KR100551122B1 - Apparatus and Method of Driving Plasma Display Panel - Google Patents

Abstract

The present invention relates to an apparatus for driving a plasma display panel to minimize signal distortion.

The apparatus for driving a plasma display panel according to the present invention includes a first gamma adjusting unit for correcting first inverse gamma correction, a gray level processing unit for performing gray level processing using the first inverse gamma adjusted data, and a gray level processing. And a second gamma adjustment unit for adjusting the second inverse gamma.

Description

Driving apparatus and driving method of plasma display panel {Apparatus and Method of Driving Plasma Display Panel}             

1 is a perspective view showing a conventional three-electrode AC surface discharge type plasma display panel.

2 shows one frame of a plasma display panel;

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

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

<Description of Symbols for Main Parts of Drawings>

1: front glass substrate 2: rear glass substrate

3: bulkhead 4: address electrode

5: phosphor 6,7: dielectric layer

8: protective film 9: top electrode

30,40,44: Gamma adjustment part 32,42: Error diffusion & dither processing part

33,46: subfield mapping unit 34,48: data driver

35, 52: scan driver 36, 54: sustain driver

37,50: Plasma Display Panel

The present invention relates to a driving apparatus and a driving method of a plasma display panel, and more particularly, to a driving apparatus and a driving method of a plasma display panel to minimize signal distortion.

As the information processing system develops and its spread is expanded, the importance of the display device as a means of transmitting visual information is increasing. Cathode ray tubes (CRTs), which dominate the display device, have large size, high operating voltage, and display distortion. Recently, liquid crystal displays (LCDs), field emission displays (FEDs), and plasma display panels (hereinafter referred to as "PDPs") can solve the disadvantages of cathode ray tubes. Flat panel display devices are being developed.

The PDP displays an image by excitation of phosphors by vacuum ultraviolet rays generated when the inert gas is discharged. Such a PDP is not only thin and large in size, but also simple in structure, and has a high luminance and high luminous efficiency as compared to other flat display devices. In particular, the AC surface discharge type PDP has advantages of low voltage driving and long life because wall charges are accumulated on the display surface and protect the electrodes from sputtering caused by the discharge.

Referring to FIG. 1, an AC surface discharge type PDP includes a front glass substrate 1 on which an upper electrode 9 is formed, and a back glass substrate 2 on which an address electrode 4 is formed.

The front glass substrate 1 and the rear glass substrate 2 are spaced apart in parallel with the partition 3 therebetween. A mixed gas such as Ne + Xe, He + Xe, He + Ne + Xe is injected into the discharge space provided by the front glass substrate 1, the rear glass substrate 2, and the partition wall 3. The upper electrode 9 is paired with two in one plasma discharge channel. Each of the upper plate electrodes 9 includes a wide transparent electrode and a narrow metal bus electrode connected to one side edge of the transparent electrode. Any one of the pair of top electrodes 9 causes an opposite discharge with the address electrode 4 in response to the scan pulse supplied in the address period, and then the adjacent top electrodes 9 in response to the sustain pulse supplied in the sustain period. ) And a scan electrode causing surface discharge. The other upper electrode 9 paired with the scan electrode is a sustain electrode to which a sustain pulse is commonly supplied.

The top dielectric layer 7 and the passivation layer 8 are stacked on the front glass substrate 1 on which the top electrodes 9 are formed. The upper dielectric layer 7 serves to limit the discharge current during plasma discharge and to accumulate wall charges during discharge. The protective film 8 is usually made of magnesium oxide (MgO), and prevents damage to the top dielectric layer 7 caused by sputtering generated during plasma discharge and improves the emission efficiency of secondary electrons.

A lower dielectric layer 6 is formed on the rear glass substrate 2 to cover the address electrodes 4. The lower dielectric layer 6 serves to protect the address electrodes 4. On the lower dielectric layer 6, partition walls 3 for dividing the discharge space are formed. On the surfaces of the lower dielectric layer 6 and the partition walls 3, phosphors 5 are excited by vacuum ultraviolet rays to generate visible light of red, green, and blue (R, G, B).

The discharge mechanism of the PDP is as follows. When a voltage is applied between two electrodes of the PDP, a potential is formed in the discharge space, and a potential is generated in the pixel as the gas atoms and molecules collide with each other and ionization proceeds. The charged particles generated by the gas discharge are accumulated on the surface of the dielectric layer 7 according to the polarity of the electrode. The negative and positive charges accumulated on the surface of the dielectric layer 7 are called wall charges, and the voltage of the pixel charged by the wall charges is called a wall voltage. If the polarity of the wall charge sufficiently accumulated on the surface of the dielectric layer 7 is opposite to the polarity of the external voltage applied to the electrode, the discharge is erased while the wall voltage and the external voltage are canceled out. When the polarities of the external voltages are reversed and the polarities of the wall voltages and the external voltages are the same, the total voltage applied to the discharge space is the sum of the external voltages and the wall voltages. .

The PDP is time-divisionally driven in a so-called ADS (Address and Display Seperated) method, which is divided into an address period for selecting a pixel and a sustain period for causing display discharge in the selected pixel, in order to realize the gradation of the image. That is, one frame period is divided into several subfields having different sustain discharge times according to the luminance weight, and each subfield is divided into a reset period, an address period, and a sustain period. For example, when the image is to be displayed with 256 gray levels, a frame period (16.67 ms) corresponding to 1/60 second is divided into eight subfields SF1 to SF8 as shown in FIG. As described above, each of the eight subfields SF1 to SF8 is divided into a reset period, an address period, and a sustain period. The reset period and the address period of each subfield are the same for each subfield, while the sustain period and the number of sustain pulses allocated thereto are 2 ⁿ (n = 0,1,2,3,4,5,6) in each subfield. , 7).

3 is a block diagram schematically illustrating a PDP and a driving device thereof. In fact, the PDP further includes various driving units in addition to the driving units shown in FIG. 3. Here, only the critical driver will be shown for convenience of description.

Referring to FIG. 3, a conventional PDP apparatus includes a gamma adjusting unit 30, an error diffusion & dither processing unit 32, a subfield mapping unit 33, and a data driver 34 connected between an input line and a PDP 37. ). The PDP 37 includes a sustain electrode pair (i.e., top electrodes 9) including a scan electrode and a sustain electrode, and an address electrode intersecting the sustain electrode pair. Discharge cells are arranged in a matrix at the intersection of the sustain electrode pair and the address electrodes.

Video data R, G, and B supplied from the outside are input to the subfield mapping unit 33 through the gamma adjusting unit 30 and the error diffusion & dither processing unit 32.

The gamma adjuster 30 inversely gamma corrects red, green, and blue video data to linearly convert luminance values according to grayscale values of the video data. For example, the gamma adjusting unit 30 divides the current input value by the highest input value and then corrects the data by 2.2 gamma-squared.

The error diffusion & dither processing unit 32 uses the Floyd-Steinberg error diffusion filter to add the quantization error components of the digital video data R, G, and B input from the gamma adjustment unit 30 to adjacent pixels. Diffusion reduces quantization errors and refines gradation expression. In addition, the error diffusion & dither processing unit 32 thresholds the input data with a dither mask (or dither matrix) having a threshold set corresponding to each pixel.

The subfield mapping unit 33 maps the data from the error diffusion & dither processing unit 32 to a preset subfield pattern.

The data driver 34 latches data from the subfield mapping unit 33 and supplies the latched data to the address electrodes of the PDP 37 by one line every one horizontal period.

The scan driver 35 is connected to the scan electrodes of the PDP 37 to supply the necessary signals to the scan electrodes to drive the scan electrodes.

The sustain driver 36 is connected to the sustain electrode of the PDP 37 to supply the necessary signal to the sustain electrode to drive the sustain electrode.

However, such a conventional PDP driving device causes distortion of the original signal. In detail, first, externally input video data R, G, and B are inversely gamma corrected by the gamma adjusting unit 30. Thereafter, the inverse gamma corrected data are gradated to be displayed on the PDP 37 and supplied to the PDP 37. In this case, the data used in the gradation process uses inverse gamma corrected data different from the original signal (the original data), that is, the gradation process is performed using the data different from the original data. That is, a slight difference occurs with the image to be displayed in the original data). Substantially, when the grayscale processing is performed by using the gamma corrected data using the 2.2 gamma curve, the expressive power of the low grayscale is lowered.

Accordingly, an object of the present invention is to provide a driving apparatus and a driving method of a plasma display panel which can minimize signal distortion.

In order to achieve the above object, a driving apparatus of a plasma display panel according to the present invention includes a first gamma adjusting unit for correcting first inverse gamma correction of data input from the outside and a gray level for performing gray level processing using the first inverse gamma adjusted data. And a second gamma adjustment unit for correcting the second inverse gamma of the grayscaled data.

The second gamma adjusting unit corrects inverse gamma using a higher gamma value than the first gamma adjusting unit.

The first gamma adjusting unit corrects the first inverse gamma to 1.1 to 1.2 gamma values.

The gamma value of the second gamma adjustment unit is set such that the inverse gamma correction value of the first gamma adjustment unit and its inverse gamma correction value are summed to be inversely gamma adjusted to 2.2 gamma.

The gradation processor includes at least one of an error diffusion unit for error diffusion and a dither processor for dithering.

The apparatus for driving a plasma display panel according to the present invention includes a first gamma adjusting unit for correcting first inverse gamma correction, a gray level processing unit for performing gray level processing using the first inverse gamma adjusted data, and a gray level processing. A subfield mapping unit for mapping data according to the subfield pattern and correcting the second inverse gamma is provided.

The subfield mapping unit corrects inverse gamma using a gamma value higher than that of the first gamma adjusting unit.

The first gamma adjusting unit corrects the first inverse gamma to 1.1 to 1.2 gamma values.

The gamma value of the subfield mapping unit is set such that the inverse gamma correction value of the first gamma adjustment unit and its inverse gamma correction value are summed to be inversely gamma adjusted to 2.2 gamma.

The gradation processor includes at least one of an error diffusion unit for error diffusion and a dither processor for dithering.

According to an exemplary embodiment of the present invention, a method of driving a plasma display panel includes performing first inverse gamma correction on data input from the outside, gradation processing on the first inverse gamma data, and second inverse gamma correction on the grayscale data. It includes.

In the second inverse gamma correction step, inverse gamma correction is performed using a higher gamma value than the first inverse gamma correction step.

In the first inverse gamma correction step, inverse gamma correction is performed on data input from the outside to 1.1 to 1.2 gamma values.

The second inverse gamma correction step is combined with an inverse gamma correction value of the first inverse gamma correction step so as to perform inverse gamma correction so that data input from the outside can be inverse gamma corrected by 2.2 gamma.

In the gradation processing step, gradation processing is performed using at least one processing method of error diffusion processing and dithering processing using the first inverse gamma corrected data.

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, a preferred embodiment of the present invention will be described with reference to FIG. 4.

4 is a view showing a driving apparatus of a plasma display panel according to an embodiment of the present invention. In fact, the PDP further includes various driving units in addition to the driving units shown in FIG. 4. Here, only the critical driver will be shown for convenience of description.

Referring to FIG. 4, the driving apparatus of the PDP of the present invention includes a first gamma adjusting unit 40, an error diffusion & dither processing unit 42, a second gamma adjusting unit 44 connected between the input line and the PDP 50. The subfield mapping unit 46 and the data driver 48 are provided.

The PDP 50 includes a sustain electrode pair including a scan electrode and a sustain electrode, and an address electrode intersecting the sustain electrode pair. Discharge cells are arranged in a matrix at the intersection of the sustain electrode pair and the address electrodes. The video data R, G, and B supplied from the outside are subjected to gradation processing (performed by the error diffusion & dither processing unit 42) via the first gamma adjustment unit 40, and then the second gamma adjustment unit 44 and subfield mapping. It is supplied to the address electrodes of the PDP 50 via the unit 46 and the data driver 48.

The first gamma adjusting unit 40 corrects the first inverse gamma of the red, green, and blue video data (R, G, B). Here, the first gamma adjusting unit 40 gammaes 1.1 to 1.2 of the original data R, G, and B so that distortion of the original data R, G, and B supplied from the input line may be minimized. In other words, the first gamma adjusting unit 40 performs reverse gamma correction on the original data R, G, and B in a range in which distortion of the original data R, G, and B can be prevented.

The error diffusion & dither processing unit 42 spreads the error value of the data corresponding to the gray level to the adjacent pixels to reduce the quantization error and to finely express the gray level. In addition, the error diffusion & dither processing unit 42 thresholds the input data with a dither mask (or dither matrix) having a threshold set corresponding to each pixel. On the other hand, for the convenience of explanation, the error diffusion and dithering processing is performed at the same time. However, in the present invention, only one of the error diffusion & dithering processing can be performed.

The grayscale data R, G, and B processed by the error diffusion and dither processing unit 42 are input to the second gamma adjusting unit 44. The second gamma adjusting unit 44 corrects the second inverse gamma of the grayscaled data R, G, and B. (At this time, the second gamma adjusting unit 44 uses a higher gamma value than the first gamma adjusting unit 40. To compensate for the second inverse gamma. In this case, the second gamma adjusting unit 44 adjusts the gray scaled data R, G, and B to be 2.2 gamma in combination with the inverse gamma correction value of the first gamma adjusting unit 40. The second inverse gamma correction is performed. In other words, the inverse gamma correction value of the second gamma adjustment unit 44 is set such that the gamma adjustment value of the original data R, G, and B can be 2.2 gamma.

Meanwhile, in the present invention, the second inverse gamma correction may be performed by the subfield mapping unit 46. In other words, in the present invention, the second field gamma adjustment may be performed by the subfield mapping unit 46 on the data R, G, and B grayscale processed by the error diffusion and dither processing unit 42 without the second gamma adjustment unit 44. have.

In the present invention as described above, the first inverse gamma correction is performed so that the data input from the outside is not distorted (or minimized), and gradation processing is performed using the first inverse gamma corrected data. Therefore, in the driving apparatus of the PDP of the present invention, distortion of the original signal can be minimized, so that the same image as the original data can be displayed on the PDP 50. In other words, since the first inverse gamma corrected data similar to the original signal (raw data) is used for the gradation processing, the data with minimal distortion is used for the gradation processing, so that the image is accurately displayed on the PDP 50 for display. Can be displayed.

The subfield mapping unit 46 maps data from the second gamma adjusting unit 44 to a preset subfield pattern. Here, the subfield mapping unit 46 may correct the second inverse gamma of the grayscaled data input from the error diffusion and dither processing unit 42. (At this time, the second gamma adjustment unit 44 is removed.)

The data driver 48 latches data from the subfield mapping unit 46 and supplies the latched data to the address electrodes of the PDP 50 by one line every one horizontal period.

The scan driver 52 is connected to the scan electrodes of the PDP 50 to supply the necessary signals to the scan electrodes to drive the scan electrodes.

The sustain driver 54 is connected to the sustain electrode of the PDP 50 to supply a necessary signal to the sustain electrode to drive the sustain electrode.

As described above, according to the driving apparatus and driving method of the plasma display panel according to the present invention, since the gradation processing is performed using the first inverse gamma corrected data with 1.1 to 1.2 gamma, distortion of the original data can be minimized. . In addition, since the second inverse gamma correction is performed so that the total inverse gamma correction value of the grayscale data is 2.2 gamma, and the second inverse gamma correction data is supplied to the panel, an image without distortion of the original data is displayed on the panel. can do.

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 (15)

A first gamma adjusting unit for correcting first reverse gamma correction of data input from the outside; A gradation processing unit which performs gradation processing using the first inverse gamma adjusted data; And a second gamma adjustment unit for correcting the second inverse gamma correction using a gamma value higher than that of the first gamma adjustment unit. delete The method of claim 1, And the first gamma adjusting unit corrects the first inverse gamma of the input data by 1.1 to 1.2 gamma values. The method of claim 3, wherein And a gamma value of the second gamma adjustment unit is set such that an inverse gamma correction value of the first gamma adjustment unit and its inverse gamma correction value are combined so as to be inversely gamma adjusted to 2.2 gamma. The method of claim 1, And the gradation processor comprises at least one of an error diffusion unit that performs error diffusion and a dither processing unit that performs dithering. A first gamma adjusting unit for correcting first reverse gamma correction of data input from the outside; A gradation processing unit which performs gradation processing using the first inverse gamma adjusted data; And a subfield mapping unit for mapping the grayscale data according to a predetermined subfield pattern and correcting a second inverse gamma using a gamma value higher than that of the first gamma adjusting unit. Device. delete The method of claim 6, And the first gamma adjusting unit corrects the first inverse gamma of the input data by 1.1 to 1.2 gamma values. The method of claim 8, The gamma value of the subfield mapping unit is set such that an inverse gamma correction value of the first gamma adjustment unit and an inverse gamma correction value of the subfield mapping unit are adjusted so as to be inversely gamma adjusted to 2.2 gamma. The method of claim 6, And the gradation processor comprises at least one of an error diffusion unit that performs error diffusion and a dither processing unit that performs dithering. First inverse gamma correction of data input from the outside; Gradation processing the first inverse gamma data; And performing a second inverse gamma correction on the grayscale data using a higher gamma value than the first inverse gamma correction step. delete The method of claim 11, In the first reverse gamma correction step, the inverse gamma correction of data input from the outside to a gamma value of 1.1 to 1.2 is performed. The method of claim 13, The second inverse gamma correction step is performed by adding the inverse gamma correction value of the first inverse gamma correction step to inverse gamma correction so that data input from the outside can be inversely gamma corrected by 2.2 gamma. Driving method. The method of claim 11, The gradation processing step includes the gradation processing using at least one processing method of error diffusion processing and dithering processing using the first inverse gamma corrected data.

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