KR100740105B1 - Plasma display and driving method thereof - Google Patents

Abstract

In a plasma display device, a plurality of subfields are divided into a plurality of subfield groups, and a plurality of row electrodes for performing a display operation are divided into a plurality of row groups. Each subfield of the first subfield group selects a non-light emitting cell among the light emitting cells of each row group during a first address period for each row group of the plurality of row groups. The discharge cells in the light emitting cell states of the plurality of row groups are sustained and discharged during the first sustaining period located between two adjacent first address periods. At this time, the length of the first address period is set within 20 ms. Then, the width of the scan pulse applied to the plurality of row electrodes in the first address period can be set to 0.3 ms or less, thereby enabling high-speed scanning.

PDP, electrode, discharge, selective write, selective erase, reset, gradation, fast scan

Description

Plasma display device and driving method thereof {PLASMA DISPLAY AND DRIVING METHOD THEREOF}

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

2 is a diagram schematically illustrating a method of driving a plasma display device according to a first embodiment of the present invention.

3 is a view illustrating a driving waveform of a specific plasma display device of the driving method shown in FIG. 2.

4A to 4C are diagrams showing the delay times of the erase discharges according to the time until the scan pulse is applied to the Y electrode after the last sustain discharge in the R, G and B discharge cells, respectively.

5 and 6 are schematic views illustrating a method of driving a plasma display device according to second and third embodiments of the present invention, respectively.

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

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, a plurality of discharge cells are arranged in a matrix form.

In the plasma display device, one field (1TV field) is divided into a plurality of subfields having respective weights and driven, and the gray level is displayed by a combination of the weights of the subfields in which the display operation occurs among the plurality of subfields. Each subfield includes a reset period, an address period, and a sustain period. The reset period is a period for initializing the state of the discharge cells in order to stably perform the next address discharge, and the address period is a period for selecting discharge cells to emit light and discharge cells not to emit light among the plurality of discharge cells. The sustain period is a period in which sustain discharge is performed on the discharge cells selected in the address period in order to actually display an image.

At this time, there is a method of performing the sustain discharge operation on all the discharge cells after completing the addressing operation for all the discharge cells in each subfield, that is, a method of temporally separating the address period and the sustain period. This is generally referred to as an address display period separation (ADS) method. The ADS method can be easily implemented, but since addressing operations are sequentially performed on all discharge cells, address discharge may not occur well due to a lack of priming particles in the discharge cells in the discharge cells that are addressed later in time. Therefore, the width of the scan pulses sequentially applied to the scan electrodes is inevitably increased for stable address discharge, thereby increasing the length of the address period. As a result, the length of the subfield is increased, which limits the number of subfields that can be used in one field.

Unlike the ADS method, an address pulse of each line is inserted between successive sustain discharge pulses to perform an addressing operation on another line while sustain discharge is performed on one line. That is, the method does not separate the address period and the sustain period, which is generally referred to as an address while display (AWD) method. In this AWD method, since the address pulse and the sustain discharge pulse proceed in succession, a reset pulse for initialization must be entered between these successive pulses. Therefore, a reset pulse that requires a long time cannot be used. That is, since the reset discharge must be performed with a strong discharge, the black screen looks bright and the contrast ratio worsens.

In addition, both the ADS method and the AWD method use subfields having different weights for gray scale representation. For example, in the case of using a weighted subfield in the form of a power of 2, a pseudo contour is generated when one discharge cell expresses 127 gray levels and 128 gray levels, respectively, in two consecutive frames.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a plasma display device and a method of driving the same, capable of high-speed addressing and improving contrast ratio. Another object of the present invention is to provide a plasma display device and a driving method thereof capable of reducing pseudo contours and increasing the number of gray scales that can be expressed by a combination of subfields.

According to one aspect of the present invention, in a plasma display device including a plurality of row electrodes and a plurality of column electrodes for performing a display operation, and a plurality of discharge cells defined by the row electrodes and the column electrodes, respectively, A driving method is provided by dividing the into a plurality of subfields. The driving method divides the plurality of row electrodes into a plurality of row groups, divides the plurality of subfields into a plurality of subfield groups, and in each subfield of the first subfield group, each of the plurality of row groups. Selecting a non-light emitting cell among light emitting cells of each row group during a first address period for a row group, and in each subfield of the first subfield group, located between two adjacent first address periods Sustain-discharging discharge cells in the light-emitting cell states of the plurality of row groups during a first sustain period, wherein the length of the first address period for each row group of the plurality of row groups is within 20 ms.

According to another feature of the present invention, in a plasma display device including a plurality of row electrodes and a plurality of column electrodes for performing a display operation, and a plurality of discharge cells defined by the row electrodes and the column electrodes, respectively, A driving method is provided by dividing the into a plurality of subfields. The driving method divides the plurality of row electrodes into a plurality of row groups, divides the plurality of subfields into a plurality of subfield groups, and in each subfield of the first subfield group, each row of the plurality of row groups Selecting a non-light emitting cell among the light emitting cells of each row group during a first address period for the group, and in each subfield of the first subfield group, a second cell positioned between two adjacent first address periods; Sustain-discharging the discharge cells in the light-emitting cell state of the plurality of row groups for one sustain period, wherein each row group of the plurality of row groups includes up to 66 row electrodes.

According to still another aspect of the present invention, a plasma display device including a plasma display panel, a controller, and a driver is provided. The plasma display panel includes a plurality of row electrodes including a first electrode and a second electrode for performing a display operation, and a plurality of column electrodes formed in a direction crossing the row electrodes, wherein the plurality of row electrodes and the plurality of row electrodes A plurality of discharge cells are formed by the column electrodes. The control unit divides the plurality of subfields into a plurality of subfield groups, and divides the plurality of row electrodes into a plurality of row groups. The driver may select a non-light emitting cell among light emitting cells of each row group of the plurality of row groups in a first address period for each row group of the plurality of row groups in each subfield of the first subfield group. The discharge cells in the light emitting cell states of the plurality of row groups are sustained and discharged during the first sustaining period located between two adjacent first address periods. In this case, the driving unit sequentially applies a scan pulse having a width of 0.3 μs or less to the plurality of row electrodes of each row group, and applies an address pulse to the column electrode of the light emitting cell to which the scan pulse is applied. Select a non-emitting cell.

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.

In addition, the wall charge in the present invention refers to a charge formed close to each electrode on the wall (eg, the dielectric layer) of the cell. And the wall charge is not actually in contact with the electrode itself, but is described here as “formed”, “accumulated” or “stacked” on the electrode. In addition, the wall voltage refers to the potential difference formed in the wall of the cell by the wall charge.

First, a plasma display device according to an exemplary embodiment of the present invention will be described in detail with reference to FIG. 1.

1 is a diagram illustrating 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 electrode driver 300, a scan electrode driver 400, and a sustain electrode driver 500. It includes.

The plasma display panel 100 includes a plurality of address electrodes (hereinafter referred to as “A electrodes”) A1 to Am extending in the column direction, and a plurality of sustain electrodes extending in pairs to each other in the row direction (hereinafter, “X”). Electrodes ”(X1 to Xn) and scan electrodes (hereinafter referred to as“ Y electrodes ”) (Y1 to Yn). In general, the X electrodes X1 to Xn are formed corresponding to the respective Y electrodes Y1 to Yn, and the X electrode and the Y electrode perform a display operation for displaying an image in the sustain period. The Y electrodes Y1 to Yn and the X electrodes X1 to Xn are arranged to be orthogonal to the A electrodes A1 to Am. At this time, the discharge space at the intersection of the A electrodes A1 to Am and the X and Y electrodes X1 to Xn and Y1 to Yn forms the cell 12. The structure of the plasma display panel 100 is an example, and a panel having another structure to which the driving waveform described below may be applied may also be applied to the present invention.

The controller 200 receives an image signal from the outside and outputs an A electrode driving control signal, an X electrode driving control signal, and a Y electrode driving control signal. In this case, the controller 200 divides and drives one frame into a plurality of subfields having respective luminance weights, and the plurality of subfields are driven into a plurality of groups again. In addition, the plurality of X electrodes and the Y electrodes are divided into a plurality of groups and driven.

The address electrode driver 300 receives the A electrode driving control signal from the controller 200 and applies a driving voltage to the A electrodes A1 to Am.

The scan electrode driver 400 receives the Y electrode driving control signal from the controller 200 and applies a driving voltage to the Y electrodes Y1 to Yn.

The sustain electrode driver 500 receives the X electrode driving control signal from the controller 200 and applies a driving voltage to the X electrodes X1 to Xn.

In the following description, the X electrode and the Y electrode extending in pairs with each other in the row direction are referred to as row electrodes, and the A electrode extending in the column direction is referred to as column electrodes.

Next, a driving method of the plasma display device according to the first embodiment of the present invention will be described in detail with reference to FIG. 2. In the first embodiment of the present invention, the lengths of the sustain periods applied after the address period of each row group are the same, and the sustain periods have the same length in all the subfields.

2 is a diagram schematically illustrating a method of driving a plasma display device according to a first embodiment of the present invention.

As shown in Fig. 2, one field consists of a plurality of subfields SF11-SF1L, and the plurality of row electrodes X1 to Xn and Y1 to Yn are divided into a plurality of row groups. In FIG. 2, it is assumed that the plurality of row electrodes X1 to Xn and Y1 to Yn are grouped in a physical arrangement and divided into eight groups. At this time, the first to jth row electrodes are set to the first row group G ₁ , and the (j + 1) th to (2j) th row electrodes are set to the second row group G ₂ . In this manner, the (7j + 1) th to nth row electrodes are set to the eighth row group G ₈ (where j = n / 8). Alternatively, the row electrodes spaced apart at regular intervals may be set as a group, and the row electrodes may be grouped in an irregular manner as necessary.

And the first sub-field (SF11) is divided into a reset period (R11), an address period (WA11 ₁ ~WA11 ₈₎ and made of a holding period (S11 ₁ ~S11 _8), a first address period of the subfield (SF11) (WA11 _{1 to} WA11 ₈ are made of a selective write address. The second subfield to the last subfield SF12 to SF1L consist of address periods EA12 _{1 to} EA1L ₈ and sustain periods S12 _{1 to} S1L ₈ , and from the second subfield to the last subfield SF12 to SF1L. The address periods EA12 _{1 to} EA1L ₈ have a selective erase method. As described above, in the first embodiment, the plurality of subfields SF11 to SF1L include a subfield group of the selective writing method and a subfield group of the selective erasing method.

There are a selective writing method and a selective erasing method for selecting a discharge cell to emit light and a discharge cell not to emit light among a plurality of discharge cells. The selective write method is a method of selecting a discharge cell to emit light to form a constant wall voltage, and the selective erasing method is a method of selecting a discharge cell that will not emit light to erase a wall voltage already formed. That is, the selective writing method is a method of forming a wall charge by address discharge of a cell in a non-light emitting cell state and setting it as a light emitting cell state. The selective writing method is used to address a wall charge already formed by addressing a cell in a light emitting cell state. It is a method of erasing and setting to a non-light emitting cell state. In the subfield having the address period of the selective writing method, a reset period for initializing the light emitting cells to non-light emitting cells is generally formed immediately before the address period. In the following, the address discharge for forming the wall charge in the selective writing method is called "write discharge", and the address discharge for erasing the wall charge in the selective erasing method is called "erasure discharge".

Referring to FIG. 2 again, the first subfield SF11 having the address period of the selective writing method has a reset period R11 for initializing all discharge cells and setting them to the non-light emitting cell state. That is, in the reset period R11 of the first subfield SF11, first, the discharge cells of all the row groups G _{1 to} G ₈ are initialized and set to the non-light emitting cell state, and in the address periods WA11 _{1 to} WA11 ₈ . It is set in a state where address discharge is possible.

Then, the first sub-field (SF11) in the first to eighth row groups during the address period (WA11 ₁ ~WA11 _8), and a sustain period (S11 ₁ ~S11 ₈₎ of the (G ₁ ~G ₈₎ are performed sequentially. That is, the i is the sustain period (S11 _i) of the line group (G _i) the address period (WA11 _i) is performed, the i group (G _i) is performed after the. Subsequently, the address period WA11 _{i + 1} and the sustain period S11 _{i + 1 of} the (i + 1) th row group G _{i + 1} are performed.

Specifically, in the address period WA11 ₁ , the discharge cells set as the light emitting cells among the discharge cells of the first row group G ₁ are write-discharged to form wall charges, and the first row group G in the sustain period S11 ₁ . The light emitting cell of ₁ ) is sustained and discharged. Subsequently, in the address period WA11 ₂ , wall discharge is formed by writing and discharging the discharge cells set as light emitting cells among the discharge cells of the second row group G ₂ , and in the sustain period S11 ₂ , the second row group G _{2 is formed.} Sustain light discharge cell. At this time, sustain discharge also occurs in the light emitting cells of the first row group G ₁ . Similarly, for the other line group (G ₃ ~G ₈₎ during the address period (WA11 ₃ ~WA11 _8), and a sustain period (S11 ₃ ~S11 ₈₎ it is performed.

At this time, the i group (G _i) a sustain period (S11 _i) in the i th row group (G _i) the light-emitting cell and the first through the (i-1) line group (G ₁ ~G _i-1) of the The sustain discharge also occurs in the light emitting cell. The discharge cells of the _i th row group G _i set as light emitting cells in the first subfield SF11 are held just before the address period EA12 _i of the i th row group G _i of the second subfield SF12. The discharge is sustained until the periods S11 _{i to} S11 ₈ and S12 _{1 to} S12 _i-1 . That is, in the light emitting cells of the _i th row group G _i , sustain discharge occurs for a total of 8 sustain periods.

The address period of the next, the first to eighth row group in the second sub-field (SF12) having an address period of the selective erasing mode _{(G 1 ~G 8) (EA12} 1 ~EA12 8) , and a sustain period (S12 ₁ ~S12 ₈ ) is performed sequentially. That is, the i is the sustain period (S12 _i) of the line group (G _i) the address period (EA12 _i) is performed, the i group (G _i) is performed after the. Subsequently, the address period EA12 _{i + 1} and the sustain period S12 _{i + 1 of} the (i + 1) th row group G _{i + 1} are performed.

Specifically, in the address period EA12 ₁ , the discharge cells set as the non-light emitting cells of the light emitting cells of the first row group G ₁ are erased and discharged to erase the wall charges, and in the sustain period S12 ₁ , the first row group ( The remaining light emitting cells of G ₁ ) are sustained and discharged. Subsequently, in the address period EA12 ₂ , the discharge cells set as the non-light emitting cells of the light emitting cells of the second row group G ₂ are erased and discharged to erase the wall charges, and the second row group G is maintained in the sustain period S12 ₂ . The remaining light emitting cells in ₂ ) are sustained and discharged. At this time, sustain discharge also occurs in the light emitting cells of the first row group G ₁ . Similarly, remaining lines in the group (G ₃ ~G ₈₎ about the address period (EA12 ₃ ~EA12 _8), and a sustain period (S12 ₃ ~S12 ₈₎ is performed.

At this time, the i group (G _i) a sustain period (S12 _i) in the i th row group (G _i) the light-emitting cell and the first through the (i-1) line group (G ₁ ~G _i-1) of the The sustain discharge also occurs in the light emitting cell. And the i-th row group (G _i) of the light-emitting cell denotes a third sub-field (SF13) the i-th row group (G _i) the address period (EA13 _i) a sustain period of the immediately preceding _(i ~S11 ₈ S11, S12 ~ ₁ of Sustain discharge until S12 _i-1 ). That is, in the light emitting cells of the _i th row group G _i , sustain discharge occurs for a total of 8 sustain periods.

The remaining subfields SF13 to SF1L having the address period of the selective erasing method also have the same address periods EA13 _{1 to} EA13 ₈ , for each row group G _{1 to} G ₈ , similarly to the second subfield SF12 described above. ..., EA1L _{1 to} EA1L ₈ ) and the sustain periods S13 _{1 to} S13 ₈ , ..., S1L _{1 to} S1L ₈ are performed. In this way, the discharge cells set to the light emitting cells by the write discharge in the first subfield SF11 continue until they are set to the non-light emitting cells by the erase discharge in the address periods EA12 _{i to} EA1L _i of the subsequent subfields SF12 to SF1L. When the sustain discharge is performed and the non-light emitting cell becomes the erase discharge, the sustain discharge is not started from the subfield.

In the last subfield SF1L, in order to make the number of sustain discharges in each row group G _{1 to} G ₈ equal to each other, the _second subfield SF1L is once to each of the second to eighth row groups G _{2 to} G ₈ . Seven maintenance periods SA1 _{2 to} SA1 ₈ are additionally performed.

To this end, additional retention periods SA1 _{2 to} SA1 ₈ are formed in the last subfield SF1L for the second to eighth row groups G _{2 to} G ₈ , respectively. And additional sustain period (SA1 ₂ ~SA1 ₈₎ additional sustain period (SA1 ₂ ~SA1 ₈ of 8 times the sustain period in order to prevent sustain discharge in the groups of rows are performed, each row group (G ₂ ~G ₈₎ in The erasing periods ER1 _{1 to} ER1 ₇ for erasing the wall charges formed in the immediately preceding row groups G _{1 to} G ₇ are formed immediately before.

On the other hand, the eighth row group is (G ₈₎ may be formed in the erase period (ER1 ₈₎ for erasing wall charges in the additional sustain period (SA1 _8), even after the eighth row group (G ₈₎ a. In addition, since the reset period R11 is performed in the first subfield SF11 of the subsequent field, the erase period ER1 ₈ of the eighth row group G ₈ may not be formed. The erase operations in the erase periods ER1 _{1 to} ER1 ₈ may be sequentially performed on each row electrode of each row group as in the address period, or may be simultaneously performed on all row electrodes of each row group.

Specifically, after the sustain period S1L ₈ of the eighth row group G ₈ of the last subfield SF1L is performed, all discharge cells of the first row group G _{1 are} erased in the erase period ER1 ₁ . Eliminates wall charges that have formed. Then, in the sustain period SA1 ₂ , the light emitting cells of the second to eighth row groups G _{2 to} G ₈ are sustained and discharged. Then, after erasing the wall charges formed in all the discharge cells of the second row group G ₂ in the erasing period ER1 ₂ , the third to eighth row groups G ₃ in the sustaining period SA1 ₃ . It keeps discharging the light emitting cells of ~G _8). In this way, it is performed until the maintenance period SA1 ₈ . In this way, the number of sustain discharges in the light emitting cells of each row group G _{1 to} G ₈ is the same.

Next, a driving waveform used in the driving method of the plasma display device according to the first embodiment of the present invention will be described in detail with reference to FIG. 3.

3 is a view illustrating a driving waveform of a specific plasma display device of the driving method shown in FIG. 2. In FIG. 3, only the first and second row groups G ₁ and G ₂ and the first and second subfields SF11 and SF12 are illustrated for convenience of description, and the driving waveforms applied to the A electrode are not shown. The description of the driving waveform applied to the A electrode is also omitted.

As shown in FIG. 3, in the reset period R11 of the first subfield SF11, Y of all the row groups G ₁ and G ₂ in the state where a reference voltage (0 V in FIG. 3) is applied to the X electrode. The voltage of the electrode is gradually increased from Vs voltage to Vset voltage. Then, a weak reset discharge occurs between the Y electrode and the X electrode while the voltage of the Y electrode increases, and wall charges are formed in the discharge cells of all the row groups G ₁ and G ₂ . Subsequently, with the Vs voltage applied to the X electrode, the voltages of the Y electrodes of all the row groups G ₁ and G ₂ are gradually decreased from the Vs voltage to the Vnf voltage. Then, while a weak reset discharge occurs between the Y electrode and the X electrode while the voltage of the Y electrode decreases, the wall charges formed in the discharge cells of all the row groups G ₁ and G ₂ are erased and initialized to the non-light emitting cell. In general, the magnitude of the voltage (Vnf-Vs) is set near the discharge start voltage between the Y electrode and the X electrode. As a result, the wall voltage between the Y electrode and the X electrode becomes almost 0 V, thereby preventing the non-light emitting cell in which the address discharge has not occurred in the address period from being erroneously discharged in the sustain period.

In the address period WA11 ₁ , while the Vs voltage is applied to the X electrode, first, a scan pulse of the VscL1 voltage is sequentially applied to the plurality of Y electrodes of the first row group G1. At this time, an address pulse (not shown) having a positive voltage is applied to the A electrode of the discharge cell to emit light among the discharge cells formed by the Y electrode to which the scan pulse is applied. Then, write discharge occurs in the discharge cells to which the VscL1 voltage of the scan pulse and the positive voltage of the address pulse are applied, and wall voltages are formed on the X and Y electrodes to form light emitting cells. The Y electrode to which the scan pulse is not applied applies a VscH1 voltage higher than the voltage of the scan pulse, and a reference voltage is applied to the A electrode to which the address pulse is not applied, although not shown. At this time, the voltage VscH1 is also applied to the Y electrodes of the second to eighth row groups G _{2 to} G ₈ .

Next, in the sustain period S11 ₁ , the sustain discharge pulse of the voltage Vs is applied to the Y electrodes of all the row groups G ₁ and G ₂ to sustain discharge the light emitting cells. Subsequently, sustain discharge pulses of the voltage Vs are applied to the X electrodes of all the row groups G ₁ and G ₂ to sustain discharge the light emitting cells. In this case, first, because only the cells are light emitting cells, the discharge written in the address period (WA11 ₁₎ of the line group (G ₁₎ takes place, the first line group during the address period of the (G ₁₎ (WA11 ₁₎ only happened cell address discharge in Sustain discharge occurs.

While the sustain discharge pulse is applied to the X electrode, in the address period WA11 ₂ , the scan pulses of the VscL1 voltage are sequentially applied to the plurality of Y electrodes of the second row group G ₂ while the Vs voltage is applied to the X electrode. Is applied, an address pulse having a positive voltage is applied to the A electrode of the discharge cell to emit light among the discharge cells formed by the Y electrode to which the scan pulse is applied, and the cell in the non-light emitting cell state is discharged and set as the light emitting cell. do.

Next, in the sustain period S11 ₂ , the sustain discharge pulse of the voltage Vs is applied to the Y electrodes of all the row groups G ₁ and G ₂ to sustain discharge the light emitting cells. Subsequently, sustain discharge pulses of the voltage Vs are applied to the X electrodes of all the row groups G ₁ and G ₂ to sustain discharge the light emitting cells. In this case, the first and second groups of rows, so (G _1, G ₂₎ the address period, cells are light-emitting cells are discharged written in (WA11 _1, WA11 ₂₎ takes place in the first and second row groups (G _1, G ₂ Sustain discharge occurs in a cell in which address discharge has occurred in the address periods WA11 ₁ and WA11 ₂ . In this manner, an address period and a sustain period are performed for each row group in the first subfield SF11.

Next, in the address period EA12 ₁ of the second subfield SF12, scan pulses of the VscL2 voltage are sequentially applied to the plurality of Y electrodes of the first row group G ₁ while the reference voltage is applied to the X electrode. do. At this time, an address pulse (not shown) having a positive voltage is applied to the A electrode of the cell to be selected as the non-light emitting cell among the light emitting cells (cells in which sustain discharge has occurred in the first subfield) formed by the Y electrode to which the scan pulse is applied. do. A VscH2 voltage higher than the VscL2 voltage is applied to the Y electrode to which the scan pulse is not applied, and a reference voltage is applied to the A electrode to which the address pulse is not applied. Then, erase discharge occurs in the light emitting cell to which the VscL2 voltage of the scan pulse and the positive voltage of the address pulse are applied, so that the wall charges formed on the X electrode and the Y electrode are erased and set as the non-light emitting cell.

In the light emitting cell of the first subfield SF11, the cell in which the erasure discharge has not occurred in the address period EA12 ₁ of the second subfield SF12 is the light emitting cell of the second subfield SF12, and thus, the second subfield. In the sustain period S12 ₁ of the SF12, a sustain discharge pulse having a voltage of Vs is first applied to the X electrodes of the first and second row groups G ₁ and G _{2 to} generate sustain discharge in the light emitting cell, and then to the first electrode. And a Vs voltage is applied to the Y electrodes of the second row groups G ₁ and G ₂ to generate sustain discharge in the light emitting cells.

Then, in the address period EA12 ₂ , while a reference voltage is applied to the X electrode, a scan pulse of a VscL2 voltage, which is a negative voltage, is sequentially applied to the plurality of Y electrodes of the second row group G ₂ , and the scan is performed. An address pulse (not shown) having a positive voltage is applied to the A electrode of a cell to be selected as a non-light emitting cell among light emitting cells (cells in which sustain discharge has occurred in the first subfield) formed by the Y electrode to which the pulse is applied. Then, erase discharge occurs in the light emitting cell to which the VscL2 voltage of the scan pulse and the positive voltage of the address pulse are applied, so that the wall charges formed on the X electrode and the Y electrode are erased and set as the non-light emitting cell.

Subsequently, in the sustain period S12 ₂ , sustain discharge pulses of the voltage Vs are first applied to the X electrodes of the first and second row groups G ₁ and G _{2 to} generate sustain discharge in the light emitting cells, and then the first and second electrodes. The voltage Vs is applied to the Y electrodes of the row groups G ₁ and G ₂ to cause sustain discharge in the light emitting cells. In this manner, the address period and the sustain period are performed for the remaining row groups G _{3 to} G ₄ .

As described above, in the first embodiment of the present invention, since the address period is formed between the sustain periods of each row group, the priming particles formed in the sustain period can be fully utilized in the address period. Can be. In addition, since the voltage gradually increases and the voltage gradually decreases in the reset period, no strong discharge occurs in the reset period, and the contrast ratio can be increased because one reset period is performed for one field for every row group.

In the first embodiment, gray levels are represented by subfields having the same length of all subfields and continuously turned on from the first subfield. For example, in the second embodiment of the present invention, when the gray level when sustain discharge occurs only in one subfield is 1, and becomes a non-light emitting cell in the address period WA11 _i of the first subfield SF11, Since sustain discharge does not occur in the sustain period S11 _i and sustain discharge does not occur in the next subfields SF12 to SF1L, zero gray scale is represented. When a light emitting cell is generated in the address period WA11 _{i of} the first subfield SF11, since sustain discharge occurs in the first subfield SF11, one gray level can be expressed. Next, when an erase discharge occurs in the second subfield SF12 to become a non-light emitting cell, sustain discharge does not occur from the second subfield SF12. In addition, since the erase discharge is not generated in the second subfield SF12, since it is a light emitting cell, sustain discharge also occurs in the second subfield SF12 to express two gray levels. That is, the discharge cells which become light emitting cells in the first subfield SF11 and become non-light emitting cells in the K-th subfield SF1K are the first to the (K-1) th subfield SF1 (K). Since sustain discharge continues in -1)), the (K-1) gradation is finally expressed.

Meanwhile, in the first embodiment of the present invention, the address periods EA12 _{1 to} EA12 ₂ , EA13 _{1 to} EA13 ₈ ,..., EA1L ₁ of each row group in each subfield SF12 to SF1L of the subfield group of the selective erasing method. in ~EA1L ₈₎ it is set to about 0.3㎲ the width of the scan pulse applied to the Y electrodes of the row groups.

As described above, gray scales are represented by subfields that are turned on continuously from the first subfield. Thus, for example, 63 subfields are required to represent 64 gray scales. At this time, since the erase period and the additional sustain period are formed in the last subfield, assuming that the erase period and the additional sustain period are one subfield, a total of 64 subfields are required. If a subfield consisting of an erasing period and an additional sustaining period is assumed to be a subfield using the erasing method, a total of 63 subfields using the erasing method are obtained.

In the selective write method, the scan pulse has a width of 1.5 ms, the reset period is 350 ms, 20 sustain discharge pulses are entered in one subfield, and one sustain discharge pulse is 5 ms. Assuming that 480 row electrodes are driven under the condition, the first subfield SF11 takes 1170 ms (= 350 + (1.5 * 480) + (5 * 20)). Therefore, the time allocated to the subfield of the selective erasure method is 15496 ms (= 16666-1170). Since there are 63 subfields of the selective erasing method, one subfield is allocated 246 ms (= 15496/63). 146 ms (= 246-100) is allocated to the address period of one subfield. Since the number of row electrodes is 480, the width of the scan pulse should be 0.3 ms (= 146/480) or less in order to express at least 6 bits of gray by the combination of subfields.

In this manner, when the width of the scan pulse is set to 0.3 ms, the erase discharge may occur when the delay time of the erase discharge in the address period is 0.3 ms or less. However, the delay time of the erase discharge is affected by the priming particles formed by the previous sustain discharge. Therefore, if the scanning pulse is applied in the time range in which the priming particles formed by the sustain discharge are sufficiently left, the delay time of the erase discharge may be shorter than 0.3 ms.

Hereinafter, with reference to FIGS. 4A-4C, the time range after the sustain discharge which can set the delay time of erase discharge to 0.3 ms is demonstrated. 4A to 4C, discharge cells in which red (R) phosphors are formed on the plasma display panel 100 (hereinafter, referred to as “R discharge cells”) and green (G) phosphors in the plasma display panel 100 (hereinafter, referred to as “colors”) are used. It is assumed that a discharge cell (hereinafter referred to as a "B discharge cell") in which a "G discharge cell" and a blue (B) phosphor are formed is formed.

4A to 4C are diagrams showing the delay times of the erase discharges according to the time until the scan pulse is applied to the Y electrode after the last sustain discharge in the R, G and B discharge cells, respectively. In Figs. 4A to 4C, the green axis represents the erase discharge delay time, and the vertical axis represents the ratio of discharge cells in which erase discharge has not occurred. In the vertical axis, "1" indicates that erase discharge has not occurred in all discharge cells, and "0" indicates that erase discharge has occurred in all discharge cells.

4A to 4C, it can be seen that when a scan pulse is applied within a range of 20 ms, erase discharge occurs in a large number of discharge cells within 200 ms. Therefore, after the sustain discharge has occurred in the sustain period of any one row group, it is found that if the scan pulse is applied to all the Y electrodes of the next row group within the range of 20 ms, erase discharge occurs in all the discharge cells at 300 ms or less. Can be. That is, when the length of the address period of one row group is set to 20 ms or less, the width of the scan pulse can be set to 0.3 ms or less in the address period of the erasure method.

When the width of the scan pulse applied to the Y electrode of each row group in the erasure subfield is 0.3 ms and the address period of one row group is 20 ms, 66 (= 20/3) or less in one row group Row electrodes of may be included. For example, when there are 480 row electrodes, the number of row electrodes belonging to one row group may be set to 60 and all row electrodes may be divided into eight row groups.

On the other hand, in the first embodiment of the present invention, since grayscales are represented by subfields that are turned on continuously from the first subfield, a pseudo outline does not occur. However, since the number of subfields that can fit in one field is limited, the number of gradations that can be expressed only by the subfield is limited.

Hereinafter, a method of increasing the number of gray levels that can be expressed by a combination of subfields in one field will be described in detail with reference to FIG. 5.

5 is a diagram schematically illustrating a method of driving a plasma display device according to a second embodiment of the present invention.

As shown in FIG. 5, the driving method according to the second embodiment of the present invention divides a plurality of subfields SF21 to SF2M into two groups of subfields. In FIG. 5, the subfields of the first group include first to third subfields SF21 to SF23. At this time, the subfields SF21 to SF23 of the first group are formed temporally before the subfields SF24 to SF2M of the second group and include at least one subfield having respective weights. Similarly to the first embodiment, the subfields of the first group are driven by dividing the plurality of row electrodes into a plurality of row groups, and the address periods WA21 _{1 to} WA23 ₈ of the subfields of the first group are selectively written ( selective Write Address). Since the subfields SF24 to SF2M of the second group are the same as the subfields SF11 to SF1L of the second embodiment of the present invention, the description of the subfields SF24 to SF2M of the second group will be omitted below. .

Each subfield SF21 to SF23 of the first group having the address period of the selective writing method is similar to the first subfield SF11 in the second embodiment. However, in the subfields SF21 to SF23 of the first group, an erase operation for erasing wall charges formed in the discharge cells of each row group at the end of the sustain period of each row group is performed. Therefore, in the second embodiment, when the light emitting cells of the _i th row group G _i are sustained and discharged, the sustain discharge is also performed in the light emitting cells of the first to (i-1) th row groups G _{1 to} G _i-1 . Although this occurs, in the second embodiment of the present invention, the sustain discharge occurs only in the sustain period of the light emitting cells of the _i th row group G _i . Therefore, the weight of each subfield SF21 to SF23 of the first group corresponds to the length of the sustain period of one row group.

Specifically, in the reset period R21 of the first subfield SF21, the discharge cells of all the row groups G _{1 to} G ₈ are initialized and set to a non-light emitting cell state and set to a state in which address discharge is possible in the address period. do.

Subsequently, in the address period WA21 ₁ , the discharge cells to be set as light emitting cells among the discharge cells of the first row group G ₁ are write-discharged to form wall charges, and the first row group G ₁ in the sustain period S21 ₁ . Sustain light discharge cell. Then, the wall charges formed in the light emitting cells of the first row group G ₁ are erased. Then, the light emitting cells of the first row group (G ₁₎ emits light only in the sustain period (S31 ₁₎ of the first row group (G _1).

Next, in the address period WA21 ₂ , the discharge cells set as the light emitting cells among the discharge cells of the second row group G ₂ are write-discharged to form wall charges, and in the sustain period S21 ₂ , the second row group G _{2 is formed.} After sustain discharge of the light emitting cells, the wall charges formed in the light emitting cells of the second row group G ₂ are erased. In this manner, the address periods WA21 _{3 to} WA21 ₈ and the sustain periods S21 _{3 to} S21 ₈ are performed from the third row group G ₈ to the eighth row group G ₈ , and the first subfield ( The second and third subfields SF22 and SF23 are performed in the same manner as in SF21.

On the other hand, the light emitting cells of the first row of each group in each sub-field (SF21~SF23) of the group sustain period (S21 ₁ ~S21 _8), each row group after the (G ₁ ~G ₈₎ of the (G ₁ ~G ₈₎ in order to erase the wall charges formed in each line group (G ₁ ~G ₈₎ sustain period (S21 ₁ ~S21 ₈₎ so that the pulse width of the last sustain discharge pulse of the wall charges are not formed in the other sustain discharge pulses of the It can be implemented by making it narrower than. Alternatively, the wall charge formed by the sustain discharge may be erased using a waveform capable of gradually changing the voltage of the row electrode immediately after the last sustain discharge pulse (for example, a waveform changed in the form of a lamp).

The subfields SF21 to SF23 of the first group have reset periods R21, R22, and R23, respectively, so that the current cell can be set as a light emitting cell irrespective of the cell state in the immediately preceding subfield. Therefore, the discharge cells in the subfields SF21 to SF23 of the first group can be selectively sustained discharged. At this time, when the lengths of the relative holding periods S21 _{i to} S23 _i of the subfields SF21 to SF23 of the first group, that is, the weights are 1, 2 and 4, respectively, the subfields SF21 to SF23 of the first group In Equation 0, there are seven gray scales, that is, eight kinds of gray scales can be expressed. In the subfields SF24 to SF2M of the second group, the gray level is represented by the subfields which are sequentially turned on from the fourth subfield SF24 as described above. Therefore, the gray level in one field may be expressed by the sum of the gray level represented in the subfields SF21 to SF23 of the first group and the gray level represented in the subfields SF24 to SF2M of the second group.

For example, in the third embodiment, when there are 31 total subfields SF24 to SF2M in the second group, 32 gray levels may be expressed. If the length of each holding period of the subgroups SF24 to SF2M of the second group is set equal to the length of the holding period S21 _i of the minimum weighting subfield SF21 of the first group, The weights of the subfields SF24 to SF2M correspond to eight. Accordingly, gray scales corresponding to multiples of 8 may be expressed in the 0 to 248 (= 8 x 31) grays in the subfields SF24 to SF2M of the second group. Since the 0th to 7th gradations can be represented by the subfields SF21 to SF23 of the first group, the gradation from 0th to 255 (= is achieved by the combination of the subfields SF21 to SF2M of the first group and the second group. 248 + 7) Up to gradation can be expressed.

However, when the retention period is performed for each row group in each subfield SF21 to SF23 of the first group, when the total row group is divided into eight, a total of eight retention periods are performed. As a result, the length of the total sustain period in one subfield is long, which limits the number of subfields that can be used in one field.

Hereinafter, a method of reducing the number of sustain periods in each subfield SF31 to SF33 of the first group will be described in detail with reference to FIG. 6.

 6 is a diagram schematically illustrating a method of driving a plasma display device according to a third embodiment of the present invention.

As shown in FIG. 6, the driving method according to the third embodiment of the present invention is similar to the second embodiment. However, in the third embodiment, unlike the second embodiment, the discharge cells are formed by the plurality of row electrodes in one address period without grouping the plurality of row electrodes in each subfield SF31 to SF33 of the first group. Select the light emitting cell from among.

Specifically, in the address periods WA31 to WA33 of the subfields SF31 to SF33 of the first group, the discharge cells set as the light emitting cells among the discharge cells of the plurality of row electrodes are write-discharged to form wall charges. That is, after the address discharge is sequentially selected for the plurality of row electrodes in each address period WA31 to WA33, the light emitting cells are selected, and the sustain periods S31 to S33 are performed to generate sustain discharge. In this case, since one sustain period S31 to SF33 is performed in each subfield SF31 to SF33 of the first group, the sustain periods S31 to SF33 in each subfield SF31 to SF33 as compared with the third embodiment. ) Can be reduced in length. If the ratio of the lengths of the sustain periods S31 to SF33 of the subfields SF31 to SF33 is set to 1: 2: 4, and is set equal to the length of one sustaining period of the minimum weighted subfield SF31, In the same manner as in the third embodiment, gray levels may be expressed.

In the second and third embodiments of the present invention, a case in which the plurality of row electrodes are divided into eight row groups or not divided into row groups in the subfields SF21 to SF23 and SF31 to SF33 of the first group will be described. However, in the subfields SF21 to SF23 and SF31 to SF33 of the first group, the row electrodes may be divided into different number of row groups.

For example, a plurality of row electrodes may be divided into two row groups to form two address periods corresponding to each row group in each subfield of the first group. Alternatively, the number of row groups in the subfields of the first group may be divided into the number corresponding to the weight of each subfield.

In addition, in the second and third embodiments of the present invention, although the subfields SF21 to SF23 and SF31 to SF33 of the first group are shown before the subfields SF24 to SF2M and SF34 to SF3M of the second group, The subfields SF21 to SF23 and SF31 to SF33 of the first group may be located after the subfields SF24 to SF2M and SF34 to SF3M of the second group.

Further, in the first to third embodiments of the present invention, after sustaining discharge of the light emitting cells in the last row group of the last subfield SF1L, SF2M, SF3M of one field, the erase periods ER1 _2- ER1 ₈ , ER2 _2- ER2 ₈ , ER3 _{2 to} ER3 ₈ ) and additional retention periods SA1 _{2 to} SA1 ₈ , SA2 _{2 to} SA2 ₈ , SA3 _{2 to} SA3 ₈ are formed, but these may be deleted. When the erasing periods (ER1 _{2 to} ER1 ₈ , ER2 _{2 to} ER2 ₈ , ER3 _{2 to} ER3 ₈ ) and the additional holding periods (SA1 _{2 to} SA1 ₈ , SA2 _{2 to} SA2 ₈ , SA3 _{2 to} SA3 ₈ ) are deleted, The addressing order of each row group is changed through the fields of. Then, the number of sustain discharges in each row group can be the same.

Although the 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 an exemplary embodiment of the present invention, a plurality of subfields are divided into a plurality of subfield groups in one field, and a plurality of row electrodes are divided into a plurality of row groups and driven. In the first subfield of the first subfield group, the light emitting cells are selected by the selective writing method, and the non-light emitting cells are selected by the erasing method in the remaining subfields. At this time, an address period is formed between the sustain periods of each row group, and the priming particles formed in the sustain period can be sufficiently utilized in the address period, so that the width of the scan pulse can be shortened to perform high-speed scanning. In addition, a fast erase address is possible by appropriately limiting the length of the address period in the subfield of the selective erasure method.

Claims (15)

In a plasma display device including a plurality of row electrodes and a plurality of column electrodes for performing a display operation, and a plurality of discharge cells respectively defined by the row electrodes and the column electrodes, one field is driven by being divided into a plurality of subfields. In the method, Dividing the plurality of row electrodes into a plurality of row groups, dividing the plurality of subfields into a plurality of subfield groups, In each subfield of the first subfield group, selecting a non-light emitting cell among light emitting cells of each row group during a first address period for each row group of the plurality of row groups, and In each subfield of the first subfield group, sustain discharge of the discharge cells in the light emitting cell state of the plurality of row groups during a first sustain period positioned between two adjacent first address periods, And a length of the first address period for each row group of the plurality of row groups is within 20 ms. delete The method of claim 1, During the first address period of each row group, scan pulses are sequentially applied to the plurality of row electrodes of each row group, And a width of the scan pulse is 0.3 kW or less. The method of claim 3, After the light emitting cells of the last row group of the plurality of row groups are sustained discharged in the subfields that are positioned last in time in the first subfield group, Setting the light emitting cells of each row group to non-light emitting cells during an erase period for each row group of the plurality of row groups, and And sustain discharge of the discharge cells in the light emitting cell states of the plurality of row groups during an additional sustain period positioned between two adjacent erasing periods. The method of claim 3, In each subfield of the second subfield group, which is temporally preceding the first subfield group, and includes the plurality of row groups in the same number as the first subfield group, Selecting a light emitting cell among discharge cells of each row group during a second address period for each row group of the plurality of row groups, and In each subfield of the second subfield group, sustaining and discharging a discharge cell in a light emitting cell state of the plurality of row groups during a second sustain period positioned between two adjacent second address periods; A method of driving a plasma display device. The method of claim 5, And resetting the plurality of discharge cells to non-light emitting cells before selecting the light emitting cells in each subfield of the second subfield group. The method of claim 6, And a weight of each subfield of the first subfield group and a weight of each subfield of the second subfield group. The method of claim 5, In each subfield of the third subfield group, which is temporally ahead of the second subfield group and includes a plurality of subfields, Selecting a light emitting cell among discharge cells formed by the plurality of row electrodes during a third address period, and Sustaining and discharging the light emitting cells during a third sustaining period. The method of claim 5, Dividing the plurality of row electrodes into a plurality of row groups in each subfield of the third subfield group including a plurality of subfields having a respective weight and having a weight in front of the second subfield group; Selecting a light emitting cell among discharge cells of each row group during a fourth address period for each row group of the plurality of row groups, and In each subfield of the third subfield group, sustain discharge of the discharge cells in the light emitting cell states of the plurality of row groups for a fourth sustain period located between the adjacent fourth address periods. Method of driving the device. The method of claim 9, And in each subfield of the third subfield group, setting the light emitting cells of each row group to non-light emitting cells after sustaining and discharging the light emitting cells of each row group. The method of claim 10, The sum of the weights of each subfield of the third subfield group is one less than the weight of each subfield of the first and second subfield groups. A plurality of row electrodes including a first electrode and a second electrode to perform a display operation, and a plurality of column electrodes formed in a direction crossing the row electrodes, wherein the plurality of row electrodes and the plurality of column electrodes A plasma display panel in which a plurality of discharge cells are formed; A control unit that divides the plurality of subfields into a plurality of subfield groups, and divides the plurality of row electrodes into a plurality of row groups, and In each subfield of the first subfield group, non-light emitting cells are selected from among light emitting cells of each row group of the plurality of row groups during a first address period for each row group of the plurality of row groups, and two adjacent two A driving unit configured to sustain discharge discharge cells in the light emitting cell states of the plurality of row groups during a first sustain period between the first address periods; The driving unit sequentially applies a scan pulse having a width of 0.3 ㎲ or less to the plurality of row electrodes of each row group, and applies an address pulse to the column electrode of the light emitting cell to which the scan pulse is applied, thereby emitting the non-emission. A plasma display device for selecting a cell. The method of claim 12, And the control unit sets the length of the first address period to 20 ms or less. The method of claim 12, And the control unit sets up to 66 row electrodes in each row group of the plurality of row groups. The method according to any one of claims 12 to 14, The driving unit, In each of the subfields of the second subfield group consecutively preceding the first subfield group in time and including the plurality of row groups in the same number as the first subfield group, each of the plurality of row groups Selecting a light emitting cell among the discharge cells of each row group during the second address period for the row group, And in each subfield of the second subfield group, sustain discharge of the discharge cells in the light emitting cell state of the plurality of row groups during a second sustain period located between two adjacent second address periods.

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