Abstract:
A display device in which charge damage occurring at wiring near the periphery is prevented or reduced, and wiring is facilitated during manufacturing by controlling an angle of an edge part of the wiring near the periphery. A display device includes a substrate, a pixel region including a plurality of unit pixels formed on the substrate. A power supply voltage line supplies a power supply voltage to the pixel region, and a cathode voltage line supplies a cathode voltage to the pixel region. The power supply voltage line includes an edge part formed in an obtuse angle. The edge part of wiring adjacent to the power supply voltage line may also be formed in an obtuse angle. Further, a cathode voltage line and a scan driver each may include an edge part formed in an obtuse angle. The display device may be an organic electroluminescent display device.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority to and the benefit of Korean Patent Application No. 2003-71594, filed on Oct. 14, 2003, the entire disclosure of which is incorporated herein by reference in its entirety.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to an organic electroluminescent display device, and more particularly, to an organic electroluminescent display device in which charge damage occurring at wiring near the periphery is prevented or reduced, and wiring is facilitated during manufacturing by controlling an angle of an edge part of the wiring near the periphery.  
         [0004]     2. Description of Related Art  
         [0005]     Display devices using light emitting elements including organic electroluminescent (EL) device have actively been developed lately. The organic EL device is suitable for a display device having a thin profile and enhanced viewing angles since backlight required in liquid crystal display devices is not required as the organic EL device is a self-emitting display device.  
         [0006]     A type of organic EL device has a structure in which an organic thin film layer is formed between the anode that is a transparent electrode such as ITO and the cathode fabricated using a metal having low work function such as Ca, Li and Al. When a forward voltage is applied to the organic EL device, holes and electrons are respectively injected from the anode and the cathode, the injected holes and electrons are combined to form excitons, and the excitons are emitted and recombined to cause electroluminescence.  
         [0007]     An organic electroluminescent display device  100  using the above-referenced organic EL device is illustrated in  FIG. 1 , which is a plan view for showing a conventional organic electroluminescent display device.  
         [0008]     The organic electroluminescent device  100  includes an upper power supply voltage line  110 , a lower power supply voltage line  120 , a cathode voltage line  130 , a scan driver  140 , a data driver  150 , an active power supply voltage line  160  and a pixel region  170 .  
         [0009]     As illustrated in  FIG. 1 , the organic electroluminescent display device  100  includes the pixel region  170  on which unit pixels emitted in certain colors are arranged at a central part. The upper and lower power supply voltage lines  110 ,  120  supply a power supply voltage from upper and lower sides, respectively, of the pixel region  170 . The scan driver  140  applies a selection signal to one side of the pixel region  170 , and the cathode voltage line  130  transmits a cathode voltage to the other side of the pixel region  170 . The data driver  150  applies a data signal to the pixel region  170  from a location below the lower power supply voltage line  120 .  
         [0010]     In the organic electroluminescent display device  100 , a power supply voltage is applied to the pixel region  170  through the active power supply voltage line  160  from the upper power supply voltage line  110  and the lower power supply voltage line  120 . Further, a cathode voltage is applied to the pixel region  170  from the cathode voltage line  130 . When a selection signal and a data signal are applied from the scan driver  140  and the data driver  150 , respectively, driving circuits formed at unit pixels are switched on so that a certain image is displayed on the pixel region  170  by applying currents corresponding to the power supply voltage and the data signal to organic EL devices (not illustrated in  FIG. 1 ) formed at the pixel region  170 .  
         [0011]     The organic electroluminescent display device  100  is wired with a plurality of power supply lines and signal lines so that a certain power supply is supplied to the scan driver  140  and the data driver  150  to drive the organic EL devices. A part A of  FIG. 1  is described below as one example of wiring and arrangement near the periphery of a conventional organic electroluminescent display device.  
         [0012]      FIG. 2  is an expanded plan view of the part A of  FIG. 1 .  
         [0013]     As seen in  FIG. 2 , a signal line  141 , a scan driver power supply voltage line  142  and a scan driver cathode voltage line  143  are formed near the upper power supply voltage line  110 . The scan driver cathode voltage line  143  may also be referred to as a ground voltage line or a grounding voltage line.  
         [0014]     The upper power supply voltage line  110  is bent at a perpendicular angle, and has edge parts located at corners where the horizontal portion of the upper power supply voltage line  110  is connected to the vertical portions of the upper power supply voltage line  110 . The signal line  141  is arranged along the upper power supply voltage line  110  and is similarly bent at a perpendicular angle. Further, the power supply voltage line  142  and the scan driver cathode voltage line  143  for transmitting a power supply voltage to the scan driver  140  are formed at an inner side of the signal line  141 . It can be seen in  FIG. 2  that the power supply voltage line  142  and the scan driver cathode voltage line  143  are parallel to each other and run adjacently to each other along the vertical portion of the power supply voltage line  142 .  
         [0015]     In a conventional organic electroluminescent display device, a power supply voltage line is wired near the periphery and has a width wider than other wirings in consideration of the voltage drop. However, since respective edge parts of conventional power supply voltage line and other wirings are perpendicularly wired in the same direction, the length of the conventional power supply voltage line and other wirings is increased, and charges are accumulated on edge parts during manufacturing process due to charge characteristics. In other words, the smaller the angle of the edge parts and the sharper edges are, the easier charges are accumulated on the edge parts. Therefore, the conventional organic electroluminescent display device suffers from a disorder occurred by charge damage to inner wirings and metal patterns since charges are distributed between adjacent wirings having the edge parts bent in the same direction according to the degree of accumulation of the charges. In addition, wirings are not easily arranged in the conventional organic electroluminescent display device because the edge parts are perpendicularly constructed so that space efficiency is reduced.  
       SUMMARY OF THE INVENTION  
       [0016]     Therefore, in order to solve the foregoing problems in the conventional organic electroluminescent display device, in exemplary embodiments of the present invention, charges between adjacent wirings are substantially uniformly distributed in an organic electroluminescent display device by generally rounding the wirings near the periphery and bending the generally rounded wirings to a certain angle, thereby relieving the degree of accumulation of the charges on edge parts, and increasing arrangement efficiency of wirings and metal patterns by generally rounding the edge parts.  
         [0017]     In an exemplary embodiment of the present invention, a display device includes a substrate, a pixel region including a plurality of pixels formed on the substrate, a power supply voltage line for supplying a power supply voltage to the pixel region, and a cathode voltage line for supplying a cathode voltage to the pixel region. The power supply voltage line includes an edge part formed in an obtuse angle. An edge part of wiring adjacent to the edge part of the power supply voltage line may be formed in an obtuse angle. The cathode voltage line may also include an edge part formed in an obtuse angle. In addition, the scan driver may include an edge part formed in an obtuse angle. The edge parts may be formed in an obtuse angle of more than 90 degrees. The display device may be an organic electroluminescent display device.  
         [0018]     In another exemplary embodiment of the present invention, a display device includes a pixel region including a plurality of pixels, a power supply voltage line for supplying a power supply voltage to the pixel region, a cathode voltage line for supplying a cathode voltage to the pixel region, a signal line adjacent to the power supply voltage line, a scan driver power supply line for transmitting a power supply voltage to a scan driver, and a scan driver cathode voltage line for transmitting the cathode voltage to the scan driver. The power supply voltage line includes an edge part formed in a generally rounded shape. The cathode voltage line and the scan driver each may include an edge part formed in a generally rounded shape. In addition, the signal line may include an edge part formed in a generally rounded shape. Further, the scan driver power supply line may include an edge part formed in a generally rounded shape. Further, the scan driver cathode voltage line may include an edge part formed in a generally rounded shape. The display device may be an organic electroluminescent display device.  
         [0019]     In yet another exemplary embodiment of the present invention, a display device includes a pixel region and a power supply voltage line for supplying a power supply voltage to the pixel region. The power supply voltage line has a substantially horizontal portion having a first end and a second end, a substantially vertical portion, and an edge part interconnecting the first end of the substantially horizontal portion and the substantially vertical portion. The edge part forms an obtuse angle with both the substantially horizontal portion and the substantially vertical portion.  
         [0020]     In yet another exemplary embodiment of the present invention, a display device includes a pixel region having a plurality of pixels formed thereon, and a power supply voltage line for supplying a power supply voltage to the pixel region. The power supply voltage line has a substantially horizontal portion, a first substantially vertical portion, a second substantially vertical portion, a first edge part interconnecting a first end of the substantially horizontal portion and the first substantially vertical portion, and a second edge part interconnecting a second end of the substantially horizontal portion and the second substantially vertical portion. A cathode voltage line is disposed proximate to and substantially parallel to the second substantially vertical portion. The cathode voltage line supplies a cathode voltage to the pixel region, and has an edge part located at a corner proximate to the second edge part and formed in an angle and direction which is generally the same as that of the second edge part. A scan driver is disposed proximate to and substantially parallel to the first substantially vertical portion. The scan driver supplies a selection signal to the pixel region, and has an edge part located at a corner proximate to the first edge part and formed in substantially the same direction as and at an angle which is generally the same as that of the first edge part. A scan driver cathode voltage line is disposed proximate to and substantially parallel to the scan driver. The scan driver cathode voltage line transmits a scan driver cathode voltage to the scan driver, and has an edge part located at a corner proximate to the first edge part and formed in substantially the same direction as and at an angle which is generally the same as that of the first edge part. A scan driver power supply line is disposed proximate to and substantially parallel to the scan driver. The scan driver power supply line transmits a scan driver power supply voltage to the scan driver, and has an edge part located at a corner proximate to the first edge part and formed in substantially the same direction as and at an angle which is generally the same as that of the first edge part. A signal line is disposed adjacent to the power supply voltage line, and has a substantially horizontal portion, a substantially vertical portion and an edge part interconnecting therebetween. The edge part of the signal line is adjacent to the first edge part and formed in substantially the same direction as and at an angle which is generally the same as that of the first edge part. The first edge part forms an obtuse angle with both the substantially horizontal portion and the first substantially vertical portion of the power supply voltage line. The second edge part forms an obtuse angle with both the substantially horizontal portion and the second substantially vertical portion of the power supply voltage line. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]     The above and other features of the present invention will become more apparent to those of ordinary skill in the art with the following description in detail of certain exemplary embodiments thereof with reference to the attached drawings in which:  
         [0022]      FIG. 1  is a plan view showing a conventional organic electroluminescent display device;  
         [0023]      FIG. 2  is an expanded plan view of a part A of  FIG. 1 ;  
         [0024]      FIG. 3  is a plan view showing an exemplary embodiment according to the present invention;  
         [0025]      FIG. 4  is an expanded plan view of a part B of  FIG. 3 ;  
         [0026]      FIG. 5  is a plan view showing another exemplary embodiment according to the present invention; and  
         [0027]      FIG. 6  is an expanded plan view of a part D of  FIG. 5 . 
     
    
     DETAILED DESCRIPTION  
       [0028]     The present invention will now be described in detail in connection with certain exemplary embodiments with reference to the accompanying drawings. In the drawings, like reference numerals/characters designate like elements.  
         [0029]      FIG. 3  is a plan view showing one exemplary embodiment of the present invention.  
         [0030]     An organic electroluminescent display device  200  includes an upper power supply voltage line  210 , a lower power supply voltage line  220 , a cathode voltage line  230 , a scan driver  240 , a data driver  250 , an active power supply voltage line  260  and a pixel region  270  having a plurality of unit pixels for emitting light of certain colors, formed on a substrate.  
         [0031]     In  FIG. 3 , edge parts of the upper power supply voltage line  210  in both parts B, C are formed in an obtuse angle having more than 90 degrees. Additionally, edge parts on wirings adjacent to the edge parts of the upper power supply voltage line  210  should also be formed in an obtuse angle as shown in  FIG. 4 .  
         [0032]     While  FIG. 4  only shows an expanded plan view of the part B, the expanded plan view of the part C would have edge parts formed in an obtuse angle in the same manner as the part B. By way of example, an edge part at the upper right corner of the cathode voltage line  230  is formed to have the same or similar angle in the same direction as the adjacent edge part of the upper power supply voltage line  210  as shown in  FIG. 3 . In addition, an edge part at the upper left corner of the scan driver  240  is formed to have the same or a similar angle in the same direction as the adjacent edge part of the upper power supply voltage line  210  as shown in  FIG. 3 .  
         [0033]     Further, wirings disposed between the scan driver  240  and the upper power supply voltage line  210  also should include edge parts formed in the same or similar obtuse angle as in the edge part of the upper power supply voltage line  210  as illustrated in  FIG. 4 .  
         [0034]      FIG. 4  is an expanded plan view of the part B of  FIG. 3 .  
         [0035]     The upper power supply voltage line  210  has an upper power supply voltage line edge part  210   a . A signal line  241  has a signal line edge part  241   a , a scan driver power supply line  242  has a power supply line edge part  242   a , and a scan driver cathode voltage line  243  has a cathode voltage line edge part  243   a . The scan driver cathode voltage line  243  may also be referred to as a ground voltage line or a grounding voltage line.  
         [0036]     As illustrated in  FIG. 4 , the edge part  210   a  of the upper power supply voltage line  210  of the organic electroluminescent display device  200  is formed in an obtuse angle. The signal line  241  includes the edge part  241   a  formed in an obtuse angle in the same direction as the power supply voltage line edge part  210   a . The signal line  241  is arranged along the upper power supply voltage line  210  inside the edge part  210   a  of the upper power supply voltage line  210 . Further, the power supply voltage line  242  and the scan driver cathode voltage line  243  that transmit a power supply to the scan driver  240  include edge parts  242   a ,  243   a  at their upper left corners, respectively, formed inside the signal line  241  in an obtuse angle in the same direction as the edge part  241   a  of the signal line  241 .  
         [0037]     For example, the edge part  210   a  of the upper power supply voltage line  210  should be formed in a generally rounded shape, wherein the edge part  210   a  is gently formed in a generally rounded shape and a large obtuse angle so that the degree of accumulation of the charges is reduced because of the characteristics of charges, which dictates that as an edge of the edge part of the upper power supply voltage line  210  becomes smaller and sharper, the degree of accumulation of charges increases.  
         [0038]     While the edge part  210   a  shown in  FIG. 4  as well as other edge parts in  FIGS. 3 and 4  are not truly rounded or have a curvature of a curve, it may be referred to as being generally rounded in a sense that its obtuse angles are less sharp as compared to the perpendicular angles of the edge parts of the conventional organic electroluminescent display device. In other embodiments, the upper power supply voltage line as well as other wirings may have generally rounded edge parts or edge parts having different obtuse angles than those shown in  FIGS. 3 and 4 .  
         [0039]     Further, conventional loss of inner wirings and metal patterns through charge damage is prevented or reduced by forming the edge parts  210   a ,  241   a ,  242   a ,  243   a  of wirings such as the upper power supply voltage line  210 , the signal line  241 , the scan driver power supply line  242  and the cathode voltage line  243  in a generally rounded or other shape having an obtuse angle, thereby slowing down charge difference between the wirings. Additionally, the edge parts  210   a ,  241   a ,  242   a ,  243   a  each having an obtuse angle are desirable when voltage drop is considered because the length of the wirings are shortened by forming the obtuse angle.  
         [0040]     Further, wirings and other required components can be easily arranged by forming the edge parts  210   a ,  241   a ,  242   a ,  243   a  of respective wirings in an obtuse angle greater than 90 degrees so that an empty space without metal is formed on the substrate.  
         [0041]      FIG. 5  is a plan view showing another exemplary embodiment of the present invention.  
         [0042]     An organic electroluminescent display device  300  includes an upper power supply voltage line  310 , a lower power supply voltage line  320 , a cathode voltage line  330 , a scan driver  340 , a data driver  350 , an active power supply voltage line  360  and a pixel region  370  having a plurality of unit pixels for emitting light of certain colors, formed on a substrate.  
         [0043]     In  FIG. 5 , edge parts of the upper power supply voltage line  310  in both parts D, E are generally rounded. Additionally, edge parts on wirings adjacent to the edge parts of the upper power supply voltage line  310  should also be rounded as shown in  FIG. 6 .  
         [0044]     While  FIG. 6  only shows an expanded plan view of the part D, the expanded plan view of the part E would have generally rounded edge parts formed in the same manner as the part D. By way of example, an edge part at the upper right corner of the cathode voltage line  330  is generally rounded in a similar manner as the adjacent edge part of the upper power supply voltage line  310  as shown in  FIG. 5 . In addition, an edge part at the upper left corner of the scan driver  340  is generally rounded in a similar manner as the as adjacent edge part of the upper power supply voltage line  310  as shown in  FIG. 5 .  
         [0045]     Further, wirings disposed between the scan driver  340  and the upper power supply voltage line  310  also should include edge parts formed to have a generally rounded shape as in the edge part of the upper power supply voltage line  310  as illustrated in  FIG. 6 .  
         [0046]      FIG. 6  is an expanded plan view of the part D of  FIG. 5 .  
         [0047]     The upper power supply voltage line  310  has an upper power supply voltage line edge part  310   a . A signal line  341  has a signal line edge part  341   a , a scan driver power supply line  342  has a power supply line edge part  342   a , and a scan driver cathode voltage line  343  has a cathode voltage line edge part  343   a . The scan driver cathode voltage line  343  may also be referred to as a ground voltage line or a grounding voltage line.  
         [0048]     As illustrated in  FIG. 6 , the edge part  310   a  of the upper power supply voltage line  310  of the organic electroluminescent display device  300  is formed to have a generally rounded shape. The signal line  341  includes the edge part  341   a  formed in a generally rounded shape in a similar manner as the power supply voltage line edge part  310   a . The signal line  341  is arranged along the upper power supply voltage line  310  inside the edge part  310   a  of the upper power supply voltage line  310 . Further, the power supply voltage line  342  and the scan driver cathode voltage line  343  that transmit a power supply to the scan driver  340  include edge parts  342   a ,  343   a  at their upper left corners, respectively, formed inside the signal line  341  in a generally rounded shape in a similar manner as the edge part  341   a  of the signal line  341 .  
         [0049]     For example, the edge part  310   a  of the upper power supply voltage line  310  should be formed in a generally rounded shape, wherein the edge part  310   a  is gently formed in a generally rounded shape so that the degree of accumulation of the charges is reduced because of the characteristics of charges, which dictates that as an edge of the edge part of the upper power supply voltage line  310  becomes smaller and sharper, the degree of accumulation of charges increases.  
         [0050]     Conventional loss of inner wirings and metal patterns through charge damage is prevented or reduced by forming the edge parts  310   a ,  341   a ,  342   a ,  343   a  of wirings such as the upper power supply voltage line  310 , the signal line  341 , the scan driver power supply line  342  and the cathode voltage line  343  in a generally rounded shape, thereby slowing down charge difference between the wirings. Additionally, the edge parts  310   a ,  341   a ,  342   a ,  343   a  each having a generally rounded shape are desirable when voltage drop is considered because the length of the wirings are shortened by forming the generally rounded shape.  
         [0051]     Further, wirings and other required components can be easily arranged by forming the edge parts  310   a ,  341   a ,  342   a ,  343   a  of respective wirings in a generally rounded shape so that an empty space without metal is formed on the substrate.  
         [0052]     As described above, the length of the wirings is shortened in an organic electroluminescent display device according to exemplary embodiments of the present invention by forming an edge part of respective wirings formed on the substrate in an obtuse angle. The loss of the wirings and metal patterns due to charge damage is prevented or reduced by reducing the degree of accumulation of charges so that charge difference between the wirings is slowed down. Additionally, wirings are easily arranged, and other components are easily added by forming an obtuse angle on the edge part so that an empty space without metal is formed on the substrate.  
         [0053]     While the invention has been particularly shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention. The scope of the present invention is indicated by the appended claims, and all changes that come within the meaning and range of equivalents thereof are intended to be embraced therein.