KR20040072891A - Method and apparatus for driving plasma display panel - Google Patents

Abstract

PURPOSE: A method for driving a plasma display panel and an apparatus thereof are provided to improve display quality by compensating data generating contour noise. CONSTITUTION: According to the method for driving a plasma display panel, inputted moving picture data are compared with a stored noise data pattern. If the inputted moving picture data are equal to the stored noise data pattern, the inputted moving picture data are compensated and scattered. The stored noise data pattern is constituted with data patterns capable of generating contour noise. The step of compensating and scattering the inputted moving picture data is performed at every frame.

Description

Method and apparatus for driving plasma display panel {METHOD AND APPARATUS FOR DRIVING PLASMA DISPLAY PANEL}

The present invention relates to a plasma display panel, and more particularly, to a method and apparatus for driving a plasma display panel which can improve display quality.

Recently, there is a growing interest in flat panel displays that can reduce the weight and volume of cathode ray tubes. Such flat panel displays include liquid crystal displays, plasma display panels (PDPs), field emission displays, and electro-luminescence.

In such a flat panel display, a plasma display panel emits phosphors by 147 nm ultraviolet rays generated when a He + Xe, Ne + Xe or He + Ne + Xe gas is discharged to display images and moving images including characters or graphics. do. The plasma display panel is not only thin and large in size, but also recently, due to technology development, the plasma display panel provides greatly improved image quality.

In particular, the three-electrode AC surface discharge type plasma display panel accumulates wall charges using a dielectric layer during discharging, thereby lowering the voltage required for discharging, and has advantages of low voltage driving and long life because it protects the electrodes from sputtering of plasma.

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

Referring to FIG. 1, a discharge cell of a three-pole current alternating surface discharge type plasma display panel is formed on a scan electrode (Y) and a sustain electrode (Z) formed on an upper substrate (10), and a lower substrate (18). The address electrode X is provided.

Each of the scan electrode Y and the sustain electrode Z has a line width smaller than the line widths of the transparent electrodes 12Y and 12Z and the transparent electrodes 12Y and 12Z, and is formed on one side edge of the transparent electrode. 13Z). Indium tin oxide (ITO) is generally used as a material of the transparent electrodes 12Y and 12Z. As the material of the metal bus electrodes 13Y and 13Z, a metal such as chromium (Cr) is usually used. The metal bus electrodes 13Y and 13Z serve to reduce voltage drop caused by the transparent electrodes 12Y and 12Z having high resistance. An upper dielectric layer 14 and a passivation layer 16 are stacked on the upper substrate 10 on which the scan electrode Y and the sustain electrode Z are formed. In the upper dielectric layer 14, charged particles generated by gas discharge ionization gas (plasma) are accumulated. The protective layer 16 protects the upper dielectric layer 14 from sputtering of charged particles generated during gas discharge and increases the emission efficiency of secondary electrons. As the bottom film 16, magnesium oxide (MgO) is usually used. The address electrode X is formed in the direction crossing the scan electrode Y and the sustain electrode Z. The lower dielectric layer 22 and the partition wall 24 are formed on the lower substrate 18 on which the address electrode X is formed.

The phosphor layer 26 is formed on the surfaces of the lower dielectric layer 22 and the partition wall 24. The partition wall 24 is formed to be parallel to the address electrode X to physically distinguish the discharge cells, and prevent ultraviolet rays and visible light generated by the discharge from leaking to the adjacent discharge cells. The phosphor layer 26 is emitted by ultraviolet rays generated during gas discharge to generate visible light of any one of red (R), green (G), and blue (B). An inert mixed gas such as He + Xe, Ne + Xe, or He + Ne + Xe for discharging is injected into the discharge space provided between the upper and lower substrates 10 and 18 and the partition wall 24.

2 is a frame diagram illustrating a plasma display panel according to a conventional selective writing method.

Referring to FIG. 2, the conventional selective writing (SW) method is a wall charge remaining due to a reset period for initializing the full screen of the panel, an address period for selecting a cell, sustain and sustain discharge for maintaining the discharge of the selected cell. It is divided into an erasing period for erasing.

The three-electrode AC surface discharge type plasma display panel is driven by dividing one frame into several subfields having different emission counts in order to realize gray levels of an image. Each subfield is further divided into a reset period for generating discharge uniformly, an address period for selecting a Banggen cell, and a sustain period for implementing gray levels according to the number of discharges. When the image is to be displayed with 265 gray levels, the frame period (16.67 ms) corresponding to 1/60 second is divided into eight subfields SF1 to SF8. Each of the eight subfields SF1 to SF8 is divided into a reset period, an address period, and a sustain period. The reset period and the address period of each subfield are the same for each subfield, while the sustain period and the number of discharges thereof are 2 ⁿ in each subfield (where n = 0, 1, 2, 3, 4, 5, 6, 7) is increased in proportion. As such, gray scales can be implemented by a combination of subfields having different sustain periods.

The conventional selective write (SW) method initializes the full screen in the reset period and selects on cells that are turned on in the address period. Subsequently, in the sustain period, an image is displayed by sustaining discharge the on cells selected by the address discharge.

In the conventional selective write (SW) method, the pulse width of the scan pulse supplied to the scan electrode Y should be set to about 3 us or more so that sufficient wall charges are formed in the discharge cell by the address discharge. For this reason, in the selective write (SW) method, since the pulse width required for the address is long, the address period is relatively long, and thus the sustain period is difficult to secure.

On the other hand, in the plasma display panel, contour noise may be generated in a moving image because of the characteristic of realizing the gray level of the image by the combination of subfields. When the contour noise occurs, the contour appears on the screen, so the display quality of the screen is deteriorated.

In order to solve the problem of poor display quality in the selective writing (SW) method, the number of subfields may be increased by dividing a subfield of one frame. If a subframe is divided into ten or more subfields, the address period becomes longer as the number of subfields increases, making it difficult to secure time for the sustain period. In order to overcome this problem, there is a dual scan method for driving one screen by dividing, but when driving by dividing one screen, there is another problem that the manufacturing cost is increased because the driving drive ICs have to be added as much.

3 is a frame configuration diagram of a plasma display panel according to a conventional selective erasing method.

Referring to FIG. 3, the conventional selective erasure (SE) method is divided into a reset period for initializing the full screen of the panel, an address period for selecting a cell, and a sustain period for maintaining the discharge of the selected cell.

This conventional selective erasing (SE) method turns off the discharge cells selected in the address period after turning on the full screen by turning on the full screen in the reset period of all subfields in one frame. Subsequently, in the sustain period, images are displayed by sustaining discharge only discharge cells not selected by the address discharge.

However, the conventional selective erasing (SE) method has a disadvantage in that the contrast ratio is low because the full screen is turned on in the entire writing period, which is a non-display period for each subfield. The selective erase (SE) driving method is not used well because the screen is bright as the sustain period is sufficiently secured and the contrast ratio is bad, and the screen is not clear and the image is blurred.

4 is a graph showing a change in the light emitting center point with respect to an input gray scale value according to a conventional selective writing (SW) method.

Referring to FIG. 4, in the conventional method of driving a plasma display panel according to a selective writing (SW) method, the emission center point changes according to a change in an input gray level. As the gray level increases, the position value of the emission center point also increases, but at a specific input gray level, the bladder center point changes greatly with the increase of the input gray level "1" (for example, 31 → 32, 63 → 64, 127 → 128). ). Contour noise occurs due to data in which the emission center point changes rapidly with respect to the input gray level, thereby degrading display quality.

5A to 5F are diagrams illustrating light emission center points in a frame structure according to a conventional selective writing (SW) method.

5A to 5F, when the input gray level is “127” as shown in FIG. 5A, the first to seventh subfields having the luminance weight of “1, 2, 4, 8, 16, 32, 64” are turned on. (On), and the eighth subfield in which the luminance weight is "128" is off. On the other hand, when the input gray level is " 128 " as shown in Fig. 5B, the first to seventh subfields having luminance weights of " 1, 2, 4, 8, 16, 32, 64 " The eighth subfield having the weight "128" is turned on. As the input gray level increases from 127 to 128, the emission center point changes drastically.

When the input gray level is “63” as shown in FIG. 5C, the first to sixth subfields having luminance weights of “1, 2, 4, 8, 16, 32” are turned on, and the luminance weight is “64”. , 7th and 8th subfields of "128" are Off. Meanwhile, when the input gray level is “64” as shown in FIG. 5D, the first to sixth subfields and the eighth subfield having luminance weights of “1, 2, 4, 8, 16, 32, 128” are turned off. ), And the seventh subfield in which the luminance weight is "64" is turned on. As the input gray level increases from 63 to 64, the emission center point changes drastically.

When the input gray level is "31" as shown in FIG. 5E, the first to fifth subfields having luminance weights of "1, 2, 4, 8, and 16" are turned on, and the luminance weights are "32, 64". , 6th through 8th subfields of 128 "are Off. On the other hand, when the input gray level is "32" as shown in FIG. 5F, the first to fifth subfields and the seventh and eighth subfields having the luminance weights of "1, 2, 4, 8, 16, 64, 128" The sixth subfield, which is Off and the luminance weight is "32", is On. As the input gray level increases from 31 to 32, the emission center point changes drastically.

As described above, the driving method of the plasma display panel according to the conventional selective writing (SW) method generates a contour noise by rapidly changing the center of emission at a specific input gray level. As a result, there is a problem that the display quality is degraded.

Therefore, there is a need for a method and apparatus for driving a plasma display panel capable of improving display quality.

Accordingly, an object of the present invention is to provide a method and apparatus for driving a plasma display panel that can improve display quality.

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

2 is a frame diagram illustrating a plasma display panel according to a conventional selective writing method.

3 is a frame configuration diagram of a plasma display panel according to a conventional selective erasing method.

4 is a graph showing a change in the light emitting center point with respect to an input gray scale value according to a conventional selective writing (SW) method.

5A to 5F are diagrams illustrating light emission center points in a frame structure according to a conventional selective writing (SW) method.

6 is a diagram illustrating a method of driving a plasma display panel according to a first embodiment of the present invention.

7 is a diagram illustrating a method of driving a plasma display panel according to a second embodiment of the present invention.

8 is a diagram illustrating a method of driving a plasma display panel according to a third embodiment of the present invention.

9 is a configuration diagram illustrating a driving device of a plasma display panel according to the present invention.

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

10: upper substrate 18: lower substrate

Y: scan electrode Z: sustain electrode (Z)

X: address electrode (X) 12Y, 12Z: transparent electrode

13Y, 13Z: metal bus electrode 14: upper dielectric layer

16: protective film 22: lower dielectric layer

24: partition 26: phosphor layer

41: Gamma Compensation Government 42: Automatic Gain Control

43: error diffusion unit 44: subfield mapping unit

45: frame memory 46: data alignment unit by drive IC

47: timing controller 48: data driver

51: scan driver 52: sustain driver

53: data search and correction unit 54: data pattern memory

In order to achieve the above object, a driving method of a plasma display panel according to the present invention includes comparing input moving image data with a stored noise data pattern, and when the input moving image data is the same as the stored noise data pattern, And correcting and distributing the generated moving image data.

The stored noise data pattern may be configured of data patterns capable of generating contour noise.

Correcting and distributing the input moving image data is performed every frame.

The correction of the input moving image data is performed by inverting at least one or more subfield states among a plurality of subfields constituting one frame.

The correction of the moving image data is characterized by converting a subfield having a luminance weight value of "4" or less.

The method for distributing the input moving image data, characterized in that the supply position of the moving image data is converted in a pixel block including a pixel to which the moving image data is supplied.

The apparatus for driving a plasma display panel according to the present invention includes a plurality of subs including a reset period for initializing a cell of a plasma display panel using gas discharge, an address period for selecting a cell, and a sustain period for causing sustain discharge of the selected cell. A driving apparatus of a plasma display panel which displays moving images using fields, comprising: a data pattern memory for storing noise data pantones compared with input moving image data, and searching whether the input moving image data matches the noise data pattern And a data retrieval and correction unit for converting the input moving image data when the input moving image data coincides with the noise data pattern, and for mapping the moving image data converted from the data retrieval and correction unit to a subfield. And field mapping unit, in accordance with data from the subfield mapping unit is characterized in that it comprises a panel driver for driving the panel.

The noise data pattern memory may store data patterns capable of generating contour noise.

The data search and correction unit may convert pixels to which the converted moving image data are input.

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

Hereinafter, a driving method and apparatus of a plasma display panel according to the present invention will be described in detail with reference to FIGS. 6 to 9.

6 to 8 illustrate a method of driving a plasma display panel according to an exemplary embodiment of the present invention.

In the method of driving a plasma display panel according to an exemplary embodiment of the present invention, one frame is divided into a plurality of subfields. The first to eighth subfields are subfields using a selective writing (SW) method, and thus, 256 gray levels can be implemented by a combination thereof.

The first to eighth subfields are a reset period for initializing discharge cells, an address period for selecting discharge cells, and a sustain period for discharging in the discharge cells selected in the address period before the address period by a selective write (SW) method. It includes. The reset and address periods are the same for each subfield, while the sustain period and the number of discharges thereof are increased at a rate of 2 ⁿ (n = 0, 1, 2, 3, 4, 5, 6, 7).

When a moving image is displayed on the plasma display panel, contour noise is generated when data whose emission center point is rapidly changed according to input gray levels is input to adjacent pixels (for example, A, B, C, and D).

Referring to FIG. 6, the driving method of the plasma display panel according to the first exemplary embodiment of the present invention searches for input gray level data in order to reduce contour noise. When data values whose emission center points are rapidly changed among the input gray levels are input, the input data values are converted, the state of the third subfield having the luminance weight of "4" is inverted, and the pixel position to which the corrected data is supplied. Convert to frame units. For example, the pixel position supplied with the corrected data is rotated clockwise in units of frames.

Convert the data by rotating the pixels. The gray level is expressed by this converted data to reduce contour noise.

In the Nth Frame period, data of the input gray level "127" is input to the A and C pixels, and data of the input gray level "128" is input to the B and D pixels.

Converts data to be input for A, B, C, and D pixels in the N + 1th frame period. By converting the pixels and inverting the state of the third subfield having a luminance weight of "4", data of the input gray level "123" is input to the A and C pixels, and input gray level "132 to the B and D pixels. Data is input.

Converts data to be input for A, B, C, and D pixels in the N + 2th frame period. By converting the pixels and inverting the state of the third subfield having a luminance weight of "4", data of the input gray level "127" is input to the A and C pixels, and input gray level "128 to the B and D pixels. Data is input.

The data to be input of A, B, C, and D pixels is converted in the N + 3th period. By converting the pixels and inverting the state of the third subfield having a luminance weight of "4", data of the input gray level "123" is input to the A and C pixels, and input gray level "132 to the B and D pixels. Data is input. Through the above-described method, input gray level data in which the emission center point changes rapidly is spatially and spatially dispersed.

Referring to FIG. 7, the driving method of the plasma display panel according to the second exemplary embodiment of the present invention searches for input gray level data in order to reduce contour noise. When data values whose emission center points are rapidly changed among the input gray levels are input, the input data values are converted, the state of the second subfield having a luminance weight of "2" is inverted, and the pixel position to which the corrected data is supplied. Convert to frame units. For example, rotate clockwise. The gray level is expressed by this converted data to reduce contour noise.

In the Nth Frame period, data of the input gray level "63" is input to the A and C pixels, and data of the input gray level "64" is input to the B and D pixels.

Converts data to be input for A, B, C, and D pixels in the N + 1th frame period. The pixels of the input gray level " 61 " are inputted to the A and C pixels, and the input gray level " 66 " Data is input.

Converts data to be input for A, B, C, and D pixels in the N + 2th frame period. By converting the pixels and inverting the state of the second subfield having a luminance weight of "2", data of the input gray level "63" is input to the A and C pixels, and input gray level "64 to the B and D pixels. Data is input.

The data to be input of A, B, C, and D pixels is converted in the N + 3th period. The pixels of the input gray level " 61 " are inputted to the A and C pixels, and the input gray level " 66 " Data is input. Through the above-described method, input gray level data in which the emission center point changes rapidly is spatially and spatially dispersed.

Referring to FIG. 8, the driving method of the plasma display panel according to the third embodiment of the present invention searches for input gray level data in order to reduce contour noise. When data values whose emission center points change rapidly among the input gray levels are input, the input data values are converted, the state of the first subfield having the luminance weight of "1" is inverted, and the pixel position to which the corrected data is supplied. Convert to frame units. For example, rotate clockwise. The gray level is expressed by this converted data to reduce contour noise.

In the Nth Frame period, data of the input gray level "31" is input to the A and C pixels, and data of the input gray level "32" is input to the B and D pixels.

Converts data to be input for A, B, C, and D pixels in the N + 1th frame period. By converting the pixels and inverting the state of the first subfield having a luminance weight of "1", data of input gray level "30" is input to pixels A and C, and input gray level "33 to pixels B and D. Data is input.

Converts data to be input for A, B, C, and D pixels in the N + 2th frame period. By converting the pixels and inverting the state of the first subfield having a luminance weight of "1", data of the input gray level "31" is input to the A and C pixels, and input gray level "32 to the B and D pixels. Data is input.

The data to be input of A, B, C, and D pixels is converted in the N + 3th period. By converting the pixels and inverting the state of the first subfield having a luminance weight of "1", data of input gray level "30" is input to pixels A and C, and input gray level "33 to pixels B and D. Data is input. Through the above-described method, input gray level data in which the emission center point changes rapidly is spatially and spatially dispersed.

The driving method of the plasma display panel according to the present invention can reduce contour noise in the entire frame by not generating contour noise in the N + 1 th frame and the N + 3 th frame.

FIG. 9 is a configuration diagram illustrating a driving apparatus of a plasma display panel according to an exemplary embodiment of the present invention, and illustrates a driving apparatus of a plasma display panel that senses data about an input gray level and corrects the sensed data.

Referring to FIG. 9, a plasma display panel driving apparatus according to the present invention includes a data driver 48 for driving an address electrode X of a plasma display panel and a scan for driving a scan electrode Y of a plasma display panel. And a sustain controller 51, a timing controller 47 for controlling the driving timing of the plasma display panel, an automatic gain controller 42 connected between the gamma corrector 41 and the data driver 48, The error diffusion unit 43, the data retrieval unit 53, the data pattern memory 54, the subfield mapping unit 44, the frame memory 45, and the drive IC data alignment unit 46 Equipped.

The data driver 48 includes a plurality of data drive ICs connected to a predetermined number of address electrodes X to supply data to the address electrodes X, respectively.

The scan driver 51 is connected to the scan electrodes Y to supply a reset pulse (or setup pulse) to the scan electrodes Y at the same time. In addition, the scan driver 51 sequentially supplies the scan pulses to the scan electrodes Y in the address period, and then simultaneously supplies the sustain pulses to the scan electrodes Y in the sustain period.

The sustain driver 52 is commonly connected to the sustain electrodes Z to supply the sustain pulses to the sustain electrodes Z at the same time.

The timing controller 47 receives the vertical / horizontal synchronization signals H and V to generate a timing control signal, and the timing controller 47 outputs the timing control signal to the data alignment unit 46, the data driver 49, the scan driver 51, The driving timing of the plasma display panel is controlled by supplying it to the sustain driver 52.

The gamma correction unit 41 gamma-corrects the moving image signal to linearly change the luminance value according to the gray value of the moving image signal.

The automatic gain adjusting unit 42 converts the gradation range of the input data R, G, and B into a preset gradation range according to the luminance information from the gamma correction unit 41 to uniformly compensate the gain of the input data. It will play a role.

The error diffusion unit 43 serves to finely adjust the luminance value by diffusing the error component to adjacent cells. To this end, the error diffusion unit 43 separates the data into the integer and the fractional part and multiplies the fractional part by a Fly-Steinberg coefficient to spread the error to adjacent cells.

The data retrieval and correction unit 53 compares the data input from the error diffusion unit 43 with the data patterns stored in the data pattern memory 54 and stores the received data pattern in the data pattern memory 54. When the data patterns match the data patterns, the data is corrected and transmitted to the frame memory 45.

The data pattern memory 54 stores a pattern of data capable of generating contour noise so that data input to the data search and correction unit 53 can be compared.

The subfield mapping unit 44 maps data of one frame received from the data correction unit 54 to the subfields, respectively. The data mapped for each subfield is assigned the lowest bit to the subfield in which the minimum luminance weight is set and the most significant bit to the subfield in which the maximum luminance weight is set.

The frame memory 45 stores data from the subfield mapping unit 44 in units of frames. The drive-specific IC data sorter 46 rearranges the data input from the frame memory 45 corresponding to each data drive IC and supplies the data to the data driver 48.

The method and apparatus for driving a plasma display panel according to the present invention searches for data input to pixels adjacent to each other and corrects such data when the data has a sharp change in the emission center point to generate contour noise. By transforming pixels that can change and generate contour noise, input gray level data whose emission center points change rapidly are spatially and spatially distributed.

As described above, the method and apparatus for driving a plasma display panel according to the present invention do not generate contour noise in the N + i-th (i = positive integer odd number) frames, so that the contour noise in the entire frame is reduced. noise) can be reduced.

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 (9)

Comparing the input moving image data with a stored noise data pattern; And correcting and distributing the input moving image data when the input moving image data is the same as the stored noise data pattern. The method of claim 1, And the stored noise data pattern comprises data patterns capable of generating contour noise. The method of claim 1, And correcting and distributing the input moving image data are performed every frame. The method of claim 3, wherein And correcting the input moving image data by inverting a state of at least one or more subfields among a plurality of subfields constituting one frame. The method of claim 4, wherein And the correction of the moving image data converts a subfield having a luminance weight value of "4" or less. The method of claim 3, wherein In the method for distributing the input video data, And a supply position of the moving image data in a pixel block including a pixel to which the moving image data is to be supplied. A plasma display panel displaying a moving image using a plurality of subfields including a reset period for initializing a cell of a plasma display panel using gas discharge, an address period for selecting a cell, and a sustain period for causing sustain discharge of the selected cell. In the drive device of, A data pattern memory for storing noise data patterns to be compared with input moving image data; Search whether the input video data matches the noise data pattern, A data search and correction unit for converting the input moving image data when the input moving image data matches the noise data pattern; A subfield mapping unit for mapping the moving image data converted from the data retrieval and correction unit to subfields; And a panel driver for driving the panel in accordance with data from the subfield mapping unit. The method of claim 7, wherein And the noise data pattern memory stores data patterns capable of generating contour noise. The method of claim 7, wherein And the data search and correction unit converts the pixels to which the converted moving image data are input.