Patent Publication Number: US-8125587-B2

Title: Liquid crystal display module and assembling method thereof

Description:
The present patent document is a divisional of U.S. patent application Ser. No. 12/265,856, filed Nov. 6, 2008 now U.S. Pat. No. 7,929,075, which claims priority to Korean Patent Application No. P2007-115240 filed in Korea on Nov. 13, 2007, which is hereby incorporated by reference. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates to a liquid crystal display module, and more particularly, to a liquid crystal display module and an assembling method thereof which are capable of simplifying an assembling process for the liquid crystal display module while preventing foreign substance from entering the interior of the liquid crystal display module upon fastening screws to the liquid crystal display module. 
     2. Discussion of the Related Art 
     With the progress of an information-dependent society, the demand for various display devices has increased. To meet such a demand, efforts have recently been made to research flat panel display devices such as liquid crystal display (LCD) devices, plasma display panels (PDPs), electro-luminescent display (ELD) devices, vacuum fluorescent display (VFD) devices, and the like. Some types of such flat panel display devices are being practically applied to various appliances for display purposes. 
     In particular, LCDs have been used as a substitute for cathode ray tubes (CRTs) in association with mobile image display devices because LCDs have advantages of superior picture quality, lightness, thinness, and low power consumption. Thus, LCDs are currently most widely used. Various applications of LCDs are being developed in association with not only mobile image display devices such as monitors of notebook computers, but also monitors of TVs to receive and display broadcasting signals, and monitors of laptop computers. 
     Generally, an LCD device includes a liquid crystal display module or LCM, and a driving circuit for driving the liquid crystal display module. 
     The liquid crystal display module includes a liquid crystal panel, and a backlight unit for irradiating light to the liquid crystal panel. The liquid crystal display module also includes top and bottom cases defining a space for receiving the backlight unit and liquid crystal panel. 
     The liquid crystal display module further includes a panel guide enclosing respective edges and respective side surfaces of a diffusion plate and a plurality of optical sheets, which are included in the backlight unit, and a support side member enclosing opposite ends of lamps included in the backlight unit. The panel guide and support side member are fastened to the bottom case by screws. 
     In detail, the support side member is fastened to the bottom case, and the panel guide is then fastened to both the bottom case and the support side member fastened to the bottom case. In this case, accordingly, a fastening process needs to be carried out twice. In the fastening process, insert nuts are also used. This increases the cost. Furthermore, a metallic foreign substance, which may be formed during the screw-fastening process, may enter the interior of the liquid crystal display module. The metallic foreign substance may generate an electrical short circuit with a printed circuit board mounted in the liquid crystal display module. 
     BRIEF SUMMARY 
     A liquid crystal display module comprises: a panel guide for supporting a liquid crystal panel, the panel guide including a first fastening portion; support side members for holding opposite sides of a lamp irradiating light to the liquid crystal panel, respectively, each of the support side members including a second fastening portion having a foreign substance shield; and a bottom case including a third fastening portion having a case hole formed through a side surface of the bottom case, to receive the foreign substance shield. 
     In another aspect of the present invention, a method for assembling a liquid crystal module comprises: preparing a panel guide for supporting a liquid crystal panel, the panel guide including a first fastening portion, support side members for holding opposite sides of a lamp irradiating light to the liquid crystal panel, respectively, each of the support side members including a second fastening portion having a foreign substance shield, and a bottom case including a third fastening portion having a case hole formed through a side surface of the bottom case, to receive the foreign substance shield; aligning the panel guide, the support side members, and the bottom case such that the first to third fastening portions overlap; and fastening the first to third fastening portions by screws, and inserting the foreign substance shield into the case hole. 
     With the disclosed structure and method, the assembling process can be simplified because the panel guide, support side members, and bottom case are fastened at one time by screws or the like. Also, it is possible to prevent metallic foreign substance formed during the fastening of the screws from entering the interior of the liquid crystal display module, and thus to prevent printed circuit boards from being short-circuited by metallic foreign substance because the foreign substance shield is fitted in the case hole of the bottom case. 
     It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and along with the description serve to explain the principle of the invention. In the drawings: 
         FIG. 1  is an exploded perspective view schematically illustrating a liquid crystal display (LCD) device according to an exemplary embodiment of the present invention, which includes a backlight unit; 
         FIG. 2  is an exploded perspective view for explaining a fastening process for a panel guide, support side members, and a bottom case; and 
         FIG. 3  is a cross-sectional view taken along the line I-I in  FIG. 2 , illustrating the fastened panel guide, support side members, and bottom case. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS AND THE PRESENTLY PREFERRED EMBODIMENTS 
     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     Hereinafter, a liquid crystal display module and an assembling method thereof according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings. 
       FIG. 1  is an exploded perspective view schematically illustrating a liquid crystal display (LCD) device according to an exemplary embodiment of the present invention, which includes a backlight unit. 
     The LCD device shown in  FIG. 1  includes a liquid crystal panel  100  for displaying an image, and a backlight unit  2  for supplying light to the liquid crystal panel  100 . The LCD device also includes a top case  130  and a bottom case  10 , which receive the liquid crystal panel  100  and backlight unit  2 . 
     The top case  130  has a bent structure to enclose a non-display area of the liquid crystal panel  100  and side surfaces of the bottom case  10 . The top case  130  is fastened to a panel guide  90 , which encloses the side surfaces of the bottom case  10 . 
     The liquid crystal panel  100  is seated on the panel guide  90 . The liquid crystal panel  100  controls the transmittance of light supplied from the backlight unit  2  in accordance with an input image signal, to display an image. The liquid crystal panel  100  includes a lower substrate  102 , an upper substrate  104 , a liquid crystal layer (not shown) formed between the lower substrate  102  and the upper substrate  104 , and spacers (not shown) for maintaining a certain spacing between the lower substrate  102  and the upper substrate  104 . 
     The upper substrate  104  includes color filters, a black matrix, and common electrodes. 
     The lower substrate  102  includes thin film transistors, and pixel electrodes respectively connected to the thin film transistors. The common electrodes, which are provided at the upper substrate in the illustrated case, may be formed at the lower substrate  102  in accordance with a liquid crystal mode different from that of the illustrated case. 
     Formed on the non-display area of the lower substrate  102  are data pad areas respectively connected to data lines (not shown) and gate pad areas respectively connected to gate lines (not shown). A plurality of data circuit films  110 , on which data integrated circuits  112  are mounted to supply image signals to the data lines, are attached to the data pad areas, respectively. A plurality of gate circuit films  120 , on which gate integrated circuits  122  are mounted to supply gate scan signals to the gate lines, are attached to the gate pad areas, respectively. 
     Otherwise, the data integrated circuits  112  and gate integrated circuits  122  may be directly mounted on the lower substrate  102  in accordance with a chip-on-glass (COG) method, or may be formed together with the thin film transistors of the lower substrate  102  such that they are built in the lower substrate  102 . 
     The backlight unit  2  includes a plurality of lamps  40  each having first and second electrodes  42  and  44 , a first socket unit including a plurality of first sockets  22  connected to respective first electrodes  42  of the lamps  40 , and a second socket unit including a plurality of second sockets  32  connected to respective second electrodes  44  of the lamps  40 . The backlight unit  2  also includes a diffusion plate  70  arranged beneath the panel guide  90  such that the diffusion plate  70  faces the lamps  40 , at least one optical sheet  80  arranged on the diffusion plate  70 , a first support side member  50  arranged at one side of the bottom case  10 , to enclose the first socket unit and one end of each lamp  40 , and a second support side member  60  arranged at the other side of the bottom case  10 , to enclose the second socket unit and the other end of each lamp  40 . 
     The diffusion plate  70  diffuses light irradiated from the lamps  40  over the entire region of the liquid crystal panel  100 . 
     The optical sheet  80  functions to cause the light diffused by the diffusion plate  70  to be vertically irradiated to the liquid crystal panel  100 . To this end, the optical sheet  80  may include at least one prism sheet for condensing the light diffused by the diffusion plate  70 . In the illustrated case, the optical sheet  80  includes two prism sheets  82  and  84 . 
     The first and second socket units are arranged on first and second printed circuit boards (PCBs)  20  and  30 , respectively. Each of the PCBs  20  and  30  is provided with a common line to supply a lamp driving voltage. 
     The lamps  40  are separably mounted between the sockets  22  and  32  respectively mounted on the first and second PCBs  20  and  30  such that the lamps  40  face the liquid crystal panel  100 . Each lamp  40  may be a cold cathode fluorescent lamp (CCFL). Each lamp  40  is turned on by a lamp driving voltage supplied from the associated sockets  22  and  32 , to irradiate light to the liquid crystal panel  100 . 
     Although not shown, a lamp tube, in which phosphors emit light in accordance with gas discharge, or an external electrode fluorescent lamp (EEFL), in which electrodes are arranged on an outer surface of a lamp tube body at opposite ends of the lamp tube body, may be used for each lamp  40 . In this case, the structure of each socket may be changed. 
     The panel guide  90  is mounted on a seat portion of the bottom case  10  such that the panel guide  90  can enclose not only the edges and side surfaces of the diffusion plate  70  and optical sheets  80 , but also the side surfaces of the bottom case  10 . The panel guide  90  also functions to support the liquid crystal panel  100 , to prevent the backlight unit  2  from moving, and to absorb external impact applied to the backlight unit  2 . 
     The bottom case  10  is manufactured to have a bottom surface facing the lamps  40 , and inclined surfaces upwardly inclined from the bottom surface by a certain inclination. A reflection sheet  12  is attached to the bottom surface and inclined surfaces of the bottom case  10 , in order to reflect light irradiated from each lamp  40  toward the liquid crystal panel  100 . Alternatively, a reflective material may be coated over the bottom surface and inclined surfaces of the bottom case  10 . 
       FIG. 2  is an exploded perspective view for explaining a fastening process for the panel guide  90 , support side members  50  and  60 , and bottom case  10 . 
     As shown in  FIG. 2 , the panel guide  90  includes at least one first fastening portion  140  formed on at least one side surface of the panel guide  90 , in order to enable the panel guide  90  to be fastened with the support side members  50  and  60 , and bottom case  10 . The first fastening portion  140  has a first fastening surface  140   a  recessed from the upper surface of the panel guide  90  in a stepped state, and a first fastening hole  140   b  formed through the first fastening surface  140   a.    
     Each of the support side members  50  and  60  includes a second fastening portion  150 , which will be fastened to the first fastening portion  140 . The second fastening portion  150  has a second fastening surface  150   a  protruded from the surface of the associated support side member  50  or  60  in a stepped state such that the second fastening surface  150   a  corresponds to the first fastening surface  140   a , a second fastening hole  150   b  formed through the second fastening surface  150   a  such that the second fastening hole  150   b  corresponds to the first fastening hole  140   b , and a foreign substance shield  150   c  extending inclinedly from the second fastening surface  150   a  toward the bottom case  10 , to prevent foreign substance from entering the interior of the liquid crystal display module. One end  15   a  of the foreign substance shield  150   c  is arranged to be nearer to a light emitting region of the lamps  40  than the second fastening hole  150   b . The other end  15   b  of the foreign substance shield  150   c  is inserted into a case hole  160   c  provided at the bottom case  10 . 
     The bottom case  10  includes a third fastening portion  160  formed on at least one side surface of the bottom case  10 , in order to enable the bottom case  10  to be fastened with the first and second fastening portions  140  and  150 . The third fastening portion  160  has a third fastening surface  160   a  extending from one surface of the bottom case  10  to the interior of the liquid crystal display module in a bent state such that the third fastening surface  160   a  corresponds to the first and second fastening surfaces  140   a  and  150   a , and a third fastening hole  160   b  formed through the third fastening surface  160   a  such that the third fastening hole  160   b  corresponds to the first and second fastening holes  140   b  and  150   b . The case hole  160   c  is also included in the third fastening portion  160 . The case hole  160   c  is formed through one side surface of the bottom case  10  such that the foreign substance shield  150   c  can be inserted into the case hole  160   c.    
     The fastening portions  140  and  160  of the panel guide  90  and bottom case  10  may be formed at four side surfaces, in order to obtain a maximum fastening force. 
     The corresponding first to third fastening holes  140   b ,  150   b , and  160   b  are fastened at one time by a screw  200  or the like, as shown in  FIG. 3 . At the same time, the other end  15   b  of the foreign substance shield  150   c  is inserted into the case hole  160   c  of the bottom case  10 . 
     Thus, the assembling process can be simplified because the panel guide  90 , support side members  50  and  60 , and bottom case  10  are fastened at one time by a screw or the like, as described above. Also, it is possible to prevent metallic foreign substance formed during the fastening of the screw  200  from entering the interior of the liquid crystal display module, because the foreign substance shield  150   c  is fitted in the case hole  160   c  of the bottom case  10 . Since the fastening of the screw  200  is achieved through the fastening holes  140   b ,  150   b , and  160   b , it is unnecessary to additionally use an insert net for the fastening of the screw  200 , as compared to related art&#39;s cases. Accordingly, a reduction in material costs is achieved. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.