KR100596238B1 - Driving Method of Plasma Display Panel and Driving Apparatus Thereof - Google Patents

Abstract

The present invention relates to a method and apparatus for driving a plasma display panel. A method of driving a plasma display panel of the present invention includes the steps of outputting an odd subfield sequentially to one of a plurality of blocks, and then sequentially outputting even subfields; And then outputting odd-numbered subfields sequentially to other blocks among the plurality of blocks. In addition, the driving apparatus of the plasma display panel of the present invention includes a driving unit for driving the plasma display panel divided into a plurality of blocks; The odd-numbered subfields are sequentially output to one of the plurality of blocks, and the even-numbered subfields are sequentially output, and the even-numbered subfields are sequentially output to the other blocks of the plurality of blocks. And a controller for controlling the driver to sequentially output fields. According to the present invention, the operating characteristics of the cell can be stabilized and the controller noise can be eliminated, and the luminance difference between the screens is compensated by emitting different discharge times for each subfield or block. In addition, the present invention can display images with different brightness for each subfield or for each block to obtain an even picture quality.

Plasma, Display, Panel, Pseudocontour, Subfield, Block

Description

Driving method and apparatus for plasma display panel {Driving Method of Plasma Display Panel and Driving Apparatus Thereof}

1 is a view schematically showing one frame of a conventional subfield driving method.

FIG. 2 is a waveform diagram illustrating driving pulses supplied to one subfield in FIG. 1. FIG.

FIG. 3 is a diagram illustrating a duty ratio of a sustain pulse supplied to each subfield in FIG. 1. FIG.

Fig. 4 is a characteristic diagram showing non-linear characteristics in gray scale expression by the conventional subfield driving method.

Fig. 5 is a diagram showing a discharge period when the gradation value changes from 128 to 127.

Fig. 6 is a diagram showing luminance perceived in still pictures and moving pictures.

Fig. 7 is a diagram showing peak white levels when a gray scale value changes.

Fig. 8 is a diagram showing black levels when gray level values change.

9 is a diagram showing a gray scale control method of a plasma display panel according to a first embodiment of the present invention;

FIG. 10 is a diagram showing an example of subfields applied to each block shown in FIG. 9; FIG.

11 is a block diagram illustrating a driving device of a plasma display panel according to an embodiment of the present invention.

12 is a view showing in detail the driving device of the plasma display panel shown in FIG.

FIG. 13 is a diagram illustrating a gray scale control method of a plasma display panel according to a second exemplary embodiment of the present invention. FIG.

FIG. 14 shows a subfield applied to each block shown in FIG. 13; FIG.

Fig. 15 is a characteristic diagram showing linear characteristics in gray scale expression for the present invention.

<Description of Symbols for Main Parts of Drawings>

1,2,11,12,13,14: Block 3: PDP

4 controller 5 memory controller

6,7: first and second scan / sustain driver
8,9: first and second common sustain drive unit

10A, 10B: first and second address driver

The present invention relates to a method and apparatus for driving a plasma display panel, and more particularly, to a method and apparatus for driving a plasma display panel capable of effectively removing the controller noise.

Plasma Display Panel (hereinafter referred to as "PDP") is an image display device using gas discharge. As a result of recent development efforts, image quality is improved in a large screen. PDP is roughly classified into a direct current (DC) method and a direct current (AC) method of surface discharge according to its driving method. AC type PDP has the advantages of low power consumption and life time compared to DC type. The gray scale representation method of the PDP is generally performed by a sub-field method.

When expressing 256 gray levels, the subfield method time-divisions an image of one field for 16.67 ms into eight subfields SF1 to SF8 as shown in FIG. Each subfield SF1 to SF8 has a reset period for initializing the full screen as shown in FIG. 2, an address period for writing data while scanning the full screen in a line-sequential manner, and a cell in which the data is written. It is divided into a sustain period for maintaining their light emission state.

Referring to FIG. 2, the screen is initialized by a reset pulse applied between the address electrode (X electrode) and the common sustain electrode (Z electrode) during the reset period, and the scanning pulse is applied to the scan / sustain electrode (Y electrode) in the address period. Are sequentially applied and data is supplied to the address electrode (X electrode) in synchronization with the scanning pulse. In the sustain period, sustain pulses are applied at the same duty ratio to the scan / sustain electrode (Y electrode) and the common sustain electrode (Z electrode) as shown in FIG. Here, the reset period and the address period of each subfield are the same for each subfield, while the sustain period is 2 ⁿ (n = 0,1,2,3,4,) in each subfield according to the luminance relative ratio as shown in FIG. 5, 6, 7) to increase in proportion. In this way, since the sustain period is different in each subfield, the gray scale of the image is expressed by adjusting the sustain period of each subfield, that is, the number of sustain discharges. In other words, the discharge periods of the subfields include one discharge period, two discharge periods, four discharge periods, eight discharge periods, 16 discharge periods, 32 discharge periods, 64 discharge periods, It is divided into 128 discharge periods. According to the combination of these discharge periods, 0 to 255 discharge periods are adjusted in one field period to adjust the brightness (brightness) of the gradation level.

However, in the gray scale expression method of the conventional subfield method, the luminance difference occurs depending on which subfield is placed between the subfield and the subfield due to the discharge characteristics of the PDP. That is, the gray level values 127 and 128 are one gray level, but the gray level value 127 is discharged as a sum of one discharge period to 64 discharge periods, while the gray level value 128 is discharged only in the eighth subfield SF8. Accordingly, as can be seen in FIG. 4, luminance or even a system is generated for each subfield, and gray scale expression is non-linear.

5 and 6, when the brightness level at one point is changed from another gray level value, for example, 128 to 127, the brightness perceived by a person becomes the brightness corresponding to 255 discharges instantaneously. . Accordingly, the brightness of the gray value perceived by a person changes from 128 to 255 and then falls to 127. Such noise is called contour noise, and when contour noise occurs, a pseudo outline appears on the screen. In other words, when the left half of the screen is displayed with a gray scale value of 128 and the right half of the screen is displayed with a gray scale value of 127, as shown in FIG. White (Peak White), or white bands, will appear. In addition, as shown in FIG. 8, when the left half of the screen is displayed with a gray scale value of 128 and the right half of the screen is displayed with a gray scale value of 127, the screen is moved to the right. That is, a black belt appears.

As a method for removing such noise, a method of rearranging the order of subfields, a method of dividing one subfield and adding one or two subfields, adding a subfield and rearranging the order of subfields A method of enumeration and an error diffusion method have been proposed. However, the method of adding subfields or rearranging the order of the subfields requires that the bit data be added from 8 bits to 10 bits or more, so that the sustain period is relatively reduced as the address period is lengthened, so the luminance is lowered. There is a problem. In addition, the error diffusion method has a disadvantage in that it is complicated to implement.

Accordingly, it is an object of the present invention to provide a gray scale control method and apparatus for a plasma display panel which can remove selector noise.

A method of driving a plasma display panel according to the present invention for achieving the above object is to divide the screen into at least two or more blocks, and to implement gradation by sequentially arranging one field into a plurality of subfields according to luminance relative ratios. A method of driving a plasma display panel, the method comprising: sequentially outputting odd-numbered subfields to one of the plurality of blocks, and then sequentially outputting even-numbered subfields; And outputting odd-numbered subfields sequentially after outputting even-numbered subfields sequentially to other blocks among the plurality of blocks.
According to such a feature, the subfields are sequentially assigned to other blocks in the order of the luminance relative ratio.
According to this feature, after the subfields are sequentially assigned to other blocks, the subfields are sequentially assigned to blocks in the reverse order of the assigned order.

According to another aspect of the present invention, a plasma display panel driving apparatus includes a plasma display panel driving apparatus that implements gradation by dividing a field into a plurality of subfields according to a luminance relative ratio. A driving unit driven by dividing into blocks; The odd-numbered subfields are sequentially output to one of the plurality of blocks, and the even-numbered subfields are sequentially output, and the even-numbered subfields are sequentially output to the other blocks of the plurality of blocks. And a controller for controlling the driver to sequentially output subfields.
According to such a feature, the controller controls the driver such that the subfields are sequentially assigned to other blocks in the order of the luminance relative ratio.
According to this aspect, the control unit controls the driving unit to be sequentially assigned to the blocks in the reverse order of the assigned order after the subfields are assigned to the other blocks in sequence.

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, a preferred embodiment of the present invention will be described with reference to FIGS. 9 to 15.

9 and 10, the gray scale control method of the PDP according to the first embodiment of the present invention drives the screen by dividing the screen into two divisions of the upper half block 1 and the lower half block 2. In one field, the upper half block 1 includes a first subfield SF1 having one discharge period, a third subfield SF3 having four discharge periods, and a fifth subfield having sixteen discharge periods. SF5), the seventh subfield SF7 having 64 discharge periods, the second subfield SF2 having two discharge periods, the fourth subfield SF4 having 8 discharge periods, and the 32 discharge periods. The branches are scanned and sustained in the order of the sixth subfield SF6 and the eighth subfield SF8 having the 128 discharge periods. On the other hand, the subfield applied to the lower half block 2 in one field includes the second subfield SF2 having two discharge periods, the fourth subfield SF4 having eight discharge periods, and the 32 discharge periods. Sixth subfield SF6 having an eighth subfield SF8 having a discharge period of 128 times, a first subfield SF1 having a first discharge period, and a third subfield SF3 having a fourth discharge period. , The fifth subfield SF5 having the 16th discharge period and the seventh subfield SF7 having the 64th discharge period are scanned and sustained in this order.

In the two-divided screen, subfields having the same discharge period are scanned and sustain discharged in different orders in the blocks (1, 2). That is, while the upper half block 1 is scanned and sustained discharged into the first subfield SF1, the lower half block 2 is scanned and sustained discharged into the second subfield SF2. The upper half block 1 includes the third subfield SF3, the fifth subfield SF5, the seventh subfield SF7, the second subfield SF2, the fourth subfield SF4, and the sixth subfield. While scanning and sustaining discharge in the order of the field SF6 and the eighth subfield SF8, the lower half block 2 is the fourth subfield SF4, the sixth subfield SF6, and the eighth subfield SF8. ), The first subfield SF1, the third subfield SF3, the fifth subfield SF5, and the seventh subfield SF7. Accordingly, subfields having the same discharge period are allocated to different blocks to be scanned and maintained in different orders. For example, the first subfield SF1 is allocated to the upper half block 1 so as to precede the other subfields. In contrast, in the lower half block 2, the first subfield SF1 is arranged in the order of the second subfield SF2, the fourth subfield SF4, the sixth subfield SF6, and the eighth subfield SF8. Assigned after scanning and maintenance discharge. Accordingly, the upper half block 1 and the lower half block 2 are scanned and sustained in different subfields at the same time, and emit light with different brightness, so that there is almost no noise.

11 and 12, the gray scale control apparatus of the PDP according to the present invention supplies a video signal to the PDP (3) and the PDP (3) which is driven in two divisions of the upper half block (1) and the lower half block (2) The first and second address drivers 10A and 10B, the memory controller 5 which relays the video signal toward the first and second address drivers 10A and 10B, and the upper half block 1 of the PDP 3. Scan / sustain driver 6 and first common sustain driver 8 for scanning and sustain driving, and second scan / sustain driver for scanning and sustain driving lower half block 2 of PDP 3; (7) and the second common sustain driver 9 to control the scan / sustain drivers 6 and 7 and the common sustain drivers 8 and 9 in response to the horizontal and vertical synchronization signals H and V. The control unit 4 is provided. The PDP 3 includes a pixel matrix composed of m × n pixels as shown in FIG. Each of the m × n pixels has a sustain electrode pair consisting of a scan / sustain electrode (hereinafter referred to as “Y electrode”) and a common sustain electrode (hereinafter referred to as “Z electrode”) and one address electrode (hereinafter referred to as “X electrode”). It is connected to this). The first address driver 10A is connected to the odd-numbered X electrodes X1, X3, ..., Xn-3, Xn-1, and the second address driver 10B is the even-numbered X electrodes X2, X4, ..., Xn-2, Xn). These first and second address drivers 10A, 10B are each of the odd-numbered X electrodes X1, X3, ..., Xn-3, Xn-1 and even-numbered X electrodes under the control of the memory controller 5, respectively. The bit data is simultaneously supplied to X2, X4, ..., Xn-2, Xn). The memory controller 5 collects bit data for each subfield and temporarily stores the bit data for each subfield, and supplies the bit data for each subfield to the first and second address drivers 10A and 10B. That is, the memory controller 5 supplies the least significant bit data LSB to the first and second address drivers 10A and 10B in the first subfield SF1 and the most significant bit in the eighth subfield SF8. The data MSB is supplied to the first and second address drivers 10A and 10B. The first scan / sustain driver 6 is connected to the upper half Y electrodes Y1, Y2, ..., Y (m / 2), and the first common sustain driver 8 is connected to the upper half Z electrodes Z1, Z2, ..., Z (m / 2)). The second scan / sustain driver 7 is connected to the lower half Y electrode Y (m / 2) +1, Y (m / 2) +2, ..., Ym, and the second common sustain driver 9 ) Is commonly connected to the lower half Z electrode (Z (m / 2) +1, Z (m / 2) +2, ..., Zm). The first and second scan / sustain drivers 6 and 8 select pixel lines to be displayed in the upper half block 1 and the lower half block 2 in the address period under the control of the controller 4, respectively. Positive electrode at upper half Y electrode (Y1, Y2, ..., Y (m / 2)) and lower half Y electrode (Y (m / 2) +1, Y (m / 2) +2, ..., Ym) Supply the sustain voltage of the castle. The first and second common sustain drivers 8 and 9 are each of the upper half Z electrodes Z1, Z2,..., Z (m / 2) and the lower half Z electrode Z in the sustain period under the control of the controller 4. The negative sustain voltage is supplied to (m / 2) + 1, Z (m / 2) +2, ..., Zm). The controller 4 generates the timing signals necessary for the scan / sustain drivers 6,7 and the common sustain drivers 8,9, and generates these timing signals with the scan / sustain drivers 7,8 and the common sustain. The PDP 3 is divided into the upper half block 1 and the lower half block 2 by being supplied to the driving units 8 and 9 to drive the PDP 3.

13 and 14, the gray scale control method of the PDP according to the second embodiment of the present invention is driven by dividing the screen into four first to fourth blocks 11 to 14. Within one field, the first block 11 is scanned and sustain discharged in the order of the first subfield SF1 having one discharge period and the eighth subfield SF8 having 128 discharge periods, and the second The block 12 is scanned and sustained in the order of the second subfield SF2 having two discharge periods and the seventh subfield SF7 having 64 discharge periods. In one field, the third block 13 is scanned and sustained in the order of the third subfield SF3 having four discharge periods and the sixth subfield SF6 having 32 discharge periods. The four blocks 14 are scanned and sustained in the order of the fourth subfield SF4 having the eight discharge periods and the fifth subfield SF5 having the sixteen discharge periods.

In the second embodiment of the present invention, subfields having different discharge periods and number of discharges are allocated in the first to fourth blocks 11 to 14 in one field, and different block data values are allocated. In other words, within one field, the subfields having the same number of discharges and discharge periods are assigned to only one of the first to fourth blocks 11 to 14.

When the screen is divided into four and the subfield and the block data value are supplied to each block differently in each field to drive the PDP, the gray scale control apparatus of the PDP uses the first to fourth blocks 11 to 14 in FIG. The scan / sustain driver and the common sustain driver must be divided into four parts to drive each.

As a result, in the PDP gray scale control method according to the second embodiment of the present invention, the scan and sustain pulses supplied to each block are composed of one subfield and assigned to different blocks for each field. Supplied differently. Accordingly, each of the first to fourth blocks 11 to 14 emits light with different brightness, and the same bit data is not supplied to the first to fourth blocks 11 to 14. On the other hand, since the number of discharges is different in the period during which the subfield is transitioned, there may be a difference in brightness for each transition period of each subfield. When each block emits light with different brightness and different bit data is supplied to each block in a different order, as shown in FIG. 15, the luminance is increased in the order of the first to eighth subfields SF1 to SF8. It is linearly increased, resulting in almost no controller noise. In other words, when an image, especially a moving picture, is displayed at different brightness in at least two or more blocks included in one screen, the subfields as the brightness level at a point changes from another gray level value, for example, 128 to 127 It is possible to prevent brightening or darkening beyond the normal brightness at the boundary or field boundary.

Meanwhile, in the gray scale control method of the PDP according to the present invention, subfields and blocks may be allocated in a form in which the first embodiment and the second embodiment are mixed. That is, subfields having the same discharge period in one field may be allocated to different blocks, and subfields having the same discharge period among the fields may be allocated to the blocks in different orders. In this case, even in the same bit data, the amount of emitted light that is visually sensed for each field or subfield is changed, thereby preventing the noise of the controller.

As described above, the method and apparatus for driving a plasma display panel according to the present invention divide a screen into two or more blocks and assign each subfield to a different block in one field in a different order or to each block within a field. By varying the value of the allocated subfield, scan bits and sustain pulses are driven differently for each subfield or block. As a result, the operating characteristics of the cell can be stabilized and the controller noise can be eliminated, and the number of discharges is emitted for each subfield or block, thereby compensating for the luminance difference between screens. In addition, the present invention can display images with different brightness for each subfield or for each block to obtain an even picture quality.

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 (8)

A method of driving a plasma display panel in which a screen is divided into at least two or more blocks, and one field is sequentially arranged into a plurality of subfields according to a luminance relative ratio to implement gradation. Sequentially outputting odd-numbered subfields to one of the plurality of blocks, and then sequentially outputting even-numbered subfields; And outputting odd-numbered subfields sequentially after outputting even-numbered subfields sequentially to other blocks of the plurality of blocks. The method of claim 1, And the subfields are sequentially assigned to the plurality of blocks in the order of luminance relative ratio. The method of claim 1, And after the subfields are sequentially assigned to the plurality of blocks, the subfields are sequentially assigned to the blocks in the reverse order of the assigned order. A driving apparatus of a plasma display panel in which one field is divided into a plurality of subfields according to a luminance relative ratio to implement gray scale, A driving unit driving the plasma display panel by dividing the plasma display panel into a plurality of blocks; The odd-numbered subfields are sequentially output to one of the plurality of blocks, and the even-numbered subfields are sequentially output, and the even-numbered subfields are sequentially output to the other blocks of the plurality of blocks. And a controller for controlling the driver to sequentially output subfields. delete delete The method of claim 4, wherein And the controller controls the driver to sequentially allocate subfields to the plurality of blocks in the order of the luminance relative ratio. The method of claim 4, wherein And the control unit controls the driving unit to sequentially allocate the subfields to the plurality of blocks after the subfields are sequentially assigned to the blocks in the reverse order of the allocated order.

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