KR100280887B1 - Driving device of plasma display panel - Google Patents

Abstract

The present invention relates to a driving device of a plasma display panel.

A driving apparatus for a plasma display panel according to the present invention includes a display panel for displaying image data continuously input, image detection means for detecting a change in a continuous image displayed on the display panel, and a plasma corresponding to the amount of change in the image. A driving control unit is configured to control driving of the display panel.

Accordingly, the driving apparatus of the plasma display panel according to the present invention reduces power consumption of the plasma display panel and improves contrast of the screen.

Description

Apparatus of Driving for Plasma Display Panel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display, and more particularly, to a driving device of a plasma display panel which can reduce power consumption and improve contrast.

Recently, Liquid Crystal Display (hereinafter referred to as "LCD"), Field Emission Display (hereinafter referred to as "FED") and Plasma Display Panel (hereinafter referred to as "PDP") Flat display devices such as PDP have been actively developed. Among them, PDP is easy to manufacture due to its simple structure, high brightness and high luminous efficiency, memory function, and has a wide viewing angle of 160 ° or more, and realizes a large screen of 40 inches or more. It has the advantage of being able to. The PDP obtains a discharge through voltage control applied between vertical and horizontal electrodes of a cell constituting a pixel, and the amount of light discharged is controlled by changing the length of the discharge time in the cell. That is, the PDP includes a write pulse for inputting a digital image signal to the vertical and horizontal electrodes of each cell, a scan pulse for scanning, a sustain pulse for maintaining a discharge, and a discharged cell. An erase pulse is applied to stop the discharging of the substrate, thereby driving the matrix. Here, the step brightness required for image display, that is, gray scale, is a time for discharging individual cells within a time when a screen of one frame is displayed (for example, 1/30 second for an NTSC TV signal). It is expressed by implementing different lengths of. Contrast, which represents the difference in contrast, is determined by the brightness and luminance of the background, such as lighting. In order to increase the contrast, not only the background needs to be darkened, but also the brightness needs to be increased. Such PDPs are generally classified into AC and DC types according to driving methods. Among the AC PDP driving methods, an ADS (Addressing Display Separated) driving method is a method of dividing and driving one frame into a plurality of subfields according to the gray scale to be implemented.

Referring to Figure 1, the configuration of one frame according to the conventional PDP driving method is shown. In general, one frame having a time of 16.67 ms is composed of eight subfields to implement a 256-gradation image. Each subfield consists of an address section and a sustain section. The address section of each subfield is a section for accumulating wall charges such that sustain discharge is possible for the pixels to be lit by the address discharge. To this end, in the address period of the first subfield SF1, a writing pulse is applied between the Y and Z sustain electrodes to form wall charges in the cell. Subsequently, the address discharge is caused by the image data pulses applied to the address electrodes and the scan pulses applied to the Y sustain electrodes so that wall charges are formed inside the cells to be lit. At this time, the address section is indicated by an oblique line in FIG. In the address period of the second subfield SF2, an erase pulse is applied between the Y and Z sustain electrodes to erase the wall charges formed by the sustain discharge in the sustain period of the first subfield SF1. The sustain section of each subfield is a section in which a sustain discharge is generated only for a cell in which an address discharge is generated by applying a sustain pulse to the wall charge. To this end, a sustain voltage (V _S ) pulse is applied between the Y and Z sustain electrodes to be added to the wall charges formed inside the lit cell in the address section to generate a sustain discharge, thereby determining the relative value of luminance. At this time, the sustain period is shown as a curve that increases and decreases exponentially in FIG.

As described above, in order to realize the gray level, there is an addressing section and a sustain discharge section in every subfield, so that the addressing section, which is a non-display period, is longer than the sustain discharge, which is a display section. In addition, even when only a minute portion of the screen or a still image in which the same data is continuously moved is repeatedly driven as described above every frame, unnecessary addressing is continuously repeated to increase unnecessary power consumption. Since the discharge of the plasma display panel uses a secondary discharge generated by the ultraviolet rays generated by the voltage excitation of the fluorescent layer, the luminous efficiency is not high. Therefore, a high voltage is required to compensate for this, so it is necessary to minimize the power consumption in the addressing section. . Another drawback is that a weak discharge that can occur in the addressing section lowers the black level at which light is displayed in the non-display section, thereby degrading the contrast of the panel.

Accordingly, an object of the present invention is to provide a driving apparatus of a plasma display panel which can reduce power consumption and improve contrast.

1 is a view showing the configuration of one frame to explain a method of driving a plasma display panel according to the prior art.

2 is a view showing a driving device of a plasma display panel according to a first embodiment of the present invention;

3 is a view showing a driving device of a plasma display panel according to a second embodiment of the present invention;

4 is a view showing a driving device of a plasma display panel according to a third embodiment of the present invention;

5 is a characteristic diagram showing a characteristic curve of luminance according to the present invention;

<Description of Symbols for Main Parts of Drawings>

2: Analog-to-digital converter 4: First memory

6: second memory 8: memory controller

10: counter 12: multiplexer

14 comparison unit 16 waveform generation unit

18: address electrode driver 20: sustain electrode driver

22: plasma display panel 24: output processing unit

In order to achieve the above object, a driving apparatus of a plasma display panel according to the present invention includes a display panel for displaying image data continuously input, image detection means for detecting a change in a continuous image displayed on the display panel, and an image. And a driving control unit for controlling the driving of the plasma display panel in response to the change amount of the.

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.

With reference to Figures 2 to 3 will be described a preferred embodiment of the present invention.

Referring to FIG. 2, a driving apparatus of a plasma display panel according to a first embodiment of the present invention includes an analog / digital converter (A / D converter) 2 or less that converts an input video signal into digital. And first and second memories 4 and 6 for temporarily storing digitally converted data, and a multiplexer 12 for selecting and outputting image data of one of the memories 4 and 6. And a comparator 14 for detecting movement by comparing the image data stored in the memories 4 and 6, a sustain electrode driver 20 for driving the panel by waveforms generated according to the comparison result, An address electrode driver 18 for driving the plasma display panel 22 according to the selected image data is provided. The operation of the driving circuit will be described in detail. First, an input video signal is separated into R, G, and B color signals, and converted to have a digital data value through an A / D converter 2. It is usually converted to 8-bit data suitable for 256 gradation expression. 8-bit data is temporarily stored in the memories 4 and 6 as much as one frame screen. The stored data is typically transmitted to the address electrode driver 18 to drive the plasma display panel 22. The comparison unit 14 adds a comparison unit 14 that detects the amount of change or movement of the screen in the continuous screen by comparing the previous frame and the subsequent frame which are continuously inputted with the data stored in the memories 4 and 6. As a result, a sustain waveform for the sustain electrode driver 20 is generated and address electrode driving for addressing the plasma display panel 22 is performed. That is, when the data currently displayed on the screen is compared with the data to be displayed next, and the result of the comparison determines that the same data is the same, the address electrode driver 18 and the holder are configured to enable only sustain discharge in the same addressing state without additional addressing. The electrode driver 20 is controlled. On the other hand, when the data of the current screen and the data of the subsequent screen do not match, the address electrode driver 18 and the sustain electrode driver 20 are controlled to perform all discharges such as preliminary discharge, address discharge, and sustain discharge. For example, in the case of a still picture without motion of the image, or in the case where only some pixel data of the screen such as a mouse position change or a word process is changed in the entire screen, the display undergoes this comparison step and there is no motion change. Since the drive is controlled to generate only sustain pulses, power consumption is reduced. The multiplexer 12 serves to select one of the first memory 4 and the second memory 6 and to export it as display data. That is, image data of one frame that is continuously input is temporarily stored and displayed in the first memory 4, and this image data is not overwritten by the next data as in the prior art so as to be compared with the image data of the next frame. The frame data is further maintained for one frame and the next frame data is instead stored in the second memory 6 and compared with the data of the first memory 4 which is the data of the currently displayed screen. Therefore, in the next frame, the multiplexer 12 must send the data of the second memory 6 to the address electrode driver 18 of the panel and repeat this process.

The present invention will be described with reference to the following detailed drawings.

Referring to FIG. 3, a driving apparatus of a plasma display panel according to a second embodiment of the present invention includes an A / D converter 2 connected to an input line and an output terminal of the A / D converter 2. A multiplexer 12 connected to the first and second memories 4 and 6, an output terminal of the first and second memories 4 and 6, a counter 10 connected to a data clock line, and a counter ( To the memory control section 8 connected to the output terminal of 10, the comparator 14 connected to the counter 10 and the output terminals of the first and second memories 4 and 6, and to the output terminal of the comparator 14. The connected waveform generator 16, the address electrode driver 18 connected to the output of the waveform generator 16 and the multiplexer 12, and the sustain electrode driver connected to the output of the waveform generator 16; 20 and a plasma display panel 22 connected to an output terminal of the address electrode driver 18 and the sustain electrode driver 20. The A / D converter 2 converts analog image information transmitted from an input line into 8-bit pixel data. The first and second memories 4 and 6 temporarily store pixel data. That is, the memory 4, 6 stores pixel data by frame, subfield and color by the control of the memory controller 8, and compares the pixel data stored by the control of the memory controller 8. 14) or outputted to the multiplexer 12. At this time, the first memory 4 stores the pixel data displayed on the current screen, and the second memory 6 stores the pixel data displayed next on the screen. On the other hand, the counter 10 counts the position of the pixel data output from the A / D converter in synchronization with the reference clock pulse. The memory controller 8 outputs the pixel data stored in the first and second memories 4 and 6 to the comparator 14 with reference to the counting signal output from the counter 10. In addition, the memory controller 8 selectively outputs pixel data stored in the first and second memories 4 and 6 to the multiplexer 12 with reference to the comparison signal output from the comparator 14. The comparator 14 compares whether the pixel data transmitted from the first and second memories 4 and 6 are the same by referring to the counting signal output from the counter 10. That is, when the pixel data currently displayed on the screen and the pixel data to be displayed next on the screen are determined to be the same data, the waveform generator 16 is controlled to perform only sustain discharge. On the other hand, when the data displayed on the screen and the data displayed on the next screen do not match, the waveform generator 16 is controlled to perform preliminary discharge, address discharge, and sustain discharge. For example, when the position of the mouse is changed on the screen or when a word process or the like is in operation, only a part of pixel data of one screen is changed and the remaining screens are the same. The comparator 14 controls the waveform generator 16 to generate only a sustain pulse in the same part of the pixel data applied from the first and second memories 4 and 6, while the first and second memories ( The waveform generation unit 16 is controlled to generate write pulses, erase pulses for pre-discharge, address pulses for address discharge, and sustain pulses for sustain discharge in areas where the pixel data applied in 2 and 4 do not match. Done. As a result, only the sustain discharge is performed when the pixel data to be displayed on the screen is not changed, and all the discharges are not performed in the case of full black. In addition, when only a specific line is black, discharge is not performed in the corresponding line. The waveform generator 16 generates each pulse in response to the comparison signal output from the comparator 14. That is, in response to the comparison signal, a write pulse, an erase pulse, an address pulse for address discharge, a sustain pulse for sustain discharge, and the like are generated. The multiplexer 12 sequentially converts the pixel data transmitted from the first and second memories 4 and 6 to each pixel data from the most significant row bit to the least significant bit by the comparison signal of the comparator 14. Output to the drive part 18. FIG. The address electrode driver 18 applies the pixel data transmitted from the multiplexer 12 and the sustain pulse output from the waveform generator 16 to drive the address electrodes. The sustain electrode driver 20 applies the pulse generated by the waveform generator 16 to drive the sustain electrodes. As described above, the plasma display driving apparatus according to the second embodiment of the present invention compares the pixel data stored in the first and second memories to perform only sustain discharge when they are the same, and only the specific line when the specific line is black. Does not allow discharge to be performed. In addition, in the case of full black, the electric power consumption of the plasma display panel is reduced by not discharging all the discharges, and in the same screen, preliminary discharges and address discharges are not performed, thereby improving the contrast of the screens. Let's go.

Referring to FIG. 4, a driving apparatus of a plasma display panel according to a third exemplary embodiment of the present invention includes an A / D converter 2 for converting an input image signal into digital and a temporarily storing data converted into digital. The first and second memories 4 and 6, the multiplexer 12 which selects and outputs one of the image data among the memories 4 and 6, and the image data stored in the memories 4 and 6 are compared. And a comparator 14 for detecting movement, a sustain electrode driver 20 for driving the panel by the waveform generated according to the comparison result, and a plasma display panel 22 by the image data selected according to the comparison result. An address electrode driver 18 for driving the &quot;, &quot; and an output processor 24 for correcting the value of the image data to be output according to the comparison result. In the first and second embodiments, the comparison unit compares pixel data of two frames 1: 1 and compares them in block units of n * n pixels, so that they are regarded as the same screen even if they are not completely identical or almost similar. It is also possible to display only by sustain discharge without performing separate addressing. Alternatively, it is possible to compare the entire frame at once. In this case, it is also possible to correct the image data to make the black portion more black and the white portion brighter to compensate for the contrast of the entire screen. To this end, an additional output processing unit 24 may be added, and an apparatus for correcting the image data value to be output according to the comparison result of the comparison unit 14 may be added. That is, the output processing unit 24 is controlled to perform output processing for compensating for luminance of the screen when the compared data match, and to output the original input data as it is. At this time, the luminance has a characteristic curve as shown in FIG. 5, and the contrast is improved.

As described above, the plasma display driving apparatus according to the third embodiment of the present invention compares the pixel data stored in the unit of block in the memory and performs the sustain discharge only, and adjusts the luminance level so that the black on the screen becomes more black. The white light level is corrected to correct the luminance level, thereby driving the plasma display panel. As a result, when only a specific line is black, discharge is not performed on the line. In addition, in the case of full black, the electric power consumption of the plasma display panel is reduced by not performing all the discharges, and the contrast of the screen is improved.

As described above, the plasma display panel according to the present invention has the advantage of reducing the power consumption of the plasma display panel and improving the contrast of the screen.

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 (6)

A display panel which displays a video signal which is continuously input; An address electrode driver for selecting a cell to be displayed in the display panel and simultaneously applying the input image signal to a data electrode; A sustain electrode driver for applying a voltage to a pair of sustain electrodes to maintain the discharge of the selected cell to display the image signal; Comparison detecting means for comparing the continuously input video signal with a previous image signal and detecting a change thereof; A drive control unit controlling to selectively drive the sustain electrode driving unit and the address electrode driving unit according to the detection result of the comparison detecting unit; And an output processor configured to be connected between the display panel and the comparison detecting means to adjust the luminance values of the image signals when it is determined that the previous image signal and the next image signal are the same as the comparison result of the comparison detecting means. Driving device of plasma display panel. The method of claim 1, A first memory in which the comparison detecting means temporarily stores data corresponding to the previous video signal; A second memory for temporarily storing data corresponding to the next video signal; And a comparison means for comparing the image data stored in the first memory and the second memory to detect whether the image signals are the same. The method of claim 1, The driving control unit controls to perform only sustain discharge without performing address discharge of the plasma display panel when it is determined that the comparison result of the comparison detecting means is the same or similar within a predetermined range. Driving device of plasma display panel. The method of claim 1, And the driving control unit controls not to perform all discharges when it is determined that there is no input signal as a result of the comparison of the detection means. The method of claim 6, And the output processor increases the luminance value of the image signal having a high luminance value and decreases the luminance value of the image signal having a low luminance value. The method of claim 1, And the comparison of the input data in the comparison detecting means is performed on a line basis, a block basis, or the entire panel.