Patent Publication Number: US-2003227427-A1

Title: Plasma display panel

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The present invention relates to a PDP (plasma display panel), and in particular to a PDP capable of preventing distortion of images and obtaining high brightness and high efficiency.  
       [0003] 2. Description of the Prior Art  
       [0004] Recently, as a next generation digital multimedia display device, various FPDs (flat panel display) have been developed. There are a LCD (liquid crystal display), a FED (field emission display), a PDP (plasma display panel) and an EL (electroluminescence), etc. In particular, because the PDP has many advantages in comparison with other FPDs, it has attracted public attention.  
       [0005] Unlike other FPDs, the PDP is a self-emission display using plasma gas discharge, has a picture quality as good as that of a CRT (cathode ray tube) and can be easily fabricated as a large screen. In more detail, the PDP is mostly expected as a large screen display device having a high picture quality and a large screen. In addition, a three electrode AC surface discharge type PDP is typical, and it is driven by AC voltage.  
       [0006] Hereinafter, a discharge cell of the PDP will be described with reference to accompanying FIG. 1. Herein, a cell for emitting one visible light of R (red), G (green) and B (blue) is called a discharge cell, and a cell consisting of one pixel by including three discharge cells is called a pixel cell.  
       [0007]FIG. 1 is a sectional view illustrating the discharge cell of the PDP in accordance with the conventional art.  
       [0008] As depicted in FIG. 1, by combining a front plate  110  with a back plate  120  and injecting a discharge gas, the discharge cell of the PDP is formed.  
       [0009] The front plate  110  includes an upper glass plate  100 ; a scan electrode  102 Y and a sustain electrode  102 Z formed on the upper glass substrate  100 ; an upper dielectric layer  103  formed on the upper glass substrate  100  and the electrodes  102 Y,  102 Z in order to store wall charge generated in plasma discharge; and a protection layer  105  formed on the upper dielectric layer  103  in order to prevent the upper dielectric layer  103  from being damaged by ion sputtering occurred in plasma discharge and lower an operating voltage and a sustain voltage of discharge plasma by improving a discharge efficiency of secondary electron.  
       [0010] Herein, the scan electrode  102 Y includes a first transparent electrode  102 Y 1  and a first bus electrode  102 Y 2 , and the sustain electrode  102 Z includes a second transparent electrode  102 Z 1  and a second bus electrode  102 Z 2 . In addition, MgO is generally used for the protection layer  105 .  
       [0011] The back plate  120  includes a lower glass plate  101 ; an address electrode  102 X formed on the lower glass substrate  101 ; a lower dielectric layer  104  coated on the address electrode  102 Z; a barrier rib  107  vertically formed on the lower dielectric layer  104  in order to form a discharge space in the discharge cell and prevent cross-talk due to ultraviolet rays and visible rays generated in the discharge space; and a phosphor  106  coated on the surface of the lower dielectric layer  104  and the barrier rib  107  in order to emit one visible light of three primary colors (R, G, B) by being excited by the ultraviolet rays generated in plasma discharge.  
       [0012] In the PDP, the discharge cell arranged as a matrix shape is accessed by using the address electrode  102 X and the scan electrode  102 Y of the discharge cell, and the accessed discharge cell sustains discharge by surface-discharge between the scan electrode  102 Y and the sustain electrode  102 Z. Accordingly, in the PDP, the phosphor  106  is excited by ultraviolet rays generated in the sustain discharge, visible rays are discharged from the phosphor  106  to the outside of the cell, and accordingly an image is displayed through the discharge cell arranged as the matrix format. Hereinafter, the barrier rib structure of the PDP in accordance with the conventional art will be described with reference to accompanying FIGS.  2 ˜ 6 .  
       [0013]FIG. 2 shows a stripe type barrier rib of a PDP in accordance with the conventional art, and FIG. 3 shows a wall type barrier rib of a PDP in accordance with the conventional art.  
       [0014] As depicted in FIG. 2, in a stripe type barrier rib  207 , discharge gas can be easily discharge, however, because a coating area of the phosphor is small, brightness may be lowered.  
       [0015] As depicted in FIG. 3, in a wall type barrier rib  307 , because a coating area of the phosphor is large, brightness can be improved, however, discharge gas can not be easily discharged.  
       [0016] As described above, in order to solve problems of the stripe type and the wall type barrier rib structures of the PDP, a delta type barrier rib structure has been presented.  
       [0017]FIG. 4 is a plan view illustrating the delta type barrier rib of a PDP in accordance with the conventional art.  
       [0018] As depicted in FIG. 4, the delta type barrier rib structure includes a barrier rib  407 A surrounding the discharge cell as a hexahedral shape; and a barrier rib  407 B for connecting a discharge space formed by the barrier rib  407 A to a channel  408  having small width.  
       [0019] In the PDP having the delta type barrier rib, because the discharge cell is surrounded as the hexahedral shape by the barrier rib, phosphor coating area and barrier rib refractivity are increased, and accordingly brightness can be improved. And, because each discharge cell is connected to the channel  408 , discharge and injection of discharge gas can be smoothly performed. In addition, in the delta type barrier rib  407 , because a discharge starting voltage of the channel  408  is higher than a discharge starting voltage of the discharge space, it is possible to decrease confusion in barrier rib direction. Herein, contact potential not less than a certain voltage is required for starting discharge between the scan and sustain electrodes, and a voltage as a border is called the discharge starting voltage.  
       [0020] However, in the PDP having the delta type barrier rib structure, because the scan and sustain electrodes  402 Y,  402 Z have to be arranged symmetrically in all discharge cells, unlike other barrier rib structures, the bus electrode  402 Y 2  is arranged at the center of the transparent electrode  402 Y 1 . Accordingly, visible rays discharged from each discharge cell is shielded by the bus electrode  402 Y 2 , and brightness is decreased as much as the shielded visible rays.  
       [0021]FIG. 5 is a plan view illustrating scan and sustain electrodes of a PDP having a quadrangular-delta type barrier rib structure in accordance with the conventional art, and FIG. 6 is a plan view illustrating an address electrode of the PDP having the quadrangular-delta type barrier rib structure in accordance with the conventional art.  
       [0022] As depicted in FIG. 5, the PDP having the quadrangular-delta type barrier rib structure includes a scan electrode  502 Y having a first bus electrode  502 Y 2 , and a first transparent electrode  502 Y 1  extended from the first bus electrode  502 Y 2 ; a sustain electrode  502 Z having a second bus electrode  502 Z 2  and a second transparent electrode  502 Z 1  extended from the second bus electrode  502 Z 2 ; and a quadrangular-delta type barrier rib  507  having a first barrier rib  507 A formed side by side with the first bus electrode  502 Y 2  and a second barrier rib  507 B formed in the cross direction of the first barrier rib  507 A so as to be connected with the first barrier rib  507 A.  
       [0023] As depicted in FIG. 6, the PDP address electrode  602 X having the quadrangular-delta type barrier rib structure  607  includes an address electrode  602 X 1  widely formed so as to be corresponded to the discharge space formed by the quadrangular-delta type barrier rib  607 ; and an address electrode  602 X 2  having a narrow width so as to be connected with the widely formed address electrode  602 X 1 .  
       [0024] As described above, in the PDP having the quadrangular-delta type barrier rib structure, because the discharge cell is surrounded as a quadrangular shape by the quadrangular-delta type barrier rib  607 , a phosphor coating area is increased, barrier rib refractivity is increased, and accordingly brightness can be improved.  
       [0025] However, in the PDP having the quadrangular-delta type barrier rib structure, because each discharge cell is formed as not a matrix shape but a zigzag shape, it is difficult to describe a straight line. Accordingly, images of the PDP may be distorted. In addition, because a size of each cell is regular, it may be difficult to adjust a color temperature.  
       [0026] As described above, in the PDP having the quadrangular-delta type barrier rib structure, because the discharge cell has the quadrangular shape, it has discharge efficiency lower than that of a square shape. In addition, in the delta shape and the quadrangular-delta type barrier rib structures, because discharge cells have the same size, it is difficult to adjust a color temperature and brightness, because discharge cells are formed as a zigzag shape, when a straight line is described on the PDP, picture quality lowering phenomenon may occur. The PDP in accordance with the conventional art has fundamental problems related to distortion, brightness and efficiency lowering.  
       SUMMARY OF THE INVENTION  
       [0027] In order to solve the above-mentioned problems, it is an object of the present invention to provide a PDP capable of preventing distortion of images of a PDP by forming differently structures of discharge cells respectively formed in pixel cells.  
       [0028] It is another object of the present invention to provide a PDP capable of improving brightness of a PDP by forming differently structures of discharge cells formed in pixel cells.  
       [0029] It is yet another object of the present invention to provide a PDP capable of improving efficiency of a PDP by forming differently structures of discharge cells formed in pixel cells.  
       [0030] In order to achieve the above-mentioned objects, a PDP (plasma display panel) in accordance with the present invention includes plural pixel cells respectively having differently structured three discharge cells.  
       [0031] In order to achieve the above-mentioned objects, in a PDP including plural pixel cells respectively having differently structured three discharge cells, a PDP includes a first and a second discharge cells formed so as to be corresponded with each other; and a third discharge cell formed so as to have a horizontal length same with a length from the first discharge cell to the second discharge cell and have a vertical length shorter than that of the first and second discharge cells.  
       [0032] Other objects and characteristics will be described clearly with reference to accompanying drawings. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0033] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.  
     [0034] In the drawings:  
     [0035]FIG. 1 is a sectional view illustrating a structure of a discharge cell of a PDP in accordance with the conventional art;  
     [0036]FIG. 2 shows a stripe type barrier rib of the PDP in accordance with the conventional art;  
     [0037]FIG. 3 shows a wall type barrier rib of the PDP in accordance with the conventional art;  
     [0038]FIG. 4 is a plan view illustrating a delta type barrier rib of the PDP in accordance with the conventional art;  
     [0039]FIG. 5 is a plan view illustrating scan and sustain electrodes of a PDP having a quadrangular-delta type barrier rib structure in accordance with the conventional art;  
     [0040]FIG. 6 is a plan view illustrating an address electrode of the PDP having the quadrangular-delta type barrier rib structure in accordance with the conventional art.  
     [0041]FIG. 7 is a plan view illustrating a barrier rib structure of a PDP in accordance with the present invention;  
     [0042]FIG. 8 is a plan view illustrating an electrode structure of a PDP in accordance with the present invention; and  
     [0043]FIGS. 9A and 9B are sectional views illustrating a structure of a discharge cell of a PDP in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
     [0044] Hereinafter, the preferred embodiments of a PDP capable of preventing distortion, improving brightness and bettering efficiency by differently forming structures of discharge cells formed in pixel cells will be described with reference to accompanying FIGS.  7 ˜ 9 B.  
     [0045]FIG. 7 is a plan view illustrating a barrier rib structure of a PDP in accordance with the present invention.  
     [0046] As depicted in FIG. 7, in the PDP having plural pixel cells respectively having a discharge cell having a structure different from each other, the pixel cell  709  includes a first and a second discharge cells S 1 , S 2  formed so as to be corresponded with each other as left/right; a third discharge cell S 3  formed below the two discharge cells S 1 , S 2  so as to have a longer horizontal length and a shorter vertical length than those of the two discharge cells; and a quadrangular barrier rib  707  formed so as to surround the first, second and third discharge cells S 1 , S 2 , S 3  in order to prevent cross-talk with adjacent discharge cells and form a discharge space. Herein, it is preferable to form the pixel cell  709  as a square shape in order to improve discharge efficiency.  
     [0047] Because the first, second and third discharge cells S 1 , S 2 , S 3  have different shapes, an electrode arranged in each discharge cell is differently formed.  
     [0048]FIG. 8 is a plan view illustrating an electrode structure of a PDP in accordance with the present invention.  
     [0049] As depicted in FIG. 8, in the PDP having plural pixel cells respectively having differently shaped-discharge cells, the first and second discharge cell respectively include a bus electrode  802 Y 2 ,  802 Z 2 ; a transparent electrode  802 Y 1 ,  802 Z 1  extended from the bus electrode  802 Y 2 ,  802 Z 2  so as to be corresponded to it; and an address electrode  802 X crossed the bus electrode  802 Y 2 ,  802 Z 2  and overlapped with the transparent electrode  802 Y 1 ,  802 Z 1 . On the other hand, the third discharge cell S 3  includes bus electrodes  802 Z 2 ,  812 Y 2 ; a transparent electrode  812 Y 1 ,  812 Z 1  extended from the bus electrode  802 Z 2 ,  812 Y 2  so as to be corresponded to it; and an address electrode  802 X crossed the bus electrode  802 Z 2 ,  812 Y 2  and overlapped with the transparent electrode  812 Y 1 ,  812 Z 1 . Herein, the transparent electrodes  812 Y 1 ,  812 Z 1  of the third discharge cell have a longer horizontal length and a shorter vertical length than those of the transparent electrodes  802 Y 1 ,  802 Z 1  formed on the first and second discharge cells S 1 , S 2 .  
     [0050] As described above, in one pixel cell, because the third discharge cell S 3  has a size different from that of the first and second discharge cells S 1 , S 2 , a size of the transparent electrodes  812 Y 1 ,  812 Z 1  formed in each discharge cell is different from that of the transparent electrodes  802 Y 1 ,  802 Z 1 . Herein, the address electrode  802 X is jointly owned by the discharge cells adjacent up and down. However, in the third discharge cell S 3 , a horizontal length of the transparent electrodes  812 Y 1 ,  812 Z 1  is limited so as to prevent miss discharge occurrence between the address electrode  802 X passing the first and third discharge cells S 1 , S 3  and the second/third discharge cells S 2 , S 3 . Accordingly, the address electrode  802 X has to be patterned appropriately in order to prevent the miss discharge occurrence.  
     [0051] The transparent electrode  802 Y 1 ,  802 Z 1 ,  812 Y 1 ,  812 Z 1  is made of a transparent conductive material having light transmittivity not less than 90%, for example, indium tin oxide, etc. However, because the transparent electrode  802 Y 1 ,  802 Z 1 ,  812 Y 1 ,  812 Z 1  has low conductivity, the bus electrode  802 Y 2 ,  802 Z 2 ,  812 Y 2  is made of a metal material having high electric conductivity in order to compensate resistance element. Accordingly, preferably bus electrode  802 Y 2 ,  802 Z 2 ,  812 Y 2  has a small width and is made of a metal material having high electric conductivity such as Ag or Cu.  
     [0052]FIGS. 9A and 9B are sectional views illustrating a structure of a discharge cell of a PDP in accordance with the present invention.  
     [0053]FIG. 9A is a sectional view illustrating the first and second discharge cells of the PDP in accordance with the present invention; and FIG. 9B is a sectional view illustrating the third discharge cell of the PDP in accordance with the present invention.  
     [0054] As depicted in FIG. 9A, a front plate  910  of the first and second discharge cells S 1 , S 2  includes an upper glass substrate  900 ; a scan electrode  902 Y and a sustain electrode (not shown) formed on the top surface of the upper glass substrate  900 ; an upper dielectric layer  903  formed on the upper glass substrate  900 , the scan electrode  902 Y and the sustain electrode in order to store wall charge generated in plasma discharge; and a protection layer  905  formed on the upper dielectric layer  903  in order to increase life-span of the PDP by preventing damage of the upper dielectric layer  903  from ion sputtering occurred in plasma discharge and lower a driving voltage and a sustain voltage of discharge plasma by improving a discharge efficiency of secondary electron.  
     [0055] Herein, the scan electrode  902 Y and the sustain electrode (not shown) include a bus electrode  902 Y 2  having a horizontally long length; and a transparent electrode  902 Y 1  extended from the bus electrode  902 Y 2  and having a horizontal length shorter than that of the bus electrode  902 Y 2 .  
     [0056] A back plate  920  of the first and second discharge cells S 1 , S 2  includes a lower glass substrate  901 ; an address electrode  902 X formed on the lower glass substrate  901 ; a lower dielectric layer  904  coated on the lower glass substrate  901  having the address electrode  902 X; a barrier rib  907  formed on the lower dielectric layer  904  in order to form a discharge space and prevent cross-talk due to ultraviolet and visible rays generated in the discharge space; and a phosphor  906  coated on the surface of the lower dielectric layer  904  and the barrier rib  907  in order to emit one visible ray of three primary colors as R, G, B by being excited by the ultra violet light generated in plasma discharge. Herein, the address electrode  902 X 1  of the first discharge cell S 1  is formed toward left of the discharge space so as to be corresponded to the transparent electrode  902 Y 1 , and the address electrode  902 X 3  of the second discharge cell S 2  is formed toward right of the discharge space so as to be corresponded to the transparent electrode  902 Y 1 . In addition, the other address electrode  902 X 2  is formed side by side with the barrier rib  907  so as not to occur miss discharge with the transparent electrode  902 Y 1 .  
     [0057] And, by combining the front and back plates  910 ,  920  and injecting a discharge gas, the first and second discharge cells S 1 , S 2  of the PDP in accordance with the present invention is formed.  
     [0058] As depicted in FIG. 9B, a front plate of the third discharge cell S 3  includes an upper glass substrate  900 ; a scan electrode  912 Y and a sustain electrode (not shown) formed on the upper glass substrate  900 ; an upper dielectric layer  903  formed on the scan electrode  912 Y and the sustain electrode in order to store electric charge in plasma discharge; and a protection layer  905  formed on the upper dielectric layer  903  in order to increase life-span of the PDP by preventing damage of the upper dielectric layer  903  from ion sputtering occurred in plasma discharge and lower a driving voltage and a sustain voltage of discharge plasma by improving a discharge efficiency of secondary electron.  
     [0059] Herein, the scan electrode  902 Y and the sustain electrode (not shown) include a bus electrode  912 Y 2  having a horizontally long length; and a transparent electrode  912 Y 1  extended from the bus electrode  912 Y 2  and having a horizontal length shorter than that of the transparent electrode  902 Y 1  of the first and second discharge cells S 1 , S 2 .  
     [0060] A back plate of the third discharge cell S 3  includes a lower glass substrate  901 ; an address electrode  902 X formed on the lower glass substrate  901 ; a lower dielectric layer  904  coated on the lower glass substrate  901  having the address electrode  902 X; a barrier rib  907  formed on the lower dielectric layer  904  in order to form a discharge space and prevent cross-talk due to ultraviolet and visible rays generated in the discharge space; and a phosphor  906  coated on the surface of the lower dielectric layer  904  and the barrier rib  907  in order to emit one visible ray of three primary colors as R, G, B by being excited by the ultra violet light generated in plasma discharge.  
     [0061] Herein, in the third discharge cell, there are three address electrodes  902 X on the lower glass substrate  901 . One address electrode  902 X 2  is corresponded to the center of the transparent electrode  912 Y 1 , and the rest two address electrodes  902 X 1 ,  902 X 3  are respectively formed in spaces corresponded to between the transparent electrode  912 Y 1  and the barrier rib  907  so as not to be corresponded to the transparent electrode  912 Y 1 . Herein, the two address electrodes  902 X 1 ,  902 X 3  respectively co-owned between the first and third discharge cells S 1 , S 3  and between the second and third discharge cells S 2 , S 3 .  
     [0062] And, by combining the front and back plates  910 ,  920  and injecting a discharge gas, the third discharge cell S 3  of the PDP in accordance with the present invention is formed.  
     [0063] As described above, in the PDP including plural pixel cells respectively having differently structured discharge cells in accordance with the present invention, it is possible to have a structure capable of combining-obtaining advantageous of PDPs in accordance with the conventional art. In more detail, it is possible to solve problems related to distortion, brightness and efficiency lowering occurred in the conventional art.  
     [0064] In the PDP including plural pixel cells respectively having differently structured discharge cells in accordance with the present invention, unlike the conventional art, among three discharge cells consisting of one pixel cell, one discharge cell has a longer horizontal length and a shorter vertical length in comparison with the rest two discharge cells. Accordingly, unlike the delta and the quadrangular-delta type barrier rib structures having the same discharge cell size, in the present invention, discharge cells have different sizes, and accordingly it is possible to adjust a color temperature and improve brightness.  
     [0065] In the PDP including plural pixel cells respectively having differently structured discharge cells in accordance with the present invention, unlike the delta and the quadrangular-delta type barrier rib structures having the zigzag shape, because pixel cells are arranged as a certain matrix shape, in describing of a straight line on the PDP, distortion phenomenon can be prevented.  
     [0066] In addition, in the PDP including plural pixel cells respectively having differently structured discharge cells in accordance with the present invention, a shape of each cell is similar to a square shape in comparison with a discharge cell of a stripe type barrier rib structure, and accordingly discharge efficiency can be improved.  
     [0067] In addition, a barrier rib fabrication method and a driving method are the same with those of the stripe type and wall type structure, and accordingly it is possible improve brightness and efficiency without additional processes.  
     [0068] As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.