JP5565543B1 - Driving device and imaging device - Google Patents

Abstract

  The drive device (1) of the present invention feeds power received by the electrode terminals (22, 23) to the electrode portions (31a, 31b) of the electromechanical transducer (31) via the electrode springs (24a, 24b). The mechanical energy by the electromechanical transducer (31) is transmitted to the drive shaft (32), and the electrode springs (24a, 24b) and the electrode portions (31a, 31b) of the electromechanical transducer (31). And a conductive member formed based on a conductive paste or a conductive adhesive (27) so as to straddle the electrode springs (24a, 24b) and the electrode portions (31a, 31b). The imaging device (100) of the present invention uses this driving device (1).

Description

  The present invention relates to a driving device suitably used for an imaging device that can be mounted on, for example, a mobile phone, and an imaging device using the driving device.

  2. Description of the Related Art Conventionally, as a driving device that is suitably used for an imaging device that can be mounted on, for example, a mobile phone, a driving device called SIDM (Smooth Impact Drive Mechanism, “SIDM” is a registered trademark) is known. This SIDM drive device includes a piezoelectric element that is an electromechanical conversion element, a drive shaft that is joined to one end of the piezoelectric element, and a moving body that is frictionally engaged with the outer periphery of the drive shaft. In such a SIDM drive device, the expansion and contraction of the piezoelectric element is transmitted to the drive shaft, and the moving body engaged with the drive shaft with a predetermined frictional force is applied when the piezoelectric element is expanded and contracted. Drive by using the speed difference. More specifically, in such a drive device, for example, by slowly extending the drive shaft, the moving body frictionally engaged with the drive shaft is also driven and moved, while the predetermined frictional force is exceeded. When the drive shaft is instantaneously reduced, the moving body is left in the extended position. By repeatedly performing such expansion and contraction of the drive shaft, the drive device can drive the movable body in the axial direction of the drive shaft.

  As such a driving device, for example, Patent Document 1 discloses a driving device in which an electrode terminal is bridge-bonded to a piezoelectric element with a conductive adhesive. Further, for example, Patent Document 2 discloses a driving device in which electrode terminals are soldered to piezoelectric elements.

  By the way, in the configuration in which the piezoelectric element and the electrode terminal are bridge-bonded with a conductive adhesive as in Patent Document 1, reliable bonding may not be obtained depending on the curing conditions and the like, and ensuring of reliability is insufficient. It is.

  Further, in the configuration in which solder bonding is performed as in Patent Document 2 described above, stress concentrates on the boundary between the solder and the electrode surface provided on the piezoelectric element, and the solder and the piezoelectric element are detached when subjected to an impact caused by dropping, for example. Cause damage.

JP 2006-31794 A International Publication WO2011 / 055504

  The present invention has been made in view of the above circumstances, and its purpose is to drive that can reliably connect the piezoelectric element and the electrode terminal and can reliably maintain the connection state between the piezoelectric element and the electrode terminal. An apparatus and an imaging device are provided.

  The drive device according to the present invention feeds the power received by the electrode terminal to the electrode portion of the electromechanical transducer through an electrode spring, and transmits the mechanical energy by the electromechanical transducer to the drive shaft. A conductive member formed on the basis of a conductive paste or a conductive adhesive is provided at a contact portion between the electrode spring and the electrode portion of the electromechanical conversion element so as to straddle the electrode spring and the electrode portion. And the imaging device concerning this invention uses this drive device.

  The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

It is a perspective view of the drive device in an embodiment. It is a disassembled perspective view of the drive device shown in FIG. It is a perspective view of the drive main body used for the drive device shown in FIG. It is a perspective view of the holding member used for the drive device shown in FIG. It is a perspective view of the movable body main-body part used for the drive device shown in FIG. It is a top view of the mobile body main-body part shown in FIG. It is a perspective view of the guide spring used for the drive device shown in FIG. It is a top view of the guide spring shown in FIG. It is a top view in the state where the cover of the drive unit shown in FIG. 1 was removed. It is explanatory drawing of the connection part of the electrode terminal and piezoelectric element in the drive device shown in FIG. It is a perspective view of the connection state of the said mobile body main-body part and the said guide spring in the drive device shown in FIG. It is explanatory drawing at the time of connecting the said mobile body main part and guide spring in a drive device shown in FIG. 1 using a jig | tool. It is sectional drawing which abbreviate | omitted the cover of the imaging device using the drive device shown in FIG. It is the graph which represented the resistance value accompanying a time-dependent about each kind of film-forming given to the electrode spring. It is explanatory drawing of other embodiment of the connection of the electrode terminal and piezoelectric element by the electrode spring used for the drive device shown in FIG. It is explanatory drawing of the state which connected the electrode terminal and the piezoelectric element using the electrode spring of other embodiment shown in FIG. It is explanatory drawing of the state which connected the electrode terminal and the piezoelectric element using the electrode spring of other embodiment.

  Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted suitably. In the present specification, when referring generically, it is indicated by a reference symbol without a suffix, and when referring to an individual configuration, it is indicated by a reference symbol with a suffix. In the following description, the X direction shown in FIGS. 1 to 5, 7, 10 to 13, and 16 is the upper side, and the Y direction is the lower side.

  1 to 13, the driving device 1 of the present embodiment is suitably used for an imaging device that can be mounted on, for example, a mobile phone. As shown in FIGS. 1 and 2, the driving device 1 of this embodiment includes a holding member 2, electrode terminals 22 and 23 held by the holding member 2, a driving main body 3, a moving body 4, and electrode terminals. Electrode springs 24a and 24b and a conductive member 27 (refer to FIG. 10) for connecting the motors 22 and 23 and the drive main body 3 and a cover 8 are provided.

  The holding member 2 is a base member that holds and supports the drive main body 3, and is formed of a resin material such as LCP (liquid crystal polymer), and as shown in FIG. It is formed by injection molding in a shape in which is inserted. The holding member 2 of this embodiment is a cylindrical body having a rectangular outer periphery and having a circular through hole 20g serving as an optical path at the center.

  The holding member 2 includes a first support column 20a that is erected along the X direction from the upper surface (one surface) 2e of the cylindrical body at the first corner 2a (lower left side in FIG. 4). The holding member 2 includes a drive main body holding portion 21 that holds the drive main body portion 3 inside the first support pillar 20a in the first corner portion 2a.

  The drive main body holding portion 21 is formed so as to be recessed in a cylindrical shape with a predetermined depth from the upper surface 2 e of the holding member 2.

  As shown in FIG. 4, the holding member 2 is provided with the cylinder on each of the second corner portion 2 b on the right front side, the third corner portion 2 c on the right rear side, and the fourth corner portion 2 d on the left rear side. A second support column 20b, a third support column 20c, and a fourth support column 20d are provided so as to stand up along the X direction from the upper surface (one surface) 2e of the cylindrical body. The third support pillar 20c is formed with a restricting portion receiving groove 29 for receiving a rotation restricting portion 61a of the moving body 4 described later so as to be movable in the vertical direction. In addition, these 1st thru | or 4th corners 2a-2d are integrally formed with the said cylindrical body in this embodiment.

  The electrode terminal is a member for receiving electric power transmitted to an electromechanical conversion element (in the example, the piezoelectric element 31) to be described later in the drive main body unit 3, and includes the first electrode terminal 22 and the second electrode terminal 23. I have. The first electrode terminal 22 and the second electrode terminal 23 have the same configuration, and a holding member is provided on both sides of the driving body holding portion 21 at the first corner 2a of the holding member 2 at the tip thereof. 2 is provided with projecting pieces 22a and 23a arranged so as to project upward.

  The first and second electrode terminals 22 and 23 are each embedded in the holding member 2 at the intermediate portions thereof, and the base ends of the first and second electrode terminals 22 and 23 are respectively external surfaces of the holding member 2. The external connection terminals 22b and 23b are provided. Then, a circuit board or connector of a mobile phone (not shown) on which the driving device 1 is mounted and the external connection terminals 22b and 23b are connected to each other.

  In this embodiment, as shown in FIG. 10, the external connection terminal 22b of the first electrode terminal 22 and the external connection terminal 23b of the second electrode terminal 23 are flush with the lower surfaces of the external connection terminals 22b and 23b, respectively. It bends and forms through the step part. With this configuration, the external connection terminal 22b of the first electrode terminal 22 and the external connection terminal 23b of the second electrode terminal 23 can be connected to the circuit board so as to be energized, for example, by being placed on the circuit board of a mobile phone.

  As shown in FIG. 3, the drive main body 3 includes a piezoelectric element 31 that is an example of an electromechanical conversion element that expands and contracts in the axial direction, a drive shaft 32 that is connected to one end of the piezoelectric element 31, and a piezoelectric element 31. And a weight 33 connected to the other end.

  The weight 33 is a member for generating displacement due to expansion and contraction of the piezoelectric element 31 mainly on the drive shaft 32 side, preferably only on the drive shaft 32 side. In this embodiment, the weight 33 is formed of a material having a high specific gravity such as tungsten or a tungsten alloy.

  The weight 33 has a cylindrical shape formed so that the outer diameter protrudes from the outer periphery of the piezoelectric element 31 to the outer periphery over the entire periphery.

  The piezoelectric element 31 is an example of an electromechanical conversion element. This electromechanical transducer is an element that converts input electrical energy into mechanical energy that expands and contracts, that is, mechanical motion. For example, a piezoelectric that converts input electrical energy into mechanical elastic motion by the piezoelectric effect. Elements and the like. In the present embodiment, as described above, the piezoelectric element 31 is used as the electromechanical conversion element, and the piezoelectric element 31 includes, for example, a laminated body and a pair of external electrodes.

  The laminated body is formed by alternately laminating a plurality of thin film (layered) piezoelectric layers made of a piezoelectric material and a conductive thin film (layered) internal electrode layer. In the present embodiment, the laminate has a quadrangular prism shape, but is not limited to this, and may be, for example, a polygonal column shape or a cylindrical shape.

  In the plurality of internal electrode layers, the plurality of anode layers among the plurality of internal electrode layers reach one side of the outer peripheral side surface in the multilayer body, and the plurality of cathode layers reach the other side of the outer peripheral side surface in the multilayer body. Are extended so that the front ends of the respective layers face each other on a pair of outer peripheral side surfaces facing each other. A pair of external electrodes 31a and 31a supply the electric energy to the laminated body, and are formed on the pair of outer peripheral side surfaces of the laminated body by a sputtering method such as silver along the laminating direction. The plurality of internal electrodes are sequentially and alternately connected so as to be connected in parallel.

Examples of the piezoelectric material include lead zirconate titanate (so-called PZT), crystal, lithium niobate (LiNbO ₃ ), potassium tantalate niobate (K (Ta, Nb) O ₃ ), barium titanate (BaTiO ₃ ), Inorganic piezoelectric materials such as lithium tantalate (LiTaO ₃ ) and strontium titanate (SrTiO ₃ ).

  The lower end surface of the piezoelectric element 31 is bonded to the upper end surface of the weight 33 with an adhesive such as an epoxy adhesive. In this embodiment, resinous beads having a diameter of about 5 μm are mixed in the epoxy adhesive in order to prevent a short circuit with the weight and stabilize the thickness of the adhesive layer.

  The drive shaft 32 is formed of carbon fiber-reinforced plastic (CFRP) in which carbon fibers are arranged in the axial direction and formed into a cylindrical shape with a resin. The drive shaft 32 of the present embodiment is formed so that the outer diameter protrudes from the outer periphery of the piezoelectric element 31 to the outer periphery over the entire periphery.

  The lower end surface of the drive shaft 32 is bonded to the upper end surface (one end) of the piezoelectric element 31 with an adhesive. This adhesive may be the same as the adhesive that bonds the piezoelectric element 31 and the weight 33.

  An adhesive (fillet) protruding from the joint surface between the drive shaft 32 and the piezoelectric element 31 is formed on the piezoelectric element 31 side. As a result, the entire region of the drive shaft 32 (the entire region in the axial direction on the outer peripheral surface) can be used for sliding with the moving body 4, and a large stroke can be realized with the short drive shaft 32.

  As shown in FIG. 13, the drive main body 3 is inserted into the drive main body holding portion 21 of the holding member 2 from the weight 33 side, and the bottom surface of the drive main body holding portion 21 and the weight 33 are bonded by an adhesive (not shown). Are bonded, and the drive main body 3 is fixed in the drive main body holding portion 21. With this configuration, in this embodiment, the lower end surface (the other end) of the piezoelectric element 31 is indirectly attached to the holding member 2 via the weight 33.

  Note that the weight 33 may be omitted when the other end of the piezoelectric element 31 can be directly attached to the holding member 2 so that the same function as that of the weight 33 can be exhibited. .

  In this state, the axial direction of the drive shaft 32 and the axial direction of the holding member 2 coincide with each other. As shown in FIG. 9, both side surfaces of the piezoelectric element 31 having the external electrodes 31 a and 31 b are arranged on the holding member 2. The first corner 2a is disposed substantially parallel to the direction from the first corner 2a toward the center O1. In this embodiment, the both side surfaces are arranged in parallel to the line P on both sides of the line P connecting the center O1 of the holding member 2 and the axis O2 of the drive shaft 32.

  The axial direction of the drive shaft 32 and the protruding piece 22a of the first electrode terminal 22 and the protruding piece 23a of the second electrode terminal 23 are substantially parallel.

  Next, the electrode springs 24a and 24b will be described. As shown in FIGS. 9 and 10, the electrode spring includes a first electrode spring 24 a connecting the first external electrode 31 a of the piezoelectric element 31 and the first electrode terminal 22, and a second external electrode 31 b of the piezoelectric element 31. A second electrode spring 24b connected to the second electrode terminal 23;

  The first electrode spring 24a and the second electrode spring 24b have the same configuration, and are each composed of a torsion coil spring having a coil portion 25a wound with a wire, a first foot portion 25b, and a second foot portion 25c. Has been.

  In this embodiment, the coil portion 25a has an inner diameter R that is slightly smaller than the width L of the protruding piece 22a of the first electrode terminal 22 (in FIG. 9, it is represented by the same width for the sake of drawing). The coil portion 25a is pushed into the inside (core portion). Thus, the coil part 25a is comprised so that it may be in the state which both contacted reliably by pushing the protrusion piece 22a into the inside of the coil part 25a.

  The first leg portion 25b is provided to project radially outward from the coil portion 25a at the upper end (one end) in the axial direction of the coil portion 25a. The second leg portion 25c protrudes radially outward from the coil portion 25a in the opposite direction to the first foot portion 25b at the lower end (the other end) in the axial direction of the coil portion 25a.

  In this embodiment, each of the first electrode spring 24a and the second electrode spring 24b is made of phosphor bronze having high electrical conductivity, and the surface is plated with a highly corrosion-resistant material such as gold or platinum. Etc. are formed.

  In addition, the 1st electrode spring 24a and the 2nd electrode spring 24b are not restricted to what is formed from phosphor bronze, For example, they can also be formed from stainless steel and a piano wire, and can be changed and used suitably. Further, although gold or platinum is formed on each surface of the first electrode spring 24a and the second electrode spring 24b, gold or platinum may not be formed.

  However, as shown in FIG. 14, the electrode spring formed with gold or platinum does not increase in resistance value over time and does not deteriorate (FIG. 14 shows the time-dependent change in the electrode spring formed with gold. Resistance value (♦) is shown.) On the other hand, the white (■), phosphor bronze (、), Sn plating (□), and Ni plating (x) deteriorate with increasing resistance over time. Therefore, the surfaces of the first electrode spring 24a and the second electrode spring 24b are preferably formed of gold or platinum. FIG. 14 shows the deterioration (resistance value) over time under the conditions of a temperature of 85 ° C. and a humidity of 85%. The horizontal axis in FIG. 14 is the elapsed time, and the vertical axis is the resistance value.

  As shown in FIG. 10, the first electrode spring 24 a is configured such that the protruding piece 22 a of the first electrode terminal 22 is pushed into the coil portion 25 a and the first foot portion 25 b is brought into contact with the first external electrode 31 a of the piezoelectric element 31. In contact therewith, the second foot 25c is locked to a spring locking portion 26 (shown in FIG. 9) provided on the holding member 2.

  In this state, in the first electrode spring 24a, a torsional force is accumulated in the coil portion 25a, and the first foot 25b presses the first external electrode 31a of the piezoelectric element 31 by the torsional force.

  In the second electrode spring 24b, the protruding piece 23a of the second electrode terminal 23 is pushed into the coil portion 25a, the first foot portion 25b contacts the second external electrode 31b of the piezoelectric element 31, and the second foot portion 25c is held. It is locked to the spring locking portion 26 (see FIG. 9) of the member 2.

  In this state, in the second electrode spring 24b, a torsional force is accumulated in the coil portion 25a, and the first foot 25b presses the second external electrode 31b of the piezoelectric element 31 by the torsional force.

  Next, the conductive member will be described. In this embodiment, the conductive member is formed from a conductive adhesive 27. The conductive adhesive 27 of this embodiment is formed from an epoxy adhesive mixed with silver particles.

  The conductive adhesive 27 is applied to the first leg portions 25b at the contact points between the first leg portions 25b of the first electrode spring 24a and the second electrode spring 24b and the first external electrode 31a of the piezoelectric element 31. And the first external electrode 31a are applied and cured. The conductive adhesive 27 is applied to the portion between the contact portion and the coil portion 25a, and the contact portion between the coil portion 25a and the protruding piece 22a of the first electrode terminal 22, and the coil portion 25a and the protruding piece. It is applied to each of 22a and cured.

  The conductive member is not limited to one formed from the conductive adhesive 27, and can be formed from, for example, a conductive paste obtained by mixing an adhesive light polymer material and silver particles. You may form by apply | coating to a location and making it harden | cure.

  As a result, in addition to the first electrode spring 24a and the second electrode spring 24b, the conductive adhesive 27 is applied to the first external electrode 31a and the first electrode terminal 22 of the piezoelectric element 31, and the second external electrode 31b and the second electrode terminal 23. Are connected so as to be energized, and the two are more reliably connected.

  In this embodiment, a reinforcing adhesive 28 for reinforcing the adhesive strength of the conductive adhesive 27 is provided. More specifically, the reinforcing adhesive 28 is formed of, for example, a UV adhesive. The reinforcing adhesive 28 is disposed so as to cover the surface of the conductive adhesive 27.

  Next, the moving body 4 will be described. The moving body 4 is engaged with the drive shaft 32 with a predetermined frictional force, and slides along the axial direction of the drive shaft 32. As shown in FIG. 2, the moving body 4 of the present embodiment includes a metal cylindrical moving body main body 5 and a guide spring (metal plate body) 6 that is separate from the moving body main body 5. . In this embodiment, the movable body main body 5 is made of, for example, stainless steel and has a thickness of 0.05 mm to 0.3 mm and is formed by drawing. Stainless steel is a material that is inexpensive, has good moldability, good durability, and good driving performance among metal materials.

  As shown in FIGS. 5 and 6, the movable body main body 5 includes a lens holding portion 54 on the inner peripheral side, and the lens holding portion 54 has a lens barrel as a moved body having one or a plurality of lens groups 71. 7 (see FIG. 13). An adhesive groove 72 is provided on the side surface of the lens barrel 7, and the lens barrel 7 is adhered to the lens holding portion 54 by filling the adhesive groove 72 with an adhesive 73 (see FIG. 13).

  The movable body main body 5 includes a first sliding surface 51 that slides on the drive shaft 32 on a part of the outer peripheral surface. In the present embodiment, the first sliding surface 51 is formed in a flat plate shape with a predetermined width in the circumferential direction over the entire axial direction when molding the movable body main body 5. To form a flat surface. For this reason, when the movable body main body 5 slides on the drive shaft 32, the movable body main body 5 can slide while maintaining a certain posture without being inclined with respect to the drive shaft 32.

  The mobile body 5 includes a first flange 52 formed at the lower end so as to protrude radially inward, and a second flange 53 formed at the upper end so as to protrude radially outward. Thus, the strength of the movable body main body 5 is increased.

  The upper surface of the first flange 52 forms a lens barrel mounting portion 52a. When the lens barrel 7 is held by the lens holding portion 54 as shown in FIG. 13, the lens barrel mounting portion 52a has a lens barrel. 7 is arranged such that the axis of the movable body main body 5 and the optical axis of the lens group 71 of the lens barrel 7 are aligned without tilting each other.

  As described above, since the movable body main body 5 is a metal tube, it has high durability and durability against wear, and since it is a thin metal tube, it is possible to increase the diameter of the lens 71 held inside. Become. Since the drive shaft 33 is driven in direct contact with the moving body main body 5, the moving body main body 5 is compared with a configuration in which a portion that frictionally engages the driving main body 3 is provided separately from a portion that holds the lens group 71. The diameter of the lens group 71 held inside can be increased.

  In this embodiment, the guide spring 6 is made of stainless steel, for example, and is formed with a thickness of 0.1 mm to 0.3 mm. 7 and 8, the guide spring 6 includes an arc portion 61, a guide portion 62 formed on one end side of the arc portion 61, and a pressing piece 63 formed on the other end side of the arc portion 61. Is provided.

  The arc portion 61 includes a rotation restricting portion 61a at a position spaced apart from the guide portion 62 by approximately 180 ° in the circumferential direction. The rotation restricting portion 61a is for restricting the rotation of the movable body 4 around the axis of the drive shaft 32, and includes a restricting frame portion 61b and a hemispherical protrusion 61c formed on the restricting frame portion 61b. .

  The restriction frame portion 61b is formed so that a part of the arc portion 61 protrudes radially outward in a rectangular shape.

  The protrusion 61c is formed so as to protrude outward from each of both outer side surfaces of the restriction frame portion 61b. Further, the outer width W1 (see FIG. 9) between the protrusions 61c is set to be slightly narrower than the inner width W2 (see FIG. 9) of the restricting portion receiving groove 29 of the holding member 2. In FIG. 9, for the convenience of drawing, the outer width W1 between the protrusions 61c and the inner width W2 of the restricting portion receiving groove 29 are represented by the same width.

  In the present embodiment, the arc portion 61 includes a narrow portion 61d having a narrower width than the other portions between one end (guide portion 62) and the rotation restricting portion 61a.

  The guide portion 62 is formed by bending a part of one end side of the arc portion 61 outward in the radial direction of the arc portion 61, and a second sliding surface 62 a that slides the drive shaft 32 is formed on one surface thereof. Prepare.

  The pressing piece 63 is formed so as to extend linearly from the other end of the arc portion 61 through a stepped portion, and includes a pressing portion 63 a that presses the drive shaft 32 at the tip portion. The pressing part 63a of the present embodiment is formed narrower than the first sliding surface 51 and the second sliding surface 62a.

  The guide spring 6 and the movable body main body 5 are fixedly connected by welding.

  More specifically, as shown in FIG. 11, the guide spring 6 and the movable body main body 5 are adjacent to each other in the first sliding surface 51 of the movable body main body 5 and the second sliding surface 62a of the guide spring 6. The guide spring 6 is wound around the outer periphery of the movable body main body 5.

  In this state, both of the first fixing portion 64a and the first fixing portion 64a spaced apart from the guide portion 62 in the arc portion 61 of the guide spring 6 by a predetermined distance, for example, as indicated by x in FIG. Further, resistance welding (spot welding) is performed at four positions spaced apart from each other between the second fixing portion 64b and the third fixing portion 64c on both sides of the rotation restricting portion 61a and the fourth fixing portion 64d in the vicinity of the boundary between the pressing piece 63. ) And laser welding or the like.

  In the present embodiment, the welding is performed by using the positioning jig 11 holding the rotation restricting portion 61a and the second sliding surface posture adjusting jig 12 holding the guide portion 62, as shown in FIG. Welding is performed after determining the positions of the body body 5 and the guide spring 6 and the attitude of the second sliding surface. At this time, for example, when the posture of the second sliding surface is set, the posture of the second sliding surface is easily set by the narrow portion 61 d of the arc portion 61.

  In the state fixed by this welding, as shown in FIG. 9, the first sliding surface 51 and the second sliding surface 62a are substantially perpendicular, and the first and second sliding surfaces 51, 62a are Both are L-shaped.

  In this way, the movable body main body 5 and the guide spring 6 are made of a metal such as stainless steel, and are joined by welding, so that the movable body main body 5 and the guide spring 6 can be firmly fixed. Since it can be fixed instantly, the manufacturing tact time can be greatly reduced.

  As shown in FIG. 9, the movable body 4 in which the movable body main body 5 and the guide spring 6 are connected has the rotation restricting portion 61 a inserted in the restricting portion receiving groove 29 of the holding member 2, and the drive shaft 32. Is arranged so as to be surrounded by the first sliding surface 51, the second sliding surface 62a, and the pressing portion 63a.

  Accordingly, the first sliding surface 51 is pressed against the outer periphery of the drive shaft 32 by the elastic force of the pressing piece 63, and the second sliding surface 62 a contacts the first sliding surface 51 on the outer periphery of the driving shaft 32. The movable body 4 is frictionally engaged with the drive shaft 32 by being pressed to a position that is spaced a predetermined distance in the circumferential direction.

  In this state, the pressing piece 63 is in a state extending from the second corner portion 2b of the holding member 2 to the first corner portion 2a. The first sliding surface 51 is perpendicular to a line P connecting the center O1 of the holding member 2 and the axis O2 of the drive shaft 32 when viewed from the upper side (one side) of the drive shaft 32 in the axial direction. Further, the second sliding surface 62a is in contact with the drive shaft 32 while being parallel to the line P and facing the second corner portion 2b between the fourth corner portion 2d and the drive shaft 32. It touches.

  Next, the cover 8 will be described with reference to FIGS. 1 and 2. The cover 8 of the present embodiment is formed into a box shape with one surface (lower surface) opened by drawing or pressing a stainless steel thin plate of 0.1 mm to 0.2 mm, for example. Through-hole 82 is provided. The through hole 82 has a shape corresponding to the shape of the optical path in the lens barrel 7 and is, for example, a circular shape.

  The cover 8 includes locking holes 84 on the four side walls 83 for locking to locking protrusions 20 f provided on the side surfaces of the holding member 2. In this embodiment, the number of the locking projections 20f is two, and the locking projections 20f are locked with the two locking holes 84 facing each other.

  The cover 8 is formed on the upper surface of the first support column 20a, the third support column 20c, and the fourth support column 20d of the holding member 2 and the upper surface of the second support column 20b. With the inner surface of the upper wall 81 in contact, the locking hole 84 and the locking projection 20f are locked.

  In this locked state, the upper surfaces of the mounting table 20e and the second support column 20b and the inner surface of the upper wall 81 of the cover 8 are bonded and bonded together with an adhesive.

  In the driving device 1 configured as described above, for example, as shown in FIG. 13, the lens barrel (imaging optical system) 7 is held by the lens holding portion 54 of the moving body 4, and the IR cut is formed on the lower surface side of the holding member 2. A sensor substrate 103 a having a filter 102 and an image sensor 103 is attached. Thereby, the imaging device 100 is formed.

  The image sensor 103 is an image of each component of R (red), G (green), and B (blue) according to the amount of light in an optical image of an object (subject) imaged by an imaging optical system (not shown) as a whole. It is an element that photoelectrically converts a signal and outputs it to a predetermined image processing circuit (not shown). The image sensor 103 is, for example, a CCD image sensor, a CMOS image sensor, or the like.

  The imaging optical system includes one or a plurality of lens groups (optical elements) including a lens group 71, and forms an optical image of an object on a light receiving surface of the imaging element 103. The lens group 71 is an optical element that moves along the optical axis among the one or more optical elements in such an imaging optical system. The lens group 71 may be a single lens or may include a plurality of lenses. The lens group 71 may be, for example, an optical system that moves along the optical axis to perform focusing (focusing), and, for example, an optical that moves along the optical axis to perform zooming (magnification). It may be a system. The optical image of the object is guided by the imaging optical system including the lens group 71 to the light receiving surface of the imaging element 103 along the optical axis, and the optical image of the object is captured by the imaging element 103. The

  For example, the external connection terminal 22b of the first electrode terminal 22 and the external connection terminal 23b (see FIG. 1 and the like) of the second electrode terminal 23 are arranged on the circuit board of the mobile phone and installed in the casing of the mobile phone. .

  When power (drive signal) is supplied from the drive circuit (not shown) provided in the mobile phone to the external connection terminal 22b of the first electrode terminal 22 and the external connection terminal 23b of the second electrode terminal 23, the drive main body 3 The piezoelectric element 31 expands and contracts in the axial direction, and the drive shaft 32 reciprocates by the expansion and contraction, and the moving body 4 moves in the axial direction (optical axis direction) of the drive shaft 32 by the reciprocation.

  More specifically, when a rectangular wave having a predetermined duty ratio is applied as a drive signal to the piezoelectric element 31, the displacement of the piezoelectric element 31 becomes a triangular wave, and when the amplitude is increased by changing the duty ratio of the rectangular wave ( Triangular wave-like expansion and contraction motions with different inclinations occur during expansion (when stretched) and when lowered (when contracted). The drive mechanism of the drive main body 3 utilizes this.

  For example, by slowly extending the drive shaft 32, the moving body 4 that is frictionally engaged with the drive shaft 32 also slides according to the extension, and instantly enough to exceed the frictionally engaged friction force, When the drive shaft 32 is contracted, the moving body 4 is left as it is at the position of the movement destination. By repeatedly expanding and contracting the drive shaft 32 in the axial direction, the moving body 4 slides in the axial direction of the drive shaft 32.

  When the moving body 4 slides on the drive shaft 32, the first sliding surface 51 and the second sliding surface 62a slide while being pressed against the driving shaft 32. It can move without changing its posture.

  Since the conductive adhesive 27 is disposed at the contact point between the electrode springs 24a and 24b and the external electrodes 31a and 31b of the piezoelectric element 31, the electrode springs 24a and 24a accompanying vibration (repetition of expansion and contraction) of the piezoelectric element 31 are provided. Wear of the external electrodes 31a and 31b due to 24b can be suppressed.

  Since the pressing portion 63a is formed to be narrower than the first sliding surface 51 and the second sliding surface 62a, for example, even when the pressing piece 63 is twisted, the drive shaft 32 is securely moved to the first sliding surface. The moving surface 51 and the second sliding surface 62a can be brought into line contact with each other, and the moving body 4 can move more reliably without changing its posture.

  When the moving body 4 tries to rotate around the axis of the drive shaft 32, any one of the protrusions 61c of the rotation restricting portion 61a comes into contact with the inner wall of the restricting portion receiving groove 29, so that the rotation of the moving body 4 is restricted. Is done. When the moving body 4 slides on the drive shaft 32 from the state in which the protrusion 61c is in contact with the inner wall of the restricting portion receiving groove 29, the protrusion 61c is formed in a hemispherical shape and makes point contact with the inner wall of the restricting portion receiving groove 29. Therefore, the movable body 4 can slide on the drive shaft 32 with almost no resistance due to the contact.

  In the above embodiment, the protruding pieces 22a and 23a of the electrode terminals 22 and 23 are inserted into the coil portions 25a of the electrode springs 24a and 24b. However, the present invention is not limited to this configuration, and can be changed as appropriate.

  FIG. 15 is an explanatory view of another embodiment of the connection between the electrode terminal and the piezoelectric element by the electrode spring used in the drive device shown in FIG. For example, as shown in FIG. 15, between the driving body holding portion 21 and the protruding piece 22 a of the first electrode terminal 22 in the holding member 2, and the protruding piece 23 a of the driving body holding portion 21 and the second electrode terminal 23. In between, the support protrusions 122 are respectively provided.

  The support protrusion 122 is inserted into the coil portion 25a of the first electrode spring 24a, the first foot portion 25b abuts on the first external electrode 31a of the piezoelectric element 31, and the second foot portion 25c is the first electrode. It contacts the protruding piece 22 a of the terminal 22. The support protrusion 122 is inserted into the coil portion 25a of the second electrode spring 24b, the first foot portion 25b is in contact with the second external electrode 31b of the piezoelectric element 31, and the second foot portion 25c is the second electrode terminal. 23 abuts against the protruding piece 23a.

  In the above-described embodiment, the electrode springs 24a and 24b are constituted by the torsion coil spring having the first leg portion 25b and the second leg portion 25c. However, the present invention is not limited to this configuration and can be changed as appropriate.

  FIG. 16 is an explanatory diagram of a state in which the electrode terminal and the piezoelectric element are connected using the electrode spring of another embodiment shown in FIG. For example, as shown in FIG. 16, the electrode springs 124 a and 124 b are configured by a conical coil spring including a substantially conical coil portion 125 a in a side view. The electrode springs 124a and 124b are formed by inserting the protruding pieces 22a and 23a of the electrode terminals 22 and 23 into the coil portion 125a from the small diameter portion side, and the outer periphery of the large diameter portion side on the outer electrodes 31a and 31b of the piezoelectric element 31. Abut.

  With this configuration, the drive main body 3 is placed on the outer peripheral side of the electrode springs 124a and 124b in a state where the protruding pieces 22a and 23a of the electrode terminals 22 and 23 are inserted into the coil portions 125a of the electrode springs 124a and 124b. From (between the electrode springs 124a and 124b), the external electrodes 31a and 31b of the piezoelectric element 31 and the outer periphery of the electrode springs 124a and 124b can be set in contact with each other, which facilitates assembly.

  Since the electrode springs 124a and 124b are disposed on the side of the drive shaft 32 of the drive main body 3 on the large diameter side, the movable body 4 (see FIG. 2) can hardly interfere with the electrode springs 124a and 124b. The overall height can be reduced. The conductive member 27 can be easily injected into the coil portion 125a, and the injection work can be facilitated. In addition, the coil portion 125a and the protruding pieces 22a and 23a of the electrode terminals 22 and 23 can be reliably connected.

  FIG. 17 is an explanatory diagram of a state in which the electrode terminal and the piezoelectric element are connected using the electrode spring of still another embodiment. As shown in FIG. 17, the electrode springs 224a and 224b are constituted by coil springs including a coil portion 225a having the same diameter over the entire length in the axial direction. The protruding pieces 222 a and 223 a of the electrode terminal are formed to be inclined toward the external electrodes 31 a and 31 b of the piezoelectric element 31. The electrode springs 224a and 224b are inserted into the coil portion 225a so that the protruding pieces 222a and 223a of the electrode terminals are inserted into contact with the protruding portions 222a and 223a, and the axial direction of the coil portion 225a is The tips are in contact with the external electrodes 31 a and 31 b of the piezoelectric element 31.

  Moreover, in the said embodiment, although the internal diameter of the coil part of an electrode spring is made slightly smaller than the width | variety of the protrusion piece of an electrode terminal, not only the thing of this form but the internal diameter of the coil part of an electrode spring is set to the electrode terminal. It may be the same as or larger than the width of the protruding piece. Even in this case, the coil portion and the protruding piece of the electrode terminal can be brought into contact with the elastic deformation of the electrode spring when the first leg portion of the electrode spring contacts the external electrode of the piezoelectric element.

  Further, although the piezoelectric element 31 is fixed to the holding member 2 via the weight 33, the side surface of the piezoelectric element 31 may be fixed to the holding member 2.

  The present specification discloses various aspects of the technology as described above, and the main technologies are summarized below.

  A drive device according to one aspect includes an electromechanical conversion element that converts electrical energy into mechanical energy that expands and contracts, and a drive shaft that is fixed to one end in the expansion and contraction direction of the electromechanical conversion element and that transmits the mechanical energy. An electrode terminal for receiving electric power transmitted to the electromechanical conversion element; and an electrode spring having a coil portion in contact with each of the electrode terminal and an electrode portion provided in the electromechanical conversion element; A conductive member formed on the basis of a conductive paste or a conductive adhesive so as to straddle the electrode spring and the electrode portion at a contact portion between the electrode spring and the electrode portion of the electromechanical conversion element; Prepare. For example, electric power for driving the electromechanical transducer is transmitted to the electrode terminal from a drive circuit for driving the drive device. For example, the conductive member is formed by applying and curing the conductive paste or the conductive adhesive.

  In such a drive device, an electrode spring having a coil portion is brought into contact with each of the electrode terminal and the electrode portion of the electromechanical conversion element, so that both can be reliably connected, for example, even when receiving an impact due to dropping The elastic state of the electrode spring can keep the electrode terminal and the electrode portion of the electromechanical transducer element connected to each other.

  Since the electrode spring is elastically connected to each of the electrode terminal and the electrode portion of the electromechanical conversion element, an error in manufacturing dimensions of each portion can be absorbed, and the electrode spring can be surely brought into contact.

  In addition, since the conductive member is disposed at the contact portion between the electrode spring and the electrode portion of the electromechanical conversion element, the electrode spring temporarily comes out of contact with the electrode terminal or the electrode portion of the electromechanical conversion element. However, such a drive device can reliably maintain the electrode terminal and the electromechanical conversion element in the connected state by the conductive member. For this reason, such a drive device can be made highly reliable.

  Since the conductive member is disposed at the contact portion between the electrode spring and the electrode portion of the electromechanical conversion element, such a drive device is provided with an electrode portion formed by the electrode spring accompanying vibration (extension / contraction) of the electromechanical conversion element. Can reduce wear.

  Since the conductive member is formed on the basis of a conductive paste or a conductive adhesive, for example, it is formed by applying and curing the conductive member, so that the conductive member can be easily disposed and manufactured easily. it can. There is a possibility that deposits may adhere to the electrode part of the electromechanical conversion element due to gas etc. generated when the adhesive that bonds the drive shaft and the electromechanical conversion element is hardened, but conduction failure may occur. Deposits are removed by the contact.

  For example, when the electrode spring is assembled, it is possible to secure better conduction by sliding the electrode spring on the electrode portion of the electromechanical transducer.

  In another aspect, in the above-described driving device, the conductive member is formed at a contact portion between the electrode terminal and the electrode spring so as to straddle the electrode terminal and the electrode spring.

  Such a driving device can reliably maintain the electrode terminal and the electrode spring in a connected state. Such a driving device can reduce the elastic force applied from the electrode spring to the electrode terminal, and can suppress creep caused by the elastic force of the electrode spring over time.

  In another aspect, in the above-described driving devices, the electromechanical conversion element is disposed on an outer peripheral side of the coil portion so as to be in contact with the electrode spring, and the electrode spring is disposed on the coil portion. An axial direction is disposed so as to be substantially parallel to the expansion / contraction direction of the electromechanical transducer.

  In such a driving device, the electromechanical conversion element can be disposed from the outer peripheral side of the coil portion in a state where the electrode spring is disposed, and the assembly can be easily performed. Further, such a driving device can be mechanically assembled, and continuous production is possible.

  In another aspect, the above-described driving device further includes a holding member that directly or indirectly holds the other end of the electromechanical conversion element, and the electrode terminal has a distance from the electromechanical conversion element. And a substantially protruding portion protruding from the holding member, the protruding portion being inserted into the coil portion.

  Such a driving device can easily connect the electrode terminal and the coil portion. Such a driving device can position and support the electrode spring by the protruding portion of the electrode terminal, and does not require a separate member for supporting the electrode spring, and can be easily manufactured.

  Such a drive device can handle, for example, an electrode spring and insert a protruding portion into the coil portion, and can also automate the process.

  In another aspect, in the above-described driving devices, the protruding portion is formed with a width larger than the inner diameter of the coil portion so as to be press-fitted into the coil portion.

  Such a drive device can reliably connect the coil portion and the protruding portion of the electrode terminal by press-fitting the protruding portion of the electrode terminal into the coil portion.

  In another aspect, in the above-described driving device, the electrode spring is a torsion coil spring having a first foot portion and a second foot portion respectively disposed at both axial end portions of the coil portion. The first leg part contacts the electrode part of the electromechanical transducer.

  In such a drive device, the contact between the electrode portion of the electromechanical conversion element and the electrode terminal can be further ensured, and the first foot portion in contact with the electrode portion of the electromechanical conversion element allows the electrode portion to It is possible to reliably remove the deposits attached to

  In another aspect, the above-described driving device further includes a holding member that directly or indirectly holds the electromechanical conversion element, and the electrode spring includes the first leg portion in the electromechanical conversion element. The second leg is disposed on one end side, and is disposed on the other end side of the electromechanical transducer.

  In such a drive device, since the second foot is disposed on the other end side opposite to the drive shaft in the electromechanical transducer, the second foot is driven by the electromechanical transducer. It is possible to make the shaft hardly interfere with the moving body moving along the axial direction. As a result, such a drive device can reduce the thickness of the entire device and can reduce the height of the entire device.

  In another aspect, in the above-described driving device, the second foot portion contacts the electrode terminal.

  Such a driving device can reliably bring the second foot into contact with the electrode terminal. Thereby, such a drive device can make contact | abutting of the electrode part of an electromechanical conversion element and an electrode terminal still more reliable via an electrode spring.

  In another aspect, in the above-described driving devices, the holding member has a substantially rectangular shape when viewed from one side of the driving shaft, and the electromechanical conversion elements have side surfaces facing each other and are opposed to each other. The side surface is disposed substantially parallel to the first corner portion of the holding member along a direction from the first corner portion of the holding member toward the center of the holding member, and the electrode portions face each other. Arranged on each of the side surfaces.

  An imaging apparatus according to another aspect includes any one of the above-described driving apparatuses, an imaging element that converts an optical image into an electrical signal, and one or a plurality of optical elements. An image pickup optical system that forms an image on a light receiving surface of the image pickup element, and an optical element that moves along an optical axis direction among the one or more optical elements in the image pickup optical system is Attached to a moving body.

  Since such an imaging device includes any one of the above-described driving devices, the electrode terminal and the electrode portion of the electromechanical conversion element can be reliably connected to each other, for example, even when receiving an impact due to dropping, the electrode spring Due to the elasticity, the electrode terminal and the electrode portion of the electromechanical conversion element can be connected to each other.

  In such an imaging apparatus, since the electrode spring is connected to each of the electrode terminal and the electrode portion of the electromechanical conversion element, an error in manufacturing dimensions of each portion can be absorbed and the contact state can be ensured.

  In addition, even if the electrode spring is not in contact with the electrode terminal or the electrode portion of the electromechanical conversion element, such an imaging device reliably connects the electrode terminal and the electromechanical conversion element by the conductive member. It can be maintained and made reliable.

  In such an imaging device, the conductive member is disposed so as to come into contact with each of the contact portions between the electrode spring and the electrode portion of the electromechanical conversion element, so that the electrode accompanying the vibration of the electromechanical conversion element Wear of the electrode portion due to the spring can be suppressed.

  This application is based on Japanese Patent Application No. 2012-231655 filed on October 19, 2012, the contents of which are included in the present application.

  In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. To be construed as inclusive.

  ADVANTAGE OF THE INVENTION According to this invention, the drive device used suitably for the imaging device which can be mounted, for example in a mobile telephone etc., and an imaging device using the same can be provided.

Claims (9)

An electromechanical transducer that converts electrical energy into expanding and contracting mechanical energy;
A drive shaft that is fixed to one end of the electromechanical transducer in the direction of expansion and contraction and that transmits the mechanical energy;
An electrode terminal for receiving electric power transmitted to the electromechanical transducer;
An electrode spring having a coil portion in contact with each of the electrode terminal and an electrode portion provided in the electromechanical transducer;
A conductive member formed on the basis of a conductive paste or a conductive adhesive so as to straddle the electrode spring and the electrode portion at a contact portion between the electrode spring and the electrode portion of the electromechanical transducer; ,
The electromechanical conversion element is disposed on the outer peripheral side of the coil portion so as to be in contact with the electrode spring ,
The electrode spring is disposed such that the axial direction of the coil portion is substantially parallel to the expansion / contraction direction of the electromechanical transducer .
Drive device. The conductive member is formed so as to straddle the electrode terminal and the electrode spring at a contact portion between the electrode terminal and the electrode spring.
The drive device according to claim 1. A holding member that directly or indirectly holds the other end of the electromechanical conversion element;
The electrode terminal includes a protrusion protruding from the holding member substantially parallel to the electromechanical conversion element at a distance,
The protruding portion is inserted into the coil portion.
The drive device according to claim 1 or 2 . The projecting portion is formed to have a width larger than the inner diameter of the coil portion so that it can be press-fitted into the coil portion.
The drive device according to claim 3 . The electrode spring is a torsion coil spring having a first foot portion and a second foot portion respectively disposed at both ends in the axial direction of the coil portion.
The first foot portion is in contact with an electrode portion of the electromechanical transducer;
The drive device according to any one of claims 1 to 4 . A holding member that directly or indirectly holds the electromechanical conversion element;
The electrode spring is disposed such that the first foot is located on the one end side of the electromechanical transducer and the second foot is located on the other end of the electromechanical transducer. ,
The drive device according to claim 5 . The second foot portion is in contact with the electrode terminal;
The driving device according to claim 5 or 6 . The holding member is substantially rectangular when viewed from one side of the drive shaft,
The electromechanical transducer has side surfaces facing each other,
The opposing side surfaces are disposed substantially parallel to the first corner portion of the holding member along a direction from the first corner portion of the holding member toward the center of the holding member,
The electrode portion is disposed on each of the opposing side surfaces,
The drive device according to any one of claims 1 to 7 . A driving device according to any one of claims 1 to 8 ,
An image sensor that converts an optical image into an electrical signal;
An imaging optical system that includes one or more optical elements, and that forms an optical image of an object on a light receiving surface of the imaging element;
The optical element that moves along the optical axis direction among the one or more optical elements in the imaging optical system is attached to the moving body of the driving device.
Imaging device.

Images