Abstract:
A plasma display panel for improving a color coordinates correction and a color temperature is disclosed. In the plasma display panel, a vertical barrier rib separates red, green and blue discharge cells from each other in a longitudinal direction. A horizontal barrier rib is provided between the vertical barrier ribs to separate the red, green and blue discharge cells from each other in a wide direction. The horizontal barrier rib has a first horizontal barrier rib provided between the red discharge cells, a second horizontal barrier rib provided between the green discharge cells, and a third horizontal barrier rib provided between the blue discharge cells and having a smaller width than the first and second horizontal barrier ribs.

Description:
[0001]     This application claims the benefit of Korean Patent Application No. P2003-102178 filed in Korea on Dec. 31, 2003, which is hereby incorporated by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates to a plasma display panel, and more particularly to a plasma display panel that is adaptive for improving a color coordinates correction and a color temperature.  
         [0004]     2. Description of the Related Art  
         [0005]     Generally, a plasma display panel (PDP) radiates a phosphorous material using an ultraviolet ray with a wavelength of 147 nm generated upon discharge of an inactive mixture gas such as He+Xe, Ne+Xe or He+Ne+Xe, to thereby display a picture including characters and graphics. Such a PDP is easy to be made into a thin-film and large-dimension type. Moreover, the PDP provides a very improved picture quality owing to a recent technical development. Particularly, since a three-electrode, alternating current (AC) surface-discharge PDP has wall charges accumulated in the surface thereof upon discharge and protects electrodes from a sputtering generated by the discharge, it has advantages of a low-voltage driving and a long life.  
         [0006]     Referring to  FIG. 1 , a discharge cell of the conventional three-electrode, AC surface-discharge PDP includes a scan electrode Y and a sustain electrode Z provided on an upper substrate  10 , and an address electrode X provided on a lower substrate  18 .  
         [0007]     The scan electrode Y includes a first transparent electrode  12 Y, and a first bus electrode  13 Y provided at the rear side of the first transparent electrode  12 Y. The sustain electrode Z includes a second transparent electrode  12 Z, and a second bus electrode  13 Z provided at the rear side of the second transparent electrode  12 Z.  
         [0008]     The first and second transparent electrodes  12 Y and  12 Z are usually made from a transparent material so as to transmit a light from the discharge cell. At the rear sides of the first and second transparent electrodes  12 Y and  12 Z, the first and second bus electrodes  13 Y and  13 Z made from a metal material are provided in parallel to the first and second transparent electrodes  12 Y and  12 Z. The first and second bus electrodes  13 Y and  13 Z are used for applying driving signals to the first and second transparent electrodes  12 Y and  12 Z having a high resistance value. On the upper substrate  10  provided with the first transparent electrode  12 Y and the second transparent electrode  12 Z in parallel to each other, an upper dielectric layer  14  and a protective film  16  are disposed. Wall charges generated upon plasma discharge are accumulated into the upper dielectric layer  14 . The protective film  16  prevents a damage of the upper dielectric layer  14  caused by a sputtering during the plasma discharge and improves the emission efficiency of secondary electrons. This protective film  16  is usually made from magnesium oxide (MgO).  
         [0009]     A lower dielectric layer  22  and barrier ribs  24  are formed on the lower substrate  18  provided with the address electrode X. The surfaces of the lower dielectric layer  22  and the barrier ribs  24  are coated with a phosphorous material layer  26 . The address electrode X is formed in a direction crossing the first transparent electrode  12 Y and the second transparent  12 Z. The barrier rib  24  is provided in parallel to the address electrode X to thereby prevent an ultraviolet ray and a visible light generated by a discharge from being leaked to the adjacent cells.  
         [0010]     The phosphorous material layer  26  is excited by an ultraviolet ray generated during the plasma discharge to generate any one of red, green and blue visible light rays. An inactive mixture gas, such as He+Xe, Ne+Xe or He+Ne+Xe, for providing a gas discharge is injected into a discharge space defined between the upper and lower substrate  10  and  18  and the barrier rib  24 .  
         [0011]     In Such a PDP, the discharge cells sustain a discharge by the surface discharge between the scan electrode Y and the sustain electrode Z after they were selected by the opposite discharge between the scan electrode Y and the sustain electrode Z. The discharge cell of the PDP radiates the phosphorous material  26  by an ultraviolet ray generated upon the sustain discharge, thereby emitting a visible light into the exterior thereof. As a result, the PDP having the discharge cells displays a picture.  
         [0012]     In such a conventional PDP, the phosphorous material  26  is excited by a vacuum ultraviolet ray Δ UV with a short wavelength produced upon discharge to generate a unique color visible light ray, thereby displaying red, green and blue colors R, G and B that are three initial colors of a light at each discharge cell. In the PDP, a color coordinates of a full white is greatly influenced by a substance of the phosphorous material  26  and a used inactive gas. For this reason, the phosphorous material  26  requires a coating over a wider area besides an improvement of its substance property and a uniform coating characteristic at the inner wall of the barrier rib.  
         [0013]     To this end, the barrier rib coated with the phosphorous material  26  needs to have a structurally wide area. In other words, a stripe-type barrier rib  24  as shown in  FIG. 2  has an advantage in that it does not have any structure for making a shut-off between the barrier ribs  24  to form a flowing path of an air, thereby making an air exhaust and a gas injection easily when an exhaust process of making the discharge space into a vacuum state for the sake of an injection of the mixture gas is performed. On the other hand, the PDP adopting the stripe-type barrier rib  24  has disadvantages in that it fails to have a high brightness characteristic because an amount of the visible light amount produced by a radiation of the phosphorous material  26  within the discharge cell is small due to a limitation in its area coated with the phosphorous material and in that a width of the gas flowing path between the upper and lower discharge cells is large due to a non-existence of the structure provided between the barrier ribs  24  at a region where the upper and lower discharge cells are divided, thereby causing a cross talk to lead to a color interference phenomenon between the pixels of the PDP.  
         [0014]     In such a conventional PDP having such a stripe-type barrier rib  24 , in order to achieve a color temperature improvement and a color coordinates correction, a structure of the stripe-type barrier rib  24  is provided in a non-symmetric shape to change a mutual area ratio among the discharge cell for implementing a red color R, the discharge cell for implementing a green color G and, the discharge cell for implementing a blue color B, thereby compensating a color coordinates based on a change in the light-emission area. In this case, the discharge cell for implementing the red color R has a higher light-emission brightness than the discharge cells for implementing the green color G and the blue color B, whereas the discharge cell for implementing the green color G has a higher light-emission brightness than the discharge cell for implementing the blue color B.  
         [0015]     Accordingly, a distance (i.e., pitch) between the barrier ribs  28  for separating the red(R), green(G) and blue(B) discharge cells from each other is formed in a non-symmetric type to make a relationship of the blue(B)&gt;the green(G)&gt;the red(R), thereby adjusting a color coordinates of the full white. Therefore, a pitch of the discharge cell for implementing the blue color B has the largest size, and a pitch of the discharge cell for implementing the green color G has a smaller size than the blue(B) discharge cell and a larger size than the red(R) discharge cell. Thus, a pitch of the blue(B) discharge cell is increased to have a larger light-emission area than the symmetrical structure, thereby providing a color coordinates correction and a color temperature improvement.  
         [0016]     However, the PDP in which a pitch between the discharge cells for implementing the red(R), green(G) and blue(B) colors has a non-symmetric structure has a problem in that horizontal pitches of the red(R), green(G) and blue(B) discharge cells are too reduced as a resolution of the PDP goes higher, thereby causing an increase of discharge voltage, a reduction of operation margin and a reduction of brightness/efficiency characteristics.  
       SUMMARY OF THE INVENTION  
       [0017]     Accordingly, it is an object of the present invention to provide a plasma display panel that is adaptive for improving a color coordinates correction and a color temperature.  
         [0018]     In order to achieve these and other objects of the invention, a plasma display panel according to one embodiment of the present invention includes a vertical barrier rib for separating red, green and blue discharge cells from each other in a longitudinal direction; and a horizontal barrier rib, being provided between the vertical barrier ribs, for separating the red, green and blue discharge cells from each other in a wide direction, wherein said horizontal barrier rib has a first horizontal barrier rib provided between the red discharge cells; a second horizontal barrier rib provided between the green discharge cells; and a third horizontal barrier rib provided between the blue discharge cells and having a smaller width than the first and second horizontal barrier ribs.  
         [0019]     In the plasma display panel, the first horizontal barrier rib has a larger width than the second horizontal barrier rib.  
         [0020]     The vertical barrier rib is provided such that horizontal pitches of the red, green and blue discharge cells are equal to each other.  
         [0021]     Herein, the vertical barrier ribs have the same width. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]     These and other objects of the invention will be apparent from the following detailed description of the embodiments of the present invention with reference to the accompanying drawings, in which:  
         [0023]      FIG. 1  is a perspective view showing a discharge cell structure of a conventional plasma display panel;  
         [0024]      FIG. 2  is a plan view showing a discharge cell having a symmetrical structure shown in  FIG. 1 ;  
         [0025]      FIG. 3  is a plan view showing a discharge cell having a non-symmetrical structure shown in  FIG. 1 ;  
         [0026]      FIG. 4  is a perspective view showing a structure of a plasma display panel according to an embodiment of the present invention; and  
         [0027]      FIG. 5  is a plan view of the plasma display panel shown in  FIG. 4 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0028]     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.  
         [0029]     Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to  FIGS. 4 and 5 .  
         [0030]      FIG. 4  is a perspective view showing a structure of a plasma display panel according to an embodiment of the present invention, and  FIG. 5  is a plan view of a lower substrate in the plasma display panel shown in  FIG. 4 .  
         [0031]     Referring to  FIG. 4  and  FIG. 5 , a discharge cell of the PDP according to the embodiment of the present invention includes a scan electrode Y and a sustain electrode Z provided on an upper substrate  50 , and an address electrode X provided on a lower substrate  68 .  
         [0032]     The scan electrode Y includes a first transparent electrode  52 Y, and a first bus electrode  53 Y provided at the rear side of the first transparent electrode  12 Y. The sustain electrode Z includes a second transparent electrode  52 Z, and a second bus electrode  53 Z provided at the rear side of the second transparent electrode  52 Z.  
         [0033]     The first and second transparent electrodes  52 Y and  52 Z are usually made from a transparent material so as to transmit a light from the discharge cell. At the rear sides of the first and second transparent electrodes  52 Y and  52 Z, the first and second bus electrodes  53 Y and  53 Z made from a metal material are provided in parallel to the first and second transparent electrodes  52 Y and  52 Z. The first and second bus electrodes  53 Y and  53 Z are used for applying driving signals to the first and second transparent electrodes  52 Y and  52 Z having a high resistance value. On the upper substrate  50  provided with the first transparent electrode  52 Y and the second transparent electrode  52 Z in parallel to each other, an upper dielectric layer  54  and a protective film  56  are disposed. Wall charges generated upon plasma discharge are accumulated into the upper dielectric layer  54 . The protective film  56  prevents a damage of the upper dielectric layer  54  caused by a sputtering during the plasma discharge and improves the emission efficiency of secondary electrons. This protective film  56  is usually made from magnesium oxide (MgO).  
         [0034]     A lower dielectric layer  62  and barrier ribs  64  are formed on the lower substrate  68  provided with the address electrode X. The surfaces of the lower dielectric layer  62  and the barrier ribs  64  are coated with a phosphorous material (not shown). The address electrode X is formed in a direction crossing the first transparent electrode  52 Y and the second transparent  52 Z.  
         [0035]     The barrier rib  64  is provided in parallel to the address electrode X to prevent an ultraviolet ray generated by a discharge from being leaked to the adjacent cells, thereby preventing an electrical and optical cross talk between the adjacent discharge cells. To this end, the barrier rib  64  includes a vertical barrier rib  72  provided in parallel to the address electrode X, and a horizontal barrier rib  70  provided between the adjacent vertical barrier ribs  72 .  
         [0036]     The vertical barrier ribs  72  are formed at the same width and the same distance to equalize horizontal pitches W 1 , W 2  and W 3  of red(R), green(G) and blue(B) discharge cells.  
         [0037]     The horizontal barrier rib  70  is provided between the vertical barrier ribs  72  such that the red(R), green(G) and blue(B) discharge cells have a different width from each other. The horizontal barrier rib  70  includes a first horizontal barrier rib  70   a  provided between the red discharge cells and having a first width, a second horizontal barrier rib  70   b  provided between the green discharge cells and having a second width, and a third horizontal barrier rib  70   c  provided with the blue discharge cells and having a third width. Thus, the blue discharge cell B has the largest light-emission area; the green discharge cell G has the next light-emission area; and the red discharge cell R has the smallest light-emission area. Accordingly, the blue discharge cell B has the largest coated area of the phosphorous material as well as the widest discharge space, thereby increasing a light-emission brightness of the blue discharge cell B. As a result, a light-emission brightness of the discharge cell for implementing the red color R is higher than that of the discharge cells for implementing the green color G and the blue color B while a light-emission brightness of the discharge cell for implementing the green color G is higher than that of the discharge cell for implementing the blue color B, so that the entire light-emission brightness becomes uniform.  
         [0038]     The phosphorous material is coated onto the surfaces of the lower dielectric layer  62  and the barrier rib  64  to generate any one of red, green and blue visible light rays. An inactive mixture gas, such as He+Xe, Ne+Xe or He+Ne+Xe, for providing a gas discharge is injected into a discharge space defined between the upper and lower substrate  50  and  58  and the barrier rib  64 .  
         [0039]     In such a PDP, the discharge cells sustain a discharge by the surface discharge between the scan electrode Y and the sustain electrode Z after they were selected by the opposite discharge between the scan electrode Y and the sustain electrode Z. The discharge cell of the PDP radiates the phosphorous material by an ultraviolet ray generated upon the sustain discharge, thereby emitting a visible light into the exterior thereof. As a result, the PDP having the discharge cells displays a picture.  
         [0040]     Such a phosphorous material in the PDP according to the embodiment of the present invention is excited by a vacuum ultraviolet ray with a short wavelength produced upon discharge to generate a unique color visible light ray, thereby displaying red, green and blue colors R, G and B that are three initial colors of a light at each discharge cell. In this case, since the vacuum ultraviolet ray is mainly generated at the center portion of the discharge cell, it is more increased as it becomes closer to the center portion of the discharge cell, thereby raising a conversion efficiency of the visible light.  
         [0041]     Accordingly, in the PDP according to the embodiment of the present invention, widths of horizontal barrier ribs  124  adjacent to the red(R), green(G) and blue(B) discharge cells are differentiated to differently define the discharge spaces of the red(R), green(G) and blue(B) discharge cells, thereby improving a color temperature as well as correcting a color coordinates. In other words, the discharge space of the green(G) discharge cell can be enlarged to more improve a light-emission brightness of the green(G) discharge cell in comparison to the prior art. Moreover, the discharge space of the blue(B) discharge cell is larger than that of other discharge cells, so that it becomes possible to more improve a light-emission brightness of the blue(B) discharge cell in comparison to the prior art. As a result, the PDP according to the embodiment of the present invention can improve a color temperature and correct a color coordinates while making no effect to a driving voltage and brightness/efficiency characteristics at a high-definition panel.  
         [0042]     As described above, the plasma display panel according to the present invention includes a different width of barrier ribs for each red, green and blue discharge cell. Accordingly, it becomes possible to improve a color temperature as well as to correct a color coordinates while making no affect to a driving voltage and brightness/efficiency characteristics at a high-definition panel.  
         [0043]     Although the present invention has been explained by the embodiments shown in the drawings described above, it should be understood to the ordinary skilled person in the art that the invention is not limited to the embodiments, but rather that various changes or modifications thereof are possible without departing from the spirit of the invention. Accordingly, the scope of the invention shall be determined only by the appended claims and their equivalents.