KR100570659B1 - Driving method of plasma display panel and plasma display device - Google Patents

Abstract

The present invention relates to a method of driving a plasma display panel. In the sustain period of at least one subfield, a voltage slowly rising alternately is applied to the sustain electrode and the scan electrode. At this time, the scan electrode is biased to 0V when a slowly rising voltage is applied to the sustain electrode, and the sustain electrode is biased to 0V when a slowly rising voltage is applied to the scan electrode. As described above, a gentle rising voltage is applied to generate weak discharge in the sustain period, thereby reducing unit light. That is, by reducing the unit light, the low gray scale expressive power may be further increased, and the number of sustain discharges may be further increased in the high efficiency plasma display panel, thereby improving gray scale expressive power.

PDP, retention period, lamp voltage, unit light

Description

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

1 is a schematic partial perspective view of a typical plasma display panel.

2 is an electrode array diagram of a general plasma display panel.

3 is a view showing a waveform of the sustain period and the discharge light according to the driving method of the conventional plasma display panel.

4 is a diagram illustrating waveforms and discharge light applied to a sustain period in the plasma display panel driving method according to an exemplary embodiment of the present invention.

FIG. 5 is a diagram illustrating wall charges formed on the sustain electrode and the scan electrode when the sustain discharge waveform shown in FIG. 4 is applied.

6 is a diagram illustrating a change in wall voltage according to a ramp slope.

FIG. 7 illustrates a method of adjusting the optimized voltage Vs so that sustain discharge occurs continuously.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving method of a plasma display panel (PDP), and more particularly to a driving method of a plasma display panel for reducing unit light for gray scale expression.

Recently, flat display devices such as a liquid crystal display (LCD), a field emission display (FED), and a plasma display panel have been actively developed. Among these flat panel display devices, the plasma display panel has advantages of higher luminance and luminous efficiency and wider viewing angle than other flat panel display devices. Therefore, the plasma display panel is in the spotlight as a display device to replace a conventional cathode ray tube (CRT) in a large display device of 40 inches or more.

A plasma display panel is a flat panel display device that displays characters or images using plasma generated by gas discharge, and tens to millions or more of pixels are arranged in a matrix form according to their size. The plasma display panel is classified into a direct current type and an alternating current type according to a shape of a driving voltage waveform applied and a structure of a discharge cell.

In the DC plasma display panel, the electrode is exposed without the discharge space insulated, so that the current flows in the discharge space while the voltage is applied, and there is a disadvantage in that a resistance for current limitation must be made. On the other hand, in the AC plasma display panel, since the electrode covers the dielectric layer, the current is limited by the formation of a natural capacitance component, and the electrode is protected from the impact of ions during discharge.

1 is a partial perspective view of a general plasma display panel, and FIG. 2 is a diagram showing an arrangement of electrodes of a general plasma display panel.

As shown in FIG. 1, the plasma display panel includes two glass substrates 1 and 6 facing each other apart. On the glass substrate 1, the scan electrode 4 and the sustain electrode 5 are formed in pairs and in parallel, and the scan electrode 4 and the sustain electrode 5 are covered with the dielectric layer 2 and the protective film 3. have. A plurality of address electrodes 8 are formed on the glass substrate 6, and the address electrodes 8 are covered with the insulator layer 7. The address electrode 8 and the partition 9 are formed on the insulator layer 7 between the address electrodes 8. In addition, the phosphor 10 is formed on the surface of the insulator layer 7 and on both sides of the partition wall 9. The glass substrates 1 and 6 are disposed to face each other with the discharge space 11 therebetween so that the scan electrode 4, the address electrode 8, the sustain electrode 5, and the address electrode 8 are orthogonal to each other. The discharge space 11 at the intersection of the address electrode 8 and the paired scan electrode 4 and the sustain electrode 5 forms a discharge cell 12.

As shown in FIG. 2, the electrode of the plasma display panel has a matrix structure of n × m. In the column direction, address electrodes A ₁ -A _m are arranged, and in the row direction, n rows of scan electrodes Y ₁ -Y _n and sustain electrodes X ₁ -X _n are arranged in pairs.

In the method of driving the plasma display panel, each subfield (which explains waveforms in one subfield for convenience) generally consists of a reset period, an address period, a sustain period, and an erase period.

The reset period is a period for initializing the state of each cell in order to perform an addressing operation smoothly on the cell, and the address period (or scan period, write period) is a cell that is turned on by selecting a cell that is turned on and a cell that is not turned on. This is a period during which the wall charges are accumulated in the addressed cells). The sustain period is a period in which discharge for actually displaying an image is performed on the addressed cell, and the erase period is a period in which the wall discharge of the cell is reduced to end the sustain discharge.

Here, the waveform of the sustain period in the conventional plasma display panel driving method will be described.

3 is a view showing a waveform of the sustain period and the discharge light according to the driving method of the conventional plasma display panel.

As shown in Fig. 3, in the sustain period, a sustain discharge pulse voltage is alternately applied to the sustain electrode X and the scan electrode Y in order to discharge the cells addressed in the address period. At this time, strong discharge occurs between the sustain electrode and the scan electrode to generate discharge light, and the gray level is expressed through the discharge light.

At this time, in the case of the plasma display panel, high xenon (High Xe) is used to increase the luminous efficiency. In the case where the luminous efficiency is large, when the sustain discharge pulse waveform shown in FIG. Problems in expressing. In addition, when the unit light increases in the plasma display panel having high efficiency, a small number of sustain discharge pulses should be used for each subfield due to problems such as the lifetime of the plasma display panel due to high brightness and panel heat generation. A problem arises.

SUMMARY OF THE INVENTION The present invention has been made in an effort to solve the above problems of the related art, and to provide a method of driving a plasma display panel which reduces unit light generated in a sustain period.

According to a feature of the present invention for achieving the above object, a plasma display panel including a plurality of first electrodes and second electrodes, and a plurality of third electrodes formed to intersect the first and second electrodes; A method is provided. The driving method includes: (a) applying a first voltage to the first electrode in a sustain period of at least one subfield among a plurality of subfields forming one field; And (b) the second electrode while the first voltage is applied to the first electrode so that the voltage difference applied to the first electrode and the second electrode gradually rises from the first voltage to the second voltage. Applying a voltage. In this case, the at least one subfield is used to express low gradation. In the step (b), the voltage applied to the second electrode is a ramp voltage so that the voltage difference between the first electrode and the second electrode gradually rises.

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According to another feature of the present invention, a plasma display device is provided. The plasma display device includes a first substrate, a plurality of first electrodes and a second electrode formed on the first substrate, and a second substrate facing and spaced apart from the first substrate, and the first and second electrodes. The first electrode, the second electrode and the first electrode to discharge a plurality of third electrodes formed on the second substrate in an intersecting direction and the discharge cells formed by the adjacent first, second and third electrodes; A driving circuit for supplying a driving voltage to the three electrodes, wherein the driving circuit includes a voltage difference applied to the first electrode and the second electrode from a first voltage to a second voltage in a sustain period of at least one subfield; In order to gently rise, a voltage is applied to the second electrode while the first voltage is maintained at the first electrode.

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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.

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

4A illustrates a waveform and discharge light applied to a sustain period in the method of driving a plasma display panel according to an exemplary embodiment of the present invention, and FIG. 4B illustrates an enlarged portion of the waveform applied to the sustain period. It is a figure shown.

Although not shown in FIG. 4, the reset period and the address period are included before the sustain period. One subfield is formed including the reset period, the address period, and the sustain period, and a driving voltage is applied to the scan electrodes Y ₁ -Y _n and the sustain electrodes X ₁ -X _n in each period in the plasma display panel. And an address driving circuit (not shown) for applying a driving voltage to the scan / hold driving circuit (not shown) and the address electrodes A ₁ -A _n . The driving circuit and the plasma display panel are connected to form one plasma display device.

As shown in FIG. 4A, in the sustaining period of the driving method of the plasma display panel according to the exemplary embodiment of the present invention, a ramp gradually rising from 0V to Vs alternately between the sustain electrode X and the scan electrode Y. Apply voltage. At this time, although not shown in Fig. 4A, the 0V voltage is biased to the address electrode. By applying the ramp voltage to the sustain electrode X and the scan electrode Y alternately, weak discharge occurs in the selected cell in the address period.

That is, in the sustain period, a ramp voltage that rises gently to the sustain electrode X while applying 0 V to the scan electrode Y is applied to the scan electrode Y in the sustain electrode X of the cell to be selected in the address period. A weak discharge occurs in Y). Subsequently, in the state where 0 V is continuously maintained at the sustain electrode X, a ramp voltage gradually rising to the scan electrode Y is applied to generate a weak discharge from the scan electrode Y to the sustain electrode X. . By alternately applying the ramp voltage waveform to the scan electrode Y and the sustain electrode X, the amount of light generated in the sustain period becomes smaller than the conventional amount of light.

At this time, when the lamp voltage is applied to the sustain electrode X or the scan electrode Y, as shown in FIG. 4B, the discharge generated between the sustain electrode X and the scan electrode Y may take a certain time. It occurs after this time, and a weak discharge occurs because a ramping ramp voltage is applied. At this time, when the discharge starts to occur, the sum of the voltage applied to the sustain electrode X or the scan electrode Y (after an arbitrary time) and the internal wall voltage exceeds an arbitrary discharge start voltage Vf. A weak discharge is generated by applying to the sustain electrode X or the scan electrode Y a ramp voltage which gradually rises to the voltage Vs at the point where the discharge occurs.

Here, in order to generate sustain discharge continuously and to adjust an appropriate amount of light, the value of voltage Vs should be selected to an appropriate value. FIG. 7 illustrates a method of adjusting the optimized voltage Vs so that sustain discharge occurs continuously.

As shown in FIG. 7, an appropriate Vs applied separately by the difference in the manufacturing conditions of the panel and the characteristics of the panel can be obtained through an experimental method by giving the voltage Vs as variable as ΔVs. At this time, not only the voltage Vs is varied, but also the slope of the lamp voltage or the time for applying the lamp voltage may be determined through the variable DELTA T to determine the slope of generating an appropriate amount of light. Here, an appropriate inclination for generating a weak discharge is required, which will be described below.

6 is a view showing the change of the wall voltage according to the ramp rate (V / usec) Figure 6 is a conventional paper (K. Sakita, K. Taka yama, K. Awamoto, and Y. Hashimoto, " Analysis of a Weak Discharge of Ramp-Wave Driving to Control Wall Voltage and Luminance in AC-PDPs ", in Society for Information Display '00 (SID '00) Digest, pp 110-113). As shown in Fig. 6, it can be seen that the slope of the lamp voltage at which the weak discharge can occur is 7 V / usec or less, and is applied to the sustain electrode X or the scan electrode Y in the sustain period of the present invention. It is preferable to set the slope of the sustain discharge voltage to 7 V / usec or less, i.e., to generate weak discharge in the sustain period through the lamp voltage, it is preferable to set the slope of the lamp to 7 V / usec or less.

FIG. 5 is a diagram showing wall charges formed on the sustain electrode X and the scan electrode Y when the sustain discharge waveform shown in FIG. 4 is applied.

FIG. 5A shows wall charges when the lamp voltage as shown in FIG. 4 is applied to the scan electrode Y. A weak discharge is generated from the scan electrode Y to the sustain electrode X by the application of the lamp voltage. Therefore, negative wall charges are accumulated on the scan electrode Y, and a little positive wall charges are accumulated on the sustain electrode X. Subsequently, when a lamp voltage is applied to the sustain electrode X, a negative wall charge is applied to the sustain electrode X and a positive wall is applied to the scan electrode Y as shown in FIG. A little less charge is formed. FIG. 5C shows wall charge when the lamp voltage is applied to the scan electrode Y again. As a result of the application of the lamp voltage, wall charges are accumulated smaller than before, and weak discharge occurs by applying the lamp voltage, which is an externally applied voltage, to the wall charges again.

Here, the sustain discharge waveform shown in FIG. 4 is a waveform applied in the sustain period of the plurality of subfields forming one frame. In addition, when the efficiency of the plasma display panel is good and the low gradation is low, it is preferable to apply the sustain discharge waveform as shown in FIG. 4 to increase the expressive power of the low gradation.

In FIG. 4, the sustain discharge waveform applied in the sustain period is shown as a ramp waveform. However, the slowly rising RC waveform, the gradually rising stepped waveform, and the slowly rising floating waveform are shown. The weak discharge can be caused in the sustain discharge period as in the embodiment of the present invention through the waveform, the triangular waveform which gradually rises and then decreases.

Thus, the unit light can be reduced by weakly discharging the sustain discharge by alternately applying a waveform gradually rising in the sustain discharge period to the sustain electrode X or the scan electrode Y. In addition, by reducing the unit light, the low gray scale expression may be further increased in the plasma display panel of high efficiency, and the number of sustain discharges mapped for the gray scale representation may be further increased to further improve the gray scale expression. That is, in the high-efficiency plasma display panel, when the unit light is large, the number of sustain discharges should be reduced due to the lifespan and heat generation of the panel. However, when the unit light is reduced as in the present invention, the number of sustain discharges can be increased. Can be improved.

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.

As described above, according to the present invention, by gradually applying a waveform gradually rising in the sustain period to the scan electrode and the sustain electrode, the unit light may be reduced to further increase the low gradation power. In addition, the number of sustain discharges may be further increased in the plasma display panel of high efficiency to further increase gray scale expression power.

Claims (11)

A method of driving a plasma display panel comprising a plurality of first electrodes and a second electrode, and a plurality of third electrodes formed to intersect the first and second electrodes. In the sustain period of at least one subfield among the plurality of subfields forming one field, (a) applying a first voltage to the first electrode; And (b) the voltage at the second electrode while the first voltage is applied to the first electrode so that the voltage difference applied to the first electrode and the second electrode gradually rises from the first voltage to the second voltage. And driving the plasma display panel. The method of claim 1, (c) the first electrode in a state in which the first voltage is applied to the second electrode such that the voltage difference applied to the first electrode and the second electrode gradually rises from the first voltage to the second voltage. And applying a voltage to the plasma display panel. The method according to claim 1 or 2, And the at least one subfield is used to represent low gray levels. The method of claim 1, And the voltage applied to the second electrode so that the voltage difference between the first electrode and the second electrode rises gently in step (b) is a lamp voltage.  The method of claim 4, wherein And the slope of the lamp voltage is 7V / usec or less.  The method of claim 1, And the voltage applied to the second electrode so that the voltage difference between the first electrode and the second electrode rises gently in step (b) is an RC waveform voltage.  The method of claim 2, And the steps (a) to (c) are repeated a predetermined number of times. First substrate, A plurality of first electrodes and second electrodes formed on the first substrate, respectively; A second substrate facing away from the first substrate, A plurality of third electrodes formed on the second substrate in a direction crossing the first and second electrodes, and A driving circuit for supplying a driving voltage to the first electrode, the second electrode, and the third electrode to discharge the discharge cells formed by the adjacent first, second, and third electrodes; The driving circuit may be configured such that, in the sustain period of at least one subfield, the voltage difference applied to the first electrode and the second electrode gradually rises from the first voltage to the second voltage so that the first voltage is applied to the first electrode. The plasma display device applies a voltage to the second electrode while maintaining the voltage. The method of claim 8, And a voltage applied to the second electrode is a lamp voltage. The method according to claim 8 or 9, And the at least one subfield is used to represent low gray scale. The method of claim 9, The slope of the lamp voltage is less than 7V / usec plasma display device.

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