields in the order of the low load between the subfields. Rearrange Assuming that the load of each subfield calculated by the on-data calculation unit 1 for each subfield is as shown in FIG. 3, the third subfield aligning unit 43 is the third subfield having the highest load as shown in FIG. 5C. After arranging the data of the SF3 first, the eighth subfield SF8 having the lowest load is disposed, and after that, the fifth subfield SF5, the fourth subfield SF4, and the seventh subfield ( SF7), a first subfield SF1, a second subfield SF2, and a sixth subfield SF4 are arranged.

Output data of the subfield alignment units 41 to 4n may be constantly selected as output data of a specific subfield alignment unit, or output data of two or more subfield alignment units may be arranged periodically or aperiodically. For example, output data of the first subfield sorter 41 may be supplied to the data sorter 26, and output data of the first subfield sorter 41 may be supplied to the data sorter 26. First, the output data of the second subfield alignment unit 42 may be supplied to the data alignment unit 26.

When the subfields are arranged in the order of high load or low load, the discharge cells emit light continuously and the difference in the number of light emission between successive subfields is not so large. Does not appear

6 shows an apparatus for driving a PDP according to a second embodiment of the present invention.

Referring to FIG. 6, the driving apparatus of the PDP according to the embodiment of the present invention includes the first and second inverse gamma adjusting units 61A and 61B, the gain adjusting unit 62, the error diffusion unit 63, and the subfield mapping unit ( 64), the memory 65, the data alignment unit 66 and the APL control unit 67, the gray level detection unit 7 for detecting the gray level distribution of the input data, and the number of sustain pulses according to the gray level distribution. A sustain pulse number adjusting section 4 for performing the selection, and a subfield array selecting section 5 for selecting the subfield array according to the gray level distribution.

The first and second inverse gamma adjustment units 61A and 61B, the gain adjustment unit 62, and the error diffusion unit 63 are substantially the same as in the above-described embodiment.

The APL control unit 67 detects the average brightness per frame of the video data input from the second inverse gamma adjusting unit 61B, that is, APL, and outputs sustain pulse correction information corresponding to the detected APL. The APL detected by this APL control section 67 is input to the gain adjusting section 22, and the number of sustain pulses is input to the sustain pulse number adjusting section 4.

The gray level detection unit 7 obtains the entire distribution of each gray level, i.e., histogram, from the input line 60 in units of frames. The gray level detection unit 7 supplies the detected gray level distribution to the sustain pulse number adjusting unit 4 and the subfield array selection unit 5. In addition, the gray level detection unit 7 may detect the gray level distribution GR of data by dividing it into predetermined sections. For example, the gray level detector 7 includes a first section between 0 and 32, a second section between 33 and 64, a third section between 65 and 96, a fourth section between 97 and 128, and 129 to 160 The gray level distribution can be detected by dividing into a fifth section, a fifth section 161 to 192, a sixth section between 193 to 224, a seventh section between 225 to 256, and the like.

The sustain pulse number adjusting unit 4 adjusts the number of sustain pulses input from the APL control unit 42 according to the gray level distribution GR. If the data of low gradation in the gray level distribution GR is larger than the data of other gradations, the sustain pulse number adjusting unit 4 reduces the number of sustain pulses below a preset reference value to control darker images darker. On the contrary, if the data of high gradation in the gray level distribution GR is larger than the data of other gradations, the sustain pulse number adjusting unit 4 increases the number of sustain pulses above a preset reference value to control bright images more brightly.

The subfield array selection section 5 includes a subfield array in which a low gradation expression is emphasized, a subfield array in which a middle gradation expression is emphasized, a subfield array in which a high gradation expression is emphasized, a subfield array in which outline noise is hardly observed, and the like. It is stored in advance. The subfield array selection unit 5 selects a specific subfield array from among a plurality of subfield arrays set in advance according to the gray level distribution GR from the gray level detection unit 7. If some of the subfield arrays stored in the subfield array selection unit 5 are as shown in Table 1 below, and data of gray level where contour noise may appear is inputted, the subfield array selection unit 5 determines the value of 'array1'. Select subfield array or subfield array of 'array2'. When data whose data value changes from 127 to 128 is input, the subfield array selection unit 5 selects a subfield array of 'array 2' to reduce contour noise. When data whose data value is changed from 32 to 64 is input, the subfield array selection unit 5 selects a subfield array of 'array 3' to reduce contour noise.

The subfield mapping unit 64 maps the data from the error diffusion unit 23 to the subfield array selected by the subfield array selection unit 5 and supplies the data to the data alignment unit 66.

The data alignment unit 66 stores the video data input from the subfield mapping unit 64 in the memory 65, reads out the data stored in the memory 65, and supplies the data to the data driver 68 of the PDP. The data driver 68 of the PDP supplies the data input from the data alignment unit 66 to the address electrodes of the PDP including ICs connected to each of the plurality of address electrodes formed on the PDP.

7A-7C show examples of gray distribution of input data.

FIG. 7A illustrates a case where data of intermediate gradation is many among data for one frame, and FIG. 7B illustrates a case where data of low gradation is many. 7C illustrates a case where there are many high gray levels of data. When such data are input, the driving apparatus and method of the PDP according to the second embodiment of the present invention detects the gray level distribution of the data, and sustain pulses by varying the number of sustain pulses and the subfield array according to the detected gray level distribution. By adjusting the number and subfield arrangement, the gradation expression is improved and the contour noise is reduced.

8 shows the subfield array selection unit 5 in detail.

Referring to FIG. 8, the subfield array selection unit 5 includes a memory 82 in which n subfield arrays are stored, and a selector 83 for controlling the memory 82.

The selector 83 selects a specific subfield array from the n subfield arrays stored in the memory 82 according to the gray level distribution 7 from the gray level detector 7. The selector 83 supplies the selected subfield array to the subfield mapping unit 64.

9 shows a driving apparatus of a PDP according to a third embodiment of the present invention.

Referring to FIG. 9, the driving apparatus of the PDP according to the first embodiment of the present invention includes the first and second inverse gamma adjustment units 81A and 81B, the gain adjustment unit 82, the error diffusion unit 83, and the subfield mapping. The unit 84, the memory 85, the data alignment unit 86, and the APL control unit 87, the random number generator 8 for generating a random number, the random number generator 8, and the subfield mapping unit 84 Subfield arrangement / array adjustment part 9 connected between them is provided.

Each of the first and second inverse gamma adjusting units 81A and 81B linearly converts the luminance value according to the gray value of the video data by performing inverse gamma correction on the video data from the input line 80.

The gain adjusting unit 82 amplifies the red, green, and blue video data corrected by the first inverse gamma adjusting unit 81A by the effective gain to adjust the gain. In addition, the gain adjusting unit 82 adjusts the gain with respect to the red, green, and blue video data input from the first inverse gamma adjusting unit 81A in accordance with the APL detected by the APL control unit 87.

The error diffusion unit 83 finely adjusts the luminance value by diffusing an error component to adjacent cells with respect to the data from the gain adjusting unit 82.

The subfield mapping unit 84 maps the data from the error diffusion unit 83 to the subfield arrangement selected by the subfield arrangement / arrangement adjustment unit 9.

The data alignment unit 86 stores the data from the subfield mapping unit 84 in the memory 85, reads out the data stored in the memory 85, and supplies the data to the data driver 88 of the PDP. The data driver 88 of the PDP supplies data input from the data alignment unit 86 to the address electrodes of the PDP, including ICs connected to each of the plurality of address electrodes formed in the PDP.

The APL control unit 87 detects the average brightness per frame of the video data input from the second inverse gamma adjustment unit 81B, that is, APL, and outputs sustain pulse correction information corresponding to the detected APL. The APL detected by this APL control section 87 is input to the gain adjustment section 82, and the number of sustain pulses is input to the timing controller. The timing controller adjusts the number of sustain pulses by controlling a circuit for generating sustain pulses according to the sustain pulse number information supplied from the APL control unit 87.

The random number generator 8 arbitrarily generates a random number RD and supplies the random number to the subfield arrangement / arrangement adjustment unit 8.

The subfield arrangement / array adjustment unit 9 stores a plurality of subfield arrangements having different subfield arrangements, the number of subfields, and the weights of the subfields. This subfield arrangement / arrangement adjustment unit 9 selects a subfield array corresponding to the random number RD from the random number generator 8 and supplies it to the subfield mapping unit 84.

As a result, the driving apparatus and method of the PDP according to the third embodiment of the present invention arbitrarily change the arrangement of the subfields, the weight of the subfields, or the number of subfields, thereby minimizing the contour noise that may appear in a certain subfield arrangement. .

As described above, the driving apparatus and method of the PDP according to the present invention rearranges the data according to the load difference of the subfields, or changes the subfield arrangement or the subfield arrangement arbitrarily according to the gray level distribution of the data. As a result, the driving apparatus and method of the PDP according to the present invention improves the display quality by increasing the gray scale expressing ability and minimizing the contour noise.

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.

Claims (18)

An apparatus for driving a plasma display panel by time-dividing one frame period into a plurality of subfields each of which is weighted, An on data calculator for each subfield for counting on data for each subfield and detecting a load of the subfield; And adjusting an arrangement of the subfields in order of increasing load of the subfields or adjusting the arrangement of the subfields in order of decreasing load of the subfields according to the load difference of the subfields. A driving device of the plasma display panel. The method of claim 1, The weight of the subfield is maintained at a preset weight even after the arrangement of the subfield is adjusted. delete delete An apparatus for driving a plasma display panel by time-dividing one frame period into a plurality of subfields each of which is weighted, A gray level detector for detecting gray level distribution of data; And an adjusting unit for adjusting the subfield arrangement according to the gray level distribution of the data. delete The method of claim 5, wherein The adjusting unit, And if the gray levels of the data concentrate on low gray levels, the number of sustain pulses is reduced. The method of claim 5, wherein The adjusting unit, And the number of sustain pulses is increased when the gray levels of the data are concentrated in a high gradation. An apparatus for driving a plasma display panel by time-dividing one frame period into a plurality of subfields each of which is weighted, A random number generator for randomly generating a random number; And an adjusting unit for adjusting at least one of the subfield arrangement and the subfield arrangement according to the random number. A method of driving a plasma display panel by time-dividing one frame period into a plurality of subfields each of which is weighted, Counting on data for each subfield to detect a load of the subfield; Arranging the subfields in order of increasing load of the subfields or arranging the subfields in order of decreasing load of the subfields according to the load difference of the subfields. Driving method. The method of claim 10, And the weight of the subfield is maintained at a predetermined weight even after the arrangement of the subfield is adjusted. delete delete A method of driving a plasma display panel by time-dividing one frame period into a plurality of subfields each of which is weighted, Detecting a gray level distribution of the data; And adjusting the subfield arrangement according to the gray level distribution of the data. delete The method of claim 14, Adjusting the subfield arrangement, And when the gray levels of the data concentrate on low gray levels, the number of sustain pulses is reduced. The method of claim 14, Adjusting the subfield arrangement, And increasing the number of sustain pulses when the gray levels of the data are concentrated in a high gradation. A method of driving a plasma display panel by time-dividing one frame period into a plurality of subfields each of which is weighted, Optionally generating a random number; And adjusting at least one of a subfield arrangement and a subfield arrangement according to the random number.

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