Abstract:
A plasma display panel (PDP) having electrodes with an improved structure to prevent cutting defects thereof, the PDP including: a pair of substrates including display regions displaying images and non-display regions that do not display images, wherein the substrates are arranged to face each other and spaced apart from each other; barrier ribs corresponding to the display regions and defining discharge cells where a gas discharge is generated, the barrier ribs being arranged between the substrates; a phosphor layer respectively disposed in the discharge cells; a plurality of electrodes, each including an electrode portion provided in the display regions of the substrates, an oblique line portion provided at a side of the non-display regions and electrically connected to the electrode portion, and a terminal portion electrically connected to the oblique line portion, the terminal portion including a groove formed therein; and a dielectric layer formed on the substrates.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of Korean Application No. 2007-42756, filed May 2, 2007 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    Aspects of the present invention relate to a plasma display panel, and more particularly, to a plasma display panel having an improved structure to prevent cutting defects of electrodes. 
         [0004]    2. Description of the Related Art 
         [0005]    A plasma display panel is a flat panel display that reproduces images using gas discharges. Since the plasma display panel has a thin structure with a large screen that displays high quality images, much research has been conducted thereon. 
         [0006]    The plasma display panel includes a first substrate and a second substrate, barrier ribs arranged between the first and second substrates; a discharge gas, a phosphor layer, and electrodes to which a voltage is applied. The first and second substrates face each other and are spaced apart. The barrier ribs define discharge cells in which gas discharges are generated. The discharge gas is filled in the discharge cells to generate the gas discharges. The phosphor layer is coated on surfaces of the discharge cells. The gas discharges are generated in the discharge cells by a direct current or alternate current voltage applied between the electrodes, and ultraviolet rays emitted from the discharge gas excites the phosphor layer to emit visible light, thereby realizing images. 
         [0007]    The electrodes in the plasma display panel include sustaining electrodes formed in the first substrate and address electrodes formed in the second substrate. The sustaining electrodes include common electrodes and scanning electrodes. The address electrodes generate an address discharge according to address voltages applied between the scanning electrodes and the address electrodes. 
         [0008]      FIG. 1  is a plane view illustrating electrodes and contact terminals of a conventional plasma display panel. Referring to  FIG. 1 , the sustaining electrodes or the address electrodes extend toward a terminal region C 1  outside a display region A 1 , and are connected to a signal transfer unit  120  (such as a flexible printed circuit or a chip on film) in the terminal region C 1  to receive driving voltages from a driving circuit substrate (not shown). A connection region B 1  is formed between the display region A 1  and the terminal region C 1 . 
         [0009]    Accordingly, the sustaining electrodes include electrode portions  111  formed at a pitch P 1  in the display region A 1 , terminal portions  113  formed at a pitch P 2  shorter than the pitch P 1 , and oblique line portions  112  formed in the connection region B 1  to connect the electrode portions  111  to the terminal portions  113  in symmetric oblique lines at a gradually reducing pitch. 
         [0010]    As described above, the pitch P 2  between the electrodes in the terminal portions  113  is reduced because the signal transfer unit  120  is continuously disposed at one edge of the first or second substrate  110  and, thus, it is not possible to precisely connect the signal transfer unit  120  to the terminal portion  113  of the electrodes. In other words, the signal transfer unit  120  must be mounted in the terminal region C 1  while being divided into multiple regions. Furthermore, a spare space to avoid interactive interference between the multiple regions of the signal transfer unit  120  is required, such that the pitch P 2  between the electrodes in the terminal portion  113  is reduced. 
         [0011]    However, when the number of the electrodes including the oblique line portions  112  is increased in order to extend the display region A 1  or to realize high quality images in order to efficiently use the first or second substrate  110 , the pitch between the electrodes in the portion of the oblique line portions  112  near the terminal portion  113  is reduced even more. 
         [0012]    Thus, for the above described reasons, the designing of electrodes between the oblique line portions  112  and the terminal portions  113  is difficult as defects (such as a short circuit of the oblique line portions  112 ) may be generated during the manufacturing of the electrodes, particularly during an exposure and developing process. Also, when cutting the terminal portions  113 , the terminal portions  113  may not be properly cut off, thereby creating the possibility of generating cutting defects. 
         [0013]    As described above, it is difficult to extend the display region A 1 . Accordingly, the substrates cannot be efficiently used and it is difficult to manufacture a plasma display panel for realizing high quality images according to the conventional art. 
       SUMMARY OF THE INVENTION 
       [0014]    Aspects of the present invention provide a plasma display panel including electrodes having an improved structure to prevent cutting defects thereof. 
         [0015]    According to an aspect of the present invention, there is provided a plasma display panel including: a first substrate and a second substrate facing each other and spaced apart from each other, the first substrate including display regions that display images and non-display regions that do not display images; barrier ribs corresponding to the display regions and defining discharge cells where a gas discharge is generated, wherein the barrier ribs are arranged between the first substrate and the second substrate; a phosphor layer respectively disposed in each of the discharge cells; a plurality of electrodes, each including an electrode portion provided in at least one of the display regions of the first substrate, an oblique line portion provided at a side of the non-display regions and electrically connected to the electrode portion, and a terminal portion electrically connected to the oblique line portion, and including a groove formed therein; and a dielectric layer formed on the substrates. 
         [0016]    The groove may be provided on a cut off area of each terminal portion from which the terminal portions are cut. 
         [0017]    The pitch between the terminal portions may be smaller than the pitch between the electrode portions. 
         [0018]    The second substrate may include sustaining electrodes to generate a gas discharge in the discharge cells and including common electrodes and scanning electrodes. 
         [0019]    The common electrodes may be extended in a first direction, and the scanning electrodes may be extended in a second direction that crosses the first direction. 
         [0020]    The common electrodes and the scanning electrodes may be extended substantially parallel to each other, and the plurality of electrodes may be address electrodes extended to cross the direction in which the common electrodes and the scanning electrodes are extended. 
         [0021]    According to another aspect of the present invention, there is provided a plasma display panel including: a first substrate and a second substrate facing each other; light emitting cells partitioned by barrier ribs arranged in display regions of the first substrate and the second substrate; a phosphor respectively coated in the light emitting cells; a discharge gas sealed in the light emitting cells; sustaining electrodes extending across the light emitting cells in a first direction; address electrodes extending across the light emitting cells in a second direction that crosses the first direction; at least one short bar provided at a side of the address electrodes and extending in a third direction that crosses second direction; a first dielectric layer to cover the sustaining electrodes; and a second dielectric layer to cover the address electrodes, wherein the side of the address electrodes on which the short bar is provided has a smaller width than another side of the address electrodes. 
         [0022]    Each address electrode may include: an electrode portion located in the display region; a terminal portion located in a terminal region outside of the display region and connected to the short bar; and an oblique line portion connecting the electrode portion and the terminal portion, wherein a first area of the terminal portion has a smaller width than a second area of the terminal portion. 
         [0023]    The first area of the terminal portion may be a cut off area of the address electrode from which the address electrode is cut. 
         [0024]    The first area may be provided closer to the short bar than the second area. 
         [0025]    According to yet another aspect of the present invention, there is provided a substrate included in a plasma display panel, the substrate including: display regions that display images; non-display regions that do not display images; and a plurality of electrodes, each comprising an electrode portion provided in at least one of the display regions, an oblique line portion provided at a side of the non-display regions and electrically connected to the electrode portions, and a terminal portion electrically connected to the oblique line portions and including a groove formed therein. 
         [0026]    According to still another aspect of the present invention, there is provided an electrode extending across display and non-display regions of a substrate on a plasma display panel, the electrode including: an electrode portion provided in at least one of the display regions; an oblique line portion provided at a side of the non-display regions and electrically connected to the electrode portion; and a terminal portion electrically connected to the oblique line portion and including a groove formed therein. 
         [0027]    Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]    These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
           [0029]      FIG. 1  is a plane view illustrating electrodes and contact terminals of a conventional plasma display panel; 
           [0030]      FIG. 2  is a partial separate perspective view illustrating a plasma display panel according to an embodiment of the present invention; 
           [0031]      FIG. 3  is a partial separate perspective view illustrating electrodes and contact terminals of the plasma display panel of  FIG. 2 ; and 
           [0032]      FIG. 4  is a schematic view showing a cutting process of a short bar and electrodes of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0033]    Reference will now be made in detail to the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures. 
         [0034]      FIG. 2  is a partial separate perspective view illustrating a plasma display panel  200  according to an embodiment of the present invention. Referring to  FIG. 2 , the plasma display panel  200  includes a first substrate  210 , a second substrate  220 , barrier ribs  280 , a discharge gas (not shown), a phosphor layer  285 , and electrodes  230  and  260  to which a voltage is applied. The first substrate  210  and the second substrate  220  are spaced apart from each other and disposed parallel to each other. The barrier ribs  280  are provided between the first substrate  210  and the second substrate  220 , and define discharge cells  290  in which a gas discharge is generated. The discharge gas is filled in the discharge cells  290  to generate the gas discharge. The phosphor layer  285  is coated on surfaces in the discharge cells  290 . The first substrate  210  is transparent and may be formed of glass. 
         [0035]    A pair of sustaining electrodes  230  including a common electrode  231  and a scanning electrode  232  is disposed on the first substrate  210 . The common electrode  231  includes a transparent electrode  231   a  and a bus electrode  231   b . Similarly, the scanning electrode  232  also includes a transparent electrode  232   a  and a bus electrode  232   b . However, aspects of the present invention are not limited thereto. For example, the common electrode  231  and the scanning electrode  232  may include only the bus electrodes  231   b  and  232   b  without the transparent electrodes  231   a  and  232   a . When the common electrode  231  and the scanning electrode  232  include only the bus electrodes  231   b  and  232   b , the common electrode  231  and the scanning electrode  232  may be formed as a minute bus electrode group. Furthermore, while the sustaining electrode pair  230  in the current embodiment of is disposed on the first substrate  210 , it is understood that the electrode pair  230  may also be spaced apart from the first substrate  210 . 
         [0036]    The transparent electrodes  231   a  and  232   a  are separated for each discharge cell  290  and bonded to the bus electrodes  231   b  and  232   b . Furthermore, the transparent electrodes  231   a  and  232   a  may be formed of, for example, indium tin oxide (ITO). While the transparent electrodes  231   a  and  232   a  in the current embodiment are separated for each discharge cell  290 , aspects of the present invention are not limited thereto. For example, the transparent electrodes  231   a  and  232   a  may be provided continuously across the discharge cells  290 . 
         [0037]    The bus electrodes  231   b  and  232   b  may be provided above the barrier ribs  280  and may be spaced apart from upper ends of the barrier ribs  280 . Also, a space between a pair of the bus electrodes  231   b  and  232   b  and another neighboring pair of the bus electrodes  231   b  and  232   b  corresponds to a non-discharge region  211 . Although not shown, a black mattress layer may be formed in the non-discharge region  211 . 
         [0038]    A first dielectric layer  240  is disposed on the first substrate  210  to cover the sustaining electrode pair  230 . Thus, the first dielectric layer  240  prevents direct conduction between neighboring common electrodes  231  and scanning electrodes  232  during a discharge, prevents charge particles from directly colliding with the sustaining electrode pair  230  and damaging the sustaining electrode pair  230 , and accumulates wall charges by inducing charged particles. A dielectric material (such as PbO, B 2 O 3 , SiO 2 , etc.) is used for the dielectric layer  240 . 
         [0039]    A protection layer  250  formed of MgO and/or the like is formed under the first dielectric layer  240 . The protection layer  250  prevents the sustaining electrode pairs  230  from being damaged by sputtering of plasma particles, and emits a large amount of secondary electrons to reduce discharge voltages. 
         [0040]    Address electrodes  260  are provided on the second substrate  220 . Together with the scanning electrodes  232 , the address electrodes  260  perform an address discharge. The address electrodes  260  generate an address discharge in order to make a main discharge between the scanning electrode  232  and the common electrode  231  take place more easily, and more specifically, to reduce the voltage for generating the main discharge. The structure of end portions of the address electrodes  260  will be described in more detail with reference to  FIG. 3 . A second dielectric layer  270  is provided on the address electrodes  260 , and the second dielectric layer  270  protects the address electrodes  260 . 
         [0041]    Although the address electrodes  260  and the second dielectric layer  270  are included in the plasma display panel  200  according to the illustrated embodiment, aspects of the present invention are not limited thereto. For example, the plasma display panel  200  may not include the address electrodes  260  and the second dielectric layer  270 . That is, when the address electrodes  260  are not included in the plasma display panel  200 , a voltage for selecting the discharge cells  290  can be applied between the common electrodes  231  and the scanning electrodes  232  by arranging the common electrode  231  and the scanning electrode  232  to cross each other. 
         [0042]    The barrier ribs  280  are provided on the second dielectric layer  270  to prevent electrical and optical cross talk between discharge cells  290 . The barrier ribs  280  are provided such that a cross-section of the discharge cells  290  is a quadrangle, although aspects of the present invention are not limited thereto. For example, the cross-section may have various other shapes (such as a triangular shape, an pentagonal shape, an oval shape, etc.). 
         [0043]    The phosphor layer  285  includes components receiving ultraviolet rays to emit visible light. Specifically, a red phosphor layer formed in red light emitting discharge cells includes a phosphor such as Y(V,P)O4:Eu or the like, a green phosphor layer formed in green light emitting discharge cells includes a phosphor such as Zn 2 SiO 4 :Mn or the like, and a blue phosphor layer formed in blue light emitting discharge cells includes a phosphor such as BAM:Eu or the like. 
         [0044]    After sealing the first substrate  210  and the second substrate  220 , the inner space of the assembled plasma display panel  200  is filled with air. Thus, the air in the assembled plasma display panel  200  is completely discharged to replace the air with an appropriate discharge gas to improve the discharge efficiency. A mixed gas (such as Ne—Xe, He—Xe, He—Ne—Xe, etc.) can be used as the discharge gas. 
         [0045]      FIG. 3  is a partial separate perspective view illustrating electrodes and contact terminals of the plasma display panel  200  of  FIG. 2 . Referring to  FIG. 3 , the first substrate  210  or the second substrate  220  includes a display region A 2  and non-display regions B 2  and C 2 . The non-display regions B 2  and C 2  include a terminal region C 2  provided on the outermost side of the substrate  210  or  220  and connected to electrodes  230  or  260  and external terminals, and a connection region B 2  provided between the display region A 2  and the terminal region C 2 . 
         [0046]    The electrodes  230  or  260  (sustaining electrodes  230  or address electrodes  260  depending on the substrate  210  or  220 ) are provided in the divided regions A 2  through C 2  (specifically, from the display region A 2 , passing the connection region B 2 , and extending to the terminal region C 2 ). Furthermore, the electrodes  230  or  260  are electrically connected to wiring portions  321  of a signal transfer unit  320  (such as a flexible printed circuit or a chip on film). 
         [0047]    In detail, the electrodes  230  or  260  are arranged at predetermined intervals on the substrate  210  or  220 . The electrodes  230  or the  260  include electrode portions  311  provided in the display region A 2 , oblique line portions  312  provided in the connection region B 2 , and terminal portions  313  provided in the terminal region C 2 . The electrode portions  311 , the oblique line portions  312 , and the terminal portions  313  of the electrodes  230  or  260  are provided as a single body on the same plane of the substrates  210  and  220 . 
         [0048]    In other words, all of the electrode portions  311 , the oblique line portions  312 , and the terminal portions  313  of the electrodes  230  or  260  are provided at the same time by pattern printing. The oblique line portions  312  of the electrodes  230  or  260  are arranged symmetrically to the left and to the right, as illustrated in  FIG. 3 . 
         [0049]    Also, the pitch between each of the terminal portions  313  of the electrodes  230  or  260  is narrower than the pitch between each of the electrode portions  311 . Thus, a spare space is provided on the substrate  210  or  220  and the signal transfer units  320  can be spaced apart from each other, thereby preventing interference between the signal transfer units  320 . 
         [0050]    Here, grooves  313   a  are provided in the terminal portions  313 . In detail, when manufacturing a plasma display panel  200  according to the conventional art, terminal portions are not cut off properly, resulting in cutting defects. In contrast, according to aspects of the present invention, a groove  313   a  is provided in a portion of each of the terminal portions  313  so that the terminal portions  313  can be cut off easily. 
         [0051]    As illustrated in  FIG. 3 , a width tb of the groove  313   a  of the terminal portions  313  is narrower than a width ta of the rest of the terminal portions  313 . Also, a short bar  330  is provided on the outer ring of the terminal portions  313  to cross the extension direction of the electrodes  230  or  260 . The electrodes  230  or  260  and the short bar  330  may be provided as a single body and can be separated later in an additional cutting process. As the groove  313   a  of each terminal portion  313  is cut off, the electrodes  230  or  260  and the short bar  330  can be cut off easily. 
         [0052]    Thus, the electrodes  230  or  260  and the short bar  330  are spaced apart in predetermined intervals from each other, so that the occurrence of a short circuit therebetween can be prevented. The short bar  330  connects the electrodes  230  or  260  so that an aging process can be performed more easily, and also protects the terminal portions  313  of the electrodes  230  or  260  during a forming process of barrier ribs. 
         [0053]    Meanwhile, a dielectric layer  240  or  270  is coated on the substrate  210  or  220  to cover at least a portion of the terminal portions  313  and the oblique line portions  312  of the electrodes  230  or  260 . The dielectric layer  240  or  270  includes a display region A 2  and a connection region B 2 , although aspects of the present invention are not limited thereto. For example, the dielectric layer  240  or  270  may be extended to the terminal region C 2 . 
         [0054]      FIG. 4  is a schematic view showing a cutting process of the short bar  330  and the electrodes  230  or  260  of  FIG. 3 . Referring to  FIG. 4 , the short bar  330  is provided as a single body with the electrodes  230  or  260  on the substrate  210  or  220 , and may be, for example, formed together with the electrodes  230  or  260 . 
         [0055]    The short bar  330  and the electrodes  230  or  260  provided as a single body are separated by an additional cutting process when the aging process is completed. The cutting process can be, as illustrated in  FIG. 4 , performed by irradiating a laser beam onto the groove  313   a  of the electrodes  230  or  260  to cut the irradiated end portions. Accordingly, the electrodes  230  or  260  and the short bar  330  are cut along a cross-section thereof. 
         [0056]    Here, the width of the groove  313   a  of the terminal portions  313  is narrower than the rest of the terminal portions  313 . Thus, time and cost can be reduced in the cutting process using laser irradiation. Also, cutting defects are reduced, thereby increasing product reliability. 
         [0057]    Hereinafter, the operation of the PDP  200  according to an embodiment of the present invention will be described in detail. First, when a voltage is applied from an external power supply to the signal transfer unit  320 , the terminal portions  313 , the oblique line portions  312 , and the electrode portions  311 , sequentially, an address discharge is generated by the address electrodes  260  and the scanning electrode  232 , and a sustaining discharge is generated by the scanning electrode  232  and the common electrode  231 . As the energy potential of the discharge gas that is excited during the sustaining discharge is lowered, ultraviolet rays are emitted. The ultraviolet ray excites a phosphor of the phosphor layer  285  coated in the discharge cells  290 . Furthermore, as the energy potential of the excited phosphor is lowered, visible light is emitted. The emitted visible light is projected to the first substrate  210  and emitted to the outside, forming an image that a user can recognize. 
         [0058]    According to aspects of the present invention, cutting defects of electrodes in a plasma display panel can be prevented. 
         [0059]    Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.