Buckling mode actuation of fiber scanner to increase field of view

• US 10,422,991 B2
• Filed: 04/03/2018
• Issued: 09/24/2019
• Est. Priority Date: 04/04/2017
• Status: Active Grant

• Current Assignee: Magic Leap, Inc.
• Original Assignee: Magic Leap, Inc.
• Inventors: Dalrymple, Timothy Mark, Duenner, Andrew C., Carlomagno, Albert Daniel, Zhang, Xiaoyang, Johnson, Michael Robert, Jones, Jr., William K., Melville, Charles David
• Primary Examiner(s): Wong, Tina M
• Application Number:
  US15/944,390
• Publication Number:
  US 20180284425A1
• Time in Patent Office: 539 Days
• Field of Search: None
• CPC Class Codes: G02B 26/103 having movable or deformable optical fibres, light guides or waveguides as scanning elements light guides per se G02B6/00
• CPC Class Codes: H02N 2/0075 Electrical details, e.g. drive or control circuits or methods
• CPC Class Codes: H04N 9/14 using optical-mechanical scanning means only
• CPC Class Codes: H04N 9/3179 Video signal processing therefor
• CPC Class Codes: H10N 30/2027 having cylindrical or annular shape
• CPC Class Codes: H10N 30/802 Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits
• CPC Class Codes: H10N 30/87 Electrodes or interconnections, e.g. leads or terminals

Abstract

Described herein are embodiments of fiber scanning systems and methods of scanning optical fibers. The disclosed systems and methods advantageously provide an improvement to the scanning range, the oscillation amplitude, and/or the maximum pointing angle for an optical fiber in a fiber scanning system by inducing a buckling of a portion of the optical fiber.

Claims

1. A system comprising:

an optical fiber having a distal fiber end and a proximal fiber end;

a first electromechanical transducer mechanically coupled to the optical fiber between the distal fiber end and the proximal fiber end, wherein the first electromechanical transducer is configured to apply a buckling force to the optical fiber by reducing a length of the first electromechanical transducer between a distal buckling end of the first electromechanical transducer and a proximal buckling end of the first electromechanical transducer; and

a second electromechanical transducer mechanically coupled to the optical fiber between the distal fiber end and the proximal fiber end, wherein the second electromechanical transducer is configured to excite whirling of the distal fiber end.

2. The system of claim 1, wherein the distal fiber end is unconstrained.

3. The system of claim 1, wherein the buckling force periodically ramps in amplitude, wherein a whirling amplitude for whirling of the optical fiber periodically ramps, and wherein ramping of the buckling force and ramping of the whirling amplitude are synchronized.

4. The system of claim 1, wherein a first joint mechanically coupling the first electromechanical transducer and the optical fiber has a first axial stiffness along an axis parallel to a longitudinal axis of the optical fiber, wherein a second joint mechanically coupling the second electromechanical transducer and the optical fiber has a second axial stiffness along the axis parallel to the longitudinal axis of the optical fiber, and wherein the first axial stiffness and the second axial stiffness are sufficient to induce buckling of the optical fiber when a distance between the first joint and the second joint is reduced by a distance between 0.1 μ

m and 5 μ

m.

5. The system of claim 1, wherein the first electromechanical transducer corresponds to a buckling piezo having the distal buckling end and the proximal buckling end, and wherein the optical fiber is mechanically coupled to the distal buckling end, the proximal buckling end, or both the distal buckling end and the proximal buckling end.

6. The system of claim 5, wherein the buckling piezo is a piezo tube or piezo stack and wherein the optical fiber passes through the piezo tube or the piezo stack.

7. The system of claim 5, wherein the buckling piezo includes a plurality of electrodes for controlling a length of the buckling piezo by application of one or more voltages.

8. The system of claim 5, wherein the buckling force is applied to the optical fiber by reducing a length of the buckling piezo between the distal buckling end and the proximal buckling end.

9. The system of claim 1, wherein the second electromechanical transducer corresponds to a whirling piezo tube having a distal tube end and a proximal tube end, wherein the optical fiber passes through the whirling piezo tube, and wherein the distal tube end is mechanically coupled to the optical fiber by a whirling distal joint.

10. The system of claim 9, wherein the optical fiber is mechanically coupled to the distal tube end, the proximal tube end, or both the distal tube end and the proximal tube end.

11. The system of claim 9, wherein the whirling piezo tube includes a plurality of electrodes for controlling lateral deflections of the distal tube end by application of one or more voltages.

12. The system of claim 9, further comprising a support tube mechanically coupled to the whirling piezo tube and the first electromechanical transducer, wherein the first electromechanical transducer is positioned inside the support tube.

13. The system of claim 9, wherein the distal fiber end extends beyond the distal tube end, and wherein the distal tube end is positioned between the distal fiber end and the proximal tube end.

14. The system of claim 9, wherein the proximal fiber end extends beyond the proximal tube end, wherein the proximal tube end is positioned between the proximal fiber end and the distal tube end, and wherein the optical fiber is not fixed to the proximal tube end.

15. The system of claim 9, wherein the whirling piezo tube has an inner diameter sufficient to accommodate buckling of the optical fiber.

16. The system of claim 9, wherein the whirling distal joint has an axial stiffness along a longitudinal axis of the whirling piezo tube, wherein the axial stiffness is sufficient to induce buckling of the optical fiber, and wherein the whirling distal joint has a lateral stiffness that is sufficient to accommodate lateral rotation of the optical fiber during buckling.

17. The system of claim 9, wherein the first electromechanical transducer corresponds to a buckling piezo having the distal buckling end and the proximal buckling end, wherein the distal buckling end is positioned between the proximal tube end and the proximal buckling end, wherein the optical fiber and the distal buckling end are mechanically coupled by a buckling distal joint, and wherein movement of the buckling distal joint along a longitudinal fiber axis causes buckling of the optical fiber between the buckling distal joint and the whirling distal joint.

18. The system of claim 17, further comprising a support tube mechanically coupled to the whirling piezo tube and the buckling piezo, wherein the buckling piezo is positioned inside the support tube, wherein the support tube has a distal end and a proximal end, wherein the distal end of the support tube and the proximal tube end are mechanically coupled by a whirling proximal joint, and wherein the proximal end of the support tube and the proximal buckling end are mechanically coupled by a buckling proximal joint.

19. The system of claim 1, wherein the second electromechanical transducer includes a hub, a frame surrounding the hub, and a plurality of lateral electromechanical transducers mechanically coupled to the frame and to the hub, wherein the optical fiber passes through the hub, and wherein the hub is mechanically coupled to the optical fiber by a whirling joint.

20. The system of claim 19, wherein the second electromechanical transducer further includes a plurality of flexures extending radially from the hub and coupling the hub to the frame.

21. The system of claim 19, wherein the lateral electromechanical transducers correspond to piezo elements including electrodes for controlling lateral deflections of the hub to excite whirling of the distal fiber end.

22. The system of claim 1, wherein the first electromechanical transducer and the second electromechanical transducer comprise a piezo tube, wherein the piezo tube has a distal tube end and a proximal tube end, wherein the optical fiber passes through the piezo tube, and wherein the distal fiber end extends beyond the distal tube end, wherein the distal tube end and the optical fiber are mechanically coupled at a distal joint, wherein the proximal tube end and the optical fiber are mechanically coupled at a proximal joint, wherein the distal joint and the proximal joint have axial stiffnesses along a longitudinal axis of the piezo tube that are sufficient to induce buckling of the optical fiber, wherein the distal joint has a lateral stiffness that is sufficient to accommodate lateral rotation of the optical fiber during buckling, and wherein the piezo tube has an inner diameter sufficient to accommodate buckling of the optical fiber between the distal joint and the proximal joint.

23. The system of claim 22, wherein the distal tube end is positioned between the distal fiber end and the proximal tube end, wherein the proximal fiber end extends beyond the proximal tube end, and wherein the proximal tube end is positioned between the proximal fiber end and the distal tube end.

24. The system of claim 22, wherein the piezo tube includes a plurality of electrodes for controlling lateral deflections of the distal tube end and for controlling a length of the piezo tube by application of one or more voltages.

25. The system of claim 24, wherein a buckling voltage simultaneously applied to the plurality of electrodes causes a length of the piezo tube along a longitudinal tube axis to change, and wherein different whirling voltages applied individually to the plurality of electrodes causes the distal tube end to deflect laterally in a spiral configuration.

26. A method comprising:

applying a first voltage to an optical fiber scanning system to induce whirling of an optical fiber, wherein the optical fiber scanning system includes;

the optical fiber, wherein the optical fiber has a distal fiber end and a proximal fiber end;

a first electromechanical transducer mechanically coupled to the optical fiber between the distal fiber end and the proximal fiber end, wherein the first electromechanical transducer is configured to apply a buckling force to the optical fiber by reducing a length of the first electromechanical transducer between a distal buckling end of the first electromechanical transducer and a proximal buckling end of the first electromechanical transducer; and

a second electromechanical transducer mechanically coupled to the optical fiber between the distal fiber end and the proximal fiber end, wherein the second electromechanical transducer is configured to excite whirling of the distal fiber end; and

applying a second voltage to the optical fiber scanning system to induce buckling of the optical fiber.

27. The method of claim 26, wherein the first electromechanical transducer includes a plurality of electrodes, and wherein applying the second voltage includes applying the second voltage to the plurality of electrodes to induce longitudinal application of the buckling force.

28. The method of claim 26, wherein the second electromechanical transducer includes a plurality of electrodes, and wherein applying the first voltage includes applying the first voltage to the plurality of electrodes to induce lateral deflection of the optical fiber for exciting whirling of the distal fiber end.

29. The method of claim 26, wherein whirling of the optical fiber causes the distal fiber end to deflect a first predetermined amount and wherein buckling of the optical fiber causes deflection of the distal fiber end by a second predetermined amount that is superimposed on the first predetermined amount.