阅读说明：本技术 振动型致动器及振动型致动器的制造方法 (Vibration-type actuator and method for manufacturing vibration-type actuator ) 是由 木村笃史 于 2020-01-14 设计创作，主要内容包括：本发明涉及振动型致动器及振动型致动器的制造方法。一种振动型致动器,包括在第一方向上彼此接触的振动元件和接触元件。振动元件的振动包括在第一方向上的第一振动模式下的振动和在与第一方向相交的第二方向上的第二振动模式下的振动。在振动元件中,第二振动模式下的共振频率的最小值大于或等于第一振动模式下的共振频率的最大值,并且第二振动模式下的共振频率的最大值和最小值之差与第二模式下的共振频率的最小值的比率小于或等于预先确定的值。(The present invention relates to a vibration-type actuator and a method of manufacturing the vibration-type actuator. A vibration-type actuator includes a vibration element and a contact element that contact each other in a first direction. The vibration of the vibration element includes a vibration in a first vibration mode in a first direction and a vibration in a second vibration mode in a second direction intersecting the first direction. In the vibration element, a minimum value of the resonance frequency in the second vibration mode is greater than or equal to a maximum value of the resonance frequency in the first vibration mode, and a ratio of a difference between the maximum value and the minimum value of the resonance frequency in the second vibration mode to the minimum value of the resonance frequency in the second mode is less than or equal to a predetermined value.)

1. A vibration-type actuator, comprising:

a plurality of vibrating elements; and

a contact member contacting the contact portions of the plurality of vibration members,

wherein vibrations excited in each of the plurality of vibrating elements cause relative movement of the plurality of vibrating elements and the contact element,

wherein the vibration includes vibration in a first vibration mode in which the contact portion is displaced in a first direction in which one of the plurality of vibration elements and the contact element are brought into pressure contact with each other, and vibration in a second vibration mode in which the contact portion is displaced in a second direction intersecting the first direction, and

wherein, among the plurality of vibration elements, a minimum value of the resonance frequency in the second vibration mode is greater than or equal to a maximum value of the resonance frequency in the first vibration mode, and a ratio of a difference between the maximum value and the minimum value of the resonance frequency in the second vibration mode to the minimum value of the resonance frequency in the second vibration mode is less than or equal to a predetermined value.

2. The vibration-type actuator of claim 1, wherein the predetermined value is 0.01.

3. The vibration-type actuator of claim 1,

wherein each of the plurality of vibration elements has an electro-mechanical energy conversion element and an elastic element joined to the electro-mechanical energy conversion element,

wherein the elastic member has a protrusion protruding in the first direction on a surface of the elastic member opposite to a surface to which the electro-mechanical energy conversion member is bonded, an

Wherein the protrusion has a sidewall portion forming a hollow structure and a contact portion contacting the contact member.

4. The vibration-type actuator of claim 1 wherein the second direction is orthogonal to the first direction.

5. The vibration-type actuator of claim 1, wherein the first vibration mode has an order of 1 and the second vibration mode has an order of 2.

6. A lens barrel, characterized by comprising:

the vibration-type actuator according to any one of claims 1 to 5; and

and a lens driven by the vibration-type actuator.

7. An image pickup apparatus characterized by comprising:

the vibration-type actuator according to any one of claims 1 to 5;

a lens driven by a vibration-type actuator; and

and an image pickup element disposed at a position where the light having passed through the lens is imaged.

8. An electronic device, comprising:

the vibration-type actuator according to any one of claims 1 to 5; and

and a driven member driven by the vibration-type actuator.

9. A manufacturing method of a vibration-type actuator, characterized by comprising a plurality of vibration elements and a contact element that is in contact with contact portions of the plurality of vibration elements, such that vibration excited in each of the plurality of vibration elements causes relative movement of the plurality of vibration elements and the contact element, and the vibration includes vibration in a first vibration mode in which the contact portion is displaced in a first direction in which one of the plurality of vibration elements and the contact element are brought into pressure contact with each other, and vibration in a second vibration mode in which the contact portion is displaced in a second direction that intersects the first direction, the manufacturing method comprising:

attaching a vibrating element to the feeding substrate;

measuring a plurality of resonance frequencies of a vibrating element including a first vibration mode and a second vibration mode;

classifying the vibration elements into one of a plurality of groups such that, within each group of vibration elements, a minimum value of the resonance frequency in the second vibration mode is greater than or equal to a maximum value of the resonance frequency in the first vibration mode, and a ratio of a difference between the maximum value and the minimum value of the resonance frequency in the second vibration mode to the minimum value of the resonance frequency in the second vibration mode is less than or equal to a first predetermined value; and

the plurality of vibratory elements are selected from a single group.

10. The vibration-type actuator manufacturing method of claim 9, wherein the first predetermined value is 0.01.

11. The vibration-type actuator manufacturing method of claim 9, further comprising:

waiting a period of time after the attaching, wherein the period of time elapses before a resonance frequency of the vibrating element becomes constant and after a temperature of the vibrating element reaches a room temperature,

wherein, when categorizing, the vibratory elements are categorized into groups such that: within each group, the ratio of the difference between the maximum value and the minimum value of the resonance frequency in the second vibration mode to the minimum value of the resonance frequency in the second vibration mode is less than or equal to a second predetermined value that is less than the first predetermined value.

12. The method of manufacturing a vibration-type actuator according to claim 11, wherein the second predetermined value is 0.007.

13. The method of manufacturing a vibration-type actuator according to claim 9, wherein the second direction is orthogonal to the first direction.

14. The method of manufacturing a vibration-type actuator according to claim 9, wherein the first vibration mode has an order of 1, and the second vibration mode has an order of 2.

Technical Field

The present disclosure relates to a vibration-type actuator.

Background

Conventionally, a vibration type actuator has been proposed. The vibration-type actuator is configured such that a contact element in contact with a vibration element (elastic element, piezoelectric element) is driven by vibration excited by the vibration element (the vibration element and the contact element are relatively moved).

For example, japanese patent application publication No.2011-259559 discloses an actuator including two vibrating elements or a plurality of vibrating elements. The two vibrating elements are driven linearly or the plurality of vibrating elements are driven rotationally.

However, in the vibration element, the resonance frequency varies due to the dimensional changes of the elastic element and the piezoelectric element. Therefore, in the case where one contact element is driven by a plurality of vibrating elements using one voltage boosting circuit (i.e., common alternating current signal), the performance of the actuator may be degraded in some cases depending on the combination of the vibrating elements.

Disclosure of Invention

The present disclosure is directed to a technique of reducing performance degradation caused by variations in resonance frequencies of a plurality of vibration elements disposed in a vibration-type actuator.

According to an aspect of the present disclosure, a vibration-type actuator includes: a plurality of vibrating elements; and a contact member that is in contact with the contact portions of the plurality of vibration members, and the vibration excited in each of the plurality of vibration members causes relative movement of the plurality of vibration members and the contact member. The vibration includes vibration in a first vibration mode in which the contact portion is displaced in a first direction in which one of the plurality of vibration elements and the contact element are brought into pressure contact with each other, and vibration in a second vibration mode in which the contact portion is displaced in a second direction intersecting the first direction. In the plurality of vibration elements, a minimum value of the resonance frequency in the second vibration mode is greater than or equal to a maximum value of the resonance frequency in the first vibration mode, and a ratio of a difference between the maximum value and the minimum value of the resonance frequency in the second vibration mode to the minimum value of the resonance frequency in the second mode is less than or equal to a predetermined value.

Other features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

Drawings

Fig. 1A is an overall perspective view illustrating exploded components of a rotary actuator according to an exemplary embodiment. Fig. 1B is an enlarged and expanded perspective view illustrating the periphery of a vibration element according to an exemplary embodiment.

Fig. 2 is a block diagram illustrating a configuration of a drive control apparatus of a rotary actuator according to an exemplary embodiment.

Fig. 3A is a graph illustrating impedance characteristics of respective vibration elements according to an exemplary embodiment. Fig. 3B is a graph illustrating a relationship between changes in the second resonance frequency of three vibration elements and motor performance according to an exemplary embodiment (horizontal axis; difference in resonance frequency in the second vibration mode). Fig. 3C is a graph illustrating the relationship between the change in the second resonance frequency of the three vibration elements and the motor performance according to the exemplary embodiment (horizontal axis; ratio of the difference between the maximum value and the minimum value of the resonance frequency in the second vibration mode to the minimum value of the resonance frequency in the second vibration mode).

Fig. 4 is a flowchart regarding steps of manufacturing a vibration-type actuator according to an exemplary embodiment.

Fig. 5 is a flowchart regarding a variation example of the steps of manufacturing the vibration-type actuator according to the exemplary embodiment.

Fig. 6 is a graph illustrating a change in resonance frequency after flexible (flex) engagement of a vibration element according to an exemplary embodiment.

Fig. 7A and 7B are a top view and a block diagram respectively illustrating a schematic configuration of an image pickup apparatus having a vibration-type actuator according to an exemplary embodiment.

Fig. 8A and 8B are a plan view and a side view illustrating the configuration of the vibration element, respectively.

Fig. 9A is an explanatory diagram illustrating a vibration mode of the vibration element. Fig. 9B and 9C are explanatory diagrams each illustrating a first vibration mode and a second vibration mode of the vibration element.

Detailed Description

First, a conventional technique is described with reference to fig. 8A to 9C.

Fig. 8A is a plan view of the vibration element, and fig. 8B is a side view of the vibration element. In fig. 8A and 8B, a vibration element 1 includes an electro-mechanical energy conversion element (piezoelectric element) 3 having a rectangular (quadrangular) sheet shape and an elastic element 2 integrally bonded to (one plane of) the piezoelectric element 3.

The elastic element 2 comprises a main part 2-3 and a support part 2-4.

The main portion 2-3 comprises a base portion 2-1 and two protrusions 2-2. The base portion 2-1 having a rectangular thin plate shape vibrates together with the piezoelectric element 3. The protrusion 2-2 protrudes from one plane of the base portion 2-1 (a plane of the elastic element 2 opposite to a plane to which the piezoelectric element 3 is bonded). For example, as discussed in Japanese patent application laid-open No.2011-234608, the protrusions 2-2 each include a sidewall portion 2-2-1 and a contact portion 2-2-2. The side wall portion 2-2-1 protrudes from one plane of the base portion 2-1 in a direction (first direction) of pressure contact with the contact member and has a hollow (continuous) structure. The contact portion 2-2-2 is at the front edge of each projection 2-2 and is in contact with the contact element.

The support portions 2-4 are each flexible and structurally integral with the main portion 2-3. The support sections 2-4 each have a thin section 2-5, and the thin sections 2-5 are constituted by partially thinning each support section 2-4 so that the vibration of the main section 2-3 is not transmitted to the outside as much as possible. In addition, the support portions 2 to 4 have circular holes 2 to 6 and elongated holes 2 to 7, respectively, for positioning at the time of bonding the piezoelectric element 3 and assembling the vibration element. Hereinafter, the Z direction is defined as a direction in pressure contact with the vibration element and the contact element, the X direction is defined as a direction in which the vibration element and the contact element relatively move, and the Y direction is defined as a direction perpendicular to the X direction and the Z direction, respectively.

As shown in fig. 9A, the vibration element 1 causes a first bending motion in the short direction (Y). The first bending motion mainly displaces the front edge of the projection 2-2 in the Z-direction (first direction). In addition, the vibrating element 1 causes a second bending motion in the longitudinal direction (X). The second bending motion mainly displaces the front edge of the projection 2-2 in a direction including an X-direction component (a direction intersecting the first direction: hereinafter referred to as "second direction"). At this time, the first bending motion and the second bending motion are generated to have a time phase difference. Thus, the front edges of the projections 2-2 each make an elliptic motion, and as shown in fig. 9A, a contact member, not shown, is driven in the X direction. Herein, the "direction intersecting with the first direction" (second direction) also includes "a direction orthogonal to the first direction". Fig. 9B also illustrates a first bending motion (first vibration mode or mode 1). In addition, fig. 9C also illustrates a second bending motion (second vibration mode or mode 2). Herein, the order (first order) of the first vibration mode shown in fig. 9A and 9B is 1, and the order (second order) of the second vibration mode shown in fig. 9A and 9C is 2. The order means the number of antinodes of vibration.

Exemplary embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In the present exemplary embodiment, the vibration-type actuator includes a vibration element to which vibration is excited, and a contact element that is in pressure contact with the vibration element. The vibration element and the contact element perform relative movement by vibration. That is, the vibration-type actuator is configured such that the drive output from the vibration element can be taken out (take out) by the relative movement of the vibration element and the contact element.

Fig. 1A and 1B illustrate a first exemplary embodiment of the present disclosure.

Fig. 1A is a perspective view illustrating exploded parts of a rotary actuator having three (a plurality of) vibration elements shown in fig. 8A and 8B (of a vibration-type actuator) disposed on the circumference. Fig. 1B is an enlarged and expanded perspective view illustrating the periphery of the vibration element 1.

As shown in fig. 1A, three (a plurality of) vibration elements 1 are disposed on a circular base (support member) 7 to rotationally drive a rotor (contact element) 8 in contact with the vibration elements 1.

Each vibration element 1 is held to a small base (holding member 4) by fitting pins 4a of the holding member 4 into circular holes 2-6 and elongated holes 2-7 of the support portion, respectively, and engaging them. In addition, the holding member 4 is positioned to be movable in the pressing direction by fitting the pins 7a of the support member 7 into the holes 4b, respectively.

A rectangular through hole 4c is provided to the holding member 4, and a pressing member 6 that presses each vibration element 1 is fitted into the through hole 4 c. When the pressing member 6 contacts the supporting member 7, an unillustrated pressing member (such as a spring) causes the pressing member 6 to press the vibrating element 1 via the vibration isolating member 5 (such as a felt). In addition, the pressing member 6 is relatively movable in the pressing direction with respect to the holding member 4.

This configuration makes it difficult for the support portions 2 to 4 to receive the reaction force generated at the time of pressurization, thereby preventing the bonding of the piezoelectric elements from being peeled off. A flexible printed circuit board (feeding substrate) 33 that feeds electric power is joined to the electric energy-mechanical energy conversion element (piezoelectric element) 3. An alternating signal is applied to the piezoelectric element 3 via the feed substrate 33 to drive the vibration element 1.

The positioning pins 6a and 6b are disposed on the pressing member 6. The pressing member 6 is positioned by fitting positioning pins 6a and 6b into holes 7b and 7c disposed on the support member 7, respectively. In addition, the pressing member 6 is in contact with a semi-cylindrical surface (protruding portion) 7d of the support member 7 so as to be rotatable in the pitch direction (direction of relative movement with respect to the contact element 8).

Fig. 2 is a block diagram illustrating the configuration of the drive control apparatus of the rotary actuator shown in fig. 1A and 1B. The drive control apparatus includes a position command generation unit 11, and the position command generation unit 11 generates a target value of the driven element 9 that is driven integrally with the contact element 8. The output side of the position command generating unit 11 is connected to the operation amount determining unit 16 via the comparing unit 12. The comparison unit 12 compares the target value output from the position command generation unit 11 with the current position of the driven element 9 output from the position detection unit 10. The operation amount determination unit 16 calculates the operation amount of the vibration-type actuator based on the comparison result of the comparison unit 12. The operation amount determination unit 16 is a proportional-integral (PI) controller or a proportional-integral-derivative (PID) controller.

The position detection unit 10 (e.g., an encoder) detects the position of the driven element 9. The vibrating elements a, b, and c, which are the above-described three vibrating elements 1 shown in fig. 1A, integrally drive the contact element 8 and the driven element 9. The output side of the operation amount determination unit 16 is connected to the ellipticity determination unit 13 and the drive frequency determination unit 14. The ellipticity determining unit 13 sets the ellipticity of the elliptical motion. The driving frequency determination unit 14 sets the frequency of the alternating current signal.

The ellipticity determining unit 13 sets the ratio between the X-axis amplitude and the Z-axis amplitude of the elliptical motion generated on the protrusion (contact portion) of each vibrating element 1 based on the output from the operation amount determining unit 16. Thus, the ellipticity determining unit 13 may set the time phase difference of the two amplitude modes that achieve this ratio. The driving frequency determining unit 14 may set the driving frequency of the alternating voltage to be applied to each vibration element 1 based on the output from the operation amount determining unit 16. In addition, the output side of the ellipticity determining unit 13 and the output side of the driving frequency determining unit 14 are connected to the driving signal generating unit 15.

The drive signal generation unit 15 generates a two-phase alternating current signal having the frequency determined by the drive frequency determination unit 14 and the phase difference determined by the ellipticity determination unit 13. The output side of the drive signal generating unit 15 is connected to the booster circuit 17. The booster circuit 17 boosts the two-phase alternating current signal generated by the drive signal generating unit 15. The boosted two-phase alternating-current signals are applied in parallel to the three vibration elements 1 (vibration elements a, b, and c). The booster circuit 17 may be a power amplifier, a switching element, a Direct Current (DC) -Direct Current (DC) circuit, or a conversion circuit.

Fig. 3A illustrates an example of the impedance characteristics of the respective three vibration elements 1 (three lines indicate the impedance characteristics of different vibration elements, respectively). The horizontal axis represents the driving frequency, and the vertical axis represents the admittance (inverse of the impedance). The peak frequency of the admittance is the resonant frequency. One vibrating element 1 has two peaks which are the resonance frequency of the above-mentioned first bending motion (first vibration mode) and the resonance frequency of the second bending motion (second vibration mode). In the first bending motion, a shift is caused based on the first order number. In the second bending motion, a shift is caused based on the second step number. In the pressurized motor state, the two peaks tend to approach each other. Note that the first order "1" and the second order "2" are (have) orders desired in (the vibration-type actuator of) the vibration element 1 shown in fig. 8A and 8B. Thus, the first order and the second order are variable depending on the type of (vibration-type actuator having) the vibration element 1, and thus the order for performing the present disclosure is not limited to the order described herein.

In this example, in the plurality of (three) vibration elements 1, the displacement is caused based on the second order numberOf the second vibration mode of (2) is set to a maximum value f of the resonance frequency in the second vibration mode₂max (94.0kHz) and minimum f₂The difference between min (93.3kHz) was 0.7 kHz. That is, in the three vibration elements 1, the maximum value f of the resonance frequency in the second vibration mode in which the displacement is caused based on the second order number₂max and minimum value f₂min difference (0.7kHz) and minimum f₂The ratio of min (93.3kHz) (0.7/93.3) was 0.0075 (0.75%).

Fig. 3B illustrates an example of a measurement result representing a difference (f) in resonance frequency in the second vibration mode obtained in fig. 3A₂max-f₂min) and motor performance. The horizontal axis represents the difference between the maximum value and the minimum value of the resonance frequency in the second vibration mode. The vertical axis represents the power consumption at the maximum number of revolutions and the predetermined number of revolutions. Fig. 3C is a graph in which the horizontal axis of fig. 3B is replaced with a ratio of the difference between the maximum value and the minimum value of the resonance frequency in the second vibration mode to the minimum value of the resonance frequency in the second vibration mode.

The maximum rotation speed is 90rpm in order to prevent breakage of the vibration element 1. As shown in fig. 3B, the minimum value f of the resonance frequency in the second vibration mode₂maximum value f of resonance frequency in second vibration mode in plurality of vibration elements 1 having min of 90kHz₂max and minimum value f₂In the case where the difference in min exceeds 0.9kHz, power consumption tends to increase, and therefore, motor efficiency decreases. That is, the maximum value f of the resonance frequency in the second vibration mode among the plurality of vibration elements 1₂max and minimum value f₂Difference between min and minimum value f₂In the case where the ratio of min exceeds 0.01 (1%), power consumption tends to increase, and therefore motor efficiency (performance) decreases.

(see FIG. 3C)

Therefore, a plurality of vibration elements 1 are selected from the plurality of classified (classified) vibration elements 1 to be combined so that the maximum value f of the resonance frequency in the second vibration mode₂max and minimum value f₂Difference between min and minimum value f₂The ratio of min is less than or equal to 0.01 (1%). Accordingly, performance degradation due to a change in resonance frequency can be reduced, and thus a liquid crystal display device having the sameAn actuator with satisfactory performance. The details of the categorization will be described below.

In the second vibration mode, the performance of the actuator depends mainly on the amount of displacement in the X direction. The shift in the Z direction in the first vibration mode can be achieved by a certain amount, and therefore the shift amount does not need to exceed such a certain amount. Therefore, when driving using a plurality of vibration elements 1, attention is paid only to the resonance frequency in the second vibration mode.

The actuator is driven at a high frequency and the frequency is lowered to approach the resonant frequency in the second vibration mode. Thereby, the speed of the actuator is increased. Thus, if the resonance frequency in the second vibration mode is not higher than the resonance frequency in the first vibration mode, the vibration amplitude in the first vibration mode abruptly decreases out of the resonance frequency before the vibration amplitude in the second vibration mode becomes large. Therefore, satisfactory performance cannot be obtained.

Therefore, in the case of driving using a plurality of vibration elements 1, as shown in fig. 3A, the minimum value f of the resonance frequency in the second vibration mode₂min is set to be greater than or equal to the maximum value f of the resonance frequency in the first vibration mode₁max。

Regarding Δ f concerning the single vibration element 1, which is the difference (f2-f1) between the value f2 of the resonance frequency in the second vibration mode and the value f1 of the resonance frequency in the first vibration mode, Δ f is desirably greater than or equal to 0.5kHz and less than or equal to 5 kHz. If Δ f is less than 0.5kHz, there is a possibility that, when the vibration element 1 is driven in the vicinity of the resonance frequency in the second vibration mode, the driving frequency exceeds the resonance frequency in the first vibration mode and the vibration amplitude sharply decreases. On the other hand, if Δ f is larger than 5kHz, when the vibration element 1 is driven in the vicinity of the resonance frequency in the second vibration mode, the driving frequency is far from the resonance frequency in the first vibration mode and the vibration amplitude in the first vibration mode is difficult to become large.

Fig. 4 is a flowchart illustrating steps of manufacturing a vibration-type actuator according to an exemplary embodiment of the present disclosure.

As shown in fig. 4, in step S18, the piezoelectric element 3 is bonded to the elastic element, and in step S19, the flexible printed board (feeding substrate) 33 is bonded to the piezoelectric element 3. After steps S18 and S19, the resonance frequencies in the two vibration modes are measured by impedance measurement using the single vibration element 1 in step S20. Classification is performed within 1% of the classification range based on the measured resonance frequency in the second vibration mode.

The classification is to classify the plurality of vibration elements 1 into groups. For example, in the plurality of vibration elements 1, the minimum value f of the resonance frequency in the second vibration mode₂In the case where min is 100kHz, the ratio 0.01 (1%) is 1 kHz. Thus, for example, the vibration elements 1 in the range of equal to or more than 100kHz and less than 101kHz are classified into a first group, and the vibration elements 1 in the range of equal to or more than 101kHz and less than 102kHz are classified into a second group. In addition, the vibration elements in the range of equal to or more than 102kHz and less than 103kHz are classified into the third group.

In this classification at step S21, in the vibration element 1 in the group, the maximum value f of the resonance frequency in the second vibration mode₂max and minimum value f₂Difference between min and minimum value f₂The ratio of min may be set to a value less than or equal to 0.01 (1%). Therefore, in step S22, the vibration elements 1 are randomly selected within the group. In step S23, the engagement of the vibration element holding member is performed. In step S24, motor assembly is performed. In this way, a motor with satisfactory performance can be obtained.

Fig. 5 is a flowchart illustrating a variation example of the steps of manufacturing the vibration-type actuator according to an exemplary embodiment of the present disclosure. This variation example may be used in certain situations at the production site. That is, when it is desired to shorten the time from the joining of the feed substrate 33 in step S19 to the measurement of the resonance frequency in step S120, the measurement of the resonance frequency in step S120 is performed a little after the joining of the feed substrate 33 in step S19 (the temperature of the vibrating element 1 is reliably room temperature).

However, as shown in fig. 6, the resonance frequency changes within 24 hours after the feeding substrate 33 has been joined. Therefore, a change in the amount of change in the resonance frequency before the resonance frequency becomes constant should be considered. Therefore, in the measurement of the resonance frequency in step S120, the range of classification in step S121 is narrowed and the ratio is less than or equal to 0.007 (0.7%).

Exemplary embodiments of the present disclosure have been described above in detail. However, the present disclosure is not limited to such specific exemplary embodiments, and variations are included in the present disclosure without departing from the scope of the present disclosure. For example, the vibration element 1 according to the exemplary embodiment of the present disclosure is not only applied to the rotary actuator shown in fig. 1A and 1B. For example, the vibration element 1 may also be applied to a linear actuator in which two vibration elements 1 are disposed in the driving direction or disposed on the upper surface and the lower surface of the contact element, respectively.

In addition, the vibration-type actuator according to the exemplary embodiment of the present disclosure can be applied to various uses, such as lens driving of an image pickup apparatus (optical device), rotational driving of a photosensitive drum in a copying machine, or driving of a table. Herein, as an example, an image pickup apparatus (optical device) in which a lens disposed in a lens barrel is driven using a vibration-type actuator having a plurality of vibration elements disposed in a ring shape that rotationally drives a contact element.

Fig. 7A is a top view illustrating a schematic configuration of an image pickup apparatus 700 as an electronic device.

The image pickup apparatus 700 includes a camera body 730 having an image pickup element 710 and a power button 720. The image pickup apparatus 700 further includes a lens barrel 740, the lens barrel 740 having a first lens group (not shown), a second lens group 320, a third lens group (not shown), a fourth lens group 340, and vibration-type actuators 620 and 640. The lens barrel 740 is detachable from the camera body 730 as an interchangeable lens.

In the image pickup apparatus 700, the vibration-type actuator 620 drives the second lens group 320 as a driven member. The vibration-type actuator 640 drives the fourth lens group 340 as a driven member. The vibration element 1 described with reference to fig. 1A to 7A is used in the vibration-type actuators 620 and 640. For example, the rotation of the contact elements constituting the vibration-type actuator 620 is converted into a linear motion in the optical axis direction by a gear, and the position of the second lens group 320 in the optical axis direction is adjusted. Almost the same for the vibration-type actuator 640.

Fig. 7B is a block diagram illustrating a schematic configuration of the image pickup apparatus 700. The first lens group 310, the second lens group 320, the third lens group 330, the fourth lens group 340, and the light amount adjustment unit 350 are disposed at predetermined positions on the optical axis within the lens barrel 740. The light passing through the first lens group 310 to the fourth lens group 340 and the light amount adjusting unit 350 is imaged on the image pickup element 710. The image pickup element 710 converts an optical image into an electric signal to be output. The output is transmitted to the camera processing circuit 750.

The camera processing circuit 750 amplifies or performs gamma correction on an output signal from the image pickup element 710. The camera processing circuit 750 is connected to a Central Processing Unit (CPU)790 via an Auto Exposure (AE) gate 755, and is also connected to the CPU 790 via an Auto Focus (AF) gate 760 and an AF signal processing circuit 765. The video signal that has been subjected to predetermined processing in the camera processing circuit 750 is transmitted to the CPU 790 via the AE gate 755, the AF gate 760, and the AF signal processing circuit 765. The AF signal processing circuit 765 extracts a high-frequency component of the video signal, generates an evaluation value signal for Auto Focus (AF), and supplies the generated evaluation value to the CPU 790.

The CPU 790, which is a control circuit that controls the overall operation of the image pickup apparatus 700, generates a control signal for determining exposure or focus based on the obtained video signal. The CPU 790 controls the driving of the vibration-type actuators 620 and 640 and the meter 630 so that a certain exposure and an appropriate focusing state can be obtained. Accordingly, the positions of the second lens group 320, the fourth lens group 340, and the light amount adjustment unit 350 in the optical axis direction are adjusted.

Under control using the CPU 790, the vibration-type actuator 620 moves the second lens group 320 in the optical axis direction, and the vibration-type actuator 640 moves the fourth lens group 340 in the optical axis direction. In addition, the meter 630 controls the driving of the light amount adjustment unit 350.

The position of the second lens group 320 driven by the vibration-type actuator 620 in the optical axis direction is detected by the first encoder 770. The detection result is notified to the CPU 790, and the CPU 790 then feeds back the detection result to the driving of the vibration-type actuator 620. In a similar manner, the position of the fourth lens group 340 in the optical axis direction, which is driven by the vibration-type actuator 640, is detected by the second encoder 775. The detected result is notified to the CPU 790, and the CPU 790 then feeds back the detected result to the driving of the vibration-type actuator 640.

The position of the light amount adjusting unit 350 in the optical axis direction is detected by the aperture encoder 780. The detected result is notified to the CPU 790, and the CPU 790 then feeds back the detected result to the driving of the meter 630.

The vibration-type actuators 620 and 640 are not limited to applications of driving the lens groups in the image pickup apparatus in the optical axis direction. The vibration-type actuators 620 and 640 may also be used for applications in which an image blur correction lens or an image pickup element is driven in a direction orthogonal to the optical axis to correct an image blur.

According to the present disclosure, in a vibration-type actuator having a plurality of vibration elements, performance degradation due to a variation in resonance frequency among the plurality of vibration elements can be reduced.

While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.