Abstract:
Disclosed is a portable terminal device, which has a reduced thickness, while ensuring a strength with which a display unit can be excellently held. In the device ( 100 ), the flat-board-like display unit ( 200 ) provided with a display drive section ( 213 ) that drives a liquid crystal display section ( 211 ) is attached to a first case ( 110 ) with a metal rear plate ( 160 ) therebetween. The rear plate ( 160 ) is provided with a reinforcing section ( 180 ), which is formed by folding back one plate end portion, which has a predetermined width, a plurality of times into a roll-shape on the rear surface side of the rear plate ( 160 ). The reinforcing section ( 180 ) is disposed at a position that includes the horizontal projection area of the display drive section ( 213 ), and prevents stress from concentrating on the display drive section ( 213 ) by reinforcing the display drive section ( 213 ).

Description:
TECHNICAL FIELD  
       [0001]    The present invention relates to a portable terminal apparatus such as a mobile telephone having a display section. 
       BACKGROUND ART  
       [0002]    Conventionally, a flat display unit such as a liquid crystal display (LCD) including a liquid crystal panel and a backlight has been widely used as a display section of a radio portable terminal apparatus (hereinafter just referred to as a portable terminal apparatus) such as a mobile telephone. 
         [0003]    For example, the LCD is arranged to face a backlight module radiating light to the liquid crystal display module, on the rear surface of the liquid crystal display module that includes a glass substrate sandwiching a plurality of liquid crystal cells, and a liquid crystal drive IC configured at a stretching portion corresponding to the end of the glass substrate. 
         [0004]    A flat display unit such as LCD is configured as mentioned above and is mounted on a mobile telephone, for example, so as to be placed on a flat portion provided for a casing of the mobile telephone. 
         [0005]    Generally, the flat display unit mounted for a mobile telephone configures a display section by arranging in a casing on the surface mounted with a speaker that sounds out speech of an intended party, so that a shock might be applied near the display section such as when a user presses the user&#39;s ear against the mobile telephone while in use. 
         [0006]    The shock might concentrate a stress on the liquid crystal drive IC configured on the glass substrate of the flat display unit that configures the display section. Therefore, for example, Patent Literature 1 arranges the glass substrate on a metal frame, and the frame is processed to form a bridge at a position corresponding to the stretching portion of the liquid crystal drive IC or the glass substrate in order to increase the strength of the LCD itself. 
       Citation List 
     Patent Literature 
     PTL 1 
       [0007]    Japanese Patent Application Laid-Open No. 2009-9820 
       SUMMARY OF INVENTION  
     Technical Problem 
       [0008]    Recently, there is a demand that portable terminals such as mobile telephones equipped with liquid crystal display units to be thinner as well as less power consuming and lighter. 
         [0009]    According to a conventional configuration as described in Patent Literature 1, a bridge portion is formed on the frame by bending its metal base portion arranged at the rear surface of a stretching portion of the glass substrate, in the cross section of the U shape toward the mounting surface. That is, a bridge portion has configuration where a flat plate section bridged on upper ends of a portion raised from the bottom of the bridge portion decreases the stress concentration by supporting the stretching portion of the glass substrate at higher place than the bottom surface, so that the liquid crystal display unit itself thickens by a height of the raised portion. A recessed portion is formed on the raised portion described in Patent Literature 1 and reinforces the raised portion. Therefore, the raised portion needs to have a predetermined length to ensure an area for forming the recessed portion, so that this makes the liquid crystal display unit difficult to be much thinner. 
         [0010]    It is therefore an object of the present invention to provide a portable terminal apparatus that can be thinner while ensuring a strength enough to satisfactorily hold a display unit. 
       Solution to Problem 
       [0011]    One aspect of the portable terminal apparatus of the present invention includes: a display unit having a display section, the display unit being flat; a rear plate where the display unit is mounted on a surface, the rear plate being metal; and a casing to which the rear plate is attached, where the rear plate employs a configuration to include a reinforcing section that is formed by repeatedly folding one end with a specified width on a rear surface side of the rear plate and allows a repeatedly folded portion to be layered on the rear surface side of the rear plate. 
       Advantageous Effects of Invention 
       [0012]    The present invention can provide a portable terminal apparatus that can be thinner while ensuring a strength enough to satisfactorily hold a display unit. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0013]      FIG. 1  is a perspective view showing a portable terminal apparatus according to an embodiment of the present invention; 
           [0014]      FIG. 2  is an exploded perspective view showing a first casing including a display section in the portable terminal apparatus shown in  FIG. 1 ; 
           [0015]      FIG. 3  is an A-A line cross-sectional view of the portable terminal apparatus shown in  FIG. 1 ; 
           [0016]      FIG. 4  is a schematic diagram showing a reinforcing section of the portable terminal apparatus according to the present embodiment; 
           [0017]      FIG. 5  is a schematic diagram showing a strength against deflection; and 
           [0018]      FIG. 6  is a schematic diagram showing a modification example of the reinforcing section in the portable terminal apparatus according to the present embodiment. 
       
    
    
     DESCRIPTION OF EMBODIMENTS  
       [0019]    Now, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 
         [0020]      FIG. 1  is a perspective view showing portable terminal apparatus  100  according to an embodiment of the present invention. The present embodiment describes portable terminal apparatus  100  as a mobile telephone, but the invention is not limited thereto and is also applicable to any electronic apparatuses as portable terminal apparatuses having display sections. 
         [0021]    Portable terminal apparatus  100  shown in  FIG. 1  is a flip mobile telephone. In portable terminal apparatus  100 , second casing  140  having operation section  130  is rotatably coupled to first casing  110  having display surface  112  through connection section  150 . Portable terminal apparatus  100  may also represent a slide or straight model mobile telephone equipped with the display section. 
         [0022]    In second casing  140 , operation section  130  is arranged on surface  142  where folded first casing  110  is placed. On the other hand, in first casing  110 , display unit  200  (see  FIGS. 2 and 3 ) is arranged on a surface (equivalent to display surface  112 ) opposite to surface  142  of second casing  140  when the portable terminal apparatus is folded, display unit  200  displaying data through transparent display panel  114  that configures display surface  112 . Surface  142  of second casing  140  is arranged with a microphone that collects speech from a user, and display surface  112  of first casing  110  is arranged with a speaker (not shown) that sounds out speech from an intended party. 
         [0023]      FIG. 2  is an exploded perspective view showing the first casing including the display section in the portable terminal apparatus shown in  FIG. 1 , and  FIG. 3  is an A-A cross-sectional view of the portable terminal apparatus shown in  FIG. 1 . 
         [0024]    As shown in  FIG. 2 , on first easing  110  of portable terminal apparatus  100  (see  FIG. 2 ), metal rear plate  160  is attached to casing frame section  115  that is formed into a rectangular frame shape, and display unit  200  having display section  211  is mounted on this rear plate  160 . In first casing  110 , casing frame section  115  is attached to an opening side of box-shaped casing body  113 . 
         [0025]    Although display unit  200  is shaped into a flat plate and is described here as a liquid crystal display unit including display section  211  using a liquid crystal module, this is not limited thereto and it is possible to be an organic EL display unit including a display section that uses an EL element. 
         [0026]    Display unit  200  includes display module  210  that includes display section (hereinafter referred to as a “liquid crystal display section”)  211  including a plurality of liquid crystal cells sandwiched between glasses, and display drive section (or herein referred to as liquid crystal display drive section (liquid crystal display drive  1 C))  213  formed at stretching end  211   a,  that is, a stretching end (a stretching part from an effective display area) of a glass at the bottom side of liquid crystal display section  211 . Display module  210  configures a planar surface where one of surfaces of liquid crystal display section  211  is assumed as display surface  211   b . Display unit  200  includes this display module  210  and backlight module  220  that is attached to a rear surface of liquid crystal display section  211  in display module  210  and radiates light to liquid crystal display section  211 . 
         [0027]    Here, liquid crystal display section  211  is shaped into a rectangular plate and radiated light of surface emitting from backlight module  220  that is arranged on a surface (rear surface) opposite to display surface  211   b.    
         [0028]    As shown in  FIG. 3 , backlight module  220  includes a surface-emitting section including rectangular light guide plate  222  arranged at the rear surface of liquid crystal display section  211  so as to cover the effective display area of liquid crystal display section  211 , and backlight frame section  224  holding liquid crystal display section  211  together with the surface-emitting section. 
         [0029]    Here, light guide plate  222  in the surface-emitting section is attached all over the rear surface of liquid crystal display section  211  and emits from the surface by the light radiated inside from light emitting element  226  such as an LED arranged at the side end of light guide plate  222  which surface is emitting. In light guide plate  222 , it is also possible to layer in order, for example, a diffusion sheet, a prism sheet (light-collection sheet), and a rim sheet, all over the plane (surface) facing liquid crystal display section  211 . The diffusion sheet transmits and diffuses incident light and the prism sheet outputs incident light so that the traveling direction of the incident light is adjusted to be orthogonal to the light-emitting face. The rim sheet is a light-blocking double-sided adhesive tape and is formed such that outgoing light from light guide plate  222  is radiated to the effective display area (area to display images) of liquid crystal display section  211 , Bonds backlight module  220  including light guide plate  222  is integrally pasted to liquid crystal display section  211  through the rim sheet. 
         [0030]    In display unit  200 , display drive section (herein, referred to as “liquid crystal display drive section”)  213  formed at stretching end  211   a  of liquid crystal display section  211  connects with end  215   a  of FPC (Flexible Printed Circuit)  215  that is connected to a main substrate (not shown). One end  215   a  of FPC  215  electrically connects with such as light emitting element  226  as well as display drive section  213  that drives liquid crystal display section  211 . 
         [0031]    FPC  215  extends from the edge portion of the end on the surface to the rear surface at the one end (stretching end  211   a ) of display unit  200  and is bent so as to cover the one end, passes through FPC through-hole (insertion hole)  116  formed in casing frame section  115 , and is guided into first casing  110  (casing body  113  in more detail). In this manner, FPC  215  is connected to the main substrate (not shown) arranged in first casing  110 . 
         [0032]    Rear plate  160  is attached to a frame shape part of casing frame section  115  from the rear surface side and one end part of rear plate  160  is arranged along one side of FPC through-hole  116  in casing frame section  115 . 
         [0033]    FPC through-hole  116  is formed in casing frame section  115  along one end part at the front end, when the end connected to the second casing through the connection section is assumed to be a base end. Edge portion  115   a  at the base end restricted by FPC through-hole  116  is reinforced by reinforcing section  180  formed by repeatedly folding end part (one end)  161  of rear plate  160 . Reinforcing section  180  is formed such that a part of rear plate  160  overlaps with each other in the direction of plate thickness on the rear surface side of rear plate  160 . 
         [0034]    To form reinforcing section  180 , the one end of rectangular rear plate  160  is repeatedly folded so as to be rolled on the side opposite to display unit  200 , the one end having the same length as a longer side of FPC through-hole  116 . 
         [0035]    Reinforcing section  180  extends in a shorter direction of first casing  110  and is formed into a long and narrow flat plate having a predetermined thickness at the folded portion that forms a layer. 
         [0036]    Reinforcing section  180  is positioned at a reversely projected portion corresponding to display drive section  213  of display unit  200  mounted on rear plate  160 , that is, the position including a horizontal projection area. Reinforcing section  180  is formed on rear plate  160  at an opening edge of FPC through-hole  116  so as to cross the center of FPC through-hole  116  in a width direction (the center of lengthwise direction). 
         [0037]    As shown in  FIG. 3 , reinforcing section  180  is disposed near FPC through-hole  116  (edge portion  115   a  as the longer opening edge of FPC through-hole  116 ) so as to overlap with disposition area B for display drive section  213 . Disposition area C for reinforcing section  180  covers disposition area B for display drive section  213 . Reinforcing section  180  is formed by repeatedly folding the end of rear plate  160  so that a plurality of plate-like portions (folded portions) overlap with each other for a predetermined length while so as to keep disposition area B for display drive section  213  smaller than disposition area C for reinforcing section, that is, by layering. 
         [0038]    Specifically, reinforcing section  180  is formed by folding one end of rear plate  160  toward the face opposite to the other face where display unit  200  is mounted on rear plate  160 , and folding again so as to be longer than the width of display drive section  213  (the length of disposition area B for display drive section  213 ). 
         [0039]    The second folded portion is placed between the first folded portion and rear plate  160  so as to form a rolled shape. 
         [0040]      FIG. 4  is a schematic diagram showing a reinforcing section of the portable terminal apparatus according to the embodiment of the present invention. 
         [0041]    As shown in  FIG. 4 , reinforcing section  180  ensures bend heights H and h by repeatedly folding rear plate  160 . As shown in  FIG. 5 , this is because, according to the equation for a cross-section second moment of area I=bh 3 /12 applicable to rectangular-shape cross section D having width b and height h, ensuring bend heights H and h can provide the effect of the cube rather than increasing the plate thickness (equivalent to b), so that it is possible to increase the strength effectively. 
         [0042]    Although reinforcing section  180  is explained to have a configuration formed by folding a part of rear plate  160  into a rolled shape, this is not limited thereto. 
         [0043]    On rear plate  160  (see  FIG. 3 ) of first casing  110  (see  FIG. 3 ) for portable terminal apparatus  100 , reinforcing section  190  (see  FIG. 6 ) may be formed by repeatedly folding (zigzag-folding) a part of rear plate  160  on the place where the reinforcing section is formed, so that three or more folded portions are layered in a direction of overlapping two sides of each folded portion. 
         [0044]    Reinforcing section  190  shown in  FIG. 6  can ensure bend heights h at both ends of the folded and overlapping portion, and by this means increase the strength of reinforcing section  190  itself. 
         [0045]    In this manner, reinforcing sections  180  and  190  reinforce the vicinity of through-hole  116  in casing frame section  115  and reinforces the whole of display drive section  213 . 
         [0046]    According to a conventional configuration, the FPC through-hole to pass through FPC is formed in the first casing, corresponding to the stretching portion of the extending FPC on the glass substrate mounted with the liquid crystal drive IC in the display unit, so that it is difficult to ensure the strength. 
         [0047]    In portable terminal apparatus  100  according to the present embodiment, however, reinforcing sections  180  and  190  are formed near FPC through-hole  116  along the lengthwise direction (width direction) of FPC through-hole  116 . Reinforcing sections  180  and  190  are formed on rear plate  160  at an opening edge of FPC through-hole  116  so as to cross the center of FPC through-hole  116  in the width direction (the center of lengthwise direction). This enables to ensure the strength at the opening edge of FPC through-hole  116 . 
         [0048]    Reinforcing sections  180  and  190  are formed at the position overlapping with display drive section (display drive IC)  213  of mounted display unit  200  in the area covering the horizontal projection area for the display drive IC, so that it is possible to decrease deflection of display drive section (display drive IC)  213  and reduce stress concentration. In addition, reinforcing sections  180  and  190  are formed as an elongated plate-like body having the bend height for the repeatedly folded portion, just by repeatedly folding a part of rear plate  160  where display unit  200  is mounted, toward the face opposite to the other face where display unit  200  is mounted. Therefore, there is no need to ensure a raised height in such a casing that the rear plate is raised to configure the reinforcing section, so that it is possible to easily improve the strength. 
         [0049]    By this means, even if a shock may be applied to display unit  200  through display panel  114  when a user presses the user&#39;s ear against display surface  112  of first casing  110  while using portable terminal apparatus  100 , the portable terminal apparatus decreases the amount of casing deformation (deflection) applied to display drive section  213  and stretching end  211   a  and alleviates stress concentration. Accordingly, it is possible to make a portable terminal apparatus thinner, while ensuring the strength enough to satisfactorily hold display unit  200 . 
         [0050]    Although the present embodiment has explained that the liquid crystal display unit configures the display section supported by the rear plate, an organic EL (Electro-Luminescence) display unit may be used. In this case, reinforcing sections  180  and  190  reinforce an organic EL display drive IC so as to cover the horizontal projection area in the disposition area for the organic EL display drive IC, in the same manner as reinforcing the liquid crystal display drive section (liquid crystal display drive IC) as display drive section  213 . When using the organic EL display unit instead of the liquid crystal display unit, there is no need to use a backlight module, so that it is possible to make a portable terminal apparatus thinner moreover. 
         [0051]    The disclosure of Japanese Patent Application No. 2009-242452, filed on Oct. 21, 2009 including the specification, drawings and abstract, is incorporated herein by reference in its entirety. 
       INDUSTRIAL APPLICABILITY  
       [0052]    The portable terminal apparatus according to the present invention ensures a strength enough to satisfactorily hold a display unit, provides an effect of being made thinner, and is useful as a mobile telephones. 
       REFERENCE SIGNS LIST  
       [0053]      100  Portable terminal apparatus
 
 110  First casing
 
 112  Display surface
 
 113  Casing body
 
 115  Casing frame section
 
         116  Through-hole 
       [0054]      140  Second casing
 
 160  Rear plate
 
         161  One end 
       [0055]      180 ,  190  Reinforcing section
 
 200  Display unit
 
 211  Liquid crystal display section
 
 213  Display drive section