KR20060121018A - Device which controls set-down voltage when it follows in change of temperature of plasma display panel - Google Patents

Abstract

A device for adjusting set-down voltage according to the temperature change of a plasma display panel is provided to secure stable driving of the plasma display panel at low temperature by dividing voltage by resistances and applying the divided set-down voltage to a comparator. A device for adjusting set-down voltage(Vd) according to the temperature change of a plasma display panel includes the plasma display panel having pixel cells, which are formed in each crossing part of first and second sustain electrodes for generating discharge and address electrodes and arranged in a matrix form; a set-down signal generating unit supplying reset-down pulse to the first sustain electrode in a set-down of a reset period; a set-down voltage comparing and detecting unit(320) detecting the voltage of reset-down pulse from the set-down signal generating unit, comparing the voltage of reset-down pulse with pre-set reference voltage(Vr), and then applying a scan driving control signal; and a scan driving unit executing address discharge in response to a scan driving control signal output from the set-down voltage comparing and detecting unit. The set-down voltage comparing and detecting unit comprises a variable resistance(321) receiving a bit control signal of a temperature sensor and variably adding and subtracting resistance components, and a comparator(324) comparing the set-down voltage, which is divided by the variable resistance according to the temperature change and higher than negative-polarity scan voltage by a predetermined voltage level, with the pre-set reference voltage for performing addressing by the scan driving unit.

Description

DEVICE WHICH CONTROLS SET-DOWN VOLTAGE WHEN IT FOLLOWS IN CHANGE OF TEMPERATURE OF PLASMA DISPLAY PANEL}

1 illustrates a driving waveform of a scan electrode Y among voltages for driving a conventional plasma display panel.

2 is a view illustrating a driving waveform of the scan electrode Y to be changed by a temperature change among voltages for driving the plasma display panel according to the present invention.

3 is a circuit diagram of a set-down voltage comparison detection unit of a plasma display panel according to the present invention.

The present invention relates to an apparatus, and more particularly, to an apparatus for stably driving a plasma display panel by changing a set-down voltage according to a temperature change of the plasma display panel.

FIG. 1 illustrates a driving waveform of a scan electrode Y among voltages for driving a conventional plasma display panel.

As shown, the driving waveform of the scan electrode is a reset period for initializing the full screen of the plasma display panel, an address period for selecting a cell, and a sustain for maintaining the discharge of the selected cell. It is driven by periods.

The AC plasma display panel driving waveform is basically expressed as a "RESET" section for making the same condition before address discharge and a "SCAN" section for addressing image data to the selected scan line.

The reset section initializes all the cells of the plasma display panel.

Initialization means to make all the wall charges generated in the previous discharge for the ON cell or the OFF cells in the same condition so that the subsequent discharge can proceed normally.

Since all cells are affected by the discharge in this section, light generation should be suppressed as much as possible in order to improve contrast.

In order to suppress light generation in the reset section, the most widely used method in the AC plasma display panel is a dark discharge reset using a voltage ramp.

The reset section is composed of a "set-up" section and a "set-down" section.

In the set-up period, a voltage lamp was applied to the Y electrode and the X electrode and the Z electrode were kept at 0V.

In the set-down period, down-ramp is applied to the Y electrode, Vs is applied to the Z electrode, and 0V is applied to the X electrode.

At the end of the set-down ramp, when the 0V to the X electrode, the Vs to the Z electrode, and the -Vy + ΔVy to the Y electrode were applied, the gap voltage between the YZ and XY electrodes was near the discharge start voltage. In addition, strong normal glow discharge can occur when a change in external voltage occurs in the direction of increasing the discharge space voltage from these voltages.

When ΔVy = 0, the voltage of the scan pulse is the same as the last voltage of the set-down ramp, so the X-Y discharge space voltage is near the discharge start voltage only by the scan pulse alone.

In case of? Vy> 0, the X-Y discharge space voltage due to the scan pulse alone is in the transition region where dark discharge and glow discharge can be generated, thereby further reducing Vd.

If DELTA Vy is too large, misdischarge may occur between the X-Y and Y-Z electrodes only by the scan pulse alone.

Therefore, in the optimized waveform, DELTA Vy is set so as to be located in the middle region of the discharge between X-Y electrodes without generating an erroneous discharge between Y and Z.

The voltage setting of the scan section is a major factor influencing the high and low temperature characteristics of the plasma display panel.

In the reset period, a rising ramp waveform Ramp-up is simultaneously applied to all scan electrodes in the set-up period.

This rising ramp waveform causes discharge to occur in the cells of the full screen.

By this setup discharge, positive wall charges are accumulated on the address electrode and the common sustain electrode, and negative wall charges are accumulated on the scan electrode.

In the set-down period, after the rising ramp waveform is supplied, the falling ramp waveform Ramp-down falling at the positive voltage lower than the peak voltage of the rising ramp waveform is simultaneously applied to the scan electrodes.

The falling ramp waveform causes some of the overcharged wall charges by causing a slight erase discharge in the cells.

By this set-down discharge, the wall charges enough to cause the address discharge to stably remain in the cells uniformly.

In the address period, negative scan pulses are sequentially applied to the scan electrodes, and at the same time, positive data pulses are applied to the address electrodes in synchronization with the scan pulses.

As the voltage difference between the scan pulse and the data pulse and the wall voltage generated in the initialization period are added, an address discharge is generated in the cell to which the data pulse is applied.

In the cells selected by the address discharge, wall charges are formed such that a discharge can occur when a sustain voltage is applied.

The common sustain electrode is supplied with a positive DC voltage during the set-down period and the address period.

This DC voltage causes set-down discharge between the common sustain electrode and the scan electrode in the set-down period, and address discharge generated between the scan electrode and the address electrode in the address period causes surface discharge between the scan electrode and the common sustain electrode. To transition to.

In the sustain period, sustain pulses sus are alternately applied to the scan electrodes and the common sustain electrodes.

In the cell selected by the address discharge, the sustain voltage, that is, the display discharge, is generated between the scan electrode and the common sustain electrode every time the sustain pulse is applied as the wall voltage and the sustain pulse in the cell are added.

Finally, after the sustain discharge is completed, a ramp waveform (erase) having a small pulse width and a low voltage level is supplied to the common sustain electrode to erase wall charge remaining in the cells of the full screen.

However, the conventional plasma display panel has a problem that driving is unstable, such as discharge does not occur when operating in a low temperature environment.

For example, an address discharge may not occur when scanning a plasma display panel in a low temperature environment.

If no address discharge occurs for the selected cell in this way, an image cannot be displayed because sustain discharge does not occur in the selected cell even if a sustain voltage is applied.

As a result of many experiments and analysis of the experiments, the main cause of miss discharge in low temperature environment is the recombination of space charge and electrons that lost electrons as the motion of space charges in the cell caused by discharge in low temperature environment is slowed. The recombination is difficult and the wall and space charges that contribute to the discharge are lost over time.

SUMMARY OF THE INVENTION An object of the present invention for solving the above problems is to provide an apparatus for changing the set-down voltage according to the temperature change of the plasma display panel that can be stably operated even at low temperatures.

The objects of the present invention are not limited to the above-mentioned objects, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

The apparatus for adjusting the set-down voltage according to the temperature change of the plasma display panel according to the present invention for solving the above problems is a pixel cell formed at the intersection of the first and second sustain electrodes and the address electrode for generating a discharge Display panel arranged in the form of a matrix, a set-down signal generator for supplying a reset-down pulse to a first sustain electrode during the set-down of the reset period, and the reset from the set-down signal generator An address discharge in response to the scan driving control signal from the set-down voltage comparison detection unit detecting a voltage of the down pulse and comparing the preset reference voltage with the scan driving control signal; Set-down voltage according to the temperature change of the plasma display panel by including a scan driver to perform In the control device, the set-down voltage to the variable resistor comparison detecting unit, receiving the bit control signal of the temperature sensor acceleration the resistance component and the variable; The set-down voltage Vd higher than the negative scan voltage (-Vy) by a predetermined voltage (ΔV) and divided by the variable resistor according to the temperature change, and a preset operation for performing an addressing operation by the scan driver. Comparators for comparing the reference voltage (Vr); characterized in that it comprises a.

Here, it is preferable to further include a Zener diode for removing the variation of the reference voltage input to the comparator.

Here, the divided set-down voltage is preferably at least 9 (V) up to 20 (V).

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention, and methods for achieving them will be apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a view illustrating a driving waveform of the scan electrode Y to be changed by a temperature change among voltages for driving the plasma display panel according to the present invention.

As shown, in the reset period of the subfield SF in the selective write method, the scan / sustain electrode lines Y have a reset pulse RP of a ramp-up waveform followed by a reset pulse (-RP) of a ramp-down waveform. Are supplied sequentially.

The reset pulse of the ramp-down (-RP) does not fall to the negative scan reference voltage (-Vy) but rather to the reset-down voltage (Vrd) higher by ΔV than the negative scan reference voltage (-Vy). . Thereby, the positive wall voltage of the address electrode X by ΔV is less extinguished, and this wall charge amount makes it possible to discharge with a lower data voltage in the subsequent address discharge.

After the reset pulse falls to the reset-down voltage Vrd, the addressing operation is performed immediately.

For example, when the reset pulse falls to the reset down voltage Vrd in the normal operation until the reset period, the selective write scan pulse having the scan voltage is applied in the address period to perform the address discharge.

However, if the reset pulse drops to the set-down voltage Vrd earlier than the end of the reset period due to the external temperature or the driving condition, the conventional art does not maintain the reset-down voltage Vrd during the reset period, but at that time. The address discharge is performed by applying a selective write scan pulse having a scan voltage.

The scan voltage of the scanning pulse applied at this time is a voltage from + Vy to -Vy.

3 is a circuit diagram of a set-down voltage comparison detection unit of a plasma display panel according to the present invention.

As shown, the set-down voltage comparison detector 320 includes a variable resistor 321, a fixed resistor 322, a zener diode 323, and a comparator 324.

The variable resistor 321 receives the bit control signal of the temperature sensor and variably adds or decreases the resistance component, and the variable resistor 321 and the fixed resistor 322 divide voltages, and the zener diode 323 V minimizes the variation of the reference voltage, and the comparator 324 compares the two voltages to output high / low (HIGH / LOW).

The external voltage source Vcc that can be used for the comparator 324 is about 15V, and can be connected to the ground terminal as a negative scan voltage source (-Vy).

Here, the external voltage source Vcc is a voltage that is already designed for driving the gate of the switch element in the plasma display panel, and thus can be easily used.

The set-down voltage Vd and the reference voltage Vr to be detected are compared by the comparator 324.

However, the set-down voltage Vd is not directly applied to the comparator 324 because the set-down voltage Vd is directly applied to the plasma display panel because a reset-peak voltage and a sustain voltage of several hundred volts are applied. .

Therefore, the voltage is divided using the resistors 321 and 322, and the divided set-down voltage Vd is applied to the comparator.

Here, in using the resistors 321 and 322 for voltage dividing, it is possible to change the resistance value according to the temperature of the plasma display panel using a digital resistor that can be controlled digitally.

That is, the divided voltage is changed by the variable resistor 321 according to the temperature, and the reset-down voltage Vrd is set as the reference voltage Vr regardless of the temperature, and compared in the comparator 324. As a result, the actual reset-down voltage Vrd is changed.

In this manner, the set-down voltage Vd input to the comparator 324 has an operating range of 9 (V) <Vd <20 (V), and is compared by the reference voltage Vr.

The signal output through the comparator 324 is changed from low or high to high or low, and then the addressing operation is performed by the scan driver.

As described above, when the reset pulse drops to the reset-down voltage Vrd higher than ΔV higher than the negative scan voltage −Vy by the set-down voltage comparison detector 320, the addressing operation is performed immediately.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical configuration of the present invention described above may be modified in other specific forms by those skilled in the art to which the present invention pertains without changing its technical spirit or essential features. It will be appreciated that it may be practiced. Therefore, the exemplary embodiments described above are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the following claims rather than the detailed description, and the meaning and scope of the claims are as follows. And all changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

According to the configuration of the present invention described above, it is possible to manufacture a device for changing the set-down voltage that the plasma display panel can operate stably even at low temperatures.

Claims (3)

A plasma display panel in which pixel cells formed at intersections of the first and second sustain electrodes and the address electrode for generating a discharge are arranged in a matrix form, and a reset-down pulse on the first sustain electrode when the reset period is set-down; A set-down signal generator for supplying a signal and a set-down voltage comparison detector for detecting a voltage of the reset-down pulse from the set-down signal generator and applying a scan driving control signal to a preset reference voltage; And a scan driver configured to perform an address discharge in response to the scan driving control signal from the set-down voltage comparison detector, wherein the set-down voltage according to the temperature change of the plasma display panel is adjusted. The set-down voltage comparison detection unit, A variable resistor that receives the bit control signal of the temperature sensor and variably adds or decreases a resistance component; A predetermined set-down voltage (Vd) higher than the negative scan voltage (-Vy) by a predetermined voltage (ΔV) and divided by the variable resistor according to a temperature change, and a preset operation for performing an addressing operation by the scan driver. Comparator for comparing the reference voltage (Vr) Apparatus for adjusting the set-down voltage according to the temperature change of the plasma display panel comprising a. The method of claim 1, The set-down voltage comparison detection unit further comprises a Zener diode (Zener Diode) for removing a change in the reference voltage input to the apparatus for adjusting the set-down voltage according to the temperature change of the plasma display panel. The method of claim 1, And the divided set-down voltage ranges from a minimum of 9 (V) to a maximum of 20 (V).

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