Patent Publication Number: US-2006001354-A1

Title: Transparent electrode for plasma display panel

Description:
BACKGROUND OF INVENTION  
      1. Field of the Invention  
      The present invention relates to a kind of plasma display panel, more particularly a design of transparent electrode on the front substrate of the plasma display panel.  
      2. Description of the Prior Art  
      A conventional plasma display panel (PDP) typically comprises a front plate and a rear plate. The front plate comprises a glass substrate disposed thereon a plurality of paired and parallelly arranged scan electrodes and sustain electrodes and black stripes disposed on the side of each pair of scan electrode and sustain electrode and coated with in sequence a dielectric and an electrode protection layer thereon.  
      The rear plate comprises a glass substrate disposed with a plurality of parallelly arranged address electrodes coated with a dielectric layer, which has patterned barrier ribs formed thereon. The discharge cells defined between barrier ribs are deposited with three primary color phosphors (red, green and blue) in patterned distribution. The rear plate is aligned and sealed to the side surface of front plate. At the time of sealing, inert gases such as neon (Ne) and xenon (Xe) are charged and the address electrodes are arranged orthogonal to the paired scan electrode and sustain electrode of front plate so that a discharge space is formed at the place where the paired scan electrode and sustain electrode alternately intersects the address electrode, which corresponds to the discharge cell containing one primary color phosphor on the inner wall of barrier rib. As such, when a voltage is applied to the PDP, the inert gases therein are ionized to generate plasma and give off ultraviolet rays to excite the red, green and blue phosphors between the barrier ribs, which in turn emit visible red, green and blue lights, and under the driving of predetermined circuit, produce full-color images of different levels.  
      In the PDP described above, the plurality of scan electrodes and sustain electrodes are transparent electrodes made of light-transmitting and conductive material, such as ITO or SnO 2  to keep them from blocking the emission of plasma-excited rays. Also in light that large amount of heat is generated in the process of plasma generation that tends to raise the resistance of transparent electrodes and affect the stability of voltage for gas discharge, a straight metal bus electrode with width smaller than the transparent electrode is added to each transparent electrode as an auxiliary to enhance its conductivity.  
      In the aforementioned PDP structure, the transparent electrodes disposed on the front glass substrate provides light transmission and conductivity to create electrical fields with the address electrode of rear plate above and below the discharge cells deposited with red, green or blue phosphor when voltage is applied to the PDP, so that the ionized inert gases in the discharge cell would generate plasma to excite the phosphors to emit red, green or blue lights, which shine through the transparent electrodes. But the straight-strip design of the transparent electrodes tends to play down its field effect in discharge cells, thus affecting the generation of plasma to excite the phosphors to glow.  
     SUMMARY OF INVENTION  
      The primary object of the present invention is to provide a kind of transparent electrode for plasma display panel to improve its illumination efficiency.  
      To achieve the aforesaid object, the paired transparent electrodes X and Y parallelly arranged and spaced part on the front glass substrate respectively have an extension member Xn and an extension member Yn projected from the opposing side of a strip-shaped base corresponding to each discharge cell of the panel. The extension member Xn and extension member Yn are asymmetrical in shape and spaced apart from each other.  
      The asymmetrical shape design of the extension member Xn and extension member Yn of the paired transparent electrodes is matched with the address electrode on rear substrate plate such that when voltage is applied to the PDP, the field effect in individual discharge cells may be converged to enhance the generation of plasma to excite the phosphors to glow. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The details of the present invention will be more readily understood from a detailed description of the preferred embodiments taken in conjunction with the following figures.  
       FIG. 1  is a schematic diagram of the first embodiment according to the invention.  
       FIG. 2  is a schematic diagram of the first embodiment according to the invention showing unequal distance between extension members X 1  and extension members Y 1 .  
       FIG. 3  is a schematic diagram of the second embodiment according to the invention.  
       FIG. 4  is a schematic diagram of the second embodiment according to the invention showing unequal distance between extension members X 2  and extension members Y 2 .  
       FIG. 5  is a schematic diagram of the third embodiment according to the invention.  
       FIG. 6  is a schematic diagram of the third embodiment according to the invention showing unequal distance between extension members X 3  and extension members Y 3 .  
       FIG. 7  is a schematic diagram of the fourth embodiment according to the invention.  
       FIG. 8  is a schematic diagram of the fourth embodiment according to the invention showing unequal distance between extension members X 4  and extension members Y 4 .  
       FIG. 9  is a schematic diagram of the fifth embodiment according to the invention.  
       FIG. 10  is a schematic diagram of the fifth embodiment according to the invention showing unequal distance between extension members X 5  and extension members Y 5 .  
       FIG. 11  is a schematic diagram of the sixth embodiment according to the invention.  
       FIG. 12  is a schematic diagram of the sixth embodiment according to the invention showing unequal distance between extension members X 6  and extension members Y 6 .  
       FIG. 13  is a schematic diagram of the seventh embodiment according to the invention showing unequal distance between extension members X 7  and extension members Y 7 .  
       FIG. 14  is a schematic diagram of the eighth embodiment according to the invention showing unequal distance between extension members X 8  and extension members Y 8 .  
       FIG. 15  is a schematic diagram of the ninth embodiment according to the invention showing unequal distance between extension members X 9  and extension members Y 9 .  
       FIG. 16  is a schematic diagram of the tenth embodiment according to the invention showing unequal distance between extension members X 10  and extension members Y 10 . 
    
    
     DETAILED DESCRIPTION  
       FIG. 1  illustrates an embodiment of the transparent electrode for plasma display panel according to the present invention. As shown, the transparent electrodes are in pairs and formed parallel and spaced apart on the glass substrate of front plate of PDP. The paired transparent electrodes X and Y each have a strip-shaped base ( 10 ,  20 ) of predefined width, and an extension member X 1  and an extension member Y 1  are projected from the opposing side of the base corresponding to each discharge cell of the PDP. The extension member X 1  and extension member Y 1  are asymmetrical in shape and spaced apart from each other.  
      The shapes of extension member X 1  and extension member Y 1  may have at least the following designs as illustrated in the embodiments.  
      In the first embodiment of the present invention, either extension member X 1  or extension member Y 1  is in T-shaped and the other is square-shaped. As shown in  FIG. 1 , extension member X 1  is T-shaped and extension member Y 1  is square-shaped, while the broader end of the T-shaped extension member X 1  faces extension member Y 1  and has the same width as that of the opposing end of extension member Y 1 , and the distances D between extension member X 1  and extension member Y 1  of each paired transparent electrodes X and Y corresponding to the red, green and blue discharge cells (R, G, B) in each pixel of the PDP are equal. Or as shown in  FIG. 2 , the distances D 1 , D 2  and D 3  between extension member X 1  and extension member Y 1  of each paired transparent electrodes X and Y corresponding to the red, green and blue discharge cells (R, G, B) in each pixel of the PDP are unequal, wherein the distance D 1  corresponding to red discharge cell (R) is greater than the distance D 2  corresponding to green discharge cell (G), and the distance D 2  corresponding to green discharge cell (G) is greater than the distance D 3  corresponding to blue discharge cell (B).  
      In the second embodiment of the invention, either extension member X 2  or extension member Y 2  is in T-shaped and the other is square-shaped and flat ended with a widening triangle. As shown in  FIG. 3 , the extension member X 2  is T-shaped and extension member Y 2  is square-shaped and flat ended with a widening triangle, while the broader end of the T-shaped extension member X 2  faces the broader end of the widening triangle of extension member Y 2 , and the distances D between extension member X 2  and extension member Y 2  of each paired transparent electrodes X and Y corresponding to the red, green and blue discharge cells (R, G, B) in each pixel of the PDP are equal. Or as shown in  FIG. 4 , the distances D 1 , D 2  and D 3  between extension member X 2  and extension member Y 2  of each paired transparent electrodes X and Y corresponding to the red, green and blue discharge cells (R, G, B) in each pixel of the PDP are unequal, wherein the distance D 1  corresponding to red discharge cell (R) is greater than the distance D 2  corresponding to green discharge cell (G), and the distance D 2  corresponding to green discharge cell (G) is greater than the distance D 3  corresponding to blue discharge cell (B).  
      In the third embodiment of the invention, either extension member X 3  or extension member Y 3  is in T-shaped and the other is in trapezoid shape with its broader end facing the broader end of T-shaped configuration. As shown in  FIG. 5 , the extension member X 3  is a T-shaped protrusion and extension member Y 3  is a trapezoid protrusion, while the broader ends of the T-shaped protrusion and the trapezoid protrusion face each other, and the distances D between extension member X 3  and extension member Y 3  of each paired transparent electrodes X and Y corresponding to the red, green and blue discharge cells (R, G, B) in each pixel of the PDP are equal. Or as shown in  FIG. 6 , the distances D 1 , D 2  and D 3  between extension member X 3  and extension member Y 3  of each paired transparent electrodes X and Y corresponding to the red, green and blue discharge cells (R, G, B) in each pixel of the PDP are unequal, wherein the distance D 1  corresponding to red discharge cell (R) is greater than the distance D 2  corresponding to green discharge cell (G), and the distance D 2  corresponding to green discharge cell (G) is greater than the distance D 3  corresponding to blue discharge cell (B).  
      In the fourth embodiment of the invention, either extension member X 4  or extension member Y 4  is in T-shaped and the other is a square-shaped protrusion with width slightly greater than the broader end of the T-shaped configuration and having both side ends opposing extension member X 4  cut. As shown in  FIG. 7 , the extension member X 4  has a T-shaped configuration and the extension member Y 4  is a square-shaped protrusion with width slightly greater than the broader end of the T-shaped configuration and its both side ends opposing extension member X 4  are cut, so that the end of extension member Y 4  and the opposing end of extension member X 4  are equal in width. In addition, the distances D between extension member X 4  and extension member Y 4  of each paired transparent electrodes X and Y corresponding to the red, green and blue discharge cells (R, G, B) in each pixel of the PDP are equal. Or as shown in  FIG. 8 , the distances D 1 , D 2  and D 3  between extension member X 4  and extension member Y 4  of each paired transparent electrodes X and Y corresponding to the red, green and blue discharge cells (R, G B) in each pixel of the PDP are unequal, wherein the distance D 1  corresponding to red discharge cell (R) is greater than the distance D 2  corresponding to green discharge cell (G), and the distance D 2  corresponding to green discharge cell (G) is greater than the distance D 3  corresponding to blue discharge cell (B).  
      In the fifth embodiment of the invention, either extension member X 5  or extension member Y 5  is in T-shaped and the other is in trapezoid shape with its narrow end facing the broader end of T-shaped configuration. As shown in  FIG. 9 , the extension member X 5  is a T-shaped protrusion and extension member Y 5  is a trapezoid protrusion with its narrow end facing the broader end of T-shaped extension member X 5  and the width of the narrow end being equal to the opposite broader end of extension member X 5 . In addition, the distances D between extension member X 5  and extension member Y 5  of each paired transparent electrodes X and Y corresponding to the red, green and blue discharge cells (R, G, B) in each pixel of the PDP are equal. Or as shown in  FIG. 10 , the distances D 1 , D 2  and D 3  between extension member X 5  and extension member Y 5  of each paired transparent electrodes X and Y corresponding to the red, green and blue discharge cells (R, G, B) in each pixel of the PDP are unequal, wherein the distance D 1  corresponding to red discharge cell (R) is greater than the distance D 2  corresponding to green discharge cell (G), and the distance D 2  corresponding to green discharge cell (G) is greater than the distance D 3  corresponding to blue discharge cell (B).  
      In the sixth embodiment of the invention, either extension member X 6  or extension member Y 6  is in T-shaped and the other is a square-shaped protrusion with width comparable to the broader end of the T-shaped configuration and having both side ends nearing its base cut. As shown in  FIG. 11 , the extension member X 6  has a T-shaped configuration and the extension member Y 6  is a square-shaped protrusion with width comparable to the broader end of the T-shaped configuration and its both side ends nearing the base  20  are cut. In addition, the distances D between extension member X 6  and extension member Y 6  of each paired transparent electrodes X and Y corresponding to the red, green and blue discharge cells (R, G, B) in each pixel of the PDP are equal. Or as shown in  FIG. 12 , the distances D 1 , D 2  and D 3  between extension member X 6  and extension member Y 6  of each paired transparent electrodes X and Y corresponding to the red, green and blue discharge cells (R, G, B) in each pixel of the PDP are unequal, wherein the distance D 1  corresponding to red discharge cell (R) is greater than the distance D 2  corresponding to green discharge cell (G), and the distance D 2  corresponding to green discharge cell (G) is greater than the distance D 3  corresponding to blue discharge cell (B).  
      In the seventh embodiment of the invention, extension members X 7  and Y 7  are both in I-shaped and both having a broader bottom portion adjacent to the strip-shaped base ( 10  or  20 ), a neck portion extending out from the broader bottom portion, and a broader head portion which is substantially parallel to the strip-shaped bases ( 10  and  20 ). However, either one of the extension members X 7  or Y 7  has its neck portion being narrowed in middle, while the other one has its neck portion being widened in middle. As shown in  FIG. 13 , the extension member X 7  is in the I-shaped configuration having a neck portion being narrowed in middle, while the extension member Y 7  is also in the I-shaped configuration having a neck portion being widened in middle. In addition, the distances D 1 , D 2  and D 3  between extension member X 7  and extension member Y 7  of each paired transparent electrodes X and Y corresponding to the red, green and blue discharge cells (R, G, B) in each pixel of the PDP are unequal, wherein the distance D 1  corresponding to red discharge cell (R) is greater than the distance D 2  corresponding to green discharge cell (G), and the distance D 2  corresponding to green discharge cell (G) is greater than the distance D 3  corresponding to blue discharge cell (B).  
      In the eighth embodiment of the invention, extension members X 8  and Y 8  are both in I-shaped and both having a broader bottom portion adjacent to the strip-shaped base ( 10  or  20 ), a neck portion extending out from the broader bottom portion, and a broader head portion which is substantially parallel to the strip-shaped bases ( 10  and  20 ). However, either one of the extension members X 8  or Y 8  has its broader head portion being a widening triangle, while the other one has its broader head portion being an elongated rectangular strip. As shown in  FIG. 14 , the extension member X 8  is in the I-shaped configuration having its broader head portion being an elongated rectangular strip, while the extension member Y 8  is also in the I-shaped configuration having its broader head portion being a widening triangle. In addition, the distances D 1 , D 2  and D 3  between extension member X 8  and extension member Y 8  of each paired transparent electrodes X and Y corresponding to the red, green and blue discharge cells (R, G, B) in each pixel of the PDP are unequal, wherein the distance D 1  corresponding to red discharge cell (R) is greater than the distance D 2  corresponding to green discharge cell (G), and the distance D 2  corresponding to green discharge cell (G) is greater than the distance D 3  corresponding to blue discharge cell (B).  
      In the ninth embodiment of the invention, either extension member X 9  or extension member Y 9  is in T-shaped and the other is in trapezoid shape with its narrow end facing the broader end of T-shaped configuration. In addition, a semicircular opening is formed on the trapezoid shaped extension member. As shown in  FIG. 15 , the extension member X 9  is in the T-shaped configuration having its broader end portion facing the extension member Y 9 , while the extension member Y 9  is in trapezoid shape with its narrow end facing the broader end of T-shaped extension member X 9 . A semicircular opening  21  is formed on the trapezoid shaped extension member Y 9 . In addition, the distances D 1 , D 2  and D 3  between extension member X 9  and extension member Y 9  of each paired transparent electrodes X and Y corresponding to the red, green and blue discharge cells (R, G, B) in each pixel of the PDP are unequal, wherein the distance D 1  corresponding to red discharge cell (R) is greater than the distance D 2  corresponding to green discharge cell (G), and the distance D 2  corresponding to green discharge cell (G) is greater than the distance D 3  corresponding to blue discharge cell (B).  
      In the tenth embodiment of the invention, either extension member X 10  or extension member Y 10  is in T-shaped and the other is a wide strip extending parallel to the strip-shaped base ( 10  or  20 ). A plurality of round openings are formed on the wide strip shaped extension member. Each of the T-shaped extension members is apart from and facing the middle of two adjacent openings. As shown in  FIG. 16 , the extension member X 10  is in the T-shaped configuration having its broader end portion facing the extension member Y 10 , while the extension member Y 10  is a wide strip extending parallel to the strip-shaped base ( 10  or  20 ) and having a plurality of round openings  22  formed thereon. Each T-shaped extension member X 10  is apart from and facing the middle of two adjacent openings  22  of the extension member Y 10 . In addition, the distances D 1 , D 2  and D 3  between extension member X 10  and extension member Y 10  of each paired transparent electrodes X and Y corresponding to the red, green and blue discharge cells (R, G, B) in each pixel of the PDP are unequal, wherein the distance D 1  corresponding to red discharge cell (R) is greater than the distance D 2  corresponding to green discharge cell (G), and the distance D 2  corresponding to green discharge cell (G) is greater than the distance D 3  corresponding to blue discharge cell (B).  
      The designs disclosed above aim to render extension member Xn and extension member Yn of each paired electrodes in the discharge cell asymmetrical in shape and correspond to the address electrode on rear plate so that when voltage is applied to the PDP, the field effects in individual discharge cell are converged to enhance the illumination efficiency of phosphors as excited by the plasma and increase the luminance of the PDP. Also in light of the different illumination efficiency of three primary color phosphors, the distances between extension member Xn and extension member Yn corresponding to each set of red, green and blue discharge cells are designed to be unequal to enhance the color temperature effect of the panel.  
      Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teachings of the invention. Accordingly, that above disclosure should be construed as limited only by the metes and bounds of the appended claims.