Vibration drive device capable of generating click feeling and image pickup apparatus

Patent metadata

Field	Value
Publication number	US-10419653-B2
Application number	US-201615180440-A
Country	US
Kind code	B2
Filing date	Jun 13, 2016
Priority date	Jun 19, 2015
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

A vibration drive device giving an appropriate click feeling when an operation member driven by a vibration actuator is manually operated. A controller applies, to a piezoelectric element, a drive signal for exciting, in an elastic body joined to the piezoelectric element, only a first vibration perpendicular to a contact surface between the elastic body and a driven element, or the first vibration and a second vibration parallel to the contact surface. When the position of the operation member is outside a driving section, only the first vibration is excited, whereas when within the driving section, the first vibration and the second vibration are excited so as to make the position closer to a target position set within the driving section. Application of the drive signal is stopped when the position is in a section in the driving section for a predetermined time period.

First claim

What is claimed is:

1. A vibration drive device comprising:
a vibration actuator including:
a vibration element including an electromechanical energy conversion element, and an elastic body joined to said electromechanical energy conversion element, and
a driven element that is in pressure contact with said elastic body;

a position detection unit configured to detect a relative position between said vibration element and said driven element; and
a controller that applies a drive signal, for exciting vibration in said elastic body, to said electromechanical energy conversion element to control driving of said elastic body of said vibration actuator,
wherein in a case where the relative position is outside a first section, said controller performs control to excite in said elastic body a first vibration in a direction perpendicular to a contact surface between said elastic body and said driven element, whereas in a case where the relative position is within the first section, said controller performs control to excite said elastic body so as to make the relative position closer to a target position set within the first section and performs control to excite said elastic body strongly toward a position farther away from the target position.

2. The vibration drive device according to claim 1 , wherein the first section includes a second section including the target position, and
wherein in a case where the relative position is within the second section, said controller excites the first vibration in said elastic body by applying the drive signal.

3. The vibration drive device according to claim 1 , further comprising a target position-setting unit configured to set the target position.

4. The vibration drive device according to claim 1 , further comprising a section setting unit configured to set a section, in which said controller excites the first vibration in said elastic body by the drive signal, between each of two adjacent sections of a plurality of the first sections.

5. The vibration drive device according to claim 1 , wherein the vibration includes the first vibration and a second vibration parallel to the contact surface in said elastic body, and
said controller changes an amplitude value of the first vibration or an amplitude value of the second vibration.

6. The vibration drive device according to claim 1 , further comprising a determination unit configured to determine whether or not the relative position is within the first section.

7. The vibration drive device according to claim 1 , wherein the vibration includes the first vibration and a second vibration parallel to the contact surface in said elastic body,
the vibration drive device further comprises an amplitude detection unit configured to detect an amplitude of the first vibration or an amplitude of the second vibration excited in said elastic body, and
said controller controls an amplitude of the drive signal based on the amplitude detected by said amplitude detection unit.

8. The vibration drive device according to claim 1 , wherein said controller changes a magnitude of a driving force for moving said vibration element and said driven element relative to each other, by applying the drive signal in which one of a frequency, a voltage, and a phase difference is controlled.

9. The vibration drive device according to claim 1 , wherein the first section includes a second section including the target position, and
wherein said controller stops applying the drive signal to said electromechanical energy conversion element when the relative position is within the second section for a predetermined time period including zero time.

10. The vibration drive device according to claim 9 , wherein the second section includes a third section including the target position, and
wherein in a case where the relative position is within the third section, said controller excites the first vibration in said elastic body by the drive signal.

11. The vibration drive device according to claim 9 , further comprising a determination unit configured to determine whether or not the relative position is within the second section, and
wherein when said determination unit determines that the relative position is within the second section, said controller stops applying the drive signal to said electromechanical energy conversion element.

12. The vibration drive device according to claim 1 , wherein in a case where the relative position is within the first section, said controller controls the vibration actuator such that a direction of frictional driving forces generated by the vibration actuator depends on which side of the target position the relative position is located.

13. An image pickup apparatus comprising:
a vibration drive device including a vibration actuator,
said vibration actuator including:
a vibration element including an electromechanical energy conversion element, and an elastic body joined to said electromechanical energy conversion element, and
a driven element that is in pressure contact with said elastic body; and

an operation member that is directly or indirectly joined to said vibration actuator included in said vibration drive device, and is driven by said vibration actuator,
said vibration drive device further including:
a position detection unit configured to detect a relative position between said vibration element and said driven element, and
a controller that applies a drive signal, for exciting vibration in said elastic body, to said electromechanical energy conversion element to control driving of said elastic body of said vibration actuator,

wherein in a case where the relative position is outside a first section, said controller performs control to excite in said elastic body a first vibration in a direction perpendicular to a contact surface between said elastic body and said driven element, whereas in a case where the relative position is within the first section, said controller performs control to excite said elastic body so as to make the relative position closer to a target position set within the first section and performs control to excite said elastic body strongly toward a position farther away from the target position.

14. The image pickup apparatus according to claim 13 , further comprising a switch that generates a signal for allowing manual operation of said operation member by reducing a frictional holding force acting between said elastic body and said driven element forming said vibration actuator, and
wherein when said switch is turned on, said controller applies the drive signal for exciting the first vibration in said elastic body to said electromechanical energy conversion element.

15. The image pickup apparatus according to claim 13 , wherein said operation member has an annular shape, and is arranged in a manner surrounding a photographic optical system included in the image pickup apparatus, about an optical axis, and
wherein a photographing mode or a photographing parameter is set by a manual operation for rotating said operation member about the optical axis.

16. A vibration drive device comprising:
a vibration actuator including:
a vibration element including an electromechanical energy conversion element, and an elastic body joined to said electromechanical energy conversion element, and
a driven element being in contact with said elastic body;

a position detection unit configured to detect a relative position between said vibration element and said driven element; and
a controller that applies a drive signal, for exciting vibration in said elastic body, to sai

Assignees

• Canon Kk

Inventors

• Onuma Kazufumi

Classifications

• H02N2/142

  Small signal circuits; Means for controlling position or derived quantities, e.g. speed, torque, starting, stopping, reversing · CPC title

• H04N23/57 Primary

  Mechanical or electrical details of cameras or camera modules specially adapted for being embedded in other devices · CPC title

• H04N23/54

  Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils · CPC title

• H02N2/0015 Primary

  using only bending modes · CPC title

• H02N2/16

  using travelling waves {, i.e. Rayleigh surface waves} · CPC title