Abstract:
A plasma display panel with uniform discharge characteristics. The plasma display panel comprises a buffer layer located between display regions and exhaust holes to force impurities produced during an exhausting process to accumulate between the buffer layer and sealing layer, and be successively adsorbed by a getter layer. As a result, unusual discharge characteristics and nonuniform definitions induced by impurities can be prevented.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a plasma display panel, and more particularly to a plasma display panel with uniform discharge characteristics.  
         [0003]     2. Description of the Related Art  
         [0004]     Flat panel displays (FPD), such as liquid crystal displays (LCD), organic light emitting diodes (OLED) and plasma display panels (PDP), are rapidly replacing cathode ray tubes (CRT). Plasma display panels are self-emitting, highly luminous, provide wider viewing angle, and have a simpler fabrication process. Thus they are a popular choice for industry.  
         [0005]     A PDP is a display device employing charges accumulated by electrode discharge. Due to a variety of advantages, such as large scale, high capacity and full-color capability, the PDP has become one of the most popular flat panel displays for various applications.  
         [0006]      FIG. 1  is a cross section of a conventional plasma display panel. A conventional PDP  10  comprises a front glass substrate  12  and a rear substrate  14 , parallel and opposite each other. The front glass substrate  12  has a plurality of parallel transverse electrodes  20 , and a protective layer  26  is further formed covering these transverse electrodes  20 .  
         [0007]     The rear glass substrate  14  has a plurality of barrier ribs  28  arranged in parallel and spaced apart dividing the gap between the substrates  12  and  14  into a plurality of groups of discharge spaces  16 . Each group of the discharge spaces  16  includes a red discharge space, a green discharge space, and a blue discharge space.  
         [0008]     Additionally, the rear glass substrate  14  has a plurality of parallel longitudinal electrodes  22  positioned in parallel and between two adjacent barrier ribs  28  to serve as address electrodes, and a dielectric layer  24  is further formed to cover these lengthwise electrodes  22 . Moreover, a fluorescent layer  29  is coated on the rear glass substrate  14  and the sidewalls of the barrier ribs  28  within the discharge space  16 . Two adjacent barrier ribs  28 , the transverse electrode  20 , the longitudinal electrode  22 , the discharge space  16 , and the fluorescent layer  29  comprise a discharge cell  30 .  
         [0009]      FIG. 2  is a top view of the conventional PDP  10 . All discharge cells  30  of the PDP  10  comprise a display region  32 , and a sealing layer  40  is formed outside the display region  32  bonding the peripheries of the substrates  12  and  14 . Furthermore, the PDP  10  comprises an exhaust vent  50  formed in the rear glass substrate  14  and an exhaust pipe  60  connected the exhaust vent  50 , for exhausting gas from and introducing discharge gas, such as Ar or Xe, into the discharge spaces  16 .  
         [0010]     In the conventional PDP structure, impurities result from formation of each element of the discharge cell  30 .  
         [0011]     Accordingly, after assembly of the PDP  10 , gases and impurities reexhausted from the discharge spaces  16  in the PDP  10 . During the exhaust process, however, impurities introduced in the discharge cells  30  near the exhaust vent  50 . The remaining impurities degrade a discharge characteristic of the discharge cells  30  near the exhaust vent  50 , to inhibiting performance thereof, due to resulting nonuniform discharge characteristics and definitions.  
         [0012]     Therefore, it is necessary to efficiently remove impurities remaining in the PDP for preventing degradation of characteristics of the PDP from degradation.  
       SUMMARY OF THE INVENTION  
       [0013]     Accordingly, an object of the present invention is to provide a plasma display panel having a buffer layer located between a display region and an exhaust vent to forcing impurities in the PDP to accumulate between the buffer layer and a sealing layer, and be successively absorbed by a getter layer. As a result, nonuniform discharge characteristics and definitions induced by impurities can be prevented.  
         [0014]     To achieve the above objects, according to the present invention, a plasma display panel comprises parallel first and second substrates apart separated by a predetermined distance. A sealing layer is formed between the first and second substrate for bonding peripheral regions of the first and second substrates. A display region for emitting light is located in a center region of the first and second substrates. An exhaust vent is formed in the second substrate outside the display region. A buffer layer is formed on the second substrate between the exhaust vent and the display region, and a getter layer is formed on the first substrate outside the display region.  
         [0015]     According to the present invention, the second substrate comprises a first region between the sealing layer and the buffer layer, and the getter layer can be partially or fully formed on a second region, corresponding to the first region, of the first substrate. Moreover, the getter layer can be formed on the first substrate adjacent to the second region.  
         [0016]     The present invention also provides another plasma display panel, comprising parallel first and second substrates apart separated by a predetermined distance. A sealing layer is formed between the first and second substrate for bonding peripheral regions of the first and second substrates. A display region for emitting light is located in a center region of the first and second substrates. An exhaust vent is formed in the second substrate outside the display region.  
         [0017]     A buffer layer is formed on the second substrate between the exhaust vent and the display region, wherein the second substrate comprises a first region between the sealing layer and the buffer layer, and the first substrate comprises a second region corresponding to the first region. An active protective layer is formed on the display region of the first substrate extending to the second region.  
         [0018]     According to the present invention, the active protective layer can be formed on the display region of the first substrate extending in the second region. The plasma display panel can further comprise a getter layer formed partially or completely on the second region, wherein the getter layer can be adjacent to the active protective layer.  
         [0019]     A detailed description is given in the following embodiments with reference to the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     The present invention can be more fully understood by reading the subsequent detailed description in conjunction with the examples and references made to the accompanying drawings, wherein:  
         [0021]      FIG. 1  is a cross section of a conventional PDP after a sealing process.  
         [0022]      FIG. 2  is a perspective view of a conventional PDP after a sealing process.  
         [0023]      FIG. 3  is a cross section of a conventional PDP after a gas exhausting-injecting process.  
         [0024]      FIG. 4  is a perspective view of the PDP according to the present invention.  
         [0025]      FIG. 5  is a cross section of the PDP according to the present invention illustrating the positions of the buffer layer and the getter layer.  
         [0026]     FIGS.  6  to  10   b  are partial perspective views of the PDPs according to the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0027]     According to the present invention, the plasma display panel has a buffer layer located between a display region and an exhaust vent to forcing impurities in the PDP to accumulate between the buffer layer and a sealing layer, and successively absorbed by a getter layer. Therefore, the discharge characteristics of the PDP according to the present invention can be improved due to the increased purity of the discharge gas.  
         [0028]     While a PDP is used to illustrate the invention, numerous modifications and variations will be apparent to those skilled in the art.  
         [0029]      FIG. 4  is a perspective view of a PDP according to the present invention. The PDP  100  comprises a first substrate  102  and a second substrate  104  parallel to each other and separated by a predetermined distance. A display region  132  having a plurality of display cells is formed between the first substrate  102  and the second substrate  104 . A sealing layer  140  is formed between the first substrate  102  and the second substrate  104  for bonding peripheral regions thereof respectively, and at least one exhaust vent  150  is formed penetrating the second substrate  104  outside the display region  132 . Furthermore, referring to  FIG. 5 , the display cell  130  according to the present invention comprises a first electrode  120  formed on the first substrate  102 , a protective layer  126  formed on the first electrode  120 , a second electrode  122  formed on the second substrate  104  between two adjacent barrier ribs  128 , a dielectric layer  124  formed over the second substrate  104  covering the second electrode  122 , a phosphor layer  129  coated on the dielectric layer  124  and the barrier rib  128 , and a discharge space  144 .  
         [0030]      FIG. 6  is a partial perspective view of  FIG. 4  further illustrating the PDP  100  according to the present invention. Specifically, the PDP  100  further comprises a buffer layer  160  formed on the second substrate  104  between the exhaust vent  150  and the display region  132 , and a getter layer  162  formed on the first substrate  102  between the sealing layer  140  and the display region  132 . The remaining impurities after exhausting gases from and injecting discharge-gases into the PDP  100  are forced to accumulate in the buffer layer  160 . Suitable material for the buffer layer  160  can be the same as the sealing layer  140 , such as an adhesive or a glass frit. Moreover, the getter layer  162  absorbs impurities accumulated in the buffer layer  160 . Suitable material for the getter layer  162  can be a compound comprising magnesium, aluminum, or zirconium. Preferably, the getter layer and the protective layer  126  are the same material, such as magnesium oxide (MgO).  
         [0031]     As shown in  FIGS. 5 and 6 , the second substrate  104  comprises a first region  164  between the buffer layer  160  and the sealing layer  140 . Additionally, the first substrate  102  comprises a second region  166  corresponding to the first region  164 . In the present invention, the getter layer  162  can be formed partially in the second region  166  as shown in  FIG. 6 . In another aspect, the getter layer  162  can be formed entirely in the second region  166  as shown in  FIG. 7   a.  In yet another aspect, the getter layer  162  can be formed adjacent to the second region  166  as shown in  FIG. 7   b.    
         [0032]     According to the present invention, the buffer layer  160  can be bar-shaped as shown in  FIGS. 7   a  and  7   b,  or other shapes. For example, as shown in  FIGS. 8   a  to  8   e,  the buffer layer  160  can be L-shaped or ladder-shaped. The getter layer  162  can be divided into several regions with the same or different dimensions as shown in  FIGS. 8   d  and  8   e.  Moreover, the getter layer  162  can be cover a region, corresponding to the exhaust vent  150 , of the first substrate  102 .  
         [0033]     In the present invention, since the getter layer  162  and the protective layer  126  can be the same material, such as MgO, an active protective layer  132  can be deposited on the first substrate  102 , substituting for the getter layer  162  and the protective layer  126  in one step, as shown in  FIGS. 9   a  to  9   c.  Specifically, the active protective layer  132  is formed on the original position of the protective layer  126  and extends to the second region  166 . In the present invention, the active protective layer  132  can cover the second region  166  as shown in  FIGS. 9   a  and  9   c.  Moreover, the active protective layer  132  can be adjacent to the second region  166  as shown in  FIG. 9   b.  Referring to  FIGS. 10   a  and  10   b,  the PDP  100  comprising the active protective layer  132  can further comprise a getter layer,  162  formed partially or completely on the second region  166 .  
         [0034]     Accordingly, the PDP of the present invention comprising a buffer layer and a getter layer can effectively remove impurities from discharge spaces, such that, compared with conventional PDPs, unusual discharge characteristics and nonuniform definitions induced by impurities can be prevented. In addition, since the getter layer can be the same material as the protective layer and formed in the same step, the performance of the PDP according to the present invention can be improved without increasing process complexity or cost.  
         [0035]     While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.