KR100292535B1 - Driving method and apparatus of plasma display device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for driving a plasma display device in which contrast and brightness can be adjusted without deterioration of image quality.

The present invention adjusts the contrast and brightness with respect to the input video signal by adding or subtracting the number of sustain pulses.

According to the present invention, since contrast and luminance can be adjusted without degrading the gray scale, natural colors can be expressed.

Description

Methods of Driving Plasma Display and Apparatus Thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display for displaying a digital video signal. More particularly, the present invention relates to a method and an apparatus for driving a plasma display device to adjust contrast and brightness without deterioration of image quality.

The display device must make the contrast and luminance available to the user. In general, a cathode ray tube (CRT) monitor or a TV that displays a video signal in an analog manner is controlled by adjusting a bias voltage applied to a grid of an electron gun in a final output circuit as shown in FIG. 1A. Then, the contrast is adjusted by adjusting the gain of the input signal as shown in FIG. In this analog system, infinite color display is possible, and so far, cathode ray tubes are widely used than other display devices. However, in flat panel displays such as liquid crystal displays and plasma displays that display video signals digitally, the video signals are digitized and displayed, and due to the limitations of digital methods, infinite color display is impossible, so users cannot recognize them until now. The color is indicated by.

2 is a block diagram showing a driving apparatus of a conventional plasma display device.

Referring to FIG. 2, a driving apparatus of a conventional plasma display apparatus includes an analog / digital converter connected in series with a contrast / luminance adjusting unit 2 into which a video signal and a user control signal are input, and a contrast / luminance adjusting unit 2 (hereinafter An `` A / D converter '' 4, an inverse gamma correction unit 6 connected in series with the A / D converter 4, and a multiplexer connected in series with the inverse gamma correction unit 6; 8, a memory 10 serially connected to the multiplexer 8, a demultiplexer 8 serially connected to the memory 10, and a column driver 18 serially connected to the demultiplexer 8; A controller 12 commonly connected to the memory 10 and the demultiplexer 14, a column driver 18 and a row driver 20 commonly connected to the controller 12, a column driver 18, and a row. A plasma display panel (hereinafter referred to as "PDP") 21 connected to the driver 18 is provided. As can be seen in FIG. 3, the PDP 21 has m × n pixel cells arranged in a matrix. The pixel cells are provided with n data electrodes (hereinafter referred to as ″ X electrodes ″) 1 to which digital video data of red and green (RGB) are supplied, and m scan / maintenance electrodes arranged side by side crossing the X electrodes 1. (Hereinafter referred to as "Y electrode") 3 and a common sustain electrode (hereinafter referred to as "Z electrode") 5 are formed. The driving of the PDP 21 is synchronized with the scanning pulse in the address period including the reset period in the subfield method, and the digital video data is supplied to the X electrode 1 and the Y electrode 3 and the Z electrode 5 by the sustain pulse. Video data is displayed by performing surface discharge in between. The contrast / luminance adjuster 2 separates the input video signal into a luminance signal and a red-green-blue (RGB) color signal, adjusts the contrast by adjusting the gain of the luminance signal, and adjusts the luminance by adjusting the bias of the luminance signal. . The A / D conversion section 4 serves to digitize the signal from the contrast / luminance adjustment section 2. The inverse gamma correction unit 6 inversely gamma corrects the gamma corrected signal to the PDP 21. The output signal of the inverse gamma correction unit 6 is rearranged in time in the multiplexer 8, the memory 10, and the demultiplexer 14 by the control of the controller 14 and spatially suitable for driving the matrix of the PDP 10. To be relocated. The controller 12 controls the memory 10 and the demultiplexer 14, and supplies timing signals necessary for the column driver 18 and the row driver 20. The column driver 18 supplies one line of video digital data to the X electrodes 1 in synchronization with the scan pulse to drive the X electrode 1. The row driver 20 supplies a sustain pulse to the Y electrode 3 and the Z electrode 5 so as to display video data, thereby causing surface discharge between the Y electrode 3 and the Z electrode 5.

As can be seen from FIG. 2, in a plasma display device that digitally represents the gray level of an image, margin for adjusting contrast and luminance and margin for inverse gamma correction should be given. The margin for contrast and luminance adjustment and the margin for inverse gamma correction become obstacles to natural image display in inverse proportion to the gray scale (for example, 256 gray scales) as shown in FIG. 4. Moreover, as the PDP characteristic is not constant, the margin increases, so that the gray level is lowered. Another cause of lowering the gray level is that the red phosphor emits different light emission characteristics, so that the red phosphor is 97% when the green phosphor is 100% to achieve the white balance. However, the blue (B) phosphor needs to have an additional adjustment margin because the applied voltage should be about 89%. In order to solve this problem, the A / D converter 4 needs to increase the number of bits and increase the number of subfields when converting an analog signal into a digital signal. This method requires additional manufacturing cost, lowers luminance, increases address speed, and increases the number of subfields, which causes many problems in high resolution display.

Accordingly, it is an object of the present invention to provide a method and apparatus for driving a plasma display device in which contrast and brightness are adjusted without degrading gray scale.

Another object of the present invention is to provide a method and apparatus for driving a plasma display device capable of displaying an image in full gray scale without increasing the number of bits in analog / digital conversion.

It is still another object of the present invention to provide a method and apparatus for driving a plasma display device capable of displaying an image in full gray scale without increasing the subfield.

It is still another object of the present invention to provide a method and apparatus for driving a plasma display device suitable for high resolution display.

1A is a characteristic diagram showing a conventional brightness adjusting method.

1B is a characteristic diagram showing a conventional contrast adjustment method.

2 is a block diagram showing a driving apparatus of a conventional plasma display device.

3 is a view illustrating in detail the plasma display panel shown in FIG.

4 is a characteristic diagram showing a relationship between a contrast / luminance adjustment margin and a gray scale in the related art.

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

6 is a block diagram illustrating a driving device of a plasma display device according to another exemplary embodiment of the present invention.

Fig. 7 is a view showing a contrast / luminance adjustment area in the driving apparatus of the plasma display device of the present invention.

<Description of the code | symbol about the principal part of drawing>

1: X electrode 2,22: Contrast / luminance adjustment unit

3: Y electrode 4, 24: A / D conversion part

5: Z electrode 6: reverse gamma correction unit

8: multiplexer 10: memory

12,32 controller 14 demultiplexer

18: column driver 20: row driver

21: PDP

In order to achieve the above object, the driving method of the plasma display device according to the present invention includes adjusting the contrast with respect to the input video signal by subtracting the number of sustain pulses.

A method of driving a plasma display device according to the present invention includes adjusting brightness of an input video signal by adding or subtracting a number of sustain pulses.

The driving apparatus of the plasma display device according to the present invention includes a display panel in which pixel cells are arranged in a matrix, contrast adjustment means for converting a contrast adjustment value into digital information according to a user control signal by receiving a user control signal, and contrast adjustment. And control means for controlling the number of sustain pulses according to the value, and drive means for generating the sustain pulses under the control of the control means to drive the display panel.

The driving apparatus of the plasma display device according to the present invention includes a display panel in which pixel cells are arranged in a matrix, contrast adjustment means for converting a contrast adjustment value into digital information according to a user control signal by receiving a user control signal, and contrast adjustment. Comparison discrimination means for adjusting a white balance for each color signal by comparing a value with an input video signal, control means for controlling the number of sustain pulses by using an output signal of the comparison discrimination means, and sustain pulses under control of the control means. And driving means for driving the display panel.

According to an exemplary embodiment of the present invention, a driving apparatus of a plasma display device includes a display panel in which pixel cells are arranged in a matrix, luminance adjusting means for converting luminance adjustment values into digital information according to a user control signal by receiving a user control signal, and luminance adjustment. And control means for controlling the number of sustain pulses according to the value, and drive means for generating the sustain pulses under the control of the control means to drive the display panel.

According to an exemplary embodiment of the present invention, a driving apparatus of a plasma display device includes a display panel in which pixel cells are arranged in a matrix, luminance adjusting means for converting luminance adjustment values into digital information according to a user control signal by receiving a user control signal, and luminance adjustment. Comparison discrimination means for adjusting a white balance for each color signal by comparing a value with an input video signal, control means for controlling the number of sustain pulses by using an output signal of the comparison discrimination means, and sustain pulses under control of the control means. And driving means for driving the display panel.

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

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 5 to 7.

5 is a block diagram illustrating a driving apparatus of a plasma display device according to an exemplary embodiment of the present invention.

In the configuration of FIG. 5, the driving apparatus of the plasma display device according to the present invention includes a contrast / luminance adjusting unit 22 for converting a change amount of contrast and luminance into digital information according to a user control signal for contrast and luminance adjustment, and an analog device. An A / D converter 24 for digitizing the video signal of the type, an inverse gamma correction unit 6 for inverse gamma correction of the gamma corrected signal to the PDP 21, and an inverse gamma corrected video data For supplying digital video data to the X electrode 1 of the PDP 21, and the multiplexer 8, the memory 10, and the demultiplexer 14 for rearranging the PDP 21 in a time and space suitable for the PDP 21. The driver 18 and the row driver 20 for driving the Y electrode 3 and the Z electrode 5 of the PDP 21 are provided. The PDP 21 is substantially the same as that shown in FIG. 3, and thus a detailed description thereof will be omitted. The A / D converter 24 digitizes the analog input video signal. The inverse gamma correction unit 6 inversely gamma corrects the signal from the A / D conversion unit 24 gamma corrected by the NTSC TV system to the PDP 21 and supplies it to the multiplexer 8. The multiplexer 8 supplies the image signal input in real time from the inverse gamma correction unit 6 to the memory 10 so as to correspond to the pixel cells to be displayed on the PDP 21. The memory 10 rearranges and stores video data input from the multiplexer 8 frame by frame and bit by bit under the control of the controller 32. The demultiplexer 14 rearranges the video data input from the memory 10 by the control of the controller 32 and supplies it to the column driver 18. The column driver 18 supplies one line of digital video data to the X electrodes 1 in synchronization with the scan pulse supplied from the controller 32. The contrast / luminance adjuster 22 is commonly connected to the controller 32 and the row driver 20. When the user adjusts the contrast or the luminance, the contrast / luminance adjuster 22 converts the amount of change into digital information to convert the controller 32 and the row driver 20. ) To serve. The control unit 32 controls the number of sustain pulses in each subfield by adjusting the number of sustain pulses necessary for the adjustment in accordance with the contrast / luminance conversion information supplied from the contrast / luminance adjustment unit 22. The row driver 20 adjusts the sustain pulse adjusted by the contrast / luminance change adjusted by the control of the controller 32 and supplies it to the Y electrode 3 and the Z electrode 5 to supply the Y electrode 3 and the Z electrode. A sustain discharge is caused between the electrodes 5.

The contrast / luminance adjustment method will be described below in contrast to the conventional contrast / luminance adjustment method. Conventionally, when the integer value of the input video signal is 63, if the brightness of the input video signal is adjusted, the bias adjustment value N for brightness adjustment is added to the value to be 63 + N. When the video signal is displayed on the PDP 21 with the adjusted luminance, the number of sustaining pulses of each subfield is always constant (for example, if 256 gray levels are expressed, the ratio of luminance of each of the eight subfields is 1: 2). : 4: 8: 16: 32: 64: 128), and if this change value is 63 + N and N = 2, the 0th and 6th subfields are turned on to display the video data with the changed luminance, but it is gray. There is a problem that the scale is lowered. In contrast, in the present invention, the number of sustain pulses corresponding to the change N according to the contrast / luminance conversion information supplied from the contrast / luminance adjustment unit 22 is added to each subfield. Assuming that the input image is displayed in 256 gray levels by the subfield method, the bits allocated to each subfield are as follows.

Bit 0 (least significant bit): 1 → 1 + N × A

Bit 1: 2 → 2 + N × B

Bit 2: 4 → 4 + N × C

Bit 3: 8 → 8 + N × D

Bit 4: 16 → 16 + N × E

Bit 5: 32 → 32 + N × F

Bit 6: 64 → 64 + N × G

Bit 7: 128 → 128 + N × H

Here, N represents adjustment variation, and A to H represent correction constants. The reason why the correction constant is different for each bit is that the light emission characteristics of each bit are different.

6 is a block diagram illustrating a driving apparatus of a plasma display device according to another exemplary embodiment of the present invention. In FIG. 6, blocks having the same functions as those of the component blocks shown in FIG. 5 are denoted by the same reference numerals and detailed description thereof will be omitted.

In the configuration of FIG. 6, the driving apparatus of the plasma display device according to the present invention includes a contrast / luminance adjusting unit 22 for converting a change amount of contrast and luminance into digital information according to a user control signal for contrast and luminance adjustment, and an analogue. An A / D converter 24 for digitizing the video signal of the type, and a comparison / determination unit 26 for comparing the contrast / luminance conversion information and the color signal of the input video signal to maintain a white balance value for each color signal. ), An inverse gamma correction unit 6 for inverse gamma correction of the gamma corrected signal to the PDP 21, and a time and space rearrangement for inverse gamma corrected video data to the PDP 21 A multiplexer 8, a memory 10 and a demultiplexer 14, a column driver 18 for supplying digital video data to the X electrode 1 of the PDP 21, and a Y electrode 3 of the PDP 21. ) And a row driver 20 for driving the Z electrode 5. The contrast / luminance adjusting unit 22 is connected to the comparison discriminating unit 26, and when the user adjusts the contrast or brightness, it converts the amount of change into digital information and supplies it to the comparison discriminating unit 26. The A / D converter 24 is connected to the comparison discriminating unit 26 to digitize an analog input video signal and to supply it to the comparing discriminating unit 26. The comparison discriminating unit 26 compares the output signal of the A / D converter 24 with the output signal of the contrast / luminance adjusting unit 22 and corrects the white balance for each color signal to be constant, and reverse-gamma the corrected signal. The correction unit 6, the controller 32, and the row driver 20 are commonly supplied. The control unit 32 controls the number of sustain pulses in each subfield by adjusting the number of sustain pulses necessary for the adjustment in accordance with the contrast / luminance conversion information supplied from the contrast / luminance adjustment unit 22. The row driver 20 adjusts the sustain pulse adjusted by the contrast / luminance change adjusted according to the contrast / luminance information supplied from the comparison discrimination unit 26 under the control of the controller 32 to control the Y electrode 3 and the Y electrode 3. The discharge is supplied to the Z electrode 5 to cause a sustain discharge between the Y electrode 3 and the Z electrode 5. As a result, in the second embodiment of the present invention shown in Fig. 6, the white balance adjustment is performed in the same manner as in the prior art, and the adjustment of the contrast and the brightness is made substantially the same as the first embodiment of the present invention. In the second embodiment of the present invention, when an image is displayed in one frame of 256 gray levels composed of the 0th to 7th sub-fills, the adjustment variation of the number of sustain pulses added or subtracted by the corrected luminance or contrast correction is angulated. It is added to the bits allocated to the subfield.

Bit 0: 1 → 1 + N × (A + a)

Bit 1: 2 → 2 + N × (B + b)

Bit 2: 4 → 4 + N × (C + c)

Bit 3: 8 → 8 + N × (D + d)

Bit 4: 16 → 16 + N × (E + e)

Bit 5: 32 → 32 + N × (F + f)

Bit 6: 64 → 64 + N × (G + g)

Bit 7: 128 → 128 + N × (H + h)

Where N represents the adjustment change, A to H represent the main correction constant, and a to h represent the white balance correction constant.

Unlike the conventional contrast / luminance correction method of correcting contrast and luminance by amplifying an input video signal, the method and apparatus for driving a plasma display device according to the present invention add or decrease the number of sustain pulses by the amount of contrast / luminance change. To adjust the contrast or brightness. Referring to FIG. 7, conventionally, contrast and luminance are adjusted in the adjustment region of the diagonally processed portion, which is an input signal region, so that a margin for luminance / contrast adjustment is required, so that the gray scale level is reduced by the margin. In the present invention, the number of sustain pulses is added or subtracted by the contrast and brightness adjustment changes, thereby adjusting the contrast and the brightness within the blanked adjustment margin area including the diagonally processed portion as the input signal region. The gray scale deterioration of the input signal can be prevented.

As described above, the method and apparatus for driving the plasma display device according to the present invention can adjust the contrast and the luminance without degrading the gray scale, thereby expressing natural colors. The present invention can display the image in full gray scale without increasing the number of bits in the analog / digital conversion it is possible to reduce the manufacturing cost. The present invention can display an image in full gray scale without increasing the subfield, thereby eliminating the problem of luminance deterioration and address time shortening due to the shortening of the light emission period due to the increase of the subfield, and thus it is suitable for high resolution display. Furthermore, the present invention has the advantage that the driving speed does not have to be faster than the conventional driving method in adjusting the contrast and the luminance for the video signal having the same resolution.

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)

Inputting a user control signal; Inputting a video signal, Generating a contrast adjustment value according to the user control signal and converting it into digital information; The contrast is added to the video signal by adding an adjustment variation weight for the number of sustain pulses according to the contrast adjustment value and a correction constant assigned to each bit of the video signal to the number of sustain pulses assigned to each bit of the video signal. Adjusting, Comparing the contrast adjustment value with the video signal, a white balance adjustment value for each color signal included in the video signal is detected, and a white correction constant assigned to each bit of the video signal according to the white balance adjustment value is used for the video signal. And adjusting the white balance by adding to the number of sustain pulses assigned to each bit of the plasma display device. The method of claim 1, Inversely gamma correcting the gamma corrected signal to the display panel; And rearranging the inverse gamma corrected video data to the display panel in a temporally and spatially suitable manner. Inputting a user control signal; Inputting a video signal, Generating a contrast adjustment value according to the user control signal and converting it into digital information; Adjusting the luminance with respect to the video signal by adding or subtracting the number of sustain pulses by the luminance adjustment value; Comparing the brightness adjustment value with the video signal, the white balance adjustment value for each color signal included in the video signal is detected, and the white correction constant assigned to each bit of the video signal is determined according to the white balance adjustment value. And adjusting the white balance by adding to the number of sustain pulses assigned to each bit of the plasma display device. A display panel in which pixel cells are arranged in a matrix form; First input means for inputting a video signal; Second input means input by the user control signal; Contrast adjustment means for inputting the user control signal to convert a contrast adjustment value into digital information according to the user control signal; Comparison discriminating means for comparing the contrast adjustment value with the input video signal to adjust a white balance for each color signal; Control means for controlling the number of sustain pulses by using the output signal of the comparison means; And driving means for generating the sustain pulse under the control of the control means to drive the display panel. The method of claim 11, An analog / digital converting means for digitizing an input video signal; And an inverse gamma correction means for inversely gamma correcting a gamma corrected signal to the display panel. A display panel in which pixel cells are arranged in a matrix form; First input means for inputting a video signal; Second input means input by the user control signal; Brightness adjustment means for inputting a user control signal and converting the brightness adjustment value into digital information according to the user control signal; Comparison discriminating means for comparing the luminance adjustment value with an input video signal to adjust a white balance for each color signal; Control means for controlling the number of sustain pulses by using the output signal of the comparison means; And driving means for generating the sustain pulse under the control of the control means to drive the display panel.