JP2014060885A - Drive device, and imaging device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive device and an imaging device, capable of reducing breakage of an electromechanical conversion element caused by stress generated by impact or the like by a relatively simple configuration even in the case that the electromechanical conversion element and a drive member are adhered and fixed to each other.SOLUTION: A drive device comprises: an electromechanical conversion element 11 converting an electric energy into a mechanical energy for expansion and contraction; a drive member 12 fixed to one end in an expansion and contraction direction, of the electromechanical conversion element 11, and to which the mechanical energy is transmitted; a base member 13 fixed to the another end in the expansion and contraction direction, of the electromechanical conversion element 11; a moving member 14 engaged with the drive member 12 by a predetermined friction force; a coating member 15 coating the fixed part between the electromechanical conversion element 11 and the drive member 12; and a coupling member 16 coupling between the coating member 15 and the base member 13 with each other.

Description

  The present invention relates to a drive device using an electromechanical transducer that converts electrical energy into mechanical energy, and an imaging device using the drive device.

  In a mechanical device including a movable part, an actuator is usually incorporated to drive the movable part. This actuator is a device that converts input energy into mechanical motion, one of which is called SIDM (Smooth Impact Drive Mechanism, “SIDM” is a registered trademark), for example, an electromechanical conversion such as a piezoelectric element. A driving device using an element is known.

  This SIDM drive device is typically an electromechanical conversion element that converts electrical energy into mechanical energy, a drive member that is fixed to one end of the electromechanical conversion element and that transmits the mechanical energy, and the drive member. A moving member and the like engaged with a predetermined friction force are provided. The electromechanical transducer is, for example, a piezoelectric element in which a plurality of piezoelectric layers made of a piezoelectric material are stacked via internal electrodes between each piezoelectric layer. A pair of external electrodes for supplying the electric energy is respectively formed on a pair of side surfaces facing each other along the stacking direction of the piezoelectric elements, and the pair of external electrodes is connected to the plurality of internal electrodes. They are connected alternately one after another. In such a SIDM drive device, when a sawtooth or pulsed drive voltage is applied from an external drive circuit via the pair of external electrodes, the piezoelectric element expands and contracts in the stacking direction. The drive member reciprocates in the longitudinal direction according to the expansion and contraction of the piezoelectric element. Here, when the electromechanical conversion element (here, the piezoelectric element) is repeatedly expanded and contracted so that the moving speed of the driving member is asymmetric between the forward path and the backward path, the moving member is moved by the asymmetric reciprocating motion of the driving member. Moving along the longitudinal direction, electrical energy is converted into movement of the moving member.

  In such a SIDM drive device, the electromechanical conversion element and the drive member are usually bonded and fixed by an adhesive such as an epoxy adhesive. Since the electromechanical conversion element expands and contracts, a compressive force and a tensile force are alternately applied to the bonded portion. For this reason, when a drive device is used for a long time, even if it is a minute vibration, an adhesion part may loosen and peel in a long time. Therefore, as such a countermeasure, for example, there is an SIDM driving device disclosed in Patent Document 1. The drive device disclosed in Patent Document 1 further includes a reinforcing member in which a coupling portion between the electromechanical conversion element and the drive member integrally covers the base portion of the electromechanical conversion element and the base portion of the drive member.

  On the other hand, such a SIDM drive device is usually formed long in the expansion / contraction direction of the piezoelectric element of the electromechanical transducer. For this reason, when an external force is applied from a direction orthogonal to the contraction direction of the piezoelectric element, the piezoelectric element is bent with respect to the drive shaft of the drive member, and the piezoelectric element may be damaged depending on the bent state. Therefore, as such a countermeasure, for example, there is an SIDM driving device disclosed in Patent Document 2. The driving device disclosed in Patent Document 2 is a first magnetic device that urges the driving shaft toward the piezoelectric element side by magnetic force and connects one end surface in the axial direction of the driving shaft to the other end surface in the expansion / contraction direction of the piezoelectric element. A first magnetic body and a second magnetic body, wherein the first magnetic body and the second magnetic body are spaced apart in the axial direction, and the first magnetic body and the second magnetic body One is fixed to the drive shaft, and the other is fixed to a fixing member. According to Patent Document 2, in such a configuration, the first magnetic body is attracted to the second magnetic body by a magnetic force, and one end surface of the drive shaft is connected in surface contact with the other end surface of the piezoelectric element. The piezoelectric element can be displaced in the direction in which the external force is applied to the drive shaft by an external force applied from a direction orthogonal to the axial direction. For this reason, the piezoelectric element is not bent with respect to the drive shaft, and damage to the piezoelectric element can be prevented.

JP-A-8-286093 JP 2011-69882 A

  By the way, since the SIDM drive device is formed long in the expansion / contraction direction of the electromechanical transducer as described above, it is relatively weak to bending stress when subjected to an impact or the like. In particular, in the SIDM drive device disclosed in Patent Document 1, since the coupling portion between the electromechanical conversion element and the drive member is covered by the reinforcing member, the next electromechanical conversion element that is vulnerable to stress is caused by the impact or the like. There was a risk of breakage due to the generated stress.

  Even if it is going to employ | adopt the method disclosed by patent document 2 as a countermeasure against this failure | damage of an electromechanical conversion element, the method disclosed by patent document 2 does not adhere and fix an electromechanical conversion element and a drive member 1st and Since the second magnetic body is coupled by the magnetic force of the second magnetic body, the technique disclosed in Patent Document 2 is such that the electromechanical conversion element and the driving member are bonded and fixed as in the SIDM driving apparatus disclosed in Patent Document 1. It cannot be applied to the existing SIDM drive unit.

  The present invention has been made in view of the above circumstances, and its purpose is to break an electromechanical conversion element due to stress caused by an impact or the like even when the electromechanical conversion element and a driving member are bonded and fixed. It is an object of the present invention to provide a driving device capable of reducing the above with a relatively simple configuration and an imaging device using the same.

  As a result of various studies, the present inventor has found that the above object is achieved by the present invention described below. That is, the drive device according to one aspect of the present invention is fixed to an electromechanical conversion element that converts electric energy into mechanical energy that expands and contracts, and one end of the electromechanical conversion element in the expansion and contraction direction, and transmits the mechanical energy. A driving member, a base member fixed to the other end of the electromechanical conversion element in the expansion / contraction direction, a moving member engaged with the driving member with a predetermined frictional force, the electromechanical conversion element, and the driving member And a connecting member that connects the covering member and the base member to each other. Preferably, the connecting member is a hollow columnar member having a lid portion having a through-opening at one end, the covering member is fitted into the through-opening, and the other end of the hollow columnar member is By fixing to the base member, the covering member and the base member are connected to each other.

  Such a driving device has a relatively simple structure in which the covering member and the base member are connected to each other by the connecting member, and even when the electromechanical conversion element and the driving member are bonded and fixed, the stress generated by an impact or the like. Is received not only by the electromechanical conversion element but also by the connecting member, so that the breakage of the electromechanical conversion element due to the stress can be reduced.

  According to another aspect, in the above drive device, the hollow columnar member further includes a protruding portion in which a part of a peripheral surface (side surface) protrudes radially outward over the entire periphery. To do.

  In such a drive device, since a part of the peripheral surface of the hollow columnar member is a protruding portion, the spring constant as the elastic body in the connecting member is adjusted in the expansion / contraction direction of the electromechanical conversion element, and in the connecting member The spring constant as the elastic body is smaller than the spring constant as the elastic body in the electromechanical conversion element in the expansion and contraction direction of the electromechanical conversion element. For this reason, such a drive apparatus can reduce the obstruction | occlusion of the displacement of the expansion / contraction direction in an electromechanical conversion element by a connection member.

  According to another aspect, in the above-described driving device, the connecting member is formed integrally with the covering member.

  In such a drive device, since the connecting member and the covering member are integrally formed, the number of assembling steps can be reduced and the assembly can be performed more easily.

  An imaging apparatus according to another embodiment of the present invention includes any one of the above-described driving apparatuses, an imaging element that converts an optical image into an electrical signal, and one or more optical elements. An imaging optical system that forms an optical image of an object on a light receiving surface of the imaging element, and an optical element that moves along an optical axis direction among the one or more optical elements in the imaging optical system is It is attached to the moving member of the drive device.

  Since such an imaging apparatus includes any one of the above-described driving devices, even when the electromechanical conversion element and the driving member are bonded and fixed, the electromechanical conversion element caused by stress caused by an impact or the like is used. Breakage can be reduced with a relatively simple configuration. Therefore, such an imaging apparatus can improve impact resistance.

  The drive device and the imaging device according to the present invention reduce the breakage of the electromechanical conversion element due to stress caused by an impact or the like with a relatively simple configuration even when the electromechanical conversion element and the drive member are bonded and fixed. Can do.

It is sectional drawing which shows the structure of the imaging device using the drive device concerning embodiment. It is a perspective view which shows the structure of the drive device used for the imaging device shown in FIG. It is a perspective view which shows the structure of the connection member of the 1st aspect used for the drive device shown in FIG. It is a figure for demonstrating the drive pulse supplied to the drive device used for the imaging device shown in FIG. It is a perspective view which shows the structure of the connection member of a 2nd aspect. It is sectional drawing which shows the structure of the connection member of a 3rd aspect.

  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.

  FIG. 1 is a cross-sectional view illustrating a configuration of an imaging apparatus using a driving device according to the embodiment. FIG. 2 is a perspective view illustrating a configuration of a driving device used in the imaging apparatus illustrated in FIG. 2A is a partially exploded perspective view, and FIG. 2B is an overall external perspective view. FIG. 3 is a perspective view showing the configuration of the connecting member of the first aspect used in the drive device shown in FIG. FIG. 4 is a diagram for explaining drive pulses supplied to a drive device used in the imaging apparatus shown in FIG. The horizontal axis in FIG. 4 is time, and the vertical axis is voltage.

  The imaging device IM in the embodiment includes an electromechanical conversion element 11, a driving member 12, a base member 13, a moving member 14, a covering member 15, a connecting member 16, a pad 17, a spring 18, and a driving circuit. 20, an image sensor 30, and a housing 40 (41, 42, 43) that accommodates these and not shown in its entirety. In such an imaging apparatus IM, the driving device includes the electromechanical conversion element 11, the driving member 12, the base member 13, the moving member 14, the covering member 15, the connecting member 16, the pad 17, and the spring 18. And is configured.

The electromechanical transducer 11 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. Such a piezoelectric element 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. Each of the plurality of internal electrode layers is configured to face the outside with a pair of outer peripheral side surfaces facing each other. The pair of external electrodes are formed along the stacking direction on the pair of outer peripheral side surfaces in the stacked body, and supply the electric energy to the stacked body, and are sequentially and alternately connected to the plurality of internal electrodes. . Examples of the piezoelectric material include so-called PZT, crystal, lithium niobate (LiNbO ₃ ), potassium niobate tantalate (K (Ta, Nb) O ₃ ), barium titanate (BaTiO ₃ ), lithium tantalate (LiTaO ₃ ). And inorganic piezoelectric materials such as strontium titanate (SrTiO ₃ ).

  The drive member 12 is fixed to an end surface of one end in the expansion / contraction direction of the electromechanical conversion element (piezoelectric element in the present embodiment) 11, and a member to which mechanical energy converted from electric energy is transmitted by the electromechanical conversion element 11 is transmitted. It is. More specifically, in this embodiment, the drive member 12 is a columnar (axial) member fixed to one end face of the laminate in the piezoelectric element. The drive member 12 is supported by a pair of support members 41 and 42 extended from a casing 40 (not shown) so as to be movable in parallel with the axial direction a. The pair of support members 41, 42 are arranged at a predetermined interval, and define a moving range of the moving member 14 that frictionally engages the drive member 12 between the pair of support members 41, 42. Yes. As the material of the drive member 12, for example, any material such as metal, resin, and carbon can be used. The cross section orthogonal to the longitudinal direction of the drive member 12 may be any shape such as a rectangle, a polygon, an ellipse, and a circle, but in the present embodiment, the moving member 14 extends along the longitudinal direction of the drive member 12. The cross section is circular so that it can be moved relatively easily. In addition, when this cross section is a rectangle or a polygon, it is preferable that it is chamfered from the said viewpoint.

  The base member 13 is a member fixed to the end surface of the other end of the electromechanical conversion element 11 in the expansion / contraction direction. More specifically, the base member 13 has a cylindrical shape having a diameter that matches the outer shape of the electromechanical conversion element 11, and supports the electromechanical conversion element 11 by being fixed to the electromechanical conversion element 11. doing. The base member 13 is fixed to the main body member 43 of the casing 40 on the surface where the electromechanical conversion element 11 is not fixed. As described above, the base member 13 is fixed to the main body member 43 of the housing 40, so that the base member 13 is stationary with respect to the expansion and contraction motion of the electromechanical conversion element 11. Then, it is transmitted to the drive member 12. The main body member 43 itself of the housing 40 may be the base member 13. In this case, the electromechanical conversion element 11 is directly connected to the main body of the housing 40 at the other end face in the expansion / contraction direction. It is fixed to the member 43. In short, the electromechanical conversion element 11 may be fixed to a member larger than the inertial mass of the drive member 12 in order to mainly transmit the expansion and contraction motion to the drive member 12.

  The moving member 14 is a member that is engaged with the driving member 12 with a predetermined frictional force, and slides with respect to the driving member 12. In the present embodiment, the moving member 14 is a lens holding frame that supports and holds a lens L1, which is an example of an optical element.

  A slider block 141 is formed on the moving member 14 of the lens holding frame by extending a part of the outer periphery. A through opening is formed in the slider block 141 along the direction of the optical axis AX, and the drive member 12 is inserted through the through opening. The direction of the optical axis AX and the axial direction a are parallel. Further, a notch 142 is formed at the center of the slider block 141, and the radial half of the drive member 12 is exposed at the notch 142. A pad 17 that contacts the half of the driving member 12 in the radial direction is fitted into the notch 142, and a biasing force in the direction toward the driving member 12 is applied to the pad 17 by a spring 18. . With such a structure, the moving member 14 including the pad 17 and the driving member 12 are pressed against each other by the urging force of the spring 18 and frictionally engaged with each other with a predetermined frictional force. The structure that frictionally engages the moving member 14 and the driving member 12 is not limited to such a structure.

  The covering member 15 is a member that covers a fixed portion between the electromechanical conversion element 11 and the driving member 12. More specifically, the covering member 15 covers the base portion of the electromechanical conversion element 11 in the vicinity of the fixed portion, and has a first hollow short columnar portion having an inner shape corresponding to the outer shape of the electromechanical conversion element 11. 151, a second hollow short columnar portion 152 having an inner shape corresponding to the outer shape of the driving member 12 covering the base of the driving member 12 in the vicinity of the fixed portion, and one of the first hollow short columnar portions An annular connecting portion 153 that connects the end portion and the other end portion of the second hollow short columnar portion is provided. In the example shown in FIGS. 1 and 2, the first hollow short high columnar portion 151 is a hollow short high columnar member, the second hollow short high columnar portion 152 is a short high tubular member, and has an annular shape. The connecting portion 153 is an annular plate member having a circular opening having a diameter corresponding to the outer diameter of the second hollow short high columnar portion 152, and has an outer shape having a size corresponding to the outer shape of the first hollow short high columnar portion 151. An annular plate member that is a quadrangle. The covering member 15 is formed of a material such as metal or resin, for example. In such a covering member 15, after the driving member 12 and the base member 13 are bonded and fixed to the electromechanical conversion element 11, the second hollow short high columnar portion 152 starts from the other end of the first hollow short high columnar portion 151. The drive member 12 is inserted into the first member, and the inside of the drive member 12 is filled with an adhesive, and the base portion of the electromechanical conversion element 11 is fitted into the first hollow short columnar portion 151. As a result, the electromechanical conversion element 11, the drive member 12, and the covering member 15 are integrally bonded and fixed so as to cover the fixed portion between the electromechanical conversion element 11 and the drive member 12.

  The connecting member 16 is a member for connecting the covering member 15 and the base member 13 to each other. For example, a hollow columnar member having a lid portion having a through opening having a size corresponding to the outer shape of the covering member 15 at one end. It is. When the main body member 43 itself of the housing 40 is the base member 13, the connecting member 16 is connected to the main body member 43 of the housing 40. More specifically, for example, as shown in FIGS. 1 to 3, the connecting member 16 has a cylindrical shape having a lid portion 162 having a through-opening 163 having a diameter corresponding to the outer shape of the covering member 15 at one end. This is a cylindrical member 161. The connecting member 16 is formed of a material such as metal or resin, for example. The inner diameter of the cylindrical member 161 is at least larger than the size of the electromechanical transducer 11. More specifically, the inner diameter of the cylindrical member 161 is longer than at least the diagonal length of the electromechanical transducer 11 because the electromechanical transducer 11 has a prismatic shape. In the present embodiment, the inner diameter of the cylindrical member 161 is a length corresponding to the outer shape of the base member 13 so that one end of the base member 13 fits into the cylindrical member 161, that is, the outer diameter of the base member 13. It is almost the same. In the example shown in FIGS. 1 to 3, in order to draw out a pair of wires connected to the pair of external electrodes of the electromechanical transducer 11 to the outside, a predetermined length in the axial direction and a predetermined length in the circumferential direction. A slit-shaped notch 164 formed with a width is formed on the peripheral surface of the other end of the cylindrical member 161. The number of notches 164 may be one, but preferably two to facilitate the insulation of the pair of wires, and the pair of wires are connected when the connecting member 16 is mounted as described later. More preferably, the number of the electromechanical transducer elements 11 and the connecting member 16 is three or more so that the relative arrangement relationship between the electromechanical transducer 11 and the connecting member 16 can be ignored as much as possible. In the example shown in FIG. 3, there are four notches 164. In such a connecting member 16, after the covering member 15 is bonded and fixed as described above, the driving member 12 is inserted from the other end of the cylindrical member 161, and the inside is filled with an adhesive, and the lid portion One end of the second hollow short columnar portion of the covering member 15 is fitted into the through-opening 163 of 162, and an adhesive is filled inside the one end of the base member 13 at the other end of the cylindrical member 161. It is inserted. In this way, the covering member 15 is fitted into the through-opening 163 and bonded and fixed, and the other end of the cylindrical member 161 is bonded and fixed to the base member 13, whereby the connecting member 16 is connected to the covering member 15 and the base member 13. Are connected to each other. For example, an epoxy-based adhesive or a cyanoacrylate-based adhesive is used as the adhesive for fixing each of the above-described adhesives.

  The drive circuit 20 is a circuit that generates a predetermined drive pulse supplied to the electromechanical conversion element 11 in order to drive the electromechanical conversion element 11. As the drive circuit 20, for example, a known oscillation circuit that oscillates a sawtooth drive pulse shown in FIG. 4 can be used. When the frequency of the sawtooth drive pulse is about 20 to 30 kHz, the vibration frequency is out of the audible range, and the vibration sound that can be heard by the human ear can be reduced. However, the frequency may be any frequency. When the drive pulse of the sawtooth wave shown in FIG. 4 is supplied from the drive circuit 20 to the electromechanical conversion element 11, the electromechanical conversion element 11 becomes loose at the gentle rising portion of the drive pulse of the sawtooth wave. The drive member 12 that is extended and displaced in the expansion / contraction direction and is bonded and fixed to the electromechanical conversion element 11 is also gradually displaced in the axial direction a. In this case, the slider block 141 of the moving member 14 that is frictionally engaged with the driving member 12 moves in the axial direction a together with the driving member 12 by the frictional force. At the rapid falling portion of the sawtooth drive pulse, the electromechanical transducer 11 is rapidly contracted and displaced in the expansion / contraction direction, and the drive member 12 is also displaced in the direction opposite to the axial direction a. In this case, the slider block 141 of the moving member 14 overcomes the frictional force by the inertial force, stays at that position, and does not substantially move. By repeating this continuously, the slider block 141 of the moving member 14 moves in the axial direction a. Then, by reversing the waveform of the sawtooth driving pulse and supplying the electromechanical transducer 11 with a sawtooth driving pulse composed of a rapid rising portion and a subsequent gentle falling portion, the moving member Fourteen slider blocks 141 move in the opposite direction.

  Further, for example, the driving circuit 20 includes an H bridge circuit including four known switching elements that oscillate with a rectangular pulse having a predetermined duty ratio (for example, 3: 7 or 7: 3) as a driving pulse, or two switching elements. A half-bridge circuit with elements can be used. The predetermined duty ratio is, for example, 3: 7 or 7: 3, and the traveling direction of the moving member 14 can be reversed by reversing the duty ratio in this way.

  The image sensor 30 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 30 is, for example, a CCD image sensor, a CMOS image sensor, or the like.

  The imaging optical system includes one or more optical elements, and forms an optical image of an object on the light receiving surface of the imaging element 30. The above-described lens L1 attached to the moving member 14 of the lens holding frame is an optical element that moves along the optical axis AX among the one or more optical elements in the imaging optical system. The lens L1 may be a single lens or a lens group including a plurality of lenses. The lens L1 may be, for example, a lens that moves along the optical axis AX to perform focusing (focusing), and, for example, a lens that moves along the optical axis AX to perform zooming (magnification). It may be. An optical image of the object is guided by the imaging optical system including the lens L1 to the light receiving surface of the imaging element 30 along the optical axis AX, and the optical image of the object is captured by the imaging element 30. The

  Such an imaging device IM and driving device have a relatively simple configuration in which the covering member 15 and the base member 13 are directly connected to each other by the connecting member 16, so that the electromechanical transducer 11 and the driving member 12 are bonded. Even when the electromechanical conversion element 11 is fixed, the electromechanical conversion element 11 can be reinforced so that stress such as bending stress caused by impact or the like can be received not only by the electromechanical conversion element 11 but also by the connecting member 16. It is possible to relieve the stress applied to the electromechanical transducer 11 and to reduce damage to the electromechanical transducer 11 due to the stress.

  Next, the deformation | transformation form of a connection member is demonstrated.

  FIG. 5 is a perspective view showing the configuration of the connecting member of the second aspect. FIG. 6 is a cross-sectional view showing the configuration of the connecting member of the third aspect.

  In the imaging device IM and the driving device in the above-described embodiment, the connecting member 16 illustrated in FIGS. 1 to 3 is used. However, the aspect of the connecting member 16 is not limited to this, and the connecting member of another aspect is used. May be used.

  For example, instead of the connecting member 16, a connecting member 51 of the second mode shown in FIG. 5 may be used. The connecting member 51 is a hollow columnar member having a lid portion having a through opening having a size corresponding to the outer shape of the covering member 15 at one end, and a part of the peripheral surface (side surface) of the hollow columnar member is A projecting portion projecting radially outward is provided over the entire circumference. More specifically, as shown in FIG. 5, the connecting member 51 is a cylindrical cylindrical member 511 having a lid portion 512 having a through opening 513 having a diameter corresponding to the outer shape of the covering member 15 at one end. In addition, a part of the peripheral surface of the cylindrical member 511 is provided with a protruding portion 515 that protrudes radially outward over the entire periphery. That is, in the protruding portion 515, the cross-sectional shape of the peripheral surface (side surface) of the connecting member 51 has a wave shape. Similarly to the connection member 16 of the first aspect, a slit-shaped notch 514 is formed on the peripheral surface of the other end of the cylindrical member 511 in order to draw the wiring to the outside.

  In such a connecting member 51, since a part of the peripheral surface of the cylindrical member 511 is a protruding portion 515, the spring constant as an elastic body in the connecting member 51 is adjusted in the expansion / contraction direction of the electromechanical transducer 11. The spring constant as the elastic body in the connecting member 51 is smaller than the spring constant as the elastic body in the electromechanical conversion element 11 in the expansion / contraction direction of the electromechanical conversion element 11. For this reason, the drive device and the imaging device IM using such a connection member 51 can reduce the inhibition of the displacement in the expansion / contraction direction in the electromechanical transducer 11 by the connection member 51. In addition, the magnitude | size (value) of the spring constant of the connection member 51 can be suitably adjusted with the number of the protrusion parts 515, and in the example shown in FIG. 5, the protrusion parts 515 are predetermined intervals along an axial direction. And a plurality of, specifically, two projecting portions 515-1 and 515-2 juxtaposed in parallel.

  Further, for example, instead of the connecting member 16, a connecting member 61 of the third aspect shown in FIG. 6 may be used. The connecting member 61 is formed integrally with the covering member. More specifically, as shown in FIG. 6, the connecting member 61 is a cylindrical member 611 having a lid 612 having a through opening having a diameter corresponding to the outer shape of the driving member 12 at one end. The base of the electromechanical conversion element 11 in the vicinity of the fixed portion is covered on the inner side of the lid 612 so as to extend from the inner surface of the lid 612 in the vicinity of the periphery of the through opening and to stand substantially vertically. A first hollow short columnar portion 613 having an inner shape corresponding to the outer shape of the electromechanical conversion element 11 is formed, and is extended substantially from the periphery of the through-opening on the outside of the lid portion 612. A second hollow short columnar portion 614 having an inner shape corresponding to the outer shape of the driving member 12 that covers the base of the driving member 12 in the vicinity of the fixed portion is formed so as to stand upright. The first and second hollow short columnar portions 613 and 614 are the same as the first and second hollow short columnar portions 151 and 152 described above.

  Since such a connecting member 61 is formed integrally with the covering member, it is possible to reduce the number of assembling steps and to assemble more easily.

  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.

IM driving device L1 lens 11 electromechanical conversion element 12 driving member 13 base member 14 moving member 15 covering member 16, 51, 61 connecting member 20 driving circuit 30 imaging element 161, 511, 611 cylindrical member 162, 512, 612 lid 163 513 Through opening

Claims (5)

An electromechanical transducer that converts electrical energy into elastic mechanical energy;
A driving member that is fixed to one end of the electromechanical transducer in the direction of expansion and contraction and that transmits the mechanical energy;
A base member fixed to the other end in the expansion / contraction direction of the electromechanical transducer;
A moving member engaged with the driving member with a predetermined frictional force;
A covering member that covers a fixed portion of the electromechanical transducer and the drive member;
A drive device comprising: a connecting member that connects the covering member and the base member to each other. The connecting member is a hollow columnar member having a lid portion having a through-opening at one end, and the covering member is fitted into the through-opening and the other end of the hollow columnar member is fixed to the base member. The drive device according to claim 1, wherein the covering member and the base member are connected to each other. The drive device according to claim 2, wherein the hollow columnar member further includes a protruding portion in which a part of the peripheral surface protrudes radially outward over the entire circumference. The drive device according to claim 1, wherein the connecting member is formed integrally with the covering member. The drive device according to any one of claims 1 to 4,
An image sensor that converts an optical image into an electrical signal;
An imaging optical system that includes one or a plurality of optical elements, and that forms an optical image of an object on a light receiving surface of the imaging element;
An imaging device, wherein an optical element that moves along an optical axis direction among the one or more optical elements in the imaging optical system is attached to the moving member of the driving device.

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