Abstract:
A liquid crystal display (LCD) device and portable display device are disclosed. The LCD device includes an LCD panel; a top case covering a periphery of the LCD panel; and a connection member between the LCD panel and the top case to provide an electrical contact between the LCD panel and the top case.

Description:
[0001]     This application claims the benefit of the Korean Patent Application No. P2004-91300, filed on Nov. 10, 2004, which is hereby incorporated by reference as if fully set forth herein.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a display device and portable display device, and more particularly, to a liquid crystal display (LCD) device having a spring or other compressing means to electrically ground the display panel without using a separate conductive tape.  
         [0004]     2. Discussion of the Related Art  
         [0005]     Generally, a liquid crystal display device includes a liquid crystal display module, a drive circuit unit for driving the liquid crystal display module, and a case. The liquid crystal display (LCD) module includes an LCD panel and a backlight unit for applying light to the LCD panel. The LCD panel includes a plurality of liquid crystal cells arranged in a matrix form in a pair of glass substrates between which liquid crystal is provided and switching devices for switching signals supplied to the liquid crystal cells. Moreover, optical sheets are arranged on the LCD module to direct the light emitted from the backlight unit toward the LCD panel.  
         [0006]     The LCD panel, backlight unit and optical sheets are joined in one body to prevent a light loss and to be protected against external shocks. For this end, a top case is provided to enclose an edge of the LCD panel, the backlight unit and the optical sheets.  
         [0007]     The drive circuit unit is mounted on a printed circuit board (hereinafter abbreviated as PCB) to drive the LCD panel. A tape carrier package (hereinafter abbreviated as TCP) is generally used to connect the LCD panel with the PCB for signal transfer. The TCP is directly attached to the lower substrate of the LCD panel and the PCB using a conductive resin. The TCP includes a flexible layer of polyimide and the like and a metal-based conductive layer embedded in the flexible layer to form a mono- or multi-layer structure.  
         [0008]     As described above, the LCD module including a glass substrate is vulnerable to external shocks. To protect the LCD panel from the external shocks, the top case is used to enclose an exterior of the LCD module.  
         [0009]     A liquid crystal display (LCD) device according to the related art will now be described with reference to the accompanying drawings.  FIG. 1  illustrates a layout of an LCD device according to the related art and  FIG. 2  is a cross-sectional view taken along the cutting line I-I′ in  FIG. 1 .  
         [0010]     Referring to  FIG. 1  and  FIG. 2 , an LCD device according to the related art includes a reflector  42 , a light guide plate  44 , a plurality of optical sheets  46  stacked on the light guide plate  44 , an LCD panel  48  having a pair of substrates facing each other and first and second polarizing plates  40   a  and  40   b  provided on the backsides of the substrates, a plastic main support  34 , and a top case and bottom cover  32  and  36  enclosing the main support  34  and an edge of the LCD panel  48 .  
         [0011]     The LCD device uses a Cu- or Al-sided conductive tape  38 . A conductive metal is formed on one surface of the conductive tape  38  and an adhesive substance is coated on the other surface of the conductive tape  38 . When the adhesive portion of the conductive tape  38  is attached to the top case  32 , the metal surface of the conductive tape  38  contacts a upper glass substrate of the LCD panel  48 , the main support  34  and the bottom cover  36 . The conductive tape  38  discharges static electricity generated from the LCD panel  48  to the bottom cover  36 .  
         [0012]     However, the LCD device according to the related art has the following problems. First of all, adhesion failure of the conductive tape occurs due to mass production of the LCD devices. The conductive tape is attached to a narrow area of the LCD panel and exposed to an environment of high temperature and vibration during the fabrication process of the LCD process. Thus, the adhesiveness of the conductive tape is weakened so that the conductive tape is easily detached from the LCD panel, which creates a grounding defect between the LCD panel and the bottom cover and stains on the LCD panel.  
       SUMMARY OF THE INVENTION  
       [0013]     Accordingly, the present invention is directed to a liquid crystal display device and portable display device that substantially obviate one or more problems due to limitations and disadvantages of the related art.  
         [0014]     An advantage of the present invention is to provide a liquid crystal display device and portable display device having a spring or other compressing means to electrically ground the display panel without using a separate conductive tape.  
         [0015]     Additional advantages and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. These and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.  
         [0016]     To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a liquid crystal display (LCD) device according to the present invention includes an LCD panel; a top case covering a periphery of the LCD panel; and a connection member between the LCD panel and the top case to provide an electrical contact between the LCD panel and the top case.  
         [0017]     In another aspect of the present invention, a liquid crystal display (LCD) device includes an LCD panel; a top case covering a periphery of the LCD panel; and a compressing means for grounding the LCD panel to the top case.  
         [0018]     In yet another aspect of the present invention, a liquid crystal display (LCD) device includes an LCD panel; a top case covering a periphery of the LCD panel; an insulating main support supporting the LCD panel; and a compressing member having an electric contact with at least one of the top case, the LCD panel and the insulating main support.  
         [0019]     In still another aspect of the present invention, a portable display device includes a display panel; a top case covering a periphery of the display panel; an insulating main support supporting the display panel; and an electrically conductive elastic member contacting the top case to ground the display panel to the top case.  
         [0020]     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  
       [0021]     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 together with the description serve to explain the principle of the invention.  
         [0022]     In the drawings:  
         [0023]      FIG. 1  illustrates a layout of an LCD device according to the related art;  
         [0024]      FIG. 2  is a cross-sectional view taken along the cutting line I-I′ in  FIG. 1 ;  
         [0025]      FIG. 3  is a perspective view illustrating a plate spring applied to an LCD device according to the present invention;  
         [0026]      FIG. 4  is a perspective view illustrating a top case to which the plate spring of  FIG. 3  is attached;  
         [0027]      FIG. 5  is a detailed view of a part B in  FIG. 4 ;  
         [0028]      FIG. 6  is a cross-sectional view taken along the cutting lines II-II′ in  FIG. 4  and  FIG. 5 ;  
         [0029]      FIG. 7A  and  FIG. 7B  are perspective views illustrating a plate spring attached to a top case in an LCD device;  
         [0030]      FIG. 8A  and  FIG. 8B  are perspective views illustrating a plate spring before and after assembling an LCD panel to a case top, respectively;  
         [0031]      FIG. 9  is a perspective view illustrating an LCD device according to another embodiment of the present invention and; and  
         [0032]      FIG. 10  is a cross-sectional view taken along the cutting line III-III′ in  FIG. 9 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0033]     Reference will now be made in detail to 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.  
         [0034]     FIGS.  3  to  8 B illustrate a liquid crystal display (LCD) device or portable display device (a display device small and light enough to be carried personally, for example, a laptop computer) according to an embodiment of the present invention.  FIG. 3  is a perspective view illustrating a plate spring applied to an LCD device according to the present invention,  FIG. 4  is a perspective view illustrating a top case to which the plate spring in  FIG. 3  is attached, and  FIG. 5  is a detailed view of a part B in  FIG. 4 .  FIG. 6  is a cross-sectional view taken along the cutting lines II-II′ in  FIG. 4  and  FIG. 5 .  FIG. 7A  and  FIG. 7B  are perspective views illustrating a plate spring attached to a top case in an LCD device and  FIG. 8A  and  FIG. 8B  are perspective views illustrating a plate spring before and after assembling an LCD panel to a case top.  
         [0035]     Referring to FIGS.  3  to  8 B, an LCD device according to the present invention includes an LCD panel  120  and a non-conductive main support  112  for supporting the LCD panel  120 . The LCD panel  120  includes first and second glass substrates  110   a  and  110   b  facing each other. First and second polarizing plates  109   a  and  109   b  are formed on surfaces (backsides) of the first and second glass substrates  110   a  and  110   b , respectively. A plurality of switching devices are formed on the second glass substrate  110   b  to switch signals supplied to liquid crystal cells. In addition, a color filter layer, a black matrix and/or a common electrode are, for example, formed on the first glass substrate  110   a.    
         [0036]     The LCD device further includes a backlight unit having a light guide plate  106 , a reflector  105 , and an optical sheet  107 . The light guide plate  106  guides the light generated from an area corresponding to the size of the LCD panel  120 . The reflector  105  is arranged under the light guide plate  106  and contacts the light guide plate  106 . The reflector  105  reflects the light from the light guide plate  106  toward the LCD panel  120 . As illustrated in  FIG. 6 , the reflector  105  is smaller than the light guide plate  106  so that end portions of the reflector  105  and light guide plate  106  do not coincide with each other. However, the reflector  105  can be larger than the light guide plate  106  according to another embodiment of the present invention, as illustrated  FIG. 10 .  
         [0037]     The optical sheet  107  is arranged between the light guide plate  106  and the LCD panel  120  and includes a plurality of individual sheets such as first and second prism sheets  107   a  and  107   b  neighboring to each other, a diffuser  107   c  and the like. The optical sheet  107  refracts the light from the light guide plate  106  toward the LCD panel  120 . The diffuser  107   c  spreads the light from the light guide plate  106  and the first and second prism sheets  107   a  and  107   b  uniformly disperse the light reaching the LCD panel  120  to improve the luminance of the LCD device in a viewing direction.  
         [0038]     The LCD panel  120 , the light guide plate  106  and the optical sheet  107  are joined together to minimize a light loss and protect the LCD device from external shocks. Because the LCD panel  120  includes the first and second glass substrates  110   a  and  110   b , which are fragile against the external shocks, the top case  104  encloses edges of the LCD panel, light guide and optical sheet  120 ,  106  and  107  to minimize a light loss and protect the LCD device from the external shocks. In particular, the top case  104  is secured to the main support  112  to enclose the edges of the LCD panel  120 .  
         [0039]     The main support  112  is, for example, formed of plastic and formed by a molding process. The main support  112  has at least one or more steps formed on its inner sidewall. The LCD panel  120  is placed on one of the steps. In the drawings, the second polarizing plate  109   b  contacts the main support  112 , but a periphery of the second glass substrate  110   b  may contact the main support  112  in another embodiment. Moreover, the main support  112  has at least one or more steps corresponding to the light guide plate  106  and the optical sheet  107 . Although not shown in  FIG. 6 , a lamp or other light source can be fitted in one of the steps of the main support, as illustrated in  FIG. 10 .  
         [0040]     The top case  104  encloses a periphery of the LCD panel  120  to be in contact with the bottom cover  111 . Each of the top case  104  and the bottom cover  111  is formed of a metal-based material such as stainless steel. The bottom cover  111  is secured to the main support  112  by screws or other means. The bottom cover  111  has a rectangular frame shape having a front portion and a side portion vertical to the front portion to cover the edges of the LCD panel  120 . The top case  104  does not directly contact the LCD panel  120  or the main support  112 .  
         [0041]     Referring to  FIG. 3  and  FIG. 5 , the plate spring  102  formed of an elastic conductive material is attached to a predetermined portion of the top case  104 . In particular, the plate spring  102  includes a first face  102   a  that is substantially flat and a second face  102   b  that has an arc shape. An end portion of the first face  102   a  is connected to the second face  102   b . The first face  102   a  is attached to a upper surface of the top case  104  via a two-sided conductive tape, soldering, a snap-fit, at least one screw or the like. The second face  102   b  contacts the main support  112  via a conductive tape, soldering or the like. Alternatively, the second face  102   b  may only contact the first glass substrate  110   a  without being attached to the main support  112 .  
         [0042]      FIG. 8A  and  FIG. 8B  illustrate the plate spring  102  before and after the LCD panel  120  is assembled to the top case  104 , in which other portions of the LCD device or the top case  104  are not shown.  
         [0043]     Referring to  FIG. 8A  and  FIG. 8B , an end portion of the first face has a ‘U’-shape in a side view. Before the plate spring  102  is attached to the top case  104 , an end portion of the second face  102   b  does not contact the U-shaped end portion of the first face  102   a . When the plate spring  102  is attached to the top case  104 , a middle portion of the second face  102   b  having an arc shape is pushed up so that the end portion of the second face  102   b  extends to and contacts the U-shaped end portion of the first shape  102   a.    
         [0044]     A positional relationship between the plate spring  102  and other parts is illustrated in  FIG. 7A  and  FIG. 7B , when the plate spring  102  is attached to the top case  104 . The top case  104  is omitted in  FIG. 7A  and  FIG. 7B . When the plate spring  102  is attached to the top case  104 , the backside of the second face  102   b  of the plate spring  102  contacts a periphery of the LCD panel  120 . The backside of the second face  102   b  contacts the first glass substrate  110   a  extended relatively longer than the first polarizing plate  109   a  and a upper portion of the main support  112 . As illustrated in the drawings, the bottom cover  111  encloses side and bottom portions of the main support  112 .  
         [0045]      FIG. 9  is a perspective view illustrating an LCD device according to another embodiment of the present invention and  FIG. 10  is a cross-sectional view taken along the cutting line III-III′ in  FIG. 9 .  
         [0046]     Referring to  FIG. 9 , an LCD device according to another embodiment of the present invention, similar to the former embodiment of the present invention, includes an LCD panel  220  and a main support  201  formed of a non-conductive substance to support the LCD panel  220 . The LCD panel  220  includes first and second glass substrates  210   a  and  210   b  facing each other. First and second polarizing plates  209   a  and  209   b  are formed on surfaces (backsides) of the first and second glass substrates  210   a  and  210   b , respectively. A plurality of switching devices are formed on the second glass substrate  210   b  to switch signals supplied to liquid crystal cells. In addition, a color filter layer, a black matrix and/or a common electrode are, for example, formed on the first glass substrate  210   a.    
         [0047]     The LCD device further includes a backlight unit having a light source  211 , a light guide plate  206 , a reflector  205 , and an optical sheet  207 . The light guide plate  206  guides the light generated from an area corresponding to the size of the LCD panel  220 . The light source  211  is arranged in the vicinity of an end portion of the light guide plate  206 . The light source  211  is enclosed by a lamp housing  208  that reflects the light from the light source  211  toward the light guide  206 . The reflector  205  is arranged under the light guide plate  206  and contacts the light guide plate  206 . The reflector  205  reflects the light from the light guide plate  206  toward the LCD panel  220  and is extended longer than the end portion of the light guide plate  206 . The lamp housing  208  encloses the side of the light guide plate  206  that faces the lamp  211 . Thus, the lamp housing  208  is partially overlapped with the reflector  205 . Alternatively, a plurality of light sources can be provided at more than two sides of the light guide plate  206 . Alternatively, a plurality of light sources can be arranged under the optical sheet in an array form without employing a light guide plate.  
         [0048]     The optical sheet  207  is arranged between the light guide plate  206  and the LCD panel  220  and includes a plurality of individual sheets such as first and second prism sheets  207   a  and  207   b  neighboring to each other, a diffuser  207   c  and the like. The optical sheet  207  refracts the light from the light guide plate  206  toward the LCD panel  220 .  
         [0049]     The LCD panel  220 , the light guide plate  206  and the optical sheet  207  are joined together to minimize a light loss and protect the LCD device from external shocks. Because the LCD panel  220  includes the first and second glass substrates  210   a  and  210   b , which are fragile against the external shocks, the top case  204  encloses edges of the LCD panel, light guide and optical sheet  220 ,  206  and  207  to minimize the light loss and protect the LCD device from external shocks. In particular, the top case  204  is secured to the main support  201  to enclose the edges of the LCD panel  220 .  
         [0050]     The main support  201  is, for example, formed of plastic and formed by a molding process. The main support  201  has at least one or more steps formed on its inner sidewall. In particular, the second polarizing plate  209   b , as illustrated in the drawing, contacts the main support  201 . Alternatively, a periphery of the second glass substrate  210   b  may contact the main support  112 , as illustrated in  FIG. 6 . Moreover, the main support  201  has at least one or more steps corresponding to the light source  211 . The main support  201  has a projection  202  extending from its upper surface, which can be formed during the molding process of the main support  201 . Alternatively, the projection  201  can be attached to the main support  201  after completion of the molding process. The light source  211  and the lamp housing  208  can be secured to the main support  201  by screws, an adhesive agent, soldering or the like.  
         [0051]     The top case  204  encloses a periphery of the LCD device to be in contact with the bottom cover  212 . Each of the top case  204  and the bottom cover  212  is formed of a metal-based material such as stainless steel. The bottom cover  212  is attached to the main support  201  by screws or other means. The bottom cover  212  has a rectangular frame shape having a front portion and a side portion vertical to the front portion to cover the edges of the LCD panel  220 . The top case  204  is attached to the LCD panel  220  when assembling the LCD device. The top case does not directly contact the LCD panel  220  or the main support  201 .  
         [0052]     A coil spring  203  formed of an elastic conductive material is arranged to encase the projection  202  of the main support  201 . The coil spring  203  is attached to the LCD panel  220  together with the top case  204  during the assembly. In particular, a upper part of the coil spring  203  contacts the top case  204  and a lower part of the coil spring  203  contacts the main support  201  and the first glass substrate  201   a . The coil spring  203  electrically grounds the LCD panel  220  to the top case  204  to prevent static electricity from being concentrated on the LCD panel  220 . Although a set of the projection  202  and the coil spring  203  is illustrated in the drawings, a plurality of sets of a projection and a coil spring can be used. The coil spring  203  can have any shape and size, so long as it contacts the main support  201 , the first glass substrate  210   a  and the top case  204  during the assembly. The upper and lower parts of the coil spring  203  can be attached to the top case  204  and/or the main support  201  and/or the first glass substrate  210   a  in the similar manner described above with respect to the plate spring  102  of the former embodiment of the present invention.  
         [0053]     The plate or coil spring discharges static electricity, which is, for example, generated when loading the LCD panel within the top case during the assembly process of the LCD device, to the top case, thereby protecting the LCD panel from the static electricity. Thus, the LCD device of the present invention can use the spring or other compressing means to electrically ground the LCD panel without using a separate conductive tape.  
         [0054]     Accordingly, the present invention provides the following advantages. First of all, an electrically conductive path, via which static electricity is discharged, is formed by the spring (coil or plate) contacting the top case and a periphery of the LCD panel, whereby the LCD panel can be protected against static electricity. Secondly, because the LCD panel is electrically grounded to the top case via the spring (coil or plate), product failure caused by the defective conductive tape can be minimized.  
         [0055]     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.