KR20030088295A - Method and apparatus of driving plasma display panel - Google Patents

Abstract

PURPOSE: A method and an apparatus for driving a plasma display panel are provided to enhance the picture quality by performing a gamma correction process after correcting gamma curves of red, green, and blue color data within a predetermined region by means of the average picture level information. CONSTITUTION: A standard gamma correction process for input data is performed by a predetermined mathematical expression(S1). An average picture level of the input data is detected therefrom(S2). Each gamma curve is selected according to kinds of the input data. Each gamma correction region is determined by using the average picture level of the input data(S3). The gamma curve is corrected by converting the corrected region of the selected gamma curve to a predetermined form(S4). The gamma correction processes for red color data, green color data, and blue color data are performed by using the corrected gamma curve(S4).

Description

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

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel, and more particularly, to an apparatus and method for driving a plasma display panel capable of improving image quality.

Plasma Display Panel (hereinafter referred to as "PDP") is a display device using visible light generated from a phosphor when ultraviolet light generated by gas discharge excites the phosphor. PDP is thinner and lighter than Cathode Ray Tube (CRT), which has been the mainstay of display means, and has the advantage of realizing high definition / large screen.

The PDP has an upper substrate and a lower substrate which are installed to face each other with partition walls therebetween. The upper substrate includes first and second electrodes formed in a direction crossing the partition wall. The lower substrate includes an address electrode formed in a direction parallel to the partition wall, and a dielectric layer formed to cover the address electrode. The discharge cell is positioned at the intersection of the address electrode, the first electrode, and the second electrode.

The PDP is driven by dividing one frame into several subfields having different emission counts in order to realize gray levels of an image. Each subfield is divided into a reset period for uniformly causing discharge, an address period for selecting a discharge cell, and a sustain period for implementing gray scale according to the number of discharges.

In the address period, the scan pulse is supplied to the first electrode, and the data pulse synchronized with the scan pulse is supplied to the address electrode. At this time, an address discharge occurs in the discharge cell supplied with the scan pulse and the data pulse. After the scan pulses are supplied to all the first electrodes, the sustain pulses are alternately supplied to the first and second electrodes. When a sustain pulse is supplied to the first and second electrodes, sustain discharge occurs in the discharge cells in which the address discharge has occurred.

When the image is to be displayed in 256 gradations, the frame period (16.67 ms) corresponding to 1/60 second is divided into eight subfields. Here, the reset period and the address period of each subfield are the same for each subfield, while the sustain period and the number of discharges thereof are 2 ⁿ (n = 0,1,2,3,4,5,6,7) in each subfield. , 8). As described above, since the sustain period is changed in each subfield, gray levels of an image can be realized.

1 is a view showing a driving apparatus of a conventional plasma display panel.

Referring to FIG. 1, a conventional PDP driving apparatus includes an inverse gamma correction unit 2, a gain control unit 4, an error diffusion unit 6, and a subfield connected between an input line 1 and a PDP 18. A mapping section 8 and a data sorting section 10; An APL (Avarage Picture Level) unit 14 and a waveform generator 16 connected between the inverse gamma correction unit 2 and the PDP 18 are provided.

The inverse gamma correction unit 2 inversely gamma corrects the gamma corrected video signal and linearly converts a luminance value according to the gray value of the video signal.

The APL unit 14 receives the video data corrected by the inverse gamma correction unit 2 and generates an N-stage signal for adjusting the number of sustain pulses. The gain control section 4 amplifies the video data corrected by the inverse gamma correction section 2 by the effective gain.

The error diffusion unit 6 finely adjusts the luminance value by diffusing an error component of the cell into adjacent cells. The subfield mapping unit 8 reallocates the video data corrected by the error diffusion unit 6 for each subfield.

The data aligning unit 10 converts the video data input from the subfield mapping unit 8 in accordance with the resolution format of the PDP 18 to form an address driving integrated circuit (IC) hereinafter of the PDP 18. Supply).

The waveform generator 16 generates a timing control signal based on the N-stage signal input from the APL unit 14, and converts the generated timing control signal into an address driving IC, a scan driving IC, and a sustain driving IC of the PDP 18. Supply.

However, the conventional PDP driving apparatus has a disadvantage in that it does not dynamically adapt to various input images by applying uniformly the same routine without considering characteristics of different images. In detail, the low gradation portion of the input data passing through the inverse gamma correction unit 2 has its level mapped so low that it has a limit of its expressive power and the contrast decreases in the middle gradation portion. In addition, the high gradation part has a saturation characteristic, which limits the distinction of the gradation.

Accordingly, it is an object of the present invention to provide a method and apparatus for driving a PDP to improve image quality.

1 is a view showing a driving apparatus of a conventional plasma display panel.

2 is a view showing a driving apparatus of a plasma display panel according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating the APL-linked inverse gamma correction unit shown in FIG. 2 in detail.

4 is a flowchart illustrating a control procedure of a method of driving a plasma display panel according to an exemplary embodiment of the present invention.

FIG. 5 is a diagram illustrating an APL curve detected in the APL unit shown in FIG. 2.

6A to 6C are diagrams illustrating a corrected gamma curve in each region according to the APL curve shown in FIG. 5.

<Description of Symbols for Main Parts of Drawings>

1,21: input line 2,46: inverse gamma correction unit

4,24: gain control section 6,26: error diffusion section

8,28: subfield mapping unit 10,30: data alignment unit

14,36: APL section 16,38: waveform generation section

18,32: PDP22: APL interlocking gamma correction unit

34: standard gamma correction unit

40: Image data classification and compensation area setting unit

42: gamma curve selection unit

44: gamma curve conversion unit for the compensation region

In order to achieve the above object, the driving method of the PDP according to the embodiment of the present invention comprises the steps of detecting the average brightness of the input data, selecting a gamma curve according to the type of the data, and the average brightness of the data Setting a gamma compensation region according to the present invention, converting the gamma compensation region of the selected gamma curve into a predetermined form, and correcting a gamma curve; and gamma correcting red, green, and blue data according to the corrected gamma curve, respectively. Characterized in that it comprises a step.

The setting of the gamma compensation region according to the average brightness of the data in the present invention may be performed by classifying the gamma compensation region according to the classified gradation levels as well as classifying the low gradation, mid gradation and high gradation levels according to the average brightness. Characterized in that the step.

In the present invention, the method may further include controlling a gain of the gamma corrected data and error diffusing the data whose gain is controlled.

An apparatus for driving a plasma display panel according to an exemplary embodiment of the present invention includes an average image level controller for detecting average brightness of input data and determining a discharge frequency according to the average brightness of the data, and input data according to the detected average brightness information. And a gamma correction unit for linearly correcting the gamma curve in the corresponding gray level region, and a gamma correction unit for gamma correcting the data according to the corrected gamma curve.

The present invention may further include a standard gamma adjustment unit configured to standard gamma correct the red, green, and blue data to a gamma correction value set to the same value.

The average image level control unit of the present invention is characterized by detecting the average brightness with respect to the standard gamma corrected data.

The detected average brightness information in the present invention is characterized by low, medium and high gradations according to the gradation level of the average brightness.

In the present invention, the low gray average brightness level is 0 to 41, the mid gray average brightness level is 41 to 101, and the high gray average brightness level is 101 to 255.

Other objects and features of the present invention in addition to the above object 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. 2 to 6C.

2 is a block diagram illustrating a driving device of a PDP according to an embodiment of the present invention.

Referring to FIG. 2, an apparatus for driving a PDP according to an exemplary embodiment of the present invention may include an APL (Avarage Picture Level) interlocking gamma correction unit 22 connected between an input line 21 and a PDP 32. A gain control section 24, an error diffusion section 26, a subfield mapping section 28, and a data sorting section 30; A standard gamma correction unit 34 for performing standard gamma correction on data from the input line 21; A standard gamma correcting section 34, a discharge frequency-linked reverse gamma correcting section 22, and an APL (Avarage Picture Level) section 36 and a waveform generating section 38 connected between the panel are provided.

APL (Avarage Picture Level) interlocking gamma correction unit 22 is a gamma correction value in which a corresponding region of a gamma correction curve is adjusted according to APL information input from the APL unit 36. By gamma correction, the luminance value according to the gray value of the video signal is linearly converted. The APL-linked inverse gamma correction unit 22 includes an image data classification and compensation region setting unit 40 connected to the input line 21, a gamma curve conversion unit 44 for the set compensation region, and the like. And an inverse gamma correction unit 46 for gamma correcting the input data according to the converted gamma curve, and between the image data classification and compensation area setting unit 40 and the gamma curve conversion unit 44 for the set compensation area. A gamma curve selecting section 42 is provided. The image data classification and compensation area setting unit 40 receives input data from the input line 21 and APL information from the APL unit 34. For this reason, this classifies the data for the corresponding color and sets the gamma correction value compensation area according to the APL information.

The gamma curve selector 42 selects a corresponding gamma correction curve from the image data classified by the image data classification and compensation region setting unit 40 and APL information, and supplies it to the gamma curve conversion unit 44 for the compensation region. do.

The gamma curve converter 44 for the compensation region receives a gamma curve suitable for the compensation region and the input image from the image data classification and compensation region setting unit 40 and the gamma curve selector 42. Is converted into a predetermined form.

The inverse gamma corrector 46 gamma-corrects the input data through the gamma curve compensated by the gamma curve converter 44 for the compensation region, and linearly converts a luminance value according to the gray value of the image signal.

The gain control unit 24 multiplies the red, green, and blue video data corrected by the APL-linked inverse gamma adjustment unit 22 by a value that can be adjusted by a user or a set maker to red, green. And the gain is adjusted for each blue. The gain control section 24 allows the user or set maker to set the desired color temperature.

The error diffusion unit 26 finely adjusts the luminance value by diffusing an error component to adjacent cells with respect to the data from the gain control unit 24.

The subfield mapping unit 28 maps the data input from the error diffusion unit 26 to a preset subfield pattern and supplies the data to the data alignment unit 30.

The data aligning unit 30 converts the video data input from the subfield mapping unit 28 to suit the resolution format of the PDP 32 so that the address driving integrated circuit (IC) of the PDP 32 is referred to as " IC " Supply).

The standard gamma correction unit 34 performs inverse gamma correction on the red, green, and blue video data by the gamma power as shown in Equation (1).

The APL unit 36 receives the video data corrected by the standard gamma correction unit 34 and generates an N-stage signal for adjusting the number of sustain pulses. At this time, the APL unit 36 supplies the APL information to the APL-linked inverse gamma correction unit 22.

The waveform generator 38 generates a timing control signal based on the N-stage signal input from the APL unit 36, and converts the generated timing control signal into an address driving IC, a scan driving IC, and a sustain driving IC of the PDP 32. Supply.

4 is a flowchart illustrating a control procedure of the PDP driving method according to the present invention through the configuration as described above.

Referring to FIG. 4, the driving method of the PDP according to the embodiment of the present invention performs the standard gamma correction on the input data using Equation 1 and detects the average brightness of the input data, that is, APL as shown in FIG. 5. (S1 and S2) All input data is calculated with average brightness and mapped to any one of 256 APL levels, and the number of discharges to be used in the input frame is allocated according to the APL level.

According to the detected APL, the PDP driving method of the present invention sets the gamma curve compensation area and corrects the gamma curve in the compensation area. (S3) In FIG. 5, (A) areas (0 to 41), That is, when the APL level is low, the gamma curve of the low gray level is corrected as shown in FIG. 6A. A low APL level here means that there are many dark pixels in the input frame on average. In FIG. 5, when the regions 41 to 101, that is, the APL level is about medium, the gamma curve of the gray scale is corrected as shown in FIG. 6B. In FIG. 5, when the (C) areas 101 to 255, that is, the APL level is high, the entire gray level needs to be considered, the gamma curve of the low gray level is corrected as shown in FIG. 6C. Gamma correction is performed for each of red, green, and blue colors according to the corrected gamma curve. (S4) Then, in order to adjust the color temperature, the driving method of the PDP according to the embodiment of the present invention controls the gain for each of the red, green, and blue colors. (S5)

As described above, the method and apparatus for driving a plasma display panel according to the present invention perform gamma correction after correcting gamma curves of red, green, and blue data in a predetermined area according to average image brightness information. As a result, the method and apparatus for driving a PDP according to the present invention can improve image quality by compensating for the gray level of the input data according to the data even when the gray level of the input data is different.

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)

Detecting an average brightness of the input data; Selecting a gamma curve according to the type of data; Setting a gamma compensation region according to the average brightness of the data; Correcting the gamma curve by converting the gamma compensation region of the selected gamma curve into a predetermined shape; And gamma correcting the red, green, and blue data, respectively, according to the corrected gamma curve. The method of claim 1, The step of setting the gamma compensation region according to the average brightness of the data is a step of classifying the low, middle and high gray levels according to the average brightness and setting the gamma compensation area according to the classified gray levels. A method of driving a plasma display panel. The method of claim 1, Controlling gain of the gamma corrected data; And spreading an error on the gain-controlled data. An average image level control unit for detecting an average brightness of input data and determining a discharge frequency according to the average brightness of the data; A gamma curve correction unit linearly correcting a gamma curve in a corresponding gray level region with respect to input data according to the detected average brightness information; And a gamma correction unit configured to gamma correct the data according to the corrected gamma curve. The method of claim 4, wherein And a standard gamma adjusting unit configured to standard gamma correct the red, green, and blue data to a gamma correction value set to the same value. The method of claim 5, And the average image level control unit detects average brightness with respect to the standard gamma corrected data. The method of claim 4, wherein And the detected average brightness information is low gray, mid gray and high gray according to the gray level of the average brightness. The method of claim 7, wherein The low gray average brightness level is 0 to 41, The gray level average brightness level is 41 to 101, The high gray average brightness level is 101 to 255 drive device of the plasma display panel. The method of claim 4, wherein A gain controller for adjusting the gain of the gamma corrected data; And an error diffusion unit for error diffusion of the gain-controlled data.