Abstract:
A lens holder driving device is provided with a lens holder, a securing part including a base member, a drive mechanism, and a position detection unit. The drive mechanism includes a yoke that is provided to stand on the base member. The position detection unit includes a sensor magnet mounted to the outer peripheral surface of the lens holder, and a magnetic detection element provided in the securing part. The yoke is provided with a tube-shaped external cylinder part, and the external cylinder part includes a plurality of plate sections each having a cutout section. The lens holder driving device includes a foreign matter entry prevention member that prevents foreign matter from getting inside from the cutout sections of the plate sections.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a lens holder driving device, and particularly relates to a lens holder driving device and a camera-equipped mobile terminal in which a lens holder (movable part) to which a lens barrel can be attached can move in a light axis direction of a lens. 
       BACKGROUND ART 
       [0002]    A small-sized mobile camera is installed in a camera-equipped mobile terminal. In this small-sized mobile camera, an auto focus (AF) lens holder driving device is used. VCM systems using a voice coil motor (VCM) are known as a driving mechanism (actuator) used for the above-mentioned AF lens holder driving device. An AF lens holder driving device of the VCM type includes a magnetic circuit composed of a driving coil, a yoke and a permanent magnet as a driving mechanism (actuator). The driving mechanism of the VCM type is roughly categorized into the driving mechanism of “moving coil type” and the driving mechanism of “moving magnet type.” 
         [0003]    An AF lens holder driving device of the VCM type employs a spring member (elastic member) that supports a columnar movable part including a lens (a lens and a lens holder) such that the movable part is displaceable in the light axis direction (center axis direction) in a state where the position of the movable part in the radial direction with respect to the fixing part is set. It is to be noted that the movable part is also referred to as moving body, movable body, or lens fixing body, and the fixing part is also referred to as fixing member, supporting body, housing, or fixing body. The above-mentioned driving mechanism is provided in the movable part (moving body) and the fixing part (fixing member; supporting body). 
         [0004]    As the above-mentioned spring member (elastic member), in general, a pair of leaf springs which are provided on the both sides in the light axis direction of a lens holder (columnar movable part; moving body) that holds a lens assembly (lens barrel) are used. The pair of leaf springs supports the lens holder (columnar movable part; moving body) such that the lens holder (columnar movable part; moving body) is displaceable in the light axis direction in a state where the position in the radial direction of the lens holder is set with respect to the housing (cylindrical fixing part; fixing member; supporting body) disposed at the periphery thereof. One of the pair of leaf springs is referred to as upper leaf spring, and the other is referred to as lower leaf spring. 
         [0005]    It is to be noted that the upper leaf spring is also referred to as front spring or front spring member, and the lower leaf spring is also referred to as rear spring or rear spring member. 
         [0006]    With the above-mentioned configuration, in an AF lens holder driving device of the VCM type, the restoration force (biasing force) of the leaf spring (spring member) and the thrust (driving force) of the driving mechanism are balanced, and the movable part (moving body) is moved to a predetermined position (target position) in the light axis direction. In the AF lens holder driving device of the VCM type having such a configuration, the movable part (moving body) is supported with the leaf spring (spring member) with respect to the fixing part (fixing member; housing; supporting body), and therefore the movable part (moving body) is vibrated more than necessary by driving of the movable part (moving body), or by vibration, impact and the like from the outside. 
         [0007]    In view of this, a position detection part (position detection mechanism; position detection means) is provided to the lens holder driving device to control (adjust) the position of the movable part by feedback control. Conventionally, various position detection parts have been proposed. 
         [0008]    For example, PTL 1 discloses a lens driving device that performs hand shake correction by utilizing a position detection mechanism using a Hall device sensor magnet and a Hall device sensor. The lens driving device disclosed in PTL 1 includes a cylindrical lens supporting body, an annular yoke, and a plurality of driving magnets. The cylindrical lens supporting body extends in the longitudinal direction and the coil is placed on the outer periphery side. The yoke is placed on the outside of the lens supporting body in the radial direction. The driving magnets are respectively placed at positions on the inside of the external peripheral wall of the annular peripheral wall of the yoke and the outside of the coil in the radial direction with a predetermined distance from the coil. In addition, the driving magnets are placed with a predetermined distance from the adjacent driving coil in the circumferential direction of the yoke. 
         [0009]    In PTL 1, the Hall device sensor magnet is placed at the lens supporting body at a position between adjacent two driving magnets in the circumferential direction of the yoke in the driving magnets. The Hall device sensor is placed to a base to which the yoke and the lens supporting body are installed. A cutout part is formed in the driving magnet at the side surface opposite to the adjacent driving magnet. 
         [0010]    PTL 2 discloses an image pickup device including an actuator and a position detection part. The actuator is composed of a coil attached on a driven surface of a movement cylindrical body that holds a plurality of lenses, a magnet opposite to the coil, and a yoke disposed at the periphery of the magnet. The position detection part is composed of one Hall device magnet attached on the movement cylindrical body, and a Hall device provided on an assembly housing side opposite to the movement cylindrical body and configured to detect the magnetic force of the Hall device magnet to perform position detection. 
         [0011]    PTL 3 discloses a lens driving device including an actuator and a position detection means. The actuator includes a coil body fixed at the outer periphery of a lens supporting body that supports a lens at the inner periphery, a yoke that movably supports the lens supporting body, and four driving magnets fixed at corner portions of the outer periphery side wall of the yoke. The inner periphery side of each driving magnet has an arc-like shape extending along the outer peripheral surface of the coil. 
         [0012]    In addition, in the third embodiment in PTL 3, the position detection means that detects the position of the lens supporting body with respect to the fixing body in the X direction, the Y direction and the Z direction is composed of a X-direction position detection magnet, a Y-direction position detection magnet, and a Z-direction position detection magnet disposed on the side surface of the lens supporting body, and, a X-direction position detection device, a Y-direction position detection device, and a Z-direction position detection device disposed on the external surface of the lens driving device so as to be respectively opposite to the direction position detection magnets. The circuit board in which the position detection devices are installed are provided on the outer periphery side of the lens driving device. 
       CITATION LIST 
     Patent Literature 
     PTL 1 
     Japanese Patent Application Laid-Open No. 2013-33179 
     PTL 2 
     Japanese Patent Application Laid-Open No. 2007-121850 (FIG. 3, [0023] and [0024]) 
     PTL 3 
     Japanese Patent Application Laid-Open No. 2012-177753 (FIG. 9 to FIG. 14, [0069]) 
     SUMMARY OF INVENTION 
     Technical Problem 
       [0013]    The position detection mechanism disclosed in PTL 1 detects the position in the X axis direction and the Y-axis direction orthogonal to the optical axis (Z axis) of the lens supporting body, not the position in the light axis direction (the Z-axis direction) of the lens supporting body. That is, with the configuration of the position detection mechanism disclosed in PTL 1, the position in the light axis direction (the Z-axis direction) of the lens supporting body cannot be detected. 
         [0014]    In the position detection part disclosed in PTL 2, only one Hall device magnet is attached to the movement cylindrical body, and consequently the gravity center of the moving body (the lenses, the movement cylindrical body, the coil, and the Hall device magnet) is shifted from the optical axis. As a result, with an image pickup device including the position detection part disclosed in PTL 2, it is difficult to stably drive the moving body with a good balance. 
         [0015]    In the lens driving device disclosed in PTL 3, the circuit board in which the position detection device is installed is provided on the outer periphery side of the lens driving device, and consequently foreign matter such as dust may possibly intrude into the lens driving device through the gap. 
         [0016]    Accordingly, an object of the present invention is to provide a lens holder driving device having an enclosed structure which can prevent intrusion of foreign matter such as dust. 
         [0017]    Other objects of the present invention will be apparent from the following descriptions. 
       Solution to Problem 
       [0018]    In an exemplary mode of the present invention, a lens holder driving device includes: a lens holder to which a lens barrel is attachable; a fixing part disposed at an outer periphery of the lens holder; a driving mechanism for driving the lens holder in a direction of an optical axis of a lens; and a position detection part configured to detect a position of the lens holder in the direction of the optical axis. The fixing part includes a base member disposed on a lower side of the lens holder. The driving mechanism includes a yoke uprightly provided on the base member. The position detection part includes a sensor magnet attached on a corresponding outer peripheral surface of the lens holder in a direction orthogonal to the optical axis, and a magnetic detection device provided to the fixing part such that the magnetic detection device is opposite to the sensor magnet. The yoke includes an outer cylinder part having a cylindrical shape, and the outer cylinder part includes a plurality of plate parts which are opposite to each other in the direction orthogonal to the optical axis, the plate parts having cutout parts at positions opposite to the sensor magnet. The lens holder driving device includes a foreign matter intrusion prevention member configured to prevent intrusion of foreign matters from the cutout part of the plate part. 
       Advantageous Effects of Invention 
       [0019]    According to the present invention, intrusion of foreign matter such as dust can be prevented. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0020]      FIG. 1  is a perspective view of an external appearance of a lens holder driving device according to a first embodiment of the present invention; 
           [0021]      FIG. 2  is an exploded perspective view of the lens holder driving device illustrated in  FIG. 1 ; 
           [0022]      FIG. 3  is a longitudinal sectional view taken along the line of  FIG. 1 ; 
           [0023]      FIG. 4  is a longitudinal sectional view taken along the line IV-IV of  FIG. 1 ; 
           [0024]      FIG. 5  is a plan view illustrating a shape of an upper leaf spring used for the lens holder driving device illustrated in  FIG. 1  as viewed from a base member; 
           [0025]      FIG. 6  is a plan view illustrating a shape of a lower leaf spring used for the lens holder driving device illustrated in  FIG. 1  as viewed from base member; 
           [0026]      FIG. 7  is a plan view illustrating a relationship between the upper leaf spring illustrated in  FIG. 5  and the lower leaf spring illustrated in  FIG. 6 ; 
           [0027]      FIGS. 8A and 8B  are drawings for describing a conductor pattern formed in a flexible printed circuit (FPC) used for the lens holder driving device illustrated in  FIG. 1 ,  FIG. 8A  being a front view of the lens holder driving device;  FIG. 8B  showing a relationship between seven terminals of the conductor pattern of flexible printed circuit (FPC) and terminals connected to the seven terminals; 
           [0028]      FIG. 9  is a plan view illustrating an assembly of the lens holder driving device illustrated in  FIG. 1  as viewed from the base member, and illustrates a state before an elastic adhesive agent is provided (applied) to the lower leaf spring; 
           [0029]      FIG. 10  is a plan view illustrating the assembly of the lens holder driving device illustrated in  FIG. 1  as viewed from the base member, and illustrates a state after the elastic adhesive agent is provided (applied) to the lower leaf spring; 
           [0030]      FIG. 11  is a partially enlarged view illustrating a part of  FIG. 9  in an enlarged manner; 
           [0031]      FIG. 12  is a partially enlarged view illustrating a part of  FIG. 10  in an enlarged manner; 
           [0032]      FIG. 13  is a front view of the lens holder driving device illustrated in  FIG. 1 ; 
           [0033]      FIG. 14  is a back view of the lens holder driving device illustrated in  FIG. 1 ; 
           [0034]      FIG. 15  is a perspective view of a yoke used for the lens holder driving device illustrated in  FIG. 1 ; 
           [0035]      FIG. 16  is a front view of the yoke used for the lens holder driving device illustrated in  FIG. 1 ; 
           [0036]      FIG. 17  is a perspective view illustrating an assembly in which a spacer (inner housing), a driving magnet and an upper leaf spring are installed to the yoke in the lens holder driving device illustrated in  FIG. 1 ; 
           [0037]      FIG. 18  is a perspective view illustrating an assembly in which the upper leaf spring is installed to the spacer (inner housing) in the lens holder driving device illustrated in  FIG. 1 ; 
           [0038]      FIG. 19  is a longitudinal sectional view taken along the line IV-IV of  FIG. 1 ; 
           [0039]      FIG. 20  is a cross-sectional perspective view specifically illustrating a part of (front side) a cross-section of  FIG. 19 ; 
           [0040]      FIG. 21  is a cross-sectional perspective view specifically illustrating a part (rear side) of the cross-section of  FIG. 19 ; 
           [0041]      FIG. 22  is a perspective view of the lens holder driving device illustrated in  FIG. 1  in which a flexible printed circuit (FPC) is omitted; 
           [0042]      FIG. 23A  is a front view illustrating the flexible printed circuit (FPC) used for the lens holder driving device illustrated in  FIG. 1 ; 
           [0043]      FIG. 23B  is a back view illustrating the flexible printed circuit (FPC) used for the lens holder driving device illustrated in  FIG. 1 ; 
           [0044]      FIG. 23C  is a plan view (top view) illustrating the flexible printed circuit (FPC) used for the lens holder driving device illustrated in  FIG. 1 ; 
           [0045]      FIG. 24A  is a front view illustrating a base material of flexible printed circuit (FPC) illustrated in  FIG. 23A ; 
           [0046]      FIG. 24B  is a back view illustrating the base material of the flexible printed circuit (FPC) illustrated in  FIG. 23B ; 
           [0047]      FIG. 25A  is a front view illustrating a state where a hole sensor is installed to the flexible printed circuit (FPC) in the lens holder driving device illustrated in  FIG. 1 ; 
           [0048]      FIG. 25B  is a back view illustrating a state where the hole sensor is installed to the flexible printed circuit (FPC) in the lens holder driving device illustrated in  FIG. 1 ; 
           [0049]      FIG. 25C  is a plan view illustrating (top view) a state where the hole sensor is installed to the flexible printed circuit (FPC) in the lens holder driving device illustrated in  FIG. 1 ; 
           [0050]      FIG. 25D  is a perspective view as viewed from the front surface side illustrating a state where the hole sensor is installed to the flexible printed circuit (FPC); 
           [0051]      FIG. 25E  is a perspective view as viewed from the back side illustrating a state where the hole sensor is installed to the flexible printed circuit (FPC) in the lens holder driving device illustrated in  FIG. 1 ; 
           [0052]      FIG. 26  is a plan view that illustrates the lens holder driving device illustrated in  FIG. 1  and a connection state of the flexible printed circuit (FPC); 
           [0053]      FIG. 27  is a partially enlarged cross-sectional perspective view illustrating a region around cone-shaped depressions of the flexible printed circuit (FPC) of  FIG. 26  in an enlarged manner; 
           [0054]      FIG. 28  is a partially enlarged perspective view illustrating a region around a protrusion part of the yoke of  FIG. 26  in an enlarged manner; 
           [0055]      FIG. 29  is a perspective view of the lens holder driving device illustrated in  FIG. 1 ; 
           [0056]      FIG. 30  is a partially enlarged view illustrating an abutting portion of an upper leaf spring and a ring-shaped upper end part of the yoke of  FIG. 29  in an enlarged manner; 
           [0057]      FIG. 31  is a perspective view of the spacer (inner housing) used for the lens holder driving device illustrated in  FIG. 1 ; 
           [0058]      FIG. 32  is a partially enlarged view illustrating a part of  FIG. 31  in an enlarged manner; 
           [0059]      FIG. 33  is a perspective view illustrating a camera-equipped mobile terminal in which the lens holder driving device illustrated in  FIG. 1  is installed; 
           [0060]      FIG. 34  is a perspective view of a lens holder driving device according to a second embodiment of the present invention in which the yoke, the upper leaf spring, and the spacer (inner housing) are omitted; 
           [0061]      FIG. 35  is a plan view of the lens holder driving device illustrated in  FIG. 34 ; 
           [0062]      FIG. 36  is a perspective view of a lens holder driving device according to a third embodiment of the present invention in which the yoke, the upper leaf spring, and the spacer (inner housing) are omitted; and 
           [0063]      FIG. 37  is a plan view of the lens holder driving device illustrated in  FIG. 36 . 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0064]    In the following, embodiments of the present invention are described with reference to the accompanying drawings. 
       First Embodiment 
       [0065]    With reference to  FIG. 1  to  FIG. 4 , lens holder driving device  10  according to a first embodiment of the present invention is described. 
         [0066]      FIG. 1  is a perspective view illustrating an external appearance of lens holder driving device  10 .  FIG. 2  is an exploded perspective view of lens holder driving device  10 .  FIG. 3  is a longitudinal sectional view taken along the line of  FIG. 1 .  FIG. 4  is a longitudinal sectional view taken along the line IV-IV of  FIG. 1 . 
         [0067]    Here, as illustrated in  FIG. 1  to  FIG. 4 , an orthogonal coordinate system (X, Y, Z) is used. In the orthogonal coordinate system (X, Y, Z) of  FIG. 1  to  FIG. 4 , the X-axis direction is the front-rear direction (depth direction), the Y-axis direction is the horizontal direction (width direction), and the Z-axis direction is the vertical direction (height direction). In addition, in the example illustrated in  FIG. 1  to  FIG. 4 , vertical direction Z is the direction of optical axis O of the lens. It is to be noted that, in the present embodiment, the Y-axis direction (horizontal direction) is also referred to as first direction, and the X-axis direction (front-rear direction) is also referred to as second direction. 
         [0068]    It should be noted that, when actually used, the direction of optical axis O, that is, the Z-axis direction is the front-rear direction. In other words, the upward direction of the Z axis is the forward direction, and the downward direction of the Z axis is the rearward direction. 
         [0069]    Lens holder driving device  10  illustrated in the drawing is a lens holder driving device that employs a voice coil motor (VCM) system using a VCM as the driving mechanism (actuator). The lens holder driving device of the VCM type includes a driving coil, and a magnetic circuit composed of a yoke and a permanent magnet as the driving mechanism (actuator) as described later. Lens holder driving device  10  illustrated in the drawing employs a driving mechanism of “moving coil type” as the driving mechanism of the VCM type. 
         [0070]    Lens holder driving device  10  illustrated in the drawing is used in a mobile terminal capable of performing auto focus (AF) such as a camera-equipped mobile phone, a smartphone described later illustrated in  FIG. 33 , a note-type personal computer, a tablet-type personal computer, a mobile game machine, a Web camera, and an in-vehicle camera. 
         [0071]    Lens holder driving device  10  illustrated in the drawing is intended for moving lens holder  14  (described later) that holds lens barrel  11  in the direction of optical axis O. Accordingly, optical axis O is the driving axis (central axis). Lens holder driving device  10  includes base member (actuator base)  12  disposed on the lower side (rear side) in the Z-axis direction (the direction of optical axis O). 
         [0072]    At a lower portion (rear portion) of base member (actuator base)  12 , a sensor substrate (not illustrated) is disposed. On the sensor substrate, electronic components such as an imaging device and a clock generation source are installed. Lens holder driving device  10  and the sensor substrate are covered with a shield case (not illustrated). The shield case blocks electromagnetic noise generated by the sensor substrate. 
         [0073]    A camera module is composed of a combination of lens holder driving device  10 , the sensor substrate, the imaging device, and the shield case. 
         [0074]    The imaging device captures a subject image imaged by lens barrel  11  and converts the image into an electric signal. The imaging device is composed of, for example, a charge coupled device (CCD) image sensor, a complementary metal oxide semiconductor (CMOS) image sensor or the like. 
         [0075]    Lens holder driving device  10  includes: lens holder  14  including cylindrical part  140  for holding lens barrel  11 ; ring-shaped driving coil  16  fixed to lens holder  14  such that it is located at the outer periphery of cylindrical part  140 ; yoke  20  having a substantially quadrangular cylindrical shape including driving magnet  18  that is opposite to driving coil  16 ; and a pair of leaf springs  22  and  24  provided on both sides of cylindrical part  140  of lens holder  14  in the direction of optical axis O. 
         [0076]    To attach lens barrel  11  to lens holder  14 , lens barrel  11  is housed in lens holder  14 , and lens barrel  11  and lens holder  14  are joined to each other with adhesive agent or the like. 
         [0077]    In addition, the magnetic circuit is composed of a combination of driving magnet  18  and yoke  2 . 
         [0078]    The pair of leaf springs  22  and  24  supports lens holder  14  such that lens holder  14  is displaceable in the direction of optical axis O while setting the position of lens holder  14  in the radial direction. Regarding the pair of leaf springs  22  and  24 , leaf spring  22  is referred to as upper leaf spring, and leaf spring  24  is referred to as lower leaf spring. 
         [0079]    In addition, as described above, when actually used, the upward direction of the Z-axis direction (the direction of optical axis O) is the forward direction, and the downward direction of the Z-axis direction (the direction of optical axis O) is the rearward direction. Accordingly, upper leaf spring  22  is also referred to as front spring, and lower leaf spring  24  is also referred to as rear spring. 
         [0080]    Upper leaf spring (front spring)  22  and lower leaf spring (rear spring)  24  are formed of a metal such as stainless steel, beryllium copper and nickel copper. In addition, upper leaf spring (front spring)  22  and lower leaf spring (rear spring)  24  is manufactured by working such as etching using photolithographic technique and pressing with a predetermined thin plate. Regarding the working, etching is preferable than pressing. 
         [0081]    The reason for this is that no residual stress is left in the leaf spring which has been subjected to etching. 
         [0082]    In addition, preferably, the material of the leaf spring is stainless steel, or in particular, high-hardness stainless steel than beryllium copper. The reason for this is that a compound of beryllium is known to be highly toxic, and it is desirable to use materials other than beryllium copper as the material of the leaf spring (beryllium free) from the standpoint of environmental conservation. It is to be noted that as the high-hardness stainless steel, NTK S-4 or NTK 301 (SUS301) available from Nippon Metal Industry Co., Ltd. may be used. 
         [0083]    As illustrated in  FIG. 1  and  FIG. 2 , yoke  20  has a substantially quadrangular cylindrical shape. That is, yoke  20  includes outer cylinder part  202  having a substantially square cylindrical shape, and upper end portion  204  having a substantially quadrangular ring shape protruding to the inner side of outer cylinder part  202  at the upper end (front end) of outer cylinder part  202 . In addition, at the four corners of the inner side of ring-shaped upper end part  204 , yoke  20  includes four inner vertical extending parts  206  extending perpendicularly downward in a direction parallel to optical axis O. 
         [0084]    Accordingly, driving coil  16  also has a substantially quadrangular cylindrical shape that matches the substantially quadrangular cylindrical shape of yoke  20 . Specifically, driving coil  16  has an octagonal cylindrical shape with four long side parts  162  disposed to be parallel to and opposite to the four sides of yoke  20 , and four short side parts  164  that are opposite to the four corners of yoke  20 . Driving coil  16  is attached to the exterior wall of cylindrical part  140  of lens holder  14  in a region on a side closer to upper leaf spring  22  such that driving coil  16  is housed in a space between outer cylinder part  202  of yoke  20  and four inner vertical extending parts  206 . 
         [0085]    As illustrated in  FIG. 2  and  FIG. 3 , driving magnet  18  illustrated in the drawing is composed of two plate-shaped driving magnet pieces  182  that are disposed at two inner wall surfaces of outer cylinder part  202  of yoke  20  which are opposite to each other in horizontal direction Y such that two plate-shaped driving magnet pieces  182  are opposite to driving coil  16  with a space therebetween. In other words, each plate-shaped driving magnet piece  182  is extended such that the both ends thereof in the horizontal direction are located at a region close to the two sides of yoke  20  opposite to each other in the front-rear direction X. In addition, driving coil  16  is disposed such that it is close to a region around the both ends of each plate-shaped driving magnet piece  182  in the horizontal direction. 
         [0086]    With this structure, reduction in the magnetic efficiency of the magnetic circuit can be suppressed. 
         [0087]    Each plate-shaped driving magnet piece  182  is magnetized in the radial direction, and the inner periphery side and the outer periphery side thereof are magnetized in different polarities. In the example illustrated in the drawing, each plate-shaped driving magnet piece  182  is magnetized such that the inner periphery side is magnetized to N pole, and the outer periphery side is magnetized to S pole as illustrated in  FIG. 3 . 
         [0088]    The driving mechanism of “moving coil type” is composed of the combination of driving coil  16 , two plate-shaped driving magnet pieces  182  and yoke  20 . 
         [0089]    Outer cylinder part  202  of yoke  20  is composed of front plate part  202 F and rear plate part  202 B that are opposite to each other in front-rear direction X, and left plate part  202 L and right plate part  202 R that are opposite to each other in horizontal direction Y. Front plate part  202 F includes front cutout part  202   a  that opens downward, and rear plate part  202 B includes rear cutout part  202   b  that opens downward. Front plate part  202 F includes protrusion part  207  that protrudes downward at front cutout part  202   a . Front plate part  202 F is also referred to as first plate part, and rear plate part  202 B is also referred to as second plate part. In addition, front cutout part  202   a  is also referred to as first cutout part, and rear cutout part  202   b  is also referred to as second cutout part. 
         [0090]    On the other hand, base member (actuator base)  12  includes base part  120  having a rectangular ring-shape, and a pair of protruding parts  122  and  123  that are opposite to each other in front-rear direction X and protrude upward in vertical direction Z from base part  120 . Here, protruding part  122  provided on the front side is referred to as front protruding part, and protruding part  123  provided on the rear side is referred to as rear protruding part. In addition, front protruding part  122  is also referred to as first protruding part, and rear protruding part  123  is also referred to as second protruding part. 
         [0091]    Lens holder driving device  10  illustrated in the drawing further includes spacer  30  provided between base member (actuator base)  12  and yoke  20 . Spacer  30  is also referred to as inner housing. Spacer (inner housing)  30  has a shape which is substantially housed in the inner wall surface of yoke  20 . To be more specific, spacer (inner housing)  30  includes: ring-shaped part  302  having a rectangular external shape provided at the upper portion of the inner wall surface of outer cylinder part  202  of yoke  20 ; four vertical extending parts  304  perpendicularly extending in a downward direction parallel to optical axis O from the four corners of ring-shaped part  302 ; and a pair of U-shaped plate parts  305  and  306  extending in a downward direction parallel to optical axis O from a pair of the sides of ring-shaped part  302  which are opposite to each other in front-rear direction X. 
         [0092]    Here, U-shaped plate part  305  provided on the front side is referred to as front U-shaped plate part, and U-shaped plate part  306  provided on the rear side is referred to as rear U-shaped plate part. In addition, front U-shaped plate part  305  is also referred to as first U-shaped plate part, and rear U-shaped plate part  306  is also referred to as second U-shaped plate part. 
         [0093]    The fixing part ( 12 ,  30 ) is composed of the combination of base member (actuator base)  12  and spacer (inner housing)  30 . 
         [0094]    As illustrated in  FIG. 2  and  FIG. 4 , in a region around front cutout part (first cutout part)  202   a  of yoke  20 , front protruding part (first protruding part)  122  of base member  12  and front U-shaped plate part (first U-shaped plate part)  305  of spacer (inner housing)  30  are engaged with each other (in engagement). In addition, in a region around rear cutout part (second cutout part)  202   b  of yoke  20 , rear protruding part (second protruding part)  123  of base member  12  and rear U-shaped plate part (second cutout part)  306  of spacer (inner housing)  30  are engaged with each other (in engagement). 
         [0095]    It is to be noted that front protruding part (first protruding part)  122  of base member  12  has rectangular hole  122   a  through which hole sensor  344  that is the magnetic detection device described later is inserted. In addition, cylindrical part  140  of lens holder  14  includes a pair of housing parts  140   a  for housing a pair of sensor magnets  342   a  and  342   b  described later at lower portions of the exterior walls opposite to each other in front-rear direction X with the Z axis (optical axis O) as the center. 
         [0096]    Lens holder driving device  10  illustrated in the drawing further includes position detection part  34  that detects the position of lens holder  14  in the direction of optical axis O. 
         [0097]    As illustrated in  FIG. 2  and  FIG. 4 , position detection part  34  is provided in a region on a side closer to lower leaf spring  24 . To be more specific, position detection part  34  includes one of the pair of sensor magnets  342   a  and  342   b  housed in the above-mentioned pair of housing parts  140   a  of cylindrical part  140  of lens holder  14  (in the example illustrated in the drawing, front side sensor magnet  342   a ), and hole sensor  344  that is inserted in rectangular hole  122   a  of base member  12  in such a manner as to be opposite to sensor magnet  342   a.    
         [0098]    Sensor magnets  342   a  and  342   b  are magnetized in the direction of optical axis O, and the top surface side and the bottom surface side thereof are magnetized in different polarities. In the example illustrated in the drawing, each of sensor magnets  342   a  and  342   b  is magnetized such that the top surface side is magnetized to S pole, and the bottom surface side is magnetized to N pole as illustrated in  FIG. 4 . 
         [0099]    In the first embodiment, permanent magnets whose Curie point is 400° C. or above are used as sensor magnets  342   a  and  342   b . Examples of such a permanent magnet include a samarium-cobalt magnet, a ferrite magnet, and an alnico magnet. With this configuration, thermal demagnetization of sensor magnets  342   a  and  342   b  when in use can be suppressed. 
         [0100]    As described, in the first embodiment, driving magnets  18  and the pair of sensor magnets  342   a  and  342   b  of position detection part  30  are separated from each other. Accordingly, position detection part  34  can be prevented from being negatively influenced by the magnetic flux generated at driving magnet  18 . As a result, position detection part  34  can correctly detect the position of lens holder  14  in the direction of optical axis O. 
         [0101]    In addition, in the first embodiment, as illustrated in  FIG. 3  and  FIG. 4 , by optimizing the polarity of two plate-shaped driving magnet pieces  182  and the polarity of the pair of sensor magnets  342   a  and  342   b , the interference therebetween can be effectively used. To be more specific, yoke  20  itself is set to S pole when driving magnet  18  is disposed on the inner wall surface of yoke  20 . When the side (upper side) of sensor magnets  342   a  and  342   b  closer to yoke  20  is set to S pole, the initial position is set by the balance with the spring force of leaf springs  22  and  24  although slight magnetic interference (repulsion direction) exists. Assuming that the upper side of sensor magnets  342   a  and  342   b  is set to N pole, the attraction with yoke  20  is large, and the initial position is unstable. 
         [0102]    It is to be noted that the magnetic interference is small when the magnetic force of sensor magnets  342   a  and  342   b  is set to a small value. With such a configuration, however, the output of hole sensor  344  is also small, and the S/N ratio of the output of hole sensor  344  is deteriorated. Accordingly, it is desirable to dispose sensor magnets  342   a  and  342   b  at positions remote from yoke  20 , and the position of hole sensor  344  is optimally set with the influence of the magnetic interference included. That is, it is desirable to dispose sensor magnets  342   a  and  342   b  at positions which are remote from yoke  20  as much as possible, and are farthest from driving magnet  18 . 
         [0103]    Further, since the pair of sensor magnets  342   a  and  342   b  are disposed at positions which are point symmetrical about optical axis O, the dynamic balance with lens holder driving device  10  can be ensured. As a result, the movable part can be vertically moved in the direction of optical axis O in a stable manner. 
         [0104]    Furthermore, by disposing the pair of sensor magnets  342   a  and  342   b  at positions which are point symmetrical about optical axis O, the effect of the magnetic interference from the pair of sensor magnets  342   a  and  342   b  to the magnetic circuit (driving magnet  18 , yoke  20 ) can be ensured. As a result, it also is possible to reduce the transient response time of the vertical movement of the movable part in the direction of optical axis O. 
         [0105]    It is to be noted that the polarities of two plate-shaped driving magnet pieces  182  and the polarities of the pair of sensor magnets  342   a  and  342   b  are not limited to the polarities illustrated in  FIG. 3  and  FIG. 4 , and may be opposite to each other. That is, plate-shaped driving magnet pieces  182  may be magnetized such that the inner periphery side is magnetized to S pole, and the outer periphery side is magnetized to N pole, and, sensor magnets  342   a  and  342   b  may be magnetized such that the top surface side is magnetized to N pole, and the bottom surface side is magnetized to S pole. 
         [0106]    It is to be noted that, as illustrated in  FIG. 2  and  FIG. 4 , hole sensor  344  is installed on flexible printed circuit (FPC)  40 . As illustrated in  FIG. 1  and  FIG. 4 , at front cutout part  202   a  of yoke  20 , flexible printed circuit (FPC)  40  is attached to the exterior wall of front protruding part  122  of base member  12  in a state where it is inserted in protrusion part  207  of yoke  20 . As illustrated in  FIG. 1 , flexible printed circuit (FPC)  40  is provided with a pair of cone-shaped depressions  401  recessed inward at both end side portions thereof in horizontal direction Y. 
         [0107]    It is to be noted that the pair of sensor magnets  342   a  and  342   b  are respectively housed in the pair of housing parts  140   a  formed at lower portions of the exterior walls opposite to each other in front-rear direction X with the Z axis (optical axis O) as the center in cylindrical part  140  of lens holder  14  for the purpose of maintaining the balance between the moving state and the stopping state of lens holder  14 , achieving uniform weight disposition around the Z axis (optical axis O), and equalizing the magnetic interference force (resilience) with plate-shaped driving magnet piece  182 . Accordingly, assuming that one sensor magnet  342   a  and plate-shaped driving magnet piece  182  are separated from each other by a certain distance and that the magnetic interference has no influence, the other sensor magnet  342   b  that is not opposite to hole sensor  344  can be replaced by a weight having a similar weight which is not magnetized. 
         [0108]    Upper leaf spring (front spring)  22  is disposed on the upper side (front side) of lens holder  14  in the direction of the optical axis O, and lower leaf spring (rear spring)  24  is disposed on the lower side (rear side) of lens holder  14  in the direction of optical axis O. 
         [0109]    With reference to  FIG. 5  to  FIG. 7 , the shapes of upper leaf spring  22  and lower leaf spring  24  and their relationship are described. 
         [0110]      FIG. 5  is a plan view illustrating a shape of upper leaf spring  22  as viewed from base member  12 .  FIG. 6  is a plan view illustrating a shape of lower leaf spring  24  as viewed from base member  12 .  FIG. 7  is a plan view illustrating a relationship between upper leaf spring  22  and lower leaf spring  24 . 
         [0111]    First, with reference to  FIG. 5 , the shape of upper leaf spring  22  is described. 
         [0112]    Upper leaf spring  22  includes upper inner periphery end part  222  that is attached to an upper end portion of lens holder  14 , and upper outer periphery end part  224  that is attached to ring-shaped part  302  of spacer  30 . Four upper arm parts  226  are provided between upper inner periphery end part  222  and upper outer periphery end part  224  along the circumferential direction. Each upper arm part  226  connects upper inner periphery end part  222  and upper outer periphery end part  224 . Each upper arm part  226  has a U-turn-shaped portion  226   a  that is folded-back by 180 degrees. 
         [0113]    Next, with reference to  FIG. 6 , the shape of lower leaf spring  24  is described. 
         [0114]    Lower leaf spring  24  includes lower inner periphery end part  242  that is attached to a lower end portion of lens holder  14 , and lower outer periphery end part  244  that is attached to actuator base (base member)  12 . Four lower arm parts  246  are provided between lower inner periphery end part  242  and lower outer periphery end part  244  along the circumferential direction. Each lower arm part  246  connects lower inner periphery end part  242  and lower outer periphery end part  244 . Each lower arm part  246  has U-turn-shaped portion  246   a  that is folded-back by 180 degrees. 
         [0115]    Next, with reference to  FIG. 7 , the relationship between upper leaf spring  22  and lower leaf spring  24  is described. 
         [0116]    As illustrated in  FIG. 7 , four upper arm parts  226  of upper leaf spring  22  and four lower arm parts  246  of lower leaf spring  24  have substantially the same shape in plan view. 
         [0117]    Next, the way for feeding power to driving coil  16  is described. 
         [0118]    As illustrated in  FIG. 6 , for the purpose of achieving power feeding to driving coil  16  through lower leaf spring  24 , lower leaf spring  24  is composed of first and second spring pieces  24 - 1  and  24 - 2  that are electrically isolated from each other. The shapes of first leaf spring piece  24 - 1  and second leaf spring piece  24 - 2  are substantially rotationally symmetrical about optical axis O of the lens. 
         [0119]    First leaf spring piece  24 - 1  has first external connection terminal  244 - 1  protruding forward from lower outer periphery end part  244 . Second leaf spring piece  24 - 2  has second external connection terminal  244 - 2  protruding forward from lower outer periphery end part  244 . 
         [0120]    On the other hand, first leaf spring piece  24 - 1  has first terminal part  242 - 1  protruding rearward from lower inner periphery end part  242 . Second leaf spring piece  24 - 2  has second terminal part  242 - 2  protruding forward from lower inner periphery end part  242 . First terminal part  242 - 1  is electrically connected to a first terminal end part (not illustrated) of driving coil  16  by soldering. Second terminal part  242 - 2  is electrically connected to a second terminal end part (not illustrated) of driving coil  16  by soldering. 
         [0121]    As illustrated in  FIG. 1 , first and second external connection terminals  244 - 1  and  244 - 2  of lower leaf spring  24  are provided to protrude outward from the pair of cone-shaped depressions  401  of flexible printed circuit (FPC)  40 . 
         [0122]    Accordingly, flexible printed circuit (FPC)  40  is electrically connected with the first terminal end part of driving coil  16  through first external connection terminal  244 - 1  of lower leaf spring  24 , and first leaf spring piece  24 - 1  and first terminal part  242 - 1  of lower leaf spring  24 . Likewise, flexible printed circuit (FPC)  40  is electrically connected with the second terminal end part of driving coil  16  through second external connection terminal  244 - 2  of lower leaf spring  24 , and second leaf spring piece  24 - 2  and second terminal part  242 - 2  of lower leaf spring  24 . 
         [0123]    In this manner, power is fed from flexible printed circuit (FPC)  40  to driving coil  16  through lower leaf spring  24 . 
         [0124]    When coil  16  is energized, a driving force in the direction of optical axis O is generated in lens holder  14  (lens barrel  11 ) with the interaction between the magnetic field of driving magnet  18  and the magnetic field of the current flowing through driving coil  16 , and the driving force and the restoration force (biasing force) of the pair of leaf springs  22  and  24  are balanced, whereby the position of lens holder  14  (lens barrel  11 ) in the direction of optical axis O can be adjusted. 
         [0125]    With reference to  FIGS. 8A and 8B , the conductor pattern of the terminal part formed in flexible printed circuit (FPC)  40  is described.  FIG. 8A  is a front view of lens holder driving device  10 , and  FIG. 8B  illustrates a relationship between seven terminals of the conductor pattern of flexible printed circuit (FPC)  40  and terminals which are connected to the seven terminals. 
         [0126]    As illustrated in  FIG. 8A , flexible printed circuit (FPC)  40  includes, as the conductor pattern, first to seventh terminals Pin 1  to Pin 7  which are disposed from the right side to the left side. 
         [0127]    As illustrated in  FIG. 8B , first terminal Pin 1  is connected with ACT Terminal (+) that is first external connection terminal  244 - 1  of lower leaf spring  24 , second terminal Pin 2  is connected with first output terminal Hall output (?) of hole sensor  344 , and third terminal Pin 3  is connected with first input terminal Hall input (+) of hole sensor  344 . Fourth terminal Pin 4  is connected with ground terminal GND. Fifth terminal Pin 5  is connected with second output terminal Hall output (+) of hole sensor  344 , sixth terminal Pin 6  is connected with first input terminal Hall input (?) of Hall device  344 , and seventh terminal Pin 7  is connected with ACT Terminal (?) that is second external connection terminal  244 - 2  of lower leaf spring  24 . 
         [0128]    Next, with reference to  FIG. 9  to  FIG. 12 , details of the configuration of lower leaf spring  24  are described. 
         [0129]      FIG. 9  and  FIG. 10  are plan views of the assembly of lens holder driving device  10  as viewed from base member  12 .  FIG. 9  illustrates a state before elastic adhesive agent  45  described later is provided (applied) to lower leaf spring  24 , and  FIG. 10  illustrates a state after elastic adhesive agents  45  is provided (applied) to lower leaf spring  24 .  FIG. 11  is a partially enlarged view illustrating a part of  FIG. 9  in an enlarged manner, and  FIG. 12  is a partially enlarged view illustrating a part of  FIG. 10  in an enlarged manner. 
         [0130]    As illustrated in  FIG. 10  and  FIG. 12 , lower leaf spring  24  is provided with elastic adhesive agents  45  at U-turn-shaped portions  246   a  of four lower arm parts  246 . Each elastic adhesive agent  45  is provided as a bridge between opposite portions of U-turn-shaped portion  246   a . Four elastic adhesive agents  45  are provided at equal angular intervals in the circumferential direction around optical axis O. 
         [0131]    It is to be noted that elastic adhesive agent  45  is composed of a stretchable and flexible resin. In this example, as elastic adhesive agent  45 , a moisture-curable adhesive agent selected from among silicone-based adhesive agent and silyl group terminated polymer-based adhesive agent is used. 
         [0132]    As illustrated in  FIG. 9  and  FIG. 11 , U-turn-shaped portions  246   a  of four lower arm parts  246  have positioning protrusions  247  for facilitating the bridging of elastic adhesive agent  45  with its surface tension at the above-mentioned opposite portions (that is, the portions where elastic adhesive agent  45  is applied). 
         [0133]    By applying elastic adhesive agent  45  at U-turn-shaped portions  246   a  of four lower arm parts  246  in the above-mentioned manner, lens holder driving device  10  according to the present embodiment suppresses the secondary resonance (sub resonance) which is sway in the arrow direction of  FIG. 12 . In addition, elastic adhesive agent  45  is provided at U-turn-shaped portions  246   a  of four lower arm parts  246 , and therefore does not limit the original stroke of lens holder  14 . 
         [0134]    It is to be noted that elastic adhesive agent  45  can provide its function with no problem even when washing solution is present. Accordingly, as usual, lens holder driving device  10  can be washed after lens holder driving device  10  is assembled and the quality can be maintained. 
         [0135]    In addition, while stretchable and flexible resin is provided to lower leaf spring  24  by applying elastic adhesive agent  45  in this example, the present invention is not limited to this. For example, the stretchable and flexible resin may be provided to lower leaf spring  24  by bonding an elasticity sheet of such a stretchable and flexible resin to lower leaf spring  24  with a double-sided tape. Alternatively, the stretchable and flexible resin may be provided to lower leaf spring  24  by molding lower leaf spring  24  and stretchable and flexible resin in two colors by outsert molding. Further, stretchable and flexible resin may also be provided to lower leaf spring  24  by UV curing a photoresist. In addition, the place where the stretchable and flexible resin is provided is not limited to lower leaf spring  24 , and it is also effective to provide the stretchable and flexible resin at upper leaf spring  22  or both of leaf springs  22  and  24 . 
         [0136]    Next, with reference to  FIG. 13  to  FIG. 16 , front cutout part (first cutout part)  202   a  and rear cutout part (second cutout part)  202   b  formed in yoke  20  are described. 
         [0137]      FIG. 13  is a front view of lens holder driving device  10 , and  FIG. 14  is a back view of lens holder driving device  10 .  FIG. 15  is a perspective view of yoke  20 , and  FIG. 16  is a front view of yoke  20 . 
         [0138]    Front plate part (first plate part)  202 F of yoke  20  has front cutout part (first cutout part)  202   a  having a trapezoidal shape, and likewise, rear plate part (second plate part)  202 B has rear cutout part (second cutout part)  202   b  having a trapezoidal shape. 
         [0139]    By employing yoke  20  of the above-mentioned structure, the pair of sensor magnets  342   a  and  342   b  (see  FIG. 2 ) is prevented from being negatively influenced by the magnetic field generated by a magnetic circuit composed of yoke  20  and driving magnet  18 . In other words, the influence of magnetic field of the above-mentioned magnetic circuit on the pair of sensor magnets  342   a  and  342   b  can be equalized, and, reduced as much as possible. As a result, it is possible to suppress the non-uniformity of the thrust by the stroke amount of the movable part (lens barrel  11  and lens holder  14 ). 
         [0140]    Next, with reference to  FIG. 17  to  FIG. 21 , a structure in which base member  12  and yoke  20  are fitted together through spacer (inner housing)  30  is described. 
         [0141]      FIG. 17  is a perspective view illustrating an assembly in which spacer (inner housing)  30 , driving magnet  18  and upper leaf spring  22  are installed in yoke  20 .  FIG. 18  is a perspective view illustrating an assembly in which upper leaf spring  22  is installed to spacer (inner housing)  30 .  FIG. 19  is a longitudinal sectional view taken along the line IV-IV of  FIG. 1 .  FIG. 20  is a cross-sectional perspective view specifically illustrating a part (front side) of the cross-section of  FIG. 19 , and  FIG. 21  is a cross-sectional perspective view specifically illustrating a part (rear side) of the cross-section of  FIG. 19 . 
         [0142]    After upper leaf spring  22  is mounted on spacer (inner housing)  30  as illustrated in  FIG. 18 , spacer (inner housing)  30  is installed along the inner wall of yoke  20  as illustrated in  FIG. 17 . 
         [0143]    In addition, as illustrated in  FIG. 19 , spacer (inner housing)  30  is fitted with base member  12 . At this time, as illustrated in  FIG. 20 , in a region around front cutout part (first cutout part)  202   a  of yoke  20 , front protruding part (first protruding part)  122  of base member  12  and front U-shaped plate part (first U-shaped plate part)  305  of spacer (inner housing)  30  are engaged with each other (in engagement). In addition, as illustrated in  FIG. 21 , in a region around rear cutout part (second cutout part)  202   b  of yoke  20 , rear protruding part (second protruding part)  123  of base member  12  and rear U-shaped plate part (second U-shaped plate part)  306  of spacer (inner housing)  30  are engaged with each other (in engagement). 
         [0144]    In addition, by supplying adhesive resin (adhesive agent) by utilizing capillarity to the above-mentioned engaging portion (engagement portion), the gap of the above-mentioned engaging portion (engagement portion) is closed. In this manner, it is possible to prevent dusts and foreign matters from intruding into lens holder driving device  10  from the outside through the gap. 
         [0145]    Thus, the combination of first protruding part  122 , second protruding part  123 , and inner housing  30  serves as a foreign matter intrusion prevention member that prevents foreign matters from intruding into the inside from first and second cutout parts  202   a  and  202   b  of first and second plate parts  202 F and  202 B. 
         [0146]    Next, with reference to  FIG. 22 , a state where hole sensor (magnetic detection device)  344  is attached on base member  12  is described. 
         [0147]      FIG. 22  is a perspective view illustrating lens holder driving device  10  illustrated in  FIG. 1  in which flexible printed circuit (FPC)  40  is omitted. 
         [0148]    As illustrated in  FIG. 2  and  FIG. 22 , hole sensor  344  is inserted to rectangular hole  122   a  formed in front protruding part (first protruding part)  122  of base member  12 . In this manner, the position of hole sensor  344  is set. In addition, in front protruding part  122  of base member  12 , C plane  122   b  is provided around rectangular hole  122   a . Resin such as epoxy resin (adhesive agent) is applied to C plane  122   b  to close the gap between hole sensor  344  and rectangular hole  122   a , and thus lens holder driving device  10  has an enclosed structure. 
         [0149]    With this structure, the position of hole sensor  344  is stabilized at a position, and non-uniformity of the output of hole sensor  344  can be suppressed. In addition, since resin (adhesive agent) is supplied into the gap between hole sensor  344  and base member  12 , rectangular hole  122   a  is closed. As a result, it is possible to prevent intrusion of foreign matters and the like through rectangular hole  122   a.    
         [0150]    With reference to  FIG. 23A  to  FIG. 24B , a configuration of flexible printed circuit (FPC)  40  is described. 
         [0151]      FIG. 23A  to  FIG. 23C  are a front view, a rear view, and a plan view (top view) of flexible printed circuit (FPC)  40 , respectively.  FIG. 24A  and  FIG. 24B  are a front view and a rear view of base material  402  of flexible printed circuit (FPC)  40 , respectively. 
         [0152]    Flexible printed circuit (FPC)  40  is composed of base material  402 , first cover film  404 , and second cover film  406 . 
         [0153]    As illustrated in  FIG. 24A , first conductor pattern  402   a  is formed on the main surface of base material  402 . First conductor pattern  402   a  includes grounding pattern  402   ag  at a center portion thereof. As illustrated in  FIG. 24B , second conductor pattern  402   b  is formed on the rear surface of base material  402 . Second conductor pattern  402   b  is intended for connection of the four terminals of hole sensor  344 . In the example illustrated in the drawing, first and second conductor patterns  402   a  and  402   b  are composed of a Cu pattern. 
         [0154]    As illustrated in  FIG. 23A , first cover film  404  is bonded on the main surface of base material  402  so as to cover a part of first conductor pattern  402   a . First cover film  404  is composed of a black cover film (light shielding film) that blocks light. 
         [0155]    As illustrated in  FIG. 23B , second cover film  406  is bonded on the rear surface of base material  402  so as to cover a part of second conductor pattern  402   b.    
         [0156]    With reference  FIG. 25A  to  FIG. 25E , a state where hole sensor  344  is installed on flexible printed circuit (FPC)  40  is described.  FIG. 25A  to  FIG. 25E  are a front view of, a rear view, a plan view (top view), a perspective view as viewed from the front surface side, and a perspective view as viewed from the back side of the state where hole sensor  344  is installed on flexible printed circuit (FPC)  40 , respectively. 
         [0157]    As illustrated in  FIG. 25B  and  FIG. 25E , hole sensor  344  is joined to second conductor pattern  402   b  by soldering on the rear surface (back surface) side of flexible printed circuit (FPC)  40 . 
         [0158]    Accordingly, as illustrated in  FIG. 25A  and  FIG. 25D , black cover film (light shielding film)  404  is bonded on the main surface of flexible printed circuit (FPC)  40  which is opposite to the rear surface on which hole sensor  344  is attached. In this manner, it is possible to prevent intrusion of light (stray light) into lens holder driving device  10  through the gap between hole sensor  344  and rectangular hole  122   a  (see  FIG. 2 ) of base member  12 . 
         [0159]    Next, with reference to  FIG. 26  to  FIG. 28 , electric connection of flexible printed circuit (FPC)  40 , yoke  20 , and first and second external connection terminals  244 - 1  and  244 - 2  of lower leaf spring  24  is described. 
         [0160]      FIG. 26  is a plan view of lens holder driving device  10  illustrating a connection state of flexible printed circuit (FPC)  40 .  FIG. 27  is a partially enlarged perspective cross-sectional view illustrating a region around cone-shaped depression  401  of flexible printed circuit (FPC)  40  of  FIG. 26  in an enlarged manner.  FIG. 28  is a partially enlarged perspective view illustrating a region around protrusion part  207  of yoke  20  of  FIG. 26  in an enlarged manner. 
         [0161]    As described above, flexible printed circuit (FPC)  40  is provided with a pair of cone-shaped depressions  401  at both end portions in horizontal direction (first direction) Y. In addition, first and second external connection terminals  244 - 1  and  244 - 2  of lower leaf spring  24  are provided to protrude outward from the pair of cone-shaped depressions  401  of flexible printed board (FPC)  40 . Here, first and second external connection terminals  244 - 1  and  244 - 2  of lower leaf spring  24  (see  FIG. 6 ) protrude in the pair of cone-shaped depressions  401  without protruding over the main surface of flexible printed circuit (FPC)  40 . 
         [0162]    As illustrated in  FIG. 26  and  FIG. 27 , first and second external connection terminals  244 - 1  and  244 - 2  (see  FIG. 6 ) of lower leaf spring  24  are joined to the pair of cone-shaped depressions  401  of flexible printed circuit (FPC)  40  with solder  52 . Thus, a large joint area can be achieved. 
         [0163]    In addition, as described above, flexible printed circuit (FPC)  40  is attached on the exterior wall of front protruding part (first protruding part)  122  of base member  12  at front cutout part (first cutout part)  202   a  of yoke  20  in a state where it is inserted to protrusion part  207  of yoke  20 . Protrusion part  207  is Sn-plated. 
         [0164]    As illustrated in  FIG. 26  and  FIG. 28 , at protrusion part  207 , yoke  20  and grounding pattern  402   ag  of flexible printed circuit (FPC)  40  are joined together with solder  54  so as to be conductive. 
         [0165]    With this structure, the resistance value of grounding pattern  402   ag  can be suppressed to a minimum value, and peel-off of flexible printed circuit (FPC)  40  can be prevented. 
         [0166]    In addition, as illustrated in  FIG. 28 , a part of protrusion part  207  of yoke  20  is half-punched. 
         [0167]    Accordingly, flexible printed circuit (FPC)  40  is coupled with base member  12  and spacer (inner housing)  30  with solders  52  and  54  at three positions. As a result, the strength of flexible printed circuit (FPC)  40  can be reinforced. In this manner, peel-off of flexible printed circuit (FPC)  40  can be prevented. In addition, since protrusion part  207  of yoke  20  is half-punched, projecting of solder  54  can be suppressed. 
         [0168]    Next, with reference to  FIG. 29  and  FIG. 30 , an abutting structure between upper leaf spring  22  and ring-shaped upper end part  204  of yoke  20  is described. 
         [0169]      FIG. 29  is a perspective view of lens holder driving device  10 .  FIG. 30  is a partially enlarged view illustrating an abutting portion between upper leaf spring  22  and ring-shaped upper end part  204  of yoke  20  of  FIG. 29  in an enlarged manner. 
         [0170]    As illustrated in  FIG. 29 , ring-shaped upper end part  204  of yoke  20  of  FIG. 29  includes semi-punched portions  204   a  that are semi-punched at eight portions on the inner periphery side. 
         [0171]    When lens holder  14  is moved (driven) upward, upper leaf spring  22  is locked by eight semi-punched portions  204   a  (brought into contact with semi-punched portions  204   a ). That is, eight semi-punched portions  204   a  of yoke  20  act as an upper side stopper (lock member) that limits the upward movement of lens holder  14 . 
         [0172]    Since a plurality of semi-punched portions  204   a  are formed at ring-shaped upper end part  204  of yoke  20 , the strength of yoke  20  can be increased. As a result, even when a camera-equipped mobile terminal having lens holder driving device  10  is mistakenly dropped and the movable part (lens barrel  11  and lens holder  14 ) is brought into contact with yoke  20 , it is possible to suppress deformation of yoke  20 . At the time of the contact, upper leaf spring  22  makes contact with the bottom surfaces of semi-punched portions  204   a  of yoke  20 . That is, the contact is made between metals, and therefore it is possible to suppress deformation of lens holder  14  as a molded article. 
         [0173]    With reference to  FIG. 31  and  FIG. 32 , a configuration of spacer (inner housing)  30  is described in more detail. 
         [0174]      FIG. 31  is a perspective view of spacer (inner housing)  30 .  FIG. 32  is a partially enlarged view illustrating a part of  FIG. 31  in an enlarged manner. 
         [0175]    As illustrated in  FIG. 31 , each of four vertical extending parts  304  provided at four corners of spacer (inner housing)  30  has two protrusions  3042  that protrude outward in the radial direction (in  FIG. 31 , only four protrusions  3042  are illustrated). That is, spacer (inner housing)  30  has eight protrusions  3042  in total. 
         [0176]    As illustrated in  FIG. 32 , each protrusion  3042  has a substantially half columnar shape extending in vertical direction Z (extending in a direction parallel to the direction of optical axis O). Each protrusion  3042  has top end portion  3042   a  having a substantially half cone shape at an upper part thereof. 
         [0177]    Since eight protrusions  3042  are provided at four corners of spacer (inner housing)  30  in the above-mentioned manner, the position of yoke  20  can be accurately set. To be more specific, when yoke  20  is disposed to cover spacer (inner housing)  30 , the inner wall of outer cylinder part  202  of yoke  20  is guided by end portions  3042   a  having a substantially half cone shape, and pushes down eight protrusions  3042  of spacer (inner housing)  30 , and consequently, yoke  20  and spacer (inner housing)  30  are fitted to each other in a lightly pressed state. As a result, rattle of yoke  20  can be prevented. 
         [0178]    With this configuration, shift of the central axis of yoke  20  with respect to optical axis O of the lens can be adjusted. As a result, it is possible to equalize the influence of the interference of the magnetism generated from the magnetic circuit composed of driving magnet  18  and yoke  20  on the pair of sensor magnets  342 . This also makes it possible to limit the level of the sub resonance of lens holder driving device  10  to a small level. 
         [0179]    Lens holder driving device  10  according to the first embodiment controls the position of lens holder  14  in the direction of optical axis O by feedback control as described next. 
         [0180]    First, a driving current is supplied to driving coil  16  to move lens holder  14  in the direction of optical axis O, and the position of lens holder  14  in the direction of optical axis O (detection position) and the detection value detected at hole sensor  344  of position detection part  34  are measured. In this manner, the relationship of the driving current, the detection position, and the detection value is determined. The driving current and the detection position correspond to each other in one-to-one relationship. Accordingly, when moving lens holder  14  to a desired target position (a position in the direction of optical axis O), it suffices to supply driving coil  16  with a driving current corresponding to the target position. 
         [0181]    To achieve conversion of a detection value into a detection position, the relationship between the detection value and the detection position (one-to-one relationship) is stored in a ROM (read-only memory). Accordingly, the ROM serves as a conversion part that converts a detection value into a detection position. 
         [0182]    A control part (not illustrated) for achieving feedback control determines a driving current required for moving lens holder  14  to a target position on the basis of an image signal of the imaging device and a detection value detected by hole sensor  344 , and supplies the determined driving current to driving coil  16 . 
         [0183]    The control part includes the above-mentioned conversion part (ROM), a target position calculation part, a comparison part, and an operation part. The target position calculation part calculates a target position (focusing position) of lens holder  14  based on an image signal of the imaging device. Here, the focusing position is a position of lens holder  14  where the contrast value of a captured image obtained by processing of an image signal is optimized. The comparison part compares the target position and the detection position, and outputs a control deviation. The operation part supplies an operation amount at which the control deviation is zero as a driving current to driving coil  16 . 
         [0184]    By performing feedback control in the above-mentioned manner, lens holder  14  can be stopped at a target position (focusing position) in the direction of optical axis O in a short time of 10 milliseconds to 20 milliseconds, for example. 
         [0185]      FIG. 33  is a perspective view illustrating camera-equipped mobile terminal  80  in which lens holder driving device  10  is installed. Camera-equipped mobile terminal  80  illustrated in the drawing is composed of a smartphone. Lens holder driving device  10  is attached at a predetermined position of camera-equipped mobile terminal  80 . With this structure, the user can capture an image by using camera-equipped mobile terminal  80 . 
         [0186]    While camera-equipped mobile terminal  80  is composed of a smartphone in this example, the camera-equipped mobile terminal may be a camera-equipped mobile phone, a note-type personal computer, a tablet-type personal computer, a mobile game machine, a Web camera, or an in-vehicle camera. 
       Second Embodiment 
       [0187]    With reference to  FIGS. 34 and 35 , lens holder driving device  10 A according to a second embodiment of the present invention is described. 
         [0188]      FIG. 34  is a perspective view of lens holder driving device  10 A in which yoke  20 , upper leaf spring  22 , and spacer (inner housing)  30  are omitted.  FIG. 35  is a plan view of lens holder driving device  10 A illustrated in  FIG. 34 . 
         [0189]    Here, as illustrated in  FIG. 34  and  FIG. 35 , an orthogonal coordinate system (X, Y, Z) is used. In the orthogonal coordinate system (X, Y, Z) of  FIG. 34  and  FIG. 35 , the X-axis direction is the front-rear direction (depth direction), the Y-axis direction is the horizontal direction (width direction), and the Z-axis direction is the vertical direction (height direction). In addition, in the example illustrated in  FIG. 34  and  FIG. 35 , vertical direction Z is the direction of optical axis O of the lens. It is to be noted that, in the present embodiment, the Y-axis direction (horizontal direction) is also referred to as first direction, and the X-axis direction (front-rear direction) is also referred to as second direction. 
         [0190]    It should be noted that, when actually used, the direction of optical axis O, that is, the Z-axis direction is the front-rear direction. In other words, the upward direction of the 
         [0191]    Z axis is the forward direction, and the downward direction of the Z axis is the rearward direction. 
         [0192]    Lens holder driving device  10 A illustrated in the drawing is used in a mobile terminal capable of performing auto focus (AF) such as a camera-equipped mobile phone, a smartphone illustrated in  FIG. 33 , a note-type personal computer, a tablet-type personal computer, a mobile game machine, a Web camera, and an in-vehicle camera. 
         [0193]    Except for the following difference of the driving magnet, lens holder driving device  10 A illustrated in the drawing has a configuration identical to that of lens holder driving device  10  illustrated in  FIG. 1  to  FIG. 4 , and operates similarly to lens holder driving device  10  illustrated in  FIG. 1  to  FIG. 4 . Accordingly, the driving magnet is denoted with reference numeral  18 A. Components having functions similar to those of the components of lens holder driving device  10  illustrated in  FIG. 1  to  FIG. 4  are denoted with the same reference numerals, and the description thereof will be omitted for simplification. 
         [0194]    As with driving magnet  18  according to the first embodiment, driving magnet  18 A is composed of two plate-shaped driving magnet pieces  182 A; however, the shape of driving magnet  18 A is different from that of plate-shaped driving magnet piece  182  of driving magnet  18 . 
         [0195]    Specifically, each of two plate-shaped driving magnet pieces  182 A has, at both end portions thereof, protrusion part  182 Aa having a substantially triangular prism shape that are disposed to be opposite to four short side parts  164  of driving coil  16  at four corners of yoke  20  (see  FIG. 2 ). The inner periphery side of each protrusion part  182 Aa has a planar shape. Accordingly, plate-shaped driving magnet piece  182 A can be readily manufactured. 
         [0196]    Lens holder driving device  10 A according to the second embodiment can achieve an effect similar to that of lens holder driving device  10  according to the first embodiment, and in addition, can achieve an effect described next. 
         [0197]    Specifically, since each of two plate-shaped driving magnet pieces  182 A has protrusion part  182 Aa having a substantially triangular prism shape at both end portions thereof, the thrust of the driving mechanism according to the second embodiment can be advantageously increased in comparison with the driving mechanism according to the first embodiment. 
       Third Embodiment 
       [0198]    With reference to  FIG. 36  and  FIG. 37 , lens holder driving device  10 B according to a third embodiment of the present invention is described. 
         [0199]      FIG. 36  is a perspective view of lens holder driving device  10 B in which yoke  20 , upper leaf spring  22 , and spacer (inner housing)  30  are omitted.  FIG. 37  is a plan view of lens holder driving device  10 B illustrated in  FIG. 36 . 
         [0200]    Here, as illustrated in  FIG. 36  and  FIG. 37 , an orthogonal coordinate system (X, Y, Z) is used. In the orthogonal coordinate system (X, Y, Z) of  FIG. 36  and  FIG. 37 , the X-axis direction is the front-rear direction (depth direction), the Y-axis direction is the horizontal direction (width direction), and the Z-axis direction is the vertical direction (height direction). In addition, in the example illustrated in  FIG. 36  and  FIG. 37 , vertical direction Z is the direction of optical axis O of the lens. It is to be noted that, in the present embodiment, the Y-axis direction (horizontal direction) is also referred to as first direction, and the X-axis direction (front-rear direction) is also referred to as second direction. 
         [0201]    It should be noted that, when actually used, the direction of optical axis O, that is, the Z-axis direction is the front-rear direction. In other words, the upward direction of the Z axis is the forward direction, and the downward direction of the Z axis is the rearward direction. 
         [0202]    Lens holder driving device  10 B illustrated in the drawing is used in a mobile terminal capable of performing auto focus (AF) such as a camera-equipped mobile phone, a smartphone illustrated in  FIG. 33 , a note-type personal computer, a tablet-type personal computer, a mobile game machine, a Web camera, and an in-vehicle camera. 
         [0203]    Except for the following difference of the driving magnet described later, lens holder driving device  10 B illustrated in the drawing has a configuration identical to that of lens holder driving device  10  illustrated in  FIG. 1  to  FIG. 4 , and operates similarly to lens holder driving device  10  illustrated in  FIG. 1  to  FIG. 4 . Components having functions similar to those of the components of lens holder driving device  10  illustrated in  FIG. 1  to  FIG. 4  are denoted with the same reference numerals, and the description thereof will be omitted for simplification. 
         [0204]    Driving magnet  18 B further includes four driving magnet pieces  184  having a substantially triangular prism shape which are respectively opposite to four short side parts  164  of driving coil  16  at four corners of the yoke in addition to two plate-shaped driving magnet pieces  182 . The inner periphery side of each driving magnet piece  184  has a planar shape. Accordingly, driving magnet piece  184  can be readily manufactured. 
         [0205]    Lens holder driving device  10 B according to the third embodiment can achieve an effect similar to that of lens holder driving device  10  according to the first embodiment, and in addition, can achieve an effect described next. 
         [0206]    That is, since driving magnet  18  includes not only two plate-shaped driving magnet pieces  182 , but also four driving magnet pieces  184  having a substantially triangular prism shape, the thrust of the driving mechanism according to the third embodiment can be advantageously increased in comparison with the driving mechanism according to the first embodiment. 
         [0207]    An exemplary mode of the present invention is described below. 
         [0208]    In the exemplary mode of the present invention, a lens holder driving device ( 10 ;  10 A;  10 B) includes: a lens holder ( 14 ) to which a lens barrel ( 11 ) is attachable; a fixing part ( 12 ,  30 ) disposed at an outer periphery of the lens holder ( 14 ); a driving mechanism ( 16 ,  18 ;  18 A;  18 B,  20 ) for driving the lens holder ( 14 ) in a direction of an optical axis (O) of a lens; and a position detection part ( 34 ) configured to detect a position of the lens holder ( 14 ) in the direction of the optical axis (O). The fixing part includes a base member ( 12 ) disposed on a lower side of the lens holder ( 14 ). The driving mechanism includes a yoke ( 20 ) uprightly provided on the base member ( 12 ). The position detection part includes a sensor magnet ( 342   a ) attached on a corresponding outer peripheral surface of the lens holder ( 14 ) in a direction (X) orthogonal to the optical axis (O), and a magnetic detection device ( 344 ) provided to the fixing part such that the magnetic detection device ( 344 ) is opposite to the sensor magnet ( 342   a ). The yoke ( 20 ) includes an outer cylinder part ( 202 ) having a cylindrical shape, and the outer cylinder part ( 202 ) includes a plurality of plate parts ( 202 F,  202 B) which are opposite to each other in the direction (X) orthogonal to the optical axis (O), the plate parts ( 202 F,  292 B) having cutout parts ( 202   a ,  202   b ) at positions opposite to the sensor magnet ( 342   a ). The lens holder driving device ( 10 ;  10 A;  10 B) includes a foreign matter intrusion prevention member ( 122 ,  123 ,  30 ) configured to prevent intrusion of foreign matters from the cutout part ( 202   a ,  202   b ) of the plate part ( 202 F,  202 B). 
         [0209]    In the lens holder driving device ( 10 ;  10 A;  10 B), the lens holder driving device ( 10 ;  10 A;  10 B) may further include an upper leaf spring ( 22 ) configured to couple the lens holder ( 14 ) and the fixing part ( 12 ,  30 ) at an upper part thereof, and a lower leaf spring ( 24 ) configured to couple the lens holder ( 14 ) and the fixing part ( 12 ,  30 ) at a lower part thereof. 
         [0210]    The position detection part ( 34 ) may be provided in a region around the lower leaf spring ( 24 ). The yoke ( 20 ) may have a substantially quadrangular cylindrical shape. Preferably, the driving mechanism may further include a driving coil ( 16 ) fixed at a periphery of the lens holder ( 14 ) in a region on a side closer to the upper leaf spring ( 22 ), and a driving magnet ( 18 ;  18 A;  18 B) including plate-shaped driving magnet pieces ( 182 ;  182 A) which are disposed at a pair of inner wall surfaces of the yoke ( 20 ) opposite to each other in a first direction (Y) orthogonal to the direction of the optical axis (O), the plate-shaped driving magnet pieces ( 182 ;  182 A) being respectively disposed to be opposite to the driving coil ( 16 ). The base member ( 12 ) may include a ring-shaped base part ( 120 ), and first and second protruding parts ( 122 ,  123 ) which are opposite to each other in a second direction 
         [0211]    (X) orthogonal to the direction of the optical axis (O) and the first direction (Y) and protrude upward from the base part ( 120 ), the first protruding part ( 122 ) having a rectangular hole ( 122   a ). The position detection part may include a sensor magnet ( 342   b ) as one of a pair of sensor magnets ( 342   a ,  342   b ) attached on corresponding outer peripheral surfaces of the lens holder ( 14 ) in the second direction (X), and the magnetic detection device ( 344 ) that is inserted to the rectangular hole ( 122   a ) of the first protruding part ( 122 ) of the base member ( 12 ), and firmly fixed with resin, the magnetic detection device ( 344 ) being opposite to the sensor magnet ( 342   a ). The outer periphery part ( 202 ) of the yoke ( 20 ) has a substantially square cylindrical shape. The yoke ( 20 ) may further include a ring-shaped upper end part ( 204 ) having a substantially quadrangular shape protruding inward at an upper end of the outer cylinder part ( 202 ), and an inner vertical extending part ( 206 ) extending perpendicularly downward in a direction parallel to the optical axis (O) at four corners of an inside of the ring-shaped upper end part. The outer cylinder part ( 202 ) may include first and second plate parts ( 202 F,  202 B) that are opposite to each other in the second direction (X) as the plurality of plate parts, the first and second plate parts ( 202 F,  202 B) respectively having first and second cutout parts ( 202   a ,  202   b ) that open downward at positions opposite to the pair of sensor magnets ( 342   a ,  342   b ) as the cutout part. The fixing part may further include an inner housing ( 30 ) provided such that the inner housing ( 30 ) is sandwiched between the base member ( 12 ) and the yoke ( 20 ) and housed in an inner wall surface of the yoke ( 20 ). In this case, a combination of the first protruding part ( 122 ), the second protruding part ( 123 ), and the inner housing ( 30 ) functions as the foreign matter intrusion prevention member. 
         [0212]    Desirably, the inner housing ( 30 ) includes a ring-shaped part ( 302 ) provided at an upper part of an inner wall surface of the outer cylinder part ( 202 ) of the yoke ( 20 ), a vertical extending part ( 304 ) perpendicularly extending downward from four corners of the ring-shaped part ( 302 ) in a direction parallel to the optical axis (O), and first and second 
         [0213]    U-shaped plate parts ( 305 ,  306 ) extending downward in a direction parallel to the optical axis (O) from a pair of sides of the ring-shaped part ( 302 ) which are opposite to each other in the second direction (X). In this case, the first protruding part ( 122 ) of the base member ( 12 ) and the first U-shaped plate part ( 305 ) of the inner housing ( 30 ) are fitted to each other in a region around the first cutout part ( 202   a ) of the first plate part ( 202 F). In addition, the second protruding part ( 123 ) of the base member ( 12 ) and the second U-shaped plate part ( 306 ) of the inner housing ( 30 ) are fitted to each other in a region around the second cutout part ( 202   b ) of the second plate part ( 202 B). 
         [0214]    In the lens holder driving device ( 10 ;  10 A;  10 B), the lens holder driving device ( 10 ;  10 A;  10 B), preferably, the plate-shaped driving magnet pieces ( 182 ;  182 A) and the pair of sensor magnets ( 342   a ,  342   b ) are disposed at positions which are point symmetrical about the optical axis (O). 
         [0215]    The lens holder driving device ( 10 ;  10 A;  10 B) may further include a flexible printed circuit ( 40 ) attached on an exterior wall of the first protruding part ( 122 ) of the base member ( 12 ) at the first cutout part ( 202   a ) of the first plate part ( 202 F). In this case, preferably, the magnetic detection device ( 344 ) is attached on an internal surface side of the flexible printed circuit ( 40 ); and the flexible printed circuit ( 40 ) includes a light shielding film ( 404 ) configured to cover at least a portion which is opposite to the magnetic detection device ( 344 ) on an external surface side of the flexible printed circuit ( 40 ). The flexible printed circuit ( 40 ) may include a pair of cone-shaped depressions ( 401 ) that are recessed inward at both end portions in the first direction (Y). In this case, a pair of external connection terminals ( 244 - 1 ,  244 - 2 ) of the lower leaf spring ( 24 ) protrude and joined thereto by soldering in a state where the external connection terminals ( 244 - 1 ,  244 - 2 ) are housed in the pair of cone-shaped depressions ( 401 ) without protruding over a main surface of the flexible printed circuit ( 40 ). The flexible printed circuit ( 40 ) may have a grounding pattern ( 402   ag ) at a center portion on the external surface side thereof. In this case, preferably, the first plate part ( 202 F) of the yoke ( 20 ) has a protrusion part ( 207 ) protruding downward at the first cutout part ( 202   a ); the flexible printed circuit ( 40 ) is attached on an exterior wall of the first protruding part ( 122 ) of the base member ( 12 ) in a state where the flexible printed circuit ( 40 ) is inserted in the protrusion part ( 207 ); and the yoke ( 20 ) and the grounding pattern ( 402   ag ) are joined together by soldering at the protrusion part ( 207 ). Preferably, the protrusion part ( 207 ) is Sn-plated and half-punched. 
         [0216]    In the lens holder driving device ( 10 ;  10 A;  10 B), preferably, the ring-shaped upper end part ( 204 ) of the yoke ( 20 ) includes a semi-punched portion ( 204   a ) that is semi-punched at a plurality of portions on an inner periphery side of the ring-shaped upper end part ( 204 ). In this case, the upper leaf spring ( 22 ) makes contact with the plurality of semi-punched portions ( 204   a ) when the lens holder ( 14 ) moves upward. 
         [0217]    In the lens holder driving device ( 10 ;  10 A;  10 B), preferably, the vertical extending part ( 304 ) of the inner housing ( 30 ) has a protrusion ( 3042 ) protruding outward in a radial direction. In this case, the yoke ( 20 ) is fitted to the inner housing ( 30 ) in a lightly pressed state with the outer cylinder part ( 202 ) of the yoke ( 20 ) pushing down the protrusion ( 3042 ) of the inner housing ( 30 ) to thereby set a position of the yoke ( 20 ) with respect to the inner housing ( 30 ). Desirably, the protrusion ( 3042 ) has a substantially semi-columnar shape which extends in a direction parallel to the direction of the optical axis (O). Desirably, the protrusion ( 3042 ) has a top end portion ( 3042   a ) having a substantially half cone shape at an upper part thereof. 
         [0218]    According to a second exemplary mode of the present invention, a camera-equipped mobile terminal ( 80 ) in which the above-mentioned lens holder driving device ( 10 ;  10 A;  10 B) is installed can be obtained. 
         [0219]    It is to be noted that the reference numerals in parentheses are merely examples intended for convenience of description of the present invention, and the present invention is not limited thereto. 
         [0220]    While the invention made by the present inventor has been specifically described based on the preferred embodiments, it is not intended to limit the present invention to the above-mentioned preferred embodiments but the present invention may be further modified within the scope and spirit of the invention defined by the appended claims. 
         [0221]    This application is entitled to and claims the benefit of Japanese Patent Application No. 2014-160592 filed on Aug. 6, 2014, the disclosure each of which including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           10 ,  10 A,  10 B Lens holder driving device 
           11  Lens barrel 
           12  Base member (actuator base) 
           120  Base part 
           122  Front protruding part (first protruding part) 
           122   a  Rectangular hole 
           122   b  C plane 
           123  Rear protruding part (second protruding part) 
           14  Lens holder 
           140  Cylindrical part 
           140   a  Housing part 
           16  Driving coil 
           162  Long side part 
           164  Short side part 
           18 ,  18 A,  18 B Driving magnet 
           182 ,  182 A Plate-shaped driving magnet piece 
           182 Aa Substantially triangular prism shape protrusion part 
           184  Substantially triangular prism shape driving magnet piece 
           20  Yoke 
           202  Outer cylinder part 
           202   a  Front cutout part (first cutout part) 
           202   b  Rear cutout part (second cutout part) 
           202 F Front plate part (first plate part) 
           202 B Rear plate part (second plate part) 
           202 L Left plate part 
           202 R Right plate part 
           204  Ring-shaped upper end part 
           204   a  Semi-punched portion 
           206  Inner vertical extending part 
           207  Protrusion part 
           22  Upper leaf spring 
           222  Upper inner periphery end part 
           224  Upper outer periphery end part 
           226  Upper arm part 
           226   a  U-turn-shaped portion 
           24  Lower leaf spring 
           24 - 1  First spring piece 
           24 - 2  Second spring piece 
           242  Lower inner periphery end part 
           242 - 1  First terminal part 
           242 - 2  Second terminal part 
           244  Lower outer periphery end part 
           244 - 1  First external connection terminal 
           244 - 2  Second external connection terminal 
           246  Lower arm part 
           246   a  U-turn-shaped portion 
           247  Positioning protrusion 
           30  Spacer (inner housing) 
           302  Ring-shaped part 
           30  Four vertical extending parts 
           304  Two protrusions 
           3042   a  Top end portion 
           305  Front U-shaped plate part (first U-shaped plate part) 
           306  Rear U-shaped plate part (second U-shaped plate part) 
           34  Position detection part 
           342   a  Sensor magnet 
           342   b  Sensor magnet 
           344  Hole sensor (magnetic detection device) 
           40  Flexible printed circuit (FPC) 
           401  Cone-shaped depression 
           402  Base material 
           402   a  First conductor pattern 
           402   ag  Grounding pattern 
           402   b  Second conductor pattern 
           404  First cover film (light shielding film) 
           406  Second cover film 
           45  Elastic adhesive agent (stretchable and flexible resin) 
           52 ,  54  Solder 
           80  Camera-equipped mobile terminal (smartphone) 
         O Optical axis 
         X Front-rear direction (second direction) 
         Y Horizontal direction (first direction) 
         Z Vertical direction