KR100551041B1 - Driving method of plasma display panel and plasma display device - Google Patents

Abstract

In the driving method of the plasma display panel according to the present invention, the voltage difference between the first electrode and the second electrode is changed from the first voltage to the second voltage in the sustain period of the first subfield in which gray levels are displayed with less than one sustain discharge pulse. Gradually increase until. This makes it possible to express grayscales more precisely than to implement the first subfield with one sustain discharge pulse and to ensure grayscale linearity.

PDP, electrode, low gradation, unit light, discharge, sustain discharge pulse

Description

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

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

2 is a driving waveform diagram of a plasma display panel according to a first exemplary embodiment of the present invention.

3 is a diagram illustrating the number of sustain discharge pulses for each subfield according to an exemplary embodiment of the present invention.

4 is a driving waveform diagram of a plasma display panel according to a second exemplary embodiment of the present invention.

The present invention relates to a method for driving a plasma display panel (PDP).

A plasma display panel is a flat display device that displays characters or images by using plasma generated by gas discharge, and tens to millions or more of pixels are arranged in a matrix form according to their size.

In the plasma display panel, scan electrodes and sustain electrodes parallel to each other are formed on one surface thereof, and address electrodes are formed on the other surface in a direction orthogonal to these electrodes. The sustain electrode is formed corresponding to each scan electrode, and one end thereof is connected in common to each other.

According to the driving method of the plasma display panel, one frame is driven by being divided into a plurality of subfields, and a gray level is expressed by the combination of each subfield. Each subfield includes a reset period, an address period, and a sustain period.

The reset period serves to erase the wall charges formed by the previous sustain discharge and to set up the wall charges in order to stably perform the next address discharge. The address period is a period in which a wall charge is accumulated in a cell (addressed cell) that is turned on by selecting a cell that is turned on and a cell that is not turned on in the panel. The sustain period is a period in which sustain discharge is performed to actually display an image in the addressed cell.

In order to implement a high efficiency plasma display panel, the ratio of xenon (Xe) in the discharge gas is increased to increase luminous efficiency and luminance. As such, when the ratio of xenon is increased to drive the plasma display panel, the size of unit light generated by sustain discharge is increased, thereby lowering the low gradation power. Therefore, in the plasma display panel using High Xe, a lower minimum unit light is required in order to maximize the low gray scale expression power.

The minimum unit light is expressed as the sum of the light generated by the reset discharge in the reset period, the light generated by the address discharge in the address period, and the light generated by one sustain discharge in the sustain period. At this time, since the reset discharge in the reset period is weak and the light generated by the reset discharge is almost ignored, the minimum unit light can be represented by the light by the address discharge and the light by the sustain discharge. However, as described above, due to the use of High Xe for the high efficiency plasma display panel, a large amount of light is generated by the address discharge and the one sustain discharge, thereby degrading the low gray scale.

In addition, the plasma display panel calculates an Automatic Power Control (APC) level according to the detected load ratio of the image data input from the outside, and calculates the total number of sustain discharge pulses corresponding to the calculated APC level. At this time, when there is a large display load displaying one frame, the total number of sustain discharge pulses in one frame is reduced according to the APC (Automatic Power Control) level so as not to exceed a certain power consumption. As a result of applying the APC, less than one sustain discharge pulse is required.

In other words, if the total number of sustain discharge pulses is proportionally assigned to the weight of each subfield, the number of sustain discharge pulses of each subfield is determined. A case where a sustain discharge pulse is assigned is generated. In this case, if this subfield is implemented with one sustain discharge pulse, the light is too counted. Therefore, a method for implementing less than one sustain discharge pulse is needed.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a plasma display panel driving method and a plasma display device capable of implementing less than one sustain discharge pulse.

According to an aspect of the present invention, a frame is formed in a plasma display panel including a plurality of first electrodes, a plurality of second electrodes, and a plurality of third electrodes formed in a direction crossing the first electrode and the second electrode. A method of driving by dividing into a plurality of subfields is provided. The driving method includes selecting a discharge cell to be turned on in an address period in a first subfield in which gray levels are indicated by less than one sustain discharge pulse among the plurality of subfields, and in the sustain period, the first electrode and the Gradually increasing the voltage difference of the second electrode from the first voltage to the second voltage.

And in the sustain period of the remaining subfields other than the first subfield, alternately applying a sustain discharge pulse having the second voltage to the first electrode and the second electrode. In this case, one sustain discharge pulse may be applied in the sustain period of the second subfield having a weight greater than the weight of the first subfield and smaller than the weight of the other subfield.

In the reset period of the second subfield subsequent to the first subfield, the method may include gradually decreasing the voltage to the third voltage while the second voltage is applied to the first electrode.

According to another feature of the present invention, a plasma display panel in which discharge cells are formed between a first electrode, a second electrode, and a third electrode, and a driver for applying a driving voltage to the first electrode, the second electrode, and the third electrode. And a control unit for dividing and driving one field into a plurality of subfields, generating a control signal for driving the first and second electrodes and a control signal for driving the third electrode, and transmitting the control signal to the driving unit. A plasma display device is provided. In this display device, the control unit calculates the number of sustain discharge pulses in each subfield by dividing the total number of sustain discharge pulses determined according to the load ratio of the input video signal by the ratio of the weights of the respective subfields. In the sustain period of the subfield in which the number of sustain discharge pulses of the plurality of subfields is calculated by the controller to be less than one, the voltage difference between the first electrode and the second electrode is gradually increased from the first voltage to the second voltage. Let's do it.

The driving unit may increase the voltage difference between the first electrode and the second electrode to the second voltage and then maintain the second voltage.

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

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

First, the plasma display device 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 driver 300, a sustain electrode driver 400, and a scan electrode driver 500. Include.

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

The controller 200 receives an image signal from the outside and outputs an address driving control signal, a sustain electrode X driving control signal, and a scan electrode Y driving control signal. The controller 200 divides and drives one frame into a plurality of subfields having respective weights. In addition, the controller 200 detects a load ratio of the image signal input from the outside and calculates the total number of sustain discharge pulses corresponding to the APC level calculated according to the detected load ratio. The total number of sustain discharge pulses is divided by the ratio of the weights of the respective subfields to determine the number of sustain discharge pulses allocated to each subfield. In this case, when less than one sustain discharge pulse is required in at least one subfield among the plurality of subfields, the controller 200 drives an address to drive the waveform of the first subfield shown in FIG. The control signal, the sustain electrode X drive control signal, and the scan electrode Y drive control signal are output.

The address driver 300 receives an address driving control signal from the controller 200 and applies a display data signal for selecting a discharge cell to be displayed to each address electrode.

The sustain electrode driver 400 receives the sustain electrode X driving control signal from the controller 200 and applies a driving voltage to the sustain electrode X.

The scan electrode driver 500 receives the scan electrode Y driving control signal from the controller 200 and applies a driving voltage to the scan electrode Y.

Next, a driving waveform of the plasma display panel according to an exemplary embodiment of the present invention will be described with reference to FIGS. 2 and 3.

2 is a driving waveform diagram of a plasma display panel according to an exemplary embodiment of the present invention, and FIG. 3 is a diagram illustrating the number of sustain discharge pulses for each subfield according to an exemplary embodiment of the present invention. In FIG. 2, only two subfields of the plurality of subfields are illustrated, and for convenience, the two subfields are illustrated as first and second subfields, respectively. At this time, it is shown that the reset period of the first subfield consists of a rising period and a falling period, and the reset period of the second subfield consists of a falling period. As described above, the driving waveform shown in the first subfield is applied when less than one sustain discharge pulse is required in at least one of the plurality of subfields as shown in FIG. 3.

As shown in Fig. 2, the first subfield includes a reset period, an address period, and a sustain period, and the reset period includes a rising period and a falling period.

First, in the rising period of the reset period of the first subfield, the scan electrode Y is increased from the voltage Vs to the voltage Vset. Then, weak reset discharge occurs from the scan electrode Y to the address electrode A and the sustain electrode X, respectively.

In the falling period of the reset period of the first subfield, the scan electrode Y is reduced from the voltage Vs to the voltage Vnf. At this time, a reference voltage (assuming 0 V in FIG. 2) is applied to the address electrode A, and the sustain electrode X is biased to the Ve voltage. Then, a weak reset discharge occurs between the scan electrode Y and the sustain electrode X and between the scan electrode Y and the address electrode A while the voltage of the scan electrode Y decreases.

Next, in the address period of the first subfield, a scan pulse having a VscL voltage is sequentially applied to the scan electrode Y to select a discharge cell, and the scan electrode to which the VscL voltage is not applied is biased to the VscH voltage. An address pulse having a Va voltage is applied to an address electrode A passing through a discharge cell to be selected from among a plurality of discharge cells formed by the scan electrode Y to which the VscL voltage is applied, and an address electrode (not selected) A) biases to a reference voltage (0V in FIG. 2). In Fig. 2, the VscL voltage is set at the same level as the Vnf voltage in the reset period. Then, address discharge occurs in the discharge cells formed by the address electrode A to which the Va voltage is applied and the scan electrode Y to which the VscL voltage is applied.

Subsequently, in the sustain period of the first subfield, the voltage of the scan electrode Y is gradually increased from 0V to the Vs voltage. Then, in the discharge cells selected in the address period, when the discharge start voltage between the scan electrode Y and the sustain electrode X exceeds the voltage of the scan electrode Y, the scan electrode Y and the sustain electrode X are increased. Weak maintenance discharge occurs between them. In this case, since the amount of light due to the sustain discharge is reduced, rather than applying the sustain discharge pulse of one Vs voltage to the scan electrode Y, the low gray scale expression power can be improved.

In this manner, when the sustain period of the first subfield ends, the second subfield continues. The reset period of the second subfield is formed only in the falling period, and in the reset period of the second subfield, the Vs voltage is applied to the scan electrode Y in the sustain period of the first subfield. The voltage is gradually reduced to the Vnf voltage.

At this time, when sustain discharge has occurred in the sustain period of the first subfield, negative (-) wall charges are formed on the scan electrode (Y), and positive (+) wall charges are formed on the sustain electrode (X) and the address electrode (A). When the discharge start voltage is exceeded with the wall voltage formed in the cell while the voltage of the scan electrode Y is gradually decreasing, the weak discharge occurs as in the falling period of the reset period of the first subfield. Further, since the final voltage Vnf of the scan electrode Y is equal to the final voltage Vnf of the falling period of the first subfield, the wall charge state of the cell after the falling period of the second subfield is equal to that of the first subfield. It becomes substantially the same as the wall charge state after the end of the falling period.

When no sustain discharge has occurred in the sustain period of the first subfield, no address discharge occurs in the address period, so that the wall charge state of the cell remains in the state after the end of the falling period of the first subfield. Since the wall voltage formed in the cell after the fall period of the first subfield is formed near the discharge start voltage together with the applied voltage, no discharge occurs when the voltage of the scan electrode Y decreases to the Vnf voltage. Therefore, since no discharge occurs in the reset period of the second subfield, the wall charge state set in the reset period of the first subfield is maintained.

In this way, in the subfield having the reset period falling, reset discharge occurs when sustain discharge occurs in the immediately preceding subfield, and reset discharge does not occur when there is no sustain discharge.

Since the address period of the second subfield is the same as that of the first subfield, description thereof is omitted. In the sustain period of the second subfield, a sustain discharge pulse having a Vs voltage is applied to the scan electrode Y. At this time, as shown in FIG. 3, one sustain discharge pulse is applied in the sustain period of the second subfield. Then, when the wall voltage is formed between the scan electrode Y and the sustain electrode X by the address discharge in the address period, the sustain discharge is generated at the scan electrode Y and the sustain electrode X by the wall voltage and the Vs voltage. This happens. At this time, since the discharge magnitude is larger than the discharge magnitude in the sustain period of the first subfield, the light due to the sustain discharge of the second subfield is larger than the light in the sustain period of the first subfield.

The driving waveforms of the reset period and the address period in the remaining subfields are the same as in the second subfield, and the sustain discharge pulse of the voltage Vs is applied to the scan electrode Y in the sustain period according to the number of sustain discharge pulses shown in FIG. The process of applying and applying the sustain discharge pulse of the Vs voltage to the sustain electrode X may be repeated as many times as the weight corresponding to the weight indicated by the corresponding subfield.

As such, according to the first embodiment of the present invention, when there is at least one subfield requiring less than one sustain discharge pulse among a plurality of subfields, the same waveform as in the sustain period of the first subfield is applied. In addition to improving the gray scale expressive power, detailed gray scale expression is enabled, and gray scale linearity can be secured.

In the first embodiment of the present invention, the voltage of the scan electrode Y is decreased from the voltage Vs to the voltage Vnf in the falling period of the reset period of the second subfield, but the falling start voltage may be set to a voltage less than or equal to the voltage Vs. Hereinafter, such an embodiment will be described in detail with reference to FIG. 4.

4 is a driving waveform diagram of a plasma display panel according to a second exemplary embodiment of the present invention.

As shown in FIG. 4, except that the driving waveform according to the second exemplary embodiment of the present invention reduces the voltage of the scan electrode Y from the voltage lower than the voltage Vs to the voltage Vnf in the reset period of the second subfield. It is the same as the driving waveform according to the first embodiment of the present invention.

In the falling period of the reset period of the second subfield, while the voltage of the scan electrode Y decreases to the voltage Vnf while the voltage Vs is applied to the scan electrode Y, between the sustain electrode X and the scan electrode Y When the discharge start voltage becomes higher than or equal to, discharge occurs. However, since the Vs voltage is lower than the discharge start voltage between the sustain electrode X and the scan electrode Y, and the voltage of the sustain electrode X is biased by the Ve voltage, the start voltage of the falling slope is higher than the Vs voltage. Can be set to a low voltage. As such, when the starting voltage of the falling slope is lower than the Vs voltage, the falling slope becomes gentler, and as the slope becomes gentler, weaker discharge occurs in the cell. In this case, an additional power source may not be used when the start voltage of the falling slope of the scan electrode Y is set to the reference voltage (0V).

For example, when the falling start voltage of the scan electrode Y is 0 V, the difference between the voltage applied to the sustain electrode X and the scan electrode Y and the address electrode from the outside at the time when the scan electrode Y falls Since the difference between the voltage applied to (A) and the scan electrode Y is 0 V and 0 V, respectively, no discharge occurs. Next, when the voltage of the scan electrode Y gradually drops from 0V, a weak discharge may occur and the wall charge may be set when the difference between the wall voltage formed in the cell and the voltage applied from the outside exceeds the discharge start voltage. In the second exemplary embodiment of FIG. 5, the falling start voltage of the scan electrode Y is set to 0 V. The same applies to the falling period of the second subfield, and among the first or second subfields. It may only apply to either.

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

According to the present invention, when there is at least one subfield requiring less than one sustain discharge pulse among a plurality of subfields, a low rising power can be improved by applying a voltage that gradually rises without applying a sustain discharge pulse. In addition to this, detailed gray scale expression is possible, and gray scale linearity can be secured.

Claims (6)

In a plasma display panel including a plurality of first electrodes, a plurality of second electrodes, and a plurality of third electrodes formed in a direction crossing the first electrode and the second electrode, a frame is driven by dividing a frame into a plurality of subfields. In the method, In a first subfield in which gray levels are displayed with less than one sustain discharge pulse among the plurality of subfields, Selecting a discharge cell to be turned on in the address period, and Gradually increasing the voltage difference between the first electrode and the second electrode from the first voltage to the second voltage in the sustain period; Method of driving a plasma display panel comprising a. The method of claim 1, In the sustain period of the remaining subfields except the first subfield, Alternately applying a sustain discharge pulse having the second voltage to the first electrode and the second electrode; Method of driving a plasma display panel comprising a. The method of claim 2, And a sustain discharge pulse is applied in the sustain period of the second subfield having a weight greater than the weight of the first subfield and less than the weight of the other subfield. The method of claim 2, In the reset period of the second subfield subsequent to the first subfield, Gradually decreasing to a third voltage while a second voltage is applied to the first electrode Method of driving a plasma display panel comprising a. A plasma display panel in which discharge cells are formed between the first electrode, the second electrode, and the third electrode; A driving unit applying a driving voltage to the first electrode, the second electrode, and the third electrode; and And a control unit for dividing and driving one field into a plurality of subfields, generating a control signal for driving the first and second electrodes and a control signal for driving the third electrode, and transmitting the control signal to the driving unit. , The controller calculates the number of sustain discharge pulses in each subfield by dividing the total number of sustain discharge pulses determined according to the load ratio of the input image signal by the ratio of the weights of the respective subfields. The driving unit, In the sustain period of the subfield in which the number of sustain discharge pulses of the plurality of subfields is calculated by the controller to be less than one, And gradually increasing a voltage difference between the first electrode and the second electrode from a first voltage to a second voltage. The method of claim 5, The driving unit, And increasing the voltage difference between the first electrode and the second electrode to the second voltage and maintaining the second voltage.

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