JP2012137668A - Drive module, electronics and control method of drive module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize a movement start reference point of a driven body.SOLUTION: A drive module comprises: a support; a driven body; a spring member; drive means including a shape-memory alloy wire; and control means for controlling driving of the drive means. The control means includes: electrification means for electrifying the shape-memory alloy wire; resistance detection means for detecting an electric resistance value of the shape memory alloy wire; and command value generation means for generating a command value by subtracting a variation range of the electric resistance value according to a travel distance of the driven body from a reference value. The resistance detection means detects the electric resistance value of the shape-memory alloy wire, and the electrification means concurrently electrifies the shape-memory alloy wire while gradually increasing input electricity. And, before the driven body starts moving, when a local minimum point B appears in a function showing the electric resistance value with setting an input electricity level as an argument, the command value generation means generates the command value with setting the electric resistance value Rat a local maximum point C appearing after the local minimum point B as a reference value.

Description

  The present invention provides a drive module suitable for, for example, driving an optical system to adjust a focal position, or driving a movable member to be used as an actuator, an electronic device including the drive module, and control of the drive module It is about the method.

  Conventionally, various small electronic devices equipped with a drive module using a shape memory alloy wire have been proposed. The shape memory alloy wire described above is a member having a property of being restored to its original shape by heating to a certain temperature or higher even when deformed by applying an external force.

  Conventionally, as this type of drive module, for example, as shown in Patent Document 1 below, a support, a driven body provided to be reciprocally movable along a fixed direction with respect to the support, A configuration is known that includes a spring member that elastically holds a driving body and driving means having a shape memory alloy wire that is locked to the driven body. Both end portions of the shape memory alloy wire described above are held by wire holding portions fixed to the support, and an intermediate portion of the shape memory alloy wire is hung from below on a guide protrusion formed on the driven body. The shape memory alloy wire is attached in a state bent in a substantially V shape. According to this drive module, when the shape memory alloy wire is energized, the shape memory alloy wire is heated and contracted by the Joule heat generated by the energization, and the driven body has a restoring force (bias force) of the spring member. The driven body is moved downward by the restoring force of the spring member by moving upward against the force and stopping energization to the shape memory alloy wire.

  In addition, the drive module described above is provided with a control unit that controls the drive of the drive unit by setting a command value of the electrical resistance of the shape memory alloy wire and controlling energization of the shape memory alloy wire. . This control means first detects the resistance peak value (the maximum value of the electrical resistance value) of the shape memory alloy wire, uses the resistance peak value as a reference value, and responds to the desired amount of movement of the driven body from the reference value. The command value is generated by subtracting the change width of the electrical resistance value. And a control means adjusts the energization amount with respect to a shape memory alloy wire so that the said command value and the detected value of the electrical resistance of a shape memory alloy wire may correspond. Thereby, the driven body can be moved by a desired amount of movement.

JP 2009-127578 A

  By the way, in the drive module having the above-described configuration, when the shape memory alloy wire is attached, the driven body floats if the shape memory alloy wire is stretched too much, so that the shape memory alloy wire has a slight slack, Both ends of the shape memory alloy wire are fixed to the wire holding portion, and an intermediate portion of the shape memory alloy wire is hung on the guide protrusion of the driven body. For this reason, in the drive module described above, when the input power is gradually increased from the non-energized state to the shape memory alloy wire, the shape memory alloy wire is first heated and the shape memory alloy wire is heated as shown in FIG. The electric resistance value increases monotonously. Then, when the shape memory alloy wire reaches the peak value (transformation start point) and the shape memory alloy wire starts to contract, the shape memory alloy wire switches from monotonically increasing to monotonically decreasing. Then, the slack of the shape memory alloy wire gradually decreases due to the contraction of the shape memory alloy wire. When the slack of the shape memory alloy wire disappears, the contraction of the shape memory alloy wire stops, and the electric resistance value of the shape memory alloy wire becomes smaller. Switch from monotonic decrease to monotonic increase. Thereafter, when the shape memory alloy wire contracts again and the guide protrusion is pressed upward and the driven body moves upward against the restoring force (bias force) of the spring member, the electrical resistance value of the shape memory alloy wire becomes Switch from monotonic increase to monotonic decrease. Thereafter, when the shape memory alloy wire contracts to the limit (end of transformation), the electrical resistance value of the shape memory alloy wire switches from monotonically decreasing to monotonically increasing.

  That is, in the drive module having the above-described configuration, if the shape memory alloy wire is slack, the driven body does not move even if the shape memory alloy wire contracts due to the electrical resistance value of the shape memory alloy wire reaching the resistance peak value. . Moreover, it is difficult to make the amount of slackness of the shape memory alloy wire constant when attaching the shape memory alloy wire, and there are individual differences in the amount of slackness of the shape memory alloy wire. For this reason, in the conventional drive module that generates the command value using the resistance peak value of the shape memory alloy wire as the reference value, the movement start reference point of the driven body varies and individual differences occur in the drive accuracy of the drive module. There is a problem.

  The present invention has been made in consideration of the above-described conventional problems, and provides a drive module, an electronic apparatus, and a drive module control method in which the movement start reference point of the driven body is stable and individual differences in drive accuracy are unlikely to occur. The purpose is to do.

  The drive module according to the present invention includes a support, a driven body that is reciprocally movable along a fixed direction with respect to the support, a spring member that elastically holds the driven body, and the driven A drive means for moving the driven body against the restoring force of the spring member by deforming the shape memory alloy wire by heat generated by energization; A control module configured to control the drive of the drive means by setting a command value of the electrical resistance of the shape memory alloy wire and controlling energization of the shape memory alloy wire, the control means In addition, an energizing means for energizing the shape memory alloy wire, a resistance detecting means for detecting an electric resistance value of the shape memory alloy wire, and a variation range of the electric resistance value according to the amount of movement of the driven body Based on Command value generating means for generating the command value by subtracting from the value, and gradually detecting the input power by the energizing means while detecting the electrical resistance value of the shape memory alloy wire by the resistance detecting means. When the shape memory alloy wire is energized while increasing, and when a minimum point appears in a function representing an electric resistance value with an input power value as an independent variable before the driven body starts moving, the minimum The command value generating means generates the command value using the electric resistance value at the maximum point appearing after the point as the reference value.

  The drive module control method according to the present invention includes a support, a driven body that is reciprocally movable along a predetermined direction with respect to the support, and a spring member that elastically holds the driven body. And a shape memory alloy wire locked to the driven body, and the shape memory alloy wire is deformed by heat generated by energization to move the driven body against the restoring force of the spring member. Control of a drive module comprising: drive means; and control means for controlling drive of the drive means by setting a command value of electrical resistance of the shape memory alloy wire and controlling energization to the shape memory alloy wire A resistance detecting step of energizing the shape memory alloy wire while gradually increasing an input power while detecting an electrical resistance value of the shape memory alloy wire; and the resistance detecting step. When a minimum point appears in a function representing an electrical resistance value with the input power value as an independent variable before the driven body starts moving in step S2, the electrical resistance value at the maximum point appearing after the minimum point is used as a reference value. And a command value generating step of generating the command value by subtracting a change width of the electric resistance value corresponding to the movement amount of the driven body from the reference value.

  In the drive module described above, when the shape memory alloy wire is attached in a slack state, when the input power is gradually increased from the non-energized state and the shape memory alloy wire is energized, the electrical resistance value of the shape memory alloy wire As shown in FIG. 9, as the input power increases, first, it monotonously increases, and when the transformation (shrinkage) of the shape memory alloy wire starts, it switches from monotonic increase to monotonic decrease (transformation start point). After that, when the shape memory alloy wire ceases to loosen, it switches from monotonic decrease to monotonic increase (minimum point), and then when the driven body starts moving against the restoring force of the spring member, the monotonic increase decreases monotonically. Switch to (maximum point). Then, when the shape memory alloy wire reaches the transformation end point, the monotonous decrease is switched to the monotonous increase. The above-mentioned “transformation start point” is a point at which the shape memory alloy wire starts to contract, and variation occurs when the amount of slack of the shape memory alloy wire is different, but the above-mentioned “maximum point” moves the driven body. This is the movement start point to be started, and is constant even when the slack amount of the shape memory alloy wire is different. Therefore, by generating a command value using the electric resistance value at the maximum point as a reference value, the movement start reference point of the driven body is constant even when the amount of looseness of the shape memory alloy wire varies, and the driving accuracy Individual differences are less likely to occur.

For example, when the drive module described above is placed under a high environmental temperature, the shape memory alloy wire may contract, and the shape memory alloy wire may not be slack. Thus, when there is no slack in the shape memory alloy wire, the minimum point does not appear before the driven body starts moving.
Therefore, in the drive module according to the present invention, when the minimum point does not appear before the driven body starts to move, the command value generating means uses the maximum value of the electric resistance value as the reference value and the command value Is preferably generated.
In the drive module control method according to the present invention, when the minimum point does not appear before the driven body starts moving during the command value generation step, the maximum value of the electrical resistance value is set. The command value is preferably generated as a reference value.

  As a result, when the shape memory alloy wire is energized while gradually increasing the input power from the non-energized state in a state where the shape memory alloy wire is not slack, the electrical resistance value of the shape memory alloy wire is as shown in FIG. In addition, the input power increases monotonously as the input power increases, and then switches from monotonic increase to monotonic decrease. When the shape memory alloy wire reaches the transformation end point, it switches from monotonic decrease to monotonic increase. The point of time when the monotonic increase is changed to the monotonic decrease is a movement start point at which the driven body starts moving, and the electric resistance value becomes the maximum value. The movement start point at which the electrical resistance value reaches the maximum value coincides with the “maximum point” described above. Therefore, even when the shape memory alloy wire is attached without being slackened, it becomes the same movement start reference point as when the shape memory alloy wire is slackened.

In addition, an electronic apparatus according to the present invention includes the drive module described above.
Due to such a feature, the drive accuracy of the drive module is stabilized, so that individual differences are unlikely to occur in the quality of the electronic device.

  According to the drive module, the electronic device, and the drive module control method according to the present invention, it is possible to stabilize the drive movement reference point of the driven body, and to suppress individual differences in drive accuracy.

It is a perspective view of the drive module in the embodiment of the present invention. It is a disassembled perspective view which shows the structure of the drive module in embodiment of this invention. It is a disassembled perspective view which shows the structure of the drive unit in embodiment of this invention. It is a perspective view which shows the drive unit in embodiment of this invention. It is sectional drawing which follows the AA line of FIG. It is a functional block diagram of the drive module in the embodiment of the present invention. It is a graph which shows the drive mode of the drive module in embodiment of this invention. It is a flowchart figure which shows the control method of the drive module in embodiment of this invention. It is a graph which shows the function showing the electrical resistance value which makes the input power value of the drive module in the embodiment of the present invention an independent variable. It is a graph which shows the drive mode of the drive module in the modification of embodiment of this invention. It is a graph which shows the drive mode of the drive module in the modification of embodiment of this invention. It is drawing of the electronic device in embodiment of this invention, (a) Front surface perspective view, (b) Back surface perspective view, (c) It is sectional drawing which follows the FF line | wire of (b).

Embodiments of a drive module, an electronic apparatus, and a drive module control method according to the present invention will be described below with reference to the drawings.
For ease of viewing in some drawings, for example, components such as the lens unit 12 shown in FIG. 5 are omitted as appropriate.
Further, a symbol M in the figure is a virtual axis line of the drive module 1 that coincides with the optical axis of the lens 50 shown in FIG. 5, and indicates a moving direction of the lens frame 4 described later. Hereinafter, in order to simplify the description, in the description of each disassembled component member, the position and direction may be referred to based on the positional relationship with the axis M at the time of assembly. For example, even when there is no clear circle or cylindrical surface in the component, the direction along the axis M is simply referred to as “axial direction” and the direction perpendicular to the axis M is simply “radial direction” unless there is a risk of misunderstanding. The direction around the axis M may be simply referred to as “circumferential direction”. Further, a control board 32 side to be described later in the axial direction is referred to as “downward”, and the opposite side is referred to as “upward”.

First, the structure of the drive module 1 in this embodiment is demonstrated.
As shown in FIGS. 1 and 2, the drive module 1 of the present embodiment is a drive module for reciprocating the lens 50 (lens unit 12) shown in FIG. 5 along the axial direction, and is mounted on an electronic device or the like. It is what is done. The drive module 1 is disposed so as to cover the drive unit 31, a control board 32 serving as control means, an adapter 30 positioned on the control board 32, a drive unit 31 disposed on the adapter 30. And a cover 11.

  As shown in FIG. 3, the drive unit 31 includes a lens frame 4 as a driven body, a module frame 5 as a support, an upper plate spring 6 and a lower plate spring 7, a module lower plate 8, a power supply member 9, and a shape. A memory alloy (Shape Memory Alloy, hereinafter abbreviated as SMA) wire 10 is a main constituent member, and these constituent members are assembled together to form one actuator.

  As shown in FIGS. 3 to 5, the lens frame 4 described above is inserted inside the module frame 5 so as to be movable in the axial direction, and an upper leaf spring 6 is arranged at the upper ends of the lens frame 4 and the module frame 5. The lower plate spring 7 is disposed at the lower ends of the lens frame 4 and the module frame 5, and the lens frame 4 and the module frame 5 are sandwiched between the upper plate spring 6 and the lower plate spring 7. Yes. The upper leaf spring 6 is fixed to the upper ends of the lens frame 4 and the module frame 5 by caulking. A module lower plate 8 is stacked below the lower plate spring 7, and a power supply member 9 is stacked below the module lower plate 8. The lower plate spring 7, the module lower plate 8, and the power supply are stacked. The members 9 are fixed to the lower end of the module frame 5 by caulking, and the lower leaf spring 7 is fixed to the lower end of the lens frame 4 by caulking. The cover 11 is placed and fixed on the upper surface of the module lower plate 8.

  The lens frame 4 described above is a substantially cylindrical tubular member extending along the axial direction with the axis M as the central axis, and as shown in FIG. A female screw is formed on the inner peripheral surface 4F of the portion 4A. The lens unit 12 is screwed onto the inner peripheral surface 4F of the housing portion 4A, whereby the lens unit 12 is held by the lens frame 4. The lens unit 12 includes a cylindrical tube portion 51 having a male screw formed on the outer peripheral surface, and a lens 50 fitted inside the tube portion 51.

  On the outer wall surface 4B of the lens frame 4, projecting portions 4C (convex portions) projecting radially outward at an interval of approximately 90 degrees in the circumferential direction are extended in the axial direction. An upper fixing pin 13A and a lower fixing pin 13B are erected on the upper end surface 4a and the lower end surface 4b of the portion 4C, respectively. The upper fixing pin 13 </ b> A holds the upper leaf spring 6, and the lower fixing pin 13 </ b> B holds the lower leaf spring 7.

Since the upper fixing pin 13A and the lower fixing pin 13B are arranged at a coaxial position parallel to the axis M, the insertion positions of the upper fixing pin 13A and the lower fixing pin 13B in the upper leaf spring 6 and the lower leaf spring 7 are inserted. Are standardized.
Note that the positions of the upper fixing pin 13A and the lower fixing pin 13B in plan view may be different. For example, the upper fixing pin 13A is attached to each upper end surface 4a of the two protruding portions 4C out of the four protruding portions 4C. Alternatively, the lower fixing pins 13B may be erected on the lower end surfaces 4b of the remaining two protruding portions 4C.

  The lens frame 4 is provided with a guide protrusion 4D on which the SMA wire 10 can be hung. The guide projection 4D is integrally joined to the outer peripheral surface of the lower end of one of the plurality of protrusions 4C, and a distal end key portion (locking portion) 4D1 is formed to be hooked and locked by the SMA wire 10. Has been. The distal end key portion 4D1 is for lifting the lens frame 4 upward and moving it upward along the axial direction by contraction of the SMA wire 10 hung thereon.

  Further, the lens frame 4 is provided with a spring holding portion 33 for holding the coil spring 34 shown in FIG. 2 that urges the lens frame 4 downward. The spring holding portion 33 is a columnar convex portion erected on the upper end surface of the guide protrusion 4D, and the coil spring 34 shown in FIG. Accordingly, it is possible to suppress the movement of the SMA wire 10 that is contracted due to the influence of the surrounding environment and the like to raise the lens frame 4. The lens frame 4 is integrally formed of a thermoplastic resin that can be heat-clamped or ultrasonically-clamped, such as polycarbonate (PC) or liquid crystal polymer (LCP) resin.

  The module frame 5 is a cylindrical member extending along the axial direction with the axis M as the central axis, and the outer shape in plan view is formed in a substantially rectangular shape as a whole, and penetrates in the central portion in the axial direction. An accommodating portion 5A having a circular shape in cross section is formed. The lens frame 4 described above is accommodated in the accommodating portion 5A. At the upper and lower four corners of the module frame 5, planar upper and lower end surfaces 5a and 5b formed along a virtual vertical plane with respect to the axis M are formed, respectively, and upper fixing pins 14A are formed upward on each upper end surface 5a. Each lower end pin 5B protrudes downward from each lower end surface 5b.

  The upper fixing pin 14A holds the upper leaf spring 6, and the lower fixing pin 14B holds the lower leaf spring 7, the module lower plate 8, and the power supply member 9. Note that the position of the upper fixing pin 14A in plan view may be different from the arrangement of the lower fixing pin 14B, but in this embodiment, they are arranged at coaxial positions parallel to the axis M, respectively. For this reason, the insertion positions of the upper fixing pin 14A and the lower fixing pin 14B in the upper leaf spring 6 and the lower leaf spring 7 are made common. Further, the distance between the upper and lower end surfaces 5 a and 5 b described above is set to be substantially the same distance as the distance between the upper and lower end surfaces 4 a and 4 b of the lens frame 4.

  A notch 5B having a size in which the groove width in a plan view is fitted to the guide projection 4D of the lens frame 4 so as to be movable in the axial direction is formed at a lower portion of one corner of the module frame 5. The notch 5B penetrates the guide projection 4D of the lens frame 4 in a state in which the lens frame 4 is inserted and accommodated in the module frame 5 from below, and the tip key portion 4D1 of the guide projection 4D is inserted into the diameter of the module frame 5. This is for projecting outward in the direction and positioning the lens frame 4 in the circumferential direction.

  As shown in FIGS. 3 and 4, the SMA wire 10 is held at the two corners adjacent to the notch 5B of the module frame 5 on the side surface in the same direction as the corner provided with the notch 5B. A pair of locking grooves 5C for attaching the wire holding members (holding terminals) 15A, 15B to be formed are formed.

  Pins 35A and 35B are formed at positions where the wire holding members 15A and 15B are arranged on the side surface of the module frame 5, respectively. Further, a groove portion 36 that is filled with an adhesive and fixes the module frame 5 and the wire holding members 15A and 15B is formed below the pins 35A and 35B. And when fixing wire holding member 15A, 15B to the module frame 5, the wall part 35C which can suppress that wire holding member 15A, 15B rotates is formed. The wall portion 35 </ b> C extends laterally (perpendicular to the side surface) from the side surface of the module frame 5.

  Further, in the present embodiment, the module frame 5 is integrally formed of a thermoplastic resin that can be heat-clamped or ultrasonically caulked, such as polycarbonate (PC), liquid crystal polymer (LCP) resin, and the like, in the same manner as the lens frame 4. ing.

  The wire holding member 15A is attached to the side surface on the side where the pair of terminal portions 9C of the power supply member 9 protrudes from the drive module 1, and the wire holding member 15B is connected to the pair of terminal portions 9C of the power supply member 9 from the drive module 1. It is attached to the side of the side that does not protrude.

  As shown in FIG. 4, the wire holding members 15 </ b> A and 15 </ b> B are conductive members such as a metal plate formed in a key shape formed by caulking the end portion of the SMA wire 10 to the wire holding portion 15 b. The wire holding members 15A and 15B are formed with through holes 36A and 36B that fit into the pins 35A and 35B of the module frame 5, respectively. Further, through holes 37A and 37B for pouring the adhesive are formed below the through holes 36A and 36B in the axial direction. Then, when the module frame 5 and the wire holding members 15A and 15B are fixed, the arm portions 38A and 38B for contacting the wall portion 35C of the module frame 5 and suppressing the rotation of the wire holding members 15A and 15B. Are formed respectively. The end portion of the SMA wire 10 is positioned and held by fitting the locking portion 5C and the pins 35A and 35B from the side and bringing the wall portion 35C and the arm portions 38A and 38B into contact with each other.

  The wire holding members 15 </ b> A and 15 </ b> B are provided with a piece-like terminal portion 15 a on the opposite side of the wire holding portion 15 b (clamping position) of the SMA wire 10, and the terminal portion 15 a is attached to the module frame 5 when attached to the module frame 5. It protrudes slightly below the module lower plate 8 stacked below.

  Further, the SMA wire 10 whose both ends are held by the pair of wire holding members 15A and 15B is locked from below to the front end key portion 4D1 of the guide projection 4D of the lens frame 4 protruding from the notch 5B of the module frame. Yes.

  As shown in FIGS. 3 and 4, an upper leaf spring 6 and a lower leaf spring 7 are laminated on the upper and lower portions of the module frame 5 and the lens frame 4 inserted into the module frame 5, respectively. The upper leaf spring 6 and the lower leaf spring 7 are flat plate spring members punched into substantially the same shape, and are made of a metal plate such as a stainless steel (SUS) steel plate.

  The shape of the upper leaf spring 6 (lower leaf spring 7) has a substantially rectangular shape in plan view, similar to the upper (lower) end of the module frame 5, and is coaxial with the axis M at the center. A circular opening 6C (7C) that is slightly larger than the inner peripheral surface 4F of the frame 4 is formed, and has a ring shape as a whole.

  In the vicinity of the corner of the upper leaf spring 6 (lower leaf spring 7), the upper fixing pins 14A (lower fixing pins 14B) formed in the vicinity of the corners of the module frame 5 correspond to the positions of the upper fixing pins 14A. Four through holes 6B (7B) that can be inserted through the pins 14A (lower fixing pins 14B) are formed. Thereby, positioning in the plane orthogonal to the axis line M with respect to the module frame 5 is possible.

  Further, the upper plate spring 6 (lower plate spring 7) has upper fixing pins 13A (lower fixing pins) corresponding to the positions of the upper fixing pins 13A (lower fixing pins 13B) formed on the lens frame 4. Four through holes 6A (7A) that can be respectively inserted into the pins 13B) are formed.

  Further, a ring portion 6F (7F) is formed on the outer side in the radial direction of the opening 6C (7C), and in the circumferential direction from a position in the vicinity of the through holes 6A (7A) that face each other diagonally across the axis M. Four slits 6D (7D) extending in a substantially semicircular arc shape are formed so as to overlap each other in the radial direction by a substantially quadrant arc.

  Thereby, four spring parts 6E (7E) extended from the rectangular frame outside the upper leaf | plate spring 6 (lower leaf | plate spring 7) to the substantially quadrant arc shape one each through-hole 6A ( 7A) A leaf spring member extending in the vicinity is formed.

  Thus, the outer shape of the upper leaf spring 6 (lower leaf spring 7) is provided in a rectangular shape substantially matching the outer shape of the module frame 5, and the spring portion 6E (7E) and the ring portion 6F (7F) are formed in the opening 6C ( 7C) is formed in a ring-shaped region. Then, depending on the arrangement of the upper fixing pin 14A (lower fixing pin 14B) for fixing the upper leaf spring 6 (lower leaf spring 7) to the module frame 5, a through-hole that is a fixed portion is provided at a corner having a sufficient space. Since the hole 6B (7B) is provided, the shape of the through-hole 6B (7B) can be separated from the spring portion 6E (7E), so that manufacturing by precise punching or etching is easy.

  The module lower plate 8 allows the lower fixing pins 14B of the module frame 5 to pass through the through holes 7B of the lower leaf spring 7, and the lower fixing pins 13B of the lens frame 4 accommodated in the module frame 5 are lower plates. The lower plate spring 7 is stacked between the module frame 5 with the lower plate spring 7 sandwiched from the lower side in a state of passing through the through hole 7A of the spring 7, and the rectangular outer frame of the lower plate spring 7 is attached to the end surface of the module frame 5. It fixes to a pressing state with respect to 5b.

  The shape of the module lower plate 8 is a plate-like member having a rectangular outer shape that is substantially the same as the outer shape of the module frame 5, and a substantially circular opening 8 </ b> A centering on the axis M penetrates in the center in the thickness direction. Is formed. Then, on the side of the upper surface 8a laminated on the lower leaf spring 7 at the time of assembly, a position 4 corresponding to the position of the lower fixing pin 13B of the lens frame 4 is used to avoid interference with a caulking portion described later. Two U-shaped concave portions 8B are formed. In addition, through holes 8C through which the lower fixing pins 14B are inserted are formed at the corners located on the periphery of the module lower plate 8 corresponding to the positions of the lower fixing pins 14B of the module frame 5. ing. The material of the module lower plate 8 is, for example, a synthetic resin having electrical insulation and light shielding properties. Further, since the module lower plate 8 has electrical insulation, it is an insulating member that fixes the power supply member 9 to the lower plate spring 7 in an electrically insulated state.

  The power supply member 9 includes a pair of electrodes 9a and 9b each formed of a plate-shaped metal plate. Each of the electrodes 9a and 9b includes a substantially L-shaped wiring portion 9B that follows the outer shape of the module lower plate 8, and a terminal portion 9C that protrudes outside the outer shape of the module lower plate 8 from the end of the wiring portion. It consists of a polygonal metal plate. Each of the wiring portions 9B has two lower fixing pins adjacent to each other along the outer shape of the module lower plate 8 out of the lower fixing pins 14B of the module frame 5 protruding downward from the lower surface of the module lower plate 8. Two through holes 9A for positioning the electrodes 9a and 9b with respect to the module frame 5 by inserting the pins 14B, respectively, are provided.

Further, as shown in FIG. 4, the terminal portions 9C of the pair of electrodes 9a and 9b are provided so as to protrude in parallel downward in the axial direction from the side surface of the module frame 5 on which the wire holding member 15A is attached. It has been.
Therefore, one electrode 9a is notched in a concave shape to electrically connect the terminal portion 15a of the wire holding member 15A to the side surface on the wiring portion 9B between the through hole 9A and the terminal portion 9C. A conductive connection portion 9D is provided.
On the other hand, the other electrode 9b is formed with a conductive connection portion 9D that is notched at a connection location with the terminal portion 15a of the wire holding member 15B on the side surface of the wiring portion 9B. In the conductive connection portion 9D, the other electrode 9b and the wire holding member 15B are electrically connected.
Moreover, as means for electrically connecting each conductive connection portion 9D to the terminal portion 15a, for example, soldering or adhesion using a conductive adhesive can be employed.

  As shown in FIG. 2, the cover 11 is a member in which a side wall portion 11 </ b> D that covers the module frame 5 is extended from the outer edge portion of the upper surface 11 </ b> E to the lower side, and a rectangular opening 11 </ b> C is formed on the lower side. A circular opening 11A centering on the axis M is provided at the center of the upper surface 11E. The size of the opening 11A is set so that the lens unit 12 can be taken in and out.

  As shown in FIGS. 1 and 2, the control board 32 is a control unit that controls the drive of the drive unit 31 by setting a command value for the electrical resistance of the SMA wire 10 and controlling the energization of the SMA wire 10. It is a substrate that supplies control signals and power to the drive unit 31. As a schematic configuration of the control board 32, a printed board having printed wirings 39 and 39 electrically connected to the terminal portions 9C of the pair of electrodes 9a and 9b formed on the surface, and mounted on the printed board. And a control circuit (not shown). More specifically, the control board 32 is a control means for energizing the pair of electrodes 9a and 9b via the printed wirings 39 and 39 to appropriately expand and contract the SMA wire 10, and by extending and contracting the SMA wire 10, the lens frame 4 is moved along the axial direction relative to the module frame 5 to place the lens frame 4 at a desired position (in-focus position).

As shown in FIG. 6, the control board 32 described above includes a resistance detection unit 320 that detects an electrical resistance value of the SMA wire 10, and a command value generation unit 321 that generates a command value R _t for controlling the SMA wire 10. , a conductive member 322 that performs energization against SMA wire 10 so that the detected value R detected by the resistance detection means 320 coincides with the command value R _t generated by the command value generation means 321, is provided .

  Next, the assembly method of the drive module 1 having the above-described configuration will be described in order.

  In the first step, first, the lens frame 4 is inserted into the housing portion 5A of the module frame 5 from below, and the upper end surface 5a of the module frame 5 and the upper end surface 4a of the lens frame 4 are aligned at the same height. Then, the upper fixing pins 14A of the module frame 5 and the upper fixing pins 13A of the lens frame 4 are inserted through the through holes 6B and 6A of the upper leaf spring 6, respectively.

  Thereafter, the tips of the upper fixing pins 13A and 14A protruding through the through holes 6A and 6B of the upper leaf spring 6 are heat-clamped by a heater chip (not shown), as shown in FIGS. In this way, a caulking portion 16 that is a first fixing portion and a caulking portion 17 that is a second fixing portion are formed.

At this time, the upper end surface 4a of the lens frame 4 and the upper end surface 5a of the module frame 5 are aligned on the same plane, and the plate-like upper leaf spring 6 is arranged without being deformed, and heat caulking is performed. It can be carried out. Therefore, it is not necessary to hold down the upper plate spring 6 that is deformed, so that the caulking work can be easily performed. Further, the occurrence of floating or the like due to the deformation of the upper leaf spring 6 can be prevented.
Moreover, since the height of each heater chip can be made common, even if both the crimping portions 16 and 17 are formed at the same time, variations in the crimping accuracy can be reduced.

  Next, in the second step, the lower fixing pins 13B of the lens frame 4 are inserted into the through holes 7A of the lower leaf spring 7, respectively. At that time, the lower fixing pins 14B of the module frame 5 are simultaneously inserted into the through holes 7B of the lower plate spring 7, the through holes 8C of the module lower plate 8, and the through holes 9A of the power supply member 9. Thereafter, the front end portion of each lower fixing pin 13B penetrating through each through-hole 7A of the lower leaf spring 7 is heat-clamped with a heater chip (not shown), and the first end as shown in FIG. A caulking portion 18 that is a fixing portion is formed.

At this time, since the axial distance between the upper and lower end surfaces 4a and 4b of the lens frame 4 is equal to the axial distance between the upper and lower end surfaces 5a and 5b of the module frame 5, the lower end surfaces 4b and 5b are on the same plane. Since the module lower plate 8 can be stacked and heat-clamped without deforming the flat plate-like lower leaf spring 7, the occurrence of floating due to the deformation of the lower leaf spring 7 can be prevented. can do.
Moreover, since the height of each heater chip can be made common, even if the caulking portion 18 is formed at the same time, variations in caulking accuracy can be reduced.

  Next, in the third step, the lower end portion of each lower fixing pin 14B penetrating through the through-holes 7B, 8C, 9A is heat-clamped with a heater chip (not shown) and shown in FIG. Thus, the caulking portion 19 that is the second fixing portion is formed.

At this time, since the height of each heater chip can be made common, even if the caulking portion 19 is formed at the same time, variations in caulking accuracy can be reduced.
Further, since the recess 8 </ b> B is formed in the module lower plate 8, the caulking portion 18 formed in the second step does not contact the module lower plate 8.

  By performing the operations in the first to third steps, the upper plate spring 6, the lower plate spring 7, the module lower plate 8, and the power supply member 9 are laminated and fixed to both ends of the lens frame 4 and the module frame 5.

  Since the upper fixing pin 13A and the lower fixing pin 13B, and the upper fixing pin 14A and the lower fixing pin 14B are provided coaxially, the caulking portion 16 is used in caulking in the first to third steps. , 18 and the caulking portions 17, 19 have the same position on the plane of the heater chip. Therefore, since it is not necessary to change the heater chip position in each caulking, the caulking work can be performed efficiently.

  Next, in a fourth step (arrangement step), the pair of wire holding members 15 </ b> A and 15 </ b> B to which the SMA wire 10 is attached are fixed to the module frame 5. Specifically, the through holes 36A and 36B of the wire holding members 15A and 15B are fitted to the two pins 35A and 35B formed on the module frame 5, and the wire holding members 15A and 15B are fitted to the locking grooves 5C. Lock each one. At that time, the central portion of the SMA wire 10 is locked to the tip key portion 4D1 of the guide projection 4D from below. The terminal portions 15a of the wire holding members 15A and 15B protrude below the module lower plate 8, and are respectively connected to the conductive connection portions 9D of the electrodes 9a and 9b, which are power supply members 9 fixed to the module lower plate 8. Locked or placed close together. When the pair of wire holding members 15A and 15B are assembled to the module frame 5, the length of the SMA wire 10 is adjusted so that the SMA wire 10 is locked to the distal end key portion 4D1 in a slightly slack state. deep.

  Next, in the fifth step (fixing step), a thermosetting adhesive is poured into the through holes 37 </ b> A and 37 </ b> B and filled in the groove portion 36 of the module frame 5. When the groove portion 36 is filled with the thermosetting adhesive, it is placed in a heating furnace in order to cure the adhesive. In the heating furnace, for example, by heating at about 100 ° C. for about 20 to 30 minutes, the adhesive is cured and the module frame 5 and the wire holding members 15A and 15B are bonded and fixed.

  After the module frame 5 and the wire holding members 15A and 15B are bonded and fixed, each terminal portion 15a is electrically connected to the conductive connection portion 9D using, for example, soldering or a conductive adhesive. .

Next, in the sixth step, the cover 11 is covered from above the module frame 5, and the side wall portion 11 </ b> D and the module lower plate 8 are joined. For example, an engaging claw or the like is provided on the side wall part 11D and joined by fitting, or the side wall part 11D and the module lower plate 8 are bonded or welded to join. Further, the caulking portions 16 and 17 are in a state of being separated from the back surface of the upper surface 11E of the cover 11, respectively.
This completes the assembly of the drive module 1 main body.

  Thereafter, the adapter 30 is attached below the drive unit 31 and then attached onto the substrate. For mounting the drive module 1 on the substrate, fixing means such as adhesion and fitting can be employed. Note that the substrate may be an independent member attached to the drive module 1 or a member connected to and disposed on an electronic device or the like.

  Further, the lens unit 12 is screwed into the lens frame 4 through the opening 11 </ b> A of the cover 11. As described above, the lens unit 12 is attached last because the lens of the lens unit 12 is not soiled or dust is attached by the assembling work. For example, the drive module 1 is attached to the lens unit 12. This process is performed at an early stage (sixth stage) when the product is shipped in a product state where the lens is attached, or when the opening 11A of the cover 11 is desired to be smaller than the outer shape of the lens unit 12, for example, when the aperture stop is also used. It may be carried out before the process).

  Next, the operation of the drive module 1 will be described.

  The drive module 1 acts on the lens frame 4 such as the urging force of the coil spring 34 and the restoring force from the upper leaf spring 6 and the lower leaf spring 7 by the crimping portions 16 and 18 in a state where power is not supplied to the terminal portion 9C. Accordingly, the lens frame 4 to which the lens unit 12 is attached is held at a fixed position in the axial direction.

  When driving the drive module 1 described above, power is supplied from the control board 32 to the power supply member 9 via the terminal portion 9C according to a control method described later. At this time, since the electrode 9a, the wire holding member 15A, the SMA wire 10, the wire holding member 15B, and the electrode 9b are respectively conducted, current flows through the SMA wire 10.

  Therefore, when the SMA wire 10 is energized, Joule heat is generated in the SMA wire 10, and when the temperature of the SMA wire 10 rises and exceeds a predetermined temperature, the SMA wire 10 contracts to a length corresponding to the temperature. To do. As a result, the guide protrusion 4D of the lens frame 4 is pushed up by the SMA wire 10, the coil spring 34, the upper leaf spring 6 and the lower leaf spring 7 are deformed, respectively, and an elastic restoring force corresponding to the amount of deformation acts on the lens frame 4. To do. Then, the lens frame 4 stops at a position where this elastic restoring force is balanced with the tension of the SMA wire 10. At this time, since the upper leaf spring 6 and the lower leaf spring 7 constitute a parallel spring, the lens frame 4 accurately moves along the axis M without being along an axial guide member or the like. Is done. For this reason, it is possible to reduce the number of parts and reduce the size. Further, since no sliding load is generated on the guide member, low power consumption can be realized.

On the other hand, when the supply of power is stopped and the energization to the SMA wire 10 is stopped, the SMA wire 10 can be extended, the lens frame 4 is pushed down by the elastic restoring force, and the lens frame 4 moves to a lower balance position. .
In this way, the lens frame 4 is moved in the direction of the axis M by controlling the power supply amount by the control board 32.
In the SMA wire 10, temperature hysteresis appears between when the temperature is raised and when it is lowered, but this can be dealt with by correcting with software or the like.

  Next, a method for controlling the drive module 1 will be described.

  The drive module 1 having the above-described configuration can be autofocused by the control board 32 by the method shown in FIGS.

First, as shown in FIG. 7, a calibration operation is performed each time the electronic device is turned on. That is, the SMA wire 10 is energized to contract the SMA wire 10 to the transformation end point and move the lens frame 4 to the maximum, and then the energization to the SMA wire 10 is stopped to lower the temperature of the SMA wire 10. The SMA wire 10 is extended and deformed to return the lens frame 4 to the original reference position (lower reference position). At this time, as shown in FIG. 8, the resistance detection means 320 detects the maximum value R _max , the minimum value R _local-min , the maximum value R _local-max, and the minimum value R _min of the electric resistance of the SMA wire 10, respectively. The movable range of the lens frame 4 is calculated based on the maximum value R _local-max and the minimum value R _min described above.

More specifically, when the SMA wire 10 is energized while gradually increasing the input power from the non-energized state by the energizing unit 322 while detecting the electric resistance value of the SMA wire 10 by the resistance detecting unit 320, first, the SMA As the wire 10 is heated, the electrical resistance value of the SMA wire 10 increases monotonously as shown in FIG. When the electrical resistance value of the SMA wire 10 reaches the maximum value R _max that is the transformation start point, the SMA wire 10 contracts (transforms), the slack of the SMA wire 10 gradually decreases, and the electrical resistance of the SMA wire 10 decreases. As shown in FIG. 9, the resistance value switches from monotonically increasing to monotonically decreasing. At this time, the electrical resistance values (maximum values R _max , R _max ′) at the transformation start points A, A ′ are detected by the resistance detection means 320.

Subsequently, when the SMA wire 10 is heated until the SMA wire 10 is not loosened, the contraction of the SMA wire 10 is stopped, and the electric resistance value of the SMA wire 10 is switched from monotonically decreasing to monotonically increasing as shown in FIG. . At this time, the resistance detection means 320 detects the electric resistance value (minimum value R _local-min ) at the switching point (minimum point B).

Thereafter, when the SMA wire 10 contracts again and the distal end key portion 4D1 is pressed upward, and the lens frame 4 moves upward against the elastic restoring force of the coil spring 34, the upper leaf spring 6 and the lower leaf spring 7, The electrical resistance value of the SMA wire 10 is switched from monotonic increase to monotonic decrease as shown in FIG. At this time, the resistance detection means 320 detects the electrical resistance value (maximum value R _local-max ) at the switching point (maximum point C).

Thereafter, when the SMA wire 10 reaches the transformation end point, the electrical resistance value of the SMA wire 10 is switched from monotonically decreasing to monotonically increasing. At this time, the resistance detection means 320 detects the electrical resistance value (minimum value R _min ) at the switching point (minimum point D).

When the SMA wire 10 is not slack, as shown in FIG. 9, when the SMA wire 10 is energized while gradually increasing the input power from the non-energized state by the energizing means 322, first, the SMA wire 10 is used. The electric resistance value of 10 increases monotonously and then. When the SMA wire 10 contracts and the lens frame 4 moves upward against the elastic restoring force of the coil spring 34, the upper leaf spring 6 and the lower leaf spring 7, the electrical resistance value is switched from monotonically increasing to monotonically decreasing. . At this time, the electrical resistance value (maximum value R _max ″) at the switching point (transformation start point A ″) is detected by the resistance detection means 320.

Next, the focal point is searched by moving the lens frame 4 over the entire movement range by gradually decreasing the electric resistance of the SMA wire 10 in a constant width. In this case, to generate a command value R _t by command value generation means 321 described above, the resistance detecting means 320 based on the command value R _t while feeding back the detected value R of the resistance value of the SMA wire 10 by energizing means 322 To energize the SMA wire 10.

More specifically, first, a reference value R ₀ is set. Specifically, when the minimum point B appears in the function (shown in FIG. 9) representing the electrical resistance value with the input power value as an independent variable before the lens frame 4 starts moving in the resistance detection step described above, The electric resistance value (maximum value R _local-max ) at the maximum point C appearing after the minimum point B is set as a reference value R ₀ . On the other hand, when the minimum point B does not appear in the function shown in FIG. 9 before the lens frame 4 starts to move in the resistance detection step, the maximum value R _max ″ (= maximum value R _local-max ) is used as the reference value R. _Set to ₀ .

Next, the first command value R _{t (0)} is set by the command value generating means 321. Specifically, the above-described reference value _R0 is set as the first command value _{Rt (0)} . Subsequently, the SMA wire 10 is energized by the energization unit 322 so that the detection value R by the resistance detection unit 320 matches the command value R _{t (0)} . Then, an image is captured and stored when the detection value R detected by the resistance detection means 320 matches the command value R _{t (0)} (reference value R ₀ ). Thereby, an image in a state where the lens frame 4 is at the reference position is acquired.

Next, the command value Rt _(n) is reduced stepwise by the command value generation means 321 with a constant change width ΔR so that the lens frame 4 moves intermittently with a constant width. Specifically, first, a command value R _{t (1)} is set by the command value generation means 321. As the command value R _{t (1)} , the first command value R _{t (0)} described above, that is, a value (R ₀ −ΔR) obtained by subtracting the change width ΔR from the reference value R ₀ is set. The change width ΔR is a change width of the electric resistance value according to the movement amount of the lens frame 4 with a certain width, and can be set as appropriate. Subsequently, the SMA wire 10 is energized (heated) by the energizing means 322 so that the detection value R by the resistance detecting means 320 coincides with the command value _{Rt (1)} . Then, when the detection value R detected by the resistance detection unit 320 matches the command value R _{t (1)} (= R ₀ −ΔR), an image is captured and stored.

Thereafter, the command value generation means 321 sets a value (R ₀ −2 · ΔR) obtained by subtracting the change width ΔR from the previous command value R _{t (1)} (R ₀ −ΔR) as the command value R _{t (2).} The SMA wire 10 is energized (heated) by the energizing means 322 so that the detection value R by the resistance detecting means 320 coincides with the command value _{Rt (2),} and the detected value R by the resistance detecting means 320 becomes the command value. An image is captured and stored at the time when it matches R _{t (2)} (= R ₀ −2 · ΔR), and these processes are repeated. That is, a value (R ₀ −n · ΔR) obtained by subtracting the change width ΔR from the previous command value (R ₀ − (n−1) · ΔR) by the command value generation unit 321 is set as the command value R _{t (n).} The SMA wire 10 is energized (heated) by the energizing means 322 so that the detected value R by the resistance detecting means 320 matches the command value R _{t (n),} and the detected value R by the resistance detecting means 320 is When the value R _{t (n)} (R ₀ −n · ΔR) coincides, an image is captured and stored, and such processing is repeated until the command value R _{t (n)} reaches the minimum electric resistance value R _min .

Next, after the image at the last command value _{Rt (n)} is captured and stored, the focal point is searched based on all the stored images to determine the in-focus position.
Then, the electrical resistance value R _AF at the in-focus position is set as the command value R _{t (AF)} by the command value generation unit 321 so that the detection value R by the resistance detection unit 320 matches the command value R _{t (AF).} The energization means 322 controls (cools) the energization of the SMA wire 10, and the detection value R by the resistance detection means 320 matches the command value R _{t (AF)} (R _AF ), thereby completing the autofocus operation.

In the drive module 1 described above, as shown in FIG. 9, if the amount of slack of the SMA wire 10 is different, the transformation start points A and A ′ vary, but the above maximum point C is the amount of slack of the SMA wire 10. Even if they are different, they are constant. Therefore, by generating the command value R _{t (n)} using the electric resistance value R _local-max at the _local maximum point C as the reference value R ₀ , the lens frame 4 can be used even when the amount of slack of the SMA wire 10 varies. The movement start reference point becomes constant. Thereby, the movement start reference point of the lens frame 4 can be stabilized, individual differences in drive accuracy can be suppressed, and autofocus accuracy can be improved.

Further, when there is no slack in the SMA wire 10, the minimum point B does not appear as shown in FIG. Therefore, when the minimum point B does not appear, if the maximum value R _max ″ is set as the reference value R ₀ , the maximum value R _max ″ coincides with the above-described maximum value R _local-max, and therefore the movement start reference of the lens frame 4 The point becomes the same reference point as when the SMA wire 10 is slack, and the movement start reference point of the lens frame 4 can be stabilized.

  The autofocus operation in the drive module 1 described above searches the focal point by moving the lens frame 4 over the entire movement range by decreasing the electrical resistance of the SMA wire 10 in a stepwise manner, and then the SMA wire 10. The electrical resistance of the SMA wire 10 is gradually increased as shown in FIG. 10 to gradually move the lens frame 4 over the entire movement range. The lens frame 4 may be moved to the in-focus position by lowering the electrical resistance of the SMA wire 10 after searching the focal point.

  Furthermore, as shown in FIGS. 11A and 11B, the lens frame 4 is moved by focusing the SMA wire 10 by energizing the SMA wire 10 and gradually decreasing or increasing the electrical resistance of the SMA wire 10. After the search and the focus is detected, the position of the lens frame 4 may be finely adjusted by moving up and down the electrical resistance of the SMA wire 10 by a hill climbing method, and the lens frame 4 may be moved to the in-focus position.

Next, an electronic apparatus according to an embodiment of the present invention will be described.
12A and 12B are perspective external views of the front surface and the back surface of the electronic apparatus according to the embodiment of the present invention. FIG.12 (c) is FF sectional drawing in FIG.12 (b).

The camera-equipped mobile phone 20 of this embodiment shown in FIGS. 12A and 12B is an example of an electronic device including the drive module 1 of the above-described embodiment.
The camera-equipped mobile phone 20 includes a known mobile phone device configuration inside and outside the cover 22 such as a reception unit 22a, a transmission unit 22b, an operation unit 22c, a liquid crystal display unit 22d, an antenna unit 22e, and a control circuit unit (not shown). ing.

  Further, as shown in FIG. 12B, a window 22A that transmits external light is provided in the cover 22 on the back surface side on which the liquid crystal display portion 22d is provided, and as shown in FIG. The drive module 1 of the first embodiment is installed so that the opening 11A of the drive module 1 faces the window 22A of the cover 22 and the axis M is along the normal direction of the window 22A.

  According to such a configuration, the scan interval is constant, and high-precision autofocus is possible. In addition, since the number of steps with respect to the required movement amount is constant, it is possible to provide a high-performance camera-equipped mobile phone 20 that can shorten the time until autofocusing is completed.

The embodiments of the drive module, the electronic device, and the drive module control method according to the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and may be appropriately selected without departing from the scope of the present invention. It can be changed.
For example, in the present embodiment, the upper fixing pins 13A and 14A and the lower fixing pins 13B and 14B are inserted through the upper plate spring 6 and the lower plate spring 7 which are plate spring members for urging the lens frame 4, Although the example in the case of carrying out the heat crimping of the front-end | tip part of these fixing pins was demonstrated, the fixing method of a spring member is not limited to this. For example, it may be fixed by ultrasonic caulking or the like, or a spring member may be bonded to the lens frame 4 or the module frame 5. According to this structure, a large bonding area can be secured, so that a large strength can be obtained even if an adhesive is used. Furthermore, the spring member in the present invention is not limited to a leaf spring, and may be a spring member having another shape.

In the above description, the module frame 5 has been described as a substantially rectangular member as a whole, but is not limited to a substantially rectangular shape, and may be a polygonal shape.
In the above description, the SMA wire 10 is provided as a shape memory alloy body. However, the shape memory alloy body in the present invention is not limited to a wire shape, and for example, a shape memory of another shape such as a plate shape. An alloy body may be sufficient.

  In the above description, the example of the camera-equipped mobile phone is described as the electronic device using the drive module, but the type of the electronic device is not limited to this. For example, it can be used for other optical devices such as a digital camera and a camera built in a personal computer.

  In addition, in the range which does not deviate from the main point of this invention, it is possible to replace suitably the component in above-mentioned embodiment with a well-known component, and you may combine the above-mentioned modification suitably.

DESCRIPTION OF SYMBOLS 1 ... Drive module 4 ... Lens frame 5 ... Module frame (support body) 6 ... Upper leaf | plate spring (spring member) 7 ... Lower leaf | plate spring (spring member) 10 ... SMA wire (shape memory alloy body, drive means) 20 ... Camera Attached mobile phone (electronic equipment) 32 ... Control board (control means) 50 ... Lens

Claims (5)

A support;
A driven body provided so as to be capable of reciprocating along a fixed direction with respect to the support;
A spring member for elastically holding the driven body;
Drive means having a shape memory alloy wire locked to the driven body, and moving the driven body against the restoring force of the spring member when the shape memory alloy wire is deformed by heat generated by energization When,
Control means for performing drive control of the drive means by setting a command value of electrical resistance of the shape memory alloy wire and controlling energization to the shape memory alloy wire;
A drive module comprising:
The control means includes an energizing means for energizing the shape memory alloy wire, a resistance detecting means for detecting an electrical resistance value of the shape memory alloy wire, and an electric resistance value corresponding to the amount of movement of the driven body Command value generation means for generating the command value by subtracting the change width of the reference value from the reference value,
While the electric resistance value of the shape memory alloy wire is detected by the resistance detecting means, the shape memory alloy wire is energized while gradually increasing the input power by the energizing means, and the driven body starts to move. When the minimum point appears in the function representing the electrical resistance value with the input power value as an independent variable before, the command value generating means uses the electrical resistance value at the maximum point appearing after the minimum point as the reference value. A drive module characterized by generating a value. The drive module according to claim 1, wherein
When the minimum point does not appear before the driven body starts to move, the command value generating means generates the command value using the maximum value of the electric resistance value as the reference value. .   An electronic apparatus comprising the drive module according to claim 1. A support;
A driven body provided so as to be capable of reciprocating along a fixed direction with respect to the support;
A spring member for elastically holding the driven body;
Drive means having a shape memory alloy wire locked to the driven body, and moving the driven body against the restoring force of the spring member when the shape memory alloy wire is deformed by heat generated by energization When,
Control means for performing drive control of the drive means by setting a command value of electrical resistance of the shape memory alloy wire and controlling energization to the shape memory alloy wire;
A drive module control method comprising:
A resistance detection step of energizing the shape memory alloy wire while gradually increasing input power while detecting the electrical resistance value of the shape memory alloy wire;
When a minimum point appears in a function representing an electrical resistance value with the input power value as an independent variable before the driven body starts moving in the resistance detection step, the electrical resistance value at the maximum point appearing after the minimum point A command value generation step for generating the command value by subtracting a change width of the electric resistance value according to the amount of movement of the driven body from the reference value,
A drive module control method comprising: The method of controlling a drive module according to claim 4,
In the command value generation step, when the minimum point does not appear before the driven body starts moving, the command value is generated using the maximum value of the electric resistance value as the reference value. Control method for driving module.

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