KR20060099639A - Plasma display device and driving method thereof - Google Patents

Abstract

According to the driving method of the plasma display device according to the present invention, the number of subfields to which the main reset waveform for initializing all the discharge cells is applied in the first frame in which the ambient temperature of the plasma display panel or the plasma display panel is lower than the first reference temperature. Is set to be larger than the number of subfields to which the main reset waveform is applied in the second frame in which the ambient temperature of the plasma display panel or the plasma display panel is higher than the first reference temperature. In this way, a large amount of discharge priming is formed by the main reset waveform at a low temperature at which the discharge start voltage becomes high, and low discharge is prevented.

PDP, Electrode, Temperature, Main Reset, Auxiliary Reset, Low Discharge, Priming

Description

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

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

FIG. 2 is a diagram illustrating an operation of the controller shown in FIG. 1.

3 is a diagram illustrating a method of driving a plasma display device according to an exemplary embodiment of the present invention at a low temperature.

4 illustrates a driving waveform of the plasma display device according to the driving method of FIG. 3.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display device and a driving method thereof, and more particularly, to a plasma display device and a driving method thereof capable of preventing low discharge at a low temperature.

Plasma display devices are flat display devices that display characters or images using plasma generated by gas discharge, and dozens to millions or more of pixels are arranged in a matrix form according to their size.

In the panel of the plasma display device, 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.

In general, a plasma display device is driven by dividing a frame into a plurality of subfields having respective weights, and each subfield is composed of a reset period, an address period, and a sustain period when expressed as a temporal operation change. Here, the reset period is a period for initializing the state of each cell in order to perform the addressing operation smoothly in the cell, and the address period is a period during which the wall charges are accumulated in the cells to be turned on to distinguish the discharge cells to be turned on in the panel. to be. The sustain period is a period in which a display operation is performed for a period corresponding to the weight of each subfield for the cell selected in the address period.

As a driving waveform of a conventional plasma display device, according to US Pat. No. 6294875, in order to improve the contrast ratio of a plasma display device, a main reset is performed only in some subfields SF1 of a plurality of subfields and the remaining subfields SF2 to SF8. ) Performs a secondary reset. In this case, the main reset is a reset period for initializing all of the discharge cells, and the auxiliary reset is a reset period for initializing the cells in which sustain discharge has occurred in the immediately preceding subfield.

Since the auxiliary reset performs initialization for the cell in which the sustain discharge has occurred in the immediately preceding subfield, since the discharge priming is sufficiently formed when the cell in which the sustain discharge has occurred in the immediately preceding subfield is selected in the subsequent address period, the address of the subsequent address is reset. Although discharge occurs well, when the cell in which the sustain discharge does not occur in the immediately preceding subfield is selected in a subsequent address period, address discharge does not occur due to lack of discharge priming, and thus low discharge may occur. In particular, the plasma display device has characteristics in which the discharge voltage and discharge characteristics of the panel vary with temperature. In other words, the lower discharge phenomenon becomes more serious because the discharge start voltage is increased when the temperature decreases.

It is an object of the present invention to provide a plasma display device and a driving method thereof capable of preventing low discharge at low temperatures.

According to one aspect of the present invention, there is provided a plasma display device in which one frame is divided into a plurality of subfields and driven. The plasma display device includes a plasma display panel in which a plurality of discharge cells are formed, a main reset waveform for initializing the plurality of discharge cells in each of the subfields, or a discharge cell displaying an image in a previous subfield among the plurality of discharge cells. A driving unit for applying an auxiliary reset waveform to initialize the plurality of discharge cells, a temperature sensing unit sensing an ambient temperature of the plasma display panel or the plasma display panel, and a sensing temperature of the temperature sensing unit is lower than a first reference temperature. And a controller configured to set the number of subfields to which the main reset waveform is applied in one frame is greater than the number of subfields to which the main reset waveform is applied in a second frame in which the sensing temperature is higher than the first reference temperature. do.

According to another aspect of the present invention, there is provided a driving method of a plasma display device for dividing and driving one frame into a plurality of subfields having respective weights. The driving method may include detecting a panel of the plasma display device and an ambient temperature of the panel, comparing the detected temperature with a first reference temperature, and in a first frame in which the detected temperature is lower than a first reference temperature. Setting the number of subfields to which a main reset waveform for initializing all discharge cells is applied to be greater than the number of subfields to which the main reset waveform is applied in a second frame in which the sensing temperature is higher than the first reference temperature. do. In this case, the method may further include setting the number of sustain discharge pulses applied to the discharge cells selected in the first frame to be smaller than the number of sustain discharge pulses in the second frame.

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.

In the present invention, the wall charge refers to a charge formed close to each electrode on the cell wall (eg, the dielectric layer). 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.

Now, a plasma display device and a driving method thereof according to an exemplary embodiment of the present invention will be described in detail.

First, a plasma display device according to an exemplary embodiment of the present invention will be described in detail with reference to FIG. 2. In the following, the main reset is a reset period for initializing all of the discharge cells, and the auxiliary reset is a reset period for initializing the cells in which sustain discharge has occurred in the immediately preceding subfield. That is, the main reset may be defined as a reset period consisting of a rising period and a falling period, and the auxiliary reset may be defined as a reset period consisting only of a falling period.

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 sustain electrode driver 400, a scan electrode driver 500, and It includes a temperature sensor 600.

The plasma display panel 100 includes a plurality of address electrodes A1 to Am extending in the column direction, and a plurality of sustain electrodes X1 to Xn and scan electrodes Y1 to Yn extending in pairs in the row direction. Include. The sustain electrodes X1 to Xn are formed corresponding to the scan electrodes Y1 to Yn, and generally have one end connected to each other in common. The plasma display panel 100 includes a substrate (not shown) on which the sustain and scan 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 arranged to face each other so that the scan 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 sustain and scan electrodes X1 to Xn and Y1 to Yn forms a discharge cell. 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 address electrode driving control signal, a sustain electrode driving control signal, and a scan electrode driving control signal. The controller 200 divides and drives one frame into a plurality of subfields, and each subfield is composed of a reset period, an address period, and a sustain period. In this case, the controller 200 may be configured to reset the main reset to initialize all the discharge cells in the plurality of subfields according to the temperature of the plasma display panel 100 received from the temperature sensing unit 600 and the ambient temperature of the plasma display panel 100. Vary the number Specifically, the controller 200 reduces the number of sustain discharge pulses applied to the sustain electrodes X and the sustain electrodes X in the sustain period in the case of low temperature lower than the normal temperature, and reduces the number of main resets in the plurality of subfields. The control signal is output to the scan electrode and the sustain electrode so that the number is increased.

The address electrode driver 300 receives an address electrode 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 driving control signal from the controller 200 and applies a driving voltage to the sustain electrode.

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

The temperature detector 600 detects an ambient temperature of the plasma display panel 100 or the plasma display panel 100 and transmits the ambient temperature to the controller 200.

Next, an operation of the controller in the plasma display device according to an exemplary embodiment of the present invention will be described in detail with reference to FIG. 2.

FIG. 2 is a diagram illustrating an operation of the controller shown in FIG. 1.

As shown in FIG. 2, the control unit 200 receives the plasma display panel 100 or the ambient temperature of the plasma display panel 100 sensed by the temperature sensing unit 600 and compares the ambient temperature with a preset reference temperature in operation S310. S320).

In this case, when the sensed temperature is smaller than the reference temperature, the controller 200 reduces the number of sustain discharge pulses applied to the sustain electrode X and the sustain electrode X in the sustain period. Then, a period corresponding to the reduced number of sustain discharge pulses is allocated to the reset period, and a control signal for increasing the number of main resets in the plurality of subfields is output to each electrode (S330).

On the other hand, when the detected temperature is greater than the reference temperature, a control signal is output to each electrode so that a general driving waveform is applied (S340). Here, although the general driving waveform is different depending on the characteristics of the plasma display panel 100, for example, the driving waveform may be a waveform in which one or two subfields using the main reset are set in one frame.

For example, assuming that the reference temperature is room temperature (temperature between 15 degrees and 25 degrees), the reference temperature may be 15 degrees. Therefore, when the sensing temperature is lower than 15 degrees, a control signal is output to each electrode to reduce the number of sustain discharge pulses and increase the number of main resets in the plurality of subfields. On the other hand, when the sensing temperature is room temperature of 15 degrees or more, the control signal outputs a general driving waveform to each electrode.

In this case, when the reference temperature is set to one, the control signal for increasing the number of main resets may be a signal for setting the number of subfields using the main reset in one frame to seven, for example.

It is also possible to set a plurality of reference temperatures in addition to one. For example, if the reference temperature is set to three (first to third reference temperature, first reference temperature <second reference temperature <third reference temperature), the sub using the main reset in one frame according to the reference temperature You can also vary the number of fields. That is, if the sensing temperature is less than or equal to the first reference temperature, the number of subfields using the main reset in one frame is set to seven. If the sensing temperature is between the first and second reference temperatures, the main reset is performed in one frame. If the number of subfields to be used is set to five, and if it is between the second reference temperature and the third reference temperature, the number of subfields using the main reset is set to three in one frame, and the sensing temperature is higher than the third reference temperature. If the value is high, the number of subfields using the main reset in one frame may be set to one.

Next, a low temperature driving method of the plasma display device according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 3 and 4.

3 illustrates a driving method of a plasma display device according to an exemplary embodiment of the present invention at a low temperature, and FIG. 4 illustrates a driving waveform of the plasma display device according to the driving method of FIG. 3.

3 and 4, the plasma display device according to an exemplary embodiment of the present invention reduces the number of sustain discharge pulses in the sustain period at a low temperature lower than room temperature and resets the period corresponding to the reduced number of sustain discharge pulses. Increase the number of main resets than at room temperature by assigning to. 3 and 4 illustrate that the main reset is performed in the subfields SF1 to SF7 and the auxiliary reset is performed only in the subfield SF8. In the case of room temperature, the number of subfields using the main reset is 7 Assumed below.

Specifically, in the rising period of the reset period of the subfield SF1, the voltage of the scan electrode Y is gradually increased from the voltage Vs to the voltage Vset while the sustain electrode X is held at 0V. Then, a weak reset discharge occurs from the scan electrode Y to the address electrode A and the sustain electrode X, respectively, and a negative wall charge is formed on the scan electrode Y, and the address electrode A and the A positive wall charge is formed on the sustain electrode X.

In the falling period of the reset period of the subfield SF1, the voltage of the scan electrode Y is gradually decreased from the Vs voltage to the Vnf voltage while the sustain electrode X is maintained at the Ve voltage. Then, while the voltage of the scan electrode Y decreases, 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, and thus the scan electrode ( The negative wall charges formed on Y) and the positive wall charges formed on the sustain electrode X and the address electrode A are erased.

In the address period of the subfield SF1, in order to select the discharge cell, the scan pulses having the VscL voltage are sequentially applied to the scan electrode Y and the address electrode A while the voltage of the sustain electrode X is maintained at the Ve voltage. And an address pulse having a Va voltage. The unselected scan electrode Y is biased to a VscH voltage higher than the VscL voltage, and a reference voltage is applied to the address electrode A of the cell that is not turned on. Then, an address discharge occurs in the discharge cell 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, and a positive wall charge is formed on the scan electrode Y, and the sustain electrode is formed. At (X), a negative wall charge is formed. In addition, a negative wall charge is also formed on the address electrode A. FIG.

Subsequently, in the sustain period of the subfield SF1, the sustain discharge pulse of the Vs voltage is applied to the scan electrode Y and the sustain electrode X in order. Then, discharge occurs in the scan electrode Y and the sustain electrode X by the wall voltage and Vs voltage formed between the scan electrode Y and the sustain electrode X by the address discharge in the address period. Thereafter, the process of applying the sustain discharge pulse of the Vs voltage to the scan electrode Y and the process of applying the sustain discharge pulse of the Vs voltage to the sustain electrode X are repeated the number of times corresponding to the weight indicated by the corresponding subfield. .

In this manner, when the subfield SF1 ends, the subfields SF2 to SF7 are performed in the same operation as the subfield SF1. That is, the number of sustain discharge pulses in the sustain period of each subfield SF2 to SF8 differs depending on the number of times corresponding to the weight indicated by the corresponding subfield. Since the operation is the same as the subfield SF1, the detailed description is omitted.

When the subfield SF7 ends, the subfield SF8 is performed. At this time, since the operation of the address period and the sustain period of the subfield SF8 is the same as the subfield SF1, only the reset period will be described.

The reset period of the subfield SF8 is formed only in the falling period, and in the sustain period of the subfield SF7, the voltage of the scan electrode Y is applied while the sustain discharge pulse of the Vs voltage is applied to the scan electrode Y. Incrementally decreases to Vnf voltage. At this time, when sustain discharge occurs in the sustain period of the subfield SF2, 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. Therefore, if the discharge start voltage is exceeded with the wall voltage formed in the cell while the voltage of the scan electrode Y gradually decreases, weak discharge occurs as in the falling period of the reset period of the subfield SF1. Since the final voltage Vnf of the scan electrode Y is the same as the final voltage Vnf of the falling period of the subfield SF1, the wall charge state of the cell after the falling period of the subfield SF2 ends is determined by the second sub. It becomes substantially the same as the wall charge state after the end of the falling period of the field. 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.

As described above, according to an exemplary embodiment of the present invention, at a low temperature lower than room temperature, the number of sustain discharge pulses is reduced and the number of main resets is increased. In this case, since sufficient discharge priming is formed by the main reset, stable address discharge can be caused to a cell in which sustain discharge has not occurred by a subsequent auxiliary reset even in a low temperature where the discharge voltage becomes high.

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, the discharge priming is sufficiently formed by reducing the number of sustain discharge pulses in each subfield and increasing the number of main resets for initializing all discharge cells in the case of low temperature lower than normal temperature, thereby preventing low discharge.

Claims (7)

In a plasma display device in which one frame is divided into a plurality of subfields and driven, A plasma display panel in which a plurality of discharge cells are formed; A driver for applying a main reset waveform for initializing the plurality of discharge cells in each subfield or an auxiliary reset waveform for initializing a discharge cell displaying an image in a previous subfield among the plurality of discharge cells, to the plurality of discharge cells; A temperature detector configured to detect an ambient temperature of the plasma display panel or the plasma display panel; The main reset waveform in the second frame in which the sensing temperature is higher than the first reference temperature is the number of subfields to which the main reset waveform is applied in the first frame in which the sensing temperature of the temperature sensing unit is lower than the first reference temperature. Control unit setting more than the number of subfields to be applied Plasma display device comprising a. The method of claim 1, The driving unit applies a plurality of sustain discharge pulses alternately having a high voltage and a low voltage to a selected discharge cell, And the control unit sets the number of the sustain discharge pulses in the first frame to be less than the number of the sustain discharge pulses in the second frame. The method according to claim 1 or 2, The controller may be configured to set the number of subfields to which the main reset waveform is applied in the third frame lower than the second reference temperature lower than the first reference temperature, between the first reference temperature and the second reference temperature. And more than the number of subfields to which the main reset waveform is applied. The method of claim 3, The plasma display panel includes a plurality of first electrodes and a second electrode, and a plurality of third electrodes formed in a direction crossing the first electrode and the second electrode. The main reset waveform is a waveform that gradually increases the voltage of the first electrode from the first voltage to the second voltage and then gradually decreases the voltage from the third voltage to the fourth voltage. The auxiliary reset waveform is a waveform that gradually decreases the voltage of the first electrode from a fifth voltage to a sixth voltage. In the driving method of a plasma display device which drives one frame divided into a plurality of subfields having respective weights, Detecting a panel of the plasma display device and an ambient temperature of the panel; Comparing the sensed temperature with a first reference temperature, and The number of subfields to which a main reset waveform for initializing all discharge cells is applied in a first frame in which the sensing temperature is lower than a first reference temperature is applied to the main reset waveform in a second frame in which the sensing temperature is higher than the first reference temperature. Setting more than the number of subfields to be applied Method of driving a plasma display device comprising a. The method of claim 5, Setting the number of sustain discharge pulses applied to the discharge cells selected in the first frame to be less than the number of sustain discharge pulses in the second frame. The driving method of the plasma display device further comprising. The method according to claim 5 or 6, Comparing the sensed temperature with a second reference temperature lower than the first reference temperature, and The number of subfields to which the main reset waveform is applied in a third frame in which the sensing temperature is lower than a second reference temperature is determined in the fourth frame in which the sensing temperature is between the first reference temperature and the second reference temperature. Setting more than the number of subfields to which the waveform is applied The driving method of the plasma display device further comprising.

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