Abstract:
A mobile terminal having a liquid crystal display apparatus, which includes a liquid crystal panel having a polygonal flat shape and an adhesion member installed on at least one part among edges except corner parts at the flat portion of the liquid crystal panel. The mobile terminal includes a transmission and reception unit positioned at one side of a case, an input adjusting unit exposed to external portion of the case, a control unit, and a liquid crystal display driving unit operated by an output signal of the control unit, Accordingly, the mobile terminal with the liquid crystal display apparatus features improved durability and reliability since the liquid crystal panel has minimized spot generation that may occur from physical impacts, temperature changes or applied wrenching loads.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a liquid crystal display apparatus and a mobile terminal which display letter or image information and particularly, to a liquid crystal display apparatus and a mobile terminal having a liquid crystal panel which does not easily get out of order by an external impact. 
     2. Description of the Background Art 
     Generally, Liquid Crystal Display (LCD) is a displaying apparatus installed in a mobile terminal, monitor and the like and liquid crystal which is a material between liquid and solid condition is injected between two sheets of glass substrates formed as electrodes to display letters or images by adding an electric field. 
     As shown in FIG. 1, such liquid crystal display apparatus is installed in folder-type mobile terminal  1  and the like to display adjust or use condition or letter or image information, etc. 
     Particularly, since a liquid crystal panel composing the liquid crystal display apparatus can not emit light by itself, a back light sheet is installed at the rear side and accordingly letter or image information displayed on the liquid crystal panel can be recognized more clearly by penetrating light emitted from the back light sheet. 
     The back light sheet mainly employs a direct method for directly illuminating the front surface of the liquid crystal panel using Electro luminescence (EL) or an edge method for illuminating the liquid crystal panel using light diffused by a light transmission board having light sources at one or two sides of the liquid crystal panel. Between the methods, the liquid crystal display apparatus having a back light sheet by the direct method is mainly used for miniature electric devices such as mobile terminals and the like. 
     FIG. 2 is an exploded perspective view showing a conventional liquid crystal display apparatus by the direct method. 
     With reference to FIG. 2, the liquid crystal display apparatus  10  positioned in a mobile terminal is inserted-installed in a frame  17  fixed in a case of the terminal and as shown in FIG. 1, it displays letter or image information through a viewing window. 
     Since such liquid crystal display apparatus  10  has a liquid crystal panel  11 , a Flexible Printed circuit (FPC)  12  is connected to the liquid crystal panel  11  and a reflection board  13  for reflecting light incident from the liquid crystal panel  11  is adhered to the rear surface as a single body. 
     The back light sheet  15  formed as a flat board shape, for illuminating the liquid crystal panel  11  is positioned on the rear surface of the liquid crystal panel  11  where the reflection board  13  is attached. Here, the reflection board  13  penetrates the light emitted from the back light sheet  15  in the direction of the liquid crystal panel  11 . 
     Here, the reflection board  13  and back light sheet  15  forming the rear surface of the liquid crystal panel  11  are mutually attached by a double-faced adhesive tape  20 . 
     Therefore, the liquid crystal panel  11 , reflection board  13  and back light sheet  15  form a liquid crystal panel assembly and the liquid crystal panel assembly is inserted-assembled in the frame  17 . 
     Particularly, the double-faced adhesive tape  20  is formed in a square band shape not to interfere the light illuminated from the back light sheet  15  and maintain an adhesive force between the liquid crystal panel  11  and back light sheet  15  and is adhered to the circumferential portions  13 P and  15 P between the reflection board  13  and back light sheet  15  adhered to the liquid crystal panel  11  as a single body. 
     As shown in FIG. 3, the double-faced adhesive tape  20  is adhered to the inner surface  17 A of the frame  17  in FIG. 2 having some portions  20 A and  20 B which are formed protruded further than the periphery of the back light sheet  15 . 
     On the other hand, as shown in FIG. 2, a polarizing plate  19  for forwardly penetrating the light penetrated through the liquid crystal panel  11  at the front side of the liquid crystal panel  11 . 
     However, since in the conventional liquid crystal display apparatus, the double-faced adhesive tape  20  is adhered to the circumferential surface of the liquid crystal panel  11  and back light sheet  15 , the liquid crystal panel  11  is easily transformed or broken by external impacts. 
     Namely, as shown in FIG. 3, since all parts of the liquid crystal panel  11  are adhered and bound to the back light sheet  15  by the double-faced adhesive tape  20 , when instantaneous impact is applied as in the case that the liquid crystal display apparatus falls and is collided with a bottom, the lower substrate  11 B of the liquid crystal panel  11  is adhered to the back light sheet  15  as a single body by the reflection board  13  and fixed to the frame  17  as shown in FIG.  4 . However, the upper substrate  11 A performs relative movement minutely contrary to the lower substrate  11 B by the falling impact and the upper substrate  11 A and the lower substrate  11 B are instantaneously cracked apart in the “A” and “B” directions. 
     When the upper substrate upper substrate  11 A and the lower substrate  11 B are instantaneously cracked apart, vacuum foams are formed from the liquid crystal  11 C filled between the both substrates  11 A and  11 B to the space cracked apart and a bleeding phenomenon of an exploded dotted pattern regardless of the inputted display signal. In the excessive case, letter or image information can not be clearly displayed by the bleeding phenomenon. 
     Particularly, in case of using a mobile communication instrument such as a mobile terminal, the bleeding phenomenon is often occurred when the instrument falls. At this time, as shown in FIG. 5, by the impact, the corner parts are damaged by the bleeding phenomenon and letter or image information is not displayed clearly. 
     Here, FIG. 5A shows the initial stage of the bleeding phenomenon that spots are occurred on the liquid crystal panel  11  right after the mobile terminal  1  falls in case the liquid crystal display apparatus  10  is installed in the mobile terminal  1  and FIG. 5B shows the bleeding expansion phenomenon that the spot (BL) is gradually expanded after 24 hours after the falling. 
     SUMMARY OF THE INVENTION 
     Therefore, to solve the above problem, the present invention provides a liquid crystal display apparatus and a mobile terminal capable of improving durability of the liquid crystal panel minimizing spot generation even though impacts by a falling or temperature change or a certain wrenching load is applied, by installing double-faced adhesive tape only at the edge portions except corner parts of the liquid crystal panel and the back light sheet and composing the liquid crystal panel and the back light sheet to be mutually adhered. 
     To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a liquid crystal display apparatus including a liquid crystal panel having a polygonal flat shape, a back light sheet positioned on the rear surface of the liquid crystal panel, for illuminating the liquid crystal panel with light and an adhesion member for mutually adhering the liquid crystal panel and the back light sheet by forming adhesion force in at least one part among edges except corner parts between the liquid crystal panel and the back light sheet. 
     Also, a mobile terminal for achieving the above object includes a transmission and reception means positioned at one side of a case, an input adjusting means exposed to external portion of the case being adjusted by a user, a control means for outputting a driving signal according to an input signal of the input adjusting means at the same time when the signals are inputted and outputted, being connected to the transmission and reception means, a liquid crystal display driving means operated by the output signal of the control means, a liquid crystal panel positioned in the case so that it can be shown from the outside, for displaying letter or image information by the liquid crystal display driving means and an adhesion member installed at least one part among edges except corner parts at the flat portion of the liquid crystal panel for supporting the liquid crystal panel in the case. 
     The foregoing and other, features, aspects and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     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 specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. 
     In the drawings: 
     FIG. 1 is a perspective view showing a conventional mobile terminal; 
     FIG. 2 is an exploded perspective view showing the conventional liquid crystal display apparatus; 
     FIG. 3 is a perspective view showing the condition that a conventional liquid crystal panel and back light sheet are adhered; 
     FIG. 4 is a view showing the conventional liquid crystal panel changed by a falling impact; 
     FIGS. 5A and 5B are a view showing a bleeding of the conventional liquid crystal panel by the falling impact; 
     FIG. 6 is a block diagram showing a mobile terminal in accordance with the present invention; 
     FIG. 7 is an exploded perspective view showing a liquid crystal display apparatus in accordance with the embodiment of the present invention; 
     FIG. 8 is a perspective view showing the condition that a liquid crystal panel and back light sheet in accordance with an embodiment of the present invention are adhered; 
     FIG. 9 is an exploded perspective view showing the liquid crystal display apparatus in accordance with other embodiment of the present invention; and 
     FIG. 10 is a perspective view showing the condition that the liquid crystal panel and back light sheet in accordance with the other embodiment of the present invention are adhered. 
    
    
     DETAILED DESCRIPTION OF THE 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. 
     FIG. 6 is a block diagram showing a folder-type mobile terminal in accordance with the present invention. 
     The mobile terminal in accordance with the present invention  40  includes a transmission and reception unit  43  positioned at the side of a folder  41 , an input adjusting unit  44  exposed to the upper surface of the main body  42  being adjusted by a user, a control unit  45  connected with the transmission and reception unit  43 , for outputting a controlling driving signal according to an input signal of the input adjusting unit  44  at the same time when the signals are inputted and outputted, being connected to the transmission and reception unit  43 , a liquid crystal display driving unit  47  operated by the output signal of the control unit  45  and a liquid crystal display apparatus  49  positioned inside the folder  41  so that it can be shown from the outside, for displaying letter or image information by the operation of the liquid crystal display driving unit  47 . 
     FIGS. 7 and 8 are views showing the liquid crystal display apparatus positioned in the mobile terminal in accordance of an embodiment of the present invention. FIG. 7 is an exploded perspective view showing a liquid crystal display apparatus in accordance with an embodiment of the present invention and FIG. 8 is a perspective view showing the condition that a liquid crystal panel and back light sheet in accordance with an embodiment of the present invention are adhered. 
     The liquid crystal display apparatus in accordance of an embodiment of the present invention is installed in a frame  70  fixed in the folder of the mobile terminal shown in FIG.  6  and can display letter or image information through a viewing window of the folder  41 . 
     The liquid crystal display apparatus  49  has a liquid crystal panel  50  having a square flat shape and a FPC  55  is connected to the liquid crystal panel  50 . A reflection board  60  for reflecting light incident from the side of the liquid crystal panel  50  in the front direction is adhered to the rear surface of the panel as a single body. 
     On the rear surface of the panel  50  where the reflection board  60  is attached, a back light sheet  65  formed in a square flat shape, for irradiating light to the liquid crystal panel  50  is positioned and the reflection board  60  and the back light sheet  65  forming the rear surface of the liquid crystal panel  50  are mutually adhered by the plurality of double-faced adhesive tapes  80 . 
     Namely, the double-faced adhesive tape  80  is adhered to the four edges  60 P and  65 P except the four corners in the reflection board  60  and the back light sheet  65  and accordingly, the liquid crystal panel  50  and the back light sheet  65  can be mutually adhered to each other. 
     Here, it is desirable that the double-faced adhesive tapes  80  are installed at four all edges of the liquid crystal panel  50  and the back light sheet  65  and according to the design condition the tapes can be installed only at two parts opposing to each other. 
     The liquid crystal panel  50  and the back light sheet  65  adhered to the double-faced adhesive tape  80  are adhered to each other as a single body and form a liquid crystal panel assembly and the liquid crystal panel assembly is inserted-assembled in the frame  70 . 
     On the other hand, reference numeral  75  in FIG. 7 is a polarizing plate positioned at the front side of the above liquid crystal panel  50  for penetrating light penetrated through the liquid crystal panel  11 . 
     FIGS. 9 and 10 are views showing the liquid crystal display apparatus in accordance with other embodiment of the present invention. FIG. 9 is an exploded perspective view showing the liquid crystal display apparatus and FIG. 10 is a perspective view showing the condition that the liquid crystal panel and back light sheet are adhered. 
     The liquid crystal display apparatus in accordance with other embodiment of the present invention has a reflection board  55 ′ adhered to the rear surface of the liquid crystal panel  50 ′ as a single body and on the rear surface of the liquid crystal panel  50 ′, a back light sheet  65 ′ is attached by a plurality of double-faced adhesive tapes  80 ′ as in the above described embodiment. 
     Particularly, the double-faced adhesive tapes  80 ′ are adhered to only four corner parts except four edges of the reflection board  60 ′ and the liquid crystal panel  50 ′ and two of the four double-faced adhesive tapes are adhered to the inner surface  70 A′ of the frame  70 ′ having parts  80 A′ and  80 B′ protruded further outwardly than the periphery of the liquid crystal panel  50 ′ and back light sheet  65 . 
     Finally, the liquid crystal panel  50 ′ and back light sheet  65 ′ are adhered to each other as a single body by the double-faced adhesive tapes  80 ′ and the liquid crystal panel assembly is inserted in the frame  70 ′ and adhered and supported by the frame  70 ′ by the two double-faced adhesive tapes  80 ′. 
     The operation of the liquid crystal display apparatus having the above composition in accordance with the present invention will be described as follows. 
     When heat impact, wrenching load and falling impact are applied to the folder-type mobile terminals having the liquid crystal display apparatuses in accordance with the present and conventional arts, as shown in FIG. 5, inferiority, that is, the bleeding phenomenon was occurred. 
     
       
         
               
               
               
               
             
           
               
                   
               
               
                 kind of 
                 conventional 
                 present art 
                 present art 
               
               
                 experiment 
                 art 
                 (an embodiment) 
                 (other embodiment) 
               
               
                   
               
             
             
               
                 heat impact 
                 61 
                 0 
                 0 
               
               
                 wrenching load 
                 60 
                 0 
                 0 
               
               
                 falling impact 
                 62 
                 0 
                 0 
               
               
                   
               
             
          
         
       
     
     Numeral values according to each experiment in the above table are results that 100 folder-type mobile terminals are tested and among factors according to each experiment of each terminal, the heat impact experiment was repeated 6 times varying temperature from −30 to 80° C., the wrenching experiment was conducted by repeating a wrenching load of 3.7 kg 30,000 times and the falling impact experiment was conducted by failings of 6 surfaces of a terminal respectively one time under the condition that the folder was closed and by fallings of 6 surfaces of a terminal respectively one time under the condition that the folder was opened. 
     As shown in the above table, the liquid crystal display apparatus in accordance with the present invention binds edge parts of the liquid crystal panel  50  and the back light sheet  65  under the condition that they are mutually adhered by attaching the double-faced adhesive tapes  80  only to edge parts except the corner parts of the flat surface of the liquid crystal panel  50  but the corner parts of the liquid crystal panel  50  is not bound to the back light sheet  65  or frame  70 . 
     Therefore, since when heat impact, wrenching load and falling impact are applied to the mobile terminal having the liquid crystal display apparatus in accordance with the present invention, the corner parts where the bleeding phenomenon is easily occurred in the liquid crystal panel  50  is not bound, the phenomenon that the upper and lower substrates are cracked apart is minimized as shown in FIG.  4  and the bleeding phenomenon in the spot shape can be prevented, thus to reduce inferiority of the liquid crystal display apparatus. 
     In the liquid crystal display apparatus in accordance with the present invention with the above composition and operation, the double-faced adhesive tape is installed only edge parts except the corner parts of the liquid crystal panel and the liquid crystal panel and the back light sheet can be attached to each other. Accordingly, spot generation is minimized even if impacts by varying temperature and falling or a certain wrenching load is applied and durability of the liquid crystal panel can be increased. 
     Also, in the liquid crystal display apparatus in accordance with the present invention with the above composition and operation, since the liquid crystal display apparatus is installed, damage of the liquid crystal panel by external impacts can be minimized and the efficiency of the display unit conducted by the liquid crystal panel is not decreased, thus to improve reliability of the terminal. 
     As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.