JPH07264886A - Piezoelectric actuator - Google Patents

Abstract

PURPOSE:To provide a piezoelectric actuator which has a small size, can be improved in durability against impacts, and can be applied to low-invasion high-performance medical instruments and optical equipment. CONSTITUTION:In a piezoelectric actuator provided with a stationary member 1, mobile body 2 which is frictionally coupled with the member 1 in a slidable state, and piezoelectric element 3 which is expanded or contracted in the axial direction when a driving voltage is applied across the body 2 and, at the same time, one end section of which is connected with the body 2, the element 3 is provided at a position where the element 3 is included in the external size of the element 3 in at least one direction perpendicular to the axial direction of the element 3. Therefore, the size of the actuator can be reduced and the durability of the actuator against impacts can be improved, because the element 3 is housed within the external size area of the body 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small piezoelectric actuator for moving a moving body by an impact force utilizing expansion and contraction of a piezoelectric (including electrostrictive) element.

[0002]

2. Description of the Related Art A piezoelectric actuator is known which comprises a piezoelectric element, a movable body fixed to one end of the piezoelectric element, and a stationary member slidably frictionally engaged with the movable body (Japanese Patent Laid-Open No. Hei 4). -177214). The piezoelectric element is attached so as to protrude from the moving body in one direction.

[0003]

However, in such a structure, the moving body and the piezoelectric element are connected in series, the piezoelectric element is long in the axial direction, and the piezoelectric element largely protrudes from the outer region of the moving body. Therefore, the size of the entire piezoelectric actuator device becomes considerably large, and it is not easy to compactly incorporate it into a medical device, an optical device, or the like.

When the piezoelectric actuator receives an external impact, the piezoelectric element is deformed, and the piezoelectric element directly collides with a stationary member or a member of a device to be incorporated, and the piezoelectric element is There was a risk of breakage, and there was a problem with impact resistance.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to reduce the size of the piezoelectric actuator and improve the durability against impact, which is low in invasiveness and high in performance. It is to provide a piezoelectric actuator that can be applied to medical devices and optical devices.

[0006]

According to the present invention, a stationary member, a movable body slidably frictionally engaged with the stationary member, and a driving voltage are applied thereto to expand and contract in the axial direction. And a piezoelectric element having one end portion in the axial direction connected to the moving body, a position included in the outer shape of the moving body in at least one direction in a direction perpendicular to the axial direction of the piezoelectric element. The piezoelectric element was arranged in the. Therefore, the piezoelectric element is housed in the outer region of the moving body, the piezoelectric actuator is downsized, and the durability against impact is enhanced.

[0007]

【Example】

(First Embodiment) This first embodiment will be described with reference to FIGS. The stationary member 1, the moving body 2, and the piezoelectric element 3 are the basic members of the piezoelectric actuator in this embodiment. As the stationary member 1, a straight tubular stainless steel circular tube 4 as shown in FIG. 1A is used, and the moving body 2 is fitted into the circular tube 4 to attach the moving body 2 to the circular tube 4. Slidably frictionally engaged. This moving body 2 has a base 5
And a pair of elastic beams (which may be referred to as legs) 6 which are made of an integral member made of aluminum. As shown in FIGS. 1B and 1C, the base 5
A pair of projecting portions 7 that come into contact with the inner surface of the circular pipe 4 are formed on the outer side surface portions of the projecting tips of the pair of beams 6 projecting in substantially the same direction. That is, the moving body 2 has the pair of beams 6,
The projecting portion 7 is frictionally engaged with the inner surface of the circular tube 4 by the urging force expanded by its own elastic force.

As shown in FIGS. 1B and 1C, the piezoelectric element 3 is composed of a rectangular parallelepiped plate-shaped laminated piezoelectric element laminated in the direction of the central axis of the circular tube 4. The longitudinal direction is arranged along the central axis of the circular pipe 4 at the center of the space defined by the beams 6. Further, the beams 6 are positioned so as to face each other in the plate thickness direction smaller than the plate (horizontal) width of the piezoelectric element 3. As shown in FIG. 1C, in this embodiment, the plate width of the piezoelectric element 3 is slightly larger than the width of the beam 6, but the plate width of the piezoelectric element 3 may be smaller than the width of the beam 6. . In any of these cases, the piezoelectric element 3 is arranged in a region substantially included in the outer shape of the moving body 2 in a direction perpendicular to the moving direction of the moving body 2. .

Further, one end of the piezoelectric element 3 is adhered and fixed to the base portion 5 of the moving body 2, so that the piezoelectric element 3 is a cantilever type which is easily deformed to the beam 6 side of the moving body 2,
It is supported by the moving body 2.

A lead wire 8 as a power supply member is mechanically and electrically connected to the free end of the piezoelectric element 3 by connecting means such as soldering or adhesion with a conductive paste. The power supply lead wires 8 are respectively connected to portions of both side surfaces facing each other in a direction perpendicular to the plate thickness direction in which the free end portion of the piezoelectric element 3 is easily curved and deformed. That is, the piezoelectric element 3 is provided with the connecting portion of the lead wire 8 as the power feeding member in a portion which does not face the member of the moving body 2 and avoids it. Further, the lead-out portion of the lead wire 8 is provided so as to be parallel to the surface formed by the pair of beams 6,
The size of the connecting portion is controlled so as not to come into contact with the circle circumscribing the moving body 2.

As shown in FIG. 1B, the length of the protruding free end of the piezoelectric element 3 in the moving direction of the actuator is shorter than the protruding length of the beam 6 of the moving body 2. That is, in the moving direction of the moving body 2, the piezoelectric element 3 is arranged in a region included in the outer shape of the moving body 2.

The material of the circular tube 4 may be acrylic or the like, and the material of the moving body 2 may be plastic or the like.

When an external impact is applied to the circular pipe 4 due to a shock or the like when the piezoelectric actuator is dropped and collided, the beam 6 is elastically engaged with the circular pipe 4 and the movement is performed. One beam 6 of the body 2 elastically bends toward the axial center axis side of the circular tube 4 due to its inertia. As a result, the beam 6 acts as a shock absorbing material that absorbs impact. In addition, since the piezoelectric element 3 is shorter as it is included in the outer shape of the moving body 2, the impact force applied to the piezoelectric element 3 is smaller than that in the case where the piezoelectric element 3 largely protrudes from the outer shape of the moving body 2, and the piezoelectric element 3 has a circular shape. Since the tube 4 and other members of the device in which the piezoelectric actuator is incorporated do not directly come into contact with each other and the resistance force against bending (breaking force) increases, the piezoelectric element 3 is less likely to break. The piezoelectric element 3
Is formed in a plate shape, and the beam 6 of the moving body 2 is positioned in the plate thickness direction and is included in the outer shape of the beam. Therefore, when an impact is applied, the piezoelectric element 3 is deformed in the plate thickness direction. However, since the elastic beam 6 of the moving member 2 prevents large deformation, the piezoelectric element 3 is further prevented.

By applying any of the signals having the voltage waveforms shown in FIGS. 2A to 2D to the piezoelectric element 3,
The piezoelectric element 3 has a relationship between the inertial force generated by the impact and the mass of the piezoelectric element 3 itself and the frictional engagement force between the stationary body 1 and the moving body 2 due to the expansion and contraction action of performing rapid deformation and slow recovery. The moving body 2 can be moved in any axial direction. At that time, the connecting portion between the lead wire 8 as the power feeding member and the piezoelectric element 3 is at the installation position and the piezoelectric element 3.
Does not interfere with the leg 6 regardless of the relative length between the moving body 2 and the moving body 2. The lengths of the piezoelectric element 3 and the legs 6 can be arbitrarily set, and a piezoelectric actuator having a short overall length can be provided. Further, the leg 6 and the power feeding member do not interfere with each other, breakage of the power feeding member is avoided, and a piezoelectric actuator having improved durability can be provided. Further, by containing the piezoelectric element in the outer region of the moving body, it is possible to make the device compact, and it is easy to adopt a heat resistance countermeasure or a sterilization countermeasure structure as described later.

(Second Embodiment) This embodiment is shown in FIG.
As shown in (a) and (b), the piezoelectric element 3 has a shape in which it is laminated in a cylindrical shape having an equal diameter over the entire length. The diameter of the cylindrical piezoelectric element 3 is smaller than the width of the beam 6, as shown in FIG. The piezoelectric element 3 is arranged between the pair of beams 6 and in the center of the width thereof. That is, it is included in the outer shape of the moving body 2.

When an external impact is applied to the piezoelectric actuator by dropping or the like, the impact force is also transmitted to the cylindrical piezoelectric element 3, but since the piezoelectric element 3 has a cylindrical shape,
Impacts from all directions have the same effect, eliminating extremely weak parts. Therefore, the transverse rupture force as a whole is increased, and the breakage of the piezoelectric element 3 is reduced when an external impact is applied.

According to this structure, in addition to the effects of the first embodiment described above, it is possible to reduce the diameter and size of the piezoelectric actuator while maintaining durability.

Further, a connecting portion of a lead wire 8 as a power feeding member is formed on the surface of the piezoelectric element 3 which does not face the three legs 6 of the moving body 2, and thus the lead wire 8 does not touch the leg 6. To the rear. Therefore, since there is no interference between the legs 6 of the moving body 2 and the power feeding member, the power feeding member does not break during operation, and the durability is improved.

The piezoelectric element 3 in this embodiment may be replaced with the plate-shaped one in the first embodiment.

(Third Embodiment) As shown in FIGS. 4A and 4B, this embodiment is similar to the above-described second embodiment.
A cylindrical piezoelectric element 3 is formed. Further, the moving body 2
The number of the beams 6 of the above is not three but three. The three beams 6 are arranged at equal intervals of 120 ° in the circumferential direction when viewed from the central axis direction of the circular pipe 4.
The piezoelectric element 3 is arranged at a position included in the outer shape of the moving body 2.

According to this configuration, the above-mentioned first and second
In addition to the effects of the above embodiment, the movable body 2 is provided with three legs 6, which are frictionally engaged with the stationary member 1, so that the posture of the movable body 2 with respect to the stationary member 1 is stable, Smooth movement can be obtained. That is, by the three beams 6,
When the moving body 2 is moved by driving the piezoelectric actuator, tilting of the moving body 2 in the radial direction of the circular tube 4 is suppressed, and the operation of the piezoelectric actuator is stabilized.

(Fourth Embodiment) This embodiment is shown in FIG. This is configured such that the weight 9 as an inertial body of another member is attached to the free end of the piezoelectric element 3 in the configuration of the above-described first embodiment by adhesion or the like, and the inertial body as a separate member is added. Is. The total axial length of the piezoelectric element 3 and the weight 9 is slightly shorter than the length of the moving body 2 in the first embodiment, and the tip position of the weight 9 is smaller than the tip position of the beam 6. It is in the retracted position. The tip of the weight 9 and the tip of the beam 6 may be provided so as to coincide with or slightly protrude from each other. This also means that the piezoelectric element 3 and the weight 9 are arranged at positions included in the outer shape of the moving body 2.

According to this structure, by applying a signal having a voltage waveform as shown in FIGS. 2 (a) to 2 (d) to the piezoelectric element 3, the moving body is moved as in the case of the first embodiment. Two
Can be moved in the axial direction, but in addition to the inertial force of the piezoelectric element 3, the inertial force of the weight 9 is added to increase the impact force. As a result, the moving speed of the piezoelectric actuator itself can be increased and the driving force can be increased. Since the driving speed of the piezoelectric actuator is increased and the driving force is increased, a heavier load can be operated quickly and reliably.

(Fifth Embodiment) This embodiment will be described with reference to FIG. This basic structure is substantially the same as that of the first embodiment described above, but in the structure in which the pair of beams 6 of the moving body 2 are frictionally engaged with the stationary member 1 including the circular pipe 4. The length of the moving body 2 in the moving direction is the same as that of the piezoelectric element 3 or the piezoelectric element 3 is made longer so as to slightly protrude from the tip of the beam 6.
This also includes the piezoelectric element 3 in the outer shape of the moving body 2. The connecting portion of the lead wire 8 is also provided in the same manner as in the case of the first embodiment, but the connecting portion is at a position protruding from the tip of the beam 6 of the moving body 2. However, since this type of piezoelectric actuator is quite small, such as several millimeters to several centimeters, it is important to provide the connecting portion at the same position as in the first embodiment, and in this case, the same merit can be obtained. To be

When an external impact is applied to this piezoelectric actuator, the piezoelectric element 3 bends toward the beam 6 in the moving body 2 as shown in FIG. 6C, but the lead wire 8 of the piezoelectric element 3 is connected. Before the free end side of the moving body 2 hits the inner surface of the circular pipe 4, it hits the beam 6 of the moving body 2.
In this case, since the beam 6 of the moving body 2 has elasticity, the impact force actually received by the piezoelectric element 3 is reduced as compared with the impact force directly applied to the circular tube 4. This makes it difficult for the piezoelectric element 3 to be broken. On the other hand, when the deflected piezoelectric element 3 first collides with the circular tube 4 when an impact is applied, the piezoelectric element 3 receives a large impact, so that the piezoelectric element 3 is easily broken. On the other hand, according to the configuration of the fifth embodiment, the impact force is reduced and the piezoelectric element 3 is hard to break. In addition, the same effects as those of the first embodiment described above can be obtained.

(Sixth Embodiment) As shown in FIG. 7, the basic construction of this embodiment is substantially the same as that of the first embodiment described above, except for the following points. That is,
As shown in FIG. 7A, the length of the beam 6 of the moving body 2 is sufficiently shorter than that of the piezoelectric element 3, and the free end of the piezoelectric element 3 is retracted into the space between the beams 6. It is in. Also,
As shown in FIG. 7B, the lateral width (plate width) of the piezoelectric element 3, that is, the width in the electrode facing direction is shorter than the lateral width of the beam 6 of the moving body 2. If the piezoelectric element 3 is installed within the length and width of the moving body 2 as described above, it becomes easy to take heat resistance measures described later.

The space between the piezoelectric element 3 and the opposing flat surfaces of the pair of beams 6 of the moving body 2 is filled with a heat conductive grease 11 for heat dissipation. This grease 1
A leaf spring 12 is attached and fixed to the front end surface and the left and right end surfaces of the moving body 2 so as to prevent 1 from spilling around. The lead wire 8 is the leaf spring 12
It is led out through a small hole 13 provided in the. The gap of the lead-out portion is, for example, polyparaxylylene (trade name ...
Parylene) is covered and sealed by the seal 14. It also serves as a sterilization resistant structure.

Therefore, when driving the piezoelectric actuator, the piezoelectric actuator can be driven by applying the drive signal having the above-mentioned voltage waveform to the piezoelectric element 3 through the lead wire 8. At this time, generally, the piezoelectric element 3 generates heat, but this heat is conducted from the piezoelectric element 3 to the heat conductive grease 11, and this is conducted to the entire member of the moving body 2 and further to the entire member of the circular tube 4 to generate the piezoelectric element. The heat emitted from the element 3 is radiated to suppress the overheating of the piezoelectric element 3. When the piezoelectric element 3 is overheated, its polarization may disappear, but this can be prevented in this embodiment.

(Seventh Embodiment) As shown in FIG. 8, the moving body 2 in the configuration of the sixth embodiment is cylindrical and slits 21 are provided on both left and right sides thereof. A pair of beams 6 of the moving body 2 which are located above and below.
To form. The gap between the slits 21 is filled and sealed with a rubber adhesive 22.

Also in this case, heat is radiated from the piezoelectric element 3 through the heat transfer path as described above, but the surface area between the moving body 2 and the circular pipe 4 is larger than that in the case of the sixth embodiment. Heat transfer is performed. Therefore, the heat dissipation effect is higher than in the case of the sixth embodiment described above, and the thermal durability of the piezoelectric element 3 is improved.

(Eighth Embodiment) As shown in FIG. 9, in this embodiment, the beam 6 of the moving body 2 is frictionally engaged with the circular tube 4 in the configuration of the first embodiment described above. At
The length of the piezoelectric element 3 in the moving direction of the actuator is shorter than that of the moving body 2, and the lateral width of the piezoelectric element 3, that is, the width in the electrode facing direction is the beam 6 of the moving body 2. Is shorter than the width of the moving body 2
Silicon rubber is press-fitted between the opposing planes of the pair of beams 6 as the shock absorbing member 25, and the beam 6 and the shock absorbing member 2
The contact surfaces with 5 are fixed by adhesion. The shock absorbing member 25 may be the same as the heat conductive grease 11.

According to this structure, when an external impact is applied to the piezoelectric actuator, this impact force is absorbed by the elastic force or viscosity of the impact cushioning member 25, and the impact force applied to the piezoelectric element 3 is reduced. The effect is obtained.

(Ninth Embodiment) This embodiment will be described with reference to FIGS. In this embodiment, the piezoelectric actuator according to the present invention is used for driving a focus adjusting mechanism of an optical system in an electronic endoscope.
FIG. 10 shows a distal end portion 32 of the insertion portion 31 of the electronic endoscope.
11 is a sectional view of the actuator unit 3 for driving the focus adjusting mechanism of the optical system.
3 is shown.

In addition to the image pickup unit 34, the distal end portion 32 has a built-in illumination unit, a channel through which a treatment tool is passed, and an air / water supply tube for cleaning the surface of the observation lens 35 in the image pickup optical system. The image pickup section 34 includes an optical lens group 38, a fixed lens frame 39 that houses the lens group 38, and an image pickup device (CCD) 40. Lens group 3
Part of the lens 41 in 8 is held by a movable frame 42 and is attached to the lens frame 39 slidably in the optical axis direction. The movable frame 42 is moved in the optical axis direction by the actuator unit 33 installed in parallel with the optical axis direction. The movable frame 42 is provided with a connecting arm 43 protruding toward the actuator unit 33 side, and the tip of the connecting arm 43 is slightly different from the shaft 45 protruding in parallel with the optical axis on the moving body 2 of the actuator unit 33. It is connected so as to have a great play.

As the actuator unit 33 here, the piezoelectric actuators of the above-mentioned or later-described embodiments can be applied. FIG. 11 shows a configuration using the piezoelectric actuator described above. The lens frame 39 constitutes the stationary member 1.

When the drive waveform voltage as described above is applied to the piezoelectric element 3, the moving body 2 of the piezoelectric actuator moves in the optical axis direction. The driving force is transmitted to the movable frame 42, which is a lens frame, via the shaft 45,
The movable frame 42 moves in the optical axis direction. Along with this, the lens 41 moves to perform zooming or focusing.

According to this structure, the impact durability of the piezoelectric element 3 in the piezoelectric actuator is improved,
It is possible to obtain an endoscope that is resistant to external impact. Further, by shortening the piezoelectric element 3, the rigid length of the insertion portion 31 of the endoscope can be shortened, the insertability of the endoscope can be improved, and the burden on the patient can be reduced.

(Tenth Embodiment) This embodiment will be described with reference to FIGS. This embodiment is a mode in which the piezoelectric actuator according to the present invention is used to drive a diaphragm mechanism in a TV camera adapter mounted on an endoscope. FIG. 12 is a cross-sectional view of the TV camera adapter mounted on the eyepiece of the rigid endoscope, FIG. 13 is an explanatory view of the diaphragm mechanism portion, and FIG. 14 is an enlarged view of the actuator unit.

In FIG. 12, the TV camera adapter 5
0 is provided with a first mounting portion 54 that is attached to and detached from the eyepiece portion 53 of the endoscope 52 at one end of the lens barrel 51, and a TV camera 55 is detachably attached to the other end of the lens barrel 51. A second mounting portion 56 for mounting is provided. The lens barrel 51 of the adapter 50 is provided with a focus adjusting mechanism 57 and a diaphragm mechanism 58.
The focus adjusting mechanism 57 rotates the adjusting ring 59,
Focus adjustment is performed by changing the position of the lens group 60 on the optical axis L.

The diaphragm mechanism 58 adjusts the diaphragm amount by rotating a plurality of diaphragm blades 81 of the diaphragm mechanism portion as described later. The diaphragm mechanism 58 will be specifically described. As shown in FIG. 13, a ring-shaped rotary disc 66 that rotates around the optical axis L is provided, and an actuator unit 67 is provided on one surface side of the rotary disc 66.

A movable pin 69 is fixed to the rotary disc 66 of the diaphragm mechanism 58, and the movable pin 69 and the pin 72 of the fixed plate 71 are connected by a spring 73. And
In the plane of the fixed plate 71, the actuator unit 67 having the structure as described in the above-mentioned embodiment is provided. The circular tube 74 as the stationary member is fixed plate 71
A moving body 76 frictionally engaged with the piezoelectric element 77 fixedly attached thereto is housed in the circular tube 74. Further, the power feeding member is connected by the structure as described in the above-mentioned embodiment.

A shaft 78 is projectingly provided at the tip of the moving body 76, and a ridge 79 facing the movable pin 69 is provided at the tip of the shaft 78. The expansion / contraction axis direction of the piezoelectric element 77 is set in the tangential direction of a virtual circle centered on the optical axis L.

Three diaphragm blades 81 are provided at equal intervals,
A support pin 82 pivotally connects the middle portion thereof. A base end of the diaphragm blade 81 is connected to a drive pin 83 provided upright on the rotary disc 66. When the rotary disc 66 is rotated, the diaphragm blade 81 is rotated around the support pin 82 to adjust the diaphragm amount. Further, the rotating disc 66 includes
A guide hole 86 into which the guide pin 85 is fitted is provided.

Therefore, the piezoelectric actuator unit 67
As in the case of the above-described first embodiment, the piezoelectric element 77 of
When the drive waveform voltage is applied, the moving body 76 of the piezoelectric actuator moves forward and backward, thereby making
When the movable pin 69 pushes, the diaphragm blade 81 rotates to widen the optical path. On the other hand, when the moving body 76 of the piezoelectric actuator moves in the opposite direction, that is, when moving to the right in FIG. 14, the moving body 76 of the piezoelectric actuator moves to the right, so that the upright 79 moves to the right and the movable pin 66 moves. Spring 7
The restoring force of 3 causes the diaphragm blade 81 to rotate in the opposite direction by moving to the right, thereby covering the optical path. With the above operation, the light amount of the TV camera adapter can be reduced.

According to this structure, in addition to the effects of the first embodiment of the piezoelectric actuator described above, it is possible to realize a TV camera adapter that is resistant to external impact. Further, since the piezoelectric element is short, the actuator can be fixed on the diaphragm fixing plate so as not to protrude in the radial direction, so that the diameter of the TV camera adapter can be reduced.

(Eleventh Embodiment) This embodiment will be described with reference to FIGS. In this embodiment, the above-described piezoelectric actuator according to the present invention is used for driving an iris diaphragm mechanism in an endoscope. FIG. 15 is a sectional view of a distal end portion of an insertion portion of an endoscope as an electronic observation apparatus, and FIG.
FIG. 17 is an enlarged view of the piezoelectric actuator unit portion.

In FIG. 15, reference numeral 90 denotes a tip end main body in the insertion portion of the endoscope, and an imaging unit 92 connected to the observation window lens portion 91 is incorporated in the tip end main body 90. The imaging unit 92 includes an iris unit 94 for adjusting an aperture, an imaging lens 95 and a C
A solid-state image sensor 96 such as a CD is incorporated in a liquid-tight or air-tight manner.

The iris unit 94 is provided in the image forming lens group. FIG. 16 shows the iris unit 94. The iris unit 94, like the tenth embodiment described above, has a ring-shaped rotary disc 66 that rotates about its optical axis L, an aperture blade 81, a support pin 82, a drive pin 83, and a support pin 82. And the rotating disk 6
6 and a piezoelectric actuator unit 67 that rotates.

As shown in FIG. 16, there are three diaphragm blades 81, which are arranged at equal intervals, and each diaphragm blade 81 is pressed by a pressing member 97. The support pin 82 is erected on the diaphragm pressing member 97. An intermediate portion of the diaphragm blade 81 is pivotally attached by a support pin 82 thereof. The base end of the diaphragm blade 231 is the rotating disc 2
35 is connected to a drive pin 238 provided upright.

A pressing member 98 is fixed to the rotating disc 66. An actuator unit 67 is fixed to a base 99 of the iris unit 94. The actuator unit 67 is arranged in the space between the rotary disk 66 and the base 99 of the iris unit 94. As a result, it is compactly incorporated.

The structure of the actuator unit 67 is constructed as shown in FIG. That is, similar to the structure of the first embodiment described above, the circular tube 101 as a stationary member, the moving body 102, and the piezoelectric element 103 are provided, and the power feeding member 104 is connected to the piezoelectric element 103. The circular tube 101 as a stationary member is fixed to the base 99. A shaft 105 is provided on the moving body 102, and a flexible tube 106 is fixed to the tip of the shaft 105. The flexible tube 106 is fixed to the pressing member 98.

Therefore, when a driving voltage is applied to the piezoelectric element 103 through the feeding member 104 as in the case of the first embodiment, the moving body 102 of the piezoelectric actuator moves and pushes and pulls the pressing member 98. At this time, the displacement between the shaft 105 and the pressing member 98 is
It is absorbed by the flexible tube 106. When the pressing member 98 rotates, the rotary disc 66 also rotates accordingly, so that the diaphragm blade 81 rotates about the support pin 82,
Adjust the aperture.

According to this structure, in addition to the structure of the first embodiment, a piezoelectric actuator which is incorporated in the distal end portion of the endoscope and does not increase the diameter of the distal end portion and does not lengthen the rigid portion is provided. it can. Further, it is possible to provide a piezoelectric actuator capable of forming a small iris unit. Further, it is possible to provide a piezoelectric actuator capable of continuously adjusting the light amount. Further, since the actuator can be fixed on the diaphragm fixing plate, the diameter of the endoscope can be reduced.

(Twelfth Embodiment) This embodiment will be described with reference to FIG. In this embodiment, the treatment section of the endoscopic treatment instrument 110 is operated by using the rapid-deformation type piezoelectric actuator having the above-described configuration.

That is, in the treatment instrument 110, a rigid tube 112 having the same diameter or slightly smaller than that is coaxially connected to the tip of the flexible tube 111. Then, a rapid deformation type piezoelectric actuator 113 is incorporated in the rigid tube 112. The piezoelectric actuator 113 has the same structure as that of the above-described first embodiment, for example, and operates the arm of the treatment cup 114 which opens and closes by the link mechanism 115.

The piezoelectric actuator 113 is a moving body 116 fitted and inserted in the rigid tube 112 as a stationary member.
It has a piezoelectric element 117 attached to the moving body 116. Then, the piezoelectric element 1 of the piezoelectric actuator 113
A lead wire 118 as a power feeding member is connected to 17 with a structure similar to that of the first embodiment described above. The lead wire 118 is connected to an external piezoelectric actuator control device 119 through the inside of the flexible tube 111.

When the driving voltage as described above is applied to the piezoelectric element 117 through the lead wire 118 and the piezoelectric element 117 expands and contracts, the link mechanism 11
The cup 114 is opened / closed via 5.

Since the piezoelectric actuator 113 is configured as described above, it is possible to obtain a treatment tool that is strong against external impacts, in addition to the effect as a piezoelectric actuator similar to that of the first embodiment described above. In particular, it can be bent with a small curvature by incorporating it into a medical treatment tool having a curved tip, without increasing the diameter of the tip portion and without lengthening the rigid portion of the insertion portion.

Further, since it is not necessary to push and pull the link mechanism with a wire as in the conventional case, it is possible to provide a piezoelectric actuator and a treatment tool capable of smoothly opening and closing the treatment cup 114 even if the flexible tube 111 is bent with a small curvature. .

(Thirteenth Embodiment) This embodiment will be described with reference to FIGS. 19 and 20. In this system, an ultrasonic wave transmitting / receiving unit 161 provided in a probe 160 of a three-dimensional ultrasonic endoscope apparatus is moved by a piezoelectric actuator 162 of the present invention to perform scanning. The ultrasonic transmission / reception element 163 is supported by the rotation of a motor 165 whose rotation is controlled by a motor drive circuit 164, and the rotation is detected by an encoder 166.
A unit including the ultrasonic transmitting / receiving element 163, the motor 165, and the encoder 166 is held and moved by the moving body 167 of the piezoelectric actuator 162.

The moving body 167 has a plurality of legs 169 which are pressed against the inner surface of a cylindrical stationary member 168.
It is built in so that it can slide along the inner surface of 8.
The moving body 167 can move along the rotation axis direction of the ultrasonic transmitting / receiving element 163.

A laminated piezoelectric element 170 similar to that described above is attached to the moving body 167 with its laminating direction aligned with the axial direction. The piezoelectric element 170 has one end attached to the base of the moving body 167, and the lead wire 171 is attached to the free end of the piezoelectric element 170 in the same connection structure as described above. The lead wire 171 is connected to the piezoelectric actuator control circuit 172.

On the side surface of the piezoelectric element 170, a magnetic thin film 173 that is polarized in a stripe shape in the axial direction is attached. on the other hand,
A cylindrical stationary member 168 corresponding to the magnetic thin film 173.
An MR sensor 174 is installed on the inner surface of the.

A pair of spring electrodes 175 are provided so as to project from the ultrasonic transmitting / receiving element 163, and the spring electrodes 175 come into contact with the electrodes formed on the inner surface of the stationary member 168. An ultrasonic observation device 177 is connected to this electrode. Further, the signal of the MR sensor 174 which detects the position of the moving body 167 of the piezoelectric actuator 162 by detecting the magnetic thin film 173 is input to the ultrasonic observation device 177 thereof, and this signal is transmitted to the piezoelectric actuator control circuit 17.
Enter 2 as well.

The ultrasonic observation device 177 includes an encoder 1
The signal of 66 is input and the ultrasonic transmitting / receiving element 1
The echo signal from 63 is input. Ultrasonic observation device 1
The output signal of 77 is input to the first CRT 181 and is used to display a secondary image of an ultrasonic image obtained by radial scanning, and at the same time, the three-dimensional image processing device 182 is used.
Entered in. The signal from the MR sensor 174 that detects the magnetic thin film 173 is transmitted to the piezoelectric actuator control circuit 17
2 and the transmission circuit 183.

Further, the reference clock signal generated by the timing circuit 184 is input to the distance meter 185 and the piezoelectric actuator control circuit 172. The piezoelectric actuator control circuit 172 controls the operation of the piezoelectric actuator 162 according to the timing. The piezoelectric actuator control circuit 172 outputs a drive signal according to the reference clock signal from the timing circuit 184 and the signal from the MR sensor 174. For example, the piezoelectric actuator 162 is driven by the drive signal having the waveform as described above, and the moving body 167 is appropriately moved. Since this operation is the same as that described above, detailed description will be omitted. By this operation, the rotating ultrasonic transmitting / receiving element 163 is moved and scanned in the axial direction.

The output signal of the distance meter 185 for measuring the moving distance of the piezoelectric actuator 162 is the three-dimensional image processing apparatus 1.
82 is input. The three-dimensional image processing device 182 performs image processing based on this signal and the signal from the ultrasonic observation device 177, and the output signal thereof is input to the second CRT 186 and used for displaying a three-dimensional image.

According to this structure, the piezoelectric actuator 1
In addition to the first embodiment of No. 62, in particular, it is possible to provide a piezoelectric actuator that is incorporated in the distal end portion of a three-dimensional ultrasonic endoscope and does not make the rigid portion longer without increasing the diameter of the distal end portion. . Furthermore, it is possible to obtain an ultrasonic probe that is resistant to external impact. Further, by shortening the piezoelectric element, it is possible to shorten the rigid length of the probe,
The insertability is improved and the burden on the patient can be reduced.

FIG. 21 shows a modification of the piezoelectric actuator 162 in the probe 160. The length of the tip of the piezoelectric element 170 protrudes from the tip of the moving body 167.

(Fourteenth Embodiment) This embodiment is a modification of the piezoelectric actuator. As shown in FIG. 22,
The piezoelectric actuator 120 includes a piezoelectric element 121,
The resin-based moving body 12 provided on the other end of the piezoelectric element 121.
2, a stationary member 123 composed of a tubular member with which the moving body 122 is frictionally engaged, and a pair of upper and lower power feeding members which are slidably in contact with and electrically connected to electrodes 124 formed on the upper and lower surfaces of the piezoelectric element 121. And 125. The moving body 122 has a pair of left and right leg (beam) portions 126 extending in the same direction from the base portion, and the stationary member 1 is provided at the tip thereof.
A protrusion 127 that elastically hits and frictionally engages the inner surface of 23 is provided. That is, the moving body 122 has the legs 126.
The protrusion 127 is slidably frictionally engaged with the stationary member 123 by the spring force of the.

Feeding members 125 corresponding to the electrodes 124 are provided on the upper and lower surfaces of the piezoelectric element 121, which do not face the surfaces of the legs 126 of the moving body 123, respectively. One end portion of the power feeding member 125 has the stationary member 12
3, and at least one contact point 128 which is in contact with the electrode 124 on the side of the piezoelectric element 121 is provided at an end portion or in the middle of the power feeding member 125. The power feeding member 125 is fixed to the stationary member 123. The electrode 124 on the side of the piezoelectric element 121 also constitutes a power feeding member together with the power feeding member 125.

The piezoelectric element 12 is fed through the power feeding member 125.
A drive voltage is applied to 1. Contact point 1 of the power feeding member 125
A voltage is applied to the electrode 124 of the piezoelectric element 121 via 28. When the voltage waveform shown in FIG. 2 is used, the moving body 122 of the piezoelectric actuator 120 can be moved to the left side or the right side according to the same principle as in the first embodiment. At that time, a movement amount corresponding to the length of the piezoelectric element 121 can be secured.

According to the arrangement of the members of the power feeding system,
Since there is no interference between the leg 126 of the piezoelectric element 121 and the power feeding member 125, the power feeding member 125 or the like is not broken and durability is improved. Further, in this embodiment, since the power feeding member 125 does not move with respect to the stationary member 123, the space for housing the power feeding member 125 can be omitted, and the piezoelectric actuator 120 can be shortened. Further, in this embodiment, the length of the piezoelectric element 121 is made longer than the length of the leg 126 of the moving body 122,
Since the range of the electrode 124 is long, a sufficient amount of movement can be obtained. Further, generally, as the length of the piezoelectric element 121 increases, the generated force increases, so that a large force can be generated. However, the tip of the piezoelectric element 121 and the leg 126 of the moving body 123.
The tips may be substantially aligned or the piezoelectric element 121 may be shorter.

(Fifteenth Embodiment) This embodiment is shown in FIG. In this embodiment, a piezoelectric actuator is incorporated in the distal end portion of the endoscope, and a movable lens in the lens group of the observation optical system or the image pickup optical system is moved so that zooming and focusing can be performed. The specific configuration of the tip of the electronic endoscope is the same as that shown in FIG. 10 in the above-described ninth embodiment.

The actuator unit incorporated in the distal end portion of the endoscope is constructed as shown in FIG. 23, and the members designated by the same reference numerals as those in the ninth embodiment are the members of the ninth embodiment. Common with things.

In the fifteenth embodiment, the lead wire 8 as the power feeding member passes through the groove portion 141 provided in the base portion of the moving body 2 and extends toward the shaft 45. The lead wire 8 is adhesively fixed in the groove portion 141. The lead wire 8 as the power feeding member extending from the moving body 2 is folded back toward the beam 6 of the moving body 2 with a slack enough to absorb the moving amount of the moving body 2, and passes through the passage 142. Guided backwards.

As in the above-described embodiment, however, by applying a drive waveform voltage to the piezoelectric element 3 of the piezoelectric actuator through the lead wire 8, the moving body 2 moves in the optical axis direction. The driving force generated at that time is the shaft 4
5 is transmitted to the movable frame 42, and the movable frame 42 moves in the optical axis direction. By moving the movable frame, engineering zooming or focusing is performed.

Since this piezoelectric actuator is an actuator constructed in the same manner as in the first embodiment, the tip of the endoscope will not become long due to the incorporation of the actuator. Further, since the space for accommodating the bending of the lead wire 8 as the power feeding member when the piezoelectric actuator is operated is provided around the shaft 45, the accommodating portion does not project to the rear of the piezoelectric actuator portion, The tip of the endoscope does not become long.

According to this structure, since the lead wire 8 as the power feeding member is adhered and fixed to the moving body 2, the durability is improved as compared with the case where the power feeding member is attached only to the piezoelectric element. Further, by incorporating it into the distal end portion of the endoscope, it is possible to provide an actuator capable of zooming or focusing without increasing the diameter of the distal end portion and lengthening the rigid portion. Moreover, since the rigid portion is short, the endoscope can be bent with a small curvature. Also, since this actuator is used, accurate zooming or focusing can be performed.

According to the above-mentioned aspect, various configurations shown in the following sections can be obtained. 1. A stationary member, a moving body that is slidably frictionally engaged with the stationary member, is deformed in the axial direction by applying a drive voltage, and one end portion in the axial direction is connected to the moving body. A piezoelectric actuator having a piezoelectric element, wherein the piezoelectric element is arranged at a position included in the outer shape of the moving body in at least one direction in a direction perpendicular to the axial direction of the piezoelectric element. .

2. 2. The piezoelectric actuator according to claim 1, wherein one end of the piezoelectric element connected to the moving body is inside the moving body. 3. The position of the other end of the piezoelectric element is approximately the same as that of the moving body (including the same position),
2. The piezoelectric actuator according to item 2. 4. The piezoelectric actuator according to any one of items 1, 2, and 3, wherein the width of the piezoelectric element is shorter than that of the moving body. 5. 5. The piezoelectric actuator according to any one of claims 1 to 4, wherein the piezoelectric element is attached to the moving body so as to be easily deformed in a certain direction of the moving body. 6. When the piezoelectric actuator receives an impact from the outside, the piezoelectric element has such a length as to hit the moving body first,
First to fifth characterized in that the piezoelectric element is configured
Piezoelectric actuator according to the item.

7. 7. The piezoelectric actuator according to any one of items 1 to 6, wherein the piezoelectric element is a laminated piezoelectric element.

8. 8. The piezoelectric actuator according to any one of items 1 to 7, wherein the cross-sectional shape of the laminated element is a quadrangle or a rectangle.

9. 8. The piezoelectric actuator according to any one of 1 to 7, wherein the laminated element has a circular cross-sectional shape.

10. 10. The piezoelectric actuator according to any one of items 1 to 9, wherein the moving body is made of metal and formed into a beam shape.

11. 11. The piezoelectric actuator according to claim 1, wherein the metal forming the moving body is a light metal.

12. 10. The piezoelectric actuator according to any one of items 1 to 9, wherein the moving body is formed in a non-metal beam shape. Since the moving body made of metal is processed by cutting, the workability is poor. Moreover, although electrical insulation processing must be performed, the configuration of this twelfth item can provide a piezoelectric actuator that is easy to manufacture and manufacture.

13. 13. The piezoelectric actuator according to any one of items 1 to 12, wherein the stationary member is a metal circular tube.

14. The first to thirteenth features that the metal forming the stationary member is a light metal
Piezoelectric actuator according to the item.

15. 14. The piezoelectric actuator according to any one of claims 1 to 13, wherein the stationary member is a non-metallic circular tube.

16. 16. The piezoelectric actuator according to Item 15, wherein the non-metal of the material forming the stationary member is resin.

17. 17. The piezoelectric actuator according to any one of items 1 to 16, characterized in that heat dissipation means is provided between the moving body and the piezoelectric element.

18. Item 18. The piezoelectric actuator according to Item 17, wherein a heat conducting medium is filled between the moving body and the piezoelectric element as the heat radiating means.

19. 19. The piezoelectric actuator according to item 18, wherein heat conducting grease is used as the heat conducting medium.

20. 20. The piezoelectric actuator according to any one of items 1 to 19, wherein a beam facing the moving body is provided, and a shock absorbing member is provided between the beams.

21. Item 21. The piezoelectric actuator according to Item 20, wherein an elastic member is provided as the shock absorbing member.

22. Item 22. The piezoelectric actuator according to Item 21, wherein rubber is provided as the elastic member.

23. A tenth, a second, and a tenth aspect in which a plurality of beams of the moving body are provided laterally of the piezoelectric element.
The piezoelectric actuator according to paragraphs 1 and 22.

24. Item 24. The piezoelectric actuator described in Item 23, wherein the number of the beams is three.

25. The moving body is formed in a tubular shape, a slit is provided in a part of the moving body to form a beam, and the moving body is fitted into the hole of the stationary member. The piezoelectric actuator described.

26. Built into the tip of the insertion part of the endoscope,
26. The piezoelectric actuator according to any one of items 1 to 25, which operates an internal mechanism.

27. A twenty-sixth aspect characterized by being applied to a drive source of a zoom mechanism or a focus mechanism of an endoscope.
Piezoelectric actuator according to the item.

28. 27. The piezoelectric actuator according to Item 26, which is applied to a drive source of a light amount diaphragm mechanism of an endoscope.

29. The piezoelectric actuator according to any one of claims 1 to 25, which is provided on a surface of an adapter for a TV camera of an endoscope.

30. The piezoelectric actuator according to any one of claims 1 to 25, which is applied to an operation drive source of a medical treatment tool.

31. 26. The piezoelectric actuator according to any one of items 1 to 25, which is applied to a driving source of a three-dimensional ultrasonic probe.

32. A stationary member, a moving body that is slidably frictionally engaged with the stationary member, is deformed in the axial direction by applying a drive voltage, and one end portion in the axial direction is connected to the moving body. In a piezoelectric actuator having a piezoelectric element, the piezoelectric element is arranged at a position where the piezoelectric element is included in the outer shape of the moving body in a moving direction of the moving body and at least one direction perpendicular to the moving direction. Piezoelectric actuator characterized by.

33. A first to a first aspect of the present invention, further comprising a power feeding member that feeds power to the piezoelectric element, and a connecting portion between the piezoelectric element and the power feeding member is provided in a portion that does not face a member of the moving body and avoids it. 33. The piezoelectric actuator according to item 32.

34. The moving body has a plurality of legs slidably frictionally engaged with a stationary member, and the connecting portion is provided at a portion not facing the legs and avoiding the legs. Item 33. The piezoelectric actuator according to Item 33.

35. 35. The piezoelectric actuator according to any one of items 1 to 34, wherein a laminated piezoelectric ceramic element is used as the piezoelectric element.

36. The piezoelectric actuator according to any one of items 1 to 35, wherein an adhesive is used to connect the piezoelectric element and the moving body.

37. The piezoelectric actuator according to item 1, wherein a metal is used as a material of the moving body, and the metal is preferably aluminum.

38. 2. The piezoelectric actuator according to item 1, wherein solder is used to connect the power feeding member and the piezoelectric element.

39. 2. The piezoelectric actuator according to item 1, wherein a conductive adhesive is used to connect the power feeding member and the piezoelectric element.

40. 2. The piezoelectric actuator according to item 1, wherein the piezoelectric element is coated with a polyparaxylylene coat. It has a sealing and moisture-proof effect.

41. 2. The piezoelectric actuator according to claim 1, wherein the moving body and the stationary member that is in sliding contact with the moving body have the same cross-sectional shape in the sliding contact surface. If the posture of the moving body with respect to the stationary member is not good, it may get caught or bite,
Sufficient performance cannot be obtained and durability is reduced. It is necessary to keep the posture constant. According to this, a highly durable actuator can be provided.

42. 2. The piezoelectric actuator according to claim 1, wherein the length of the leg of the moving body is longer than the length of the piezoelectric element.

43. 2. The piezoelectric element according to claim 1, wherein the length of the leg of the moving body is longer than the length of the piezoelectric element, but the length is included in the outer shape of the moving body in terms of impact resistance. Actuator.

44. 2. The piezoelectric actuator according to item 1, wherein the power feeding member is provided so as to be movable with respect to the piezoelectric element while electrically contacting the electrode of the piezoelectric element. This is suitable for long piezoelectric elements.

45. The piezoelectric actuator according to Item 44, wherein the power feeding member is fixed within a circle circumscribing the moving body.

46. 44. The piezoelectric actuator according to any one of items 1 to 43, wherein the power feeding member is led out in a direction opposite to a direction in which the moving body and the piezoelectric element are connected.

47. 47. The piezoelectric actuator according to Item 46, wherein the power feeding member is fixed to the moving body.

48. 48. The piezoelectric actuator according to any one of claims 1 to 47, wherein an inertial body that is a member different from the piezoelectric element is attached to the other end of the piezoelectric element whose one end side is connected to the movable body.

[0124]

As described above, according to the present invention, it is possible to reduce the size of the piezoelectric actuator and improve the durability against impact, and it is applied to medical equipment and optical equipment which are highly invasive and have high performance. It is possible to provide a piezoelectric actuator that can realize the above.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a piezoelectric actuator according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of a waveform of a drive voltage applied to a piezoelectric actuator.

FIG. 3 is an explanatory diagram of a piezoelectric actuator according to a second embodiment of the present invention.

FIG. 4 is an explanatory diagram of a piezoelectric actuator according to a third embodiment of the present invention.

FIG. 5 is an explanatory diagram of a piezoelectric actuator according to a fourth embodiment of the present invention.

FIG. 6 is an explanatory diagram of a piezoelectric actuator according to a fifth embodiment of the present invention.

FIG. 7 is an explanatory diagram of a piezoelectric actuator according to a sixth embodiment of the present invention.

FIG. 8 is a vertical sectional view of a piezoelectric actuator according to a seventh embodiment of the present invention.

FIG. 9 is a cross sectional view of a piezoelectric actuator according to an eighth embodiment of the present invention.

FIG. 10 is an explanatory diagram of an example in which a piezoelectric actuator according to a ninth embodiment of the present invention is used to drive an optical system of an endoscope.

FIG. 11 is an explanatory diagram around a piezoelectric actuator in the ninth embodiment of the present invention.

FIG. 12 is an explanatory diagram of an example in which a piezoelectric actuator is used for driving a diaphragm mechanism in a TV camera adapter according to a tenth embodiment of the present invention.

FIG. 13 is an explanatory diagram of a portion of a diaphragm mechanism according to a tenth embodiment of the present invention.

FIG. 14 is an explanatory diagram of a portion of a piezoelectric actuator that drives a diaphragm mechanism according to a tenth embodiment of the present invention.

FIG. 15 is an explanatory diagram of an example in which a piezoelectric actuator is used to drive an iris diaphragm mechanism in an endoscope according to an eleventh embodiment of the present invention.

FIG. 16 is an explanatory diagram of a portion of an iris diaphragm mechanism according to an eleventh embodiment of the present invention.

FIG. 17 is an explanatory diagram of a portion of a piezoelectric actuator that drives an iris diaphragm mechanism according to an eleventh embodiment of the present invention.

FIG. 18 is an explanatory view of an example of a treatment tool for an endoscope using a piezoelectric actuator according to the twelfth embodiment of the present invention.

FIG. 19 is an explanatory diagram of an example in which a piezoelectric actuator is applied to an ultrasonic transmission / reception unit of a three-dimensional ultrasonic endoscope apparatus according to a thirteenth embodiment of the present invention.

FIG. 20 is an explanatory diagram of a portion of the piezoelectric actuator of the thirteenth embodiment of the present invention.

FIG. 21 is an explanatory diagram of a modification of the thirteenth embodiment of the present invention.

FIG. 22 is an explanatory diagram of a piezoelectric actuator according to a fourteenth embodiment of the present invention.

FIG. 23 is an explanatory diagram showing a modification of the ninth embodiment of the present invention.

[Explanation of symbols]

1 ... Stationary member, 2 ... Moving body, 3 ... Piezoelectric element, 4 ... Circular tube,
6 ... Beam, 8 ... Lead wire.

[Procedure amendment]

[Submission date] June 20, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

The space between the piezoelectric element 3 and the opposing flat surfaces of the pair of beams 6 of the moving body 2 is filled with a heat conductive grease 11 for heat dissipation. This grease 1
A leaf spring 12 is attached and fixed to the front end surface and the left and right end surfaces of the moving body 2 so as to prevent 1 from spilling around. The lead wire 8 is the leaf spring 12
It is led out through a small hole 13 provided in the. Gap of the lead-out portion, for example Poriparakishiri Les emissions (trade name ...
Parylene) is covered and sealed by the seal 14. It also serves as a sterilization resistant structure.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0049

[Correction method] Change

[Correction content]

As shown in FIG. 16, there are three diaphragm blades 81, which are arranged at equal intervals, and each diaphragm blade 81 is pressed by a pressing member 97. The support pin 82 is erected on the diaphragm pressing member 97. An intermediate portion of the diaphragm blade 81 is pivotally attached by a support pin 82 thereof. The base end of the diaphragm blade 81 has a rotating disc 66.
Is connected to a drive pin 83 provided upright.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0077

[Correction method] Change

[Correction content]

As in the above-described embodiment, however, by applying a drive waveform voltage to the piezoelectric element 3 of the piezoelectric actuator through the lead wire 8, the moving body 2 moves in the optical axis direction. The driving force generated at that time is the shaft 4
5 is transmitted to the movable frame 42, and the movable frame 42 moves in the optical axis direction. By this movement of the movable frame, zooming or focusing of the optical system is performed.

Claims (1)

[Claims] 1. A stationary member, a moving body that is slidably frictionally engaged with the stationary member, and expands and contracts in the axial direction by applying a drive voltage, and one end portion in the axial direction is formed. A piezoelectric actuator having a piezoelectric element connected to the moving body, wherein the piezoelectric element is arranged at a position included in the outer shape of the moving body in at least one direction in a direction perpendicular to the axial direction of the piezoelectric element. Piezoelectric actuator characterized by.