JP2011175160A - Lens driving device - Google Patents

Abstract

A sufficient lens displacement amount is ensured.
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 single shape memory alloy member 32 that extends substantially around the outer periphery of the lens holder 18 and is stretched between the lens holder 18 and the housing 12. The lens holder 18 is disposed so as to protrude radially outward from the cylindrical portion 182 at equal angular intervals of (360 ° / N) (N is an integer of 2 or more) with the optical axis O as the center. N holder / hook portions 184 for latching the alloy member 32 are included.
[Selection] Figure 1

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.

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

  For example, WO 2007/113478 A1 (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 incorporates a subassembly having an SMA wire connected to at least one attachment member attached to 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 in which SMA wires are connected by caulking. The attachment member is electrically connected to the SMA wire. Therefore, the attachment member serves as an electrode. The attachment member (electrode) is attached to a recess formed in the support structure (annular wall).

  Japanese Patent Application Laid-Open No. 2007-292864 (Patent Document 2) discloses a “lens driving device” in which transmission efficiency is improved and downsizing is achieved. 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.

  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.

  Japanese Patent Laying-Open No. 2009-19507 (Patent Document 3) discloses a “driving module” that can reduce variations in assembly 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.

  Japanese Patent Laying-Open No. 2009-128736 (Patent Document 4) discloses a “drive module” that reduces the possibility of breakage or failure due to impact force due to dropping or the like, and can be downsized. Yes.

  The drive module disclosed in Patent Document 4 includes a lens frame, a module frame housed inside the lens frame, an upper leaf spring, and the lens frame against a biasing force of the upper leaf spring in a certain direction. And an SMA wire that is driven along. A guide protrusion is provided on the outer side in the radial direction of the lens frame so as to protrude outward in the radial direction. A notch is formed at the bottom of one corner of the module frame. The groove width in plan view of the notch has such a size as to be fitted to the guide projection of the lens frame so as to be movable in the axial direction. A pair of locking grooves are provided at two corners adjacent to the cutout of the module frame. The pair of locking grooves are for attaching a pair of wire holding members for holding the SMA wire on the side surface on the same direction side as the corner where the notch is provided. The SMA wire whose both ends are held by the pair of wire holding members is locked from below to the tip key portion of the guide protrusion of the lens frame protruding from the notch of the module frame.

  Japanese Patent Laying-Open No. 2006-98829 (Patent Document 5) discloses a “lens driving device” that can move a lens smoothly and quickly and is miniaturized so that it can be incorporated into a portable information terminal. ing.

  The lens driving device disclosed in Patent Document 5 includes a front coil spring and a rear coil spring that are arranged in contact with each other to urge the lens frame from the front side and the rear side in the optical axis direction. At least one of the front coil spring and the rear coil spring is made of a shape memory alloy. In Patent Document 5, it is described that both the front coil spring and the rear coil spring may be made of a shape memory alloy. And when both the front side coil spring and the rear side coil spring are made of shape memory alloy, when one is energized and heated, the other is energized and overheated, and it should be configured to contract. Yes. That is, both the front coil spring and the rear coil spring act as drive springs.

WO2007 / 113478A1 (FIG. 2) JP 2007-292864 A JP 2009-19507 A JP 2009-128736 A (FIG. 3, [0023] to [0026]) Japanese Patent Laying-Open No. 2006-98829 ([0030])

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

  In the camera lens driving device disclosed in Patent Document 1, two SMA wires are held by an attachment member. Therefore, the length of each SMA wire cannot be increased, and it is difficult to ensure a sufficient amount of lens displacement.

  In the lens driving device disclosed in Patent Document 2, one SMA wire is disposed only on one side of the fixed barrel. Therefore, the length of the SMA wire cannot be increased, and it is difficult to ensure a sufficient amount of lens displacement.

  Also in the drive module disclosed in Patent Document 3, one shape memory alloy (SMA) wire is disposed only on one side of the driven body (lens holder). Therefore, the length of the SMA wire cannot be increased, and it is difficult to ensure a sufficient amount of lens displacement.

  In the drive module disclosed in Patent Document 4, one SMA wire is disposed on two side surfaces of the module frame. Therefore, the length of the SMA wire cannot be increased, and it is difficult to ensure a sufficient amount of lens displacement.

  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.

  Note that Patent Document 5 merely discloses that both the front coil spring and the rear coil spring may be used as drive springs.

  Therefore, the subject of this invention is providing the lens drive device which can ensure sufficient lens displacement amount.

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

  According to the present invention, the lens holder (18; 18A) including the cylindrical portion (182) that holds the lens barrel (11), and the lens holder (18; 18A) can be moved only in the optical axis (O) direction. The housing (12; 12A) supported by the lens, the moving means for moving the lens holder (18; 18A) in the optical axis (O) direction, and the lens holder (18; 18A) can be moved only in the optical axis (O) direction. In the lens driving device (10; 10A; 10B; 10C) provided with the guiding means, the moving means extends substantially once around the outer periphery of the lens holder (18; 18A), and The lens holder (18; 18A) includes a single shape memory alloy member (32; 32A; 32B) stretched between the lens holder (18; 18A) and the housing (10; 10A; 10B; 10C). Is One shape memory alloy arranged to protrude radially outward from the cylindrical portion (182) at equal angular intervals of (360 ° / N) (N is an integer of 2 or more) with the optical axis (O) as the center A lens driving device including N holder hook portions (184; 184A) for engaging the members (32; 32A; 32B) is obtained.

  In the lens driving device (10; 10A; 10B; 10C) according to the present invention, the moving means is attached to both end portions of one shape memory alloy member (32; 32A; 32B), respectively. You may further have a pair of electrode (34; 34A) for supplying with electricity to an alloy member (32; 32A; 32B). The housing (12; 12A) includes an actuator base (14; 14A) disposed on the lower side of the lens holder (18; 18A), and the actuator base (14; 14A) includes a pair of electrodes (34; 34A) may be included. The electrode holding part (146a; 146Ab, 149Ab) may be included.

  In the lens driving device (10; 10A; 10B) according to the first aspect of the present invention, N is equal to 2, the housing (12) has a substantially bottomed rectangular tube shape, and an electrode holding portion. (146a) may be formed in a protrusion (146) protruding upward from the actuator base (14) at the first four corners of the housing (12). In this case, the housing (12) has two first corners of the four corners of the housing (12) opposite to the first corner on the first diagonal passing orthogonally through the optical axis (O). Including a housing hook portion (148a) for hooking the shape memory alloy member (32; 32A; 32B), and the two holder hook portions (184) pass perpendicularly to the optical axis (O). In addition, it is preferable that the lens holder (18) is formed on the second diagonal line intersecting the first diagonal line.

  In the lens driving device (10C) according to the second aspect of the present invention, N is equal to 2, the housing (12A) has a substantially bottomed rectangular tube shape, and the actuator base (14A) is And four sliding protrusions (146A; 147A; 148A; 149A) protruding upward at the four corners of the housing (12A) and slidingly contacting one shape memory alloy member (32; 32A; 32A). Good. In this case, the electrode holding portion (146Ab; 149Ab) is formed on a pair of sliding contact protrusions (146A; 149A) adjacent to each other on the first side surface side of the housing (12A) among the four sliding contact protrusions. The two holder hook portions (184A) are parallel to the first side surface of the housing (12A) and on a straight line passing through the optical axis (O) at right angles to the lens holder (18A). It is preferable to be formed.

  In the lens driving device (10; 10C) of the present invention, one shape memory alloy member may be composed of one shape memory alloy wire (32) formed in a linear shape.

  In the lens driving device (10A) of the present invention, one shape memory alloy member (32A) has a plurality of shape memory alloy wires (32-1; 32-2; 32- 3). The plurality of shape memory alloy wires (32-1; 32-2; 32-3) are preferably twisted.

  In the lens driving device (10B) of the present invention, one shape memory alloy member may be composed of one shape memory alloy member (32B) formed in a coil shape.

  In the lens driving device (10; 10A; 10B; 10C) according to the present invention, the guide means is, for example, an elastic member (26, 18A) disposed between the lens holder (18; 18A) and the housing (12; 12A). 28; 26A, 28A). In this case, the elastic members (26, 28; 26A, 28A) support the lens holder (18; 18A) so as to be displaceable only in the optical axis (O) direction with the lens holder (18; 18A) positioned in the radial direction. The elastic members are an upper leaf spring (26; 26A) and a lower leaf spring (28; provided on the upper and lower sides, respectively, in the optical axis (O) direction of the cylindrical portion (182) of the lens holder (18; 18A). 28A).

  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, since one shape memory alloy member which is a moving means extends so as to substantially make one round of the outer periphery of the lens holder, the length of the shape memory alloy wire can be increased, A sufficient amount of lens displacement can be ensured.

It is the disassembled 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. It is the perspective view which looked at the state which extended and attached the SMA assembly used for the lens drive device shown in FIG. 1 with respect to the lens holder from the front right upper part. It is the perspective view which looked at the state shown in FIG. 2 from the upper left rear. It is the disassembled perspective view which looked at the external appearance of the lens drive device by the 2nd Embodiment of this invention from diagonally forward upper direction. It is the perspective view which looked at the state which extended and attached the SMA assembly used for the lens drive device shown in FIG. 4 with respect to the lens holder from the front right upper part. It is an enlarged view which expands and shows the A section of FIG. It is an expanded sectional view which expands and shows the B section of FIG. It is a top view which shows the state which wound three shape memory alloy wires. It is sectional drawing about line IX-IX of FIG. It is the disassembled perspective view which looked at the external appearance of the lens drive device by the 3rd Embodiment of this invention from diagonally forward upper direction. It is the perspective view which looked at the external appearance of the lens drive device by the 4th Embodiment of this invention from diagonally forward upper direction. It is the perspective view which looked at the lens drive device shown in FIG. 11 from diagonally forward upper direction in the state which excluded the outer side upper cover. It is the disassembled perspective view which looked at the lens drive device shown in FIG. 11 from diagonally forward upper direction. It is the perspective view which looked at the state where the SMA assembly used for the lens drive device shown in FIG. It is the perspective view which looked at the state shown in FIG. 14 from the left rear upper direction. It is the perspective view which looked at the external appearance of the lens drive device by the 5th Embodiment of this invention from diagonally forward upper direction. It is the disassembled perspective view which looked at the lens drive device shown in FIG. 16 from diagonally forward upper direction. It is the perspective view which looked at the lens drive device shown in FIG. 16 from diagonally forward upper direction, omitting an outer upper cover and an upper leaf spring. FIG. 19 is a perspective view of the lens driving device shown in FIG. 18 as viewed from diagonally forward above, omitting the actuator base and the lower leaf spring.

  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 FIG. FIG. 1 is an exploded perspective view of the lens driving device 10 as viewed obliquely from above and front.

  Here, as shown in FIG. 1, an orthogonal coordinate system (X, Y, Z) is used. In the state illustrated in FIG. 1, 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 the Z-axis direction is The vertical direction (height direction). In the example shown in FIG. 1, the vertical direction Z is the direction of the optical axis O of the lens.

  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 passes through an optical axis O at right angles to a plane defined by (extends to) a first diagonal direction passing through the vertical direction Z and the front right and rear left. It has a plane-symmetric structure.

  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.

  The housing 12 has four corners. Here, of these four corners, the right front corner is called a first corner, and the left rear corner is called a second corner.

  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 182 a is cut on the inner peripheral wall of the cylindrical portion 182 of the lens holder 18. On the other hand, a male screw 11 a 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.

  The outer peripheral wall of the cylindrical portion 182 of the lens holder 18 passes through the optical axis O orthogonally and intersects (orthogonally) the first diagonal direction (that is, passes through the left front and the right rear). Two holder hook portions 184 projecting radially outward in two diagonal directions (FIG. 1 shows only one holder hook portion at the left front). These two holder hook portions 184 are for hooking one shape memory alloy wire 32 formed in a linear shape to be described later.

  In other words, the pair of projecting portions (holder / hook portions) 184 are arranged in a radial direction from the cylindrical portion 182 at equal angular intervals of 180 ° about the optical axis O (facing in the second diagonal direction). It is arranged to protrude outward.

  The actuator base 14 includes a ring-shaped base portion 142 and first to fourth base protruding portions 146, 147, 148, and 149 that protrude upward in the vertical direction Z at the four corners of the base portion 142. The first base protrusion 146 is provided at the right front corner, the second base protrusion 147 is provided at the left front corner, the third base protrusion 148 is provided at the left rear corner, and the fourth base. The protrusion 149 is provided at the right rear corner. Accordingly, the first base protruding portion 146 and the third base protruding portion 148 are arranged on the opposite side (opposite) on the first diagonal line with the optical axis O in between.

  The first base protruding portion 146 includes an electrode holding portion 146a for holding a pair of electrodes 34 to be described later. On the other hand, the third base protrusion 148 includes a housing hook 148a for hooking the one shape memory alloy wire 32.

  Accordingly, the electrode holding portion 146 a is formed at the first corner of the housing 12, and the housing hook portion 148 a is formed at the second corner of the housing 12.

  The lens driving device 10 includes an upper leaf spring 26 and a lower leaf spring 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 lower leaf spring 28 are disposed between the lens holder 18 and the housing 12 and support the elastic member 20 so as to be displaceable in the optical axis O direction with the lens holder 18 positioned in the radial direction. Work as.

  Further, as described above, in the 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 referred to as a front spring, and the lower leaf spring 28 is also referred to as a rear spring.

  The upper leaf spring 26 is disposed above the lens holder 18 in the optical axis O direction, and the lower leaf spring 28 is disposed below the lens holder 18 in the optical axis O direction. The upper leaf spring 26 and the lower leaf spring 28 have substantially the same configuration.

  The upper leaf spring 26 has an inner peripheral end 262 attached to the lens holder 18 and an outer peripheral end 264 attached to the housing 12 as will be described later. A plurality of arm portions (not shown) provided along the circumferential direction are provided between the inner peripheral side end portion 262 and the outer peripheral side portion 264 in order to connect them. The inner peripheral end 262 has an annular shape. The outer peripheral end 264 is provided apart from the inner peripheral end 262 and has an octagonal ring shape larger than the inner peripheral end 262. Each arm portion extends along the circumferential direction.

  The inner peripheral side end 262 of the upper leaf spring 26 is fixed to the upper end of the cylindrical portion 182 of the lens holder 18.

  On the other hand, the outer peripheral side end 264 of the upper leaf spring 26 is fixed to the housing 12 as described later. Specifically, the housing 12 further includes a resin inner upper cover 30 provided inside the outer upper cover 16. The inner upper cover 30 fixes the outer peripheral end 264 of the upper leaf spring 26.

  Therefore, the housing 12 includes the actuator base 14, the outer upper cover 16, and the inner upper cover 30.

  Similarly, the lower leaf spring 28 has an inner peripheral end 282 attached to the lens holder 18 and an outer peripheral end 284 attached to the housing 12 as will be described later. A plurality of arm portions (not shown) provided along the circumferential direction are provided between the inner peripheral side end portion 282 and the outer peripheral side portion 284 in order to connect them. The inner peripheral side end 282 has an annular shape. The outer peripheral end 284 is provided apart from the inner peripheral end 282 and has an octagonal ring shape larger than the inner peripheral end 282. Each arm portion extends along the circumferential direction.

  The inner peripheral side end 282 of the lower leaf spring 28 is fixed to the lower end side of the cylindrical portion 182 of the lens holder 18 by the adhesive force of the resin. On the other hand, the outer peripheral side end portion 284 of the lower leaf spring 28 is fixed to the base portion 142 of the actuator base 14 of the housing 12.

  The inner peripheral side end portions 262 and 282 are also called inner rings, and the outer peripheral side end portions 264 and 284 are also called outer rings.

  The elastic member 20 including the upper leaf spring 26 and the lower leaf spring 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 lower leaf spring 28 is made of metal such as beryllium copper, phosphor bronze, and stainless steel. The plate springs 26 and 28 are manufactured by pressing a predetermined thin plate or etching using a photolithography technique. Note that the etching process is more preferable than the press process. This is because no residual stress remains in the leaf spring 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 includes a single shape memory alloy wire 32 formed in a linear shape extending so as to substantially go around the outer periphery of the cylindrical portion 182 of the lens holder 18, and the shape memory alloy wire 32. And a pair of electrodes 34 respectively electrically connected to both ends. One shape memory alloy wire 32 is stretched between the lens holder 18 and the housing 12. In the illustrated example, the diameter (thickness) of one shape memory alloy wire 32 is 36 μm. 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 pair of electrodes 34 is held by an electrode holding portion 146 a formed on the first base protruding portion 146.

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

  On the other hand, the electrode holding portion 146a formed on the first base protruding portion 146 includes a groove for slidingly holding the terminal portion 344 of each electrode 34 and a through hole through which the terminal portion 344 passes.

  Next, a state in which the SMA assembly 36 is stretched and attached to the lens holder 18 will be described with reference to FIGS. FIG. 2 is a perspective view of the state in which the SMA assembly 36 is attached to the lens holder 18 as viewed from the upper right front. FIG. 3 is a perspective view of the state in which the SMA assembly 36 is attached to the lens holder 18 by stretching the SMA assembly 36 from the upper left rear.

  As shown in FIG. 2, each electrode 34 is held by an electrode holding portion 146 a (FIG. 1) formed on the first base protruding portion 146. One shape memory alloy wire 32 is hooked by two holder / hook portions 184 formed on the second diagonal of the lens holder 18.

  On the other hand, as shown in FIG. 3, one shape memory alloy wire 32 is hooked on a housing hook portion 148 a formed on the third base protruding portion 148.

  In this way, 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 32 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 FIGS. Therefore, the lens driving device 10 can be reduced in height.

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

  The first effect is that a sufficient amount of lens displacement can be ensured. The reason is that one shape memory alloy wire 32 is extended so as to substantially circulate the outer periphery of the lens holder 18, so that the entire length of the shape memory alloy wire 32 can be increased. .

  The second effect is that the lens tilt can be reduced. The reason is that one shape memory alloy wire 32 is hooked by two holder hook portions 184 formed on the second diagonal passing through the lens holder 18 perpendicular to the optical axis O. This is because the driving force of the lens holder 18 can be uniformly applied in the optical axis O direction (focus direction).

  In the first embodiment, one shape memory alloy wire 32 is used as one shape memory alloy member. However, the present invention is not limited to this. For example, as one shape memory alloy member, a plurality of shape memory alloy wires as shown in the second embodiment described later may be used, or shown in the third embodiment described later. A single shape memory alloy member formed in a coil shape may be used.

  A lens driving device 10A according to a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is an exploded perspective view of the lens driving device 10A as viewed obliquely from above and front.

  The illustrated lens driving device 10A is the same as the lens driving device 10 shown in FIGS. 1 to 3 except that the configuration of one shape memory alloy member (SMA assembly) is different as will be described later. It has a structure and operates. 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.

  FIG. 5 is a perspective view of the state in which the SMA assembly 36 </ b> A is stretched and attached to the lens holder 18 as viewed from the upper right front. FIG. 6 is an enlarged view showing an A portion of FIG. FIG. 7 is an enlarged cross-sectional view showing a portion B of FIG.

  As shown in FIG. 6, the illustrated shape memory alloy member 32A includes three shape memory alloy wires 32-1, 32-2, and 32-3, each formed in a linear shape.

  As described above, in the lens driving device 10A according to the second embodiment, the three shape memory alloy wires 32-1, 32-2, and 32-3 are bundled and used as a driving source. , Durability during lens driving can be improved. For example, in the lens driving device 10 using one shape memory alloy wire 32 shown in FIG. 1, it is assumed that A [N] stress is applied to the shape memory alloy wire 32 during lens driving. In this case, in the lens driving device 10A using the three shape memory alloy wires 32-1, 32-2, and 32-3 shown in FIG. 4, the stress relating to the shape memory alloy member 32A is dispersed, and each shape The memory alloy wires 32-1, 32-1, or 32-3 can have a stress dispersion effect of A / 3 [N].

  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 single 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 means for moving 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 section (20, 36A) and the lens movable section (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 lens driving device 10A according to the second embodiment described above has the following effects.

  The first effect is that a sufficient amount of lens displacement can be ensured. The reason is that since one shape memory alloy member 32A is extended so as to substantially make one round of the outer periphery of the lens holder 18, the entire length of the shape memory alloy member 32A can be increased. .

  The second effect is that the lens tilt can be reduced. The reason is that one shape memory alloy member 32A is hooked by two holder hook portions 184 formed on the second diagonal passing through the lens holder 18 perpendicular to the optical axis O. This is because the driving force of the lens holder 18 can be uniformly applied in the optical axis O direction (focus direction).

  A third effect is that durability during lens driving can be improved. The reason is that since one shape memory alloy member 32A is composed of three shape memory alloy wires 32-1, 32-2 and 32-3, stress can be dispersed.

  In addition, as shown in FIG. 8, one shape memory alloy member 32A may be configured with three shape memory alloy wires 32-1, 32-2, and 32-3. FIG. 8 is a plan view showing a state in which the three shape memory alloy wires 32-1, 32-2, and 32-3 are held. FIG. 9 is a sectional view taken along line IX-IX in FIG.

  In the second embodiment, one shape memory alloy member 32A is composed of three shape memory alloy wires 32-1, 32-2, and 32-3. N may be an integer of 2 or more) shape memory alloy wires 32-1 to 32-N.

  A lens driving device 10B according to a third embodiment of the present invention will be described with reference to FIG. FIG. 10 is an exploded perspective view of the lens driving device 10B as viewed obliquely from above and front.

  The illustrated lens driving device 10B is the same as the lens driving device 10 shown in FIGS. 1 to 3 except that the configuration of one shape memory alloy member (SMA assembly) is different as will be described later. It has a structure and operates. Accordingly, the reference numerals 32B and 36B 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 32B is composed of one shape memory alloy member formed in a coil shape. The illustrated shape memory alloy member 32B has a length of, for example, 10 mm when not stretched (natural state). On the other hand, when the shape memory alloy member 32B is hooked on the two holder / hook portions 184 and stretched, the length of the shape memory alloy member 32B is, for example, 30 mm. The thickness (diameter) of the wire rod of the shape memory alloy member 32B is 36 μm.

  Therefore, one shape memory alloy wire 32 formed in a linear shape contracts, for example, only about 4%, whereas in one shape memory alloy member 32B formed in a coil shape, for example, 200 % Or more can shrink. 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 portion (11, 18) is increased. Can do.

  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, one shape memory alloy member 32B 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 means for moving the lens holder 18 in the direction of the optical axis O.

  The combination of the elastic member 20 and the SMA assembly 36B 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. 36B).

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

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

  The first effect is that a sufficient amount of lens displacement can be ensured. The reason is that since one shape memory alloy member 32B is extended so as to substantially make one round of the outer periphery of the lens holder 18, the entire length of the shape memory alloy member 32B can be increased. .

  The second effect is that the lens tilt can be reduced. The reason is that one shape memory alloy member 32B is hooked by two holder hook portions 184 formed on the second diagonal passing through the lens holder 18 perpendicular to the optical axis O. This is because the driving force of the lens holder 18 can be uniformly applied in the optical axis O direction (focus direction).

  A third effect is that the lens displacement amount (the stroke of the lens movable portion) of the lens driving device 10B can be significantly increased. The reason is that since the single shape memory alloy member 32B is formed in a coil shape, the total length of the wire of the shape memory alloy member 32B can be made longer than that of the linear shape memory alloy wire 32. This is because the elastic force of the shape memory alloy member 32B can be improved.

  A lens driving device 10C according to a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a perspective view of the external appearance of the lens driving device 10C as viewed obliquely from above and front. FIG. 12 is a perspective view of the lens driving device 10C as viewed obliquely from above and in the state where the outer upper cover 16A is omitted. FIG. 13 is an exploded perspective view of the lens driving device 10C as viewed obliquely from above and front.

  Here, as shown in FIGS. 11 to 13, an orthogonal coordinate system (X, Y, Z) is used. 11 to 13, 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 examples shown in FIGS. 11 to 13, the vertical direction Z is the direction of the optical axis O of the lens.

  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 </ b> C has a structure that is plane-symmetric 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.

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

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

  The outer upper cover 16A has a substantially rectangular tube shape. That is, the outer upper cover 16A has a right wall surface 161, a left wall surface 162, a front wall surface 163, and a rear wall surface 164. The outer upper cover 16A has an upper wall surface 165 having a circular opening 165a at the upper end thereof. In the present specification, the right wall surface 161 is also referred to as a first side surface.

  On the other hand, although not shown, an image sensor arranged on the substrate is mounted at the center of the actuator base 14A. 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 </ b> C includes a lens holder 18 </ b> A that holds the lens barrel 11. In other words, the lens barrel 11 is held and fixed in the lens holder 18A. More specifically, the lens holder 18A includes a cylindrical portion 182 having a substantially cylindrical shape. A female screw 182a is cut on the inner peripheral wall of the cylindrical portion 182 of the lens holder 18A. On the other hand, a male screw 11 a 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 18A, the lens barrel 11 is rotated around the optical axis O and screwed along the optical axis O direction with respect to the lens holder 18A. It is accommodated in the lens holder 18A and joined together by an adhesive or the like.

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

  On the outer peripheral wall of the cylindrical portion 182 of the lens holder 18A, a pair of projecting portions 184A projecting radially outward at the front and rear in the front-rear direction X (however, only the front projecting portion 184A is shown in FIG. 1). Have. The pair of projecting portions 184A project along the vertical direction Z from the upper end to the lower end of the cylindrical portion 182. The pair of projecting portions 184A are for hooking one shape memory alloy wire 32 formed in a linear shape to be described later. Therefore, each protrusion 184A is also called a latching protrusion or a holder hook part.

  In other words, the pair of projecting portions (holder / hook portions) 184A are radially outward from the tubular portion 182 at equal angular intervals of 180 ° about the optical axis O (opposite in the front-rear direction X). Protrusively arranged. That is, the two holder hook portions 184A are formed in the lens holder 18A on a straight line that is parallel to the first side surface 161 of the housing 12A and passes through the optical axis O at right angles.

  The actuator base 14A includes a ring-shaped base portion 142 and first to fourth base protruding portions 146A, 147A, 148A, and 149A that protrude upward in the vertical direction Z at the four corners of the base portion 142. The first base protrusion 146A is provided at the right front corner, the second base protrusion 147A is provided at the left front corner, the third base protrusion 148A is provided at the left rear corner, and the fourth base The protruding portion 149A is provided at the right rear corner.

  As will be described later, the first to fourth base protrusions 146A to 149A have first to fourth sliding contact portions 146Aa to 149Aa that are in sliding contact with one shape memory alloy wire 32. Accordingly, the first to fourth base protrusions 146A to 149A are also referred to as first to fourth sliding contact protrusions, respectively.

  The first base protrusion (sliding protrusion) 146A is a first electrode holding portion 146Ab for holding one of a pair of electrodes 34 to be described later on the first side surface (right wall surface 161) side of the housing 12A. including. In addition, the fourth base protrusion (sliding protrusion) 149A is a second electrode holding portion 149Ab for holding the other of the pair of electrodes 34 on the first side surface (right wall surface 161) side of the housing 12A. including.

  That is, the electrode holding portions 146Ab and 149Ab are formed on the pair of sliding contact protrusions 146A and 149A adjacent to each other on the first side surface 161 side of the housing 12A among the four sliding contact protrusions 146A to 149A. .

  The lens driving device 10C includes an upper leaf spring 26A and a lower leaf spring 28A provided on the upper and lower sides of the cylindrical portion 182 of the lens holder 18A in the optical axis O direction, respectively. The upper leaf spring 26A and the lower leaf spring 28A are arranged between the lens holder 18A and the housing 12A, and support the elastic member 20A so as to be displaceable in the optical axis O direction with the lens holder 18A positioned in the radial direction. Work as.

  Further, as described above, in the 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 26A is also referred to as a front spring, and the lower leaf spring 28A is also referred to as a rear spring.

  The upper leaf spring 26A is disposed on the upper side of the lens holder 18A in the optical axis O direction, and the lower leaf spring 28A is disposed on the lower side of the lens holder 18A in the optical axis O direction.

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

  The upper ring portion 262A of the upper leaf spring 26A is fixed to the cylindrical portion 182 of the lens holder 18A. Specifically, the lens holder 18 </ b> A has four upper holder protrusions 182 b that protrude upward from the upper end of the cylindrical part 182. The upper ring portion 262A of the upper leaf spring 26A has four upper spring holes 262Aa into which the four upper holder protrusions 182b are respectively inserted.

  On the other hand, the four upper end portions 264A of the upper leaf spring 26A are fixed to the first to fourth base protruding portions 146A to 149A. More specifically, each of the first to fourth base protrusions 146A to 149A includes four support protrusions protruding upward (two support protrusions 146Ac formed on the first and third base protrusions 146A and 148A). 148Ac only shown). The four upper ends 264A of the upper leaf spring 26A have four upper end holes 264Aa into which the four support protrusions formed on the first to fourth base protrusions 146A to 149A are inserted, respectively.

  The housing 12A further includes a resin inner upper cover 30A provided inside the outer upper cover 16A. A bias spring 38 is disposed between the inner upper cover 30A and the upper leaf spring 26A. The bias spring 38 is for urging the lens holder 18A downward in the vertical direction Z. In other words, the bias spring 38 is for applying a downward back tension to the lens holder 18A. The bias spring 38 includes a ring portion 382 having the same diameter as the upper ring portion 262A of the upper leaf spring 26, and four biasing spring portions 384 extending obliquely upward from the ring portion 382.

  Accordingly, the four upper end portions 264A of the upper leaf spring 26A are fixed by the inner upper cover 30A and the bias spring 38.

  Accordingly, the housing 12A includes the actuator base 14A, the outer upper cover 16A, and the inner upper cover 30A.

  The lower leaf spring 28A has a lower ring portion 282A attached to the lens holder 18A and four lower end portions 284A attached to the housing 12A as will be described later. Four lower arm portions 286 are provided between the lower ring portion 282A and the four lower end portions 284A. That is, the four lower arm portions 286 connect the lower ring portion 282A and the four lower end portions 284A.

  The lower ring portion 282A of the lower leaf spring 28A is fixed to the cylindrical portion 182 of the lens holder 18A. Specifically, the lens holder 18 </ b> A has four lower holder protrusions (not shown) that protrude downward from the lower end of the cylindrical portion 182. The lower ring portion 282A of the lower leaf spring 28A has four lower spring holes 282Aa into which the four lower holder protrusions are respectively inserted.

  On the other hand, the four lower end portions 284A of the lower leaf spring 28A are fixed to the base portion 142 of the actuator base 14A. More specifically, the base portion 142 has four support protrusions 142a (only two support protrusions are shown) protruding upward. Each of the four lower end portions 284A of the lower leaf spring 28A has four lower end hole 284Aa into which the four support protrusions 142 formed in the base portion 142 are fitted.

  The elastic member 20A composed of the upper leaf spring 26A and the lower leaf spring 28A serves as a guide means for guiding the lens holder 18A so as to be movable only in the direction of the optical axis O. Each of the upper leaf spring 26A and the lower leaf spring 28A is made of metal such as beryllium copper, phosphor bronze, and stainless steel. The plate springs 26A and 28A are manufactured by pressing a predetermined thin plate or etching using a photolithography technique. Note that the etching process is more preferable than the press process. This is because etching does not leave residual stress in the leaf spring.

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

  The lens driving device 10 </ b> C includes a single shape memory alloy wire 32 formed in a linear shape and extending so as to substantially go around the outer periphery of the cylindrical portion 182 of the lens holder 18 </ b> A, and the shape memory alloy wire 32. And a pair of electrodes 34A electrically connected to both ends. The combination of the shape memory alloy (SMA) wire 32 and the pair of electrodes 34A is referred to as a shape memory alloy (SMA) assembly 36C. The pair of electrodes 34A is held by first and second electrode holding portions 146Ab and 149Ab formed on the first base protruding portion 146A and the fourth base protruding portion 149A, respectively.

  The pair of electrodes 34A have a symmetrical shape when viewed from the Y-axis direction. The pair of electrodes 34A extends substantially in the up-down direction Z. Each electrode 34A has a strip-shaped terminal portion 342A extending in the vertical direction Z, and a connection portion 344 bent in a U-shaped cross section at the upper end portion of the terminal portion 342A. Each electrode 34 </ b> A is electrically connected to the end of the shape memory alloy wire 32 by caulking the connection portion 344. The terminal portion 342A is for receiving a drive current from a drive circuit (not shown). The terminal portion 342A has a widened portion 342Aa.

  On the other hand, each of the first and second electrode holding portions 146Ab and 149Ab formed on the first and fourth base protruding portions 146A and 149A holds the widened portion 342Aa of the terminal portion 344A of the electrode 34A in sliding contact. It consists of a groove.

  Next, a state in which the SMA assembly 36C is stretched and attached to the lens holder 18A will be described with reference to FIGS. FIG. 14 is a perspective view of the state in which the SMA assembly 36C is stretched and attached to the lens holder 18A, as viewed from the upper right front. FIG. 15 is a perspective view of the state in which the SMA assembly 36C is stretched and attached to the lens holder 18A, as viewed from the upper left rear.

  As shown in FIG. 14, the pair of electrodes 34A is held by the first and second electrode holding portions 146Ab and 149Ab formed on the first and fourth base protrusions 146A and 149A. In addition, one shape memory alloy wire 32 is hooked by two holder / hook portions 184A disposed opposite to each other in the front-rear direction X through the optical axis O of the lens holder 18A.

  On the other hand, as shown in FIGS. 14 and 15, one shape memory alloy wire 32 slides on the first to fourth sliding contact portions 146Aa to 149Aa of the first to fourth base protruding portions 146A to 149A. It touches.

  In this way, the shape memory alloy wire 32 is stretched between the lens holder 18A and the housing 12A.

  Next, a schematic operation of the lens driving device 10C 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 20A supports the lens holder 18A so as to be displaceable in the optical axis O direction in a state where the lens holder 18A is positioned in the radial direction. The bias spring 38 acts to urge the lens holder 18A downward along the optical axis O direction. On the other hand, the shape memory alloy wire 32 contracts when energized via a pair of electrodes 34A from a drive circuit (not shown). As a result, the lens holder 18A moves upward along the direction of the optical axis O against the downward biasing force of the bias spring 38.

  On the other hand, when the energization to the shape memory alloy wire 32 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 bias spring 38. As a result, the lens holder 18A 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 18A in the direction of the optical axis O.

  The combination of the elastic member 20A, the bias spring 38, and the SMA assembly 36C is a lens drive that drives the lens movable portion (11, 18A) while supporting the lens movable portion (11, 18A) movably in the optical axis O direction. Part (20A, 38, 36C).

  The lens driving unit (20A, 38, 36C) and the lens movable unit (11, 18A) are juxtaposed with respect to the optical axis O as shown in FIG. Therefore, the height of the lens driving device 10C can be reduced.

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

  The first effect is that a sufficient amount of lens displacement can be ensured. The reason is that one shape memory alloy wire 32 is extended so as to substantially make one round of the outer periphery of the lens holder 18A, so that the entire length of the shape memory alloy wire 32 can be increased. .

  The second effect is that the lens tilt can be reduced. The reason is that one shape memory alloy wire 32 is hooked by two holder hook portions 184A formed on opposite sides through the optical axis O of the lens holder 18A. This is because the driving force can be uniformly applied in the optical axis O direction (focus direction).

  In the fourth embodiment, one shape memory alloy wire 32 is used as one shape memory alloy member. However, the present invention is not limited to this. For example, one shape memory alloy member is composed of a plurality of shape memory alloy wires 32-1 to 32-3 as shown in the second embodiment described with reference to FIGS. One shape memory alloy member 32A may be used, or one shape memory alloy member formed in a coil shape as shown in the third embodiment described with reference to FIG. 32B may be used.

  By using one shape memory alloy member 32A composed of a plurality of shape memory alloy wires 32-1 to 32-3, durability during lens driving can be improved. Further, by using one shape memory alloy member 32B formed in a coil shape, the lens displacement amount (the stroke of the lens movable portion) of the lens driving device 10C can be greatly increased.

  A lens driving device 10D according to a fifth embodiment of the present invention will be described with reference to FIGS. FIG. 16 is a perspective view of the external appearance of the lens driving device 10D as viewed obliquely from above and front. FIG. 17 is an exploded perspective view of the lens driving device 10D as viewed obliquely from above and front. FIG. 18 is a perspective view of the lens driving device 10D as viewed obliquely from above and from the upper front cover and the upper leaf spring. FIG. 19 is a perspective view of the lens driving device shown in FIG. 18 as viewed obliquely from above, omitting the actuator base and the lower leaf spring.

  Here, as shown in FIGS. 16 to 19, an orthogonal coordinate system (X, Y, Z) is used. 16 to 19, 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 examples shown in FIGS. 16 to 19, the vertical direction Z is the direction of the optical axis O of the lens.

  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 10D has a structure that is plane-symmetric 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.

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

  As illustrated in FIG. 17, the lens driving device 10 </ b> D includes a substantially rectangular parallelepiped housing (housing) 12 </ b> B that covers the lens barrel 11. In other words, the lens barrel 11 is disposed in the housing (housing) 12B. The housing (housing) 12B includes an actuator base 14B and an upper cover 16B.

  The upper cover 16B has a substantially rectangular tube shape. That is, the upper cover 16B has a right wall surface 161A, a left wall surface 162A, a front wall surface 163A, and a rear wall surface 164A. The upper cover 16B has an upper wall surface 165A having a circular opening 165Aa at the upper end. In the present specification, the right wall surface 161A is also referred to as a first side surface.

  On the other hand, although not shown, an image sensor disposed on the substrate is mounted at the center of the actuator base 14B. 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 </ b> D includes a lens holder 18 </ b> B that holds the lens barrel 11. In other words, the lens barrel 11 is held and fixed in the lens holder 18B. More specifically, the lens holder 18B 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 18B. On the other hand, a male screw 11 a 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 18B, the lens barrel 11 is rotated around the optical axis O with respect to the lens holder 18B and screwed along the optical axis O direction. It is accommodated in the lens holder 18B and joined together by an adhesive or the like.

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

  On the outer peripheral wall of the cylindrical portion 182 of the lens holder 18B, a pair of projecting portions 184B projecting radially outward at the front and rear in the front-rear direction X (however, only the front projecting portion 184B is shown in FIG. 17). Have. The pair of projecting portions 184 </ b> B project along the vertical direction Z from the upper end to the lower end of the cylindrical portion 182. The pair of projecting portions 184B are for hooking one shape memory alloy wire 32 formed in a linear shape to be described later. Therefore, each protrusion 184B is also called a latching protrusion or a holder hook part.

  In other words, the pair of projecting portions (holder / hook portions) 184B are radially outward from the cylindrical portion 182 at equal angular intervals of 180 ° centered on the optical axis O (opposite in the front-rear direction X). Protrusively arranged.

  The actuator base 14B includes a ring-shaped base portion 142 and first to fourth base protruding portions 146B, 147B, 148B, and 149B that protrude upward in the vertical direction Z at the four corners of the base portion 142. The first base protrusion 146B is provided at the right front corner, the second base protrusion 147B is provided at the left front corner, the third base protrusion 148B is provided at the left rear corner, and the fourth base The protruding portion 149B is provided at the right rear corner.

  The first base protruding portion 146B includes a first electrode holding portion 146Ba for holding one of a pair of electrodes 34B described later on the front surface of the housing 12B on the first side surface (right wall surface 161A) side. The fourth base protrusion 149B includes a second electrode holding portion 149Ba for holding the other of the pair of electrodes 34B on the rear surface of the housing 12B on the first side surface (right wall surface 161A) side.

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

  Further, as described above, in the 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 26B is also referred to as a front spring, and the lower leaf spring 28B is also referred to as a rear spring.

  The upper leaf spring 26B is disposed on the upper side in the optical axis O direction of the lens holder 18B, and the lower leaf spring 28B is disposed on the lower side in the optical axis O direction of the lens holder 18B.

  The upper leaf spring 26B has an inner peripheral end 262 attached to the lens holder 18B and an outer peripheral end 264B attached to the inner wall of the upper wall surface 165A of the upper cover 16B. A plurality of arm portions (not shown) provided along the circumferential direction are provided between the inner peripheral side end portion 262 and the outer peripheral side portion 264B in order to connect them. The inner peripheral end 262 has an annular shape. The outer peripheral side end 264 </ b> B is provided to be spaced radially outward from the inner peripheral side end 262. The inner peripheral end of the outer peripheral end 264B is substantially circular, and the outer peripheral end is rectangular. Each arm portion extends along the circumferential direction.

  The inner peripheral side end 262 of the upper leaf spring 26B is fixed to the upper end of the cylindrical portion 182 of the lens holder 18B. On the other hand, as described above, the outer peripheral side end 264B of the upper leaf spring 26B is attached to the inner wall of the upper wall surface 165A of the upper cover 16B.

  Similarly, the lower leaf spring 28B has an inner peripheral end 282 attached to the lens holder 18B and an outer peripheral end 284B attached to the actuator base 14B. A plurality of arm portions (not shown) provided along the circumferential direction are provided between the inner peripheral side end portion 282 and the outer peripheral side portion 284 </ b> B in order to connect them. The inner peripheral side end 282 has an annular shape. The outer peripheral side end portion 284B includes a ring portion 284Ba provided to be spaced radially outward from the inner peripheral side end portion 282, and four extensions extending from the ring portion 284Ba outward in the front, rear, left, and right directions in the radial direction. And an exit portion 284Bb.

  An inner peripheral side end 282 of the lower leaf spring 28B is fixed to the lower end side of the cylindrical portion 182 of the lens holder 18B by a resin adhesive force. On the other hand, the outer peripheral side end 284B of the lower leaf spring 28B is fixed on the base portion 142 of the actuator base 14B of the housing 12B.

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

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

  The lens driving device 10D includes a single shape memory alloy wire 32 formed in a linear shape and extending so as to substantially go around the outer periphery of the cylindrical portion 182 of the lens holder 18B, and the shape memory alloy wire 32. And a pair of electrodes 34B electrically connected to both ends. The combination of a shape memory alloy (SMA) wire 32 and a pair of electrodes 34B is referred to as a shape memory alloy (SMA) assembly 36D. The pair of electrodes 34B is held by first and second electrode holding portions 146Ba and 149Ba formed on the first base protruding portion 146B and the fourth base protruding portion 149B, respectively.

  The pair of electrodes 34B has a symmetrical shape when viewed from the Y-axis direction. The pair of electrodes 34B extends substantially in the up-down direction Z. Each electrode 34B has a strip-shaped terminal portion 342B extending in the up-down direction Z, and a connection portion 344A bent in a U-shaped cross section at the upper end portion of the terminal portion 342B. Each electrode 34B is electrically connected to the end of the shape memory alloy wire 32 by caulking the connecting portion 344A. The terminal portion 342B is for receiving a drive current from a drive circuit (not shown).

  On the other hand, each of the first and second electrode holding portions 146Ba and 149Ba formed on the first and fourth base protruding portions 146B and 149B is constituted by a groove for slidingly holding the terminal portion 342B of each electrode 34B. Has been.

  The lens holder 18B includes a first pair of urging latching protrusions 186 for latching a first urging shape memory alloy member 41, which will be described later, and a second urging shape memory alloy member 42, which will be described later. A second pair of biasing latching projections 187 for latching is further provided.

  The first pair of urging latching projections 186 project radially outward in front of the front-rear direction X on the outer peripheral wall of the cylindrical portion 182 of the lens holder 18B. The first pair of biasing protrusions 186 for urging are positioned above the front holder / hook portion 184 </ b> B in a state where two urging latching projections 186 are arranged in the left-right direction Y. More specifically, the first pair of biasing projections 186 for biasing are positioned on a line extending upward along the vertical direction Z through the holder / hook portion 184B on the front side. A pair of urging latching protrusions 186 are arranged. Each of the first pair of urging latching projections 186 protrudes in a hook shape along the vertical direction Z from the lower end side to the upper end side of the cylindrical portion 182. The first pair of urging latching protrusions 186 is for latching the intermediate portion 41a of the first urging shape memory alloy member 41 formed in a coil shape to be described later.

  On the other hand, the second pair of urging latching projections 187 protrudes radially outward at the rear in the front-rear direction X on the outer peripheral wall of the cylindrical portion 182 of the lens holder 18B. The second pair of urging latching projections 187 are arranged above the rear holder / hook portion 184B in a state where two urging latching projections 187 are arranged in the left-right direction Y. More specifically, the second pair of biasing projections 187 for biasing is positioned on a line extending upward along the vertical direction Z through the rear holder / hook portion 184B. A pair of urging latching protrusions 187 are arranged. Each of the second pair of urging latching protrusions 187 protrudes in a hook shape along the vertical direction Z from the lower end side to the upper end side of the cylindrical portion 182. The second pair of urging latching protrusions 187 is for latching an intermediate portion 42a of a second urging shape memory alloy member 42 formed in a coil shape to be described later.

  The first urging shape memory alloy member 41 is disposed on the front upper side of the lens holder 18B, and the second urging shape memory alloy member 42 is disposed on the rear upper side of the lens holder 18B.

  The first urging shape memory alloy member 41 has a first pair of alloy holding portions 412 attached to both ends thereof. The first pair of alloy holding portions 412 are fitted and held in alloy holding grooves 146Bb and 147Bb respectively formed in the first and second base protrusions 146B and 147B located on the front side. As described above, the first urging shape memory alloy member 41 has its intermediate portion 41a latched by the first pair of urging latching projections 186. The first urging shape memory alloy member 41 is not connected to the electrode and is not energized.

  Similarly, the second energizing shape memory alloy member 42 has a second pair of alloy holding portions 422 attached to both ends thereof. The second pair of alloy holding portions 422 are fitted and held in alloy holding grooves 148Bb and 149Bb respectively formed in the third and fourth base protrusions 148B and 149B located on the rear side. As described above, the second urging shape memory alloy member 42 has its intermediate portion 42a latched by the second pair of urging latch projections 187. The second urging shape memory alloy member 42 is not connected to the electrode and is not energized.

  Each of the first and second urging shape memory alloys 41 and 42 is formed in a coil shape. Each of the illustrated first and second urging shape memory alloys 41 and 42 has a length of, for example, 3 mm when not stretched (natural state). On the other hand, the first and second urging shape memory alloys 41 and 42 are hooked on the urging latching protrusions (projections) 186 and 187 of the lens holder 18B, respectively. When stretched, the lengths of the first and second urging shape memory alloys 41 and 42 are each 7 mm, for example. In addition, the thickness (diameter) of the wire of the first and second urging shape memory alloys 41 and 42 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 one shape memory alloy wire 32 for driving and the first and second urging shape memory alloys 41 and 42 increase in temperature and contract in a high temperature environment. In, the temperature decreases 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, an outline of the operation of the lens driving device 10D in a room temperature environment 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 single shape memory alloy wire 32 shown in the drawing contracts to a pre-stored contraction length when self-heating is caused by energization, and when the energization is stopped, the original length predetermined by natural cooling (the length of the relaxed state). This is the type of wire that goes back to (a).

  The elastic member 20B supports the lens holder 18B so as to be displaceable in the optical axis O direction with the lens holder 18B positioned in the radial direction. The elastic member 20B and the first and second urging shape memory alloys 41 and 42 act to urge the lens holder 18B 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 34B from a drive circuit (not shown). As a result, the lens holder 18B moves upward along the optical axis O direction against the downward biasing force of the elastic member 20B and the first and second biasing shape memory alloys 41, 42.

  On the other hand, when the energization to the shape memory alloy wire 32 is stopped, the shape memory alloy wire 32 is naturally cooled. As a result, the shape memory alloy wire 32 is stretched by the downward biasing force of the elastic member 20B and the first and second biasing shape memory alloys 41,. As a result, the lens holder 18B 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 means for moving the lens holder 18B in the direction of the optical axis O.

  The combination of the elastic member 20B, the first and second urging shape memory alloys 41, 42, and the SMA assembly 36D allows the lens movable portion (11, 18B) to be supported while being movable in the optical axis O direction. It works as a lens driving part (20B, 41, 42, 36D) for driving the movable part (11, 18B).

  The lens driving unit (20B, 41, 42, 36D) and the lens movable unit (11, 18B) are juxtaposed with respect to the optical axis O as shown in FIG. Accordingly, the lens driving device 10D can be reduced in height.

  Next, the operation of the lens driving unit will be described in a normal temperature environment, a high temperature environment, and when the shape memory alloy wire 32 for driving is energized.

  First, since the first and second urging shape memory alloys 42 and 42 do not contract as described above in a room temperature environment, the lens movable portion (11, 18B) is moved in the direction of the optical axis O. As a result, the biasing spring that biases the lens movable portion (11, 18B) downward along the optical axis O direction can be adjusted.

  Next, in a high temperature environment, the shape memory alloy wire 32 contracts as its temperature rises as described above. At this time, the first and second urging shape memory alloys 41 and 42 similarly increase in temperature and contract. Accordingly, the thrust of the shape memory alloy wire 32 acting on the lens movable portion (11, 18B) toward the upper side in the optical axis O direction acts on the lens movable portion (11, 18B) toward the lower side in the optical axis O direction. Since the thrusts of the first and second urging shape memory alloys 41 and 42 increase (or become equal), the displacement of the lens movable portion (11, 18B) in the upward direction in the optical axis O direction can be prevented. Thus, the first and second urging shape memory alloys 41 and 42 are thrust adjusting means (thrust compensating means) for adjusting (compensating) the thrust acting on the lens movable portion (11, 18B) in a high temperature environment. ). In other words, the first and second biasing shape memory alloys 41 and 42 function as temperature compensation means.

  Next, when one shape memory alloy wire 32 is energized, the temperature of the shape memory alloy wire 32 increases and contracts, and a lens holder is interposed via a pair of latching protrusions (holder / hook portions) 184B. 18B is moved upward in the direction of the optical axis O. At this time, since the first and second urging shape memory alloys 41 and 42 are not energized as described above, they act only as urging springs that urge downward. As a result, the lens holder 18B moves upward along the optical axis O direction against the downward biasing force of the elastic member 20B and the first and second biasing shape memory alloys 41, 42. On the other hand, when the energization to the shape memory alloy wire 32 is stopped, the shape memory alloy wire 32 is naturally cooled. As a result, the shape memory alloy wire 32 expands, and the lens holder 18B moves in the direction of the optical axis O by the downward biasing force of the elastic member 20B and the first and second biasing shape memory alloys 41 and 42. Move down along.

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

  The first effect is that a sufficient amount of lens displacement can be ensured. The reason is that one shape memory alloy wire 32 is extended so as to substantially circulate around the outer periphery of the lens holder 18B, so that the entire length of the shape memory alloy wire 32 can be increased. .

  The second effect is that the lens tilt can be reduced. The reason is that one shape memory alloy wire 32 is hooked by two holder hook portions 184B formed on the opposite sides through the optical axis O of the lens holder 18B. This is because the driving force can be uniformly applied in the optical axis O direction (focus direction).

  The third effect is that the displacement of the lens movable portion (11, 18B) in the direction of the optical axis O can be prevented (compensated) in a high temperature environment. The reason is that the first and second urging shape memory alloy members 41 and 42 functioning as temperature compensating means are installed as the lens driving unit.

  The fourth effect is that the displacement of the lens movable portion (11, 18B) in the optical axis O direction can be reliably prevented under a high temperature environment. The reason is that the first and second urging shape memory alloy members 41 and 42 acting as temperature compensating means are formed in a coil shape, so that the shape memory alloy wire 32 for driving contracts in a high temperature environment. This is because the contraction of the first and second urging shape memory alloy members 41 and 42 becomes larger, and the downward driving force along the optical axis O direction becomes larger.

  In the fifth embodiment, one shape memory alloy wire 32 is used as one shape memory alloy member. However, the present invention is not limited to this. For example, one shape memory alloy member is composed of a plurality of shape memory alloy wires 32-1 to 32-3 as shown in the second embodiment described with reference to FIGS. One shape memory alloy member 32A may be used, or one shape memory alloy member formed in a coil shape as shown in the third embodiment described with reference to FIG. 32B may be used.

  By using one shape memory alloy member 32A composed of a plurality of shape memory alloy wires 32-1 to 32-3, durability during lens driving can be improved. Further, by using one shape memory alloy member 32B formed in a coil shape, the lens displacement amount (stroke of the lens movable portion) of the lens driving device 10D can be greatly increased.

  In the fifth embodiment, the elastic member 20B (the upper leaf spring 26B, the upper plate spring 26B) is used to hold the lens movable portion (11, 18B) and apply a back tension to the lens movable portion (11, 18B). Although the lower leaf spring 28B) and the first and second urging shape memory alloy members 41 and 42 are provided, it is of course not limited thereto. For example, the elastic member 20B (the upper leaf spring 26B, the lower leaf spring 28B) is omitted, and the lens movable portion (11, 18B) is held only by the first and second urging shape memory alloy members 41, 42, You may make it provide a back tension with respect to a lens movable part (11, 18B).

  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, the guide means (elastic member; leaf spring) is not limited to the above-described embodiment, and various types may be used. Further, in the above-described embodiment, the lens holder includes two holder hook portions arranged so as to protrude in the radial direction from the cylindrical portion 182 at equal angular intervals of 180 ° with the optical axis O as the center. However, the number of holder / hook portions is not limited to 2, and may be generally N (N is an integer of 2 or more). In this case, the N holder hook portions are arranged so as to protrude in the radial direction from the cylindrical portion 182 at an equal angular interval of (360 ° / N) with the optical axis O as the center.

10, 10A, 10B, 10C Lens drive device 11 Lens barrel (lens assembly)
11a Male thread 12, 12A Housing (housing)
14, 14A Actuator base 142 Base portion 142a Support protrusion 146 First base protrusion 146a Electrode holding portion 146A First base protrusion (first sliding contact protrusion)
146Aa First sliding contact portion 146Ab First electrode holding portion 146Ac Support projection 147 Second base protruding portion 147A Second base protruding portion (second sliding contact protruding portion)
147Aa Second sliding contact portion 148 Third base protruding portion 148a Housing hook portion 148A Third base protruding portion (third sliding contact protruding portion)
148Aa Third sliding contact portion 148Ac Support protrusion 149 Fourth base protruding portion 149A Fourth base protruding portion (fourth sliding contact protruding portion)
149Aa Fourth sliding contact portion 149Ab Second electrode holding portion 16, 16A Outer upper cover 161 Right wall surface (first side surface)
162 left wall surface 163 front wall surface 164 rear wall surface 165 upper wall surface 165a circular opening 18, 18A lens holder 182 cylindrical portion 182a female screw 182b upper holder projection portion 184 holder / hook portion 184A projection portion (holding projection; holder / hook portion)
20, 20A Elastic member 26, 26A Upper leaf spring (front spring)
262 Inner peripheral end 262A Upper ring portion 262Aa Upper spring hole 264 Outer peripheral end 264A Upper end 264Aa Upper end hole 266 Upper arm 28, 28A Lower leaf spring (rear spring)
282 Inner peripheral side end 282A Lower ring part 282Aa Lower spring hole 284 Outer peripheral end part 284A Lower end part 284Aa Lower end hole 286 Lower arm part 30, 30A Inner upper cover 32 One linear Shape memory alloy wire 32A One shape memory alloy member 32-1, 32-2, 32-3 Shape memory alloy wire 32B One coil shape memory alloy member 34, 34A Electrode 342, 342A Terminal portion 342Aa Widened portion 344 Connection portion 36, 36A, 36B, 36C SMA assembly 38 Bias spring 382 Ring portion 384 Energizing spring portion O Optical axis of lens AFL Autofocus lens (movable lens)

Claims (11)

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 single shape memory alloy member that extends substantially around the outer periphery of the lens holder and is stretched between the lens holder and the housing;
The lens holder is arranged to project radially outward from the cylindrical portion at an equiangular interval of (360 ° / N) (N is an integer of 2 or more) with the optical axis as the center, and the one shape Including N holder hook portions for latching the memory alloy member,
A lens driving device.   2. The lens drive according to claim 1, wherein the moving unit further includes a pair of electrodes that are respectively attached to both ends of the one shape memory alloy member and energize the one shape memory alloy member. apparatus. The housing includes an actuator base disposed on a lower side of the lens holder;
The actuator base includes an electrode holding portion that holds the pair of electrodes.
The lens driving device according to claim 2. N is equal to 2,
The housing has a substantially bottomed rectangular tube shape,
The electrode holding portion is formed in a protruding portion protruding upward from the actuator base at a first corner of the four corners of the housing,
The housing has the one shape memory alloy member at a second corner of the four corners of the housing opposite to the first corner on a first diagonal passing through the optical axis at right angles. Including a housing hook for hooking,
Two holder hook portions are formed in the lens holder on a second diagonal that passes through the optical axis orthogonally and intersects the first diagonal.
The lens driving device according to claim 3. N is equal to 2,
The housing has a substantially bottomed rectangular tube shape,
The actuator base has four sliding contact protrusions that protrude upward at the four corners of the housing and are in sliding contact with the one shape memory alloy member,
The electrode holding portion is formed on a pair of sliding contact protrusions adjacent to each other on the first side surface side of the housing among the four sliding contact protrusions,
Two holder hook portions are formed on the lens holder on a straight line that is parallel to the first side surface of the housing and passes through the optical axis at right angles.
The lens driving device according to claim 3.   6. The lens driving device according to claim 1, wherein the one shape memory alloy member is constituted by one shape memory alloy wire formed in a linear shape.   The lens driving device according to claim 1, wherein the one shape memory alloy member includes a plurality of shape memory alloy wires each formed in a linear shape.   The lens driving device according to claim 7, wherein the plurality of shape memory alloy wires are wound.   The lens driving device according to any one of claims 1 to 5, wherein the one shape memory alloy member is configured by a single shape memory alloy member formed in a coil shape.   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 any one of claims 1 to 9.   11. The lens driving device according to claim 10, wherein the elastic member includes an upper leaf spring and a lower leaf spring provided respectively on an upper side and a lower side of the cylindrical portion of the lens holder in the optical axis direction.

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