Abstract:
A housing for a portable information terminal capable of maintaining its strength while the portable information terminal is reduced in weight and thickness, a method of reinforcing the housing, and a portable information terminal using the housing, are provided for.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a housing of a portable information terminal such as a notebook PC, a PDA or a game machine and more particularly to a reinforcing of the structure of the portable information terminal. The present invention also relates to a method of reinforcing the housing and to a portable information terminal using the housing.  
           [0003]    2. Background of the Related Art  
           [0004]    In recent years, with the increasing need to reduce the weight and thickness of portable information terminals, such as notebook PCs, PDAs, and game machines, the strength of housings of portable information terminals has become critical. In other words, based upon market demands, it has become necessary to minimize the thickness of a housing of a portable information terminal in order to reduce the weight and thickness of the portable information terminal. However, a reduction in the thickness of a housing of a portable information terminal, may often result in failure to provide the structural strength required for the portable information terminal.  
           [0005]    For instance, FIG. 6 shows the construction of an ordinary notebook PC as an example of a portable information terminal. In the example shown in FIG. 6, the notebook PC  51  is constructed by attaching a keyboard unit  53  and an LCD panel  54  to a housing  52  made of, for example, electrically conductive CFRP. Attempts have been made to reduce the thickness of the housing  52  in the thus-constructed notebook PC  51  to such a limit as to satisfy the recent weight/thickness reduction requirements. In actual use, however, particularly when a user holds between his or her fingers one or both of two front corners A and B closer to the user as shown in FIG. 6 while the LCD panel  54  is set in the operating state, an excessively large force is applied to the housing  52  through leverage by the weight of the main body of the notebook PC  51  and the weight of the LCD panel  54  with the center of gravity shifted rearward. A design for reducing the weight and thickness of the notebook PC  51  is restricted because of this problem.  
           [0006]    Also in the notebook PC  51 , a metallic base plate constituting the keyboard unit  53  is maintained at ground level to enable the keyboard unit  53  to function as a shielding plate for shielding against external noise and electric wave noise emitted from the PC itself. However, as the notebook PC is further reduced in weight and thickness, the space in the housing  52  becomes so small that it is difficult to maintain the keyboard unit  53  at ground level. Thus, there is a problem that the keyboard unit  53  is not sure to perform the function of a shielding plate for shielding against external noise and electric wave noise emitted from the PC itself.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 illustrates a method of reinforcing a housing of a portable information terminal in a preferred embodiment of the present invention;  
         [0008]    [0008]FIG. 2 illustrates reinforcing members in the method of reinforcing the housing of the portable information terminal of the present invention;  
         [0009]    [0009]FIG. 3 shows an exemplar reinforcing member used in a preferred embodiment of the present invention;  
         [0010]    [0010]FIGS. 4A and 4B illustrate an exemplar keyboard unit used in a preferred embodiment of the present invention;  
         [0011]    [0011]FIG. 5 illustrates an exemplar method for attaching the keyboard unit in the portable information terminal in a preferred embodiment of the present invention; and  
         [0012]    [0012]FIG. 6 shows an exemplar construction of an ordinary notebook PC.  
     
    
     SUMMARY OF THE INVENTION  
       [0013]    A first object of the present invention is to provide a housing of a portable information terminal free from the above-described problems that is capable of maintaining its strength while the portable information terminal is reduced in weight and thickness, a method of reinforcing the housing, and a portable information terminal using the housing.  
         [0014]    A second object of the present invention is to provide a housing of a portable information terminal free from the above-described problems and capable of reliably grounding the keyboard unit and the housing while the portable information terminal is reduced in weight and thickness, a method of reinforcing the housing, and a portable information terminal using the housing.  
         [0015]    The present invention provides, in a first aspect, a housing of a portable information terminal comprising a body having a polygonal outer shape, and a plurality of reinforcing ribs arranged radially from a corner of the body closer to a front side of the body facing a user in practical use. The present invention provides in a second aspect a housing of a portable information terminal comprising a body having a polygonal outer shape, and a plurality of reinforcing members arranged radially from a corner of the body closer to a front side of the body facing a user in practical use. The present invention provides in a third aspect a housing of a portable information terminal comprising a body having a polygonal outer shape, and a plurality of reinforcing ribs and a plurality of reinforcing members, the reinforcing ribs and reinforcing members being arranged radially from a corner portion of the body closer to a front side of the body facing a user in practical use.  
         [0016]    The present invention also provides a method of reinforcing a housing of a portable information terminal having a body having a polygonal outer shape, the method comprising arranging a plurality of reinforcing ribs and/or a plurality of reinforcing members radially from a corner portion of the body of the housing closer to a front side of the body facing a user in practical use. Further, the present invention provides a housing of a portable information terminal comprising a body having a polygonal outer shape, and a plurality of reinforcing ribs and/or a plurality of reinforcing members arranged radially from a corner portion of the body closer to a front side of the body facing a user in practical use.  
         [0017]    According to the present invention, reinforcing ribs and/or reinforcing members are formed radially from a corner closer to a user in practical use to make the housing strong enough to resist even against a force applied through leverage when a user holds the corner between his or her fingers.  
         [0018]    In a preferred embodiment of the present invention in the second or third aspect of the present invention, an EMI contact finger is provided inside at least one of the reinforcing members and it is preferable to arrange the housing so that a keyboard unit is mounted on a portion of the housing on which the reinforcing members are arranged, and so that a base plate of the keyboard unit and the EMI contact finger are brought into contact with each other when the keyboard unit is attached to the housing. Advantageously, in this case, the base plate of the keyboard and the EMI contact finger can be brought into contact with each other at a plurality of points, thereby enabling the base plate of the keyboard unit to be maintained at ground level with reliability.  
       DETAILED DESCRIPTION  
       [0019]    [0019]FIG. 1 illustrates a method of reinforcing a housing of a notebook PC, which is an example of a portable information terminal in accordance with the present invention. A housing  1  shown in FIG. 1 is used in a notebook PC  51  shown in FIG. 6. Referring to FIG. 1, the housing  1  made of, for example, CFRP has a battery bay  2 , an LCD attachment portion  3 , and a keyboard unit attachment portion  4 . An LCD panel not shown is attached to a hinge  7  provided in the LCD attachment portion  3 . The LCD panel can be accommodated in a recess formed by the LCD panel attachment portion  3  and the keyboard unit attachment portion  4 .  
         [0020]    A feature of the present invention resides in the fact that, in the keyboard unit attachment portion  4  of the housing  1 , reinforcing ribs  5 - 1  and  5 - 2  are formed integrally with the housing  1  so as to extend radially from two corners A and B remote from the position at which the LCD panel unit is attached (LCD panel attachment portion  3 ), and closer to the front side of the housing  1  facing a user in practical use. In this example, a plurality of reinforcing ribs  5 - 1  are formed so as to extend radially from the corner A while a plurality of reinforcing ribs  5 - 2  are formed so as to extend radially from the corner B. However, these reinforcing ribs  5 - 1  and  5 - 2  are not provided in a region required to accommodate a circuit board, etc., in the space formed between the housing  1  and the keyboard unit (not shown) placed on the housing  1 . In this example, reinforcing member accommodation portions  6 - 1 ,  6 - 2 , and  6 - 3  for accommodating reinforcing members to be described later are also formed so as to extend radially from the corners A and B.  
         [0021]    [0021]FIG. 2 illustrates reinforcing members in the method of reinforcing the housing of the notebook PC in accordance with the present invention. In FIG. 2, members or portions corresponding to those shown in FIG. 1 are indicated by the same reference characters, and the description for them will not be repeated. Referring to FIG. 2, reinforcing members  11 - 1  are provided so as to extend radially from the corner portion A in correspondence with the reinforcing member accommodation portions  6 - 1  provided in the housing  1 , and reinforcing members  11 - 2  are provided so as to extend radially from the corner B in correspondence with the reinforcing member accommodation portions  6 - 2 . A reinforcing member  11 - 3  is provided along a line connecting the portion A and the corner portion B in correspondence with the reinforcing member accommodation portion  6 - 3  provided in the housing  1 . Each of the reinforcing members  11 - 1 ,  11 - 2 , and  11 - 3  has a generally U-shaped cross section to increase the strength.  
         [0022]    The reinforcing ribs  5 - 1  and  5 - 2  are provided as shown in FIG. 1, or the reinforcing ribs  5 - 1  and  5 - 2  and the reinforcing members  11 - 1 ,  11 - 2 , and  11 - 3  are provided as shown in FIG. 2 to achieve reinforcement of the housing  1 , particularly reinforcement in radial directions from the corner portions A and B, so that deformation or breakage of the housing  1  during handling by a user can be prevented even if the thickness of the housing  1  is minimized. It will be further understood that various changes in the details, materials, and arrangements of the parts which are described and illustrated in order to explain the nature of this invention may be made by those skilled in the art without departing from the principle and scope of the present invention, such that the invention can be achieved by providing a structure different from that shown in FIGS. 1 and 2, such as one having only reinforcing members  11 - 1 ,  11 - 2 , and  11 - 3  and no reinforcing ribs  5 - 1  and  5 - 2 .  
         [0023]    [0023]FIG. 3 shows an exemplar reinforcing member used in accordance with the present invention. In this example, a reinforcing member  11 - 1  is formed so as to accommodate an EMI contact finger  24  in its channel portion of  21  having a generally U-shaped cross section, as described below. Openings  22  are formed in two places in the surface of the channel portion  21  facing the base plate of the keyboard unit when the keyboard unit is attached. The EMI contact finger  24  has raised portions  23  at positions corresponding to the openings  22 . The raised portions  23  project through the openings  22  when the EMI contact finger  24  is accommodated in the channel portion  21 . Similarly, other reinforcing members  11 - 2  and  11 - 3  may be formed in the same manner.  
         [0024]    This configuration of the reinforcing member  11 - 1  enables the base plate of the keyboard unit and the raised portions  23  of the EMI contact finger  24  to contact each other when the keyboard unit is attached to the housing  1 . FIGS. 4A and 4B shows an exemplar keyboard unit  31  used in a preferred embodiment of the present invention. This keyboard unit  31  has input keys  33  provided on an electrically conductive base plate  31 , and allows for signal exchange with the system side through a connector  35  on a connection portion  34 .  
         [0025]    When the keyboard unit  31  is attachably fitted to the housing  1  as shown in FIG. 5, the raised portions  23  is pressed by the base plate  32  of the keyboard unit  31  to recede to the plane on which the openings  22  of the reinforcing member  11 - 1  are formed. In this state, the raised portions  23  are urged upward by the reaction of bending of the EMI contact finger  24 , so that the raised portions  23  and the base plate  32  of the keyboard unit  31  are maintained in contact with each other with reliability. The raised portions  23  and the base plate  32  are kept in contact with each other over the entire surface of the base plate  32  of the keyboard unit  31 . Therefore the base unit  32  can be maintained at ground level with reliability to provide an anti-EMI radiation means as well as to solve the problem of ESD or RF grounding connection.  
         [0026]    More specifically, in the preferred embodiment of the present invention, a loud speaker, an audio card, audio jacks (headphone jack, microphone jack), etc., are provided below the keyboard unit  31 , and these components are connected to a system main unit. If this connection structure is not shielded, there is a possibility of some portion of the connection structure functioning as an antenna for receiving electric waves to induce electric wave noise in the system when, for example, a portable telephone or the like is used near the notebook PC. There is also a possibility of electric waves generated in the system being emitted to the outside. However, the conductive base plate  32  of the keyboard unit  31  and conductive portions of the housing  1  are made to electrically contact each other to avoid such problems. For example, a pointing device controller  36  shown in FIG. 4B converts an operation of a pointing device  37  shown in FIG. 4A into an analog electrical value, amplifies it, and converts it into a digital value. Introduction of electric wave noise into components for processing an analog signal before amplification in such a process is a particularly important problem necessary to be avoided. The arrangement in the preferred embodiment of the present invention allows for solving this problem.  
         [0027]    As is apparent from the foregoing, according to the present invention, reinforcing ribs and/or reinforcing members are formed radially from corners closer to a user in practical use to make the housing strong enough to resist even against a force applied through leverage when a user holds one or both of the corner portions between his or her fingers. Also, in the preferred embodiment, the base plate of the keyboard unit can be maintained at ground level with reliability.