KR100702052B1 - Plasma display panel device and the operating methode of the same - Google Patents

Abstract

The present invention relates to a plasma display device and a driving method thereof, and includes a driving unit for applying a driving waveform consisting of an address signal and a sustain signal to a scan electrode when a still image is displayed. Not applied can reduce power consumption and improve contrast ratio.

Plasma Display Panel, Reset, Contrast Ratio

Description

 Plasma display panel device and the operating method of the same}

1 is a view showing a structure of a plasma display panel according to the prior art;

2 is a view showing a plasma display panel driving waveform according to the prior art;

3A is a diagram showing a first embodiment of a plasma display panel drive waveform according to the present invention;

3B is a view showing a second embodiment of the plasma display panel driving waveform according to the present invention;

4A is a diagram showing a first embodiment of an initialization waveform applied to a plasma display panel according to the present invention;

4B is a diagram showing a second embodiment of an initialization waveform applied to a plasma display panel according to the present invention;

5 is a flowchart illustrating a method of driving a plasma display panel according to the present invention.

<Explanation of symbols on main parts of the drawings>

R: Reset signal A: Address signal

S: Sustain signal R_up: Setup reset signal

R_dn: set down reset signal R_pre: pre reset signal

The present invention relates to a plasma display device and a driving method thereof. In particular, when a still image is displayed, only the address signal and the sustain signal are applied to drive the plasma display panel, thereby preventing dark brightness from being increased by reset discharge. The present invention relates to a plasma display device and a driving method thereof.

1 is a diagram showing the structure of a conventional plasma display panel.

The plasma display panel is a display device in which a vacuum ultraviolet light (VUV) generated by discharging a gas inside the panel collides with a phosphor in the panel to generate light. The plasma display panel includes a front substrate 10 and a rear substrate 20.

As shown in FIG. 1, a typical plasma display panel includes a plurality of scan electrodes 11 and a sustain electrode 12 arranged in a stripe form to face the rear substrate 20. The dielectric layer 13 may be stacked to cover the scan electrode and the sustain electrode to limit discharge current during discharge and to easily generate wall charges, and a dielectric protective layer 14 formed of MgO to protect the dielectric layer.

In addition, the back substrate 20 is arranged in a stripe shape so as to be orthogonal to the scan electrode 11 and the sustain electrode 12 of the front substrate 10 so as to divide the entire screen into a plurality of cells together with the display electrode. An electrode 21, a dielectric layer 23 applied to the entire surface of the rear substrate to protect the address electrode and to perform electrical insulation, and a partition wall 22 formed in a stripe shape on the dielectric layer to form a discharge space; And a phosphor 24 which is printed and coated inside the discharge space formed by the barrier ribs and is excited by ultraviolet rays during the discharge of each cell to emit visible light.

The plasma display panel displays a screen through discharge in a plurality of address electrodes 21 arranged in a column direction and a plurality of scan electrodes 11 and sustain electrodes 11 arranged in a row direction. The waveform as shown is applied.

That is, when the plasma display panel is driven, a frame composed of a plurality of subfields is sequentially displayed, and the screen is displayed. The subfields include a reset signal R, an address signal A, and a sustain signal S, respectively.

Actual data is written while the address signal A is applied, and wall charges are accumulated in the discharged cell by selecting a cell that is discharged and a cell that is not discharged, and the address is applied when the sustain signal S is applied. Due to signal application, sustain discharge is actually performed on the addressed cells and the screen is displayed.

The reset signal R is applied to initialize each cell. The reset signal R is initialized by applying a high voltage to smoothly perform addressing before the address signal A is applied.

Therefore, in each subfield, initialization is performed by applying the reset signal R regardless of the addressing of each cell. When the reset signal is applied, a weak reset discharge is generated in the cell, and the dark luminance is lowered by a predetermined level or more. It becomes impossible.

Therefore, it is not possible to increase the contrast displayed by the ratio between the brightness of the brightest peak white and the brightness of the portion where no discharge is generated on the screen displayed on the plasma display panel.

That is, the brightness of the portion where the peak white is displayed is mainly determined by the light generated when the sustain signal S is applied, and the brightness is generated by applying the reset signal R. Since it is determined by the reset discharge, when the high-voltage reset signal is applied as described above, fine light is generated by the reset discharge, so that the contrast ratio cannot be increased.

In addition, since the dark portion is excited by the light generated by the reset discharge, there is a problem that it is difficult to accurately represent the color in the plasma display panel.

The present invention has been made to solve the above-described problems of the prior art, and when the still image is displayed, only the address signal and the sustain signal are applied to increase the brightness and, as a result, discharge due to the reset signal does not occur, the dark brightness. The present invention provides a plasma display device and a method of driving the same, which can improve contrast ratio by removing the?.

The plasma display device according to the present invention for solving the above problems is characterized in that it comprises a drive unit for applying a drive waveform consisting of an address signal and a sustain signal to the scan electrode when the still image is displayed.

In addition, the driving method of the plasma display apparatus according to the present invention includes a first step of applying an address signal to a scan electrode and a second step of applying a sustain signal to the scan electrode when a still image is displayed. It is done.

Hereinafter, a plasma display device of the present invention will be described with reference to the accompanying drawings. 3A and 3B are diagrams illustrating driving waveforms of the plasma display panel according to the present invention, and FIGS. 4A and 4B are diagrams illustrating embodiments of the initialization waveform applied to the plasma display panel according to the present invention.

The plasma display panel according to the present invention includes a module including a plurality of address electrodes X arranged in a column direction, a plurality of scan electrodes Y arranged in a row direction, and a sustain electrode Z. . The scan electrode is formed corresponding to each sustain electrode, and one end of the sustain electrode is connected to each other, and the same voltage is applied thereto.

The module is formed by bonding a front panel on which the scan electrode Y and the sustain electrode Z are alternately horizontally formed, and a rear panel on which the address electrode X is formed. The scan electrode, the sustain electrode and the address electrode are disposed to face each other with the discharge space interposed so as to vertically intersect, and the discharge space at the intersection of the scan electrode and the sustain electrode and the address electrode may form one basic discharge cell. Form.

The plasma display panel drives one frame by dividing one frame into one or more subfields SF having different number of discharges in order to express gray scale. Generally, the subfields have a reset signal R for largely initializing discharge cells. ) Is a reset period to which the signal is applied, an address period to which the address signal A for data writing is applied, and a sustain period to which the sustain signal S is applied to display an image through sustain discharge.

The reset signal R includes a setup reset signal R_up in which a ramp type voltage increases and a set down reset signal R_dn in which a voltage decreases. When the setup reset signal is applied, the reset discharge is generated in the discharge cell, thereby increasing the dark brightness. Therefore, when the still image is displayed, the plasma display device of the present invention displays the address signal A and each subfield SF. And a driving unit for applying a driving waveform consisting of the sustain signal S to the electrodes.

That is, as shown in FIG. 3A, one subfield SF includes only an address section to which the address signal A is applied and a sustain section to which the sustain signal S is applied. Therefore, in the case of the cell in which the discharge is generated, the cell generated in the discharge is selected by the address signal, and the sustain discharge is generated by the sustain signal to display the screen.

The driver applies the bias voltage Vzb of a predetermined voltage level to the sustain electrode Z while applying the address signal A to the scan electrode Y during the address period. The address discharge between the scan electrodes is made stable.

The driving unit applies a sustain pulse of a sustain voltage level Va to the scan electrode Y during the sustain period. At the same time, a sustain pulse of the same voltage level is applied to the sustain electrode Z alternately with the sustain pulse applied to the scan electrode. When a sustain pulse is applied to the scan electrode Y and the sustain electrode Z, a sustain discharge is performed by the voltage difference between the scan electrode and the sustain electrode to display a screen.

If a still image is displayed, each discharge cell displays the same gray level every frame. Therefore, in the case of a cell in which discharge is generated, no false discharge occurs even when the reset signal R is not applied and initialization is not performed, and sufficient brightness can be secured without a problem in which a strong discharge occurs in a specific cell and the bright point is splashed. Will be.

On the contrary, since the reset signal R is not applied to a cell in which no discharge is generated, the reset discharge is not generated, thereby preventing the generation of fine light during the reset period, and thus the dark brightness is 0 cd / cm 2, so that Contrast is ∞: 1.

In general, when the still image is displayed, the screen is displayed by applying the reset signal R, the address signal A, and the sustain signal S to each subfield SF as in the case of displaying the moving image.

That is, the reset signal R is applied during the reset period to initialize all the cells. The reset signal includes a setup reset signal R_up and a set down reset signal R_dn. When the setup reset signal is applied, excess wall charges are formed in each of the cells, and a set down reset signal is applied to erase part of the wall charges generated to form the same level of wall charges in all cells.

In this case, when the setup reset signal R_up is applied, reset discharge is generated in each cell. Therefore, even in the case of a cell in which no sustain discharge is generated due to no data writing during the address period A, a slight light is generated.

In contrast, in the present invention, one subfield SF includes only an address section and a sustain section. Therefore, when the plasma display panel is driven using the plasma display apparatus of the present invention, when the still image is displayed as described above, each cell expresses the same gray level every frame, so that the address signal A is not applied without the reset signal R. ) And the sustain signal S are applied to display the screen.

Here, the driver may be configured to further apply a set down reset signal R_dn before applying the address signal A and the sustain signal S, as shown in FIG. 3B.

In the case of a cell in which discharge is generated, the same gray level is expressed in every frame, but for each subfield SF constituting the frame, each cell does not discharge the same in every subfield. That is, sustain discharge occurs in some subfields and sustain discharge occurs in some subfields.

Therefore, when the set-down reset signal R_dn is applied, in the case of the cell in which the discharge occurred in the previous subfield SF, the wall charges or priming particles accumulated in the cell by the discharge are initialized.

When the still image is displayed, the cells to be turned on for each frame are always the same. Thus, as the cells have been discharged, a strong reset discharge is generated by applying a high-voltage setup reset signal R_up as in a conventional plasma display device to generate a discharge cell. There is no need to initialize it.

However, when the set down reset signal R_dn is applied, the wall charges or priming particles formed inside the cells are stably rearranged so that each discharge cell maintains a constant brightness at all times without a bright point or a flashing problem every frame. Can be implemented.

Also, even when the set down reset signal R_dn is applied before the address signal A and the sustain signal S are applied to each discharge cell, no reset discharge occurs between the scan electrode Y and the sustain electrode Z. . Accordingly, only the wall charges or priming particles inside the cells discharged in the previous subfield SF are initialized, and in the case of the cells not discharged, the previous state is continuously maintained so that the dark luminance of 0 cd / cm 2 is continuously maintained. A contrast ratio of ∞: 1 is achieved.

As such, when the still image is displayed, the dark luminance may be removed because the cell initialization through the reset discharge is not performed in each cell of the plasma display panel while maintaining the brightness because the setup reset signal R_up is not applied. .

In particular, when the still image is displayed by applying all of the conventional reset signal R, the address signal A, and the sustain signal S, the contrast ratio is increased by increasing the number of sustain pulses applied during the sustain period. Raised.

In this case, the number of sustain pulses applied during the sustain period is limited, thereby improving the brightness, and maximizing sustain discharge for only a specific cell, thereby causing partial deterioration of the plasma display panel, thereby decreasing panel uniformity.

Even when the number of sustain pulses is increased, the dark luminance does not become 0 cd / cm 2 due to the reset discharge, and the contrast ratio cannot be improved by more than several thousand units: 1.

On the other hand, when displaying the still image by applying only the address signal (A) and the sustain signal (S) without applying the reset signal (R) as in the present invention, as well as removing the dark luminance at 0 cd / ㎠, It is possible to prolong the life of the plasma display panel by preventing deterioration of only the cell.

In addition, the plasma display apparatus may include an initialization driver configured to apply an initialization waveform including an reset signal R 'and an address signal A' to electrodes before or after the pattern of the screen displayed on the plasma display panel is changed. It is configured to further include.

In this case, the subfield SF 'applied by the initialization driver is composed of a reset section to which a reset signal R' is applied and an address section to which an address signal A 'is applied, and one frame includes at least one frame. It is configured to have the above subfields.

That is, the initialization driver uses only the reset signal R 'and the address signal A' as described above before displaying the screen using the subfield SF composed of only the address signal A and the sustain signal S. The plasma display panel is initialized by applying one or more times to the subfield SF '.

As shown in FIG. 4A, when the reset signal R 'and the address signal A' are applied, reset discharge occurs to initialize the cell. When the setup reset signal R_up 'is applied, negative charge is formed on the scan electrode Y, and positive charge is formed on the sustain electrode Z.

Subsequently, when the set-down reset signal R_dn 'is applied to the scan electrode Y, the wall charges formed on the scan electrode and the sustain electrode Z are erased by voltage reduction, so that the address discharge is performed during the subsequent address period. Wall charges are formed.

Also in this case, while the address signal A 'is applied to the scan electrode Y, a bias voltage of a predetermined voltage level is applied to the sustain electrode Z, and thus the scan electrode Y and the address electrode ( The address discharge between X) is performed stably.

In the plasma display device of the present invention, after the initialization driver has applied an initialization waveform consisting of only the reset signal R 'and the address signal A' about 2 to 3 times, the drive unit has an address signal A and a sustain signal ( It is preferable to apply a driving waveform consisting of S) to display a still image.

That is, since the discharge cell is initialized by applying the reset signal R 'and the address signal A' before the still image display, addressing is stable when the address signal A and the sustain signal S are applied. This allows the screen to be displayed without compromising image quality.

In addition, the initialization driver applies a driving waveform consisting of only the address signal A and the sustain signal S to the reset signal R 'and the address signal A' only after the still image is displayed. It can be configured to initialize the discharge cell by applying an initialization waveform made.

After one still image is displayed, all discharge cells are initialized even when a still image of another pattern is displayed or a video is displayed. Thus, even when the reset signal R is not applied, an error discharge or a strong discharge occurs. It can eliminate the phenomenon of bright spot.

In addition, as shown in FIG. 4B, the initialization driver has a negative shape similar to the set-down reset signal R_dn 'to the scan electrode Y before the reset signal R' and the address signal A 'are applied. The polarity pre-set signal R_pre 'is applied to enable effective initialization of the discharge cells. At this time, a voltage of a predetermined level is also applied to the sustain electrode Z to perform a pre-reset.

In order to display gradation, one frame is composed of subfields SF having different numbers of sustain pulses applied during the sustain period. In order to express gradation of 256 levels, at least 8 subframes Has a field

However, in order to initialize the discharge cells, the discharge cells are initialized by performing one or more times a frame having one or more subfields SF '. For effective initialization, at least two to three or more subfields SF' are configured. Perform one or more frames.

In this case, when the frame has three or more subfields SF ', the pre-reset signal R_pre' is applied only during the initial one to three subfields so as to effectively initialize the discharge cells.

5 is a flowchart illustrating a method of driving a plasma display device according to the present invention. The operation of the plasma display device of the present invention will be described with reference to FIG. 5 as follows.

When the still image is displayed, an address signal is first applied in the first step (S6). An address signal having an address voltage is applied to the address electrode, and a scan voltage is applied to the scan electrode corresponding to the point in time at which the address signal is applied to select a cell to be discharged.

In this case, a negative set down reset signal is applied to the scan electrode before the first step (S5). In the still image, since each discharge cell represents the same gray level every frame, it is not necessary to initialize the discharge cell through a strong reset discharge by applying a setup reset signal to the discharge cell. As described above, even if only the set-down reset signal is applied, the wall charge or priming already formed in the discharge cell is initialized, so that there is no problem in displaying the screen through the sustain discharge.

In other words, the cells that are always turned on always turn on at the same brightness, and the cells that are turned off are always turned off constantly. Therefore, a reset discharge signal is applied to generate a reset discharge to excessively generate wall charge, and a setdown reset signal is applied to the wall. There is no need to erase the charge so that it is formed only as necessary for the address discharge. When the set down reset signal is applied without applying the setup reset signal, the arrangement of the wall charges used in the previous discharge is stabilized, and the address discharge is performed when the address signal is applied.

The plasma display apparatus driving method may further include performing initialization (S3, S4) by applying the reset signal and the address signal one or more times before displaying the still image.

If the reset signal is applied, the discharge cells are initialized through the reset discharge, so that the wall telephones formed in the respective discharge cells are initialized according to the previously displayed pattern. Therefore, when the pattern of the displayed still image is changed, it is possible to prevent the screen from being displayed late, or mis-discharge, blinking, or bright spots.

Here, when the address signal is applied to the scan electrode, a bias voltage of a constant voltage level may be applied to the sustain electrode to stably generate an address discharge between the scan electrode and the address electrode.

In addition, before the reset signal is applied to the scan electrode, a pre-reset signal having a negative polarity is applied (S1, S2), and a predetermined level of voltage is applied to the sustain electrode to perform a pre-reset. Priming particles are sufficiently produced. Therefore, when the reset signal is applied, the discharge cell initialization may be smoothly performed.

In the second step, a sustain signal is applied to the scan electrode and the sustain electrode (S7). At this time, a voltage of the same level is alternately applied to the scan electrode and the sustain electrode, so that the sustain discharge is generated in the cell selected in the first step. Is generated and the screen is displayed.

In addition, in the method of driving the plasma display device of the present invention, after the second step, the reset signal and the address signal are applied one or more times to perform initialization (S8 to S11).

After displaying one pattern and performing initialization by applying a driving waveform consisting of a reset signal and an address signal to the scan electrode and the sustain electrode, all discharge cells are initialized before other patterns are displayed. It is possible to prevent erroneous discharge from occurring during display.

If the screen is displayed by continuously performing addressing and sustain discharge only without performing initialization in the still image as described above, the reset discharge does not occur in the case of the off-cell in which the discharge does not occur, so that the brightness is removed and the contrast ratio of the plasma display panel is eliminated. In addition to improving the problem, the flashing may occur due to the reset discharge or the bright spot may be solved.

As described above, the plasma display device and the driving method thereof according to the present invention have been described with reference to the illustrated drawings. However, the present invention is not limited by the embodiments and drawings disclosed herein, and the scope of the technical idea of the present invention is protected. The application is possible by those skilled in the art within.

The plasma display device and its operation method according to the present invention configured as described above display a screen by applying only an address signal and a sustain signal without applying a reset signal when a still image is displayed, thereby increasing the brightness while simultaneously increasing the brightness. In addition to improving the contrast ratio by controlling, there is an effect of improving the image quality of the plasma display panel by eliminating the generation of bright spots.

Claims (15)

And a driving unit for applying a driving waveform consisting of only an address signal and a sustain signal when the still image is displayed. The method of claim 1, And the driving waveform further comprises a set down reset signal applied before the address signal. The method of claim 1, And the driving unit applies a bias voltage to the sustain electrode while the address signal is applied to the scan electrode. The method of claim 1, And the driving unit applies a sustain pulse to the sustain electrode alternately with the scan electrode while the sustain signal is applied to the scan electrode. The method of claim 1, And the plasma display apparatus further comprises an initialization driver for applying an initialization waveform consisting of a reset signal and an address signal to the scan electrode before the driving waveform is applied. The method of claim 1, The plasma display apparatus further comprises an initialization driver for applying an initialization waveform consisting of a reset signal and an address signal to the scan electrode after the driving waveform is applied. The method of claim 1, The plasma display apparatus further comprises an initialization driver for applying an initialization waveform consisting of a reset signal and an address signal to the scan electrode before and after applying the driving waveform. The method according to any one of claims 5 to 7, And the initialization driver applies a bias voltage to the sustain electrode while an address signal is applied to the scan electrode. The method according to any one of claims 5 to 7, And the initialization driver applies the initialization waveform to one or more subfields. The method according to any one of claims 5 to 7, And the initialization waveform further comprises a pre-reset signal applied before the reset signal. The method of claim 10, And the initialization driver applies a predetermined level of voltage to the sustain electrode while a pre-reset signal is applied to the scan electrode. delete delete delete delete

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