KR20080033612A - Plasma display apparatus - Google Patents

Abstract

A plasma display device is provided to reduce an image flicker by preventing a dither mask pattern from being displayed on a screen, when an APL(Average Power Level) is relatively high. A plasma display device includes a PDP(Plasma Display Panel,100) and a driving unit(110). The PDP divides an image frame into first and second sub-field groups. The PDP includes first and second electrodes located parallel to each other, and a third electrode located across the first and second electrodes. When the APL is a first level, the driving unit performs reverse gamma compensation on the image data in the first sub-field group by using a first gamma value and on the image data in the second sub-field group by using a second gamma value. When the APL is a second level, the driving unit performs reverse gamma compensation by using the same gamma value in the first and second sub-field groups.

Description

Plasma Display Apparatus {Plasma Display Apparatus}

1 is a view for explaining an example of the configuration of a plasma display device according to an embodiment of the present invention.

2 is a view for explaining an example of the structure of a plasma display panel that can be included in the plasma display device according to an embodiment of the present invention.

3 is a view for explaining an example where at least one of the first electrode or the second electrode is a plurality of layers;

4 is a view for explaining an example in the case where at least one of the first electrode or the second electrode is a single layer;

FIG. 5 is a diagram for describing an image frame for implementing gray levels of an image in a plasma display device according to an embodiment of the present invention. FIG.

6 is a view for explaining an example of the operation of the plasma display device according to an embodiment of the present invention.

7 is a diagram for explaining an average power level.

8A to 8B are diagrams for describing a first embodiment of a method of processing image data of a first subfield group and a second subfield group.

FIG. 9 is a diagram for describing a second embodiment of a method of processing image data of a first subfield group and a second subfield group. FIG.

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

100: plasma display panel 110: driver

The present invention relates to a plasma display device (Plasma Display Apparatus).

The plasma display apparatus may include a plasma display panel having electrodes formed thereon, and a driving unit supplying driving signals to the electrodes of the plasma display panel.

In general, a phosphor layer is formed in a discharge cell (Cell) partitioned by a partition, and a plurality of electrodes are formed in the plasma display panel.

The driver supplies a driving signal to the discharge cell through the electrode.

Then, the discharge is generated by the drive signal supplied in the discharge cell. Here, when discharged by a drive signal in the discharge cell, the discharge gas filled in the discharge cell generates light such as ultraviolet rays, and the light such as ultraviolet light emits phosphors formed in the discharge cell. Generates visible light The visible light displays an image on the screen of the plasma display panel.

According to an embodiment of the present invention, a flicker is performed by adjusting a data processing method of a first subfield group and a second subfield group of an image frame in relation to an average power level (APL) of input image data. And a plasma display device for reducing the occurrence of noise.

According to an embodiment of the present invention, a plasma display device displays an image in an image frame including a first subfield group and a second subfield group including at least one subfield. If the plasma display panel and the average power level (APL) of the input image data are the first level, the first subfield group is used to display the first subfield group using the first gamma value. Reverse Gamma correction of the data, and in the second subfield group, the image data of the second subfield group is reverse gamma corrected using a second gamma value different from the first gamma value, and the average power level is higher than the first level. In the case of the high second level, inverse gamma correction of corresponding image data is performed using the same gamma value in the first subfield group and the second subfield group.

In addition, when the average power level (APL) of the input image data is the first level, the driver may adjust the image data of the first subfield group by using the first gain value in the first subfield group. The gain is adjusted, and in the second subfield group, the gain of the image data of the second subfield group is adjusted by using a second gain value different from the first gain value, and the second level whose average power level is higher than the first level. In this case, the gain of the corresponding video data is adjusted by using the same gain value in the first subfield group and the second subfield group.

In addition, when the average power level (APL) of the input image data is the first level, the driver may halftone correct the image data of the first subfield group in the first manner from the first subfield group. In the second subfield group, the video data of the second subfield group is halftone-corrected by using a second method different from the first method, and when the average power level is a second level higher than the first level, The video data is halftone corrected in the same manner in the subfield group and the second subfield group.

Hereinafter, a plasma display device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view for explaining an example of the configuration of a plasma display device according to an embodiment of the present invention.

1, a plasma display apparatus according to an embodiment of the present invention includes a plasma display panel 100 and a driver 110.

The plasma display panel 100 displays an image in an image frame including a first subfield group 1 including at least one subfield and a second subfield group 2. Is displayed. In addition, the plasma display panel 100 includes a first electrode and a second electrode which are parallel to each other, and a third electrode which crosses the first electrode and the second electrode.

When the average power level (APL) of the input image data is the first level APL 1, the driver 110 uses the first gamma value from the first subfield group to display the first sub-field. Reverse gamma correction of the image data of the field group, and reverse gamma correction of the image data of the second subfield group using a second gamma value different from the first gamma value in the second subfield group When the average power level is a second level APL2 higher than the first level, inverse gamma correction is performed using the same gamma value in the first subfield group and the second subfield group.

Here, in FIG. 1, only the case in which the driving unit 110 is formed in one board form is illustrated, but in the present invention, the driving unit 110 is divided into a plurality of board forms according to electrodes formed on the plasma display panel 100. It is also possible to lose.

For example, the driver 110 may include a first driver (not shown) for driving the first electrode of the plasma display panel 100, a second driver for driving the second electrode, and a third for driving the third electrode. It can be divided into a driving unit (not shown).

The driving unit 110 of the plasma display device of the present invention will be more clearly described later.

Next, FIG. 2 is a view for explaining an example of a structure of a plasma display panel that may be included in a plasma display device according to an embodiment of the present invention.

Referring to FIG. 2, a plasma display panel that may be included in a plasma display apparatus according to an exemplary embodiment of the present invention has a front substrate 201 in which first electrodes 202 and Y and second electrodes 203 and Z are parallel to each other. ) And the rear substrate 211 on which the third electrodes 213 and X intersecting the first electrodes 202 and Y and the second electrodes 203 and Z are formed.

An electrode such as first electrodes 202 and Y and second electrodes 203 and Z may be formed on the front substrate 201. The first electrodes 202 and Y and the second electrodes 203 and Z may generate a discharge in a discharge space, that is, a discharge cell, and maintain the discharge of the discharge cell.

The dielectric layer covers the first electrode 202 and the second electrode 203 and Z on the front substrate 201 where the first electrode 202 and the second electrode 203 and Z are formed. For example, upper dielectric layer 204 may be formed.

This upper dielectric layer 204 limits the discharge current of the first electrode 202, Y and the second electrode 203, Z and between the first electrode 202, Y and the second electrode 203, Z. Can be insulated.

A protective layer 205 may be formed on the upper dielectric layer 204 to facilitate a discharge condition. The protective layer 205 may be formed through a method of depositing a material such as magnesium oxide (MgO) on the upper dielectric layer 204.

Meanwhile, electrodes, for example, third electrodes 213 and X are formed on the rear substrate 211, and third electrodes 213 and X are formed on the rear substrate 211 on which the third electrodes 213 and X are formed. A dielectric layer, such as lower dielectric layer 215, may be formed to cover the gap.

The lower dielectric layer 215 may insulate the third electrodes 213 and X.

On top of the lower dielectric layer 215, a partition 212, such as a stripe type, a well type, a delta type, a honeycomb type, for partitioning a discharge cell, that is, a discharge cell, is formed. Can be formed. Accordingly, discharge cells such as red (R), green (G), and blue (B) may be formed between the front substrate 201 and the rear substrate 211.

In addition to the red (R), green (G), and blue (B) discharge cells, it is also possible to further form a white (W) or yellow (Yellow: Y) discharge cell.

On the other hand, the pitch of the red (R), green (G) and blue (B) discharge cells in the plasma display panel that can be included in the plasma display device according to an embodiment of the present invention may be substantially the same. The pitches of the red (R), green (G) and blue (B) discharge cells may be varied to match the color temperature in the red (R), green (G) and blue (B) discharge cells.

In this case, the pitch may be different for each of the red (R), green (G), and blue (B) discharge cells, but the pitch of one or more discharge cells among the red (R), green (G), and blue (B) discharge cells. May be different from the pitch of other discharge cells. For example, the pitch of the red (R) discharge cells is the smallest, and the pitch of the green (G) and blue (B) discharge cells may be larger than the pitch of the red (R) discharge cells.

Here, the pitch of the green (G) discharge cells may be substantially the same as or different from the pitch of the blue (B) discharge cells.

In addition, the plasma display panel that may be included in the plasma display apparatus according to an exemplary embodiment of the present invention may have not only the structure of the partition 212 illustrated in FIG. 2 but also the structure of the partition having various shapes. For example, the partition 212 includes a first partition 212b and a second partition 212a, where the height of the first partition 212b and the height of the second partition 212a are different from each other. At least one of the first barrier rib 212b and the second barrier rib 212a, and a channel type barrier rib structure having a channel usable as an exhaust passage, at least one of the first barrier rib 212b and the second barrier rib 212a. Grooved partition wall structure having a groove formed in the groove will be possible.

Here, in the case of the differential partition structure, the height of the first partition 212b of the first partition 212b or the second partition 212a may be lower than the height of the second partition 212a. In addition, in the case of the channel barrier rib structure or the groove barrier rib structure, a channel or a groove may be formed in the first barrier rib 212b.

On the other hand, in the plasma display panel that can be included in the plasma display device according to an embodiment of the present invention, although the red (R), green (G) and blue (B) discharge cells are shown and described as being arranged on the same line, It may be possible to arrange them in other shapes. For example, a delta type arrangement in which red (R), green (G) and blue (B) discharge cells are arranged in a triangular shape may be possible. In addition, the shape of the discharge cell may also be a variety of polygonal shapes, such as pentagonal, hexagonal, as well as rectangular.

In addition, in FIG. 2, only the case where the partition wall 212 is formed on the rear substrate 211 is illustrated, but the partition wall 212 may be formed on at least one of the front substrate 201 and the rear substrate 211.

Here, a predetermined discharge gas may be filled in the discharge cell partitioned by the partition wall 212.

In addition, a phosphor layer 214 that emits visible light for image display may be formed in the discharge cells partitioned by the partition wall 212. For example, red (R), green (G), and blue (B) phosphor layers may be formed.

In addition to the red (R), green (G), and blue (B) phosphors, it is also possible to further form a white (W) and / or yellow (Y) phosphor layer.

In addition, the phosphor layers 214 of the red (R), green (G), and blue (B) discharge cells may have substantially the same thickness or may differ from one or more. For example, if the thickness of the phosphor layer 214 in at least one of the red (R), green (G), and blue (B) discharge cells is different from the other discharge cells, green (G) or blue (B) The thickness of the phosphor layer 214 in the discharge cell may be thicker than the thickness of the phosphor layer 214 in the red (R) discharge cell. Here, the thickness of the phosphor layer 214 in the green (G) discharge cell may be substantially the same as or different from the thickness of the phosphor layer 214 in the blue (B) discharge cell.

In the above description, only one example of the plasma display panel which may be included in the plasma display apparatus according to the exemplary embodiment of the present invention is illustrated and described. However, one embodiment of the present invention is not limited to the plasma display panel having the above-described structure. To reveal. For example, the description hereinabove illustrates only the case where the top dielectric layer at number 204 and the bottom dielectric layer at number 215 are each one layer, but one or more of these top dielectric layers and bottom dielectric layers are a plurality of layers. It can also be layered.

In addition, a black layer (not shown) may be further formed on the partition 212 to prevent reflection of the external light due to the partition 212.

In addition, a black layer (not shown) may be further formed at a specific position on the front substrate 201 corresponding to the partition 212.

In addition, the width or thickness of the third electrode 213 formed on the rear substrate 211 may be substantially constant, but the width or thickness inside the discharge cell may be different from the width or thickness outside the discharge cell. will be. For example, the width or thickness inside the discharge cell may be wider or thicker than that outside the discharge cell.

Next, FIG. 3 is a figure for explaining an example in the case where at least one of a 1st electrode or a 2nd electrode is a some layer.

Referring to FIG. 3, at least one of the first electrode 202 or the second electrode 203 may be formed of a plurality of layers, for example, two layers.

For example, in consideration of light transmittance and electrical conductivity, at least one of the first electrode 202 or the second electrode 203 is made of silver (silver) to emit light generated in the discharge cell to the outside and to secure driving efficiency. Bus electrodes 202b and 203b including a substantially opaque material such as Ag) and transparent electrodes 202a and 203a including a transparent material such as transparent indium tin oxide (ITO). .

As such, when the first electrode 202 and the second electrode 203 include the transparent electrodes 202a and 203a, visible light generated in the discharge cell can be effectively emitted when emitted to the outside of the plasma display panel. .

In addition, when the first electrode 202 and the second electrode 203 include the bus electrodes 202b and 203b, the first electrode 202 and the second electrode 203 include only the transparent electrodes 202a and 203a. In this case, the driving efficiency can be reduced because the electrical conductivity of the transparent electrodes 202a and 203a is relatively low, and it is possible to compensate for the low electrical conductivity of the transparent electrodes 202a and 203a which can cause such a reduction in the driving efficiency. Can be.

As described above, in the case where the first electrode 202 and the second electrode 203 include the bus electrodes 202b and 203b, the transparent electrodes 202a and 203b may be used to prevent reflection of external light by the bus electrodes 202b and 203b. Black layers 320 and 321 may be further provided between the 203a and the bus electrodes 202b and 203b.

Next, FIG. 4 is a figure for explaining an example in the case where at least one of a 1st electrode or a 2nd electrode is a single layer.

Referring to FIG. 4, the first electrodes 202 and Y and the second electrodes 203 and Z are one layer. For example, the first electrodes 202 and Y and the second electrodes 203 and Z may be electrodes (ITO-Less) in which the transparent electrode of numeral 202a or 203a is omitted in FIG. 3.

At least one of the first electrode 202 and Y or the second electrode 203 and Z may include a substantially opaque electrically conductive metal material. For example, it may include a material having excellent electrical conductivity such as silver (Ag), copper (Cu), aluminum (Al), and the like, and a material having a lower cost than a transparent material such as indium tin oxide (ITO). .

In addition, at least one of the first electrode 202, Y or the second electrode 203, Z may be darker in color than the upper dielectric layer 204 of FIG. 2.

As such, when at least one of the first electrode 202 and the second electrode 203 and Z is a single layer, the manufacturing process is simpler than in the case of FIG. 3. For example, in the case of FIG. 3, the bus electrodes 202b and 203b are formed after the transparent electrodes 202a and 203a are formed in the process of forming the first electrodes 202 and Y and the second electrodes 203 and Z. 4 again, the first electrode 202 and Y and the second electrode 203 and Z can be formed in one process because the single layer structure of FIG.

In addition, as shown in FIG. 4, when the first electrodes 202 and Y and the second electrodes 203 and Z are formed in a single layer, the manufacturing process is simplified and relatively expensive indium-tin-oxide (ITO) or the like. Since it is not necessary to use a transparent material of the manufacturing cost can be reduced.

Meanwhile, discoloration of the front substrate 201 is prevented between the first electrodes 202 and Y and the second electrodes 203 and Z and the front substrate 201, and the first electrode 202 or Y or the second electrode ( Black layers 400a and 400b having a darker color than at least one of 203 and Z) may be further provided. That is, when the front substrate 201 and the first electrode 202, Y or the second electrode 203, Z are in direct contact, the first electrode 202, Y or the second electrode 203, Z is directly in contact with each other. Migration phenomenon may occur in which a predetermined area of the front substrate 201 that is in contact with the yellow color is changed. The black layers 400a and 400b may prevent the migration of the front substrate 201 by preventing the migration phenomenon. It can be.

The black layers 400a and 400b may include black materials such as ruthenium (Ru) having a substantially dark color.

As such, when the black layers 400a and 400b are provided between the front substrate 201 and the first electrodes 202 and Y and the second electrodes 203 and Z, the first electrodes 202 and Y may be provided. Even if the second electrodes 203 and Z are made of a material having high reflectance, generation of reflected light can be prevented.

As such, the structure of the plasma display panel which may be included in the plasma display apparatus according to the exemplary embodiment may be variously changed.

Next, FIG. 5 is a diagram for describing an image frame for implementing gradation of an image in a plasma display device according to an embodiment of the present invention.

Referring to FIG. 5, in a plasma display device according to an embodiment of the present invention, an image frame for implementing gray levels of an image may include a first subfield group and a second subfield group including at least one subfield. Include.

The first subfield group and the second subfield group may be divided into a plurality of subfields each having a different number of emission times.

Although not shown, one or more subfields among the plurality of subfields may be grayed out according to a reset period for initializing discharge cells, an address period for selecting discharge cells to be discharged, and the number of discharges. It can be divided into the sustain period to implement.

For example, when an image is to be displayed with 256 gray levels, for example, one image frame is divided into 12 subfields SF1 to SF12 as shown in FIG. 5, and each of the 12 subfields SF1 to SF12, respectively. Can be subdivided into a reset period, an address period and a sustain period.

The gray scale weight of the corresponding subfield may be set by adjusting the number of the sustain signals supplied in the sustain period. That is, a predetermined gray scale weight can be given to each subfield using the sustain period. For example, the first subfield group in the first subfield setting the gray scale weight of 2 ^0, and the second by setting the gray scale weight of the subfield to 2 ^1, gray level weight of each subfield 2 ⁿ (only the , gradation weights of each subfield may be determined to increase at a ratio of n = 0, 1, 2, 3, 4, and 5). As described above, the number of sustain signals supplied in the sustain period of each subfield is adjusted according to the gray scale weight in each subfield, thereby implementing gray levels of various images.

A plasma display panel according to an embodiment of the present invention uses a plurality of image frames to implement an image, for example, to display an image of 1 second. For example, 50 image frames are used to display an image of 1 second. In this case, the length T of one image frame may be 1/50 second, that is, 20 ms.

In FIG. 5, only one subframe consists of 12 subfields, each of which includes six first subfields and six second subfields. However, the number of subfields forming one image frame may vary. Can be changed. For example, at least one of the first subfield and the second subfield may include seven subfields from the first subfield to the seventh subfield, or may include eight subfields.

Also, in FIG. 5, subfields are arranged in increasing order of gray scale weights in the first subfield group and the second subfield group. Alternatively, at least one of the first subfield group and the second subfield group is different. In subfields, subfields may be arranged in the order of decreasing gray scale weights, or subfields may be arranged regardless of gray scale weights.

In FIG. 5, only the case where the number of subfields included in the first subfield group and the second subfield group are the same is illustrated and described. However, the number of subfields included in the first subfield group and the second subfield group are different from each other. The number of subfields included in the subfield group may be different.

Meanwhile, as described above, when one image frame includes a first subfield group and a second subfield group each including at least one subfield, one image frame is visually displayed as two image frames. The effect can be obtained. Accordingly, the method of realizing an image with 50 image frames per second, that is, the effect of realizing an image with 100 image frames per second in a 50 ms method is obtained. Therefore, when the image is implemented, the generation of flicker can be reduced.

6 is a view for explaining an example of the operation of the plasma display device according to an embodiment of the present invention.

Referring to FIG. 6, an example of an operation of a plasma display apparatus according to an exemplary embodiment of the present invention is shown in any one of a plurality of subfields included in an image frame as shown in FIG. 5.

First, the first ramp-down signal may be supplied to the first electrode Y in the pre-reset period before the reset period.

In addition, while the first falling ramp signal is supplied to the first electrode Y, a pre-sustain signal in a polarity opposite to the first falling ramp signal may be supplied to the second electrode Z.

Here, the first falling ramp signal supplied to the first electrode Y may gradually fall to the tenth voltage V10.

In addition, the pre-sustain signal can keep the pre-sustain voltage Vpz substantially constant. Here, the pre-sustain voltage Vpz may be a voltage of the sustain signal SUS supplied in a subsequent sustain period, that is, a voltage approximately equal to the sustain voltage Vs.

As such, when the first falling ramp signal is supplied to the first electrode Y and the presuspension signal is supplied to the second electrode Z in the pre-reset period, a wall of a predetermined polarity is formed on the first electrode Y. Wall charges are accumulated, and wall charges of opposite polarity to the first electrode Y are accumulated on the second electrode Z. For example, positive wall charges may be accumulated on the first electrode Y, and negative wall charges may be accumulated on the second electrode Z.

This makes it possible to generate a set-up discharge of sufficient intensity in the subsequent reset period, which in turn makes it possible to perform the initialization sufficiently stably.

In addition, even if the voltage of the rising ramp signal Ramp-Up supplied to the first electrode Y becomes smaller in the reset period, it is possible to generate the setup discharge of sufficient intensity.

From the viewpoint of securing the driving time, a pre-reset period is included before the reset period in the subfields arranged first in time among the subfields of the image frame, or before the reset period in two or three subfields of the subfields of the image frame. It is also possible to include a pre-reset period.

Alternatively, this pre-reset period may be omitted in all subfields.

After the pre-reset period, in a set-up period of a reset period for initialization, a ramp-up signal in a direction opposite to that of the first falling ramp signal may be supplied to the first electrode Y.

Here, the rising ramp signal may include a first rising ramp signal gradually increasing with a first slope from the twentieth voltage V20 to the thirtieth voltage V30 and the second rising ramp signal from the thirtieth voltage V30 to the forty-th voltage V40. It may include a second rising ramp signal rising to the slope.

In this setup period, a weak dark discharge, that is, setup discharge, occurs in the discharge cell by the rising ramp signal. By this setup discharge, some wall charges can be accumulated in the discharge cells.

Here, it is preferable that the second slope of the second rising ramp signal is gentler than the first slope. As such, when the second slope is made gentler than the first slope, the voltage is increased relatively quickly until the setup discharge occurs, and the voltage is increased relatively slowly while the setup discharge occurs. The amount of light generated by the setup discharge can be reduced.

Accordingly, the contrast characteristic can be improved.

In a set-down period after the set-up period, a second ramp-down signal in a direction opposite to that of the ramp ramp signal may be supplied to the first electrode Y after the ramp ramp signal.

Here, the second falling ramp signal may gradually fall from the 20th voltage V20 to the 50th voltage V50.

As a result, weak erase discharge, that is, set-down discharge, occurs in the discharge cell. By this set-down discharge, wall charges such that address discharge can be stably generated in the discharge cells remain uniformly.

Meanwhile, in the address period after the reset period, a scan bias signal that substantially maintains a voltage higher than the 50 th voltage V50 of the second falling ramp signal may be supplied to the first electrode Y. FIG.

In addition, the scan signal Scan, which decreases from the scan bias signal by the scan voltage ΔVy, may be supplied to all of the first electrodes Y1 to Yn.

For example, the first scan signal Scan 1 is supplied to the first first electrode Y1 of the plurality of first electrodes Y, and then the second scan signal (2) is applied to the second first electrode Y2. Scan 2) is supplied, and the n-th scan signal Scan n is supplied to the n-th first electrode Yn.

On the other hand, the width of the scan signal in units of subfields may vary. That is, the width of the scan signal in at least one subfield may be different from the width of the scan signal in another subfield. For example, the width of the scan signal Scan in the subfield located later in time may be smaller than the width of the scan signal Scan in the subfield located earlier. In addition, the scan signal scan width decreases according to the arrangement order of the subfields gradually, such as 2.6 ms (microseconds), 2.3 ms (microseconds), 2.1 ms (microseconds), 1.9 ms (microseconds), and the like. Or 2.6 ㎲ (microseconds), 2.3 ㎲ (microseconds), 2.3 ㎲ (microseconds), 2.1 ㎲ (microseconds) ... 1.9 ㎲ (microseconds), 1.9 ㎲ (microseconds) It could be done.

As such, when the scan signal Scan is supplied to the first electrode Y, a data signal rising by the magnitude ΔVd of the data voltage may be supplied to the third electrode X to correspond to the scan signal.

As the scan signal Scan and the data signal Data are supplied, the voltage difference between the voltage of the scan signal and the data voltage Vd of the data signal and the wall voltage generated by the wall charges generated in the reset period are In addition, address discharge may occur in a discharge cell to which the voltage Vd of the data signal is supplied.

Here, a sustain bias signal may be supplied to the second electrode Z to prevent address discharge from becoming unstable due to interference of the second electrode Z in the address period.

Here, the sustain bias signal may maintain a substantially constant sustain bias voltage Vz smaller than the voltage of the sustain signal supplied in the sustain period and greater than the voltage of the ground level GND.

Thereafter, in the sustain period for displaying an image, the sustain signal SUS may be supplied to at least one of the first electrode Y and the second electrode Z. FIG. For example, the sustain signal SUS may be alternately supplied to the first electrode Y and the second electrode Z. FIG.

When the sustain signal SUS is supplied, the discharge cell selected by the address discharge is added with the wall voltage in the discharge cell and the sustain voltage Vs of the sustain signal SUS, and the first electrode when the sustain signal SUS is supplied. A sustain discharge, that is, a display discharge, may be generated between (Y) and the second electrode Z.

Next, FIG. 7 is a diagram for explaining an average power level.

Referring to FIG. 7, the average power level is a method of adjusting the number of sustain signals in relation to the size of a portion where an image is displayed on the plasma display panel. That is, the average power level is determined according to the number of discharge cells that are turned on among the discharge cells of the plasma display panel.

Preferably, as the value of the average power level APL increases, the number of sustain signals per unit gray scale decreases, and as the value of the average power level APL decreases, the number of sustain signals per unit gray scale increases.

For example, when an image is displayed on a portion of a relatively small area on the screen of the plasma display panel 600 as shown in (a), that is, a discharge cell that is turned on among discharge cells formed in the plasma display panel 600. When the number of cells is relatively small (in this case, the APL level is relatively low), since the number of discharge cells contributing to the image display is relatively small, the sustain per unit gradation supplied to each discharge cell contributing to the image display is relatively small. Make the number of signals relatively large. Accordingly, the overall brightness of the image can be increased.

On the contrary, when an image is displayed on a portion of a relatively large area on the screen of the plasma display panel 600 as shown in (b), that is, the number of discharge cells turned on among the discharge cells formed in the plasma display panel 600 is relatively high. In many cases (in this case, the APL level is relatively high), since the number of discharge cells contributing to the image display is relatively large, the number of sustain signals per unit gradation supplied to each discharge cell contributing to the image display is determined. Relatively few. Accordingly, a sudden increase in the total power consumption of the plasma display panel 600 is prevented.

As an example, when the average power level is a level, in this case, the number of sustain signals per unit gradation is N.

In addition, when the average power level is a b level higher than the above-described a level, the number of sustain signals per unit gray level may be M less than N described above.

8A to 8B illustrate an example of a method for reverse gamma correction, gain adjustment, and halftone correction of image data input in relation to the average power level and the image frame described above. In connection with the following.

8A to 8B are diagrams for describing a first embodiment of a method of processing image data of a first subfield group and a second subfield group.

First, referring to FIG. 8A, when the average power level (APL) of the input image data is a relatively low first level APL 1, the first inverse gamma of the image data corresponding to the first subfield group is shown. The corrector 700 may perform inverse gamma correction using the first gamma value.

In contrast, the gamma correction is nonlinear to human visual perception, whereas the plasma display device generates an image as an on or off of a discharge cell, and thus occurs due to the linear luminance of the image. This is done to reduce noise.

In addition, the first gain adjusting unit 710 may adjust the gain of the image data inversely gamma corrected using the first gamma value using the first gain value. The first gain control unit 710 may vary at least one gain among red (R) image data, green (G) image data, and blue (B) image data. For example, the gain of the blue (B) image data and the green (G) image data may be greater than the gain of the red (R) image data.

The first halftone correcting unit 720 may half-tone correct the image data gain-adjusted by the first gain adjusting unit 710 using the first method. For example, the image data may be halftone corrected by using error diffusion or dithering. Such halftone correction improves the gray scale expressive power of an image by generating intermediate gray scales between real gray scales.

On the other hand, inverse gamma correction may be performed by the second inverse gamma correction unit 701 by using the second gamma value in image data corresponding to the second subfield group. Here, the second gamma value is different from the first gamma value used by the first inverse gamma correction unit 700.

In addition, the second gain adjusting unit 711 may adjust the gain of the image data inversely gamma corrected using the second gamma value using the second gain value. Here, the second gain value is different from the first gain value used by the first gain control unit 710.

In addition, the second halftone correcting unit 721 may half-tone correct the image data obtained by the second gain adjusting unit 711 using the second method. Here, the second method is different from the first method used by the first halftone corrector 720. For example, in the case of the error diffusion method, the first and second methods have different error diffusion coefficients. Alternatively, in the dithering method, the first and second methods have different dithering noise values or different dither mask patterns.

That is, when the average power level of the input image data is a relatively low first level APL 1, the reverse gamma correction is performed on the image data of the first subfield group using the first gamma value. Also, gain adjustment is performed using the first gain value, and halftone correction is also performed in the first manner, while image data of the second subfield group is inverse gamma corrected using the second gamma value, and also the second gain value is used. The gain is adjusted using, and halftone correction is also performed in the second manner.

As described above, the image data corresponding to the halftone-corrected first subfield group and the second subfield group are mapped such that the subfield mapping unit 730 corresponds to the first subfield group and the second subfield group. )can do.

As such, the subfield-mapped image data may be supplied to the third electrode in the form of a data signal in the address period as shown in FIG. 6.

As such, when the average power level is relatively low, inverse gamma correction, gain adjustment, and halftone correction are performed on the image data of the first subfield group and the second subfield group of the image frame in different ways. It is easy to match the light center of the first subfield group with the light center of the second subfield group, thereby effectively reducing flicker.

Next, referring to FIG. 8B, when the average power level is the second level APL 2 that is relatively higher than the first level APL 1, the image data corresponding to the first subfield group and the second subfield group correspond. Inverse gamma correction may be performed on the same image data using the same gamma value in the same inverse gamma correction unit 740.

The gain of the reverse gamma corrected image data may be adjusted by the same gain controller 750 using the same gain value.

The half-tone correction of the gain-adjusted image data may be performed by the same halftone correcting unit 760 using the same method.

As described above, when the average power level is relatively high, inverse gamma correction, gain adjustment, and halftone correction of image data corresponding to the first subfield group and the second subfield group are performed in the same manner.

If the average power level is relatively high, the number of sustain signals per gray level is relatively small. As a result, the gray level of the image to be implemented may be lower than when the average power level is relatively low. As such, when the gray level is relatively low, the flicker is relatively low even if the optical center of the first subfield group and the second subfield group does not match. On the other hand, when the patterns of the dither masks used in the first subfield group and the second subfield group are different from each other, the likelihood of the dither mask being visually displayed on the screen is relatively high.

Therefore, when the average power level is relatively high, inverse gamma correction, gain adjustment, and halftone correction are performed in the same manner in the first subfield group and the second subfield group.

On the other hand, in the above, only the gain adjustment after the inverse gamma correction, and only the case of halftone correction thereafter has been shown and described, differently, the reverse gamma correction, gain control and half can be performed such as inverse gamma correction after gain adjustment The order of tone correction can be changed in various ways.

Next, FIG. 9 is a diagram for describing a second exemplary embodiment of a method of processing image data of a first subfield group and a second subfield group. In FIG. 9, the description of the contents already described in detail will be omitted.

Referring to FIG. 9, when the average power level of the input image data is a relatively low first level APL 1, the first inverse gamma correction unit 800 may convert the first gamma value into the image data corresponding to the first subfield group. Inverse gamma correction can be performed.

In addition, the first gain adjusting unit 810 may adjust the gain of the image data inversely gamma corrected using the first gamma value using the first gain value.

The first halftone corrector 830 may half-correct the image data gain-adjusted by the first gain adjuster 810 in a first manner.

Here, the first error corrector of number 820 does not operate.

On the other hand, the image data corresponding to the second subfield group may be reverse gamma corrected by the second inverse gamma correction unit 801 using the second gamma value.

In addition, the gain of the image data inversely gamma corrected using the second gamma value may be adjusted by the second gain adjusting unit 811 using the second gain value.

The second halftone corrector 831 may half-correct the image data gain-adjusted by the second gain adjuster 811 in a second manner.

Here, the second error correction unit of No. 821 does not operate.

The method described above is the same as the method of FIG. 8A.

On the other hand, when the average power level of the input image data is the second level APL 2 that is higher than the first level APL 1, the first error correcting unit 820 and the second error correcting unit 820 operate. Image data input to the first halftone correction unit 830 and image data input to the second halftone correction unit 831 are substantially the same.

For example, the first error correction unit 820 may include the first gain adjuster such that the image data output by the first gain adjuster 810 is substantially the same as the image data output by the second gain adjuster 811. The image data output by 810 may be corrected. Alternatively, the second error correcting unit 821 may include the second gain adjusting unit 811 such that the image data output by the second gain adjusting unit 811 is substantially the same as the image data output by the first gain adjusting unit 810. The image data output can be corrected.

Alternatively, the first error correcting unit 820 adds a first correction value B to the image data A output by the first gain adjusting unit 810, and the second error correcting unit 821 makes a second correction. By adding the second correction value D to the image data C output by the gain adjuster 811, the image data A and the first correction value B output by the first gain adjuster 810. It is also possible to make the computed value A + B of? And the computed value C + D of the image data C and the second correction value D output by the second gain adjuster 811 substantially equal? .

That is, the same inverse gamma correction is performed on the image data of the first subfield group and the image data of the second subfield group without using the same image processing path as shown in FIG. 8B. In this case, the image processing effect can be obtained by adjusting the gain and the halftone correction.

As such, the technical configuration of the present invention described above can be understood by those skilled in the art that the present invention can be implemented in other specific forms without changing the technical spirit or essential features of the present invention.

Therefore, the exemplary embodiments described above are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the appended claims rather than the foregoing detailed description, and the meaning and scope of the claims are as follows. And all changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

As described above in detail, in the plasma display device according to an embodiment of the present invention, a first subfield group and a second subfield of an image frame are related to an average power level (APL) of input image data. By adjusting the group of image data processing methods, the dither mask pattern can reduce noise on the screen when the average power level is relatively high, and reduce flicker when the average power level is relatively low. .

Claims (3)

A plasma display panel displaying an image in an image frame including a first subfield group and a second subfield group including at least one subfield; When the average power level (APL) of the input image data is the first level, the image data of the first subfield group is inversely gamma using a first gamma value in the first subfield group. (Reverse Gamma) correcting, inversely gamma correcting image data of the second subfield group using a second gamma value different from the first gamma value in the second subfield group, and the average power level is higher than the first level. And at a second level, inversely gamma corrects the corresponding image data using the same gamma value in the first subfield group and the second subfield group. The method of claim 1, When the average power level (APL) of the input image data is the first level, the driving unit uses the first gain value in the first subfield group to generate the image data of the first subfield group. Adjust the gain of the second subfield group, and adjust the gain of the image data of the second subfield group using a second gain value different from the first gain value, wherein the average power level is greater than the first level. The plasma display apparatus of claim 1, wherein the gain of the corresponding image data is adjusted by using the same gain value in the first subfield group and the second subfield group in the case of the high second level. The method of claim 1, When the average power level (APL) of the input image data is a first level, the driving unit halftones the image data of the first subfield group in a first manner from the first subfield group. The second subfield group is half-tone corrected for image data of the second subfield group using a second method different from the first method, and the average power level is a second level higher than the first level. In this case, the plasma display apparatus halftone corrects the image data in the same manner in the first subfield group and the second subfield group.

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