Patent Publication Number: US-2010127623-A1

Title: Plasma display panel

Description:
CROSS REFERENCE TO THE RELATED APPLICATIONS 
     This application is a U.S. National Stage application claiming the benefit or prior filed International Application No. PCT/JP2007/000319, filed on Mar. 28, 2007, the entire contents of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a plasma display panel used for a display device. 
     BACKGROUND ART 
     A plasma display panel (PDP) is configured with two glass plates adhering to each other, and displays an image with discharge light emitted in a space formed between the glass plates. A cell corresponding to a pixel of the image is a self-luminescence type and coated with phosphors which emit visible lights of red, green and blue under ultraviolet rays emitted by the discharge. 
     A three-electrode structure PDP displays an image by generating sustain discharge between an X-electrode and Y-electrode. A cell to generate the sustain discharge (cell to be lighted) is selected by selectively generating address discharge, for example, between the Y-electrode and an address electrode. 
     In a typical PDP, the X-electrode and the Y-electrode are disposed on a front glass plate and the address electrode is disposed on a back glass plate. In addition, there has been recently proposed a PDP in which the three electrodes of the X-electrode, the Y-electrode, and the address electrode are disposed on the front glass plate (refer to Patent document 1, for example). 
     Patent document 1: Japanese Unexamined Patent Application Publication No. 2003-257321 
     DISCLOSURE 
     Problem to be Solved 
     In the PDP of Patent document 1, the Y-electrodes of the adjacent cells (one row electrode of row electrode pair) are disposed on both sides of the address electrode (column electrode). Accordingly, when the address discharge is generated between one side of the Y-electrodes adjacent to the address electrode and the address electrode, there is a probability that erroneous discharge is generated between the other side of the Y-electrodes adjacent to the address electrode and the address electrode. That is, when the cell to be lighted and the cell not to be lighted neighbor each other, there is a probability that the erroneous discharge is generated in the cell not to be lighted. In particular, in the case that the position of the address electrode is misaligned from the center of a barrier rib provided on the back glass plate to the opposite side of the corresponding Y-electrode because of an assembly error when adhering the glass plates, the generation probability of the erroneous discharge becomes higher between the address electrode and the Y-electrode in the adjacent cell. 
     A proposition of the present invention is to prevent the erroneous discharge in the adjacent cell when the address discharge is carried out in the PDP having the three electrodes on the front glass plate. 
     Means for Solving the Problems 
     A plasma display panel includes a first plate and a second plate facing each other via a discharge space. On the first plate, a first bus electrode and a second bus electrode are provided which extend in a first direction and are disposed at intervals. On the second plate, a plurality of two of the first barrier ribs adjacent to each other are provided which extend in a second direction perpendicular to the first direction and are disposed at intervals. Further, a cell is formed in a region surrounded by the first bus electrode, the second bus electrode and the first barrier ribs. 
     In the cell, a first display electrode is provided which is coupled to the first bus electrode and extends from the first bus electrode toward the second bus electrode. Further, in the cell, a second display electrode is provided which is coupled to the second bus electrode, extends from the second bus electrode toward the first bus electrode, and includes an opposed part of the first display electrode along a second direction. In addition, on the first plate, a dielectric layer is provided which covers the first bus electrode, the second bus electrode, the first display electrode and the second display electrode, and on the dielectric layer, a plurality of address electrodes are provided which are disposed at respective positions facing the first barrier ribs. The first display electrode and the second display electrode are disposed on both sides of one of the address electrodes adjacently, respectively, along the first direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view showing a first embodiment of the present invention. 
         FIG. 2  is an explanatory diagram of a main part in the PDP shown in  FIG. 1 . 
         FIG. 3  is a cross-sectional view of a main part in the PDP shown in  FIG. 1 . 
         FIG. 4  is an explanatory diagram showing an outline of the back plate part shown in  FIG. 1 . 
         FIG. 5  is an exploded perspective view showing an example of a plasma display device configured by using the PDP shown in  FIG. 1 . 
         FIG. 6  is a block diagram showing an outline of the circuit unit shown in  FIG. 5 . 
         FIG. 7  is a waveform chart showing an example of subfield discharge operation for displaying an image on the PDP shown in  FIG. 1 . 
         FIG. 8  is an explanatory diagram for a main part of a PDP in a second embodiment of the present invention. 
         FIG. 9  is a cross-sectional view for a main part of a PDP in the second embodiment of the present invention. 
         FIG. 10  is an explanatory diagram for a main part of a PDP in a third embodiment of the present invention. 
         FIG. 11  is an explanatory diagram for a main part of a PDP in a fourth embodiment of the present invention. 
         FIG. 12  is a cross-sectional view for a main part of a PDP in the fourth embodiment of the present invention. 
         FIG. 13  is an explanatory diagram for a main part of a PDP in a fifth embodiment of the present invention. 
         FIG. 14  is an exploded perspective view showing a sixth embodiment of the present invention. 
         FIG. 15  is an explanatory diagram for a main part of the PDP shown in  FIG. 14 . 
         FIG. 16  is a cross-sectional view for a main part of the PDP shown in  FIG. 14 . 
         FIG. 17  is an explanatory diagram showing an outline of the back plate part shown in  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be explained with reference to the drawings. 
       FIG. 1  shows a first embodiment of the present invention. The arrow D 1  in the drawing shows a first direction D 1  and the arrow D 2  shows a second direction D 2  which crosses the first direction D 1  perpendicularly in the plane parallel to an image display surface. A plasma display panel  10  (hereinafter, also called PDP) is configured with a front plate part  12  forming the image display surface and a back plate part  14  facing the front plate part  12 . The front plate part  12  and the back plate part  14  form a discharge space DS therebetween (in more detail, in a concave part of the back plate part  14 ). 
     The front panel part  12  has an X-bus electrode Xb (first bus electrode) and a Y-bus electrode Yb (second bus electrode) which are formed on a glass base FS (first plate) (lower side in the drawing) in parallel to the first direction D 1  and disposed alternately along the second direction D 2 , for generating the discharge repeatedly. The X-bus electrode Xb is coupled with an X-transparent-electrode Xt (first display electrode) which extends from the X-bus electrode Xb toward the Y-bus electrode Yb in the second direction D 2 . Further, the Y-bus electrode Yb is coupled with a Y-transparent-electrode Yt (second display electrode) which extends from the Y-bus electrode Yb toward the X-bus electrode Xb in the second direction D 2 . 
     Here, the X-bus electrode Xb and the Y-bus electrode Yb are opaque electrodes made of a metal material or the like, and the X-transparent-electrode Xt and the Y-transparent-electrode Yt are transparent electrodes which are made of ITO films or the like and transmit light. The transparent electrodes Xt and Yt are sometimes disposed over the whole areas between the respectively adhering bus electrodes Xb and Yb and the glass base FS. Further, the transparent electrodes Xt and Yt may be formed integrally with the bus electrodes Xb and Yb using the same material (metal material or the like) as that of the bus electrodes Xb and Yb. Then, an X electrode XE (sustain electrode) is configured with the X-bus electrode Xb and the X-transparent-electrode Xt, and a Y electrode YE (scan electrode) is configured with the Y-bus electrode Yb and the Y-transparent-electrode Yt. 
     The electrodes Xb, Xt, Yb and Yt are covered by a dielectric layer DL 1 . For example, the dielectric layer DL 1  is a silicon dioxide film (film of SiO 2 , film of silicon dioxide) formed by a CVD method. Then, on the dielectric layer DL 1  (lower side in the drawing) is provided a plurality of address electrodes AE which extend in the direction perpendicular to the bus electrodes Xb and Yb (second direction D 2 ). The address electrodes AE are covered by a dielectric layer DL 2  and the surface of the dielectric layer DL 2  is covered by a protective layer PL such as an MgO film or the like. 
     The back plate part  14 , which faces the front plate part  12  via the discharge space DS, includes first barrier ribs BR 1  formed on a glass base RS (second plate) in parallel to each other. The barrier rib BR 1  extends in the direction perpendicular to the bus electrodes Xb and Yb (second direction D 2 ) and faces the address electrode AE. In other words, the address electrode AE is disposed at a position facing the barrier rib BR 1 . The barrier rib BR 1  forms a side wall of a cell. Further, on the side of the barrier rib BR 1 , and on the glass base RS between the barrier ribs adjacent to each other, phosphors PHr, PHg, and PHb are coated which emit visible lights of red (R), green (G), and blue (B) respectively, by the excitation of the ultraviolet ray. 
     One pixel of the PDP  10  is configured with three cells which emit the red, green, and blue light, respectively. Here, one cell (pixel of one color) is formed in the discharge space DS defined by the bus electrodes Xb and Yb and the barrier ribs BR 1 . In this manner, the PDP  10  has the cells disposed in a matrix for displaying an image and also configured with alternately disposed plural kinds of cells which emit light with colors different from each other. While not illustrated particularly in the drawing, a display line is configured with the cells formed along the bus electrodes Xb and Yb. 
     The PDP  10  is made up by adhering the front plate part  12  and the back plate part  14  together so that the protective layer PL and the barrier rib BR 1  contact each other, and encapsulating discharge gas such as Ne, Xe, etc. into the discharge space DS. 
       FIG. 2  and  FIG. 3  show a main part of the PDP  10  shown in  FIG. 1 .  FIG. 2  shows a state of the electrodes Xb, Yb, Yt, and AE and the barrier rib BR 1  viewed from the image display surface side (upper side in  FIG. 3 ).  FIG. 3  shows a cross-section taken along the A-A′ line in  FIG. 2 . 
     When viewed from the image display surface side, the address electrode AE is provided at a position overlapping the barrier rib BR 1 . As described above, the cell C 1  is formed in the region surrounded by the bus electrodes Xb and Yb and the barrier ribs BR 1  (region surrounded by the bold broken line in  FIG. 2 ). 
     The X-transparent-electrode Xt and the Y-transparent-electrode Yt are provided for each cell C 1  and face each other along the second direction D 2 . Further, the transparent electrode Yt faces the corresponding address electrode AE (positioned in the left thereof in the drawing) via the dielectric layer DL 1 . Accordingly, by applying a voltage between the address electrode AE and the transparent electrode Yt, it is possible to generate address discharge in the discharge space DS of the focused cell C 1 . At this time, the barrier rib BR 1  works as a part of the dielectric layer and an electric field is generated in the discharge space DS between the address electrode AE and the transparent electrode Yt. 
     Further, the transparent electrodes Xt and Yt disposed along the display line DSL are disposed alternately along the first direction D 1 . Accordingly, in a pair of the cells C 1  adjacent to each other in the first direction D 1  sandwiching the address electrode AE, the transparent electrode Yt (scan electrode) in one of the cells C 1  neighbors the address electrodes AE on one side in the first direction D 1  (right side in the drawing), and the transparent electrode Xt (sustain electrode) of the other cell C 1  neighbors the address electrode AE on the other side in the first direction D 1  (left side in the drawing). In other words, in the pair of cells C 1  adjacent to each other in the first direction D 1  sandwiching the address electrode AE, the address electrode AE faces only the transparent electrode Yt on one side. 
     Accordingly, when generating the address discharge between the address electrode AE and the transparent electrode Yt of the focused cell C 1  (address period), it is possible to prevent the erroneous discharge from occurring in the adjacent cell C 1 . Thereby, even in the case that the position of the address electrode AE is shifted from the center of the barrier rib BR 1  to the opposite direction of the corresponding transparent electrode Yt (to the side of the transparent electrode Xt) when the front plate part  12  and the back plate part  14  are put together, the erroneous discharge is not generated in the adjacent cell C 1 . Accordingly, a higher assembly accuracy is not necessary for making the front plate part  12  and the back plate part  14  to adhere to each other in the PDP having three electrodes on the glass base FS (front glass plate), and it is possible to simplify the assembly process. 
       FIG. 4  shows an outline of the back plate part  14  shown in  FIG. 1 . In the periphery of the glass base RS, there is provided an exhaust hole EH passing through the glass base RS from the exhaust space ES to the outside surface. Thereby, the discharge space DS of the assembled PDP can be set to a vacuum state and the discharge gas can be encapsulated into the discharge space DS. Further, the discharge space DS and the exhaust space ES are formed by direct engraving of the glass base RS using a sandblast method or the like. That is, the barrier rib BR 1  is formed by the direct engraving of the glass base RS. Thereby, the production cost of the PDP can be reduced because a baking process is not necessary for forming the barrier rib BR 1 , for example. In many cases, a baking furnace for this baking process uses electricity as energy and omitting of this baking process also reduces the electric energy. The discharge space DS may be formed through the processes of coating of paste-state barrier rib material, drying, sandblasting, and baking. Further, the barrier rib BR 1  may be formed by the accumulation of printed layers. 
       FIG. 5  shows an example of a plasma display device configured by using the PDP  10  shown in  FIG. 1 . The plasma display device (hereinafter, also called PDP device) includes the PDP  10 , an optical filter  20  provided on the image display surface  16  side (light output side) of the PDP  10 , a front case  30  disposed on the image display surface  16  side of the PDP  10 , a rear case  40  and a base chassis  50  disposed on a rear plane  18  side of the PDP  10 , a circuit unit  60  attached on the rear case  40  side of the base chassis  50  for driving the PDP  10 , and a double-faced adhesive sheet  70  for adhering the PDP  10  to the base chassis  50 . The circuit unit  60  is configured with a plurality of components and thereby shown by a broken-line box in the drawing. The optical filter  20  is adhered on a protection glass (not shown in the drawing) which is attached to an opening part  32  of the front case  30 . The optical filter  20  is sometimes provided with an electromagnetic wave shielding function. Further, the optical filter  20  is sometimes adhered directly on the image display surface  16  side of the PDP  10  instead of the protection glass. 
       FIG. 6  shows an outline of the circuit unit  60  for driving the PDP  10  shown in  FIG. 1 . The circuit unit  60  includes an X-driver XDRV applying a common pulse to the bus electrodes Xb, a Y-driver YDRV selectively applying a pulse to the bus electrode Yb, an address driver ADRV selectively applying a pulse to the address electrode AE, a control unit CNT controlling the operation of the drivers XDRV, YDRV, and ADRV, and a power supply unit PWR. The drivers XDRV, YDRV, and ADRV operate as a driver unit driving the PDP  10 . The power supply unit PWR generates power supply voltages Vsc, Vs/2, −Vs/2, Vsa, etc. to be supplied to the drivers YDRV, XDRV, and ADRV. 
     The control unit CNT selects a subfield to be used according to image data R 0 - 7 , G 0 - 7 , and B 0 - 7 , and outputs control signals YCNT, XCNT, and ACNT to the drivers YDRV, XDRV, and ADRV, respectively. Here, the subfield is a field divided from one filed for displaying one screen of the PDP  10 , and the number of times of sustain discharge is determined for each subfield. Then, a multiple gradation image is displayed by selection of the subfield to be used for each cell C 1  composing the pixel. 
       FIG. 7  shows an example of the discharge operation in the subfield for displaying an image on the PDP  10  shown in  FIG. 1 . The star sign in the drawing shows generation of the discharge. Each of the subfields SF is configured with a reset period RST, an address period ADR, a sustain period SUS, and an erase period ERS. The erase period ERS is a period for generating discharge for reducing wall charge only in the lighted cell and thereby sometimes defined as one included in the sustain period SUS. 
     First, in the reset period RST, a gradually decreasing negative voltage (slope pulse) is applied to the sustain electrode XE (bus electrode Xb and transparent electrode Xt), and a positive voltage is applied to the scan electrode YE (bus electrode Yb and transparent electrode Yt) ( FIG. 7(   a )). Then, the sustain electrode XE is maintained to have a negative write voltage and a gradually increasing positive write voltage (write slope pulse) is applied to the scan electrode YE ( FIG. 7(   b )). Thereby, positive and negative wall charges are stored in the sustain electrode XE and the scan electrode YE, respectively, while cell luminescence is being suppressed. Next, a positive adjusting voltage is applied to the sustain electrode XE and a negative adjusting voltage (adjusting slope pulse) is applied to the scan electrode YE ( FIG. 7(   c )). Thereby, the amounts of the positive and negative wall charges which have been stored in the sustain electrode XE and the scan electrode YE, respectively, are reduced and also the wall charge amounts of all the cells become equal. The positive adjusting voltage is a voltage smaller than the voltage Vs/2 and the minimum value of the negative adjusting voltage is a voltage larger than the voltage −Vs/2, for example. 
     In the address period ADR, a scan voltage which becomes anode in the address discharge is applied to the sustain electrode XE, a scan pulse which becomes cathode in the address discharge is applied to the scan electrode YE, and an address pulse (voltage Vsa) which becomes anode in the address discharge is applied to the address electrode AE which corresponds to the cell to be lighted ( FIG. 7(   d )). The cell selected by the scan pulse and the address pulse has discharge temporarily. That is, a voltage larger than a minimum voltage for generating the discharge (firing voltage) is applied between the scan electrode YE and the address electrode AE, and a voltage smaller than the firing voltage is applied between the sustain electrode XE and the address electrode AE. Thereby, as described in above  FIG. 2 , the erroneous discharge is prevented from occurring between the sustain electrode XE of the adjacent cell and the address electrode AE when the address discharge is generated between the address electrode AE and the scan electrode YE of the focused cell. 
     The second address pulse shown in the waveform at the address electrode AE is applied for selecting a discharge cell in another display line ( FIG. 7(   e )). 
     In the sustain period SUS, negative and positive sustain pulses are applied to the sustain electrode XE and the scan electrode YE, respectively ( FIG. 7(   f ) and  FIG. 7(   g )). Thereby, the discharge state of the lighted cell is maintained. The sustain pulses having polarities different from each other are repeatedly applied to the sustain electrode XE and the scan electrode YE, respectively, and thereby the discharge of the cell lighted is repeatedly generated in the sustain period SUS. 
     In the erase period ERS, a negative pre-erase pulse and a positive high voltage pre-erase pulse are applied to the sustain electrode XE and the scan electrode YE, respectively, to generate discharge ( FIG. 7(   h )). Thereby, the wall charge is stored in the sustain electrode XE and the scan electrode YE. At this time, a voltage larger than the voltage V S/2  is applied to the scan electrode YE and thereby a relatively large amount of wall charge is stored in the scan electrode YE. Next, a positive erase pulse and a negative erase pulse are applied to the sustain electrode XE and the scan electrode YE, respectively ( FIG. 7(   i )). While discharge is generated thereby, the wall charge amount is reduced compared to that in the sustain period SUS because a voltage value difference applied between the two electrodes is smaller than the voltage value difference in the sustain period SUS. 
     As described above, in the first embodiment, the transparent electrodes Xt and Yt are disposed alternately along the first direction D 1  (direction perpendicular to the address electrode AE). That is, in the cells adjacent to each other in the first direction D 1  via the address electrode AE, the transparent electrodes Yt of both cells C 1  do not neighbor on the both sides of one address electrode AE. As a result, it is possible to prevent the erroneous discharge in the cell C 1  adjacent via the address electrode AE. 
     Further, even in the case that the position of the address electrode AE is shifted from the center of the barrier rib BR 1  to the opposite side of corresponding transparent electrode Yt (transparent electrode Xt side), the erroneous discharge is not generated between the address electrode AE and the transparent electrode Xt, and thereby a higher assembly accuracy is not necessary for making the front plate part  12  and the back plate part  14  to adhere to each other, resulting in simplifying the assembly process. 
     Further, since the back plate part  14  is not provided with the address electrode AE, the barrier rib BR 1  can be formed by the direct engraving of the glass base RS. Thereby, it is possible to reduce the production cost of the PDP  10  because the baking process is not necessary for forming the barrier rib BR 1 . 
       FIG. 8  and  FIG. 9  show a main part of a PDP  10  in a second embodiment of the present invention. This embodiment is different from the first embodiment in that a projection part Ap is provided to the address electrode AE. The configuration except the shape of the address electrode AE is the same as that of the first embodiment ( FIG. 1  to  FIG. 4 ). The same element described in the first embodiment is denoted by the same symbol and detailed description thereof will be omitted. Further, the discharge operation for displaying an image on the PDP  10  of this embodiment and a PDP device using the PDP  10 , is the same as that of the first embodiment ( FIG. 5  to  FIG. 7 ) except the voltage values (e.g. voltages Vsc and Vsa shown in  FIG. 7 ). 
       FIG. 8  shows a state of the electrodes Xb, Xt, Yb, Yt, and AE and the barrier rib BR 1  viewed from the image display surface side (upper side in  FIG. 9 ), and  FIG. 9  shows a cross-section taken along the A-A′ line in  FIG. 8 . 
     The projection part Ap is formed integrally with the address electrode AE, projecting from the address electrode AE between an end of the transparent electrode Yt and the bus electrode Xb. That is, the projection part Ap is disposed on the discharge space DS of the cell C 1  corresponding to the address electrode AE via the dielectric layer DL 2  and the protective layer PL. Since the projection part Ap is formed on the discharge space DS, the firing voltage can be reduced in generating the discharge between the projection part Ap and the transparent electrode Yt. That is, the voltage applied between the address electrode AE and the transparent electrode Yt, for example, the voltage Vsa shown in  FIG. 7 , can be reduced. The projection part AP, while disposed close to the bus electrode Xb (sustain electrode), does not generate the erroneous discharge in the address discharge as same as the above described transparent electrode Xt (sustain electrode) of the adjacent cell. 
     As described above, also in the second embodiment, it is possible to obtain the same effect as that of the first embodiment. Further, in this embodiment, since the discharge is generated between the projection part Ap formed on the discharge space DS and the transparent electrode Yt, it is possible to reduce the voltage to be applied during the address period, for example, the voltage Vsa shown in  FIG. 7 . As a result, power consumption in the driver circuit of the address electrode AE (e.g. address driver ARDV shown in  FIG. 6 ) can be reduced. In addition, the reduction of the voltage Vsa further suppresses generation of the erroneous discharge in the adjacent cell C 1 . In the case that the same voltage as that in the first embodiment (e.g. difference between the voltage Vsa and the voltage −Vs/2 shown in  FIG. 7 ) is applied between the address electrode AE and the electrode YE, it is possible to generate the address discharge without fail because the firing voltage is lower than that in the first embodiment. 
       FIG. 10  shows a main part of a PDP  10  in a third embodiment of the present invention. This embodiment is different from the second embodiment in the projection part Ap 2  provided to the address electrode AE. The other configuration except the projection part Ap 2  of the address electrode AE is the same as that of the second embodiment. The same element as that described in the first and second embodiments ( FIG. 1  to  FIG. 4 ,  FIG. 8 , and  FIG. 9 ) is denoted by the same symbol, and detailed description thereof will be omitted. Further, the discharge operation for displaying an image on the PDP  10  of this embodiment and a PDP device using the PDP  10  is the same as that in the first embodiment ( FIG. 5  to  FIG. 7 ) except the voltage values (e.g. voltages Vsc and Vsa shown in  FIG. 7 ). 
       FIG. 10  shows a state of the electrodes Xb, Xt, Yb, Yt, and AE and the barrier rib BR 1  viewed from the image display surface side (upper side in  FIG. 9 ). Further, the cross-section taken along the A-A′ line in  FIG. 10  is the same as that in above  FIG. 9 . 
     The projection part Ap 2  is formed integrally with the address electrode AE projecting from the address electrode AE between the end of the transparent electrode Yt and the bus electrode Xb. Further, a part of the projection part Ap 2  is disposed at a position which overlaps the end of the transparent electrode Yt with the dielectric layer DL 1  (broken line part in  FIG. 10 ) therebetween. Thereby, the distance between the projection part Ap 2  of the address electrode AE and the transparent electrode Yt can be reduced and the firing voltage can be further reduced when the discharge is generated between the projection part Ap 2  and the transparent electrode Yt. As a result, it is possible to further reduce the voltage to be applied between the address electrode AE and the transparent electrode Yt, for example, the above voltage Vsa shown in  FIG. 7 , in the generation of the address discharge. 
     As described above, also in the third embodiment, it is possible to obtain the same effect as that of the above first and second embodiments. Further, it is possible to further reduce the voltage to be applied between the address electrode AE and the transparent electrode Yt, for example, the above voltage Vsa shown in  FIG. 7  in the generation of the address discharge. 
       FIG. 11  and  FIG. 12  show a main part of a PDP in a fourth embodiment of the present invention. This embodiment is different from the first embodiment in the position where the address electrode AE is disposed. The other configuration is the same as that of the first embodiment ( FIG. 1  to  FIG. 4 ). The same element as that described in the first embodiment is denoted by the same symbol and detailed description thereof will be omitted. Further, the discharge operation for displaying an image on the PDP  10  of this embodiment and a PDP device using the PDP  10  is the same as that in the first embodiment ( FIG. 5  to  FIG. 7 ) except the voltage values (e.g. voltage Vsc and Vsa shown in  FIG. 7 ). 
       FIG. 11  shows a state of the electrodes Xb, Xt, Yb, Yt, and AE and the barrier rib BR 1  viewed from the image display surface side (upper side in  FIG. 12 ), and  FIG. 12  shows a cross-section taken along the A-A′ line in  FIG. 11 . 
     The address electrode AE is disposed nearer to the transparent electrode Yt side in relation to the center of the barrier rib BR 1 . For example, a part of the address electrode AE is disposed so as to protrude from the barrier rib BR 1  to the transparent electrode Yt side. The address electrode AE may be disposed nearer to the transparent electrode Yt side without protruding from the barrier rib BR 1  to the transparent electrode Yt side. Thereby, the distance between the address electrode AE and the transparent electrode Yt can be reduced and the firing voltage can be reduced when the discharge is generated between the address electrode AE and the transparent electrode Yt. 
     As described above, also in the fourth embodiment, it is possible to obtain the same effect as that of the above first embodiment. Further, in this embodiment, the firing voltage can be reduced and thereby it is possible to obtain the same effect as that of the above second embodiment. 
       FIG. 13  shows a main part of a PDP in a fifth embodiment of the present invention. This embodiment is different from the first embodiment in the line width of a part of the electrodes Xb, Yb, or AE. The other configuration is the same as that of the first embodiment ( FIG. 1  to  FIG. 4 ). The same element as that described in the first embodiment is denoted by the same symbol and detailed description thereof will be omitted. Further, the discharge operation for displaying an image on the PDP  10  of this embodiment and a PDP device using the PDP  10  is the same as that in the first embodiment ( FIG. 5  to  FIG. 7 ) except the voltage values (e.g. voltage Vsc and Vsa shown in  FIG. 7 ). 
       FIG. 13  shows a state of the electrodes Xb, Xt, Yb, Yt, and AE and the barrier rib BR 1  viewed from the image display surface side (upper side in  FIG. 3 ). Further, the cross-section taken along the A-A′ line in  FIG. 13  is the same as that in above  FIG. 3 . 
     In an intersection area CA where the electrode Xb or Yb and the electrode AE intersect with each other, the address electrode AE is formed with a narrower line width than that of the part excluding the intersection area CA. That is, the bus electrodes Xb and Yb are formed with the same line widths as those in the first embodiment, and only the address electrode AE is formed with a narrower line width in the intersection area CA than that of the part excluding the intersection area CA of the address electrode AE. The bus electrode Xb or Yb may be formed with a narrower line width in the intersection area CA than the line width of the part excluding the intersection area CA. Since the intersection area CA is formed with the narrower line width, it is possible to reduce a wiring capacitance formed between the electrode Xb or Yb and the electrode AE. 
     As described above, also in the fifth embodiment, it is possible to obtain the same effect as that of the above first embodiment. Further, since the wiring capacitance formed between the electrode Xb or Yb and the electrode AE is smaller in this embodiment, it is possible to save the driving force of the driver circuits for the electrodes Xb and Yb and the electrode AE (e.g. drivers XDRV, YDRV, and ADRV shown in  FIG. 5 ) and to reduce the power consumption. 
       FIG. 14  shows a sixth embodiment of the present invention. This embodiment is different from the first embodiment in that a second barrier rib BR 2  is provided on the glass base RS. The other configuration is the same as that of the first embodiment ( FIG. 1  to  FIG. 4 ). The same element as that described in the first embodiment is denoted by the same symbol and detailed description thereof will be omitted. Further, the discharge operation for displaying an image on the PDP  10  of this embodiment and a PDP device using the PDP  10  is the same as that in the first embodiment ( FIG. 5  to  FIG. 7 ) except the voltage values (e.g. voltages Vsc and Vsa shown in  FIG. 7 ). 
     The second barrier ribs BR 2  are formed on the glass base RS in the first direction D 1  and face the bus electrodes Xb and Yb. The side walls of the cell are formed by the barrier ribs BR 1  and BR 2 . That is, the discharge spaces DS of the cells are separated from each other by the barrier ribs BR 1  and BR 2 . Thereby, it is possible to prevent the erroneous discharge in the cell adjacent in the second direction D 2 . 
       FIG. 15  and  FIG. 16  show a main part of the PDP shown in  FIG. 14 .  FIG. 15  shows a state of the electrodes Xb, Xt, Yb, Yt, and AE and the barrier ribs BR 1  and BR 2  viewed from the image display surface side (upper side in  FIG. 16 ).  FIG. 16  show a cross-section taken along the A-A′ line in  FIG. 15 . 
     When viewed from the image display surface side, the bus electrodes Xb and Yb are provided at positions overlapping the barriers BR 2 . The cell C 1  is formed in a region surrounded by the barrier ribs BR 1  and BR 2  (region surrounded by the bold broken line in  FIG. 15 ). Since the bus electrodes Xb and Yb are disposed on the barrier ribs BR 2 , the erroneous discharge between the bus electrodes Xb and Yb adjacent in the second direction D 2  can be prevented. That is, it is possible to prevent the erroneous discharge in the cell adjacent in the second direction D 2 . Thereby, it is possible to reduce the distance between the bus electrodes Xb and Yb and to increase the area of each cell C 1 . 
       FIG. 17  shows an outline of the back plate part  14  shown in  FIG. 14 . The same element as that described in above  FIG. 4  is denoted by the same symbol and detailed description thereof will be omitted. 
     The barrier ribs BR 1  and BR 2  are formed by the direct engraving of the glass base RS by the sandblast method or the like. That is, the barrier rib BR 2  is formed integrally with the barrier rib BR 1 . 
     As described above, also in the sixth embodiment, it is possible to obtain the same effect as that of the above first embodiment. Further, since the cells C 1  are separated from each other by the barrier ribs BR 1  and BR 2  in this embodiment, it is possible to prevent the erroneous discharge in each of the cells adjacent in the four directions. 
     Note that the above embodiments describe the examples in which one pixel is configured with three cells (red (R), green (G), and blue (B)). The present invention is not limited to such embodiments. For example, one pixel may be configured with four or more cells. Alternatively, one pixel may be configured with cells which emit colors except red (R), green (G) and blue (B), and also may include a cell which emits a color except red (R), green (G), and blue (B). 
     The above second and third embodiments describe the examples in which the projection parts Ap and Ap 2  are formed integrally with the address electrode AE, respectively. The present invention is not limited to such embodiments. For example, the projection parts Ap and Ap 2  may be formed by transparent electrodes coupled to the address electrode AE. Also in this case, it is possible to obtain the same effect as that of the above second or third embodiment. Further, since the projection parts Ap and Ap 2  are formed by the transparent electrodes, it is possible to widen the light transmission region in each cell. 
     As described above, the present invention has been described in detail, but the above embodiments and modification examples thereof are only examples of the invention and the present invention is not limited thereto. It is obvious that modification is possible in the range without departing from the present invention. 
     The many features and advantages of the embodiments are apparent from the detailed specification and, thus it is intended by the appended claims to cover all such features and advantages of the embodiments that fall within the true spirit and scope thereof. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the inventive embodiments to exact construction and operation illustrated and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope thereof.