# Patent

## Title
Plasma display panel drive method

## Abstract

Barrier ribs are disposed on a back substrate so as to separate main discharge cells formed of a display electrode pair and a data electrode which face each other and priming discharge cells formed of a clearance between two adjacent scan electrodes. The top parts of the barrier ribs are formed so as to abut on a front substrate. In a driving method, in an odd-numbered line writing time period, scan pulse Va is sequentially applied to odd-numbered scan electrode SCp and voltage Vq is applied to even-numbered scan electrode SCp+1 to cause priming discharge between scan electrode SCp+1 and odd-numbered scan electrode SCp. In an even-numbered line writing time period, scan pulse Va is sequentially applied to even-numbered scan electrode SCp+1 and voltage Vq is applied to odd-numbered scan electrode SCp to cause priming discharge between scan electrode SCp and even-numbered scan electrode SCp+1.

## Background
This Application is a U.S. National phase application of PCT International Application PCT/JP2005/000622.
TECHNICAL FIELD
The present invention relates to a driving method of a plasma display panel used in a wall-mounted television (TV) or a large monitor.
BACKGROUND ART
A plasma display panel (hereinafter referred to as “PDP” or “panel”) is a display device that has a large screen, is thin and light, and has high visibility.
A typical alternating-current surface discharge type panel used as the PDP has many discharge cells between a front plate and a back plate that are faced to each other. The front plate has the following elements:

    
    
        a plurality of pairs of display electrodes disposed in parallel on a front glass substrate; and
        a dielectric layer and a protective layer for covering the display electrodes.

Here, each display electrode is formed of a scan electrode and a sustain electrode. The back plate has the following elements:

        a plurality of data electrodes disposed in parallel on a back glass substrate;
        a dielectric layer for covering the data electrodes;
        a plurality of barrier ribs disposed on the dielectric layer in parallel with the data electrodes; and
        phosphor layers disposed on the surface of the dielectric layer and on side surfaces of the barrier ribs.

The front plate and back plate are faced to each other so that the display electrodes and the data electrodes three-dimensionally intersect, and are sealed. Discharge gas is filled into a discharge space in the sealed product. In the panel having this configuration, ultraviolet rays are emitted by gas discharge in each discharge cell. The ultraviolet rays excite respective phosphors of red (R), green (G), and blue (B), emit light, and thus provide color display.

    
    


A subfield method is generally used as a method of driving the panel. In this method, one field time period is divided into a plurality of subfields, and the subfields at which light is emitted are combined, thereby performing gradation display. Here, each subfield has an initialization time period, a writing time period, and a sustaining time period.
In the initialization time period, initializing discharge is performed simultaneously in all discharge cells, the history of the wall charge for each discharge cell before the initializing discharge is erased, and wall charge required for a subsequent writing operation is formed. Discharge delay is reduced, and priming (detonating agent for discharge=exciting particle) for stably causing writing discharge is generated. In the writing time period, a scan pulse is sequentially applied to the scan electrodes, a writing pulse corresponding to an image signal to be displayed is applied to the data electrodes, writing discharge is selectively caused between the scan electrodes and the data electrodes, and the wall charge is selectively generated. In the subsequent sustaining time period, a predetermined number of sustaining pulses are applied between the scan electrodes and the sustain electrodes, and discharge and light emission are performed selectively in the discharge cells where the wall charge is generated by writing discharge.
For displaying an image correctly, it is important to certainly perform the selective writing discharge in the writing time period. However, the writing discharge has many factors that increase the discharge delay. The factors are, for example, facts that high voltage cannot be used for the writing pulses because of constraints in circuit configuration and that the phosphor layers formed on the data electrodes suppress the discharge. Therefore, the priming for stably causing the writing discharge becomes extremely important.
However, the priming generated by the discharge rapidly decreases with the passage of time. In the driving method of the panel, in the writing discharge after a lapse of a long time since the initializing discharge, the priming generated by the initializing discharge disadvantageously comes short, thereby increasing the discharge delay, destabilizing the writing operation, and reducing the image display quality. When the writing time period is set long for stabilizing the writing operation, disadvantageously, the time taken for the writing time period excessively increases.
For addressing the problems, a panel for generating the priming using a priming discharge cell disposed on the front plate of the panel and reducing the discharge delay, and a driving method of the panel are disclosed (for example, Japanese Patent Unexamined Publication No. 2002-150949).
In this panel, however, adjacent discharge cells are apt to interfere with each other. Especially, in the writing time period, the priming generated by writing discharge of the adjacent discharge cells can cause a writing error or bad writing, and hence the driving voltage margin of a writing operation becomes narrow.
The present invention addresses the problems, and provides a driving method of a plasma display panel capable of stably causing the writing discharge without reducing the driving voltage margin of the writing operation.
SUMMARY OF THE INVENTION
The present invention provides a driving method of a plasma display panel. The plasma display panel has the following elements:

    
    
        a first substrate;
        a plurality of display electrode pairs that are disposed on the first substrate and formed of scan electrodes and sustain electrodes arranged alternately by two and in parallel;
        a second substrate faced to the first substrate through a discharge space;
        a plurality of data electrodes disposed on the second substrate in the direction crossing the display electrode pairs; and
        a barrier rib disposed between the first substrate and second substrate so as to separate main discharge cells for causing main discharge and priming discharge cells that cause priming discharge with two adjacent scan electrodes of the plurality of scan electrodes.

Here, each main discharge cell is formed of a display electrode pair and a data electrode. In this method, one field time period is formed of a plurality of subfields having an initialization time period, a writing time period, and a sustaining time period. The writing time period has an odd-numbered line writing time period and an even-numbered line writing time period. In the odd-numbered line writing time period, a writing operation is performed in the main discharge cell having an odd-numbered scan electrode, and in the even-numbered line writing time period, a writing operation is performed in the main discharge cell having an even-numbered scan electrode. In the odd-numbered line writing time period, a scan pulse is sequentially applied to the odd-numbered scan electrode, and voltage is applied to the even-numbered scan electrode. This voltage is used for causing priming discharge in the priming discharge cell between the even-numbered scan electrode and the odd-numbered scan electrode to which the scan pulse has been applied. In the even-numbered line writing time period, a scan pulse is sequentially applied to the even-numbered scan electrode, and voltage is applied to the odd-numbered scan electrode. This voltage is used for causing priming discharge in the priming discharge cell between the odd-numbered scan electrode and the even-numbered scan electrode to which the scan pulse has been applied.

    
    





BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view showing a configuration of a panel in accordance with a first exemplary embodiment of the present invention.
FIG. 2 is a sectional view of the panel.
FIG. 3 is an electrode array diagram of the panel.
FIG. 4 is a driving waveform diagram of the panel.
FIG. 5 is a driving waveform diagram of a panel in accordance with a second exemplary embodiment of the present invention.



DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
First Exemplary Embodiment
A panel in accordance with the first exemplary embodiment of the present invention will be described hereinafter with reference to the following drawings. FIG. 1 is an exploded perspective view showing a configuration of the panel in accordance with the first exemplary embodiment of the present invention. FIG. 2 is a sectional view of the panel. Glass front substrate 21 as the first substrate and back substrate 31 as the second substrate are faced to each other on the opposite sides of a discharge space, and the discharge space is filled with mixed gas of neon and xenon. The mixed gas emits ultraviolet rays with discharge.
Display electrode pairs formed of scan electrodes 22 and sustain electrodes 23 are disposed on front substrate 21 in parallel with each other. At this time, scan electrodes 22 and sustain electrodes 23 are arranged alternately by two so as to provide the configuration of sustain electrode 23—scan electrode 22—scan electrode 22—sustain electrode 23—and so forth. Scan electrode 22 and sustain electrode 23 are formed of transparent electrodes 22a and 23a and metal buses 22b and 23b disposed on transparent electrodes 22a and 23a, respectively. Light absorbing layers 28 made of black materials are disposed between scan electrode 22 and scan electrode 22 and between sustain electrode 23 and sustain electrode 23. Projections 22b′ of metal buses 22b of scan electrodes 22 are projected above light absorbing layers 28. Dielectric layer 24 and protective layer 25 are formed so as to cover scan electrodes 22, sustain electrodes 23, and light absorbing layers 28.
A plurality of data electrodes 32 are formed in parallel on back substrate 31 in the intersecting direction with scan electrodes 22 and sustain electrodes 23. Dielectric layer 33 is formed so as to cover data electrodes 32. Barrier ribs 34 for separating main discharge cells 40 are formed on dielectric layer 33.
Each barrier rib 34 is formed of longitudinal wall unit 34a extending in parallel with data electrodes 32 and lateral wall unit 34b that forms main discharge cells 40 and forms clearance unit 41 between main discharge cells 40. As a result, barrier ribs 34 form a main discharge cell row having a plurality of main discharge cells 40 interconnected along a display electrode pair, and form clearance unit 41 between adjacent main discharge cell rows. Here, the display electrode pair is formed of a pair of scan electrode and sustain electrode, as discussed above. Projection 22b′ is formed in clearance unit lying on the side of two adjacent scan electrodes, of clearance units 41, and this clearance unit works as priming discharge cell 41a. In other words, clearance units 41 have projection 22b′ and hence work as priming discharge cells 41a every other unit. Clearance unit 41b lies on the side of two adjacent sustain electrodes.
Top parts of barrier ribs 34 are formed flat so as to abut on front substrate 21. This shape is employed for preventing interference between adjacent discharge cells, especially preventing a malfunction such as a writing error from being caused by the priming that is generated by writing discharge of the adjacent discharge cells in the writing time period. Further, this shape is employed for preventing a malfunction where the wall charge of main discharge cell 40 adjacent to priming discharge cell 41a decreases to cause bad writing. In the first embodiment of the present invention, the step height of barrier ribs 34 is set at 10 μm or shorter. This value is determined based on an experimental result where adjacent main discharge cells 40 interfere with each other at step height of 10 μm or longer and hence priming discharge cell 41a and main discharge cell 40 interfere with each other.
Phosphor layers 35 are formed on the side surfaces of barrier ribs 34 and the surfaces of dielectric layer 33 corresponding to main discharge cells 40 separated by barrier ribs 34. Phosphor layer 35 is not formed on the priming discharge cell 41 side in FIG. 1; however, phosphor layer 35 may be formed.
Dielectric layer 33 is formed so as to cover data electrodes 32 in the above description; however, dielectric layer 33 is not necessarily required.
FIG. 3 is an electrode array diagram of the panel of the first embodiment of the present invention. In the row direction, m rows of data electrodes D1 to Dm (data electrodes 32 in FIG. 1) are disposed. In the column direction, n columns of scan electrodes SC1 to SCn (scan electrodes 22 in FIG. 1) and n columns of sustain electrodes SU1 to SUn (sustain electrodes 23 in FIG. 1) are disposed alternately by two so as to provide the configuration of sustain electrode SU1—scan electrode SC1—scan electrode SC2—sustain electrode SU2—and so forth. In the first embodiment of the present invention, priming discharge is performed between projections (projections 22b′ in FIG. 1) of adjacent scan electrodes SCp and SCp+1 (p=odd number).
Main discharge cell Ci,j (main discharge cell 40 in FIG. 1) including a pair of electrodes, namely scan electrode SCi (i=1 to n) and sustain electrode SUi, and one data electrode Dj (j=1 to m) is formed in an m×n array in the discharge space. Priming discharge cell PSp (priming discharge cell 41a in FIG. 1) including the projection of scan electrode SCp and the projection of sustain electrode SUp+1 is formed.
Next, a driving waveform for driving the panel, its timing, and an operation of the panel are described hereinafter.
FIG. 4 is a driving waveform diagram of the panel of the first exemplary embodiment of the present invention. One field time period is formed of a plurality of subfields having an initialization time period, a writing time period, and a sustaining time period, in the first embodiment. The writing time period has an odd-numbered line writing time period and an even-numbered line writing time period. In the odd-numbered line writing time period, a writing operation is performed in main discharge cells having odd-numbered scan electrodes, and in the even-numbered line writing time period, a writing operation is performed in main discharge cells having even-numbered scan electrodes. The writing operations of the odd-numbered scan electrode and the even-numbered scan electrode are performed temporally separately. As described below, this operation method is employed for causing the priming discharge using the wall charge sequentially, continuously, and stably. This method can reduce influence of interaction between discharge cells, especially influence of vertically adjacent main discharge cells in the writing time period.
In the first half of the initialization time period, data electrodes D1 to Dm and sustain electrodes SU1 to SUn are kept 0 (V), and a ramp waveform voltage gradually increasing from voltage Vi1 toward voltage Vi2 is applied to scan electrodes SC1 to SCn. Here, voltage Vi1 is set so that the voltage difference between sustain electrodes SU1 to SUn and scan electrodes SC1 to SCn is not higher than the discharge start voltage, and voltage Vi2 is set so that the voltage difference is higher than the discharge start voltage. The first feeble initializing discharge occurs between scan electrodes SC1 to SCn and sustain electrodes SU1 to SUn, and the first feeble initializing discharge occurs between scan electrodes SC1 to SCn and data electrodes D1 to Dm, respectively, while the ramp waveform voltage increases. Negative wall voltage is accumulated on scan electrodes SC1 to SCn, and positive wall voltage is accumulated on data electrodes D1 to Dm and sustain electrodes SU1 to SUn. Here, the wall voltage on the electrodes means the voltage generated by the wall charges accumulated on the dielectric layer covering the electrodes or on the phosphor layer. At this time, scan electrodes SC1 to SCn are at an equal voltage, and hence cause no discharge in priming discharge cell PSp.
In the last half of the initialization time period, sustain electrodes SU1 to SUn are kept at positive voltage Ve, and a ramp waveform voltage gradually decreasing from voltage Vi3 toward voltage Vi4 is applied to scan electrodes SC1 to SCn. Here, voltage Vi3 is set so that the voltage difference between sustain electrodes SU1 to SUn and scan electrodes SC1 to SCn is not higher than the discharge start voltage, and voltage Vi4 is set so that the voltage difference is higher than the discharge start voltage. The second feeble initializing discharges occur between scan electrodes SC1 to SCn and sustain electrodes SU1 to SUn, and the second feeble initializing discharges occur between scan electrodes SC1 to SCn and data electrodes D1 to Dm, respectively, while the ramp waveform voltage decreases. The negative wall voltage on scan electrodes SC1 to SCn and positive wall voltage on sustain electrodes SU1 to SUn are reduced, positive wall voltage on data electrodes D1 to Dm is adjusted to a value suitable for the writing operation. At this time, also, scan electrodes SC1 to SCn are at an equal voltage, and hence cause no discharge in priming discharge cell PSp. Thus, the initializing operation is finished.
In the odd-numbered line writing time period, odd-numbered scan electrode SCp is temporarily kept at voltage Vc. Voltage Vq is applied to even-numbered scan electrode SCp+1 to cause discharge in priming discharge cell PSp between scan electrode SCp+1 and odd-numbered scan electrode SCp adjacent to it. Next, when scan pulse voltage Va is applied to first scan electrode SC1, priming discharge occurs in priming discharge cell PS1 between scan electrode SC1 and second scan electrode SC2, and the priming is supplied into main discharge cells C1,1 to C1,m. At this time, when positive writing pulse Vd is applied to data electrode Dk (k is integer 1 to m) corresponding to an image signal to be displayed, discharge occurs in the intersecting part of data electrode Dk and scan electrode SC1 and results in discharge between sustain electrode SU1 and scan electrode SC1 of corresponding discharge cell C1,k. Positive wall voltage is accumulated on scan electrode SC1 in main discharge cell C1,k, negative wall voltage is accumulated on sustain electrode SU1, and the writing operation of the first row is finished. At this time, positive wall voltage is accumulated on scan electrode SC1 and negative wall voltage is accumulated on scan electrode SC2 in priming discharge cell PS1.
Similarly, the writing operations of odd-numbered main discharge cells C3,k, C5,k, and so forth are performed.
In the even-numbered line writing time period, even-numbered scan electrode SCp+1 is temporarily kept at voltage Vc. Voltage Vq is applied to odd-numbered scan electrode SCp to cause discharge in priming discharge cell PSp between scan electrode SCp and odd-numbered scan electrode SCp+1 adjacent to it. Next, when scan pulse voltage Va is applied to second scan electrode SC2, priming discharge occurs in priming discharge cell PS1 between scan electrode SC2 and first scan electrode SC1. This priming discharge becomes stable and its discharge delay is reduced, because the positive wall voltage accumulated on scan electrode SC1 in priming discharge cell PS1 and the negative wall voltage accumulated on sustain electrode SC2 are added. The priming is supplied into main discharge cells C2,1 to C2,m. At this time, when positive writing pulse Vd is applied to data electrode Dk corresponding to the image signal to be displayed, discharge occurs in the intersecting part of data electrode Dk and scan electrode SC2 and results in discharge between sustain electrode SU2 and scan electrode SC2 of corresponding discharge cell C2,k. Positive wall voltage is accumulated on scan electrode SC2 in main discharge cell C2,k, negative wall voltage is accumulated on sustain electrode SU2, and the writing operation of the second row is finished. At this time, the wall voltages in priming discharge cell PS1 are inverted, negative wall voltage is accumulated on scan electrode SC1 in priming discharge cell PS1, and positive wall voltage is accumulated on scan electrode SC2.
Similarly, the writing operations of even-numbered main discharge cells C4,k, C6,k, and so forth are performed. The writing time period is thus finished.
In the sustaining time period, scan electrodes SC1 to SCn and sustain electrodes SU1 to SUn are temporarily returned to 0 (V), and then positive sustaining pulse voltage Vs is applied to scan electrodes SC1 to SCn. At this time, the voltage between the upper parts of scan electrode SCi and sustain electrode SUi in discharge cell Ci,k having undergone writing discharge becomes higher than the discharge start voltage. That is because positive sustaining voltage Vs and the wall voltages accumulated on scan electrode SCi and sustain electrode SUi in the writing time period are added to the discharge start voltage. Thus, sustaining discharge occurs in discharge cell Ci,k. After that, similarly, sustaining pulses are alternately applied to scan electrodes SC1 to SCn and sustain electrodes SU1 to SUn. Thus, sustaining discharge is continuously repeated by the number of sustaining pulses in discharge cell Ci,k having undergone writing discharge. At this time, scan electrodes SC1 to SCn are at an equal voltage, and hence cause no discharge in priming discharge cell PSp.
In the initialization time period of a subsequent subfield, sustain electrodes SU1 to SUn are kept at positive voltage Ve, and a ramp waveform voltage gradually decreasing toward voltage Vi4 is applied to scan electrodes SC1 to SCn. In main discharge cell Ci,k where sustaining discharge has occurred, feeble initializing discharge occurs between scan electrodes SC1 to SCn and sustain electrodes SU1 to SUn and feeble initializing discharge occurs between scan electrodes SC1 to SCn and data electrodes D1 to Dm. The wall voltage on scan electrodes SC1 to SCn and the wall voltage on sustain electrodes SU1 to SUn are decreased, and the positive wall voltage on data electrodes D1 to Dm is adjusted to a voltage suitable for the writing operation. At this time, also, scan electrodes SC1 to SCn are at an equal voltage, and hence cause no discharge in priming discharge cell PSp.
Operations in the writing time period and the sustaining time period after the initialization time period, the driving waveform of a subsequent subfield, and the operation of the panel are the same as those discussed above.
Here, an operation of a priming discharge cell is especially described again, for describing the reason why the writing time period is divided into the odd-numbered line writing time period and even-numbered line writing time period. In priming discharge cell PSp, discharge occurs only when the voltage applied to odd-numbered scan electrode SCp is different from voltage applied to even-numbered scan electrode SCp+1, so that the attention is required to be focused only on the writing time period.
In the odd-numbered line writing time period of the initial subfield, negative scan pulse voltage Va is applied to odd-numbered scan electrode SCp, and positive voltage Vq is applied to even-numbered scan electrode SCp+1, thereby causing priming discharge. Positive wall voltage is accumulated on odd-numbered scan electrode SCp, and negative wall voltage is accumulated on even-numbered scan electrode SCp+1, in priming discharge cell PSp.
In the subsequent even-numbered line writing time period, negative scan pulse voltage Va is further applied to even-numbered scan electrode SCp+1 on which the negative wall voltage is accumulated, and positive voltage Vq is further applied to odd-numbered scan electrode SCp on which the positive wall voltage is accumulated, thereby causing priming discharge. Thus, this priming discharge becomes stable and its discharge delay is reduced, because the wall voltages are further added to the voltages that have been applied to the electrodes. Then, positive wall voltage is accumulated on even-numbered scan electrode SCp+1, and negative wall voltage is accumulated on odd-numbered scan electrode SCp, in priming discharge cell PSp.
In the odd-numbered line writing time period of the next subfield, negative scan pulse voltage Va is further applied to odd-numbered scan electrode SCp on which the negative wall voltage is accumulated, and positive voltage Vq is further applied to even-numbered scan electrode SCp+1 on which the positive wall voltage is accumulated, thereby causing priming discharge. Thus, this priming discharge also becomes stable and its discharge delay is reduced. Then, positive wall voltage is accumulated on odd-numbered scan electrode SCp, and negative wall voltage is accumulated on even-numbered scan electrode SCp+1, in priming discharge cell PSp.
After that, similarly, the wall voltages always work to increase the priming discharge, so that the priming discharge also becomes stable and its discharge delay is reduced. Thus, by dividing the writing time period into the odd-numbered line writing time period and even-numbered line writing time period, the priming discharge can be made stable and its discharge delay can be reduced.
In the above-mentioned description, in the initialization time period of the first subfield, a full cell initializing operation of performing initializing discharge in all main discharge cells is performed. In the initialization time periods of the next subfield and later, a selective initializing operation is performed where the main discharge cell having undergone sustaining discharge is selectively initialized. However, these initializing operations may be arbitrarily combined.
Second Exemplary Embodiment
The configuration of the panel in accordance with the second exemplary embodiment of the present invention is the same as that of the first exemplary embodiment. In the driving method of the second exemplary embodiment, the writing time period is divided into an odd-numbered line writing time period and an even-numbered line writing time period, and these time periods are performed temporally separately, similarly to that of the first exemplary embodiment. The second exemplary embodiment differs from the first exemplary embodiment in that the second embodiment has subfields where the initialization time period is temporally separately divided into an odd-numbered line initialization time period and an even-numbered line initialization time period. In other words, of a plurality of subfields, at least one subfield has the odd-numbered line initialization time period in which main discharge cells having odd-numbered scan electrodes are initialized and the even-numbered line initialization time period in which main discharge cells having even-numbered scan electrodes are initialized. The odd-numbered line initialization time period is disposed just before the odd-numbered line writing time period, and the even-numbered line initialization time period is disposed just before the even-numbered line writing time period.
Next, a driving waveform for driving the panel, its timing, and an operation of the panel are described hereinafter. FIG. 5 is a driving waveform diagram of the panel of the second exemplary embodiment of the present invention.
In the first half of the odd-numbered line initialization time period, data electrodes D1 to Dm and sustain electrodes SU1 to SUn are kept 0 (V), and a ramp waveform voltage gradually increasing from voltage Vi1 toward voltage Vi2 is applied to odd-numbered scan electrode SCp. While the ramp waveform voltage increases, the first feeble initializing discharge occurs in the odd-numbered main discharge cell, negative wall voltage is accumulated on odd-numbered scan electrodes SCp, and positive wall voltage is accumulated on data electrodes D1 to Dm and odd-numbered sustain electrodes SUp. In the last half of the odd-numbered line initialization time period, sustain electrodes SU1 to SUn are kept at positive voltage Ve, and a ramp waveform voltage gradually decreasing from voltage Vi3 toward voltage Vi4 is applied to odd-numbered scan electrodes SCp. While the ramp waveform voltage decreases, the second feeble initializing discharge occurs in the odd-numbered main discharge cell, the negative wall voltage on odd-numbered scan electrodes SCp and positive wall voltage on odd-numbered sustain electrodes SUp are reduced, positive wall voltage on data electrodes D1 to Dm is adjusted to a value suitable for the writing operation.
The discharge occurring in the odd-numbered main discharge cell and the behavior of the wall voltage following the discharge have been described. No discharge occurs in main discharge cells on the even-numbered line side.
At this time, the discharge and wall voltage behave as follows in priming discharge cell PSp. In the first half of the odd-numbered line initialization time period, even-numbered scan electrode SCp+1 is kept 0 (V), and a ramp waveform voltage gradually increasing toward voltage Vi2 exceeding the discharge start voltage is applied to odd-numbered scan electrode SCp. Therefore, first feeble initializing discharge occurs between odd-numbered scan electrode SCp and even-numbered scan electrode SCp+1. Negative wall voltage is accumulated on odd-numbered scan electrodes SCp, and positive wall voltage is accumulated on even-numbered scan electrode SCp+1, in priming discharge cell PSp. In the last half of the odd-numbered line initialization time period, a ramp waveform voltage gradually decreasing from voltage Vi3 toward voltage Vi4 is applied to odd-numbered scan electrodes SCp. However, voltage Vr for suppressing discharge is applied to even-numbered scan electrode SCp+1. Therefore, discharge does not occur in this electrode, or even if discharge occurs the wall voltages are not largely reduced.
Thus, before the odd-numbered line writing time period, negative wall voltage is accumulated on odd-numbered scan electrodes SCp and positive wall voltage is accumulated on even-numbered scan electrode SCp+1 in priming discharge cell PSp.
In the subsequent odd-numbered line writing time period, negative scan pulse voltage Va is further applied to odd-numbered scan electrode SCp on which the negative wall voltage has been accumulated, and positive voltage Vq is further applied to even-numbered scan electrode SCp+1 on which the positive wall voltage has been accumulated, thereby causing priming discharge. Thus, the priming discharge in the writing time period of the first subfield also becomes stable, and its discharge delay is reduced. Then, positive wall voltage is accumulated on odd-numbered scan electrode SCp and negative wall voltage is accumulated on even-numbered scan electrode SCp+1 in priming discharge cell PSp.
In the first half of the even-numbered line initialization time period, data electrodes D1 to Dm and sustain electrodes SU1 to SUn are kept 0 (V), and a ramp waveform voltage gradually increasing from voltage Vi1 toward voltage Vi2 is applied to even-numbered scan electrode SCp+1. In the last half of the even-numbered line initialization time period, sustain electrodes SU1 to SUn are kept at positive voltage Ve, and a ramp waveform voltage gradually decreasing from voltage Vi3 toward voltage Vi4 is applied to even-numbered scan electrodes SCp. In this time period, an initializing operation similar to that in the odd-numbered main discharge cell is performed in the even-numbered main discharge cell.
At this time, the positive wall voltage has been accumulated on odd-numbered scan electrode SCp and negative wall voltage has been accumulated on even-numbered scan electrode SCp+1 in priming discharge cell PSp. Therefore, even when the increasing ramp waveform voltage is applied to even-numbered scan electrode SCp+1 in the first half of the even-numbered line initialization time period, the wall voltages work in the canceling direction of the ramp waveform voltage. Therefore, discharge does not occur, or even if discharge occurs the wall voltages are not largely reduced. Even when the decreasing ramp waveform voltage is further applied to even-numbered scan electrode SCp+1 in the last half of the even-numbered line initialization time period, voltage Vr for suppressing discharge is applied to odd-numbered scan electrode SCp. Therefore, discharge does not occur in this electrode, or even if discharge occurs the wall voltages are not largely reduced.
In the subsequent even-numbered line writing time period, negative scan pulse voltage Va is further applied to even-numbered scan electrode SCp+1 on which the negative wall voltage has been accumulated, and positive voltage Vq is further applied to odd-numbered scan electrode SCp on which the positive wall voltage has been accumulated, thereby causing priming discharge. The wall voltages are thus added to the voltages that have been applied to the electrodes, so that the priming discharge at this time also becomes stable and its discharge delay is reduced. Then, positive wall voltage is accumulated on even-numbered scan electrode SCp+1 and negative wall voltage is accumulated on odd-numbered scan electrode SCp in priming discharge cell PSp.
The driving method of the panel of the second exemplary embodiment of the present invention employs the subfields where the initialization time period is temporally separately divided into the odd-numbered line initialization time period and the even-numbered line initialization time period, as discussed above. Therefore, the priming discharge in the writing time period of the first subfield also becomes stable, and its discharge delay is reduced.
The odd-numbered line initialization time period and the even-numbered line initialization time period do not need to be disposed in every subfield. When one set of the time periods is simply disposed per one field or several fields, for example, the priming discharge can be stabilized.
The present invention can provide a driving method of a plasma display panel capable of stably causing the writing discharge without reducing the driving voltage margin of the writing operation.
INDUSTRIAL APPLICABILITY
In a driving method of a panel of the present invention, writing discharge can be stably caused without reducing the driving voltage margin of the writing operation, so that this driving method is useful as a driving method of a panel used in a wall-mounted TV or a large monitor.

## Claims

1. A driving method of a plasma display panel,
the plasma display panel comprising:
a first substrate;
a plurality of display electrode pairs that are disposed on the first substrate and formed of scan electrodes and sustain electrodes, the scan electrodes and the sustain electrodes being arranged alternately by two and in parallel;
a second substrate faced to the first substrate through a discharge space;
a plurality of data electrodes disposed on the second substrate and in a direction crossing the display electrode pairs; and
a barrier rib disposed between the first substrate and the second substrate so as to separate main discharge cells for causing main discharge and priming discharge cells for causing priming discharge with two adjacent scan electrodes of the plurality of scan electrodes, each of the main discharge cells being formed of the display electrode pair and the data electrode,

the driving method of the plasma display panel comprising:
forming one field including a plurality of subfields having an initialization time period, a writing time period, and a sustaining time period;
dividing the writing time period into an odd-numbered line writing time period and an even-numbered line writing time period, a writing operation being performed in the main discharge cell having an odd-numbered scan electrode in the odd-numbered line writing time period, a writing operation being performed in the main discharge cell having an even-numbered scan electrode in the even-numbered line writing time period;
sequentially applying a scan pulse to an odd-numbered scan electrode and applying voltage to an even-numbered scan electrode in the odd-numbered line writing time period, the voltage being used for causing priming discharge in the priming discharge cell between the even-numbered scan electrode and the odd-numbered scan electrode to which the scan pulse has been applied; and
sequentially applying a scan pulse to an even-numbered scan electrode and applying voltage to an odd-numbered scan electrode in the even-numbered line writing time period, the voltage being used for causing priming discharge in the priming discharge cell between the odd-numbered scan electrode and the even-numbered scan electrode to which the scan pulse has been applied.

2. The driving method of the plasma display panel according to claim 1, wherein
in at least one of the plurality of subfields, the initialization time period has an odd-numbered line initialization time period and an even-numbered line initialization time period, an initializing operation being performed in the main discharge cell having an odd-numbered scan electrode in the odd-numbered line initialization time period, an initializing operation being performed in the main discharge cell having an even-numbered scan electrode in the even-numbered line initialization time period, and
the odd-numbered line initialization time period is disposed just before the odd-numbered line writing time period, and the even-numbered line initialization time period is disposed just before the even-numbered line writing time period.