JP6056224B2 - Vibration wave motor - Google Patents

Description

  The present invention relates to a vibration wave motor.

  A vibrator of a vibration wave motor used in an imaging apparatus or the like is generally composed of a metal elastic body and a piezoelectric body, and the piezoelectric body is generally a single layer. In order to drive an ultrasonic motor using such a piezoelectric element with a practical output, a high frequency voltage of several tens of volts is required, so the voltage of the battery of the photographing device is insufficient, There is something to prepare. However, since the booster circuit raises the problem of cost increase and device enlargement, there is also a vibration wave motor that secures a high voltage by stacking piezoelectric bodies (see Patent Document 1).

JP-A-7-213081

  However, the laminated piezoelectric material described in the above document is complicated because the electrode pattern of each layer is different. Another problem is that the layer bonded to the elastic body and the anti-bonding layer are not polarized, and these unpolarized layers inhibit excitation of vibration waves.

  An object of the present invention is to provide a vibration wave motor that can be driven with a simple configuration and a low voltage.

The present invention solves the above problems by the following means .

  The vibration wave motor of the present invention has a second electrode pattern in which a first electrode pattern is formed on one surface and a driving signal having a first phase is input on the other surface, and a phase different from the first phase. An electromechanical transducer laminated body in which a first electromechanical transducer having a third electrode pattern to which a drive signal is input and a fourth electrode pattern are laminated so that surfaces having the same electrode pattern face each other; , An elastic body in contact with the electromechanical transducer stack, and a relative movement member driven by the elastic body, wherein the electromechanical transducer stack includes the first electromechanical transducer and the first electromechanical transducer The second electromechanical transducer element that is inverted about the target axis with a part of the fourth electrode pattern of one electromechanical transducer element as the target line is stacked.

  According to the present invention, it is possible to provide a vibration wave motor that can be driven with a simple configuration and a low voltage.

It is a figure explaining the vibration wave motor of 1st embodiment of this invention. It is a block diagram explaining the drive device of the vibration wave motor of a first embodiment. It is a figure which shows the lens barrel which mounts the vibration wave motor of 1st embodiment. It is a figure explaining the elastic body containing a piezoelectric material. It is a figure explaining the piezoelectric material of a first embodiment, (a) is a side view of a piezoelectric material, (b) is a figure showing the surface of a piezoelectric material, (c) A sectional view of a piezoelectric material, (d) is a figure. It is the figure which showed the back surface of the piezoelectric material. It is a figure explaining the elastic body containing a piezoelectric material, (a) is a side view, (b) is the figure seen from the FPC side. It is a figure explaining the electrode pattern of each single layer piezoelectric material, (a) is the figure which showed the electrode pattern of the front and back of each single layer piezoelectric material, (b) is each single layer piezoelectric material in a laminated piezoelectric material It is the figure which showed the polarization direction. It is the figure which showed the expansion-contraction of the piezoelectric material by an applied voltage, (a) is a figure which showed the case where an applied voltage is positive, (b) is the case where an applied voltage is negative. It is a figure explaining the lens-barrel of 2nd embodiment of this invention.

(First embodiment)
Hereinafter, embodiments of a vibration wave motor 1 according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a diagram illustrating a vibration wave motor 1 according to a first embodiment of the present invention.
In this embodiment, the vibrator 10 side is fixed, and the movable element (relative motion member) 20 is driven.
The mover 20 is made of a light metal such as aluminum, and the surface of the sliding surface is subjected to surface treatment for improving wear resistance.

  As will be described later, the vibrator 10 includes an electromechanical transducer (hereinafter referred to as a piezoelectric body) 11, such as a piezoelectric element or an electrostrictive element that converts electrical energy into mechanical energy, and the piezoelectric body 11. And an elastic body 12 bonded to each other, and a progressive vibration wave is generated in the vibrator 10.

The elastic body 12 is made of a metal material having a high resonance sharpness, and has a ring shape.
The piezoelectric body 11 is bonded to one surface (bonding surface 12f) of the elastic body 12, and a groove 12b is cut on the opposite side to the one surface. Then, the tip of the protruding portion (location without the groove 12 b) 12 c becomes the driving surface 12 a and is brought into pressure contact with the moving element 20.
The portion of the elastic body 12 where the groove 12b is not cut is a base portion 12d, and a flange 12e extends from the base portion 12d to the inner diameter side. The innermost diameter portion of the flange 12 e is fixed to the fixing member 13.
The protruding portion 12c of the elastic body 12 is provided with a sliding member such as a coating film or lubricating plating so as to cover the whole.

As will be described in detail later, the piezoelectric body 11 has electrodes disposed on the opposite side (FPC side, surface side) to the adhesive surface with the elastic body 12, and includes two phases (A phase, It has a two-group structure divided into (B phase).
In each phase, electrodes are arranged so that they are alternately polarized every ½ wavelength, and an interval of ¼ wavelength is provided between the A phase and the B phase.

The output shaft 21 is coupled to the mover 20 via a stopper member 23 inserted so as to fit the rubber member 22 and the D-cut of the output shaft 21. The output shaft 21 and the stopper member 23 are fixed by an E clip 24 or the like, and are rotated integrally with the mover 20.
The rubber member 22 between the stopper member 23 and the mover 20 has a function of coupling with the mover 20 and the stopper member 23 due to adhesiveness of rubber, and does not transmit vibration from the mover 20 to the output shaft 21. Butyl rubber having a function of absorbing vibration is preferable.
The pressure member 25 is provided between the output gear 51 of the output shaft 21 and the bearing 27. With such a structure, the moving element 20 is in pressure contact with the drive surface 12 a of the elastic body 12.

FIG. 2 is a block diagram illustrating the driving device 30 of the vibration wave motor 1 according to the first embodiment.
First, the drive / control unit 31 of the vibration wave motor 1 will be described.
The oscillating unit 32 generates a drive signal having a desired frequency according to a command from the control unit 31.
The phase shifter 33 divides the drive signal generated by the oscillator 32 into two drive signals having different phases.

The amplifying unit 34 boosts the two drive signals divided by the phase shift unit 33 to respective desired voltages.
A drive signal from the amplifying unit 34 is transmitted to the vibration wave motor 1, and a traveling wave is generated in the vibrator 10 by the application of the drive signal, so that the movable element 20 is driven.
The rotation detection unit 35 is configured by an optical encoder, a magnetic encoder, or the like, detects the position or speed of a driven object driven by driving the moving element 20, and transmits the detected value to the control unit 31 as an electric signal.

  The control unit 31 controls driving of the vibration wave motor 1 based on a drive command from the CPU 36 in the lens barrel 110 or the camera body. The control unit 31 receives the detection signal from the rotation detection unit 35, obtains position information and speed information based on the values, and controls the frequency of the oscillation unit 32 so as to be positioned at the target position.

Next, the operation of the vibration wave motor 1 of the first embodiment will be described.
When a drive command is issued from the control unit 31, the oscillation unit 32 generates a drive signal.
The drive signal is divided into two drive signals having a phase difference of 90 degrees by the phase shifter 33, and is amplified to a desired voltage by the amplifier 34.
The amplified drive signal is applied to the piezoelectric body 11 of the vibration wave motor 1, and the piezoelectric body 11 is excited (vibrated). Due to the excitation of the piezoelectric body 11, fourth-order bending vibration is generated in the elastic body 12. The piezoelectric body 11 is divided into an A phase and a B phase, and drive signals are applied to the A phase and the B phase, respectively.

  The positional phase of the quaternary bending vibration generated from the A phase and the quaternary bending vibration generated from the B phase are shifted by ¼ wavelength. In addition, since the phase A drive signal and the phase B drive signal are 90 degrees out of phase, the two bending vibrations are combined into four traveling waves.

Elliptic motion occurs at the front of the traveling wave. Therefore, the movable element 20 that is in pressure contact with the drive surface 12a is frictionally driven by this elliptical motion.
An optical encoder is arranged in the driving body driven by driving the moving element 20, and an electric pulse is generated therefrom and transmitted to the control unit 31. Based on this signal, the control unit 31 can obtain the current position and the current speed.

FIG. 3 is a diagram showing a lens barrel 110 on which the vibration wave motor 1 of the first embodiment is mounted.
The vibration wave motor 1 is attached to the gear unit module 113, and the gear unit module 113 is attached to the fixed barrel 114 of the lens barrel 110.
Rotational motion of the output gear 51 of the vibration wave motor 1 is transmitted to the cam ring 116 via the reduction gear 115 of the gear unit module 113, and the cam ring 116 is driven to rotate.
A key groove 117 is cut obliquely with respect to the circumferential direction in the cam ring 116, and the AF ring 119 in which the fixing pin 118 is inserted into the key groove 117 is rotated by the cam ring 116, It is driven in the straight direction in the direction of the axis OA and can stop at a desired position.
The circuit 121 is provided between the outer fixed cylinder 114a and the inner fixed cylinder 114b of the lens barrel 110, and performs driving and control of the vibration wave motor 1, detection of the rotational speed, detection of the vibration sensor, and the like.

Next, the piezoelectric body 11 will be described in detail.
FIG. 4 is a diagram illustrating the piezoelectric body 11 according to the first embodiment. FIG. 4A is a part of a side view of the piezoelectric body 11 (viewed from a direction orthogonal to the pressing direction of the vibration wave motor 1). FIG. 4B is a view showing the surface 11A of the piezoelectric body 11, and FIG. 4A is a view seen from the aa direction of FIG. FIG.4 (c) is cc sectional drawing of (b). FIG. 4D is a view showing the back surface 11 </ b> B of the piezoelectric body 11.
FIG. 5 is a diagram illustrating the vibrator 10 including the piezoelectric body 11 and the elastic body 12. 5A is a side view, and FIG. 5B is a view seen from the FPC 14 side.

The substrate of the piezoelectric body 11 is composed of lead zirconate titanate called PZT, or barium titanate, bismuth sodium titanate, bismuth potassium titanate, etc. which are lead-free materials in recent years due to environmental problems.
Electrodes are arranged on the surface 11A of the substrate of the piezoelectric body 11, and a silver paste is printed thereon. The electrode may be a metal plating such as NiP or gold.

In addition, as shown in FIGS. 4A and 4C, the piezoelectric body 11 includes a single-layer piezoelectric body 111 (a first-layer piezoelectric body 111a, a second-layer piezoelectric body 111b, and a third-layer piezoelectric body 111c). (Three layers in this embodiment) are stacked. Hereinafter, in order to distinguish the piezoelectric body 11 from the single-layer piezoelectric body 111, the multilayer piezoelectric body 11 is appropriately referred to.
The first-layer piezoelectric body 111a, the second-layer piezoelectric body 111b, and the third-layer piezoelectric body 111c are arranged in this order on the side opposite to the bonding surface of the laminated piezoelectric body 11 with the elastic body 12 (FPC side, hereinafter referred to as the surface 11A). ) Are lined up.

An applied electrode pattern 16 is formed on the surface 11A side of the laminated piezoelectric body 11, and is divided into two phases (A phase and B phase) along the circumferential direction.
In each phase, electrodes are arranged so that they are alternately polarized every ½ wavelength, and an interval of ¼ wavelength is provided between the A phase and the B phase.

As shown in FIGS. 5A and 5B, a flexible printed circuit board (FPC) 14 is joined to the surface 11A in order to transmit a drive signal.
As shown in FIG. 5A, an adhesive 18 is applied so as to extend from the side surfaces of the elastic body 12 and the piezoelectric body 11 to the FPC 14 to reinforce the adhesive strength.

As shown in FIG. 4D, the back surface 11B of the laminated piezoelectric body 11 is not a divided electrode pattern 16 but a common electrode pattern 19 that is a common electrode of two drive signal phases (A phase and B phase). Is formed. In this embodiment, the back surface 11B is joined to the elastic body 12 with a room temperature curable adhesive.
As shown in FIG. 4A, each of the electrode patterns 16 and 19 is partially extended to the outer peripheral side to form a conductive portion 18a, and is electrically connected to the electrode patterns 16 and 19 of the respective layers along the outer peripheral side surface. . In the present embodiment, the conduction of the electrode patterns 16 and 19 of each layer is performed on the outer peripheral side, but may be performed on the inner peripheral side.

  FIG. 6 is a diagram for explaining the electrode patterns of each single-layer piezoelectric body 111. FIG. 6A is a diagram showing the electrode patterns on the front and back surfaces of each single-layer piezoelectric body 111, and FIG. is there.

As shown in FIG. 6 (a), the applied electrode pattern 16 is disposed on the surface 111aA side of the first layer piezoelectric body 111a, which is composed of two drive signal phases (A phase, B) along the circumferential direction. Phase). In each phase, the electrodes 16 are alternately polarized every ½ wavelength, and the electrodes 16 are arranged such that an interval of ¼ wavelength is provided between the A phase and the B phase.
On the back surface 111aB of the first-layer piezoelectric body 111a, not the divided application electrode pattern 16 but a common electrode pattern 19 of two drive signal phases (A phase and B phase) is formed.

On the surface 111bA of the second layer piezoelectric body 111b, not the divided application electrode pattern 16 but a common electrode of two drive signal phases (A phase and B phase) is formed. Then, the front surface 111bA of the second layer and the back surface 111aB of the first layer are bonded together.
The applied electrode pattern 16 is arranged on the back surface 111bB side of the second layer piezoelectric body 111b, and is divided into two drive signal phases (A phase and B phase) along the circumferential direction. In each phase, the electrodes 16 are arranged so that they are alternately polarized every ½ wavelength, and an interval of ¼ wavelength is left between the A phase and the B phase.

On the surface 111cA of the third-layer piezoelectric body 111c, the electrode 16 is disposed, which is divided into two drive signal phases (A phase and B phase) along the circumferential direction. In each phase, the electrodes 16 are alternately arranged every ½ wavelength as shown in the figure, and an electrode 16 is arranged between the A phase and the B phase so that an interval of ¼ wavelength is left. The back surface 111bB of the second layer piezoelectric body 111b and the front surface 111cA of the third layer piezoelectric body 111c are bonded together.
On the back surface 111cB of the third-layer piezoelectric body 111c, not a divided electrode pattern, but a common electrode pattern 19 of two drive signal phases (A phase and B phase) is formed.

  As shown in FIG. 6B, the polarization of each layer (the first layer piezoelectric body 111a, the second layer piezoelectric body 111b, and the third layer piezoelectric body 111c) is a quarter wavelength between the A phase and the B phase. Excluding the minutely spaced portion 17, the polarization direction from the odd-numbered-layer-numbered joint surface side to the anti-joint surface side is opposite to the polarization direction from the even-numbered-number-numbered joint surface side to the anti-joint surface side.

That is, in the first layer piezoelectric body 111a in the region P shown in FIG. 6B, when the polarization direction is from the back surface 111aB side to the front surface 111aA side (this direction is defined as the + direction), the second layer piezoelectric body 111b. Then, the polarization direction (− direction) is directed from the front surface 111bA to the back surface 111bB, and further, in the third layer piezoelectric body 111c, the polarization direction (+ direction) is directed from the back surface 111cB to the front surface 111cA. That is, the polarization direction becomes + − + along the thickness direction of the piezoelectric body.
Further, in the region Q adjacent to the region P, the polarization direction is opposite to that of the region P, and becomes − + − along the thickness direction of the piezoelectric body.

  In the electrode and polarization configuration as described above, the number of single-layer piezoelectric bodies 111 in the piezoelectric body 11 is an odd number. That is, since the polarization direction of the first layer is the same as the polarization direction of the final layer, the number of single-layer piezoelectric bodies 111 is an odd number.

  The electrode pattern on the bonding surface side of the odd-numbered layer and the electrode pattern on the anti-bonding surface side of the even-numbered layer are the same electrode pattern, and the electrode pattern on the bonding surface side of the even-numbered layer and the anti-bonding surface side of the odd-numbered layer number The electrode pattern is the same electrode pattern.

  That is, the electrode patterns on the back surfaces 111aB and 111cB of the odd layers (the first layer piezoelectric body 111a and the third layer piezoelectric body 111c in the present embodiment) and the surface 111bA of the even layer (the second layer piezoelectric body 111b in the present embodiment) are It will be the same. In this embodiment, these surfaces are divided into two drive signal phases (A phase and B phase) along the circumferential direction, and in each phase, every half wavelength alternately as shown in the figure. The application electrode pattern 16 is arranged so that it is polarized and an interval of ¼ wavelength is left between the A phase and the B phase.

  Further, the electrode patterns of the front surfaces 111aA and 111cA of the odd-numbered layers (first layer piezoelectric body 111a and third-layer piezoelectric body 111c in this embodiment) and the back surface 111bB of even-numbered layers (second layer piezoelectric body 111b in the present embodiment) are It will be the same. In the present embodiment, not the divided application electrode pattern 16 but a common electrode pattern 19 of two drive signal phases (A phase and B phase) is formed.

In this embodiment, for simplicity of explanation, three layers are used as an example. However, if the number of layers is five, seven, nine,.
Further, although the wave number of the traveling wave has been described as four waves, any wave number such as five waves, six waves, seven waves, etc. may be used.

As shown in FIG. 5 described above, the multilayer piezoelectric body 11 of the present embodiment is an elastic body in which the back surface 111cB of the third layer piezoelectric body 111c is the back surface (common electrode pattern 19 side) 11B as the multilayer piezoelectric body 11 as a whole. 12 is joined.
Further, the surface 111aA of the first layer piezoelectric body 111a becomes the surface 11A of the laminated piezoelectric body 11 as a whole, and the FPC 14 is joined so that a drive signal can be supplied.

As shown in FIG. 6, the electrode pattern and the polarization direction of each layer are configured, and as shown in FIG. 4 (a), the conductive portion 18a is extended to the outer peripheral side surface to make each electrode pattern conductive.
FIG. 7 is a diagram showing expansion and contraction of the piezoelectric body 11 due to the applied voltage. When the drive signal is applied to +, the A-phase and B-phase electrodes are alternately extended and contracted as shown in FIG. That is, the region P is extended and the region Q is reduced.

  On the other hand, when the drive signal is applied to-, contrary to the above, each electrode is alternately extended and reduced as shown in FIG. That is, the area P is reduced and the area Q is distracted.

  Thus, the configuration of the present embodiment exhibits the same behavior as the conventional single-phase piezoelectric body 11 in the applied voltage and the expansion / contraction direction.

The magnitude of expansion / contraction (deformation) in the piezoelectric body varies depending on the strength of the electric field generated inside the piezoelectric body. That is, if the applied voltage is the same, the thinner the piezoelectric body, the stronger the electric field.
Therefore, it is better that the piezoelectric body is thin. However, if the single-layer piezoelectric body is thin, the strength is insufficient. However, according to the present embodiment, the strength can be ensured by stacking even if the thickness of the single-layer piezoelectric body is reduced.

  Since each single-layer piezoelectric body can be made thin, a large amount of deformation can be obtained without increasing the applied voltage so much. That is, a practical amount of deformation can be ensured without using a booster circuit or the like.

  Furthermore, the single-layer piezoelectric bodies 111 having the same electrode pattern are alternately arranged in different directions during lamination. That is, the laminated piezoelectric material is formed by the single-layer piezoelectric material 111 having the same electrode pattern without using the single-layer piezoelectric material having different electrode patterns. For this reason, it is possible to reduce costs, simplify the manufacturing process, reduce operational errors, and improve yield and quality of piezoelectric characteristics.

  According to this embodiment, since the single-layer piezoelectric body 111 is laminated and each layer is made conductive by the conducting portion 18a, it is possible to simultaneously polarize all the single-layer piezoelectric bodies 111 with one applied voltage.

  Thus, according to the present embodiment, when the vibration wave motor 1 is assembled, the drive voltage can be lowered as compared with the conventional case, and the performance of the vibration wave motor 1 such as drive efficiency and generated torque can be improved. became.

  This embodiment has a great effect on driving performance of the small-diameter type traveling wave type vibration wave motor 1 in which the driving voltage increases. In particular, when the outer diameter is 25 mm or less, the effect of this embodiment is remarkable.

Further, in order to obtain a wavelength, the small-diameter type traveling wave type vibration wave motor 1 needs to reduce the number of waves to 4 waves and 5 waves, but if the number of waves is reduced, the number of electrode patterns of the A phase and the B phase is reduced. There are fewer issues.
In the case of four waves in the present embodiment, the number of electrode patterns of A phase (or B phase) is 4, and in the case of five waves, the number of electrode patterns of A phase (or B phase) is 5, but the electrodes of each phase When the number of patterns is small, bending vibration is difficult to be excited.

  Therefore, as in the present embodiment, each piezoelectric body 11 layer needs to be polarized so that piezoelectric characteristics can be obtained. In the present invention, the effect is particularly obtained when the number of traveling waves is four or five.

(Second embodiment)
FIG. 8 is a diagram illustrating a lens barrel 200 according to the second embodiment of the present invention. The present invention can be configured not only in the piezoelectric body 11 of the small-diameter type vibration wave motor 1 of the first embodiment but also in the piezoelectric body 11 of the large-diameter ring-type vibration wave motor 210. The same effect as that of the embodiment can be obtained.

First, the configuration of the vibration wave motor 210 will be described.
The vibrator 211 includes a piezoelectric body 11 and an elastic body 214 joined with the piezoelectric body 11. The traveling wave is generated in the vibrator 211. In the present embodiment, the traveling wave is described as 9 traveling waves as an example.
The elastic body 214 is made of a metal material having a high resonance sharpness and has an annular shape. A groove is cut on the opposite surface to which the piezoelectric body 11 is bonded, and the surface of the portion where the groove is not provided becomes the driving surface 216a and is brought into pressure contact with the moving element 220. The surface of the driving surface 216a of the elastic body 214 is provided with a lubricating coating film for ensuring driving performance and improving durability.

  The piezoelectric body 11 is divided into two phases (A phase and B phase) along the circumferential direction, and in each phase, elements with alternating polarization for each half wavelength are arranged. An interval of 1/4 wavelength is provided between the A phase and the B phase.

A non-woven fabric 252 and a pressure member 250 are disposed under the piezoelectric body 11.
The nonwoven fabric 252 is an example of felt, and is disposed under the piezoelectric body 11 so as not to transmit the vibration of the vibrator 211 to the pressure member 250.

  The pressure member 250 is disposed under a pressure plate (not shown) and generates pressure. In the present embodiment, a coil spring or a wave spring may be used instead of a disc spring in which the pressure member 250 is a disc spring. The pressure member 250 is held by the pressing ring 251 being fixed to the fixing member 223.

The mover 220 is made of a light metal such as aluminum, and a sliding material for improving wear resistance is provided on the surface of the sliding surface.
On the moving element 220, a vibration absorbing member 243 such as rubber is arranged to absorb the vertical vibration of the moving element 220, and an output transmission member 242 is arranged thereon.

The output transmission member 242 regulates the pressurization direction and the radial direction by a bearing 253 provided on the fixed member 223, thereby regulating the pressurization direction and the radial direction of the moving element 220. .
The output transmission member 242 has a protrusion 241 from which a fork connected to the cam ring 315 is engaged, and the cam ring 315 is rotated with the rotation of the output transmission member 242.

In the cam ring 315, a key groove 317 is cut obliquely in the cam ring 315, and a fixing pin 318 provided in the AF ring 319 is engaged with the key groove 317 so that the cam ring 315 is rotationally driven. As a result, the AF ring 319 is driven in the straight direction in the optical axis direction, and can be stopped at a desired position.
In the fixing member 223, the pressing ring 251 is attached with a screw, and by attaching this, the output transmission member 242, the moving element 220, the vibrator 211, and the pressing member 250 can be configured as one motor unit.

The piezoelectric body 213 of the second embodiment is also a laminated piezoelectric body similar to the piezoelectric body 11 of the first embodiment.
That is, a single-layer piezoelectric body is laminated by a plurality of layers (three layers in this embodiment). The first-layer piezoelectric body, the second-layer piezoelectric body, and the third-layer piezoelectric body are arranged in this order from the side opposite to the adhesive surface of the laminated piezoelectric body with the elastic body.

And the electrode is arrange | positioned at the surface side of the 1st layer piezoelectric material, and it is divided into the phase (A phase, B phase) of two drive signals along the circumferential direction. In each phase, the electrodes are arranged so that they are alternately polarized every ½ wavelength, and an interval of ¼ wavelength is left between the A phase and the B phase.
On the back surface of the first-layer piezoelectric body, not a divided electrode pattern, but a common electrode pattern of two drive signal phases (A phase and B phase) is formed.

On the surface of the second layer piezoelectric body, not a divided electrode pattern but a common electrode pattern of two drive signal phases (A phase and B phase) is formed. The surface of the second layer and the back surface B of the first layer are bonded together.
An electrode is disposed on the back surface side of the second layer piezoelectric body, and is divided into two drive signal phases (A phase and B phase) along the circumferential direction. In each phase, the electrodes 16 are arranged so that they are alternately polarized every ½ wavelength, and an interval of ¼ wavelength is left between the A phase and the B phase.

Electrodes are arranged on the surface of the third-layer piezoelectric body, which is divided into two drive signal phases (A phase and B phase) along the circumferential direction. In each phase, the electrodes are arranged so that they are alternately polarized every ½ wavelength, and an interval of ¼ wavelength is left between the A phase and the B phase. The back surface of the second layer piezoelectric body and the surface of the third layer piezoelectric body are bonded together.
On the back surface of the third layer piezoelectric body, not a divided electrode pattern, but a common electrode pattern of two drive signal phases (A phase, B phase) is formed.
As described above, the second embodiment also has the same effect as the first embodiment.

  1: vibration wave motor, 10: vibrator, 11: piezoelectric body, laminated piezoelectric body, 11A: front surface, 11B: back surface, 12: elastic body, 16: electrode, 18: adhesive, 18a: extension part, 20: movement 110, lens barrel, 111: single layer piezoelectric body, 111a: first layer piezoelectric body, 111aA: front surface, 111aB: back surface, 111b: second layer piezoelectric body, 111bA: front surface, 111bB: back surface, 111bB: back surface 111c: third layer piezoelectric body, 111cA: front surface, 111cB: back surface, 200: lens barrel, 210: vibration wave motor, 211: vibrator, 213: piezoelectric body, 214: elastic body, 220: moving element

Claims (4)

  A first electrode pattern is formed on one surface, a second electrode pattern in which a drive signal having a first phase is input to the other surface, and a third signal in which a drive signal having a phase different from the first phase is input. An electromechanical transducer laminated body in which the first electromechanical transducer formed with the electrode pattern and the fourth electrode pattern is laminated so that the surfaces having the same electrode pattern face each other;
  An elastic body in contact with the electromechanical transducer stack,
  A relative movement member driven by the elastic body,
  The electromechanical transducer stack includes a first electromechanical transducer and a second electromechanical transducer that is inverted with a target axis having a part of the fourth electrode pattern of the first electromechanical transducer as a target line. A vibration wave motor in which elements are stacked. The vibration wave motor according to claim 1,
The number of stacked layers of the first electromechanical transducer and the second electromechanical transducer is an odd number;
Vibration wave motor characterized by The vibration wave motor according to claim 1 or 2,
The same electrode pattern is formed on the surfaces of the first electromechanical transducer and the second electromechanical transducer facing each other,
Being conducted by a conduction portion extending from the side surface of the electromechanical transducer stack.
Vibration wave motor characterized by In the vibration wave motor according to any one of claims 1 to 3,
The first electromechanical conversion element and the second electromechanical conversion element are in two groups, and the polarization directions of the adjacent first electromechanical conversion element and the second electromechanical conversion element are opposite to each other. That
Vibration wave motor characterized by

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