Abstract:
An OLED display that is enhanced in mechanical strength by improving a structure of a bezel supporting a panel assembly. The OLED display includes a panel assembly that includes a display region, a pad region, and a plurality of OLEDs arranged in the display region and a bezel coupled to the panel assembly, the bezel including synthetic resin, wherein, when a diagonal length of the display region is in the range of 25.4 to 101.6 mm, the bezel being designed to satisfy the following inequality t≧0.0003×a, where t(mm) is a thickness of the bezel and a(mm 2 ) is an area of the display region

Description:
CLAIM OF PRIORITY 
       [0001]    This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application earlier filed in the Korean Intellectual Property Office on Jan. 14, 2008 and there duly assigned Serial No. 10-2008-0003940. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an organic light emitting diode (OLED) display that is enhanced in mechanical strength by improving the design of a bezel used to support a panel assembly. 
         [0004]    2. Description of the Related Art 
         [0005]    An OLED display includes a plurality of organic light emitting diodes (OLEDs), each diode having a hole injection electrode, an organic light emitting layer, and an electron injection electrode. The OLEDs emit light using energy generated when excitons produced by electron-hole combination in the organic light emitting layer drop from the excitation state to the ground state. 
         [0006]    By the above principle, the OLED displays have a self-emissive characteristic. Therefore, unlike liquid crystal displays (LCDs), the OLED displays do not require a separate light source and thus a thickness and weight thereof can be reduced. Further, the OLED displays have a variety of beneficial properties such as low power consumption, high luminance, quick response, and the like. Therefore, the OLED displays are drawing attention as the upcoming alternative displays for portable electronic devices. 
         [0007]    Generally, a typical OLED display includes a panel assembly in which OLEDs are formed, a bezel coupled to the panel assembly at a rear side of the panel assembly, and a printed circuit board (PCB) electrically connected to the panel assembly by a flexible printed circuit board (FPCB). The panel assembly of the OLED display has two thin substrates. In addition, unlike the LCD in which the interior of a panel assembly is filled with liquid crystal, the OLED display is designed such that empty spaces exist in an inside of the panel assembly. Therefore, mechanical strength of the OLED display is not sufficient. Particularly, a drop impact resistance property of the panel assembly deteriorates with an increase in the size of the panel assembly. 
         [0008]    Therefore, when a user accidentally drops an electronic device having the OLED display, a relatively large torsion load and/or relatively large bending load is applied to the bezel and thus the bezel is deformed. As a result, the torsion load and/or the bending load are transferred to the panel assembly coupled to the bezel. This can cause the damage of the panel assembly. What is therefore needed is a design for an OLED display that is better able to withstand impact. 
         [0009]    The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that is not prior art as per 35 U.S.C. 102. 
       SUMMARY OF THE INVENTION 
       [0010]    An exemplary embodiment of the present invention provides an OLED display that is enhanced in mechanical strength and in drop impact resistance characteristic by improving a design of the bezel coupled to a panel assembly. 
         [0011]    According to an exemplary embodiment of the present invention, an organic light emitting diode (OLED) display includes a panel assembly that includes a display region, a pad region, and a plurality of OLEDs arranged in the display region and a bezel coupled to the panel assembly, the bezel including synthetic resin, wherein, when a diagonal length of the display region is in the range of 25.4 to 101.6 mm, the bezel being designed to satisfy the following inequality t≧0.0003×a, where t(mm) is a thickness of the bezel and a(mm 2 ) is an area of the display region. 
         [0012]    The diagonal length of the display region can be 45.72 mm and the thickness of the bezel can be between 0.3 and 1 mm. The diagonal length of the display region can be 55.88 mm and the thickness of the bezel can be between 0.45 and 1.2 mm. The diagonal length of the display region can be 71.12 mm and the thickness of the bezel can be between 0.73 and 1.5 mm. The diagonal length of the display region can be 76.2 mm and the thickness of the bezel can be between 0.84 and 1.8 mm. The diagonal length of the display region can be 88.9 mm and the thickness of the bezel can be between 1.14 and 2 mm. The diagonal length of the display region can be 99.06 mm and the thickness of the bezel can be between 1.41 and 2.5 mm. 
         [0013]    The bezel can include a bottom portion, the panel assembly being arranged on the bottom portion and sidewalls arranged on side edges of the bottom portion except for a side edge corresponding to the pad region. The display can also include a flexible printed circuit board fixed to the pad region and bent toward a rear surface of the bezel and a printed circuit board electrically connected to the panel assembly by the flexible printed circuit board. 
         [0014]    According to another aspect of the present invention, there is provided an organic light  9  emitting diode (OLED) display that includes a panel assembly including a display region, a pad region, and a plurality of OLEDs arranged in the display region and a bezel coupled to the panel assembly, the bezel including synthetic resin, wherein, when a diagonal length of the display region is in the range of 101.6 to 177.8 mm, the bezel is designed to satisfy the following inequality: t≧0.00024×a, where t(mm) is a thickness of the bezel and a(mm 2 ) is an area of the display region. 
         [0015]    The diagonal length of the display region can be 101.6 mm and the thickness of the bezel can be between 1.1.9 and 3 mm. The diagonal length of the display region can be 127 mm and the thickness of the bezel can be between 1.86 and 4 mm. The diagonal length of the display region can be 152.4 mm and the thickness of the bezel can be between 2.67 and 5 mm. The bezel can include a bottom portion, the panel assembly being arranged on the bottom portion and sidewalls arranged on side edges of the bottom portion except for a side edge corresponding to the pad region. The OLED display can also include a flexible printed circuit board fixed to the pad region and bent toward a rear surface of the bezel and a printed circuit board electrically connected to the panel assembly by the flexible printed circuit board. 
         [0016]    According to still another aspect of the present invention, there is provided an organic light emitting diode (OLED) display that includes a panel assembly that includes a display region, a pad region, and a plurality of OLEDs arranged in the display region and a bezel coupled to the panel assembly, the bezel including synthetic resin, wherein, when a diagonal length of the display region at least 177.8 mm, the bezel is designed to satisfy the following inequality: t≧0.00015×a, where t(mm) is a thickness of the bezel and a(mm 2 ) is an area of the display region. 
         [0017]    The diagonal length of the display region can be 177.8 mm and the thickness of the bezel can be between 2.27 and 5 mm. The diagonal length of the display region can be 203.2 mm and the thickness of the bezel can be between 2.97 and 6 mm. The bezel can include a bottom portion, the panel assembly being arranged on the bottom portion and sidewalls arranged on side edges of the bottom portion except for a side edge corresponding to the pad region. The OLED display can also include a flexible printed circuit board fixed to the pad region and bent toward a rear surface of the bezel and a printed circuit board electrically connected to the panel assembly by the flexible printed circuit board. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    A more complete appreciation of the invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein: 
           [0019]      FIG. 1  is an exploded perspective view of an unassembled OLED display according to an exemplary embodiment of the present invention; 
           [0020]      FIG. 2  is a perspective view of the OLED display of  FIG. 1  upon assembly; 
           [0021]      FIG. 3  is a circuit diagram of a sub-pixel circuit of the panel assembly of  FIG. 1 ; 
           [0022]      FIG. 4  is a partly enlarged cross-sectional view of the panel assembly of  FIG. 1 ; and 
           [0023]      FIG. 5  is a schematic diagram of a drop jig used for a drop impact resistance test. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As those skilled in the art would realize, the described embodiments can be modified in various different ways, all without departing from the spirit or scope of the present invention. 
         [0025]    Turning now to  FIGS. 1 and 2 ,  FIG. 1  is an exploded perspective view of an unassembled OLED display according to an exemplary embodiment of the present invention, and  FIG. 2  is a perspective view of the OLED display of  FIG. 1  after assembly. Referring to  FIGS. 1 and 2 , an OLED display  100  of the present exemplary embodiment includes a panel assembly  20  having a display region A 10  and a pad region A 20  and displaying an image on the display region A 10 , a bezel  40  coupled to the panel assembly  20  at a rear side of the panel assembly  20  and a printed circuit board (PCB)  36  electrically connected to the panel assembly  20  via a flexible printed circuit board (FPCB)  32 . 
         [0026]    The panel assembly  20  includes a first substrate  12  and a second substrate  14  that is smaller than the first substrate  12  and has a peripheral portion coupled to the first substrate  12  by a sealant. The display region A 10  is defined at an overlapping region of the first and second substrates  12  and  14 , the display region A 10  being surrounded by the sealant. The pad region A 20  is defined at an outside of the sealant. 
         [0027]    A plurality of sub-pixels are arranged in a matrix pattern in the display region A 10  on the first substrate  12 . Scan and data drivers (not shown) for driving the sub-pixels are located between the display region A 10  and the sealant or at the outside of the sealant. Pad electrodes (not shown) for transferring electrical signals to the scan and data drivers are located in the pad region A 20  of the first substrate  12 . 
         [0028]    Turning now to  FIGS. 3 and 4 ,  FIG. 3  is a circuit diagram of a sub-pixel circuit of the panel assembly of  FIG. 1 , and  FIG. 4  is a partly enlarged cross-sectional view of a panel assembly of  FIG. 1 . Referring to  FIGS. 3 and 4 , each of the sub-pixels of the panel assembly  20  includes an OLED L 1  and a driving circuit unit. The OLED L 1  includes an anode electrode  16 , an organic light emitting layer  18 , and a cathode electrode  22 . The driving circuit unit includes at least two thin film transistors and at least one storage capacitor C 1 . The thin film transistors include at least one switching transistor T 1  and at least one driving transistor T 2 . 
         [0029]    The switching transistor T 1  is connected to scan and data lines SL 1  and DL 1 . Depending on the voltage inputted from the scan line SL 1 , the switching transistor T 1  transfers data coming from data line DL 1  to the driving transistor T 2 . The storage capacitor C 1  is connected to a power line VDD as well as to the switching transistor T 1  to store a voltage corresponding to a difference between a voltage transferred by the switching transistor T 1  and a voltage supplied by the power line VDD. 
         [0030]    The driving transistor T 2  is connected to both the power line VDD and the storage capacitor C 1  and supplies an output current I OLED  to OLED diode L 1 . Current I OLED  corresponds to a square of a difference between a voltage stored in storage capacitor C 1  and a threshold voltage, and causes OLED diode L 1  to emit light accordingly. The driving transistor T 2  includes a source electrode  24 , a drain electrode  26 , and a gate electrode  28 . The anode electrode  16  of the OLED L 1  is connected to the drain electrode  26  of the driving transistor T 2 . It should be construed that the above-described structure of the sub-pixels is just an example and the present invention is in no way so limited. 
         [0031]    Referring again to  FIGS. 1 and 2 , the second substrate  14  is coupled to the first substrate  12  by the sealant at a predetermined interval to protect the driving circuit unit and the OLEDs on the first substrate  12  from an outer environment. A polarizing plate (not shown) for suppressing reflection of external light can be arranged on an outer surface of the second substrate  14  in the display region A 10 . A moisture absorption agent can be attached to an inner surface of the second substrate  14 . 
         [0032]    An integrated circuit chip  30  is mounted in the pad region A 20  of the panel assembly  20  through a chip-on-glass (COG) method. The FPCB  32  is also mounted in the pad region A 20  of the panel assembly  20  through a chip-on-film (COF) method. A protective layer  34  is formed around the integrated circuit chip  30  and the FPCB  32  to cover and protect pad electrodes formed in the pad region A 20 . 
         [0033]    A variety of electronic elements (not shown) for processing driving signals are mounted on the PCB  36 . A connector  38 , for transferring external signals to the PCB  36 , is also installed on the PCB  36 . The FPCB  32  fixed at the pad region A 20  is folded toward a rear surface of the bezel  40  to face the rear surface of the bezel  40 . 
         [0034]    The bezel  40  includes a bottom portion  42  on which the panel assembly  20  is arranged and sidewalls  44 , which extends from three of the four side edges. On the one remaining side edge of bezel  40 , there is no sidewall. It is at this side edge that the FPCB  32  is bent around to face a rear surface of the bezel  40 . A double-sided adhesive tape  46  is disposed between the bottom portion  42  of the bezel  40  and the panel assembly  20  to fix the panel assembly  20  to the bezel  40 . It should be construed that the above-described structure for the bezel  40  is just an example and can be variously modified and still be within the scope of the present invention. For example, a flange (not shown) for enhancing strength can be formed on the side edge of the bottom portion  42 , at which the FPCB  32  is bent. 
         [0035]    In the present exemplary embodiment, the bezel  40  is made out of synthetic resin having an excellent impact absorption/dispersion property. For example, the bezel  40  can be made out of polymer-based engineering plastic such as polycarbonate. Although the strength of the synthetic resin is less than that of metal, an impact absorption/dispersion property of the synthetic resin is better than that of the metal. Therefore, when the OLED display  100  uses the bezel  40  made out of synthetic resin to support the panel assembly  20 , the panel assembly  20  can be more effectively protected from external impact. 
         [0036]    In accordance with the present exemplary embodiment, by forming the bezel  40  out of synthetic resin, an improved impact absorption/dispersion effect can be obtained. Furthermore, when the OLED display  100  uses the bezel  40  made out of synthetic resin, an overall weight of the OLED display  100  is reduced. Therefore, when the OLED display  100  using the bezel  40  made out of synthetic resin collides with an external object or is dropped on the floor, impact energy generated thereby is relatively small. 
         [0037]    In addition, a thickness of the bezel  40  is designed to vary in accordance with the size of the panel assembly  20  so as to prevent deterioration of a drop impact resistance property even when the size of the panel assembly  20  increases. That is, a thickness t (see  FIG. 1 ) of the bezel  40  increases with the increase of an area of the display region A 10  of the panel assembly  20  to enhance the mechanical strength of the bezel  40 . 
         [0038]    For example, when the OLED display  100  is designed with the display region A 10  having a diagonal length d (see  FIG. 1 ) equal to or greater than 25.4 mm (1 inch) but less than 101.6 mm (4 inches), the bezel  40  is designed to satisfy the following inequality 1: 
         [0000]        t≧ 0.0003 ×a   [Inequality 1] 
         [0000]    where, t(in mm) is the thickness of the bezel  40  and a (in mm 2 ) is the area of the display region A 10 . The thickness t of the bezel  40 , which is obtained by Inequality 1, is a minimum thickness of bezel  40  that can secure a desirable drop impact resistance property. 
         [0039]    A test for determining damage to the panel assembly  20  was performed using the drop jig of  FIG. 5  with the OLED display  100  within, which is designed with the display region A 10  having the diagonal length d equal to or greater than 25.4 mm (1 inch) but less than 101.6 mm (4 inches), to execute a free-fall from a height of 1.5 m. 
         [0040]    Turning now to  FIG. 5 ,  FIG. 5  is a schematic diagram of a drop jig used for the drop impact resistance test. Referring to  FIG. 5 , the drop jig  50  includes an upper case and a lower case. The OLED display is mounted within a space defined by the upper and the lower cases of the drop jig  50 . The drop jig  50  was dropped in first through sixth directions as indicated by the six arrows of  FIG. 5  corresponding to respective sides of the hexahedron drop jig  50 . 
         [0041]    The drop impact resistance test was performed 18 times (3 times for each of the six directions) for one type of OLED display. The drop impact resistance value was calculated by giving 1 point when the panel assembly was not damaged and by giving 0 points when the panel assembly is damaged. The test was repeatedly performed for 10 different OLED displays. The drop impact resistance values shown in the following Tables 1 to 6 are mean values for the 10 different OLED displays. 
         [0042]    First, an OLED display that is designed with a display region having a diagonal length of 45.72 mm (1.8 inch) and an area of 1003.35 mm 2  will be described. In this case, a minimum thickness of the bezel according to Inequality 1 is 0.3 mm. Drop impact resistance test results for bezels having various thicknesses are shown in the following Table 1: 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Examples 
                   
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Thickness of bezel (mm) 
                 0.3 
                 0.4 
                 0.5 
                 0.6 
               
               
                   
                 Mean drop impact 
                 18 
                 18 
                 18 
                 18 
               
               
                   
                 resistance value 
               
               
                   
                   
               
             
          
         
       
     
         [0043]    A possible minimum thickness of the bezel made out of the synthetic resin is 0.3 mm. Table 1 shows that all the examples (4 different OLED displays) having a diagonal length of 45.72 mm and a bezel thickness equal to or greater than 0.3 mm have a mean drop impact resistance value of 18. This means that all the examples have excellent drop impact strength. 
         [0044]    An OLED display that is designed with a display region having a diagonal length of 55.88 mm (2.2 inches) and an area of 1498.83 mm 2  will be described. In this case, a minimum thickness of the bezel according to Inequality 1 is 0.45 mm. Drop impact resistance test results for bezels having various thicknesses are shown in the following Table 2: 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Comparative Examples 
                 Examples 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Thickness of bezel 
                 0.35 
                 0.4 
                 0.45 
                 0.55 
                 0.65 
                 0.75 
               
               
                 (mm) 
               
               
                 Mean drop impact 
                 14 
                 16 
                 18 
                 18 
                 18 
                 18 
               
               
                 resistance value 
               
               
                   
               
             
          
         
       
     
         [0045]    Next, an OLED display that is designed with a display region having a diagonal length of 71.12 mm (2.8 inches) and an area of 2427.87 mm 2  will be described. In this case, a minimum thickness of the bezel according to Inequality 1 is 0.73 mm. Drop impact resistance test results for bezels having various thicknesses are shown in the following Table 3: 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 Comparative Examples 
                 Examples 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Thickness of bezel 
                 0.53 
                 0.63 
                 0.73 
                 0.83 
                 0.93 
                 1.03 
               
               
                 (mm) 
               
               
                 Mean drop impact 
                 12 
                 16 
                 18 
                 18 
                 18 
                 18 
               
               
                 resistance value 
               
               
                   
               
             
          
         
       
     
         [0046]    Next, an OLED display that is designed with a display region having a diagonal length of 76.2 mm (3 inches) and an area of 2787.1 mm 2  will be described. In this case, a minimum thickness of the bezel according to Inequality 1 is 0.84 mm. Drop impact resistance test results for bezels having various thicknesses are shown in the following Table 4: 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                 Comparative Examples 
                 Examples 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Thickness of bezel 
                 0.64 
                 0.74 
                 0.84 
                 0.94 
                 1.04 
                 1.14 
               
               
                 (mm) 
               
               
                 Mean drop impact 
                 12 
                 16 
                 18 
                 18 
                 18 
                 18 
               
               
                 resistance value 
               
               
                   
               
             
          
         
       
     
         [0047]    Next, an OLED display that is designed with a display region having a diagonal length of 88.9 mm (3.5 inches) and an area of 3793.54 mm 2  will be described. In this case, a minimum thickness of the bezel according to Inequality 1 is 1.14 mm. Drop impact resistance test results for bezels having various thicknesses are shown in the following Table 5: 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 5 
               
               
                   
                   
               
               
                   
                 Comparative Examples 
                 Examples 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Thickness of bezel 
                 0.94 
                 1.04 
                 1.14 
                 1.24 
                 1.34 
                 1.44 
               
               
                 (mm) 
               
               
                 Mean drop impact 
                 13 
                 15 
                 18 
                 18 
                 18 
                 18 
               
               
                 resistance value 
               
               
                   
               
             
          
         
       
     
         [0048]    Next, an OLED display that is designed with a display region having a diagonal length of 99.06 mm (3.9 inches) and an area of 4710.18 mm 2  will be described. In this case, a minimum thickness of the bezel according to Inequality 1 is 1.41 mm. Drop impact resistance test results for bezels having various thicknesses are shown in the following Table 6: 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 6 
               
               
                   
                   
               
               
                   
                 Comparative Examples 
                 Examples 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Thickness of bezel 
                 1.21 
                 1.31 
                 1.41 
                 1.51 
                 1.61 
                 1.71 
               
               
                 (mm) 
               
               
                 Mean drop impact 
                 14 
                 16 
                 18 
                 18 
                 18 
                 18 
               
               
                 resistance value 
               
               
                   
               
             
          
         
       
     
         [0049]    As shown in Tables 1 to 6, when the OLEDs are designed with the display region A 10  having a diagonal length equal to or greater than 25.4 mm but less than 101.6 mm have a bezel with a minimum thickness satisfying Inequality 1, the mean drop impact resistance values thereof are 18, which means that the impact strength is excellent. 
         [0050]    Meanwhile, as the thickness of the bezel  40  increases, an overall thickness of the OLED display  100  increases. This makes it difficult to make the OLED display slim. An allowable maximum thickness of the bezel  40  for a slim mobile device in accordance with variation of the diagonal length of the display region is shown in the following Table 7: 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
                 TABLE 7 
               
               
                   
                   
               
               
                   
                 Diagonal Length of Display 
                 Allowable Maximum Thickness 
               
               
                   
                 Region (mm) 
                 of Bezel (mm) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 45.72 
                 1 
               
               
                   
                 55.88 
                 1.2 
               
               
                   
                 71.12 
                 1.5 
               
               
                   
                 76.2 
                 1.8 
               
               
                   
                 88.9 
                 2 
               
               
                   
                 99.06 
                 2.5 
               
               
                   
                   
               
             
          
         
       
     
         [0051]    Optimal thickness ranges of the bezels having various display region sizes can be represented as shown in the following Table 8 in accordance with Inequality 1 and results of Table 7: 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
                 TABLE 8 
               
               
                   
                   
               
               
                   
                 Diagonal Length of Display 
                 Optimal Thickness 
               
               
                   
                 Region (mm) 
                 of Bezel (mm) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 45.72 
                 0.3~1  
               
               
                   
                 55.88 
                 0.45~1.2 
               
               
                   
                 71.12 
                 0.73~1.5 
               
               
                   
                 76.2 
                 0.84~1.8 
               
               
                   
                 88.9 
                 1.14~2   
               
               
                   
                 99.06 
                 1.41~2.5 
               
               
                   
                   
               
             
          
         
       
     
         [0052]    Next, when the OLED display  100  is designed with the display region A 10  having a diagonal length d equal to or greater than 101.6 mm (4 inches) but less than 177.8 mm (7 inches), the bezel  40  is designed to satisfy the following Inequality 2: 
         [0000]        t≧ 0.00024 ×a   [Inequality 2] 
         [0053]    where, t(mm) is the thickness of the bezel  40  and a(mm 2 ) is the area of the display region A 10 . The thickness t of the bezel  40 , which is obtained by Inequality 2, is a minimum thickness the bezel  40  that can secure a desirable drop impact resistance property. 
         [0054]    A test for determining damage of the panel assembly  20  was performed by allowing the drop jig of  FIG. 5  with the OLED display  100  within, which is designed with the display region A 10  having the diagonal length d equal to or greater than 101.6 mm but less than 177.8 mm, to execute a free-fall from a height of 1.2 m. Except for this change in drop height, this drop impact resistance test was the same as that performed to produce the results of tables 1-6 above. 
         [0055]    First, an OLED display that is designed with a display region having a diagonal length of 101.6 ml (4 inches) and an area of 4954.83 mm 2  will be described. In this case, a minimum thickness of the bezel according to Inequality 2 is 1.19 mm. Drop impact resistance test results for bezels having various thicknesses are shown in the following Table 9: 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 9 
               
               
                   
                   
               
               
                   
                 Comparative Examples 
                 Examples 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Thickness of bezel 
                 0.99 
                 1.09 
                 1.19 
                 1.29 
                 1.39 
                 1.49 
               
               
                 (mm) 
               
               
                 Mean drop impact 
                 12 
                 15 
                 18 
                 18 
                 18 
                 18 
               
               
                 resistance value 
               
               
                   
               
             
          
         
       
     
         [0056]    Next, an OLED display that is designed with a display region having a diagonal length of 127 mm (5 inches) and an area of 7741.92 mm 2  will be described. In this case, a minimum thickness of the bezel according to Inequality 2 is 1.86 mm. Drop impact resistance test results for bezels having various thicknesses are shown in the following Table 10: 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 10 
               
               
                   
                   
               
               
                   
                 Comparative Examples 
                 Examples 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Thickness of bezel 
                 1.66 
                 1.76 
                 1.86 
                 1.96 
                 2.06 
                 2.16 
               
               
                 (mm) 
               
               
                 Mean drop impact 
                 13 
                 16 
                 18 
                 18 
                 18 
                 18 
               
               
                 resistance value 
               
               
                   
               
             
          
         
       
     
         [0057]    Next, an OLED display that is designed with a display region having a diagonal length of 152.4 mm (6 inches) and an area of 11148.36 mm 2  will be described. In this case, a minimum thickness of the bezel according to Inequality 2 is 2.67 mm. Drop impact resistance test results for bezels having various thicknesses are shown in the following Table 11: 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 11 
               
               
                   
                   
               
               
                   
                 Comparative Examples 
                 Examples 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Thickness of bezel 
                 2.48 
                 2.57 
                 2.67 
                 2.77 
                 2.87 
                 2.97 
               
               
                 (mm) 
               
               
                 Mean drop impact 
                 14 
                 16 
                 18 
                 18 
                 18 
                 18 
               
               
                 resistance value 
               
               
                   
               
             
          
         
       
     
         [0058]    As shown in Tables 8 to 10, when the OLEDs that are designed with the display region A 10  having a diagonal length equal to or greater than 101.6 mm but less than 177.8 mm have a bezel with a minimum thickness satisfying Inequality 2, the mean drop impact resistance values thereof are 18, which means that the impact strength is excellent. 
         [0059]    Meanwhile, as the thickness of the bezel  40  increases, an overall thickness of the OLED display  100  increases. This makes it difficult to make the OLED display slim. An allowable maximum thickness of the bezel  40  for a slim mobile device (e.g., a personal multimedia player (PMP)) in accordance with variation of the diagonal length of the display region is shown in the following Table 12: 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
                 TABLE 12 
               
               
                   
                   
               
               
                   
                 Diagonal Length of Display 
                 Allowable Maximum Thickness 
               
               
                   
                 Region (mm) 
                 of Bezel (mm) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 101.6 
                 3 
               
               
                   
                 127 
                 4 
               
               
                   
                 152.4 
                 5 
               
               
                   
                   
               
             
          
         
       
     
         [0060]    Optimal thickness ranges of the bezels having various display region diagonal lengths can be represented as shown in the following Table 13 in accordance with Inequality 2 and results of Table 12: 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
                 TABLE 13 
               
               
                   
                   
               
               
                   
                 Diagonal Length of Display 
                 Optimal Thickness 
               
               
                   
                 Region (mm) 
                 of Bezel (mm) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 101.6 
                 1.19~3 
               
               
                   
                 127 
                 1.86~4 
               
               
                   
                 152.4 
                 2.67~5 
               
               
                   
                   
               
             
          
         
       
     
         [0061]    Next, when the OLED display  100  is designed with the display region A 10  having a diagonal length d equal to or greater than 177.8 mm (7 inches), the bezel  40  is designed to satisfy the following inequality 3. 
         [0000]        t≧ 0.00015 ×a   [Inequality 3] 
         [0000]    where, t(mm) is the thickness of the bezel  40  and a(mm 2 ) is the area of the display region A 10 . The thickness t of the bezel  40 , which is obtained by Inequality 3, is a minimum thickness of the bezel  40  that can secure a desirable drop impact resistance property. 
         [0062]    A test for determining damage of the panel assembly  20  was performed by allowing the drop jig of  FIG. 5  with the OLED display  100  arranged within, which is designed with the display region A 10  having the diagonal length d equal to or greater than 177.8 mm, to execute a free-fall from a height of 75 cm. Except for the change in drop height, the drop impact resistance test was identical to that performed for tables 9 through 11 above. 
         [0063]    First, an OLED display that is designed with a display region having a diagonal length of 177.8 mm (7 inches) and an area of 15174.16 mm 2  will be described. In this case, a minimum thickness of the bezel according to Inequality 3 is 2.27 mm. Drop impact resistance test results for bezels having various thicknesses are shown in the following Table 14: 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 14 
               
               
                   
                   
               
               
                   
                 Comparative Examples 
                 Examples 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Thickness of bezel 
                 2.07 
                 2.17 
                 2.27 
                 2.37 
                 2.47 
                 2.57 
               
               
                 (mm) 
               
               
                 Mean drop impact 
                 14 
                 17 
                 18 
                 18 
                 18 
                 18 
               
               
                 resistance value 
               
               
                   
               
             
          
         
       
     
         [0064]    Next, an OLED display that is designed with a display region having a diagonal length of 203.2 mm (8 inches) and an area of 19819.32 mm 2  will be described. In this case, a minimum thickness of the bezel according to Inequality 3 is 2.97 mm. Drop impact resistance test results for bezels having various thicknesses are shown in the following Table 15: 
         [0000]    
       
         
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                 TABLE 15 
               
               
                   
                   
               
               
                   
                 Comparative Examples 
                 Examples 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Thickness of bezel 
                 2.77 
                 2.87 
                 2.97 
                 3.07 
                 3.17 
                 3.27 
               
               
                 (mm) 
               
               
                 Mean drop impact 
                 14 
                 16 
                 18 
                 18 
                 18 
                 18 
               
               
                 resistance value 
               
               
                   
               
             
          
         
       
     
         [0065]    As shown in Tables 14 and 15, when the OLEDs are designed with the display region A 10  having a diagonal length equal to or greater than 177.8 mm have a bezel with a minimum thickness satisfying Inequality 3, the mean drop impact resistance values thereof are 18, which means that the impact strength is excellent. 
         [0066]    Meanwhile, as the thickness of the bezel  40  increases, an overall thickness of the OLED display  100  increases. This makes it difficult to making the OLED display slim. An allowable maximum thickness of the bezel  40  for a wall-mountable display device in accordance with variation of the diagonal length of the display region is shown in the following Table 16: 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 16 
               
               
                   
                   
               
               
                   
                 Diagonal Length of Display 
                 Allowable Maximum Thickness 
               
               
                   
                 Region (mm) 
                 of Bezel (mm) 
               
               
                   
                   
               
             
             
               
                   
                 177.8 
                 5 
               
               
                   
                 203.2 
                 6 
               
               
                   
                   
               
             
          
         
       
     
         [0067]    Optimal thickness ranges of the bezels having various display region diagonal lengths can be represented as shown in the following Table 17 in accordance with Inequality 3 and results of Table 16: 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 17 
               
               
                   
                   
               
               
                   
                 Diagonal Length of Display 
                 Optimal Thickness 
               
               
                   
                 Region (mm) 
                 of Bezel (mm) 
               
               
                   
                   
               
             
             
               
                   
                 177.8 
                 2.27~5 
               
               
                   
                 203.2 
                 2.97~6 
               
               
                   
                   
               
             
          
         
       
     
         [0068]    According to the present exemplary embodiment, since the bezel  40  of the OLED display  100  is made out of synthetic resin and the thickness of the bezel  40  increases in proportion to the area of the display region A 10 , the reliability of the drop impact resistance can be securely maintained even when the OLED display is designed to have a relatively large display size. 
         [0069]    While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.