Patent Publication Number: US-7719190-B2

Title: Plasma display panel

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION 
     This application claims the benefit of Korean Patent Application No. 10-2006-0034174, filed on Apr. 14, 2006, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present embodiments relate to a plasma display panel (PDP), and more particularly, to a plasma display panel that can both improve contrast and prevent cross-talk between discharge cells. 
     2. Description of the Related Art 
     Plasma Display Panels (PDPs), which display images using a gas discharge, are known for their excellent display capabilities such as brightness, contrast, residual image, viewing angle, etc., and have drawn attention as display devices that can replace cathode ray tubes. PDPs emit light by exciting phosphor using an emission of ultraviolet rays occurring with a discharge between electrodes which is generated by a direct current voltage (DC voltage) or an alternating current voltage (AC Voltage) applied to the electrodes. 
     A PDP includes a first substrate and a second substrate which face each other to form a discharge space, a plurality of pairs of discharge sustain electrodes that are disposed on the first substrate, a plurality of address electrodes that are disposed on the second substrate, and barrier ribs that define the discharge space into a plurality of discharge cells. 
     The discharge sustain electrodes are disposed in pairs of an X electrode and a Y electrode, so that X electrodes and Y electrodes are disposed in an X-Y-X-Y . . . order. Therefore, an X electrode and a Y electrode are adjacent between adjacent discharge cells, thus generating cross-talk. 
     Referring to  FIG. 1  for a more detailed description, the X electrodes and the Y electrodes are sequentially disposed in a Y 1 , X 1 , Y 2 , X 2 . . . order in the vertical direction of the paper, each X and Y electrode extending in the horizontal direction of the paper, and the address electrodes are disposed to intersect the X and Y electrodes at right angles in an A 1 , A 2 , . . . order. A first discharge cell (C 1 ) is formed where A 1  crosses X 1  and Y 1 , and a second discharge cell (C 2 ) is formed where A 1  crosses X 2  and Y 2 . 
     Here, the X 1  electrode and the Y 2  electrode are adjacent, thereby allowing cross-talk. 
     In PDPs, black stripes are formed of a black insulator between each pair of discharge sustain electrodes, that is, between each pair of X and Y electrodes, to improve contrast. A typical example of the black stripes is disclosed in U.S. Pat. No. 5,661,500. 
     However, this remains problematic in that a separate space is needed for disposing black stripes to improve contrast, which diminishes the discharge cell area and increases the number of the manufacturing steps. 
     Thus, the present embodiments, contrived to solve problems including those mentioned above, are intended to provide a plasma display panel that can improve contrast and prevent cross-talk between discharge cells. 
     SUMMARY OF THE INVENTION 
     The present embodiments provide a plasma display panel (PDP) including a first substrate and a second substrate bonded to face each other; a plurality of discharge cells disposed between the first and second substrates; a plurality of X electrodes crossing the discharge cells and formed between the first and second substrates; and a plurality of Y electrodes crossing the discharge cells and formed between the first and second substrates, wherein the X electrodes are shared by the discharge cells in the direction perpendicular to the direction in which the X and Y electrodes extend. 
     The present embodiments also provide a PDP including a first substrate and a second substrate bonded to face each other; a plurality of X electrodes formed on the surface of the first substrate facing the second substrate, apart a predetermined distance from each other; and a plurality of Y electrodes formed on the surface of the second substrate facing the first substrate, disposed in pairs between the X electrodes. 
     According to an aspect of the present embodiments, there is provided a PDP including a first substrate and a second substrate bonded to face each other; a plurality of discharge cells disposed between the first and second substrates; a plurality of X electrodes crossing the discharge cells and formed between the first and second substrates; and a plurality of Y electrodes crossing the discharge cells and formed between the first and second substrates, wherein the X electrodes are shared by the discharge cells in the direction perpendicular to the direction in which the X and Y electrodes extend. 
     The width of the X electrodes may be wider than the width of the Y electrodes. 
     The Y electrodes may be adjacent between the discharge cells in the direction perpendicular to the direction in which the X electrodes and the Y electrodes extend. 
     An external light absorbing layer may further be included between the Y electrodes. 
     The X electrodes and Y electrodes include transparent electrodes and bus electrodes, respectively and the shared X electrodes may be bus electrodes. The bus electrodes may be formed of a material that absorbs external light. 
     According to another aspect of the present embodiments, there is provided a PDP including a first substrate and a second substrate bonded to face each other; a plurality of X electrodes formed on the surface of the first substrate facing the second substrate, apart a predetermined distance from each other; and a plurality of Y electrodes formed on the surface of the second substrate facing the first substrate, disposed in pairs between the X electrodes. 
     The width of the X electrodes may be wider than the width of the Y electrodes. 
     An external light absorbing layer may further be included between a pair of the Y electrodes disposed between the X electrodes. 
     The X electrodes and Y electrodes include transparent electrodes and bus electrodes, respectively, and a pair of bus electrodes of Y electrodes may be disposed between the bus electrodes of X electrodes. 
     The width of the bus electrodes of the X electrodes may be wider than the width of the bus electrodes of the Y electrodes. 
     The bus electrodes may be formed of a material that absorbs external light. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and advantages of the present embodiments will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: 
         FIG. 1  is a simplified plan view showing a layout of electrodes of a conventional plasma display panel (PDP); 
         FIG. 2  is a simplified plan view showing an electrode layout of a PDP according to an embodiment; 
         FIG. 3  is a cross sectional view of a PDP according to an embodiment; and 
         FIG. 4  is a plan view showing electrodes of a PDP according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, the present embodiments will be described in detail by explaining exemplary embodiments with reference to attached drawings. 
       FIG. 2  is a simplified plan view showing a disposition of electrodes of a plasma display panel (PDP) according to an embodiment. 
     Referring to  FIG. 2 , in a PDP according to an embodiment, address electrodes which extend in the vertical direction of the paper are disposed so as to be spaced a predetermined distance apart from each other in an A 1 , A 2 , A 3 , . . . order. 
     X electrodes and Y electrodes are disposed to intersect the address electrodes at right angles. First, the X electrodes that extend in the horizontal direction of the paper are disposed parallel to each other and spaced a predetermined distance apart from each other in an X 1 , X 2 , X 3 , . . . , order. A pair of Y electrodes are disposed between and parallel to the X electrodes. However, the Y 1  Y electrode is disposed singularly outside of the X electrodes when starting from a Y electrode according to an embodiment illustrated in  FIG. 2 . A discharge cell is formed where the address electrodes cross X electrodes and Y electrodes. 
     According to an embodiment, a first discharge cell (C 1 ) is formed where the A1 address electrode crosses the Y 1  Y electrode and the X 1  X electrode, and a second discharge cell (C 2 ) is formed where the A1 address electrode crosses the Y 2  Y electrode and the X 1  X electrode. Also, a third discharge cell (C 3 ) is formed where the A 1  address electrode crosses the Y 3  Y electrode and the X 2  X electrode, a fourth discharge cell (C 4 ) is formed where the A1 address electrode crosses the Y 4  Y electrode and the X 2  X electrode, and a fifth discharge cell (C 5 ) is formed where the A1 address electrode crosses the Y 5  Y electrode and the X 3  X electrode. In  FIG. 2 , only 5 discharge cells in the vertical direction of the paper are shown as examples, and other discharge cells are omitted. Regarding the embodiment shown in  FIG. 2 , it is apparent that the discharge cells in the first row are not disposed in the form of a pair of Y electrodes between X electrodes. 
     Likewise, according to a preferred embodiment, contiguous discharge cells disposed in the vertical direction of address electrodes (A 1 , A 2 , A 3 , . . . ) share an X electrode. An example in which a Y electrode is disposed first is shown in  FIG. 2 . however an X electrode can be disposed first. In this case, it is apparent that the X electrode in the first row cannot be shared. 
     In such a structure as above, X electrodes become Common electrodes, and Y electrodes become Scan electrodes. Since a common voltage is applied to the X electrodes, driving pixels are not affected by the fact that the X electrodes are shared by contiguous discharge cells. According to a preferred embodiment, as shown in  FIG. 2 , X and Y electrodes are not adjacent to each other, but rather electrodes of same kind are adjacent between adjacent discharge cells, and thus there is no possibility that cross-talk is generated between contiguous discharge cells. 
       FIG. 3  is a sectional view showing a structure of a PDP according to a preferred embodiment, wherein the electrode structure shown in  FIG. 2  is embodied.  FIG. 4  is a plan view showing the electrode structure of the same. 
     Referring to  FIG. 3 , in a PDP according to a preferred embodiment, a first substrate  10  and a second substrate  20  are disposed to face each other, a discharge gas such as Ne, Xe, and the like is filled between the first and second substrates  10 ,  20  which form a discharge space, and edges of the substrates are bonded together and sealed by a sealing member such as a frit glass (not shown). 
     Barrier ribs  13  are formed between the first substrate  10  and the second substrate  20  and define the space between the first and second substrates  10 ,  20  into a plurality of discharge cells (C). 
     The barrier ribs can be formed of a dielectric commonly used in typical PDPs, using various methods such as screen printing, sand blasting, a dry film method, photolithography, etc. The barrier ribs  13  can be formed in a lattice shape, but are not limited thereto, and can be formed in various shapes such as a honeycomb, a circle, etc. 
     Around a discharge cell (C) defined by the barrier ribs  13 , discharge sustain electrodes such as X electrodes  21  and Y electrodes  22 , and address electrodes  11  are formed so as to cross each other to generate a discharge. According to a preferred embodiment, the address electrodes  11  are disposed on the first substrate, and the X and Y electrodes  21 ,  22 , that is, the discharge sustain electrodes, are formed on the second substrate  20  to intersect the address electrodes  11  and to be parallel to each other. One unit of the discharge cell (C) is formed where the X and Y electrodes  21 ,  22  and the address electrode  11  intersect each other, as shown in  FIG. 2  above. 
     The address electrodes  11  can be formed to be not exposed to the discharge cells. According to a preferred embodiment, a first dielectric layer  12  can be formed to cover the address electrode  11  on the first substrate  10 . The first dielectric layer  12  may be formed to exhibit white color to improve brightness of the entire panel. The address electrode  11  can be formed in a stripe pattern parallel to one side of the first substrate  10 . 
     Pairs of discharge sustain electrodes  21 ,  22  are formed as a pair of an X electrode  21  and a Y electrode  22 . The X electrode  21  and Y electrode  22  extend in a direction substantially perpendicular to the direction in which the address electrode  11  extends. 
     The X electrode  21  and the Y electrode  22  can be formed of transparent electrodes  23  and  25 , respectively, which may be formed of Indium Tin Oxide (ITO) which is a transparent conductor, and bus electrodes  24  and  26 , respectively, which may be formed of highly conductive Ag, Au, or Cu, and are connected to the transparent electrodes  23  and  25  respectively. According to a preferred embodiment, the transparent electrodes  23 ,  25  are formed in an island shape in each discharge cell, and the bus electrodes  24 ,  26  can be formed in a stripe shape substantially perpendicular to the address electrode  11 . A black additive material can be contained in the bus electrodes  24 ,  26  to improve contrast. Black additive materials are not necessarily black, but materials having low reflectivity which can absorb external light may be used. 
     In a preferred embodiment, as shown in  FIG. 4 , the bus electrode  24  of the X electrodes are formed to be wider than the bus electrode  26  of the Y electrodes so that the bus electrode  24  of X electrodes can be shared by the contiguous discharge cells. Therefore, as shown in  FIGS. 3 and 4 , the bus electrode  24  of X electrodes covers edges of the transparent electrodes  23 , each of the transparent electrodes extending to two discharge cells. Forming the bus electrodes  24  of X electrodes widely so that they can be shared by two adjacent discharge cells increases external light absorption, thereby further improving contrast. 
     An external light absorbing member  27  in the form of a black stripe is further formed between the bus electrodes  26  of the Y electrodes to improve contrast. The external light absorbing member  27  can be manufactured using the same material as used in the bus electrodes  24 ,  26  at the same time, thus allowing a process for forming the external absorbing member  27  to be omitted and reducing material costs and manufacturing time. However, the material for the external light absorbing member is not limited thereto, and can be a black insulator. 
     A second dielectric layer  28  is formed on the second substrate  20  to cover the X electrodes  21  and the Y electrodes  22 , and a protecting layer  29 , including MgO, for example, which can also function substantially as a cathode, can be formed on the second dielectric layer. 
     A phosphor layer  14  can be formed on at least one side of the discharge cell (C). According to a preferred embodiment, the phosphor layer may be formed on the first dielectric layer  12  of the first substrate  10  and the side wall of the barrier ribs  13 . The phosphor layer  14  can be formed as a red (R), green (G), or blue (B) layer according to each discharge cell defined by the barrier ribs  13 . 
     According to the present embodiments, cross-talk is prevented by avoiding adjoining of an X electrode with a Y electrode between adjacent discharge cells, through sharing an X electrode between adjacent discharge cells. In addition, by forming X electrodes more widely than Y electrodes, contrast can be improved and the process can be simplified. 
     While the present embodiments have been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present embodiments as defined by the following claims.