KR100293525B1 - Method For Driving Plasma Display Panel Of High Frequency And Apparatus Thereof - Google Patents

Abstract

The present invention relates to a method and apparatus for driving a plasma display panel using a high frequency that can prevent the occurrence of contour noise.

A method of driving a high frequency plasma display panel according to the present invention includes: a high frequency triggering step of causing a high frequency discharge to be simultaneously started across any scan line of the panel; And selectively erasing the high frequency discharge by sequentially scanning the corresponding line where the high frequency discharge is started and selectively supplying erase pulses so as to correspond to the brightness level of the image signal.

According to the present invention, since gray scales are displayed while scanning the scan lines sequentially, contour noise does not occur, and the circuit configuration is simplified since only the analog signals are sampled and only a driving signal corresponding to the level of the sampled image signal is supplied. do.

Description

Method and device for driving high frequency plasma display panel {Method For Driving Plasma Display Panel Of High Frequency And Apparatus Thereof}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display apparatus, and more particularly, to a method and apparatus for driving a high frequency plasma display panel capable of preventing contour noise.

Recently, research on plasma display panels (hereinafter referred to as PDPs), which are easy to manufacture panels as large-area flat panel displays, has been actively conducted according to the needs of large flat panel displays. The PDP generally uses a gas discharge phenomenon to display an image using visible light generated by vacuum ultraviolet rays generated during gas discharge to emit phosphors.

Referring to FIG. 1, a structure of a discharge cell configured in a PDP of a three-electrode alternating current (AC) surface discharge method which is commonly used is shown.

In the discharge cell 28 of the PDP shown in FIG. 1, an upper substrate 10 and a lower substrate 12, which are display surfaces of an image, are arranged in parallel by partitions not shown, and a sustain electrode on the upper substrate 10 is provided. A pair, that is, the scan / sustain electrode 14 and the sustain electrode 16 are formed side by side with an upper dielectric layer 18 and a protective layer 20 applied thereon. The address electrode 22 is formed on the lower substrate 12 in a direction perpendicular to the sustain electrode pairs 14 and 16, and the lower dielectric layer 24 and the fluorescent layer 26 are sequentially applied thereon. The discharge gas is injected into the discharge space 21 provided by the partition wall.

The discharge cell 28 having such a configuration is selected by the address discharge between the address electrode 22 and the scan / sustain electrode 16, and then the vacuum ultraviolet rays generated by the continuous sustain discharge between the sustain electrodes 14 and 16 are discharged. The fluorescent material 26 emits visible light. In this case, by adjusting the sustain discharge period, that is, the number of sustain discharges, a gray scale necessary for displaying an image is realized. Accordingly, the number of sustain discharges is an important factor in determining the brightness and discharge efficiency of the PDP. For this sustain discharge, step pulses having a frequency of about 200 to 300 kHz, a pulse width of about 10 to 20 Hz, and a duty ratio of 1 are periodically applied to the sustain electrodes 14 and 16. In this case, the sustain discharge occurs only once at an extremely short instant per sustain pulse. The charged particles generated by the sustain discharge move the discharge paths formed between the sustain electrodes according to the polarities of the electrodes, so that wall charges are formed in the discharge space of the cell, and the discharge voltage in the discharge space decreases due to the wall charges. Will stop. As described above, the sustain discharge by the existing sustain pulse is generated only once at a short time per pulse, and most of the other time is consumed in the preparation of the wall charge and the next discharge, so that the discharge efficiency of the PDP is inevitably low.

Recently, in order to solve the low discharge efficiency problem of the PDP, a method of using a high frequency discharge using a high frequency signal as a display discharge has recently emerged. High frequency discharge is usually generated by high frequency signals in the range of tens of MHz to hundreds of MHz. As the electron vibrates by vibrating electric field, it causes continuous ionization and excitation of discharge gas. It is possible to cause continuous discharge. The high frequency discharge has a physical effect such as a positive column having a very high discharge efficiency when the distance between the electrodes is long in the glow discharge. Accordingly, there is an advantage that can significantly improve the discharge efficiency of the PDP when using a high frequency discharge.

Referring to FIG. 2, there is shown a perspective view showing a discharge cell configured in a PDP using a high frequency wave.

The PDP discharge cell shown in FIG. 2 includes a high frequency electrode 50 disposed on the upper substrate 40, an address electrode 44 and a scanning electrode 46 disposed on the lower substrate 42. The upper substrate 40 and the lower substrate 42 are spaced apart from each other in parallel, and the address electrode 44 in the vertical direction and the scan electrode 46 in the horizontal direction are formed on the lower substrate 42. A dielectric layer 48 is formed between the address electrode 44 and the scan electrode 46. The upper substrate 50 is provided with a high frequency electrode 50 to which a high frequency voltage is applied in the same direction as the scan electrode 46. Between the upper substrate 40 and the lower substrate 42, barrier ribs for eliminating optical interference between adjacent discharge cells are formed in a block-shaped structure. On the surface of the upper plate 40 and the partition wall 52 on which the high frequency electrode 50 is formed, a phosphor 54 for generating visible light of red, green, or blue is coated. Then, the discharge gas is filled in the discharge space therein. In the discharge cell, when the scan voltage is supplied to the scan electrode 46 and the data voltage is supplied to the address electrode 44, the charged particles are generated by address discharge by the voltage difference. Subsequently, the charged particles continuously ionize and excite the discharge gas while vibrating by the high frequency voltage supplied to the high frequency electrode 50, and emits vacuum ultraviolet rays while the excited gas atoms and molecules transition to the ground state. Visible light is emitted by emitting phosphors.

FIG. 3 shows the overall electrode arrangement structure of the PDP constituting the discharge cell shown in FIG.

The PDP shown in FIG. 3 includes address electrode lines X1 to Xm arranged corresponding to each column line, and scan electrode lines Y1 arranged side by side corresponding to each row line. Yn) and high frequency electrode lines RF. The discharge cells 34 are provided at the intersections of the address electrode lines X1 to Xm, the scan electrode lines Y1 to Yn, and the high frequency electrode lines RF.

The high frequency PDP is usually driven by an ADS (Address and Display Separation) driving method. The ADS driving method is a method of driving a PDP by separating an address period and a display period, that is, a high frequency discharge period. In this case, one frame is divided into eight subfields corresponding to each bit of 8-bit video data, and each subfield is further divided into an address period and a display period. Here, the address period of each subfield is the same and 1: 2: 4: 8:... The gray scale is represented by a combination of display periods by giving a weight of: 128 ratio. The display order of the subfield periods corresponding to each bit is also in the order of SF1, SF2, SF3, SF4, SF5, SF6, SF7, SF8. As such, since the PDP displays images by superimposing the light emitted by the discharge time modulation method, the contour noise is generated due to a mismatch between the integration direction of the light assumed in the driving method and the visual characteristics recognized by the human eye. have. Contour noise is usually observed between white and black bands between frames, and occurs when levels with very different periods between emission patterns are displayed continuously, for example, between levels 127-128, 63-64, 31-32. It is becoming. Here, when the frame displaying 127 and the frame displaying 128 are adjacent to each other, the frame displaying 127 emits light during the second to seventh subfields. Subsequently, in the next frame displaying 128, it is turned off during the first to seventh subfield periods, and then emits light only in the eighth subfield corresponding to 128. In this way, black bands are observed between the two frames as the light emission patterns become longer due to the first to seventh subfield periods that are turned off even though the brightness level difference between the frames is not large. In addition, bright bands are observed between the two frames varying from 128 to 127 due to the same cause. Such contour noise usually occurs most frequently when the chromosome moves. In particular, when displaying a color image, the contour noise may cause a problem in that the image is deteriorated due to unbalanced colors.

For this reason, the PDP driving apparatus minimizes the contour noise by rearranging the display order of the subfields so as not to have a large light emission pattern or rearranging the eighth subfield period corresponding to 128 by splitting them into 64-64. . However, since this requires a rearrangement process using a complicated memory circuit, the configuration of the data driving circuit is complicated.

FIG. 4 is a block diagram showing a conventional PDP data driving device. The data driving device of FIG. 4 is an analog-to-digital converter (hereinafter referred to as 'A-D') converter 60 for sampling an input analog video signal. ), A multiplexer 62 for converting the sampling signal input from the AD converter 60 into 8-bit video data, a frame memory 64 for temporarily storing the video data input from the multiplexer 62, and a frame memory. From the memory controller 65 for rearranging and outputting the image data of 64, the demultiplexer 66 for separating and outputting the image data output from the memory controller 65 by the same bit, and from the demultiplexer 66. And a data driver 68 for outputting a driving pulse according to the input image data to the PDP 70.

In the high frequency PDP data driving apparatus shown in FIG. 4, the A-D converter 60 samples and outputs an input analog video signal. The multiplexer 62 converts the sampling signal input from the A-D converter 60 into 8-bit image data and outputs it. The frame memory 64 temporarily stores image data input from the multiplexer 62. In this case, the frame memory 64 has a capacity for storing video data of one frame. The memory controller 65 rearranges and outputs image data output from the frame memory 64. When the subfields need to be divided and rearranged to minimize the contour noise, a memory controller 65 having a complicated circuit configuration is required. The demultiplexer 66 separates and outputs image data input from the memory controller 65 for each bit. In this case, the image data output from the memory controller 65 is continuous with single bits corresponding to the same subfield. For example, when the PDP 70 is driven during the lowest subfield period having the smallest weight, the video signal supplied to the data driver 68 is continuous with pixel data of least significant bit (LSB). The data driver 68 drives the address electrode lines on the PDP 70 by the pixel data input from the demultiplexer 66.

As such, the conventional PDP data driving circuit becomes complicated to minimize the contour noise.

Accordingly, an object of the present invention is to provide a method and apparatus for driving a high frequency PDP which can eliminate the problem of the contour noise by removing the cause of the contour noise in advance by causing the gray scale to be displayed while scanning sequentially.

Another object of the present invention is to provide a high frequency PDP driving method and apparatus which can simplify the configuration of a data driving circuit.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing a discharge cell formed in a conventional three-electrode alternating current surface discharge plasma display panel.

2 is a perspective view showing a discharge cell formed in a conventional high frequency plasma display panel.

FIG. 3 is an overall electrode layout view of a plasma display panel including the discharge cells shown in FIG. 2.

4 is a block diagram showing a conventional high frequency plasma display panel driving apparatus.

5 is a view showing a high frequency plasma display panel driving method according to the present invention.

FIG. 6 is a waveform diagram showing details of a driving signal supplied during one horizontal scanning period in FIG. 5; FIG.

FIG. 7 is a waveform diagram showing a supply form of erase pulses shown in FIG. 6; FIG.

8 is a driving waveform diagram illustrating a method of driving a high frequency plasma display panel according to an exemplary embodiment of the present invention.

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

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

10, 40: upper substrate 12, 42: lower substrate

14, 46: scanning electrode 16: sustaining electrode

18, 48: dielectric layer 20: protective layer

22, 44: address electrodes 26, 54: phosphor

21: discharge space 28, 34: discharge cell

50: high frequency electrode 52: partition wall

60, 72: A-D converter 62: multiplexer

64: frame memory 65: memory controller

66: demultiplexer 68, 78: data driver

70, 80: PDP 74: Line memory

76: controller

In order to achieve the above objects, the high frequency PDP driving method according to the present invention comprises the steps of: a high frequency triggering so that a high frequency discharge is initiated simultaneously across all the scanning lines of the panel; And selectively erasing the high frequency discharge by sequentially scanning the corresponding line where the high frequency discharge is started and selectively supplying erase pulses so as to correspond to the brightness level of the image signal.

The high frequency PDP driving apparatus according to the present invention includes a sampling means for sampling an input analog video signal, a storage means for temporarily storing the sampled video signal in units of scan lines, and reading the stored sampling video signal and rearranging the same according to the luminance level. And control means for generating a drive signal having a time difference according to the luminance level, and a data drive for supplying a reset signal for starting a high frequency discharge every horizontal period and an erase signal according to the drive signal to the data electrode lines of the panel. A means is provided.

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

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 5 to 9.

5 shows a high frequency PDP driving method according to the present invention.

In FIG. 5, the high frequency PDP driving method according to the present invention implements gradation by a sequential scanning method in the same manner as a conventional cathode ray tube (CRT) driving method. In other words, the scan signals SS1 to SSn are sequentially supplied to the n scan electrode lines Y1 to Yn as shown in FIG. 3 to select the scan electrode lines Y1 to Yn, and the selected time. The gray level is realized by varying the supply point of the data signal according to the luminance level. In this case, gradation is realized by turning on all the discharge cells of the corresponding line at the start of one horizontal period and then changing the supply time of the erase pulse according to the luminance level. This is possible because the high frequency PDP has a significantly higher discharge efficiency than the existing low frequency AC PDP.

Referring to FIG. 6, a driving waveform supplied to display 256 gray scales during a period in which a scanning signal of one horizontal period 1H is supplied to the i-th scan electrode line is shown.

In FIG. 6, before the gray level is implemented in the selected scan line, high frequency discharge is started in all the discharge cells included in the scan line, and then the gray scale is realized by changing the application time of the erase pulse according to the luminance level. Able to know. To this end, a high frequency signal RFS is commonly supplied to the high frequency electrode line, and reset and erase signals RES0 to RES255 are supplied to the data electrode lines X1 to Xm. In detail, a scan signal (not shown) is supplied to the i-th scan electrode line, and a reset pulse RP synchronized with the scan signal is simultaneously supplied to the data electrode lines X1 to Xm, thereby providing the i-th scan line. The high frequency discharge is started in the discharge cells. Subsequently, the erase pulses EP are sequentially supplied to the data electrode lines X1 to Xm in order of luminance level. Accordingly, when all 256 gray levels are to be displayed during one horizontal (1H) period, 256 erase pulses EP are required. The erase pulse EP0 is applied directly to the discharge cells corresponding to the 'O' level having the lowest luminance level at the start of one horizontal period 1H. In the discharge cells to which the erase pulse EP1 is applied, the high frequency discharge is erased to display an 'O' level. Subsequently, a high frequency discharge in the discharge cells is applied by applying the erase pulse EP1 shifted by one step rather than the erase pulse EP1 for displaying the '0' level to the discharge cells corresponding to the '1' luminance level. To be stopped. The erase pulses are sequentially applied according to the magnitude of the luminance level, and the erase pulses EP255 are applied or erased to the discharge cells corresponding to the '255' level having the highest luminance level at the end of one horizontal period (1H). By not applying a pulse, the '255' level is displayed. Then, the i + 1 th scan electrode line is selected to implement gradation in the above-described method. In this way, by applying a reset pulse synchronized with the scan pulse to the data electrode lines (X1 to Xm) of the scan electrode line to start a high frequency discharge at the same time, and then to the luminance level to be displayed for one horizontal period (1H) The grayscale can be displayed while scanning by supplying the erase pulses EP0 to EP255 according to the control. In this case, the erase pulses EP0 to EP255 are naturally applied in descending order of luminance level. Here, the method for determining the width of the erase pulses EP0 to EP255 is as follows.

In general, when the image is displayed in VGA resolution, the width of the erase pulse EP is calculated as follows. In the PDP having 480 scan lines in one frame of 16.67 ms, gray scales are implemented by the above-described method, and thus the width of the erase pulse (EP) is 16.67 ms / 26,880. It should be less than = 130ns. However, it is difficult to set the width of the erase pulse EP to 130 ns or less, but it can be solved by applying the temporally adjacent erase pulses EPn and EPn + 1 as shown in FIG. 7. In FIG. 7, it can be seen that the width b of the nth erase pulse EPn and the n + 1th erase pulse EPn + 1 is set to be the same to supply a portion of the erase pulse EPn. In other words, when the grayscale is displayed using the erasing pulse EP, the grayscale is displayed only for one scan line, so that the nth erasing pulse EPn and the n + 1th erasing pulse EPn + 1 Since only the time difference for gray scale display between rising edges is required, two erase pulses EPn and EPn + 1 can be supplied in an overlapping manner. In this case, the time difference a between the nth erase pulse EPn and the rising edge of the n + 1th erase pulse EPn + 1 only needs to be set to 130 ns or less. As a result, there is an advantage that the width of the erase pulse EP can be set more freely.

8 illustrates a driving waveform applied to a high frequency PDP driving method according to an embodiment of the present invention.

In FIG. 8, the high frequency signal RF is commonly supplied to the high frequency electrode line RF, and the scan signals SS1, SS2, SS3,... Are supplied to the scan electrode lines Y1, Y2, Y3,. The reset and erase signals RES are supplied to the data electrode lines X1 to Xm. The scan signal SS1 is supplied to the first scan electrode line Y1, and the reset pulse RP is simultaneously supplied to the m address electrode lines X1 to Xm in synchronization with the scan signal SS1. Accordingly, discharge occurs in all the discharge cells of the first scan line to start high frequency discharge. Then, the gray level is displayed by selectively stopping the high frequency discharge by supplying the erase pulses EP0 to EP255 corresponding to the driving time point to the address electrode lines X1 to Xm for one horizontal (1H) period according to the luminance level. . Subsequently, the gradation is implemented using the selective erasing method while sequentially applying the scan signal to the next scan electrode lines Y2, Y3, Y4, .... In this way, the scan lines are sequentially selected and high frequency discharge is simultaneously started in all discharge cells included in the selected scan line, and then erase pulses are selectively applied according to the luminance level to selectively stop the high frequency discharge. It can be implemented. As a result, the high frequency PDP driving method of the present invention displays gray levels while sequentially scanning lines, so that contour noise generated in the conventional PDP driving method is not generated. In addition, since the gray level is implemented by a selective erase method using a short reset pulse and an erase pulse without requiring an additional address time, the discharge efficiency can be increased by increasing the high frequency discharge time by an unnecessary address time. In addition, since the scan signals supplied to the scan electrode lines are not supplied over one horizontal period as in the prior art and have a short width as the reset pulse, power consumption can be reduced.

FIG. 9 is a block diagram illustrating a high frequency PDP data driving apparatus according to an embodiment of the present invention. The data driving apparatus of FIG. 9 is an analog-to-digital converter (hereinafter, referred to as 'A-D') converter for sampling an input analog video signal. 72, the line memory 74 for temporarily storing the sampling video signal input from the AD converter 72 in scanning line units, and the sampling video signal stored in the line memory 74 are rearranged in accordance with the brightness level to obtain a luminance level. A controller 76 for generating a drive signal having a time difference and a data driver 78 for supplying an erase signal according to the drive signal input from the controller 76 to address electrode lines on the PDP 80. Equipped.

In the high frequency PDP data driving circuit shown in FIG. 9, the A-D converter 72 samples and outputs an input analog video signal. The line memory 74 temporarily stores the sampling video signal input from the A-D converter 72. In this case, the line memory 74 has a capacity for storing video signals for one scan line. The controller 76 rearranges the image signals of one scan line stored in the line memory 74 in the order of the luminance levels, and generates a drive signal having a time difference in accordance with the luminance levels. In this case, the drive signal output from the controller 76 is output in the order of the drive signal of the discharge cell having a low luminance level from the drive signal of the discharge cell having a low luminance level. The data driver 78 drives the address electrode lines on the PDP 80 by generating an erase signal EP according to a drive signal input from the controller 76 together with a reset pulse for starting a high frequency discharge every horizontal period. .

As a result, the conventional high frequency PDP driving device requires a complicated memory design to reduce the contour noise and a circuit for converting an image signal into an 8-bit subfield signal, whereas the PDP driving device according to the present invention merely converts an analog signal. The circuit configuration can be simplified because only the driving signal corresponding to the sampled and sampled video signal level is supplied.

As described above, according to the high frequency PDP driving method according to the present invention, since the gray scale is displayed by using the selective erasing method while scanning the scanning lines sequentially, the contour noise generated in the conventional PDP driving method is not generated. In addition, according to the high frequency PDP driving method according to the present invention, grayscales are displayed by a short reset pulse and an erase pulse according to the luminance level without requiring an additional address time, thereby increasing discharge efficiency by increasing the high frequency discharge time by an unnecessary address time. It becomes possible. In addition, according to the high frequency PDP driving method according to the present invention, since the scan signals supplied to the scan electrode lines are not supplied over one horizontal period as in the related art, and have a short width as the reset pulse, power consumption can be reduced. Will be. In addition, the high frequency PDP driving method according to the present invention has an advantage in that the width of the erase pulse can be set more freely by supplying the erase pulses so as to overlap each other. Furthermore, the high-frequency PDP driving apparatus according to the present invention is not only simple in circuit configuration but also in memory capacity because it only needs to sample the analog signal and supply the driving signal according to the level of the sampled video signal in contrast to the conventional complicated circuit configuration. This can reduce the cost.

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)

In a driving method of a plasma display panel using a high frequency discharge, A high frequency triggering step of causing a high frequency discharge to be simultaneously started across any scan line of the panel; And selectively erasing the high frequency discharge by sequentially scanning the corresponding line on which the high frequency discharge is started and selectively supplying erase pulses so as to correspond to the brightness level of the image signal. The method of claim 1, The high frequency discharge is initiated by a high frequency voltage supplied to the high frequency electrode of the panel and a reset signal simultaneously supplied to the data electrodes of the corresponding line. The method of claim 2, And the reset signal is supplied in synchronization with a scan signal supplied to the scan electrode of the corresponding line, and has the same width as that of the reset signal. The method of claim 1, And the erase signal is supplied in a form shifted from the lower to the higher luminance level. The method of claim 4, wherein And erasing signals corresponding to the luminance level are supplied such that a start edge portion has a predetermined time difference. In the data driving apparatus of the plasma display panel using a high frequency discharge, Sampling means for sampling an input analog video signal, Storage means for temporarily storing the sampled video signal in units of scan lines; Control means for reading out the stored sampling video signal and rearranging the stored sampling video signal with a luminance level and having a time difference according to the luminance level; And a data driving means for supplying a reset signal for starting the high frequency discharge every horizontal period and an erase signal according to the driving signal to the data electrode lines of the panel. . The method of claim 6, And said control means supplies said drive signal in a form shifted from the lower to the higher luminance level. The method of claim 6, And the erase signals according to the luminance level are supplied such that a start edge portion has a predetermined time difference. The method of claim 6, The reset signal is supplied in synchronization with a scan signal supplied to the scan lines of the panel, and the scan signal has the same width as the reset signal.