Abstract:
A display panel with an improved electrode structure including a cross region in which a plurality of first electrodes and a plurality of second electrodes are arranged to cross each other. A display cell is formed at each cross region. The display panel has an electrode structure in which a first electrode protrusion is formed in the direction of the arrangement of the second electrode and adjacent first electrode protrusions have different arrangements at adjacent cross regions.

Description:
This application claims the benefit of Korean Patent Application No. 2003-58504, filed on Aug. 23, 2003, which is hereby incorporated by reference for all purposes as if fully set forth herein. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a display panel, and more particularly to a display panel with an electrode structure that enhances stable addressing. 
     2. Discussion of the Related Art 
     A typical display panel includes a panel unit and a drive unit. 
       FIG. 1  shows a typical structure for a 3-electrode surface discharging type plasma display panel (PDP).  FIG. 2  shows how a single cell of the panel of  FIG. 1  operates. 
     Referring to  FIG. 1  and  FIG. 2 , address electrode lines (A 1 , A 2 , . . . , Am), dielectric layers  102  and  110 , Y electrode lines (Y 1 , . . . , Yn), X electrode lines (X 1 , . . . , Xn), fluorescent layers  112 , barrier walls  114  (not shown in  FIG. 2 ), and a protective layer  104  are located between the front and rear glass substrates  100  and  106  of a typical surface discharging PDP  1 . 
     The address electrode lines (A 1 , A 2 , . . . , Am) are formed on top of the rear glass substrate  106  in a regular pattern. A dielectric layer  110  is coated on top of the address electrode lines (A 1 , A 2 , . . . , Am). The barrier walls  114  are formed on top of the dielectric layer  110  in parallel with the address electrode lines (A 1 , A 2 , . . . , Am). These barrier walls  114  partition the discharge spaces of each display cell and prevent optical interference between display cells. The fluorescent layers  112  are formed between the barrier walls  114 . 
     The X electrode lines (X 1 , . . . , Xn) and the Y electrode lines (Y 1 , . . . , Yn) are formed under the front glass substrate  100  in a regular pattern, orthogonal to the address electrode lines (A 1 , A 2 , . . . , Am), where each intersection corresponds to a display cell. Each X electrode line (X 1 , . . . , Xn) and Y electrode line (Y 1 , . . . , Yn) can be formed by combining transparent electrode lines (Xna, Yna) made of a transparent conductive material such as Indium Tin Oxide (ITO) with metal electrode lines (Xnb, Ynb), which enhance conductivity. The dielectric layer  102  covers the X electrode lines (X 1 , . . . , Xn) and Y electrode lines (Y 1 , . . . , Yn). A protective layer  104 , which may be made of Mgo and protects the panel  1  from a strong electric field, covers the dielectric layer  102 . A plasma producing gas is injected into the discharge cells  108  before the PDP is sealed. 
     The typical driving method for a PDP as described above allows initialization, address, and display sustaining stages to be sequentially performed in a unit sub-field. The electric charges of the display cells that are to be driven are uniform during the initialization stage. Electric charges for selected and non-selected display cells are determined during the address stage. Display discharge is performed in display cells during the display sustaining stage. During a cell discharge, plasma is formed from the display cell&#39;s plasma producing gas and ultraviolet rays produced by the plasma excite the fluorescent layers  112  of the display cells to create light. 
     In this case, since several unit sub-fields are included in a unit frame, a desired gradation can be displayed by the display sustaining time of each sub-field. 
       FIG. 3  illustrates a common drive device for the PDP  1  of  FIG. 1 . 
     Referring to  FIG. 3 , a common PDP drive device includes an image processor  300 , a logic controller  302 , an address driver  306 , an X driver  308 , and a Y driver  304 . The image processor  300  converts an external analog image signal to a digital signal and creates an internal image signal, for example, 8 bit red (R), green (G), and blue (B) image data, a clock signal, and vertical and horizontal synchronizing signals. The logic controller  302  creates drive control signals (S A , S Y , S X ) according to the internal image signals coming from the image processor  300 . The address driver  306  processes the address signals (S A ) to create display data signals and applies these display data signals to the address electrode lines (A 1 , A 2 , . . . , Am). The X driver  308  processes the X drive control signal (S X ) and applies it to the X electrode lines. The Y driver  304  processes a Y drive control signal (S Y ) and applies it to the Y electrode lines. 
       FIG. 4  shows a plan view of one example of the panel shown in  FIG. 1  with a structure including black stripes  416  and transparent electrode lines (Xna, Yna) that are divided in each discharge cell by barrier walls  414  and are formed extending from metal electrode lines (Xnb, Ynb). The electrode structure illustrated in  FIG. 4  may obtain a highly efficient discharge by eliminating unnecessary parts of the transparent electrode line (Xna, Yna) that are located on the barrier walls  414 . Additionally, black stripes  416  can be included in the spaces between unit cells to enhance display panel contrast. 
     With the address electrode  500  structure shown in  FIG. 5   a , in order to increase the width of the discharge surface (C) at which the address electrode  500  and scanning (Y) electrode cross each other, the address electrode  500  width must be increased correspondingly. However, increasing the width of the address electrode increases the power needed for addressing discharge cells. This is the cause of high power consumption when presenting low gradation and reproducing moving pictures. 
     A protruded address electrode structure as shown in  FIG. 5   b  may be provided to solve such problems. A protrusion  504  is included to function during address discharge and is located on the discharge surface where the address electrode (A) and scanning (Y) electrode cross each other. Additionally, address electrode portions other than the protrusion  504  are made of a relatively thin conductor material. Therefore, in addition to securing a sufficient address discharge area for stable discharge, the overall power consumption may be maintained. However, in the electrode structure of  FIG. 5   b , since the protrusions  504  are formed in parallel along the scanning electrode (Y), neighboring address electrodes may create electrical interference in an area indicated by reference number  506 . 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to a display panel including an improved electrode structure that substantially obviates one or more of the problems due to limitations and disadvantages of the related art. 
     The present invention provides a display including an improved protruded electrode structure reducing power consumption and providing a stable discharge quality. 
     Additional features of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. 
     The present invention discloses a display panel comprising a plurality of first electrodes that cross a plurality of second electrodes to form cross regions at which display cells are formed. First electrode protrusions are formed at the cross regions in a direction of an arrangement of the second electrode. The first electrode protrusions are differently arranged at adjacent cross regions. 
     The present invention also discloses a display panel including an electrode structure in which a plurality of first and second electrodes cross each other forming cross regions at which respective display cells are formed. The display panel includes protrusions which are respectively formed at the cross regions in the direction of the arrangement of the second electrodes and the protrusions have different forms for every predetermined number of the second electrodes. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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. 
         FIG. 1  shows the structure of a typical three-electrode surface discharging type plasma display panel (PDP). 
         FIG. 2  shows an operation of a cell of a panel shown in  FIG. 1 . 
         FIG. 3  shows a typical drive mechanism for the PDP shown in  FIG. 1 . 
         FIG. 4  shows a plan view of one example of an electrode structure for the panel shown in  FIG. 1 . 
         FIG. 5   a  shows a stripe type address electrode structure. 
         FIG. 5   b  shows a protruded type address electrode structure. 
         FIG. 6  shows a timing diagram illustrating one example of the drive signal created by the ADS driving method of the display panel shown in  FIG. 1  and  FIG. 2 . 
         FIG. 7  shows a plan view of an electrode structure of a display panel according to an exemplary embodiment of the present invention. 
         FIG. 8  shows a plan view of an electrode structure of a display panel according to a second exemplary embodiment of the present invention. 
         FIG. 9  shows a plan view of an electrode structure of a display panel according to a third exemplary embodiment of the present invention. 
         FIG. 10  shows an electrode structure of an upper drive type PDP that may be applied to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will be described in detail with reference to exemplary embodiments of the structure of the display panel and function thereof illustrated with reference to the accompanying drawings. 
     For convenience, the description of exemplary embodiments of the present invention is made with reference to a three-electrode surface discharging type AC PDP. Additionally, the description is based on an address electrode of an AC PDP that includes a protruding portion according to exemplary embodiments of the present invention. 
       FIG. 6  shows an example of drive signal timing according to the address display separated (ADS) driving method of the display panel shown in  FIG. 1  and  FIG. 2 .  FIG. 6  shows drive signals being applied to an address electrode (A), a common electrode (X), and scanning electrodes (Y 1 ˜Yn) within a sub-field (SF). Referring to  FIG. 6 , one sub-field (SF) includes a reset period (PR), an address period (PA), and a discharge-sustaining period (PS). 
     The reset period (PR), which is carried out before going into the address period, initializes the cells&#39; wall charge state by applying a reset pulse to the scanning line of all groups. The reset period (PR) is carried out across the entire screen, thereby forming a uniform wall charge arrangement for all cells. During the address period, a bias voltage (Ve) is applied to the common electrode (X), and a display cell is selected by simultaneously turning on its corresponding scanning electrode (Y 1 ˜Yn) and address electrode (A 1 ˜Am). After the address period (PA), a discharge-sustaining period (PS) is carried out by alternately applying a discharge sustaining pulse (Vs) to the common electrode (X) and the scanning electrodes (Y 1 ˜Yn). During the discharge-sustaining period (PS), a low level voltage (VG) is applied to the address electrodes (A 1 ˜Am).  FIG. 6  shows drive signals in which the reset period (PR), address period (PA), and discharge-sustaining period (PS) are carried out as one group in a sub-field. However, a sub-field may be divided into separate groups that may be individually carried out. For example, by dividing scanning electrodes (Y 1 ˜Yn) into separate groups, the reset periods (PR), address periods (PA), and discharge sustaining periods (PS) may be carried out by each group. Furthermore, by including a plurality of common electrodes (X), discharge-sustaining periods (PS) may be carried out by each group. 
     For stable addressing, a wider discharge surface (C), at which an address electrode (A) and scanning electrode (Y) cross, may be required. 
       FIG. 7  shows a plan view of a display panel electrode structure according to an exemplary embodiment of the present invention. The protrusion  700  of  FIG. 7  is similar to the protrusion  504  of  FIG. 5   b  in that it has a square shape, but the protrusions  700  of  FIG. 7  are not arranged in a straight line. In other words, the line  704  connecting the geometric centers  702  of the protrusions  700  is in a zigzag form and not straight. The structure of the protrusions  700  of  FIG. 7  may reduce the electrical interference between adjacent address electrodes. 
       FIG. 8  shows a plan view of a display panel electrode structure according to a second exemplary embodiment of the present invention. Unlike  FIG. 7 , the protrusions  800  are hexagonal. Similar to  FIG. 7 , the protruding units  800  are not parallel in their arrangement along the direction of the Y electrode. In other words, the connecting line  804  of the geometric centers  802  is in a zigzag form and not straight. Each protruding unit  800  is placed in a position symmetric to the other with respect to the bisector point of the connecting line of the geometric centers between adjacent cells. The form and arrangement of the structure of the protruding units  800  illustrated in  FIG. 8  may enable stable addressing by enlarging the discharge surface while reducing electrical interference. 
       FIG. 9  shows a plan view of a display panel electrode structure according to a third exemplary embodiment of the present invention. The shape of the protrusion  900  is a trapezoid. Similar to the embodiments described above, the line  904  connecting the geometric centers  902  of each protruding unit  900  is in a zigzag form, rather than being a straight line parallel to the scanning electrode (Y). Each protruding unit  900  is placed in a position symmetric to the other with respect to the bisector point of the line connecting the geometric centers between adjacent cells. The form and arrangement of the structure of the protruding units  900  illustrated in  FIG. 9  may enable stable addressing by enlarging the discharge surface while reducing electrical interference. 
     Address electrode protrusions may be formed in a layer on top of the address electrode. Preferably, the protrusions are coplanar with the address electrode. 
     While exemplary embodiments of the present invention are described in terms of a surface discharge type AC PDP, the invention is not limited thereto. The present invention may be applicable to any display device that includes an electrode structure in which a panel displays images by the mutual drive of drive electrodes placed on facing substrates. It is obvious to those skilled in the art that the technology of the present invention may be utilized in other display panels such as, DC PDPs, electroluminescence displays (ELD), liquid crystal displays (LCD), and field emission displays (FED). 
     Furthermore, the above-described exemplary embodiments of the present invention are based on the front driving method of a surface discharging type AC PDP, in which the address electrodes are formed on the lower substrate and scanning electrodes are formed on the upper substrate as shown in  FIG. 1  and  FIG. 2 . However, it is conceivable that the electrode structure of the present invention may be applicable to an upper driving method of a surface discharging type AC PDP as shown in  FIG. 10 , in which address electrodes (A) and scanning electrodes (Y) are formed on the same substrate  106   a  with dielectric bodies  110   a  and  102   a  interposed therebetween. 
     Additionally, the above-described exemplary embodiments of the present invention are described in terms of stripe shaped scanning (Y) electrodes and common (X) electrodes. Yet, the present invention may also apply to various types of scanning (Y) electrode structures and common (X) electrode structures, such as the electrode structure of  FIG. 4 . 
     As described above, according to the display panel of the present invention, the discharge surface formed where the scanning electrodes and address electrodes cross may be increased while maintaining appropriate intervals between the address electrodes. Therefore, stable addressing may be possible while reducing electrical interference among adjacent cells. 
     It will be apparent to those skilled in the art that various modifications and variation can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.