KR100764665B1 - Plasma display device and driving method - Google Patents

Abstract

A plasma display apparatus and a driving method thereof are provided to increase a voltage of sustain electrodes by maintaining a floating state of the sustain electrodes during a set down interval based on a set down signal. A plasma display apparatus includes scan and sustain drivers(13,14). The scan driver supplies a driving signal to scan electrodes during reset, which has set-up and set-down periods, address, and sustain periods, and supplies set-down signals having different falling end times based on temperature conditions during the set-down period. The sustain driver supplies a driving signal to sustain electrodes during the reset, address, and sustain periods. The sustain driver includes a first switch(Q22) for connecting a ground and a second switch(Q11) for applying a positive polarity bias voltage(Vzb). After starting the set-down period, the first and second switches are turned off so as to maintain a floating state of the sustain electrodes.

Description

Plasma display device and driving method

1 is a driving waveform diagram of a conventional plasma display panel;

2 is a structural diagram of a plasma display panel of the present invention;

3 is a layout view of a driving unit for driving a panel of the present invention;

4 is a partial configuration diagram of the scan driver of the present invention;

5 is a partial configuration diagram of a sustain drive unit of the present invention;

6 is a driving waveform diagram of a plasma display panel according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display device, and more particularly, to control floating during a portion of the setdown period such that the application time of the sustain bias voltage is varied in response to the falling end level of the setdown signal applied during the reset period varying with temperature. The present invention relates to a plasma display device and a driving method thereof.

In the plasma display device, a discharge cell is formed between a rear substrate on which a partition wall is formed and a front substrate opposite thereto, and an image of a vacuum ultraviolet light generated when an inert gas inside each discharge cell is discharged by a high frequency voltage emits a phosphor. The waveform of the conventional driving signal applied to the scan electrode and the sustain electrode formed on the front substrate will be described with reference to FIG. 1 as follows.

The plasma display panel expresses grayscale by dividing one frame into a plurality of subfields, and each subfield SF includes a reset period RP for initializing charge in the discharge cell and an address period AP for selecting the discharge cell. ) And a sustain period SP for displaying an image, and the reset period RP is further divided into a setup period SU and a set down period SD.

In this case, a signal supplied to the scan electrode Y during the setup period SU is called a setup signal, and a signal supplied during the set down period SD is called a set down signal. As a result, there is a problem that the speed of descending changes.

If the panel is operated at normal temperature, the setdown signal is lowered as in ① of FIG. 1, but when the panel is operated at a high temperature of more than 50 degrees, the setdown signal is lowered as in ② as the descending speed is decreased. Will be pulled. It is analyzed that the change of the setdown signal in the high temperature environment is caused by the change of the wall charge loss amount and the operating condition in the discharge cell.

That is, in a normal temperature environment, a setdown signal falling down to the first voltage (-Vb1 = -Vy + ΔVy1) is supplied as in ①, whereas in a high temperature environment, as the falling speed is smaller as in ②, The voltage drops to two voltages (-Vb2 = -Vy + ΔVy2).

Thereafter, the scan electrode Y is raised to the scan bias voltage Vyb, and the sustain electrode Z is raised to the sustain bias voltage Vzb.

On the other hand, the time when the voltage of the sustain electrode (Z) is raised to the sustain bias voltage (Vzb) is set to be synchronized with the time when the voltage of the scan electrode (Y) in the normal temperature environment, bar temperature When the setdown signal is first lowered as shown in ②, there is a problem that the voltage level of the sustain electrode Z does not increase until a predetermined time T has elapsed.

That is, in the high temperature environment, the falling completion point of the set-down signal is advanced, so that the voltage of the scan electrode Y is increased at the time of ②, and is increased at the time of ① as set in the sustain electrode Z, so that synchronization is not performed. Undesirable discharge may occur due to the voltage difference between the scan electrode and the sustain electrode for a predetermined time T, resulting in a problem of deterioration in image quality.

The present invention has been made to solve the above-mentioned problems of the prior art, and when the voltage level at which the set-down signal is lowered is changed according to the temperature in the environment in which the plasma display panel is driven, the corresponding sustain electrode is used as a positive electrode. It is an object of the present invention to provide a plasma display device having a sustain driver that performs floating during a set down period so that a timing of applying a sustain bias voltage is synchronized.

The plasma display device of the present invention for solving the above problems is a scan driver for supplying a drive signal to the scan electrode during the reset period, the address period and the sustain period consisting of a setup period and a set-down period; A sustain driver for supplying a drive signal to the sustain electrode during the reset period, the address period, and the sustain period, the sustain driver including a first switch connected to ground and a second switch for applying a positive sustain bias voltage; Turn off the first and second switches so that the sustain electrode remains floating during the set down period.

In this case, the period in which the first and second switches are turned off by the sustain driver is the remaining period except the initial 5% of the set-down period.

The scan driver supplies a set down signal that gradually descends for erase discharge in a discharge cell to the scan electrode during the set down period, and a time point at which the set down signal is completed to fall varies with temperature. In addition, the scan electrode is raised to the scan bias voltage level immediately after the set down signal is completed.

The sustain driver causes the second switch to conduct so that the sustain electrode rises to the sustain bias voltage level at the same time as the address period starts.

That is, at the time when the setdown signal supplied to the scan electrode is lowered to the scan bias voltage during the setdown period, the voltage level of the sustain electrode, which is in the floating state, is first increased with the increase of the voltage of the scan electrode. At the beginning of the address period, the voltage level of the sustain electrode rises secondary.

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

2 is a view for explaining the structure of the panel (P) of the present invention, the panel is formed by combining the front substrate (A) and the back substrate (B).

The scan electrode 1 and the sustain electrode 2 are formed on the front substrate A, the address electrode 6 is formed on the back substrate B, and the scan electrode, the sustain electrode and the address electrode 6 are formed in the cell. Is crossed in.

The scan electrode 1 and the sustain electrode 2 are composed of transparent electrodes 1b and 2b and bus electrodes 1a and 2a, respectively, and the transparent electrode is oxidized with a trace amount of tin oxide called indium tin oxide (ITO). Indium is made of high transmittance so that the light generated inside the cell is emitted to the outside. In addition, bus electrodes 1a and 2a are provided to lower the sheet resistance of the transparent electrode.

The dielectric layer 3 is formed on the scan electrode 1 and the sustain electrode 2, and the protective film 4 for protecting the dielectric layer 3 can also be formed.

A dielectric layer 8 is also formed on the address electrode 6, and on the dielectric layer, barrier ribs 7 for partitioning the discharge cells in the horizontal and vertical directions, and R, G coated on the dielectric layer 8 and the barrier ribs 7. , B phosphor 9 is formed.

In this case, the plasma display panel according to the present invention is not limited to FIG. 2.

For example, the scan electrode 1 and the sustain electrode 2 may each have an ITO-less structure including only the bus electrodes 1a and 2a, not including the transparent electrodes 1b and 2b made of ITO, respectively. Although not yet, it may be an integral BM structure in which the black matrix BM is integrally formed on the front substrate A.

In addition, the scan electrode 1 and the sustain electrode 2 may each include two or more electrode lines, and may further include other electrodes.

In addition, the structure of the barrier rib formed on the back substrate B is shown in FIG. 2, but it is a close type (close type), which is a structure in which the discharge cells are closed. Stripe Type), or may be a fishbone type having a protrusion formed on the vertical partition wall 7 at a predetermined distance.

3 is a diagram illustrating a data driver 12, a scan driver 13, and a sustain driver 14 for applying a drive signal to an electrode formed on the panel P. Referring to FIG.

Referring to FIG. 3, a data driver 12 for supplying data to address electrodes X1 to Xm formed in a panel, a scan driver 13 for driving scan electrodes Y1 to Yn, and a sustain electrode A sustain driver 14 for driving (Z) and a timing controller 11 for controlling switch timing in each driver 12, 13, 14 are provided.

The data driver 12 supplies data pulses for on-cell and off-cell selection to the address electrodes X1 to Xm.

3 illustrates a structure in which the address electrodes X1 to Xm are non-divided to be driven in a single scan method, but the present invention is not limited thereto. The address electrodes of the present invention may be divided into two or more divided address electrode groups, and It is specified that a dual scan method in which a driving signal is applied to the first scan electrode lines Y1 to Ym and the second scan electrode lines Yn-m to Yn that cross each other is also possible.

Further, the address electrodes X1 to Xm are divided into odd-numbered address electrodes X1, X3, ..., Xm-1 and even-numbered address electrodes X2, X4, ..., Xm. Therefore, a structure including two or more data drivers for applying a drive signal is also possible.

The scan driver 13 supplies a gradually rising set-up signal and a gradually falling set-down signal in the reset period under the control of the timing controller 11, and selects a scan line to which data is supplied in the address period AP. The scan pulses are sequentially supplied to the scan electrodes Y1 to Yn, and then a sustain pulse is supplied during the sustain period SP to maintain the discharge in the selected on cells.

The sustain driver 14 alternately operates with the scan driver 13 during the sustain period SP to supply a sustain pulse to the sustain electrode.

In addition, the timing controller 11 receives the vertical / horizontal synchronization signal and the clock signal to generate the timing control signals CTRX, CTRY, and CTRZ required for each of the driving units 12, 13, and 14, and the timing control signals CTRX, Each drive unit is controlled by supplying CTRY and CTRZ to the drive units 12, 13, and 14.

The timing control signal CTRX supplied to the data driver 12 includes a sampling clock for sampling data, a latch control signal, and a switch control signal for controlling on / off time of the driving switch element.

In addition, the timing control signals CTRY and CTRZ applied to the scan driver 13 and the sustain driver 14 include a switch control signal for controlling on / off time of the energy recovery circuit and the driving switch element.

Here, referring to FIG. 4, the configuration of the scan driver 13 for supplying a drive signal to the scan electrodes Y1 to Yn is described below. The scan driver includes a setup signal applying unit (not shown) that applies a setup signal during the reset period RP. And a set down signal applying unit 133 for applying the set down signal, a scan signal applying unit 131 for applying the scan pulse during the address period AP, and a sustain signal applying the sustain pulse during the sustain period SP. It is configured to include a part (not shown).

In this case, the scan signal applying unit 131 shown in FIG. 4 includes a first switch Q1 connected to a scan voltage source for supplying a scan voltage Vsc to increase to a scan bias voltage Vyb, and a scan IC connected to a scan electrode. 132, and a switch Q2 for lowering to a negative third voltage (-Vy) at the scan bias voltage level.

Here, the scan IC 132 is composed of a high switch and a low switch connected in a push-pull form and connected to the scan electrode Y through an output node therebetween, and the scan IC 132 and the second switch Q2. The nodes between the nodes are called first nodes n1.

In addition, the set-down signal applying unit 133 is turned on during the set-down period SD so that the third switch Q3 for supplying a voltage falling down to the third voltage -Vy with a predetermined slope is provided by the first node n1. And a comparator 134 or the like connected to the third voltage (-Vy) to terminate the falling of the set-down signal at the first voltage (-Vb) higher by ΔVy.

In more detail, the first and second voltage divider resistors R1 and R2 connected in parallel with the third switch Q3 are connected about the inverting terminal (-) of the comparator 134 and distribute the reference voltage Vcc. The third and fourth voltage divider resistors R3 and R4 are connected to the non-inverting terminal (+) of the comparator. Accordingly, the comparator 134 causes the set-down signal to fall down at a voltage (-Vb) higher by ΔVy than the third voltage (-Vy), which will be described below in more detail with reference to FIG. 6.

Meanwhile, referring to FIG. 5, the configuration of the sustain driver 14 for supplying a driving signal to the sustain electrode Z includes a switch Q11 for raising the sustain bias voltage Vzb and a drop to the ground level. And a sustain signal applying unit 142 for applying a sustain signal that is raised and lowered complementarily with the scan electrodes during the sustain period SP. In addition, the sustain signal applying unit 142 is connected to the energy recovery unit 141 for recovering and supplying energy from the panel.

Waveforms of the driving signals supplied from the scan driver 13 and the sustain driver 14 shown in FIGS. 4 and 5 will be described in detail with reference to FIG. 6. In particular, the present invention is characterized in that the floating control is performed during the setdown period SD through the switch control of the sustain driver 14 in order to improve the problems caused by the setdown signal that changes with temperature.

First, the reset period R is composed of a setup period SU in which a gradually rising setup signal is applied to the scan electrode and a set down period SD in which a gradually falling setdown signal is applied, and in the setup period SU. A setup signal that gradually rises to a reset voltage is applied to all the scan electrodes Y, and wall charges gradually accumulate therein as a setup discharge is generated by the setup signal.

At this time, the sustain driver 14 conducts the switch Q22 connected to the ground during the setup period SU so that the sustain electrode maintains the ground level.

In addition, in the setdown period SD, a setdown signal that gradually decreases to a voltage (-Vb) higher by ΔVy than the third voltage (-Vy) is applied to the scan electrode, so that excessive wall charges unnecessary for address discharge are discharged in the discharge cell. Erased.

However, as described in the related art, since the set-down signal applied to the scan electrode Y during the set-down period SD is lowered and the completion level of the set-down signal varies depending on the temperature environment, the set-down signal increases to the scan bias voltage Vyb. The timing is also variable. In the present invention, the floating control is performed during the set-down period SD so that the sustain electrode Z is also raised to the sustain bias voltage Vzb in synchronization with the rising time to the scan bias voltage Vyb.

That is, the sustain driver 14 turns off the switch Q22 connected to the ground during the set-down period SD, and simultaneously turns off the switch Q11 connected to the sustain bias voltage source Vzb to float the sustain electrode. Keep it.

As a result, the sustain electrode Z is not changed in voltage level by the driving signal supplied from the sustain driver 14, but is supplied to the charge state inside the discharge cell and the scan electrode Y or the address electrode X facing the discharge cell. The voltage level is changed by the drive signal. The section in which the floating state is maintained will be referred to as a floating section T1.

As described above, the sustain driver 14 according to the present invention performs the floating control during the set-down period SD so that the sustain electrode is maintained along the voltage level of the scan electrode even when the voltage level of the scan electrode rises before the address period AP. The voltage at (Z) is also raised to a predetermined voltage level (Vza).

Thereafter, as the address period AP is started, the switch Q11 for applying the sustain bias voltage Vzb is turned on in the sustain driver 14, whereby the voltage level of the sustain electrode is primarily increased by floating control. The voltage is further increased from Vza to the sustain bias voltage Vzb.

In addition, scan pulses lowering from the scan bias voltage Vyb to the negative voltage −Vy are sequentially applied to the scan electrode Y, and at the same time, a data pulse is applied to the address electrode X, whereby the scan pulse is applied. And the address discharge is generated by the voltage difference of the data pulses, and the discharge cells are selected.

That is, as shown in FIG. 6, the voltage level of the sustain electrode Z does not increase from the ground to the sustain bias voltage level Vzb at once, but is accompanied by a rise in the voltage of the scan electrode Y during the set-down period SD. After the first rise, the second rise as the address period AP starts.

The floating control of the present invention can be selectively applied by sensing the temperature at which the panel is driven. That is, the floating control is not performed in the normal temperature range, and the floating control is performed only when the normal temperature range is exceeded.

Similarly, the floating control of the present invention may be applied in every subfield constituting one frame, and selectively applied in at least one of the subfields.

Referring to the section T1 in which the floating control is performed, the sustain driver 14 performs the floating control before the time when the voltage of the scan electrode Y rises to the scan bias voltage Vyb. 100% of the full span of SD) will be within the interval T1 after the initial 5%. The reason for this is that the time point at which the setdown signal, which changes as ΔVy varies with temperature, is completed, falls within the period T1 after the initial 5% of the setdown period.

More preferably, the floating section T1 may be a section after 50% of the starting point of the set-down period SD. In addition, the floating control may be performed for a period within 5% to 30% based on the end of the set-down period SD.

Since the sustain electrode maintains the floating state during the floating period T1 set as described above, even if the slope of the setdown signal is changed by the temperature environment, no false discharge occurs between the scan electrode and the sustain electrode. As a result, image quality can be improved.

Subsequently, in the sustain period SP, a sustain pulse SUSP is alternately applied such that the voltage difference between the scan electrode Y and the sustain electrode Z becomes the sustain voltage Vs. As a result, a sustain discharge is generated to generate light. Is displayed.

Meanwhile, the driving waveform according to the embodiment of the present invention is not limited to the waveform shown in FIG. 6, but may be variously modified.

For example, the reset period RP may be omitted in at least one subfield of the plurality of subfields constituting one frame, and the reset period RP may exist only in the first subfield.

6, the start voltage of the setup signal and the start voltage of the setdown signal are shown to be substantially the same voltage level, which may be higher than the setdown start voltage level and vice versa. There will be.

On the other hand, the setup signal or the set-down signal is a waveform that gradually rises or falls, which may be raised and lowered stepwise with two or more slopes.

In the at least one subfield of the plurality of subfields constituting one frame, a pre-reset period may exist before the reset period to assist in the formation of sufficient wall charges. For example, while applying a signal in which the voltage value gradually decreases to the scan electrode during the preset period, a reset voltage can be generated in advance by applying a positive voltage to the sustain electrode. However, it is preferable that such a preset period exist only in the first subfield in consideration of the driving margin.

In addition, after the sustain period of one subfield is finished, an erase pulse for uniformizing the wall charge state in the discharge cell may be additionally applied before the reset period of the next subfield is started.

On the other hand, in addition to the waveform shown in FIG. 6 during the sustain period, other signals that may cause sustain discharge may be applied. As a result, the voltage difference between the scan electrode and the sustain electrode needs to exceed the discharge start voltage causing the sustain discharge. The half sustain voltage (-Vs / 2) may be applied, and the positive sustain voltage (Vs) may be applied to only one electrode, and the negative sustain voltage (-Vs) may be sequentially applied to the other electrode. will be.

As described above, those skilled in the art can change the present invention without departing from the technical spirit of the present invention, and the technical scope of the present invention is not limited to the contents described in the detailed description of the specification but is defined by the claims. You will have to lose.

In the plasma display device according to the present invention configured as described above, the sustain electrode is in a floating state for the set down period in response to the voltage level at which the set-down signal is completed to fall and the time at which the fall is completed to vary according to temperature. Even before the start, the voltage of the sustain electrode is increased in synchronization with the completion time of the falling of the setdown signal.

To this end, since the circuit configuration is not changed, the cost is less, and the voltage at the sustain electrode increases with the voltage at the scan electrode, thereby improving the image quality by preventing mis-discharge during a period other than the sustain period. have.

Claims (11)

A scan driver for supplying a driving signal to the scan electrode during a reset period, an address period, and a sustain period comprising a setup period and a setdown period, wherein the setdown period supplies a setdown signal having a different drop completion point according to temperature; And a sustain driver configured to supply a driving signal to the sustain electrode during the reset period, the address period, and the sustain period. The sustain driver includes a first switch connected to the ground and a second switch configured to apply a positive sustain bias voltage. And turning off the first and second switches so that the sustain electrode maintains a floating state after the set down period is started. delete In claim 1, The scan driver supplies a set down signal that gradually descends for erase discharge in a discharge cell during the set down period, to the scan electrode. And supplying a positive voltage such that the scan electrode rises to a scan bias voltage after the set down signal is completed falling. In claim 1, And the sustain driver is configured to conduct the second switch so that the sustain electrode rises to the sustain bias voltage level at the same time as the address period starts. In claim 1, And the sustain driver turns off the first and second switches so that the sustain electrode maintains the floating state for the remaining sections except for the initial 5% section of the set down period. In claim 1, And the sustain driver turns off the first and second switches so that the sustain electrode maintains the floating state for the remaining sections except for the initial 50% section of the set down period. In claim 1, And the sustain driver turns off the first and second switches so that the sustain electrode maintains the floating state for a period of 5% to 30% from the end of the set-down period. A scan driver for supplying a drive signal to the scan electrode during a reset period, an address period and a sustain period comprising a setup period and a setdown period; A sustain driver configured to supply a drive signal to the sustain electrode during the reset period, the address period, and the sustain period; The sustain driver first increases the voltage level of the sustain electrode when the setdown signal supplied to the scan electrode is lowered during the setdown period, and increases the voltage level of the sustain electrode to 2 when the address period starts. A driving method of the plasma display device, characterized in that the elevating step. In claim 8, And the voltage of the scan electrode is increased to a scan bias voltage level immediately after the set down signal is completed. In claim 8, The sustain driver includes a first switch connected to the ground and a second switch configured to apply a positive sustain bias voltage. And turning off the first and second switches for a predetermined period so that the voltage level of the sustain electrode is increased primarily. In claim 10, And the sustain driver is configured to conduct the second switch at a time point at which the address period starts.

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