Imaging device, camera module, and control method for the imaging device

Abstract

To provide an imaging apparatus which comprises a shape memory alloy wire and enables the length thereof to be more accurately estimated.SOLUTION: An imaging apparatus 101 comprises: a stationary-side member FB; a movable-side member MB which is movably provided in the stationary-side member FB; a plurality of shape memory alloy wires SA which are fixed at one end to the stationary-side member FB and fixed at other end to the movable-side member MB and can move the movable-side member MB; a drive device 10 which supplies drive current to each of the plurality of shape memory alloy wires SA and can drive each of the plurality of shape memory alloy wires SA; and a control device 20 which acquires the resistance value of each of the plurality of shape memory alloy wires SA and can control the drive device 10. The control device 20 controls the drive device 10 in such a way that current for measurement is supplied to each of the plurality of shape memory alloy wires SA at a timing different from a timing at which the drive current is supplied, and as a result, the control device 20 acquires the resistance value of the plurality of shape memory alloy wires SA.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an imaging device, a camera module, and a control method for 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 shrink 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, when the control circuit supplies a current (driving current) for heating and shrinking the shape memory alloy wire to the shape memory alloy wire, it estimates the length of the shape memory alloy wire by deriving the magnitude of the resistance of the shape memory alloy wire.

[0005] However, in the above-described imaging device, if the time for continuously supplying the driving current to the shape memory alloy wire is short, it may not be possible to accurately derive the magnitude of the resistance of the shape memory alloy wire, and there is a risk that the length of the shape memory alloy wire cannot be accurately estimated.

[0006] Therefore, it is desirable to provide an imaging device that can more accurately estimate the length of the shape memory alloy wire.

Means for Solving the Problems

[0007] An imaging apparatus according to one embodiment of the present invention comprises: a fixed side member including a fixed base; a movable side member including a lens holder capable of holding a lens body and movably provided with respect to the fixed side member; a plurality of shape memory alloy wires, one end of which is fixed to the fixed side member and the other end of which is fixed to the movable side member, thereby allowing the movable side member to move; a drive device capable of driving each of the plurality of shape memory alloy wires by supplying a drive current to each of the plurality of shape memory alloy wires; and a control device capable of controlling the drive device by acquiring the resistance value of each of the plurality of shape memory alloy wires. The plurality of shape memory alloy wires include a first wire and a second wire, the first wire being connected to a first conductive member installed on the fixed side member, the second wire being connected to a second conductive member installed on the fixed side member, and the first conductive member and the second conductive member being installed parallel to each other. The control device is The drive current can be simultaneously supplied to the first wire and the second wire, respectively, such that the direction of the drive current flowing through the first conductive member and the direction of the drive current flowing through the second conductive member are opposite to each other. The drive device is controlled so that a measuring current is supplied to each of the multiple shape memory alloy wires at a timing different from the timing at which the driving current is supplied, thereby obtaining the resistance values ​​of the multiple shape memory alloy wires. [Effects of the Invention]

[0008] The imaging device described above can more accurately estimate the length of the shape memory alloy wire. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view of the imaging device. [Figure 2] This is a disassembled perspective view of the imaging device. [Figure 3A] This is a perspective view of a lens holder to which the movable metal member and leaf spring are attached. [Figure 3B] This is a perspective view of the base member to which the fixed metal member is attached. [Figure 4A] This is a side view of a metal component to which a shape memory alloy wire is attached. [Figure 4B] This is a top view of a metal component to which a shape memory alloy wire is attached. [Figure 5] This is a perspective view of the base component. [Figure 6A] This diagram shows the positional relationship between the leaf spring, shape memory alloy wire, metal component, and conductive component. [Figure 6B] It is a diagram showing the positional relationship between the leaf spring and the metal member. [Figure 7A] It is a diagram showing an example of the path of the current flowing through the shape memory alloy wire. [Figure 7B] It is a diagram showing another example of the path of the current flowing through the shape memory alloy wire. [Figure 7C] It is a diagram showing yet another example of the path of the current flowing through the shape memory alloy wire. [Figure 7D] It is a diagram showing yet another example of the path of the current flowing through the shape memory alloy wire. [Figure 7E] It is a diagram showing yet another example of the path of the current flowing through the shape memory alloy wire. [Figure 7F] It is a diagram showing yet another example of the path of the current flowing through the shape memory alloy wire. [Figure 8A] It is a diagram showing an example of the connection structure connecting the fixed-side metal member and the conductive member. [Figure 8B] It is a diagram showing an example of the connection structure connecting the fixed-side metal member and the conductive member. [Figure 9] It is a diagram showing a configuration example of the drive device and the control device. [Figure 10A] It is a diagram showing an example of the path of the current in the drive device. [Figure 10B] It is a diagram showing another example of the path of the current in the drive device. [Figure 10C] It is a diagram showing yet another example of the path of the current in the drive device. [Figure 10D] It is a diagram showing yet another example of the path of the current in the drive device. [Figure 11] It is an example of the timing chart of the drive current and the measurement current flowing through the shape memory alloy wire. [Figure 12A] It is a perspective view of the first conductive member and the second conductive member. [Figure 12B] It is another example of the timing chart of the drive current and the measurement current flowing through the shape memory alloy wire. [Figure 13] It is a diagram showing another configuration example of the drive device. [Modes for carrying out the invention]

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

[0011] In Figures 1 and 2, X1 represents one direction of the X-axis in the three-dimensional Cartesian coordinate system, and X2 represents the other direction of the X-axis. Similarly, Y1 represents one direction of the Y-axis in the three-dimensional Cartesian coordinate system, and Y2 represents the other direction of the Y-axis. Likewise, Z1 represents one direction of the Z-axis in the three-dimensional Cartesian coordinate system, and Z2 represents the other direction of the Z-axis. In Figures 1 and 2, the X1 side of the imaging device 101 corresponds to the front side of the imaging device 101, and the X2 side of the imaging device 101 corresponds to the rear side of the imaging device 101. Furthermore, 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. Furthermore, 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 (image sensor side) of the imaging device 101. The same applies to the other figures.

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

[0013] The cover member 4 is configured to function as a housing that covers other members. In this embodiment, the cover member 4 is made of a non-magnetic metal. However, the cover member 4 may be made of a magnetic metal. Furthermore, the cover member 4 defines a storage section 4S as shown in Figure 1.

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

[0015] As shown in Figure 2, the cover member 4 houses the lens holder 2, metal member 5, leaf spring 6, base member 18, and shape memory alloy wire SA, among other things.

[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 having at least one lens, configured such that its central axis aligns with 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 Figure 2, the lens holder 2 includes a cylindrical portion 2P formed to extend along the optical axis OA, and a movable side base portion 2D and a protruding portion 2S formed to project radially outward from the cylindrical portion 2P. In this embodiment, the lens body is configured to be fixed to the inner circumferential surface of the cylindrical portion 2P with an adhesive.

[0018] The movable side base portion 2D includes a first movable side base portion 2D1 and a second movable side base portion 2D2. The first movable side base portion 2D1 and the second movable side base portion 2D2 are arranged to protrude in opposite directions from each other, straddling 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 to protrude in opposite directions from each other, straddling the optical axis OA. Specifically, the movable side base portion 2D and the protruding portion 2S are arranged to correspond to the four corners of the lens holder 2, which has a substantially rectangular outer shape when viewed from above, and are arranged alternately. A part of the leaf spring 6 is placed on each of the two movable side base 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 the first wire SA1 to the eighth wire SA8. When an electric current flows through the shape memory alloy wire SA, its temperature rises and it contracts in accordance with 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. In this embodiment, the shape memory alloy wire SA is configured such that when one or more of the first wire SA1 to the eighth wire SA8 contract, the lens holder 2 moves, and this movement stretches one or more of the other wires.

[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 from a metal plate mainly composed of, for example, a copper alloy, a titanium-copper alloy (titanium copper), or a copper-nickel alloy (nickel-tin 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 when viewed from above and has an opening 18K in 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 base portion 2D formed on the lens holder 2 and the fixed side base portion 18D formed on the base member 18. The fixed side base portion 18D includes a first fixed side base portion 18D1 and a second fixed side base portion 18D2.

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

[0024] The metal member 5 is configured to hold the end of the shape memory alloy wire SA. In this embodiment, the metal member 5 includes a fixed metal member 5F and a movable metal member 5M. The fixed metal member 5F constitutes a part of the fixed metal member FB and is configured to be fixed to the fixed base portion 18D of the base member 18. The movable metal member 5M constitutes a part of the movable metal member MB and is configured to be fixed to the movable base portion 2D of the lens holder 2.

[0025] More specifically, the fixed-side metal member 5F is also called the 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 called the movable-side terminal plate and includes the first movable-side terminal plate 5M1 to the fourth movable-side terminal plate 5M4.

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

[0027] In the example shown in Figure 3A, the first movable terminal plate 5M1 is fixed to the Y2 side wall (right mounting surface) of the first movable base portion 2D1. Specifically, the first movable terminal plate 5M1 is fixed to the first movable base portion 2D1 by adhesive, with the rectangular projection 2V that protrudes outward (towards the Y2 side) formed on the first movable base portion 2D1 interlocking with the rectangular hole AH (see Figure 4A) formed on the first movable terminal plate 5M1. The adhesive is, for example, a light-curing adhesive. A light-curing adhesive is, for example, an ultraviolet-curing adhesive or a visible-light-curing adhesive. Similarly, the second movable terminal plate 5M2 is fixed to the X2 side wall (rear mounting surface) of the first movable base 2D1, the third movable terminal plate 5M3 is fixed to the X1 side wall (front mounting surface) of the second movable base 2D2, and the fourth movable terminal plate 5M4 is fixed to the Y1 side wall (left mounting surface) of the second movable base 2D2.

[0028] In the example shown in Figure 3B, the first fixed terminal plate 5F1 and the second fixed terminal plate 5F2 are fixed to the Y2 side wall (right mounting surface) of the first fixed base portion 18D1, which is positioned along the second side portion 18E2 of the base member 18. Specifically, the first fixed terminal plate 5F1 and the second fixed terminal plate 5F2 are fixed to the first fixed base portion 18D1 with adhesive. More specifically, the second fixed terminal plate 5F2 is fixed to the first fixed base portion 18D1 with adhesive, with a rectangular projection 18V that protrudes outward (towards the Y2 side) formed on the first fixed base portion 18D1 interlocking with a through hole RH (see Figure 4A) formed on the second fixed terminal plate 5F2. The adhesive is, for example, a light-curing adhesive. A light-curing adhesive is, for example, an ultraviolet-curing adhesive or a visible-light-curing adhesive. Similarly, the third fixed terminal plate 5F3 and the fourth fixed terminal plate 5F4 (invisible in Figure 3B) are fixed to the X2 side wall (rear mounting surface) of the second fixed base portion 18D2, which is positioned along the third side portion 18E3 of the base member 18. The fifth fixed terminal plate 5F5 and the sixth fixed terminal plate 5F6 are fixed to the X1 side wall (front mounting surface) of the first fixed base portion 18D1, which is positioned along the first side portion 18E1 of the base member 18. The seventh fixed terminal plate 5F7 and the eighth fixed terminal plate 5F8 (invisible in Figure 3B) are fixed to the Y1 side wall (left mounting surface) of the second fixed base portion 18D2, which is positioned 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 this embodiment, the shape memory alloy wire SA includes the first wire SA1 to the eighth wire SA8 and is configured to movably support the lens holder 2, which is the movable side member MB, with respect to the base member 18, which is the fixed side member FB. As shown in Figure 2, one end of each of the first wire SA1 to the eighth wire SA8 is fixed to the fixed side metal member 5F by crimping or welding, and the other end is fixed to the movable side metal member 5M by crimping or welding.

[0030] Next, the metal member 5 to which the shape memory alloy wire SA is attached will be described with reference to Figures 4A and 4B. Figure 4A shows the first wire SA1 attached to the first movable terminal plate 5M1 and the first fixed terminal plate 5F1, respectively, and the second wire SA2 attached to the first movable terminal plate 5M1 and the second fixed terminal plate 5F2, respectively, as viewed from the Y2 side. Figure 4B shows the first wire SA1 attached to the first movable terminal plate 5M1 and the first fixed terminal plate 5F1, respectively, and the second wire SA2 attached to the first movable terminal plate 5M1 and the second fixed terminal plate 5F2, respectively, as viewed from the Z1 side. Note that the positional relationship of each member shown in Figures 4A and 4B corresponds to the positional relationship when the imaging device 101 is assembled. In Figures 4A and 4B, other members are omitted from the illustration for clarity. Furthermore, the following explanation, with reference to Figures 4A and 4B, pertains to the combination of the first wire SA1 and the second wire SA2, but it also applies similarly to the combination of the third wire SA3 and the fourth wire SA4, the fifth wire SA5 and the sixth wire SA6, and the seventh wire SA7 and the eighth wire SA8.

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

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

[0033] As shown in Figures 4A and 4B, the first wire SA1 and the second wire SA2 are positioned in a twisted position relative to each other. In other words, the first wire SA1 and the second wire SA2 are positioned so that they do not touch each other (they are non-contact).

[0034] Next, with reference to Figure 5, the details of the base member 18, which is part of the fixed-side member FB, will be described. Figure 5 is a perspective view of the base member 18. Specifically, the upper part of Figure 5 is a perspective view of the base member 18 with the conductive member CM removed, the middle part of Figure 5 is a perspective view of the conductive member CM embedded in the base member 18, and the lower part of Figure 5 is a perspective view of the base member 18 with the conductive member CM embedded. Note that in the middle and lower parts of Figure 5, a dot pattern has been added 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 wires SA1 to the eighth wires SA8. With this configuration, the movable side member MB is supported by the first wires SA1 to the eighth wires SA8 in a manner that allows it to move in the Z-axis direction, which is parallel to the optical axis OA.

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

[0037] A conductive member CM, formed from a metal plate containing copper, iron, or an alloy mainly composed of these materials, is embedded in the base member 18 by insert molding, as shown in the center view of Figure 5. In this embodiment, the conductive member CM is configured to have first terminal portions TM1 to sixth terminal portions TM6 that are exposed from the front (X1 side) and rear (X2 side) surfaces of the base member 18 and extend downward (in the Z2 direction), and fifth and sixth bonding surface portions CP5 and CP6 that are exposed on the upper surface (Z1 side) of the base member 18.

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

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

[0040] Furthermore, the first connection portion ED1 of the first conductive member CM1 is positioned along the second side portion 18E2 of the base member 18, and the first terminal portion TM1 of the first conductive member CM1 is positioned along the third side portion 18E3 of the base member 18, rather than the second side portion 18E2. Similarly, the second connection portion ED2 of the second conductive member CM2 is positioned along the second side portion 18E2 of the base member 18, and the second terminal portion TM2 of the second conductive member CM2 is positioned along the third side portion 18E3 of the base member 18, rather than the second side portion 18E2.

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

[0042] Thus, the first to sixth terminals TM1 to TM6 are arranged along the first or third side 18E1 or 18E3 of the base member 18, and not along the second or fourth side 18E2 or 18E4 of the base member 18. This is to facilitate the mounting of the image sensor. Specifically, this is to ensure that the flexible printed circuit board or the like connected to the image sensor is positioned so that it passes under at least one of the second or fourth side 18E2 or 18E4 of the base member 18.

[0043] Next, the positional relationships of the leaf spring 6, shape memory alloy wire SA, metal member 5, and conductive member CM will be explained with reference to Figures 6A and 6B. Figure 6 is a diagram showing the positional relationships of the leaf spring 6, shape memory alloy wire SA, metal member 5, and conductive member CM. Specifically, Figure 6A is a perspective view of the metal member 5, leaf spring 6, shape memory alloy wire SA, and conductive member CM, and Figure 6B is a top view of the metal member 5 and leaf spring 6. Note that in Figure 6B, the shape memory alloy wire SA and conductive member CM are omitted for clarity. Also, in Figures 6A and 6B, a dot pattern is added to the leaf spring 6 for clarity.

[0044] As shown in Figure 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 base portion 18D1 (see Figure 2) of the base member 18, a second portion 6A2 fixed to the second fixed side base portion 18D2 (see Figure 2) of the base member 18, a third portion 6A3 fixed to the first movable side base portion 2D1 (see Figure 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] The first part 6A1 has a first through hole 6AH1 and a second through hole 6AH2 through which a round projection 18T (see Figure 3B) that protrudes upward, formed on the first fixed side base part 18D1, is inserted. In this embodiment, the leaf spring 6 and the projection 18T are fixed together by heat riveting or cold riveting of the projection 18T. However, the leaf spring 6 and the projection 18T may also be fixed together by adhesive.

[0046] The second portion 6A2 has a third through-hole 6AH3 through which an upwardly projecting round projection 18T (see Figure 3B) formed on the second fixed-side base portion 18D2 is inserted, and a fourth through-hole 6AH4 used for joining the sixth joining surface portion CP6 (see lower diagram in Figure 5) of the sixth conductive member CM6. In this embodiment, the joining of the leaf spring 6 and the conductive member CM is achieved by welding, such as laser welding. However, the joining of the leaf spring 6 and the conductive member CM may also be achieved by solder or conductive adhesive.

[0047] The third portion 6A3 has a fifth through hole 6AH5 and a sixth through hole 6AH6 through which an upwardly projecting round projection 2T (see Figure 3A) formed on the first movable side base portion 2D1 is inserted. In this embodiment, the leaf spring 6 and the projection 2T are fixed together by heat riveting or cold riveting of the projection 2T. However, the leaf spring 6 and the projection 2T may also be fixed together by adhesive.

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

[0049] The first part 6B1 has a first through hole 6BH1 through which an upwardly projecting round projection 18T (see Figure 3B) formed on the first fixed base portion 18D1 is inserted, and a second through hole 6BH2 used for joining the fifth bonding surface portion CP5 (see lower diagram in Figure 5) of the fifth conductive member CM5.

[0050] The second part 6B2 has a third through hole 6BH3 and a fourth through hole 6BH4 through which an upwardly projecting round projection 18T (see Figure 3B) formed in the second fixed base part 18D2 is inserted.

[0051] The third portion 6B3 has a fifth through hole 6BH5 and a sixth through hole 6BH6 through which an upwardly projecting, round projection 2T (see Figure 3A) formed in the second movable side base portion 2D2 is inserted.

[0052] The fourth portion 6A4 and the fifth portion 6A5 of the first leaf spring 6A, and the fourth portion 6B4 and the fifth portion 6B5 of the second leaf spring 6B are elastically deformable arms having multiple bends. 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, relative to the base member 18 (fixed side member FB).

[0053] As shown in Figure 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 symmetrical twice with respect to the optical axis OA. Therefore, this configuration can reduce the number of parts in 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 balanced manner in the air. Furthermore, the leaf springs 6 do not adversely affect the weight balance of the movable side member MB, which is supported by eight shape memory alloy wires SA (first wire SA1 to eighth wire SA8).

[0054] As shown in Figure 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 bonding material SD. The bonding material SD is, for example, solder or 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 a bonding 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 a bonding 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 a bonding material SD. In Figures 6A and 6B, the bonding material SD is represented by a dashed circle for clarity.

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

[0056] On the other hand, as shown in Figure 6B, the first fixed terminal plate 5F1 is positioned at a distance 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 terminal plate 5F3 does not contact the second portion 6A2 of the first leaf spring 6A, the fifth fixed terminal plate 5F5 does not contact the first portion 6B1 of the second leaf spring 6B, and the seventh fixed terminal plate 5F7 does not contact the second portion 6B2 of the second leaf spring 6B.

[0057] The fifth joining surface CP5 of the fifth conductive member CM5 (see the center view in Figure 5) is joined to the first portion 6B1 of the second leaf spring 6B 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 joining surface CP5 and the first portion 6B1 are joined with their surfaces substantially parallel to each other. Similarly, the sixth joining surface CP6 of the sixth conductive member CM6 (see the center view in Figure 5) is joined to the second portion 6A2 of the first leaf spring 6A 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, the current path through the shape memory alloy wire SA will be explained with reference to Figures 7A to 7F. Figures 7A to 7F are diagrams of parts of the configuration shown in Figure 6A. In Figures 7A to 7F, dot patterns are added to the components through which the current flows for clarity. Specifically, in Figure 7A, the first conductive member CM1 and the second conductive member CM2 are marked with coarse dot patterns, while the first movable terminal plate 5M1, the first fixed terminal plate 5F1, and the second fixed terminal plate 5F2 are marked with fine dot patterns. In Figure 7B, the first conductive member CM1 and the sixth conductive member CM6 are marked with coarse dot patterns, the first leaf spring 6A is marked with fine dot patterns, and the first movable terminal plate 5M1 and the first fixed terminal plate 5F1 are marked with even finer dot patterns. Furthermore, in Figure 7C, the second conductive member CM2 and the sixth conductive member CM6 are given a coarse dot pattern, the first leaf spring 6A is given a fine dot pattern, and the first movable terminal plate 5M1 and the second fixed terminal plate 5F2 are given an even finer dot pattern. Furthermore, in Figure 7D, the second movable terminal plate 5M2, the third fixed terminal plate 5F3, and the fourth fixed terminal plate 5F4 are given a fine dot pattern. Furthermore, in Figure 7E, the sixth conductive member CM6 is given a coarse dot pattern, the first leaf spring 6A is given a fine dot pattern, and the second movable terminal plate 5M2 and the third fixed terminal plate 5F3 are given an even finer dot pattern. Furthermore, in Figure 7F, the sixth conductive member CM6 is given a coarse dot pattern, the first leaf spring 6A is given a fine dot pattern, and the second movable terminal plate 5M2 and the fourth fixed terminal plate 5F4 are given an even finer dot pattern.

[0059] Specifically, Figure 7A shows the current path when the first terminal TM1 of the first conductive member CM1 is connected to a high potential and the second terminal TM2 of the second conductive member CM2 is connected to a low potential. Figure 7B shows the current path when the first terminal TM1 of the first conductive member CM1 is connected to a high potential and the sixth terminal TM6 of the sixth conductive member CM6 is connected to a low potential. Figure 7C shows the current path when the second terminal TM2 of the second conductive member CM2 is connected to a high potential and the sixth terminal TM6 of the sixth conductive member CM6 is connected to a low potential. The following explanation, referring to Figures 7A to 7C, concerns the current path flowing through the first wire SA1 or the second wire SA2, but it also applies 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, current flows from the first terminal portion TM1 through the first conductive member CM1 to the first fixed terminal plate 5F1, as indicated by arrow AR1 in Figure 7A. Subsequently, the current flows through the first fixed terminal plate 5F1, as indicated by arrow AR2, through the first wire SA1, as indicated by arrow AR3, and further through the first movable terminal plate 5M1, as indicated by arrow AR4. After that, the current flows through the second wire SA2, as indicated by arrow AR5, through the second fixed terminal plate 5F2, as indicated by arrow AR6, and then through the second conductive member CM2 to the second terminal portion TM2, as indicated by 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 terminal plate 5F1, as indicated by arrow AR11 in Figure 7B. Subsequently, the current passes through the first fixed terminal plate 5F1, as indicated by arrow AR12, through the first wire SA1, as indicated by arrow AR13, and further through the first movable terminal plate 5M1, as indicated by arrow AR14. After that, 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 to the sixth terminal portion TM6, as indicated by arrows AR16 and AR17.

[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 terminal plate 5F2, as indicated by arrow AR21 in Figure 7C. Subsequently, the current passes through the second fixed terminal plate 5F2, as indicated by arrow AR22, through the second wire SA2, as indicated by arrow AR23, and further through the first movable terminal plate 5M1, as indicated by arrow AR24. After that, 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 to the sixth terminal portion TM6, as indicated by arrows AR26 and AR27.

[0063] Figure 7D also shows the current path when the third contact CT3 of the third fixed terminal plate 5F3 is connected to a high potential and the fourth contact CT4 of the fourth fixed terminal plate 5F4 is connected to a low potential. Figure 7E shows the current path when the third contact CT3 of the third fixed terminal plate 5F3 is connected to a high potential and the sixth terminal TM6 of the sixth conductive member CM6 is connected to a low potential. Figure 7F shows the current path when the fourth contact CT4 of the fourth fixed terminal plate 5F4 is connected to a high potential and the sixth terminal TM6 of the sixth conductive member CM6 is connected to a low potential. The following explanation, referring to Figures 7D to 7F, concerns the current path flowing through the third wire SA3 or the fourth wire SA4, but the same applies to the current path flowing through the fifth wire SA5 or the sixth wire SA6.

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

[0065] When the third contact portion CT3 of the third fixed 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 terminal plate 5F3, as indicated by arrow AR41 in Figure 7E. Subsequently, the current flows through the third wire SA3, as indicated by arrow AR42, through the second movable terminal plate 5M2, as indicated by arrow AR43, and further through the third portion 6A3, fifth portion 6A5, and second portion 6A2 of the first leaf spring 6A, as indicated by arrow AR44. Subsequently, the current flows from the sixth bonding surface portion CP6 to the sixth terminal portion TM6 through the sixth conductive member CM6, as indicated by arrow AR45.

[0066] When the fourth contact portion CT4 of the fourth fixed 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 terminal plate 5F4, as indicated by arrow AR51 in Figure 7F. Subsequently, the current flows through the fourth wire SA4, as indicated by arrow AR52, through the second movable terminal plate 5M2, as indicated by arrow AR53, and further through the third portion 6A3, fifth portion 6A5, and second portion 6A2 of the first leaf spring 6A, as indicated by arrow AR54. Subsequently, 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 arrow AR55.

[0067] Next, an example of a connection structure for connecting the fixed metal member 5F and the conductive member CM will be described with reference to Figures 8A and 8B. Figures 8A and 8B show an example of a connection structure for connecting the fixed metal member 5F and the conductive member CM. Specifically, Figure 8A is an enlarged view (perspective view) of the area R1 enclosed by the dashed line shown in Figure 3B. Figure 8B is a right side view of the area R1 enclosed by the dashed line shown in Figure 3B. Note that in Figures 8A and 8B, a fine dot pattern is applied to the base member 18 for clarity.

[0068] As shown in Figures 8A and 8B, the first fixed terminal plate 5F1 is attached to the Y2 side wall (right mounting surface) of the first fixed base portion 18D1 of the base member 18 using a light-curing adhesive. The first contact portion CT1 of the first fixed terminal plate 5F1 is joined to the first connection portion ED1 of the first conductive member CM1 via a bonding material SD. In Figures 8A and 8B, a cross pattern is applied to the bonding material SD for clarity.

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

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

[0071] This arrangement allows the bonding material SD to adhere to at least the front surface (X1 side) of the first connection part ED1 and the rear surface (X2 side) and top surface (Z1 side) of the first contact part CT1, thereby increasing the connection strength of the bonding material SD between the first contact part CT1 and the first connection part ED1. The same applies to the connection strength of the bonding material SD between the second contact part CT2 and the second connection part ED2.

[0072] Furthermore, this arrangement prevents the first contact portion CT1 from being joined only to the right end face (Y2 side face) of the first connection portion ED1, which is not plated, by the joining material SD. The same applies to the joining between the second connection portion ED2 and the second contact portion CT2. Note that the right end face (Y2 side face) of the first connection portion ED1 is the cut surface formed when the unillustrated cut-off connection portion is separated, and therefore is not plated. The cut-off connection portion is a part used to connect multiple conductive members and is used when multiple conductive members are embedded in the base member 18 by insert molding, but is ultimately cut off.

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

[0074] The drive unit 10 is configured to drive each of the multiple shape memory alloy wires SA by supplying a drive current to each of the multiple shape memory alloy wires SA. The drive current is a current used to drive (heat and shrink) the shape memory alloy wires SA, and is, for example, a pulse current. In this embodiment, the drive unit 10 is an electronic circuit composed of active elements AE such as switching elements, operational amplifiers, or ICs, and is configured to operate in response to a control signal from the control device 20.

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

[0076] The control device 20 is configured to control the drive device 10. In this embodiment, the control device 20 is a microcomputer equipped with a CPU, a volatile memory device, and a non-volatile memory device, etc.

[0077] In the illustrated example, the control device 20 can control the drive device 10 to move the lens holder 2 along the direction parallel to the optical axis OA on the Z1 side (subject side) of the image sensor by utilizing the driving force along the direction parallel to the optical axis OA caused by the contraction of the shape memory alloy wire SA. 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 achieve macro photography by moving the lens holder 2 away from the image sensor, and achieve infinity focus photography by moving the lens holder 2 closer to the image sensor.

[0078] Furthermore, 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 multiple shape memory alloy wires SA. This enables the control device 20 to implement an image stabilization function.

[0079] In the illustrated example, the imaging device 101, which has a roughly rectangular parallelepiped shape, is mounted on an external substrate (not shown) on which an image sensor (not shown) is mounted. The camera module consists of, for example, the external substrate, the imaging device 101, a lens body mounted on the lens holder 2, and an image sensor positioned opposite the lens body. The drive unit 10 and the control unit 20 are mounted on the external substrate. However, at least one of the drive unit 10 and the control unit 20 may be located inside the imaging device 101. The image sensor may also be mounted on the imaging device 101.

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

[0081] The measuring current is a current used to measure the resistance between the ends of the shape memory alloy wire SA. Preferably, the measuring current is a weak current that does not affect the length of the shape memory alloy wire SA, for example, a pulsed current. In the illustrated example, the control device 20 can derive the magnitude of the resistance between the ends of the shape memory alloy wire SA (measured resistance value) by measuring the voltage between the ends of the shape memory alloy wire SA when a measuring current of known magnitude is passed through the shape memory alloy wire SA. The measured resistance values ​​of each of the eight shape memory alloy wires SA are then used to achieve a desired posture of the lens holder 2 (lens body). For example, the control device 20 can set a target length for each of the eight shape memory alloy wires SA corresponding to the desired posture of the lens holder 2 (lens body), and further, it can set a target resistance value for each of the eight shape memory alloy wires SA corresponding to each of those eight target lengths. Then, the control device 20 can achieve the desired posture of the lens holder 2 (lens body) by controlling the drive 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. Furthermore, since the measurement current is a very weak current that does not affect the length of the shape memory alloy wire SA, its magnitude is significantly smaller than that of the driving 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 achieve the desired orientation of the lens holder 2 (lens body). The control device 20 then controls the drive device 10 so that the measured resistance value of each of the eight shape memory alloy wires SA is the same as the target resistance value. In other words, the control device 20 performs feedback control of the resistance values ​​of each of the eight shape memory alloy wires SA.

[0083] Specifically, the control device 20 controls the drive device 10 for each of the eight shape memory alloy wires SA 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 driving current supplied to each of the eight shape memory alloy wires SA. In the illustrated example, if the target resistance value of a particular shape memory alloy wire SA is smaller than the measured resistance value, the control device 20 increases the amount of power supplied to that particular shape memory alloy wire SA in order to contract it. For example, the control device 20 lengthens the supply time of the driving current, i.e., the time during which a predetermined voltage is applied across both ends of that particular shape memory alloy wire SA. Conversely, if the target resistance value of a particular shape memory alloy wire SA is larger than the measured resistance value, the control device 20 reduces the amount of power supplied to that particular shape memory alloy wire SA and increases the amount of power supplied to other shape memory alloy wires SA in order to stretch that particular shape memory alloy wire SA. For example, the control device 20 increases the time during which a predetermined voltage is applied between the ends of a shape memory alloy wire SA other than the specific shape memory alloy wire SA.

[0084] Specifically, the first drive unit 10A includes a high-potential source 11, a low-potential source 12, a constant-current source 13, and an active element AE, as shown in Figure 9. The following description, referring to Figure 9, pertains to the first drive unit 10A, but also applies to the second drive unit 10B.

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

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

[0087] Although the potentials of both the high-potential source 11 and the low-potential source 12 are fixed, at least one of the high-potential source 11 and the low-potential source 12 may be configured to dynamically change its potential in response to a control signal from the control device 20.

[0088] The constant current source 13 is an electrical circuit that can supply a current of a constant magnitude even when the resistance value of the load changes. In the illustrated example, the constant current source 13 is configured to supply a measuring current of a constant magnitude to each of the first wire SA1 to the fourth wire SA4. The magnitude of the measuring current is set, for example, by the control device 20. In this case, the magnitude of the measuring current may be stored in a non-volatile memory device in the control device 20. For example, the magnitude of the measuring current may be set based on the results of factory inspections performed at the time of shipment of the product (imaging device 101) so as to suit 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] An active element AE is an element that performs active operations such as amplification or rectification using 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 a single output. In the illustrated example, the three inputs of the first active element AE1 are connected to a high-potential source 11, a low-potential source 12, and a 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 combines two inputs into a single output. In the illustrated example, the two inputs of the third active element AE3 are connected to the second active element AE2 and to 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 combines two inputs into a single output. In the illustrated example, the two inputs of the fourth active element AE4 are connected to the second active element AE2 and to 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 output. In the illustrated example, the input of the fifth active element AE5 is connected to a common conductive path CD0, which is a conductive path connected to the first wire SA1, the second wire SA2, the third wire SA3, and the fourth wire SA4, respectively, and one output of the fifth active element AE5 is connected to 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 conductive 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 conductive path CD0, and one output of the sixth active element AE6 is connected to the control device 20.

[0096] 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. Similarly, 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. Furthermore, 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. Finally, 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 Figure 7A, the first conductive path CD1 includes the first fixed terminal plate 5F1, and the second conductive path CD2 includes the second fixed terminal plate 5F2. Also, as shown in Figure 7D, the third conductive path CD3 includes the third fixed terminal plate 5F3, and the fourth conductive path CD4 includes the fourth fixed terminal plate 5F4. Furthermore, as shown in Figures 7B, 7C, 7E, and 7F, the common conductive path CD0 includes the first movable terminal plate 5M1, the second movable terminal plate 5M2, the first leaf spring 6A (third portion 6A3, fifth portion 6A5, and second portion 6A2), and the sixth conductive member CM6.

[0098] In other words, as shown in Figures 7A to 7F, the first drive unit 10A can control the contraction of the first wire SA1 to the fourth wire SA4 by controlling the voltage applied to the first terminal TM1, the second terminal TM2, the sixth terminal TM6, the third contact CT3, and the fourth contact CT4, respectively. The same applies to the second drive unit 10B.

[0099] Furthermore, in the illustrated example, when the first drive unit 10A supplies current to the third wire SA3 and the fourth wire SA4, it does not use the long conductive paths (first conductive member CM1 and second conductive member CM2 extending along the opening 18K of the base member 18) that are used when supplying current to the first wire SA1 and the second wire SA2, respectively. Therefore, this configuration has the effect of reducing the magnetic field (induced magnetic field) formed around the conductive path, which can adversely affect the image quality of the image sensor, when supplying current to the third wire SA3 and the fourth wire SA4, respectively. In other words, this configuration has the effect of relaxing the restrictions on the magnitude of the current flowing through the third wire SA3 and the fourth wire SA4, respectively, compared to the restrictions on the magnitude of the current flowing through the first wire SA1 and the second wire SA2, respectively.

[0100] Furthermore, in the illustrated example, the first drive unit 10A and the second drive unit 10B are configured to share a high potential source 11, a low potential source 12, and a constant current source 13, respectively. However, they may be configured to individually provide 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 drive unit 10A and a second constant current source connected to the first active element (not shown) of the second drive unit 10B.

[0101] Furthermore, in the illustrated example, the drive unit 10 is configured to be connected to both the high-potential source 11 and the low-potential source 12, but it may also 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] In the illustrated example, the drive unit 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 a measurement current is passed through the shape memory alloy wire SA. However, the constant current source 13 may be omitted. In this case, the drive unit 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 unit 10 may include a shunt resistor for measuring the magnitude of the measurement current flowing through the shape memory alloy wire SA.

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

[0104] Next, with reference to Figures 10A to 10D, we will explain examples of current paths flowing through the shape memory alloy wire SA. Figures 10A to 10D are diagrams showing examples of current paths in the drive device 10 and correspond to Figure 9. In Figures 10A to 10D, for clarity, conductive paths through which current is flowing are represented by thick solid lines, and conductive paths through which no current is flowing are represented by dashed lines.

[0105] Figure 10A shows an example of the path of the drive current flowing through two shape memory alloy wires SA (first wire SA1 and second wire SA2) that are electrically connected in series. The drive current path shown in Figure 7A is one specific example of the drive current path shown in Figure 10A. Specifically, Figure 10A shows the path of the drive 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 fixed-side terminal plate 5F1 in Figure 7A, the second conductive path CD2 is realized by the second fixed-side terminal plate 5F2 in Figure 7A, and the common conductive path CD0 is realized by the first movable-side terminal plate 5M1.

[0106] Figure 10B shows an example of the path of the drive current flowing through a single shape memory alloy wire SA (first wire SA1). The drive current path shown in Figure 7B is one specific example of the drive current path shown in Figure 10B. Specifically, Figure 10B shows the path of the drive 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 fixed-side terminal plate 5F1 in Figure 7B, and the common conductive path CD0 is realized by the first movable-side terminal plate 5M1, the first leaf spring 6A (third part 6A3, fifth part 6A5, and second part 6A2), and the sixth conductive member CM6 in Figure 7B.

[0107] Figure 10C shows another example of the path of the drive current flowing through a single shape memory alloy wire SA (second wire SA2). The drive current path shown in Figure 7C is one specific example of the drive current path shown in Figure 10C. Specifically, Figure 10C shows the path of the drive 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 Figure 7C, and the common conductive path CD0 is realized by the first movable-side terminal plate 5M1, the first leaf spring 6A (third part 6A3, fifth part 6A5, and second part 6A2), and the sixth conductive member CM6 in Figure 7C.

[0108] Figure 10D shows an example of the path of a measuring current flowing through a single shape memory alloy wire SA (first wire SA1). The current path shown in Figure 7B is one specific example of the current path shown in Figure 10D. Specifically, Figure 10D shows the path of the measuring 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 fixed-side terminal plate 5F1 in Figure 7B, and the common conductive path CD0 is realized by the first movable-side terminal plate 5M1, the first leaf spring 6A (third part 6A3, fifth part 6A5, and second part 6A2), and the sixth conductive member CM6 in Figure 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, acting 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 magnitude of the resistance 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 similarly calculate the magnitude of the resistances of the second wire SA2 to the fourth wire SA4.

[0110] Next, with reference to Figure 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. Figure 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, Figure 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 temporal change of the voltage applied to each of the first wire SA1 to the fourth wire SA4. The following explanation with reference to Figure 11 concerns 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 it can also be similarly applied 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 Figure 11, the control of the drive device 10 by the control device 20 is achieved by pulse width modulation. However, the control of the drive device 10 by the control device 20 may also be achieved by other methods such as pulse amplitude modulation.

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

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

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

[0115] The first measurement time slot M1 is a time slot pre-set as the period during which measurement current can be supplied to the first wire SA1. During the period of the first measurement time slot M1, no drive current is supplied to the first wire SA1 to the fourth wire SA4. Therefore, during the period of the first measurement time slot M1, if a pulse width modulation method is employed, it is also called the "PWM OFF period". The same applies to the second measurement time slots M2 to the fourth measurement time slots M4. In the illustrated example, the drive device 10 is configured such that the magnitude (duration) of each of the first measurement time slots M1 to the fourth measurement time slots M4 is the same. However, the drive device 10 may be configured such that the magnitude (duration) of each of the first measurement time slots M1 to the fourth measurement time slots 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 than the duration of the measurement time slot.

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

[0117] In the illustrated example, the control device 20 controls the drive device 10 so that the first measurement time slot M1 is set after the first drive time slots D1 to D4 in the first drive cycle. However, the drive device 10 may be controlled so that the first measurement time slot is set between the two drive time slots. For example, the control device 20 may control the drive device 10 so 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] In the illustrated example, the control device 20 controls the drive device 10 so that a combination of the first drive cycle, second drive cycle, third drive cycle, and fourth drive cycle constitutes one measurement cycle. That is, the control device 20 controls the drive device 10 so that the resistance magnitude of each of the four shape memory alloy wires SA (first wire SA1 to fourth wire SA4) can be obtained by executing one measurement cycle.

[0119] In the illustrated example, the control device 20 controls the drive device 10 so that the four drive cycles are executed in the order of the first drive cycle, the second drive cycle, the third drive cycle, and the fourth drive cycle. However, the drive device 10 may be controlled to execute the four drive cycles in any other order.

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

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

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

[0123] The duration E5 for which the measurement current flows through the first wire SA1 is set according to the conversion speed of the AD converter used to convert the analog signal output by the sixth active element AE6, which acts 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 a longer duration, that is, sets the measurement time to a longer duration, it can accurately obtain the resistance of the four shape memory alloy wires SA even if it uses an AD converter with a slow conversion speed.

[0124] Furthermore, in a configuration in which the resistance of the first wire SA1 is measured while a drive current flows through the first wire SA1, the duration E1 for which the drive current flows through the first wire SA1 must 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, the duration E1 does not necessarily have to be greater than or equal to the duration E5. That is, the control device 20 can adopt a duration E1 that is shorter than the duration E5 for which the measurement current flows through the first wire SA1. The same applies to the second wire SA2 to the fourth wire SA4.

[0125] Furthermore, in the illustrated example, the drive unit 10 includes a first drive unit 10A configured to drive each of the first wires SA1 to the fourth wire SA4, and a second drive unit 10B configured to drive each of the fifth wires SA5 to the eighth wire SA8. In other words, the imaging device 101 is configured to have two drive units capable of driving four shape memory alloy wires SA. This configuration, compared to a configuration with only one drive unit capable of driving eight shape memory alloy wires SA, allows for a larger drive time slot that can be allocated to a single shape memory alloy wire SA, reduces the magnitude of the current required to supply a desired amount of power to a single shape memory alloy wire SA, and consequently reduces the magnetic field formed around the conductive path. However, the imaging device 101 may also be configured to have only one drive unit capable of driving eight shape memory alloy wires SA. In this case, the control device 20 may, for example, control that single drive unit so that one measurement cycle consists of eight drive cycles, and one drive cycle consists 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 to include eight drive devices capable of driving one shape memory alloy wire SA.

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

[0127] Next, with reference to Figures 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. Figure 12A is a perspective view of the first conductive member CM1, which constitutes part of the first conductive path CD1 (see Figure 9), and the second conductive member CM2, which constitutes part of the second conductive path CD2 (see Figure 9). Figure 12B is another example of a timing chart of the driving current and the measuring current flowing through the first wire SA1 to the fourth wire SA4, and corresponds to Figure 11. Specifically, Figure 12B shows the timing relationship between the driving current and the measuring current flowing through the first wire SA1 to the fourth wire SA4 by showing the temporal change of the voltage applied to each of the first wire SA1 to the fourth wire SA4. The following explanation with reference to Figure 12A concerns the currents flowing through the first conductive member CM1 and the second conductive member CM2, respectively, but it also applies similarly to the currents flowing through the third conductive member CM3 and the fourth conductive member CM4, respectively. Furthermore, the following explanation, with reference to Figures 12A and 12B, pertains to the timing relationship between the driving current and measuring current flowing through the first wire SA1 to the fourth wire SA4, but it also applies similarly to the timing relationship between the driving current and measuring current flowing through the fifth wire SA5 to the eighth wire SA8.

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

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

[0130] More specifically, as shown in Figure 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 ground (GND) in series, thereby controlling the drive 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 arrow AR61 in Figure 12A, the control device 20 controls the drive device 10 so that current flows from the first point PT1 to the second point PT2 of the first conductive path CD1 (first conductive member CM1), and simultaneously, as indicated by arrow AR62 in Figure 12A, current flows from the second point PT12 to the first point PT11 of the second conductive path CD2 (second conductive member CM2). Hereafter, the operating mode of the drive device 10 at this time will be referred to as "first mode," and the state of the imaging device 101 at this time will be referred to as "high-power drive state." Furthermore, this state is also called the "common drive state" because the first wire SA1 and the second wire SA2 are driven simultaneously.

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

[0132] Furthermore, the control device 20 causes the drive unit 10 to execute the "first mode" which realizes a "common drive state," thereby providing the effect of making the "PWM OFF period" longer when a pulse width modulation method is used, compared to when the "first mode" is not executed.

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

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

[0135] More specifically, as shown in Figure 10B, the control device 20 electrically connects the low potential source 12, the first conductive path CD1, the first wire SA1, the common conductive path CD0, and ground (GND) in series, thereby controlling the drive device 10 so that a relatively small current is supplied to the first wire SA1. That is, as indicated by the arrow AR61 in Figure 12A, the control device 20 controls the drive device 10 so that 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). Hereafter, the operating mode of the drive device 10 at this time will be referred to as the "second mode," and the state of the imaging device 101 at this time will be referred to as the "weak drive state" or "first weak drive state."

[0136] In the example shown in Figure 12B, the sum of the amount of power supplied to the first wire SA1 during the "strong drive state" of the first drive cycle and the amount of power supplied to the first wire SA1 during 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 for the duration of the first drive time slot D1. Figure 12B shows the voltage waveform as a dotted line if the high potential source 11 and the first wire SA1 were connected for the duration of the first drive time slot D1.

[0137] Furthermore, in the "first weak drive state," the magnitude of the current flowing through the first conductive path CD1 (first conductive member CM1) is smaller compared to the "strong drive state," and therefore the magnitude of the magnetic field formed around the first conductive path CD1 (first conductive member CM1) is also reduced. As a result, even if no current is supplied to the second conductive path CD2 (second conductive member CM2) and no magnetic field is formed that cancels out the magnetic field formed around the first conductive path CD1 (first conductive member CM1), the amount by which the magnitude of the current flowing through the first conductive path CD1 (first conductive member CM1) is reduced will decrease the magnetic field (induced magnetic field) that could adversely affect the image quality of the image sensor.

[0138] Furthermore, the control device 20 may control the drive device 10 so that the drive current flows only through the second wire SA2 after causing the drive device 10 to execute the "first mode" during the remaining period of the combined period of the first drive time slot D1 and the second drive time slot D2, that is, during the combined period of the first drive time slot D1 and the second drive time slot D2.

[0139] More specifically, the control device 20 may control the drive device 10 so that a relatively small current is supplied to the second wire SA2 by electrically connecting the low potential source 12, the second conductive path CD2, the second wire SA2, the common conductive path CD0, and ground (GND) in series, as shown in Figure 10C. That is, the control device 20 may control the drive device 10 so 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 to the first conductive path CD1 (first conductive member CM1). Hereinafter, the operating mode of the drive device 10 in this case will be referred to as the "third mode," and the state of the imaging device 101 in this case will be referred to as the "weak drive state" or "second weak drive state."

[0140] Furthermore, the control device 20 may control the drive device 10 to execute the "first mode" and the "second mode" during the period when the first drive time slot D1 and the second drive time slot D2 are combined, and then execute the "third mode". For example, the control device 20 may control the drive device 10 so that the drive current flows only through the second wire SA2 for a period from time tf to time tg, that is, for a period E13 shorter than the duration of the second drive time slot D2. This is for example, to fine-tune the amount of power supplied to the second wire SA2. Figure 12B shows the voltage waveform with a dotted line when the low potential source 12 and the second wire SA2 are connected for a period from time tf to time tg.

[0141] Furthermore, when the drive unit 10 is made to execute the "second mode" or "third mode," the state of the imaging device 101 is also referred to as the "individually driven state," since the first wire SA1 or the second wire SA2 are driven individually.

[0142] The control device 20 can supply a desired amount of 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 that combines the "first mode" with the "second mode" or the "third mode". The "first mode" for the first wire SA1 and the second wire SA2 can be more effective when the amount of power to be supplied to the first wire SA1 and the amount of power to be supplied to the second wire SA2 are large and the difference between them is small. This is because a large amount of power can be supplied to each of the first wire SA1 and the second wire SA2 in a short time while suppressing adverse effects on the image quality of the image sensor. Furthermore, the larger the difference between the amount of power to be supplied to the first wire SA1 and the amount of power to be supplied to the second wire SA2, the more dominant the "second mode" or "third mode" becomes in the time axis. However, the control device 20 can reduce adverse effects on the image quality of the image sensor by maximizing the duration of the "second mode" or "third mode". This is because the current flowing through the first conductive path CD1 (first conductive member CM1) or the second conductive path CD2 (second conductive member CM2) can be reduced, and the magnetic field formed around the first conductive path CD1 (first conductive member CM1) or the second conductive path CD2 (second conductive member CM2) can be reduced.

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

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

[0145] Next, with reference to Figure 13, another example of the configuration of the drive unit 10 will be described. Figure 13 is a diagram showing another example of the configuration of the drive unit 10. The following description with reference to Figure 13 pertains to the first drive unit 10A, which is configured to drive each of the first wires SA1 to the fourth wire SA4, but it also applies similarly to the second drive unit 10B, which is configured to drive each of the fifth wires SA5 to the eighth wire SA8. In addition, for clarity, the diagram of the configuration of active elements, etc., for estimating the resistance values ​​of each of the first wires SA1 to the fourth wire SA4 is omitted in Figure 13, but such a configuration is actually connected.

[0146] The first drive unit 10A shown in Figure 13 differs from the first drive unit 10A shown in Figure 9 in that it includes five active elements AE (10th active element AE10 to 14th active element AE14).

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

[0148] The 11th active element AE11 is a switching element that controls the connection between the first conductive path CD1, which is connected to one end of the first wire SA1, and either a high potential source (HIGH) or a low potential source (LOW).

[0149] The 12th active element AE12 is a switching element that controls the connection between the second conductive path CD2, which is connected to one end of the second wire SA2, and ground (GND).

[0150] The 13th active element AE13 is a switching element that controls the connection between the third conductive path CD3, which is connected to one end of the third wire SA3, and either a high potential source (HIGH) or a low potential source (LOW).

[0151] The 14th active element AE14 is a switching element that controls the connection between the 4th conductive path CD4, which is connected to one end of the 4th wire SA4, and 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 11th active element AE11 and the 12th 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. Furthermore, the control device 20 can supply a relatively small current to only the first wire SA1 by controlling the 10th active element AE10 and the 11th 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. Furthermore, the control device 20 can supply a relatively small current only to the second wire SA2 by controlling the 10th active element AE10 and the 12th 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 13th active element AE13 and the 14th 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. In addition, the control device 20 can supply a relatively small current to only the third wire SA3 by controlling the 10th active element AE10 and the 13th 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. Furthermore, the control device 20 can supply a relatively small current only to 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] Furthermore, in the example shown in Figure 13, the high potential source (HIGH) has a fixed potential, but it may be configured to dynamically change its potential in response to a control signal from the control device 20. Conversely, the low potential source (LOW) is configured to dynamically change its potential in response to a control signal from the control device 20, but its potential may also be fixed.

[0155] Alternatively, the drive device 10 shown in Figure 13 may be configured such that, with the common conductive path CD0 to which the other ends of the first wire SA1 to the fourth wire SA4 are connected, is connected to a potential source having a potential of 3V or the like, one end of each of the first wire SA1 to the fourth wire SA4 can be selectively connected to ground (GND) via an active element such as an N-channel transistor.

[0156] Even with such configurations, the drive unit 10 can execute a composite mode that combines the "first mode" with the "second mode" or the "third mode". Furthermore, the drive unit 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, the imaging apparatus 101 according to an embodiment of the present invention, as shown in Figure 2, comprises a fixed-side member FB including a base member 18 as a fixed base, a movable-side member MB including a lens holder 2 capable of holding a lens body and movably provided with respect to the fixed-side member FB, a plurality of shape memory alloy wires SA, one end of which is fixed to the fixed-side member FB and the other end of which is fixed to the movable-side member MB, allowing the movable-side member MB to move, a drive device 10 (see Figure 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 Figure 9) capable of acquiring the resistance value of each of the plurality of shape memory alloy wires SA and controlling the drive device 10. The control device 20 is configured to control the drive device 10 so that a measuring 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, thereby acquiring the resistance value (measured resistance value) of the plurality of shape memory alloy wires SA.

[0158] The control device 20 is configured to set a target length (target resistance value) for each of the eight shape memory alloy wires SA corresponding to the desired orientation of the lens holder 2 (lens body). The control device 20 is configured to achieve the desired orientation of the lens holder 2 (lens body) by controlling the drive 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. In addition, the control device 20 can reduce the measured resistance value of a particular shape memory alloy wire SA by increasing the amount of power supplied to that particular wire SA, thereby causing that particular wire SA to contract.

[0159] This configuration has the effect of allowing for a more accurate estimation of the length of the shape memory alloy wire SA. This is because, in this configuration, the duration for which the measuring current is supplied is set independently of the duration for which the driving current is supplied. In other words, in this configuration, the duration for which the measuring current is supplied is set to a sufficiently long length.

[0160] Furthermore, this configuration has the effect of allowing the operation speed of an AD converter to be set lower when an AD converter is provided to detect the voltage across the shape memory alloy wire SA in order to derive the resistance value of the shape memory alloy wire SA, that is, allowing the use of a relatively inexpensive AD converter. This is because, in this configuration, the measurement current is supplied to the shape memory alloy wire SA at a timing different from that of the driving current, meaning that the duration for which the measurement current is supplied can be set relatively freely.

[0161] Furthermore, the control device 20 may control the drive device 10 to supply a drive current to each of the multiple shape memory alloy wires SA at different timings.

[0162] This configuration allows for more precise control over the expansion and contraction of each of the multiple shape memory alloy wires SA. This is because it prevents a portion of the driving current intended for a specific shape memory alloy wire SA from being supplied to another shape memory alloy wire SA.

[0163] The control device 20 may also control the drive device 10 to supply measuring current to each of the multiple shape memory alloy wires SA at different timings.

[0164] This configuration has the effect of allowing for more accurate acquisition of the resistance values ​​of each of the multiple shape memory alloy wires SA. This is because it prevents a portion of the measurement current that should be supplied to a specific shape memory alloy wire SA from being supplied to another shape memory alloy wire SA.

[0165] Furthermore, the control device 20 may control the drive device 10 such that the minimum time for which a driving current is continuously supplied to each of the multiple shape memory alloy wires SA is shorter than the time for which a measuring current is continuously supplied to each of the multiple shape memory alloy wires SA. In other words, the control device 20 may control the drive device 10 such that the time for which a measuring current is continuously supplied to each of the multiple shape memory alloy wires SA is longer than the time for which a driving current is continuously supplied to each of the multiple shape memory alloy wires SA.

[0166] This configuration offers the advantage of allowing for more flexible adjustment of the duration for which the drive current is supplied. This is because the duration for which the drive current is supplied can be made shorter than the duration for which the measurement current is supplied. Shortening the duration for which the drive current is supplied means that the amount of power supplied to a specific shape memory alloy wire SA in a single drive cycle (drive time slot) can be reduced, which in turn means that the shape memory alloy wire SA can be slightly heated and slightly contracted.

[0167] Furthermore, 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 drive 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] Furthermore, the control device 20 may control the drive device 10 to supply a drive current to each of the multiple shape memory alloy wires SA once in a single drive cycle, and to supply a measurement current to any one of the multiple shape memory alloy wires SA. The control device 20 may also control the drive device 10 to supply a measurement current to each of the multiple shape memory alloy wires SA by repeating the drive cycle multiple times.

[0170] This configuration has the effect of allowing the lens holder 2 (lens body) to be driven more smoothly. This is because the driving current can be supplied to each of the multiple shape memory alloy wires SA at relatively short intervals. It also prevents the period during which the driving current cannot be supplied to one of the multiple shape memory alloy wires SA from becoming excessively long.

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

[0172] This configuration has the effect of suppressing a decrease in control response speed and enabling smoother driving of the lens holder 2 (lens body). This is because measurement current can be supplied to each of the multiple shape memory alloy wires SA at relatively short intervals. It also prevents the period during which measurement current cannot be supplied to one of the multiple shape memory alloy wires SA from becoming excessively long.

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

[0174] This configuration has the effect of shortening the time required for one drive cycle. In other words, this configuration has the effect of suppressing the decrease in control response speed. Furthermore, compared to a configuration with a single drive device that supplies a drive current to each of the eight shape memory alloy wires (first wire SA1 to eighth wire SA8) and drives each of the eight shape memory alloy wires (first wire SA1 to eighth wire SA8), this configuration has the effect of extending the duration of the measurement time slot without increasing the time required for one drive cycle. Therefore, with this configuration, it is not necessary to increase the applied voltage when supplying the drive current to the shape memory alloy wire SA in order to extend the duration of the measurement time slot. As a result, this configuration can suppress the impact on the image due to noise caused by increasing the applied voltage.

[0175] Furthermore, as shown in Figure 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 that is movable relative to the fixed side member FB and includes a lens holder 2 that can hold a lens body so as to face the image sensor, a first wire SA1 as a first shape memory alloy wire with 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 with one end fixed to the fixed side member FB and the other end fixed to the movable side member MB, and the first wire provided on the base member 18 The device includes a first conductive path CD1 (see Figure 9) connected to one end of wire SA1, a second conductive path CD2 (see Figure 9) provided on the base member 18 and connected to one end of the second wire SA2, a common conductive path CD0 (see Figure 9) connected to the other ends of the first wire SA1 and the second wire SA2, and a drive device 10 (see Figure 9) configured to be electrically connected to the first conductive path CD1, the second conductive path CD2, and the common conductive path CD0, and capable of supplying current to the first wire SA1 and the second wire SA2 to drive them. As shown in Figure 12A, 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) are installed parallel to each other on the base member 18. Furthermore, the first point PT1 on the first conductive path CD1 (first conductive member CM1) is located next to 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 located next to the second point PT12 on the second conductive path CD2 (second conductive member CM2).Then, as shown in Figure 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, supplying current to the first wire SA1 and the second wire SA2, so that current flows from the first point PT1 to the second point PT2 of the first conductive path CD1 (first conductive member CM1), as indicated by arrow AR61 in Figure 12A, and also flows from the second point PT12 to the first point PT11 of the second conductive path CD2 (second conductive member CM2), as indicated by arrow AR62 in Figure 12A. The imaging device 101 is configured to switch between a first mode, a second mode in which the first conductive path CD1, the first wire SA1, and the common conductive path CD0 are electrically connected in series, as shown in Figure 10B, to supply current to the first wire SA1 and allow current to flow through the first conductive path CD1 (first conductive member CM1), and a third mode in which 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 and allow current to flow through the second conductive path CD2 (second conductive member CM2), as shown in Figure 10C. The imaging device 101 is configured to execute a combination of the first mode and the second or third mode.

[0176] This configuration has the effect of reducing the magnitude of the magnetic field formed around the conductive path that supplies current to the shape memory alloy wire SA. Therefore, this configuration has the effect of reducing noise on the image sensor 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 installed parallel to each other as shown in Figure 12A, and 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] Furthermore, since the drive unit 10 is configured to execute a composite mode that combines the first mode with the second mode or the third mode, it can accurately supply the desired amount of power to each of the first wire SA1 and the second wire SA2. The combination of the first mode with the second mode or the third mode is a combination of the first mode with the second mode, a combination of the first mode with the third mode, or a combination of the first mode with the second mode and the third mode. In addition, in a composite mode that combines the first mode with the second mode or the third mode, any of the operating modes may be executed first, each operating mode may be executed sequentially, and a measurement time slot or PWM OFF period may be inserted between each operating mode. Furthermore, the composite mode that combines the first mode with the second mode or the third mode may be executed during one or more drive cycles, or during one or more measurement cycles.

[0179] Furthermore, the drive unit 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 the second mode and the third mode, respectively.

[0180] This configuration has the effect of further reducing the magnetic field (induced magnetic field) that can adversely affect the image quality of the image sensor. In the first mode, 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 power to the first wire SA1, the larger the current flowing in the first mode, the smaller the current flowing in the second mode, which is executed after the first mode. The smaller 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 power to the second wire SA2, the larger the current flowing in the first mode, the smaller the current flowing in the third mode, which is executed after the first mode. The smaller 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] Furthermore, 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 the magnetic field (induced magnetic field) that could adversely affect the image quality of the image sensor. 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 magnetic field formed around the portion of the second conductive member CM2 embedded in the base member 18, to the image sensor is suppressed at least partially by the base member 18.

[0183] Furthermore, 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), as shown in Figure 4B. Alternatively, the first wire SA1 and the second wire SA2 may be arranged to intersect each other in a side view along a direction (Y axis direction) that is perpendicular to the respective extending direction (X axis direction) of the first wire SA1 and the second wire SA2, and perpendicular to the optical axis direction (Z axis direction), as shown in Figure 4A.

[0184] This configuration has the effect of further reducing the net magnetic field (induced magnetic field) that can adversely affect the image quality of the image sensor. In the first mode, when current is supplied simultaneously to both the first wire SA1 and the second wire SA2 (as shown in Figure 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] Furthermore, as shown in Figure 5, the base member 18 may have the shape of a rectangular frame 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 Figure 12A, the first conductive path CD1 (see Figure 9) may include a first terminal portion TM1, and the second conductive path CD2 (see Figure 9) may include a second terminal portion TM2. Also, the first terminal portion TM1 and the second terminal portion TM2 may be arranged 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 parallel to the second side 18E2, which is another one of the first side 18E1, second side 18E2, third side 18E3, and fourth side 18E4.

[0186] This configuration has the effect of making it easier to mount the image sensor. This is because a flexible printed circuit board or the like connected to the image sensor can be placed below the second side portion 18E2 of the base member 18.

[0187] Furthermore, the control method for the imaging device 101 according to the embodiment of the present invention includes the step of the control device 20 controlling the drive device 10 so that a measurement current is supplied to each of the multiple shape memory alloy wires SA at a timing different from the timing at which the drive current is supplied, and the control device 20 acquiring the resistance values ​​of the multiple shape memory alloy wires SA.

[0188] This control method allows the imaging device 101 to more accurately estimate the length of the shape memory alloy wire SA. This is because, in this control method, the duration for which the measurement current is supplied is set independently of the duration for which the driving current is supplied. In other words, in this control method, the duration for which the measurement current is supplied is set to a sufficiently long length.

[0189] Furthermore, as shown in Figure 10A, the control method for the imaging device 101 according to the embodiment of the present invention involves 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 Figure 12A, the first motor is used to cause current to flow from the first point PT1 to the second point PT2 of the first conductive path CD1 (first conductive member CM1) and from the second point PT12 to the first point PT11 of the second conductive path CD2 (second conductive member CM2). The process involves causing the drive unit 10 to execute a composite mode that combines the following: a second mode in which the first conductive path CD1, the first wire SA1, and the common conductive path CD0 are electrically connected in series, as shown in Figure 10B, to supply current to the first wire SA1 and allow current to flow through the first conductive path CD1; or a third mode in which the second conductive path CD2, the second wire SA2, and the common conductive path CD0 are electrically connected in series, as shown in Figure 10C, to supply current to the second wire SA2 and allow current to flow through the second conductive path CD2.

[0190] This control method allows the imaging device 101 to reduce the magnitude of the magnetic field formed around the conductive path for supplying current to the shape memory alloy wire SA. As a result, the imaging device 101 can reduce noise on the image sensor caused by the magnetic field formed around the conductive path.

[0191] Preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the embodiments described above. Various modifications and substitutions can be applied to the embodiments described above without departing from the scope of the present invention. Furthermore, each of the features described with reference to the embodiments described above may be combined as appropriate, as long as they do not conflict technically. [Explanation of symbols]

[0192] 2··Lens holder 2D··Movable side base 2D1··First movable side base 2D2··Second movable side base 2P··Cylindrical part 2S··Protruding part 2S1··First protruding part 2S2··Second protruding part 2T··Protruding part 2V··Projection part 4···Cover member 4A··Outer peripheral wall part 4A1··First side plate part 4A2··Second side plate part 4A3··Third side plate part 4A4··Fourth side plate part 4B··Top plate part 4K··Opening 4S··Storage part 5···Metal member 5F··Fixed side metal member 5F1··First fixed side terminal plate 5F2··Second fixed side terminal plate 5F3...3rd fixed terminal plate 5F4...4th fixed terminal plate 5F5...5th fixed terminal plate 5F6...6th fixed terminal plate 5F7...7th fixed terminal plate 5F8...8th fixed terminal plate 5M...Movable metal component 5M1...1st movable terminal plate 5M2...2nd movable terminal plate 5M3...3rd movable terminal plate 5M4...4th movable terminal plate 6...Leaf spring 6A...1st leaf spring 6A1...1st part 6A2...2nd part 6A3...3rd part 6A4...4th part 6A5...5th part 6AH1...1st through hole 6AH2...2nd through hole 6AH3...3rd through hole 6AH4...4th through hole 6AH5...5th through hole 6AH6...6th through hole 6B...2nd leaf spring 6B1...1st part 6B2...2nd part 6B3...3rd part 6B4...4th part 6B5...5th part 6BH1...1st through hole 6BH2...2nd through hole 6BH3...3rd through hole 6BH4...4th through hole 6BH5...5th through hole 6BH6...6th through hole 10...Drive unit 10A...1st drive unit 10A 10B...2nd drive unit 11...High potential source 12...Low potential source 13...Constant current source 18...Base member 18D...Fixed base section 18D1...First fixed base section 18D2...Second fixed base section 18E...Edge section 18E1...First edge section 18E2...Second edge section 18E3...Third edge section 18E4...Fourth edge section 18K...Opening 18T...Protruding section 18V...Projection101...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...Fourth 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 material CM1...First conductive material CM2...Second conductive material CM3...Third conductive material CM4...Fourth conductive material CM5...Fifth conductive member CM6...Sixth conductive member CP5...Fifth bonding surface CP6...Sixth bonding 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 section TM2...Second terminal section TM3...Third terminal section TM4...Fourth terminal section TM5...Fifth terminal section TM6...Sixth terminal section

Claims

1. A fixed side member including a fixed base, A lens holder capable of holding a lens body, and a movable side member provided movably with respect to the fixed side member, A plurality of shape memory alloy wires, one end of which is fixed to the fixed side member and the other end of which is fixed to the movable side member, allowing the movable side member to move; A drive device capable of driving each of the multiple shape memory alloy wires by supplying a driving current to each of the multiple shape memory alloy wires, The system includes a control device capable of acquiring the resistance values ​​of each of the multiple shape memory alloy wires and controlling the drive device, The plurality of shape memory alloy wires include a first wire and a second wire, The first wire is connected to the first conductive member installed on the fixed side member. The second wire is connected to the second conductive member installed on the fixed side member. The first conductive member and the second conductive member are installed parallel to each other. The control device is The drive current can be supplied simultaneously to the first wire and the second wire such that the direction of the drive current flowing through the first conductive member and the direction of the drive current flowing through the second conductive member are opposite to each other. The drive device is controlled so that a measuring current is supplied to each of the multiple shape memory alloy wires at a timing different from the timing at which the driving current is supplied, thereby obtaining the resistance values ​​of the multiple shape memory alloy wires. An imaging device characterized by the following features.

2. The time for continuously supplying the measuring current to each of the multiple shape memory alloy wires is longer than the minimum time for continuously supplying the driving current to each of the multiple shape memory alloy wires. The imaging apparatus according to claim 1.

3. The control device supplies the drive current to each of the plurality of shape memory alloy wires at different timings. The imaging apparatus according to claim 1 or 2.

4. The control device supplies the measuring current to each of the plurality of shape memory alloy wires at different timings. The imaging apparatus according to any one of claims 1 to 3.

5. The magnitude of the measurement current is smaller than the magnitude of the drive current. The imaging apparatus according to any one of claims 1 to 4.

6. The control device is In one drive cycle, the drive current is supplied once to each of the multiple shape memory alloy wires, and the measurement current is supplied to any one of the multiple shape memory alloy wires. The measurement current is supplied to each of the multiple shape memory alloy wires by repeating the aforementioned drive cycle multiple times. The imaging apparatus according to any one of claims 1 to 5.

7. The drive device includes a first drive device capable of driving each of the four shape memory alloy wires by supplying the driving current to each of the four shape memory alloy wires, and a second drive device capable of driving each of the other four shape memory alloy wires by supplying the driving current to each of the other four shape memory alloy wires. The imaging apparatus according to any one of claims 1 to 6.

8. The aforementioned lens body, An imaging device according to any one of claims 1 to 7, A camera module, including the camera module.

9. A control method for an imaging apparatus comprising: a fixed side member including a fixed base; a movable side member including a lens holder capable of holding a lens body and movably provided with respect to the fixed side member; a plurality of shape memory alloy wires, one end of which is fixed to the fixed side member and the other end of which is fixed to the movable side member, allowing the movable side member to move; a drive device capable of driving each of the plurality of shape memory alloy wires by supplying a drive current to each of the plurality of shape memory alloy wires; and a control device capable of controlling the drive device by acquiring the resistance value of each of the plurality of shape memory alloy wires, wherein The plurality of shape memory alloy wires include a first wire and a second wire, The first wire is connected to the first conductive member installed on the fixed side member. The second wire is connected to the second conductive member installed on the fixed side member. The first conductive member and the second conductive member are installed parallel to each other. The control device simultaneously supplies the driving current to the first wire and the second wire, respectively, such that the direction of the driving current flowing through the first conductive member and the direction of the driving current flowing through the second conductive member are opposite to each other. The control device includes the step of controlling the drive device so that a measuring current is supplied to each of the multiple shape memory alloy wires at a timing different from the timing at which the driving current is supplied, thereby obtaining the resistance values ​​of the multiple shape memory alloy wires. A control method for an imaging device, characterized by the following:

Images