WO2014091656A1

WO2014091656A1 - Drive device and imaging device

Info

Publication number: WO2014091656A1
Application number: PCT/JP2013/006133
Authority: WO
Inventors: 小坂　明; 松尾　隆; 久保　直樹
Original assignee: コニカミノルタ株式会社
Priority date: 2012-12-12
Filing date: 2013-10-15
Publication date: 2014-06-19
Also published as: JP5565541B1; JPWO2014091656A1

Abstract

In this drive device and this imaging device, a drive unit is supported by a fixed member by using an external-force alleviating support unit, said drive unit generating a prescribed drive force caused by the expansion/contraction operation of an electromechanical conversion element. If an external force has been received in a direction differing from the direction that the drive unit expands/contracts, this external-force alleviating support unit alleviates the impact of the external force on the drive unit.

Description

Driving device and imaging device

The present invention relates to a drive device using an electromechanical transducer and an imaging device using the drive device.

There is known a driving device including an actuator composed of an electromechanical conversion element, a driving member, and an engaging member (hereinafter also referred to as a moving member). An electromechanical transducer is an element that converts applied electrical energy into mechanical motion. For example, the electromechanical conversion element is a piezoelectric element in which a plurality of piezoelectric layers made of a piezoelectric material are stacked via internal electrodes between the piezoelectric layers. For example, when a saw-tooth drive pulse is applied to the electromechanical conversion element, the electromechanical conversion element expands and contracts (hereinafter, the expansion / contraction direction of the electromechanical conversion element is also referred to as an axial direction). The expansion / contraction direction is the above-described stacking direction. The electromechanical transducer is usually fixed to a housing that houses the actuator. The drive member is fixed to the electromechanical conversion element inside the housing. The drive member has a long shape along the axial direction. The electromechanical conversion element and the drive member are sequentially connected along the axial direction. By applying a sawtooth drive pulse to the electromechanical transducer, the electromechanical transducer expands and contracts to generate a driving force, and the driving force causes the driving member to move along its longitudinal direction, that is, the axial direction. Reciprocates. The engagement member is engaged with the drive member with a predetermined frictional force (hereinafter also referred to as friction engagement), and moves in the axial direction in accordance with the reciprocating movement of the drive member.

More specifically, this type of driving device operates on the following principle of operation. A sawtooth drive pulse having a gently rising portion and a rapidly falling portion is applied to the electromechanical transducer. Thereby, each operation | movement of the expansion and contraction in expansion / contraction of the electromechanical conversion element becomes different speed. At the gently rising portion of the drive pulse, the electromechanical transducer is gently extended in one direction of the shaft, and the drive member fixed to the electromechanical transducer is also gradually displaced in one direction of the shaft. At this time, the moving member does not displace with respect to the driving member due to the static frictional force, and moves in one axial direction with respect to the housing together with the driving member. In the rapidly falling portion of the sawtooth drive pulse, the electromechanical conversion element rapidly contracts in a direction opposite to one direction of the axis, and the drive member is fixed to the electromechanical conversion element accordingly. Is rapidly displaced in a direction opposite to one direction of the axis. At this time, an inertia force larger than the static friction force acts on the moving member that is frictionally engaged with the driving member, and the moving member causes a so-called slip in the one direction with respect to the displaced driving member. The predetermined frictional force is usually a force that does not cause the moving member to be displaced by the static frictional force with respect to the driving member. However, the moving member does not slip as a result of rapid displacement of the driving member. It is the power of the size to wake up. As a result, the moving member stays substantially at that position with respect to the housing and hardly moves.

By the above operation, the moving member moves in one axial direction with respect to the housing. The sawtooth wave drive pulse is continuously applied to the electromechanical transducer, and the above operation is repeated, whereby the moving member can continuously move in one direction of the axis. On the other hand, the operation of moving the moving member in the reverse direction is achieved by applying a sawtooth drive pulse having a changed waveform to the electromechanical transducer. That is, this is achieved by applying a sawtooth drive pulse consisting of a rapid rising portion and a gentle falling portion to the electromechanical transducer.

An actuator that performs the above operation may be referred to as an impact type actuator. In such a drive device in which the impact type actuator is used, in order to reliably transmit the displacement of the electromechanical conversion element to the drive member, the electromechanical conversion element and the drive member are bonded and fixed by, for example, an adhesive. Both the conversion element and the housing are bonded and fixed by, for example, an adhesive. In addition, the electromechanical conversion element and the housing may be directly fixed, or the electromechanical conversion element and the housing may be fixed via an inclusion therebetween. In this case, the inclusion and the electromechanical conversion element, and the inclusion and the housing are bonded and fixed by, for example, an adhesive.

According to Patent Document 1, a compressive force and a tensile force due to expansion and contraction of the electromechanical conversion element are alternately applied to the adhesively fixed portion between the electromechanical conversion element and the driving member, It has been disclosed that the adhesive fixing portion may loosen and peel off over a long period of time due to the expansion and contraction. In addition, since sound is generated by vibration (reciprocal displacement) of the drive member or the like, a high-frequency drive pulse exceeding an audible range of about 20 to 30 kHz is applied to the electromechanical transducer to suppress this sound. It is also disclosed that there is a possibility that the bonded portion may be more easily peeled off. In order to solve these problems, in Patent Document 1, the coupling portion between the electromechanical transducer and the drive member is covered with a reinforcing member that integrally covers the base of the electromechanical transducer and the base of the drive member. With this reinforcing member, the bonded portion can be bonded with sufficient strength, and moisture can be prevented from entering to improve reliability against long-term driving and deterioration.

In such a driving apparatus, since the moving member moves along the driving member, at least the driving member has a length corresponding to the length of the portion where the moving member engages with respect to the length of the range in which the moving member moves. Only the added length is required. For this reason, the combined shape of the electromechanical conversion element and the driving member is a shape elongated in the longitudinal direction of the driving member. As a result, when an external force in a direction different from the axial direction is applied to the driving device due to an impact of the driving device falling, the driving member is long in the longitudinal direction, and the members of the driving device are bonded and fixed. For this reason, the driving device is weak against bending stress generated by the external force. That is, when such a bending stress occurs, the drive device may be damaged. Further, since the electromechanical conversion element has a structure in which the electromechanical conversion element is laminated in the axial direction as described above, the electromechanical conversion element itself may be damaged when such bending stress is generated.

In the prior art, a reinforcing member that covers a coupling portion between the electromechanical conversion element and the driving member is disclosed. However, when the external force is applied, the connection portion between the electromechanical conversion element and the reinforcing member and the connection portion between the driving member and the reinforcing member may be damaged. In addition, as described above, the driving member having an elongated shape in the axial direction and the electromechanical conversion element laminated in the axial direction are vulnerable to bending stress, and the driving member itself caused by such bending stress is weak in the conventional reinforcing member. It is difficult to prevent damage to the electromechanical transducer itself.

JP-A-8-286093

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a drive device and an imaging device that can reduce breakage due to bending stress generated by an external force.

In the drive device and the imaging device according to the present invention, the drive unit that generates a predetermined drive force due to the expansion and contraction motion of the electromechanical transducer is supported by the fixed member by the external force relaxation support unit. The external force relaxation support portion reduces the influence of the external force on the drive unit when the drive unit receives an external force in a direction different from the direction of expansion and contraction.

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

It is sectional drawing showing the structure of the drive device concerning 1st Embodiment. It is a figure explaining the moving member of the drive device shown in FIG. It is a figure explaining the applied voltage applied to the drive device shown in FIG. 1, and the displacement operation | movement of a moving member. It is a figure explaining the support spring which can be used conveniently for the drive device shown in FIG. It is a figure explaining the effect | action and effect of the drive device shown in FIG. It is sectional drawing showing the structure of the drive device concerning 2nd Embodiment. It is a figure explaining an effect | action and effect of the drive device shown in FIG. It is sectional drawing showing the structure of the drive device concerning 3rd Embodiment. It is a perspective view explaining a part of drive device shown in FIG. It is sectional drawing explaining the structure of the imaging device concerning 4th Embodiment.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted suitably. Further, in this specification, when referring generically, it is indicated by a reference symbol without a suffix, and when referring to an individual configuration, it is indicated by a reference symbol with a suffix.

[Embodiment 1]
FIG. 1 shows an example of a drive device that moves, for example, a lens using the impact type actuator according to the present embodiment. In FIG. 1, the driving device 100 according to the present embodiment accommodates a driving unit 200, a lens L1, a lens holding frame (an example of an engaging member) 12, an external force relaxation support unit 21, and the inside thereof. A housing 31 not shown in its entirety and a drive circuit 30 are provided. The drive unit 200 has a plurality of members. The drive device 100 includes at least a drive shaft (an example of a drive member) 11 and a piezoelectric element (an example of an electromechanical conversion element) 18 as a plurality of members included in the drive unit 200. The drive unit 200 may include a base 19 and a reinforcing member 20 described later. The driving unit 200 generates a predetermined driving force by the driving force of each member itself, the interaction between the members, or the like. The drive part 200 is an actuator comprised from these several members, for example. The drive unit 200 and the lens holding frame 12 (moving member) constitute an impact type actuator. A guide rod for guiding the movement of the lens holding frame 12 may be present in the housing 31, but is not shown in the present embodiment.

The piezoelectric element 18 is an element that converts applied electric energy into mechanical energy, more specifically, an element that converts applied electric energy into expansion and contraction motion (mechanical energy to expand and contract). In this embodiment, the piezoelectric effect is used for this conversion. The piezoelectric element 18 includes, for example, a stacked body and a pair of external electrodes. The laminated body is configured by alternately laminating a plurality of thin film and layered piezoelectric layers made of a piezoelectric material and conductive thin film and layered internal electrode layers. The plurality of internal electrode layers are configured such that an electrode connected to the positive electrode of the power source for applying the electric energy and an electrode connected to the negative electrode are alternately arranged in parallel, and a piezoelectric layer is interposed between the electrodes. It is sandwiched. The pair of external electrodes are connected to the power source, are formed substantially parallel to the stacking direction, and sandwich the stack. In addition, a part of internal electrode faces the outermost side of a laminated body, and is connected to the said external electrode. The shape of the piezoelectric element 18 is, for example, a quadrangular prism shape, a polygonal column shape, a cylindrical shape, or the like. Examples of the piezoelectric material include lead zirconate titanate (so-called PZT), crystal, lithium niobate (LiNbO ₃ ), potassium tantalate niobate (K (Ta, Nb) O ₃ ), barium titanate (BaTiO ₃ ), Inorganic piezoelectric materials such as lithium tantalate (LiTaO ₃ ) and strontium titanate (SrTiO ₃ ).

One end of the drive shaft 11 is fixed to one end of the piezoelectric element 18 with respect to the axial direction (the expansion / contraction direction of the piezoelectric element 18, the direction a in FIG. 1). The The piezoelectric element 18 and the drive shaft 11 are sequentially connected along one direction (longitudinal direction of the drive shaft 11), and the longitudinal direction of the drive shaft 11 is parallel to the axial direction. The drive shaft 11 is supported by a support member 15 which is a part of the housing 31 so as to be movable in parallel with the axial direction. As the piezoelectric element 18 expands and contracts, the drive shaft 11 moves parallel to the axial direction, and more specifically, reciprocates (vibrates). The shape of the cross section perpendicular to the longitudinal direction of the drive shaft 11 is an arbitrary shape such as a rectangle, a polygon, an ellipse, and a circle. In the present embodiment, from the viewpoint that the moving member (the lens holding frame 12 in the example shown in FIG. 1) can be relatively moved along the drive shaft 11 in the longitudinal direction of the drive shaft 11, this cross section is circular. It is. In addition, when this cross section is a rectangle or a polygon, it is preferable that the corner | angular part is chamfered from the said viewpoint. As the material of the drive shaft 11, for example, any material such as metal, resin, and carbon can be used.

The lens holding frame 12 is a moving member that is engaged (frictionally engaged) with the drive shaft 11 by the above-described predetermined friction force, and slides in the axial direction along the drive shaft 11. In the present embodiment, the lens holding frame 12 supports a lens L1 that is an example of an optical element. The lens holding frame 12 has an extended portion that extends a part of its outer periphery, and a slider block 12a is formed in the extended portion. The slider block 12a is formed with a hole 12c penetrating and opening parallel to the optical axis of the lens L1, and the drive shaft 11 is inserted therethrough. In the present embodiment, the axial direction and the optical axis direction of the lens L1 are parallel. The cross section perpendicular to the axial direction of the hole 12 c is shaped and dimensioned according to the cross section perpendicular to the axial direction of the drive shaft 11 so that the lens holding frame 12 can move along the drive shaft 11. Yes, the cross section of the hole 12c is slightly larger than the cross section of the drive shaft 11. The lens holding frame 12 moves relative to the axial direction, but the movement range is between the support member 15 and the piezoelectric element 18.

The slider block 12a will be described with reference to FIG. 2A is a side view of the slider block 12a, and FIG. 2B is a front view. The hole 12c and the notch 12b are formed in the slider block 12a, and the pad 16 and the spring 17 are present therein. A hole 12c is formed in the approximate center of the slider block 12a, and a notch 12b is formed above the hole 12c. The upper portion of the drive shaft 11 is exposed in the notch 12b (the drive shaft 11 is not shown in FIG. 2 for explanation). A pad 16 that contacts the upper portion of the drive shaft 11 is fitted into the notch 12b. The pad 16 is applied with an urging force F downward in FIG. 2 (ie, directed toward the drive shaft 11) by the spring 17, and is brought into contact with and pressed against the drive shaft 11. When this urging force F by the spring 17 is applied to the pad 16, the slider block 12 a is frictionally engaged with the drive shaft 11 with the predetermined frictional force. The structure in which the drive shaft 11 and the slider block 12a are frictionally engaged is not limited to this.

Referring back to FIG. 1, the stationary portion 13 is a part of the housing 31 that is an example of the fixing member together with the support member 15. The casing 31 is a fixed member that is normally stationary with respect to the stationary system. The stationary part 13 is engaged with the piezoelectric element 18 via the external force relaxation support part 21 and supports the driving part 200. The stationary part 13 may support the driving part 200 by engaging with the piezoelectric element 18 between the stationary part 13 and the piezoelectric element 18 via the external force relaxation supporting part 21 and other inclusions.

The drive circuit 30 is a circuit that applies, for example, a sawtooth drive pulse to the piezoelectric element 18. When the drive circuit 30 continuously applies a sawtooth drive pulse to the piezoelectric element 18, the piezoelectric element 18 expands and contracts. The drive circuit 30 is a known oscillation circuit that oscillates a sawtooth drive pulse, for example. The frequency of the sawtooth drive pulse may be any frequency. If the frequency of the drive pulse is set to about 20 to 30 kHz, the expansion / contraction frequency of the piezoelectric element 18 and the vibration frequency of the drive shaft 11 are out of the audible range, and the vibration sound that can be heard by the human ear can be reduced.

3 is continuously applied to the piezoelectric element 18 by the sawtooth wave-like driving pulse indicated by the broken line in FIG. 3, the extending operation and the contracting operation of the piezoelectric element 18 are performed at different speeds. A driving force is generated at 18. With this driving force, the drive shaft 11 is driven so as to reciprocate at different speeds in one direction and the opposite direction corresponding to the expansion and contraction of the piezoelectric element 18. Since the lens holding frame 12 is engaged with the drive shaft 11 with a predetermined frictional force, the drive shaft 11 drives the housing 31 with the same operation principle as described in the background art. The lens holding frame 12, which is an example of a driven member, continuously moves in one direction relative to the axial direction or in the opposite direction. That is, the driving shaft 11 is driven by the driving force generated by the piezoelectric element 18, the predetermined driving force is generated in the driving unit 200, and the lens holding frame 12 receives the predetermined driving force from the driving unit 200. The lens holding frame 12 moves along the axial direction in response to the predetermined driving force. The predetermined driving force referred to in the present embodiment is, for example, a driving force that exceeds the degree that the lens holding frame 12 can move along the driving shaft 11 by overcoming the static friction force. In FIG. 3, the displacement in which the lens holding frame 12 moves in the axial direction with respect to the housing 31 is also indicated by a solid line. In FIG. 3, the vertical axis represents the voltage of the drive pulse applied to the piezoelectric element 18 and the displacement amount of the lens holding frame 12, and the horizontal axis represents time.

The drive circuit 30 may be a circuit that outputs, for example, a rectangular wave drive pulse. For example, the drive circuit 30 is rectangular when a predetermined duty ratio such as 3: 7 or 7: 3 (period is Tall, High voltage time is Ton, and Low voltage time is Toff (Tall = Ton + Toff)). For example, an H-bridge circuit using four known switching elements, a half-bridge circuit using two switching elements, and the like that oscillates as a driving pulse is a rectangular pulse having a ratio of Ton and Tall in a wave pulse). . Even when a rectangular drive pulse is output from the drive circuit 30, the vibration displacement waveform with respect to the time axis of the piezoelectric element 18 has a sawtooth shape similar to that when a sawtooth drive pulse is applied. This is because the gain (amplitude) of the third and higher harmonics of the harmonic component is greatly attenuated in the rectangular wave represented by the sine wave that is the fundamental wave and the multiple harmonics. Since it has a waveform composed of a fundamental wave and a second harmonic, it is considered that the pulse waveform is a sawtooth waveform.

Returning to FIG. 1, the external force relaxation support unit 21 supports the drive unit 200 from the axial direction, and when the drive unit 200 receives an external force in a direction different from the one direction (axial direction), the drive unit 200 is directed to the drive unit 200. Mitigates the influence of external forces to be applied. More specifically, the external force relaxation support portion 21 is an elastic member that absorbs external force in a direction perpendicular to the axial direction, for example. By absorbing the influence of the external force on the driving unit 200 with the elastic member, the influence of the external force is mitigated. The external force in a direction different from the one direction is also a component component in a direction different from the axial direction in an external force in an arbitrary direction. The external force relaxation support portion 21 is disposed between the other end of the piezoelectric element 18 in the axial direction and the stationary portion 13 of the housing 31. In the present embodiment, one end of the external force relaxation support portion 21 is engaged with the other end of the piezoelectric element 18. Further, the other end of the external force relaxation support portion 21 is engaged with a boss 13 a protruding from the stationary portion 13. In the present embodiment, adhesive fixing is used for these engaging portions. In addition to the position described above, the external force relaxation support portion 21 may exist at a location where the support member 15 and the drive shaft 11 face each other, and the other end of the piezoelectric element 18 and the stationary portion 13. It may exist in both of the places where the support member 15 and the drive shaft 11 face each other. In addition, it is preferable that the location which provides the external force relaxation support part 21 is one place from a viewpoint of reducing the complexity of the structure of a drive device, or a viewpoint of size reduction of a drive device. Since the gravity center position of the drive unit 200 is biased toward the stationary part 13, the arrangement of the external force relaxation support unit 21 is, for example, from the viewpoint of relaxing the influence of external force in consideration of the gravity center position. It is preferably between the other end of the element 18 and the stationary part 13.

As described above, the external force relaxation support unit 21 engages the driving unit 200 with the casing 31, supports the driving unit 200 with respect to the stationary unit 13 of the casing 31, and connects the driving unit 200 to the driving unit 200. Reduce the influence of external forces. In this embodiment, since it becomes an inexpensive and simple structure, the external force relaxation support part 21 is a spring (support spring 21), for example. From the above, the support spring 21 engages the drive unit 200 with the housing 31, supports the drive unit 200 with respect to the stationary unit 13 of the housing 31, and reduces the influence of external force on the drive unit 200. .

The support spring 21 only needs to have a structure that reduces the influence of the external force when it receives an external force in a direction different from the axial direction. For example, the support spring 21 is a spring densely wound in a coil shape (closely wound spring), a leaf spring, or the like. The material of the spring is any material such as metal, resin, and carbon.

Arbitrary densely wound springs are used as the support springs 21, but below, a tension spring (densely wound spring) wound in a coil shape is used.

Spring is roughly divided into two types: compression coil springs and tension springs. A compression coil spring is a spring that is wound in a coil shape (cylindrical shape), with a gap between each line, and the length of the spring shrinks in the load direction by applying a pressing force to both ends of the spring. Arise. The tension spring is a spring in which the length of the spring extends in the load direction by applying a pulling force to both ends of the spring without any gap between the coils wound in a coil shape, and generates a force in the contracting direction.

The densely wound pulling spring is preferably a spring in which a so-called initial tension is generated between the coil wires in contact with each other, for example, depending on the process of forming the tensioning spring into a densely wound shape. A tension spring having an initial tension does not change its length in the load direction unless a predetermined tensile load is applied to the spring, and this predetermined load force is called an initial tension. This initial tension is said to be generated, for example, in the coil forming process because it is wound at a pitch shorter than the diameter of the coil wire. For example, the initial tension is formed so that the coils are in close contact with each other under no load. It is also said that this occurs because the coil wire is twisted so that the coils are in close contact with each other. In addition, the dimension and material of a close winding spring are suitably selected according to the dimension of the piezoelectric element 18 or a drive device, the resistance to an external force, and a restoring force.

Since the cylindrical coiled tightly wound spring is a tension spring, the length of the spring does not change due to the pushing force in the direction of the spring's generatrix (cylinder axial direction), while it has an initial tension in the generatrix direction. Therefore, the length of the spring does not change unless the pulling force in the direction of the generatrix of the spring is equal to or greater than a predetermined force (initial tension). Therefore, in the present embodiment, the support spring 21 does not expand and contract with respect to the generatrix direction with the degree of expansion and contraction of the piezoelectric element 18 with respect to the generatrix direction of the spring.

When a cylindrical coiled densely wound spring is subjected to an external force in a direction perpendicular to the generatrix direction, the shape of the cylinder is a cylinder shape (oblique angle) where the angle between the cylinder generatrix and the cylinder bottom is not orthogonal. The columnar shape) causes distortion, and the distortion generates a drag force and a restoring force against the external force in the densely wound spring, and can absorb an external force in a direction perpendicular to the direction of the generatrix of the spring. As described above, the support spring 21 that is a close winding spring receives the external force in the direction orthogonal to the generatrix direction of the spring, that is, the external force in the direction different from the one direction (axial direction). The influence of the external force on the drive unit 200 can be absorbed and mitigated.

FIG. 4A shows a side view and a front view of the densely wound spring of this embodiment, and FIG. 4B shows a side view of the support spring 21 using the densely wound spring. FIG. 4A shows a cylindrical tightly wound spring wound in a coil shape with no gap between the lines. When the piezoelectric element 18 is substantially cylindrical and its diameter is slightly smaller than the inner diameter of the spring, as shown in FIG. 4B, the end of the piezoelectric element 18 of the drive unit 200 is fitted into the inner diameter portion of the densely wound spring. The support spring 21 can be easily manufactured. In this way, the end of the drive unit 200 on the close winding spring side (coil spring side) is fitted into the inner diameter part of the close winding spring, whereby the close winding spring (external force relaxation support unit) and the drive unit 200 Can be easily combined. The close winding spring 21 and the piezoelectric element 18 are bonded and fixed, for example, and the close winding spring 21 and the boss 13a of the housing 31 (stationary portion 13) are bonded and fixed, for example.

Next, another aspect of the support spring 21 will be described. A case where a leaf spring is used as the support spring 21 will be described. FIG. 4C shows a side view and a front view of the leaf spring of this embodiment, and FIGS. 4D and 4E show a side view of the support spring 21 using the leaf spring.

The support spring 21 may be an arbitrary leaf spring. In the following, a thin leaf spring having a structure having at least two planar portions is used as the leaf spring. One plane portion is engaged with the casing 31 (stationary portion 13), and the other plane portion is engaged with the drive unit 200. More specifically, as shown in FIG. 4C, the leaf spring has a substantially L-shaped cross section composed of two rectangular plates connected at right angles. The two rectangular plates connected to each other have substantially the same thickness and width, but have different lengths. The shorter one of the two rectangular plates is referred to as a foot plate, and the longer one is referred to as a trunk plate. The support spring 21 which is a leaf spring is formed by a pair of the above substantially L-shaped leaf springs, and is disposed so that the body plates face each other. The drive unit 200 is sandwiched between the mutually opposing body plates. The shape of the leaf spring depends on the shape of the piezoelectric element 18 to be bonded and fixed, the magnitude of the external force applied to the driving unit 200 including the piezoelectric element 18, and the like, and is not limited to the L shape. Further, the length, thickness, and width dimensions of the leaf springs, or the material of the leaf springs are appropriately selected according to the dimensions of the driving device, the resistance against external force, and the restoring force. The support spring 21, which is a leaf spring, comes into contact with the boss 13 a protruding from the stationary portion 13 at the base end on the foot plate side, and each body plate portion is bonded and fixed to, for example, the piezoelectric element 18 of the driving portion 200. .

FIG. 4C shows a pair of substantially L-shaped leaf springs. When the piezoelectric element 18 has two parallel planes such as a substantially rectangular parallelepiped shape, the distance between the body plates is adjusted as shown in FIG. 4D so that each body plate is in contact with each plane. Thus, the piezoelectric element 18 can be fitted into the space portion of the pair of body plates facing each other. The pair of leaf spring support springs 21 and the piezoelectric element 18 are, for example, bonded and fixed, and the pair of leaf spring support springs 21 and the boss 13a of the casing 31 (stationary portion 13) are, for example, bonded and fixed. .

In such a configuration, the L-shaped angle formed by the body plate portion and the foot plate portion is substantially a right angle in a normal state. When an external force in a direction orthogonal to the axial direction is applied to the drive unit 200, the support force 21 of the pair of leaf springs is loaded with an external force in a direction orthogonal to the body plate portion. When the external force in the orthogonal direction is applied to the body plate portion, one of the pair of leaf springs is distorted so that the angle exceeds 90 degrees, and the angle becomes less than 90 degrees. Thus, the other is distorted, so that a drag force and a restoring force against the external force are generated in the leaf spring, and the influence of the external force can be absorbed.

In the state of FIG. 4D, when an external force P is applied to the drive unit 200 in a direction orthogonal to the axial direction, one of the pair of leaf springs is pressed by the external force P as shown in FIG. 4E. Is distorted so that the angle formed between the trunk plate portion and the foot plate portion exceeds 90 degrees, and the other is less than 90 degrees because the angle formed between the trunk plate portion and the foot plate portion is pushed by an external force. As a result, the plate spring 21 generates a drag force and a restoring force against the external force applied to the drive unit 200, and the support springs 21 of the pair of plate springs can absorb the external force. Therefore, the support spring 21 composed of a pair of substantially L-shaped leaf springs is supported when the drive unit 200 receives the external force P, that is, an external force in a direction different from the one direction (or the axial direction). By applying an external force P in a vertical direction to each body plate portion of the spring 21, the influence of the external force on the drive unit 200 can be absorbed and mitigated.

Hereafter, returning to the initial mode, the description will be made assuming that the support spring 21 is a tightly wound tension spring (dense tension spring) having an initial tension.

As shown in FIG. 1, the drive shaft 11 included in the drive device has a length equal to or greater than the amount of displacement by which the lens holding frame 12 moves, and the drive unit to which the piezoelectric element 18 and the drive shaft 11 are fixed. The shape 200 is elongated in the axial direction. Therefore, when the support spring 21 of the external force relaxation support portion does not exist and each of the housing 31, the piezoelectric element 18, and the drive shaft 11 is bonded and fixed, an external force in a direction different from the axial direction due to a drop impact or the like. Is applied to the driving device 100, the driving device is relatively weak to bending stress generated by an external force, and there is a possibility that the adhesion and fixing portions thereof are damaged. In addition, the drive shaft 11 that is elongated in the axial direction and the piezoelectric element 18 that is laminated in the axial direction are relatively weak to such bending stress and may be damaged. However, the drive device 100 of this embodiment includes the support spring 21 that reduces the influence of the external force on the drive unit 200 when the external force is received. With such a configuration, it is possible to reduce damage to the driving device due to bending stress generated by the external force.

This point will be described with reference to FIG. FIG. 5A shows a state where the support spring 21 and the drive unit 200 are stationary. In FIG. 5, the drive unit 200 is arranged so that the axial direction is orthogonal to the direction of gravity, and the illustration of the slider block 12a, the lens holding frame 12, the lens L1, and the like is omitted. This also applies to FIG. 7 described later. Since the support spring 21 is a tightly wound spring and has an initial tension, in FIG. 5, the drive unit 200 (the drive shaft 11 and the piezoelectric element 18 in the example shown in FIG. 5) hangs down in the direction of gravity (horizontal). There is no inclination in the weight direction with respect to the direction), and the spring does not expand or contract in the axial direction. In FIG. 5, an xy orthogonal coordinate system is set in which the horizontal direction is the x direction and the gravity direction is the -y direction.

FIG. 5B shows a case where the driving unit 200 receives an external force in a direction different from the axial direction due to an impact or the like by which the driving device 100 is dropped. FIG. 5B shows, as an example, a case where the casing 31 falls and receives an external force P in a direction (gravity direction, −y direction) perpendicular to the horizontal axial direction. The drive part 200 is pulled by the external force P in the acting direction of the external force P. That is, since the support spring 21 which is a close winding spring has a so-called initial tension, it does not substantially absorb external force in the axial direction, and the gravity direction is different from the axial direction, that is, the horizontal axial direction. The winding spring is distorted in the direction perpendicular to the direction. The boss 13a may be elastically deformed in accordance with the deformation generated in the support spring 21 to which the external force P is applied. By pulling the drive unit 200 in the direction in which the external force P is applied, the influence of the external force on the drive unit 200 is absorbed as elastic energy, and the influence of the external force is alleviated.

As described above, the driving device 100 according to the present embodiment includes the support spring 21 having one end engaged with the other end of the piezoelectric element 18 and the other end engaged with the stationary portion 13. When an external force in a direction different from the axial direction is received due to a drop impact or the like of the drive device 100, damage to the drive device due to bending stress generated by the external force can be reduced.

In the driving device 100 of the present embodiment, the support spring 21 is not displaced in the expansion / contraction direction when a driving force is generated, but is displaced in a direction intersecting with the expansion / contraction direction when receiving an external force. For this reason, the external force relaxation support portion 21 can absorb and relax the influence of the external force on the drive unit 200 without affecting the expansion and contraction motion of the piezoelectric element 18.

[Embodiment 2]
This will be described with reference to FIG. Similar to the first embodiment, the drive device 100 ′ of the second embodiment includes at least the drive shaft 11 and the piezoelectric element 18 as a plurality of members included in the drive unit 200. Similarly to the first embodiment, the driving device 100 ′ further includes a lens L 1, a lens holding frame 12, an external force relaxation support portion 21, a casing 31, and a driving circuit 30. The drive device 100 ′ according to the present embodiment further includes a base body 19 that is a weight, which is different from the first embodiment. The base body 19 is included in a plurality of members included in the drive unit 200. Below, it demonstrates centering on this different point.

The base 19 is interposed between the piezoelectric element 18 and the support spring 21. In the present embodiment, one end of the base 19 and the other end of the piezoelectric element 18 are fixed, and the other end of the base 19 and one end of the support spring 21 are connected. More specifically, the end surface of one end of the base 19 and the other end of the piezoelectric element 18 are bonded and fixed, and the peripheral surface of the other end of the base 19 and one end of the support spring 21 are bonded and fixed. When viewed from the support spring 21, one end thereof is bonded and fixed to the peripheral surface of the other end of the base 19, and the other end is bonded and fixed to the stationary portion 13. When the outer shape of the base body 19 is a substantially cylindrical shape, the support spring 21 is a coiled (cylindrical) winding spring, so the diameter of the core portion of the support spring 21 with respect to the diameter of the column of the base body 19. Is slightly larger, the base body 19 can be fitted inside the support spring 21 (inner diameter side), and the support spring 21 can be easily manufactured. Even in this case, after the fitting, the support spring 21 and the base body 19 may be fixed by adhesive fixing or the like.

The piezoelectric element 18 is supported on the base 19 by being bonded and fixed to the base 19. By providing the base body 19 that is a weight, the vibration displacement of the piezoelectric element 18 is efficiently transmitted to the drive shaft 11, and the piezoelectric element 18 can move the lens holding frame 12 efficiently. That is, when the mass of the base body 19 is M and the total mass of the drive shaft 11, the lens holding frame 12 and the lens L1 is m, the displacement amount X on the base body 19 side relative to the piezoelectric element 18 and the drive shaft according to the momentum conservation law. This is because the ratio of the displacement amount x on the 11th side is substantially “X: x = m: M”, and therefore, when the mass M is larger than the mass m, the displacement amount x becomes larger than the displacement amount X. Note that the mass of the housing 31 may be added to the mass M. In the present embodiment, the support spring 21 is a tightly wound spring having an initial tension, and as described above, the support spring 21 is in the direction of the bus bar in the extent of the expansion and contraction force of the piezoelectric element 18 with respect to the bus bar direction of the spring. Since it does not expand and contract, the casing 31 and the base body 19 can be handled as a unit in the axial direction, and the mass M can be the sum of the mass of the base body 19 and the mass of the casing 31.

Since the base body 19 is added, these shapes formed by bonding the base body 19, the piezoelectric element 18, and the drive shaft 11 become more elongated in the axial direction. In addition, when there is no external force relaxation support portion between the stationary portion 13 and the base body 19 as in the prior art, the weight member is added, so that the gravity portion from the driving portion 200 with respect to the stationary portion 13 is separated. The force is larger than that in the first embodiment. For this reason, when the driving unit 200 receives an external force in a direction different from the axial direction due to a drop impact of the driving device 100 ′, the adhesion between the base body 19 and the stationary unit 13 is easily broken.

However, the drive device 100 ′ of the present embodiment includes the support spring 21 that reduces the influence of the external force on the drive unit 200 when receiving the external force. For this reason, even if the base 19 is added, the support spring 21 can absorb the influence of external force. Therefore, similarly to the first embodiment, it is possible to reduce the damage to the drive device due to the bending stress generated by the external force.

This point will be described with reference to FIG. FIG. 7A shows a state where the drive unit 200 including the support spring 21 and the base body 19 is stationary. Since the support spring 21 is a so-called densely wound spring and has an initial tension, the drive unit 200 (the drive shaft 11 and the piezoelectric element 18 in the example shown in FIG. 7) does not sag in the gravity direction in FIG. The spring is not expanded or contracted with respect to the axial direction.

FIG. 7B shows a case where the driving unit 200 receives an external force in a direction different from the axial direction (x direction) due to an impact or the like by which the driving device 100 ′ is dropped. FIG. 7B shows a case where the casing 31 falls as an example and receives an external force P in a direction orthogonal to the horizontal axial direction (gravity direction, −y direction). The drive part 200 is pulled by the external force P in the acting direction of the external force P. That is, since the support spring 21 which is a close winding spring has a so-called initial tension, it does not substantially absorb external force in the axial direction, and the gravity direction is different from the axial direction, that is, the horizontal axial direction. The winding spring is distorted in the direction perpendicular to the direction. By pulling the drive unit 200 in the direction in which the external force P is applied, the influence of the external force on the drive unit 200 is absorbed as elastic energy, and the influence of the external force is alleviated.

As described above, the driving device 100 ′ of the present embodiment includes the support spring 21 having one end engaged with the other end of the base body 19 and the other end engaged with the stationary portion 13. The lens holding frame 12 can be efficiently moved, and further includes a base body 19 which is an example of a weight member when an external force in a direction different from the axial direction is received due to a drop impact of the driving device 100 ′. Further, it is possible to reduce the damage to the drive device due to the bending stress generated by the external force.

[Embodiment 3]
This will be described with reference to FIG. Similarly to the second embodiment, the drive device 100 ″ of the third embodiment includes at least the drive shaft 11, the piezoelectric element 18, and the base body 19 as a plurality of members included in the drive unit 200. Also, the drive device 100. As in the second embodiment, “” further includes a lens L 1, a lens holding frame 12, an external force relaxation support portion 21, a housing 31, and a drive circuit 30. The drive device 100 ″ of this embodiment further includes a reinforcing member 20 that reinforces the engaging portion between the piezoelectric element 18 and the drive shaft 11, and this point is different from the second embodiment. In the following, different points will be mainly described.

An engagement portion between the piezoelectric element 18 and the drive shaft 11, more specifically, an adhesive fixing portion between the piezoelectric element 18 and the drive shaft 11 is covered with a reinforcing member 20, and the inside (the piezoelectric element 18 and the drive shaft 11 is connected). Between the adhesive fixing part and the reinforcing member 20), the adhesive is fixed by an adhesive such as an epoxy adhesive. The reinforcing member 20 is a member used for the purpose of supporting and reinforcing the piezoelectric element 18 and the drive shaft 11 so that the adhesive fixing portion between the piezoelectric element 18 and the drive shaft 11 is not damaged. The reinforcing member 20 is a member used for the purpose of dispersing and absorbing the force applied to the adhesive fixing portion or for preventing moisture from entering the adhesive fixing portion.

FIG. 9A shows a state before assembling the piezoelectric element 18 and the drive shaft 11 that are adhesively fixed with the reinforcing member 20 placed on the adhesive fixing portion, and FIG. 9B shows a state after the assembling. The reinforcing member 20 is fitted into the adhesive fixing portion between the piezoelectric element 18 and the drive shaft 11 and the inside thereof is filled with an adhesive, and the piezoelectric element 18, the driving shaft 11 and the reinforcing member 20 are integrally bonded and fixed. Thereby, since the area bonded by the adhesive is increased, the piezoelectric element 18 and the drive shaft 11 can be firmly bonded and fixed. The adhesive may be not only an epoxy adhesive but also, for example, a cyanoacrylate adhesive or the like. The material of the reinforcing member 20 is metal, plastics, hard rubber or the like.

The reinforcing member 20 may have various shapes from the viewpoints of increasing the adhesive strength, preventing moisture from entering, and improving the elasticity of the reinforcing member itself. In the present embodiment, the reinforcing member 20 has the following shape. In FIG. 9, the piezoelectric element 18 has a substantially rectangular parallelepiped shape in which each laminated surface is substantially square when viewed from the axial direction, and the drive shaft 11 has an elongated substantially cylindrical shape whose cross section is substantially circular when viewed from the axial direction. is there. The reinforcing member 20 has a shape that can be fitted into both the piezoelectric element 18 and the drive shaft 11 in order to cover the adhesive fixing portion between the piezoelectric element 18 and the drive shaft 11. In FIG. 9, the reinforcing member 20 has a substantially cylindrical portion with a substantially circular cross section for fitting one end of the drive shaft 11 and a substantially square cross section for fitting one end of the piezoelectric element 18. A rectangular tube-shaped portion. The reinforcing member 20 is composed of, for example, a single component, and two differently shaped portions, that is, a substantially cylindrical portion and a rectangular tube-shaped portion, exist in the single component. The substantially cylindrical portion has a substantially circular hole that is opened through so that the drive shaft 11 can be inserted therein. The diameter of the hole is slightly larger than the diameter of the circular shape that is a cross section in a direction perpendicular to the generatrix of the drive shaft 11 having a substantially cylindrical shape. On the other hand, the rectangular tube-shaped portion has a substantially square hole that is opened through so that the piezoelectric element 18 can be inserted therein. The shape and size of the hole is a shape and size corresponding to the cross section perpendicular to the axial direction of the piezoelectric element 18, that is, the shape and size of the hole is slightly larger than the cross section of the piezoelectric element 18. large. The cross section in the direction perpendicular to the axis of the piezoelectric element 18 has a square shape. Between the substantially cylindrical portion and the rectangular tube-shaped portion, one end portion of the substantially cylindrical portion and one end portion of the rectangular tube-shaped portion are connected, from the substantially cylindrical portion toward the rectangular tube-shaped portion. It is connected so that the shape changes gently.

The reinforcing member 20 can be inserted from the drive shaft 11 side toward the piezoelectric element 18 at the time of assembly so that the relationship between the circle area and the square area is “the area of the circle <the area of the square”. It is in. Therefore, in the assembly process, the reinforcing member 20 is inserted from the drive shaft 11 side toward the piezoelectric element 18, and the reinforcing member 20 is removed from the drive shaft 11 side without removing the reinforcing member 20 between the piezoelectric element 18 and the drive shaft 11. Assembling is performed while staying at the adhesive fixing part. In the state where the reinforcing member 20 is fastened to the adhesive fixing portion between the piezoelectric element 18 and the drive shaft 11, an adhesive is filled in the reinforcing member 20, that is, between the reinforcing member 20 and the adhesive fixing portion. Therefore, the adhesive fixing portion between the piezoelectric element 18 and the drive shaft 11 is covered with the reinforcing member 20 and is adhesively fixed.

As described above, the driving device 100 ″ according to the present embodiment includes the support spring 21 so that when an external force in a direction different from the axial direction is received due to a drop impact of the housing 31 or the like, an external force is applied to the drive unit 200. The drive device 100 ″ according to the present embodiment includes the reinforcing member 20 so that the piezoelectric element 18 is bent by the bending stress. It is also possible to reduce the damage of the adhesive fixing portion between the drive shaft 11 and the drive shaft 11. Furthermore, the drive device 100 ″ of the present embodiment can further reduce the breakage of the adhesive fixing portion by filling the inside covered with the reinforcing member 20 with the adhesive. The drive device 100 ″ of the present embodiment can also be reduced. By providing the reinforcing member 20, it is possible to prevent moisture from entering the bonded portion between the piezoelectric element 18 and the drive shaft 11 and to provide reliable reinforcement against long-term driving and deterioration. .

[Embodiment 4]
This will be described with reference to FIG. The apparatus according to the present embodiment is an imaging apparatus IM including any one of the driving apparatuses according to the first to third embodiments. Hereinafter, as a representative example, the imaging device IM including the driving device 100 ″ of the third embodiment will be described. The imaging device IM of the present embodiment includes the driving device 100 ″ of the third embodiment and the imaging element 80. . As described above, the drive device 100 ″ includes at least the drive shaft 11, the piezoelectric element 18, and the base body 19 as a plurality of members included in the drive unit 200, and further includes the lens L1, the lens holding frame 12, and the like. The external force relaxation support portion 21, the reinforcing member 20, the casing 31, and the drive circuit 30. The imaging device IM of the present embodiment further includes an imaging element 80 in such a driving device 100 ″. This point is different from the third embodiment. Below, it demonstrates centering on this different point. Note that the imaging apparatus including the driving device 100 according to the first embodiment does not include the base 19 and the reinforcing member 20, and the imaging apparatus including the driving device 100 ′ according to the second embodiment is different from the example illustrated in FIG. In contrast to the example shown in FIG.

The image sensor 80 is an element that converts received light into an electrical signal. The imaging element 80 includes an object (subject) formed on the light receiving surface of the imaging element 80 through the one or more optical elements by an imaging optical system (not shown) that includes one or more optical elements. Is an element that photoelectrically converts the optical image into image signals of R (red), G (green), and B (blue) components according to the amount of light and outputs the image signals to a predetermined image processing circuit (not shown). . The image sensor 80 is, for example, a CCD image sensor, a CMOS image sensor, or the like. An image processing circuit (not shown) performs amplification processing, digital conversion processing, and the like on the analog image signal input from the image sensor 80, and further determines an appropriate black level, γ correction, and white for the entire image. Image data is generated from the image signal by performing known image processing such as balance adjustment (WB adjustment), contour correction, and color unevenness correction.

The above-described lens L1 attached to and held by the lens holding frame 12 is an optical element that moves along the optical axis 81 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 81 to perform focusing (focusing), and, for example, a lens that moves along the optical axis 81 to perform zooming (magnification). It may be. The optical image of the object is guided along the optical axis 81 to the light receiving surface of the image sensor 80 by the image pickup optical system including the lens L1 and is picked up by the image sensor 80. The optical axis 81 of the lens L1 is indicated by a one-dot chain line 81 in FIG. 10, and the optical axis 81 and the axial direction (a direction) are parallel to each other.

Since such an imaging device IM includes any one of the above-described driving devices including the above-described external force relaxation support portion (support spring 21), the imaging device IM receives an external force in a direction different from the one direction (axial direction). In this case, the influence of the external force on the drive device can be reduced, and the damage to the drive device due to the bending stress generated by the external force can be reduced. Therefore, the imaging device IM can improve impact resistance in the case of dropping.

As a modification of the above-described first to fourth embodiments, for example, in the first to fourth embodiments described above, the slider block 12a is formed in the extended portion of the lens holding frame 12, but is different from the lens holding frame 12. It may be formed on the body. In such a case, the lens holding frame 12 is further formed with a through hole for inserting a guide rod for guiding the movement of the lens holding frame 12. The slider block 12a is further formed with a recess for sandwiching the lens holding frame 12. When the lens holding frame 12 is sandwiched in the concave portion of the slider block 12a, the lens holding frame 12 also moves as the slider block 12a moves. By forming the slider block 12a separately from the lens holding frame 12 in this way, vibration transmitted from the slider block 12a to the lens holding frame 12 is reduced, and the optical axis shift of the lens holding frame 12 can be reduced. From this viewpoint, it is preferable that an elastic member such as rubber is interposed between the concave portion of the slider block 12a and the lens holding frame 12 in order to absorb vibration.

Further, in each of the first to fourth embodiments described above, the external force relaxation support portion 21 is fitted into the boss 13a that protrudes outward from the surface of the stationary portion 13 along the axial direction a and is adhered to the boss 13a. It may be fitted into a concave portion that is recessed inward from the surface of the portion 13 along the axial direction a.

This specification discloses various modes of technology as described above, and the main technologies are summarized below.

The driving device according to one aspect is fixed to one end of the electromechanical conversion element in an expansion / contraction direction of the electromechanical conversion element that converts applied electric energy into an expansion / contraction motion (mechanical energy to expand / contract), and the expansion / contraction direction A drive member that is movably supported by the drive unit, and generates a predetermined drive force, and supports the drive unit with respect to the fixed member, and the drive unit has an external force in a direction different from the expansion / contraction direction. An external force relaxation support portion that relaxes the influence of the external force on the drive portion, and an engagement member that is frictionally engaged with the drive member with a predetermined friction force. The portion exists between the other end of the electromechanical conversion element with respect to the expansion / contraction direction and the fixing member, and supports the drive unit from the expansion / contraction direction.

In such a drive device, since the external force relaxation support portion is provided, the influence of the external force on the drive portion is reduced by absorbing the external force to be applied to the drive portion by the external force relaxation support portion. . For this reason, according to this structure, the drive device using the electromechanical transducer which can reduce the damage by the bending stress generated by the external force is provided.

In another aspect, in the above-described driving device, the external force relaxation support portion is not displaced in the expansion / contraction direction when the driving force is generated, but is displaced in a direction intersecting the expansion / contraction direction when receiving the external force. It is preferable.

According to this configuration, the external force relaxation support portion can absorb and relax the influence of the external force on the drive unit without affecting the expansion and contraction motion of the electromechanical transducer.

In another aspect, in the above-described driving device, the driving unit is disposed between the electromechanical conversion element and the external force relaxation support unit, and is fixed to the electromechanical conversion element and the external force relaxation support unit. A weight portion may be further provided.

By further providing the weight portion, the electromechanical conversion element can drive the drive member efficiently, while the bending stress generated by an external force becomes larger than when the drive portion does not include the weight portion. However, since the drive device includes the external force relaxation support portion, the external force to be applied to the drive portion can be absorbed by the external force relaxation support portion, thereby reducing the influence of the external force on the drive portion. For this reason, even when the drive part has a weight part, it is possible to reduce the damage to the drive device due to the bending stress generated by the external force.

In another aspect, the above-described driving device may further include a reinforcing member that covers a fixed portion between the electromechanical conversion element and the driving member.

Such a driving device reinforces the fixing portion of the electromechanical conversion element and the driving member with a reinforcing member, so that the damage to the driving device due to bending stress generated by an external force can be further reduced.

And the above-mentioned external force relaxation support part may be any one of the following aspects. For example, the external force relaxation support portion may be a spring having an initial tension. Further, for example, the external force relaxation support part may be a coiled coil spring. For example, the external force relaxation support portion may be a leaf spring.

Such a drive device including the external force relaxation support portion of each aspect has a low-cost and simple configuration by using a spring having initial tension, a closely wound coil spring, and a leaf spring as the external force relaxation support portion. . Further, in each of these aspects, only the influence of an external force in a direction different from the expansion / contraction direction is preferably alleviated, and the absorption of the external force in the direction of the expansion / contraction direction itself is small. For this reason, such a drive device can reduce the damage of the drive device due to the bending stress generated by the external force, and normally has a low possibility of absorbing the expansion and contraction of the electromechanical conversion element. The expansion and contraction of the mechanical conversion element can be transmitted to the drive member more reliably.

In another aspect, in the drive device in which the external force relaxation support portion is a coil spring, the end portion on the coil spring side of the drive portion is preferably fitted into an inner diameter portion of the coil spring. .

Such a drive device can easily couple the external force relaxation support portion and the drive portion.

An imaging apparatus according to another aspect includes any one of the above-described driving apparatuses, an imaging element that converts received light (an optical image of an object) into an electric signal, and one or a plurality of optical elements. Or an imaging optical system that forms an optical image of an object on a light receiving surface of the imaging element through a plurality of optical elements, and moves along the optical axis direction of the one or more optical elements in the imaging optical system The optical element is attached to the engaging member of the driving device.

Since such an imaging apparatus includes the external force relaxation support portion, the influence of the external force on the drive portion is reduced by absorbing the external force to be applied to the drive portion with the external force relaxation support portion. . For this reason, such an imaging apparatus can reduce damage due to bending stress generated by the external force. Therefore, such an imaging apparatus can improve the impact resistance in the case of dropping.

This application is based on Japanese Patent Application No. 2012-271093 filed on December 12, 2012, the contents of which are included in this application.

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

According to the present invention, it is possible to provide a drive device using an electromechanical transducer and an imaging device using the drive device.

Claims

An electromechanical transducer that converts electrical energy into telescopic motion;
A driving member that generates a predetermined driving force, and includes a driving member that is fixed to one end of the electromechanical conversion element in the expansion / contraction direction and is supported to be movable in the expansion / contraction direction;
An external force relaxation support unit that supports the drive unit with respect to a fixed member, and reduces the influence of the external force on the drive unit when the drive unit receives an external force in a direction different from the expansion and contraction direction;
An engagement member frictionally engaged with the drive member with a predetermined friction force,
The external force relaxation support portion is disposed between the other end of the electromechanical conversion element with respect to the expansion / contraction direction and the fixing member, and supports the driving unit from the expansion / contraction direction.
Drive device.
The external force relaxation support portion is not displaced in the expansion / contraction direction when the driving force is generated, and is displaced in a direction intersecting the expansion / contraction direction when receiving the external force,
The drive device according to claim 1.
The drive unit further includes a weight part that is disposed between the electromechanical conversion element and the external force relaxation support part, and is fixed to the electromechanical conversion element and the external force relaxation support part.
The drive device according to claim 1 or 2.
A reinforcing member that covers a fixed portion of the electromechanical transducer and the driving member;
The drive device according to any one of claims 1 to 3.
The external force relaxation support portion is a spring having an initial tension.
The drive device according to any one of claims 2 to 4.
The external force relaxation support portion is a closely wound coil spring.
The drive device according to claim 5.
The coil spring side end of the drive unit is fitted into the inner diameter of the coil spring.
The drive device according to claim 6.
The external force relaxation support portion is a leaf spring.
The drive device according to any one of claims 2 to 4.
A driving device according to any one of claims 1 to 8,
An image sensor that converts received light 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;
The optical element that moves in the optical axis direction among the one or more optical elements in the imaging optical system is attached to the engagement member of the drive device.
Imaging device.