Abstract:
A plasma display panel and a driving method thereof that is capable of improving a discharge efficiency as well as preventing a crosstalk. In the panel, an address electrode is included in each discharge cell making a unit pixel of the plasma display panel. A plurality of second sustain electrodes are positioned at each periphery of the discharge cell in a direction crossing the address electrode to receive a second sustaining pulse. At least one of first sustain electrode is positioned at the center of the discharge cell in a direction crossing the address electrode to receive a first sustaining pulse applied alternately with respect to the second sustaining pulse.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a plasma display panel, and more particularly to a plasma display panel and a driving method thereof that is capable of improving discharge efficiency as well as preventing a crosstalk.  
           [0003]    2. Description of the Related Art  
           [0004]    Generally, a plasma display panel (PDP) is a display device utilizing a visible light emitted from a fluorescent body when an ultraviolet ray generated by a gas discharge excites the fluorescent body. The PDP has an advantage in that it has a thinner thickness and a lighter weight in comparison to the existent cathode ray tube (CRT) and is capable of realizing a high resolution and a large-scale screen. The PDP includes a plurality of discharge cells arranged in a matrix pattern, each of which makes one pixel of a field.  
           [0005]    [0005]FIG. 1 is a perspective view showing a discharge cell structure of a conventional three-electrode, alternating current (AC) surface-discharge PDP.  
           [0006]    Referring to FIG. 1, a discharge cell of the conventional three-electrode, AC surface-discharge PDP includes a scan/sustain electrode  12 Y and a common sustain electrode  12 Z provided on an upper substrate  10 , and an address electrode  20 X provided on a lower substrate  18 .  
           [0007]    The scan/sustain electrode  12 Y and the common sustain electrode  12 Z are transparent electrodes made from indium-tin-oxide (ITO). Since the ITO has a high resistance value, a signal is applied via bus electrodes  13 YB and  13 ZB to thereby apply an uniform voltage to each discharge cell  
           [0008]    On the upper substrate  10  provided with the scan/sustain electrode  12 Y and the common sustain electrode  12 Z in parallel, an upper dielectric layer  14  and a protective film  16  are disposed. Wall charges generated by plasma discharge are accumulated on the upper dielectric layer  14 . The protective film  16  prevents a damage of the upper dielectric layer  14  caused by a sputtering during the plasma discharge and improves the emission efficiency of secondary electrons. This protective film  16  is usually made from magnesium oxide (MgO).  
           [0009]    A lower dielectric layer  22 , barrier ribs  24  are formed on the lower substrate  18  provided with the address electrode  20 X. The surfaces of the lower dielectric layer  22  and the barrier ribs  24  are coated with a fluorescent layer  26 . The address electrode  20 X is formed in a direction crossing the scan/sustain electrode  12 Y and the common sustain electrode  12 Z.  
           [0010]    The barrier rib  24  is formed in parallel to the address electrode  20 X to prevent an ultraviolet ray and a visible light generated by a discharge from being leaked to the adjacent discharge cells. The fluorescent layer  26  is excited by an ultraviolet ray generated during the plasma discharge to generate any one of red, green and blue visible light rays. An inactive gas for a gas discharge is injected into a discharge space defined between the upper and lower substrate  10  and  18  and the barrier rib  24 .  
           [0011]    [0011]FIG. 2 represents an arrangement structure of the overall electrode lines and discharge cells of the PDP shown in FIG. 1.  
           [0012]    Referring to FIG. 2, a discharge cell  28  is positioned at each intersection among the scan/sustain electrode lines Y, the common sustain electrode lines Z and the address electrode lines X. The outer edge of the scan/sustain electrode line Y and the common sustain electrode lines Z is provided with the bus electrodes YB and ZB. The barrier ribs  24  are formed in parallel to the address electrode lines X.  
           [0013]    Such a three-electrode AC surface-discharge PDP drives one frame, which is divided into various sub-fields having a different emission number, so as to realize gray levels of a picture. Each sub-field is again divided into a reset period for uniformly causing a discharge, an address period for selecting the discharge cell and a sustain period for realizing the gray levels depending on the discharge number. When it is intended to display a picture of 256 gray levels, a frame interval equal to 1/60 second (i.e. 16.67 msec) is divided into 8 sub-fields. Each of the 8 sub-fields is divided into a reset period, an address period and a sustain period. The reset period and the address period of each sub-field are equal every sub-field, whereas the sustain period and the discharge number are increased at a ration of 2 n  (wherein n=0, 1, 2, 3, 4, 5, 6 and 7) at each sub-field. Since the sustain period becomes different at each sub-field as mentioned above, the gray levels of a picture can be expressed. In order to express the gray levels, driving waveforms as shown in FIG. 3 are applied to each electrode line of the PDP for each sub-field.  
           [0014]    Referring to FIG. 3, one sub-field is divided into a reset period for initializing the entire field, an address period for scanning the entire field on a line-sequence basis to write a data, and a sustain period for keeping a light-emission state of the cells into which a data is written.  
           [0015]    First, in the reset period, a reset pulse VR is applied to the common sustain electrode line Z to generate a reset discharge between the common sustain electrode line Z and the scan/sustain electrode line Y. When the reset discharge is generated between the common sustain electrode line Z and the scan/sustain electrode line Y, priming charged particles and wall charges are formed at each discharge cell.  
           [0016]    In the address period, a scanning pulse −Vs is sequentially applied to the scan/sustain electrode lines Y, and a data pulse Vd synchronized with the scanning pulse −Vs is applied to the address electrode lines X. At this time, a desired level of direct current voltage for preventing an erroneous discharge is applied to the common sustain electrode lines Z.  
           [0017]    In the sustain period, sustaining pulses Vsus having the same pulse width and voltage are alternately applied to the scan/sustain electrode lines Y and the common sustain electrode lines Z to make a sustain discharge of the discharge cells selected by an address discharge.  
           [0018]    As described above, the conventional PDP allows sustaining pulses to be alternately applied to the scan/sustain electrode lines and the common sustain electrodes formed in adjacent to each other in the sustain period. For this reason, an erroneous discharge may be caused between the scan/sustain electrode lines and the common sustain electrodes formed adjacently with having the barrier ribs therebetween.  
           [0019]    Further, since the scan/sustain electrode lines and the common sustain electrode lines are formed at the center of the discharge cell, the sustain discharge concentrates on the middle portion of the upper substrate to reduce a utility of the discharge space. In other words, a discharge area of the sustain discharge is reduced to cause a deterioration in the light-emission efficiency.  
           [0020]    In addition, since the barrier ribs are formed in parallel to the address electrodes, a light generated at a specific discharge cell is provided at the upper/lower portion of the specific discharge cell. In other words, a crosstalk may be generated between the discharge cells arranged in a direction perpendicular to the barrier ribs.  
           [0021]    In order to improve the discharge efficiency, there has been suggested a five-electrode, AC surface-discharge PDP as shown in FIG. 4.  
           [0022]    Referring to FIG. 4, the conventional five-electrode, AC surface-discharge PDP includes first and second trigger electrodes  34 Y and  34 Z provided on an upper substrate  30  in such a manner to be positioned at the center of a discharge cell, first and second sustain electrodes  32 Y and  32 Z provided on the upper substrate  30  in such a manner to be positioned at the edge of the discharge cell, and an address electrode  42 X provided at a lower substrate in a direction crossing the trigger electrodes  34 Y and  34 Z and the first and second sustain electrodes  32 Y and  32 Z.  
           [0023]    On the upper substrate  30  provided with the first sustain electrode  32 Y, the first trigger electrode  34 Y, the second trigger electrode  34 Z and the second sustain electrode  32 Z in parallel, an upper dielectric layer  36  and a protective layer  38  are disposed. On the other hand, a lower dielectric layer  44  and a barrier rib  46  are formed on a lower substrate  40  provided with the address electrode  42 X, and a fluorescent layer  48  is coated on the surfaces of the lower dielectric layer  44  and the barrier ribs  46 .  
           [0024]    The trigger electrodes  34 Y and  34 Z spaced at a narrow distance Ni at the center of the discharge cell are supplied with an alternating pulse in the sustain period to initiate a sustain discharge. The first and second sustain electrodes  32 Y and  32 Z spaced at a wide distance Wi at the edge of the discharge cell are used to keep a plasma discharge after the discharge was initiated by the trigger electrodes  34 Y and  34 Z.  
           [0025]    An operation process of the five-electrode AC surface-discharge PDP will be described in detail with reference to FIG. 5 below. FIG. 5 is a section view representing a state of rotating the upper substrate by 90° with respect to the lower substrate so as to show up the overall electrode structure within one discharge cell.  
           [0026]    First, in the reset period, a reset pulse is applied to the second trigger electrode  34 Z of the discharge cell to generate a reset discharge for initializing the discharge cell.  
           [0027]    In the address period, a scanning pulse is sequentially applied to the first trigger electrode  34 Y and a data pulse synchronized with the scanning pulse is applied to the address electrode X. At this time, an address discharge is generated at the discharge cells supplied with a data.  
           [0028]    In the sustain period, a first alternating current pulse is alternately applied to the first and second trigger electrodes  34 Y and  34 Z. Also, a second alternating current pulse having a higher voltage level than the first alternating current pulse is applied to the first and second electrodes  32 Y and  32 Z. When the first alternating current pulse is applied, a discharge is initiated between the first and second trigger electrodes  34 Y and  34 Z. At this time, the first and second sustain electrodes  32 Y and  32 Z generate a sustain discharge by a priming effect of charged particles caused by said discharge between the first and second trigger electrodes  34 Y and  34 Z.  
           [0029]    In such a conventional five-electrode PDP, a sustain electrode is initiated by utilizing the trigger electrodes  34 Y and  34 Z, to thereby cause a sustain discharge having a long discharge path.  
           [0030]    However, a sustaining pulse is alternately applied to the first and second sustain electrodes formed adjacently each other during the sustain period. Accordingly, an erroneous discharge may be generated between the first and second sustain electrodes formed in parallel with the barrier ribs therebetween.  
           [0031]    Furthermore, since the barrier ribs are formed in parallel to the address electrode lines, a light generated at a specific discharge cell is applied to the discharge cells provided at the upper/lower portions of the specific discharge cell. In other words, a crosstalk may be generated between the discharge cells arranged in parallel in a direction perpendicular to the barrier ribs.  
         SUMMARY OF THE INVENTION  
         [0032]    Accordingly, it is an object of the present invention to provide a plasma display panel and a driving method that are capable of improving a discharge efficiency.  
           [0033]    A further object of the present invention is to provide a plasma display panel and a driving method that are capable of preventing a crosstalk between the discharge cells.  
           [0034]    In order to achieve these and other objects of the invention, a plasma display panel according to one aspect of the present invention includes address electrode included in each discharge cell making a unit pixel of the plasma display panel; a plurality of second sustain electrodes positioned at each periphery of the discharge cell in a direction crossing the address electrode to receive a second sustaining pulse; and at least one of first sustain electrode positioned at the center of the discharge cell in a direction crossing the address electrode to receive a first sustaining pulse applied alternately with respect to the second sustaining pulse. Herein, the first sustain electrode is provided between the second sustain electrodes.  
           [0035]    The plasma display panel further includes a bus electrode arranged in parallel to the first sustain electrode at the center of the first sustain electrode. Otherwise, the plasma display panel further includes bus electrodes arranged in parallel to the first sustain electrode at each edge of the first sustain electrode.  
           [0036]    The plasma display panel further includes two first sustain electrodes positioned at the center of the discharge cell and provided between the second sustain electrodes.  
           [0037]    The plasma display panel further includes a first barrier rib formed in parallel to the address electrode. Also, the plasma display panel further includes a second barrier rib formed in a direction crossing the first barrier rib. Herein, the second barrier rib is provided at an interface of the discharge cells.  
           [0038]    The plasma display panel further includes a scan/sustain driver connected to the first sustain electrode to apply the scanning pulse and the first sustaining pulse; and a common sustaining driver connected to the second sustain electrode to apply the second sustaining pulse. Otherwise, the plasma display panel further includes a scan/sustain driver connected to the second sustain electrode to apply the scanning pulse and the first sustaining pulse; and a common sustaining driver connected to the first sustain electrode to apply a reset pulse and the first sustaining pulse.  
           [0039]    The plasma display panel further includes a dielectric layer formed in such a manner to cover the first and second sustain electrodes; and at least two floating electrodes formed in parallel to the first and second sustain electrodes at the rear side of the dielectric layer. Herein, the floating electrodes are provided under the second sustain electrodes.  
           [0040]    A method of driving a plasma display panel according to another aspect of the present invention includes the steps of applying a reset pulse to at least one electrode of a first sustain electrode and second sustain electrodes so as to initialize a discharge cell; applying a scanning pulse to the first sustain electrode so as to select the discharge cells to be turned on; applying a data pulse synchronized with the scanning pulse to the address electrode; and alternately applying the sustaining pulse to the first and second sustain electrodes so as to discharge the discharge cells to be turned on.  
           [0041]    A method of driving a plasma display panel according to still another aspect of the present invention includes the steps of applying a reset pulse to at least one electrode of a first sustain electrode so as to initialize a discharge cell; applying a scanning pulse to the second sustain electrodes so as to select the discharge cells to be turned on; applying a data pulse synchronized with the scanning pulse to the address electrode; and alternately applying the sustaining pulse to the first and second sustain electrodes so as to discharge the discharge cells to be turned on.  
           [0042]    A plasma display panel according to still another aspect of the present invention includes a sustain electrode pair positioned at each periphery of discharge cell on an upper substrate; first and second trigger electrodes formed in parallel to the sustain electrode pair between the sustain electrode pair; a dielectric layer coated on the entire surface of the upper substrate in such a manner to cover the sustain electrode pair and the first and second trigger electrodes; and at least two floating electrodes formed in parallel to the sustain electrode pair at the rear side of the dielectric layer. Herein, the floating electrodes are provided under the sustain electrode pair. Each of the floating electrodes has a width smaller than the sustain electrode pair. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0043]    These and other objects of the invention will be apparent from the following detailed description of the embodiments of the present invention with reference to the accompanying drawings, in which:  
         [0044]    [0044]FIG. 1 is a perspective view showing a discharge cell structure of a conventional three-electrode AC surface-discharge plasma display panel;  
         [0045]    [0045]FIG. 2 is a plan view showing an electrode arrangement of the plasma display panel in FIG. 1;  
         [0046]    [0046]FIG. 3 illustrates driving waveforms applied to the plasma display panel in FIG. 1;  
         [0047]    [0047]FIG. 4 is a perspective view showing a discharge cell structure of a conventional five-electrode, AC surface-discharge plasma display panel;  
         [0048]    [0048]FIG. 5 is a section view showing a discharge cell structure of the five-electrode AC surface-discharge plasma display panel shown in FIG. 4;  
         [0049]    [0049]FIG. 6 is a plan view showing an electrode arrangement of a plasma display panel according to a first embodiment of the present invention;  
         [0050]    [0050]FIG. 7 is a block diagram of a driver applying driving waveforms to the electrodes shown in FIG. 6;  
         [0051]    [0051]FIG. 8 illustrates driving waveforms applied to the electrodes shown in FIG. 6;  
         [0052]    [0052]FIG. 9 is a section view representing a sustain discharge generated at the plasma display panel shown in FIG. 6;  
         [0053]    [0053]FIG. 10 is a plan view representing barrier ribs provided additionally at the plasma display panel shown in FIG. 6;  
         [0054]    [0054]FIG. 11 is a plan view showing an electrode arrangement of a plasma display panel according to a second embodiment of the present invention;  
         [0055]    [0055]FIG. 12 is a plan view showing an electrode arrangement of a plasma display panel according to a third embodiment of the present invention;  
         [0056]    [0056]FIG. 13 is a plan view representing barrier ribs provided additionally at the plasma display panel shown in FIG. 12;  
         [0057]    [0057]FIG. 14 is a block diagram showing a configuration of a driving apparatus for the plasma display panel shown in FIG. 12;  
         [0058]    [0058]FIG. 15 is a plan view representing a sustain discharge generated at the plasma display panel shown in FIG. 12;  
         [0059]    [0059]FIG. 16 is a block diagram showing a configuration of a driving apparatus for a plasma display panel according to a fourth embodiment of the present invention;  
         [0060]    [0060]FIG. 17 is a section view showing a discharge cell structure of a plasma display panel according to a fifth embodiment of the present invention; and  
         [0061]    [0061]FIG. 18 is a section view representing an adjacent discharge cell structure of the AC surface-discharge plasma display panel shown in FIG. 17. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0062]    [0062]FIG. 6 is a plan view showing an electrode arrangement of a plasma display panel (PDP) according to a first embodiment of the present invention.  
         [0063]    Referring to FIG. 6, the PDP according to the first embodiment includes address electrode lines X, first and second common sustain electrode lines Z and Z′ formed in a direction crossing the address electrode lines X, and scan/sustain electrode lines Y provided between the first and second common sustain electrode lines Z and Z′.  
         [0064]    A discharge cell  50  is positioned at each intersection among the address electrode lines X, the scan/sustain electrode lines Y, the first common sustain electrode lines Z and the second common sustain electrode lines Z′. The scan/sustain electrode lines Y and the first and second common sustain electrode liens Z and Z′ are transparent electrodes made from indium-tin-oxide (ITO). Since the ITO has a high resistance value, the rear sides of the scan/sustain electrode lines Y and the first and second common sustain electrode lines Z and Z′ are provided with bus electrodes YB, ZB and ZB′, respectively such that a uniform voltage can be applied to all the discharge cells  50 . The scan/sustain electrode lines Y are set to have wider widths than the first and second sustain electrode lines Z and Z′.  
         [0065]    Barrier ribs  52  are formed in parallel to the address electrodes X. The scan/sustain electrode lines Y are positioned at the center of the discharge cell  50 . The first and second common sustain electrode lines Z and Z′ are positioned at the periphery of the discharge cell with having the scan/sustain electrode lines Y therebetween.  
         [0066]    [0066]FIG. 7 shows a driving apparatus for the PDP of FIG. 6.  
         [0067]    Referring to FIG. 7, the PDP driving apparatus includes a scan/sustain driver  54  for driving the scan/sustain electrode lines Y, and a common sustaining driver  56  for driving the first and second common sustain electrode lines Z and Z′. The scan/sustain driver  54  applies a scanning pulse sequentially and a sustaining pulse to the scan/sustain electrode lines Y. The common sustaining driver  56  applies a sustaining pulse to the first and second common sustain electrode lines Z and Z′. The address electrode lines X receive a picture data synchronized with the scanning pulse from an address driver (not shown). In order to express gray levels, driving waveforms as shown in FIG. 8 are applied to the electrode lines of the PDP.  
         [0068]    Referring to FIG. 8, one sub-field is divided into a reset period for initializing the entire field, an address period for scanning the entire field on a line-sequence basis to write a data, and a sustain period for keeping a light-emission state of the cells into which a data is written.  
         [0069]    First, in the reset period, a reset pulse VR is applied to the first and second common sustain electrode lines Z and Z′. The first and second common sustain electrode lines Z and Z′ supplied with the reset pulse VR generate a reset discharge with respect to the scan/sustain electrode lines Y. When the reset discharge occurs, uniform charged particles and wall charges are formed at all the discharge cells  50 .  
         [0070]    In the address period, a scanning pulse −Vs is sequentially applied to the scan/sustain electrode lines Y, and a data pulse Vd synchronized with the scanning pulse −Vs is applied to the address electrode lines X.  
         [0071]    In the sustain period, sustaining pulses Vsus having the same pulse width and voltage are alternately applied to the scan/sustain electrode lines Y and the first and second common sustain electrode lines Z and Z′ to make a sustain discharge of the discharge cells selected by an address discharge.  
         [0072]    A sustain electrode is generated by the scan/sustain electrode lines Y positioned at the center of the discharge cell  50  and the common sustain electrode lines Z and Z′ positioned at the periphery of the discharge cell  50 . In other words, a sustain discharge having a long discharge path is generated between the first and second common sustain electrodes Z and Z′. If a sustain discharge having a long discharge path is generated as mentioned above, then a generated amount of an ultraviolet ray can be not only increased, but also a light-emission area can be enlarged to improve a light-emission efficiency. Herein, elements of the PDP according to the first embodiment having the same construction as those of the PDP shown in FIG. 1 have been given to the same reference numerals.  
         [0073]    According to the first embodiment of the present invention, an erroneous discharge, that is, a crosstalk between the adjacent discharge cells  50  can be prevented. More specifically, the first and second common sustain electrode lines Z and Z′ are supplied with identical pulses in the sustain period. Because the first and second common sustain electrode lines Z and Z′ provided at the periphery of the adjacent discharge cells  50  receives the same pulse, a crosstalk between the discharge cells  50  can be prevented.  
         [0074]    The PDP according to the first embodiment further may include second barrier ribs  58  formed in parallel to the common sustain electrode lines Z and Z′ as shown in FIG. 10. The second barrier ribs  58  are provided at the upper and lower portions of the discharge cell  50  to prevent a light generated by a discharge from being supplied to the discharge cells formed in adjacent to the upper and lower portion thereof.  
         [0075]    [0075]FIG. 11 is a plan view showing an electrode arrangement of a plasma display panel (PDP) according to a second embodiment of the present invention.  
         [0076]    Referring to FIG. 11, the PDP according to the second embodiment includes address electrode lines X, first and second common sustain electrode lines Z and Z′ formed in a direction crossing the address electrode lines X, and scan/sustain electrode lines Y provided between the first and second common sustain electrode lines Z and Z′.  
         [0077]    A discharge cell  50  is positioned at each intersection among the address electrode lines X, the scan/sustain electrode lines Y, the first common sustain electrode lines Z and the second common sustain electrode lines Z′. The scan/sustain electrode lines Y and the first and second common sustain electrode lines Z and Z′ are transparent electrodes made from indium-tin-oxide (ITO). Since the ITO has a high resistance value, the rear sides of the scan/sustain electrode lines Y and the first and second common sustain electrode lines Z and Z′ are provided with bus electrodes YB, YB′, ZB and ZB′, respectively such that a uniform voltage can be applied to all the discharge cells  50 . Please note that, although one bus electrode YB is provided at the scan/sustain electrode line Y in the first embodiment, two bus electrodes YB and YB′ are provided at the scan/sustain electrode Y in the second embodiment.  
         [0078]    In the first embodiment, a single bus electrode YB is provided at the scan/sustain electrode line Y having a large width. If one bus electrode YB is provided at the scan/sustain electrode line Y having a large width, then a voltage drop may occur due to a resistance value of the scan/sustain electrode line Y made from the ITO.  
         [0079]    In light of this, the second embodiment provides two bus electrodes YB and YB′ at the periphery of the scan/sustain electrode line Y, thereby preventing a voltage drop of the scan/sustain electrode line Y and lowered discharge voltage easily wall charges at the discharge cell.  
         [0080]    The PDP according to the second embodiment may further include second barrier ribs  58  formed in parallel to the first and second common sustain electrode lines Z and Z′ like the first embodiment. Since a driving waveform and an operation process in the second embodiment are identical to those in the first embodiment, an explanation as to them is omitted.  
         [0081]    [0081]FIG. 12 is a plan view showing an electrode arrangement of a plasma display panel (PDP) according to a third embodiment of the present invention.  
         [0082]    Referring to FIG. 12, the PDP according to the third embodiment includes address electrode lines X, first and second common sustain electrode lines Z and Z′ formed in a direction crossing the address electrode lines X, and first and second scan/sustain electrode lines Y and Y′ provided between the first and second common sustain electrode lines Z and Z′.  
         [0083]    A discharge cell  50  is positioned at each intersection among the first scan/sustain electrode line Y, the second scan/sustain electrode lines Y′, the first common sustain electrode lines Z and the second common sustain electrode lines Z′. The first and second scan/sustain electrode lines Y and Y′ and the first and second common sustain electrode liens Z and Z′ are transparent electrodes made from indium-tin-oxide (ITO). Since the ITO has a high resistance value, the rear sides of the first and second scan/sustain electrode lines Y and Y′ and the first and second common sustain electrode lines Z and Z′ are provided with bus electrodes YB, YB′, ZB and ZB′, respectively such that a uniform voltage can be applied to all the discharge cells  50 .  
         [0084]    Barrier ribs  52  are formed in parallel to the address electrode lines X. The first and second scan/sustain electrodes Y and Y′ are positioned at the center of the discharge cell  50 . The first and second common sustain electrode lines Z and Z′ are positioned at the periphery of the discharge cell  50  with having the first and second scan/sustain electrode lines Y and Y′ therebetween. Please note that, although a single scan/sustain electrode line Y have been provided at the center of the discharge cell in the first embodiment, two scan/sustain electrode lines Y and Y′ are provided at the center of the discharge cell  50  in the third embodiment.  
         [0085]    If a single scan/sustain electrode line Y is provided at the center of the discharge cell  50  like the first embodiment, then any one of the common electrode lines Z and Z′ first generates a discharge with respect to the scan/sustain electrode line Y in the sustain period and this discharge is unstable. However, if two scan/sustain electrode lines Y and Y′ are provided at the center of the discharge cell  50  like the third embodiment, then a sustain discharge is generated between the first common sustain electrode line Z and the first scan/sustain electrode line Y in the sustain period. Also, a sustain discharge is generated between the second common sustain electrode line Z′ and the second scan/sustain electrode line Y′ in the sustain period. The PDP according to the third embodiment can generate a stable sustain discharge within the discharge cell  50 .  
         [0086]    The PDP according to the third embodiment may further include second barrier ribs  58  formed in parallel to the first and second common sustain electrode lines Z and Z′ as shown in FIG. 13. Since a driving waveform and an operation process in the third embodiment are identical to those in the first embodiment, an explanation as to them is omitted.  
         [0087]    [0087]FIG. 14 shows a driving apparatus for the PDP of FIG. 12. Referring to FIG. 14, a driving apparatus for the PDP according to the third embodiment of the present invention includes a scan/sustain driver  60  for driving the first and second scan/sustain electrode lines Y and Y′, and a common sustaining driver  62  for driving the first and second common sustain electrode lines Z and Z′. The scan/sustain driver  60  applies a scanning pulse sequentially and a sustaining pulse to the first and second scan/sustain electrode lines Y and Y′. At this time, the first and second scan/sustain electrode lines Y and Y′ receive the same driving waveform from the scan/sustain driver  60 .  
         [0088]    The common sustaining driver  62  applies a sustaining pulse to the first and second common sustain electrode lines Z and Z′. The address electrode lines X receive a picture data synchronized with the scanning pulse from an address driver (not shown).  
         [0089]    In the sustain period, sustaining pulses Vsus having the same pulse width and voltage are alternately applied to the first and second scan/sustain electrode lines Y and Y′ and the first and second common sustain electrode lines Z and Z′. If the sustaining pulses Vsus are alternately applied, then a sustain discharge is generated between the first common sustain electrode line Z and the first scan/sustain electrode line Y while being generated between the second common sustain electrode line Z′ and the second scan/sustain electrode line Y′ as shown in FIG. 15.  
         [0090]    In other words, a sustain discharge is generated between the first and second scan/sustain electrode lines Y and Y′ provided at the center of the discharge cell and the first and second common sustain electrode line Z and Z′ provided at the periphery of the discharge cell  50 , respectively, so that the discharge can be efficiently utilized. Further, each discharge cell  50  is provided with four sustain electrodes Y. Y′, Z and Z′, so that a stable sustain discharge can be obtained.  
         [0091]    In the first to third embodiments of the present invention as described above, the electrodes provided at the center of the discharge cell  50  have been used as the scan/sustain electrode lines Y and Y′ and the electrodes provided at the periphery of the discharge cell  50  has been used as the common sustain electrode lines Z and Z′. Otherwise, the electrodes provided at the center of the discharge cell  50  may be used as the common sustain electrode lines Z and Z′ and the electrodes provided at the periphery of the discharge cell  50  may be used as the scan/sustain electrode lines Y and Y′, like a fourth embodiment as shown in FIG. 16.  
         [0092]    [0092]FIG. 17 shows a discharge cell of a PDP according to a fifth embodiment of the present invention, which has a structure of adding floating electrodes  68  and  69 . FIG. 17 represents a state of rotating an upper substrate by 90° with respect to a lower substrate so as to show up the entire electrode structure within one discharge cell.  
         [0093]    Referring to FIG. 17, the PDP according to the fifth embodiment includes first and second trigger electrodes  64 Y and  64 Z provided on an upper dielectric layer  72  in such a manner to be positioned at the center of a discharge cell, first and second sustain electrodes  66 Y and  66 Z provided on the upper dielectric layer  72  in such a manner to be positioned at the edge of the discharge cell, first and second floating electrodes  68  and  69  provided at the rear side of the upper dielectric layer  72 , and an address electrode  76 X provided at a lower dielectric layer  78  in a direction crossing the first and second sustain electrodes  66 Y and  66 Z. Barrier ribs  74  are provided between the upper dielectric layer  72  and the lower dielectric layer  78 , and a fluorescent layer  70  is coated on the surfaces of the lower dielectric layer  78  and the barrier ribs  74 .  
         [0094]    The trigger electrodes  64 Y and  64 Z spaced at a small distance at the center of the discharge cell is supplied with an alternating current pulse in the sustain period to thereby initiate a sustain discharge. The first and second sustain electrodes  66 Y and  66 Z spaced at a large distance at the edge of the discharge are used to keep a plasma discharge after said discharge was initiated by the trigger electrodes  64 Y and  64 Z. The address electrode  76 X plays a role to receive a data pulse in the address period to thereby cause an address discharge with respect to the first trigger electrode  64 Y supplied with a scanning pulse.  
         [0095]    The floating electrodes  68  and  69  are arranged in parallel to the first and second sustain electrodes  66 Y and  66 Z, and have smaller width than the first and second sustain electrodes  66 Y and  66 Z. The floating electrodes  68  and  69  prevent a crosstalk from being generated between the adjacent discharge cells. This will be described with reference to FIG. 18 below.  
         [0096]    In the sustain period, an alternating current pulse is alternately applied to the first and second sustain electrodes  66 Y and  66 Z. When a desired level of alternating current pulse is applied to the first sustain electrode  66 Y, a voltage equal to a half voltage of the alternating current pulse applied to the first sustain electrode  66 Y is derived into the floating electrode  68  provided under the first sustain electrode  66 Y.  
         [0097]    Accordingly, an erroneous discharge against the second sustain electrode  67 Z formed adjacently with having the barrier rib  74  therebetween can be prevented. In other words, a floating electrode  80  formed adjacently with having the barrier rib  74  remains at a higher level than a ground potential applied to the second sustain electrode  67 Z. As a result, a low voltage difference is generated between the floating electrodes  68  and  80 , so that an erroneous discharge between the floating electrodes  68  and  80  can be prevented.  
         [0098]    Further, when a desired voltage level of alternating current pulse is applied to the second sustain electrode  66 Z, a voltage equal to a half voltage of the alternating current pulse applied to the second sustain electrode  66 Z is derived into the floating electrode  69  provided under the second sustain electrode  66 Z. Accordingly, an erroneous discharge between the floating electrodes  69  and  82  formed adjacently with having the barrier rib  74  therebetween can be prevented. Such a fifth embodiment is applicable to the first and fourth embodiments of the present invention.  
         [0099]    As described above, according to the present invention, a sustain discharge is generated between at least one of first electrode provided at the center of the discharge cell and two second electrodes provided at the periphery of the discharge cell, so that the discharge space can be efficiently utilized. In other words, a sustain discharge is generated between the first electrode and the second electrode to thereby cause a sustain discharge having a long discharge path. Furthermore, two second electrodes are provided at the periphery of the discharge cell with having the first electrode therebetween, so that a crosstalk between the discharge cells can be prevented. Also, the barrier ribs are additionally provided in parallel to the first and second electrodes, so that a crosstalk between the discharge cells located at the upper and lower portions can be prevented.  
         [0100]    Moreover, the floating electrodes are provided under the second electrode provided at the periphery of the discharge cell, so that a crosstalk between the adjacent discharge cells cane be prevented.  
         [0101]    Although the present invention has been explained by the embodiments shown in the drawings described above, it should be understood to the ordinary skilled person in the art that the invention is not limited to the embodiments, but rather that various changes or modifications thereof are possible without departing from the spirit of the invention. Accordingly, the scope of the invention shall be determined only by the appended claims and their equivalents.