Abstract:
An LCD including an LCD panel and a frame having a front frame portion providing a display window exposing a display area of the LCD panel. The frame includes a side frame portion and a chamfer portion intermediate the front and side frame portions.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of priority from Korean Patent Application No. 2005-0050439, filed on Jun. 13, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a liquid crystal display, and more particularly, to a liquid crystal display having increased protection from damage resulting from an external physical impact. 
   2. Description of the Related Art 
   In general, a liquid crystal display (“LCD”) is a device for displaying an image, using pixels including liquid crystal cells aligned in a matrix form. The light transmittance of the pixel cells is adjusted in response to an image signal. The LCD forms an image on an LCD panel typically through the use of light from a backlight unit. 
   The LCD comprises an LCD panel on which liquid crystal cells formed in pixel units which are aligned in a matrix. Additionally, driving circuitry is provided for the liquid crystal cells, along with a backlight unit which uniformly provides light to the LCD panel. A container is provided for the above and a support member which exposes a display area cooperates with the container. The frame typically comprises a front frame portion which is disposed along the edge of the LCD panel so that the display area is exposed. A side frame portion extends from the front frame portion to the lateral side of the LCD panel. The support member protects the LCD from external impact and stably supports the LCD panel. 
   As the LCD becomes larger, slimmer and lighter, fewer attachment components such as screws are used to decrease fabrication time, thus enhancing productivity and reducing manufacturing costs. 
   However, if fewer attachment components are used, the support member will not stably support the components of the LCD and adequately protect the components inside the LCD from damage resulting from external impacts. More particularly, as the LCD becomes larger, slimmer and lighter, the support member is more easily bent by external impacts, and the LCD is not adequately protected. 
   SUMMARY OF THE INVENTION 
   Accordingly, it is an aspect of the present invention to provide a liquid crystal display having increased resistance to damage from external impacts. 
   The foregoing and other aspects of the present invention are achieved by providing an LCD comprising an LCD panel; and a support structure for the LCD panel, the support structure comprising: an LCD panel; and a support structure for the LCD panel, the support structure comprising: a frame extending around a perimeter of the LCD panel, the frame having a display window exposing a display area of the LCD panel, wherein the frame comprises a front frame portion positioned in a first plane, a side frame portion positioned in a second plane and a chamfer portion positioned in a third plane and being positioned intermediate the front and side frame portions. 
   According to the embodiment of the present invention, a ratio of a width of the chamfer portion to a length of a side of the LCD panel is in a range of 0.002 to 0.01. 
   According to the embodiment of the present invention, the width of the chamfer is in a range of 2 mm to 6 mm. 
   According to the embodiment of the present invention, an angle between the front frame and the chamfer is in a range of 120 degrees to 150 degrees. 
   According to the embodiment of the present invention, the fixing member is made of an alloy of aluminum. 
   According to the embodiment of the present invention, the LCD further comprises an accommodating container accommodating a backlight unit, wherein the fixing member is combined with the accommodating container. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of the exemplary embodiments, taken in conjunction with the accompanying drawings of which: 
       FIG. 1  is an exploded perspective view of an LCD according to an embodiment of the present invention; 
       FIG. 2  is a sectional view taken along line  2 - 2  of  FIG. 1 ; 
       FIG. 3  is a graph showing deformation in millimeters as a function of time of a conventional frame and a frame according to the present invention; and 
       FIG. 4  is a graph showing stress of a conventional LCD panel and an LCD panel according to the present invention against the external impact as a function of time. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures. 
   In an embodiment, a direct type will be described as an example of a backlight unit. 
     FIG. 1  is an exploded perspective view of an LCD and  FIG. 2  is a sectional view of the LCD according to the embodiment of the present invention. 
   LCD  1  is comprised of an LCD panel  20  on which an image is formed, a gate driving part  30  and a data driving part  35  which drive the LCD panel  20 , a backlight unit  90  which radiates light to a rear of the LCD panel  20 , a container  100  which supports and encloses the backlight unit  90 , and frame  10 , which cooperates with container  100 , to cover the front surface of the LCD panel  20 . 
   The LCD panel  20  comprises a Thin Film Transistor (TFT) substrate  21 , a color filter substrate  22  disposed face to the TFT substrate  21  and a liquid crystal (not shown) interposed between the two substrates. Also, the LCD panel  20  further comprises polarizers  23  and  24  respectively which are adhered on a front surface of the color filter substrate  22  and on a rear surface of the TFT substrate  21  so that light passing through the LCD panel  20  is cross polarized. On the LCD panel  20 , there are aligned liquid crystal cells formed in a pixel unit and aligned in a matrix form. The liquid crystal cells form an image by adjusting the light transmittance through the liquid crystal cells according to an image signal transmitted from the driving part  30  and  35 . 
   A plurality of gate lines and a plurality of data lines are formed on the TFT substrate  21  in a matrix form and a TFT is formed at the intersection of the gate lines and the data lines. A signal voltage transmitted from the driving part  30  and  35  is applied between a pixel electrode and a common electrode of the color filter substrate  22  through the TFT. Under the control of the TFT, the liquid crystal between the pixel electrode and the common electrode is aligned by the signal voltage, thereby determining light transmittance. 
   The color filter substrate  22  comprises a color filter on which a red, a green and a blue or a cyan, a magenta and a yellow color filters are repeatedly formed on the boundary of a black matrix and a common electrode. The common electrode is typically comprised of transparent conductive substance such as ITO (Indium Tin Oxide), or IZO (Indium Zinc Oxide). The color filter substrate  22  has a smaller area than the TFT substrate  21 . 
   The gate driving part  30  comprises a gate driving chip  31  to apply a gate driving signal and an Flexible Printed Circuit (FPC)  33  on which the gate driving chip  31  is mounted using a COF (Chip On Film) method. On the FPC, there are disposed the gate driving chip  31  and a circuit pattern connected to a gate pad, which is an end part of the gate line of the TFT substrate  21 . The gate driving part  30  extends to the lateral side of the LCD panel  20  while being bent at approximately 90 degrees due to assembling the frame  10 . The gate driving part  30  applies the gate driving signal comprised of a gate-on voltage (Von) and a gate-off voltage (Voff) from a driving circuit part  40  connected to the data driving part  35  respectively to the gate lines. 
   The data driving part  35  comprises a data driving chip  36  to apply a data driving signal and an FPC  37  on which the data driving chip  36  is mounted using a COF method and of which one side is connected to an end of the data line on the TFT substrate  21 . Another side of the FPC  37  is connected to the driving circuit part  40  controlling the gate driving chip  31  and the data driving chip  36 . The data driving part  35  extends to the lateral side of the LCD panel  20  and the driving circuit part  40  is disposed in rear of the accommodating container  100 . The data driving part  35  is provided with a Gray scale voltage from a Gray scale voltage generator (not shown), which selects the Gray scale voltage based on a signal from the signal controller, and then applies the data driving signal to the data line. 
   The liquid crystal disposed between the TFT substrate  21  and the color filter substrate  22  is applied with the gate driving signal and the data driving signal from the gate driving part  30  and the data driving part  35  and is realigned accordingly. 
   The backlight unit  90  which is disposed in rear of the LCD panel  20  comprises optical sheet assembly  50 , a lamp unit  60  and a reflective sheet  80 . 
   The optical sheet assembly  50  comprises a protection sheet  51  disposed in rear of the LCD panel  20 , a prism sheet  53  and a diffusion sheet  55 . The diffusion sheet  55  is comprised of a base plate and a coating layer having beads formed on the base plate. The diffusion sheet  55  diffuses light from the lamp  61  to provide it to the LCD panel  20 . Two or more overlapping sheets like diffusion sheet  55  may be used. Prism sheet  53  includes a plurality of triangularly-shaped prisms at a predetermined alignment. The prism sheet  53  concentrates light diffused from the diffusion sheet  55  in a direction which is perpendicular to the plane of the surface of the LCD panel  20 . Typically, the prism sheet  53  consists of two sheets each of which includes micro prisms formed on the each prism sheet, with the prisms being positioned at a predetermined angle with each other. The light passing through the prism sheet  53  progresses vertically to provide a uniform brightness to the LCD panel. The protection sheet  51 , disposed on the top, protects the prism sheet  53  which is vulnerable to scratching. 
   The lamp unit  60  is comprised of a lamp portion  61  which radiates light, a lamp electrode (not shown) formed at the end of the lamp  61  and a lamp holder  63  in which the end of the lamp  61  is inserted. The lamp unit  60  is driven by being supplied with electric power from an inverter (not shown). A plurality of lamp units  60  are disposed in parallel over the entire rear of the LCD panel  20 . A plurality of lamps  61  are inserted in the lamp holder  63  in a pair. The lamp holder  63  supports the lamp  61  and is accommodated in a side mold  70 . 
   In the embodiment of the present invention, a Cold Cathode Fluorescent Lamp (CCFL) is used as a light source. Alternatively, External Electrode Fluorescent Lamp (EEFL) may be used. EEFLs provide a brighter light, cost less and consume less power than CCFLs, and is capable of driving a plurality of lamp units  60  with one inverter (not shown). 
   Referring to  FIGS. 1 and 2 , it will be appreciated that side support  70  is stair-shaped and hollow. First and second side supports  70  are disposed at opposite lateral sides of the container  100 . Side support  70  includes a groove  71  in which the lamp holder  63  is inserted when the lamp  61  is combined with the groove  71 . A first stair of the side support  70  supports an edge of the optical sheets  50  and the second stair of the side support  70  supports the edge of the LCD panel  20 . Thus, LCD panel  20  is spaced apart from the lamp units  60  by the side support  70 . 
   The reflective sheet  80 , disposed between the lamp  61  and the container  100 , reflects light from the lamp  61  and directs it toward diffusion sheet  55 . The reflective sheet  80  is made of PET (Polyethylene terephthalate) or PC (Polycarbonate). 
   Frame  10  is comprised of a front frame portion  12  which terminates in lip  11  which exposes a display area of the LCD panel  20 . Side frame portion  14  extends downwardly from chamfer portion  13  which extends from front frame portion  12 . Thus, frame  10  includes the chamfer portion  13  which is bent from the front frame portion  12  at a predetermined slant angle indicated by the Greek letter θ and shown in  FIG. 2 . Side frame portion  14  extends from the chamfer portion  13  to the lateral side of the LCD panel  20  and side frame portion  14  cooperates with the container  100 . The front frame portion  12  is disposed along the edge of the LCD panel  20  so that the display area of the LCD panel  20  is exposed to the outside and the side frame  14  cooperates with the upwardly extending wall  110  of container  100 . Frame  10  may be constructed of aluminum. 
   As shown in  FIG. 2 , and indicated by angle θ, chamfer  13  slants at approximately 120˜150 degrees from the front frame  12 . The ratio between the width d 1  of the chamfer portion  13  and the longer side of the LCD panel  20  should preferably be maintained in a range of 0.002 to 0.01. Providing chamfer  13  along with front frame portion  12  and side frame portion  14  serves to protect the components inside the LCD  1  from the external impact without interfering with the components. 
   The container  100  encloses and supports the backlight unit  90  and is combined with the frame member  10 . 
     FIGS. 3 and 4  are simulated graphs showing deformation of the frame  10  and stress on the LCD panel  20  resulting from an impact in comparison to a conventional LCD without the chamfer, and an LCD with the 4 mm-wide chamfer. A 40-inch TV was used in the simulation. 
   The frame  10  may be viewed as a plurality of integrated plates of different sizes. Resistance of each plate to external impact, which specially resists bending, is expressed as second moment of an area, that is inertial moment. 
   The second moment of an area is a value showing that the resistance to bending according to a shape of cross section varies despite the same material and the same cross section area. The larger the second moment of an area is, the higher the resistance to bending, therefore the plates with high resistance may be more stable material. 
   The first moment of an area is a force generated when material having a micro area is pressurized and is expressed as (distance from standard axis)*(area of cross section).
 
Gx=∫ydA
 
   Further, the second moment of area (or moment of inertia) is expressed as (distance from standard axis)^2* (area of cross section), and the value corresponds to the sum of values of the first moment of an area.
 
Ix=∫y 2 dA
 
   With regard to the cross section of a member operated on by an external impact, the stress is proportional to a distance from an axis of the center of gravity. Therefore the stress, a force generated in material when a strength is given the material, is expressed as follows. 
   
     
       
         
           Stress 
           = 
           
             
               Action 
               ⁢ 
               
                   
               
               ⁢ 
               moment 
               * 
               Distance 
             
             
               Second 
               ⁢ 
               
                   
               
               ⁢ 
               moment 
               ⁢ 
               
                   
               
               ⁢ 
               of 
               ⁢ 
               
                   
               
               ⁢ 
               area 
             
           
         
       
     
   
   Accordingly, if the second moment of the area is large, which makes the stress low, thereby showing that the resistance of the material against the external impact is high and flexural rigidity and stability of the material is high, as well. 
   In the aforementioned respect, when a force of 50 times that of gravity is applied to a frame of a 40-inch LCD for 11 seconds, the deformation of the frame and the stress to the LCD panel  20  in a conventional LCD without a chamfer and the LCD  100  with chamfer  13  having a dimension d 1  of 4 mm the comparison thereof is described below. 
   As shown in  FIG. 3 , the deformation of a conventional frame without a chamfer such as  13  of frame  10 , is larger than the deformation of the frame  10  which includes the chamfer  13 . Numerically, the maximum deformation of frame  10  with the chamfer  13  is reduced about 28.2% as compared with the maximum deformation of a conventional frame. This illustrates the improved resistance and the flexural strength of frame  10  with the chamfer  13  against the external impact increase. 
   As shown in  FIG. 4 , the stress on a conventional LCD panel without a chamfer is larger over time than the stress on the LCD panel  20  with the chamfer  13 . Numerically, the maximum stress on LCD panel  20  with the chamfer  13  is reduced about 62% as compared with the maximum stress on a conventional LCD panel without a chamfer. This shows that frame  10  with the chamfer  13  efficiently protects and supports components inside the LCD  1  from external impacts. 
   For a 40-inch, diagonally measured, LCD  1 , a width d 1  of the chamfer  13  is preferably 2 mm˜6 mm. If the chamfer  13  is 2 mm or less in the width, there is no difference when the chamfer  13  does not exist. It has been observed that when chamfer  13  is 6 mm in the width, frame  10  efficiently protects and supports the components, but does not interfere with the components. 
   The deformation of a conventional frame and frame  10  when the force corresponding to 50 times of gravity is applied to frame  10  for 11 seconds, is: (i) conventional if the chamfer  13  does not exist and (ii) frame  10  with the chamfer  13  of 2 mm and (iii) frame  10  with the chamfer of 4 mm in the width, respectively. The deformation of the fixing member  10  is as follows: (i) 3 mm for frame without a chamfer; (ii) 2.5 mm when member  10  has a 2 mm-width chamfer  13 ; and (iii) 2.18 mm when frame  10  has a 4 mm-width chamfer  13 . Numerically, the deformation of frame  10  with the 2 mm-width chamfer  13  is decreased about 17% as compared with the deformation of a conventional frame without a chamfer; and the deformation of frame  10  with the 4 mm-width chamfer  13  is decreased about 27% as compared with the deformation of a conventional frame without a chamfer. Likewise, it is preferable that the width d 1  of the chamfer  13  is wide enough not to interfere with the components inside the LCD  1 . 
   Although a few embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.