Abstract:
The present invention pertains to a mobile terminal charging device, and a vehicle using the same, and the objective of the present invention is to reduce user discomfort. In order to achieve this objective, the present invention moves a charging coil ( 8 ) from a charging position to a standby position by means of motors ( 28, 33 ) when charging is complete, or when charging is discontinued. The speed when the charging coil ( 8 ) is thus moved from the charging position to the standby position is lower than when the charging coil ( 8 ) is moved from the standby position to the charging position, and operating noise at the time can be minimised.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a mobile terminal charging apparatus for charging a mobile terminal such as a mobile phone, and an automobile including the mobile terminal charging apparatus. 
       BACKGROUND ART 
       [0002]    Mobile terminals such as mobile phones have been highly sophisticated, and their power consumption has been increased. 
         [0003]    Under such a circumstance, it has been desired to carry out charging at various places, including inside an automobile. In recent years, so-called non-contact charging that uses no cables has been attracting attention. 
         [0004]    The following mobile terminal charging apparatus has been proposed to meet such demands. 
         [0005]    Specifically, the mobile terminal charging apparatus includes: a main body case provided with a mobile terminal placement plate at its top surface; a charging coil movably provided in the main body case to face the bottom surface side of the mobile terminal placement plate; a driving section that moves the charging coil such that the charging coil faces the bottom surface side of the mobile terminal placement plate; and a control section connected with the driving section and the charging coil. 
         [0006]    In addition, the mobile terminal placement plate is provided with a plurality of detection coils that detect the position of a mobile terminal placed on the top surface of the mobile terminal placement plate (see, for example, PTL 1). 
       CITATION LIST 
     Patent Literature 
       [0007]    PTL 1 
         [0008]    Japanese Patent Application Laid-Open No. 2009-247194 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0009]    In the above-mentioned conventional example, when the mobile terminal is put on the top surface of the mobile terminal placement plate, the position of the mobile terminal is detected by the detection coils. The charging coil is moved to the detected position and charging can be carried out in that state, and thus the charging can be efficiently carried out. 
         [0010]    In addition, after the charging is completed, the charging coil may possibly be moved from the charging position to the standby position for the next charging. In that case, it is desirable that the movement do not make the user uncomfortable. 
         [0011]    That is, while the movement of the charging coil at the time of charging reassures the user that the charging operation is appropriately carried out, the movement of the charging coil in the state where the charging is completed or interrupted is not expected by the user and makes the user uncomfortable. 
         [0012]    When driving an automobile in particular, the driver is responsive to sound, and as such the above-mentioned unexpected operation sound is often uncomfortable. 
         [0013]    An object of the present invention is to provide a mobile terminal charging apparatus which reduces uncomfortable situations, and an automobile including the mobile terminal charging apparatus. 
       Solution to Problem 
       [0014]    A mobile terminal charging apparatus according to an embodiment of the present invention includes: a main body case including a mobile terminal placement plate disposed on a top surface of the main body case; a detection section that detects a position of a mobile terminal placed on a top surface of the mobile terminal placement plate; a charging coil movably disposed in the main body case to face a bottom surface side of the mobile terminal placement plate; a driving section that moves the charging coil; and a control section connected with the driving section and the charging coil. In the mobile terminal charging apparatus, the control section controls the driving section to move the charging coil from a standby position to a charging position when the mobile terminal is charged with the charging coil, the charging position facing the mobile terminal that is detected by the detection section; the control section controls the driving section to move the charging coil from the charging position to the standby position when the charging is completed or interrupted; and, when the charging coil is moved from the charging position to the standby position, the charging coil is moved at a velocity lower than a velocity of the charging coil that is moved from the standby position to the charging position. 
       Advantageous Effects of Invention 
       [0015]    As described, the embodiment of the present invention includes: a main body case including a mobile terminal placement plate disposed on a top surface of the main body case; a detection section that detects a position of a mobile terminal placed on a top surface of the mobile terminal placement plate; a charging coil movably disposed in the main body case to face a bottom surface side of the mobile terminal placement plate; a driving section that moves the charging coil; and a control section connected with the driving section and the charging coil. Further, in the embodiment of the present invention, the control section controls the driving section to move the charging coil from a standby position to a charging position when the mobile terminal is charged with the charging coil, the charging position facing the mobile terminal that is detected by the detection section; the control section controls the driving section to move the charging coil from the charging position to the standby position when the charging is completed or interrupted; and, when the charging coil is moved from the charging position to the standby position, the charging coil is moved at a velocity lower than a velocity of the charging coil that is moved from the standby position to the charging position. Consequently, the operation sound can be made less uncomfortable for the user. 
         [0016]    That is, in the embodiment of the present invention, when charging is completed or interrupted, the charging coil is moved by the driving section from the charging position to the standby position. When the charging coil is moved from the charging position to the standby position in this manner, the velocity of the charging coil is lower than that of the charging coil that is moved from the standby position to the charging position, and the operation sound of the charging coil that is moved from the charging position to the standby position is significantly small. Thus, the operation sound can be made less uncomfortable for the user. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0017]      FIG. 1  is a perspective view illustrating a state where a mobile terminal charging apparatus of an embodiment of the present invention is provided inside an automobile; 
           [0018]      FIG. 2  is a perspective view of the same; 
           [0019]      FIG. 3  is a perspective view of the same; 
           [0020]      FIG. 4  is a perspective view of the same in which a part is removed; 
           [0021]      FIG. 5  is a plan view of the same in which a part is removed; 
           [0022]      FIG. 6  is a partially cutout perspective view of the same; 
           [0023]      FIG. 7  is a perspective view of the same in which a part is removed; 
           [0024]      FIG. 8  is a plan view of the same in which a part is removed; 
           [0025]      FIG. 9  is a control block diagram of the same; 
           [0026]      FIG. 10  is a flowchart of an operation of the same; 
           [0027]      FIG. 11  illustrates a detection coil of the same; 
           [0028]      FIG. 12  illustrates the detection coil of the same; 
           [0029]      FIG. 13  illustrates the detection coil of the same; 
           [0030]      FIG. 14  illustrates a relationship between the detection coil and a charging coil of the same; 
           [0031]      FIG. 15  is a flowchart of an operation of the same; 
           [0032]      FIG. 16  illustrates a relationship between the detection coil and the charging coil of the same; 
           [0033]      FIG. 17  illustrates a relationship between the detection coil and the charging coil of the same; 
           [0034]      FIG. 18  illustrates a relationship between the detection coil and the charging coil of the same; 
           [0035]      FIG. 19  illustrates a state where the charging coil is moved from a standby position to a charging position of the same; 
           [0036]      FIG. 20  illustrates a state where the charging coil is moved from the charging position to the standby position of the same; and 
           [0037]      FIG. 21  is a flowchart of an operation of the same. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0038]    In the following, an embodiment of the present invention is described with reference to the accompanying drawings. 
       Embodiment 1 
       [0039]    In  FIG. 1 , wheel  3  is disposed on the front side of vehicle interior  2  of automobile  1 . 
         [0040]    In addition, electronic equipment  4  that reproduces music and images and displays car navigation images is disposed on a side of wheel  3 . 
         [0041]    Further, mobile terminal charging apparatus  5  is disposed on a lower and rear side of electronic equipment  4  of vehicle interior  2 . 
         [0042]    As illustrated in  FIG. 2  to  FIG. 6 , mobile terminal charging apparatus  5  includes box-type main body case  7  that is provided with mobile terminal placement plate  6  at its top surface, charging coil  8  that is provided in main body case  7  such that it faces the bottom surface side of the mobile terminal placement plate  6  and is movable in the horizontal direction, driving section  9  that horizontally moves charging coil  8  facing the bottom surface side of the mobile terminal placement plate  6 , and a control section ( 10  in  FIG. 9 ) that is connected with driving section  9  and the charging coil  8 . 
         [0043]    In the following, the components are described in detail. 
         [0044]    First, mobile terminal placement plate  6  is described. 
         [0045]    As illustrated in  FIG. 6 , mobile terminal placement plate  6  has a configuration in which front surface plate  11 , intermediate plate  12 , and rear surface plate  13  are stacked on one another. 
         [0046]    In addition, front surface plate  11  and rear surface plate  13  are formed of a synthetic resin, and intermediate plate  12  is formed of a ceramic. That is, a magnetic flux from charging coil  8  can pass through mobile terminal placement plate  6  toward mobile terminal  15 . 
         [0047]    In addition, position detection coil  14  illustrated in  FIG. 9  is provided on a surface of intermediate plate  12 . 
         [0048]    Position detection coil  14  detects a position where mobile terminal  15  is put on the top surface of mobile terminal placement plate  6 . 
         [0049]    In the present embodiment, position detection coil  14  is used to detect a position where mobile terminal  15  is put on the top surface of mobile terminal placement plate  6 , and then charging coil  8  is moved by driving section  9  to a charging coil position (not illustrated) of the mobile terminal  15 . 
         [0050]    Next, charging coil  8  is described. 
         [0051]    As can be seen in  FIG. 4  and  FIG. 5 , charging coil  8  is configured by repeatedly wounding a lead into an annular form, and is held such that its outer periphery side and bottom surface side are covered with holding member  16  formed of a synthetic resin. 
         [0052]    In addition, as illustrated in  FIG. 6 , support leg  17  formed of a synthetic resin is integrally formed on the bottom surface of holding member  16  to extend downward of charging coil  8 . 
         [0053]    In addition, a 0.3 mm gap is provided between the bottom surface of support leg  17  and the top surface of metal support plate  18  disposed below support leg  17 , and therefore, in a normal state, the bottom surface of support leg  17  does not make contact with the top surface of support plate  18  when charging coil  8  moves. 
         [0054]    In the above-mentioned configuration, support leg  17  is provided below charging coil  8  in the present embodiment. 
         [0055]    It is to be noted that control substrate  19  and bottom surface plate  20  of main body case  7  are disposed below support plate  18 , and supporting member  21  penetrating control substrate  19  is provided between the bottom surface of support plate  18  and the top surface of bottom surface plate  20 . 
         [0056]    Next, driving section  9  is described. 
         [0057]    As illustrated in  FIG. 4  and  FIG. 5 , driving section  9  includes X-axial drive shaft  22  and Y-axial drive shaft  23  which are engaged with holding member  16  at intermediate portions thereof except for the charging coil holding portion of holding member  16 . 
         [0058]    Specifically, holding member  16  is provided with a through hole (not illustrated) through which X-axial drive shaft  22  penetrates and through hole  24  through which Y-axial drive shaft  23  penetrates, and the through holes are crossed with a predetermined space therebetween in a vertical direction. When X-axial drive shaft  22  and Y-axial drive shaft  23  penetrate the through holes, the engaging state is established. 
         [0059]    In addition, worm wheel  25  is provided on one end side of X-axial drive shaft  22 , and gear  26  is provided at each of the one end and the other end of X-axial drive shaft  22 . 
         [0060]    Worm wheel  25  is engaged with worm  27 , and worm  27  is coupled with motor  28 . 
         [0061]    In addition, each of gears  26  on the both sides is engaged with gear plate  29 . 
         [0062]    Accordingly, when motor  28  is driven, worm  27  rotates such that worm wheel  25  moves together with X-axial drive shaft  22  in the X-axis direction, and that charging coil  8  moves in the X-axis direction. 
         [0063]    In addition, worm wheel  30  is provided on one end side of Y-axial drive shaft  23 , and gear  31  is provided at each of the one end and the other end of Y-axial drive shaft  23 . 
         [0064]    Worm wheel  30  is engaged with worm  32 , and worm  32  is coupled with motor  33 . 
         [0065]    In addition, each of gears  31  on the both sides is engaged with gear plate  34 . 
         [0066]    Accordingly, when motor  33  is driven, worm  32  rotates such that worm wheel  30  moves together with the Y-axial drive shaft  23  in the Y-axis direction, and that charging coil  8  moves in the Y-axis direction. 
         [0067]    Here, motors  28  and  33  are described in more detail. 
         [0068]    Preferably, each of motors  28  and  33  is composed of a stepping motor that performs an intermittent step operation in accordance with input pulse power. The velocity of the stepping motor is typically expressed by [pps], which is the number of pulses (steps) per second and is referred to as pulse rate, or step rate. 
         [0069]    It is to be noted that the reference numeral  35  shown in  FIG. 4  denotes a flexible wiring for energizing charging coil  8 , and an end portion of flexible wiring  35  is fixed at the side surface of support leg  17 . 
         [0070]    In addition, as illustrated in  FIG. 9 , control section  10  is connected with motor  28  and motor  33  through X-axial motor control section  36  and through Y-axial motor control section  37 , respectively. 
         [0071]    In addition, control section  10  is connected with charging coil  8  and position detection coil  14  through charging coil control section  38  and through detecting coil control section  39 , respectively. 
         [0072]    With this configuration, in the present embodiment, when the power switch is turned OFF (at S 1  in  FIG. 10 ), charging coil  8  is moved to a center of main body case  7  (hereinafter referred to as point A) (at S 2  in  FIG. 10 ) as illustrated in  FIG. 4  to  FIG. 6 , and thereafter the power source is turned OFF (at S 3  in  FIG. 10 ). 
         [0073]    That is, when mobile terminal  15  is not put on mobile terminal placement plate  6  of main body case  7  as illustrated in  FIG. 2 , mobile terminal placement plate  6  is exposed to vehicle interior  2  as illustrated in  FIG. 1 . 
         [0074]    Accordingly, mobile terminal placement plate  6  may be mistakenly touched with hands, and in that case, overload is exerted on mobile terminal placement plate  6 . 
         [0075]    In view of this, in the present embodiment, charging coil  8  is moved to a center portion of main body case  7  as illustrated in  FIG. 4  to  FIG. 6  to bear the above-described overload with charging coil  8 , holding member  16 , support leg  17 , and support plate  18 . 
         [0076]    Specifically, in the state where an overload is exerted on mobile terminal placement plate  6 , mobile terminal placement plate  6  is slightly curved downward. In this state, charging coil  8 , holding member  16 , and support leg  17  also move downward, and the bottom surface of support leg  17  makes contact with the top surface of support plate  18 . 
         [0077]    As a result, the overload is borne with support plate  18  through mobile terminal placement plate  6 , charging coil  8 , holding member  16  and support leg  17 , and thus it is possible to limit a damage of mobile terminal placement plate  6  and charging coil  8 . 
         [0078]    It is to be noted that, in the present embodiment, the bottom surface side of support plate  18  is supported with bottom surface plate  20  of main body case  7  through supporting member  21  in order to increase the strength against the overload. 
         [0079]    In addition, when such an overload is removed, mobile terminal placement plate  6  elastically returns upward, and charging coil  8  and holding member  16  upwardly return with the elastic return of X-axial drive shaft  22  and Y-axial drive shaft  23 , thus establishing the state where a gap is interposed between the bottom surface of support leg  17  and the top surface of support plate  18 . 
         [0080]    In this manner, the movement of charging coil  8  described below is not impeded. 
         [0081]    In addition, at the time of charging mobile terminal  15 , first, the power switch is turned ON (at S 4  in  FIG. 10 ), and mobile terminal  15  is put on the top surface of mobile terminal placement plate  6 . 
         [0082]    Also in this state, first, control section  10  determines whether charging coil  8  is present at point A in the present embodiment (at S 5  in  FIG. 10 ). 
         [0083]    This determination can be carried out based on the driving amount of the motors  28  and  33  that is stored in X-axial motor control section  36  and Y-axial motor control section  37 . 
         [0084]    When it is determined that charging coil  8  is not present at point A, control section  10  moves charging coil  8  to point A (at S 6  in  FIG. 10 ), and brings charging coil  8  into a charging standby state at point A (at S 7  in  FIG. 10 ). 
         [0085]    Next, control section  10  uses position detection coil  14  to detect the position where mobile terminal  15  is put on the top surface of mobile terminal placement plate  6  (at S 8  and S 9  in  FIG. 10 ). 
         [0086]    Actually, the position where mobile terminal  15  is put is the position of a mobile charging coil ( 15   a  in  FIG. 16 ) incorporated in mobile terminal  15 . 
         [0087]    Thereafter, control section  10  drives motors  28  and  33  through X-axial motor control section  36  and Y-axial motor control section  37 , and moves charging coil  8  to the position of the mobile charging coil ( 15   a  in  FIG. 16 ) of mobile terminal  15  (at S 10  in  FIG. 10 ). Then, control section  10  starts charging through charging coil control section  38  (at S 11  and S 12  in  FIG. 10 ). 
         [0088]    In addition, during the charging, an operation same as that disclosed in PTL 1 (Japanese Patent Application Laid-Open No. 2009-247194) is carried out. Specifically, through communication with a terminal charging coil, it is determined whether power transmission is allowed (or the charging has been completed) (at S 13  in  FIG. 10 ), and when it is determined that the power transmission is not allowed (full charge), control section  10  stops the power transmission (at S 14  in  FIG. 10 ). 
         [0089]    In addition, when the above-mentioned charging operation is completed, control section  10  determines whether charging coil  8  is present at point A (at S 15  in  FIG. 10 ), and thereafter, brings back charging coil  8  to point A (at S 6  in  FIG. 10 ). 
         [0090]    This determination can be carried out based on the driving amount of motors  28  and  33  that is stored in X-axial motor control section  36  and Y-axial motor control section  37 . 
         [0091]    It is to be noted that the following operation is executed when control section  10  cannot bring back charging coil  8  to point A, for example, when the position calculated from the driving amount of motors  28  and  33  that is stored in X-axial motor control section  36  and Y-axial motor control section  37  and the actual position measured by position detection coil  14  are shifted due to an impact during the operation. 
         [0092]    Specifically, control section  10  drives motors  28  and  33  through X-axial motor control section  36  and Y-axial motor control section  37  to move charging coil  8  to a corner in main body case  7 . 
         [0093]    Switches  41  and  42  are provided at the corner portion, and when charging coil  8  is moved to the corner in main body case  7 , switches  41  and  42  are activated, and based on the activation, control section  10  determines that charging coil  8  is moved to a position corresponding to the initial value. 
         [0094]    In this state, the amount of operation of motors  28  and  33  by X-axial motor control section  36  and Y-axial motor control section  37  is set to the initial value, and a position control is again performed from this position. 
         [0095]    As described, in the present embodiment, control section  10  brings back charging coil  8  to point A at the time when the charging operation is completed. This configuration is described below in more detail. 
         [0096]    The point A is located at a center portion of main body case  7  as described above, and the relationship between the point A and position detection coil  14  is as follows. 
         [0097]    First, position detection coil  14  is described. 
         [0098]    Position detection coil  14  is provided in ceramic intermediate plate  12  of mobile terminal placement plate  6 . Specifically, as illustrated in  FIG. 11 , position detection coil  14 A that detects the X-axial position is provided on the front side of intermediate plate  12 , and position detection coil  14 B that detects Y-axial position is provided on the rear side of intermediate plate  12 . 
         [0099]    It is to be noted that position detection coil  14 A and position detection coil  14 B are orthogonal to each other through ceramic intermediate plate  12  of mobile terminal placement plate  6 . 
         [0100]    As can be seen in  FIG. 11  and  FIG. 12 , position detection coil  14 A that detects the X-axial position detect is composed of a plurality of position detection coils  14 Aa,  14 Ab,  14 Ac and  14 Ad that are disposed along the longitudinal direction of ceramic intermediate plate  12  of mobile terminal placement plate  6  with predetermined intervals therebetween. 
         [0101]    As illustrated in  FIG. 12 , each of position detection coils  14 Aa,  14 Ab,  14 Ac and  14 Ad has a rectangular loop form, and is sifted by one-third of its short side. 
         [0102]    That is, in  FIG. 12 , the lower side of position detection coil  14 Aa and the upper side of position detection coil  14 Ad overlap each other. 
         [0103]    In the above-mentioned state, position detection coils  14 Aa,  14 Ab,  14 Ac and  14 Ad are regularly disposed in the longitudinal direction of ceramic intermediate plate  12  of mobile terminal placement plate  6 . 
         [0104]    In contrast, as can be seen in  FIG. 11  and  FIG. 13 , position detection coil  14 B that detects the Y-axial position is composed of a plurality of position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd that are disposed along the short direction of ceramic intermediate plate  12  of mobile terminal placement plate  6  with predetermined intervals therebetween. 
         [0105]    As illustrated in  FIG. 13 , each of position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd has a rectangular loop form, and is sifted by one-third of its short side. 
         [0106]    That is, in  FIG. 13 , the right side of position detection coil  14 Ba and the left side of position detection coil  14 Bd overlap each other. 
         [0107]    In the above-mentioned state, position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd are regularly disposed in the short direction of ceramic intermediate plate  12  of mobile terminal placement plate  6 . 
         [0108]    Next, with reference to  FIG. 14 , the relationship among position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd, and point A that is the center portion of main body case  7  is described. 
         [0109]    In  FIG. 14 , position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd are shifted also in the vertical direction for differentiation, but actually, position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd are disposed as illustrated in  FIG. 13 . 
         [0110]    In  FIG. 14 , “a” is a center line passing through the center of the short side of position detection coil  14 Ba, “b” a center line passing through the center of the short side of position detection coil  14 Ba, “c” a center line passing through the center of the short side of position detection coil  14 Ba, and “d” a center line passing through the center of the short side of position detection coil  14 Ba. 
         [0111]    Here, it is important that the center point of charging coil  8  in a standby state at the point A do not overlap any of the center lines a, b, c and d of position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd as illustrated in  FIG. 14 . 
         [0112]    That is, after the charging is completed, charging coil  8  is moved to a position that does not overlap any of the center lines a, b, c and d of position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd (a part apart from the center lines a, b, c and d of position detection coils  14 Ba,  14 Bb,  14 Bc and  14 B) such that charging coil  8  is brought into a stand-by state at this position A (at S 2  or S 7  in  FIG. 10 ). 
         [0113]    It is to be noted that, in the present embodiment, the detection whether mobile terminal  15  is put on the top surface of mobile terminal placement plate  6  (at S 8  in  FIG. 10 ) is performed on the side of position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd, and therefore a position that does not overlap the center lines a, b, c and d of position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd is set as position A at which charging coil  8  is brought into a stand-by state. 
         [0114]    As a matter of course, the detection whether mobile terminal  15  is put on the top surface of mobile terminal placement plate  6  (at S 8  in  FIG. 10 ) may be performed on the side of position detection coils  14 Aa,  14 Ab,  14 Ac, and  14 Ad, and in that case, a position that does not overlap the center lines a, b, c and d of position detection coils  14 Aa,  14 Ab,  14 Ac and  14 Ad is set as position A at which charging coil  8  is brought into a stand-by state. 
         [0115]    On the basis of the above-mentioned configuration, the operation is described in more detail. When power switch  40  is turned ON to charge mobile terminal  15  (at S 4  in  FIG. 10 ), control section  10  determines whether charging coil  8  is present at point A as described above (at S 5  in  FIG. 10  and  FIG. 15 ). 
         [0116]    This determination can be carried out based on the driving amount of motors  28  and  33  that is stored in X-axial motor control section  36  and Y-axial motor control section  37 . 
         [0117]    When it is determined that charging coil  8  is not present at point A, control section  10  moves charging coil  8  to point A (at S 6  in  FIG. 10  and  FIG. 15 ), and brings charging coil  8  into a charging standby state at point A (at S 7  in  FIG. 10  and  FIG. 15 ). 
         [0118]    Next, control section  10  detects the position where mobile terminal  15  is put on the top surface of mobile terminal placement plate  6  with use of position detection coil  14  (at S 8  and S 9  in  FIG. 10  and  FIG. 15 ). 
         [0119]    Actually, the position where mobile terminal  15  is put is the position of the mobile charging coil ( 15   a  in  FIG. 16 ) incorporated in mobile terminal  15 . 
         [0120]    This configuration is described below in detail with reference to  FIG. 14  and  FIG. 15 . When determining the position where mobile terminal  15  is put on the top surface of mobile terminal placement plate  6  with use of position detection coil  14 , a 1 MHz pulse signal is sequentially suppled to position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd from detecting coil control section  39  illustrated in  FIG. 9  (at S 81  in  FIG. 15 ). Control section  10  determines the position where mobile terminal  15  is put on the top surface of mobile terminal placement plate  6  (at S 82  and S 83  in  FIG. 15 ) based on whether an echo signal comes from the mobile charging coil ( 15   a  in  FIG. 16 ) of mobile terminal  15  in response to the 1 MHz pulse signal. 
         [0121]    It is to be noted that the echo signal caught at this time by position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd is temporarily stored in memory  10   a  illustrated in  FIG. 9 . 
         [0122]    It is well known that the mobile charging coil ( 15   a  in  FIG. 16 ) of mobile terminal  15  resonates at 1 MHz before charging. As such, the mobile charging coil outputs a large echo signal when the 1 MHz pulse signal is sequentially output to position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd, and then position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd catch the echo signal. In this manner, the position where mobile terminal  15  is put on the top surface of mobile terminal placement plate  6  is detected. 
         [0123]      FIG. 16  illustrates a state where the mobile charging coil  15   a  of mobile terminal  15  is put on the top surface of mobile terminal placement plate  6  at a position on the center line b of position detection coil  14 Bb, and  FIG. 16  suggests that the echo signal caught at position detection coil  14 Bb has the largest value among position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd. 
         [0124]    In contrast,  FIG. 17  illustrates a state where the mobile charging coil  15   a  of mobile terminal  15  is put on the top surface of mobile terminal placement plate  6  at a position between center lines b and c of position detection coils  14 Bb and  14 Bc, and  FIG. 17  suggests that the echo signals caught at position detection coils  14 Bb and  14 Bc are larger than those of position detection coils  14 Ba and  14 Bd but are smaller than the echo signal of  FIG. 16 . 
         [0125]    In addition, depending on the type or the state (for example, a cover is provided on the rear surface, or a seal is stuck on the rear surface) of mobile terminal  15 , the echo signal from mobile charging coil  15   a  of mobile terminal  15  may be as small as that of  FIG. 17 . The determination level of the echo signal is set at a low level such that the position where mobile terminal  15  is put on the top surface of mobile terminal placement plate  6  can be detected even in the above-mentioned cases. 
         [0126]    However, when the determination level of the echo signal is set at a low level, malfunction may be caused by the echo signal from charging coil  8 . 
         [0127]      FIG. 18  illustrates a case where the standby position A of charging coil  8  is located under center line b of position detection coil  14 Bb, for example.  FIG. 18  suggests that, in this case, the echo signal from charging coil  8  caught at position detection coil  14 Bb has a high value and is largest among position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd. 
         [0128]    In such a state, it is impossible to determine whether the echo signal caught at position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd is from mobile charging coil  15   a  or charging coil  8 , and consequently, malfunction may be caused in the subsequent operations. 
         [0129]    That is, as described above, depending on the position of mobile terminal  15  put on the top surface of mobile terminal placement plate  6 , the type of mobile terminal  15 , and the state (for example, a cover is provided on the rear surface, or a seal is stuck on the rear surface) of mobile terminal  15 , the echo signal from the mobile charging coil  15   a  of mobile terminal  15  may be small as in  FIG. 17 . The determination level of the echo signal is set at a low level such that the position of mobile terminal  15  put on the top surface of mobile terminal placement plate  6  can be detected even in the above-mentioned cases. 
         [0130]    However, when the determination level is set at a low level in this manner, control section  10  determines that mobile terminal  15  is put on the top surface of mobile terminal placement plate  6  and executes the subsequent operations even when mobile terminal  15  is not put on the top surface of mobile terminal placement plate  6  in the case where the level of the echo signal from charging coil  8  is high as in  FIG. 18 . 
         [0131]    Malfunction may be caused in the above-mentioned manner, and in the present embodiment, to prevent the malfunction, the position A where charging coil  8  is brought into the stand-by state is set to a position that does not overlap any of the center lines a, b, c and d of position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd (a part apart from the center lines a, b, c and d of position detection coils  14 Ba,  14 Bb,  14 Bc and  14 B) after the charging is completed as described above. 
         [0132]    As a result, as illustrated in  FIG. 14 , the echo signal from charging coil  8  caught at position detection coils  14 Ba,  14 Bb,  14 Bc and  14 B may be set to a small value (or may be set to a value sufficiently smaller than that of  FIG. 17 ). 
         [0133]    Therefore, whether mobile terminal  15  is put on the top surface of mobile terminal placement plate  6  is determined without error, and malfunction is prevented from being caused in the subsequent stages. 
         [0134]    Then when it is determined that mobile terminal  15  is put on the top surface of mobile terminal placement plate  6 , control section  10  controls detecting coil control section  39  to supply a pulse signal to position detection coils  14 Aa,  14 Ab,  14 Ac and  14 Ad and position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd, thereby specifying mobile charging coil  15   a  of mobile terminal  15  (at S 9  in  FIG. 15 ). 
         [0135]    When the position of mobile charging coil  15   a  of mobile terminal  15  has been successfully specified, control section  10  drives motors  28  and  33  through X-axial motor control section  36  and Y-axial motor control section  37 , and moves charging coil  8  to the position of mobile charging coil  15   a  of the detected mobile terminal  15  (at S 10  in  FIG. 10  and  FIG. 15 ), and thereafter, starts charging through charging coil control section  38  (at S 11  and S 12  in  FIG. 10 ). 
         [0136]    Next, the most outstanding feature of the present embodiment is described with reference to  FIG. 19  to  FIG. 21 . 
         [0137]    In the present embodiment, as described above, when the power switch is turned OFF (at S 1  in  FIG. 10 ), charging coil  8  is moved to the center (standby position, hereinafter referred to as point A) of main body case  7  as illustrated in  FIG. 4  to  FIG. 6  (at S 2  in  FIG. 10 ), and thereafter the power source is turned OFF (at S 3  in  FIG. 10 ). 
         [0138]    In addition, also during the charging, an operation same as that disclosed in PTL 1 (Japanese Patent Application Laid-Open No. 2009-247194) is carried out to determine whether power transmission is allowed (charging is completed) (at S 13  in  FIG. 10 ). When it is determined that power transmission is not allowed (full charge), control section  10  stops the power transmission (at S 14  in  FIG. 10 ). 
         [0139]    When the above-mentioned charging operation is completed, control section  10  determines whether charging coil  8  is present at point A (at S 15  in  FIG. 10 ), and thereafter control section  10  brings back charging coil  8  to point A (at S 6  in  FIG. 10 ). 
         [0140]    In addition, even during the charging of mobile terminal  15 , when mobile terminal  15  is put off from mobile terminal placement plate  6 , it is determined whether power transmission is allowed (charging is completed) (at S 13  in  FIG. 10 ). Also in this case, control section  10  stops the power transmission (at S 14  in  FIG. 10 ), and then determines whether charging coil  8  is present at point A (at S 15  in  FIG. 10 ), and thereafter control section  10  brings back charging coil  8  to point A (at S 6  in  FIG. 10 ). 
         [0141]    That is, in the present embodiment, when the charging is completed, charging coil  8  is moved to position A (standby position) and brought into a standby state. 
         [0142]    To be more specific, a position that does not overlap any of the center lines a, b, c and d of position detection coils  14 Ba,  14 Bb,  14 Bc and  14 Bd (a part apart from the center lines a, b, c and d of position detection coils  14 Ba,  14 Bb,  14 Bc and  14 B) is set to the standby position of charging coil  8  (position A), and after the charging is completed, charging coil  8  is moved to position A and the power source is turned OFF. 
         [0143]    Since the present embodiment has the above-mentioned feature, it is possible to prevent erroneous determination that mobile terminal  15  is put on the top surface of mobile terminal placement plate  6  when mobile terminal  15  is not put on the top surface of mobile terminal placement plate  6  as described above, and as a result, malfunction is prevented from being caused in the subsequent stages. 
         [0144]    In addition, even when mobile terminal placement plate  6  is mistakenly touched with hands and an overload is exerted on mobile terminal placement plate  6 , charging coil  8  is moved to position A (for example, a center portion) of main body case  7  as illustrated in  FIG. 4  to  FIG. 6 , thereby bearing the overload with charging coil  8 , holding member  16 , support leg  17 , and support plate  18 . 
         [0145]    Accordingly, the overload can be borne with support plate  18  through mobile terminal placement plate  6 , charging coil  8 , holding member  16 , and support leg  17 , and thus it is possible to limit a damage of mobile terminal placement plate  6  and charging coil  8 . 
         [0146]    While charging coil  8  is brought back to a standby position (position A) when the charging operation is completed or interrupted in the present embodiment as described above, further improvement is desired in the operation at the time of the interruption of charging, for example. 
         [0147]    For example, when mobile terminal  15  which is being charged is put off from the top surface of mobile terminal placement plate  6  during the driving of automobile  1 , control section  10  terminates the charging operation (at S 14  in  FIG. 10 ), and then determines whether charging coil  8  is present at point A (at S 15  in  FIG. 10 ). Thereafter, control section  10  brings back charging coil  8  to point A (at S 6  in  FIG. 10 ). 
         [0148]    At this time, when motor  28  for X-axial drive shaft  22  is driven to bring back charging coil  8  to point A, worm  27 , worm wheel  25 , and gear  26  also quickly move. 
         [0149]    In addition, when motor  33  for Y-axial drive shaft  23  is driven to bring back charging coil  8  to point A, worm  32 , worm wheel  30 , and gear  31  also quickly move. 
         [0150]    Here, a problem of operation sound arises when motor  28 , worm  27 , worm wheel  25 , and gear  26  for X-axial drive shaft  22 , and motor  33 , worm  32 , worm wheel  30  and gear  31  for Y-axial drive shaft  23  move in the case where mobile terminal  15  is put off from the top surface of mobile terminal placement plate  6  as described above. 
         [0151]    Specifically, in the case where mobile terminal  15  is put on mobile terminal placement plate  6  to charge mobile terminal  15 , the operation sound for moving charging coil  8  to the place where mobile terminal  15  is put reassures the user that charging coil  8  is moving for the charging operation (charging operation is normally activated). 
         [0152]    However, in the case where charging is stopped, when the operation sound is generated even when charging is stopped, the user may be confused by the sound. When driving automobile  1  in particular, the driver is responsive to sound, and therefore it is desirable to reduce the operation sound as much as possible. 
         [0153]    In view of this, in the present embodiment, in the case where charging is stopped or interrupted, the operation sound caused by the operation for bringing back charging coil  8  to point A is reduced. 
         [0154]    To be more specific, as illustrated in  FIG. 20 , in the case where charging is stopped or interrupted, the rotational frequency (or the pulse rate, when stepping motors are used) of at least one of motors  28  and  33  used for bringing back charging coil  8  to point A is considerably reduced. This configuration is described in detail below. 
         [0155]      FIG. 19  shows the velocity of motors  28  and  33  at the time when control section  10  moves charging coil  8  to a position of the mobile charging coil ( 15   a  in  FIG. 16 ) of mobile terminal  15  for the purpose of charging (at S 10  in  FIG. 10 ). 
         [0156]    First, motors  28  and  33  rise at 10 mm/1 sec (“a” in  FIG. 19 ), and then the velocity is increased (“b” in  FIG. 19 ), and thereafter, motors  28  and  33  are stably driven at a velocity of 60 mm/1 sec (“c” in  FIG. 19 ). 
         [0157]    That is, when charging coil  8  is moved to a position of the mobile charging coil ( 15   a  in  FIG. 16 ) of mobile terminal  15  (at S 10  in  FIG. 10 ), charging coil  8  is moved to the position in a short time as much as possible so that charging is quickly started. 
         [0158]    At this time, control section  10  determines whether the movement of charging coil  8  is a movement to the standby position or a movement to the charging position (at S 1  in  FIG. 21 ). When the movement is a movement to the charging position, control section  10  moves charging coil  8  in accordance with a velocity table ( FIG. 19 ) stored in memory  10   a  (at S 2  and S 3  in  FIG. 21 ). 
         [0159]    In contrast, in the case where the charging is stopped or interrupted, the rotational frequency of motors  28  and  33  is considerably reduced as illustrated in  FIG. 20  at the time when charging coil  8  is brought back to point A. 
         [0160]    To be more specific, when charging coil  8  is brought back to point A in the case where charging is stopped or interrupted, the rotational frequency of motors  28  and  33  is kept in a substantially constant state at 4 mm/1 sec (“d” in  FIG. 20 ) from activation to stopping, as illustrated in  FIG. 20 . 
         [0161]    That is, at this time, motors  28  and  33  are driven at a velocity lower than the velocity of the activation (“a” in  FIG. 19 ), and, as a matter of course, lower than the velocity of the stable driving (“c” in  FIG. 19 ) of the above-mentioned case where charging coil  8  is moved to a position of the mobile charging coil ( 15   a  in  FIG. 16 ) of mobile terminal  15 . 
         [0162]    At this time, control section  10  determines whether the movement of charging coil  8  is a movement to the standby position or a movement to the charging position (at S 1  in  FIG. 21 ), and moves charging coil  8  in accordance with the velocity table ( FIG. 20 ) stored in memory  10   a  (at S 3  and S 4  in  FIG. 21 ) when the movement is a movement to the standby position. 
         [0163]    With this configuration, the operation sound caused by the operation of motor  28 , worm  27 , worm wheel  25 , and gear  26  for X-axial drive shaft  22 , and motor  33 , worm  32 , worm wheel  30  and gear  31  for Y-axial drive shaft  23  is significantly small, and thus the operation sound does not make the user uncomfortable. 
         [0164]    Further, a case where motors  28  and  33  are stepping motors is described in detail. 
         [0165]    It is known that, as the characteristics of the human ear, the human ear is sensitive to some frequencies, but is not sensitive to the other frequencies. According to Fletcher-Munson curve that is widely known to represent the characteristics of the human ear, as the frequency decreases, the sensitivity of the human ear decreases in the frequency ranges lower than about 1 kHz. 
         [0166]    In view of this, in the movement of charging coil  8  of the present embodiment, when the pulse rate of stepping motor falls within the frequency range that is lower than about 1 kHz, the lower the frequency, the smaller the operation sound, and thus the operation sound does not make the user uncomfortable. 
         [0167]    In addition, the operation sound caused by the operation of motor  28 , worm  27 , worm wheel  25 , and gear  26  for X-axial drive shaft  22 , and motor  33 , worm  32 , worm wheel  30  and gear  31  for Y-axial drive shaft  23  is large at a specific resonance point that is determined by main body case  7 , mobile terminal placement plate  6  and the like of mobile terminal charging apparatus  5 . 
         [0168]    Accordingly, when the pulse rate of the stepping motor in the stable operation is set to a low frequency, for example, to 40 Hz, almost no specific resonance point exists before reaching 40 Hz or in the range of 0 to 40 Hz. Also in this manner, the operation sound caused by driving motors  28  and  33  can be made less uncomfortable for the user. 
         [0169]    In particular, the driver is sensitive to sound when driving automobile  1 , and therefore the configuration in which the operation sound is small is advantageous. 
         [0170]    In addition, although the time for bringing back charging coil  8  to point A is lengthened when motors  28  and  33  are driven at a low velocity, this causes no problem since charging is stopped or interrupted in that case. 
         [0171]    This application is entitled to and claims the benefit of Japanese Patent Application No. 2013-114994 dated May 31, 2013, the disclosure of which including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
       INDUSTRIAL APPLICABILITY 
       [0172]    As has been described, in the present invention, the charging coil is moved by the driving section from the charging position to the standby position at the time of completion of charging or interruption of charging, and as described, the charging coil is moved from the charging position to the standby position at a velocity lower than that of the movement of the charging coil from the standby position to the charging position. Thus, the operation sound at this time is significantly small and less uncomfortable for the user. 
         [0173]    Therefore, application of the present invention to in-vehicle and home-use mobile terminal charging apparatuses is promising. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           1  Automobile 
           2  Vehicle interior 
           3  Wheel 
           4  Electronic equipment 
           5  Mobile terminal charging apparatus 
           6  Mobile terminal placement plate 
           7  Main body case 
           8  Charging coil 
           9  Driving section 
           10  Control section 
           10   a  Memory 
           11  Surface plate 
           12  Intermediate plate 
           13  Rear surface plate 
           14  Position detection coil 
           14 A,  14 Aa,  14 Ab,  14 Ac,  14 Ad,  14 B,  14 Ba,  14 Bb,  14 Bc,  14 Bd Position detection coil 
           15  Mobile terminal 
           15   a  Mobile charging coil 
           16  Holding member 
           17  Support leg 
           18  Support plate 
           19  Control substrate 
           20  Bottom surface plate 
           21  Supporting member 
           22  X-axial drive shaft 
           23  Y-axial drive shaft 
           24  Through hole 
           25  Worm wheel 
           26  Gear 
           27  Worm 
           28  Motor 
           29  Gear plate 
           30  Worm wheel 
           31  Gear 
           32  Worm 
           33  Motor 
           34  Gear plate 
           35  Flexible wiring 
           36  X-axial motor control section 
           37  Y-axial motor control section 
           38  Charging coil control section 
           39  Detecting coil control section 
           41  Switch 
           42  Switch