Imaging device, camera module, and control method of imaging device

Abstract

An imaging device (101) comprises a driving device (10) capable of driving a first wire (SA1) and a second wire (SA2). The driving device (10) performs a combination of: a first mode in which current flows from a first point (PT1) to a second point (PT2) on a first conductive path (CD1) and current flows from a second point (PT12) to a first point (PT11) on a second conductive path (CD2); and at least one of a second mode in which current flows only on the first conductive path (CD1) and a third mode in which current flows only on the second conductive path (CD2). A part that connects the first point (PT1) and the second point (PT2) and a part that connects the first point (PT11) and the second point (PT12) are provided parallel to each other. The first point (PT1) is provided side-by-side with the first point (PT11), and the second point (PT2) is provided side-by-side with the second point (PT12).

Description

Technical Field

[0001] The present disclosure relates to an imaging device, a camera module, and a method for controlling an imaging device.

Background Art

[0002] Conventionally, an imaging device using eight shape memory alloy wires has been known (see Patent Document 1). In this imaging device, the control circuit supplies current individually to each of the eight shape memory alloy wires using a PWM signal to heat and contract them, and moves a lens holder connected to the eight shape memory alloy wires.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described imaging device, the control circuit controls the drive circuit so that a conductive path for flowing a predetermined current through one of the eight shape memory alloy wires to be heated and a parallel-connected conductive path for dividing and flowing a predetermined current through the remaining seven of the eight shape memory alloy wires that are not to be heated are formed simultaneously. With this configuration, the control circuit can appropriately heat and contract a specific one of the shape memory alloy wires.

[0005] However, in the above-described imaging device, there is a possibility that a relatively large magnetic field (induced magnetic field) is formed around the conductive path for flowing current through one of the shape memory alloy wires to be heated. And that relatively large magnetic field becomes a noise source for the image sensor and may have an adverse effect on the image quality of the image sensor.

[0006] Therefore, it is desirable to provide an imaging device capable of reducing the magnitude of a magnetic field formed around a conductive path for supplying current to a shape memory alloy wire.

Means for Solving the Problem

[0007] An imaging device according to an embodiment of the present invention includes a fixed-side member including a fixed base, a movable-side member movable with respect to the fixed-side member, including a lens holder capable of holding a lens body so as to face an imaging element, a first shape memory alloy wire having one end fixed to the fixed-side member and the other end fixed to the movable-side member, a second shape memory alloy wire having one end fixed to the fixed-side member and the other end fixed to the movable-side member, a first conductive path provided on the fixed base and electrically connected to one end of the first shape memory alloy wire, a second conductive path provided on the fixed base and electrically connected to one end of the second shape memory alloy wire, a common conductive path electrically connected to each of the other ends of the first shape memory alloy wire and the second shape memory alloy wire, and a driving device configured to be electrically connected to each of the first conductive path, the second conductive path, and the common conductive path, and capable of supplying current to each of the first shape memory alloy wire and the second shape memory alloy wire to drive each of the first shape memory alloy wire and the second shape memory alloy wire. A portion connecting a first point and a second point on the first conductive path and a portion connecting the first point and the second point on the second conductive path are installed on the fixed base so as to be parallel to each other. The first point on the first conductive path is arranged in parallel with the first point on the second conductive path, and the second point on the first conductive path is arranged in parallel with the second point on the second conductive path. The driving device includes a first mode in which the first conductive path, the first shape memory alloy wire, the common conductive path, the second shape memory alloy wire, and the second conductive path are electrically connected in series to supply current to the first shape memory alloy wire and the second shape memory alloy wire so that current flows from the first point to the second point of the first conductive path and current flows from the second point to the first point of the second conductive path, a second mode in which the first conductive path, the first shape memory alloy wire, and the common conductive path are electrically connected in series to supply current to the first shape memory alloy wire so that current flows through the first conductive path, and a third mode in which the second conductive path, the second shape memory alloy wire, and the common conductive path are electrically connected in series to supply current to the second shape memory alloy wire so that current flows through the second conductive path, and is configured to be able to switch between them, and the first mode and,configured to execute in combination with at least one of the second mode and the third mode.

Advantages of the Invention

[0008] The above imaging device can reduce the magnitude of the magnetic field formed around the conductive path for supplying current to the shape memory alloy wire.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 5

Figure 6A

Figure 6B

Figure 7A

Figure 7B

Figure 7C

Figure 7D

Figure 7E

Figure 7F

Figure 8A

Figure 8B

Figure 9

Figure 10A

Figure 10B

Figure 10C

Figure 10D

Figure 11

Figure 12A

Figure 12B

Figure 13

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the imaging device 101 (lens actuator) according to the embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of the imaging device 101. FIG. 2 is an exploded perspective view of the imaging device 101.

[0011] In FIGS. 1 and 2, X1 represents one direction of the X-axis that constitutes a three-dimensional orthogonal coordinate system, and X2 represents the other direction of the X-axis. Also, Y1 represents one direction of the Y-axis that constitutes a three-dimensional orthogonal coordinate system, and Y2 represents the other direction of the Y-axis. Similarly, Z1 represents one direction of the Z-axis that constitutes a three-dimensional orthogonal coordinate system, and Z2 represents the other direction of the Z-axis. In FIGS. 1 and 2, the X1 side of the imaging device 101 corresponds to the front side (front face side) of the imaging device 101, and the X2 side of the imaging device 101 corresponds to the rear side (rear face side) of the imaging device 101. Also, the Y1 side of the imaging device 101 corresponds to the left side of the imaging device 101, and the Y2 side of the imaging device 101 corresponds to the right side of the imaging device 101. Also, the Z1 side of the imaging device 101 corresponds to the upper side (subject side) of the imaging device 101, and the Z2 side of the imaging device 101 corresponds to the lower side (imaging element side) of the imaging device 101. The same applies to other figures.

[0012] As shown in FIGS. 1 and 2, the imaging device 101 includes a cover member 4 that is a part of the fixed-side member FB.

[0013] The cover member 4 is configured to function as a housing that covers other members. In the present embodiment, the cover member 4 is formed of a non-magnetic metal. However, the cover member 4 may be formed of a magnetic metal. Also, as shown in FIG. 1, the cover member 4 defines a storage portion 4S.

[0014] The cover member 4 has a rectangular cylindrical outer peripheral wall portion 4A and a rectangular annular and flat top plate portion 4B provided so as to be continuous with the upper end (end on the Z1 side) of the outer peripheral wall portion 4A. A circular opening 4K is formed at the center of the top plate portion 4B. The outer peripheral wall portion 4A includes a first side plate portion 4A1 to a fourth side plate portion 4A4. The first side plate portion 4A1 and the third side plate portion 4A3 face each other, and the second side plate portion 4A2 and the fourth side plate portion 4A4 face each other. And the first side plate portion 4A1 and the third side plate portion 4A3 extend perpendicular to the second side plate portion 4A2 and the fourth side plate portion 4A4.

[0015] As shown in FIG. 2, a lens holder 2, a metal member 5, a leaf spring 6, a base member 18, a shape memory alloy wire SA, etc. are housed inside the cover member 4.

[0016] The movable-side member MB includes a lens holder 2 capable of holding a lens body (not shown) and a leaf spring 6 that supports the lens holder 2 so as to be movable along the optical axis OA. The lens body is, for example, a cylindrical lens barrel provided with at least one lens, and is configured such that its central axis extends along the optical axis OA.

[0017] The lens holder 2 is formed by injection molding a synthetic resin such as liquid crystal polymer (LCP). Specifically, as shown in FIG. 2, the lens holder 2 includes a cylindrical portion 2P formed to extend along the optical axis OA, and a movable-side pedestal portion 2D and a protruding portion 2S formed to protrude radially outward from the cylindrical portion 2P. In the present embodiment, the lens body is configured to be fixed to the inner peripheral surface of the cylindrical portion 2P with an adhesive.

[0018] The movable-side pedestal portion 2D includes a first movable-side pedestal portion 2D1 and a second movable-side pedestal portion 2D2. The first movable-side pedestal portion 2D1 and the second movable-side pedestal portion 2D2 are arranged so as to protrude in opposite directions across the optical axis OA. Similarly, the protruding portion 2S includes a first protruding portion 2S1 and a second protruding portion 2S2. The first protruding portion 2S1 and the second protruding portion 2S2 are arranged so as to protrude in opposite directions across the optical axis OA. Specifically, the movable-side pedestal portion 2D and the protruding portion 2S are arranged so as to correspond to the four corners of the lens holder 2 having a substantially rectangular outer shape in a top view, and are arranged so as to be alternately aligned. And, a part of the leaf spring 6 is placed on each of the two movable-side pedestal portions 2D.

[0019] The shape memory alloy wire SA is an example of a shape memory actuator. In this embodiment, the shape memory alloy wire SA includes first wires SA1 to eighth wires SA8. When an electric current flows through the shape memory alloy wire SA, its temperature rises, and it contracts in response to the rise in temperature. The imaging device 101 can move the lens holder 2 up and down along the optical axis OA by utilizing the contraction of the shape memory alloy wire SA. Note that in this embodiment, the shape memory alloy wire SA is configured such that when one or more of the first wires SA1 to eighth wires SA8 contract, the lens holder 2 moves, and one or more others are stretched by this movement.

[0020] The leaf spring 6 is configured to be electrically connected to the shape memory alloy wire SA through the metal member 5. In this embodiment, the leaf spring 6 is made of a metal plate mainly made of, for example, a copper alloy, a titanium copper-based alloy (titanium copper), or a copper nickel alloy (nickel silver copper). Specifically, the leaf spring 6 includes a first leaf spring 6A and a second leaf spring 6B.

[0021] The base member 18 (fixed base) is formed by injection molding using a synthetic resin such as liquid crystal polymer (LCP). In this embodiment, the base member 18 has a substantially rectangular outline in a top view and has an opening 18K at the center. Specifically, the base member 18 has four side portions 18E (first side portion 18E1 to fourth side portion 18E4) arranged to surround the opening 18K.

[0022] The leaf spring 6 is configured to connect the movable side pedestal portion 2D formed on the lens holder 2 and the fixed side pedestal portion 18D formed on the base member 18. Note that the fixed side pedestal portion 18D includes a first fixed side pedestal portion 18D1 and a second fixed side pedestal portion 18D2.

[0023] More specifically, the first leaf spring 6A is configured to connect the first movable-side pedestal portion 2D1 formed on the lens holder 2 to each of the first fixed-side pedestal portion 18D1 and the second fixed-side pedestal portion 18D2 formed on the base member 18. Similarly, the second leaf spring 6B is configured to connect the second movable-side pedestal portion 2D2 formed on the lens holder 2 to each of the first fixed-side pedestal portion 18D1 and the second fixed-side pedestal portion 18D2 formed on the base member 18.

[0024] The metal member 5 is configured such that the ends of the shape memory alloy wire SA are fixed thereto. In the present embodiment, the metal member 5 includes a fixed-side metal member 5F and a movable-side metal member 5M. The fixed-side metal member 5F forms a part of the fixed-side member FB and is configured to be fixed to the fixed-side pedestal portion 18D of the base member 18. The movable-side metal member 5M forms a part of the movable-side member MB and is configured to be fixed to the movable-side pedestal portion 2D of the lens holder 2.

[0025] More specifically, the fixed-side metal member 5F is also referred to as a fixed-side terminal plate and includes the first fixed-side terminal plate 5F1 to the eighth fixed-side terminal plate 5F8. The movable-side metal member 5M is also referred to as a movable-side terminal plate and includes the first movable-side terminal plate 5M1 to the fourth movable-side terminal plate 5M4.

[0026] Next, with reference to FIGS. 3A and 3B, the positional relationship between each of the lens holder 2 and the base member 18 and the metal member 5 will be described. FIG. 3A is a perspective view of the lens holder 2 to which the movable-side metal member 5M (movable-side terminal plate) and the leaf spring 6 are attached. FIG. 3B is a perspective view of the base member 18 to which the fixed-side metal member 5F (fixed-side terminal plate) is attached. For clarity, in FIG. 3A, the movable-side metal member 5M and the leaf spring 6 are provided with a dot pattern, and in FIG. 3B, the fixed-side metal member 5F is provided with a dot pattern.

[0027] In the example shown in FIG. 3A, the first movable-side terminal plate 5M1 is fixed to the side wall (right mounting surface) on the Y2 side of the first movable-side pedestal portion 2D1. Specifically, the first movable-side terminal plate 5M1 is fixed to the first movable-side pedestal portion 2D1 with an adhesive in a state where a rectangular protrusion 2V protruding outward (Y2 side) formed on the first movable-side pedestal portion 2D1 and a rectangular hole AH (see FIG. 4A) formed in the first movable-side terminal plate 5M1 are engaged with each other. The adhesive is, for example, a photocurable adhesive. The photocurable adhesive is, for example, an ultraviolet-curable adhesive or a visible-light-curable adhesive. Similarly, the second movable-side terminal plate 5M2 is fixed to the side wall (rear mounting surface) on the X2 side of the first movable-side pedestal portion 2D1, the third movable-side terminal plate 5M3 is fixed to the side wall (front mounting surface) on the X1 side of the second movable-side pedestal portion 2D2, and the fourth movable-side terminal plate 5M4 is fixed to the side wall (left mounting surface) on the Y1 side of the second movable-side pedestal portion 2D2.

[0028] In the example shown in FIG. 3B, the first fixed-side terminal plate 5F1 and the second fixed-side terminal plate 5F2 are fixed to the side wall (right mounting surface) on the Y2 side of the first fixed-side pedestal portion 18D1 arranged along the second side portion 18E2 of the base member 18. Specifically, the first fixed-side terminal plate 5F1 and the second fixed-side terminal plate 5F2 are fixed to the first fixed-side pedestal portion 18D1 with an adhesive. More specifically, the second fixed-side terminal plate 5F2 is fixed to the first fixed-side pedestal portion 18D1 with an adhesive in a state where the angular protrusion 18V protruding to the outside (Y2 side) formed on the first fixed-side pedestal portion 18D1 and the through hole RH (see FIG. 4A) formed on the second fixed-side terminal plate 5F2 are engaged with each other. The adhesive is, for example, a photocurable adhesive. The photocurable adhesive is, for example, an ultraviolet-curable adhesive or a visible-light-curable adhesive or the like. Similarly, the third fixed-side terminal plate 5F3 and the fourth fixed-side terminal plate 5F4 (invisible in FIG. 3B) are fixed to the side wall (rear mounting surface) on the X2 side of the second fixed-side pedestal portion 18D2 arranged along the third side portion 18E3 of the base member 18. Also, the fifth fixed-side terminal plate 5F5 and the sixth fixed-side terminal plate 5F6 are fixed to the side wall (front mounting surface) on the X1 side of the first fixed-side pedestal portion 18D1 arranged along the first side portion 18E1 of the base member 18. And the seventh fixed-side terminal plate 5F7 and the eighth fixed-side terminal plate 5F8 (invisible in FIG. 3B) are fixed to the side wall (left mounting surface) on the Y1 side of the second fixed-side pedestal portion 18D2 arranged along the fourth side portion 18E4 of the base member 18.

[0029] The shape memory alloy wire SA extends along the inner surface of the outer peripheral wall portion 4A of the cover member 4 and is configured to movably support the movable side member MB with respect to the fixed side member FB. In the present embodiment, the shape memory alloy wire SA includes first to eighth wires SA1 to SA8 and is configured to movably support the lens holder 2 as the movable side member MB with respect to the base member 18 as the fixed side member FB. As shown in FIG. 2, one end of each of the first to eighth wires SA1 to SA8 is fixed to the fixed side metal member 5F by crimping or welding or the like, and the other end is fixed to the movable side metal member 5M by crimping or welding or the like.

[0030] Next, with reference to FIGS. 4A and 4B, the metal member 5 to which the shape memory alloy wire SA is attached will be described. FIG. 4A is a view of the first wire SA1 attached to each of the first movable side terminal plate 5M1 and the first fixed side terminal plate 5F1, and the second wire SA2 attached to each of the first movable side terminal plate 5M1 and the second fixed side terminal plate 5F2 as viewed from the Y2 side. FIG. 4B is a view of the first wire SA1 attached to each of the first movable side terminal plate 5M1 and the first fixed side terminal plate 5F1, and the second wire SA2 attached to each of the first movable side terminal plate 5M1 and the second fixed side terminal plate 5F2 as viewed from the Z1 side. The positional relationship of each member shown in FIGS. 4A and 4B corresponds to the positional relationship when the imaging device 101 is assembled. In FIGS. 4A and 4B, for clarity, the illustration of other members is omitted. Further, the following description with reference to FIGS. 4A and 4B relates to the combination of the first wire SA1 and the second wire SA2, but the same applies to the combination of the third wire SA3 and the fourth wire SA4, the combination of the fifth wire SA5 and the sixth wire SA6, and the combination of the seventh wire SA7 and the eighth wire SA8.

[0031] Specifically, one end of the first wire SA1 is fixed to the first movable-side terminal plate 5M1 at the holding portion J3 below the first movable-side terminal plate 5M1, and the other end of the first wire SA1 is fixed to the first fixed-side terminal plate 5F1 at the holding portion J2 of the first fixed-side terminal plate 5F1. Similarly, one end of the second wire SA2 is fixed to the first movable-side terminal plate 5M1 at the holding portion J1 above the first movable-side terminal plate 5M1, and the other end of the second wire SA2 is fixed to the second fixed-side terminal plate 5F2 at the holding portion J4 of the second fixed-side terminal plate 5F2.

[0032] The holding portion J1 is formed by bending a part of the first movable-side terminal plate 5M1. Specifically, a part of the first movable-side terminal plate 5M1 is bent while sandwiching one end of the second wire SA2 to form the holding portion J1. And one end of the second wire SA2 is fixed to the holding portion J1 by welding. The same applies to the holding portions J2 to J4.

[0033] As shown in FIGS. 4A and 4B, the first wire SA1 and the second wire SA2 are arranged so as to be in a twisted position with respect to each other. That is, the first wire SA1 and the second wire SA2 are arranged so as not to contact each other (to be non-contact).

[0034] Next, referring to FIG. 5, the details of the base member 18, which is a part of the fixed-side member FB, will be described. FIG. 5 is a perspective view of the base member 18. Specifically, the upper view of FIG. 5 is a perspective view of the base member 18 with the conductive member CM removed, the central view of FIG. 5 is a perspective view of the conductive member CM embedded in the base member 18, and the lower view of FIG. 5 is a perspective view of the base member 18 with the conductive member CM embedded. In the central view and the lower view of FIG. 5, a dot pattern is attached to the conductive member CM for clarity.

[0035] The base member 18 is configured to function as a wire support member that supports one end of each of the first wire SA1 to the eighth wire SA8. With this configuration, the movable member MB is supported by the first wire SA1 to the eighth wire SA8 in a state where it can move in the Z-axis direction, which is a direction parallel to the optical axis OA.

[0036] On the upper surface, which is the surface on the subject side (the Z1 side surface) of the base member 18, a fixed-side pedestal portion 18D is formed. The fixed-side pedestal portion 18D includes a first fixed-side pedestal portion 18D1 and a second fixed-side pedestal portion 18D2. The first fixed-side pedestal portion 18D1 and the second fixed-side pedestal portion 18D2 are arranged to face each other with the optical axis OA interposed therebetween.

[0037] In the base member 18, a conductive member CM formed from a metal plate including a material such as copper, iron, or an alloy having these as main components, as shown in the central figure of FIG. 5, is embedded by insert molding. In the present embodiment, the conductive member CM is configured to have first terminal portions TM1 to TM6 that are exposed from the front surface (the X1 side surface) and the rear surface (the X2 side surface) of the base member 18 and extend downward (in the Z2 direction), and a fifth joint surface portion CP5 and a sixth joint surface portion CP6 that are exposed on the upper surface (the Z1 side surface) of the base member 18.

[0038] Specifically, the conductive member CM includes first conductive members CM1 to CM6. The first conductive member CM1 includes a first terminal portion TM1 and a first connection portion ED1. The second conductive member CM2 includes a second terminal portion TM2 and a second connection portion ED2. The third conductive member CM3 includes a third terminal portion TM3 and a third connection portion ED3. The fourth conductive member CM4 includes a fourth terminal portion TM4 and a fourth connection portion ED4. The fifth conductive member CM5 includes a fifth terminal portion TM5 and a fifth joint surface portion CP5. The sixth conductive member CM6 includes a sixth terminal portion TM6 and a sixth joint surface portion CP6.

[0039] The first terminal portion TM1, the second terminal portion TM2, and the sixth terminal portion TM6 are arranged along the third side portion 18E3 of the base member 18. The third terminal portion TM3 to the fifth terminal portion TM5 are arranged along the first side portion 18E1 of the base member 18.

[0040] And, the first connection portion ED1 of the first conductive member CM1 is arranged along the second side portion 18E2 of the base member 18, and the first terminal portion TM1 of the first conductive member CM1 is arranged along the third side portion 18E3, not the second side portion 18E2, of the base member 18. Similarly, the second connection portion ED2 of the second conductive member CM2 is arranged along the second side portion 18E2 of the base member 18, and the second terminal portion TM2 of the second conductive member CM2 is arranged along the third side portion 18E3, not the second side portion 18E2, of the base member 18.

[0041] Also, the third connection portion ED3 of the third conductive member CM3 is arranged along the fourth side portion 18E4 of the base member 18, and the third terminal portion TM3 of the third conductive member CM3 is arranged along the first side portion 18E1, not the fourth side portion 18E4, of the base member 18. Similarly, the fourth connection portion ED4 of the fourth conductive member CM4 is arranged along the fourth side portion 18E4 of the base member 18, and the fourth terminal portion TM4 of the fourth conductive member CM4 is arranged along the first side portion 18E1, not the fourth side portion 18E4, of the base member 18.

[0042] Thus, the first terminal portion TM1 to the sixth terminal portion TM6 are arranged along the first side portion 18E1 or the third side portion 18E3 of the base member 18, and are not arranged along the second side portion 18E2 and the fourth side portion 18E4 of the base member 18. This is to facilitate the mounting of the imaging device. Specifically, it is to enable a flexible printed circuit board or the like connected to the imaging device to be arranged passing under at least one of the second side portion 18E2 and the fourth side portion 18E4 of the base member 18.

[0043] Next, referring to FIGS. 6A and 6B, the positional relationship among the leaf spring 6, the shape memory alloy wire SA, the metal member 5, and the conductive member CM will be described. FIG. 6 is a diagram showing the positional relationship among the leaf spring 6, the shape memory alloy wire SA, the metal member 5, and the conductive member CM. Specifically, FIG. 6A is a perspective view of the metal member 5, the leaf spring 6, the shape memory alloy wire SA, and the conductive member CM, and FIG. 6B is a top view of the metal member 5 and the leaf spring 6. In FIG. 6B, for clarity, the illustration of the shape memory alloy wire SA and the conductive member CM is omitted. Also, in FIGS. 6A and 6B, for clarity, the leaf spring 6 is provided with a dot pattern.

[0044] As shown in FIG. 6B, the leaf spring 6 includes a first leaf spring 6A and a second leaf spring 6B. The first leaf spring 6A has a first portion 6A1 fixed to the first fixed-side pedestal portion 18D1 (see FIG. 2) of the base member 18, a second portion 6A2 fixed to the second fixed-side pedestal portion 18D2 (see FIG. 2) of the base member 18, a third portion 6A3 fixed to the first movable-side pedestal portion 2D1 (see FIG. 2) of the lens holder 2, a fourth portion 6A4 connecting the first portion 6A1 and the third portion 6A3, and a fifth portion 6A5 connecting the second portion 6A2 and the third portion 6A3.

[0045] In the first portion 6A1, a first through hole 6AH1 and a second through hole 6AH2 through which a round protrusion 18T (see FIG. 3B) protruding upward formed in the first fixed-side pedestal portion 18D1 is inserted are formed. In this embodiment, the fixing of the leaf spring 6 and the protrusion 18T is realized by applying thermal caulking or cold caulking to the protrusion 18T. However, the fixing of the leaf spring 6 and the protrusion 18T may also be realized by an adhesive.

[0046] In the second part 6A2, a third through-hole 6AH3 through which a round protruding portion 18T (see FIG. 3B) protruding upward formed on the second fixed-side pedestal portion 18D2 is inserted, and a fourth through-hole 6AH4 used for joining with the sixth joint surface portion CP6 (see the lower figure in FIG. 5) of the sixth conductive member CM6 are formed. In the present embodiment, the joining of the leaf spring 6 and the conductive member CM is realized by welding such as laser welding. However, the joining of the leaf spring 6 and the conductive member CM may be realized by solder or a conductive adhesive or the like.

[0047] In the third part 6A3, a fifth through-hole 6AH5 and a sixth through-hole 6AH6 through which a round protruding portion 2T (see FIG. 3A) protruding upward formed on the first movable-side pedestal portion 2D1 are inserted are formed. In the present embodiment, the fixing of the leaf spring 6 and the protruding portion 2T is realized by performing heat caulking or cold caulking on the protruding portion 2T. However, the fixing of the leaf spring 6 and the protruding portion 2T may be realized by an adhesive.

[0048] Similarly, the second leaf spring 6B has a first part 6B1 fixed to the first fixed-side pedestal portion 18D1 (see FIG. 2) of the base member 18, a second part 6B2 fixed to the second fixed-side pedestal portion 18D2 (see FIG. 2) of the base member 18, a third part 6B3 fixed to the second movable-side pedestal portion 2D2 (see FIG. 2) of the lens holder 2, a fourth part 6B4 connecting the first part 6B1 and the third part 6B3, and a fifth part 6B5 connecting the second part 6B2 and the third part 6B3.

[0049] In the first part 6B1, a first through-hole 6BH1 through which a round protruding portion 18T (see FIG. 3B) protruding upward formed on the first fixed-side pedestal portion 18D1 is inserted, and a second through-hole 6BH2 used for joining with the fifth joint surface portion CP5 (see the lower figure in FIG. 5) of the fifth conductive member CM5 are formed.

[0050] In the second part 6B2, a third through-hole 6BH3 and a fourth through-hole 6BH4 through which a round protruding portion 18T (see FIG. 3B) protruding upward formed on the second fixed-side pedestal portion 18D2 are inserted are formed.

[0051] In the third part 6B3, a fifth through-hole 6BH5 and a sixth through-hole 6BH6 are formed through which a round protruding portion 2T (see FIG. 3A) protruding upward formed on the second movable-side pedestal portion 2D2 is inserted.

[0052] The fourth and fifth portions 6A4 and 6A5 of the first leaf spring 6A and the fourth and fifth portions 6B4 and 6B5 of the second leaf spring 6B are elastic deformable arms having a plurality of bent portions. Therefore, the lens holder 2 can move not only in a direction parallel to the optical axis OA but also in a direction intersecting the optical axis OA with respect to the base member 18 (fixed-side member FB).

[0053] As shown in FIG. 6B, the first leaf spring 6A and the second leaf spring 6B have substantially the same shape. Specifically, the first leaf spring 6A and the second leaf spring 6B are configured to be rotationally symmetric about the optical axis OA twice. Therefore, this configuration can reduce the number of parts of the imaging device 101. In addition, the first leaf spring 6A and the second leaf spring 6B can support the lens holder 2 in a well-balanced manner in the air. Further, the leaf spring 6 does not adversely affect the weight balance of the movable-side member MB supported by eight shape memory alloy wires SA (first wire SA1 to eighth wire SA8).

[0054] As shown in FIG. 6A, the first connection portion ED1 of the first conductive member CM1 is joined to the first contact portion CT1 of the adjacent first fixed-side terminal plate 5F1 by a joining material SD. The joining material SD is, for example, solder or a conductive adhesive. Specifically, the first connection portion ED1 and the first contact portion CT1 are joined adjacent to each other with their surfaces substantially parallel. Similarly, the second connection portion ED2 of the second conductive member CM2 is joined to the second contact portion CT2 of the adjacent second fixed-side terminal plate 5F2 by the joining material SD, the third connection portion ED3 of the third conductive member CM3 is joined to the seventh contact portion CT7 of the adjacent seventh fixed-side terminal plate 5F7 by the joining material SD, and the fourth connection portion ED4 of the fourth conductive member CM4 is joined to the eighth contact portion CT8 of the adjacent eighth fixed-side terminal plate 5F8 by the joining material SD. In FIGS. 6A and 6B, for clarity, the joining material SD is represented by a dashed circle.

[0055] As shown in FIGS. 6A and 6B, the ninth contact portion CT9 of the first movable-side terminal plate 5M1 is vertically joined to the third portion 6A3 of the first leaf spring 6A by a bonding material SD. That is, the ninth contact portion CT9 and the third portion 6A3 are joined in a state where their surfaces are substantially perpendicular to each other. Similarly, the tenth contact portion CT10 of the second movable-side terminal plate 5M2 is vertically joined to the third portion 6A3 of the first leaf spring 6A by a bonding material SD, and the eleventh contact portion CT11 of the third movable-side terminal plate 5M3 is vertically joined to the third portion 6B3 of the second leaf spring 6B by a bonding material SD. The twelfth contact portion CT12 of the fourth movable-side terminal plate 5M4 is vertically joined to the third portion 6B3 of the second leaf spring 6B by a bonding material SD.

[0056] On the other hand, as shown in FIG. 6B, the first fixed-side terminal plate 5F1 is arranged separated from the first portion 6A1 of the first leaf spring 6A and does not contact the first portion 6A1 of the first leaf spring 6A. Similarly, the third fixed-side terminal plate 5F3 does not contact the second portion 6A2 of the first leaf spring 6A, the fifth fixed-side terminal plate 5F5 does not contact the first portion 6B1 of the second leaf spring 6B, and the seventh fixed-side terminal plate 5F7 does not contact the second portion 6B2 of the second leaf spring 6B.

[0057] The fifth joint surface portion CP5 of the fifth conductive member CM5 (see the central figure of FIG. 5) is joined in parallel to the first portion 6B1 of the second leaf spring 6B by welding such as laser welding at the second through hole 6BH2 formed in the first portion 6B1 of the second leaf spring 6B. That is, the fifth joint surface portion CP5 and the first portion 6B1 are joined in a state where their surfaces are substantially parallel to each other. Similarly, the sixth joint surface portion CP6 of the sixth conductive member CM6 (see the central figure of FIG. 5) is joined in parallel to the second portion 6A2 of the first leaf spring 6A by welding such as laser welding at the fourth through hole 6AH4 formed in the second portion 6A2 of the first leaf spring 6A.

[0058] Next, with reference to FIGS. 7A to 7F, the path of the current flowing through the shape memory alloy wire SA will be described. FIGS. 7A to 7F are diagrams of a part of the configuration shown in FIG. 6A. In FIGS. 7A to 7F, for clarity, a dot pattern is attached to the members through which the current flows. Specifically, in FIG. 7A, a thick dot pattern is attached to the first conductive member CM1 and the second conductive member CM2, and a fine dot pattern is attached to the first movable-side terminal plate 5M1, the first fixed-side terminal plate 5F1, and the second fixed-side terminal plate 5F2. Also, in FIG. 7B, a thick dot pattern is attached to the first conductive member CM1 and the sixth conductive member CM6, a fine dot pattern is attached to the first leaf spring 6A, and an even finer dot pattern is attached to the first movable-side terminal plate 5M1 and the first fixed-side terminal plate 5F1. Also, in FIG. 7C, a thick dot pattern is attached to the second conductive member CM2 and the sixth conductive member CM6, a fine dot pattern is attached to the first leaf spring 6A, and an even finer dot pattern is attached to the first movable-side terminal plate 5M1 and the second fixed-side terminal plate 5F2. Also, in FIG. 7D, a fine dot pattern is attached to the second movable-side terminal plate 5M2, the third fixed-side terminal plate 5F3, and the fourth fixed-side terminal plate 5F4. Also, in FIG. 7E, a thick dot pattern is attached to the sixth conductive member CM6, a fine dot pattern is attached to the first leaf spring 6A, and an even finer dot pattern is attached to the second movable-side terminal plate 5M2 and the third fixed-side terminal plate 5F3. Also, in FIG. 7F, a thick dot pattern is attached to the sixth conductive member CM6, a fine dot pattern is attached to the first leaf spring 6A, and an even finer dot pattern is attached to the second movable-side terminal plate 5M2 and the fourth fixed-side terminal plate 5F4.

[0059] Specifically, FIG. 7A shows the current path when the first terminal portion TM1 of the first conductive member CM1 is connected to a high potential and the second terminal portion TM2 of the second conductive member CM2 is connected to a low potential. FIG. 7B shows the current path when the first terminal portion TM1 of the first conductive member CM1 is connected to a high potential and the sixth terminal portion TM6 of the sixth conductive member CM6 is connected to a low potential. FIG. 7C shows the current path when the second terminal portion TM2 of the second conductive member CM2 is connected to a high potential and the sixth terminal portion TM6 of the sixth conductive member CM6 is connected to a low potential. The following description with reference to FIGS. 7A to 7C relates to the current path flowing through the first wire SA1 or the second wire SA2, but is similarly applicable to the current path flowing through the seventh wire SA7 or the eighth wire SA8.

[0060] When the first terminal portion TM1 of the first conductive member CM1 is connected to a high potential and the second terminal portion TM2 of the second conductive member CM2 is connected to a low potential, the current flows from the first terminal portion TM1 through the first conductive member CM1 to the first fixed-side terminal plate 5F1 as shown by the arrow AR1 in FIG. 7A. Thereafter, the current passes through the first fixed-side terminal plate 5F1 as shown by the arrow AR2, passes through the first wire SA1 as shown by the arrow AR3, and further passes through the first movable-side terminal plate 5M1 as shown by the arrow AR4. Thereafter, the current passes through the second wire SA2 as shown by the arrow AR5, passes through the second fixed-side terminal plate 5F2 as shown by the arrow AR6, and then flows through the second conductive member CM2 to the second terminal portion TM2 as shown by the arrow AR7.

[0061] When the first terminal portion TM1 of the first conductive member CM1 is connected to a high potential and the sixth terminal portion TM6 of the sixth conductive member CM6 is connected to a low potential, current flows from the first terminal portion TM1 through the first conductive member CM1 to the first fixed-side terminal plate 5F1 as indicated by arrow AR11 in FIG. 7B. Thereafter, the current passes through the first fixed-side terminal plate 5F1 as indicated by arrow AR12, passes through the first wire SA1 as indicated by arrow AR13, and further passes through the first movable-side terminal plate 5M1 as indicated by arrow AR14. Thereafter, the current passes through the third portion 6A3, the fifth portion 6A5, and the second portion 6A2 of the first leaf spring 6A as indicated by arrow AR15, and then flows through the sixth conductive member CM6 as indicated by arrows AR16 and AR17 to the sixth terminal portion TM6.

[0062] When the second terminal portion TM2 of the second conductive member CM2 is connected to a high potential and the sixth terminal portion TM6 of the sixth conductive member CM6 is connected to a low potential, current flows from the second terminal portion TM2 through the second conductive member CM2 to the second fixed-side terminal plate 5F2 as indicated by arrow AR21 in FIG. 7C. Thereafter, the current passes through the second fixed-side terminal plate 5F2 as indicated by arrow AR22, passes through the second wire SA2 as indicated by arrow AR23, and further passes through the first movable-side terminal plate 5M1 as indicated by arrow AR24. Thereafter, the current passes through the third portion 6A3, the fifth portion 6A5, and the second portion 6A2 of the first leaf spring 6A as indicated by arrow AR25, and then flows through the sixth conductive member CM6 as indicated by arrows AR26 and AR27 to the sixth terminal portion TM6.

[0063] Further, FIG. 7D shows the current path when the third contact portion CT3 of the third fixed-side terminal plate 5F3 is connected to a high potential and the fourth contact portion CT4 of the fourth fixed-side terminal plate 5F4 is connected to a low potential. FIG. 7E shows the current path when the third contact portion CT3 of the third fixed-side terminal plate 5F3 is connected to a high potential and the sixth terminal portion TM6 of the sixth conductive member CM6 is connected to a low potential. FIG. 7F shows the current path when the fourth contact portion CT4 of the fourth fixed-side terminal plate 5F4 is connected to a high potential and the sixth terminal portion TM6 of the sixth conductive member CM6 is connected to a low potential. The following description with reference to FIGS. 7D to 7F relates to the current path flowing through the third wire SA3 or the fourth wire SA4, but is similarly applicable to the current path flowing through the fifth wire SA5 or the sixth wire SA6.

[0064] When the third contact portion CT3 of the third fixed-side terminal plate 5F3 is connected to a high potential and the fourth contact portion CT4 of the fourth fixed-side terminal plate 5F4 is connected to a low potential, the current flows from the third contact portion CT3 through the third fixed-side terminal plate 5F3 to the third wire SA3 as indicated by the arrow AR31 in FIG. 7D. Thereafter, the current passes through the third wire SA3 as indicated by the arrow AR32, passes through the second movable-side terminal plate 5M2 as indicated by the arrow AR33, and further passes through the fourth wire SA4 as indicated by the arrow AR34. Thereafter, the current flows through the fourth fixed-side terminal plate 5F4 to the fourth contact portion CT4 as indicated by the arrow AR35.

[0065] When the third contact portion CT3 of the third fixed-side terminal plate 5F3 is connected to a high potential and the sixth terminal portion TM6 of the sixth conductive member CM6 is connected to a low potential, current flows from the third contact portion CT3 to the third wire SA3 through the third fixed-side terminal plate 5F3 as indicated by the arrow AR41 in FIG. 7E. Thereafter, the current passes through the third wire SA3 as indicated by the arrow AR42, passes through the second movable-side terminal plate 5M2 as indicated by the arrow AR43, and further passes through the third portion 6A3, the fifth portion 6A5, and the second portion 6A2 of the first leaf spring 6A as indicated by the arrow AR44. Thereafter, the current flows from the sixth joint surface portion CP6 to the sixth terminal portion TM6 through the sixth conductive member CM6 as indicated by the arrow AR45.

[0066] When the fourth contact portion CT4 of the fourth fixed-side terminal plate 5F4 is connected to a high potential and the sixth terminal portion TM6 of the sixth conductive member CM6 is connected to a low potential, current flows from the fourth contact portion CT4 to the fourth wire SA4 through the fourth fixed-side terminal plate 5F4 as indicated by the arrow AR51 in FIG. 7F. Thereafter, the current passes through the fourth wire SA4 as indicated by the arrow AR52, passes through the second movable-side terminal plate 5M2 as indicated by the arrow AR53, and further passes through the third portion 6A3, the fifth portion 6A5, and the second portion 6A2 of the first leaf spring 6A as indicated by the arrow AR54. Thereafter, the current flows from the sixth joint surface portion CP6 to the sixth terminal portion TM6 through the sixth conductive member CM6 as indicated by the arrow AR55.

[0067] Next, with reference to FIGS. 8A and 8B, an example of a connection structure for connecting the fixed-side metal member 5F and the conductive member CM will be described. FIGS. 8A and 8B are diagrams showing an example of a connection structure for connecting the fixed-side metal member 5F and the conductive member CM. Specifically, FIG. 8A is an enlarged view (perspective view) of the range R1 surrounded by the broken line shown in FIG. 3B. FIG. 8B is a right side view of the range R1 surrounded by the broken line shown in FIG. 3B. In FIGS. 8A and 8B, for clarity, the base member 18 is provided with a fine dot pattern.

[0068] As shown in FIGS. 8A and 8B, the first fixed-side terminal plate 5F1 is attached to the side wall (right attachment surface) on the Y2 side of the first fixed-side pedestal portion 18D1 of the base member 18 by a photocurable adhesive. And the first contact portion CT1 of the first fixed-side terminal plate 5F1 is joined to the first connection portion ED1 of the first conductive member CM1 via the bonding material SD. In FIGS. 8A and 8B, for clarity, a cross pattern is given to the bonding material SD.

[0069] Similarly, the second fixed-side terminal plate 5F2 is attached to the side wall (right attachment surface) on the Y2 side of the first fixed-side pedestal portion 18D1 of the base member 18 by a photocurable adhesive. And the second contact portion CT2 of the second fixed-side terminal plate 5F2 is joined to the second connection portion ED2 of the second conductive member CM2 via the bonding material SD.

[0070] As shown in FIG. 8B, the first connection portion ED1 is arranged in the X-axis direction such that the end face on the X1 side (front side) faces the end face on the X2 side (rear side) of the first contact portion CT1. Similarly, the second connection portion ED2 is arranged in the X-axis direction such that the end face on the X1 side (front side) faces the end face on the X2 side (rear side) of the second contact portion CT2.

[0071] This arrangement enables the bonding material SD to adhere to at least the front face (the face on the X1 side) of the first connection portion ED1, the rear face (the face on the X2 side) and the upper face (the face on the Z1 side) of the first contact portion CT1, thereby enhancing the connection strength of the bonding material SD between the first contact portion CT1 and the first connection portion ED1. The same applies to the connection strength of the bonding material SD between the second contact portion CT2 and the second connection portion ED2.

[0072] Also, this arrangement can prevent only the right end face (the face on the Y2 side) of the first connection part ED1 without plating from being joined to the first contact part CT1 by the joining material SD. The same applies to the joining between the second connection part ED2 and the second contact part CT2. Note that the right end face (the face on the Y2 side) of the first connection part ED1 is a cut surface formed when separating a cut-off connection part (not shown), and thus is not plated. The cut-off connection part is a part for connecting a plurality of conductive members, and is used when the plurality of conductive members are embedded in the base member 18 by insert molding but is finally cut off.

[0073] Next, referring to FIG. 9, the drive device 10 and the control device 20, which are components of the imaging device 101 as described above, will be described. FIG. 9 is a diagram showing a configuration example of the drive device 10 and the control device 20. In FIG. 9, for clarity, the parts constituting the drive device 10 are represented by solid lines, and the parts constituting the control device 20 are represented by broken lines.

[0074] The drive device 10 is configured to be able to supply a drive current to each of a plurality of shape memory alloy wires SA to drive each of the plurality of shape memory alloy wires SA. The drive current is a current for driving (heating and contracting) the shape memory alloy wire SA, and is, for example, a pulse current. In the present embodiment, the drive device 10 is an electronic circuit composed of active elements AE such as switching elements, operational amplifiers, or ICs, and is configured to operate according to a control signal from the control device 20.

[0075] In the illustrated example, the drive device 10 includes a first drive device 10A configured to be able to drive each of the first wire SA1 to the fourth wire SA4, and a second drive device 10B (details not shown) configured to be able to drive each of the fifth wire SA5 to the eighth wire SA8. The second drive device 10B has the same configuration as the first drive device 10A.

[0076] The control device 20 is configured to be able to control the drive device 10. In the present embodiment, the control device 20 is a microcomputer including a CPU, a volatile memory device, a non-volatile memory device, and the like.

[0077] In the illustrated example, the control device 20 can control the drive device 10 to move the lens holder 2 along a direction parallel to the optical axis OA by using the driving force along the direction parallel to the optical axis OA due to the contraction of the shape memory alloy wire SA on the Z1 side (subject side) of the imaging element. And by moving the lens holder 2 in this way, the control device 20 can realize an autofocus adjustment function which is one of the lens adjustment functions. Specifically, the control device 20 can move the lens holder 2 in a direction away from the imaging element to realize macro shooting, and can move the lens holder 2 in a direction approaching the imaging element to realize infinity shooting.

[0078] Also, the control device 20 can control the drive device 10 to move the lens holder 2 in a direction intersecting the optical axis OA by controlling the current flowing through the plurality of shape memory alloy wires SA. Thereby, the control device 20 can realize a shake correction function.

[0079] Note that in the illustrated example, the imaging device 101 having a substantially rectangular parallelepiped shape is mounted on an external substrate (not shown) on which an imaging element (not shown) is mounted. And the camera module is composed of, for example, an external substrate, the imaging device 101, a lens body mounted on the lens holder 2, and an imaging element arranged to face the lens body. Also, the drive device 10 and the control device 20 are mounted on the external substrate. However, at least one of the drive device 10 and the control device 20 may be arranged inside the imaging device 101. Also, the imaging element may be mounted on the imaging device 101.

[0080] Also, in the illustrated example, the control device 20 can control the drive device 10 so that a measurement current is supplied to each of the eight shape memory alloy wires SA at a timing different from the timing when the drive current is supplied.

[0081] The measurement current is a current for measuring the resistance between both ends of the shape memory alloy wire SA. The measurement current is desirably a weak current that does not affect the length of the shape memory alloy wire SA, for example, a pulse current. In the illustrated example, the control device 20 can derive the magnitude of the resistance (measurement resistance value) between both ends of the shape memory alloy wire SA by measuring the voltage between both ends of the shape memory alloy wire SA when a measurement current having a known magnitude is passed through the shape memory alloy wire SA. Then, the measurement resistance value of each of the eight shape memory alloy wires SA is used to realize a desired posture of the lens holder 2 (lens body). For example, the control device 20 can set the target length of each of the eight shape memory alloy wires SA corresponding to the desired posture of the lens holder 2 (lens body), and further can set the target resistance value of each of the eight shape memory alloy wires SA corresponding to each of those eight target lengths. Then, the control device 20 can realize the desired posture of the lens holder 2 (lens body) by controlling the drive device 10 so that the difference between the measurement resistance value and the target resistance value of each of the eight shape memory alloy wires SA approaches zero. Note that since the measurement current is a weak current that does not affect the length of the shape memory alloy wire SA, its magnitude is significantly smaller than the magnitude of the drive current.

[0082] In the illustrated example, the control device 20 sets a target resistance value for each of the eight shape memory alloy wires SA to realize a desired posture of the lens holder 2 (lens body). Then, the control device 20 controls the drive device 10 so that the measurement resistance value of each of the eight shape memory alloy wires SA becomes the same as the target resistance value. That is, the control device 20 executes feedback control of the resistance value of each of the eight shape memory alloy wires SA.

[0083] Specifically, for each of the eight shape memory alloy wires SA, the control device 20 controls the drive device 10 so that the difference between the target resistance value and the measured resistance value approaches zero, and adjusts at least one of the magnitude and supply time (duration) of the drive current supplied to each of the eight shape memory alloy wires SA. In the illustrated example, when the target resistance value of a specific shape memory alloy wire SA is smaller than the measured resistance value, the control device 20 increases the amount of electric power supplied to that specific shape memory alloy wire SA in order to contract that specific shape memory alloy wire SA. For example, the control device 20 increases the supply time of the drive current, that is, the time during which a predetermined voltage is applied across both ends of that specific shape memory alloy wire SA. Conversely, when the target resistance value of a specific shape memory alloy wire SA is larger than the measured resistance value, the control device 20 reduces the amount of electric power supplied to that specific shape memory alloy wire SA in order to extend that specific shape memory alloy wire SA, and then increases the amount of electric power supplied to another shape memory alloy wire SA other than that specific shape memory alloy wire SA. For example, the control device 20 increases the time during which a predetermined voltage is applied across both ends of another shape memory alloy wire SA other than that specific shape memory alloy wire SA.

[0084] Specifically, as shown in FIG. 9, the first drive device 10A includes a high potential source 11, a low potential source 12, a constant current source 13, and an active element AE. The following description with reference to FIG. 9 pertains to the first drive device 10A, but is equally applicable to the second drive device 10B.

[0085] The high potential source 11 is a potential source configured to have a potential higher than the potential of each of the ground (GND) and the low potential source 12.

[0086] The low potential source 12 is a potential source configured to have a potential higher than the potential of the ground (GND) and lower than the high potential source 11.

[0087] Note that although the high potential source 11 and the low potential source 12 both have fixed potentials, at least one of the high potential source 11 and the low potential source 12 may be configured to have its potential dynamically changed in response to a control signal from the control device 20.

[0088] The constant current source 13 is an electric circuit that can pass a current having a constant magnitude even when the resistance value of the load changes. In the illustrated example, the constant current source 13 is configured to be able to pass a measurement current having a constant magnitude through each of the first wire SA1 to the fourth wire SA4. The magnitude of the measurement current is set by, for example, the control device 20. In this case, the magnitude of the measurement current may be stored in a non-volatile storage device in the control device 20. For example, the magnitude of the measurement current may be set based on the result of an inspection at a factory performed at the time of shipment of the product (imaging device 101) so as to be suitable for each of the first wire SA1 to the fourth wire SA4. In this case, variations in characteristics due to individual differences in the shape memory alloy wires are suppressed.

[0089] The active element AE is an element that performs an active operation such as amplification or rectification with the supplied power. In the illustrated example, the active element AE includes the first active element AE1 to the sixth active element AE6.

[0090] The first active element AE1 is a multiplexer that integrates three inputs into one output. In the illustrated example, the three inputs of the first active element AE1 are connected to the high potential source 11, the low potential source 12, and the constant current source 13, and one output of the first active element AE1 is connected to the second active element AE2.

[0091] The second active element AE2 is a demultiplexer that distributes one input to four outputs. In the illustrated example, one input of the second active element AE2 is connected to the first active element AE1, and the four outputs of the second active element AE2 are connected to the first wire SA1, the third wire SA3, the third active element AE3, and the fourth active element AE4.

[0092] The third active element AE3 is a multiplexer that integrates two inputs into one output. In the illustrated example, the two inputs of the third active element AE3 are connected to the second active element AE2 and the ground (GND), and one output of the third active element AE3 is connected to the second wire SA2.

[0093] The fourth active element AE4 is a multiplexer that integrates two inputs into one output. In the illustrated example, the two inputs of the fourth active element AE4 are connected to the second active element AE2 and the ground (GND), and one output of the fourth active element AE4 is connected to the fourth wire SA4.

[0094] The fifth active element AE5 is a switching element that controls the connection between the input and the output. In the illustrated example, the input of the fifth active element AE5 is connected to a common conduction path CD0, which is a conduction path connected to each of the first wire SA1, the second wire SA2, the third wire SA3, and the fourth wire SA4, and one output of the fifth active element AE5 is connected to the ground (GND).

[0095] The sixth active element AE6 is an operational amplifier (op-amp) having two inputs and one output. In the illustrated example, one input of the sixth active element AE6 is connected to the first measurement point MP1 on the conduction path between the first active element AE1 and the second active element AE2, the other input of the sixth active element AE6 is connected to the second measurement point MP2 on the common conduction path CD0, and one output of the sixth active element AE6 is connected to the control device 20.

[0096] Note that in the illustrated example, one end of the first wire SA1 is connected to the second active element AE2 through the first conductive path CD1, and the other end is connected to the common conductive path CD0. Also, one end of the second wire SA2 is connected to the third active element AE3 through the second conductive path CD2, and the other end is connected to the common conductive path CD0. Further, one end of the third wire SA3 is connected to the second active element AE2 through the third conductive path CD3, and the other end is connected to the common conductive path CD0. Moreover, one end of the fourth wire SA4 is connected to the fourth active element AE4 through the fourth conductive path CD4, and the other end is connected to the common conductive path CD0.

[0097] Specifically, as shown in FIG. 7A, the first conductive path CD1 includes the first fixed-side terminal plate 5F1, and the second conductive path CD2 includes the second fixed-side terminal plate 5F2. Also, as shown in FIG. 7D, the third conductive path CD3 includes the third fixed-side terminal plate 5F3, and the fourth conductive path CD4 includes the fourth fixed-side terminal plate 5F4. Further, as shown in FIGS. 7B, 7C, 7E, and 7F, the common conductive path CD0 includes the first movable-side terminal plate 5M1, the second movable-side terminal plate 5M2, the first leaf spring 6A (the third portion 6A3, the fifth portion 6A5, and the second portion 6A2), and the sixth conductive member CM6.

[0098] That is, as shown in FIGS. 7A to 7F, the first driving device 10A can control the contraction of each of the first wire SA1 to the fourth wire SA4 by controlling the voltage applied to each of the first terminal portion TM1, the second terminal portion TM2, the sixth terminal portion TM6, the third contact portion CT3, and the fourth contact portion CT4. The same applies to the second driving device 10B.

[0099] Also, in the illustrated example, when the first driving device 10A passes current through each of the third wire SA3 and the fourth wire SA4, it does not use long conductive paths (the first conductive member CM1 and the second conductive member CM2 extending along the opening 18K of the base member 18) such as those used when passing current through each of the first wire SA1 and the second wire SA2. Therefore, this configuration has the effect of reducing the magnetic field (induced magnetic field) formed around the conductive path, which may have an adverse effect on the image quality of the imaging device, when passing current through each of the third wire SA3 and the fourth wire SA4. In other words, this configuration has the effect of relaxing the restrictions on the magnitude of the current flowing through each of the third wire SA3 and the fourth wire SA4 compared to the restrictions on the magnitude of the current flowing through each of the first wire SA1 and the second wire SA2.

[0100] Also, in the illustrated example, the first driving device 10A and the second driving device 10B are configured to share each of the high-potential source 11, the low-potential source 12, and the constant-current source 13, but may be configured to individually include at least one of the high-potential source 11, the low-potential source 12, and the constant-current source 13. For example, the constant-current source 13 may include a first constant-current source connected to the first active element AE1 of the first driving device 10A and a second constant-current source connected to the first active element (not shown) of the second driving device 10B.

[0101] Also, in the illustrated example, the driving device 10 is configured to be connected to each of the high-potential source 11 and the low-potential source 12, but may be configured to be connected to only one of the high-potential source 11 and the low-potential source 12. In this case, the other of the high-potential source 11 and the low-potential source 12 may be omitted.

[0102] Also, in the illustrated example, the drive device 10 has a constant current source 13 and is configured to electrically connect the constant current source 13 and the shape memory alloy wire SA when passing a measurement current through the shape memory alloy wire SA. However, the constant current source 13 may be omitted. In this case, the drive device 10 may include an AD converter for detecting the magnitude of the measurement current flowing through the shape memory alloy wire SA as a voltage value. Alternatively, the drive device 10 may include a shunt resistor for measuring the magnitude of the measurement current flowing through the shape memory alloy wire SA.

[0103] Also, in the illustrated example, the common conduction path CD0 is configured to be connected to the ground (GND) via the fifth active element AE5, but may be configured to be connected to one of the high potential source 11 and the low potential source 12 via an active element. In this case, each of the first wire SA1 to the fourth wire SA4 may be configured such that one end is connected to the ground (GND) via an active element such as an N-channel type transistor, and the other end is connected to the common conduction path CD0.

[0104] Next, with reference to FIGS. 10A to 10D, an example of the current path flowing through the shape memory alloy wire SA will be described. FIGS. 10A to 10D are diagrams showing examples of current paths in the drive device 10 and correspond to FIG. 9. In FIGS. 10A to 10D, for clarity, the conduction paths through which current is flowing are represented by thick solid lines, and the conduction paths through which no current is flowing are represented by broken lines.

[0105] FIG. 10A shows an example of a path of a driving current flowing through two shape memory alloy wires SA (first wire SA1 and second wire SA2) electrically connected in series. The path of the driving current shown in FIG. 7A is one of the specific examples of the path of the driving current shown in FIG. 10A. Specifically, FIG. 10A shows the path of the driving current flowing from the high potential source 11 to the ground (GND) when the high potential source 11, the first conductive path CD1, the first wire SA1, the common conductive path CD0, the second wire SA2, the second conductive path CD2, and the ground (GND) are electrically connected in series. In this case, the first conductive path CD1 is realized by the first conductive member CM1 and the first fixed-side terminal plate 5F1 in FIG. 7A, the second conductive path CD2 is realized by the second fixed-side terminal plate 5F2 and the second conductive member CM2 in FIG. 7A, and the common conductive path CD0 is realized by the first movable-side terminal plate 5M1.

[0106] FIG. 10B shows an example of a path of a driving current flowing through one shape memory alloy wire SA (first wire SA1). The path of the driving current shown in FIG. 7B is one of the specific examples of the path of the driving current shown in FIG. 10B. Specifically, FIG. 10B shows the path of the driving current flowing from the low potential source 12 to the ground (GND) when the low potential source 12, the first conductive path CD1, the first wire SA1, the common conductive path CD0, and the ground (GND) are electrically connected in series. In this case, the first conductive path CD1 is realized by the first conductive member CM1 and the first fixed-side terminal plate 5F1 in FIG. 7B, and the common conductive path CD0 is realized by the first movable-side terminal plate 5M1, the first leaf spring 6A (third portion 6A3, fifth portion 6A5, and second portion 6A2), and the sixth conductive member CM6 in FIG. 7B.

[0107] FIG. 10C shows another example of the path of the driving current flowing through one shape memory alloy wire SA (second wire SA2). The path of the driving current shown in FIG. 7C is one of the specific examples of the path of the driving current shown in FIG. 10C. Specifically, FIG. 10C shows the path of the driving current flowing from the low potential source 12 to the ground (GND) when the low potential source 12, the second conductive path CD2, the second wire SA2, the common conductive path CD0, and the ground (GND) are electrically connected in series. In this case, the second conductive path CD2 is realized by the second conductive member CM2 and the second fixed-side terminal plate 5F2 in FIG. 7C, and the common conductive path CD0 is realized by the first movable-side terminal plate 5M1, the first leaf spring 6A (the third portion 6A3, the fifth portion 6A5, and the second portion 6A2), and the sixth conductive member CM6 in FIG. 7C.

[0108] FIG. 10D shows an example of the path of the measurement current flowing through one shape memory alloy wire SA (first wire SA1). The path of the current shown in FIG. 7B is one of the specific examples of the path of the current shown in FIG. 10D. Specifically, FIG. 10D shows the path of the measurement current flowing from the constant current source 13 to the ground (GND) when the constant current source 13, the first conductive path CD1, the first wire SA1, the common conductive path CD0, and the ground (GND) are electrically connected in series. In this case, the first conductive path CD1 is realized by the first conductive member CM1 and the first fixed-side terminal plate 5F1 in FIG. 7B, and the common conductive path CD0 is realized by the first movable-side terminal plate 5M1, the first leaf spring 6A (the third portion 6A3, the fifth portion 6A5, and the second portion 6A2), and the sixth conductive member CM6 in FIG. 7B.

[0109] In this state, one input of the sixth active element AE6 is connected to the first measurement point MP1 on the conductive path between the first active element AE1 and the second active element AE2, and the other input of the sixth active element AE6 is connected to the second measurement point MP2 on the common conductive path CD0. Therefore, the sixth active element AE6 as an operational amplifier outputs the potential difference (voltage) between the potential at the first measurement point MP1 and the potential at the second measurement point MP2 to the control device 20. The control device 20 can calculate the resistance magnitude of the first wire SA1 based on the magnitude of the voltage and the magnitude of the current output by the constant current source 13. The control device 20 can calculate the resistance magnitude of each of the second wire SA2 to the fourth wire SA4 in the same way.

[0110] Next, with reference to FIG. 11, an example of the timing relationship between the driving current and the measuring current flowing through the shape memory alloy wire SA will be described. FIG. 11 is an example of a timing chart of the driving current and the measuring current flowing through each of the first wire SA1 to the fourth wire SA4. Specifically, FIG. 11 shows the timing relationship between the driving current and the measuring current flowing through each of the first wire SA1 to the fourth wire SA4 by showing the time transition of the voltage applied to each of the first wire SA1 to the fourth wire SA4. Note that the following description with reference to FIG. 11 relates to the timing relationship between the driving current and the measuring current flowing through each of the first wire SA1 to the fourth wire SA4, but is similarly applicable to the timing relationship between the driving current and the measuring current flowing through each of the fifth wire SA5 to the eighth wire SA8.

[0111] In the example shown in FIG. 11, the control of the driving device 10 by the control device 20 is realized by a pulse width modulation method. Note that the control of the driving device 10 by the control device 20 may be realized by other methods such as a pulse amplitude modulation method.

[0112] Specifically, the control device 20 controls the drive device 10 such that a drive current flows through the first wire SA1 during the period of the first drive time slot D1, a drive current flows through the second wire SA2 during the period of the second drive time slot D2, a drive current flows through the third wire SA3 during the period of the third drive time slot D3, and a drive current flows through the fourth wire SA4 during the period of the fourth drive time slot D4.

[0113] The first drive time slot D1 is a time slot preset as a period during which a drive current can flow through the first wire SA1. The same applies to the second drive time slot D2 to the fourth drive time slot D4. In the illustrated example, the drive device 10 is configured such that the sizes (durations) of the first drive time slot D1 to the fourth drive time slot D4 are the same. However, the drive device 10 may be configured such that the sizes (durations) of the first drive time slot D1 to the fourth drive time slot D4 are different from each other.

[0114] Also, the control device 20 controls the drive device 10 such that a measurement current flows through the first wire SA1 during the period of the first measurement time slot M1, a measurement current flows through the second wire SA2 during the period of the second measurement time slot M2, a measurement current flows through the third wire SA3 during the period of the third measurement time slot M3, and a measurement current flows through the fourth wire SA4 during the period of the fourth measurement time slot M4.

[0115] The first measurement time slot M1 is a time slot preset as a period during which a measurement current can flow through the first wire SA1. During the period of the first measurement time slot M1, drive currents are not supplied to any of the first wire SA1 to the fourth wire SA4. Therefore, the period of the first measurement time slot M1 is also referred to as the "PWM OFF period" when the pulse width modulation method is adopted. The same applies to the second measurement time slot M2 to the fourth measurement time slot M4. In the illustrated example, the drive device 10 is configured such that the sizes (durations) of the first measurement time slot M1 to the fourth measurement time slot M4 are the same. However, the drive device 10 may be configured such that the sizes (durations) of the first measurement time slot M1 to the fourth measurement time slot M4 are different from each other. Also, in the illustrated example, the duration of the measurement current is the same as the duration of the measurement time slot, but it may be shorter or longer than the duration of the measurement time slot.

[0116] Also, in the illustrated example, the control device 20 controls the drive device 10 such that the combination of the first drive time slot D1 to the fourth drive time slot D4 and the first measurement time slot M1 constitutes the first drive cycle, the combination of the first drive time slot D1 to the fourth drive time slot D4 and the second measurement time slot M2 constitutes the second drive cycle, the combination of the first drive time slot D1 to the fourth drive time slot D4 and the third measurement time slot M3 constitutes the third drive cycle, and the combination of the first drive time slot D1 to the fourth drive time slot D4 and the fourth measurement time slot M4 constitutes the fourth drive cycle.

[0117] Note that in the illustrated example, the control device 20 controls the drive device 10 such that the first measurement time slot M1 is set after the first to fourth drive time slots D1 to D4 in the first drive cycle. However, the drive device 10 may be controlled such that the first measurement time slot is set between two drive time slots. For example, the control device 20 may control the drive device 10 such that the first measurement time slot M1 is set between the first drive time slot D1 and the second drive time slot D2. The same applies to the second to fourth drive cycles.

[0118] Also, in the illustrated example, the control device 20 controls the drive device 10 such that a combination of the first, second, third, and fourth drive cycles constitutes one measurement cycle. That is, the control device 20 controls the drive device 10 such that by executing one measurement cycle, the resistance magnitudes of each of the four shape memory alloy wires SA (the first wire SA1 to the fourth wire SA4) can be obtained.

[0119] Note that in the illustrated example, the control device 20 controls the drive device 10 such that the four drive cycles are executed in the order of the first, second, third, and fourth drive cycles. However, the drive device 10 may be controlled such that the four drive cycles are executed in another order.

[0120] Also, in the illustrated example, the control device 20 controls the drive device 10 such that the resistance magnitude of one shape memory alloy wire SA can be obtained when executing one drive cycle. However, the drive device 10 may be controlled such that the resistance magnitudes of two or more shape memory alloy wires SA can be obtained when executing one drive cycle. For example, the first drive cycle may be configured by a combination of the first to fourth drive time slots D1 to D4, the first measurement time slot M1, and the second measurement time slot M2. In this case, the second measurement time slot M2 in the second drive cycle may be omitted.

[0121] In the example shown in FIG. 11, at time t1, the first driving time slot D1 of the first driving cycle starts, at time t2, the first driving time slot D1 ends and the second driving time slot D2 starts, at time t3, the second driving time slot D2 ends and the third driving time slot D3 starts, at time t4, the third driving time slot D3 ends and the fourth driving time slot D4 starts, at time t5, the fourth driving time slot D4 ends and the first measurement time slot M1 starts, and at time t6, the first measurement time slot M1 ends and the first driving time slot D1 of the second driving cycle starts.

[0122] Then, in the first driving time slot D1 of the first driving cycle, the control device 20 controls the driving device 10 so that a driving current flows through the first wire SA1 for a duration E1 that is the same as the duration of the first driving time slot D1. Also, in the second driving time slot D2 of the first driving cycle, the control device 20 controls the driving device 10 so that a driving current flows through the second wire SA2 for a duration E2 that is shorter than the duration of the second driving time slot D2. Also, in the third driving time slot D3 of the first driving cycle, the control device 20 controls the driving device 10 so that a driving current flows through the third wire SA3 for a duration E3 that is shorter than the duration of the third driving time slot D3. Also, in the fourth driving time slot D4 of the first driving cycle, the control device 20 controls the driving device 10 so that a driving current flows through the fourth wire SA4 for a duration E4 that is shorter than the duration of the fourth driving time slot D4. Also, in the first measurement time slot M1 of the first driving cycle, the control device 20 controls the driving device 10 so that a measurement current flows through the first wire SA1 for a duration E5 that is the same as the duration of the first measurement time slot M1.

[0123] The duration E5 during which the measurement current flows through the first wire SA1 is set according to, for example, the conversion speed of an AD converter for converting the analog signal output by the sixth active element AE6 as an operational amplifier into a digital signal. The faster the conversion speed of the AD converter, the shorter the duration E5 can be set. In other words, if the control device 20 sets the duration E5 to be longer, that is, if the measurement time is set to be longer, even if an AD converter with a slow conversion speed is used, the resistance of the four shape memory alloy wires SA can be accurately obtained.

[0124] Also, in the configuration where the resistance of the first wire SA1 is measured while the drive current is flowing through the first wire SA1, the duration E1 during which the drive current flows through the first wire SA1 needs to be set to be longer than the minimum duration determined by the conversion speed of the AD converter. However, in the configuration according to this embodiment, since the first drive time slot D1 and the first measurement time slot M1 are set separately, it is not necessarily required that the duration E1 is equal to or longer than the duration E5. That is, the control device 20 can adopt a duration E1 that is shorter than the duration E5 during which the measurement current flows through the first wire SA1. The same applies to the second wire SA2 to the fourth wire SA4.

[0125] Also, in the illustrated example, the drive device 10 includes a first drive device 10A configured to be able to drive each of the first wire SA1 to the fourth wire SA4, and a second drive device 10B configured to be able to drive each of the fifth wire SA5 to the eighth wire SA8. That is, the imaging device 101 is configured to include two drive devices capable of driving four shape memory alloy wires SA. This configuration increases the drive time slot assignable to one shape memory alloy wire SA and can reduce the magnitude of the current when supplying a desired amount of electric power to one shape memory alloy wire SA, compared to a configuration including only one drive device capable of driving eight shape memory alloy wires SA. As a result, the magnetic field formed around the conduction path can be reduced. However, the imaging device 101 may be configured to include only one drive device capable of driving eight shape memory alloy wires SA. In this case, the control device 20 may control the one drive device such that, for example, one measurement cycle is composed of eight drive cycles, and one drive cycle is composed of a combination of eight drive time slots and one measurement time slot. Alternatively, the imaging device 101 may be configured to include four drive devices capable of driving two shape memory alloy wires SA, or may be configured to include eight drive devices capable of driving one shape memory alloy wire SA.

[0126] Also, in the illustrated example, the control device 20 controls the drive device 10 such that drive current is supplied to one shape memory alloy wire SA in one drive time slot. However, the drive device 10 may be controlled such that drive current is simultaneously supplied to a plurality of shape memory alloy wires SA in one drive time slot. Even if drive current is simultaneously supplied to a plurality of shape memory alloy wires SA in one drive time slot, since the drive time slot and the measurement time slot are separated, the control device 20 can accurately measure the resistance value of each of the plurality of shape memory alloy wires SA. Specifically, in a configuration where the resistance value of a shape memory alloy wire is measured while drive current is being supplied to the shape memory alloy wire, if drive current (measurement current) is simultaneously supplied to a plurality of shape memory alloy wires, it becomes impossible to accurately measure the resistance value of each of those plurality of shape memory alloy wires. This is because the magnitudes of the drive currents (measurement currents) flowing through each of the plurality of shape memory alloy wires affect each other and become unstable. In contrast, in a configuration where the drive time slot and the measurement time slot are separated, such a problem does not occur.

[0127] Next, referring to FIGS. 12A and 12B, another example of the timing relationship between the driving current and the measuring current flowing through the shape memory alloy wire SA will be described. FIG. 12A is a perspective view of a first conductive member CM1 that forms part of a first conductive path CD1 (see FIG. 9) and a second conductive member CM2 that forms part of a second conductive path CD2 (see FIG. 9). FIG. 12B is another example of a timing chart of the driving current and the measuring current flowing through each of the first wire SA1 to the fourth wire SA4, and corresponds to FIG. 11. Specifically, FIG. 12B shows the timing relationship between the driving current and the measuring current flowing through each of the first wire SA1 to the fourth wire SA4 by showing the time change of the voltage applied to each of the first wire SA1 to the fourth wire SA4. Note that the following description with reference to FIG. 12A relates to the current flowing through each of the first conductive member CM1 and the second conductive member CM2, but is similarly applicable to the current flowing through each of the third conductive member CM3 and the fourth conductive member CM4. Also, the following description with reference to FIGS. 12A and 12B relates to the timing relationship between the driving current and the measuring current flowing through each of the first wire SA1 to the fourth wire SA4, but is similarly applicable to the timing relationship between the driving current and the measuring current flowing through each of the fifth wire SA5 to the eighth wire SA8.

[0128] In the example shown in FIG. 12B, the control device 20 controls the drive device 10 such that a drive current flows through each of the first wire SA1 and the second wire SA2 during a period combining the first drive time slot D1 and the second drive time slot D2, and a drive current flows through each of the third wire SA3 and the fourth wire SA4 during a period combining the third drive time slot D3 and the fourth drive time slot D4.

[0129] Specifically, the control device 20 controls the drive device 10 such that a drive current simultaneously flows through each of the first wire SA1 and the second wire SA2 over a period from time t1 to time td, that is, a duration E11 shorter than the duration of the first drive time slot D1.

[0130] More specifically, as shown in FIG. 10A, the control device 20 electrically connects the high potential source 11, the first conductive path CD1, the first wire SA1, the common conductive path CD0, the second wire SA2, the second conductive path CD2, and the ground (GND) in series to control the driving device 10 so that a relatively large current is simultaneously supplied to the first wire SA1 and the second wire SA2. That is, as indicated by the arrow AR61 in FIG. 12A, the control device 20 controls the driving device 10 such that current flows from the first point PT1 to the second point PT2 of the first conductive path CD1 (the first conductive member CM1), and at the same time, as indicated by the arrow AR62 in FIG. 12A, current flows from the second point PT12 to the first point PT11 of the second conductive path CD2 (the second conductive member CM2). Hereinafter, the operation mode of the driving device 10 at this time is referred to as the "first mode", and the state of the imaging device 101 at this time is referred to as the "strong driving state". Also, since the first wire SA1 and the second wire SA2 are simultaneously driven in this state, it is also referred to as the "common driving state".

[0131] In this "strong driving state", the direction of the current flowing through the first conductive path CD1 (the first conductive member CM1) (the direction represented by the arrow AR61) and the direction of the current flowing through the second conductive path CD2 (the second conductive member CM2) (the direction represented by the arrow AR62) are opposite to each other. Therefore, the magnetic field formed around the first conductive path CD1 (the first conductive member CM1) and the magnetic field formed around the second conductive path CD2 (the second conductive member CM2) cancel each other out. As a result, the net magnetic field (induced magnetic field) that can affect the image quality of the imaging element is reduced or eliminated.

[0132] In addition, by causing the driving device 10 to execute the "first mode" that realizes the "common driving state", the control device 20 has the effect of being able to extend the "PWM OFF period" when the pulse width modulation method is adopted compared to the case where the "first mode" is not executed.

[0133] Thereafter, the control device 20 controls the drive device 10 so that a drive current flows only through one of the first wire SA1 or the second wire SA2 during the remaining period of the period combining the first drive time slot D1 and the second drive time slot D2, and a drive current flows only through one of the third wire SA3 or the fourth wire SA4 during the remaining period of the period combining the third drive time slot D3 and the fourth drive time slot D4.

[0134] In the example shown in FIG. 12B, the control device 20 controls the drive device 10 so that a drive current flows only through the first wire SA1 over a period from time td to time te, that is, a duration E12 shorter than the duration of the first drive time slot D1.

[0135] More specifically, as shown in FIG. 10B, the control device 20 controls the drive device 10 to electrically connect the low potential source 12, the first conductive path CD1, the first wire SA1, the common conductive path CD0, and the ground (GND) in series so that a relatively small current is supplied to the first wire SA1. That is, the control device 20 controls the drive device 10 so that, as indicated by the arrow AR61 in FIG. 12A, current flows from the first point PT1 to the second point PT2 of the first conductive path CD1 (first conductive member CM1), and no current flows through the second conductive path CD2 (second conductive member CM2). Hereinafter, the operation mode of the drive device 10 at this time is referred to as the "second mode", and the state of the imaging device 101 at this time is referred to as the "weak drive state" or the "first weak drive state".

[0136] In the example shown in FIG. 12B, the sum of the amount of power supplied to the first wire SA1 in the "strong drive state" of the first drive cycle and the amount of power supplied to the first wire SA1 in the "first weak drive state" of the first drive cycle corresponds to the amount of power supplied to the first wire SA1 when the high potential source 11 and the first wire SA1 are connected over the duration of the first drive time slot D1. Note that FIG. 12B shows the voltage waveform in the case where the high potential source 11 and the first wire SA1 are connected over the duration of the first drive time slot D1 by a dotted line.

[0137] Also, in the "first weak driving state", since the magnitude of the current flowing through the first conductive path CD1 (first conductive member CM1) is smaller than that in the "strong driving state", the magnitude of the magnetic field formed around the first conductive path CD1 (first conductive member CM1) is also reduced. As a result, even when no current is supplied to the second conductive path CD2 (second conductive member CM2) and no magnetic field is formed to cancel out the magnetic field formed around the first conductive path CD1 (first conductive member CM1), the magnetic field (induced magnetic field) that can adversely affect the image quality of the imaging device is reduced by the amount by which the magnitude of the current flowing through the first conductive path CD1 (first conductive member CM1) is reduced.

[0138] Further, the control device 20 may control the driving device 10 such that a driving current flows only through the second wire SA2 during the remaining period of the period in which the first driving time slot D1 and the second driving time slot D2 are combined, that is, after causing the driving device 10 to execute the "first mode" during the period in which the first driving time slot D1 and the second driving time slot D2 are combined.

[0139] More specifically, as shown in FIG. 10C, the control device 20 may control the driving device 10 to electrically connect the low potential source 12, the second conductive path CD2, the second wire SA2, the common conductive path CD0, and the ground (GND) in series so that a relatively small current is supplied to the second wire SA2. That is, the control device 20 may control the driving device 10 such that current flows from the first point PT11 to the second point PT12 of the second conductive path CD2 (second conductive member CM2) and no current flows through the first conductive path CD1 (first conductive member CM1). Hereinafter, the operation mode of the driving device 10 at this time is referred to as the "third mode", and the state of the imaging device 101 at this time is referred to as the "weak driving state" or the "second weak driving state".

[0140] Further, during the period when the first driving time slot D1 and the second driving time slot D2 are combined, the control device 20 may control the driving device 10 to execute the "third mode" after causing the driving device 10 to execute the "first mode" and the "second mode". For example, the control device 20 may control the driving device 10 so that a driving current flows only through the second wire SA2 over a period from time tf to time tg, that is, a duration E13 shorter than the duration of the second driving time slot D2. For example, this is for fine adjustment of the amount of electric power supplied to the second wire SA2. Note that FIG. 12B shows a voltage waveform in dotted lines in the case where the low potential source 12 and the second wire SA2 are connected over a period from time tf to time tg. Thus, the driving device 10 may be configured to execute a combination of the "first mode", the "second mode", and the "third mode".

[0141] Note that the state of the imaging device 101 when the driving device 10 executes the "second mode" or the "third mode" is also referred to as the "individual driving state" because the first wire SA1 or the second wire SA2 is individually driven.

[0142] The control device 20 can supply a desired amount of electric power to each of the four shape memory alloy wires SA (first wire SA1 to fourth wire SA4) by causing the drive device 10 to execute a composite mode combining the "first mode" and the "second mode" or the "third mode". The "first mode" for the first wire SA1 and the second wire SA2 can be more effective as the amount of electric power to be supplied to the first wire SA1 and the amount of electric power to be supplied to the second wire SA2 are larger and the difference between them is smaller. This is because a large amount of electric power can be supplied to each of the first wire SA1 and the second wire SA2 in a short time while suppressing an adverse effect on the image quality of the imaging device. Further, as the difference between the amount of electric power to be supplied to the first wire SA1 and the amount of electric power to be supplied to the second wire SA2 is larger, the "second mode" or the "third mode" becomes more dominant in the time axis. However, the control device 20 can reduce the adverse effect on the image quality of the imaging device by making the duration of the "second mode" or the "third mode" as long as possible. This is because the current flowing through the first conduction path CD1 (first conductive member CM1) or the second conduction path CD2 (second conductive member CM2) can be reduced, and the magnetic field formed around the first conduction path CD1 (first conductive member CM1) or the second conduction path CD2 (second conductive member CM2) can be reduced.

[0143] Note that, in the illustrated example, when the control device 20 causes the drive device 10 to execute the "second mode", as shown in FIG. 10B, the control device 20 controls the drive device 10 such that the low potential source 12 having a fixed potential is connected to the first wire SA1. However, when the control device 20 causes the drive device 10 to execute the "second mode", it may be configured such that a variable potential source having an adjustable potential is connected to the first wire SA1. In this case, the control device 20 controls the drive device 10 such that the amount of electric power supplied to the first wire SA1 when the low potential source 12 and the first wire SA1 are connected is the same as the amount of electric power supplied to the first wire SA1 by decreasing the potential of the variable potential source to be smaller than the potential of the low potential source 12 and increasing the duration E12 to the duration E12a. That is, the control device 20 may increase the duration E12a as long as possible in order to make the potential of the variable potential source as low as possible. Note that FIG. 12B shows a voltage waveform in the case where the variable potential source and the first wire SA1 are connected over the duration E12a by a dotted line. The state of the imaging device 101 at this time is referred to as the "variable weak drive state". In this "variable weak drive state", compared with the "first weak drive state", the magnitude of the current flowing through the first conduction path CD1 (first conductive member CM1) becomes smaller, so that the magnitude of the magnetic field formed around the first conduction path CD1 (first conductive member CM1) is further reduced. The same applies when the control device 20 causes the drive device 10 to execute the "third mode".

[0144] Note that the change in the magnitude of the potential of the variable potential source is preferably made with a change period that is sufficiently long with respect to the period of the measurement cycle. In the example shown in FIG. 12B, the change is made in synchronization with the measurement cycle. For example, the change may be made each time a single measurement cycle composed of a first drive cycle, a second drive cycle, a third drive cycle, and a fourth drive cycle is executed and the resistance values of the four shape memory alloy wires SA (first wire SA1 to fourth wire SA4) are acquired. In this case, the change may be made during the period of the fourth measurement time slot M4.

[0145] Next, referring to FIG. 13, another configuration example of the drive device 10 will be described. FIG. 13 is a diagram showing another configuration example of the drive device 10. Note that the following description with reference to FIG. 13 relates to the first drive device 10A configured to be able to drive each of the first wire SA1 to the fourth wire SA4, but is similarly applicable to the second drive device 10B configured to be able to drive each of the fifth wire SA5 to the eighth wire SA8. Also, in FIG. 13, for clarity, the illustration of the configuration of active elements and the like for estimating the resistance value of each of the first wire SA1 to the fourth wire SA4 is omitted, but such a configuration is actually connected.

[0146] The first drive device 10A shown in FIG. 13 is different from the first drive device 10A shown in FIG. 9 in that it includes five active elements AE (the tenth active element AE10 to the fourteenth active element AE14).

[0147] The tenth active element AE10 is a switching element that controls the connection between a common conduction path CD0 connected to the other end of each of the first wire SA1 to the fourth wire SA4 and either a low potential source (LOW) or a ground (GND).

[0148] The eleventh active element AE11 is a switching element that controls the connection between a first conduction path CD1 connected to one end of the first wire SA1 and either a high potential source (HIGH) or a low potential source (LOW).

[0149] The twelfth active element AE12 is a switching element that controls the connection between a second conduction path CD2 connected to one end of the second wire SA2 and a ground (GND).

[0150] The thirteenth active element AE13 is a switching element that controls the connection between a third conduction path CD3 connected to one end of the third wire SA3 and either a high potential source (HIGH) or a low potential source (LOW).

[0151] The fourteenth active element AE14 is a switching element that controls the connection between a fourth conduction path CD4 connected to one end of the fourth wire SA4 and a ground (GND).

[0152] The control device 20 can supply a relatively large current to the first wire SA1 and the second wire SA2 simultaneously by controlling the eleventh active element AE11 and the twelfth active element AE12 so that the high potential source (HIGH), the first conductive path CD1, the first wire SA1, the common conductive path CD0, the second wire SA2, and the ground (GND) are electrically connected in series. Further, the control device 20 can supply a relatively small current to only the first wire SA1 by controlling the tenth active element AE10 and the eleventh active element AE11 so that the low potential source (LOW), the first conductive path CD1, the first wire SA1, the common conductive path CD0, and the ground (GND) are electrically connected in series. Further, the control device 20 can supply a relatively small current to only the second wire SA2 by controlling the tenth active element AE10 and the twelfth active element AE12 so that the low potential source (LOW), the common conductive path CD0, the second wire SA2, the second conductive path CD2, and the ground (GND) are electrically connected in series.

[0153] Similarly, the control device 20 can supply a relatively large current to the third wire SA3 and the fourth wire SA4 simultaneously by controlling the thirteenth active element AE13 and the fourteenth active element AE14 so that the high potential source (HIGH), the third conductive path CD3, the third wire SA3, the common conductive path CD0, the fourth wire SA4, and the ground (GND) are electrically connected in series. Further, the control device 20 can supply a relatively small current to only the third wire SA3 by controlling the tenth active element AE10 and the thirteenth active element AE13 so that the low potential source (LOW), the third conductive path CD3, the third wire SA3, the common conductive path CD0, and the ground (GND) are electrically connected in series. Further, the control device 20 can supply a relatively small current to only the fourth wire SA4 by controlling the tenth active element AE10 and the fourteenth active element AE14 so that the low potential source (LOW), the common conductive path CD0, the fourth wire SA4, the fourth conductive path CD4, and the ground (GND) are electrically connected in series.

[0154] Also, in the example shown in FIG. 13, the high potential source (HIGH) may be configured such that, although the potential is fixed, the potential dynamically changes according to a control signal from the control device 20. Conversely, the low potential source (LOW) may be configured such that the potential is fixed, although the potential dynamically changes according to a control signal from the control device 20.

[0155] Alternatively, the drive device 10 shown in FIG. 13 may be configured such that one end of each of the first wire SA1 to the fourth wire SA4 can be selectively connected to the ground (GND) via an active element such as an N-channel transistor in a state where the other end of each of the first wire SA1 to the fourth wire SA4 is connected to a potential source having a potential of 3V or the like.

[0156] Even in such a configuration, the drive device 10 can execute a composite mode combining the "first mode" and the "second mode" or the "third mode". Further, the drive device 10 can execute a composite mode combining the "first mode", the "second mode", and the "third mode". Further, the drive device 10 can supply a measurement current to each of the eight shape memory alloy wires SA at a timing different from the timing at which the drive current is supplied.

[0157] As described above, as shown in FIG. 2, the imaging device 101 according to the embodiment of the present invention includes a fixed-side member FB including a base member 18 as a fixed base, a lens holder 2 capable of holding a lens body, a movable-side member MB movably provided with respect to the fixed-side member FB, a plurality of shape memory alloy wires SA having one end fixed to the fixed-side member FB and the other end fixed to the movable-side member MB and capable of moving the movable-side member MB, a driving device 10 (see FIG. 9) capable of driving each of the plurality of shape memory alloy wires SA by supplying a driving current to each of the plurality of shape memory alloy wires SA, and a control device 20 (see FIG. 9) capable of acquiring the resistance value of each of the plurality of shape memory alloy wires SA and controlling the driving device 10. The control device 20 is configured to control the driving device 10 so that a measurement current is supplied to each of the plurality of shape memory alloy wires SA at a timing different from the timing when the driving current is supplied, and to acquire the resistance value (measured resistance value) of each of the plurality of shape memory alloy wires SA.

[0158] Note that the control device 20 is configured to be able to set the target length (target resistance value) of each of the eight shape memory alloy wires SA corresponding to the desired posture of the lens holder 2 (lens body). Then, the control device 20 is configured to realize the desired posture of the lens holder 2 (lens body) by controlling the driving device 10 so that the difference between the measured resistance value and the target resistance value of each of the eight shape memory alloy wires SA approaches zero. Further, the control device 20 can contract a specific one of the shape memory alloy wires SA by increasing the amount of electric power supplied to the specific one of the shape memory alloy wires SA and reduce its measured resistance value.

[0159] This configuration brings about the effect that the length of the shape memory alloy wire SA can be estimated more accurately. This is because in this configuration, the time for which the measurement current is supplied is set regardless of the time for which the supply of the driving current is continued. That is, in this configuration, the time for which the measurement current is supplied is set to a necessary and sufficient length.

[0160] Further, when this configuration includes an AD converter for detecting the voltage across both ends of the shape memory alloy wire SA to derive the resistance value of the shape memory alloy wire SA, it can have the effect of allowing the operating speed of the AD converter to be set lower, that is, allowing a relatively inexpensive AD converter to be used. In this configuration, since the measurement current is supplied to the shape memory alloy wire SA at a timing different from the timing of supplying the driving current, that is, since the time for which the supply of the measurement current continues can be set relatively freely.

[0161] Further, the control device 20 may control the driving device 10 so as to supply the driving current to each of the plurality of shape memory alloy wires SA at different timings.

[0162] This configuration has the effect of enabling more accurate control of the expansion and contraction of each of the plurality of shape memory alloy wires SA. This is because it can prevent a part of the driving current to be supplied to a specific shape memory alloy wire SA from being supplied to another shape memory alloy wire SA.

[0163] Further, the control device 20 may control the driving device 10 so as to supply the measurement current to each of the plurality of shape memory alloy wires SA at different timings.

[0164] This configuration has the effect of enabling more accurate acquisition of the resistance value of each of the plurality of shape memory alloy wires SA. This is because it can prevent a part of the measurement current to be supplied to a specific shape memory alloy wire SA from being supplied to another shape memory alloy wire SA.

[0165] Further, the control device 20 may control the driving device 10 such that the minimum value of the time for continuously supplying the driving current to each of the plurality of shape memory alloy wires SA is shorter than the time for continuously supplying the measurement current to each of the plurality of shape memory alloy wires SA.

[0166] This configuration has the effect of enabling more flexible adjustment of the duration for which the driving current is supplied. This is because the duration for which the driving current is supplied can be made shorter than the duration for which the measurement current is supplied. Note that being able to shorten the duration for which the driving current is supplied means that the amount of electric power supplied to a specific single shape memory alloy wire SA in one driving cycle (driving time slot) can be reduced, that is, the shape memory alloy wire SA can be slightly heated and slightly contracted.

[0167] Further, the control device 20 may control the drive device 10 such that the magnitude of the measurement current is smaller than the magnitude of the driving current.

[0168] This configuration has the effect of reducing the influence of the measurement current on the driving of the shape memory alloy wire SA.

[0169] Further, the control device 20 may control the drive device 10 to supply the driving current to each of the plurality of shape memory alloy wires SA one by one in one driving cycle, and to supply the measurement current to any one of the plurality of shape memory alloy wires SA. Then, the control device 20 may control the drive device 10 to supply the measurement current to each of the plurality of shape memory alloy wires SA by repeating the driving cycle a plurality of times.

[0170] This configuration has the effect of enabling smoother driving of the lens holder 2 (lens body). This is because the driving current can be supplied to each of the plurality of shape memory alloy wires SA at relatively short intervals. Also, this is because it is possible to prevent the period during which the driving current cannot be supplied to one of the plurality of shape memory alloy wires SA from becoming excessively long.

[0171] Further, the control device 20 may control the drive device 10 to supply a measurement current to each of the plurality of shape memory alloy wires SA by repeating the drive cycle the same number of times as the number of the plurality of shape memory alloy wires SA.

[0172] This configuration has the effect of suppressing a decrease in the control response speed and enabling the lens holder 2 (lens body) to be driven more smoothly. This is because the measurement current can be supplied to each of the plurality of shape memory alloy wires SA at relatively short intervals. Also, this is because it is possible to suppress an excessive lengthening of the period during which the measurement current cannot be supplied to one of the plurality of shape memory alloy wires SA.

[0173] Further, the drive device 10 may include a first drive device 10A capable of driving each of the four shape memory alloy wires (first wire SA1 to fourth wire SA4) by supplying a drive current to each of the four shape memory alloy wires, and a second drive device 10B capable of driving each of another four shape memory alloy wires (fifth wire SA5 to eighth wire SA8) by supplying a drive current to each of the another four shape memory alloy wires.

[0174] This configuration has the effect of shortening the time required for one drive cycle. That is, this configuration has the effect of suppressing a decrease in the control response speed. Also, this configuration has the effect of being able to lengthen the duration of the measurement time slot without increasing the time required for one drive cycle as compared with the case of providing one drive device that supplies a drive current to each of the eight shape memory alloy wires (first wire SA1 to eighth wire SA8) to drive each of the eight shape memory alloy wires. Therefore, this configuration does not need to increase the applied voltage when supplying the drive current to the shape memory alloy wire SA in order to lengthen the duration of the measurement time slot. As a result, this configuration can suppress the influence on the image due to noise caused by increasing the applied voltage.

[0175] Also, as shown in FIG. 2, the imaging device 101 according to an embodiment of the present invention includes a fixed-side member FB including a base member 18 as a fixed base, a movable-side member MB movable with respect to the fixed-side member FB including a lens holder 2 capable of holding a lens body so as to face an imaging element, a first wire SA1 as a first shape memory alloy wire having one end fixed to the fixed-side member FB and the other end fixed to the movable-side member MB, a second wire SA2 as a second shape memory alloy wire having one end fixed to the fixed-side member FB and the other end fixed to the movable-side member MB, a first conductive path CD1 (see FIG. 9) provided on the base member 18 and electrically connected to one end of the first wire SA1, a second conductive path CD2 (see FIG. 9) provided on the base member 18 and electrically connected to one end of the second wire SA2, a common conductive path CD0 (see FIG. 9) electrically connected to the other ends of the first wire SA1 and the second wire SA2, and a driving device 10 (see FIG. 9) configured to be electrically connected to each of the first conductive path CD1, the second conductive path CD2, and the common conductive path CD0 and capable of supplying current to each of the first wire SA1 and the second wire SA2 to drive each of the first wire SA1 and the second wire SA2. Then, as shown in FIG. 12A, a portion connecting a first point PT1 and a second point PT2 on the first conductive path CD1 (first conductive member CM1), and a portion connecting a first point PT11 and a second point PT12 on the second conductive path CD2 (second conductive member CM2) are installed in parallel with each other on the base member 18. Further, the first point PT1 on the first conductive path CD1 (first conductive member CM1) is arranged side by side with the first point PT11 on the second conductive path CD2 (second conductive member CM2), and the second point PT2 on the first conductive path CD1 (first conductive member CM1) is arranged side by side with the second point PT12 on the second conductive path CD2 (second conductive member CM2).Then, as shown in FIG. 10A, the drive device 10 electrically connects the first conductive path CD1, the first wire SA1, the common conductive path CD0, the second wire SA2, and the second conductive path CD2 in series to supply current to the first wire SA1 and the second wire SA2. As shown by the arrow AR61 in FIG. 12A, current flows from the first point PT1 to the second point PT2 of the first conductive path CD1 (first conductive member CM1), and as shown by the arrow AR62 in FIG. 12A, current flows from the second point PT12 to the first point PT11 of the second conductive path CD2 (second conductive member CM2). There is a first mode, and as shown in FIG. 10B, the first conductive path CD1, the first wire SA1, and the common conductive path CD0 are electrically connected in series to supply current to the first wire SA1 so that current flows through the first conductive path CD1 (first conductive member CM1). There is a second mode, and as shown in FIG. 10C, the second conductive path CD2, the second wire SA2, and the common conductive path CD0 are electrically connected in series to supply current to the second wire SA2 so that current flows through the second conductive path CD2 (second conductive member CM2). The drive device 10 is configured to be able to switch between the third mode. The imaging device 101 is configured to be able to execute a combination of the first mode and at least one of the second mode and the third mode.

[0176] This configuration has the effect of reducing the magnitude of the magnetic field formed around the conductive path for supplying current to the shape memory alloy wire SA. Therefore, this configuration has the effect of reducing the noise on the imaging element caused by the magnetic field formed around the conductive path.

[0177] This is because the magnetic field formed by the current flowing through the first conductive path CD1 is canceled out by the magnetic field formed by the current flowing through the second conductive path CD2. Specifically, in the first mode, the drive device 10 is configured such that currents flow in opposite directions through the first conductive path CD1 (first conductive member CM1) and the second conductive path CD2 (second conductive member CM2) which are arranged in parallel with each other as shown in FIG. 12A. This is because the magnitude of the current flowing through the first conductive path CD1 (first conductive member CM1) is the same as the magnitude of the current flowing through the second conductive path CD2 (second conductive member CM2).

[0178] In addition, since the drive device 10 is configured to execute a composite mode that combines at least one of the first mode, the second mode, and the third mode, a desired amount of electric power can be accurately supplied to each of the first wire SA1 and the second wire SA2. Note that the combination of at least one of the first mode, the second mode, and the third mode is a combination of the first mode and the second mode, a combination of the first mode and the third mode, or a combination of the first mode, the second mode, and the third mode. Further, in the composite mode that combines at least one of the first mode, the second mode, and the third mode, any operation mode may be executed first, each operation mode may be executed continuously, or a measurement time slot or a PWM OFF period may be inserted between the operation modes. Further, the composite mode that combines at least one of the first mode, the second mode, and the third mode may be executed during one or more drive cycles, or may be executed during one or more measurement cycles.

[0179] In addition, the drive device 10 may be configured such that the magnitude of the current flowing in the first mode is greater than the magnitude of the current flowing in each of the second mode and the third mode.

[0180] This configuration has the effect of further reducing a magnetic field (induced magnetic field) that can have an adverse effect on the image quality of the imaging device. In the first mode, this is because the magnetic field formed by the current flowing through the first conductive path CD1 (first conductive member CM1) and the magnetic field formed by the current flowing through the second conductive path CD2 (second conductive member CM2) cancel each other out. Also, when supplying a desired amount of electric power to the first wire SA1, the larger the magnitude of the current flowing in the first mode, the smaller the magnitude of the current flowing in the second mode executed after the first mode can be. This is because the smaller the magnitude of the current flowing in the second mode, the smaller the magnetic field formed by the current flowing through the first conductive path CD1 (first conductive member CM1) in the second mode. Similarly, when supplying a desired amount of electric power to the second wire SA2, the larger the magnitude of the current flowing in the first mode, the smaller the magnitude of the current flowing in the third mode executed after the first mode can be. This is because the smaller the magnitude of the current flowing in the third mode, the smaller the magnetic field formed by the current flowing through the second conductive path CD2 (second conductive member CM2) in the third mode.

[0181] Also, the portion connecting the first point PT1 and the second point PT2 on the first conductive path CD1 (first conductive member CM1) and the portion connecting the first point PT11 and the second point PT12 on the second conductive path CD2 (second conductive member CM2) may be embedded in the base member 18.

[0182] This configuration has the effect of further reducing a magnetic field (induced magnetic field) that can have an adverse effect on the image quality of the imaging device. This is because the propagation of the magnetic field formed around the portion of the first conductive member CM1 embedded in the base member 18 and the propagation of the magnetic field formed around the portion of the second conductive member CM2 embedded in the base member 18 to the imaging device are at least partially suppressed by the base member 18.

[0183] Further, as shown in FIG. 4B, the first wire SA1 and the second wire SA2 may be arranged side by side in a plan view along the optical axis direction (Z-axis direction). Further, as shown in FIG. 4A, the first wire SA1 and the second wire SA2 may be arranged so as to cross each other in a side view along the direction (Y-axis direction) that is substantially perpendicular to the extending direction (X-axis direction) of each of the first wire SA1 and the second wire SA2 and perpendicular to the optical axis direction (Z-axis direction).

[0184] This configuration has the effect of further reducing the net magnetic field (induced magnetic field) that can affect the image quality of the imaging device. This is because in the state where currents are simultaneously supplied to the first wire SA1 and the second wire SA2 in the first mode (the state shown in FIG. 7A), the induced magnetic field formed around the first wire SA1 and the induced magnetic field formed around the second wire SA2 cancel each other out.

[0185] Further, as shown in FIG. 5, the base member 18 may have a rectangular frame shape having a first side portion 18E1, a second side portion 18E2, a third side portion 18E3, and a fourth side portion 18E4 in a plan view along the optical axis direction (Z-axis direction). Then, as shown in FIG. 12A, the first conductive path CD1 (see FIG. 9) may include the first terminal portion TM1, and the second conductive path CD2 (see FIG. 9) may include the second terminal portion TM2. Further, the first terminal portion TM1 and the second terminal portion TM2 may be disposed on the third side portion 18E3, which is one of the first side portion 18E1, the second side portion 18E2, the third side portion 18E3, and the fourth side portion 18E4. In this case, the portion connecting the first point PT1 and the second point PT2 on the first conductive path CD1 (first conductive member CM1), and the portion connecting the first point PT11 and the second point PT12 on the second conductive path CD2 (second conductive member CM2) may be arranged to be parallel along the second side portion 18E2, which is another one of the first side portion 18E1, the second side portion 18E2, the third side portion 18E3, and the fourth side portion 18E4.

[0186] This configuration brings about the effect of facilitating the implementation of the imaging device. This is because a flexible printed circuit board or the like connected to the imaging device can be disposed under the second side portion 18E2 of the base member 18.

[0187] In addition, the control method of the imaging device 101 according to the embodiment of the present invention includes a step in which the control device 20 controls the driving device 10 so that a measurement current is supplied to each of the plurality of shape memory alloy wires SA at a timing different from the timing at which the driving current is supplied, and the control device 20 acquires the resistance values of the plurality of shape memory alloy wires SA.

[0188] With this control method, the imaging device 101 can more accurately estimate the length of the shape memory alloy wire SA. This is because, in this control method, the time for which the measurement current is supplied is set regardless of the time for which the driving current is supplied. That is, in this control method, the time for which the measurement current is supplied is set to a length that is sufficiently long.

[0189] In addition, the control method of the imaging device 101 according to the embodiment of the present invention includes, as shown in FIG. 10A, electrically connecting the first conductive path CD1, the first wire SA1, the common conductive path CD0, the second wire SA2, and the second conductive path CD2 in series to supply current to the first wire SA1 and the second wire SA2, and, as shown in FIG. 12A, causing current to flow from the first point PT1 to the second point PT2 of the first conductive path CD1 (the first conductive member CM1) and from the second point PT12 to the first point PT11 of the second conductive path CD2 (the second conductive member CM2); a first mode; as shown in FIG. 10B, electrically connecting the first conductive path CD1, the first wire SA1, and the common conductive path CD0 in series to supply current to the first wire SA1 so that current flows through the first conductive path CD1; a second mode; and, as shown in FIG. 10C, electrically connecting the second conductive path CD2, the second wire SA2, and the common conductive path CD0 in series to supply current to the second wire SA2 so that current flows through the second conductive path CD2; and a third mode, and causing the driving device 10 to execute a composite mode combining at least one of the above modes.

[0190] With this control method, the imaging device 101 can reduce the magnitude of the magnetic field formed around the conductive path for supplying current to the shape memory alloy wire SA. Therefore, the imaging device 101 can reduce the noise on the imaging element caused by the magnetic field formed around the conductive path.

[0191] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments. Various modifications, substitutions, etc. can be applied to the above-described embodiments without departing from the scope of the present invention. Also, each of the features described with reference to the above embodiments may be appropriately combined as long as they are not technically contradictory.

[0192] This application claims priority based on Japanese Patent Application No. 2022-005275 filed on January 17, 2022, and the entire contents of this Japanese patent application are incorporated herein by reference.

Description of Reference Numerals

[0193] 2 ··· Lens Holder 2D ··· Movable Side Base Portion 2D1 ··· First Movable Side Base Portion 2D2 ··· Second Movable Side Base Portion 2P ··· Cylindrical Portion 2S ··· Protruding Portion 2S1 ··· First Protruding Portion 2S2 ··· Second Protruding Portion 2T ··· Projecting Portion 2V ··· Protrusion Portion 4 ··· Cover Member 4A ··· Outer Peripheral Wall Portion 4A1 ··· First Side Plate Portion 4A2 ··· Second Side Plate Portion 4A3 ··· Third Side Plate Portion 4A4 ··· Fourth Side Plate Portion 4B ··· Top Plate Portion 4K ··· Opening 4S ··· Storage Portion 5 ··· Metal Member 5F ··· Fixed Side Metal Member 5F1 ··· First Fixed Side Terminal Plate 5F2 ··· Second Fixed Side Terminal Plate 5F3 ··· Third Fixed Side Terminal Plate 5F4 ··· Fourth Fixed Side Terminal Plate 5F5 ··· Fifth Fixed Side Terminal Plate 5F6 ··· Sixth Fixed Side Terminal Plate 5F7 ··· Seventh Fixed Side Terminal Plate 5F8 ··· Eighth Fixed Side Terminal Plate 5M ··· Movable Side Metal Member 5M1 ··· First Movable Side Terminal Plate 5M2 ··· Second Movable Side Terminal Plate 5M3 ··· Third Movable Side Terminal Plate 5M4 ··· Fourth Movable Side Terminal Plate 6 ··· Leaf Spring 6A ··· First Leaf Spring 6A1 ··· First Portion 6A2 ··· Second Portion 6A3 ··· Third Portion 6A4 ··· Fourth Portion 6A5 ··· Fifth Portion 6AH1 ··· First Through Hole 6AH2 ··· Second Through Hole 6AH3 ··· Third Through Hole 6AH4 ··· Fourth Through Hole 6AH5 ··· Fifth Through Hole 6AH6 ··· Sixth Through Hole 6B ··· Second Leaf Spring 6B1 ··· First Portion 6B2 ··· Second Portion 6B3 ··· Third Portion 6B4 ··· Fourth Portion 6B5 ··· Fifth Portion 6BH1 ··· First Through Hole 6BH2 ··· Second Through Hole 6BH3 ··· Third Through Hole 6BH4 ··· Fourth Through Hole 6BH5 ··· Fifth Through Hole 6BH6 ··· Sixth Through Hole 10 ··· Driving Device 10A ··· First Driving Device 10A 10B ··· Second Driving Device 11 ··· High Potential Source 12 ··· Low Potential Source 13 ··· Constant Current Source 18 ··· Base Member 18D ··· Fixed Side Base Portion 18D1 ··· First Fixed Side Base Portion 18D2 ··· Second Fixed Side Base Portion 18E ··· Side Portion 18E1 ··· First Side Portion 18E2 ··· Second Side Portion 18E3 ··· Third Side Portion 18E4 ··· Fourth Side Portion 18K ··· Opening 18T ··· Projecting Portion 18V ··· Protrusion Portion101···Imaging device AE···Active element AE1···First active element AE2···Second active element AE3···Third active element AE4···Fourth active element AE5···Fifth active element AE6···Sixth active element AE10···Tenth active element AE11···Eleventh active element AE12···Twelfth active element AE13···Thirteenth active element AE14··· Fourteenth active element AH···Rectangular hole CD0···Common conductive path CD1···First conductive path CD2···Second conductive path CD3···Third conductive path CD4···Fourth conductive path CM···Conductive member CM1···First conductive member CM2···Second conductive member CM3···Third conductive member CM4···Fourth conductive member CM5···Fifth conductive member CM6···Sixth conductive member CP5···Fifth joint surface CP6···Sixth joint surface CT1···First contact part CT2···Second contact part CT3···Third contact part CT4···Fourth contact part CT5···Fifth contact part CT6···Sixth contact part CT7···Seventh contact part CT8···Eighth contact part CT9···Ninth contact part CT10···Tenth contact part CT11···Eleventh contact part CT12···Twelfth contact part ED1···First connection part ED2···Second connection part ED3···Third connection part ED4···Fourth connection part FB···Fixed-side member J1~J4···Holding part OA···Optical axis MB···Movable-side member FB···Fixed-side member MP1···First measurement point MP2···Second measurement point PT1, PT11···First point PT2, PT12···Second point RH···Through hole SA···Shape memory alloy wire SA1···First wire SA2···Second wire SA3···Third wire SA4···Fourth wire SA5···Fifth wire SA6···Sixth wire SA7···Seventh wire SA8···Eighth wire SD···Bonding material TM1···First terminal part TM2···Second terminal part TM3···Third terminal part TM4···Fourth terminal part TM5···Fifth terminal part TM6···Sixth terminal part

Claims

1. A fixed-side member including a fixed base, A movable-side member movable with respect to the fixed-side member, including a lens holder capable of holding a lens body so as to face an imaging element, A first shape memory alloy wire having one end fixed to the fixed-side member and the other end fixed to the movable-side member, A second shape memory alloy wire having one end fixed to the fixed-side member and the other end fixed to the movable-side member, A first conductive path provided on the fixed base and electrically connected to one end of the first shape memory alloy wire, A second conductive path provided on the fixed base and electrically connected to one end of the second shape memory alloy wire, A common conductive path electrically connected to the other ends of the first shape memory alloy wire and the second shape memory alloy wire, A driving device configured to be electrically connectable to each of the first conductive path, the second conductive path, and the common conductive path, and capable of supplying current to each of the first shape memory alloy wire and the second shape memory alloy wire to drive each of the first shape memory alloy wire and the second shape memory alloy wire, The portion connecting the first point and the second point on the first conductive path and the portion connecting the first point and the second point on the second conductive path are installed parallel to each other on the fixed base, The first point on the first conductive path is arranged in parallel with the first point on the second conductive path, The second point on the first conductive path is arranged in parallel with the second point on the second conductive path, The driving device is A first mode in which the first conductive path, the first shape memory alloy wire, the common conductive path, the second shape memory alloy wire, and the second conductive path are electrically connected in series to supply current to the first shape memory alloy wire and the second shape memory alloy wire so that current flows from the first point to the second point of the first conductive path and current flows from the second point to the first point of the second conductive path, A second mode in which the first conductive path, the first shape memory alloy wire, and the common conductive path are electrically connected in series to supply current to the first shape memory alloy wire so that current flows through the first conductive path, A third mode in which the second conductive path, the second shape memory alloy wire, and the common conductive path are electrically connected in series to supply current to the second shape memory alloy wire so that current flows through the second conductive path, configured to be switchable, and An imaging device characterized in that it is configured to execute a combination of the first mode and at least one of the second mode and the third mode.

2. The magnitude of the current flowing in the first mode is greater than the magnitude of the current flowing in each of the second mode and the third mode. The imaging device according to claim 1.

3. The portion connecting the first point and the second point on the first conductive path and the portion connecting the first point and the second point on the second conductive path are embedded in the fixed base. The imaging device according to claim 1.

4. The first shape memory alloy wire and the second shape memory alloy wire are arranged side by side in a plan view along the optical axis direction, and in a side view along a direction substantially perpendicular to the extending direction of each of the first shape memory alloy wire and the second shape memory alloy wire and perpendicular to the optical axis direction, they are arranged to intersect each other. The imaging device according to claim 1.

5. The fixed base has a rectangular frame shape having a first side portion, a second side portion, a third side portion, and a fourth side portion in a plan view along the optical axis direction. The first conductive path includes a first terminal portion. The second conductive path includes a second terminal portion. The first terminal portion and the second terminal portion are disposed on one of the first side portion, the second side portion, the third side portion, and the fourth side portion. The portion connecting the first point and the second point on the first conductive path and the portion connecting the first point and the second point on the second conductive path are arranged to be parallel along another one of the first side portion, the second side portion, the third side portion, and the fourth side portion. The imaging device according to claim 1.

6. The lens body, The imaging device according to any one of claims 1 to 5, A camera module including the same.

7. A fixed-side member including a fixed base, a movable-side member movable relative to the fixed-side member including a lens holder capable of holding a lens body so as to face an imaging element, a first shape memory alloy wire having one end fixed to the fixed-side member and the other end fixed to the movable-side member, a second shape memory alloy wire having one end fixed to the fixed-side member and the other end fixed to the movable-side member, a first conductive path provided on the fixed base and electrically connected to one end of the first shape memory alloy wire, a second conductive path provided on the fixed base and electrically connected to one end of the second shape memory alloy wire, a common conductive path electrically connected to the other ends of the first shape memory alloy wire and the second shape memory alloy wire respectively, and a drive device configured to be electrically connected to each of the first conductive path, the second conductive path, and the common conductive path and capable of supplying current to each of the first shape memory alloy wire and the second shape memory alloy wire to drive each of the first shape memory alloy wire and the second shape memory alloy wire. A control method for an imaging device comprising: A portion connecting a first point and a second point on the first conductive path and a portion connecting the first point and the second point on the second conductive path are installed on the fixed base so as to be parallel to each other. The first point on the first conductive path is arranged side by side with the first point on the second conductive path. The second point on the first conductive path is arranged side by side with the second point on the second conductive path. The control method of the imaging device includes a first mode in which the first conductive path, the first shape memory alloy wire, the common conductive path, the second shape memory alloy wire, and the second conductive path are electrically connected in series to supply current to the first shape memory alloy wire and the second shape memory alloy wire so that current flows from a first point to a second point of the first conductive path and current flows from the second point to the first point of the second conductive path; a second mode in which the first conductive path, the first shape memory alloy wire, and the common conductive path are electrically connected in series to supply current to the first shape memory alloy wire so that current flows through the first conductive path; and at least one of a third mode in which the second conductive path, the second shape memory alloy wire, and the common conductive path are electrically connected in series to supply current to the second shape memory alloy wire so that current flows through the second conductive path, and includes a step of causing the driving device to execute a composite mode combining the above modes. A control method of an imaging device, characterized by the above.

Images