KR20110097555A - Lens driving device, charging method and sma assembly - Google Patents

Abstract

Making it possible to easily adjust the attachment load applied to the shape memory alloy wire.
The lens driving device 10 includes a lens holder 18 including a cylindrical portion 182 holding the lens barrel 11 and a housing for supporting the lens holder 18 so as to be movable only in the optical axis O direction. 14 and 16, moving means for moving the lens holder 18 in the optical axis O direction, and guide means for guiding the lens holder 18 to be movable only in the optical axis O direction. The moving means comprises a linear shape memory alloy wire 28 spanning between the lens holder 18 and the housings 14 and 16. Both ends of the shape memory alloy wire 18 are inserted into a pair of pipe-shaped electrodes 30.

Description

LENS DRIVING DEVICE, CHARGING METHOD AND SMA ASSEMBLY}

The present invention relates to a lens drive device, and more particularly, to a lens drive device using a shape memory alloy wire in an actuator, a charging method of a shape memory alloy wire, and an SMA assembly used in the lens drive device.

Background Art [0002] A linear actuator using a shape memory alloy (SMA) is known as an autofocus actuator or a zoom actuator of a camera.

For example, WO2007 / 113478A1 (Patent Document 1) discloses a camera lens driving device for driving the movement of one camera lens supported by one support structure (housing) by one suspension system. The camera lens driving device disclosed in Patent Document 1 mounts a subassembly having an SMA wire connected to at least one mounting member mounted on a support structure. At least two SMA wires are held with tension between the camera lens element and the support structure (housing) at an acute angle, respectively, with respect to the tensioning optical axis with components along the optical axis. The two SMA wires are held at an angle when viewed along the optical axis. The subassembly has an attachment member to which the SMA wire is connected by caulking. The attachment member is electrically connected to the SMA wire. Thus, the attachment member functions as an electrode. The attachment member (electrode) is comprised from the elongate metal piece, and is electrically connected with the edge part of an SMA wire by caulking the tip part.

Moreover, Unexamined-Japanese-Patent No. 2007-292864 (patent document 2) discloses the lens drive apparatus which improved the transmission efficiency and aimed at compactness. The lens driving device disclosed in Patent Document 2 includes a fixed barrel (housing), a lens frame (lens holder) holding part or all of a lens group (lens barrel) constituting the optical system, and a lens frame (lens) for the fixed barrel. Guide means for freely supporting the holder in the optical axis direction, and pressing means for pressing the lens frame toward one of the optical axis directions. The lens drive device moves the lens frame to the other side against the pressing of the pressing means against the fixed barrel.

The lens drive 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 barrel and are heated by energization to reduce the length of the predetermined relaxation state. The shape memory alloy wire returns to the length of a relaxed state when cooled by the energization stop. The wire bearing member is attached to the lens frame, and the action part set between the both ends of the shape memory alloy wire is caught so that the convex part may be in the direction of the curved shape toward one side.

In the embodiment of the lens driving apparatus 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 is fixed to a fixing barrel (housing). The energization control part energizes both ends of an SMA wire through a pair of wire support members. Thus, the wire support member functions as an electrode. The wire support member (electrode) is comprised from the elongate metal piece similarly to the attachment member (electrode) of the said patent document 1.

Moreover, Japanese Patent Laid-Open No. 2007-78954 (Patent Document 3) discloses a lens tilt configured to move an imaging lens in an optical axis direction using a shape memory alloy. The lens tilt disclosed in Patent Document 3 uses a shape memory alloy formed in a band shape with an imaging lens (lens barrel) for forming an object light and a mirror frame (lens holder) for holding the imaging lens (lens barrel). The imaging lens is moved in a predetermined direction. A part of the shape memory alloy is disposed in the optical path of the imaging lens (lens barrel), and the mirror frame (lens holder) is moved by shrinking the shape memory alloy by energization. Patent document 3 also discloses that a pair of diaphragm type leaf springs are provided in the optical axis direction both ends of a mirror frame (lens holder) as an embodiment of lens tilting.

In the embodiment of the lens tilt disclosed in Patent Document 3, both ends of the shape memory alloy formed in the form of a band are squeezed and fixed by a pair of plate members to a columnar portion (housing) standing up from a fingerboard. The shape memory alloy is energized through the plate member. Thus, the plate member functions as an electrode.

Japanese Laid-Open Patent Publication No. 2009-19507 (Patent Document 4) discloses a drive module and a method of assembling which allow the variation in the assembly accuracy to be reduced while improving the production efficiency. The driving module disclosed in Patent Document 3 is hooked to an intermediate portion of a shape memory alloy (SMA) wire that is moved on a chassis (housing; support) so that a driven member (lens holder) is stretched in accordance with the amount of energization. The drive module has a pair of holding terminals, and the chassis (housing) has a positioning portion and a step portion. Each holding terminal has a wire holding part for holding the end of the SMA wire so as to be conductive, a positioning portion for the support, and a catch portion receiving a reaction force from the support toward the positioning portion. The positioning section hangs the positioning section of the holding terminal. The stepped part hangs the latched part of the holding terminal toward the position to be positioned. The holding terminal functions as an electrode because it is an energized portion. The holding terminal (electrode) consists of a key plate-shaped member, and the end of the SMA wire is caulked at the wire holding portion.

WO2007 / 113478A1 Japanese Patent Publication No. 2007-292864 Japanese Patent Publication No. 2007-78954 Japanese Patent Publication No. 2009-19507

The above-mentioned patent documents 1-4 have the problem as demonstrated below, respectively.

In the camera lens driving apparatus disclosed in Patent Document 1, an elongated metal piece is used as the attachment member (electrode) for the shape memory alloy wire. Therefore, it becomes very difficult to adjust the attachment load applied to the shape memory alloy wire.

The lens drive device disclosed in Patent Document 2 also uses an elongated metal piece as a pair of wire support members (electrodes) for an SMA wire. Therefore, it becomes very difficult to adjust the attachment load applied to SMA wire.

In the lens tilt disclosed in Patent Document 3, a pair of plate members is used as an electrode. Therefore, it becomes very difficult to adjust the attachment load applied to the strip | belt-shaped shape memory alloy.

In the drive module disclosed in Patent Document 4, a key plate member is used as a pair of holding terminals (electrodes) for SMA wires. Therefore, it becomes very difficult to adjust the attachment load applied to SMA wire.

In the lens driving apparatus, setting the attachment load applied to the shape memory alloy wire is a very important point from the viewpoint of shrinkage amount of the shape memory alloy member, displacement amount of the lens (stroke), durability, and the like.

Therefore, the subject of this invention is providing the lens drive apparatus which can easily adjust the attachment load applied to a shape memory alloy wire, the charging method of a shape memory alloy wire, and the SMA assembly used for a lens drive apparatus.

Other objects of the present invention will become clear as the description proceeds.

According to the first aspect of the present invention, the lens holder 18 including the cylindrical portion 182 holding the lens barrel 11 and the lens holder 18 are supported to be movable only in the optical axis O direction. A lens drive having a housing 12, a moving means for moving the lens holder 18 in the optical axis O direction, and a guide means for guiding the lens holder 18 so as to be movable only in the optical axis O direction. In the apparatus (10; 10A), the moving means comprises a linear shape memory alloy wire (28) between the lens holder (18) and the housing (12), and both ends of the shape memory alloy wire (18) A lens drive device is obtained, which is inserted into a pair of pipe-shaped electrodes 30.

In the lens driving device (10; 10A) according to the first aspect of the present invention, the lens holder (18) projects radially outward from the cylindrical portion (182), and the intermediate portion of the shape memory alloy wire (28). It is preferable to have the step | step protrusion 184 which hangs 28a. Each of the pair of pipe-shaped electrodes 30 is held in the housing 12 and extends in parallel with the optical axis O direction, and a stepping protrusion from the tip of the cylindrical portion 302 ( It is preferable that the tip cylindrical portion 304 bend toward 184. It is preferable that the pair of pipe-shaped electrodes 30 each have a caulking portion 302a which is electrically connected to both ends of the shape memory alloy wire 28 at the ends of the cylindrical portion 302, respectively. . The caulking portion 302aB preferably has an uneven inner circumferential surface 302aB 'that prevents the shape memory alloy wire 28 from being pulled out.

In the lens driving device 10A according to the first aspect of the present invention, it is preferable that a specific resin is injected into the pair of pipe-shaped electrodes 30 from the end of the cylindrical portion 302. The specific resin may be a conductive resin such as silver paste, for example, and may be an adhesion reinforcing resin to the shape memory alloy wire 28.

In addition, in the lens drive device 10; 10A according to the first aspect of the present invention, the guide means may include an elastic member 20 disposed between the lens holder 18 and the housing 12. In this case, the elastic member 20 supports the lens holder 18 so as to be displaceable only in the optical axis O direction with the lens holder 18 positioned in the radial direction. Even if the elastic member 20 is comprised, for example with the upper leaf spring 22 and the lower leaf spring 24 provided in the upper and lower sides of the cylindrical part 182 of the lens holder 18 in the optical axis O direction, respectively. do. The upper leaf spring 22 has, for example, an upper ring portion 222 attached to the upper end of the lens holder 18, four upper ends 224 attached to the housing 12, an upper ring portion and four upper ends. What is necessary is just to consist of four upper arm parts 226 which connect each. The lower leaf spring 24 connects the lower inner ring portion 242 attached to the lower end of the lens holder 18, the lower outer ring portion 244 attached to the housing 12, and connects the lower inner ring portion and the lower outer ring portion. What is necessary is just to consist of the several lower arm part 246.

According to the second aspect of the present invention, in the lens driving apparatus, the shape memory alloy wire 18 is provided as a method of charging both ends of the shape memory alloy wire 18 to the pair of pipe-shaped electrodes 30. A step of inserting a portion from the end of the pipe-shaped electrode 30L to the end of the other pipe-shaped electrode 30R in a state in which a part protrudes from the end of the other pipe-shaped electrode 30R, and the one pipe-shaped electrode ( Caulking one pipe-shaped electrode 30L and the shape memory alloy wire 28 to form a caulking portion 302a at the end of 30L), and protruding from the other end of the other pipe-shaped electrode 30R. A process of adjusting the attachment load applied to the shape memory alloy wire 28 by holding a part of the shape memory alloy wire 28 and moving the shape memory alloy wire 28 along the protruding direction, Subsequently, a charging method including a step of caulking the other pipe-shaped electrode 30R and the shape memory alloy wire 28 to form the caulking portion 302a at the other end of the other pipe-shaped electrode 30R is obtained. .

In the charging method according to the second aspect of the present invention, the caulking portion 302aB preferably has an uneven inner circumferential surface 302aB 'which prevents the shape memory alloy wire 28 from being pulled out. The process of cutting a part of shape memory alloy wire 28 which protrudes from the tail end of the other pipe-shaped electrode 30R may further be included. It is preferable to further include the process of inject | pouring a specific resin inside from the tail end of a pair of pipe-shaped electrode 30. FIG. The said specific resin should just be a conductive resin which consists of silver paste etc., for example, and should just be adhesion reinforcement resin with respect to the shape memory alloy wire 18.

According to the third aspect of the present invention, there is provided an SMA assembly 32 composed of a linear shape memory alloy wire 28 and a pair of electrodes attached to both ends of the shape memory alloy wire, wherein the pair of electrodes has a shape. An SMA assembly is obtained, which is composed of a pair of pipe-shaped electrodes 30 into which both ends of the memory alloy wire 28 are inserted.

In the SMA assembly 32 according to the third aspect of the present invention, the pair of pipe-shaped electrodes 30 have a pair of cylinder-shaped portions 302 extending in parallel with each other, and the pair of cylinder-shaped portions. It is preferable that it consists of a pair of tip cylindrical part 304 bent at an acute angle toward the side closer to each other from the tip.

In addition, the code | symbol in the said parentheses is attached in order to make understanding easy, It is a matter of course that it is only an example and is not limited to these.

In the present invention, the moving means for moving the lens holder in the optical axis direction includes a linear shape memory alloy wire sandwiched between the lens holder and the housing, and both ends of the shape memory alloy wire are inserted into a pair of pipe-shaped electrodes. The attachment load applied to the shape memory alloy wire can be easily adjusted.

BRIEF DESCRIPTION OF THE DRAWINGS The perspective view which looked at the external appearance of the lens drive apparatus which concerns on 1st Embodiment of this invention at an oblique front upward.
FIG. 2 is a perspective view, as viewed obliquely from above, omitting the lens barrel from the lens driving apparatus shown in FIG.
FIG. 3 is a perspective view of the lens drive device shown in FIG. 2, with the outer side cover omitted, and viewed obliquely from above.
4 is an exploded perspective view of the lens driving device illustrated in FIG. 2 as viewed obliquely from above.
FIG. 5 is a front view of the lens driving apparatus shown in FIG. 3.
6 is a perspective view showing the appearance of a pipe-shaped electrode used in the lens driving device shown in FIG. 1.
7 is a front view of the lens driving apparatus with the upper cover omitted in order to explain the flow of the charging step of charging both ends of the shape memory alloy wire to the pair of pipe-shaped electrodes.
FIG. 8A is a cross-sectional view showing a state before caulking a pipe-shaped electrode to a shape memory alloy wire, and FIG. 8 (B) is a cross-sectional view showing a state after caulking a pipe-shaped electrode to a shape memory alloy wire.
9 is a front view of the lens driving apparatus according to the second embodiment of the present invention with the lens barrel and the upper cover omitted.
Fig. 10 is a perspective view, viewed obliquely from the front, omitting the lens barrel and the outer cover from the lens driving apparatus according to the third embodiment of the present invention.
It is explanatory drawing which shows typically the state before caulking a pipe-shaped electrode to a shape memory alloy wire.
It is explanatory drawing which shows typically the state after caulking a pipe-shaped electrode to a shape memory alloy wire.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described with reference to drawings.

With reference to FIGS. 1-5, the lens drive apparatus 10 which concerns on 1st Embodiment of this invention is demonstrated. 1 is a perspective view of the lens driving apparatus 10 as viewed obliquely from above. FIG. 2 is a perspective view of the lens drive device 10 viewed obliquely from above in a state where the lens barrel 11 is omitted. FIG. 3 is a perspective view of the lens driving device 10 viewed obliquely from above in a state where the lens barrel 11 and the upper cover 16 are omitted. 4 is an exploded perspective view of the lens driving device 10 viewed obliquely from above in a state where the lens barrel 11 is omitted. 5 is a front view showing the lens driving apparatus 10 with the lens barrel 11 and the upper cover 16 omitted.

Here, as shown in Figs. 1 to 5, rectangular coordinate systems (X, Y, Z) are used. 1 to 5, in the Cartesian 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 The direction is the vertical direction (height direction). In the example shown in FIGS. 1-5, the up-down direction Z is the optical axis O direction of a lens. In addition, in this specification, a front direction is also called a 1st side and a rear direction is also called a 2nd side.

In the actual use situation, however, the optical axis O direction, that is, the Z axis direction is the front-rear direction. In other words, the upper direction of the Z axis is the forward direction, and the lower direction of the Z axis is the rear direction.

The illustrated lens drive device 10 passes through the optical axis O and has a surface symmetrical structure with respect to the (extended) plane defined by the front-rear direction X and the vertical direction Z. As shown in FIG.

The illustrated lens driving device 10 is provided in, for example, a mobile phone with an autofocusable camera. The lens driving apparatus 10 includes a lens barrel (lens assembly) 11 in which an autofocus lens AFL, which is a movable lens, is incorporated. 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 an approximately rectangular parallelepiped body (housing) 12 covering the 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 upper cover 16.

In addition, although not shown in figure, the imaging element arrange | positioned at the board | substrate is mounted in the center part of the actuator base 14. This imaging element picks up an image of an object formed by the movable lens AFL and converts it into an electrical signal. The imaging device is configured by, for example, a charge coupled device (CCD) type image sensor, a complementary metal oxide semiconductor (CMOS) type image sensor, or the like.

The lens driving device 10 includes a lens holder 18 holding the lens barrel 11. In other words, the lens barrel 11 is held and fixed in the lens holder 18. In detail, the lens holder 18 includes the cylindrical part 182 which has a substantially cylindrical shape. A female screw (not shown) is formed on the inner circumferential wall of the cylindrical portion 182 of the lens holder 18. On the other hand, the outer circumferential wall of the lens barrel 11 is formed with a male screw (not shown) that is screwed to the female screw. Therefore, in order to mount the lens barrel 11 to the lens holder 18, the lens barrel 11 is rotated about the optical axis O with respect to the lens holder 18, and the lens barrel 11 is screwed along the optical axis O direction. 11 is housed in the lens holder 18 and bonded to each other by an adhesive or the like.

The lens holder 18 is supported in the housing 12 so as to be movable only in the optical axis O direction as described later. The lens movable parts 11 and 18 are formed by the combination of the lens barrel 11 and the lens holder 18.

The outer circumferential wall of the cylindrical portion 182 of the lens holder 18 has a protrusion 184 protruding radially outward from the front of the front-back direction X. The protrusion 184 protrudes from the cylindrical portion 182 toward the lower end along the vertical direction Z. As shown in FIG. This protrusion 184 is for hooking the intermediate portion 28a of the shape memory alloy wire 28 formed in a linear shape to be described later. Therefore, the protrusion 184 is also referred to as a step protrusion.

The actuator base 14 includes a ring-shaped base portion 142, a pair of base front protrusions 144 projecting upward in the up-down direction Z at two edges in front of the base portion 142, and a base. It has a pair of base rear protrusion 146 which protrudes upwards in the up-down direction Z in the two edges of the back of the part 142. As shown in FIG. The pair of base front protrusions 144 each has a pair of base front protrusions 144a which protrude upwards. The pair of base rear protrusions 146 each have a pair of base rear protrusions 146a which protrude upwards. The pair of base front protrusions 144 each has a pair of engagement grooves 144b for engaging and holding a pair of pipe-shaped electrodes 32 described later. The pair of engaging grooves 144b extend in the vertical direction Z from the front surface of the pair of base front protrusions 144. The pair of base front protrusions 144 also has a pair of positioning recesses 144c for positioning and holding a pair of pipe-shaped electrodes 30, which will be described later.

The lens driving device 10 includes an upper leaf spring 22 and a lower leaf spring 24 provided respectively above and below the optical axis O direction of the cylindrical portion 182 of the lens holder 18. The upper leaf spring 22 and the lower leaf spring 24 are disposed between the lens holder 18 and the housing 12 so that they can be displaced in the optical axis O direction while the lens holder 18 is positioned in the radial direction. It functions as the elastic member 20 which supports it easily.

As described above, in the actual use situation, the upper direction in the Z axis direction (optical axis O direction) is the forward direction, and the lower direction in the Z axis direction (optical axis O direction) is the rear direction. Therefore, the upper leaf spring 22 is also referred to as the front spring, and the lower leaf spring 24 is also referred to as the rear spring.

The upper leaf spring 22 is disposed above the optical axis O direction in the lens holder 18, and the lower leaf spring 24 is disposed below the optical axis O direction in the lens holder 18.

The upper leaf spring 22 has an upper ring portion 222 attached to the upper end of the lens holder 18 and four upper ends 224 attached to the four corners of the housing 12 as described below. Four upper arm portions 226 are provided between the upper ring portion 222 and the four upper end portions 224. That is, the four upper arm portions 226 connect the upper ring portion 222 and the four upper end portions 224.

The upper ring portion 222 of the upper leaf spring 22 is fixed to the cylindrical portion 182 of the lens holder 18. In detail, the lens holder 18 has four upper holder protrusions 186 projecting radially outward from the upper end of the cylindrical portion 182. The four upper holder protrusions 186 each have four upper holder protrusions 186a which protrude upwards. The upper ring portion 222 of the upper leaf spring 22 has four upper spring holes 222a into which these four upper holder protrusions 186a are respectively inserted.

On the other hand, the four upper end portions 224 of the upper leaf springs 22 are fixed to the pair of base front protrusions 144 and the pair of base rear protrusions 146 of the actuator base 14. In detail, the four upper ends 224 of the upper leaf springs 22 each have a pair of base front protrusions 144a and a pair of base rear protrusions 146 formed on the pair of base front protrusions 144. Has a four upper end holes 224a into which a pair of base rear protrusions 146a are formed.

On the other hand, the lower leaf spring 24 has a lower inner ring portion 242 attached to the lower end of the lens holder 18 and a lower outer ring portion 244 attached to the actuator base 14. Four lower arm portions 246 are provided between the lower inner ring portion 242 and the lower outer ring portion 244. That is, the four lower arm portions 246 connect the lower inner ring portion 242 and the lower outer ring portion 244.

In addition, although the number of the lower arm parts 246 is four in the example shown, what is necessary is just a plurality.

The elastic member 20 including the upper leaf spring 22 and the lower leaf spring 24 functions as a guide means for guiding the lens holder 18 to be movable only in the optical axis O direction. Each of the upper leaf spring 22 and the lower leaf spring 24 is made of beryllium copper, phosphor bronze, and the like.

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

The lens drive device 10 includes a shape memory alloy wire 28 formed in a linear shape disposed near the outer wall of the cylindrical portion 182 of the lens holder 18, and both ends of the shape memory alloy wire 28, respectively. A pair of electrically connected pipe-shaped electrodes 30 are provided. The combination of the shape memory alloy (SMA) wire 28 and the pair of pipe-shaped electrodes 30 is referred to as the shape memory alloy (SMA) assembly 32. The SMA assembly 32 is held by the pair of base front protrusions 144 of the actuator base 14 as described later.

6 is a perspective view showing the appearance of the pipe-shaped electrode 30.

As shown in FIG. 4, the pair of pipe-shaped electrodes 30 have a symmetrical shape. The pair of pipe-shaped electrodes 30 extend substantially in the vertical direction Z. As shown in FIG. The pair of pipe-shaped electrodes 30 are a pair of cylinder-shaped portions 302 extending in parallel with each other, and a pair bent at an acute angle toward a side proximate to each other from the front end (top) of the cylinder-shaped portion 302. A tip cylindrical portion 304 is formed.

In the illustrated example, the diameter of the wire rod of the shape memory alloy (SMA) wire 28 is 50 µm, and the inner diameter of the pipe-shaped electrode 30 is 0.3 mm. Both ends of the shape memory alloy wire 28 are inserted into a pair of pipe-shaped electrodes 30. Both ends of the shape memory alloy wire 28 are inserted not only in the pair of tip cylindrical portions 304 of the pair of pipe-shaped electrodes 30, but also in the pair of main cylindrical portions 302. That is, the pair of pipe-shaped electrodes 30 serve as guides of the shape memory alloy wire 28. Thereby, the attachment load applied to the shape memory alloy wire 28 can be adjusted easily as mentioned later.

In other words, as shown in Figs. 3 and 4, each of the pair of pipe-shaped electrodes 30 is held in the housing 12 and extends in parallel with the optical axis O direction, and The tip cylindrical portion 304 is bent from the tip (upper end) of the cylindrical portion 302 toward the step protrusion 184 of the lens holder 18.

With reference to FIG. 3 and FIG. 5, the attachment state to the pair of base front protrusion 144 of the actuator base 14 of the SMA assembly 32 is demonstrated.

The pair of cylindrical portions 302 of the pair of pipe-shaped electrodes 30 are engaged with and held by the pair of engaging grooves 144b formed in the pair of base front protrusions 144. The pair of tip cylindrical portions 304 of the pair of pipe-shaped electrodes 30 are positioned and held in the pair of positioning recesses 144c formed in the pair of base front protrusions 144. Thereby, the shape memory alloy wire 28 is extended in the plane prescribed | regulated by the up-down direction Z and the left-right direction Y. FIG. Each pipe-shaped electrode 30 is electrically connected to an end of the shape memory alloy wire 28 by caulking the lower end of the cylindrical portion 302 as described later. That is, the pair of pipe-shaped electrodes 30 each have a caulking portion 302a which is electrically connected to both ends of the shape memory alloy wire 28 at the end of the cylindrical portion 302.

In this way, the SMA assembly 32 is attached to the pair of base front protrusions 144 of the actuator base 14. In addition, the intermediate portion 28a of the shape memory alloy wire 28 is engaged with the protrusion (step projection) 184 of the lens holder 18. That is, the shape memory alloy wire 28 spans 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, the "shape memory alloy" is a metal having a property in which a given strain distortion becomes zero in a specific temperature range and is restored to its original shape. The shape memory alloy is made of, for example, a TiNi alloy.

In addition, the shape memory alloy wire 28 shown in the figure is contracted to a pre-stored contraction length when self-heating by energization, and returns to a predetermined original length (length of a relaxed state) by natural cooling when the energization is stopped. Is the wire.

The elastic member 20 acts to press the lens holder 18 downward along the optical axis O direction. On the other hand, the shape memory alloy wire 28 is contracted when it is energized from the drive circuit (not shown) via the pair of pipe-shaped electrodes 30. As a result, the lens holder 18 moves upward along the optical axis O direction against the pressing force in the downward direction of the elastic member 20.

On the other hand, when power supply to the shape memory alloy wire 28 is stopped, the shape memory alloy wire 28 is naturally cooled. As a result, the shape memory alloy wire 28 is extended by the downward 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 28 expands and contracts in the optical axis O direction due to the temperature change caused by energization / non-energization, and functions as a moving means for moving the lens holder 18 in the optical axis O direction.

The combination of the elastic member 20 and the SMA assembly 32 supports the lens movable parts 11 and 18 so as to be movable in the optical axis O direction, while driving the lens movable parts 11 and 18. Function as).

The lens drive units 20 and 32 and the lens movable units 11 and 18 are provided side by side with respect to the optical axis O as shown in FIG. 5. Therefore, the lens drive device 10 can be reduced in size.

Next, with reference to FIGS. 7 and 8, a method of charging both ends of the shape memory alloy wire 28 to the pair of pipe-shaped electrodes 30 will be described. 7 is a front view of the lens driving apparatus 10 with the upper cover 16 omitted in order to explain the flow of the charging process of the shape memory alloy wire 28. FIG. 8A is a cross-sectional view showing a state before caulking the pipe-shaped electrode 30 to the shape memory alloy wire 28, and FIG. 8 (B) shows the pipe-shaped electrode 30 to the shape memory alloy wire 28. FIG. It is sectional drawing which shows the state after caulking to ().

In FIG. 7, in order to distinguish a pair of pipe-shaped electrodes 30, 30L reference | symbol is attached | subjected to the pipe-shaped electrode on the left which is one pipe-shaped electrode, and 30R is attached to the pipe-shaped electrode on the right which is the other pipe-shaped electrode. The reference sign is attached.

As shown in Fig. 7A, first, the shape-memory alloy wire 28 is connected to the pipe-shaped electrode on the right side from the lower end (the end) of the pair of pipe-shaped electrodes 30 on the left side of the pipe-shaped electrode 30L. It inserts into a pair of pipe-shaped electrode 30, guiding to the lower end (lower end) of 30R. At this time, the intermediate portion 28a of the shape memory alloy wire 28 is caught by the step protrusion 184 of the lens holder 18. At this time, as shown in Fig. 7A, a part of the shape memory alloy wire 28 is exposed (projected) from the lower end (end) of the pipe-shaped electrode 30R on the right side.

Next, at the lower end (lower end) of the cylindrical portion 302 of the left pipe-shaped electrode 30L, which is the position indicated by arrow A in Fig. 7A, the left pipe-shaped electrode 30L and the shape memory alloy are formed. The wire 28 is caulked as shown in FIG.

Subsequently, as shown by arrow B in FIG. 7A, the shape memory alloy wire 28 exposed (protrudes) from the lower end (end) of the cylindrical portion 302 of the pipe-shaped electrode 30R on the right side. A part of) is gripped and the shape memory alloy wire 28 is moved up and down along the vertical direction Z (the protruding direction), so that the shape memory alloy wire 28 in the step projection 18 is intermediate. The attachment load applied to the part 28a is adjusted.

After adjustment of the attachment load, the shape of the pipe-shaped electrode 30R on the right side is formed at the lower end (the end) of the cylindrical portion 302 of the pipe-shaped electrode 30R on the right side, which is the position shown by arrow C in FIG. 7 (B). The memory alloy wire 28 is caulked as shown in FIG.

Thereafter, a part of the shape memory alloy wire 28 exposed (protrudes) from the lower end (end) of the cylindrical portion 302 of the pipe-shaped electrode 30R on the right side is cut.

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

As described with reference to FIGS. 7A and 7B, the attachment load applied to the shape memory alloy wire 28 can be easily adjusted.

As shown in Figs. 8A and 8B, the electrical connection work (caulking step) of the shape memory alloy wire 28 and the pair of pipe-shaped electrodes 30 can be easily performed. That is, the caulking point (electrical connection point) can be freely selected and caulked by using the pipe-shaped electrode 30 according to the embodiment of the present invention, rather than folding and caulking an electrode made of a conventional metal piece. .

In addition, since the effective length of the shape memory alloy wire 28 (that is, the wire length between the electrical connection points (caulking points)) can be lengthened, increasing the lens displacement amount (stroke amount of the lens movable parts 11 and 18) is increased. It becomes possible. The reason for this is as follows. In the lens drive device 10 according to the present embodiment, the shape memory alloy wire 28 can be extended to the bottom surface side of the actuator base 14 along the pair of pipe-shaped electrodes 30. Therefore, the pair of pipe-shaped electrodes 30 and the shape memory alloy wires 28 can be caulked at the lower ends (end ends) of the pair of pipe-shaped electrodes 30. For this reason, the shrinkage amount of the shape memory alloy wire 28 can be increased. As a result, the lens displacement amount can be increased.

Next, with reference to FIG. 9, the lens drive apparatus 10A which concerns on 2nd Embodiment of this invention is demonstrated. FIG. 9 is a front view showing the lens driving apparatus 10A with the lens barrel 11 and the upper cover 16 omitted.

The lens driving device 10A shown in FIG. 1 to 5 is a lens driving device shown in FIGS. 1 to 5 except that a specific resin as described later is injected into the pair of pipe-shaped electrodes 30. It operates with the configuration similar to (10). The same reference numerals are given to the same components as those of the lens driving apparatus 10, and their description is omitted, and only the differences will be described below.

In the illustrated lens drive device 10A, as shown by arrow D in FIG. 9, a conductive resin is formed as a specific resin therein from the lower end (not end) of the cylindrical portion 302 of the pair of pipe-shaped electrodes 30. Is injected (coated). As the conductive resin, for example, silver paste can be used. This makes it possible to securely establish the conduction between the pair of pipe-shaped electrodes 30 and the shape memory alloy wire 28.

In addition, in the lens drive device 10A shown in FIG. 9, although conductive resin is used as specific resin, you may use adhesion reinforcement resin with respect to the shape memory alloy wire 28 instead of conductive resin. In this case, the shape memory alloy wire 28 can be reliably attached to the pair of pipe-shaped electrodes 30.

In any case, in the lens driving apparatus according to the present invention, it is possible to inject (co) the specific resin after the completion of the product.

Next, with reference to FIGS. 10-12, the lens drive apparatus 10B which concerns on 3rd Embodiment of this invention is demonstrated. Fig. 10 is a perspective view, viewed obliquely from the front, and omitting the lens barrel and the outer cover from the lens driving apparatus according to the third embodiment of the present invention, and Fig. 11 shows a state before caulking the pipe-shaped electrode to the shape memory alloy wire. Is an explanatory diagram schematically showing FIG. 12 is an explanatory diagram schematically showing a state after caulking a pipe-shaped electrode to a shape memory alloy wire.

The lens driving apparatus 10B shown in FIG. 1 is different from the aspect of the caulking portion 302aB formed at the trailing end of the cylindrical portion 302 of the pair of pipe-shaped electrodes 30 as described later. It operates with the same structure as the lens drive apparatus 10 shown to FIG. The same reference numerals are given to the same components as those of the lens driving apparatus 10, and their description is omitted, and only the differences will be described below.

In the illustrated lens driving device 10B, as shown in FIGS. 10 to 12, the caulking portion 302aB formed at the end of the cylindrical portion 302 of the pair of pipe-shaped electrodes 30 has a shape memory alloy wire. It has an uneven inner peripheral surface 302aB 'which prevents the omission of (28). Moreover, the uneven part corresponding to the uneven | corrugated inner peripheral surface 302aB 'is formed also in the outer peripheral surface side of the caulking part 302aB.

This uneven inner peripheral surface 302aB 'is formed so that a plurality of concave portions and convex portions may be alternately repeated along the longitudinal direction of the cylindrical portion 302.

As shown in FIGS. 11 and 12, the caulking portion 302aB uses a caulking jig T having a concave-convex surface on the pressing surface side that abuts against the cylindrical portion 302 to form the main cylindrical portion 302 and the shape memory. It is formed by caulking the alloy wire 28.

In addition, although the caulking jig T shown in FIG. 11 and FIG. 12 has an uneven surface on both pushing surfaces which contact the cylindrical part 302, using the caulking jig T which has an uneven surface only in the pushing surface of one side is used. It does not matter at all.

As a result, the concave-convex inner circumferential surface 302aB 'of the caulking portion 302aB and the shape-memory alloy wire 28 are engaged with the concave-convex shape, so that the shape-memory alloy wire 28 is formed in the cylindrical portion of the pipe electrode 30 ( 302 can be prevented from being removed, and since the junction area and the number of contacts between the uneven inner circumferential surface 302aB 'and the outer circumferential surface of the shape memory alloy wire 28 increase, the shape memory alloy wire 28 and the pipe-shaped electrode 30 are increased. The resistance nonuniformity between) can be suppressed.

As mentioned above, although this invention was shown and demonstrated especially with reference to the embodiment, this invention is not limited to these embodiment. It is 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) is not limited to the above-mentioned embodiment, You may use various things.

10, 10A... Lens driving device 11. Lens Barrel (Lens Assembly)
12... Housing 14. Actuator Base
142... Base portion 144... Base forward protrusion
144a.. Base anterior projection 144b... Home
144c.. Positioning recess 146... Base rear protrusion
146a... Base rear projection 16... Upper cover
18... Lens holder 182... Tubular part
184... Protrusion (step projection) 186... Upper holder protrusion
186a... Upper holder protrusion 20... Elastic member
22... Upper leaf spring 222... Upper ring
222a... Upper spring hole 224... Upper end
224a.. Upper end hole 226... Upper arm
24 ... Lower leaf spring 242... Lower inner ring
244... Lower outer ring portion 246... Lower arm
28 ... Linear shape memory alloy wire 28a... Middle section
30... Pipe-shaped electrode 30L... Pipe-shaped electrode on the left
30R... Pipe-shaped electrode 302 on the right side; Cylinder Shape
302a, 302aB... Caulking unit 302aB '... Uneven inner circumference
304... Tip cylindrical portion 32... SMA assembly
O… Optical axis of lens AFL... Auto focus lens
T… Caulking jig

Claims (22)

A lens holder including a cylindrical portion for holding a lens barrel, a housing for supporting the lens holder so as to be movable only in the optical axis direction, moving means for moving the lens holder in the optical axis direction, and the lens holder in the optical axis A lens driving apparatus comprising a guide means for guiding to be movable only in a direction,
And said moving means comprises a linear shape memory alloy wire spanning between said lens holder and said housing, and both ends of said shape memory alloy wire are inserted into a pair of pipe-shaped electrodes. The lens drive device according to claim 1, wherein the lens holder protrudes radially outward from the tubular portion, and has a step protrusion for hanging an intermediate portion of the shape memory alloy wire. 3. The cylindrical tube portion according to claim 2, wherein each of the pair of pipe-shaped electrodes is held in the housing and extends in parallel with the optical axis direction, and from the tip of the cylindrical portion to the tip cylindrical portion bent toward the step projection. It is comprised, The lens drive apparatus characterized by the above-mentioned. 4. The lens driving apparatus according to claim 3, wherein the pair of pipe-shaped electrodes each have a caulking portion electrically connected to both ends of the shape memory alloy wire at the ends of the cylindrical portion. The lens driving apparatus according to claim 4, wherein the caulking portion has an uneven inner circumferential surface for preventing the shape memory alloy wire from being pulled out. The lens drive device according to claim 4 or 5, wherein a specific resin is injected into the pair of pipe-shaped electrodes from the end of the cylindrical portion. The lens drive device according to claim 6, wherein the specific resin is a conductive resin. 8. A lens driving apparatus according to claim 7, wherein said conductive resin is made of silver paste. 7. The lens drive device according to claim 6, wherein the specific resin is adhesion reinforcement resin to the shape memory alloy wire. 10. The method according to any one of claims 1 to 9, wherein the guide means includes an elastic member disposed between the lens holder and the housing, wherein the elastic member is positioned in the radially positioned state of the lens holder. A lens drive device, characterized in that the support is displaceable only in the optical axis direction. The lens drive according to any one of claims 1 to 10, wherein the elastic member is composed of an upper leaf spring and a lower leaf spring respectively provided on the upper side and the lower side in the optical axis direction of the cylindrical portion of the lens holder. Device. 12. The apparatus of claim 11, wherein the upper leaf spring comprises: an upper ring portion attached to an upper end of the lens holder; four upper ends attached to the housing; and four upper sides connecting the upper ring portion and the four upper ends, respectively. A lens driving device having a dark portion. The lower leaf spring of claim 11 or 12, wherein the lower leaf spring connects the lower inner ring portion attached to the lower end of the lens holder, the lower outer ring portion attached to the housing, and the lower inner ring portion and the lower outer ring portion. A lens driving apparatus comprising a plurality of lower arm portions. The lens driving apparatus according to any one of claims 1 to 3, wherein both ends of the shape memory alloy wire are inserted into the pair of pipe-shaped electrodes.
A step of inserting the shape memory alloy wire in a state in which a part protrudes from the end of the other pipe-shaped electrode from the end of the one pipe-shaped electrode to the end of the other pipe-shaped electrode;
A step of caulking the one pipe-shaped electrode and the shape memory alloy wire to form a caulking portion at the end of the one pipe-shaped electrode;
A part of the shape memory alloy wire protruding from the other end of the other pipe-shaped electrode is sandwiched and the attachment load applied to the shape memory alloy wire is adjusted by moving the shape memory alloy wire along the protruding direction. Process to do,
And a step of caulking the one pipe-shaped electrode and the shape memory alloy wire to form a caulking portion at the trailing end of the other pipe-shaped electrode after the load adjustment. The charging method according to claim 14, wherein the caulking portions each have an uneven inner circumferential surface for preventing the shape memory alloy wire from being pulled out. The charging method according to claim 14 or 15, further comprising a step of cutting a part of the shape memory alloy wire protruding from the other end of the other pipe-shaped electrode. 17. The charging method according to claim 16, further comprising a step of injecting a specific resin into the interior from the ends of the pair of pipe-shaped electrodes. 18. The charging method according to claim 17, wherein the specific resin is a conductive resin. 19. The charging method according to claim 18, wherein the conductive resin is made of silver paste. 18. The charging method according to claim 17, wherein the specific resin is adhesion reinforcement resin to the shape memory alloy wire. An SMA assembly comprising a linear shape memory alloy wire and a pair of electrodes attached to both ends of the shape memory alloy wire,
And said pair of electrodes comprises a pair of pipe-shaped electrodes into which both ends of said shape memory alloy wire are inserted. 22. A pair of tip cylinders according to claim 21, wherein the pair of pipe-shaped electrodes extends in parallel to each other, and a pair of tip cylinders bent at an acute angle toward a side proximate to each other from a tip of the pair of cylindrical shapes. SMA assembly, characterized in that consisting of the shape.

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