JP4862703B2 - DRIVE DEVICE, DRIVE MECHANISM, AND IMAGING DEVICE - Google Patents

Description

  The present invention relates to a driving device, a driving mechanism, and an imaging device using the driving device for driving a lens unit constituting an imaging optical system such as a camera-equipped mobile phone for zooming and focusing.

  In recent years, image quality has been improved, for example, the number of pixels of an image sensor mounted on a camera-equipped mobile phone or the like has increased dramatically. In accordance with this, there is a demand for higher performance of the lens unit constituting the imaging optical system. Specifically, an optical zoom is required instead of a single focus type for an autofocus type and a zoom function instead of or in addition to a digital zoom. Here, a lens driving mechanism for moving the lens in the optical axis direction is required for both autofocus and optical zoom.

  Conventionally, a moving coil type is widely used as such a lens driving mechanism. This is achieved by attaching a pair of coils and magnets to a ball frame for fixing the lens and a stationary frame body for supporting the ball frame, and using a magnetic repulsive force that depends on the amount of current applied to the coil. The frame is driven in the optical axis direction. However, in this moving coil system, it is indispensable to use coils and magnets that are difficult to reduce in size, and this does not match the recent trend of reduction in size and weight. Further, since it is necessary to mount a heavy coil on the ball frame, there is a disadvantage that the ball frame has a large moment of inertia at the time of applying an impact and is inferior in impact resistance.

  As an alternative lens driving mechanism, one using a shape memory alloy (hereinafter sometimes referred to as SMA) actuator is known. This is to generate a contraction force by energizing and heating the SMA and using the contraction force as a lens driving force. Generally, it is easy to reduce the size and weight, and a relatively large force can be obtained. There is an advantage.

As a lens driving mechanism to which the SMA actuator is applied, for example, structures disclosed in Patent Documents 1 to 4 are known. Patent Document 1 discloses that an SMA spring and a bias spring are antagonistically arranged with a moving lens interposed therebetween. Patent Document 2 discloses a configuration in which an SMA wire is spirally wound around an outer periphery of a cam tube that guides a lens in the optical axis direction, and the cam tube is rotated by a contraction force of the SMA wire. Patent Document 3 discloses a configuration in which an SMA wire is bridged between a ball frame and a fixed portion, and the ball frame is moved by the contraction force of the SMA wire. Furthermore, Patent Document 4 discloses a lens driving mechanism including a configuration in which the contraction force of the SMA wire is expanded by a gear mechanism.
JP-A-9-127398 JP-A-2005-195998 JP 2002-130114 A Japanese Patent Application Laid-Open No. 2005-156892

  In general, the amount of contraction displacement obtained by energizing and heating SMA is only about a few percent of its total length. In consideration of durability, it is necessary to drive the SMA to contract within a displacement range of about 3% at most. For this reason, in the method in which the lens (ball frame) is directly driven by the SMA actuator as in the configurations of Patent Documents 1 to 3, the amount of movement of the lens is relatively small, and high-performance autofocus and optical zoom Therefore, there is a problem that a necessary lens movement amount cannot be obtained. Moreover, although the amount of displacement can be obtained by using the configuration of Patent Document 4, the mounting of the gear mechanism becomes an obstacle to reducing the size and weight.

  The present invention has been made in view of the above circumstances, and in a drive device to which an SMA actuator is applied, a drive device, a drive mechanism, and a drive device capable of obtaining a large amount of displacement while achieving a reduction in size and weight. An object of the present invention is to provide an image pickup apparatus.

A driving apparatus according to one aspect of the present invention is a driving apparatus for driving a driven object, and a displacement output unit that is movable in a predetermined first axis direction, and a second axis that is orthogonal to the first axis. A displacement input unit that receives an input of a moving force in a direction and moves the displacement output unit in the first axial direction, and a driving member that is engaged with the driven object in the displacement output unit, and at least the displacement A linear shape memory alloy actuator that is disposed in contact with the drive member at the input portion and applies the moving force to the displacement input portion; and the drive member has a hollow portion that can contain the driven object. It comprises four arms linked in a quadrangular shape and a bent portion so as to be provided, and the two vertex portions facing each other of the square are the displacement input portions, and the other two vertex portions facing each other are The displacement output unit; In addition, the bent portion is provided in the vicinity of the displacement input portion and the displacement output portion of the arm, so that the displacement input portion and the displacement output portion are arranged at positions shifted in the first axial direction. In addition, the displacement output unit is moved in the first axis direction when the displacement input unit receives an input of the moving force in the second axis direction (Claim 1).

In the above configuration, two drive members are used as a pair, and are combined such that the respective first axial directions are on the same axis line, and the displacement input portion is coupled, and the displacement in one drive member The output portion is fixed to a predetermined base member to be a fixed portion, and the displacement output portion of the other driving member is engaged with the driven object, so that the shape memory alloy actuator causes the first input from the displacement input portion. When an input of a biaxial movement force is received, the driven object engaged with the displacement output portion of the other drive member is moved to the first shaft with respect to the displacement output portion of the one drive member fixed. It is desirable to displace in the direction (Claim 2).

A driving apparatus according to another aspect of the present invention is a driving apparatus for driving a driven object, and a displacement output unit that is movable in a predetermined first axis direction and orthogonal to the first axis. A displacement input unit that receives an input of a moving force in the second axial direction and moves the displacement output unit in the first axial direction, and a driving member that is engaged with the driven object in the displacement output unit; A linear shape memory alloy actuator disposed at least in contact with the drive member at the displacement input section and applying the moving force to the displacement input section, and the drive member can include the driven object It comprises four arms linked in a square shape so as to have a hollow portion, a first drive piece comprising a bent portion, and a second drive piece having a similar square link. The first driving piece is the square Two vertex portions facing each other are used as the displacement input unit, and the other two vertex portions facing each other are used as the displacement output unit, and the second driving piece includes The apex portion serves as the displacement input portion, and the other two apex portions facing each other serve as a fixed portion that is fixed to a predetermined base member that does not move, both of which are displacement inputs of the first driving piece. And the displacement input portion of the second drive piece are coupled to each other, and the bent portion is provided in the vicinity of the displacement input portion and the displacement output portion of the arm, whereby the first drive The displacement output portion of the piece and the fixing portion of the second drive piece are arranged back and forth in the first axial direction (Claim 3).

  According to this configuration, the displacement in the second axis direction (first stage displacement) perpendicular to the first axis generated by the operation of the shape memory alloy actuator is given to the displacement input portion of the drive member, and the first In response to the stage displacement, the displacement output portion of the driving member performs displacement in the first axis direction (second stage displacement). Then, the driven object can be moved in the first axial direction by the second-stage displacement. That is, the displacement of the shape memory alloy actuator itself is not given to the driven object as it is, but the displacement is given to the driven object after changing the displacement direction via the driving member. For this reason, the shape memory alloy actuator used as a drive source can be arrange | positioned around a to-be-driven object, and size reduction of a 1st axial direction can be achieved. Further, by selecting the displacement force transmission system of the drive member that receives the first-stage displacement and outputs the second-stage displacement as the displacement expansion system, a displacement larger than the actual displacement of the shape memory alloy actuator is received. It becomes possible to give to a driving thing.

According to this configuration, the moving force is transmitted from the displacement input unit to the displacement output unit via the arm, and the bent portion functions as a node. Accordingly, when a movement force in the second axis direction is applied to the displacement input unit, the movement force can be converted into a movement force in the first axis direction and output from the displacement output unit. That is, the drive member can be configured with an extremely small number of parts and without using expensive parts.

In addition, according to the configuration of the first aspect, the movement force in the second axial direction is applied from the shape memory alloy actuator to the displacement input portions located at the two opposite vertex portions of the quadrangle, and the displacement caused thereby causes the arm to move. To the displacement output unit located at the other two vertexes. Then, the driven object engaged with the displacement output unit is moved in the first axial direction. That is, the displacement is transmitted without any intervention through the sliding part and the gear meshing part, so that the occurrence of backlash can be avoided and the backlash does not occur, so the driven object can be driven smoothly and with good output efficiency. It can be performed. In addition, by adopting a square link, a displacement larger than the displacement given to the displacement input unit can be easily output from the displacement output unit. Further, since a driving force is generated at the center of the first axis, it is possible to drive a driven object that is excellent in straightness.

Furthermore, according to the structure of Claim 2 or 3, generation | occurrence | production of a backlash and a backlash can be suppressed similarly to the above, and a drive with sufficient output efficiency can be performed. Furthermore, since the first drive piece and the second drive piece having the quadrangular link structure are coupled to each other, the second drive piece has a fixed portion. The driving member substantially includes a pantograph mechanism. Therefore, the displacement amount of the displacement output portion of the first drive piece can be made larger than the actual displacement amount of the shape memory alloy actuator. Furthermore, the pantograph mechanism can also function as a cushion body for a driven object, and a drive device having excellent impact resistance can be configured.

In the above structure, before Symbol shape memory alloy actuator, in a plane including the displacement input portion provided on the two apex portion facing each other of the square, it is suspended so as to surround the links of the rectangle, these in contact with the driving member only at the displacement input portion is desired (claim 4).

  According to this configuration, since the portion where the linear shape memory alloy actuator and the drive member rub against each other is limited to the displacement input portion, the drive force generated by the shape memory alloy actuator can be more efficiently applied to the drive member. Can do.

In these configurations, the displacement input portion is provided with a laying portion capable of guiding a wire, and the shape memory alloy actuator is formed of a single linear body having electrodes for current heating at both ends, and the displacement It is desirable that it is bridged over the erection part of the input part (claim 5 ).

  According to this configuration, it is possible to receive the deformation force due to energization heating of the shape memory alloy actuator made of a single linear body at the erection portion, and apply this to the displacement input portion. Therefore, a relatively large displacement generated by one shape memory alloy actuator can be input to the displacement input unit without loss.

In this case, a tension guide for constructing the shape memory alloy actuator along the quadrangular shape of the drive member is provided at a position on one side of the displacement output unit, and the shape memory alloy actuator includes the displacement output unit. It is desirable that the bridge is bridged so as to include a route that returns to the base point side via the construction part of the displacement input part and the tension guide, with the position on the other side of the base point as the base point (Claim 6 ).

  According to this configuration, the shape memory alloy actuator is installed in a quadrangular shape using two installation parts and one tension guide. Since the shape memory alloy actuator erected in this way expands and contracts by the same amount of displacement, rubbing or the like does not occur at the tension guide portion. Similarly, rubbing of the shape memory alloy actuator does not occur in the construction portion. Therefore, the loss of power due to rubbing can be minimized, and damage to the shape memory alloy actuator due to friction can be prevented.

In this configuration, the shape memory alloy actuator, by being folded or lap winding, it is possible to make to bridge the multiplexing respect installing portion and the tension guide of the displacement input portion (claim 7). According to this configuration, a large amount of force can be applied to the drive member by multiple spanning of the shape memory alloy actuator.

The displacement input part is provided with a erection part capable of guiding a wire, and the shape memory alloy actuator is composed of two linear bodies each having electrodes for current heating at both ends, and the shape memory alloy Each of the actuators may be constructed so as to be in contact with the construction part of the displacement input part (claim 8 ).

  According to this configuration, the shape memory alloy actuator is configured by two linear bodies that are relatively short as compared with the case where one linear body is bridged. Therefore, the current value when the same voltage is applied is increased, and the displacement response can be improved.

It is desirable that a plurality of the drive members described in claim 2 or 3 are stacked in the first axial direction (claim 9 ). According to this configuration, the amount of displacement of the driven object can be increased by the amount of accumulated driving members.

Furthermore, a driving apparatus according to another aspect of the present invention is a driving apparatus for driving a driven object, and a displacement output unit movable in a predetermined first axis direction, and orthogonal to the first axis. A displacement input unit that receives the input of the moving force in the second axial direction and moves the displacement output unit in the first axial direction, and a driving member that is engaged with the driven object in the displacement output unit; A linear shape memory alloy actuator disposed at least in contact with the drive member at the displacement input portion and applying the moving force to the displacement input portion, and the drive member is capable of inserting the driven object. It has an annular shape, and its axial cross-section has a square shape, and the square-shaped bent portion has a shape positioned at the outermost part in the radial direction, and the square-shaped bent portion is connected to the displacement input portion. And the peripheral portion of the cross section is a displacement output portion. Is characterized in that is (0 Claim 1).

  According to this structure, when a moving force is applied to the rectangular bent portion of the annular driving member corresponding to one segment of the bellows member, the driving member expands the rectangular cross section. Transforms into As a result, the peripheral portion of the rectangular cross section moves in the first axial direction, so that the driven object can be moved in the first axial direction. In such a configuration, the shape memory alloy actuator can be mounted on the drive member, and the size can be further reduced.

A driving apparatus according to another aspect of the present invention is a driving apparatus for driving a driven object, and a displacement output unit that is movable in a predetermined first axis direction and orthogonal to the first axis. A displacement input unit that receives an input of a moving force in the second axial direction and moves the displacement output unit in the first axial direction, and a driving member that is engaged with the driven object in the displacement output unit; A linear shape memory alloy actuator disposed at least in contact with the drive member in the displacement input section and applying the moving force to the displacement input section, the drive member being two flat plates made of an elastic material A first length in the first axial direction and a predetermined distance between the two flat plate members, and the two flat plate members in the first axial direction. Two pieces to be joined in a substantially parallel state with a distance of A spacing member and a second length that is longer than the first length in the first axial direction, and are disposed between the two flat plate members and between the two spacing members. it is said a large distance between members to spread apart in the second length between the spacing member in the two flat plate members, wherein the two spacing members are between the displacement input portion, wherein the flat plate member site is spread is apart by spacing expansion member is characterized Rukoto set to the displacement output portions (claim 1 1).

  According to this configuration, the interval between the two flat plate members joined substantially in parallel with a predetermined interval by the interposition of the interval holding member is configured to be expanded by the interval expanding member. In other words, the plate member is not subjected to special bending or the like, and the plate member is deformed by the insertion of the interval increasing member to obtain a mechanism corresponding to the link mechanism. When bending is performed, variations in springback occur due to unevenness of the material, rolling directionality, etc., and it is difficult to create the same part. However, according to the above configuration, since the joined body of flat plate members is used, the dimensional stability is improved and the assembly can be easily performed.

In this case, the two flat plate members have the same planar shape of a rectangle, the both end positions of the major axis direction, it is not to desired the two spacing members is arranged. According to this configuration, it is possible to create a drive device having a large displacement and a stable amount using a simple component such as a rectangular flat plate member. In addition, it is easy to reduce the size of the drive device.

  Alternatively, the two flat plate members have the same planar shape including a hollow portion capable of containing the driven object at the center thereof, and the two spacing members are disposed with the hollow portion interposed therebetween. It is desirable that the two flat plate members are joined (claim 12). According to this configuration, it is possible to easily create a drive device that includes the driven object in the center.

In the above configuration, the flat plate member has a thickness that is substantially reduced in width in the minor axis direction at a center position in the major axis direction and both end positions inside the spacing member. It is desirable to have an easily deformable part formed by reducing the amount of the above (Claim 1 3 ). According to this configuration, when a moving force is applied from the shape memory alloy actuator, the flat plate member is easily bent in the easily deformable portion. Therefore, for example, it is possible to positively curve the flat plate member so as to maintain a form that can increase the displacement (for example, a rhombus in a side view), thereby obtaining a large amount of displacement. Further , the easily deformable portion can be easily formed on the rectangular flat plate member by punching the edge portion, drilling, etching, or the like.

A drive mechanism according to still another aspect of the present invention uses the drive device, the driven object is a lens unit, and the drive device preferably moves the lens unit in an optical axis direction (claims). Item 14 ). According to this configuration, the lens unit can be freely moved in the optical axis direction by the driving device. Therefore, it is possible to provide a drive mechanism suitable for a high-performance image pickup optical system that is excellent in incorporation into a small image pickup apparatus such as a mobile phone and is compatible with autofocus and optical zoom.

In the above-described configuration using the interval expansion member, and the lens unit, and a driving device according to any one of claims 1 1 to 13, moving the lens unit in a predetermined optical axis direction, the distance enlargement member, it is desirable that provided integrally with the lens unit (claim 15). According to this configuration, since the interval enlarging member is integrated with the lens unit, the number of parts can be reduced.

An image pickup apparatus according to still another aspect of the present invention includes a drive mechanism according to claim 14, an image pickup element disposed on an image plane side of the lens unit, and a control unit that controls the operation of the drive mechanism. (Claim 16 ). According to this configuration, by mounting the drive mechanism having the above-described advantages, it is possible to provide an imaging device such as a mobile phone that is small in size and excellent in impact resistance.

  ADVANTAGE OF THE INVENTION According to this invention, in the drive device which applied the SMA actuator, the drive device which can obtain a big displacement amount is small and lightweight. For example, when the driving is applied to driving of a lens unit, the driving is suitable for a high-performance imaging optical system that is excellent in incorporation into a small imaging device such as a device mobile phone and can handle autofocus and optical zoom. A mechanism can be provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 1 is an exploded perspective view showing main components of a lens driving module S (imaging device) including a driving mechanism according to the first embodiment. The lens driving module S generally includes a lens unit 10 (driven object), a driving member 20 that moves the lens unit 10 in the optical axis AX direction (first axis direction), and an SMA actuator 30. It consists of On the image plane side of the lens unit 10, an image sensor 40 that photoelectrically converts a subject light image is arranged.

  The lens unit 10 has a cylindrical shape, and includes a photographing lens 100, a lens driving frame 11 that holds the photographing lens 100, and a lens barrel 13 in which the lens driving frame 11 is housed. The photographing lens 100 includes an objective lens, a focus lens, a zoom lens, and the like, and constitutes an imaging optical system for subject images with respect to the image sensor 40. The lens drive frame 11 is a so-called ball frame, and is moved together with the lens barrel 13 in the direction of the optical axis AX. A pair of support portions 12 are provided on the outer peripheral wall portion at the distal end on the objective side of the lens drive frame 11 so as to protrude 180 degrees in the circumferential direction. In the support portion 12, the lens unit 10 is engaged (supported) with the drive member 20.

  The driving member 20 is provided with a displacement input unit 20in to which an input of a moving force in a direction orthogonal to the optical axis AX (second axis direction) is applied, and the optical axis AX direction based on the moving force applied to the displacement input unit 20in. The displacement output unit 20out is moved. The support unit 12 of the lens unit 10 is fixed to the displacement output unit 20out. This drive member 20 has a rectangular link similar to the first drive piece 20A having a form in which four inclined arms are linked in a square (diamond) shape so as to have a hollow portion H that can contain the lens unit 10. And a second drive piece 20B having a configuration.

  The first drive piece 20A is formed of a thin sheet-like member having a predetermined strength (strength that can drive the lens unit 10) as a whole, and includes four flat surfaces (first flat surface 21 and A second flat surface 22) and four arms 23 connecting the flat surfaces. The second driving piece 20B is also made of a similar sheet-like member, and 4 flat surfaces (third flat surface 24 and fourth flat surface 25) located at the apex of the quadrangle and 4 connecting these flat surfaces. One arm 26 is provided.

  Here, out of the four flat surfaces of the first drive piece 20A, two apex portions facing each other and having a trapezoidal shape in a top view (see FIG. 2) and having a relatively large area are defined as a first flat surface 21. The other two apex portions facing each other and having a substantially rectangular shape and a relatively small area are defined as a second flat surface 22. The second flat surface 22 exists at a position shifted from the first flat surface 21 to the front side (object side) in the optical axis AX direction. The four arms 23 that respectively connect the first flat surface 21 and the second flat surface 22 are inclined upward as viewed from the first flat surface 21 side due to the shift of the positional relationship. Actually, the first flat surface 21 and the second flat surface 22 and the arm 23 are integrated, and the first flat surface 21 and the second flat surface 21 are formed by bent portions 23b (bent portions) provided in the vicinity of each vertex of the quadrangle. Two flat surfaces 22 are defined.

  The second driving piece 20B also has a trapezoidal shape and two apexes facing each other having a relatively large area as the third flat surface 24, and other opposing facing parts having a substantially rectangular shape and a relatively narrow area. Two apex portions are defined as a fourth flat surface 25. The fourth flat surface 25 exists at a position shifted from the third flat surface 24 to the rear side (image side) in the optical axis AX direction. The four arms 26 respectively connecting the third flat surface 24 and the fourth flat surface 25 are inclined downward as viewed from the third flat surface 24 side due to the shift of the positional relationship. Similarly, the third flat surface 24, the fourth flat surface 25, and the arm 26 are integrated, and are provided by bent portions (not indicated in the drawing) provided near the vertices of the quadrangle. The third flat surface 24 and the fourth flat surface 25 are partitioned.

  The first drive piece 20A and the second drive piece 20B are arranged back and forth in the direction of the optical axis AX so as to face each other so that the first flat surface 21 and the third flat surface 24 abut each other. Has been. The first flat surface 21 and the third flat surface 24 are coupled and integrated by a rivet 212. This connection may be spot welding or fixing by an adhesive. On the other hand, as a result of such coupling, the second flat surface 22 of the first drive piece 20A and the fourth flat surface 25 of the second drive piece 20B are positioned back and forth in the optical axis AX direction. Yes. Thereby, the drive member 20 has a pantograph-type three-dimensional shape.

  The constituent material of the first drive piece 20A and the second drive piece 20B is not particularly limited, and has a strength capable of transmitting the drive force, while the bent portion 23b can be elastically deformed to serve as a node. If it is good. For example, a metal sheet or a resin sheet can be used. In particular, it is desirable to use a resin material that has a low bending elastic modulus so that a loss of force due to elastic deformation at the bent portion 23b is small, a high bending strength that is difficult to break due to elastic deformation, and excellent heat resistance. Examples of such a resin material include polycarbonate and polyethylene terephthalate.

  In such a drive member 20, the two vertex portions of the quadrangle, which is a portion where the first flat surface 21 and the third flat surface 24 are joined, serve as the above-described displacement input unit 20in. In addition, the second flat surface 22 of the first driving piece 20A, which is the other two apex portions, serves as the above-described displacement output unit 20out. Accordingly, the support portion 12 of the lens unit 10 is engaged with the second flat surface 22. Furthermore, the 4th flat surface 25 of the 2nd drive piece 20B is set as the fixing | fixed part fixed to the base member 51 (refer FIGS. 2-4) which is unmovable. In addition, on the outer peripheral edge of the displacement input portion 20in, guide pieces 211 (construction portions) to which a moving force (moving force in a direction perpendicular to the optical axis) from the SMA actuator 30 toward the optical axis center is provided diagonally. Each projectes.

  The SMA actuator 30 is a linear actuator made of a shape memory alloy (SMA) wire (single linear body) such as a Ni-Ti alloy. The SMA actuator 30 expands when given a predetermined tension at a low temperature and a low elastic modulus (martensite phase). When heat is applied in this extended state, the SMA actuator 30 undergoes phase transformation and a high elastic modulus (austenite). Phase (matrix) and return to its original length (recover shape) from the stretched state.

  In this embodiment, the structure which performs the above-mentioned phase transformation by energizing and heating the SMA actuator 30 is employ | adopted. That is, since the SMA actuator 30 is a conductor having a predetermined resistance value, Joule heat is generated by energizing the SMA actuator 30 itself, and transformation from the martensite phase to the austenite phase is performed by self-heating based on the Joule heat. It is supposed to be configured. For this reason, the first electrode 31 a and the second electrode 31 b (see FIGS. 2 and 3) for energization heating are fixed to both ends of the SMA actuator 30. Further, as will be described in detail later, the SMA actuator 30 is stretched over the guide piece 211 of the displacement input unit 20in, and a moving force accompanying shape recovery by heating is applied to the displacement input unit 20in.

  The image sensor 40 photoelectrically converts and outputs R, G, and B component image signals according to the amount of light of the optical image of the subject imaged by the lens unit 10. For example, as the imaging device 40, color filters of R (red), G (green), and B (blue) are checkered on the surface of each CCD of an area sensor in which CCDs (Charge Coupled Devices) are two-dimensionally arranged. It is possible to use a single plate type color area sensor called a Bayer method that is attached in a shape. In addition to such a CCD image sensor, a CMOS image sensor, a VMIS image sensor, or the like can also be used.

  Next, the overall structure of the lens driving mechanism will be described. 2 is a plan view of the lens driving mechanism 200 according to the first embodiment in a top view (a plan view with the top plate 52 removed), and FIG. 3 is a side view of the lens driving mechanism 200. The lens driving mechanism 200 includes a base member 51, a top plate 52, a parallel plate spring 53, and a bias spring 54 in addition to the lens unit 10, the driving member 20, and the SMA actuator 30 described above. The assembly structure of the lens drive mechanism 200 is roughly as follows. The drive member 20 containing the lens unit 10 is sandwiched from above and below by the base member 51, the top plate 52, and the parallel plate spring 53, and the bias spring 54 is the lens unit. 10 on the object side. And the SMA actuator 30 is constructed so that the circumference | surroundings of the square-shaped drive member 20 may be surrounded by top view.

  The base member 51 is a member that is fixed to a member (for example, a frame of a mobile phone or a mount substrate) to which the lens driving mechanism 200 is attached, and is an immovable member that forms the bottom side of the lens driving mechanism 200. FIG. 4 is a top plan view showing the shape of the base member 51. The base member 51 is made of a square plate made of resin (insulator), and includes a through hole 51H, a support column 511, an electrode fixing portion 512, and a tension guide 513.

  The through hole 51 </ b> H is for allowing the optical image from the lens unit 10 to pass to the image sensor 40, and is formed at a substantially central portion of the base member 51. The support columns 511 are for supporting the top plate 52, and four of them are erected one by one along the diagonal line. Among these, one pair of support | pillars 511 is standingly arranged in the position comparatively near the through-hole 51H so that the hollow part H of the drive member 20 may be penetrated. On the other hand, the other pair of columns 511 is erected near the corner of the base member 51.

  The electrode fixing portion 512 is for supporting the first electrode 31 a and the second electrode 31 b of the SMA actuator 30, and two of them are erected substantially adjacent to one corner of the base member 51. The height of the electrode fixing portion 512 is about half that of the support column 511, whereby the first electrode 31 a and the second electrode 31 b are supported at a substantially intermediate position between the base member 51 and the top plate 52. In FIG. 2 and FIG. 3, the electrode fixing portion 512 is not shown for simplification of illustration.

  The tension guide 513 is used to construct the SMA actuator 30 along the quadrangular shape of the driving member 20, and one tension guide 513 is erected in the diagonal direction of the electrode fixing portion 512. The tension guide 513 has the same height as the support column 511. However, since the support function of the top plate 52 is not necessary, it may be anything that is slightly higher than the height of the electrode fixing portion 512. Further, it is desirable that a portion where the SMA actuator 30 is bridged is provided with a concave curved surface for bridging the wire.

  As shown in FIG. 2, the SMA actuator 30 is installed on the electrode fixing unit 512 and the tension guide 513 and the guide pieces 211 of the two displacement input units 20 in, and is extended around the drive member 20. That is, the SMA actuator 30 is configured such that the guide piece 211 of the one displacement input portion 20in and the other displacement output portion are based on one electrode fixing portion 512 disposed in the vicinity of the one displacement output portion 20out of the drive member 20. The tension guide 513 located in the vicinity of 20 out and the guide piece 211 of the other displacement input portion 20 in go around and return to the other electrode fixing portion 512 located near the one displacement output portion 20 out again. Has been passed.

  By such a bridge, the contact portion between the SMA actuator 30 and the drive member 20 is substantially only the portion of the two guide pieces 211. As a result, the portion where the linear SMA actuator 30 and the driving member 20 rub against each other is limited only to the contact portion with the guide piece 211 (displacement input portion 20in), so that the driving force generated by the SMA actuator 30 is highly efficient. It can be given to the drive member 20. It is desirable that the guide piece 211 is also provided with a concave curved surface for bridging the wire.

As described above, it is desirable that the driving member 20 and the SMA actuator 30 are substantially in a point contact state. However, the drive member 20 and the SMA actuator 30 are configured to contact each other with a certain contact length including at least the displacement input portion. May be. In this case, when the total length of the SMA actuator 30 is L, the contact length C of the SMA actuator 30 with respect to the drive member 20 is
C ≦ L / 2
It is desirable to satisfy In this way, the portion where the SMA actuator 30 and the driving member 20 rub against each other is restricted to L / 2 or less, so that the driving force generated by the SMA actuator 30 can be efficiently applied to the driving member 20. Further, the SMA can be efficiently heated and cooled, and the responsiveness can be improved.

  The top plate 52 functions as a lid that protects the driving member 20 and also serves to hold the upper leaf spring 53 a of the parallel leaf spring 53. FIG. 5 is a plan view showing the shape of the top plate 52. The top plate 52 is made of a square plate made of metal or resin, and includes a through hole 52H provided near the center thereof. As described above, the top plate 52 is supported and fixed in a state parallel to the base member 51 by the four support columns 511 provided upright on the base member 51.

  The through hole 52H includes a center hole 521 for preventing the object light from entering the lens unit 10 and a pair of extending portions 522 extending from the center hole 521 in one diagonal direction. The center hole 521 has an inner diameter large enough to receive the lens unit 10. The extension portion 522 corresponds to the protruding position of the support portion 12 of the lens unit 10 and has a slightly larger shape than the support portion 12. By providing the through hole 52H, the top plate 52 can be attached to the support column 511 after the lens unit 10 having a longer length in the optical axis AX direction than the support column 511 is installed on the base member 51. ing.

  The parallel leaf spring 53 functions as a restricting member that restricts the degree of freedom of displacement of the lens unit 10 in one direction along the optical axis AX, and includes an upper leaf spring 53a and a lower leaf spring 53b arranged in parallel. Become. FIG. 6 is a plan view showing the shape of the parallel leaf springs 53 (the upper leaf spring 53a and the lower leaf spring 53b). The parallel leaf spring 53 includes an outer frame portion 531, a ring portion 532, a beam portion 533, and a column hole 534. The upper leaf spring 53 a is attached on the top plate 52, and the lower leaf spring 53 b is attached on the base member 51.

  The outer frame portion 531 of the upper leaf spring 53 a is fixed to the top plate 52. On the other hand, the outer frame portion 531 of the lower leaf spring 53 b is fixed to the base member 51. On the other hand, the ring portions 532 are each fixed to the lens unit 10 side. That is, the ring portion 532 of the upper leaf spring 53 a is attached so as to be interposed between the upper end side of the lens unit 10, more precisely, the lower surface of the upper end flange portion of the lens driving frame 11 and the upper end edge of the lens barrel 13. . Further, the ring portion 532 of the lower leaf spring 53 b is attached to the lower end surface of the lens unit 10. The reason why the shape of the ring portion 532 is a ring shape is that the passage of subject light is not hindered.

  The beam portion 533 bridges the outer frame portion 531 and the ring portion 532, and is not fixed to either the top plate 52 or the base member 51. The beam portion 533 extends in an approximately L shape outwardly from the outer periphery of the ring portion 532 at an interval of 90 degrees so that the lens unit 10 can move in one direction along the optical axis AX. It has a connected shape. When the upper and lower sides are sandwiched between the ring portions 532 supported by the four beam portions 533, the degree of freedom of the lens unit 10 becomes one degree of freedom along the optical axis AX.

  The lens driving mechanism 200 according to the present embodiment has a function of essentially moving the lens unit 10 in the direction of the optical axis AX. However, the lens unit 10 may move with an inclination from the optical axis AX due to a slight balance deviation that may occur during assembly. Therefore, by mounting the parallel leaf spring 53, such a tilting movement is suppressed, and the lens unit 10 is moved with high accuracy along the optical axis AX.

  A pair of support hole 534 is provided in one diagonal direction of the outer frame portion 531. The column holes 534 are for penetrating a pair of columns 511 located on the diagonal line on the displacement output unit 20out side. Therefore, the support hole 534 is provided only in the lower leaf spring 53b. A pair of columns 511 positioned on the diagonal line on the displacement input unit 20 in side passes through the gap between the outer frame portion 531 and the ring portion 532.

  The bias spring 54 (biasing means) biases the lens unit 10 in the optical axis direction in a direction opposite to the direction in which the displacement output unit 20out is moved by the operation (contraction) of the SMA actuator 30. The bias spring 54 is formed of a compression coil spring having a diameter substantially matching the peripheral size of the lens driving frame 11, and one end side (lower end side) is in contact with the top surface of the lens driving frame 11. Note that the other end side (upper end side) of the bias spring 54 comes into contact with, for example, the inner surface of the housing of the mobile phone.

  The force of the bias spring 54 is weaker than the moving force of the displacement output unit 20out. That is, when the SMA actuator 30 is not operating, the lens unit 10 is pressed toward the base member 51 (downward in FIG. 3), while when the SMA actuator 30 is operated, the lens unit 10 resists the pressing force of the bias spring 54. Then, the lens unit 10 is moved in the opposite direction (upward in FIG. 3). In other words, the bias spring 54 gives the lens unit 10 a biasing force for returning the lens unit 10 to the home position after the operation of the SMA actuator 30 is completed. By assembling such a bias spring 54, a bias force is always applied to the lens unit 10. Therefore, the lens unit 10 can be returned to the home position by controlling the energization amount to the SMA actuator 30, and the drive control can be performed. It becomes easy to do.

  Next, the mechanical operation of the lens driving mechanism 200 configured as described above will be described. FIG. 7 is a side view showing a state in which the SMA actuator 30 is contracted by energization heating (FIG. 3 is a side view in a state in which the SMA actuator 30 is not operating). FIG. 8 is a diagram showing the drive member 20 and the SMA actuator 30 extracted. FIG. 8A shows a plan view in top view, and FIG. 8B shows a side view.

  When a predetermined voltage is applied between the first electrode 31a and the second electrode 31b of the SMA actuator 30 and the SMA actuator 30 is heated by being energized and transformed into the austenite phase, the SMA actuator 30 generates contractile force. This contraction force acts on the two guide pieces 211 respectively protruding from the displacement input portion 20in of the drive member 20 on which the SMA actuator 30 is bridged. That is, the moving forces F11 and F12 from the outer direction opposite to each other by 180 degrees toward the center of the optical axis AX are given to the displacement input unit 20in.

  In response to the moving forces F11 and F12, the drive member 20 is deformed so that its height dimension extends in the direction of the optical axis AX. That is, the bent portion 23b shown by a dotted line in FIG. 8A is bent by the moving forces F11 and F12, respectively, and the bent portion 23b functions as a node, so that the second flat surface of the first drive piece 20A is obtained. The drive member 20 is deformed so that the distance between the surface 22 and the fourth flat surface 25 of the second drive piece 20B is expanded. Here, since the fourth flat surface 25 is fixed to the base member 51, only the second flat surface 22 of the first drive piece 20A constituting the displacement output unit 20out is provided on the object side along the optical axis AX. Thus, a moving force F2 that extends is generated.

  The moving force F2 is transmitted from the second flat surface 22 to the lens unit 10 via the support portion 12, and the lens unit 10 is displaced in the optical axis AX direction. At this time, the beam portions 533 of the upper leaf spring 53a and the lower leaf spring 53b are warped upward (object side), and the bias spring 54 is compressed.

  When energization to the SMA actuator 30 is stopped (or the voltage is reduced to a predetermined value) and the SMA actuator 30 is cooled and returned to the martensite phase, the moving forces F11 and F12 applied to the displacement input unit 20in are Disappear. Then, the biasing force of the bias spring 54 returns the lens unit 10 to the home position along the optical axis AX direction (returns to the state shown in FIG. 3). In this way, the lens unit 10 can be displaced along the optical axis AX direction by energizing the SMA actuator 30 on and off. Further, the amount of displacement of the lens unit 10 can be adjusted by controlling the energization current to the SMA actuator 30 to adjust the force of the moving forces F11 and F12.

  Here, in the present embodiment, one SMA actuator 30 is disposed between the two guide pieces 211 and the middle of these guide pieces 211 with the fixing portion of the first electrode 31a and the second electrode 31b as a base point. The two tension guides 513 are used to extend in a quadrangular shape along the outer periphery of the drive member 20. Therefore, the intermediate point of the entire length of the SMA actuator 30 is supported by the tension guide 513, and is provided between the tension guide 513 and the fixing portion of the first electrode 31a, and between the tension guide 513 and the second electrode 31b. The relationship is such that the piece 211 is located.

  For this reason, since the SMA actuator 30 performs expansion and contraction by the same amount of displacement at half intervals with the tension guide 513 as a boundary, the SMA actuator 30 is not rubbed at the support portion (contact portion) by the tension guide 513. Similarly, the SMA actuator 30 is not rubbed even at the support portion by the guide piece 211 because the same amount of displacement is expanded and contracted by half even with the guide piece 211 as a boundary. Therefore, the loss of power due to rubbing is suppressed to a minimum, and damage to the SMA actuator 30 due to friction is prevented in advance. In addition, since there is no sliding part or gear meshing part, the number of parts is small, the occurrence of backlash and the like can be avoided, and furthermore, backlash does not occur, so the response of the lens unit 10 is smooth with good output efficiency. Drive can be performed.

  Further, according to the lens driving mechanism 200 of the present embodiment, the displacement due to the contraction of the SMA actuator 30 is enlarged in two stages and transmitted to the displacement output unit 20out. That is, by assembling the driving member 20 and the SMA actuator 30 as described above, a displacement larger than the actual contraction amount of the SMA actuator 30 can be input to the driving member 20 (first stage of the displacement expanding function) and driving. The link mechanism of the member 20 can further increase the displacement (second stage of the displacement expansion function). Thereby, although the contraction amount of the SMA actuator 30 is several percent of the total length, a large displacement can be given to the lens unit 10. Hereinafter, these displacement enlargement functions will be described in detail.

[1] First Stage of Displacement Enlargement Function FIG. 9 is a schematic diagram showing the relationship between the contraction displacement of the SMA actuator 30 and the displacement of the drive member 20. As shown in FIG. 9A, in the initial state where the SMA actuator 30 is not energized via the first electrode 31a and the second electrode 31b, the SMA actuator 30 is in a state indicated by a solid line in the figure. On the other hand, when energized and heated, a contracted state 30S indicated by a dotted line in the figure is obtained. Reference numerals p1 and p3 in the drawing each indicate a construction point to the guide piece 211, and reference numeral p2 denotes a construction point to the tension guide 513. In this case, the SMA actuator 30 does not move at the point p2, but at the points p1 and p3, the displacement can be inputted by the distance a on one side.

  FIG. 9B is a circle drawn with the distance from the point p2 to the point p1, which is the displacement input unit, as the radius. The solid line circle 32 is in a state where the SMA actuator 30 is not contracted, and the dotted line circle 32S is contracted. Each state is shown. In this case, the actual contraction amount of the SMA actuator 30 is the distance d along the radial direction (the difference in radius between the solid circle 32 and the dotted circle 32S). However, the moving distance a of the point p1 is larger than the distance d. That is, it can be seen that a displacement larger than the actual contraction amount of the SMA actuator 30 can be input at the points p1 and p3.

  This is because the SMA actuator 30 is bent at a point p1, which is an intermediate point from the first electrode 31a to the point p2, and the contraction force is not the overhead direction of the SMA actuator 30, but the center direction of the bending angle (that is, the optical axis). By acting on the center of AX). Further, as the tension angle θ of the SMA actuator 30 decreases, the displacement input amount increases as indicated by the movement distance a ′ and the movement distance a ″ in the drawing.

[2] Second Stage of Displacement Enlarging Function The link mechanism of the drive member 20 as shown in FIG. 8B is a four-joint link mechanism having arms 230 of equal length r as shown in FIG. Can be considered. As indicated by the solid line, in the state where the inclination angle of the arm 230 is θ ₀ , when an input displacement b is applied from the portion corresponding to the left and right nodes (displacement input unit 20 in) toward the center in the left-right direction, the arm 230 As shown by 203F, it tilts, and the tilt angle changes to θ _f larger than θ ₀ . As a result, an output displacement c is generated at the upper and lower nodes.

FIGS. 11A to 11C are diagrams schematically illustrating the relationship between the input displacement b and the output displacement c. 11 (a) is a tilt angle theta ₁₁ in the initial state of the arm 230 indicated by the solid line, tilt center angle theta ₁₃ between the tilt angle theta ₁₂ of the arm 230F after displacement indicated by the dotted line is a [pi / 4 Shows the case. In other words, the tilt angle theta ₁₁ of the arm 230 in the initial state, the inclination angle theta ₁₂ of the arm 230F after displacement, even when a target around the [pi / 4, it can be expressed by the following formula .
θ ₁₂ −θ ₁₃ (π / 4) = θ ₁₃ (π / 4) −θ ₁₁

In this case the tilt center angle theta ₁₃ is [pi / 4, the displacement of the upper and lower sections relative to the displacement of the left and right section 1: 1. Therefore, the input displacement b ₁ and the output displacement c ₁ are equal. Therefore, in this case, the displacement enlargement function cannot be obtained.

On the other hand, in FIG. 11B, the inclination central angle θ ₂₃ between the inclination angle θ ₂₁ in the initial state of the arm 230 indicated by a solid line and the inclination angle θ ₂₂ of the arm 230F after displacement indicated by a dotted line is π The case where it is smaller than / 4 is shown. In this case, output displacement c ₂ for the input displacement b ₂ as shown is enlarged. That is, the relationship of input displacement b ₂ <output displacement c ₂ is established.

On the other hand, FIG. 11 (c), the tilt angle theta ₃₁ in the initial state of the arm 230 indicated by the solid line, tilt center angle theta ₃₃ between the tilt angle theta ₃₂ of the arm 230F after displacement indicated by a dotted line, [pi / The case where it is larger than 4 is shown. In this case, output displacement c ₃ to the input displacement b ₃ as shown is reduced. That is, the relationship of input displacement b ₂ > output displacement c ₂ is established.

  From the above, by setting the inclination angle of the arm 230 in the link mechanism as shown in FIG. 11 (b), the displacement expansion function can be obtained in the link mechanism. In actual assembly, considering the stroke required for focusing and zooming of the lens unit 10, the inclination angle of the arm 230 when the lens unit 10 is at the home position (inclination angle with respect to the line connecting the two displacement input portions) and The displacement enlargement function can be obtained by setting the inclination central angle between the inclination angle of the arm 230 when moved to the maximum to be π / 4 or less.

  Note that the smaller the tilt angle, the greater the displacement expansion function, but the smaller the output force. That is, the driving power of the lens unit 10 decreases. For this reason, it is not preferable to make the inclination center angle too small, and the ratio of the input displacement b to the output displacement c is about 1: 1.5 to 7, preferably 1: 3 in consideration of power and displacement. It is desirable to select the tilt center angle so as to be about ˜6. For example, when the driving power is given priority over the displacement enlarging function, the tilt center angle may be set to π / 4, or π / 4 or more, as shown in FIGS. 11A and 11C. .

  As described above, the drive member 20 according to the first embodiment has a two-stage displacement expansion function, and the displacement input unit 20in is given a first displacement amount larger than the displacement of the SMA. In this case, a second displacement amount larger than the first displacement amount can be output from the displacement output unit 20out. Thereby, the lens unit 10 can be given a displacement that is two steps larger than the actual displacement of the SMA actuator 30. Therefore, even if the displacement amount of the SMA actuator 30 is small, it is possible to obtain a lens movement amount necessary for autofocus and optical zoom.

  Subsequently, a control configuration of the lens driving mechanism 200 according to the present embodiment will be described. FIG. 12 is a block diagram showing the control means 60 of the lens driving mechanism 200. The control means 60 includes a voltage supply circuit 61, a displacement sensor 62, and a lens drive control unit 63.

  The voltage supply circuit 61 is a driver of the SMA actuator 30 and applies a predetermined driving voltage to the SMA actuator 30 to heat it and generate a driving force. The voltage supply circuit 61 and the first electrode 31a and the second electrode 31b of the SMA actuator 30 are electrically connected by a lead wire, and the drive voltage generated in the voltage supply circuit 61 is SMA via the lead wire. Applied to the actuator 30.

  The displacement sensor 62 includes an optical position detection sensor such as a light reflection sensor or a photo interrupter, a magnetic position detection sensor using a Hall element, and the like, and detects position information of the lens unit 10. is there. The position information detected by the displacement sensor 62 is output to the lens drive control unit 63. The displacement sensor 62 is disposed at an appropriate position near the lens unit 10.

  The lens drive control unit 63 includes a microcomputer or the like, and controls the drive voltage supplied from the voltage supply circuit 61 to the SMA actuator 30. That is, the lens drive control unit 63, for example, in accordance with the movement target value of the lens unit 10 obtained based on the position control signal for autofocus and optical zoom and the current position information detected by the displacement sensor 62. A control signal for driving the actuator 30 is generated. This control signal is supplied to the voltage supply circuit 61, and a drive voltage corresponding to the movement target value is generated by the voltage supply circuit 61. By providing such a control means 60, the lens unit 10 can be positioned on the optical axis AX.

  FIG. 13 is a block diagram showing a control unit 60 ′ of the lens driving mechanism 200 according to another embodiment. The control means 60 ′ includes a voltage supply circuit 61 and a lens drive control unit 63 similar to those described above, and a RAM (Random Access Memory) 64 that stores control information of the lens unit 10.

  The shape memory alloy has a characteristic that the resistance value changes according to the phase change between the martensite phase and the austenite phase. 14 (a) and 14 (b) are graphs showing the relationship between the amount of displacement due to phase change and the resistance value, and FIG. 14 (a) shows the relationship between the amount of displacement and the resistance value during heating of the shape memory alloy. FIG. 14B shows the relationship between the displacement and the resistance value during cooling.

  The RAM 64 stores the above-described characteristics for the SMA actuator 30 used in the lens driving mechanism 200 in advance, and stores data in which the relationship between the displacement and the resistance value is tabulated. Then, the lens drive control unit 63 performs a process of obtaining a drive voltage from the table of the RAM 64 based on the position control signal of the lens unit 10 and the current resistance value while detecting the resistance value of the SMA actuator 30. According to the control means 60 ', since it is not necessary to provide a separate displacement sensor or the like, it is possible to provide the lens driving mechanism 200 that is smaller and less expensive.

  Next, an embodiment in which the lens driving mechanism 200 according to this embodiment is incorporated in an imaging apparatus will be described. FIG. 15 is an external configuration diagram of a camera-equipped mobile phone 70 as an example of an imaging apparatus. Here, a case where the lens driving mechanism 200 is incorporated in order to give an autofocus function and an optical zoom function to the lens unit 10 which is a component part of the camera unit OP built in the camera-equipped mobile phone 70 is illustrated. ing. In addition to the camera-equipped mobile phone 70, the lens driving mechanism 200 according to the present embodiment is capable of imaging an imaging lens unit built-in digital still camera, digital video camera, or personal digital assistant (PDA). The present invention can also be suitably applied to an apparatus.

  FIG. 15A is a perspective view showing the front (operation surface) of the camera-equipped mobile phone 70, and FIG. 15B is a perspective view showing the back. The camera-equipped cellular phone 70 has a foldable structure in which a first casing 71 and a second casing 72 are connected by a hinge 73 as shown in FIG. An LCD (Liquid Crystal Display) 74 as a display unit for various information is provided on the front surface of the first housing 71, and a key input unit 75 is provided on the front surface of the second housing 71. . Further, as shown in FIG. 15B, the camera unit OP including the lens unit 10 is built in the back surface of the first housing 71 in a manner in which the objective lens is exposed.

  The key input unit 75 includes various dial buttons for operating a mobile phone function, a mode setting button for starting an image shooting mode and switching between still image and moving image shooting, and the lens unit 10 provided in the camera unit OP. A zoom button for controlling the optical zoom (magnification) operation, a shutter button for executing a photographing operation, and the like are included.

  FIG. 16 is a block diagram showing a schematic electrical configuration of the camera-equipped mobile phone 70. In addition to the lens driving mechanism 200 and the image sensor 40 including the lens unit 10 described above, the camera-equipped cellular phone 70 includes a timing generator (TG) 81, an analog front end (AFE) 82, an image processing unit 83, and an image memory. 84, an overall control unit 85, a shutter drive unit 86, a voltage supply circuit 87, a display unit 88, and an image recording unit 89.

The lens unit 10 constitutes an imaging optical system that takes in an optical image of a subject and guides it to an imaging device 40 disposed on the image side of the lens unit 10. Inside the lens unit 10, a lens group 10 1 for forming an optical image of a subject, a shutter 102 for blocking or passing light is built in the optical path of the imaging optical system. In place of the lens unit 10 1, the aperture 103 is arranged, also on the lens unit 10 1 contains moving lens 104 for performing focus / zoom. An SMA actuator 30 for moving the moving lens 104 in the optical axis direction is attached to the lens unit 10.

  The timing generator 81 controls a photographing operation (charge accumulation based on exposure, reading of accumulated charge, etc.) by the image sensor 40. The timing generator 81 generates a predetermined timing pulse (vertical transfer pulse, horizontal transfer pulse, charge sweeping pulse, etc.) based on the reference clock output from the overall control unit 85 and outputs it to the image sensor 40. The imaging operation is controlled. Further, by generating a predetermined timing pulse and outputting it to the analog front end 82, the A / D conversion operation and the like are controlled.

  The analog front end 82 performs predetermined signal processing on the image signal (analog signal group received by each pixel of the CCD area sensor) output from the image sensor 40, converts the image signal into a digital signal, and outputs the digital signal to the image processing unit 83. To do. The analog front end 82 includes a correlated double sampling circuit for reducing reset noise included in the analog image signal voltage, an auto gain control circuit for correcting the level of the analog image signal, a clamp circuit for fixing the potential indicating the black level, An A / D conversion circuit that converts analog R, G, and B image signals into, for example, a 14-bit digital signal is provided.

  The image processing unit 83 performs predetermined signal processing on the image data output from the analog front end 82 to create an image file. A black level correction circuit, a white balance control circuit, a color complement circuit, a gamma correction circuit, and the like It is configured with. The image data captured by the image processing unit 83 is temporarily written in the image memory 84 in synchronization with the reading of the image sensor 40. Thereafter, the image data written in the image memory 84 is accessed to access the image processing unit. Processing is performed in each of the 83 blocks.

  The image memory 84 temporarily stores the image data output from the image processing unit 83 in the shooting mode, and is used as a work area for performing predetermined processing by the overall control unit 85 on the image data. It is. In the playback mode, the image data read from the image recording unit 89 is temporarily stored.

  The overall control unit 85 includes a CPU (Central Processing Unit) and the like, and performs centralized control of each unit of the camera-equipped mobile phone 70 and also controls shooting operations. That is, the overall control unit 85 performs control of the timing generator 81, the voltage supply circuit 87 and the shutter driving unit 86 for the photographing operation, output control of the image signal, and the like.

  The overall control unit 85 is functionally provided with a focus control unit 851 and a zoom control unit 852. These control units correspond to the camera-equipped mobile phone 70 in the lens drive control unit 63 described with reference to FIG. The focus control unit 851 generates a focus control signal for moving the moving lens 104 to the in-focus position based on predetermined distance measurement information. The zoom control unit 852 generates a zoom control signal for moving the moving lens 104 for optical zooming. These control signals are given to the voltage supply circuit 87.

  The shutter drive unit 86 opens and closes the shutter 102 so that the shutter 102 is opened for a predetermined time according to a shutter open / close control signal given from the overall control unit 85.

  The voltage supply circuit 87 corresponds to the voltage supply circuit 61 described with reference to FIG. 13, and generates a drive voltage for energizing and heating the SMA actuator 30 that drives the moving lens 104. That is, the voltage supply circuit 87 generates a drive voltage for driving the moving lens 104 by the SMA actuator 30 in accordance with the focus control signal and the zoom control signal given from the focus control unit 851 and / or the zoom control unit 852.

  The display unit 88 corresponds to the LCD 74 shown in FIG. 15A, and can display a captured image, a live view image before imaging, and the like. The image recording unit 89 includes a memory card or the like, and stores image data that has been subjected to image processing by the image processing unit 83.

  According to the camera-equipped mobile phone 70 described above, since the lens driving mechanism 200 described above is mounted, since the SMA actuator 30 is used, it is small and lightweight, has excellent impact resistance, has a small number of parts, and is inexpensive. Further, there are advantages that a lens movement amount necessary for autofocus and optical zoom can be secured and that high positional accuracy can be obtained without backlash.

  The embodiment of the drive device (lens drive mechanism 200) according to the first embodiment has been described above. In the first embodiment, for example, the following modified embodiments (1) to (8) are adopted. It is also possible.

(1) Modified Embodiment 1-1: Semi-circular arrangement of SMA actuator In the above-described embodiment, the SMA actuator 30 formed of one linear body is disposed over the substantially entire circumference of the drive member 20 having a quadrangular shape when viewed from above. An example was shown in which it was bridged (see FIG. 8). The arrangement of the SMA actuator with respect to the drive member 20 is not limited to this and can take various forms.

  FIGS. 17A and 17B are diagrams showing an arrangement relationship between the driving member 20 and the SMA actuator 30A according to the modified embodiment 1-1, in which FIG. 17A is a plan view and FIG. 17B is a side view. Yes. Note that in FIG. 17 and the following drawings, the portions denoted by the same reference numerals as those in FIG. 8 indicate the same as those in FIG. 8, and the description thereof is omitted here.

  In the modified embodiment 1-1, the SMA actuator 30 </ b> A has a length corresponding to about a half circumference with respect to the circumference of the drive member 20. That is, the first electrode 31a and the second electrode 31b of the SMA actuator 30A are respectively arranged in the vicinity of the pair of displacement output portions 20out, and the SMA actuator 30A is bridged only on the displacement input portion 20in located on the right side of the drive member 20. It is an aspect.

  In the configuration of the modified embodiment 1-1, as shown in FIG. 17B, the moving force F12 is given only to one displacement input portion 20in, and the driving member 20 is deformed based on the moving force F12. A moving force F21 that causes the displacement output unit 20out to extend in the optical axis direction is generated. According to this configuration, there is an advantage that the amount of SMA used can be halved while ensuring the same amount of displacement of the displacement output unit 20out as in the case of FIG. However, since the displacement input is only one, it is necessary to pay attention to the tilt of the optical axis while the force is reduced to half.

(2) Modified Embodiment 1-2; Multiple Bridges of SMA Actuators FIG. 18 is a diagram showing the positional relationship between the drive member 20 and the SMA actuator 30B according to Modified Embodiment 1-2, and FIG. Is a plan view, and FIG. 18B is a side view. In this modified embodiment 1-2, the SMA actuator 30 </ b> B has a length corresponding to about two rounds with respect to the circumferential length of the driving member 20, and this is doubled around the driving member 20.

  Specifically, a second tension guide 513A is erected between the first electrode 31a and the second electrode 31b arranged on one displacement output portion 20out side, and the second tension guide 513A and its diagonal are arranged. The SMA actuator 30B is bridged around the drive member 20 by two rounds using four installation points of the tension guide 513 positioned at the two and the two guide pieces 211 of the displacement input unit 20in. ing. Of course, the SMA actuator 30B may be rotated two or more times.

  In the configuration of the modified embodiment 1-2, as shown in FIG. 18B, the moving forces F111 and F121 are given to the respective displacement input portions 20in from the double-rolled SMA actuator 30B. The driving member 20 is deformed based on F111 and F121, and a moving force F22 is generated that extends the displacement output unit 20out in the optical axis direction. According to this configuration, although the displacement amount of the displacement output unit 20out is the same as that in FIG. 8, the amount of force input to the displacement input unit 20in is increased by the amount that the SMA actuator 30B is double-wound. There is an advantage that can be.

  FIGS. 19A and 19B are diagrams showing an arrangement relationship between the driving member 20 and the SMA actuator 30C according to another example of the modified embodiment 1-2, FIG. 19A is a plan view, and FIG. 19B is a side view. Respectively. Also in this example, as the SMA actuator 30 </ b> C, a SMA actuator 30 </ b> C having a length corresponding to about 2 turns with respect to the peripheral length of the drive member 20 is used. Similarly, the second tension guide 513B is erected on the one displacement output part 20out side.

  18 differs from the example of FIG. 18 in the manner of bridging the SMA actuator 30C. That is, the first electrode 31a and the second electrode 31b are arranged up and down at the same position, and the SMA actuator 30C is bridged from the first electrode 31a to the tension guide 513 and the two guide pieces 211 counterclockwise. After that, it is folded back by the second tension guide 513B, bridged clockwise along the same route, and returned to the second electrode 31b. Even in this configuration, as shown in FIG. 19B, the moving force F112, F122 having a large force is applied to each displacement input portion 20in from the double-rolled SMA actuator 30C, and these moving forces F112, F122 are applied. Accordingly, the driving member 20 is deformed, and the displacement output unit 20out can generate a large moving force F23 that extends in the optical axis direction.

(3) Modified Embodiment 1-3; Split Overhang of SMA Actuator FIG. 20 is a diagram showing an arrangement relationship between the driving member 20 and the two SMA actuators 30D and 30E according to Modified Embodiment 1-3. FIG. 20A shows a plan view, and FIG. 20B shows a side view. In the third modified embodiment, two SMA actuators 30D and 30E having a length of about a half circumference with respect to the peripheral length of the drive member 20 are used.

  The first electrode 311a and the second electrode 311b of one SMA actuator 30D are arranged in the vicinity of the pair of displacement output units 20out, and the SMA actuator 30D is mounted only on the displacement input unit 20in located on the left side of the drive member 20. Have passed. Further, the first electrode 312a and the second electrode 312b of the other SMA actuator 30E are also arranged in the vicinity of the pair of displacement output portions 20out, and the SMA actuator 30E is mounted only on the displacement input portion 20in located on the right side of the drive member 20. Have passed.

  In the configuration of Modified Embodiment 1-3, as shown in FIG. 20B, a moving force F113 is applied from one SMA actuator 30D to one displacement input unit 20in, and the other displacement input unit 20in is also applied to the other displacement input unit 20in. In contrast, a moving force F123 is applied from the SMA actuator 30E. The driving member 20 is deformed based on the moving forces F113 and F123, and a moving force F24 is generated that extends the displacement output unit 20out in the optical axis direction. According to this configuration, since two SMA actuators 30D and 30E that are relatively short as compared with a single case are used, the current value when the same voltage is applied is increased, and the displacement responsiveness is increased accordingly. There is an advantage that you can.

(4) Modified Embodiment 1-4: Change of Overhead Route of SMA Actuator FIG. 21 is a diagram showing the positional relationship between the drive member 20 and the SMA actuator 30 according to Modified Embodiment 1-4. This modified embodiment 1-4 is substantially the same as the arrangement shown in FIG. 8A, but the position of the tension guide 513 ′ and the fixed positions of the first electrode 31a and the second electrode 31b are viewed from above. However, it is different in that it is set not to the periphery of the drive member 20 but to an empty space existing inside the drive member 20. According to this configuration, a part of the overhead wire path of the SMA actuator 30 enters the drive member 20, and there is an advantage that the size can be reduced accordingly.

(5) Modified Embodiment 1-5; Thinning of Drive Member FIG. 22 is a diagram showing an arrangement relationship between the drive member (first drive piece 20A) and the SMA actuator 30 according to Modified Embodiment 1-5. 22A shows a plan view, and FIG. 22B shows a side view. In this modified embodiment 1-5, the drive member is constituted by a link mechanism having only the upper half of the drive member 20 shown in FIG. 8B, that is, the first drive piece 20A. The displacement input portion 20in of the first drive piece 20A is slidably mounted on a predetermined base member 27.

  In the configuration of Modified Embodiment 1-5, as shown in FIG. 22 (b), moving forces F114 and F115 are applied from the SMA actuator 30 to each displacement input portion 20in, and the first is based on the moving forces F114 and F115. The one driving piece 20A is deformed, and a moving force F25 is generated that extends the displacement output unit 20out in the optical axis direction. According to this configuration, the thickness dimension of the driving member in the optical axis direction can be halved, and there is an advantage that the imaging apparatus can be reduced in thickness.

(6) Modified Embodiment 1-6: Stacking of Drive Members FIG. 23 is a side view showing the positional relationship between the drive member 20 and the SMA actuator 30 according to Modified Embodiment 1-6. In this modified embodiment 1-6, the driving member is configured such that two driving members 20 shown in FIG. 8B are stacked in the optical axis direction (of course, even if three or more driving members 20 are stacked). good). Specifically, the second flat surface 22T of the driving member 20 positioned on the lower side and the fourth flat surface 25B of the driving member 20 positioned on the upper side are connected. The fourth flat surface 25 of the lower drive member 20 is a fixed portion, and the second flat surface 22 of the upper drive member 20 is a displacement output portion 20out.

  In the configuration of Modified Embodiment 1-6, the movement forces F11 and F12 are given from the respective SMA actuators 30 to the total four displacement input portions 20in in the upper and lower two-stage drive members 20, and the movement forces F11 and F12 are applied to the movement forces F11 and F12. Based on this, the drive members 20, 20 are deformed. The two-stage deformation generates a double moving force F2 × 2 that causes the displacement output unit 20out to extend in the optical axis direction. According to this configuration, there is an advantage that the displacement amount of the lens unit 10 can be increased twice as compared with the configuration of FIG.

(7) Modified Embodiment 1-7; Other Link Mechanism FIG. 24 is a diagram showing the positional relationship between the drive member 91 and the SMA actuator 30F according to Modified Embodiment 1-7, and FIG. FIG. 24B is a partially cutaway side view, and FIG. 24C is a cross-sectional view showing the operation. In this modified embodiment 1-7, the drive member 91 has an annular shape with a hollow portion H through which the lens unit 10 can be inserted, and its axial cross-section has a square shape, and a square-shaped bent portion. 911 has a shape located at the outermost part in the radial direction. The square-shaped bent portion 911 serves as a displacement input portion, and the peripheral portion 912 of the square-shaped cross section serves as a displacement output portion.

  On the outer periphery of the bent portion 911 of the drive member 91, four guide pieces 92 project radially at equal intervals of 90 degrees. The SMA actuator 30 </ b> F is stretched over the tip portions of the four guide pieces 92 so as to go around the drive member 91. The first electrode 31 a and the second electrode 31 b connected to both ends of the SMA actuator 30 </ b> F are fixed to the outer peripheral wall of the drive member 91. In this case, the lens unit 10 is inserted into the hollow portion H, and the support portion 12 is assembled in such a manner that it is placed on the peripheral portion 912.

  As shown in FIG. 24C, when the SMA actuator 30 </ b> F is heated and contracted, a moving force toward the center point of the annular drive member 91 is applied to each guide piece 92. As a result, when the SMA actuator 30F is not operating, the driving member 91 whose inner angle of the cross section is φ1 and whose height is g1 receives the moving force and has an inner angle wider than φ1. It becomes φ2 and deforms to g2 whose height is wider than g1. That is, the peripheral portion 912 extends in the optical axis direction. Therefore, the lens unit 10 engaged with the peripheral portion 912 can be moved in the optical axis direction.

  According to this configuration, since the SMA actuator 30F is mounted on the drive member 91 itself, a member for fixing the SMA actuator 30F becomes unnecessary. Therefore, it is possible to reduce the number of parts and further reduce the size.

(8) Other Modified Embodiments Other than the above modified embodiments, the present invention can be further modified and implemented without departing from the gist of the first embodiment. For example, the arms 23 and 26 of the drive member 20 have been illustrated as linearly inclined arms, but instead of them, curved and inclined arms may be used. Further, a rod-shaped member may be used instead of the flat arm. Furthermore, although the example which couple | bonds and integrates the 1st drive piece 20A and the 2nd drive piece 20B with the rivet 212 was shown, it may replace with this and may be made to connect using a hinge mechanism etc. Moreover, although the linear thing was illustrated as the SMA actuator 30, you may make it use a strip | belt-shaped thing. Furthermore, a thing other than the lens unit 10 may be used as the driven object.

[Second Embodiment]
Next, a second embodiment using two flat plate members will be described. FIG. 25 is a side view showing the drive module S1 to which the drive mechanism according to the second embodiment is applied. The drive module S1 includes a driven object 14 and a driving device 400 that moves the driven object 14 in the Z-axis (first axis) direction.

  The driving device 400 includes a driving member and an SMA actuator 430. In the second embodiment, the drive member includes two flat plate members 41 (first flat plate member 41 </ b> A, second flat plate member 41 </ b> B), two spacers 42 (interval holding member), and an interval widening member 43. . FIG. 25 shows a state where the SMA actuator 430 is not operating (shrinking).

  The two flat plate members 41 are made of elastic metal or resin, and are thin plates having a rectangular planar shape that are not particularly bent. Although it is desirable that the first flat plate member 41A and the second flat plate member 41B have the same shape, they may have different shapes. FIG. 25 shows a state in which the first flat plate member 41A is bent upward and the second flat plate member 41B is bent downward. However, in the state where the gap increasing member 43 is not interposed between the two. The first flat plate member 41A and the second flat plate member 41B are members flat in the X-axis direction (see FIG. 28B).

  The two flat plate members 41 are joined by two spacers 42 in a substantially parallel state at a predetermined interval. The spacer 42 is a cylindrical member made of metal or resin and having rigidity. The length of the spacer 42 in the Z-axis direction is selected to be a predetermined length (first length) corresponding to the set separation value between the first flat plate member 41A and the second flat plate member 41B.

  The two spacers 42 are respectively disposed between both end portions 411A in the long axis direction of the first flat plate member 41A and both end portions 411B in the long axis direction of the second flat plate member 41B. The two spacers 42 are not necessarily arranged at the end of the flat plate member 41, and may be arranged with a predetermined distance between the two flat plate members 41.

  A solder layer 413 is provided on a portion of the end portion 411A of the first flat plate member 41A facing the spacer 42. A solder layer 421 is also provided on the end surface of the spacer 42 facing the end portion 411A. These solder layers 413 and 421 are fused to bond them together. Similarly, the end portion 411B of the second flat plate member 41B and the spacer 42 are joined. By such joining, the two flat plate members 41 and the two spacers 42 are integrated to form one casing having a closed space 410. In addition to the solder joint as described above, a method such as joining with an adhesive or welding may be employed.

  The interval enlarging member 43 is a rigid member having a rhombus shape in the XZ axis cross section. The interval expanding member 43 is also interposed between the two flat plate members 41, but is not joined to the two flat plate members 41. The length (second length) between the two vertices 431 and 432 in the Z-axis direction of the interval expanding member 43 is longer than the length of the spacer 42 in the Z-axis direction by a predetermined length. The interval enlarging member 43 is disposed between the two flat plate members 41 and at a central position between the two spacers 42. The upper apex 431 of the interval enlarging member 43 and the lower surface of the central portion 412A of the first flat plate member 41A are in line contact (the symbol Q in the figure indicates the line contact portion), and the lower apex of the interval enlarging member 43 432 and the upper surface of the central portion 412B of the second flat plate member 41B are in line contact.

  As described above, when the gap expanding member 43 whose Z-axis direction dimension is longer than the spacer 42 is inserted between the two flat plate members 41, the first flat plate member 41 </ b> A is located upward with the vertices 431 and 432 as the center of curvature, respectively. The second flat plate member 41B is bent in the downward direction. In other words, the elastically deformed two flat plate members 41 are in a state in which the gap expanding member 43 is sandwiched by the elastic restoring force (bias spring force). Thereby, the housing composed of the two flat plate members 41 and the two spacers 42 has a substantially rhombus shape in a side view. The interval enlarging member 43 does not necessarily have a shape having apexes, but by providing the apexes 431 and 432, there is an advantage that the flat plate member 41 can be curved with high accuracy.

  The lower surface of the central portion 412B of the second flat plate member 41B is fixed to the stationary base member 510. As a result, in this embodiment, the two spacers 42 become the displacement input part 400in, and the central part 412A of the first flat plate member 41A becomes the displacement output part 400out. Accordingly, the driven object 14 is engaged with the upper side surface of the central portion 412A of the first flat plate member 41A.

  The SMA actuator 430 is a linear actuator similar to the SMA actuator 30 in the first embodiment, and has a property of contracting by energization heating. In this 2nd Embodiment, the SMA actuator 430 is spanned on the outer peripheral part of the two spacers 42 used as the displacement input part 400in. Therefore, when the SMA actuator 430 is energized and heated, the movement forces F41 and F42 in the direction facing each other in the X-axis direction are applied to the two spacers 42, respectively.

  When the energization amount for the SMA actuator 430 exceeds a predetermined amount and the moving forces F41 and F42 that overcome the bias spring force by the two flat plate members 41 are generated, the two spacers 42 are attracted to each other. As a result, the two flat plate members 41 are displaced in the Z-axis direction.

  FIG. 26 is a side view showing a state after displacement. Due to the above displacement, the central portion 412A as the displacement output portion 400out generates the moving force F43 in the direction orthogonal to the directions of the moving forces F41 and F42. This moving force F43 has an increased displacement amount, as in the first embodiment. As a result, the driven object 14 is moved in the Z-axis direction (upward direction) larger than the actual contraction amount of the SMA actuator 430.

  Thereafter, when the energization to the SMA actuator 430 is stopped, the two flat plate members 41 are restored to the state shown in FIG. 25 by the bias spring force for returning to the flat plate state of the two flat plate members 41 themselves. That is, when the SMA actuator 430 is gradually cooled by stopping the energization and the bias spring force of the flat plate member 41 exceeds the moving forces F41 and F42, the driven object 14 is returned to the original state without the help of the external bias spring. Returned to the position.

  Generally, the reaction temperature of the shape memory alloy is set to be higher than the temperature range under the usage environment. In many cases, the temperature of the shape memory alloy is controlled by its own Joule heat by energization. By the way, as shown in FIG. 27, when the stress given from the outside is increased, the shape memory alloy has a property that the displacement to the memory shape (length) increases and the reaction temperature increases. However, the reaction temperature is not sufficient even with Ti-Ni shape memory alloys that are widely used because of low hysteresis and relatively high reaction temperature. In view of this, it is common practice to apply a comparatively high external stress to the shape memory alloy by using a bias spring or the like so that the amount of displacement cannot be increased at the reaction temperature while being below the allowable stress.

  However, in a small device using a shape memory alloy used as a set with a bias spring, the size of the bias spring that generates a force equivalent to a stress that increases the amount of displacement becomes so large that it cannot be ignored. On the other hand, according to the present embodiment, part or all of the bias springs can be assigned to the two flat plate members 41, so that the use of a separate bias spring is omitted or reduced. It is possible. Thereby, size reduction of drive mechanism itself can be achieved.

  Further, in the present embodiment, the two flat plate members 41 are not simply bonded at the end portions, but are joined with two spacers 42 interposed therebetween, and the spacers 42 serve as a displacement input portion 400in. Then, the interval between the two flat plate members 41 is expanded by the interval widening member 43, and the two flat plate members 41 are substantially rhombuses corresponding to the link mechanism in a side view (see the rhombus Di indicated by a one-dot chain line in FIG. 25). It is set as the aspect which exhibits a shape. As a result, the input points of the moving forces F41 and F42 by the SMA actuator 430 (contact points between the spacer 42 and the SMA actuator 430) and the apex P in the X-axis direction of the rhombus Di corresponding to the deformation point of the link mechanism are extremely close to each other. Can be made. Accordingly, unintended deformation, loss of force, and the like between the input point of the moving force and the deformation point of the link mechanism are unlikely to occur, and the movement of the driving member can be stabilized.

  Next, an example of the manufacturing method of the drive member concerning 2nd Embodiment is demonstrated based on FIG. First, as shown in FIG. 28A, a first flat plate member 41A and a second flat plate member 41B and two spacers 42 are prepared. In the case where metal plates are used as the first flat plate member 41A and the second flat plate member 41B, a member having an insulating property may be used as the spacer 42. In this case, metal base layers for forming the solder layer 421 are provided on both end faces of the spacer 42. On the other hand, when a resin plate such as a polyimide plate is used as the first flat plate member 41 </ b> A and the second flat plate member 41 </ b> B, a metal member can be used as the spacer 42. In this case, a metal base layer for forming the solder layer 413 is partially provided on the first flat plate member 41A and the second flat plate member 41B. By doing so, there is no current path other than the SMA actuator 430 between the two spacers 42 with which the SMA actuator 430 is in contact, preventing current loss and operating the shape memory alloy actuator with high accuracy. be able to.

  Subsequently, as shown in FIG. 28 (b), spacers 42 are arranged on both ends of the second flat plate member 41B, and the first flat plate member 41A is further placed thereon. In this state, a high temperature environment in which the solder layers 413 and 421 are melted is generated. By such temperature treatment, the first flat plate member 41A and the second flat plate member 41B and the two spacers 42 are solder-bonded to form an integrated casing. At this time, the first flat plate member 41 </ b> A and the second flat plate member 41 </ b> B are in a parallel state with a closed space 410 having a distance d <b> 1 corresponding to the height of the spacer 42.

  Thereafter, as shown in FIG. 28C, a rhombus with a cross section having a distance between the apexes 431 and 432 longer than the spacer 42 in the closed space 410 between the first flat plate member 41A and the second flat plate member 41B. The interval expanding member 43 is inserted. Accordingly, the first flat plate member 41A and the second flat plate member 41B are deformed so as to swell apart from each other at the central portion in the X-axis direction. At this time, the distance between the central portions 412A and 412B is an interval d2 (d1 <d2) corresponding to the distance between the vertices 431 and 432.

  Here, since the space | interval expansion member 43 is a rhombus, it has not only the vertexes 431 and 432 of the Z-axis direction but the vertex 433 (sharp vertex) of the X-axis direction. Therefore, the interval expanding member 43 having the size of the interval d2 can be easily inserted into the closed space 410 in the state of the interval d1 using the vertex 433.

  Thereafter, the central portion 412B of the second flat plate member 41B is fixed to the base member 510, and the SMA actuator 30 is spanned around the two spacers 42. Further, the driven object 14 is engaged with the central portion 412A of the first flat plate member 41A, and the assembly is completed.

  Although the above is an example of the manufacturing method of a drive member, a preferable manufacturing method is a manufacturing method which can apply the soldering apparatus currently used widely. In this case, as the flat plate member 41, a substrate member having a metal conductor pattern formed on a flexible base material such as polyimide foil so as to correspond to the bonding position of the spacer 42 is used. Further, as the spacer 42, a metal member or a member having a metal layer at a joint portion with the flat plate member 41 is used. Then, solder is screen-printed on the substrate member (on the conductor pattern) in a state where the portions other than the conductor pattern portion are masked. Thereafter, the spacer 42 is mounted on the solder layer and heated in a reflow furnace or the like, so that the flat plate member 41 and the spacer 42 are soldered. According to this manufacturing method, the drive member can be easily manufactured using a widely used soldering apparatus.

  FIG. 29 is a side view showing another example of the manufacturing method of the drive member. In this manufacturing method, a first flat plate member 41A 'and a second flat plate member 41B' that have been previously bent are used. That is, as shown in FIG. 29A, the first flat plate member 41A 'and the second flat plate member 41B' are curved in advance so as to be separated from each other at the center. Then, as shown in FIG. 29B, the first flat plate member 41A 'and the second flat plate member 41B' are joined by two spacers 42 to form the shape of the link mechanism.

  The drive member according to the present invention may be produced by such a manufacturing method, but if a flat plate member that has been curved in advance is used, the dimensional accuracy tends to be difficult to obtain. Therefore, it is desirable to apply the drive member according to this manufacturing method to a relatively large drive member or a drive member that does not require much accuracy.

  On the other hand, as shown in FIG. 28, a flat plate member 41 not subjected to special bending processing or the like is used, and these are joined by two spacers 42, and then a flat plate member is inserted by inserting a gap expanding member 43 having a fixed size. When the shape of the link mechanism is formed by deforming 41, the dimensional accuracy is extremely stable. This is because the points where the vertices 431 and 432 of the gap expanding member 43 are in line contact with the first flat plate member 41A and the second flat plate member 41B are the deformation points of the link mechanism. This is because it can be positively formed at the apexes 431 and 432 of the interval expanding member 43.

  On the other hand, when bending the flat plate member 41 in advance, spring back variation occurs due to unevenness of the material, rolling directionality, etc., and it is difficult to create the same component (flat plate member). The dimensional accuracy tends to be unstable. Furthermore, when three-dimensional parts are joined together, assembly becomes extremely difficult, and variations in finished dimensions become very large. However, according to the manufacturing method shown in FIG. 28, since the joined body of flat plate members arranged in parallel is used, the dimensional stability is improved and the assembly can be easily performed. In addition, since the finished dimensions are stable, it is suitable as a small lens driving mechanism or the like.

  As described above, the embodiment of the drive mechanism (drive module S1) according to the second embodiment has been described. In the second embodiment, for example, the following modified embodiments (1) to (5) are adopted. Is also possible.

(1) Modified Embodiment 2-1: Application to Lens Drive Mechanism FIG. 30 (a) is a plan view showing a lens drive module S2 to which the drive mechanism according to the second embodiment is applied, and FIG. 30 (b). FIG. 3A is a side view in the direction of arrow R in FIG. The lens driving module S2 includes a lens unit 10A (driven object) disposed on the base member 510A and a driving device 400A that moves the lens unit 10A in the optical axis direction (Z-axis direction / first axis direction). It is comprised including.

  The driving device 400A includes two flat plate members 41 (first flat plate member 41A and second flat plate member 41B), two spacers 42, and two SMA actuators 430A and 430B, and the driving device 400 described in the above embodiment. And substantially the same configuration. The lens unit 10A has the photographing lens 100 as in the first embodiment, and also has a support 151, a first guide 152, a second guide 153, and a gap extending so as to protrude from its cylindrical outer peripheral wall. A member 43A is provided.

  The support portion 151 is engaged with the central portion 412A of the first flat plate member 41A that is the displacement output portion 400out. The first guide 152 has a hole through which the first guide rod 162 erected in the Z-axis direction from the base member 510A is inserted. Similarly, the second guide 153 has a guide recess that is in sliding contact with the second guide rod 163 that is erected from the base member 510 in the Z-axis direction. The interval enlarging member 43A corresponds to the interval enlarging member 43 in the above-described embodiment, and is a member that constitutes a part of the drive mechanism. In the present modified embodiment, the lens unit 10A is provided integrally. Here, the gap enlarging member 43A can be easily inserted between the two flat plate members 41 only by rotating the lens unit 10A around the optical axis, as shown in FIG. As shown in FIG.

  The driving device 400A is arranged along the vicinity of one side of the base member 510A in the Y-axis direction. A central portion 412B of the second flat plate member 41B is fixed to the base member 510A. The two SMA actuators 430A and 430B have electrodes 431 and 432 at their ends, and are respectively spanned by two spacers 42 so as to be folded at an acute angle.

  In such a configuration, when the SMA actuators 430A and 430B are energized and heated via the electrodes 431 and 432 and operate (shrink), the two spacers 42 serving as the displacement input unit 400in are moved by the moving forces F41 facing each other in the X-axis direction. F42 acts. The first flat plate member 41A and the second flat plate member 41B are elastically deformed by the moving forces F41 and F42, and the moving force in the optical axis (Z-axis) direction in which the amount of displacement is expanded at the central portion 412A of the first flat plate member 41A. F43 is generated.

  This moving force F43 is applied to the lens unit 10A via the support portion 151. At this time, since it is guided by the first guide rod 162 and the second guide rod 163, the lens unit 10A is moved only in the optical axis direction while being supported at one point by the support portion 151. On the other hand, when energization to the SMA actuators 430A and 430B is stopped, the lens unit 10A is returned to the original position by the bias spring force of the first flat plate member 41A and the second flat plate member 41B.

(2) Modified Embodiment 2-2: Other Installation Form of SMA Actuator FIG. 31 is a plan view showing a lens driving module S2 ′ according to a further modified embodiment of the modified embodiment 2-1. The difference from the modified embodiment 2-1 is the construction form of the SMA actuator. In this driving device 400B, the two SMA actuators 430C and 430D having the electrodes 433 and 434 at one end are not bridged around each spacer 42, but the SMA actuators 430C and 430D of each SMA actuator 42 are laid around each spacer 42. The other end is locked. In this case, the spacer 42 may be made of an electrode material and may be one electrode of the SMA actuators 430C and 430D.

(3) Modified embodiment 2-3: annular flat plate member FIG. 32A is a plan view showing a lens driving module S3 according to modified embodiment 2-3, and FIG. 32B is a main portion of FIG. FIG. The lens driving module S3 includes a lens unit 10B (driven object) disposed on the base member 510B and a driving device 400C that moves the lens unit 10B in the optical axis direction.

The drive device 400C of Modified Embodiment 2-3 includes two flat plate members 441 (first flat plate member 441A and second flat plate member 441B), two spacers 42, and two SMA actuators 430E and 430F. In the driving device 400C, two flat plate members 441 having a hexagonal shape in plan view are used. The shape of the flat plate member 441 may be a polygon other than a hexagon, an annular shape, an elliptical annular shape, or the like. Both the first flat plate member 441A and the second flat plate member 441B have a form in which six arm thin plates are connected so as to have a hexagonal internal space capable of accommodating the lens unit 10B. The hexagonal first flat plate member 441A and the second flat plate member 441B are integrally joined by the spacer 42 at the position of a pair of corner portions 442A and 442B on one first center line.

  The lens unit 10B is provided with two support portions 151A and 151B projecting from the outer peripheral wall at a position facing each other by 180 degrees. These support portions 151A and 151B are engaged with an arm piece 443A existing on a second center line orthogonal to the first center line of the first flat plate member 441A. On the other hand, the arm piece 443B of the second flat plate member 441B facing the arm piece 443A is fixed to the base member 510B. In the driving device 400C, the two spacers 42 serve as the displacement input unit 400in, and the two arm pieces 443A serve as the displacement output unit 400out.

  As shown in FIG. 32 (a), one SMA actuator 430E has an electrode 435 at the end, and is stretched over one spacer 42 so as to be bent at an obtuse angle so as to draw a "<" shape. ing. The other SMA actuator 430F has an electrode 436 at the end, and is stretched over the other spacer 42 so as to be bent at an obtuse angle so as to draw a “く” shape opposite to the SMA actuator 430E. Yes.

  In such a configuration, when the SMA actuators 430E and 430F are energized and heated through the electrodes 435 and 436 and operate (shrink), the moving forces F44 and F45 facing each other act on the two spacers 42. The first flat plate member 441A and the second flat plate member 441B are elastically deformed by the moving forces F44 and F45, and the two arm pieces 443A of the first flat plate member 41A are displaced in the optical axis (Z-axis) direction in which the displacement amount is increased. Movement force is generated. This moving force is applied to the lens unit 10B via the two support portions 151A and 151B, and the lens unit 10B is moved in the optical axis direction. On the other hand, when energization to the SMA actuators 430E and 430F is stopped, the lens unit 10B is returned to the original position by the bias spring force of the first flat plate member 441A and the second flat plate member 441B.

(4) Modified Embodiment 2-4; Other Installation Form of SMA Actuator FIG. 33 is a plan view showing a lens driving module S3 ′ according to a further modified embodiment of the modified embodiment 2-3. The difference from the modified embodiment 2-3 is the installation form of the SMA actuator. In this driving device 400D, one SMA actuator 430G having electrodes 437 at both ends is used.

  In order to enable installation with one SMA actuator 430G, a tension guide 438 is erected on the base member 510B. The tension guide 438 is erected in the vicinity of the corner of the base member 510B, and the SMA actuator 430G has one spacer 42, the tension guide 438, and the other starting from the diagonal corner where the tension guide 438 is disposed. The spacers 42 are looped around in order.

  In the driving device 400D of the modified embodiment 2-4, since one SMA actuator 430G contacts the two spacers 42, it is desirable that the two spacers 42 are electrically insulated. According to the driving device 400D, since the number of the electrodes 437 can be reduced, there is an advantage that the size can be easily reduced accordingly.

(5) Modified Embodiment 2-5: Improvement of Deformability of Flat Plate Member As described above, the shape of the link mechanism formed by the two flat plate members needs to be a substantially rhombus shape. The approximate rhombus may be an oval shape. However, in the case of an oval shape, the arc shape also changes with displacement, so that a conversion loss in the second axis direction of the moving force input in the first axis direction occurs. An efficient shape is a shape that deforms while maintaining a rhombus shape. In order to realize this, an easily deformable portion in which the rigidity of the portion corresponding to the deformation point of the link mechanism is made weaker than other portions may be formed on the flat plate member.

  FIG. 34A is a plan view showing an example of the easily deformable portion formed on the flat plate member 41. Here, an example is shown in which three long holes 451 that are long in the short-axis direction are provided at the center position in the long-axis direction of the rectangular flat plate member 41 and at both end positions inside the spacer 42. ing. By the perforation of the long hole 451, the width in the minor axis direction of the flat plate member 41 is substantially reduced. Therefore, the mechanical strength of the perforated portion of the long hole 451 is weaker than other portions.

  Therefore, as shown in FIGS. 34 (b) and 34 (c), when two flat plate members 41A and 41B with long holes 451 are joined by two spacers 42 to form one housing, the SMA actuator 30 When the is operated, the perforated portion of the long hole 451 is bent intensively. On the other hand, the portion other than the perforated portion of the long hole 451 has a lower bending level, so that it can be easily deformed while maintaining the rhombus shape. This makes it possible to achieve an efficient expansion of the displacement amount.

  The mode of the easily deformable portion is not limited to the punched portion. For example, as shown in FIG. 35, the width in the minor axis direction may be partially narrowed by punching out the side edge in the major axis direction of the flat plate member 41 to form the recess 452. FIG. 35 shows an example in which a concave portion 452 is provided at the center of the rectangular flat plate member 41 and a long hole 451 is provided at both ends, but the combination of both may be arbitrarily performed.

  FIG. 36 shows an example in which thin portions 453 each having a reduced thickness are formed on the flat plate members 41A and 41B. Such a thin portion 453 can be formed by etching the flat plate members 41A and 41B, for example.

It is a disassembled perspective view which shows the main structural members of the lens drive module S (imaging device) including the lens drive mechanism according to the first embodiment of the present invention. It is a top view of the lens drive mechanism 200 which concerns on 1st Embodiment of the top view. 3 is a side view of the lens driving mechanism 200. FIG. 3 is a plan view of the shape of a base member 51 as viewed from above. FIG. 4 is a plan view showing a shape of a top plate 52. FIG. It is a top view which shows the shape of the parallel leaf | plate spring 53 (the upper side leaf | plate spring 53a and the lower side leaf | plate spring 53b). It is a side view showing the state where SMA actuator 30 contracted by energization heating. It is the figure which extracts and shows the drive member 20 and the SMA actuator 30, (a) is the top view of a top view, (b) has shown the side view, respectively. (A), (b) is a schematic diagram which shows the relationship between the contraction displacement of the SMA actuator 30, and the displacement of the drive member 20. FIG. FIG. 4 is a schematic diagram for explaining a link mechanism of the drive member 20. (A)-(c) is a figure which shows typically the relationship between the said input displacement b and the output displacement c. 3 is a block diagram showing a control means 60 of the lens driving mechanism 200. FIG. It is a block diagram which shows the control means 60 'of the lens drive mechanism 200 which concerns on other embodiment. (A), (b) is a graph which shows the relationship between the displacement amount by a phase change, and resistance value. (A), (b) is an external appearance block diagram of the mobile phone 70 with a camera as an example of an imaging device. 4 is a block diagram showing a schematic electrical configuration of a camera-equipped mobile phone 70. FIG. It is a figure which shows the arrangement | positioning relationship between the drive member 20 which concerns on modification 1-1, and SMA actuator 30A, (a) is a top view, (b) shows a side view, respectively. It is a figure which shows the arrangement | positioning relationship between the drive member 20 which concerns on modification 1-2, and the SMA actuator 30B, (a) is a top view, (b) shows a side view, respectively. It is a figure which shows the arrangement | positioning relationship of the drive member 20 and SMA actuator 30C which concern on the other example of deformation | transformation embodiment 1-2, (a) is a top view, (b) shows a side view, respectively. It is a figure which shows the arrangement | positioning relationship between the drive member 20 which concerns on modification 1-3, and the two SMA actuators 30D and 30E, (a) is a top view, (b) shows a side view, respectively. It is a top view which shows the arrangement | positioning relationship of the drive member 20 and SMA actuator 30 which concern on deformation | transformation embodiment 1-4. It is a figure which shows the arrangement | positioning relationship of the drive member (1st drive piece 20A) which concerns on modification 1-5, and the SMA actuator 30, (a) is a top view, (b) shows a side view, respectively. It is a side view showing the arrangement relation of drive member 20 and SMA actuator 30 concerning modification 1-6. It is a figure which shows the arrangement | positioning relationship between the drive member 91 which concerns on modification 1-7, and the SMA actuator 30F, (a) is a top view, (b) is a partially broken side view, (c) is a cross section which shows operation | movement. Each figure is shown. It is a side view which shows drive module S1 to which the drive mechanism which concerns on 2nd Embodiment of this invention was applied. In FIG. 25, it is a side view which shows the state which the SMA actuator 430 contracted by the energization heating. It is a graph for demonstrating the property of a shape memory alloy. (A)-(c) is a side view which shows an example of the manufacturing method of the drive member which concerns on 2nd Embodiment. (A), (b) is a side view which shows the other example of a manufacturing method of a drive member. (A) is a top view which shows lens drive module S2 which concerns on modification 2-1 to which the drive mechanism which concerns on 2nd Embodiment is applied, (b) is a side view of the arrow R direction of (a). is there. It is a top view showing lens drive module S2 'concerning modification 2-2. (A) is a top view which shows lens drive module S3 which concerns on modification 2-3, FIG.32 (b) is a disassembled perspective view of the principal part of (a). It is a top view showing lens drive module S3 'concerning modification 2-4. (A)-(c) is explanatory drawing which shows an example of the easily deformable part formed in the flat plate member 41. FIG. It is explanatory drawing which shows the other example of an easily deformable part. It is explanatory drawing which shows the other example of an easily deformable part.

DESCRIPTION OF SYMBOLS 10, 10A, 10B Lens unit 11 Lens drive frame 12 Support part 14 Driven object 20 Drive member 20A 1st drive piece 20B 2nd drive piece 20in, 400in Displacement input part 20out, 400out Displacement output part 200 Lens drive mechanism 211 Guide piece (projecting part)
23, 26 Arm 23b Bent part (bent part)
30, 30A-F, 430 SMA actuator (shape memory alloy actuator)
31a First electrode (electrode for current heating)
31b Second electrode (electric heating electrode)
40 Image sensor 400 Drive device 41 Flat plate member 42 Spacer (interval holding member)
43 Spacing member 51 Base member 513 Tension guide 52 Top plate 53 Parallel leaf spring (regulating member)
54 Bias spring (biasing means)
60 Control Unit 61 Voltage Supply Circuit 62 Displacement Sensor 63 Lens Drive Control Unit 70 Mobile Phone with Camera (Imaging Device)
91 Drive member 911 Bent-shaped bent portion 912 Peripheral portion of cross-sectional shape AX Optical axis H Hollow portion

Claims (16)

A driving device for driving a driven object,
A displacement output unit that is movable in a predetermined first axis direction, and a displacement input unit that receives a movement force in a second axis direction orthogonal to the first axis and moves the displacement output unit in the first axis direction A drive member engaged with the driven object in the displacement output unit,
A linear shape memory alloy actuator that is disposed so as to be in contact with the drive member at least in the displacement input portion, and that applies the moving force to the displacement input portion ;
The drive member includes four arms linked in a quadrilateral shape so as to have a hollow portion capable of containing the driven object, and a bent portion, and two apex portions of the quadrilateral facing each other are The other two apex portions facing each other as the displacement input portion are used as the displacement output portion, and the bending portion is provided in the vicinity of the displacement input portion and the displacement output portion of the arm, whereby the displacement When the input unit and the displacement output unit are arranged at positions shifted in the first axial direction, and the displacement input unit receives an input of a moving force in the second axial direction, the displacement output unit A drive device that is moved in the first axial direction . Two of the drive members are used as a pair, and are combined such that the first axial directions are on the same axis, the displacement input part is coupled, and the displacement output part in one drive member is predetermined. When the displacement output portion of the other driving member is engaged with the driven object, the shape memory alloy actuator causes the displacement input portion to move in the second axial direction. When receiving the input of the moving force, the driven object engaged with the displacement output portion of the other driving member is displaced in the first axial direction with respect to the displacement output portion of the one driving member fixed. The drive device according to claim 1. A driving device for driving a driven object,
A displacement output unit that is movable in a predetermined first axis direction, and a displacement input unit that receives a movement force in a second axis direction orthogonal to the first axis and moves the displacement output unit in the first axis direction A drive member engaged with the driven object in the displacement output unit,
A linear shape memory alloy actuator that is disposed so as to be in contact with the drive member at least in the displacement input portion, and that applies the moving force to the displacement input portion;
The driving member, the four A over arm linked in a rectangular shape so as to provide a hollow portion capable of enclosing the driven object, a first driving piece formed by a bent portion, similar square A second drive piece having a link in the shape,
In the first drive piece, the two vertex portions of the quadrangle facing each other are used as the displacement input portion, and the other two vertex portions facing each other are the displacement output portion,
The second drive piece is fixed to a predetermined base member in which the two opposite vertex portions of the square are used as the displacement input portion, and the other two vertex portions facing each other are immobile. And
In both cases, the displacement input portion of the first drive piece and the displacement input portion of the second drive piece are coupled to each other, while the bends in the vicinity of the displacement input portion and the displacement output portion of the arm, respectively. by parts are provided, the first driving piece of the displacement output portion and said second driving piece of the fixed portion drive operated device you being disposed one behind the first axial direction and . Prior Symbol shape memory alloy actuator, in a plane including the displacement input portion provided on the two apex portion facing each other of the square, is suspended so as to surround the links of the rectangle, the only in these displacement input portion driving device according to any one of claims 1-3, characterized in that contact with the drive member. Each of the displacement input parts is provided with an erection part capable of guiding a wire,
Wherein the shape memory alloy actuator is composed of a single linear member having electrodes for electric heating to both ends of claim 4, characterized in that it bridged-installing portion of the displacement input portion Drive device. A tension guide for constructing the shape memory alloy actuator along the rectangular shape of the drive member is provided at a position on one side of the displacement output unit,
The shape memory alloy actuator is bridged so as to include a route returning from the position on the other side of the displacement output part to the base point side via the installation part of the displacement input part and the tension guide. The drive device according to claim 5 . The drive device according to claim 6 , wherein the shape memory alloy actuator is looped over or overlapped to be overlapped with the erection part of the displacement input part and the tension guide. . Each of the displacement input parts is provided with an erection part capable of guiding a wire,
The shape memory alloy actuator is composed of two linear bodies each provided with electrodes for energization heating at both ends,
It said shape each memory alloy actuator, in contact each bridging portion of the displacement input portion, the driving device according to claim 1 or 3, characterized in that it spans. A drive device according to claim 2 or 3 , wherein a plurality of the drive members are stacked in the first axial direction. A driving device for driving a driven object,
A displacement output unit that is movable in a predetermined first axis direction, and a displacement input unit that receives a movement force in a second axis direction orthogonal to the first axis and moves the displacement output unit in the first axis direction A drive member engaged with the driven object in the displacement output unit,
A linear shape memory alloy actuator that is disposed so as to be in contact with the drive member at least in the displacement input portion, and that applies the moving force to the displacement input portion;
The drive member has an annular shape into which the driven object can be inserted, the axial cross section thereof is a U-shape, and the bent portion of the U-shape has a shape positioned at the outermost portion in the radial direction,
The rather is that the bent portion of the shaped the displacement input portion, Ku-section drive operated device you characterized in that the peripheral portion is to the displacement output portions of the. A driving device for driving a driven object,
A displacement output unit that is movable in a predetermined first axis direction, and a displacement input unit that receives a movement force in a second axis direction orthogonal to the first axis and moves the displacement output unit in the first axis direction A drive member engaged with the driven object in the displacement output unit,
A linear shape memory alloy actuator that is disposed so as to be in contact with the drive member at least in the displacement input portion, and that applies the moving force to the displacement input portion;
The drive member is
Two flat plate members made of an elastic material;
The first plate has a first length in the first axial direction and is disposed at a predetermined distance between the two flat plate members. The two flat plate members are arranged in the first axial direction with the first length. Two spacing members that are joined in a substantially parallel state with a spacing of
The second axis has a second length longer than the first length in the first axial direction, and is disposed between the two flat plate members and between the two spacing members. and a distance enlargement member to expand the second length of the spacing between the spacing member in the flat plate members,
The two spacing members are between the displacement input portion, wherein the flat plate member, wherein the to that drive operated device that site spacing was expanded by the distance expansion member is to the displacement output portions of the. The two flat plate members have the same planar shape provided with a hollow portion capable of containing the driven object at the center thereof,
Drive device according to claim 1 1, wherein the two flat members at the two spacing members arranged across the hollow portion is joined. The flat plate member is substantially reduced in width in the minor axis direction at the center position in the major axis direction and both end positions inside the spacing member, or the thickness is reduced. drive device according to claim 1 1 or 12, characterized in that it has a deformable portion formed by. Using the driving device according to any one of claims 1 to 13,
The driven object is a lens unit;
The driving device, drive kinematic mechanism you and moving the lens unit in the optical axis direction. A lens unit;
And a driving device according to any one of claims 1 1 to 13, moving the lens unit in a predetermined optical axis direction,
The drive mechanism according to claim 1, wherein the distance increasing member is provided integrally with the lens unit. The drive mechanism according to claim 14 or 15 ,
An image sensor disposed on the image plane side of the lens unit;
Imaging apparatus characterized by a control means for controlling the operation of the drive mechanism.

Images