JP2010286820A - LENS DRIVE DEVICE AND METHOD OF ASSEMBLING THE SAME - Google Patents

Abstract

An object of the present invention is to prevent the shape of a housing from becoming complicated for electrode attachment.
A lens driving device includes a lens holder including a cylindrical portion that holds a lens barrel, a housing that supports the lens holder so as to be movable only in the optical axis O direction, and the lens holder. A moving means for moving in the optical axis O direction and a guiding means for guiding the lens holder 18 so as to be movable only in the optical axis O direction are provided. The moving means includes a shape memory alloy member 32 stretched between the lens holder 18 and the housing 12. A pair of electrodes 34 are attached to both ends of the shape memory alloy member 32 to energize it. The housing 12 includes an actuator base 14 disposed on the lower side of the lens holder 18, and an electrode holder 22 attached to the actuator base 14 and holding a pair of electrodes 34.
[Selection] Figure 4

Description

  The present invention relates to a lens driving device, and more particularly to a lens driving device using a shape memory alloy for an actuator and an assembling method thereof.

  As a camera autofocus actuator and zoom actuator, a linear actuator using a shape memory alloy (SMA) (drive device) is known.

  For example, WO2007 / 113478A1 (Patent Document 1) discloses a camera lens driving device that drives the movement of one camera lens supported by one support structure (housing) by one suspension system. The camera lens driving device disclosed in Patent Document 1 mounts a subassembly having an SMA wire connected to at least one mounting member mounted on a support structure. At least two SMA wires are held with tension between the camera lens element and the support structure (housing), each at an acute angle with respect to the optical axis to which tension is applied having a component along the optical axis. The two SMA wires are held at an angle when viewed along the optical axis. The subassembly has a mounting member that connects the SMA wires by caulking. The mounting member is electrically connected to the SMA wire. Thus, the attachment member acts as an electrode. The attachment member (electrode) is attached to a recess formed in the support structure (annular wall).

  Japanese Patent Laying-Open No. 2007-292864 (Patent Document 2) discloses a lens driving device that improves transmission efficiency and is compact. The lens driving device disclosed in Patent Document 2 includes a fixed barrel (housing), a lens frame (lens holder) that holds a part or all of a lens group (lens barrel) constituting an optical system, and a fixed mirror. Guide means for supporting the lens frame (lens holder) movably in the optical axis direction with respect to the tube, and biasing means for biasing the lens frame toward one side in the optical axis direction. The lens driving device moves the lens frame toward the other side against the bias of the biasing means with respect to the fixed barrel.

  The lens driving device disclosed in Patent Document 2 includes a shape memory alloy (SMA) wire and a wire bearing member. Both ends of the SMA wire are fixed to the fixed lens barrel, and when heated by energization, the SMA wire is contracted from a predetermined length of a relaxed state. The shape memory alloy wire returns to its relaxed length when it is cooled by stopping energization. The wire bearing member is provided on the lens frame, and an action portion set between both ends of the shape memory alloy wire is hooked so that the convex direction is in a curved direction facing the one side.

  In the embodiment of the lens driving device disclosed in Patent Document 2, both ends of the SMA wire are fixed to a pair of wire support members, and the pair of wire support members are fixed to a fixed barrel (housing). The energization control unit energizes both ends of the SMA wire via the pair of wire support members. Therefore, the wire support member acts as an electrode.

  Furthermore, Japanese Patent Application Laid-Open No. 2007-78954 (Patent Document 3) discloses a lens barrel configured to move an imaging lens in the optical axis direction using a shape memory alloy. The lens barrel disclosed in Patent Document 3 has an imaging lens (lens barrel) that forms an image of subject light, and a lens frame (lens holder) that holds the imaging lens (lens barrel), and has a string shape. The imaging lens is moved in a predetermined direction using the formed shape memory alloy. A part of the shape memory alloy is disposed in the optical path of the imaging lens (lens barrel), and the shape memory alloy is contracted by energization to move the lens frame (lens holder). Patent Document 3 also discloses an embodiment of a lens barrel in which a pair of leaf springs of diaphragm time are provided at both ends in the optical axis direction of a lens frame (lens holder).

  In the embodiment of the lens barrel disclosed in Patent Document 3, both end portions of the shape memory alloy formed in a string shape are sandwiched and fixed by a pair of plate members to a columnar portion (housing) erected from the ground plate. ing. The shape memory alloy is energized through the plate member. Therefore, the plate member functions as an electrode.

  Japanese Patent Laying-Open No. 2009-19507 (Patent Document 4) discloses a drive module and an assembling method thereof that can reduce variations in assembling accuracy while improving manufacturing efficiency. The drive module disclosed in Patent Document 3 is a shape memory alloy (SMA) wire in which a driven body (lens holder) movably provided on a chassis (housing; support body) expands and contracts in accordance with the amount of energization. It is locked to the middle part. The drive module includes a pair of holding terminals, and the chassis (housing; support) includes a positioning portion and a locking portion. Each holding terminal has a wire holding portion that holds the end portion of the SMA wire so as to be conductive, a positioned portion with respect to the support, and a locked portion that receives a reaction force from the support toward the positioned portion. . A positioning part latches the to-be-positioned part of a holding terminal. The locking portion locks the locked portion of the holding terminal in the pressed state toward the positioned portion side. Since the holding terminal is an energizing portion, it functions as an electrode.

WO2007 / 113478A1 JP 2007-292864 A JP 2007-78954 A JP 2009-19507 A

  Patent Documents 1 to 4 described above have problems as described below.

  In the camera lens driving device disclosed in Patent Document 1, an attachment member (electrode) for a shape memory alloy wire is directly attached to one support structure. As a result, the shape of the support structure is complicated due to electrode attachment. Further, it is difficult to disassemble the product when the characteristic is poor, and it is difficult to reuse the parts.

  Also in the lens driving device disclosed in Patent Document 2, a pair of wire support members (electrodes) for SMA wires are directly fixed to a fixed barrel (housing). As a result, the shape of the fixed lens barrel (housing) becomes complicated due to electrode attachment. Further, it is difficult to disassemble the product when the characteristic is poor, and it is difficult to reuse the parts.

  Also in the lens barrel disclosed in Patent Document 3, a pair of plate members (electrodes) are directly fixed to a columnar portion (housing). As a result, the shape of the housing becomes complicated due to electrode mounting. Further, it is difficult to disassemble the product when the characteristic is poor, and it is difficult to reuse the parts.

  Also in the drive module disclosed in Patent Document 4, a pair of holding terminals (electrodes) for SMA wires are directly attached to the chassis (housing). As a result, the shape of the chassis (housing) becomes complicated due to electrode attachment. Further, it is difficult to disassemble the product when the characteristic is poor, and it is difficult to reuse the parts.

  Moreover, all of patent documents 1-4 use the shape memory alloy wire formed in the shape of a line as a shape memory alloy member. As a result, there is a limit to the amount of lens displacement of the lens driving device. In other words, the lens displacement amount of the lens driving device depends on the displacement amount of the shape memory alloy wire.

  Accordingly, an object of the present invention is to provide a lens driving device and an assembling method thereof that can simplify the shape of a support (actuator base) that supports a shape memory alloy member.

  An object of the present invention is to provide a lens driving device and an assembling method thereof that can easily disassemble a product at the time of characteristic failure and can reuse components.

  Another object of the present invention is to provide a lens driving device capable of greatly increasing the amount of lens displacement.

  Other objects of the invention will become apparent as the description proceeds.

  According to the first aspect of the present invention, the lens holder (18) including the cylindrical portion (182) that holds the lens barrel (11), and the lens holder (18) are moved only in the optical axis (O) direction. A housing (12) that can be supported, a moving means for moving the lens holder (18) in the optical axis (O) direction, and a guiding means for guiding the lens holder (18) so as to be movable only in the optical axis (O) direction. In the lens driving device (10; 10A; 10B), the moving means is a shape memory alloy member (32; 32A; 32B-) stretched between the lens holder (18) and the housing (12). 1, 32B-2), and a pair of electrodes (34; 34B-1, 34B-2) for supplying current to both ends of the shape memory alloy member (32; 32A; 32B-1, 32B-2). ) Is attached The housing (12) includes an actuator base (14) disposed on the lower side of the lens holder (18) and a pair of electrodes (34; 34B-1, 34B) attached to the actuator base (14). A lens driving device including an electrode holder (22) for holding 2).

  In the lens driving device (10; 10A; 10B) according to the first aspect of the present invention, the lens holder (18) protrudes radially outward from the cylindrical portion (182) to form the shape memory alloy member (32; 32A). 32B-1, 32B-2) preferably have latching protrusions (184; 184B-1, 184B-2) for latching intermediate portions (32a; 32Aa; 32B-1a, 32B-2a). The guide means may include, for example, an elastic member (26, 28) disposed between the lens holder (18) and the housing (12). In this case, the elastic members (26, 28) support the lens holder (18) so as to be displaceable only in the optical axis (O) direction with the lens holder (18) positioned in the radial direction. The elastic member includes an upper leaf spring (26) and a lower leaf spring (28) provided on the upper side and the lower side, respectively, in the optical axis (O) direction of the cylindrical portion (182) of the lens holder (18). It is desirable. The upper leaf spring (26) includes, for example, an upper ring portion (262) attached to the upper end portion of the lens holder (18), four upper end portions (264) attached to the housing (12), and an upper ring portion. You may comprise from four upper arm parts (266) which each connect four upper edge parts. The lower leaf spring may be composed of a pair of lower leaf springs (28). In that case, each of the pair of lower leaf springs (28) includes, for example, a lower arc portion (282) attached to the lower end portion of the lens holder (18) and a pair of lower end portions fixed to the housing (12). A portion (284) and a pair of lower arm portions (286) connecting the lower arc portion and the pair of lower end portions may be included. The shape memory alloy member may be composed of a shape memory alloy wire (32) formed in a linear shape. Instead, the shape memory alloy member may be composed of a shape memory alloy member (32A; 32B-1, 32B-2) formed in a coil shape. A plurality of latching protrusions (184; 184B-1; 184B-2) are arranged on the outer peripheral wall of the cylindrical portion (182) at equal angular intervals with the optical axis (O) as the center, and the shape memory alloy member (32B-1) , 32B-2) are arranged in the same number as the number of the hooking protrusions (184; 184B-1; 184B-2) and are hooked on the hooking protrusions (184; 184B-1; 184B-2), respectively. Good.

  According to the second aspect of the present invention, the upper leaf spring (26) is provided at both ends in the optical axis (O) direction of the lens holder (18) having the cylindrical portion (182) for holding the lens barrel (11). And the lower plate spring (28) and the support member (22, 24) in which the shape memory alloy assembly (36; 36A; 36B-1, 36B-2) is attached to the lens holder (18). 24B) and the actuator base (14) on the support member (22, 24; 24B) with the lower leaf spring (28) sandwiched from the bottom side of the lens holder (18). A third step of attaching, and a fourth step of attaching the inner upper cover (30) to the support member (22, 24; 24B) with the upper leaf spring (26) sandwiched from the upper side of the lens holder (18). Process and inner upper cover (30) so as to cover the lens driving device including a fifth step of covering the outer upper cover (16), a method of assembling (10;; 10A 10B) is obtained.

  In the method of assembling the lens driving device (10; 10A; 10B) according to the second aspect of the present invention, the shape memory alloy assembly (36; 36A; 36B-1, 36B-2) is a shape memory alloy member (32; 32A; 32B-1, 32B-2) and a pair of electrodes (34; 34B-1, 34B-2) electrically connected to both ends of the shape memory alloy member, and a lens holder (18) Has first and second sides facing each other, and has a latching projection (184; 184B-1, 184B-2) projecting outward from the outer wall of the tubular portion (182) on the first side. The support member includes first and second support members (22, 24; 24B) installed to face each other. The first support member (22) includes a pair of electrodes (34; 34B-1). , 34B-2) with shape memory Kim assembly (36; 36A; 36B-1,36B-2) may attached. In this case, in the second step, the intermediate portion (32a; 32Aa; 32B-1a, 32B-2a) of the shape memory alloy member (32; 32A; 32B-1, 32B-2) is engaged with the latching protrusion (184; 184B-1; 184B-2), the shape memory alloy member (32; 32A; 32B-1, 32B-2) is placed between the lens holder (18) and the first support member (22). And attaching the first support member (22) to the first side of the lens holder (18) and attaching the second support member (24; 24B) to the second side of the lens holder (18). Attaching to the side.

  The upper leaf spring (26) includes an upper ring portion (262), four upper end portions (264) provided at four corners and having upper spring holes (264a), an upper ring portion, and four upper end portions. The lower leaf spring is composed of a pair of lower leaf springs (28), and each of the pair of lower leaf springs is connected to the lower arc portion (282). And a pair of lower ends (284) having a lower end hole (284a), and a pair of lower arms (286) connecting the lower arc portion and the pair of lower ends. Good. In this case, the first step includes a step of attaching the upper ring portion (262) of the upper leaf spring (26) to the upper end portion of the cylindrical portion (182) of the lens holder (18), and a pair of lower leaf springs ( 28) attaching the lower circular arc part (282) to the lower end part of the cylindrical part (182) of the lens holder (18).

  Each of the first and second support members (22, 24; 24B) includes a pair of support protrusions (224, 244; 244B) on both ends thereof, and each of the pair of support protrusions has a support protrusion on the upper end. (224a, 244a). In this case, in the second step, the support protrusions (224a, 244a) of the first and second support members (22, 24; 24B) are respectively connected to the four upper end portions ( H.264) is inserted into the upper end hole (264a).

  The actuator base (14) includes a ring-shaped base portion (14) and four base protrusions (142) protruding upward at the four corners of the base portion. You may have four base protrusions (142a) which protrude upwards. In this case, in the third step, the four base protrusions (142a) formed on the four base protrusions (142) of the actuator base (14) are respectively connected to the pair of lower leaf springs (28). The four base protrusions (142) of the actuator base (14) are passed through the lower end hole (284a) formed in the lower end portion (284) of the actuator base (14), respectively. The support members (22, 24; 24B) are attached to a pair of protrusions (224, 244; 244B).

  The inner upper cover (30) includes a ring-shaped inner cover body (302) and four locking protrusions (304) protruding downward at the four corners of the inner cover body. Each of the parts may have a through hole (304a). In this case, in the fourth step, the first and second support members (22, 24; 24B) projecting through the upper end holes (264a) of the four upper ends (264) of the upper leaf spring (26). ) Support protrusions (224a, 244a) are inserted into through holes (304a) formed in the four locking protrusions (304) of the inner upper cover (30), respectively, and the first and second The inner upper cover (30) is attached to the support member (22, 24; 24B).

  The reference numerals in the parentheses are given for ease of understanding, and are merely examples, and of course are not limited thereto.

  In the present invention, the housing includes an actuator base disposed on the lower side of the lens holder, and an electrode holder that is attached to the actuator base and holds a pair of electrodes, thereby supporting the shape memory alloy member. The shape of the support (actuator base) can be simplified. Further, the product can be easily disassembled when the characteristic is defective, and the parts can be reused.

It is the perspective view which looked at the external appearance of the lens drive device by the 1st Embodiment of this invention from diagonally forward upper direction. FIG. 2 is a perspective view of the lens driving device shown in FIG. FIG. 3 is a perspective view of the lens driving device shown in FIG. 2 as viewed from diagonally forward and with the outer upper cover omitted. It is the disassembled perspective view which looked at the lens drive device shown in FIG. 2 from diagonally forward upper direction. FIG. 4 is a front view of the lens driving device shown in FIG. 3. It is the perspective view which looked at the state which attached the SMA assembly shown in FIG. 5 to the electrode holder from diagonally forward upper direction. It is the perspective view which looked at the state shown in FIG. 6 from diagonally backward upper direction. It is the perspective view which looked at the state which attached the elastic member to the lens holder from diagonally forward upper direction. It is the perspective view which looked at the state shown in FIG. 8 from diagonally forward lower. It is a perspective view which shows the flow of the 1st assembly process of the lens drive device shown in FIG. 2 seeing from diagonally forward upper direction. It is a perspective view which shows the flow of the 2nd assembly process of the lens drive device shown in FIG. 2 seeing from diagonally forward upper direction. It is a perspective view which shows the flow of the 3rd assembly process of the lens drive device shown in FIG. 2 seeing from diagonally forward upper direction. It is a perspective view which shows the flow of the 4th assembly process of the lens drive device shown in FIG. 2 seeing from diagonally forward upper direction. It is the perspective view seen from diagonally forward upper direction, omitting the lens barrel and the outer upper cover from the lens driving device according to the second embodiment of the present invention. It is a front view of the lens drive device shown in FIG. It is the perspective view which looked at the state which attached the SMA assembly shown in FIG. 11 to the electrode holder from diagonally backward upper direction. It is a perspective view which shows the lens holder and SMA assembly which are used with the lens drive device by the 3rd Embodiment of this invention. It is the disassembled perspective view which looked at the lens drive device by the 3rd Embodiment of this invention from diagonally forward upper direction. It is the perspective view seen from the diagonally forward upper side, omitting the outer upper cover from the lens driving device according to the fourth embodiment of the present invention. FIG. 17 is a perspective view of the lens driving device shown in FIG. 16 as viewed obliquely from the upper front, omitting the actuator base, the elastic member, and the electrode holder. It is the disassembled perspective view which looked at the lens drive device by the 4th Embodiment of this invention from diagonally forward upper direction. It is a front view of the lens drive device shown in FIG. FIG. 18 is a top view of the lens driving device shown in FIG. 17. It is the perspective view seen from diagonally forward upper direction, omitting the outer upper cover from the lens driving device according to the fifth embodiment of the present invention. FIG. 17 is a perspective view of the lens driving device shown in FIG. 16 as viewed obliquely from the upper front, omitting the actuator base, the elastic member, and the electrode holder. It is the disassembled perspective view which looked at the lens drive device by the 5th Embodiment of this invention from diagonally forward upper direction. It is a front view of the lens drive device shown in FIG. It is a side view of the lens drive device shown in FIG. It is a top view of the lens drive device shown in FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  A lens driving device 10 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 is a perspective view of the external appearance of the lens driving device 10 as viewed obliquely from above and front. FIG. 2 is a perspective view of the lens driving device 10 as viewed obliquely from above and in a state where the lens barrel 11 is omitted. FIG. 3 is a perspective view of the lens driving device 10 as viewed obliquely from above and in a state where the lens barrel 11 and the outer upper cover 16 are omitted. FIG. 4 is an exploded perspective view of the lens driving device 10 viewed obliquely from above and in a state where the lens barrel 11 is omitted. FIG. 5 is a front view showing the lens driving device 10 with the lens barrel 11, the outer upper cover 16 and the inner upper cover (stopper) 30 omitted.

  Here, as shown in FIGS. 1 to 5, an orthogonal coordinate system (X, Y, Z) is used. 1 to 5, in the orthogonal coordinate system (X, Y, Z), the X-axis direction is the front-rear direction (depth direction), the Y-axis direction is the left-right direction (width direction), and Z The axial direction is the vertical direction (height direction). In the example shown in FIGS. 1 to 5, the vertical direction Z is the direction of the optical axis O of the lens. In the present specification, the forward direction is also referred to as the first side, and the backward direction is also referred to as the second side.

  However, in the actual use situation, the optical axis O direction, 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 backward direction.

  The illustrated lens driving device 10 has a plane-symmetric structure with respect to a plane that passes through the optical axis O and is defined (extends) by the front-rear direction X and the vertical direction Z.

  The illustrated lens driving device 10 is provided in a camera-equipped mobile phone capable of autofocusing, for example. The lens driving device 10 includes a lens barrel (lens assembly) 11 that incorporates an autofocus lens AFL that is a movable lens. The lens driving device 10 is for moving the lens barrel 11 only in the optical axis O direction.

  As shown in FIG. 1, the lens driving device 10 includes a substantially rectangular parallelepiped housing (housing) 12 that covers a lens barrel 11. In other words, the lens barrel 11 is arranged in the housing (housing) 12. The housing (housing) 12 includes an actuator base 14 and an outer upper cover 16.

  On the other hand, although not shown, an image sensor arranged on the substrate is mounted at the center of the actuator base 14. This imaging device captures a subject image formed by the movable lens AFL and converts it into an electrical signal. The imaging device is configured by, for example, a CCD (charge coupled device) type image sensor, a CMOS (complementary metal oxide semiconductor) type image sensor, or the like.

  The lens driving device 10 includes a lens holder 18 that holds the lens barrel 11. In other words, the lens barrel 11 is held and fixed in the lens holder 18. More specifically, the lens holder 18 includes a cylindrical portion 182 having a substantially cylindrical shape. A female screw (not shown) is cut on the inner peripheral wall of the cylindrical portion 182 of the lens holder 18. On the other hand, a male screw (shown) that is screwed into the female screw is cut on the outer peripheral wall of the lens barrel 11. Therefore, in order to attach the lens barrel 11 to the lens holder 18, the lens barrel 11 is rotated around the optical axis O with respect to the lens holder 18 and screwed along the optical axis O direction. It is accommodated in the lens holder 18 and joined together by an adhesive or the like.

  The lens holder 18 is supported in the housing 12 so as to be movable only in the direction of the optical axis O, as will be described later. The lens movable portion (11, 18) is configured by a combination of the lens barrel 11 and the lens holder 18.

  An outer peripheral wall of the cylindrical portion 182 of the lens holder 18 has a protruding portion 184 that protrudes radially outward in front of the front-rear direction X. The protruding portion 184 protrudes along the vertical direction Z from the upper end to the lower end of the cylindrical portion 182. The protruding portion 184 is for hooking an intermediate portion 32a of a shape memory alloy wire 32 formed in a linear shape to be described later. Therefore, the protrusion 184 is also called a latching protrusion.

  The actuator base 14 has a ring-shaped base portion 142 and four base protruding portions 144 that slightly protrude upward in the vertical direction Z at the four corners of the base portion 142. Each of the four base protrusions 144 has four base protrusions 144a protruding upward. Of the four base protrusions 144, a front recess 146 is formed between the two front base protrusions 144, and a rear recess 148 is formed between the two rear base protrusions 144.

  The housing (housing) 12 further includes a front support member 22 and a rear support member 24. The front support member 22 is attached to the front of the actuator base 14, and the rear support member 24 is attached to the rear of the actuator base 14. The front support member 22 and the rear support member 24 have substantially the same shape. The front support member 22 and the rear support member 24 are disposed in plane symmetry with respect to a plane that passes through the optical axis O and that is defined by (extends in) the left-right direction Y and the up-down direction Z. In other words, the front support member 22 and the rear support member 24 are in a mirror image relationship with respect to the plane.

  The front support member 22 is also called a first support member, and the rear support member 24 is also called a second support member. The first and second support members are collectively referred to simply as a support member.

  The front support member 22 is also referred to as an electrode holder because it is for holding a pair of electrodes 34 to be described later.

  The front support member (electrode holder) 22 has a pair of front supports mounted on a front base portion 222 inserted into the front recess 146 of the actuator base 14 and a pair of base protrusions 144 in front of the actuator base 14. The projecting portion 224 includes a pair of front support connecting portions 226 that connect between both ends of the front base portion 222 and the pair of front support projecting portions 224. The pair of front support protrusions 224 protrude upward, and have a pair of front support protrusions 224a that protrude upward. Although not shown, the pair of front support protrusions 224 has a pair of front support holes into which a pair of base protrusions 144a protruding from the front pair of base protrusions 144 are inserted. As will be described later, the pair of electrodes 34 is held by a pair of front support connecting portions 226.

  Similarly, the rear support member 24 includes a rear base portion 242 inserted into the rear recess 148 of the actuator base 14 and a pair of rear support projections mounted on the pair of base protrusions 144 behind the actuator base 14. Part 244, and a pair of rear support connection parts 246 for connecting between both ends of the rear base part 242 and the pair of rear support protrusions 244. The pair of rear support protrusions 244 protrude upward and each have a pair of rear support protrusions 244a protruding upward. Although not shown, the pair of rear support protrusions 244 have a pair of rear support holes into which the pair of base protrusions 144a protruding from the pair of rear base protrusions 144 are inserted.

  The lens driving device 10 includes an upper leaf spring 26 and a pair of lower leaf springs 28 provided on the upper and lower sides of the cylindrical portion 182 of the lens holder 18 in the optical axis O direction. The upper leaf spring 26 and the pair of lower leaf springs 28 are disposed between the lens holder 18 and the housing 12 and elastically support the lens holder 18 so as to be displaceable in the optical axis O direction with the lens holder 18 positioned in the radial direction. Acts as member 20.

  Further, as described above, in an actual use situation, the upward direction in the Z-axis direction (optical axis O direction) is the forward direction, and the downward direction in the Z-axis direction (optical axis O direction) is the backward direction. Therefore, the upper leaf spring 26 is also called a front spring, and the pair of lower leaf springs 28 is also called a rear spring.

  The upper leaf spring 26 is disposed above the lens holder 18 in the optical axis O direction, and the pair of lower leaf springs 28 are disposed below the lens holder 18 in the optical axis O direction.

  The upper leaf spring 26 has an upper ring portion 262 attached to the lens holder 18 and four upper end portions 264 attached to the four corners of the housing 12 as will be described later. Four upper arm portions 266 are provided between the upper ring portion 262 and the four upper end portions 264. That is, the four upper arm portions 266 connect the upper ring portion 262 and the four upper end portions 264.

  The upper ring portion 262 of the upper leaf spring 26 is fixed to the cylindrical portion 182 of the lens holder 18. More specifically, the lens holder 18 has four upper holder protrusions 186 that protrude radially outward from the upper end of the cylindrical portion 182. Each of the four upper holder protrusions 186 has four upper holder protrusions 186a that protrude upward. The upper ring portion 262 of the upper leaf spring 26 has four upper spring holes 262a into which the four upper holder projections 186a are respectively inserted.

  On the other hand, the four upper end portions 264 of the upper leaf spring 26 are fixed to the pair of front support protrusions 224 of the front support member 22 and the pair of rear support protrusions 244 of the rear support member 24. More specifically, the four upper end portions 264 of the upper leaf spring 26 are respectively paired with a pair of front support protrusions 224 a and a pair of rear support protrusions 244 formed on the pair of front support protrusions 224. It has four upper end holes 264a into which the rear support protrusions 244a are inserted. The housing 12 further includes a resin inner upper cover 30 provided inside the outer upper cover 16. The four upper end portions 264 of the upper leaf spring 26 are fixed by the inner upper cover 30.

  More specifically, the inner upper cover 30 includes an inner cover body 302 having a ring shape, four locking protrusions 304 slightly protruding downward at the four corners of the inner cover body 302, and a pair of front protrusions 304. A pair of front extending portions 306 extending downward in the vicinity, and a pair of rear extending portions 308 extending downward in the vicinity of the rear pair of projecting portions 304. Each of the four locking projections 304 has four through holes 304a into which the pair of front protrusions 224a of the front support member 22 and the pair of rear support protrusions 244a of the rear support member 24 are inserted. Accordingly, the four upper end portions 264 of the upper leaf spring 26 include the four locking protrusions 304 of the inner upper cover 30, the pair of front support protrusions 224 of the front support member 22, and the pair of rear ends of the rear support member 24. It is fixed in a state of being sandwiched between the support protrusions 244. The inner upper cover 30 has a function of preventing the upper leaf spring 26 from being detached from the front support member 22 and the rear support member 24 and is therefore also called a stopper.

  Accordingly, the housing 12 includes the actuator base 14, the outer upper cover 16, the front support member (electrode holder) 22, the rear support member 24, and the inner upper cover (stopper) 30.

  One of the pair of lower leaf springs 28 is provided on the right side in the left-right direction Y, and the other is provided on the left side in the left-right direction Y. The pair of lower leaf springs 28 are arranged in plane symmetry with respect to a plane that passes through the optical axis O and is defined by (extends in) the front-rear direction X and the vertical direction Z. In other words, one and the other of the pair of lower leaf springs 28 are mirror images of each other with respect to the plane.

  The right lower leaf spring 28 has a lower arc portion 282 extending in an arc shape in the front-rear direction X on the right side, and a pair of lower end portions 284 provided at two corners in the front-rear direction X on the right side. A pair of lower arm portions 286 is provided between the lower arc portion 282 and the pair of lower end portions 284. In other words, the pair of lower arm portions 286 connects the lower arc portion 282 and the pair of lower end portions 284. The pair of lower end portions 284 has a pair of lower end hole 284a into which a pair of base projections 144a provided on the right side among the four base projections 144a of the actuator base 14 are fitted. Accordingly, the pair of lower end portions 284 of the right lower leaf spring 28 are formed by the pair of base protrusions 144 on the right side of the actuator base 14, the front protrusions 224 on the right side of the front support member 22, and the rear support member 24. It is clamped between the right rear protrusion 244 and fixed. The lower arc portion 282 of the right lower leaf spring 28 is attached to the right side of the lower end portion of the cylindrical portion 182 of the lens holder 18.

  Similarly, the left lower leaf spring 28 includes a lower arc portion 282 extending in an arc shape in the front-rear direction X on the left side, and a pair of lower end portions 284 provided at two corners in the left front-rear direction X. Have A pair of lower arm portions 286 is provided between the lower arc portion 282 and the pair of lower end portions 284. In other words, the pair of lower arm portions 286 connects the lower arc portion 282 and the pair of lower end portions 284. The pair of lower end portions 284 has a pair of lower end hole 284a into which a pair of base projections 144a provided on the left side among the four base projections 144a of the actuator base 14 are fitted. Accordingly, the pair of lower end portions 284 of the left lower leaf spring 28 is formed by the pair of base protrusions 144 on the left side of the actuator base 14, the front protrusions 224 on the left side of the front support member 22, and the rear support member 24. It is clamped between the left rear protrusion 244 and fixed. The lower arc portion 282 of the left lower leaf spring 28 is attached to the left side of the lower end portion of the cylindrical portion 182 of the lens holder 18.

  The elastic member 20 including the upper leaf spring 26 and the pair of lower leaf springs 28 serves as a guide means for guiding the lens holder 18 so as to be movable only in the direction of the optical axis O. Each of the upper leaf spring 26 and the pair of lower leaf springs 28 is made of metal such as beryllium copper, phosphor bronze, and stainless steel. The upper leaf spring 26 and the lower leaf spring 28 are manufactured by pressing a predetermined thin plate or etching using a photolithography technique. In addition, the etching process is more preferable than the press process. This is because no residual stress remains in the etching process.

  With such a configuration, the lens movable portions (11, 18) can move only in the direction of the optical axis O with respect to the housing (housing) 12.

  The lens driving device 10 is electrically connected to a shape memory alloy wire 32 formed in a linear shape in the vicinity of the outer wall of the cylindrical portion 182 of the lens holder 18 and both ends of the shape memory alloy wire 32. And a pair of electrodes 34. The combination of a shape memory alloy (SMA) wire 32 and a pair of electrodes 34 is referred to as a shape memory alloy (SMA) assembly 36. The SMA assembly 36 is held by the front support member (electrode holder) 22 as described later.

  With reference to FIG.6 and FIG.7, the attachment state to the front support member (electrode holder) 22 of the SMA assembly 36 is demonstrated. FIG. 6 is a perspective view of the state in which the SMA assembly 36 is attached to the electrode holder 22 as viewed obliquely from above and front. FIG. 7 is a perspective view of the state in which the SMA assembly 36 is attached to the electrode holder 22 as viewed obliquely from above and rearward.

  The pair of electrodes 34 has a symmetrical shape. The pair of electrodes 34 extends substantially in the vertical direction Z. Each electrode 34 includes a substantially L-shaped held portion 342 held by the front support connecting portion 226, a connection portion 344 bent in a U-shaped cross section at the upper end portion of the held portion 342, and the held portion. 342 and a strip-shaped terminal portion 346 extending downward from the inner end portion of 342. Each electrode 34 is electrically connected to the end of the shape memory alloy wire 32 by caulking the connection portion 3444. The terminal portion 346 is for receiving a drive current from a drive circuit (not shown).

  As shown in FIG. 6, the held portion 342 of the electrode 34 is held on the back surface of the front support connecting portion 226 of the electrode holder 22. The held portion 342 has a circular hole 342a.

  As shown in FIG. 7, the front support connecting portion 226 has a columnar first protrusion 226 a that protrudes rearward from the back surface thereof so as to be fitted into the circular hole 342 a of the held portion 342. Further, the front support connecting portion 226 has a second protruding portion 226 b that protrudes rearward from the back surface so as to be engaged with the bottom surface portion of the held portion 342. Further, the front support connecting portion 226 has a substantially triangular prism-shaped third protrusion 226 c that protrudes rearward from the back surface thereof so as to engage with the L-shaped inner bent portion of the held portion 342. The outer side surface of the held portion 342 of the electrode 34 is locked to the inner side wall of the front support protrusion 224 of the electrode holder 22.

  In this way, the SMA assembly 36 is attached to the front support member (electrode holder) 22. The intermediate portion 32 a of the shape memory alloy wire 32 is hooked with the protruding portion (holding protrusion) 184 of the lens holder 18. That is, the shape memory alloy wire 32 is stretched between the lens holder 18 and the housing 12.

  Next, a schematic operation of the lens driving device 10 will be described.

  As is well known, a “shape memory alloy” is a metal having a property that a given deformation strain becomes zero in a specific temperature region and recovers to its original shape. The shape memory alloy is made of, for example, a TiNi alloy.

  The illustrated shape memory alloy wire 32 contracts to a pre-stored contraction length when self-heating is caused by energization, and to an original length (length in a relaxed state) predetermined by natural cooling when the energization is stopped. It is a return type wire.

  The elastic member 20 acts to urge the lens holder 18 downward along the optical axis O direction. On the other hand, the shape memory alloy wire 32 contracts when energized through a pair of electrodes 34 from a drive circuit (not shown). As a result, the lens holder 18 moves upward along the optical axis O direction against the downward biasing force of the elastic member 20.

  On the other hand, when the energization to the shape memory alloy wire 34 is stopped, the shape memory alloy wire 32 is naturally cooled. As a result, the shape memory alloy wire 32 expands due to the downward biasing force of the elastic member 20. As a result, the lens holder 18 moves downward along the optical axis O direction.

  That is, the shape memory alloy wire 32 expands and contracts in the direction of the optical axis O due to a temperature change caused by energization / non-energization, and functions as a moving unit that moves the lens holder 18 in the direction of the optical axis O.

  The combination of the elastic member 20 and the SMA assembly 36 is a lens driving unit (20, 20) that drives the lens moving unit (11, 18) while supporting the lens moving unit (11, 18) so as to be movable in the optical axis O direction. 36).

  The lens driving unit (20, 36) and the lens movable unit (11, 18) are juxtaposed with respect to the optical axis O as shown in FIG. Therefore, the lens driving device 10 can be reduced in height.

  Next, an assembling method of the lens driving device 10 will be described with reference to FIGS. 8 to 10D. FIG. 8 is a perspective view of the state in which the elastic member 20 is attached to the lens holder 18 as viewed obliquely from above and front. FIG. 9 is a perspective view of a state in which the elastic member 20 is attached to the lens holder 18 as viewed obliquely from below and forward. 10A to 10D are perspective views showing the flow of the first to fourth assembly steps of the lens driving device 10 as viewed obliquely from the upper front.

  As shown in FIGS. 8 and 9, first, the elastic member 20 is attached to the lens holder 18.

  In this state, as shown in FIG. 8, the upper ring portion 262 of the upper leaf spring 26 is fixed to the upper end portion of the cylindrical portion 182 of the lens holder 18. At this time, the four upper holder protrusions 186 a formed on the four upper holder protrusions 186 protruding at the upper end of the cylindrical part 182 are inserted into the four upper spring holes 262 a formed on the upper ring part 262. Yes.

  Further, as shown in FIG. 9, the lower arc portion 282 of the pair of lower leaf springs 28 is attached to the lower end portion of the cylindrical portion 182 of the lens holder 18.

  Subsequently, as shown in FIG. 10A, the front support member (electrode holder) 22, the SMA assembly 36, and the rear support member 24 are attached to the lens holder 18 to which the elastic member 20 is attached.

  More specifically, first, an assembly formed by attaching the SMA assembly 36 to the front support member (electrode holder) 22 as shown in FIGS. 6 and 7 is attached to the lens holder 18. At this time, the pair of front support protrusions 224 a formed on the pair of front support protrusions 224 of the front support member (electrode holder) 22 is paired with the pair of upper end portions 264 in front of the upper leaf spring 26. The upper end hole 264a is inserted. The intermediate portion 32 a (see FIGS. 6 and 7) of the shape memory alloy wire 32 is hooked on the protruding portion (holding protrusion) 184 of the lens holder 18. Further, the pair of rear support protrusions 244 a formed on the pair of rear support protrusions 244 of the rear support member 24 are paired with a pair of upper end holes 264 a formed on the pair of upper end portions 264 behind the upper leaf spring 26. Inserted.

  Next, as shown in FIG. 10B, the actuator base 14 is attached to the front support member (electrode holder) 22 and the rear support member 24. At this time, the pair of base protrusions 144 a (see FIG. 4) formed on the pair of base protrusions 144 in front of the actuator base 14 are formed on the pair of front support protrusions 224 of the front support member (electrode holder) 22. The pair of base protrusions 144 a (see FIG. 4) inserted into the pair of front support holes (not shown) and formed on the pair of rear base protrusions 144 are the pair of rear support protrusions of the rear support member 24. It is inserted into a pair of rear support holes (not shown) formed in the portion 144.

  Subsequently, as shown in FIG. 10C, the inner upper cover 30 is attached to the front support member (electrode holder) 22 and the rear support member 24. At this time, the upper leaf spring 26 is sandwiched and fixed between the inner upper cover 30, the front support member (electrode holder) 22 and the rear support member 24.

  More specifically, the pair of upper end portions 264 in front of the upper leaf spring 26 is between the pair of locking projections 304 in front of the inner upper cover 30 and the pair of front support projections 224 of the front support member 22. It is clamped and fixed. Further, the pair of upper end portions 264 on the rear side of the upper leaf spring 26 are sandwiched between the pair of locking projections 304 on the rear side of the inner upper cover 30 and the pair of rear support projections 244 on the rear support member 24. And fixed.

  Finally, as shown in FIG. 10D, the outer upper cover 16 is put on the assembly shown in FIG. 10C.

  Thus, in the present embodiment, the lens driving device 10 can be manufactured step by step. As a result, the tact time until product completion can be shortened, and dust adhesion can be suppressed as much as possible.

  After that, as described above, the lens barrel 11 is attached to the lens holder 18.

  The lens driving device 10 according to the first embodiment described above has the following effects.

  Since the shape memory alloy wire 32 (SMA assembly 36) to which the pair of electrodes 34 are attached is attached to the actuator base 14 via the electrode holder 22, the shape of the actuator base 14 can be simplified.

  As shown in FIG. 10, since the lens driving device 10 can be manufactured step by step, the lens driving device 10 (product) can be easily disassembled when the characteristics are poor. As a result, the parts can be reused.

  A lens driving device 10A according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a perspective view of the lens driving device 10 </ b> A as viewed obliquely from above and in the state in which the lens barrel 11 and the outer upper cover 16 are omitted. FIG. 12 is a front view of the lens driving device 10A shown in FIG. FIG. 13 is a perspective view of the state in which the SMA assembly is attached to the electrode holder 22 as viewed obliquely from above and rearward.

  The illustrated lens driving device 10A has the same configuration as the lens driving device 10 shown in FIGS. 1 to 7 except that the configuration of the shape memory alloy member (SMA assembly) is different as will be described later. And work. Accordingly, reference numerals 32A and 36A are assigned to the shape memory alloy member and the SMA assembly, respectively. The same components as those of the lens driving device 10 are denoted by the same reference numerals, description thereof will be omitted, and only differences will be described below.

  The illustrated shape memory alloy member 32A is composed of a shape memory alloy member formed in a coil shape. The illustrated shape memory alloy member 32A has a length of 3 mm, for example, when it is not stretched (natural state). On the other hand, as shown in FIGS. 11 and 12, when the shape memory alloy member 32 </ b> A is stretched by hooking the intermediate portion 32 </ b> Aa on the protruding portion (holding protrusion) 184 of the lens holder 18, the shape memory is obtained. The length of the alloy member 32A is, for example, 7 mm. The thickness (diameter) of the wire of the shape memory alloy member 32 is 0.05 mm.

  Therefore, the shape memory alloy wire 32 formed in a linear shape contracts only about 4%, for example, whereas the shape memory alloy member 32A formed in a coil shape contracts, for example, 200% or more. Is possible. Therefore, compared with the lens driving device 10 according to the first embodiment, in the lens driving device 10A according to the second embodiment, the movable range (stroke) of the lens movable portion (11, 18) is increased. Can do.

  The lens driving device 10A having such a configuration operates in the same manner as the lens driving device 10 according to the first embodiment described above, and thus the description of the operation is omitted.

  In any case, the shape memory alloy member 32A expands and contracts in the direction of the optical axis O due to a temperature change caused by energization / non-energization, and functions as a moving unit that moves the lens holder 18 in the direction of the optical axis O.

  The combination of the elastic member 20 and the SMA assembly 36A is a lens driving unit (20, 20) that drives the lens moving unit (11, 18) while supporting the lens moving unit (11, 18) movably in the optical axis O direction. 36A).

  The lens driving unit (20, 36A) and the lens movable unit (11, 18) are juxtaposed with respect to the optical axis O as shown in FIG. Therefore, the lens driving device 10A can be reduced in height.

  The assembly method of the lens driving device 10A is the same as the assembly method of the lens driving device 10 described with reference to FIGS.

  The lens driving device 10A according to the second embodiment described above has the following effects.

  Since the shape memory alloy member 32A (SMA assembly 36A) to which the pair of electrodes 34 are attached is attached to the actuator base 14 via the electrode holder 22, the shape of the actuator base 14 can be simplified.

  Since the SMA assembly 36A is attached to the actuator base 14 via the electrode holder 22, the lens drive device 10A (product) can be easily disassembled when the characteristics are poor. As a result, the parts can be reused.

  Furthermore, since the shape memory alloy member 32A is formed in a coil shape, the total length of the wire of the shape memory alloy member 32A can be made longer than that of the linear shape memory alloy wire 32. Therefore, the elastic force of the shape memory alloy member 32A can be improved. As a result, the lens displacement amount (the stroke of the lens movable portion) of the lens driving device 10A can be significantly increased.

  A lens driving apparatus 10B according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 14 is a perspective view showing a lens holder and an SMA assembly used in the lens driving device according to the third embodiment of the present invention, and FIG. 15 is a lens driving device according to the third embodiment of the present invention. It is the disassembled perspective view which looked at from diagonally forward upper direction.

  The lens driving device 10B according to the third embodiment is shown in FIGS. 1 to 7 except that the configurations of the SMA assembly, the electrode holder, and the latching protrusion (projection) are different as will be described later. It has the same configuration as the lens driving device 10 of the first embodiment and operates. Therefore, the SMA assembly, the electrode holder, and the latching protrusion (protrusion) are denoted by reference numerals 36B-1, 36B-2, 22, 24B, and 184B-1, 184B-2, respectively. . The same components as those of the lens driving device 10 of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Hereinafter, the first embodiment and the third embodiment are omitted. Only the differences from this embodiment will be described.

  First, the latching protrusions (projections) 184B-1 and 184B-2, which are the first difference between the first embodiment and the third embodiment, will be described.

  In the lens driving device 10 according to the first embodiment, one latching protrusion (projection) 184 is provided, whereas in the lens driving device 10B according to the third embodiment, the latching projection (projecting portion) 184 is provided. Two protrusions (projections) 184B-1 and 184B-2 are provided.

  More specifically, in the lens driving device 10B according to the third embodiment, a pair of projecting portions 184B-1 projecting radially outward in front of the front-rear direction X on the outer peripheral wall of the cylindrical portion 182 of the lens holder 18. , 184B-2 are formed. The protruding part 184B-1 is formed in front of the cylindrical part 182 and the protruding part 184B-2 is formed in the rear of the cylindrical part 182. As shown in FIG. 14, the pair of protrusions 184B-1 and 184B-2 are formed at positions shifted from each other by 180 ° around the optical axis O located at the center of the cylindrical portion 182. In other words, the pair of projecting portions 184B-1 and 184B-2 are disposed symmetrically with respect to a plane that passes through the optical axis O and that is defined (extends) by the left-right direction Y and the up-down direction Z. Each protrusion part 184B-1 and 184B-2 protrudes in the hook shape along the up-down direction Z toward the lower end side from the upper end side of the cylindrical part 182. As shown in FIG. The protrusions 184B-1 and 184B-2 are for hooking intermediate portions 32B-1a and 32B-2a of shape memory alloy wires 32B-1 and 32B-2 formed in a coil shape, which will be described later. is there. Therefore, the protrusions 184B-1 and 184B-2 are also called latching protrusions.

  Next, the electrode holders 22 and 24B, which are the second difference between the first embodiment and the third embodiment, will be described.

  In the lens driving device 10 according to the first embodiment, only the front support member 22 functions as an electrode holder, whereas in the lens driving device 10B according to the third embodiment, only the front support member 22 is used. The rear support member 24B also functions as an electrode holder.

  More specifically, the housing (housing) 12 includes a front support member 22 and a rear support member 24B that function as electrode holders. Here, the front support member 22 in the third embodiment has the same configuration as that of the front support member 22 in the first embodiment, and a description thereof will be omitted. In addition, the rear support member 24B in the third embodiment has substantially the same configuration as the rear support member 24 in the first embodiment, and therefore the rear support member 24B and the first support member 24B in the third embodiment are the same. Only differences from the rear support member 24 in the embodiment will be described below, and the description of other configurations will be omitted.

  The rear support member 24B in the third embodiment functions as an electrode holder that holds a pair of electrodes 34B-2, and holds a held portion 342B-2 of a pair of electrodes 34B-2 described later on its back surface. It has a rear support connecting portion 246B. The rear support connecting portion 246B has a columnar first protrusion 246Ba that protrudes forward from the rear surface thereof so as to be fitted into the circular hole 342B-2a of the held portion 342B-2. Further, the rear support connecting portion 246B has a second protrusion 246Bb that protrudes forward from the back surface so as to be engaged with the bottom surface of the held portion 342B-2. Further, the rear support connecting portion 246B has a substantially triangular prism-shaped third protrusion 246Bc that protrudes rearward from the back surface thereof so as to engage with the L-shaped inner bent portion of the held portion 342B-2. The outer side surface of the held portion 342B-2 of the electrode 34B-2 is locked to the inner wall of the rear support protrusion 244B of the rear support member 24B.

  Next, SMA assemblies 36B-1, 36B-2 (shape memory alloy members 32B-1, 32B-2, electrodes 34B) which are the third difference between the first embodiment and the third embodiment. -1, 34B-2) will be described.

  In the lens driving device 10 according to the first embodiment, one SMA assembly 36 (shape memory alloy member 32, a pair of electrodes 34) is provided, whereas the lens according to the third embodiment. In the driving device 10B, two SMA assemblies 36B-1 and 36B-2 (shape memory alloy members 32B-1 and 32B-2, a pair of electrodes 34B-1 and 34B-2) are provided.

Specifically, the lens driving device 10B according to the third embodiment includes a first SMA assembly 36B-1 (a shape memory alloy member 32B-1, a pair of electrodes 34B-1), and the first SMA assembly. A second SMA assembly 36B-2 (a shape memory alloy member 32B-2 and a pair of electrodes 34B-2) configured in the same manner as 36B-1.
The held portion 342B-1 of the pair of electrodes 34B-1 constituting the first SMA assembly 36B-1 is held on the back surface of the front support connecting portion 226 of the electrode holder (front support member) 22. The held portion 342B-2 of the pair of electrodes 34B-2 constituting the second SMA assembly 36B-2 is held on the back surface of the rear support connecting portion 246B of the electrode holder (rear support member) 24B.

  Further, in the lens driving device 10 according to the first embodiment, the shape memory alloy member 32 is formed in a linear shape, whereas in the lens driving device 10B according to the third embodiment, the shape memory is provided. Alloy members 32B-1 and 32B-2 are formed in a coil shape.

  More specifically, the shape memory alloy members 32B-1 and 32B-2 of the third embodiment are constituted by shape memory alloy members formed in a coil shape. The illustrated shape memory alloy members 32B-1 and 32B-2 have a length of 3 mm, for example, when they are not stretched (natural state). On the other hand, as shown in FIG. 14, the shape memory alloy members 32B-1 and 32B-2 and the intermediate portions 32B-1a and 32B-2a thereof are projected portions (holding projections) 184B- of the lens holder 18. When hooked on 1, 184B-2 and stretched, the length of the shape memory alloy members 32B-1, 32B-2 is, for example, 7 mm. In addition, the thickness (diameter) of the wire rods of the shape memory alloy members 32B-1 and 32B-2 is 0.05 mm.

  Therefore, the shape memory alloy wire 32 of the first embodiment formed in a linear shape contracts, for example, only about 4%, whereas the shape memory of the third embodiment formed in a coil shape. In the alloy members 32B-1 and 32B-2, for example, it is possible to shrink 200% or more. Therefore, compared with the lens driving device 10 according to the first embodiment, in the lens driving device 10B according to the third embodiment, the movable range (stroke) of the lens movable portions 11 and 18 can be increased. .

  Since the lens driving device 10B having such a configuration operates in the same manner as the lens driving device 10 according to the first embodiment described above, description of the operation is omitted.

  In any case, the shape memory alloy members 32B-1 and 32B-2 contract due to temperature changes caused by energization / non-energization, and the lens holder 18 is moved to the optical axis via the protrusions (holding protrusions) 184B-1 and 184B-2. It works as a moving means for moving in the O direction.

  The combination of the elastic member 20 and the SMA assemblies 36B-1 and 36B-2 is a lens driving unit that drives the lens movable units 11 and 18 while supporting the lens movable units 11 and 18 movably in the optical axis O direction. Works as 20, 36B-1, 36B-2.

  The lens driving units 20, 36B-1, 36B-2 and the lens movable units 11, 18 are juxtaposed with respect to the optical axis O. Accordingly, the lens driving device 10B can be reduced in height.

  The assembling method of the lens driving device 10B of the third embodiment is also the same as the assembling method of the lens driving device 10 of the first embodiment described with reference to FIG. 8 to FIG. .

  The lens driving device 10B according to the third embodiment described above has the following effects.

  The shape memory alloy members 32B-1 and 32B-2 (SMA assemblies 36B-1 and 36B-2) to which the pair of electrodes 34B-1 and 34B-2 are attached are attached to the actuator base 14 via the electrode holders 22 and 24B. Since it is attached, the shape of the actuator base 14 can be simplified.

  Since the SMA assemblies 36B-1 and 36B-2 are attached to the actuator base 14 via the electrode holders 22 and 24B, the lens driving device 10B (product) can be easily disassembled when the characteristics are poor. As a result, the parts can be reused.

  Since the shape memory alloy members 32B-1 and 32B-2 are formed in a coil shape, the total length of the shape memory alloy members 32B-1 and 32B-2 is larger than that of the linear shape memory alloy wire 32. Can be lengthened. Therefore, the elastic force of the shape memory alloy members 32B-1 and 32B-2 can be improved. As a result, the lens displacement amount (the stroke of the lens movable portion) of the lens driving device 10B can be significantly increased.

  Further, two latching protrusions 184B-1 and 184B-2 are provided on the outer peripheral wall of the cylindrical portion 182 at equal angular intervals with the optical axis O as the center, and correspond to the latching protrusions 184B-1 and 184B-2. By providing two shape memory alloy members 32B-1 and 32B-2 (SMA assemblies 36B-1 and 36B-2), the two SMA assemblies 36B-1 and 36B-2 are movable parts 11 and 18. ) Is applied at two locations in the front-rear direction, so that the inclination of the lens movable portions 11 and 18 with respect to the optical axis O direction when the lens driving device 10B is movable can be suppressed.

  Further, since the lens movable parts 11 and 18 are driven by the two shape memory alloy members 32B-1 and 32B-2, the driving force required for each of the shape memory alloy members 32B-1 and 32B-2 is halved. However, since it is only necessary, a wider design freedom of the shape memory alloy members 32B-1 and 32B-2 can be secured.

  In the present embodiment, it has been described that there are two latching protrusions (protrusions) and two shape memory alloy members, but the number of latching protrusions (protrusions) and shape memory alloy members is as follows. Any of three, four, etc. may be used.

  A lens driving device 10C according to a fourth embodiment of the present invention will be described with reference to FIGS. 16 is a perspective view of the lens driving device according to the fourth embodiment of the present invention, with the outer upper cover omitted, and viewed obliquely from above. FIG. 17 shows the actuator from the lens driving device shown in FIG. FIG. 18 is a perspective view of the lens driving device according to the fourth embodiment of the present invention as viewed from the diagonally forward upper side, omitting the base, the elastic member, and the electrode holder. FIG. 19 is a front view of the lens driving device shown in FIG. 17, and FIG. 20 is a top view of the lens driving device shown in FIG.

  The lens driving device 10C of the fourth embodiment is different from the first embodiment shown in FIGS. 1 to 7 except that the lens holder, the lens driving unit, and the actuator base are different as will be described later. It has the same configuration as the lens driving device 10 of the embodiment and operates. Accordingly, the same components as those of the lens driving device 10 of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the following, the first embodiment and the fourth embodiment are omitted. Only differences from the embodiment will be described.

  First, the lens holder 18C which is the first difference between the first embodiment and the fourth embodiment will be described.

  The lens holder 18 in the lens driving device 10 according to the first embodiment has one latching protrusion (projection) 184 that latches the shape memory alloy wire 32, whereas The lens holder 18C in the lens driving device 10C according to the embodiment has two latching protrusions (projections) 184C-1 and 184C-2 that latch shape memory alloy wires 32C-1 and 32C-2 described later. Furthermore, urging latching protrusions (projections) 188C-1a, 188C-1b, 188C-2a, 188C-2b for latching urging shape memory alloys 38C-1 and 38C-2 described later are provided. There are four more.

First, the latching protrusions (projections) 184C-1 and 184C-2 will be described in detail below.
In the lens driving device 10C according to the fourth embodiment, a pair of latching protrusions 184C-1 projecting radially outward at the front and rear in the front-rear direction X on the outer peripheral wall of the cylindrical portion 182C of the lens holder 18C. 184C-2 is formed. The latching protrusion 184C-1 is formed in front of the cylindrical part 182C, and the latching protrusion 184C-2 is formed in the rear of the cylindrical part 182C. The pair of latching protrusions 184C-1 and 184C-2 are formed at positions shifted from each other by 180 ° around the optical axis O located at the center of the cylindrical portion 182C, as shown in FIGS. Has been. In other words, the pair of latching protrusions 184C-1 and 184C-2 are disposed symmetrically with respect to a plane that passes through the optical axis O and is defined by (extends in) the horizontal direction Y and the vertical direction Z. . Each of the latching protrusions 184C-1 and 184C-2 protrudes in a hook shape along the vertical direction Z from the upper end side to the lower end side of the cylindrical portion 182C. Each of the latching protrusions 184C-1 and 184C-2 is for latching intermediate portions 32C-1a and 32C-2a of the shape memory alloy wires 32C-1 and 32C-2 formed in a linear shape to be described later. It is.

Next, urging latching protrusions (projections) 188C-1a, 188C-1b, 188C-2a, and 188C-2b will be described in detail below.
Four urging latching projections 188C-1a, 188C-1b, 188C-2a, 188C-2b projecting radially outward at the front and rear in the front-rear direction X on the outer peripheral wall of the cylindrical portion 182C of the lens holder 18C. Is formed. Of the four urging latching protrusions 188C-1a, 188C-1b, 188C-2a, and 188C-2b, the pair of urging latching protrusions 188C-1a and 188C-1b are disposed in front of the cylindrical portion 182C. Is formed. The pair of urging latching protrusions 188C-2a and 188C-2b are formed behind the cylindrical portion 182C. The pair of urging latching projections 188C-1a and 188C-1b are positioned above the latching projection 184C-1 in a state where two in the left-right direction Y are aligned. More specifically, the pair of biasing projections 188C-1a and 188C-1b are positioned on a line extending upward along the vertical direction Z through the latching projection 184C-1. The urging latching protrusions 188C-1a and 188C-1b are arranged. Similarly, a pair of urging latching projections 188C-2a and 188C-2b are positioned above the latching projection 184C-2 in a state where two in the left-right direction Y are aligned. More specifically, the pair of biasing latching projections 188C-2a and 188C-2b are positioned on a line extending upward along the vertical direction Z through the latching projection 184C-2. The urging latching protrusions 188C-2a and 188C-2b are arranged. Each urging latching protrusion 188C-1a, 188C-1b, 188C-2a, 188C-2b protrudes in a hook shape along the vertical direction Z from the lower end side to the upper end side of the cylindrical portion 182C. The biasing protrusions 188C-1a, 188C-1b, 188C-2a, and 188C-2b are biased shape memory alloys 38C-1 and 38C-2 formed in a coil shape to be described later. -1a and 38C-2a.

  The lens holder 18C in the lens driving device 10C according to the fourth embodiment has an upper holder protrusion 186 that is formed in the lens holder 18 in the lens driving device 10 according to the first embodiment. Absent.

  Next, an actuator base 14C, which is the second difference between the first embodiment and the fourth embodiment, will be described.

  In the lens driving device 10 according to the first embodiment, the electrode holder 22 and the actuator base 14 are formed separately, whereas in the lens driving device 10C according to the fourth embodiment, The actuator base 14C has an electrode holding function.

  Specifically, the actuator base 14C of the fourth embodiment includes a ring-shaped base portion 142C, four first electrode holder portions 144C that protrude upward in the vertical direction Z at the four corners of the base portion 142C, Between the first electrode holder portions 144C, there are two second electrode holder portions 146C protruding upward in the vertical direction Z from the base portion 142C. The four first electrode holder portions 144C have substantially the same shape. The two second electrode holder portions 146C have substantially the same shape. The four first electrode holder portions 144C are for holding electrodes 34C-1 and 34C-2 described later and alloy holding portions 382C-1 and 382C-2 described later. The two second electrode holder portions 146C are for holding electrodes 34C-1 and 34C-2, which will be described later, and for positioning a lower leaf spring 28C, which will be described later, in the front-rear direction X and the left-right direction Y.

  Next, a lens driving unit which is the third difference between the first embodiment and the fourth embodiment will be described.

  In the lens driving device 10 according to the first embodiment, the lens driving unit is composed of a combination of the elastic member 20 and one shape memory alloy wire 32 for driving. In the lens driving device 10C according to the embodiment, the lens driving unit includes the elastic member 20C, the two shape memory alloy wires 32C-1 and 32C-2 for driving, and the two shape memory alloys 38C for urging. 1 and 38C-2.

First, the elastic member 20C will be described in detail below.
The elastic member 20C includes an upper leaf spring 26C disposed on the upper side of the lens holder 18C in the optical axis O direction and a lower leaf spring 28C disposed on the lower side of the lens holder 18C in the optical axis O direction. . The upper leaf spring 26C in the fourth embodiment and the upper leaf spring 26 in the first embodiment have the same functional aspects, although there are some differences in their configurations. Similarly, the lower leaf spring 28C in the fourth embodiment and the lower leaf spring 28 in the first embodiment have the same functional aspects, although there is a slight difference in configuration. That is, the upper leaf spring 26C and the lower leaf spring 28C are disposed between the lens holder 18C and the housing 12, and elastically support the lens holder 18C so as to be displaceable in the optical axis O direction in a state of being positioned in the radial direction. It functions as the member 20C. The upper leaf spring 26C and the lower leaf spring 28C are made of beryllium copper, phosphor bronze, or the like.

Next, the shape memory alloy wires 32C-1 and 32C-2 for driving will be described in detail below.
The shape memory alloy wire 32C-1 is held at both ends by a pair of electrodes 34C-1. The shape memory alloy wire 32C-2 is held at both ends by a pair of electrodes 34C-2. The intermediate portion 32C-1a of the shape memory alloy wire 32C-1 is hooked by a hooking projection (projecting portion) 184C-1. The shape memory alloy wire 32C-2 has its intermediate portion 32C-2a hooked by a hooking projection (projecting portion) 184C-2. The shape memory alloy wires 32C-1 and 32C-2 for driving are each formed in a linear shape, similarly to the shape memory alloy wire 32 in the first embodiment.

Next, the two urging shape memory alloys 38C-1 and 38C-2 will be described in detail below.
The urging shape memory alloy 38C-1 is disposed above the shape memory alloy wire 32C-1, and the urging shape memory alloy 38C-2 is disposed above the shape memory alloy wire 32C-2. A pair of alloy holding portions 382C-1 are attached to both ends of the urging shape memory alloy 38C-1. A pair of alloy holding portions 382C-2 are attached to both ends of the urging shape memory alloy 38C-2. The alloy holding portions 382C-1 are fitted and held in alloy holding grooves 144Ca formed in the two first electrode holder portions 144C located on the front side. The alloy holding portions 382C-2 are fitted and held in alloy holding grooves 144Ca formed in the two first electrode holder portions 144C located on the rear side. The urging shape memory alloy 38C-1 has its intermediate portion 38C-1a latched by two urging latching projections (projections) 188C-1a and 188C-1b. The urging shape memory alloy 38C-2 has its intermediate portion 38C-2a latched by two urging latching projections (projections) 188C-2a and 188C-2b. The urging shape memory alloys 38C-1 and 38C-2 are not connected to the electrodes and are not energized.

  The two urging shape memory alloys 38C-1 and 38C-2 are formed in a coil shape. The illustrated shape memory alloys 38C-1 and 38C-2 for urging have a length of 3 mm, for example, when they are not stretched (natural state). On the other hand, the shape memory alloys 38C-1 and 38C-2 for urging and the intermediate portions 38C-1a and 38C-2a are urging latching protrusions (projections) 188C-1a and 188C for the lens holder 18C. -1b, 188C-2a, 188C-2b, and when stretched, the urging shape memory alloys 38C-1 and 38C-2 have a length of, for example, 7 mm. In addition, the thickness (diameter) of the wire of the shape memory alloys 38C-1 and 38C-2 for urging is 0.05 mm.

  Therefore, when it is formed in a linear shape, for example, it contracts only about 4%, whereas when it is formed in a coil shape, it can contract, for example, 200% or more.

  The shape memory alloy wires 32C-1 and 32C-2 for driving and the shape memory alloys 38C-1 and 38C-2 for urging are shrunk when the temperature rises in a high temperature environment. Below, the temperature drops and expands. The “high temperature environment” mentioned here means an environment where the external temperature is about 70 ° C. or higher when, for example, a TiNi alloy is adopted as the shape memory alloy. The “normal temperature environment” means an environment where the external temperature is about 70 ° C. or less when, for example, a TiNi alloy is used as the shape memory alloy.

  Next, the operation of the lens driving unit under normal temperature environment, high temperature environment, and energization of the driving shape memory alloy wires 32C-1 and 32C-2 will be described below.

  First, in the normal temperature environment, the urging shape memory alloys 38C-1 and 38C-2 do not contract as described above, so that the lens movable parts 11 and 18C are moved downward along the optical axis O direction. As a result, it is possible to adjust the urging force for urging the lens movable portions 11 and 18C downward along the optical axis O direction.

  Next, in a high temperature environment, the shape memory alloy wires 32C-1 and 32C-2 contract as the temperature rises as described above. At this time, the urging shape memory alloys 38C-1 and 38C-2 are similarly contracted as their temperature rises. At this time, the lens movable parts 11, 18C are directed downward in the optical axis O direction from the thrust of the shape memory alloy wires 32C-1, 32C-2 acting on the lens movable parts 11, 18C toward the upper side in the optical axis O direction. Since the thrust of the urging shape memory alloys 38C-1 and 38C-2 acting on the lens increases (or becomes equal), the displacement of the lens movable portions 11 and 18C upward in the direction of the optical axis O can be prevented. As described above, the urging shape memory alloys 38C-1 and 38C-2 function as thrust adjusting means for adjusting the thrust acting on the lens movable portions 11 and 18C.

  Next, when the shape memory alloy wires 32C-1 and 32C-2 are energized, the shape memory alloy wires 32C-1 and 32C-2 contract as the temperature rises, and the latching protrusions (projections) 184C. The lens holder 18C is moved upward in the direction of the optical axis O via -1, 184C-2. At this time, since the urging shape memory alloys 38C-1 and 38C-2 are not energized as described above, they act only as urging springs that urge downward. As a result, the lens holder 18C moves upward along the optical axis O direction against the downward biasing force of the biasing shape memory alloys 38C-1, 38C-2 and the upper leaf spring 26C. On the other hand, when the energization to the shape memory alloy wires 32C-1 and 32C-2 is stopped, the shape memory alloy wires 32C-1 and 32C-2 are naturally cooled. As a result, the shape memory alloy wires 32C-1 and 32C-2 expand, and the lens holder 18C is moved in the optical axis O direction by the downward biasing force of the biasing shape memory alloys 38C-1 and 38C-2. Move down along.

  The lens driving device 10C according to the fourth embodiment described above has the following effects.

  Two latching protrusions (projections) 184C-1 and 184C-2 are provided on the outer peripheral wall of the cylindrical portion 182C at equal angular intervals with the optical axis O as the center, and the latch projections (projections) 184C-1, Corresponding to 184C-2, by providing two shape memory alloy wires 32C-1 and 32C-2, it is possible to apply a uniform propulsive force to the lens movable parts 11 and 18C at two locations in the front-rear direction. The inclination of the lens movable portions 11 and 18C with respect to the optical axis O direction when the lens driving device 10C is movable can be suppressed.

  Further, since the lens movable portions 11 and 18C are driven by the two shape memory alloy wires 32C-1 and 32C-2, the driving force required for each of the shape memory alloy wires 32C-1 and 32C-2 is halved. Therefore, it is possible to secure a wider design freedom of the shape memory alloy wires 32C-1 and 32C-2.

  In addition, since the urging shape memory alloys 38C-1 and 38C-2 are installed as the lens driving units, the lens movable units 11 and 18C are urged downward along the optical axis O direction in a normal temperature environment. In addition to being able to adjust the urging force, it is possible to prevent displacement of the lens movable portions 11 and 18C in the direction of the optical axis O in a high temperature environment.

  Further, since the shape memory alloys 38C-1 and 38C-2 for urging are formed in a coil shape, the shape memory for urging is caused by contraction of the shape memory alloy wires 32C-1 and 32C-2 in a high temperature environment. The shrinkage of the alloys 38C-1 and 38C-2 is increased, and the downward propulsive force along the optical axis O direction is increased. Can be prevented.

  With reference to FIGS. 21 to 26, a lens driving device 10D according to a fifth embodiment of the present invention will be described. FIG. 21 is a perspective view of the lens driving device according to the fifth embodiment of the present invention when the outer upper cover is omitted and viewed obliquely from above, and FIG. 22 is an actuator from the lens driving device shown in FIG. FIG. 23 is a perspective view of the lens driving device according to the fifth embodiment of the present invention as viewed from the diagonally forward upper side, omitting the base, the elastic member, and the electrode holder, and FIG. FIG. 24 is a front view of the lens driving device shown in FIG. 22, FIG. 25 is a side view of the lens driving device shown in FIG. 22, and FIG. 26 is shown in FIG. It is a top view of a lens drive device.

  The lens driving device 10D of the fifth embodiment is shown in FIGS. 16 to 20 except that the structures of the urging latching protrusion and the urging shape memory alloy are different as will be described later. It has the same configuration as the lens driving device 10C of the fourth embodiment and operates. Therefore, the same components as those of the lens driving device 10C according to the fourth embodiment are denoted by the same reference numerals, and the description thereof is omitted. Hereinafter, the fourth embodiment and the fifth embodiment are omitted. Only differences from the embodiment will be described.

  First, the biasing protrusions 188D-1 and 188D-2, which are the first difference between the fourth embodiment and the fifth embodiment, will be described.

  The biasing projections 188C-1a and 188C-1b in the lens driving device 10C according to the fourth embodiment are positioned above the latching projections 184C-1, while the fifth embodiment. The biasing protrusion 188D-1 for urging in the lens driving device 10D according to the embodiment is formed above a position shifted by 90 ° about the optical axis O from the position of the locking protrusion 184C-1. Similarly, the urging latching protrusions 188C-2a and 188C-2b in the lens driving device 10C according to the fourth embodiment are positioned above the latching protrusion 184C-2. The urging latching protrusion 188D-2 in the lens driving device 10D according to the fifth embodiment is formed above a position that is shifted by 90 ° about the optical axis O from the position of the latching protrusion 184C-2. . The urging latching protrusion 188D-1 and the urging latching protrusion 188D-2 are formed at positions shifted from each other by 180 ° with the optical axis O as the center.

  Next, urging shape memory alloys 38D-1 and 38D-2 which are the second difference between the fourth embodiment and the fifth embodiment will be described.

  In the lens driving device 10C according to the fourth embodiment, the urging shape memory alloy 38C-1 is disposed above the shape memory alloy wire 32C-1, and the urging latching protrusions 188C-1a, 188C- In contrast, in the lens driving device 10D according to the fifth embodiment, the urging shape memory alloy 38D-1 is shifted by 90 ° from the position of the shape memory alloy wire 32C-1 while being hung on 1b. It is arranged above the position and is hung on the aforementioned urging latching projection 188D-1. Similarly, in the lens driving device 10C according to the fourth embodiment, the urging shape memory alloy 38C-2 is disposed above the shape memory alloy wire 32C-2 and is applied to the urging latching protrusion 188C-2a. In contrast, in the lens driving device 10D according to the fifth embodiment, the urging shape memory alloy 38D-2 is 90 from the position of the shape memory alloy wire 32C-2. It is arranged above the position deviated and hung on the above-mentioned urging latching projection 188D-2. The urging shape memory alloy 38D-1 and the urging shape memory alloy 38D-2 are disposed at positions shifted from each other by 180 ° about the optical axis O. One of the pair of alloy holding portions 382D-1 attached to both ends of the urging shape memory alloy 38C-1 is one first electrode of the two first electrode holder portions 144C located on the front side. The other of the pair of alloy holding portions 382D-1 is fitted and held in the alloy holding groove 144Ca formed in the holder portion 144C, and the other of the two first electrode holder portions 144C located on the rear side Is fitted and held in an alloy holding groove 144Ca formed in one of the first electrode holder portions 144C. Similarly, one of the pair of alloy holding portions 382D-2 attached to both ends of the urging shape memory alloy 38C-2 is one of the two first electrode holder portions 144C located on the front side. Two first electrode holder portions that are fitted and held in an alloy holding groove 144Ca formed in one electrode holder portion 144C and the other of the pair of alloy holding portions 382D-2 is located on the rear side It is fitted and held in an alloy holding groove 144Ca formed in one first electrode holder portion 144C of 144C.

  The lens driving device 10D according to the fifth embodiment described above is compared with the lens driving device 10C according to the fourth embodiment in the installation positions and biases of the shape memory alloy wires 32C-1 and 32C-2. Since the shape memory alloys 38D-1 and 38D-2 are separated from each other, the assembling work of the lens driving device 10D can be easily achieved.

  In the present embodiment, the shape memory alloy wires 32C-1 and 32C-2 and the urging shape memory alloys 38D-1 and 38D-2 are disposed at positions shifted by 90 ° with respect to the optical axis O. However, this angle may be any value.

  Although the present invention has been particularly shown and described with reference to the embodiments thereof, the present invention is not limited to these embodiments. It will be understood by those skilled in the art that various modifications can be made in form and detail without departing from the spirit and scope of the invention as defined in the claims. For example, in the present invention, the SMA assembly is not directly attached to the actuator base, but is attached to the actuator base via the electrode holder. Therefore, if a mechanism capable of adjusting the position of the electrode holder is used, the shape memory alloy member It is possible to easily adjust the amount of tension applied to the shape memory alloy member even after it is attached to the housing. As a result, it is possible to suppress variations in product characteristics. Further, the guide means (elastic member) is not limited to the above-described embodiment, and various types may be used.

10, 10A, 10B, 10C, 10D Lens drive device 11 Lens barrel (lens assembly)
12 Housing (housing)
14, 14C Actuator base 142, 142C Base portion 144 Base protrusion 146 Front recess 148 Front recess 144C First electrode holder portion 144Ca Alloy holding groove 146C Second electrode holder portion 16 Outer upper cover 18, 18C Lens holder 182, 182C Cylindrical part 184, 184B-1, 184B-2, 184C-1, 184C-2 Protruding part (holding protrusion)
186 Upper holder protrusion 186a Upper holder protrusion 188C-1a, 188C-1b, 188C-2a, 188C-2b, Energizing latch protrusion (protrusion)
20, 20C elastic member 22 front support member (first support member; electrode holder)
222 Front base portion 224 Front support protrusion 224a Front support protrusion 226 Front connection portion 226a First protrusion 226b Second protrusion 226c Third protrusion 24, 24B Rear support member (second support member)
242 Back base part 244, 244B Back support protrusion 244a Back support protrusion 246, 246B Back connection part 26, 26C Upper leaf spring 262 Upper ring part 262a Upper spring hole
264 Upper end portion 264a Upper end portion hole 266 Upper arm portion 28, 28C Lower leaf spring 282 Lower arc portion 284 Lower end portion 284a Lower end portion hole 286 Lower arm portion 30 Inner upper cover (stopper)
302 Inner cover body 304 Locking protrusion 304a Through hole 306 Front extension 308 Back extension 32, 32A, 32B-1, 32B-2, 32C-1, 32C-2 Shape memory alloy wires 32a, 32Aa, 32B -1a, 32B-2a, 32C-1a, 32C-2a Intermediate part 34, 34B-1, 34B-2, 34C-1, 34C-2 Electrode 342, 342B-1, 342B-2 Held part 342a, 342B- 2a Circular hole 344 Connection portion 346 Terminal portion 36, 36A, 36B-1, 36B-2 SMA assembly 38C-1, 38C-2, 38D-1, 38D-2 Energizing shape memory alloy 382C-1, 382C-2 Alloy holder O Optical axis of lens AFL Autofocus lens

Claims (15)

A lens holder including a cylindrical portion that holds a lens barrel; a housing that supports the lens holder so as to be movable only in the optical axis direction; a moving means that moves the lens holder in the optical axis direction; and the lens holder. In a lens driving device provided with guide means that guides movement only in the optical axis direction,
The moving means includes a shape memory alloy member stretched between the lens holder and the housing, and both ends of the shape memory alloy member are attached with a pair of electrodes for energizing it,
The housing includes an actuator base disposed on a lower side of the lens holder, and an electrode holder that is attached to the actuator base and holds the pair of electrodes.
A lens driving device.   2. The lens driving device according to claim 1, wherein the lens holder has a latching protrusion that projects radially outward from the cylindrical portion and latches an intermediate portion of the shape memory alloy member.   The guide means includes an elastic member disposed between the lens holder and the housing, and the elastic member supports the lens holder so as to be displaceable only in the optical axis direction with the lens holder positioned in a radial direction. The lens driving device according to claim 1 or 2.   The said elastic member is comprised from the upper side leaf | plate spring and lower side leaf | plate spring which were each provided in the optical axis direction upper side and lower side of the cylindrical part of the said lens holder, Each of Claim 1 thru | or 3 comprised. Lens drive device.   The upper leaf spring includes an upper ring portion that is attached to the upper end portion of the lens holder, four upper end portions that are attached to the housing, and four upper portions that connect the upper ring portion and the four upper end portions, respectively. The lens driving device according to claim 4, further comprising an arm portion. The lower leaf spring is composed of a pair of lower leaf springs,
Each of the pair of lower leaf springs includes a lower arc portion attached to a lower end portion of the lens holder, a pair of lower end portions fixed to the housing, the lower arc portion, and the pair of lower sides The lens driving device according to claim 4, further comprising a pair of lower arm portions connecting the end portions.   The lens drive device according to claim 1, wherein the shape memory alloy member is formed of a shape memory alloy wire formed in a linear shape.   The lens drive device according to any one of claims 1 to 6, wherein the shape memory alloy member is formed of a shape memory alloy member formed in a coil shape. A plurality of the latching protrusions are arranged on the outer peripheral wall of the cylindrical portion at equiangular intervals around the optical axis,
9. The lens driving device according to claim 2, wherein the shape memory alloy member is arranged in the same number as the number of the hooking protrusions and is hooked on the hooking protrusions. A first step of attaching an upper leaf spring and a lower leaf spring to both ends in the optical axis direction of a lens holder having a cylindrical portion for holding a lens barrel;
A second step of attaching a support member having a shape memory alloy assembly attached to the lens holder;
A third step of attaching an actuator base to the support member in a state of sandwiching the lower leaf spring from the bottom side of the lens holder;
A fourth step of attaching an inner upper cover to the support member in a state of sandwiching the upper leaf spring from the upper side of the lens holder;
A fifth step of covering the outer upper cover so as to cover the inner upper cover;
A method of assembling a lens driving device. The shape memory alloy assembly includes a shape memory alloy member and a pair of electrodes electrically connected to both ends of the shape memory alloy member,
The lens holder has first and second sides facing each other, and has a latching projection protruding outward from the outer wall of the cylindrical portion on the first side,
The support member includes a first support member and a second support member that are installed to face each other, and the shape memory alloy assembly is attached to the first support member while holding the pair of electrodes. And
The second step includes
The shape memory alloy member is stretched between the lens holder and the first support member by engaging an intermediate portion of the shape memory alloy member with the latch protrusion, and the first support Attaching a member to the first side of the lens holder;
Attaching the second support member to the second side of the lens holder;
The method for assembling a lens driving device according to claim 10, comprising: The upper leaf spring includes an upper ring portion, four upper end portions provided at four corners and having upper spring holes, and four upper arm portions connecting the upper ring portion and the four upper end portions. ,
The lower leaf spring includes a pair of lower leaf springs, and each of the pair of lower leaf springs includes a lower arc portion, a pair of lower end portions having a lower end hole, and the lower arc portion. And a pair of lower arms connecting the pair of lower ends,
The first step includes
Attaching the upper ring portion of the upper leaf spring to the upper end of the cylindrical portion of the lens holder;
Attaching the front lower side arc portion of the pair of lower leaf springs to the lower end of the cylindrical portion of the lens holder;
The method for assembling the lens driving device according to claim 11, comprising: Each of the first and second support members includes a pair of support protrusions at both ends thereof, each of the pair of support protrusions has a support protrusion at the upper end,
The second step includes a step of fitting the support protrusions of the first and second support members into the upper end holes of the four upper end portions of the upper leaf spring, respectively.
The method for assembling the lens driving device according to claim 12. The actuator base has a ring-shaped base portion and four base protrusion portions protruding upward at four corners of the base portion, and the four base protrusion portions are respectively four base protrusions protruding upward. Have a protrusion,
In the third step, the four base protrusions formed on the four base projecting portions of the actuator base are respectively formed on the lower sides formed on the pair of lower end portions of the pair of lower leaf springs. The four base protrusions of the actuator base are attached to the pair of support protrusions of the first and second support members, respectively, through the end holes.
The method for assembling the lens driving device according to claim 13. The inner upper cover has a ring-shaped inner cover body and four locking protrusions protruding downward at the four corners of the inner cover body, and each of the four locking protrusions has a through hole. Have
In the fourth step, the support protrusions of the first and second support members projecting through the upper end holes of the four upper end portions of the upper leaf spring are respectively connected to the 4 of the inner upper cover. Attaching the inner upper cover to the first and second support members in a state of being inserted into the through holes formed in the two locking projections;
The method for assembling the lens driving device according to claim 14.

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