Controllably coupled piezoelectric motors

• US 8,351,104 B2
• Filed: 03/05/2009
• Issued: 01/08/2013
• Est. Priority Date: 03/06/2008
• Status: Active Grant

• Current Assignee: Nanomotion Limited (Johnson Electric Holdings Limited)
• Original Assignee: Nanomotion Limited (Johnson Electric Holdings Limited)
• Inventors: Peled, Gal, Karasikov, Nir, Zaifrani, Silvio, Eshed, Gal, Hasson, Shaul
• Primary Examiner(s): CHERRY, EUNCHA P
• Application Number:
  US12/398,216
• Publication Number:
  US 20090225388A1
• Time in Patent Office: 1,405 Days
• Field of Search: 3592231-2261, 310/236.16, 310/323.16, 310/328
• US Class Current: 359/225.1
• CPC Class Codes: B60R 1/072 for adjusting the mirror relative to its housing
• CPC Class Codes: G02B 7/1821 for rotating or oscillating mirrors
• CPC Class Codes: H02N 2/006 Elastic elements, e.g. springs in general F16F1/00
• CPC Class Codes: H02N 2/026 by pressing one or more vibrators against the driven body
• CPC Class Codes: H02N 2/108 around multiple axes of rotation, e.g. spherical rotor motors
• CPC Class Codes: H10N 30/202 using longitudinal or thickness displacement combined with bending, shear or torsion displacement
• CPC Class Codes: H10N 30/2023 having polygonal or rectangular shape

Abstract

A mirror system comprising: a mirror; at least one piezoelectric motor having a coupling surface for coupling the motor to a moveable body; at least one spherical contact surface coupled to the mirror; and a motor mounting frame that holds a piezoelectric motor of the at least one piezoelectric motor and presses the piezoelectric motor coupling surface to a contact surface of the spherical contact surface; wherein the motor is controllable to apply force to the contact surface that rotates the mirror.

Claims

1. A mirror system comprising:

a mirror;

a moveable body operably connected to the mirror;

a friction nub for controlling the motion and positioning of moveable body;

at least one piezoelectric motor operably couple-able to the friction nub and to the moveable body;

a motor mounting frame that holds a piezoelectric motor of the at least one piezoelectric motor; and

a coupling apparatus operably connected to the motor mounting frame, the coupling apparatus controllable and configured to provide different coupling forces to the moveable body and the coupling apparatus comprises a shape memory alloy connected to a power supply,

whereby the mirror is operably engaged or disengaged by controlling the temperature of the shape memory alloy with respect to a transition temperature of the alloy so that the mirror position can be adjusted by one of the at least one piezoelectric motors when the mirror is operably engaged and allowing movement of the mirror without substantial resistance when the mirror is disengaged.

2. A mirror system according to claim 1, further comprising a spherical contact plate coupled to the mirror wherein the spherical contact plate comprises a surface of a truncated sphere having a facet to which the mirror is fixed.

3. A mirror system according to claim 2 wherein the at least one piezoelectric motor comprises a first piezoelectric motor controllable to rotate the sphere about an axis through the center of the sphere and a second piezoelectric motor controllable to rotate first motor to rotate thereby the axis about which the first piezoelectric motor rotates the sphere.

4. A mirror system according to claim 2 wherein the at least one motor comprises a first piezoelectric motor coupled to the sphere controllable to rotate the sphere selectively about first and second orthogonal axes of rotation that pass through the center of the sphere.

5. A mirror system according to claim 1 wherein the at least one motor comprises first and second motors.

6. A mirror system according to claim 5 wherein the at least one coupling surface comprises first and second contact surfaces to which the contact surfaces of the first and second piezoelectric motors are respectively pressed.

7. A mirror system according to claim 6 and comprising a mirror mount having a first surface to which the mirror is mounted and at least one second surface to which the first and second contact surfaces are mounted.

8. A mirror system according to claim 7 wherein the first and second contact surfaces have a same center of curvature.

9. A mirror system according to claim 7 wherein the first and second contact surfaces have a same radius of curvature.

10. A mirror system according to claim 7 wherein the first motor is controllable to apply force to the first contact surface that rotates the mirror about a first axis and the second motor is controllable to apply force to the second contact surface that rotates the mirror about a second axis substantially orthogonal to the first axis.

11. A mirror system according to claim 7 and comprising a motor mount that fits inside the mirror mount and comprises first and second motor mounting frames that hold the first and second motors.

12. A mirror system according to claim 11 and comprising a ball joint that couples the motor mount to the mirror mount.

13. A mirror system according to claim 1 wherein the motor mounting frame comprises a coupling apparatus controllable to selectively provide different coupling forces for coupling the coupling surface of the piezoelectric motor to the contact surface.

14. A mirror system according to claim 13 wherein the coupling apparatus is controllable to determine coupling force magnitude to selectively engage the motor to, or disengage the motor from, the contact surface.

15. Apparatus comprising:

a moveable body having first and second positions;

a piezoelectric motor controllable to move the body from the first to the second position;

an element that stores potential energy whose potential energy increases when the piezoelectric motor moves the body from the first to the second positions; and

coupling apparatus controllable to decouple the motor from the body;

wherein the potential energy decreases and causes the body to return to the first position when the coupling apparatus decouples the motor from the body.

16. Apparatus according to claim 15 wherein the potential energy comprises mechanical potential energy.

17. Apparatus according to claim 16 wherein the element that stores potential energy is an elastic element.

18. Apparatus according to claim 16 wherein the mechanical potential energy comprises gravitational potential energy.

19. Apparatus according to claim 18 wherein the element that stores potential energy is a body whose gravitational potential energy increases when the body moves from the first to the second position.

20. Apparatus according to claim 15 wherein the potential energy comprises electromagnetic potential energy.

21. Apparatus according to claim 20 wherein the element that stores electromagnetic potential energy is a capacitor.

22. Apparatus according to claim 15 wherein the coupling apparatus comprises a shape memory alloy that changes between austenite and martensite phases to control coupling of the piezoelectric motor to the moveable body.

23. Apparatus according to claim 15 wherein the coupling apparatus comprises a circuit configured to excite vibrations of the piezoelectric motor substantially only in a direction parallel to a normal to a surface region of the moveable body to which the motor is pressed to decouple the motor from the moveable body.

24. Apparatus according to claim 15 wherein the apparatus comprises a lock wherein in one of the first and second positions of the moveable body the lock is locked and in the other the lock is unlocked.