JP4736468B2 - Piezoelectric actuators and equipment - Google Patents

Description

  The present invention relates to a piezoelectric actuator that drives a driven body by vibration of a piezoelectric element, and an apparatus including the piezoelectric actuator.

  Conventionally, as a piezoelectric actuator that drives a driven body by vibration of a piezoelectric element, a structure in which plate-like piezoelectric elements are bonded to both surfaces of a reinforcing plate has been developed (see, for example, Patent Document 1). In this piezoelectric actuator, in order to excite a predetermined vibration mode in the piezoelectric element, the electrode on the front surface (front side) is divided into a plurality of parts, and the electrode on the back side is connected to the reinforcing plate, thereby conducting to the reinforcing plate. is doing. The plurality of electrodes on the front side are connected to each other by an overhang portion from the substrate. At this time, since the piezoelectric elements are provided on both surfaces of the reinforcing plate, in order to make the corresponding electrodes among the electrodes on the front side of the piezoelectric elements conductive, in this piezoelectric actuator, one substrate is folded and both ends of the substrate are folded. An overhang portion is formed from the surface toward the surface of each piezoelectric element. With such a conductive structure, when a predetermined voltage is applied between the electrode on the surface of the piezoelectric element and the reinforcing plate, the piezoelectric element expands and contracts to excite vibration, and the driven body is driven by this vibration.

JP 2004-289965 A (FIG. 3)

However, in the piezoelectric actuator having such a configuration, since a plurality of electrodes are formed on the surface of the piezoelectric element, the substrate and the overhang part are piezoelectrically connected so that the overhang part is not connected to other electrodes on the surface of the piezoelectric element. It is necessary to dispose a predetermined distance from the element surface. For this reason, there exists a problem that the dimension of the thickness direction of the whole piezoelectric actuator will become large. At this time, the substrate must be bent to connect the overhang portions to the piezoelectric elements on both sides, and therefore the substrate must be arranged separately from the surface of the piezoelectric elements on both sides by a predetermined distance. It gets even bigger. In particular, the piezoelectric actuator is small and thin, and a relatively large driving force can be obtained. Therefore, application to a small device is desired. Therefore, downsizing and thinning of the piezoelectric actuator are important issues.
Further, in the piezoelectric actuator having such a structure, since a single substrate is folded and the overhang portion is joined to the electrodes of the piezoelectric elements on both sides, a predetermined distance is maintained between the substrate and the piezoelectric elements. Work such as joining the overhang part to both sides is required, and the assembly work becomes complicated.

  An object of the present invention is to provide a piezoelectric actuator that can be easily manufactured and can promote a reduction in thickness, and a device including the piezoelectric actuator.

The piezoelectric actuator of the present invention includes a rectangular piezoelectric element front electrode and the back electrode are formed, a reinforcing plate of the piezoelectric element and substantially the same shape that the piezoelectric element is insulated from the piezoelectric element while being located on both sides A lead substrate on which a conduction pattern for applying a voltage to the piezoelectric element is formed, and an overhang portion for conducting the back side electrode and a conduction pattern for the back side electrode of the lead substrate . wherein said rear electrode surface in contact with the reinforcing plate is formed with a plurality, wherein the back side electrode is the front electrode on the opposite side are formed, the reinforcing plate, the arm portion is integrally protruding in the width direction A recess is formed by cutting out a part of the long side of the reinforcing plate so that the opposing back-side electrodes of the both surfaces face each other, and the lead substrate is disposed on the arm portion, The space formed by the rear electrode and the recess, the conductive material is filled, through the conductive material and the overhang portion and the back side electrode, characterized in that the electrically conductive.

According to the present invention, since the back side electrode facing the reinforcing plate and the reinforcing plate in the piezoelectric element are insulated, even if a plurality of back side electrodes are formed, each electrode does not conduct with the reinforcing plate. Therefore, when each electrode is appropriately selected and a voltage is applied between the front side electrode and the back side electrode, only the piezoelectric element of the selected electrode portion vibrates, and the electrode shape and the combination of electrodes to which the voltage is applied vary. Vibration is excited. Therefore, the types of vibrations of the piezoelectric actuator are diversified, and it is possible to flexibly adjust the vibrations according to the driving conditions of the driven body.
Is formed with a plurality of electrodes on the back electrode, between the back electrode is made conductive by a conductive material to be charged in the recess formed in the reinforcing plate, it is electrically connected to the overhang portion via a conductive material Runode, on the front side There is no need to arrange a plurality of conductive portions. Therefore, when providing a substrate or the like, it is not necessary to dispose the substrate at a predetermined distance in the thickness direction from the surface of the piezoelectric element, so that the piezoelectric actuator can be made thinner.
In addition, since the concave portion is formed in the reinforcing plate, the conductive portion that is filled in the concave portion and conducts between the back-side electrodes does not protrude from the side surface of the piezoelectric element, so that the conducting portion is protected. Therefore, the reliability of conduction between the backside electrodes is improved. Further, since the concave portion is formed in the reinforcing plate, most of the portions other than the concave portion can come into contact with the piezoelectric element to reinforce the piezoelectric element, so that the strength and durability of the piezoelectric actuator can be ensured satisfactorily.

In addition, since a plurality of electrodes are formed as back side electrodes and these back side electrodes are electrically connected to each other by the conductive material filled in the recesses, unlike the conventional case, one substrate is bent and the corresponding electrodes There is no need to conduct from both sides. Therefore, it becomes possible to conduct the back side electrodes on both sides of the reinforcing plate with a single substrate. This also facilitates the thinning of the piezoelectric actuator, simplifies the conduction work, and facilitates the manufacture of the piezoelectric actuator. become.

In the present invention, the reinforcing plate is made of a conductive material, and an insulating layer is formed on a surface of the reinforcing plate that contacts the back side electrode and a surface that contacts the conductive material filled in the recess, and the front side electrode Is preferably conducted to the reinforcing plate, and the reinforcing plate is conducted to the conductive pattern for the front electrode of the lead substrate .
According to this invention, since the back side electrode is insulated from the reinforcing plate and the front side electrode is conducted to the reinforcing plate, if the conduction pattern for the front side electrode of the lead substrate is conducted to the reinforcing plate, Conduction is achieved. Accordingly, since it is not necessary to stack a substrate or the like in the thickness direction of the piezoelectric element, the piezoelectric actuator can be further reduced in thickness.
Since the reinforcing plate is made of a conductive material, it is possible to use the reinforcing plate as a conductive terminal to the piezoelectric element, for example, by connecting the conductive pattern to the reinforcing plate, thus simplifying the structure of the piezoelectric actuator To do. In particular, when the front electrode is electrically connected to the reinforcing plate, the reinforcing plate itself is made of a conductive material, so that the conductive structure and the conductive operation are simplified.

In the present invention, the reinforcing plate is made of a non-conductive material, the front electrode is electrically connected to a conductive portion formed on an arm portion of the reinforcing plate, and the conductive portion is a conductive material for the front electrode of the lead substrate. It is desirable to conduct to the pattern .
According to this invention, since the reinforcing plate is made of a non-conductive material, the piezoelectric element and the reinforcing plate are not electrically connected. Therefore, since it is not necessary to form an insulating layer on the reinforcing plate surface, the manufacturing process of the piezoelectric actuator is simplified.

In the present invention, it is desirable that the concave portion is disposed near the vibration node of the piezoelectric actuator.
According to the present invention, when the concave portion is formed on the reinforcing plate, the concave portion is arranged near the vibration node of the piezoelectric actuator, so the back-side electrode conducting portion formed of the conductive material filled in the concave portion. Is also arranged near the vibration node of the piezoelectric actuator. Therefore, since the inhibition of the vibration of the piezoelectric actuator by the back side electrode conducting portion is suppressed to the minimum, the vibration efficiency of the piezoelectric actuator is improved. In addition, since the back-side electrode conducting portion is disposed in the vicinity of the vibration node of the piezoelectric actuator, occurrence of problems such as disconnection is prevented, and the reliability of joining between the back-side electrode conducting portion and the back-side electrode of the piezoelectric element is improved.

Here, the vibration node of the piezoelectric actuator means a position where the amplitude of the vibration of the piezoelectric actuator is minimized. For example, when the piezoelectric actuator excites only the longitudinal vibration that expands and contracts in the longitudinal direction, the vibration amplitude is 0. Means a position.
Also, the vicinity of the vibration node of the piezoelectric actuator means the vicinity of the vibration node of the piezoelectric actuator. For example, the vibration is greater than the midpoint of the line connecting the vibration node of the piezoelectric actuator and the antinode (position where the vibration amplitude is maximum). The position near the node.

A device according to the present invention includes the piezoelectric actuator described above.
According to the present invention, since the device includes the piezoelectric actuator described above, the same effects as those of the piezoelectric actuator described above can be obtained. In other words, the manufacture of the piezoelectric actuator is simplified and the thinning is promoted, so that the manufacture of the device is simplified, and the thinning and miniaturization of the device are promoted.

  According to the piezoelectric actuator and device of the present invention, since the back side electrode and the reinforcing plate are insulated and a plurality of back side electrodes are formed, it is not necessary to arrange a substrate or the like on the front side electrode of the piezoelectric element with a predetermined interval. Therefore, the piezoelectric actuator and device can be reduced in thickness and size. In addition, since the back-side electrode conducting part conducts the plurality of back-side electrodes, complicated conducting work such as folding the substrate or the like and conducting the electrodes of the piezoelectric elements on both sides of the reinforcing plate becomes unnecessary, and the manufacture of piezoelectric actuators and equipment Can be simplified.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the second embodiment and later described below, the same reference numerals are given to the same components and components having the same functions as those in the first embodiment described below, and description thereof will be simplified or omitted.

[First embodiment]
Hereinafter, the lens unit 10 as an apparatus according to the first embodiment of the present invention will be described. The lens unit 10 is mounted on a camera as a device, or is manufactured and used integrally with the camera.
In addition to the lens unit 10, the camera includes a recording medium that records an image formed by the lenses 30, 40, and 50 that constitute the lens unit 10, and a drive unit that drives the lenses 30, 40, and 50. And a case in which all of them are stored. However, illustration of a camera, a storage medium, and a case is omitted.
FIG. 1 is a perspective view of the lens unit 10 as viewed from the upper right, and FIG. 2 is a perspective view of the lens unit 10 as viewed from the upper left. 3A and 3B are operation diagrams of the cam member 60, and FIGS. 4A and 4B are operation diagrams of the cam member 70. FIG. 5 is an enlarged perspective view of the vibrating body 66 that drives the cam member 60.

  1 to 5, the lens unit 10 includes a generally rectangular housing 20, a first lens 30 as a driven body, a second lens 40, a third lens 50, a second lens 40, The cam member 60 that drives the third lens 50 to advance and retreat, the cam member 70 that drives the first lens 30 to advance and retract, the vibrating body 66 as a piezoelectric actuator that drives the cam member 60 to rotate, and the cam member 70 to rotate. And a vibrating body 76 as a driving piezoelectric actuator. Of these, the cam members 60 and 70 and the vibrating bodies 66 and 76 constitute the driving device 1 for driving the lenses 30, 40 and 50. Below, each structure is described concretely.

The casing 20 is provided with two rod-shaped guide shafts 21 in parallel from the front to the back. The guide shaft 21 is a member that guides the lenses 30, 40, and 50 to be advanced and retracted, and penetrates the lenses 30, 40, and 50 in the advance / retreat direction (optical axis direction). The guide shaft 21 plays a role of preventing the lenses 30, 40, 50 from falling back and forth.
Further, the side portions 22 on both sides of the housing 20 are provided with long hole-shaped openings 23A, 23B, and 23C, and these openings 23A, 23B, and 23C are provided in the lenses 30, 40, and 50, respectively. The cam bars 31, 41, 51 are formed in a size that can move sufficiently.

  The first lens 30 includes a cam bar 31 that is disposed inside the housing 20 and is located in the opening 23 </ b> C of the housing 20. The second lens 40 is provided inside the housing 20 and at the same time includes a cam bar 41 located in the opening 23 </ b> B of the housing 20. Similarly, the third lens 50 is disposed inside the housing 20 and at the same time includes a cam bar 51 positioned in the opening 23 </ b> A of the housing 20.

  These first to third lenses 30, 40, 50 include a central condensing part 32, 42, a condensing part of the third lens 50 (not shown) and surrounding frame attaching parts 33, 43, and a first not shown. The frame mounting portions of the three lenses 50 are integrally formed of a lens material, and are provided with holding frames 34, 44, and 54 for holding them. The holding frames 34, 44, 54 are provided with the cam bars 31, 41, 51 described above.

  The first lens 30 is a focus lens, and the second lens 40 and the third lens 50 are zoom lenses. The third lens 50 is not limited to a zoom lens, and may be a focus lens. In this case, the lens unit 10 can be used as a focus lens unit by appropriately setting the configuration of each lens 30, 40, 50 and the optical characteristics of each lens 30, 40, 50.

And although the 2nd lens 40 becomes a structure which combined the concave lens and the convex lens, the structure of each lens 30,40,50 etc. may be arbitrarily determined in consideration of the objective.
Further, in the present embodiment, the lenses 30, 40, 50 include the light collecting portions 32, 42, the light collecting portion of the third lens 50, the frame attaching portions 33, 43, and the frame attaching portion of the third lens 50. Although the lens material is integrally formed, only the light collecting portions 32 and 42 and the light collecting portion of the third lens 50 are formed of the lens material, and the frame attaching portions 33 and 43 and the third lens 50 are attached to the frame. The part side may be formed integrally with the holding frames 34, 44, 54 using a different material. Further, the condensing portions 32 and 42, the condensing portion of the third lens 50, the frame attaching portions 33 and 43, the frame attaching portion of the third lens 50, and the holding frames 34, 44, and 54 are formed of an integral lens material. May be

  The cam members 60 and 70 are installed between the outer surface portions 25A and 25B on both sides of the housing 20 and the cover member 10A fixed to the outside of the outer surface portions 25A and 25B by three feet 26, respectively. ing.

  The cam member 60 has a substantially fan shape having a rotation shaft 61, and is supported on the outer surface portion 25 </ b> A of the housing 20 so as to be rotatable about the rotation shaft 61. Further, two cam grooves 62A and 62B as drive guide portions are formed in the planar portion of the cam member 60. The cam grooves 62A and 62B are formed in a substantially arc shape, and the cam rod 41 of the second lens 40 is engaged with the cam groove 62B, and the cam rod 51 of the third lens 50 is engaged with the cam groove 62A. Accordingly, when the cam member 60 rotates, the cam rods 51 and 41 are guided to the cam grooves 62A and 62B, and move within a speed and a moving range according to the shapes of the cam grooves 62A and 62B. The second lens 40 advances and retreats.

  The cam member 70 has a substantially lever-like shape having a rotation shaft 71, and is supported on the outer surface portion 25 </ b> B of the housing 20 so as to be rotatable about the rotation shaft 71. Further, one cam groove 62 </ b> C as a driving guide portion is formed in the planar portion of the cam member 70. The cam groove 62C is formed in a substantially arc shape. When the cam rod 31 of the first lens 30 is engaged with the cam groove 62C, and the cam member 60 is thereby rotated, the cam rod 31 is moved to the cam groove 62C. The first lens 30 advances and retreats by moving at a speed and a moving range according to the shape of the cam groove 62C.

In these cam members 60, 70, vibrating bodies 66, 76 that vibrate in a plane substantially orthogonal to the rotation shafts 61, 71 are in contact with the outer peripheral surfaces of the rotation shafts 61, 71. At this time, the contact direction of the vibrating bodies 66 and 76 with respect to the rotation shafts 61 and 71 is not particularly limited as long as the rotation shafts 61 and 71 can be rotated.
Further, openings may be provided in the planar portions of the cam members 60 and 70, and the vibrating bodies 66 and 76 may be disposed in the openings, and the vibrating bodies 66 and 76 may be brought into contact with the outer peripheral surfaces of the rotating shafts 61 and 71. . In this case, the size of the opening has a size that does not come into contact with the vibrating bodies 66 and 76 even when the cam members 60 and 70 are rotated. In this case, the vibrating bodies 66 and 76 may be supported on either the outer surface portions 25A and 25B of the housing 20 or the cover member 10A.
In addition, on the outer peripheral surfaces of the rotating shafts 61 and 71, particularly the contact portions of the vibrating bodies 66 and 76 are finished without unevenness in order to prevent wear. The larger the outer diameter of the contact portion of the vibrating bodies 66 and 76 is, the better. Since this reduces the rotation angle with respect to the frequency, the lenses 30, 40 and 50 can be finely driven. And as for the outer-diameter shape of the rotating shafts 61 and 71, only a contact part is a circular arc, and the other surface does not need to be a circular arc in particular.

As shown in FIGS. 5 and 6, the vibrating body 66 includes a reinforcing plate 81 formed in a substantially rectangular flat plate shape, and a substantially rectangular flat plate-shaped piezoelectric element 82 provided on both the front and back surfaces of the reinforcing plate 81. ing.
A substantially semicircular concave notch 811 is formed at the approximate center of the short side of the reinforcing plate 81 near the pivot shaft 61. A substantially circular convex member 81 </ b> A is disposed in the notch 811. The convex member 81A is made of a highly rigid arbitrary material such as ceramics, approximately half of which is disposed in the notch 811 of the reinforcing plate 81, and the remaining approximately half is disposed protruding from the short side of the reinforcing plate 81. Has been. The tip of the convex member 81 </ b> A is in contact with the outer peripheral surface of the contact rotation shaft 61. In addition, a substantially pentagonal convex portion 812 is formed integrally with the reinforcing plate 81 at the approximate center of the short side of the reinforcing plate 81 far from the rotation shaft 61. The convex portion 812 is not in contact with the rotating shaft 61 and is in a free state, so that it is easy to excite, and plays a role of assisting excitation of the entire vibrating body 66 when the vibrating body 66 starts to vibrate.

  Arm portions 81 </ b> B projecting on both sides in the width direction are integrally formed at substantially the center in the longitudinal direction of the reinforcing plate 81. The arm portion 81B protrudes from the reinforcing plate 81 at a substantially right angle, and these end portions are fixed to the cover member 10A by screws (not shown). Such a reinforcing plate 81 is made of stainless steel or other conductive material. On the surface of the arm portion 81B of the reinforcing plate 81, a lead substrate 84 is provided. A conductive pattern 841 is formed on the lead substrate 84 on the surface opposite to the surface in contact with the reinforcing plate 81, and the conductive pattern 841 applies a voltage to the piezoelectric element 82 of the vibrating body 66 (not shown). Connected to the device. Further, another conductive pattern (not shown) is formed on the surface of the lead substrate 84 that contacts the reinforcing plate 81, and this conductive pattern is electrically connected to the reinforcing plate 81.

Piezoelectric elements 82 adhered to the substantially rectangular portions on both sides of the reinforcing plate 81 are lead zirconate titanate (PZT), crystal, lithium niobate, barium titanate, lead titanate, lead metaniobate, polyvinylidene fluoride, It is made of a material appropriately selected from materials such as lead zinc niobate and lead scandium niobate. In the present embodiment, the piezoelectric element 82 has a rectangular shape with a short side of about 1 mm and a long side of about 3.5 mm.
By forming a nickel plating layer, a gold plating layer, and the like on both surfaces of the piezoelectric element 82, a back side electrode 85A formed on the surface facing the reinforcing plate 81 and a surface opposite to the back side electrode 85A are formed. The front side electrode 85B is formed.

The back-side electrodes 85A are electrically insulated from each other by the cutout grooves, so that a plurality of back-side electrodes 85A are formed symmetrically about the center line along the longitudinal direction. That is, a groove 83A is formed along the longitudinal direction at the center in the short direction of the piezoelectric element 82, and a groove 83B is formed along the short direction at the center in the longitudinal direction. By these grooves 83A and 83B, a plurality of (four in the present embodiment) back-side electrodes 85A having substantially the same shape are formed on the surface of the piezoelectric element 82, respectively. Of the four corners of each back-side electrode 85A, the corner on the center side in the longitudinal direction of the piezoelectric element 82 and on the end side in the short direction is formed smaller than the outer shape of the piezoelectric element 82. With this shape, the piezoelectric element 82 is formed. An exposed portion 82A where the piezoelectric element 82 is exposed without the back-side electrode 85A being formed is formed at substantially the center in the longitudinal direction on the long side. The exposed portion 82A is a portion with which a part of the arm portion 81B of the reinforcing plate 81 comes into contact, and the piezoelectric element 82 and the reinforcing plate 81 are insulated in the exposed portion 82A. .
Here, an insulating layer 813 (see FIG. 7) made of an insulating material is formed at a portion of the reinforcing plate 81 where the piezoelectric element 82 is bonded. The insulating layer 813 insulates the back side electrode 85A and the reinforcing plate 81 from each other.

FIG. 7 shows a conduction structure between the back-side electrode 85A and the lead substrate 84. As shown in FIG. 7 and FIG. 6 described above, the back side electrode 85A and the lead substrate 84 are electrically connected by a back side electrode conducting portion 86 that conducts the back side electrodes 85A. The back-side electrode conductive portion 86 is configured by a conductive portion 861 disposed between the back-side electrodes 85A and an overhang portion 841A as a lead extending from the conductive pattern 841 of the lead substrate 84.
A concave portion 814 that is recessed inward from the long side is formed near the center of the long side of the reinforcing plate 81 in the longitudinal direction. The number of the recesses 814 is four (four in this embodiment) corresponding to the number of the back-side electrodes 85 </ b> A, and these recesses 814 are recessed from the side end surface of the piezoelectric element 82. In the piezoelectric elements 82 on both sides of the plate 81, the respective back side electrodes 85A are exposed. By such recesses 814, spaces 86A each having an opening are formed by each recess 814 and the piezoelectric elements 82 on both sides of the reinforcing plate 81. Note that an insulating layer 813A is formed on the inner surface of the recess 814, that is, the surface of the reinforcing plate 81 that contacts the space 86A.

The conductive portion 861 is formed by filling the space 86A with a conductive material such as solder cream or conductive paste. By this conducting portion 861, the back side electrodes 85 </ b> A of the piezoelectric elements 82 provided on both surfaces of the reinforcing plate 81 are electrically connected to each other. At this time, the reinforcing plate 81 and the conducting portion 861 are insulated by the insulating layer 813A. Thus, by forming the conducting portion 861 in each recess 814, the corresponding back side electrodes 85A on both sides are conducted with the reinforcing plate 81 interposed therebetween.
The leading end of the overhang portion 841A is connected to the conductive portion 861, so that the conductive portion 861 and the conductive pattern 841 of the lead substrate 84 are conductive. That is, the back-side electrode 85A and the conduction pattern 841 are conducted by the back-side electrode conducting portion 86.

FIG. 8 shows the conduction structure of the front electrode 85B. Here, FIG. 8 is a VIII-VIII cross-sectional view of FIG. As shown in FIG. 8, the front electrode 85 </ b> B is electrically connected to the reinforcing plate 81 by the front electrode conductive portion 87. The front-side electrode conducting portion 87 is provided at one location approximately in the center in the longitudinal direction of one of the long sides of the piezoelectric element 82, and is covered with solder over the end portion of the front-side electrode 85 </ b> B of the piezoelectric element 82 and the reinforcing plate 81. Is formed. The front-side electrode conducting portions 87 are provided on both surfaces of the reinforcing plate 81, and the front-side electrodes 85 </ b> B of the piezoelectric elements 82 on both surfaces of the reinforcing plate 81 are electrically connected to the reinforcing plate 81. The reinforcing plate 81 is electrically connected to another conductive pattern formed on the surface of the lead substrate 84 that faces the reinforcing plate 81. The other conductive pattern is connected to the ground so that the front electrode 85B is connected to the other. It is connected to the ground through a conductive pattern.
Here, since the portion corresponding to the position where the front-side electrode conducting portion 87 is provided in the back-side electrode 85A is formed inwardly, the exposed portion 82A is formed in the piezoelectric element 82, and the front-side electrode conducting portion 87 and the back side are formed. There is no electrical connection with the electrode 85A. In FIG. 8, although there is a gap between the exposed portion 82A and the reinforcing plate 81, in reality, the back electrode 85A and the insulating layer 813 have a small thickness, and therefore no gap is formed. The exposed portion 82A and the reinforcing plate 81 are in contact with each other.

  The vibrating body 66 formed in this way selects a predetermined electrode from among the plurality of backside electrodes 85A, and connects the backside electrode 85A and the frontside electrode 85B via the conduction pattern 841 of the lead substrate 84 by an application device (not shown). By applying a voltage between them, vibration in the longitudinal primary vibration mode as a longitudinal vibration mode that expands and contracts along the longitudinal direction of the vibrating body 66 and bending vibration in the width direction (short direction) of the vibrating body 66 are obtained. That is, vibration in the bending secondary vibration mode as a bending vibration mode that bends in a direction substantially orthogonal to the vibration direction of the longitudinal primary vibration mode can be generated in the vibrating body 66. That is, for example, when a voltage is applied only to the two back side electrodes 85A on the diagonal line among the back side electrodes 85A, the piezoelectric element 82 in the portion where the back side electrodes 85A are formed expands and contracts in the in-plane direction of the plate. Excites vibration in the longitudinal primary vibration mode. At this time, since no voltage is applied to the other two back-side electrodes 85A, the vibration in the longitudinal primary vibration mode is inhibited in that portion, and the vibration behavior of the entire vibrator 66 becomes unbalanced along the longitudinal center line. . As a result, the vibrating body 66 excites vibrations in a bending secondary vibration mode that bends in a direction substantially orthogonal to the longitudinal direction of the vibrating body 66. As a result, the convex member 81A of the vibrating body 66 vibrates while drawing a substantially elliptical orbit combining the vibration in the longitudinal primary vibration mode and the vibration in the bending secondary vibration mode. In a part of the substantially elliptical orbit, the convex member 81A rotates the rotation shaft 61 in the tangential direction.

In addition, when the vibrating body 66 is vibrated by appropriately switching the electrodes of the voltage applied to the piezoelectric element 82, the rotation direction of the rotation shaft 61 can be rotated forward and backward.
For example, if the rotation direction when a voltage is applied to the back side electrode 85A on one diagonal among the back side electrodes 85A is normal, if the voltage is applied to the back side electrode 85A on the other diagonal, The direction of the mode vibration is reversed, and the rotation direction of the rotation shaft 61 is reversed.
The drive frequency of the drive voltage (drive signal) applied to the piezoelectric element 82 is such that when the vibrating body 66 vibrates, a resonance point of vibration in the bending secondary vibration mode appears in the vicinity of the resonance point of vibration in the longitudinal primary vibration mode. The convex member 81A is set to draw a good substantially elliptical orbit.

  9 and 10 are diagrams illustrating vibration modes of the vibrating body 66. FIG. Here, FIG. 9 is a diagram illustrating the amplitude of the longitudinal primary vibration mode of the vibrating body 66, and FIG. 10 is a diagram illustrating the amplitude of the bending secondary vibration mode of the vibrating body 66. As shown in FIG. 9, the longitudinal primary vibration mode of the vibrating body 66 vibrates with the approximate center in the longitudinal direction of the piezoelectric element 82 as a vibration node A <b> 1. Therefore, the vibration body 66 has the smallest vibration amplitude in the longitudinal primary vibration mode at the vibration node A1. On the other hand, as shown in FIG. 10, the bending secondary vibration mode of the vibrating body 66 vibrates with the vibration element A <b> 2, B <b> 2 at approximately the center in the longitudinal direction of the piezoelectric element 82 and the vicinity of both ends in the longitudinal direction. Further, a vibration antinode C2 having the maximum vibration amplitude is formed between the vibration node A2 and the vibration node B2. In such a vibrating body 66, the vibration nodes A1 and A2 coincide with each other. Therefore, the vibration body 66 vibrates as a whole with the vibration nodes A1 and A2 as vibration nodes.

  Here, it is desirable that the concave portion 814 is disposed in the vicinity of the vibration nodes A1 and A2, and in this embodiment, the concave portion 814 is in the longitudinal primary vibration mode and the bending secondary vibration mode with respect to the longitudinal direction of the reinforcing plate 18. Near the vibration nodes A1 and A2, near the vibration nodes A1 and A2 from the midpoint between the vibration antinode C2 and the vibration nodes A1 and A2 in the vicinity of the vibration nodes A1 and A2.

The dimensions, thickness, material, aspect ratio, electrode division form, and the like of the piezoelectric element 82 are appropriately determined so that the convex member 81A can easily draw a good substantially elliptical orbit when a voltage is applied to the piezoelectric element 82. The
The waveform of the AC voltage applied to the vibrating body 66 is not particularly limited, and for example, a sine wave, a rectangular wave, a trapezoidal wave, or the like can be employed.
Further, the vibrating body 76 has the same configuration as that of the vibrating body 66 and can be understood by describing the vibrating body 66, and therefore description thereof is omitted here.

Next, the operation of the lens unit 10 will be described with reference to FIG.
First, when the vibrating body 66 in contact with the outer periphery of the rotation shaft 61 vibrates, the rotation shaft 61 rotates at a predetermined angle. By rotating, the cam member 60 integrated with the rotating shaft 61 also rotates at a predetermined angle. Then, the cam grooves 62A and 62B formed in the cam member 60 also rotate, and the outer peripheral surfaces of the cam bars 51 and 41 fitted in the cam grooves 62A and 62B are caused by the inner peripheral surfaces of the cam grooves 62A and 62B. It moves in the openings 23A and 23B while being guided.
For example, when the rotation shaft 61 is rotated counterclockwise (R1) from the position of FIG. 3A, the second lens 40 and the third lens 50 having the cam bars 41 and 51 are separated from each other. As shown in FIG. 3B, the distance between the second lens 40 and the third lens 50 is increased.
On the other hand, when the back side electrode 85A to which the voltage is applied is switched to the back side electrode 85A on the other diagonal line, the rotation shaft 61 is rotated clockwise (R2) from the position of FIG. The lens 40 and the third lens 50 move in directions close to each other and return as shown in FIG.
Thereby, the second lens 40 and the third lens 50 function as a zoom lens.

Similarly, in FIG. 4, the vibration shaft 76 that is in contact with the outer periphery of the rotation shaft 71 vibrates, whereby the rotation shaft 71 rotates at a predetermined angle. By rotating, the cam member 70 integrated with the rotating shaft 71 also rotates at a predetermined angle. Then, the cam groove 62C formed in the cam member 70 also rotates, and the outer peripheral surface of the cam bar 31 fitted in the 62C moves in the opening 23C while being guided by the inner peripheral surface of the cam groove 62C. .
For example, when the rotation shaft 71 is rotated counterclockwise (R1) from the position of FIG. 4A, the first lens 30 connected to the cam rod 51 is moved outward from the center direction of the housing 20. It moves and approaches the end side of the housing 20 as shown in FIG.
On the other hand, when the rotation shaft 71 is rotated clockwise (R2) from the position of FIG. 4B, the first lens 30 moves to the center side of the housing 20, as shown in FIG. 4A. Return to.
As a result, the first lens 30 functions as a focus lens.

As described above, the first lens 30, the second lens 40, and the like are directly applied to the rotating shafts 61 and 71 of the cam members 60 and 70 while appropriately switching the back-side electrode 85 </ b> A that applies a voltage to the piezoelectric element 82. The third lens 50 is driven back and forth as shown in FIGS.
At this time, the positions of the lenses 30, 40, and 50 are read by a reading sensor (not shown), and are fed back to the control circuit for drive control, so that the lenses 30, 40, and 50 can be stopped at an arbitrary position.

According to the above first embodiment, the following effects can be obtained.
(1) The back side electrode 85A and the reinforcing plate 81 are insulated by the insulating layer 813 to form a plurality of back side electrodes 85A, and the back side electrodes 85A facing each other on both sides of the reinforcing plate 81 are made conductive by the back side electrode conducting portion 86. Unlike the conventional case where a plurality of electrodes are formed on the front side, it is not necessary to arrange the lead substrate 84 at a predetermined distance from the front side electrode 85B in order to prevent the overhang portion 841A from coming into contact with other electrodes. . That is, since the lead substrate 84 can be provided in contact with the surface of the arm portion 81B, the thickness and size of the vibrating bodies 66 and 76 can be promoted. Thereby, thickness reduction and size reduction of the lens unit 10 can be promoted.
At this time, since there is only one front electrode 85B, the conduction structure with the lead substrate 84 can be simplified. Since the front electrode 85B is electrically connected to the arm portion 81B of the reinforcing plate 81 by the front electrode conductive portion 87, it is not necessary to overlap the substrate with a predetermined distance from the front electrode 85B. 76 can be made thinner and smaller.

 (2) Since the plurality of back-side electrodes 85A are electrically connected to each other by the conducting portion 861, the back-side electrodes 85A are electrically connected to each other. Therefore, unlike the conventional case where a plurality of electrodes are formed on the front side, the substrate for conducting the electrodes is folded. Therefore, it is not necessary to conduct on both sides of the reinforcing plate. Accordingly, since the back electrode 85A of the piezoelectric element 82 on both surfaces of the reinforcing plate 81 can be made conductive with one lead substrate 84, this can also promote the reduction in thickness and size of the vibrators 66 and 76, and the back electrode. The conduction work between 85A and the lead substrate 84 can be simplified, and the vibrators 66 and 76 can be easily manufactured.

 (3) Since the concave portion 814 is formed in the reinforcing plate 81 at a position corresponding to each back-side electrode 85A, and the conductive portion 861 is formed in each of the concave portions 814, the conductive portion 861 does not protrude from the side surface of the piezoelectric element 82. Therefore, it is possible to prevent the conduction portion 861 from coming off due to a disturbance, so that the back electrode 85A and the lead substrate 84 can be reliably conducted.

 (4) Since the conductive portion 861 is formed by filling the space 86A with a conductive material in the form of a paste, the conductive portion 861 can be easily formed and the conductive portion 861 can be formed without a gap in the space 86A. The back-side electrodes 85A can be reliably connected to each other.

 (5) Since the reinforcing plate 81 is made of a conductive material and the insulating layers 813 and 813A are formed on the portion of the reinforcing plate 81 that contacts the back electrode 85A, a plurality of electrodes may be provided on the back electrode 85A. It is possible to prevent conduction with each other. Further, since the reinforcing plate 81 is made of a conductive material, the front electrode 85B is connected to the applying device via the lead substrate 84 by connecting the front electrode 85B to the reinforcing plate 81 and connected to the applying device via the lead substrate 84. Can be connected to. Therefore, the conduction structure of the front electrode 85B can be simplified. In addition, since the front electrode 85B and the reinforcing plate 81 can be conducted without using a lead wire or the like, it is possible to reliably prevent the occurrence of problems such as disconnection.

 (6) Since the concave portion 814 is formed in the vicinity of the vibration nodes A1 and A2 of the vibrating bodies 66 and 76, and therefore, the back-side electrode conducting portion 86 is disposed in the vicinity of the vibration nodes A1 and A2 of the vibrating bodies 66 and 76. The electrode conducting portion 86 does not hinder the vibration of the vibrating bodies 66 and 76, and the driving efficiency of the vibrating bodies 66 and 76 can be improved. Further, since the back-side electrode conducting portion 86 is disposed in the vicinity of the vibration nodes A1 and A2 of the vibrating bodies 66 and 76, the vibration amplitude of the vibrating bodies 66 and 76 at the position is relatively small. 86 and the overhang portion 841A can be prevented from being disconnected.

 (7) Since the vibrating bodies 66 and 76 are formed in a plate shape, it is possible to promote a reduction in the thickness of the drive device 1, thereby promoting a reduction in the size of the lens unit 10. Further, since the convex member 81A is in contact with the rotating shafts 61 and 71, when the vibration of the vibrating bodies 66 and 76 is stopped, friction between the convex member 81A and the outer periphery of the rotating shafts 61 and 71 is caused. The rotation angle of the rotation shafts 61 and 71 can be maintained.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. The second embodiment is different from the first embodiment in the structure of the back-side electrode conducting portion, and the other configurations are the same as those of the first embodiment.
FIG. 11 shows a side sectional view of the vibrating body 66 according to the second embodiment of the present invention. FIG. 11 is a side sectional view at a position where the concave portion 814 is formed. As shown in FIG. 11, the conducting portion 861 is provided at the tip of the overhang portion 841 </ b> A, and is formed in a protruding shape that protrudes toward both sides in the thickness direction of the reinforcing plate 81. Both ends of the conductive portion 861 are in pressure contact with the respective back-side electrodes 85A. When connecting such a conducting portion 861 to each backside electrode 85A, first, the reinforcing plate 81 is joined to one piezoelectric element 82, and the conducting portion 861 is disposed in the recess 814. After that, when the other piezoelectric element 82 is put on the reinforcing plate 81 and joined, the conducting portion 861 is pressed by the opposing piezoelectric element 82, and the conducting portion 861 is pressed into and energized into the back side electrodes 85A on both sides.
In the second embodiment, since the projecting conductive portion 861 is in pressure contact, as shown in FIG. 11, the insulating layer 813A as in the first embodiment may not be formed on the inner surface of the recess 814. . In addition, solder may be supplied to both ends of the conducting portion 861 in order to ensure conduction with the back-side electrode 85A.

According to such a second embodiment, the following effects can be obtained in addition to the same effects as the effects (1) to (3) and (5) to (7) of the first embodiment. .
(8) Since the back-side electrode conducting portion 86 is formed in a protruding shape and pressed against the back-side electrode 85A, the back-side electrode 85A can be reliably conducted. Further, since the back-side electrode conducting portion 86 is pressure-bonded to the back-side electrode 85A, it is possible to reliably prevent the back-side electrode conducting portion 86 from coming off. Thereby, it is possible to prevent problems such as disconnection of the back-side electrode conducting portion 86 due to vibrations or disturbances of the vibrating bodies 66 and 76.

[Third embodiment]
Next, a third embodiment of the present invention will be described. The third embodiment is the same as the first embodiment except that the configurations of the reinforcing plate 81 and the front-side electrode conducting portion 87 in the first embodiment are different.
In the second embodiment, the reinforcing plate 81 is made of any non-conductive material such as ceramics. For this reason, even if the reinforcing plate 81 and the back side electrode 85A are in contact with each other, they are insulated from each other. Therefore, the insulating layer 813 as in the first embodiment is formed on the portion of the reinforcing plate 81 in contact with the back side electrode 85A. 813A is not formed.

  FIG. 12 shows a vibrating body 66 according to the third embodiment of the present invention. As shown in FIG. 12, a conductive portion 88 is formed on the arm portion 81B of the reinforcing plate 81 by plating or the like. The conductive portion 88 is formed so as to penetrate in the thickness direction of the arm portion 81B, and is also exposed on the surface opposite to the arm portion 81B. The front-side electrode conducting portion 87 is formed on both surfaces of the arm portion 81B, and is in contact with the front-side electrode 85B and the conductive portion 88 to conduct both. The conductive portion 88 is electrically connected to the conductive pattern 841 by the overhang portion 841A from the lead substrate 84 on the surface where the lead substrate 84 is provided. With such a structure, the front electrodes 85B on both sides of the reinforcing plate 81 are electrically connected to the conductive pattern 841 of the lead substrate 84.

According to the third embodiment, in addition to the same effects as the effects (1) to (4), (6), and (7) of the first embodiment, the following effects are obtained. It is done.
(9) Since the reinforcing plate 81 is made of a non-conductive material, it can be insulated from the back side electrode 85A without forming an insulating layer between the back side electrode 85A, so that the configuration of the reinforcing plate 81 can be simplified.
Further, since the conductive portion 88 is formed on the reinforcing plate 81, the front-side electrode conducting portion 87 can be conducted to the conductive portion 88 of the reinforcing plate 81, so that the reinforcing plate 81 is made of a nonconductive material. The conduction structure of the front electrode 85B can be simplified, and the vibrating bodies 66 and 76 can be made thinner and smaller.

It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
The back side electrode conducting portion is not limited to the one in each embodiment, and any configuration capable of conducting the opposing back side electrodes can be adopted. For example, in the back side electrode conducting portion 86 of the second embodiment, the space 86A may be filled with a conductive material such as solder or a conductive adhesive. In this case, an insulating layer may be formed on the inner surface of the recess 814.
Moreover, the back side electrode conduction | electrical_connection part is not restricted to the structure filled with materials with viscosity, such as a solder cream and a conductive adhesive, For example, the structure which connects back side electrodes directly with a lead wire may be sufficient.
Note that the back side electrode conducting portion is not limited to the configuration in which the back side electrodes are directly connected to each other, and for example, the back side electrode is connected to the lead substrate, and the lead substrate is connected to the common conduction pattern, thereby conducting the connection. A configuration in which conduction is indirectly performed through a pattern is also included.

The connection between the back-side electrode conductive portion and the conductive pattern of the substrate is not limited to the overhang portion. For example, the back-side electrode and the substrate are connected through another member, or a spring is provided between the opposing back-side electrodes to each other. It is good also as composition which makes it conduct.
FIG. 13 is a diagram showing a modification of the present invention. In FIG. 13, the back-side electrode conducting portion 86 and the conducting pattern 841 are conducted by the lead wire 842. According to such a configuration, the lead substrate 84 is first attached to the reinforcing plate 81, and then the back-side electrode conducting portion 86 and the conducting pattern 841 can be connected by the lead wire 842, so that the degree of freedom in the work procedure is increased. Can do.

The front-side electrode conducting portion is not limited to the configuration that conducts the front-side electrode and the reinforcing plate, and for example, as shown in FIG. You may make it conduct. In this case, the front-side electrode 85B can be conducted to the lead substrate 84 regardless of whether the reinforcing plate 81 is a conductive material or a non-conductive material, thereby increasing the degree of freedom in selecting the material of the reinforcing plate 81. Can do.
The formation position of the back side electrode conducting portion is not limited to the concave portion of the reinforcing plate. For example, the outer side shape of the piezoelectric element (for example, the short side dimension) is formed larger than the reinforcing plate, and the back side electrode of the portion where the piezoelectric element protrudes from the reinforcing plate May be provided. Or the protrusion part which protrudes from a reinforcement board may be formed in a piezoelectric element, and a back side electrode conduction | electrical_connection part may be provided so that the back side electrode which opposes in this protrusion part may be conducted.

In each embodiment, solder may be supplied to a joint portion between the back-side electrode conducting portion and the back-side electrode. In this case, the solder may be supplied by, for example, solder plating on the entire conductive pattern of the lead substrate, or may be supplied only to the overhang portion of the conductive pattern of the lead substrate by a dispensing method. .
Here, when solder plating is applied to the overhang portion, the entire conductive pattern of the lead substrate is coated with solder. On the other hand, when supplying solder by the dispensing method, a desired amount is supplied only to a portion (overhang portion) where solder is required. Therefore, for example, the entire conductive pattern is formed by gold plating, solder is supplied only to the overhang portion and joined to the back side electrode, and other conductive patterns are formed on the conductive pattern using the low connection resistance of the gold plating. It is also possible to connect components. According to such a configuration, it is possible to improve the structural freedom in the arrangement of components.

The best configuration, method and the like for carrying out the present invention have been disclosed in the above description, but the present invention is not limited to this. That is, the invention has been illustrated and described primarily with respect to particular embodiments, but may be configured for the above-described embodiments without departing from the scope and spirit of the invention. Various modifications can be made by those skilled in the art in terms of materials, quantity, and other detailed configurations.
Therefore, the description limited to the shape, material, etc. disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such restrictions is included in this invention.

The perspective view which shows the lens unit concerning 1st embodiment of this invention. The perspective view which shows the lens unit concerning 1st embodiment. The operation | movement figure of the cam member of 1st embodiment. The operation | movement figure of the cam member of 1st embodiment. The expansion perspective view of the vibrating body of a first embodiment. FIG. 3 is a partially enlarged perspective view of the vibrating body according to the first embodiment. VII-VII sectional drawing of FIG. VIII-VIII sectional drawing of FIG. The figure which shows the amplitude of the longitudinal primary vibration mode of the vibrating body of 1st embodiment of this invention. The figure which shows the amplitude of the bending secondary vibration mode of the vibrating body of 1st embodiment of this invention. The sectional side view of the vibrating body concerning 2nd embodiment of this invention. The perspective view of the vibrating body of 3rd embodiment of this invention. The perspective view which shows the modification of the vibrating body of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Drive device, 10 ... Lens unit (equipment), 61, 71 ... Rotating shaft, 66, 76 ... Vibrating body (piezoelectric actuator), 81 ... Reinforcing plate, 81B ... Arm part, 82 ... Piezoelectric element, 84 ... Lead Substrate, 85A ... back side electrode, 85B ... front side electrode, 86 ... back side electrode conducting part, 87 ... front side electrode conducting part, 813, 813A ... insulating layer, 814 ... concave part, 841 ... conduction pattern, 841A ... overhang part (lead) , 842 ... lead wires.

Claims (5)

A rectangular piezoelectric element in which a front electrode and a back electrode are formed;
A reinforcing plate having substantially the same shape as the piezoelectric element, the piezoelectric element being disposed on both sides and insulated from the piezoelectric element ;
A lead substrate formed with a conduction pattern for applying a voltage to the piezoelectric element;
An overhang portion for conducting the back side electrode and a conductive pattern for the back side electrode of the lead substrate ;
Wherein the piezoelectric element, the rear electrode on a surface in contact with the reinforcing plate is formed with a plurality, wherein the back side electrode is the front electrode on the opposite side is formed,
The reinforcing plate is integrally formed with an arm portion protruding in the width direction, and has a recess formed by cutting out a part of the long side of the reinforcing plate so that the opposing backside electrodes of the both surfaces face each other. Formed,
The lead substrate is disposed on the arm portion,
The space formed by the back-side electrodes on both sides and the recesses is filled with a conductive material,
The piezoelectric actuator , wherein the overhang portion and the back electrode are electrically connected through the conductive material. The piezoelectric actuator according to claim 1,
The reinforcing plate is made of a conductive material,
An insulating layer is formed on the surface of the reinforcing plate that contacts the back electrode and the surface that contacts the conductive material filled in the recess ,
The front electrode is electrically connected to the reinforcing plate;
The piezoelectric actuator is characterized in that the reinforcing plate is electrically connected to a conductive pattern for a front side electrode of the lead substrate . The piezoelectric actuator according to claim 1,
The reinforcing plate is made of a non-conductive material,
The front side electrode is conducted to a conduction part formed on an arm part of the reinforcing plate,
The piezoelectric actuator according to claim 1, wherein the conductive portion is conductive to a conductive pattern for a front side electrode of the lead substrate . The piezoelectric actuator according to any one of claims 1 to 3,
The concave portion is disposed in the vicinity of a vibration node of the piezoelectric actuator.   An apparatus comprising the piezoelectric actuator according to any one of claims 1 to 4.

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