KR100431671B1 - Method for scanning double line on PDP television - Google Patents

Abstract

The present invention relates to a double-line scan method of a PDP television. In the conventional PDP driving, a constant scan time was required because all 480 lines of the vertical section had to be scanned. However, in order to improve the contrast of the screen, it is necessary to increase the subfield or increase the sustain discharge time, which causes a problem of relatively reducing the scan time.

In order to solve such a problem, in the PDP television gradation processing method in which the frame is divided into odd and even fields and scanned for one screen display, the same data is written in two lines when creating frames in the odd and even fields. Therefore, when scanning lines in odd and even fields, a predetermined number of scan electrode lines are bundled and scanned by two lines to overcome the time constraints of improving the contrast by reducing the line scan time in half.

Description

Method for scanning double line on PDP television

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-line scan method of a PDP television. In particular, when a PDP television is driven to perform a line scan, two lines are bundled and a double line scan is performed to reduce the line scan time in half to increase a subfield or to maintain a discharge. The present invention relates to a double-line scan method of a PDP television that can overcome the time constraints of increasing the contrast to improve the contrast.

In the image display method of a television, a CRT, which is a general television system, adopts a sequential scanning method in which an electron gun sequentially scans pixel by pixel, and the gray scale is made up of a simple driving circuit driven by an analog system. It is very fast as tens of nanoseconds (ns), but when the number of pixels is increased to millions such as HDTV, it is very difficult to implement the driving of millions of pixels by one pixel.

However, the PDP, which is a flat panel display, uses a matrix drive method using a strong nonlinearity characteristic of gas discharge, rather than scanning pixel by pixel. Nonlinearity is a characteristic of gas discharge. Since the gas discharge phenomenon is caused by ionization through the ionization process of the gas, the discharge occurs only when a voltage higher than the discharge voltage at which the ionization reaction can occur sufficiently is applied. Is a characteristic of gas discharge in which no discharge occurs.

On the other hand, the PDP is generally driven by a continuous pulse having a constant voltage, gray scale display is implemented by a digital method, not an analog method.

In the driving method for grayscale processing of the PDP, it is common to read even line data repeatedly after reading one line of odd line data for one field of image data stored in a memory. In this case, one field is divided into several subfields, and image data corresponding to each subfield is sequentially read and provided to the data interface unit.

The stimulus for the luminance felt by the visual system is proportional to the intensity of the light source, but also to the time of successive stimuli over time. Therefore, the PDP gray scale display system adopts a kind of time width modulation method of adjusting the ON time of inversion. For example, 256 gray scale display in this method is desired by dividing 255 pulses corresponding to 256 into 8 subfields (each subfield corresponding to 1,2,4,8, 16, 32,64, 128). The gray level is achieved by turning on each subfield corresponding to the gray level. Each subfield includes a full screen writing and erasing section, a scan section, and a sustain section.

As described above, the driving method of one subfield including the erasing section, the scanning section and the sustain section is performed in the following driving order.

First, the erasing section is an operation mode for discharging the discharge. In the case of AC PDP, in the period of neutralizing the wall charge, the discharge is formed at a low voltage so that the wall charge is not sufficiently formed, or an erase pulse having a short pulse width is applied to the wall. Eliminate wall charges by preventing charges from reaching steady state.

That is, in order to erase the wall charge remaining in the selected (discharged) pixel after the discharge sustain of the previous subfield, the wall charge is written to all the pixels for a short time which is not visible, and then all the pixels. Erasing all remaining wall charges to initialize the PDP, thereby erasing all of the remaining wall charges. The scan section 12 shifts the scan pulses to the line scan electrode in sequence, and then transfers the corresponding data through the data write electrode. To form a wall charge selectively on the pixel to be discharged by writing line by line, and the sustain section 14 has a data writing and scanning mode and a gas discharge storage function necessary for initial discharge formation. By using the characteristic, discharge sustain operation is performed in which the discharge is maintained by the sustain pulse having a voltage lower than that of the selected pulse. Further, in the driving method of one subfield as described above, the signal processing states of the full screen source section and the data writing and scanning section are fixed unchanged for each subfield. However, since the discharge sustaining section corresponds to the image display section, it functions differently for each subfield according to the length of the input data. That is, the discharge maintenance section is a variable section that gives a repetitive waveform by varying the discharge maintenance section by the weight of each digital data for gradation processing.

Fig. 1 shows a waveform diagram for the gradation processing of a conventional subfield, which is a waveform diagram of a write discharge section 10, a scan section 12, and a sustain discharge section 14. As shown in Figs.

In other words, immediately after the end of the write discharge, data writing and erasing are started with the first scan pulse 12a, and the sustain discharge starts without time after the last scan pulse 12b ends.

FIG. 2 shows a pulse waveform diagram of writing data into a conventional PDP panel. As shown in FIG. 2, conventionally, data is written sequentially over all lines, and one frame for a time corresponding to one field of a television signal. In order to obtain the data of the line which is not turned on by implementing the image, the data is recombined frame by frame using a memory. In the conventional data writing method, the same frame is sustained twice, and 30 different screens are turned on in one second, but 60 complete images are displayed.

In the conventional PDP drive, since all 480 lines of the vertical section are scanned, the required scan time is about 480 × 8 (subfield) × 3 μsec = 11.52 msec.

In addition, in order to make the screen brighter, it is necessary to increase the subfield or to increase the discharge time, which causes a problem in that the scan time is relatively shortened.

For this reason, the conventional line scan method has a time limit to increase the subfield or increase the discharge time to brighten the screen.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and when the PDP television is driven to perform a line scan, two lines are bundled to perform a double line scan to reduce the line scan time in half to increase the subfield or to maintain the discharge time. It is an object of the present invention to provide a double-line scan method of a PDP television that can overcome the time constraints of increasing contrast to improve contrast.

As a technical idea for achieving the object of the present invention, the frame is composed of odd and even subfields for one screen display, wherein the subfield is a full screen erasing section, a data writing and scanning section, and a discharge holding section. A gradation processing method of a PDP television having a digital display, comprising the steps of: sequencing a predetermined number of Y-axis scanning electrode lines by two lines during the data writing and scanning periods to sequentially write the same data every two lines; This is presented.

1 is a waveform diagram of a gradation process by a conventional subfield method;

2 is a pulse waveform diagram showing a scanning method of a conventional PDP;

3 is an overall block diagram of a PDP television system;

4 is a reference diagram illustrating a scanning method of a PDP according to the present invention.

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

1: AV unit 2: ADC unit

3: memory section 4: data interface section

5: timing controller 6: address driver IC

7: holding / scanning driving IC 8: high voltage driving circuit

9: AD / DC converter 80: composite video signal processor

90: digital data processing unit 100: PDP drive unit

Hereinafter, with reference to the accompanying drawings with respect to the configuration and operation of the embodiment of the present invention will be described.

As shown in FIG. 3, a PDP-TV generally includes a composite video signal processing unit 80 including an AV unit 1 which analog-processes a composite video signal received through an antenna and provides it to an ADC unit. ADC unit 2 for sampling and processing analog composite video signals into digital data, memory unit 3 for rearranging digital image data input from the composite video signal processing unit 80, and rearranged digital image data A data interface unit 4 for inputting a data stream into a data stream suitable for the PDP gradation process, a memory controller 3, and a timing controller unit 5 for generating and supplying a main clock to control the entire system. The digital data processor 90 receives the data stream from the data interface 4 and supplies data to the plasma panel for grayscale processing. It consists of a dress to the drive IC (6) and hold / drive scan IC (7) PDP driving unit 100. The

The AV unit 1 receives the NTSC composite signal, separates the analog R, G, and B signals from the horizontal and vertical synchronization signals, obtains an APL (Average Picture Level) corresponding to the average value of the luminance signal, and provides the ADC unit 2 with the signal. Supply. This APL is used to improve the brightness of PDP television systems. The NTSC composite video signal has an interlaced scanning method, in which one frame is composed of two fields of odd / even, the horizontal synchronous signal has a frequency of about 15.73 KHz, and the vertical synchronous signal has a frequency of about 60 Hz. The audio signal separated from the composite video signal is output through the audio amplifier directly to the speaker. The ADC unit 2 receives analog R, G, and B signals as inputs, converts them into digital data, and outputs the digital data to the memory unit 3. In this case, the digital data is converted into image data in order to improve the brightness of the PDP television. to be.

The ADC 2 is divided into an amplifier, a clock generator, a sampling area setting unit, and a data mapping unit. The amplifying section in the ADC section 2 amplifies the analog R, G, B and APL signals to a signal level suitable for quantization, and converts the horizontal and vertical synchronization signals into a constant phase and outputs them. The sampling clock of the clock generator must use a clock synchronized with the input synchronous signal. For this purpose, a clock is generated using a PLL. The PLL is oscillated by the LF (L00p Filter) which outputs the control voltage of PD (Phase Detector), VCXO (Voltage Controlled Crystal Oscillator), which compares the phase of the input synchronous signal and the phase of the variable pulse output from the loop. A VCXO and a PC (Programmable Counter) for dividing the output of the VCXO and outputting a phase comparison pulse to output a clock synchronized with the input synchronous signal.

If the clock synchronized to the input synchronization signal is not used, the vertical linearity of the displayed image is not guaranteed.

In addition, the sampling area is set to a vertical position and a horizontal position. The vertical position section is a pulse for setting only the line with the image information among the input signals, and the horizontal position section is a pulse for setting only the time with the image information among the lines set as the vertical position. The vertical position section and the horizontal position section are the standards for sampling. At this time, 240 lines of Odd / Even fields are selected and a total of 480 lines are selected. The horizontal position section should be such that there can be at least 853 sampling clocks per selected line. The data mapping unit of the ADC unit 2 performs 1: 1 mapping of the R, G, and B data output from the A / D converter, and provides the improved R, G, and B data to the memory unit 3 in the form of improved R, G, and B data.

For PDP gradation processing, it is necessary to reconstruct video data of one field into a plurality of subfields and then rearrange them from the most significant bit (MSB) to the least significant bit (LSB).

In addition, since the image data inputted by the interlaced scanning method is converted into the sequential scanning method and displayed, an area for storing one frame of image data is required.

That is, by providing two frame memories that can store one piece of image data (853 × 3 (RGB) × 480 × 8Bit ≒ 10Mbit), they alternately perform write and read operations in units of frames. Allows you to store and display video data continuously. Further, in the PDP gradation process, one field is divided into several subfields, and image data corresponding to each subfield is read in order and provided to the data interface unit 4.

The data interface unit 4 temporarily stores R, G and B data from the memory unit 3 and provides the data in the form of data required by the address driver IC 6. It is arranged in accordance with the R, G, and B pixel arrangements output from the memory unit 3, and must be driven by the address driving IC 6, which is why the data interface unit 4 is required.

Referring to the case where the display size is 853 x 3 (R, G, B) x 480 mode in the above PDP television system, the data interface unit 4 stores one line of data (853 x 3 = 2559 bits). Temporary storage is required, and since data continuity must be guaranteed (input and output are performed simultaneously), 2 lines of temporary storage (2559 × 2 = 5118 bits) are required.

That is, a total of 24 bits of data of 8 bits each of R, G, and B from the memory unit 3 are sequentially inputted (107 times) into the first temporary storage area (24 bits × 107 = 259 bits), and the same time interval As a result, the previous one-line amount of data of the second temporary storage area is output in the form of a data stream required by the address driver IC 6.

Such input / output operations alternately occur in the first and second temporary storage areas. That is, after the first temporary storage area operates in the input mode and the second temporary storage area operates in the output mode, the operation is then reversed. When outputting the temporarily stored image data to the address driver IC 6, the data interface unit 4 provides one bit of data and a total of 48 bits of image data to each driver IC in the form of a stream.

In this way, when data is input to the driver IC in turn (75 times) and shifted in parallel, one line (48 bits x 75 = 3600 bits) of image data is all loaded into the address driver IC 6. Since this process should be the same as the input mode operation time of other temporary storage areas, the input mode should be operated at twice the frequency of the output mode.

The high voltage drive circuit 8 is required by the address, scan and sustain driver IC by combining the DC high voltage supplied from the AC / DC converter 9 according to the control pulses of various logic levels output from the timing controller 5. Generate a control pulse to drive the PDP.

In addition, the data stream provided from the data interface unit 4 to the address driver IC 6 is also raised to an appropriate voltage level to enable selective writing on the panel. As described above, the driving method for the PDP gradation process first divides one field (60 Hz) into several subfields (64 gradations: 6 subfields, 256 gradations: 8 subfields), and then divides the image data corresponding to each subfield. The address is written to the panel line by line via the address driver IC 6.

It is common to reduce the number of inversion sustain pulses in the order of LSB subfields in the subfield to which MSB data is written, and to perform gradation processing for these combinations at different total discharge sustaining periods. In addition, the driving sequence of all subfields repeats operations of full screen writing and erasing, data writing, and discharge holding (screen display). The process is outlined as follows.

First, in the case of AC PDP, in the case of AC PDP, an inverted voltage is formed at a low voltage in the period of neutralizing the wall charge so that the wall charge is not sufficiently formed or an erase pulse having a short pulse width is applied so that the wall charge is in a steady state. The wall charges are written to all pixels in a short time which is not visible to remove the wall charges so as not to reach, i.e., to erase the wall charges remaining in the selected (discharged) pixels after sustaining the discharge of the previous subfield. Next, all screens are erased by erasing all remaining wall charges by erasing all pixels.

Next, in the case of the He + Xe and Ne + Xe penning mixtures generally used in the PDP, a potential of 240 V to 280 V is applied. In the case of AC, the third electrode is introduced to reduce the high current caused by the sustain electrode in the surface discharge form and the parasitic capacitor caused by the dielectric, and adopts a driving method that separates the selection operation from the sustain operation.

According to the present invention, as shown in FIG. 4, the two lines of the Y-axis scan electrode are sequentially scanned (1 to 240) at a time, and the pixels are selectively written and discharged by writing the data in line units through the data writing electrode. A data writing and scanning process, which is a driving operation necessary for initial discharge formation, is performed to form wall charges.

Next, in the case of AC PDP, in practice, sustain pulses are alternately applied between the discharge sustain driver electrode and the line scan electrode to start and sustain the discharge of the pixel on which the wall charges are formed. At this time, since the pixel which is not written is influenced by the written peripheral pixel, and there is a possibility of causing an error discharge, a discharge sustaining process is performed so that a small amount of erase is performed every time the sustain pulse is applied to make an accurate discharge.

The AC / DC converter 9 generates and supplies the high voltage required to combine the electrode driving pulses with the AC power as an input, and the DC voltage required by each part constituting the other PDP television system.

The present invention relates to a method of scanning in the plasma panel of the PDP system as described above, Figure 4 shows a scan line of the even field and the odd field by the double line scan method.

That is, the scan line is 480 lines in the scanning electrode on the Y axis is bundled by two lines, one end is short. The X axis is a common electrode.

Therefore, as the holding and scanning driving IC 7 is driven, first, the scan lines of the odd field are sequentially scanned. This process is as follows.

That is, Y1 is scanned by tying the first line Y1-1 and the second line Y1-2, and then Y2 is connected by tying the third line Y2-1 and the fourth line Y2-2. As described above, Y3, Y4, Y5, Y6, ..... Y239, which are bundled in two lines, are scanned and a total of 240 scannings are performed to create one subfield.

As described above, when the scan of the odd field is completed, the scan of the even field is started. In this case, like the scanning method of the odd field, 240 scans are performed by scanning two lines of 480 scan lines. This creates another subfield.

Therefore, the line scan time in the vertical section is reduced by half compared to the past.

As can be seen from the above description, in the gradation processing method of a PDP television in which the frame is divided and scanned into odd and even fields for one screen display, two lines are used when making frames in odd and even fields. By scanning the same data every two lines and scanning the lines in odd and even fields, a certain number of scanning electrode lines can be bundled and scanned in two lines to reduce the line scan time by half, increasing the subfield or increasing the discharge time. There is an effect that can overcome the time constraints of improving the contrast (contrast).

In addition, if the number of times of scanning is actually reduced by half, the number of scan driving ICs is also reduced by half, thereby reducing the manufacturing cost.

Claims (1)

In a gradation processing method of a PDP television in which a frame is composed of odd and even subfields for one screen display, and the subfields have an entire screen erasing section, a data writing and scanning section, and a discharge holding section. And scanning a plurality of Y-axis scanning electrode lines by two lines during the data writing and scanning period, and sequentially scanning the same data for two lines.