Abstract:
The purpose of the present invention is to provide an actuator which can realize a further reduction in height. Provided is an actuator which performs shake correction by tilting a driven member using the drive force of a voice coil motor, wherein a support part tiltably supports a movable body with respect to a fixed body in which one from between a magnet part and a coil part is disposed on a base member, the movable body being configured so that the other from between the magnet part and the coil part is disposed on a frame-shaped retaining member on which the driven member is mounted. The retaining member has steps, and these steps enable a mounting site of the driven member to be closer to the base member than the disposition site of the one from between the coil part and the magnet part.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a hand-shake correction actuator, a camera module having a hand-shake correction function, and a camera-mounted device. 
       BACKGROUND ART 
       [0002]    In general, a small-sized camera module is mounted in mobile terminals such as smartphones. Such a module often has an auto-focusing function for automatically focusing at the time of capturing a subject and a hand-shake correction function (OIS: Optical Image Stabilization) for reducing irregularities of an image by correcting hand shake (vibration) caused at the time of capturing an image. 
         [0003]    As a hand-shake correction method, a module tilt method is known in which an imaging module is integrally tilted (for example PTL 1). The imaging module is a module having a lens part and an imaging device (for example, a charge coupled device (CCD)), which may be provided with an auto-focusing actuator. 
         [0004]    In the following descriptions, the auto-focusing actuator is referred to as “AF actuator,” and the hand-shake correction actuator is referred to as “OIS actuator.” 
         [0005]      FIG. 1  is an external view illustrating an exemplary camera module of a traditional module tilt type.  FIG. 2  is an exploded perspective view illustrating the exemplary camera module of a traditional module tilt type. 
         [0006]    As illustrated in  FIGS. 1 and 2 , camera module  2  of a traditional module tilt type includes fixing part  21 , movable part  22 , elastic supporting part  23 , imaging module  24 , and shake detection part  25 . An OIS actuator is composed of fixing part  21 , movable part  22 , and elastic supporting part  23 . 
         [0007]    Fixing part  21  includes base member  211 , coil part  212 , and OIS print wiring board  213 . Coil part  212  is disposed on base member  211 . OIS print wiring board  213  feeds power to coil part  212 , and outputs a detection signal of shake detection part  25  to a control part. 
         [0008]    Movable part  22  includes yoke  221 , magnet part  222 , top plate  223 , and module guide  224 . Yoke  221  and magnet part  222  are disposed in respective housing sections formed in top plate  223 . Module guide  224  is fixed to top plate  223 . Imaging module  24  is fixedly disposed in a space sandwiched between a pair of module guides  224 . 
         [0009]    Elastic supporting part  23  has a biaxial gimbal mechanism, and movable part  22  (top plate  223 ) is fixed to an outer gimbal. Elastic supporting part  23  is disposed at an approximate center of base member  211  in a floating fashion, and fixed by stopper  231 . Elastic supporting part  23  supports movable part  22  such that movable part  22  can rotationally sway around the X axis and the Y axis orthogonal to the optical axis (Z axis), that is, elastic supporting part  23  supports movable part  22  such that movable part  22  can be tilted. 
         [0010]    Shake detection part  25  is composed of a gyro sensor that detects the angular velocity of imaging module  24 , for example. Shake detection part  25  is fixed to a side surface of module guide  224  of movable part  22 . The detection signal of shake detection part  25  is output to the control part through OIS print wiring board  213  that constitutes fixing part  21 . 
         [0011]    An OIS voice coil motor (VCM) is composed of coil part  212  and magnet part  222 . That is, when a current flows through coil part  212 , a Lorentz force is generated at coil part  212  by interaction between the magnetic field of magnet part  222  and a current flowing through coil part  212  (Fleming&#39;s left hand rule). Since coil part  212  is fixed, a reactive force is exerted on magnet part  222 . This reactive force is the driving force of the OIS voice coil motor. Movable part  22  rotationally sways until the driving force of the OIS voice coil motor and the restoration force (returning force) of elastic supporting part  23  become equivalent to each other. In this manner, shift of the optical axis due to hand shake is corrected, and the orientation of the light axis is kept at an orientation. 
       CITATION LIST 
     Patent Literature 
     PTL 1 
       [0000]    
       
         Japanese Patent Application Laid-Open No. 2014-10287 
       
     
       SUMMARY OF THE INVENTION 
     Technical Problem 
       [0013]    In recent years, along with thickness reduction of mobile terminals, further height reduction of camera modules has been desired. However, the above-described traditional structure uses module guide  224 , stopper  231 , and the like for the purpose of positioning and fixation, and therefore further height reduction is difficult in the traditional structure. 
         [0014]    An object of the present invention is to provide an actuator, camera module, and camera-mounted device that can achieve further height reduction. In particular, this object is to provide an actuator, camera module, and camera-mounted device that can achieve further height reduction more surely by reason that a placement region for a driven part (for example, imaging module) is lowered. The present invention also intends to provide an actuator, camera module, and camera-mounted device in which it is possible to achieve height reduction and also to reduce the power consumption by improving the magnetic efficiency. 
       Solutions to Problems 
       [0015]    An actuator according to the present invention is configured to correct shake by tilting a driven part with a driving force of a voice coil motor including a coil part and a magnet part, and to include: a fixing part which includes a base member and in which one of the coil part and the magnet part is disposed on the base member peripherally with respect to the driven part; a movable part including a frame-shaped holding member having a surface which faces away from the base member and on which the driven part is placed, the movable part being a part in which the other one of the coil part and the magnet part is disposed peripherally with respect to the driven part on a surface of the holding member facing the base member; and a supporting part disposed to the base member, and configured to support the movable part such that the movable part is tiltable with respect to the fixing part, in which the holding member includes a step by which a placement region for the driven part is closer to the base member than a disposition region for the one of the coil part and the magnet part is to the base member. 
         [0016]    A camera module according to the present invention is configured to include: the above actuator; an imaging module including a lens part and an imaging device, and bonded to the holding member as the driven part; and a shake detection part that detects shake of the imaging module. 
         [0017]    A camera-mounted device according to the present invention is configured to be an information device or a transporting device, and to include the above camera module. 
       Advantageous Effects of Invention 
       [0018]    According to the present invention, the number of components is small in comparison with the traditional construction, and therefore it is possible to achieve further height reduction and facilitation of assembling processes. In particular, a placement region for a driven part (for example, imaging module) is lowered, and therefore further height reduction can be more surely achieved. In addition, it is possible to achieve height reduction, and also to reduce the power consumption by improving the magnetic efficiency since positions of coil and magnet parts are not restraint by the height reduction. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0019]      FIG. 1  is an external view illustrating an exemplary camera module of a traditional module tilt type; 
           [0020]      FIG. 2  is an exploded perspective view illustrating the exemplary camera module of a traditional module tilt type; 
           [0021]      FIGS. 3A and 3B  illustrate a smartphone in which a camera module according to an embodiment of the present invention is mounted; 
           [0022]      FIG. 4  is a perspective view of an external appearance of the camera module; 
           [0023]      FIG. 5  is an exploded perspective view of the camera module; 
           [0024]      FIG. 6  is a sectional view along the Y direction of the camera module; 
           [0025]      FIG. 7  is a sectional view along the X direction of the camera module; 
           [0026]      FIG. 8  is a bottom view of a yoke to which an elastic supporting part is attached; and 
           [0027]      FIG. 9A  is a front view of an automobile in which an onboard camera according to one embodiment of the invention is mounted, and  FIG. 9B  is a perspective view of the automobile in which the onboard camera is mounted. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0028]    In the following, an embodiment of the present invention is described in detail with reference to the drawings. 
         [0029]      FIGS. 3A and 3B  illustrate smartphone M in which camera module  100  according to an embodiment of the present invention is mounted.  FIG. 3A  is a front view of smartphone M, and  FIG. 3B  is a rear view of smartphone M. 
         [0030]    For example, smartphone M is provided with camera module  100  as a back side camera OC. Camera module  100  has an auto-focusing function and a hand-shake correction function, and can capture an image without image blurring by automatically performing focusing at the time of capturing a subject and by correcting hand shake (vibration) caused at the time of capturing an image. The hand-shake correction function of camera module  100  is of a module tilt type. The module tilt type is advantageous in that no deformation is caused at four corners of the screen. 
         [0031]      FIG. 4  is a perspective view of an external appearance of camera module  100 .  FIG. 5  is an exploded perspective view of camera module  100 .  FIG. 6  is a sectional view of camera module  100  along the Y direction.  FIG. 7  is a sectional view of camera module  100  along the X direction. In this respect,  FIGS. 6 and 7  particularly illustrate a magnetic circuit part that is a voice coil motor. 
         [0032]    Here, as illustrated in  FIG. 4  to  FIG. 7 , descriptions will be made with an orthogonal coordinate system (X, Y, Z). Camera module  100  is mounted such that the vertical direction (or horizontal direction) is the X direction, the horizontal direction (or vertical direction) is the Y direction, and the front-rear direction is the Z direction (optical axis direction) at the time of actually capturing an image with smartphone M. 
         [0033]    As illustrated in  FIG. 4  to  FIG. 7 , camera module  100  includes fixing part  11 , movable part  12 , elastic supporting part  13 , imaging module  14 , shake detection part  15 , displacement detection part  16 , and the like. OIS actuator A is composed of fixing part  11 , movable part  12 , and elastic supporting part  13 . In OIS actuator A, hand-shake correction is performed with use of the driving force of an OIS voice coil motor including coil part  112  and magnet part  122 . 
         [0034]    Fixing part  11  is fixed so as to be unmovable when mounted in smartphone M. Fixing part  11  supports movable part  12  via elastic supporting part  13  such that movable part  12  is movable. Fixing part  11  includes base member  111 , coil part  112 , OIS print wiring board  113 , skirt member (cover member)  114 , main body cover member (hereinafter referred to as “cover member”)  115 , and print circuit board  117 . 
         [0035]    Base member  111  is a member formed of a metal material in a substantially rectangular shape, and is disposed on print circuit board  117 . Base member  111  is formed of a metal, and as a result the strength is high in comparison with the case where base member  111  is formed of a resin. Thus the thickness of base member  111  can be reduced, and in turn, reduction of the height of camera module  100  can be achieved. 
         [0036]    Base member  111  includes, at the center thereof, protruding part  111   a  having a truncated pyramid shape for fixing elastic supporting part  13 . Base member  111  includes, at positions around protruding part  111   a,  power feeding parts  111   b  in the form of pads for supplying electricity to coil part  112 . In base member  111 , displacement detection parts  16  are disposed in cutout regions  111 C provided at positions around protruding part  111   a  other than the positions of power feeding parts  111   b.    
         [0037]    Displacement detection part  16  is composed of a Hall device or the like, for example, and detects tilt of movable part  12 , in particular, an offset of imaging module  14  due to its dead weight (dead weight sagging) when movable part  12  is attached to fixing part  11  via elastic supporting part  13 , or detects an offset of imaging module  14  due to the reactive force of the FPC when imaging module  14  is attached to fixing part  11 . In this manner, camera module  100  detects and corrects an offset position of imaging module  14  by means of displacement detection part  16 , so that imaging module  14  can be precisely disposed without being tilted at the reference position for detection by shake detection part  15 . 
         [0038]    In addition, base member  111  includes, at the middle portions of four sides constituting the peripheral edge of base member  111 , protruding side portions  1111  for positioning cover member  115  and skirt member  114  during fixation thereof. Protruding side portions  1111  are respectively engaged with cutouts  1141  and  1151  of skirt member  114  and cover member  115  when skirt member  114  and cover member  115  are attached to base member  111 . In particular, by virtue of engagement of cutout  1141  with protruding side portion  1111 , skirt member  114  is fit at the outside of the peripheral edge of base member  111  to be fixedly positioned. As for cover member  115 , cutout  1151  is engaged with protruding side portion  1111  of base member  111 , and cover member  115  is fit at the outside of the outer peripheral surface of skirt member  114 . In this way, cover member  115  are also positioned by means of protruding side portions  1111  of base member  111 . 
         [0039]    Coil part  112  is composed of four tilt coils  112 A to  112 D and is disposed at base member  111  to surround protruding part  111   a.  Coil part  112  (tilt coils  112 A to  112 D) is disposed such that the winding axis of each coil is oriented in the direction in which base member  111  and yoke (holding member)  120  face each other (in this case, in the Z direction). Power is fed to coil part  112  (tilt coils  112 A to  112 D) through power feeding parts  111   b.    
         [0040]    Tilt coils  112 A and  112 C face each other in the X direction, and tilt coils  112 A and  112 C are used to rotationally sway movable part  12  around the Y axis. Tilt coils  112 B and  112 D face each other in the Y direction, and tilt coils  112 B and  112 D are used to rotationally sway movable part  12  around the X axis. 
         [0041]    OIS print wiring board  113  includes a power-source line (not illustrated) for feeding power to coil part  112 . OIS print wiring board  113  is fixed on the bottom surface of base member  111 , and the power-source line is electrically connected with power feeding parts  111   b  of base member  111 . 
         [0042]    Skirt member  114  is a frame-shaped member composed of four walls  114   b  coupled with each other in a rectangular shape, and includes reception port  114   a  for imaging module  14 . Skirt member  114  includes cutouts  1141  at positions corresponding to protruding side portions  1111  of base member  111 , that is, at respective middle portions of lower ends of walls  114   b  of skirt member  114 . Skirt member  114  includes, at upper portions of respective walls  114   b,  restriction parts  114   d  that slightly protrude from the respective upper portions toward the inside and form a rectangular frame, and restriction parts  114   d  prevent movable part  12  disposed in the frame, that is, in reception port  114   a  of skirt member  114  from being excessively tilted. 
         [0043]    After movable part  12  is attached to base member  111  through elastic supporting part  13 , skirt member  114  is fixed by being fit at the outside of the peripheral edge of base member  111 . Movable part  12  is set between base member  111  and skirt member  114 . 
         [0044]    Cover member  115  is a capped rectangular cylindrical member, which includes opening  115   a  in the cap at the top surface of the cylindrical member. Opening  115   a  in cover member  115  allows lens part  141  of imaging module  14  to face outside. Cover member  115  includes, at the lower end of its cylindrical peripheral wall, cutouts  1151  formed at positions corresponding to protruding side portions  1111  of base member  111 . 
         [0045]    After imaging module  14  is mounted to OIS actuator A, cover member  115  is fit at the outside of skirt member  114  and cutouts  1151  are engaged with protruding side portions  1111  of base member  111 , so that cover member  115  is fixed to base member  111 . Drawing port  115   b  for imaging-module print wiring board  143  to be pulled to the outside is formed at one side surface of cover member  115 . A part of one side surface of cover member  115  is processed so as to form outwardly projecting hood part  115   c,  and drawing port  115   b  is thus formed below hood part  115   c.    
         [0046]    Movable part  12  rotationally sways around the X axis and the Y axis with respect to fixing part  11 . Movable part  12  includes yoke (holding member)  120 , magnet part  122 , and positioning plate  126 . When imaging module  14  is mounted to OIS actuator A, yoke  120  directly holds imaging module  14 . Imaging module  14  is bonded on the top surface of yoke  120  with a double-sided tape, resin adhesive agent, or the like, for example. With this construction, even without using positioning members such as the module guide disclosed in PTL 1, imaging module  14  can be fixed to yoke  120  with use of a jig while setting the position of imaging module  14  with high accuracy. 
         [0047]    Yoke  120  is a rectangular frame-shaped member formed of a magnetic material, and includes rectangular frame-shaped yoke main body  121  (holding-part main body) and flat frame-shaped holding frame portion  1211  that is provided inside the frame shape of yoke main body  121  and fixes imaging module  14 . 
         [0048]    Yoke main body  121  includes flat frame-shaped top plate portion  121   a  composed of four flat plates which are coupled with each other in a rectangular shape. Magnet part  122  is fixed on the underside of top plate portion  121   a.  Yoke main body  121  includes outside droop portion  121   b  along the outer peripheral edge of top plate portion  121   a  (in particular, outer edge of each flat plate composing top plate portion  121   a ), outside droop portion  121   b  being formed in such a manner as to downwardly protruding and droop down. In addition, yoke main body  121  includes inside droop portion  121   c  along the inner peripheral edge of top plate portion  121   a  (in particular, inner edge of each flat plate composing top plate portion  121   a ), inside droop portion  121   c  being formed in such a manner as to downwardly protruding and droop down. That is, the cross-sectional shape of one side of yoke main body  121  has a recessed shape open toward base member  111 , that is, a downwardly open U-shape. Top plate portion  121   a  that forms the bottom surface inside this recessed shape is located more distant from base member  111  than holding frame portion  1211  is from base member  111 . In addition, the outer peripheral edge of holding frame portion  1211  is connected to the lower end of inside droop portion  121   c  of yoke main body  121 . The bottom surface of imaging module  14  is fixed on the top surface of holding frame portion  1211  (a part of the top surface of yoke  120 ) with a double-sided tape or resin adhesive agent. 
         [0049]    As described above, in yoke  120 , top plate portion  121   a  of yoke main body  121  to which magnet part  122  is fixed is located, by way of inside droop portion  121   c,  more peripherally and higher than holding frame portion  1211  on which imaging module  14  is fixed. That is, top plate portion  121   a  is disposed at a position around holding frame portion  1211  and more distant from base member  111  than holding frame portion  1211  is from base member  111  in the Z direction. 
         [0050]    With this construction, a step by which holding frame portion  1211  is closer to base member  111  than top plate portion  121   a  is to base member  111  is formed between holding frame portion  1211  and top plate portion  121   a,  and a recessed portion is formed in the center of entire yoke  120 , in which imaging module  14  is fixed. 
         [0051]    Magnet part  122  is composed of four cuboid permanent magnets  122 A to  122 D corresponding to tilt coils  112 A to  112 D. Electromagnets may be used in place of permanent magnets. Permanent magnets  122 A to  122 D have a size which can be put inside tilt coils  112 A to  112 D. 
         [0052]    Permanent magnets  122 A to  122 D are disposed at the undersides of respective flat plates of yoke  120  such that the magnetization direction is the Z direction, and permanent magnets  122 A to  122 D are fixed by bonding, for example. In this case, permanent magnets  122 A to  122 D are fixed via positioning plate  126  formed in such a manner as to allow permanent magnets  122 A to  122 D to be disposed at predetermined positions. Positioning plate  126  is formed of a magnetic or non-magnetic material, has a shape corresponding to the shape of the underside of top plate portion  121   a,  and is provided with four slits at positions to which permanent magnets  122 A to  122 D are disposed. Positioning plate  126  is fixed to the underside of top plate portion  121   a  with a double-sided tape, adhesive agent, or the like, and permanent magnets  122 A to  122 D are fitted in the respective slits of positioning plate  126  in such a manner as to make contact with the underside of top plate portion  121   a.  In this manner, permanent magnets  122 A to  122 D are positioned and fixed with respect to yoke  120  with high precision (see  FIGS. 6 to 8 ). 
         [0053]    In addition, permanent magnets  122 A to  122 D are located between inside droop portion  121   c  and outside droop portion  121   b  of yoke  120 . In this case, permanent magnets  122 A to  122 D face both of inside droop portion  121   c  and outside droop portion  121   b,  at which permanent magnets  122 A to  122 D are spaced apart from both of inside droop portion  121   c  and outside droop portion  121   b.    
         [0054]    Coil part  112  is located between magnet part  122  and yoke  120  (in particular, yoke main body  121 ) (see  FIGS. 5 and 6 ). Magnet part  122  is located on the winding axis of winding of coil part  112 . The central portion of coil part  112  are opened along the bonding direction of imaging module  14 , and magnet part  122  and coil part  112  are respectively disposed to yoke  120  and base member  111  such that magnet part  122  protrudes to the central portion of coil part  112 . 
         [0055]    To be more specific, tilt coils  112 A to  112 D are located between outside droop portion  121   b  and permanent magnets  122 A to  122 D and between inside droop portion  121   c  and permanent magnets  122 A to  122 D. In this manner, the periphery of coil part  112  is covered with yoke  120 , so that it is possible to prevent the AF actuator  142  of imaging module  14  from being unfavorably influenced by the magnetic field of the energization current of coil part  112 . 
         [0056]    In addition, magnet part  122  and coil part  112 , namely the magnetic circuit part including magnet part  122  and coil part  112  are located peripherally with respect to the lower end of imaging module  14  and holding frame portion  1211  (in particular, farther in the X and Y directions). In other words, the magnetic circuit part including magnet part  122  and coil part  112  is not disposed directly below the lower end of imaging module  14  and holding frame portion  1211 . That is, magnet part  122  (permanent magnets  122 A to  122 D) and coil part  112  (tilt coils  112 A to  112 D) are disposed on base member  111  peripherally with respect to the lower end of imaging module  14  and holding frame portion  1211  of yoke  120  in the X and Y directions. 
         [0057]    Elastic supporting part  13  is composed of a rectangular member having a biaxial gimbal mechanism (so-called gimbal spring).  FIG. 8  is a bottom view of a yoke to which an elastic supporting part is attached, and serves to explain the elastic supporting part. 
         [0058]    As illustrated in  FIG. 8 , elastic supporting part  13  includes center portion  13   a  and outer gimbal  13   c  continuously connected with center portion  13   a  with inner gimbal  13   b  therebetween. Outer gimbal  13   c  rotationally sways around the X axis and the Y axis. It is to be noted that the gimbals that are elastic supporting part  13  are indicated by hatching in an attempt to differentiate them from the other components in  FIG. 8 . As illustrated in  FIG. 8 , center portion  13   a  has a rectangular frame shape, and inner gimbal  13   b  has a complex curved shape. Here, outer gimbal  13   c  includes two long plates, which are respectively arranged outside and in parallel with a pair of side portions of center portion  13   a  that face each other. Outer gimbal  13   c  is connected to one end of inner gimbal  13   b  at the middle of outer gimbal  13   c.  In the meantime, the other end of the inner gimbal is connected to center portion  13   a.    
         [0059]    Center portion  13   a  of elastic supporting part  13  is fit at the outside of protruding part  111   a  of base member  111  and bonded or welded thereto. As a result, a peripheral portion with respect to center portion  13   a  of elastic supporting part  13  is located in such a manner as to be spaced apart from the top surface of base member  111  by a predetermined distance, as illustrated in  FIG. 7 . In this respect, this predetermined distance represents a range in which elastic supporting part  13  is movable when elastic supporting part  13  rotationally moves around the central axes in the X and Y directions that are directions in which elastic supporting part  13  is movable. In addition, as illustrated in  FIG. 8 , outer gimbal  13   c  of elastic supporting part  13  is bonded or welded to a pair of parallel side portions on the underside of holding frame portion  1211  of yoke  120 . In this manner, movable part  12  is disposed at an approximate center of base member  111  in a floating fashion, and thus can rotationally sway around the X axis and the Y axis. Since elastic supporting part  13  is fixed to base member  111  by bonding, it is not necessary to provide lock members such as the stopper disclosed in PTL  1 . Elastic supporting part  13  is attached via outer gimbal  13   c  to the underside of holding frame portion  1211 , on the top surface of which imaging module  14  is bonded. Accordingly, the distance in the Z direction between elastic supporting part  13  and imaging module  14  substantially corresponds to the thickness of holding frame portion  1211 . In this way, the length in the Z direction of camera module  100  itself can be reduced, that is, the height reduction of camera module  100  can be achieved. 
         [0060]    Imaging module  14  includes lens part  141 , an imaging device (not illustrated), AF actuator  142 , and imaging-module print wiring board  143 . 
         [0061]    The imaging device (not illustrated) is composed of, for example, a CCD (charge coupled device) image sensor, a CMOS (complementary metal oxide semiconductor) image sensor, or the like. The imaging device (not illustrated) is mounted to imaging-module print wiring board  143 . The imaging device (not illustrated) captures a subject image imaged by lens part  141 . 
         [0062]    AF actuator  142  includes an AF voice coil motor for example, and moves lens part  141  in the light axis direction by utilizing the driving force of AF voice coil motor. Publicly known techniques can be applied to AF actuator  142 . 
         [0063]    Imaging-module print wiring board  143  is here composed of flexible printed circuits having flexibility. Imaging-module print wiring board  143  includes a power-source line (not illustrated) configured to feed power to a coil part (not illustrated) of AF actuator  142 , and a video signal line (not illustrated) for video signals output from the imaging device, and a detection signal line (not illustrated) for detection signals output from shake detection part  15 . As illustrated in  FIG. 7 , imaging-module print wiring board  143  is pulled to the outside through drawing port  115   b  of cover member  115  from the inside of skirt member  114  and over skirt member  114  in the state where imaging module  14  is mounted in OIS actuator A. To be more specific, imaging-module print wiring board  143  extends out upwardly from the underside of imaging module  14 , is bent to extend outwardly of a skirt portion, and then extends out from drawing port  115   b  of cover member  115 . Imaging-module print wiring board  143  as pulled out is connected to print circuit board  117  of fixing part  11 . As described above, imaging-module print wiring board  143  is flexible, and therefore does not disturb the movement of movable part  12  although imaging-module print wiring board  143  is provided in movable part  12 . In the meantime, branching may be provided in imaging-module print wiring board  143  to equip the video signal line and the detection signal line with different connectors. 
         [0064]    Shake detection part  15  detects shake (movement) of imaging module  14 . Shake detection part  15  is composed of a gyro sensor that detects the angular velocity of imaging module  14 , for example. Shake detection part  15  is mounted to upright part  143   a  of imaging-module print wiring board  143 . The detection signal of shake detection part  15  is output to a control part through imaging-module print wiring board  143 . The control part controls the energization current of coil part  112  based on the detection signal. In this respect, the control part (not illustrated) may be mounted on imaging-module print wiring board  143  or on print circuit board  117 . In addition, a control part mounted on smartphone M may be utilized via the print wiring board. 
         [0065]    In traditional camera module  2  (see  FIGS. 1 and 2 ), shake detection part  25  is attached to movable part  22  (module guide  224 ), and the detection signal of shake detection part  25  is output through OIS print wiring board  213  serving as fixing part  21 . The rotational sway of movable part  22  is inhibited by OIS print wiring board  213 , and the sensitivity of the tilt operation is reduced, and as a result, the driving force of the OIS actuator is inevitably increased. 
         [0066]    In contrast, in camera module  100  according to the embodiment, the detection signal of shake detection part  15  is output through imaging-module print wiring board  143  of imaging module  14 . That is, OIS print wiring board  113  of fixing part  11  does not inhibit the rotational sway of movable part  12  (imaging module  14 ). Accordingly, the driving force of OIS actuator A can be reduced in comparison with the traditional technique, and the power consumption can be reduced. In addition, OIS print wiring board  113  of fixing part  11  is used only for power feeding to coil part  112 , and therefore may be omitted by separately providing another power-source line. Consequently, cost reduction and space-saving can be achieved. 
         [0067]    In OIS actuator A, coil part  112  and magnet part  122  constituting the magnetic circuit part of the OIS voice coil motor are disposed at positions surrounding imaging module  14  that is an object to be moved. In particular, the magnetic circuit part including magnet part  122  (permanent magnets  122 A to  122 D) and coil part  112  (tilt coils  112 A to  112 D) is disposed on base member  111  peripherally with respect to the lower end of imaging module  14  and holding frame portion  1211  of yoke  120  in the X and Y directions. 
         [0068]    The magnetic circuit part is disposed at such a position that a part of the magnetic circuit part is superimposed on the lower end of imaging module  14  and holding frame portion  1211  of yoke  120  when viewed in the X and Y directions. In other words, the magnetic circuit part is disposed at such a position that one of magnet part  122  and coil part  112  (in this case, magnet part  122 ) is superimposed on the lower end of imaging module  14  and holding frame portion  1211  of yoke  120  when viewed in the X and Y directions. 
         [0069]    In the magnetic circuit part, permanent magnets  122 A to  122 D constituting magnet part  122  are disposed above tilt coils  112 A to  112 D constituting coil part  112  and in such a manner as to be partially inserted inside tilt coils  112 A to  112 D. In this manner, permanent magnets  122 A to  122 D are disposed above respective tilt coils  112 A to  112 D along the winding axes directions of respective tilt coils  112 A to  112 D (Z direction). In addition, magnet part  122  and coil part  112  are disposed peripherally with respect to the lower end of imaging module  14  and holding frame portion  1211  of yoke  120  in the X and Y directions and at such a position that a part of the magnetic circuit part is superimposed on the lower end of imaging module  14  and holding frame portion  1211  of yoke  120 . 
         [0070]    In the OIS voice coil motor including magnet part  122  and coil part  112  disposed as described above, in an initial state where no current flows through coil part  112 , imaging module  14  (movable part  12 ) is held at a neutral position where the optical axis coincides with the Z direction. In this respect, in a case where imaging module  14  (movable part  12 ) is offset from the neutral position due to dead weight sagging or the like when movable body  12  is attached to fixing part  11 , an offset position detected by displacement detection part  16  is corrected to the neutral position where the optical axis coincides with the Z direction. 
         [0071]    When a current flows through coil part  112 , a Lorentz force in the Z direction is generated at coil part  112  by interaction between the magnetic field of magnet part  122  and the current flowing through coil part  112  (Fleming&#39;s left hand rule). Since coil part  112  is fixed, a reactive force is exerted on magnet part  122  that is movable part  12 . This reactive force is the driving force of the OIS voice coil motor. 
         [0072]    To be more specific, when opposite currents are supplied to tilt coils  112 A and  112 C facing each other in the X-axis direction, opposite forces in the Z direction act on permanent magnets  122 A and  122 C. Accordingly, movable part  12  including imaging module  14  rotationally sways around the Y axis with center portion  13   a  of elastic supporting part  13  as a fulcrum. Likewise, when opposite currents are supplied through tilt coils  112 B and  112 D facing each other in the Y-axis direction, movable part  12  including imaging module  14  rotationally sways around the X axis with center portion  13   a  of elastic supporting part  13  as a fulcrum. Movable part  12  rotationally sways until the driving force of the OIS voice coil motor (force which acts on magnet part  122 ) and the restoration force of elastic supporting part  13  become equivalent to each other. 
         [0073]    At this time, the energization current of coil part  112  is controlled based on the detection result of shake detection part  15  such that rotational sway of movable part  12  offsets shake of imaging module  14 . In this manner, shift of the optical axis due to hand shake is corrected, and the orientation of the light axis is kept at an orientation. 
         [0074]    In addition, since restriction part  114   d  of skirt member  114  limits the rotational sway of movable part  12 , it is possible to prevent movable part  12  from being excessively rotationally swayed by the drop impact or the like. 
         [0075]    In addition, the bottom surface of imaging module  14  is fixed to the top surface of holding frame portion  1211  of movable part  12  (part of the top surface of yoke  120 ) with a double-sided tape or resin adhesive agent. Holding frame portion  1211  is connected on the peripheral side thereof to top plate portion  121   a  of yoke main body  121  by way of inside droop portion  121   c  of yoke main body  121 , top plate portion  121   a  being located at a position more distant from base member  111  in the Z direction than from holding frame portion  1211 , that is, at a higher position than from holding frame portion  1211 . Magnet part  122  is fixed to the underside of top plate portion  121   a,  and coil part  112  is disposed with respect to magnet part  122  such that when viewed in the Z direction coil part  112  is spaced apart from magnet part  122  and magnet part  122  is located inside coil part  112 . The magnetic circuit part including magnet part  122  and coil part  112  is disposed peripherally with respect to holding frame portion  1211  (outwardly in the X and Y directions), in other words, peripherally with respect to imaging module  14 . In this case, magnet part  122  and coil part  112  are located outside of the range in which imaging module  14  is movable. 
         [0076]    In addition, in yoke  120 , magnet part  122  is fixed on the underside of top plate portion  121   a  that is arranged at a height level higher than the height level of holding frame portion  1211 . That is, magnet part  122  is located peripherally with respect to and higher than holding frame portion  1211  on which imaging module  14  is fixed. 
         [0077]    As described above, the magnetic circuit part including magnet part  122  (permanent magnets  122 A to  122 D) and coil part  112  (tilt coils  112 A to  112 D) is disposed on base member  111  peripherally with respect to the lower end of imaging module  14  or holding frame portion  1211  of yoke  120  in the X and Y directions. In other words, the magnetic circuit part is not disposed in a space between base member  111  and imaging module  14  in which the height (in the Z direction) is limited. 
         [0078]    In addition, in movable part  12 , yoke  120  includes in the center thereof the recessed portion defined by yoke main body  121  (in particular, inside droop portion  121   c ) and holding frame portion  1211 , and imaging module  14  is fixed within this recessed portion. 
         [0079]    Actuator A corrects shake by tilting the driven part (imaging module  14 ) with the driving force of the voice coil motor including magnet part  122  and coil part  112  disposed as mentioned above. Actuator A includes: movable part  12  including frame shaped yoke  120  (holding member) on which the driven part (imaging module  14 ) is bonded, in which magnet part  122  is disposed to yoke main body  121  of yoke  120  (part of the holding member); fixing part  11  including base member  111  and frame shaped skirt member  114  fixed at the peripheral edge of base member  111 , in which coil part  112  is disposed to base member  111 ; and elastic supporting part (supporting part)  13  disposed to base member  111  and configured to support movable part  12  such that movable part  12  can be tilted with respect to fixing part  11 . Movable part  12  is set between base member  111  and skirt member  114 . With actuator A, the number of components is reduced in comparison with the traditional construction, and consequently further height reduction and facilitation of assembling processes are achieved. In addition, camera module  100  is simply obtained by only bonding imaging module  14  with an auto-focusing function to yoke  120 . 
         [0080]    In addition, according to the embodiment of the present invention, actuator A includes: fixing member  11  including base member  111 , in which one of coil part  112  and magnet part  122  is disposed on base member  111  peripherally with respect to the driven part (imaging module  14 ); movable part  12  including the frame shaped holding member (yoke  120 ) on a surface (top surface) of which facing away from base member  111  the driven part is placed, in which the other one of coil part  112  and magnet part  122  is disposed peripherally with respect to the driven part on a surface (underside) of the holding member facing base member  111 ; and the supporting part (elastic supporting part)  13  disposed to base member  111  and configured to support movable part  12  such that movable part  12  can be tilted with respect to fixing part  11 . The holding member includes a step by which a placement region (holding frame portion  1211 ) for the driven part is closer to base member  111  than a disposition region (top plate portion  121   a ) for one of coil part  112  and magnet part  122  is to base member  111 . With this actuator A, the placement region in yoke  120  for imaging module  14  can be lower than the disposition region for coil part  112  or magnet part  122 , and therefore further height reduction can be more surely achieved. At the same time, the height of the magnetic circuit part, that is, the lengths of coil part  112  and magnet part  122  are not limited, and accordingly a decrease in the magnetic efficiency and an accompanying increase in the power consumption are not caused. That is, it is possible to secure the space in the height direction required for construction of the magnetic circuit part by utilizing room that is peripheral with respect to imaging module  14 , and accordingly the construction of the magnetic circuit part itself can be enlarged in the height direction. For example, the height (length in the Z direction) of coil part  112  can be greater by increasing the number of turns of coil part  112  (tilt coils  112 A to  112 D), or the length in the Z direction of magnet part  122  (permanent magnets  122 A to  122 D) can be increased. In this way, the magnetic force can be greater, so that it is possible to improve the magnetic efficiency and/or to reduce the power consumption. 
         [0081]    In addition, coil part  112  (tilt coils  112 A to  112 D) is disposed such that the winding axis of coil part  112  (tilt coils  112 A to  112 D) is oriented in the direction in which base member  111  and holding member (yoke)  120  face each other. Magnet part  122  (permanent magnets  122 A to  122 D) is disposed in such a manner as to protrude to the central portion of coil part  112  (tilt coils  112 A to  112 D). In this manner, coil part  112  and magnet part  122  can be enlarged in the height direction (Z direction) without coil part  112  and magnet part  122  being enlarged peripherally (in the X and Y directions). In this way, the construction of the magnetic circuit part itself can be enlarged without the disposition space in actuator A for the magnetic circuit part itself being enlarged. 
         [0082]    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. 
         [0083]    For example, while the actuator of the embodiment is of a so-called moving magnet type in which fixing part  11  includes coil part  112  and movable part  12  includes magnet part  122 , the present invention may be applied to an actuator of a so-called moving coil type in which a fixing part includes a magnet part and a movable part includes a coil part. In this case, a yoke is also disposed to the fixing part. 
         [0084]    While, in the embodiment, two pairs of tilt coil  112 A and permanent magnet  122 A and tilt coil  112 C and permanent magnet  122 C are disposed as the voice coil motor that rotationally sways movable part  12  around the X axis, and two pairs of tilt coil  112 B and permanent magnet  122 B and tilt coil  112 D and permanent magnet  122 D are disposed as the voice coil motor that rotationally sways movable part  12  around the Y axis, it suffices that at least one pair is disposed as each of the voice coil motors. 
         [0085]    In addition, photo reflectors, magnetic sensors, inductance detection with a coil, strain sensors, or the like may also be adopted as shake detection part  15  instead of gyro sensors. In the case where a detection device (for example a photodetector of a photo reflector, a Hall device of a magnetic sensor or the like) is disposed to the movable part, it is preferable to output a detection signal through a print wiring board of an imaging module. 
         [0086]    In addition, preferably, each component (in particular, magnet part  122 ) of actuator A is formed of a highly heat-resistant material. Soldering of a reflow type can thus be employed. In addition, as a countermeasure against noise, a conductive shield case may be provided on the outside of camera module  100 . 
         [0087]    While a smartphone that is a camera-equipped mobile terminal is described in the embodiment as an example of the camera-mounted device having camera module  100 , the present invention is also applicable to a camera-mounted device that is an information device or transporting device. For example, the present invention is also applicable to camera-equipped mobile phones, note-type personal computers, tablet terminals, mobile game machines, web cameras, and the like as a camera-mounted device. The present invention is also applicable to automobiles, camera-equipped onboard devices (for example, rear monitoring device or drive recorder), or the like as a camera-mounted device.  FIGS. 9A and 9B  illustrate vehicle C in which onboard camera module VC (Vehicle Camera) is mounted.  FIG. 9A  is a front view of vehicle C and  FIG. 9B  is a rear perspective view of vehicle C. Camera module  100  as described in the embodiment is mounted on vehicle C as onboard camera module VC, for example. Onboard camera module VC is used for rear monitoring, drive recording, collision avoidance control, automatic drive control, and the like. 
         [0088]    The embodiment disclosed herein is merely an exemplification in every respect and should not be considered as limitative. The scope of the present invention is specified by the following claims, not by the above-mentioned description. The scope of the present invention is intended to include all modifications in so far as they are within the scope of the appended claims or the equivalents thereof. 
         [0089]    This application is entitled to and claims the benefit of Japanese Patent Application No. 2014-260694 dated Dec. 24, 2014, the disclosure of which including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
       INDUSTRIAL APPLICABILITY 
       [0090]    The actuator, camera module, and camera-mounted device according to the present invention have an advantage that further height reduction can be achieved, and the actuator, camera module, and camera-mounted device are useful as a device applicable to information devices including mobile terminals such as smartphones, transporting devices such as automobiles, onboard camera-equipped devices, and the like. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           100  Camera module 
           11  Fixing part 
           12  Movable part 
           13  Elastic supporting part (supporting part) 
           13   a  Center portion 
           13   b  Inner gimbal 
           13   c  Outer gimbal 
           14  Imaging module (driven part) 
           15  Shake detection part 
           16  Displacement detection part 
           111  Base member 
           111   a  Protruding part 
           112  Coil part 
           112 A,  112 B,  112 C,  112 D Tilt coils 
           113  OIS print wiring board 
           114  Skirt member (cover member) 
           114   a  Reception port 
           114   d  Restriction part 
           115  Cover member 
           115   a  Opening 
           120  Yoke (holding member) 
           121  Yoke main body (holding-part main body) 
           121   a  Top plate portion (disposition region) 
           121   b  Outside droop portion 
           121   c  Inside droop portion 
           122  Magnet part 
           122 A,  122 B,  122 C,  122 D Permanent magnets 
           141  Lens part 
           142  AF actuator 
           143  Imaging-module print wiring board 
           1211  Holding frame portion (placement region)