Abstract:
A plasma display panel is provided. The plasma display panel comprises a plurality of first electrodes and a plurality of second electrodes; wherein the first electrodes and the second electrodes cross at a discharge space; wherein prominent electrodes and formed at a portion o the first electrodes where the first electrodes cross with the second electrodes to extend the area of the address electrodes so that a stable address discharge may occur, and vertical centers of the prominent electrodes are asymmetrical with respect to vertical centers of the discharge spaces, which may be coated with red, green and blue fluorescent layers.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of prior application Ser. No. 10/942,049, filed on Sep. 16, 2004, and claims priority to and the benefit of Korean Patent Application No. 2003-66507, filed on Sep. 25, 2003, which are both hereby incorporated by reference for all purposes as if fully set forth herein. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a display panel, and more particularly, to a display panel in which shapes of address electrodes may be improved to prevent cross-talk. 
   2. Discussion of the Related Art 
   Plasma display panels (PDP) are generally referred to as flat display devices. In a typical PDP, a discharge gas is injected between two substrates on which a plurality of electrodes are formed, the two substrates are sealed, and a discharge voltage is applied to the substrates. When the discharge gas radiates between two electrodes, a proper pulse voltage is applied to the two electrodes to perform addressing in a place where the two electrodes cross. The discharge gas is excited to produce ultraviolet light, which in turn excites a fluorescent layer thereby producing visible images. 
   Such a PDP may be a direct current (DC) PDP or an alternating current (AC) PDP, depending upon the drive voltage that is applied to a discharge cell. Depending upon discharge cell electrode structure, PDPs may also be classified as a face discharge type and a surface discharge type. 
   With a DC PDP, all electrodes are exposed to a discharge space and electric charges directly move between facing electrodes. With an AC PDP, at least one electrode is covered with a dielectric layer so that instead of directly moving electric charges between facing electrodes, ions and electrons generated due to a discharge produce a wall voltage by sticking to the dielectric layer&#39;s surface, and the discharge is sustained by a sustaining voltage. 
   In a face discharge type PDP, an address electrode faces a scan electrode in each unit pixel, and addressing and sustaining discharges occur between them. In a surface discharge type PDP, an address electrode and a sustaining electrode are prepared in each unit pixel to cause addressing and sustaining discharges. 
     FIG. 1  shows a unit cell of a conventional PDP  10 . Referring to  FIG. 1 , the conventional PDP  10  includes a front substrate  11  and a rear substrate  15  facing the front substrate  11 . A pair of sustaining electrodes  12  are formed on the front substrate  11  to predetermined width and height, a front dielectric layer  13  is formed on the sustaining electrodes  12  using a printing method, and a protection layer  14  is formed on the front dielectric layer  13 . 
   An address electrode  16  is formed on the rear substrate  15  to predetermined width and height, and a rear dielectric layer  27  is formed on the address electrode  16 . Barrier ribs  18  are disposed on the rear dielectric layer  17  to prevent cross-talk from occurring between adjacent discharge cells. Red, green, and blue fluorescent layers  19  are formed on an upper surface of the rear dielectric layer  17  and on inner walls of the barrier ribs  18 . 
   An inert gas is injected into a space between the front and rear substrates  11  and  15  to form a discharge area  100 . 
   The operation of the conventional PDP  10  having the above-described structure will now be described in brief. 
   When a drive voltage is applied to the sustaining electrodes  12 , a surface discharge occurs from the front dielectric layer  13  and the discharge area  100  on the protection layer  14 . The discharge produces ultraviolet rays that excite the red, green, and blue fluorescent layers  19  to achieve a color display. 
   In other words, the drive voltage accelerates the discharge cell space charges, which collide with a pressurized penning gas comprised of an inert gas such as neon (Ne) mixed with helium (He), xenon (Xe), or other like gases. 
   As a result, the inert gas produces ultraviolet rays of 147 nanometers, which then collide with the red, green, and blue fluorescent layers  19  to produce visible rays. 
     FIG. 2  shows an electrode structure according to the prior art. Referring to  FIG. 2 , X and Y electrodes  21  and  22  are alternately arranged in a stripe shape on the front substrate  11  of  FIG. 1 . Address electrodes  23  are arranged in a stripe shape, on the rear substrate  15  of  FIG. 1 , orthogonally to the X and Y electrodes  21  and  22 . Barrier ribs  24  disposed between the address electrodes  23  define discharge spaces. 
   However, since these conventional electrodes have wide widths, they cause high power consumption when representing low gray scale or actual moving pictures. Thus, prominent electrodes have been suggested to solve these problems. 
     FIG. 3  shows a layout of prominent electrodes according to the prior art. Referring to  FIG. 3 , X and Y electrodes  31  and  32  are alternately arranged in a stripe shape on the front substrate  11 . Address electrodes  33  are arranged in a stripe shape, on the rear substrate  15  of  FIG. 3 , orthogonally to the X and Y electrodes  31  and  32 . Barrier ribs  34  are formed between the address electrodes  33 . Prominent electrodes  35  are formed at portions of the address electrodes  33  that cross with the Y electrodes  32  so as to provide a suitable electrode area for stable address discharging. The prominent electrodes  35  protrude from sidewalls of the address electrodes  33  to a predetermined width. 
   The electrode structure of  FIG. 3  is an asymmetric structure in which a width W 3  of an area B coated with a blue fluorescent layer is wider than widths W 1  and W 2  of areas R and G coated with red arid green fluorescent layers. Thus, a sufficient gap may exist between the address electrode  33 G and the address electrode  33 B. As a result, the address electrodes  33 G and  33 B may be prevented from interfering with electric charge characteristics of the green and blue fluorescent layers. 
   However, a sufficient gap may not exist between the address electrode  33 R and the address electrode  33 G, which may affect an electric field between them. In this case, external factors may easily affect the wall charges of the address electrodes  33 , which may result in undesired cross-talk. 
     FIG. 4  shows a second layout of prominent electrodes according to the prior art. Referring to  FIG. 4 , a width W 6  of an area B coated with a blue fluorescent layer has the same size as widths W 4  and W 5  of areas R and G coated with red and green fluorescent layers. Prominent electrodes  45  are formed at portions of address electrodes  43  that cross with Y electrodes  42 . Similar to  FIG. 2  and  FIG. 3 , the X and Y electrodes  41  and  42  are alternately arranged in a stripe shape. 
   In this case, a sufficient gap may not exist between an address electrode  43 G and an address electrode  43 B. Thus, although a bather rib  44  is disposed between the address electrodes  43 G and  43 B, they may affect an electric field distribution according to electric charge characteristics of the green and blue fluorescent layers. 
   SUMMARY OF THE INVENTION 
   Accordingly, the present invention is directed to a plasma display panel that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. 
   The present invention provides an improved PDP in which arrangement gaps of prominent electrodes may vary so as to reduce power consumption and achieve a suitable discharge. 
   Additional features of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. 
   The present invention discloses a display panel, comprising a plurality of first electrodes and a plurality of second electrodes; wherein the first electrodes and the second electrodes cross at a discharge space. Prominent electrodes are formed at a portion of the first electrodes where the first electrodes cross the second electrodes, and vertical centers of the prominent electrodes are asymmetrical with respect to vertical centers of the discharge spaces. 
   The present invention also discloses a display panel, comprising a plurality of first electrodes and a plurality of second electrodes; wherein the first electrodes and the second electrodes cross at a discharge space; wherein prominent electrodes are formed on sidewalls of portions of the first electrodes that cross with the second electrodes, and vertical centers of the prominent electrodes being arranged at different distances from vertical centers of the discharge spaces. 
   The present invention also discloses a display panel, comprising a plurality of first electrodes and a plurality of second electrodes; wherein the first electrodes and the second electrodes cross at a discharge space; and prominent electrodes which are formed on sidewalls of portions of the first electrodes that cross with the second electrodes, vertical centers of the prominent electrodes being arranged at different distances from vertical centers of the discharge spaces, the prominent electrodes protruding from opposite sidewalls of the first electrodes that are arranged in adjacent discharge spaces according to electric charge characteristics of adjacent fluorescent layers. 
   It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. 
       FIG. 1  shows a unit cell of a conventional PDP. 
       FIG. 2  shows a PDP electrode arrangement according to the prior art. 
       FIG. 3  shows a PDP electrode arrangement according to the prior art. 
       FIG. 4  shows a PDP electrode arrangement according to the prior art. 
       FIG. 5  shows a PDP according to an exemplary embodiment of the present invention. 
       FIG. 6  shows an electrode arrangement, according to an exemplary embodiment of the present invention, for the PDP of  FIG. 5 . 
       FIG. 7  shows an electrode arrangement according to a second exemplary embodiment of the present invention. 
       FIG. 8A  and  FIG. 8B  are cross-sectional views along line VIII-VIII′ of  FIG. 6 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the attached drawings. 
     FIG. 5  is an exploded perspective view of a portion of a PDP  50 . Referring to  FIG. 5 , the PDP  50  includes a front substrate  51  and a rear substrate  510  facing the front substrate  51 . 
   X and Y electrodes  52  and  53  are alternately arranged as sustaining electrodes  54  at predetermined distances on a lower surface of the front substrate  51 . Discharge spaces are formed between the X and Y electrodes  52  and  53 . The X and Y electrodes  52  and  53  have a stripe shape, and may be formed of transparent conductive layers. Bus electrodes  55  are formed on lower surfaces of the X and Y electrodes  52  and  53  to reduce a line resistance of the sustaining electrodes  54 . 
   An area between a pair of adjacent sustaining electrodes  54  corresponds to a non-discharge area, where a black matrix layer may be formed to improve the PDP&#39;s contrast. 
   A front dielectric layer  56  formed on the front substrate  51  covers the sustaining electrodes  54  and the bus electrodes  55 . A protection layer  57 , which may be made of magnesium oxide, covers the front dielectric layer  56 . 
   Address electrodes  520  are formed at predetermined distances on an upper surface of the rear substrate  510 , and they are arranged orthogonally to the X and Y electrodes  52  and  53 . A rear dielectric layer  530  covers the address electrodes  520 . Barrier ribs  540  formed on an upper surface of the rear dielectric layer  530  define discharge spaces and may prevent cross-talk. The bather ribs  540  are arranged parallel with the address electrodes  520 . Red, green, and blue fluorescent layers  550 R,  550 G, and  550 B are formed on inner walls of the barrier ribs  540  and the upper surface of the rear dielectric layer  530  to fill the discharge spaces. 
   Here, the red, green, and blue fluorescent layers  550 R,  550 G, and  550 B coat the discharge spaces, which may have different brightness and size. In other words, the discharge space that is coated with the blue fluorescent layer  550 B has a relatively lower brightness and is wider than the discharge spaces that are coated with the red and green fluorescent layers  550 R and  550 G. Thus, in this exemplary embodiment of the present invention, the discharge spaces are asymmetric. 
   An exemplary embodiment of the present invention has prominent electrodes  560  that protrude from the address electrodes  520  to different sizes and at different distances in the discharge spaces which are coated with the red, green, and blue fluorescent layers  550 R,  550 G, and  550 B, and vertical centers of the prominent electrodes  560  are not arranged at equal distances from vertical centers of the discharge spaces. 
     FIG. 6  is a schematic view of the arrangement of the address electrodes  520 , the barrier ribs  540 , the X and Y electrodes  52  and  53 , and red, green, and blue fluorescent layers  550 R,  550 G, and  550 B of  FIG. 5 , as discussed above. 
   Referring to  FIG. 6 , a width W 9  of an area which is coated with the blue fluorescent layer  550 B is wider than widths W 7  and W 8  of areas which are coated with the red and green fluorescent layers  550 R and  550 G. In other words, the discharge space which is coated with the blue fluorescent layer  550 B is wider than the discharge spaces which are coated with the red and green fluorescent layers  550 R and  550 G. 
   Here, an address discharge occurs between the address electrodes  520  and the Y electrodes  53 . Thus, the prominent electrodes  560  are formed at the address electrodes  520  to provide a suitable electrode area for stable address discharging. The prominent electrodes  560  may be formed as a separate layer on top of the address electrodes  520 , as shown in  FIG. 8A . Preferably, the prominent electrodes  560  are formed coplanar with the address electrodes  520 , as shown in  FIG. 8B . The prominent electrodes  560  are arranged differently in the areas coated with red, green, and blue fluorescent layers  550 R,  550 G, and  550 B. 
   Specifically, prominent electrodes  561  are symmetrically formed on both sidewalls of the address electrode  521 . In other words, the prominent electrodes  561  are formed by the left and right sidewalls of a vertical axis along which the address electrode  521  is arranged, so as to have the same area. 
   A prominent electrode  562  is asymmetrically formed in that it is only on one sidewall of an address electrode  522  in the area which is coated with the red fluorescent layer  550 R. A prominent electrode  563  is asymmetrically formed in that it is only on one sidewall of an address electrode  523  in the area which is coated with the green fluorescent layer  550 G. 
   The prominent electrode  562  protrudes from the left sidewall of the address electrode  522 , in an opposite direction to the address electrode  523 . The prominent electrode  562  does not protrude from the right sidewall of the address electrode  522  that faces the address electrode  523 . 
   The prominent electrode  563  protrudes from a sidewall of the address electrode  523 , in an opposite direction to the address electrode  522 . The prominent electrode  563  does not protrude from a sidewall of the address electrode  523  that faces the address electrode  522 . 
   To summarize, the prominent electrode  562  protrudes from the left sidewall of the address electrode  522 , and the prominent electrode  563  protrudes from the right sidewall of the address electrode  523 . In other words, the prominent electrodes  562  and  563  protrude from only one sidewall of the left and right sidewalls of vertical axes along which the address electrodes  522  and  523  are arranged. Thus, a sufficient gap may be maintained between the prominent electrodes  562  and  563 . 
   As a result, vertical centers of the prominent electrodes V p  are not arranged at equal distances from the vertical centers of the discharge spaces V d  which are coated with the red, green, and blue fluorescent layers  550 R,  550 G, and  550 B. 
   In the PDP  50  having the above-described structure, a voltage may be applied between the Y electrodes  53  and the address electrodes  520  to cause a preliminary discharge that charges wall charges. In this state, a voltage may be applied between the X and Y electrodes  52  and  53  to cause a sustaining discharge that produces plasma. 
   Ultraviolet rays radiate from the plasma to excite the red, green, and blue fluorescent layers  550 R,  550 G, and  550 B so as to realize an image. 
   Here, the prominent electrodes  562  and  563  are arranged on different sides of address electrodes  522  and  523 , respectively, which are arranged in relatively narrow discharge spaces. Thus, the prominent electrodes  562  and  563  contribute to securing the electrode area suitable for the stable address discharge and the sufficient gap therebetween. As a result, crosstalk may be prevented. 
     FIG. 7  is a schematic view for showing the arrangement of electrodes and barrier ribs according to a second exemplary embodiment of the present invention. Referring to  FIG. 7 , the X and Y electrodes  52  and  53  are alternately arranged at predetermined distances on the front substrate  51  of  FIG. 5 . Address electrodes  720  are arranged on the rear substrate  510  orthogonally to the X and Y electrodes  52  and  53 . Barrier ribs  740  are installed between adjacent address electrodes  720 . 
   The barrier ribs  740  define discharge spaces that are coated with red, green, and blue fluorescent layers  750 R,  750 G, and  750 B. Unlike the previous exemplary embodiment, widths W 10 , W 11 , and W 12  of areas which are coated with the red, green, and blue fluorescent layers  750 R,  750 G, and  750 B, are the same so that the discharge spaces are symmetrical. 
   Prominent electrodes  760  are formed at the address electrodes  720  to secure the electrode area suitable for a stable address discharge. The prominent electrodes  760  protrude from sidewalls of the address electrodes  720  where the address electrodes  720  cross with the Y electrodes  53 . 
   Although the barrier ribs  740  are positioned between the discharge spaces, the address electrodes  720  may affect a mutual electric field distribution due to the electric charge characteristics of the red, green, and blue fluorescent layers  750 R,  750 G, and  750 B, 
   In other words, wall charges of an address electrode  721  in the area that is coated with the blue fluorescent layer  750 B and an address electrode  723  in the area that is coated with the green fluorescent layer  750 G may be easily affected by external factors, which may cause cross-talk. 
   In order to prevent cross-talk, the prominent electrode  761  may be asymmetrically formed on a sidewall of the address electrode  721 , and the prominent electrode  763  may be asymmetrically formed on a sidewall of the address electrode  723 . 
   In other words, the prominent electrode  761  protrudes from the right sidewall only of the address electrode  721 , and the prominent electrode  763  protrudes from the left sidewall only of the address electrode  723 . 
   The prominent electrodes  761  and  763  are not formed on sidewalls of the address electrodes  721  and  723  that face each other. 
   The prominent electrodes  761  and  763  may contribute to securing an electrode area suitable for the address discharge and a sufficient gap between the address electrodes  721  and  723 . As a result, the address electrodes  721  and  723  may not affect a mutual electric field distribution, which would result in preventing cross-talk. 
   Comparing the address electrodes  721  and  723  in the areas which are coated with the green and blue fluorescent layers  750 G and  750 B with an address electrode  722  in the area which is coated with the red fluorescent layer  750 R, electric charges of the red, green, and blue fluorescent layers  750 R,  750 G, and  750 B are stable enough that they may not interfere with one another. As a result, the address electrodes  721 ,  722 , and  723  may not affect a mutual electric field distribution. 
   In this case, prominent electrodes  762  are symmetrically formed on both sidewalls of the address electrode  722 . The prominent electrodes  762  are formed by the left and right sidewalls of a vertical axis along which the address electrode  722  is arranged, so as to have the same area. 
   As described above, in a PDP according to exemplary embodiments of the present invention, prominent electrodes may be formed at portions of address electrodes that cross with Y electrodes, so that a stable address discharge may occur. The prominent electrodes may contribute to securing sufficient gaps among the address electrodes, which may be arranged under red, green, and blue fluorescent layers, so as to prevent cross-talk and improve a margin of a drive voltage. 
   Exemplary embodiments of the present invention discussed above refer to quadrangular shaped prominent electrodes. The present invention is not limited, however, to such shapes. For example, prominent electrodes may be shaped as half-circles, or the quadrangular shapes may have rounded corners. Consequently, prominent electrodes on adjacent address electrodes need not be the same shape. 
   While exemplary embodiments of the present invention have been described with reference to an AC PDP, the present invention is not limited to an AC PDP. It may be applicable to any display device that includes an electrode structure in which a panel displays images by the mutual drive of electrodes placed on facing substrates such as DC PDPs, electroluminescence displays (ELD), liquid crystal displays (LCD), and field emission displays (FED). 
   It will be apparent to those skilled in the art that various modifications and variation can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.