KR100755401B1 - Plasma display panel device and the operating method of the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel device and a method of driving the same, wherein a maximum voltage level of a setup signal and a setdown signal applied during a reset period, and a voltage of the setup signal and the setdown signal are applied to a cell displaying an on screen display (OSD). And a pulse driver configured to vary the number of times of application, wherein the setup signal and the set-down signal are composed of signals having at least one slope during a reset period, so that the number and voltage levels of the reset signals applied to the cells on which the OSD is displayed are displayed. Can be reduced than if it is displayed to eliminate afterimages.

Plasma Display Panel, OSD, Afterimage, Sustain, Setup, Reset

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;

3 is a view illustrating an OSD on a plasma display panel according to the present invention;

4 is a view showing a driving waveform applied to the plasma display panel according to the present invention;

5 is a view showing a signal constituting one frame for driving a plasma display panel according to the present invention;

6 is a view showing the number of sustain pulses varying when the plasma display panel is driven according to the present invention.

<Explanation of symbols on main parts of the drawings>

R: Reset signal A: Address signal

S: Sustain signal R ₁ : Setup signal

R ₂ : Set down signal

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel device and a method of driving the same, and in particular, a plasma display capable of eliminating an afterimage by reducing the number of setup signals and sustain pulses applied to a cell on which an OSD is displayed, compared to when a video is displayed. A panel 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.

In a typical plasma display panel, as shown in FIG. 1, the front substrate 10 includes a plurality of scan electrodes 11 and sustain electrodes 12 that are arranged in a stripe form to face the rear substrate 20. The dielectric layer 13 is laminated to cover the scan electrode and the sustain electrode to limit the discharge current during discharge and facilitate the generation of wall charges, and the dielectric protective layer 14 formed of MgO for protecting 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.

The driving waveform includes a reset signal (R), an address signal (A), and a sustain signal (S). The reset signal is 250V to the scan electrode 11 to initialize a discharge cell by applying a high voltage. Apply the above high voltage.

The address signal A is applied to each discharge cell for image writing. An address voltage Va having a positive polarity is applied to the address electrode 21, and the address is applied to the scan electrode 11. When a pulse Vy having a polarity opposite to the voltage applied to the electrode is applied to generate an address discharge, and the sustain signal S is applied, a cell to generate a discharge is selected.

The sustain signal S is applied to the scan electrode 11 and the sustain electrode 12 to alternately apply a pulse Vs signal having opposite polarity to generate a sustain discharge to display a screen.

If an OSD (On Screen Display) is displayed on the plasma display panel, most of the remaining areas except the partial display area of the OSD are black areas in which the discharge cells are not turned on.

At this time, when the OSD display is finished, since the discharge cells of the portion where the OSD is displayed are discharged for a long time, an afterimage occurs due to phosphor degradation.

When the OSD is displayed to reduce the afterimage generated after the OSD ends, the afterimage may be reduced by applying the reset signal R applied to the plasma display panel only in a specific subfield instead of every subfield. In this case, when the video is played, the discharge cells are not initialized sufficiently in the low gradation part, so that the screen is broken or an error is generated.

The present invention has been made to solve the above-mentioned problems of the prior art, and in the case of a cell displaying an OSD, by reducing the number of reset signals and voltage levels applied during one frame period, the number of sustain pulses is varied. A plasma display panel device capable of eliminating an afterimage and a driving method thereof are provided.

The plasma display device according to the present invention for solving the above problems is the maximum voltage level of the setup signal and the set-down signal applied during the reset period, and the setup signal and the set down for the cell displaying the OSD (On Screen Display) And a pulse driver configured to vary the number of times of applying the signal, wherein the setup signal and the setdown signal are configured as signals having at least one slope during a reset period.

In addition, the driving method of the plasma display panel apparatus according to the present invention is different from the driving signal supplied for one frame in the mode in which the OSD is displayed and the mode in which the image signal is displayed, and according to the gray level value of the OSD to be displayed during the one frame. The OSD mode includes a step of determining the number of sustain pulses, and adjusting the number of times or maximum voltage level of a setup signal or a setdown signal supplied to the cell on which the OSD is displayed during one frame when the number of sustain pulses is equal to or greater than a predetermined reference value. Driven.

Hereinafter, a plasma display panel driving apparatus of the present invention will be described with reference to the accompanying drawings.

On Screen Display (OSD) is a display device itself displayed on the screen without the input of a separate image signal, the user needs to know or need, and collectively referred to operations and screen display related to various setting items.

As shown in FIG. 3, when the video signal cable is not correctly connected, a message such as "Please check the connection" is displayed, or when no signal is applied to the display device, a message (a) such as "No signal" is displayed. In addition, all the operation screens (b) appearing on the screen when various setting operations are performed using the operation buttons on the front of the display device may be referred to as OSDs.

When such an OSD is displayed, an area other than the portion (①) where the OSD is displayed becomes a black area (②) where discharge does not occur. If the OSD is displayed for a long time and then disappears, the previously displayed OSD remains as an afterimage. .

That is, when the OSD is displayed, the same driving waveform is continuously applied. In this case, since the discharge cells of the portion (①) on which the OSD is displayed perform the same discharge every frame, the discharge is performed in the specific discharge cell where the discharge is performed. Priming particles for performing the operation is increased, which causes the deterioration of the phosphor and causes an afterimage problem in which the previously displayed image remains even when the OSD display is terminated.

To this end, the plasma display panel driving apparatus of the present invention includes a pulse driver for varying the number of setup signals applied in the reset period, the set down signal, and the number of sustain pulses applied during the sustain period when receiving the OSD signal for displaying the OSD. It is configured by.

The pulse driver generates a control signal by analyzing and synchronizing the R / G / B image signal and is implemented on a control board for controlling the operation of the entire plasma display panel. In general, the control board displays an OSD when receiving a signal for the OSD display from the image board, so that the pulse driver varies the number of reset signals applied during the reset period when receiving the OSD signal from the image board.

The plasma display panel drives one frame by dividing one frame into at least one subfield having a different number of discharges in order to express gray scale. The subfield includes a reset section R to which a reset signal is applied, an address section A to which an address signal is applied, and a sustain section S to which a sustain signal is applied. R ₁ ) and the set down signal R ₂ .

The reset signal is a signal applied equally to all the discharge cells regardless of whether the discharge cells are on or off in the previous subfield, and has a high voltage of 250 V or higher to the scan electrode Y to make all the discharge cells the same. Is applied. When the reset signal is applied to the scan electrode, all the discharge cells are initialized. In this case, a reset signal in the form of a ramp waveform is mainly applied in order to improve contrast.

As shown in FIG. 4, the setup signal R ₁ gradually increases the voltage to apply a high voltage to the scan electrode to increase the amount of wall charge generated between the scan electrode Y and the sustain electrode Z. . The set down signal R ₂ gradually decreases the voltage applied to the scan electrode to reduce the wall charge formed between the scan electrode and the sustain electrode to a certain amount. In this case, the setup signal and the set down signal have a form of a ramp waveform having at least one slope.

The same discharge mechanism is always performed in the cells ① of the area where the OSD is displayed. Each cell displays the same brightness of each gray level. At this time, when the setup signal R ₁ is applied to generate wall charges in the cell in every subfield, a large amount of wall charges are continuously generated in the cell and the afterimage phenomenon is intensified.

Therefore, when the OSD display is finished, the pulse driver changes a reset signal applied to the cell on which the OSD is displayed in order to prevent an afterimage from remaining in the region ① where the OSD was displayed.

The pulse driver changes the number of reset signals so that the number of reset signals applied to the cell on which the OSD is displayed during one frame period is smaller than when the moving image is displayed. In particular, the setup signal R is applied during one frame period. Reduce the number of ₁ ).

Since the afterimage phenomenon is mainly influenced by the setup signal R ₁ of the reset signals, the pulse driver reduces the total number of reset signals applied during one frame period or the setup signal or set down signal R _2. ) Will be reduced.

Discharge cell initialization is not properly performed unless the reset signal is applied to all subfields constituting one frame. Therefore, at least one reset signal is applied. If too many reset signals are applied, phosphor degradation is increased. Since the afterimage improvement effect is eliminated, the reset signal is applied within one to six ranges.

At this time, since the wall charge is generated by the reset discharge in the discharge cell when the setup signal R ₁ is applied, an afterimage improvement effect may be obtained even by reducing only the number of the setup signals R ₁ applied during one frame period. . In the case of the cell in which the discharge occurred in the previous subfield, when the set down signal R ₂ is applied, the wall phone disturbed by the discharge is stably rearranged, so that the screen is displayed even when only the set down signal is applied without the setup signal. There will be no problem.

For example, assuming that one frame is composed of 12 subfields, as shown in FIG. 5, the reset signal is applied to the initial two subfields and not to the remaining subfields. .

In addition, since the afterimage is influenced by the setup signal R ₁ that generates a wall charge inside the discharge cell by applying a high voltage to initialize the discharge cell, the pulse driver is a signal applied to the cell displaying the OSD during the reset period. The maximum voltage level is lower than when the video is displayed.

That is, during the reset period, a high voltage is applied to the scan electrode to generate a reset discharge to generate wall charges inside the cell, thereby performing initialization, and the afterimage is generated by phosphor degradation due to wall charges and discharges formed inside the cell. By lowering the voltage level of the reset signal, a weak reset discharge can be generated to improve the afterimage.

In particular, the size of the setup signal R ₁ may be smaller than that of a moving image, thereby limiting wall charges generated according to the application of the setup signal, thereby improving the afterimage.

In general, one frame generates sustain discharges of about 1000 times. In the area where the OSD is displayed, the bright screen is continuously displayed, and in the case of the black area where the OSD is not displayed, the discharge does not occur. Afterimage is generated by sustain discharge.

Therefore, as shown in FIG. 6, the pulse driver reduces the number of sustain discharges so that the number of sustain discharges of the cell on which the OSD is displayed is smaller than the cell Max on which the video is displayed. Accordingly, since the sustain discharge occurring during one frame is reduced, it is possible to reduce phosphor degradation and to improve afterimages.

At this time, if the number of sustain discharges is too large, the afterimage improvement effect is eliminated. Therefore, the number of sustain discharges is 500 or less. If the number of sustain discharges is too small, the contrast ratio and luminance decrease, so the number of sustain discharges is 200 or more (Min). Be sure to

The number of sustain discharges varies depending on the number of sustain pulses applied during the sustain period. When the sustain pulse S is applied to the scan electrode Y and the sustain electrode Z during the sustain period, sustain discharge is generated. Decreasing the number of sustain pulses applied during the period also reduces the number of sustain discharges. If the number of sustain pulses increases, the number of sustain discharges also increases.

That is, the pulse driver is configured to vary the number of sustain pulses applied to the cell displaying the OSD during the sustain period, wherein the number of the sustain pulses applied to the cell displaying the OSD is displayed during the at least one frame period. The number of sustain pulses applied to the cell displaying the number is less than to prevent the degradation of the phosphor.

When the OSD is displayed, since the average brightness of the input image is dark, in general, the number of sustain pulses S applied during one frame increases. As the number of sustain pulses increases, a strong discharge occurs, and the phosphor deterioration is further increased, thereby leaving an afterimage.

However, in the case of the cell of the area ① displayed on the OSD, the same gray level is expressed every frame, so that the afterimage can be improved while maintaining the screen brightness without increasing the number of the sustain pulses S.

In general, the plasma display panel adjusts the number of sustain pulses S applied during one frame period according to the average brightness of the input image. That is, in the case of low gradation according to Average Picture Level (APL), the number of sustain pulses according to APL is increased to increase the number of sustain discharges generated during one frame period to increase the dark display power and In this case, the number of sustain pulses according to APL is reduced because the screen can be expressed even if a small number of sustain pulses is applied.

For example, assuming that the APL is divided into 1024 levels from the 0 level to the 1023 level, when the OSD is displayed as described above, the average brightness of the entire screen is low and is included in the low gray level between the APL 10 and 13 levels. Therefore, in the related art, when the OSD is displayed, the afterimage phenomenon is further increased by adjusting the number of the sustain pulses S applied during one frame to about 1000.

However, if a large number of sustain pulses is applied as described above, the display power is increased at low gradations, but when the same screen is displayed for several seconds, the discharge is continuously generated only in the cell where the discharge occurs.

Therefore, the pulse driver reduces the number of reset signals and sustain pulses applied when the number of the maximum sustain pulses S according to the APL is 500 or more, and varies the magnitude of the voltage level of the reset signal.

That is, when the number of the maximum sustain pulses according to the APL is 500 or more, since the average brightness of the displayed screen is low, the sustain efficiency S is generally applied to increase the discharge efficiency. However, when the OSD is displayed as in the present invention, the displayed OSD only needs to have a predetermined brightness or more, so that the number of sustain pulses applied during one frame period is 500 or less.

 As described above, when the number of sustain pulses S applied during one frame period decreases, the number of sustain discharges that can occur to the maximum decreases, thereby eliminating afterimages caused by sustain discharge.

At the same time, when the number of the sustain pulses S applied to the cell on which the OSD is displayed during one frame period according to the APL is 500 or more, the sustaining unit is applied during one frame period according to the APL. The reset signal is applied less than when the number of pulses S is 500 or less.

The pulse driver changes the number of sustain pulses S and the number of reset signals applied during one frame period differently from the case where a video is displayed in the cell in which the OSD is displayed.

When the number of sustain pulses S according to the APL is 500 or more, the pulse driver reduces the number of reset signals applied during one frame. In addition, the sustain pulse S applied during one frame is not determined by the APL.

That is, if the number of sustain pulses S applied to the pulse driver during one frame period according to APL of the input image is 500 or more, the number of reset signals applied during one frame is less than that when the video is displayed. The number of sustain pulses applied during one frame period is 500 or less.

At this time, the number of reset signals applied during one frame period is about 1 to about 6, in particular, the pulse driver applies the set down signal R ₂ as it is and reduces only the number of setup signals R ₁ . Can be.

In addition, the pulse driver causes the maximum voltage level of the signal applied during the reset period to the cell on which the OSD is displayed to be smaller than the cell on which the video is displayed.

In the case of the cell on which the OSD is displayed, the same gray level is expressed every frame. Therefore, as shown in the video display, a high voltage is not applied to completely initialize the discharge cell, and only a set down signal R ₂ below the ground voltage level is applied. Even if only the disturbed wall charge arrangement is stably changed, there is no problem in displaying the OSD.

Therefore, the pulse driver does not need to apply a high voltage of 300V or more, as in the case of a video display, to the voltage level of the signal applied during the reset period, and low enough to stabilize the arrangement of priming particles and wall charges in the discharge cell. Only voltage may be applied.

The pulse driver may reduce the number of sustain pulses S applied to not only a cell on which the OSD is displayed but also to at least one cell on which the OSD is not displayed.

In general, the afterimage problem is not so serious when the OSD is displayed at the same time the video is displayed. However, when the still image is displayed and the OSD is displayed for a few seconds or more, an afterimage occurs in an area where the OSD is displayed.

In particular, the afterimage problem becomes more serious when the area where the OSD is not displayed is black or white. In this case, the afterimage may be improved by allowing the number of sustain pulses S to be applied to the cell in which the OSD is not displayed, to be equal to or smaller than the cell in which the OSD is displayed.

Looking at the driving method of the plasma display device according to the present invention configured as described above are as follows.

First, for the cell on which the OSD is displayed, the number of reset signals and the maximum voltage level applied during one frame period are varied.

In general, in the case of the cell on which the OSD is displayed, since the same gray level is displayed for several seconds or more, an afterimage occurs due to phosphor degradation. In particular, phosphor degradation is mainly affected by the reset signal and the sustain signal applied during the reset period.

Accordingly, the afterimage may be improved by reducing the number of reset signals applied during one frame period and reducing the magnitude of the maximum voltage level applied during the reset period than when the video is displayed.

At this time, the number of reset signals applied during one frame period is in the range of 1 to 6 to initialize the initial discharge cells of the frame, and does not perform the initialization of the discharge cells for the frame in which the number of sustain discharges increases. Reduce

In particular, even if only the set down signal is applied without applying the setup signal, which is a high voltage signal, it is possible to stabilize the arrangement of the wall charges. Therefore, only the set down signal may be applied without the setup signal.

In addition, since the cells displaying the OSD display the same gray level every frame, even when the reset signal is applied, the initialization of the discharge cells is performed by applying only a low voltage without applying a high voltage setup signal like the cell in which the video is displayed. To perform.

That is, the afterimage is improved by lowering the maximum voltage level applied during the reset period to the cell where the OSD is displayed to be lower than the maximum voltage level applied during the reset period to the cell where the video is displayed.

As described above, if the number of reset signals applied during one frame period is reduced or the voltage level of the reset signal is lowered, no reset discharge is generated or a weak reset discharge is generated, thereby reducing afterimages.

In general, the plasma display panel determines the number of sustain pulses according to the APL of the input image. When the OSD is displayed, the APL decreases, so that the number of sustain pulses applied during one frame period increases.

When the number of sustain pulses applied during one frame period is increased in this way, the phosphor deterioration due to the sustain discharge is also increased, resulting in further afterimages.

Therefore, in the method of driving the plasma display panel device of the present invention, when the number of sustain pulses according to APL is 500 or more, the number of sustain pulses applied during one frame period is adjusted to be within 200 to 500. It is possible to improve the afterimage by reducing phosphor deterioration due to sustain discharge.

In addition, when the number of sustain pulses according to the APL is 500 or more, the number of reset signals applied during one frame period is reduced by reducing the number of reset signals applied than when the number of sustain pulses according to the APL is 500 or less. In one frame period, one to six reset signals are applied. Even in this case, the afterimage improvement effect is great even if the set down signal is kept and only the number of setup signals is reduced.

In the method of driving the plasma display panel device, the number of sustain pulses applied to one cell is 500 or less even in a cell other than the cell on which the OSD is displayed, and the reset signal and the voltage level of the reset signal are displayed on the OSD. Variable like cells to maximize the afterimage improvement effect.

If a setup signal is applied to only one to six subfields or a setup signal is reduced to a discharge cell without applying a setup signal to every subfield, an afterimage may be improved in an area where the OSD is displayed. Can be.

In addition, even if the brightness of the area where the OSD is displayed by the decrease in the number of sustain pulses is reduced, the black area where the OSD is not displayed due to removing the setup signal or reducing the size of the setup signal is darker. It is possible to secure contrast.

As described above, the plasma display panel device and the driving method thereof according to the present invention have been described with reference to the illustrated drawings. The application is possible by those skilled in the art within the scope.

Plasma display panel device and driving method thereof according to the present invention configured as described above is a setup signal and sustain discharge applied to the discharge cell than the case where the video is displayed in the black area around the OSD in the screen on which the OSD is displayed By reducing the number of times, the degradation of the phosphor is prevented to reduce the afterimage and increase the contrast ratio between the OSD and the black area.

Claims (22)

And a pulse driver for varying the number and voltage levels of the drive signals and supplying them to the discharge cells during the reset period, the address period, and the sustain period. The pulse driver adjusts the number of setup signals such that the number of setup signals supplied to a cell displaying an OSD (On Screen Display) for one frame is less than the number of setup signals supplied to a cell displaying an image for one frame. Plasma display panel device characterized in that. delete delete The method of claim 1, And the pulse driver is arranged so that a setup signal applied to a cell displaying the OSD is within a range of 1 to 6 during one frame period. The method of claim 1, And the pulse driver is arranged so that a set down signal applied to a cell displaying the OSD is within a range of 1 to 6 during one frame period. The method of claim 1, And the maximum voltage level of the setup signal applied to the cell on which the OSD is displayed is lower than the maximum voltage level of the setup signal applied to the cell on which the image is displayed. The method of claim 1, When the pulse driver wants to display A gray for one frame, the plasma display adjusts the number of sustain pulses supplied to the cell on which the OSD is displayed, rather than the number of sustain pulses supplied to the cell on which the image is displayed. Panel unit. The method of claim 7, wherein And the pulse driver is configured so that the number of sustain pulses applied to the cell displaying the OSD during one frame period is 200 or more and 500 or less. The method of claim 1, If the number of sustain pulses applied to the cell displaying the OSD during the one frame period is 500 or more, the pulse driving unit is configured to apply less setup signal than when the number of the sustain pulses is 500 or less Panel unit. And a pulse driver for varying the number and voltage levels of the drive signals and supplying them to the discharge cells during the reset period, the address period, and the sustain period. The pulse driver outputs the number and setup of the setup signals such that the intensity of the setup discharge occurring during the reset period in the cell on which the OSD (On Screen Display) is displayed for one frame is weaker than the setup discharge occurring during the reset period in the cell where the video is displayed. And adjusting a maximum voltage level of the signal. The method of claim 10, The pulse driver adjusts the maximum voltage level of the setup signal supplied to the cell on which the OSD is displayed during the reset period only when the number of sustain pulses applied to the cell displaying the OSD during one frame period is 500 or more. Plasma display panel device. delete In the mode where the OSD is displayed and the mode where the video signal is displayed, the driving signal supplied for one frame is different. Determining the number of sustain pulses according to the gray level value of the OSD to be displayed during the one frame; Adjusting the number of times of applying the setup signal or the set-down signal or the maximum voltage level supplied to the cell on which the OSD is displayed during one frame when the number of the sustain pulses is equal to or greater than a predetermined reference value. Way. The method of claim 13, When the number of sustain pulses is greater than or equal to a predetermined reference value, the number of setup signals supplied to the cell on which the OSD is displayed during one frame is adjusted to be smaller than the number of setup signals applied to the cell on which the image is displayed. Driving method. The method of claim 13, And when the number of sustain pulses is equal to or greater than a predetermined reference value, the number of setup signals supplied to the cell on which the OSD is displayed during one frame is adjusted to be within 1 to 6 values. The method of claim 13, If the number of sustain pulses is equal to or greater than a predetermined reference value, the maximum voltage level of the signal supplied to the cell on which the OSD is displayed during the reset period is adjusted to be lower than the maximum voltage level of the signal applied to the cell on which the image is displayed. Method of driving the device. The method of claim 13, When the number of sustain pulses is greater than or equal to a predetermined reference value, the number of sustain pulses supplied to the cell on which the OSD is displayed during one frame is adjusted to be less than the number of sustain pulses applied to the cell on which the image is displayed. Way. The method of claim 13, And when the number of sustain pulses is equal to or greater than a predetermined reference value, the number of sustain pulses supplied to the cell on which the OSD is displayed during one frame is adjusted to be within 200 to 500. delete The method of claim 13, If the number of sustain pulses applied during the one frame period is 500 or more, the plasma display is characterized in that the setup signal applied to the cell on which the OSD is displayed during one frame period is within 1 to 6 ranges. Method of driving a panel device. The method of claim 13, When the number of sustain pulses applied during the one frame period is 500 or more, the maximum voltage level applied to the cell on which the OSD is displayed during the reset period is higher than when the number of sustain pulses applied during the one frame period is 500 or less. And driving the plasma display device. delete

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