Abstract:
A plasma display panel configuration helps to prevent unwanted discharge generation in cells adjacent to excited discharge cells and to improve picture quality of the plasma display panel. An exemplary embodiment of the present invention includes barrier ribs for partitioning off discharge cells, wherein edge parts of the cross sectional shape of the barrier ribs are lower than central parts of the cross sectional shape of the barrier ribs and can have a number of distinctive shapes.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a plasma display panel, and more particularly to a plasma display panel that is adaptive for preventing mis-discharge from being generated in adjacent cells in driving the PDP and for improving picture quality. 
   2. Description of the Related Art 
   Recently, there have been developed various flat display panels that can reduce their weight and bulk, which was the disadvantage of a cathode ray tube CRT. Such flat display panels include liquid crystal displays LCD, field emission displays FED, plasma display panels PDP, electro-luminescence EL display device and so on. 
   The PDP among these display devices takes advantage of gas discharge and has an advantage of being made into a large-dimensioned panel easily. A three-electrode AC surface discharge PDP is a typical PDP, which includes three electrodes as shown in  FIG. 1  and is driven with AC voltage. 
   Referring to  FIG. 1 , a discharge cell of a three-electrode AC surface discharge PDP in the related art includes a first electrode  12 Y and a second electrode  12 Z formed on an upper substrate  10 , and an address electrode  20 X formed on a lower substrate  18 . 
   The first and second electrodes  12 Y and  12 Z are formed of a transparent material in order to transmit the light supplied from the discharge cell. There are formed bus electrodes  13 Y and  13 Z of a metal material in parallel to and on the rear surface of the first and second electrodes  12 Y and  12 Z. Such bus electrodes  13 Y and  13 Z are used to supply driving signals to the first and second electrodes  12 Y and  12 Z that have high resistance. 
   There are formed an upper dielectric layer  14  and a passivation film  16  on the upper substrate  10  provided with the first and second electrodes  12 Y and  12 Z. On the upper dielectric layer  14 , there are formed wall charges generated upon plasma discharge. The passivation film  16  prevents the damage of the upper dielectric layer  14  by the sputtering generated upon the plasma discharge, and at the same time, increase the emission efficiency of secondary electrons. The passivation film  16  is usually magnesium oxide MgO. 
   There are formed a lower dielectric layer  22  and barrier ribs  24  on the lower substrate  18  provided with the address electrode  20 X, and the surface of the lower dielectric layer  22  and the barrier ribs  24  is coated with a phosphorus  26 . The address electrode  20 X is formed crossing the first and second electrode  12 Y and  12 Z. The barrier ribs  24  are formed parallel to the address electrode  20 X to prevent an ultraviolet ray and a visible ray from leaking out to adjacent discharge cells, wherein the ultraviolet ray and the visible ray are generated by discharge. 
   The phosphorus  26  is excited by the ultraviolet ray generated upon the plasma discharge to generate any one of red, green and blue visible rays. There is injected an inert mixture gas such as He+Ne, He+Xe or He+Ne+Xe for the gas discharge in a discharge space provided between the upper/lower substrates and barrier ribs. 
   In the related art PDP, the first and second electrodes are formed opposite to each other in each discharge cell as in  FIG. 2 . The first electrode  12 Y is supplied with reset pulses, scan pulses and first sustain pulses. The second electrode  12 Z is supplied with second sustain pulses. 
   The discharge cells are initialized when the reset pulse is applied to the first electrode  12 Y. The address electrode  20 X is supplied with data pulses synchronized with the scan pulses when the scan pulses are applied to the first electrode  12 Y. At this moment, there occur the address discharges in the discharge cells supplied with the scan pulses and the data pulses. 
   The first and second sustain pulses are alternately applied to the first and second electrodes  12 Y and  12 Z after the address discharges being generated in the discharge cells. If the first and second sustain pulses are applied to the first electrode  12 Y and the second electrode  12 Z, there is generated sustain discharges in the discharge cells where the address discharges were generated. The discharge time of the sustain discharge is determined by a gray level value, and accordingly a picture is displayed in accordance with gray level values. 
   On the other hand, in the related art PDP, the first and second electrodes  12 Y and  12 Z are formed opposite to each other with wide areas in each of the discharge cells. In this way, if the first and second electrodes  12 Y and  12 Z are wide in area, a lot of power is dissipated, and accordingly the discharge efficiency of the PDP is deteriorated. In order to overcome such a disadvantage, there has been suggested a PDP as in  FIG. 3 . 
   Referring to  FIG. 3 , a PDP according to another embodiment of the related art has a delta type structure where discharge cells located adjacent to each other on the upward/downward each make up one pixel. In other words, in the PDP according to the embodiment of the related art, an R sub-pixel and a B sub-pixel located in the n th  (n is a natural number over 1) line and a G sub-pixel located in the (n+1) th  or (n−1) th  line make up one pixel. 
   The PDP according to the embodiment of the related art includes an address electrode  40 X, a first and a second electrode  32 Y,  32 Z formed crossing the address electrode  40 X, and a first and a second bus electrode  33 Y,  33 Z formed on the first and second electrodes  32 Y and  32 Z. 
   The first and second electrodes  32 Y,  32 Z include a first and a second main electrode  32 A,  32 C formed in a perpendicular direction to the address electrode  40 X, and a first and a second auxiliary electrode  32 B,  32 D extended from the first and second main electrodes  32 A,  32 C in the same direction as the address electrode  40 X. 
   The first auxiliary electrode  32 B is formed on both sides of the first main electrode  32 A, and the second auxiliary electrode  32 D is formed on both sides of the second main electrode  32 C in the same way as the first auxiliary electrode  32 B. 
   The address electrode  40 X includes an address main electrode  40 A formed in a line crossing the first and second main electrodes  32 A,  32 C, and an address auxiliary electrode  40 B extended by a designated width in a direction of crossing the address main electrode  40 A within a discharge cell that makes up one pixel. 
   Further, on the upper surface of the POP according to another embodiment of the related art, there are the second auxiliary electrodes  32 B alternately extended from the first main electrode  32 A, and a first dielectric layer  44 B that the upper dielectric layer and the protective film are sequentially deposited on the entire upper plate to cover the second auxiliary electrode  32 B. 
   The wall charges generated upon the plasma discharge are accumulated through the upper dielectric layer on the first dielectric layer  44 B, which prevents the damage of itself caused by the sputtering generated upon the plasma discharge by way of the passivation film and at the same time increases the emission efficiency of the secondary electrons. 
   On the lower surface of the PDP, there are formed a first to a third address electrode  42 A,  42 B,  42 C crossing the first and second electrodes  32 Y and  32 Z, a second dielectric layer  44   a  on the entire lower plate to cover the address electrodes  42 A,  42 B,  42 C, and horizontal barrier ribs  46 B on the lower surface in the same direction as the first to third address electrodes  42 A,  42 B,  42 C. There is formed a phosphorus (not shown) on the surface of the second dielectric layer  44 A and the horizontal barrier ribs  46 B. The first and third address electrodes  42 A,  42 C formed on both sides among the first to third address electrodes  42 A,  42 B,  42 C are the address auxiliary electrode  40 B extended from the address main electrode  40 A to the direction of the first and second electrodes  32 Y,  32 Z, and the second address electrode  42 B is the address electrode main electrode  40 A. The barrier ribs  46 B are formed parallel to the first to third address electrodes  42 A,  42 B,  42 C to prevent the ultraviolet ray and the visible ray generated by the discharge from leaking out to the adjacent discharge cells. 
   In the PDP according to the embodiment of the related art, the upper part of the barrier ribs  46  has a rectangular shape. 
     FIGS. 5 to 12  are views representing equipotential surfaces when a specific voltage is applied to a discharge cell according to the POP shown in  FIG. 4 . 
   Referring to  FIGS. 5 to 12 , the width of the second auxiliary electrodes  32 B formed on the upper plate of the PDP is 185 μm, the width of the first and second address electrodes  42 A,  42 C formed on both sides of the lower plate is 150 μm. 70 μm is the width of the second address electrode  42 B, which is formed between the first and third address electrodes  42 A,  42 C and where the address auxiliary electrode  40 B is not formed. 120 μm is the height of the horizontal barrier ribs  46 B formed being closed on the lower plate, and the dielectric constant of the horizontal barrier ribs  46 B is  12 . At this moment, the second auxiliary electrodes  32 B consist of a first-second auxiliary electrode  32 B 1  formed on its left on the basis of the horizontal barrier ribs  46 B, and a second—second auxiliary electrode  32 B 2  formed on its right. 
   Further, in  FIGS. 5 to 12 , if the voltage applied is 0V, no voltage is applied, 1V means that a designated voltage is applied, and −1.2V means that a reverse voltage is applied and the absolute value of the voltage is higher than 1V. 
   Referring to  FIGS. 5 to 7 , the first-second auxiliary electrode  32 B 1  and the first and third address electrodes  42 A and  42 C of the PDP are supplied with 0V, i.e., no voltage is applied, and a voltage of 1V is applied only to the second address electrode  42 B. At this moment, the discharge cell including the first and third address electrode  42 A and  42 C is a turned-off cell (hereinafter, off-cell), if such an off-cell is turned on, it is considered that there occurs mis-discharge. 
   Comparing  FIG. 5  with  FIG. 6 , if the second address electrode  42 B is supplied with a data voltage, the maximum electric field (the maximum electric field is formed between the upper part of the barrier ribs  66  and the first dielectric layer) of the off-cell including the first and third address electrodes  42 A,  42 C has a higher value in the event of  FIG. 6  (Emax=1.55E-2) where an air gap exists between the horizontal barrier ribs  46 B and the first dielectric layer  44 B than in the event of  FIG. 5  (Emax=8.8E-3) where an air gap does not exist. Hereby, there is a higher probability in mis-discharge in the event that there is the air gap between the horizontal barrier ribs  46 B and the first dielectric layer  44 B. 
     FIG. 7  represents the case that the air gap is big between the horizontal barrier ribs  46 B and the first dielectric layer  44 B. At this moment, the maximum electric field of the off-cell in  FIG. 7  (Emax=1.48E-2) is not changed much when comparing with  FIG. 6  (Emax=1.55E-2). In  FIG. 7 , the direction of the electric field is a perpendicular direction to the equipotential surfaces formed between the horizontal barrier ribs  46 B and the first dielectric layer  44 A. In this case, the electric field in the air gap (I) causes charged particles to move upward or downward in accordance with their polarity. 
   Referring to  FIGS. 6 and 7 , the first-second auxiliary electrode  32 B 1 , the second-second auxiliary electrode  32 B 2  and the third address electrode  42 C of the PDP are supplied with 0V, i.e., no voltage is applied, and a data voltage of 1V is applied to the first and second address electrodes  42 A and  42 B,  FIG. 6  represents the case that there is no air gap between the horizontal barrier ribs  46 B and the first dielectric layer  44 B, and  FIG. 7  represents the case that there is air gap between the horizontal barrier ribs  46 B and the first dielectric layer  44 B. 
   When comparing the strength of the maximum electric field induced to the off-cell including the third address electrode  42 C in  FIG. 6  with that in  FIG. 7 , as can be seen in  FIGS. 3 and 4 , the strength of the electric field is higher in  FIG. 7 , i.e., when there is air gap (Emax=1.48E-2), than when there is no air gap (Emax=8.85E-3). 
   Referring to  FIGS. 8 and 9 , the first-second auxiliary electrode  32 B 1 , the second-second auxiliary electrode  32 B 2  and the third address electrode  42 C of the PDP are supplied with 0V, i.e., no voltage is applied, and a data voltage of 1V is applied to the first and second address electrodes  42 A and  42 B.  FIG. 8  represents equipotential surfaces when there is no air gap between the horizontal barrier ribs  46 B and the first dielectric layer  44 B, and about 9.02E-3 is the strength of the maximum electric field Emax induced to the off-cell that includes the third address electrode  42 C.  FIG. 9  represents equipotential surfaces when 25 μm is the air gap between the horizontal barrier ribs  46 B and the first dielectric layer  44 B, and about 1.52E-2 is the strength of the maximum electric field Emax induced to the off-cell that includes the third address electrode  42 C. 
   Referring to  FIG. 10 , the first-second auxiliary electrode  32 B 1 , the second-second auxiliary electrode  32 B 2  and the second and third address electrodes  42 B,  42 C of the PDP are supplied with 0V, i.e., no voltage is applied, and a data voltage of 1V is applied only to the first address electrode  42 A. In this case,  FIG. 10  represents equipotential surfaces when there is no air gap between the horizontal barrier ribs  46 B and the first dielectric layer  44 B, and about 9.4E-3 is the strength of the maximum electric field Emax induced to the off-cell that includes the third address electrode  42 C. 
   As can be seen in  FIGS. 5 to 9 , the presence or absence of the air gap between the horizontal barrier ribs  46 B and the first dielectric layer  44 B is an important factor with respect to the mis-discharge. In other words, the strength of the maximum electric field is high when there is the air gap. Further, it can be seen through  FIGS. 6 and 7  that the strength of the maximum electric field in the vicinity of the air gap is not much changed in accordance with the size of the air gap. 
   When observing though  FIGS. 6 ,  7  and  9 , cross talks occur because the voltage applied to the second address electrode  42 B located at the lower part of the horizontal barrier ribs  46 B forms a strong electric field in the vicinity of the air gap within the discharge cell if there is the air gap between the horizontal barrier ribs  46 B and the first dielectric layer  44 B. Comparing  FIG. 8  with  FIG. 10 , there is generated no cross talk when 0V voltage is applied to the second address electrode  42 B formed at the lower part of the horizontal barrier ribs  46 B. 
     FIG. 11  represents equipotential surfaces when a specific voltage is applied to a discharge cell in accordance with the related art. 
   Referring to  FIG. 11 , the first-second auxiliary electrode  32 B 1 , the second—second auxiliary electrode  32 B 2  of the POP are supplied with −1.2V voltage, the third address electrode  42 C are supplied with 0V, and a data voltage of 1V is applied to the first and second address electrode  42 A,  42 B. In this case, the discharge cell including the first address electrode  42 A is turned on (hereinafter, on-cell), and the cell including the third address electrode  42 C is the off-cell because the data voltage is not applied. Further,  FIG. 11  represents equipotential surfaces when 5 μm is the air gap between the horizontal barrier ribs  46 B and the first dielectric layer  44 B. 
     FIG. 12  is a diagram representing the relative strength of the electric field formed within the right and left discharge cells. 
   Referring to  FIG. 12 , the strength of the maximum electric field in the off-cell including the third address electrode  42 C in the PDP appears to be almost the same as the strength of the maximum electric field of the discharge cells where the data voltage is applied to the first address electrode  42 A when there is the air gap between the horizontal barrier ribs  46 B and the first dielectric layer  44 B as shown in  FIG. 11 , and the upper part of the horizontal barrier ribs  46 B has a rectangular shape. In this case, there is a higher probability of the off-cell being turned on, i.e., a strong electric field is formed around the peripheral air gap due to the pulse applied to the column electrode of the peripheral off-cell to cause undesired discharge to be generated, thus a picture quality is deteriorated. 
   SUMMARY OF THE INVENTION 
   Accordingly, it is an object of the present invention to provide a plasma display panel that is adaptive for preventing mis-discharge from being generated in adjacent cells in driving the PDP. 
   It is another object of the present invention to provide a plasma display panel that is adaptive for reducing crosstalk. 
   In order to achieve these and other objects of the invention, a plasma display panel according to an aspect of the present invention includes a characteristic that edge parts of the barrier ribs are lower than central parts of the barrier ribs. 
   The discharge cells include red, green and blue discharge cells, being arranged in a delta shape. 
   The barrier ribs include first barrier ribs; and second barrier ribs coupled with the first barrier ribs vertically. 
   Herein, at least parts of the barrier ribs have their upper end rounded. 
   Herein, at least parts of the barrier ribs have their upper end edge stepped. 
   Herein, at least parts of the barrier ribs have a concave upper end edge. 
   The plasma display panel further includes a plurality of first electrodes formed on a first substrate, a plurality of second electrodes formed on a second substrate opposite to the first substrate with a discharge space therebetween to cross the first electrodes; a first dielectric layer formed on the first substrate to cover the first electrodes; a passivation film formed on the first dielectric layer; a second passivation layer formed on the second substrate to cover the second electrodes; and a phosphorus formed on the second dielectric layer and the barrier ribs. 
   The first electrode includes a metal bus electrode; and a transparent electrode connected to the metal bus electrode and having its width wider than the metal bus electrode. 
   The transparent electrode includes a main electrode; and an auxiliary electrode extended from the main electrode toward the discharge cell, and wherein the auxiliary electrode is extended from both sides of the main electrode in a zigzag. 
   The second electrode includes a main electrode; and an auxiliary electrode extended from both sides of the main electrode and having at least part thereof overlap the first electrode. 
   The barrier ribs are formed in a stripe shape, and central parts thereof are convex. 
   The barrier ribs are formed in a stripe shape, and an upper end edge thereof is stepped. 
   A plasma display panel according to another aspect of the present invention includes a characteristic that a dielectric constant value is different in parts of the barrier ribs. 
   Herein, edge parts of the barrier ribs are lower than central parts of the barrier ribs. 
   The barrier ribs include first barrier ribs; and second barrier ribs coupled with the first barrier ribs vertically. 
   Herein, any one of the first and second barrier ribs has a dielectric constant value of its lower end less than that of its upper end. 
   The dielectric constant value of the lower end of any one of the first and second barrier ribs is less than 12, and a dielectric constant value of an area except for the lower end is 12 or more. 
   A plasma display panel according to still another aspect of the present invention includes a characteristic that upper ends of the barrier ribs are opposite to the a substrate with an air gap therebetween, and the air gap between upper end edges of the barrier ribs and the first substrate is different from the air gap between central parts of the barrier ribs and the first substrate. 
   Herein, a dielectric constant value is different in parts of the barrier ribs. 
   Herein, edge parts of the barrier ribs are lower than central parts of the barrier ribs. 
   A plasma display panel according to still another aspect of the present invention includes a characteristic that upper ends of the barrier ribs are opposite to a first substrate with an air gap therebetween, a dielectric constant value is different in parts of the barrier ribs, and edge parts of the barrier ribs are lower than central parts of the barrier ribs. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     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: 
       FIG. 1  is a perspective view representing a three-electrode AC surface discharge plasma display panel in the related art; 
       FIG. 2  is a diagram representing an electrode structure of the PDP shown in  FIG. 1 ; 
       FIG. 3  is a plan view representing an electrode structure of another PDP according to another embodiment in the related art; 
       FIG. 4  a sectional view of the PDP taken along the line “A–A′” of  FIG. 3 ; 
       FIGS. 5 to 11  are diagrams each representing equipotential surfaces when a specific voltage is applied to a discharge cell according to the related art; 
       FIG. 12  is a diagram representing a relative strength of an electric field formed within the right and left discharge cells when a data voltage is applied to an address electrode as in  FIG. 11 ; 
       FIG. 13  is a plan view representing an electrode structure of a plasma display panel according to the present invention; 
       FIG. 14  is a sectional view of the plasma display panel according to the first embodiment of the present invention, taken along the line “B–B′” of  FIG. 13 ; 
       FIG. 15  is a sectional view of the plasma display panel according to the second embodiment of the present invention, taken along the line “B–B′” of  FIG. 13 ; 
       FIG. 16  is a diagram representing a relative strength of an electric field formed within the right and left discharge cells when a data voltage is applied to an address electrode as in  FIG. 15 ; 
       FIG. 17  is a sectional view of the plasma display panel according to the third embodiment of the present invention, taken along the line “B–B′” of  FIG. 13 ; 
       FIG. 18  is a perspective view representing a lower plate structure of a PDP that has barrier ribs of stripe type, according to the fourth embodiment of the present invention; 
       FIG. 19A  is a sectional view representing barrier ribs of stripe type with their upper end round-shaped as shown in  FIG. 18 ; 
       FIG. 19B  is a sectional view representing barrier ribs of stripe type with their upper end stepped as shown in  FIG. 18 ; and 
       FIG. 19C  is a sectional view representing barrier ribs of stripe type with their upper end grooved as shown in  FIG. 18 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   With reference to  FIGS. 13 to 19C , embodiments of the present invention will be explained as follows. 
   Referring to  FIG. 13 , a plasma display panel PDP according to an embodiment of the present invention has a delta type structure where discharge cells located adjacent to each other on the upward/downward each make up one pixel. In other words, in the PDP according to the embodiment of the present invention, an R sub-pixel and a B sub-pixel located in the n th  (n is a natural number over 1) line and a G sub-pixel located in the (n+1) th  or (n−1) th  line make up one pixel. 
   The PDP according to the embodiment of the present invention includes an address electrode  60 X on a lower plate, a first and a second electrode  52 Y,  52 Z formed on un upper plate crossing the address electrode  60 X, and a first and a second bus electrode  53 Y,  53 Z formed on the first and second electrodes  52 Y and  52 Z. 
   The first and second electrodes  52 Y,  52 Z include a first and a second main electrode  52 A,  52 C formed in a perpendicular direction to the address electrode  60 X, and a first and a second auxiliary electrode  52 B,  52 D extended from the first and second main electrodes  52 A,  52 C. 
   The first auxiliary electrode  52 B is formed in turn or in a zigzag on both sides of the first main electrode  52 A. In other words, if the first auxiliary electrode  62 B crossing the n th  address electrode  60 X is extended from the first side of the first main electrode  62 A, the first auxiliary electrode  52 B crossing the (n+1) th  address electrode  60 X is extended from the second side of the first main electrode  52 A. 
   The second auxiliary electrode  52 D is formed in turn on the first and second sides of the second main electrode  52 C in the same way as the first auxiliary electrode  52 B. At this moment, the second main electrode  52 C is formed opposite to the first main electrode  52 A. In other words, if the first auxiliary electrode  52 B crossing the n th  address electrode  60 X is extended from the first side of the first main electrode  52 A, the second auxiliary electrode  52 D crossing the n th  address electrode  60 X is extended from the second side of the second main electrode  52 C. 
   The address electrode  60 X includes an address main electrode  60 A formed in a line crossing the first and second main electrodes  52 A,  52 C, and an address auxiliary electrode  60 B extended by a designated width in a direction of crossing the address main electrode  60 A within a discharge cell that makes up one pixel. 
   Further, on the upper surface of the PDP according to the first embodiment of the present invention, there are the second auxiliary electrodes  52 B alternately extended from the first main electrode  52 A, and a first dielectric layer  64 B that the upper dielectric layer and the protective film are sequentially deposited on the entire upper plate to cover the second auxiliary electrode  52 B. 
   The wall charges generated upon the plasma discharge are accumulated through the upper dielectric layer on the first dielectric layer  64 B, which prevents the damage of itself caused by the sputtering generated upon the plasma discharge by way of the passivation film and at the same time increases the emission efficiency of the secondary electrons. 
   On the lower surface of the PDP, there are formed a first to a third address electrode  62 A,  62 B,  62 C crossing the first and second electrodes  52 Y and  52 Z, a second dielectric layer  64 A on the entire lower plate to cover the address electrodes  62 A,  62 B,  62 C, and barrier ribs  66  to partition off discharge cells. 
   There is formed a phosphorus (not shown) on the surface of the second dielectric layer  64 A and the horizontal barrier ribs  66 B. The first and third address electrodes  62 A,  62 C formed on both sides among the first to third address electrodes  62 A,  62 B,  62 C are the address auxiliary electrode  60 B extended from the address main electrode  60 A to the direction of the first and second electrodes  52 Y,  52 Z, and the second address electrode  62 B is the address electrode main electrode  60 A. 
   The barrier ribs  66  includes vertical barrier ribs  66 A and horizontal barrier ribs  66 B connected to the vertical barrier ribs  66 A vertically. The vertical barrier ribs  66 A are formed crossing the first to third address electrodes  62 A,  62 B and  62 C, and the horizontal barrier ribs  66 B are formed parallel to the first to third address electrodes  62 A,  62 B,  62 C, with their upper end rounded. At this moment, the horizontal barrier ribs  66 B is formed with their upper end rounded and their central area convex. Hereby, the edge of the horizontal barrier ribs  668  is lower than the central area of the horizontal barrier ribs  66 B. 
   The upper end of the barrier ribs  66  is opposite to the upper plate having an air gap therebetween. Accordingly, the air gap between the upper end edge of the horizontal barrier ribs  66 B and the upper plate is different from the air gap between the upper end central area of the horizontal barrier ribs  66 B and the upper plate. 
   On the other hand, on the upper surface of the PDP according to the second embodiment of the present invention, as shown in  FIG. 15 , there are the second auxiliary electrodes  52 B alternately extended from the first main electrode  52 A, and a first dielectric layer  64 B that the upper dielectric layer and the protective film are sequentially deposited on the entire upper plate to cover the second auxiliary electrode  52 B. The wall charges generated upon the plasma discharge are accumulated through the upper dielectric layer on the first dielectric layer  64 B, which prevents the damage of itself caused by the sputtering generated upon the plasma discharge by way of the passivation film and at the same time increases the emission efficiency of the secondary electrons. 
   On the lower surface of the PDP, there are formed a first to a third address electrode  62 A,  62 B,  62 C crossing the first and second electrodes  52 Y and  52 Z, a second dielectric layer  64 A on the entire lower plate to cover the address electrodes  62 A,  62 B,  62 C, and barrier ribs  66  to partition off discharge cells. 
   There is formed a phosphorus (not shown) on the surface of the second dielectric layer  64 A and the horizontal barrier ribs  66 B. The first and third address electrodes  62 A,  62 C formed on both sides among the first to third address electrodes  62 A,  62 B,  62 C are the address auxiliary electrode  60 B extended from the address main electrode  60 A to the direction of the first and second electrodes  52 Y,  52 Z, and the second address electrode  62 B is the address electrode main electrode  60 A. 
   The barrier ribs  66  includes vertical barrier ribs  66 A and horizontal barrier ribs  66 B connected to the vertical barrier ribs  66 A vertically. The vertical barrier ribs  66 A are formed crossing the first to third address electrodes  62 A,  62 B and  62 C, and the horizontal barrier ribs  66 B are formed parallel to the first to third address electrodes  62 A,  62 B,  62 C, with their upper end edge stepped or chamfered by the about 20 μm. At this moment, the horizontal barrier ribs  66 B is formed with their upper end edge stepped. Such barrier ribs  66  prevent the ultraviolet ray and the visible ray generated by the discharge from leaking out to the adjacent discharge cells. At this moment, the area, which is needed to be stepped or chamfered, is the area of the barrier ribs where the barrier ribs is perpendicular to the address electrode. Owing to this, the edge of the horizontal barrier ribs  66 B is lower than the central area of the horizontal barrier ribs  66 B. 
   The upper end of the barrier ribs  66  is opposite to the upper plate having an air gap therebetween. Accordingly, the air gap between the upper end edge of the horizontal barrier ribs  66 B and the upper plate is different from the air gap between the upper end central area of the horizontal barrier ribs  66 B and the upper plate. 
     FIG. 16  is a diagram representing a relative strength of an electric field formed within the right and left discharge cells when a data voltage is applied to an address electrode in the event that there is a barrier rib structure as in  FIGS. 14 and 15 . 
   Firstly, the width of the second auxiliary electrodes  52 B formed on the upper plate of the PDP shown in  FIGS. 14 and 15  is 185 μm, the width of the first and third address electrodes  62 A,  62 C formed on both sides of the lower plate is 150 μm. 70 μm is the width of the second address electrode  62 B, which is formed between the first and third address electrodes  62 A,  62 C and where the address auxiliary electrode  60 B is not formed. 120 μm is the height of the barrier ribs  66  formed being closed on the lower plate, and the dielectric constant of the barrier ribs  66  is 12. Further, 30 μm is the first and second dielectric layers  64  formed on each electrode of the upper plate and the lower plate. At this moment, the second auxiliary electrodes  52 B consist of a first-second auxiliary electrode  52 B 1  formed on its left on the basis of the horizontal barrier ribs  66 , and a second-second auxiliary electrode  52 B 2  formed on its right. The air gap between the horizontal barrier ribs  66 B and the first dielectric layer  64 B is about 5 μm. 
   Further, the first-second auxiliary electrode  52 B 1  and the second—second auxiliary electrode  52 B 2  are supplied with a voltage of −1.2, the third address electrode  62 C is supplied with 0V, and the first and the second address electrodes  62 B,  62 C are supplied with a data voltage of 1V. In this case, the discharge cell including the first address electrode  62 B is the cell turned on (hereinafter, on-cell), and the cell including the third address electrode  62 C is the cell turned off (hereinafter, off-cell) because the data voltage is not applied. 
   In this case, the strength of the maximum electric field of the cell including the third address electrode  62 C, i.e., the off-cell, is far less than the strength of the maximum electric field Emax of the cell including the first address electrode  62 A, i.e., the on-cell, (reduced down to about ½). Hereby, the mis-discharge with the adjacent cell can be prevented. In other words, the upper end of the horizontal barrier ribs  66 B are formed in a rounded shape or a stepped/chamfered shape, thus the strength of the maximum electric field of the on-cell is made weak to be able to weaken the electric field concentrated distribution. 
   On the other hand, on the upper surface of the PDP according to the third embodiment of the present invention, as shown in  FIG. 17 , there are the second auxiliary electrodes  52 B alternately extended from the first main electrode  52 A, and a first dielectric layer  64 B that the upper dielectric layer and the protective film are sequentially deposited on the entire upper plate to cover the second auxiliary electrode  52 B. The wall charges generated upon the plasma discharge are accumulated through the upper dielectric layer on the first dielectric layer  64 B, which prevents the damage of itself caused by the sputtering generated upon the plasma discharge by way of the passivation film and at the same time increases the emission efficiency of the secondary electrons. 
   On the lower surface of the PDP, there are formed a first to a third address electrode  62 A,  62 B,  62 C crossing the first and second electrodes  52 Y and  52 Z, a second dielectric layer  64 A on the entire lower plate to cover the address electrodes  62 A,  62 B,  62 C, and barrier ribs  66  to partition off discharge cells. 
   There is formed a phosphorus (not shown) on the surface of the second dielectric layer  64 A and the horizontal barrier ribs  66 B, The first and third address electrodes  62 A,  62 C formed on both sides among the first to third address electrodes  62 A,  62 B,  62 C are the address auxiliary electrode  60 B extended from the address main electrode  60 A to the direction of the first and second electrodes  52 Y,  52 Z, and the second address electrode  62 B is the address electrode main electrode  60 A. 
   The barrier ribs  66  includes vertical barrier ribs  66 A and horizontal barrier ribs  66 B connected to the vertical barrier ribs  66 A vertically. The vertical barrier ribs  66 A are formed crossing the first to third address electrodes  62 A,  62 B and  62 C, and the horizontal barrier ribs  66 B are formed parallel to the first to third address electrodes  62 A,  62 B,  62 C. 
   In the horizontal barrier ribs  66 B in the present invention, the lower end thereof adjacent to the second address electrode  62 B and the other area except for the lower end each have a different dielectric constant. In other words, the lower end of the horizontal barrier ribs  66 B is made up of a material with a low dielectric constant as compared with the upper end thereof. In  FIG. 17 , the dielectric constant of the lower end of the horizontal barrier ribs  66 B is 12 or less (e.g., the dielectric constant of air=1), and the dielectric constant of the area except for the lower end of the horizontal barrier ribs, i.e., the upper end, is 12 or more, At this moment, the dielectric constant of the horizontal barrier ribs  66 B is lower than the dielectric constant of the vertical barrier ribs  66 A, i.e., the dielectric constant of 12. 
   Accordingly, all the voltage applied to the second address electrode  62 B is almost applied in the area that is made up of the material with the low dielectric constant. It is shown in black around the second address electrode  62 B in  FIG. 17 . That is, it represents that equipotential surfaces are concentrated around the second address electrode  62 B and that the strength of the electric field is strong around the second address electrode  62 B. Hereby, as in  FIG. 17 , the strength of the maximum electric field (Emax=8.85E-3) is shown to be lower as compared with the other cases, and the probability of generating mis-discharge with the adjacent discharge cell becomes lessened. 
   Further, as explained in  FIG. 17 , the discharge, which might be generated due to the pulse applied to column electrode of the neighboring discharge cell, can be prevented even in the event that the air gap is made within the lower end of the horizontal barrier ribs  66 B on the second address electrode  62 B, thereby improving a picture quality. 
   On the other hand, referring to  FIG. 18 , a PDP according to another embodiment of the present invention includes upper plate electrodes formed on an upper plate (not shown), an upper dielectric layer (not shown) formed on the upper plate to cover the upper plate electrodes, a passivation film (not shown) formed on the upper dielectric layer, address electrodes  160 X formed on a lower plate  150  opposite to the upper plate with a discharge space therebetween crossing the upper plate electrodes, a lower dielectric layer  164  formed on the lower plate to cover the address electrodes  160 X, barrier ribs  166  formed on and perpendicularly to the lower dielectric layer  164  to partition off discharge cells, and a phosphorus  126  formed on the lower dielectric layer  164  and the barrier ribs  166 . 
   The upper electrodes include a pair of sustain electrodes (not shown) formed parallel to the each other on the upper plate. The upper dielectric layer has wall charges accumulated upon plasma discharge, and a passivation film prevents the damage of the sustain electrode pair and the upper dielectric layer caused by the sputtering of gas ion upon the plasma discharge, thus lengthening the life-time of the PDP and acting to increase the emission efficiency of the secondary electron. 
   The address electrode  160 X of the lower plate  150  is formed crossing the sustain electrode pair. The address electrode  160 X is supplied with data signals in order to select cells to be displayed. 
   The barrier ribs  166  is a stripe type and formed parallel to the address electrode  160 X to prevent the ultraviolet ray generated by the discharge from leaking out to the adjacent discharge cells, thereby acting to prevent electrical optical crosstalk between the adjacent discharge cells. 
   The barrier ribs  166  are formed to have their upper end rounded as shown in  FIG. 19A . In other words, the barrier ribs  166  is formed to be round having their upper end central area convex. Due to this, the edge of the barrier ribs  166  is lower than the central area of the barrier ribs  166 . 
   The upper end of the barrier ribs  166  is opposite to the upper plate having an air gap therebetween. Accordingly, the air gap between the upper end edge of the barrier ribs  166  and the upper plate is different from the air gap between the upper end central area of the barrier ribs  166  and the upper plate. 
   The surface of the lower dielectric layer  164  and the barrier ribs  166  is coated with a phosphorus  126  to generate any one of red, green and blue visible rays. And, there is injected an inert mixture gas such as He+Xe, Ne+Xe, He+Xe+Ne for discharge into a gas discharge space provided between the upper plate, the lower plate  150  and the barrier ribs  166 . 
   On the other hand, in the PDP according to the embodiment of the present invention, the barrier ribs  166 , as shown in  FIG. 19B , have the peripheral area around the edge of the upper end formed to be stepped or chamfered by the about 20 μm. In other words, the barrier ribs  166  have their upper end edge stepped. Such barrier ribs  166  prevent the ultraviolet ray and the visible ray generated by the discharge from leaking out to the adjacent discharge cells. At this moment, the area, which is needed to be stepped or chamfered, is the area of the barrier ribs perpendicular to the address electrode. Because of this, the edge of the barrier ribs  166  is lower than the central are of the barrier ribs  166 . The upper end of the barrier ribs  166  is opposite to the upper plate having the air gap therebetween. Accordingly, the air gap between the upper end edge of the barrier ribs  166  and the upper plate is different from the air gap between the upper end central area of the barrier ribs  166  and the upper plate. 
   In this case, in the PDP according to the embodiment of the present invention, the upper end of the barrier ribs  166  is formed to be rounded or stepped/chamfered, thus the strength of the maximum electric field of the off-cell is far less than the strength of the maximum electric field Emax of the on-cell (reduced down to about ½). Hereby, the mis-discharge with the adjacent cell can be prevented. In other words, the upper end of the barrier ribs  166  are formed in a rounded shape or a stepped/chamfered shape, thus the strength of the maximum electric field of the on-cell is made weak to be able to weaken the electric field concentrated distribution. 
   On the other hand, in the PDP according to the embodiment of the present invention, the lower end of the barrier ribs  166  and the other area except for the lower end of the barrier ribs  166  each is formed to have a different dielectric constant. In other words, the lower end of the barrier ribs  166  is made up of a material with a low dielectric constant as compared with the upper end thereof. Because of this, the dielectric constant of the lower end of the barrier ribs  166  is 12 or less (e.g., the dielectric constant of air=1), and the dielectric constant of the area except for the lower end of the barrier ribs  166 , i.e., the upper end, is 12 or more. 
   Accordingly, all the voltage applied to the address electrode is almost applied in the area that is made up of the material with the low dielectric constant. Because of this, it represents that equipotential surfaces are concentrated around the address electrode and that the strength of the electric field is strong around the address electrode. Accordingly, the probability of generating mis-discharge with the adjacent discharge cell becomes lessened. 
   On the other hand, in the PDP according to the embodiment of the present invention, the barrier ribs  166  have a concave groove at their upper end as shown in  FIG. 19C . Such barrier ribs  166  prevent the ultraviolet ray and the visible ray generated by the discharge from leaking out to the adjacent cells, and increase its exhaustion rate. Due to this, the edge of the barrier ribs  166  is lower than the central area of the barrier ribs  166 . The upper end of the barrier ribs  166  is opposite to the upper plate with the air gap therebetween. Accordingly, the air gap between the upper end edge of the barrier ribs  166  and the upper plate becomes different from the air gap between the upper end central area of the barrier ribs  166  and the upper plate. 
   As described above, the plasma display panel according to the present invention has the upper end of the horizontal barrier ribs rounded or chamfered to prevent mis-discharge between the adjacent cells. 
   Further, the plasma display panel according to the present invention has the lower end of the horizontal barrier ribs near to the address electrode made up of a material with a low dielectric constant to prevent the crosstalk between the adjacent cells and to improve the picture quality. 
   Further, the plasma display panel according to the present invention has the air gap formed inside the lower part of the horizontal barrier ribs to prevent the mis-discharge, which is generated by the pulse applied to the electrode of the neighboring off-cell, and to improve the picture quality. 
   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.