Patent Publication Number: US-2021165239-A1

Title: Optical Member Driving Device, Camera Device and Electronic Apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Chinese patent applications CN201911221781.6 and CN201911220580.4, each filed on Dec. 3, 2019, the contents of which are incorporated by reference herein. 
     TECHNICAL FIELD 
     The present disclosure relates to an optical member driving device used in electronic apparatus such as smartphones, a camera device, and an electronic apparatus. 
     BACKGROUND 
     In a camera device equipped with an OIS (Optical Image Stabilizer) function, a SMA (Shape Memory Alloy) wire is provided between a movable member that holds the optical member and a support member that supports the movable member. By the expansion and contraction of the SMA wire, the movable member and the support member are relatively moved. As a document disclosing a technique related to this type of camera device, International Publication WO2018/129185A (hereinafter referred to as “Patent Document 1”) can be given. The suspension assembly described in Patent Document 1 includes a movable member which is a plate body made of stainless steel, and a support member which is a plate body having a wiring portion made of FPC (Flexible Printed Circuits)provided on the base. The movable member and the support member are arranged so as to face each other with a bearing sandwiched therebetween, and have crimp portions at corners in the diagonal direction of the support member and corners in the diagonal direction of the movable member which intersects the diagonal direction of the support member. An SMA wire is laid between the crimp portion of the movable member and the crimp portion of the support member. 
     SUMMARY 
     However, in the technique of Patent Document 1, the wiring portion on the base of the support member extends to the crimp portion at the corner, and at the crimp portion, the constitution is adopted in which the SMA wire is crimped together with the wiring portion to fix the SMA wire. Therefore, there is a problem that the fixing strength of the SMA wire is weak. 
     The present disclosure has been made in view of such a problem, and one of objects of the present disclosure is to provide an optical member driving device, a camera device, and an electronic apparatus, in which an SMA wire can be fixed with sufficient strength. 
     In accordance with a first aspect of the present disclosure, there is provided an optical member driving device including: a base; an FPC fixed on the base; a lower crimp plate fixed on the FPC; an upper crimp plate sliding on the lower crimp plate; and a plurality of SMA wires fixed to the lower crimp plate and the upper crimp plate at both ends, wherein the lower crimp plate includes a plurality of plate pieces having one crimp portion, and each of the plate pieces is fixed on the FPC in separation from each other and is electrically connected to the FPC. 
     In accordance with a second aspect of the present disclosure, there is provided a camera device including the optical member driving device described above. 
     In accordance with a third aspect of the present disclosure, there is provided an electronic apparatus comprising the camera device described above. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a front view of a smartphone which is an electronic apparatus mounted with a camera device including an OIS lens driving device which is an optical member driving device, according to one embodiment of the present disclosure; 
         FIG. 2  is a perspective view of the camera device of  FIG. 1 ; 
         FIG. 3  is a perspective view of the OIS lens driving device of  FIG. 2 ; 
         FIG. 4  is an exploded perspective view of the OIS lens driving device of  FIG. 2 ; 
         FIG. 5A  is a view of a portion of the upper crimp plate  5  of the OIS lens driving device of  FIG. 2  as viewed from an oblique lower side; 
         FIG. 5B  is a cross-sectional view of abutting portions of the protruding portion of the upper crimp plate and the third plate piece of the lower crimp plate; and 
         FIG. 5C  is a view of portions of the upper crimp plate and the lower crimp plate as viewed from an oblique upper side. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments of the present disclosure are explained with reference to drawings. As shown in  FIG. 1 , the camera device  1  is accommodated in the housing of the smartphone  99 . The camera device  1  includes: a lens body  8  which is an optical member; an image sensor  90  that photoelectrically converts light incident from a subject via the lens body  8 ; an AF (Autofocus) actuator  80  that drives the lens body  8  in a direction along an optical axis; an OIS lens driving device  2  that drives the AF actuator  80  in a plane orthogonal to the optical axis; and a case  98  that covers these members. The lens body  8 , which is an optical member, is driven by the OIS lens driving device  2  in an in-plane direction orthogonal to the optical axis. 
     Hereinafter, the optical axis direction along the optical axis of the lens body  8  is appropriately referred to as a Z direction, one direction orthogonal to the Z direction is appropriately referred to as an X direction and a direction orthogonal to both the Z direction and the X direction is appropriately referred to as a Y direction. Further, the +Z side of the optical axis of the lens body  8 , which is the side of the subject, may be referred to as an upper side, and the −Z side, which is the side on which the image sensor  90  on the opposite side of the subject is provided, may be referred to as a lower side. 
     As shown in  FIG. 4 , the OIS lens driving device  2  includes a base  3 , a lower crimp plate  4  fixed on the base  3 , an upper crimp plate  5  sliding on the lower crimp plate  4 , and four SMA wires  6  fixed to the lower crimp plate  4  and the upper crimp plate  5  at both ends. The details of the configuration of each portion will be described below. 
     The base  3  has a thin rectangular shape. A perfect circle-shaped through hole  37  is provided in the center of the base  3 . A supporting piece  36  and a terminal block  38  are provided on an end side of the base  3  on the −X side. The supporting piece  36  is used to support the terminal block  88  of the AF actuator  80  from the back side. The AF actuator  80  and the terminal block  88  are connected by the FPC. The terminal block  38  of the base  3  is provided with five terminals  39 . One of the five terminals  39  is a grounding terminal. The remaining four are current input terminals. 
     The FPC  7  is fixed to the upper surface of the base  3 . Lands  71  are provided at six locations on the periphery of the through hole  37  in the FPC  7 . The FPC  7  is a circuit board having wiring from each land  71  to each terminal  39 . 
     The lower crimp plate  4  is formed by arranging a pair of first plate pieces  40 A, a pair of second plate pieces  40 B and a pair of third plate pieces  40 C having arc-shaped curved sides, respectively, so as to form a substantially square shape as a whole with each curved side facing inward. The first plate pieces  40 A, the second plate pieces  40 B, and the third plate pieces  40 C are made of, for example, a conductive material such as SUS. The first plate pieces  40 A, the second plate pieces  40 B, and the third plate pieces  40 C are fixed on the FPC  7  in a state of being separated from each other. 
     Each pair of the first plate pieces  40 A, the second plate pieces  40 B, and the third plate pieces  40 C are arranged at point-symmetrical positions about the center of the through hole  37 . The first plate pieces  40 A and the second plate pieces  40 B are located at positions on both sides across one diagonal line of the lower crimp plate  4  forming an approximately square shape, and the third plate pieces  40 C are located so as to face each other across the other diagonal line of the approximately square shape that is sandwiched between the first plate pieces  40 A and the second plate pieces  40 B. 
     A notch  41  is provided on the curved side of the first plate piece  40 A, and a crimp portion  42 A is provided at a position of the corner portion of the approximately square shape. The crimp portion  42 A is formed by bending a rectangular piece, which protrudes outward in the Y direction with the corner portion as a base end, upward, and then folding the rectangular piece back to the side of the base end. A step is provided between the crimp portion  42 A and the curved side by bending the first plate piece  40 A so as to obtain a same height as that of a crimp portion  52 A of an upper crimp plate  5  to be described later. 
     A notch  41  is provided on the curved side of the second plate piece  40 B, and a crimp portion  42 B is provided at a position of the corner portion of the approximately square shape. The crimp portion  42 B is formed by bending a rectangular piece, which protrudes outward in the X direction with the corner portion as a base end, upward, and then folding the rectangular piece back to the side of the base end. A step is provided between the crimp portion  42 B and the curved side by bending the second plate piece  40 B so as to obtain a same height as that of a crimp portion  52 B of an upper crimp plate  5  to be described later. 
     A notch  41  is provided on the curved side of the third plate piece  40 C, and a notch  43  is provided at a corner portion where the two sides opposite to the curved side intersect. 
     The first plate pieces  40 A, the second plate pieces  40 B, and the third plate pieces  40 C are positioned so that their notches  41  are directly above the lands  71  of the FPC  7 , and are soldered directly to the lands  71  of the FPC  7 . Two first plate pieces  40 A and two second plate pieces  40 B are respectively electrically connected to the current input terminals of five terminals  39  of the terminal block  38  via the wiring of the FPC  7 . Two third plate pieces  40 C are electrically connected to one grounding terminal of five terminals  39  of the terminal block 38  via the wiring of the FPC  7 . 
     The upper crimp plate  5  is made of, for example, a conductive material such as SUS, and has a main body portion  54  in an approximately square shape and two aim portions  55  extending outward in a point-symmetrical manner from two end sides of the main body portion  54  parallel to the Y direction. A through hole  57  is provided in the center of the main body portion  54 . Notches  51  are provided at six locations on the periphery of the through hole  57  in the main body portion  54 . Protruding portions  50  protruding downward are provided at four locations on the periphery of the through hole  57  in the main body portion  54 . As shown in  FIG. 5A , the protruding portion  50  protrudes smoothly from the main body portion  54  and the lower surface portion thereof has a circular flat plate shape. Since the protruding portion  50  can be integrally formed with the upper crimp plate  5  by a press or the like, it is also excellent in impact resistance such as dropping. 
     The corner portions of the upper crimp plate  5  facing each other across one diagonal line are chamfered and rounded and the corner portions facing each other across the other diagonal line are provided with two crimp portions  52 A and  52 B respectively. The crimp portion  52 A is formed by bending a rectangular piece, which protrudes outward in the Y direction with the corner portion as a base end, upward, and then folding the rectangular piece back to the side of the base end. The crimp portion  52 B is formed by bending a rectangular piece, which protrudes outward in the X direction with the corner portion as a base end, upward, and then folding the rectangular piece back to the side of the base end. 
     The aim portion  55  protrudes in the Y direction from the base end at a position close to a corner portion with the crimp portion  52 B on the end side of the main body portion  54  parallel to the Y direction, extends along the end side of the Y direction up to the corner portion on the side without the crimp portion  52 B, turns around the outer side of the corner portion, and extends to the front of the crimp portion  52 A along the end side of the X direction. The tip end of the arm portion  55  is provided with a connection portion  56 . Two of the protruding portions  50  are provided at positions close to the connection portion  56  in the main body portion  54 . 
     The lower crimp plate  4  and the upper crimp plate  5  are placed on the base  3  in this order in such a manner that the approximately square-shaped corner portions thereof overlap the approximately square-shaped corner portions of the base  3 . The crimp portions  42 A and  42 B of the lower crimp plate  4  are arranged at corner portions in the direction of one diagonal line of the approximately square shape, and the crimp portions  52 A and  52 B of the upper crimp plate  5  are arranged at corner portions in the direction of the other diagonal line of the approximately square shape. At this time, the crimp portion  42 A and the crimp portion  52 A are lined up in the X direction, and the crimp portion  42 B and the crimp portion  52 B are lined up in the Y direction. Further, the aim portion  55  is arranged between the chamfered corner portion of the main body portion  54  and the step formed on the first plate piece  40 A and the second plate piece  40 B. Further, the notch  51  of the upper crimp plate  5  is positioned directly above the notch  41  of the lower crimp plate  4 , so that the solder does not come into contact with the upper crimp plate  5 . 
     As shown in  FIG. 5B , two of the four protruding portions  50  of the upper crimp plate  5  abut against the abutted portions of the third plate pieces  40 C of the lower crimp plate  4 . The remaining two of the protruding portions  50  abut against the abutted portions of the second plate pieces  40 B. A low friction layer is formed on the surfaces of the protruding portions  50 , and an insulating layer is formed on the surfaces of the abutted portions of the third plate pieces  40 C and the second plate pieces  40 B against which the protruding portions  50  abut. It is to be noted that, a low friction layer may be formed on the surfaces of the abutted portions of the third plate pieces  40 C and the second plate pieces  40 B, and an insulating layer may be formed on the surfaces of the protruding portions  50 . Further, the lower crimp plate  4  may be provided with protruding portions, and the upper crimp plate  5  may be provided with the abutted portions. 
     It will be described in more detail. When the upper crimp plate  5  is provided with one of the protruding portion  50  and the abutted portion, and the first plate piece  40 A or the second plate piece  40 B of the lower crimp plate  4  is provided with the other of the protruding portion and the abutted portion, as can be seen from the description described later, there is a potential difference between the upper crimp plate  5  and the lower crimp plate  4 . Therefore, at least one of the surface of the protruding portion and the surface of the abutted portion is provided with the insulating layer, and the two are insulated from each other. Then, it is preferable that the frictional coefficient between the two is small, and it is desirable that a low friction layer with a small friction coefficient is provided on the surface thereof, that is, on the surface of the protruding portion or the surface of the abutted portion without the insulating layer, or the surface of the insulating layer. 
     When the upper crimp plate  5  is provided with one of the protruding portion  50  or the abutted portion, and the third plate piece  40 C of the lower crimp plate  4  is provided with the other of the protruding portion or the abutted portion, as can be seen from the description described later, the upper crimp plate  5  and the lower crimp plate  4  have the same potential. Therefore, it is not necessary to provide an insulating layer, and the protruding portion and the abutted portion may abut against each other directly. Further, the layer described in the previous paragraph may be provided, or the insulating layer may not be provided and only the low friction layer may be provided. 
     As shown in  FIG. 5C , the connection portion  56  of the upper crimp plate  5  is joined to the upper surface of the third plate piece  40 C and electrically connected to the third plate piece  40 C. Further, both ends of two SMA wires  6  extending in the X direction are crimped and fixed to the crimp portions  42 A and the crimp portions  52 A, respectively, and both ends of two SMA wires  6  extending in the Y direction are crimped and fixed to the crimp portions  42 B and the crimp portions  52 B, respectively. 
     Five terminals  39  of the terminal block 38  are connected to an external power source. Thereby, a current path of the external power source→the current input terminal→the wiring of the FPC  7 →the first plate pieces  40 A or the second plate pieces  40 B of the lower crimp plate  4 →the SMA wires  6 →the upper crimp plate  5 →the third plate pieces  40 C of the lower crimp plate  4 →the wiring of the FPC  7 →the grounding terminal→the external power source is formed, and a current is supplied to the SMA wires  6 . When a current is supplied to the SMA wires  6 , the SMA wires  6  respectively contract due to heat generated by the electricity supply. Due to the contraction of the SMA wires  6 , the upper crimp plate  5  and the AF actuator  80  supported by the upper crimp plate  5  move in the in-plane direction of XY while sliding on the lower crimp plate  4 . 
     The above is the details of the configuration of the present embodiment. The OIS lens driving device  2 , which is the optical member driving device of the present embodiment, includes the base  3 , the FPC  7  fixed on the base  3 , the lower crimp plate  4  fixed on the FPC  7 , the upper crimp plate  5  sliding on the lower crimp plate  4 , and a plurality of SMA wires  6  fixed to the lower crimp plate  4  and the upper crimp plate  5  at both ends. Further, the lower crimp plate  4  includes the first plate pieces  40 A and the second plate pieces  40 B, which are a plurality of plate pieces having one crimp portion, and each of the plate pieces is fixed on the FPC  7  in a state being separated from each other and is electrically connected to the FPC. Accordingly, as long as individual wiring is provided on the FPC  7  from each of the plate pieces to the terminal  39  connected to the external power source, it is not necessary to provide wiring on each of the plate pieces itself. Therefore, the SMA wire  6  can be directly crimped at the crimp portion without crimping the SMA wire  6  together with the wiring portion. For that reason, according to the present embodiment, it is possible to provide an optical member driving device, a camera device, and an electronic apparatus, in which the SMA wire  6  can be fixed with sufficient strength. 
     Further, in the OIS lens driving device  2  which is the optical member driving device of the present embodiment, the lower crimp plate  4  has a third plate piece  40 C which is a plate piece without crimp portion, and an aim portion  55  extending from the main body portion  54  of the upper crimp plate  5  is electrically connected to the third plate piece  40 C. Accordingly, as long as individual wiring is provided on the FPC  7  from the third plate piece  40 C to the terminal  39  for grounding, it is not necessary to provide wiring to the third plate piece  40 C itself. Therefore, according to the present embodiment, all electrical connections can be realized with the same configuration, and manufacturing is easy. 
     Further, in the OIS lens driving device  2  which is the optical member driving device of the present embodiment, the upper crimp plate  5  which is one of the lower crimp plate  4  and the upper crimp plate  5  has a protruding portion  50  protruding toward the lower crimp plate  4  which is the other of the lower crimp plate  4  and the upper crimp plate  5 , and abuts against the abutted portion provided on the other of the lower crimp plate  4  and the upper crimp plate  5 . Thus, according to the present embodiment, since it is not necessary to fix a plurality of very small parts, the OIS lens driving device  2 , which is the optical member driving device of the present embodiment, is highly reliable and easy to manufacture. Therefore, according to the present embodiment, it is possible to provide an optical member driving device, a camera device, and an electronic apparatus that are highly reliable and easy to manufacture. 
     It is to be noted that in the above embodiment, it is not necessary to make each plate piece forming the lower crimp plate  4  by individual press working. All of the plate pieces forming the lower crimp plate  4  may be integrated by press working, fixed to the FPC  7 , and then the connecting portion of each plate piece may be cut. 
     It is to be noted that a metal layer suitable for sliding may be provided on the surface of the insulating layer provided on the surface of the protruding portion or the surface of the abutted portion. Further, instead of providing the insulating layer and the low friction layer separately, a layer that serves as both the insulating layer and the low friction layer may be provided. Further, in  FIG. 4  and  FIG. 5 , the abutted portion is not marked and has the same height as those of the surroundings thereof, but it may be provided higher or lower than the surroundings thereof.