Abstract:
According to an aspect of the present invention, there is provided a portable terminal including: a first housing; a second housing slidable in a sliding direction with respect to the first housing; a first magnet disposed in the first housing; a second magnet disposed in the second housing to face the first magnet in a closed state; and a third magnet disposed in the second housing to face the first magnet in an opened state, wherein an S pole of the first magnet is positioned on a side of the first housing facing the second housing, and wherein an N pole of the second magnet, an S pole of the second magnet, an S pole of the third magnet and an N pole of the third magnet are aligned as a sequence along the sliding direction.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from Japanese Patent Application No. 2009-137579 filed on Jun. 8, 2010, the entire contents of which are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    An aspect of the present invention relates to a housing siding type portable terminal in which magnets for generating both assisting force and holding force in accordance with a user&#39;s operation of sliding a housing are provided. 
         [0004]    2. Description of the Related Art 
         [0005]    In a housing sliding type portable terminal, a spring and magnets are used for assistance and holding in order to make a user&#39;s sliding operation smooth. 
         [0006]    There is a sliding mechanism using such magnets (e.g. see JP-2008-113067-A). Magnetic force in the sliding mechanism of JP-2008-113067-A will be described below. 
         [0007]      FIG. 3  illustrates a magnetic force corresponding to  FIGS. 12C and 12D  and paragraph [0046] in JP-2008-113067-A. In  FIG. 3 , (A) shows a close position, and (C) shows an open position. A housing  204  is provided with one magnet  402 . A housing  202  is provided with two magnets  404  and  406 . 
         [0008]    The center position of the magnet  402  in the one-magnet housing  204  is slid between a position P 1  (close position) and a position P 7  (open position) relative to the two-magnet housing  202 . 
         [0009]    In (D) of  FIG. 3 , respective arrows express a magnetic force in a sliding direction applied on the one-magnet housing  204  in respective positions between P 1  and P 7 . In (E) of  FIG. 3 , arrows and a dotted graphic curve express a repulsive force perpendicular to a principal surface, that is, a floating force applied on the one-magnet housing  204  in respective positions between P 1  and P 7 . 
         [0010]    In (D) of  FIG. 3 , sliding force in P 1  (close position) is substantially zero because the respective center positions of the magnets  402  and  404  coincide with each other. In P 2  or P 3 , rightward force to restore the center position of the magnet  402  to P 1  (close position) is generated. In P 4  (intermediate position), the magnet  402  is located at a middle point between the magnets  404  and  406 , and sliding force is zero. The magnet  402  in P 4  is however so unstable as to be apt to move either left or right. In P 5  or P 6 , leftward force to move the center position of the magnet  402  to P 7  (open position) is generated. In P 7  (open position), sliding force is substantially zero because the respective center positions of the magnets  402  and  406  coincide with each other. 
         [0011]    When a user pushes the housing  204  against such generated sliding force so that the center position of the magnet  402  moves from P 1  (close position) to the left against rightward sliding force in P 2  and P 3 , the center position of the magnet  402  is slid to P 7  (open position) via P 5  and P 6  by leftward sliding force and held in P 7  after the center of the magnet  402  goes beyond P 4  (intermediate position). 
         [0012]    Accordingly, the user needs to push the housing  204  continuously up to a position corresponding to a half of the sliding distance. After the center of the magnet  402  goes beyond the half position, the housing  204  is abruptly slid by sliding force. 
         [0013]    In a direction of floating force in (E) of  FIG. 3 , adsorbing force by which the magnets attract each other in a direction perpendicular to the principal surface is generated in P 1  (close position) and P 7  (open position). Floating force due to repulsion of the magnets in the direction perpendicular to the principal surface is generated in a range of from P 2  to P 6 . 
         [0014]    There is also a slide type portable terminal using magnets (e.g. see JP-2007-288436-A). Magnetic force concerned with a sliding mechanism disposed in JP-2007-288436-A will be described below. 
         [0015]      FIG. 4  illustrates a magnetic force corresponding to  FIG. 5  and paragraphs [0048] to [0060] in JP-2007-288436-A. In  FIG. 4 , (A) shows a closed state, and (C) shows an opened state. A housing  3  is provided with one magnet  21 . A housing  2  is provided with three magnets  8 A,  8 B and  8 C. Magnetic poles of the respective magnets on facing sides of the housings are put in parentheses. 
         [0016]    The center position of the magnet  21  in the one-magnet housing  3  is slid between a position P 1  (close position) and a position P 7  (open position) relative to the three-magnet housing  2 . In (D) of  FIG. 4 , arrows express a magnetic force in a sliding-direction applied on the one-magnet housing  3  in respective positions between P 1  and P 7 . In (E) of  FIG. 4 , directions of arrows and a dotted graphic curve express a repulsive force in a direction perpendicular to the principal surface, that is, a floating force applied on the one-magnet housing  3  in respective positions between P 1  and P 7 . 
         [0017]    (D) of  FIG. 4  is substantially the same as (D) of  FIG. 3  except that sliding force is generated in P 1  (close position) and P 7  (open position) in (D) of  FIG. 4 . Sliding force in P 3  or P 5  in (D) of  FIG. 4  is smaller than that in (D) of  FIG. 3  because the magnet  21  is slid in the long magnet  8 B. 
         [0018]    When the user pushes the housing  3  against such generated sliding force so that the center position of the magnet  21  moves from P 1  (close position) to the left against rightward sliding force in P 2  and P 3 , the center position of the magnet  21  is slid to P 7  (open position) via P 5  and P 6  by leftward sliding force and held in P 7  after the center of the magnet  21  goes beyond P 4 . 
         [0019]    Accordingly, the user needs to push the housing  3  continuously up to a position corresponding to a half of the sliding distance. After the center of the magnet  21  goes beyond the half position, the housing  3  is abruptly slid by sliding force. 
         [0020]    Floating force in (E) of  FIG. 4  is as follows. Adsorbing force by which the magnets attract each other in a direction perpendicular to the principal surface is generated in P 1  (close position) and P 7  (open position). Floating force due to repulsion of the magnets in the direction perpendicular to the principal surface is generated in a range of from P 2  to P 6 . 
         [0021]    According to JP-2008-113067-A and JP-2007-288436-A, user-friendliness in sliding operation is poor because the user needs to push the housing continuously up to a position corresponding to a half of the sliding distance when the user wants to slide the housing. Moreover, because the housing is abruptly slid by sliding force after the center of the magnet goes beyond the half position, there is a problem that shock at stopping of the housing is so large that the shock has to be absorbed sufficiently. In addition, because adsorbing force is generated in a direction perpendicular to the principal surface, the user feels unsmoothness in performing sliding operation. 
       SUMMARY OF THE INVENTION 
       [0022]    According to an aspect of the present invention, there is provided a portable terminal including: a first housing; a second housing slidable in a sliding direction with respect to the first housing between an opened state and a closed state; a first magnet disposed in the first housing; a second magnet disposed in the second housing to face the first magnet in the closed state; and a third magnet disposed in the second housing to face the first magnet in the opened state, wherein an S pole of the first magnet is positioned on a side of the first housing facing the second housing, while an N pole thereof is positioned on an opposite side of the first housing, and wherein an N pole of the second magnet, an S pole of the second magnet, an S pole of the third magnet and an N pole of the third magnet are aligned as a sequence along the sliding direction. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  illustrates an appearance of a portable terminal  100  according to an embodiment. 
           [0024]      FIG. 2  illustrates an example arrangement of magnets in the portable terminal  100  according to the embodiment, as viewed from side. 
           [0025]      FIG. 3  illustrates an arrangement of magnets in JP-2008-113067-A, as viewed from side. 
           [0026]      FIG. 4  illustrates an arrangement of magnets in JP-2007-288436-A, as viewed from side. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]      FIG. 1  illustrates an appearance of a portable terminal  100  according to an embodiment. The portable terminal  100  includes a first housing  10  and a second housing  20  which are slid in a sliding direction relative to each other. The first housing  10  has a first magnet  1  provided on the inner side of the first housing  10  at one side. The second housing  20  has a second magnet  2  and a third magnet  3  which are provided on the inner side of the second housing  20  at the one side which is the same side on which the first magnet  1  is provided. 
         [0028]    These three magnets are arranged along one and the same line in the sliding direction so that magnetic force performs both assistance and holding in accordance with a user&#39;s sliding operation. 
         [0029]    Although the case where a set of the three magnets are provided on one side is exemplified, the set of the three magnets may be provided along the sliding direction at a center portion between one side and the other side. Alternatively, another set of magnets may be further provided along the sliding direction at the other side. 
         [0030]      FIG. 2  illustrates an example arrangement of the magnets in the portable terminal  100  according to the embodiment, as viewed from side. In  FIG. 2 , (A) shows a close position where a stopper (not shown) stops the first housing  10  from sliding to the right any more, (B) shows an intermediate position, and (C) shows an open position where a stopper (not shown) stops the first housing  10  from sliding to the left any more. The first housing  10  is provided with the first magnet  1 . The second housing  20  is provided with the second and third magnets  2  and  3 . 
         [0031]    In the first housing  10 , the first magnet  1  has an S pole disposed on a side facing on the second housing  20 , and an N pole disposed on an opposite side in a direction perpendicular to a principal surface. In the second housing  20 , the second and third magnets  2  and  3  are provided so that an N pole of the second magnet  2 , an S pole of the second magnet  2 , an S pole of the third magnet  3  and an N pole of the third magnet  3  are arranged as a sequence of magnetic poles along the same line in the sliding direction. That is, S poles are disposed on the inner side and N poles are disposed on the outer side. 
         [0032]    The center position of the first magnet  1  in the one-magnet first housing  10  is slid between a position P 1  (close position) and a position P 9  (open position) relative to the two-magnet second housing  20 . In (D) of  FIG. 2 , directions of arrows correspond to s magnetic force in the sliding direction applied on the one-magnet first housing  10  in respective positions between P 1  and P 9 . In (E) of  FIG. 2 , directions of arrows and a dotted graphic curve correspond to a repulsive force in a direction perpendicular to the principal surface, that is, a floating force applied on the one-magnet first housing  10  in respective positions between P 1  and P 9 . 
         [0033]    In (D) of  FIG. 2 , in P 1  (close position), the first magnet  1  is located in a center portion between the S and N poles of the second magnet  2  so that rightward sliding force to close the first housing  10  is generated based on repulsion of the S pole of the first magnet  1  and the S pole of the second magnet  2  and attraction of the S pole of the first magnet  1  and the N pole of the second magnet  2 . In P 2 , rightward force to restore the first housing  10  to P 1  (close position) is generated in the same manner as in P 1 . 
         [0034]    In P 3 , the center point of the S pole of the first magnet  1  is slightly on the left of the center point of the S pole of the second magnet  2 . And, slightly leftward sliding force is applied on the first housing  10 , while attraction of the S pole of the first magnet  1  and the N pole of the second magnet  2  remains a little. Thus, both attraction and repulsion of the magnets are cancelled by each other so that the sliding force becomes zero. 
         [0035]    In the further left position P 4 , repulsion of the S pole of the first magnet  1  and the S pole of the second magnet  2  becomes so strong that leftward sliding force is generated. 
         [0036]    In P 5  (intermediate position), sliding force is zero because the repulsive force of the first magnet  1  and the second magnet  2  and the repulsive force of the first magnet  1  and the third magnet  3  compete with each other. 
         [0037]    Sliding forces symmetrical to those in P 4 , P 3 , P 2  and P 1  (close position) are generated in P 6 , P 7 , P 8  and P 9  (open position), respectively. 
         [0038]    When the user pushes the first housing  10  against such generated sliding force so that the center position of the first magnet  1  moves from P 1  (close position) to the left against rightward sliding force in P 1  and P 2 , repulsive force against the user&#39;s operation is eliminated in P 3  earlier than the intermediate position P 5  and leftward assisting force is generated in P 4  so that movement of the center position of the first magnet  1  is assisted before P 5  (intermediate position). When the user pushes the first housing  10  to the left again against rightward sliding force in P 6 , the center position of the first magnet  1  is held in P 9  (open position) by leftward sliding force in P 8  and P 9  (open position) after it passes through P 7 . 
         [0039]    As a result, sliding of the first housing  10  is assisted without necessity of user&#39;s continuous pushing to P 5  (intermediate position). Moreover, when the center position of the first magnet  1  is held in P 9  (open position), shock can be relaxed due to sliding force in P 8  and P 9 . 
         [0040]    Floating force in (E) of  FIG. 2  is as follows. In P 1  (close position), repulsion of the S pole of the first magnet  1  and the S pole of the second magnet  2  and attraction of the S pole of the first magnet  1  and the N pole of the second magnet  2  complete with each other in a direction perpendicular to the principal surface so that floating force is substantially zero and there is no attractive force generated as a whole. Floating force in P 9  (open position) is substantially zero likewise. 
         [0041]    In each position between P 1  (close position) and P 9  (open position), floating force is generated based on repulsion of the S pole of the first magnet  1  and the S pole of the second magnet  2  and repulsion of the S pole of the first magnet  1  and the S pole of the third magnet  3 . 
         [0042]    When the user wants to slide the first housing  10 , the user may often slide the first housing  10  while not pressing an end surface of the first housing  10  but pressing the principal surface side of the first housing  10  with the user&#39;s thumb. For this reason, there is a possibility that friction between the first housing  10  and the second housing  20  will increase because of downward force perpendicular to the principal surface. The friction is however reduced by upward floating force generated in all sliding regions so that the first housing  10  can be slid smoothly. 
         [0043]    As described above, according to the embodiment, smooth motion can be obtained when the user slides the housing because assisting force based on magnets is generated in a position before a position corresponding to a half of the sliding distance. Moreover, shock due to magnets in the final sliding position can be relaxed. In addition, smooth motion can be obtained because friction in a direction perpendicular to the principal surface can be relaxed. 
         [0044]    The order of arrangement of respective magnetic poles of the magnets may be reversed. That is, the respective magnet poles of the magnets may be arranged so that the S and N poles of the first magnet  1  are put in reverse order, the S and N poles of the second magnet  2  are put in reverse order and the S and N poles of the third magnet  3  are put in reverse order. 
         [0045]    A sliding spring which has been heretofore used as a sliding assistant may be used in combination with the magnets. Consequently, the size of the spring and the number of turns of the spring can be reduced so that the size and thickness of the portable terminal can be reduced. 
         [0046]    The embodiment can be applied also to a sliding type structure in a cellular phone, a PHS, a game machine, etc. 
         [0047]    According to an aspect of the invention, there is provided a sliding mechanism using magnets in which user-friendliness in sliding operation can be improved and in which shock can be relaxed.