KR20060015017A - Driving method of plasma display panel and plasma display device - Google Patents

Abstract

In the plasma display panel, image data is mapped to N subfields, and the subfield having the highest weight among the mapped subfields is determined. In the case where the highest weighted subfield is a Kth subfield larger than M, the mapping data of the (K-M + 1) th to Kth subfields is processed as valid data, and the first to (KM) th subfields are processed. Treat mapping data as invalid data. At this time, the invalid data is determined according to the subfield data of the first discharge cell having valid data among the discharge cells scanned immediately before and the discharge cells scanned later. In this way, an increase in power consumption in the address period can be prevented even when the number of subfields allocated to one field increases.

PDP, subfield, gradation, power consumption, masking

Description

Driving method of plasma display panel and plasma display device {DRIVING METHOD OF PLASMA DISPLAY PANEL AND PLASMA DISPLAY DEVICE}

1 is a schematic diagram of a plasma display device according to an exemplary embodiment of the present invention.

FIG. 2 is a detailed block diagram illustrating a controller of the plasma display panel of FIG. 1.

3 is a diagram illustrating subfield masking according to a first embodiment of the present invention.

4 is a flowchart illustrating a method of processing invalid data according to a second embodiment of the present invention.

5 is a diagram illustrating data determined according to the method of FIG. 4.

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

The plasma display device is a display device using a plasma display panel that displays text or an image by using plasma generated by gas discharge. In the plasma display panel, dozens to millions or more pixels (discharge cells) are arranged in a matrix form according to their size. The plasma display panel is classified into a direct current type (DC type) and an alternating current type (AC type) according to the shape of the driving voltage waveform applied and the structure of the discharge cell.

Generally, in an AC plasma display panel, one field (1TV field) is divided into a plurality of subfields having respective weights and driven, and the gray level is displayed by the sum of the weights of the subfields in which the display operation occurs among the plurality of subfields. do. For example, in the case of using a weighted subfield in the form of a power of 2, pseudo contours occur when one discharge cell expresses 127 gray levels and 128 gray levels, respectively, in two consecutive frames. As described above, in the subfield having a weight of power of 2, pseudo contours may be generated by subfields having a large weight, so that subfields having a large weight are reduced by increasing the number of subfields.

In addition, in order to increase the expressive power of gradation, it is necessary to increase the number of subfields. For example, in order to express 512 gradations, the number of subfields should be set to about 14. However, each subfield has an address period for selecting a discharge cell to emit light in the corresponding subfield. In this address period, a number of switching operations are performed to select discharge cells to emit light, and thus power consumption is generated due to switching, and since address discharge occurs in the selected discharge cells, power consumption is also generated according to address discharge. However, as the number of subfields increases, the number of address periods increases, resulting in an increase in power consumed in the address period.

An object of the present invention is to provide a method of driving a plasma display panel which can increase the number of subfields without increasing power consumption in an address period.

In order to solve this problem, the present invention processes only some subfield data among the plurality of subfields as valid data.

According to one aspect of the present invention, in a plasma display panel in which a plurality of discharge cells are formed in a matrix form, one field is divided into N (N is a natural number) subfields having respective luminance weights, and the N subfields are divided. A method of driving a plasma display panel in which gray levels are represented by a sum of weights of subfields to which image data is mapped is provided. The driving method of the present invention includes a first step of mapping input image data into the N subfields, and M (M is a natural number smaller than N) subfields of the image data mapped to the N subfields. The second step of setting the valid data corresponding to the step, and if the invalid data exist after setting the valid data for the image data of the first discharge cell, is located on the same line as the first discharge cell and the first And setting the invalid data according to the data of the second discharge cell scanned in time previously with respect to the first discharge cell and the third discharge cell scanned in time later with respect to the first discharge cell.

According to an embodiment of the present invention, when arranging the N subfields in luminance weight order, the subfield having the highest weight among the subfields to which the image data is mapped in the first step is K (K is larger than M). Natural video), the video data mapped from the (K-M + 1) th to the Kth subfield is set as valid data, and the data of the first to (KM) th subfield is invalid. Set with data.

According to another embodiment of the present invention, among the invalid data of the first to (KM) th subfields for the first discharge cell, i (i is an integer between 1 and (KM)) th invalid data of the Valid data of the i-th subfield of the second discharge cell and valid data of the i-th subfield of the third discharge cell are determined.

According to another embodiment of the present invention, when the data of the i th subfield for the second discharge cell and the third discharge cell are the same, the invalid data of the i th subfield for the first discharge cell is Data of the i th subfield for the second discharge cell and the third discharge cell are set.

According to another embodiment of the present invention, when data of the i-th subfield for the second discharge cell and the third discharge cell are different, invalid data of the i-th subfield for the first discharge cell is Maintain original data of the first discharge cell.

According to another feature of the present invention, a plasma display panel in which a plurality of discharge cells are arranged in a matrix form, a driver for applying a drive signal to the discharge cells, and one field are divided into N subfields having respective luminance weights. And a control unit for controlling the driving unit to map image data of each discharge cell to the subfields and to express gray levels with the data mapped to the subfields. The control unit, when the image data for the first discharge cell uses the K-th sub-field after the M-th when the N sub-fields are arranged in the order of the luminance weight, the first control unit for the first discharge cell The data of the (KM) th subfield is set according to the data of the discharge cells respectively scanned before and after the time with respect to the first discharge cell.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention. Like parts are designated by like reference numerals throughout the specification.

1 is a schematic diagram of a plasma display device according to an exemplary embodiment of the present invention.

As shown in FIG. 1, a plasma display device according to an exemplary embodiment of the present invention includes a plasma display panel 100, a controller 200, an address driver 300, an X electrode driver 400, and a Y electrode driver 500. Include.

The plasma display panel 100 includes a plurality of address electrodes A1 to Am extending in the column direction, and a plurality of X electrodes X1 to Xn and Y electrodes Y1 to Yn extending in pairs in the row direction. Include. The X electrodes X1 to Xn are formed corresponding to the respective Y electrodes Y1 to Yn, and generally have one end connected in common to each other. The plasma display panel 100 includes a glass substrate (not shown) in which X and Y electrodes X1 to Xn and Y1 to Yn are arranged, and a glass substrate (not shown) in which address electrodes A1 to Am are arranged. Is done. The two glass substrates are disposed to face each other with discharge spaces interposed so that the Y electrodes Y1 to Yn and the address electrodes A1 to Am and the sustain electrodes X1 to Xn and the address electrodes A1 to Am are orthogonal to each other. At this time, the discharge space at the intersection of the address electrodes A1 to Am and the X and Y electrodes X1 to Xn and Y1 to Yn forms a discharge cell.

The controller 200 selects a subfield in which the discharge cells are turned on from among a plurality of subfields according to a gray level input from the outside, and outputs an address driving control signal, an X electrode driving control signal, and a Y electrode driving control signal. The address driver 300, the X electrode driver 400, and the Y electrode driver 500 receive driving control signals from the controller 200, and address electrodes A1 to Am and X electrodes X1 to X in each subfield. A driving voltage is applied to Xn and Y electrodes Y1 to Yn, respectively.

Next, the controller 500 of the plasma display device according to the first embodiment of the present invention will be described in detail with reference to FIGS. 2 and 3. 2 is a detailed block diagram of the controller 200 of FIG. 1.

2, the control unit 200 includes an inverse gamma correction unit 210, an error diffusion unit 220, an APC control unit 230, a sustain discharge pulse control unit 240, and a subfield data generation unit 250. .

The inverse gamma correction unit 210 generates the image data by inversely gamma correcting the image signal input from the outside. In practice, the inverse gamma correction unit 210 changes the gray level of the image signal input from the outside using a lookup table (not shown) that stores data corresponding to the inverse gamma characteristic curve. The error diffusion unit 220 increases the expressive power of the gray level by diffusing some bits of the image data corrected by the inverse gamma correction unit 210 to adjacent pixels. The inverse gamma correction unit 210 and the error diffusion unit 220 may not be used in the control unit 200.

The APC controller 230 detects a screen load ratio from the image data output from the error diffusion unit 220 and calculates an automatic power control (APC) level corresponding to the detected load ratio. For example, the APC controller 230 calculates the screen load ratio from the average signal level of the image data corresponding to one field, and when the screen load ratio is high, reduces the total number of sustain discharge pulses used in the sustain period to reduce power consumption. Restrict. The sustain discharge pulse controller 240 controls the X electrode driver 400 and the Y electrode driver 500 to supply the number of sustain discharge pulses corresponding to the APC level input from the APC controller 230.

The subfield data generator 250 maps the image data output from the error diffusion unit 220 into a plurality of subfields, and then transfers the mapped subfield data to the address driver 300. Then, the address driver 300 applies an address voltage for selecting a discharge cell to emit light for each subfield according to the subfield data to the address electrode. At this time, the subfield data generation unit 250 determines M subfields to be used for gray scale representation among the N subfields according to the grayscale value of the input image data (M <N).

Next, the operation of the control unit 200, in particular, the operation of the subfield data generation unit 250 will be described in detail with reference to FIG. 3.

3 is a diagram illustrating subfield masking according to a first embodiment of the present invention. In FIG. 3, for convenience of description, one field is composed of 14 subfields capable of expressing 512 gray levels, and the luminance weights of the 14 subfields are 1, 2, 3, 4, 6, 9, 13, 19, 28, 41, 62, 85, 108 and 131. Fourteen weights are arranged in the order of the magnitude of the luminance weight, so that the weight of the first subfield is 1 and the weight of the 14th subfield is 131. In this case, in the case where 335 gray levels are expressed, data of "00110110101101" is mapped to 14 subfields in order. Here, '0' indicates no light emission in the corresponding subfield and '1' indicates light emission in the corresponding subfield.

The subfield data generation unit 250 determines a subfield having the highest weight among 14 subfields while mapping the gray level of the input image data into 14 subfields. In FIG. 3, for example, if the input gray level is 4, the third subfield is the highest weight subfield, if the input gray level is 35, the eighth subfield, and if the input gray levels are 206 and 207, the 12th subfield is the highest weight subfield. Field. As described above, if the highest weight subfield is the 12th or less subfield, the 13th and 14th subfields are not used, and thus, the subfield data generator 250 maps the image data into the 1st to 12th subfields.

For example, when the input gray levels are 314 and 315, the thirteenth subfield is the highest weight subfield. If the subfield having the highest weight is the thirteenth subfield, the subfield data generation unit 250 maps the image data to only the second to thirteenth subfield, and ignores data corresponding to the first subfield. That is, since 314 and 315 are mapped only to the second to thirteenth subfields, 314 and 315 are represented by the same gray level of 314.

Next, for example, if the input gray levels are 335, 336, 337, and 338, the 14th subfield is the highest weight subfield. If the highest weighted subfield is the 14th subfield, the subfield data generator 250 maps the image data only to the 3rd to 14th subfields, and ignores data corresponding to the 1st and 2nd subfields. do. That is, since 335, 336, 337, and 338 are mapped only to the 3rd to 14th subfields, they are expressed by the same gray level of 335.

In summary, in the first embodiment of the present invention, the input image data is represented by only M subfields among N subfields. At this time, when the input image data uses the K-th subfield in the order of the luminance weight (K> M), the data corresponding to the 1st to (K-M) th subfields are ignored and processed as invalid data. In this way, since all the image data is represented by only j subfields, the number of address periods is reduced compared to the case of expressing grayscales using M subfields, thereby reducing power consumed in the address periods.

In this case, when the video data is used up to the Kth subfield, the data corresponding to the first to (KM) th subfields become invalid data. There is no change. Therefore, according to the first exemplary embodiment of the present invention, even if the number of subfields is increased to reduce the gray scale expression power or pseudo contour, only some of the subfields are masked and used, so that an increase in power consumption due to an increase in the address period can be prevented.

As described above, in the first embodiment of the present invention, when a high weight subfield is used, a low weight subfield is ignored, that is, '0' is assigned to the subfield. In this case, when the first subfield data of the discharge cells located in the first row and the first column is '1' as valid data, and the first subfield data of the discharge cells located in the second row and the first column is invalid data processing and is '0'. Suppose In this case, it is necessary to switch so that an address voltage is applied to one row and one column in the address period of the first subfield, and then a switch is applied such that a beer dress voltage is applied to the second row and one column. This can cause switching to occur due to invalid data, resulting in power loss due to switching. Hereinafter, an embodiment of reducing power loss that may occur due to invalid data will be described with reference to FIGS. 4 and 5.

4 is a flowchart illustrating a method of processing invalid data according to a second embodiment of the present invention, and FIG. 5 is a diagram illustrating data determined according to the method of FIG. 4. In FIG. 4 and FIG. 5, it is assumed that the scanning direction is sequentially made in the column direction. 4 and 5, data of the first subfield is invalid in the image data corresponding to the discharge cells in the i row j columns (the discharge cells formed by the i th Y electrode Yi and the j th address electrode Aj). In the case of data, a method of processing the data will be described. In the terms used below, "before" and "just after" refer to "just before" and "just after", respectively, "before" refers to the time forward including "before" and "after" immediately after Including back in time.

First, referring to FIG. 4, the subfield data generation unit 250 determines whether the data of the first subfield of the discharge cell of the (i + 1) row j column scanned immediately after the i row j column discharge cell is valid data. (S410).

Next, if the data of the first subfield of the discharge cell in row j of (i + 1) is valid data, the subfield data generation unit 250 is scanned immediately before row i of column j in row (i-1) j The data of the first subfield of the discharge cells of the column and the data of the first subfield of the discharge cells of the column j of (i + 1) are compared (S420). If the data of the first subfield of the discharge cell of row (i-1) row j and the discharge cell of row (i + 1) row j is the same, the subfield data generator 250 generates the first row of the discharge row of the row i column j. The subfield data is set to the same data as the discharge cells immediately before and after. That is, as shown in FIG. 5, when the data of the first subfield of the discharge cell in row j column (i-1) and the discharge cell in row j column (i + 1) is both '0', the row i column j cell The invalid data of the first subfield is set to valid data of '0' (S431), and the data of the first subfield of the discharge cell in row j column (i-1) and the j cell in row j column (i + 1) If all are '1', invalid data of the first subfield of the i-row j-column discharge cells is set to valid data of '1' (S432). In this case, since the discharge cells scanned immediately before and immediately after the address data (subfield data) are the same, switching does not occur, and thus power loss due to switching can be eliminated.

As shown in FIG. 5, if the data of the first subfield of the discharge cell in row j column (i-1) and the column j column in row (i + 1) is different from each other, the subfield data generator 250 performs row i. The original data of the first subfield of the j thermal discharge cell is expressed as valid data (S433). In this case, since switching between two adjacent valid data necessarily occurs, no additional switching occurs even if the invalid data is represented as original data. That is, the original data can be represented as it is without additional switching loss.

Next, if the first subfield data of the discharge cell in row j of (i + 1) is not valid data, the subfield data generator 250 scans the discharge cell after the discharge cell in row j of (i + 1) row It is sequentially determined whether the first subfield data is valid data (S440 and S410). That is, the subfield data generation unit 250 determines whether the first subfield data of the discharge cells in row j column of (i + 2) is valid data. If the data of the discharge cells in row (i + 2) j column is not valid data, it is determined whether the first subfield data of the discharge cells of row (i + 3) row j column to be scanned next is valid data, The branch is repeated until the branch is identified. If the first subfield data of the discharge cell in row j column (i + k) is valid data through the processes (S440 and S410), the subfield data generation unit 250 determines the discharge cell in row j column of (i-1) row. The first subfield data is compared with the first subfield data of the discharge cells of the (i + k) row j columns (S420). According to the comparison result, the data of the first subfield of the discharge cells of row i, column j, are set through the methods S431, S432, and S433 described above.

In FIG. 4, a method of processing invalid data of the first subfield has been described. However, even when the data of the first and second subfields are both invalid data, the invalid data may be processed by the method described with reference to FIG. 4. .

As described above with reference to FIG. 4 and FIG. 5, after mapping the image data into the subfield data, the invalid data is sequentially set in the scanning direction and compared with the data of the discharge cells scanned immediately before and after and set as valid data. Can be. In summary, when the K-th subfield is used when mapping image data corresponding to a discharge cell into subfield data, the 1st to (K-M) th subfield data is processed as invalid data. In this case, each invalid data in the first to (KM) th subfield data is determined by the corresponding subfield data of the discharge cell having the first valid data among the discharge cells scanned immediately before the corresponding discharge cell and the discharge cells scanned thereafter. do.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

As described above, according to the present invention, the gray level is expressed using only the j subfields smaller than i among the i subfields previously allocated. Therefore, even if the number of subfields is increased, the address period is not added. Thus, the gray scale expression power can be improved by increasing the number of subfields without increasing the power consumption generated in the address period. In addition, it is possible to set the direction in which the power consumption decreases as compared with the data of the discharge cells scanned immediately before and after without ignoring the invalid data.

Claims (11)

In a plasma display panel in which a plurality of discharge cells are formed in a matrix form, one field is divided into N (N is a natural number) subfields having respective luminance weights, and subfields to which image data is mapped among the N subfields. A driving method of a plasma display panel expressing a gray scale by a sum of weights of A first step of mapping input image data into the N subfields; A second step of setting valid data corresponding to M subfields in which the image data is mapped to the N subfields, where M is a natural number smaller than N; and If invalid data exists after setting the valid data with respect to the image data of the first discharge cell, the second cell is located on the same line as the first discharge cell and is scanned beforehand in time with respect to the first discharge cell. And setting the invalid data according to data of a discharge cell and a third discharge cell which is subsequently scanned in time with respect to the discharge cell and the first discharge cell. The method of claim 1, When arranging the N subfields in order of luminance weight, when the subfield having the highest weight among the subfields to which the image data is mapped in the first step is a K (K is a natural number greater than M) th subfield, A method of driving a plasma display panel in which the image data mapped to the (K-M + 1) th to Kth subfields is set to valid data, and the data of the first to (KM) th subfields are set to invalid data. . The method of claim 2, Invalid data of an i (i is an integer between 1 and (KM)) subfield among the invalid data of the first to (KM) th subfield for the first discharge cell is the ith of the second discharge cell. And the valid data of the subfield and the valid data of the i-th subfield of the third discharge cell. The method of claim 3, The second discharge cell is a discharge cell scanned immediately before the first discharge cell, And wherein the third discharge cell is the first discharge cell in which data of the i-th subfield is valid data among discharge cells scanned after the first discharge cell. The method according to claim 3 or 4, When data of the i-th subfield for the second discharge cell and the third discharge cell are the same, invalid data of the i-th subfield for the first discharge cell is determined by the second discharge cell and the third discharge. A method of driving a plasma display panel set with data of the i-th subfield for a cell. The method according to claim 3 or 4, When data of the i-th subfield for the second discharge cell and the third discharge cell are different, invalid data of the i-th subfield for the first discharge cell may correspond to original data of the first discharge cell. A method of driving a plasma display panel to be held. The method of claim 2, When the N subfields are arranged in luminance weight order, when the subfield having the highest weight among the subfields to which the image data is mapped in the first step is an L (L is a natural number less than or equal to M) subfield, A method for driving a plasma display panel which sets valid data as data of a first to Mth subfields and expresses the image data with the valid data. A plasma display panel in which a plurality of discharge cells are arranged in a matrix form; A driver for applying a driving signal to the discharge cell, and A control unit for dividing a field into N subfields having respective luminance weights to map image data for each discharge cell to the subfields, and to control the driving unit to express gray scales with the data mapped to the subfields; Include, The control unit, when the image data for the first discharge cell uses the K-th sub-field after the M-th when the N sub-fields are arranged in the order of the luminance weight, the first control unit for the first discharge cell And (KM) th subfield data are set according to data of discharge cells scanned before and after each time with respect to the first discharge cell. The method of claim 8, Regarding the data of the i (i is an integer between 1 and (K-M)) subfield among the data of the 1st to (K-M) th subfield for the first discharge cell, The second discharge cell is a discharge cell which is scanned immediately before the first discharge cell and located in the same column as the first discharge cell when the scan of the plurality of discharge cells is performed in the row direction, And the third discharge cell is the first discharge cell using only the subfield before the (i + M) th subfield among the discharge cells scanned after the first discharge cell. The method of claim 9, The control unit, when the i th subfield data of the second discharge cell and the third discharge cell are the same, transmits data of the i th subfield of the first discharge cell to the second discharge cell and the third. And the same plasma display device as the i-th subfield data of the discharge cell. The method of claim 9, The control unit maintains the data of the i-th subfield of the first discharge cell as original data when the i-th subfield data of the second discharge cell and the third discharge cell are different. .

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