Systems, methods and devices for actuating a moveable miniature platform

Abstract

Presented herein are systems, methods and devices relating to miniature actuatable platform systems. According to one embodiment, the systems, methods, and devices relate to controllably actuated miniature platform assemblies including a miniature mirror.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a support structure having a magnetically assisted pivot interface with a hemispherical platform cavity according to an illustrative embodiment of the invention.

FIG. 2 is a cross-sectional view of a support structure similar to the embodiment of FIG. 1, but having a conical platform cavity according to an alternative illustrative embodiment of the invention.

FIG. 3 is a cross-sectional view of a support structure similar to the embodiment of FIG. 1, but having a V-shaped platform cavity according to another illustrative embodiment of the invention.

FIG. 4 is a system including the support structure of FIG. 2 along with a magnetic platform actuator according to an illustrative embodiment of the invention.

FIG. 5 is a cross-sectional view of a gimbaled assembly for multi axis positioning of a platform and having a stationary central support structure according to another illustrative embodiment of the invention.

FIG. 6A is a top perspective view of an exemplary gimbal platform assembly for use with the assembly of FIG. 5 illustratively rotated about a y-axis.

FIG. 6B is a top perspective view of the gimbal platform assembly of FIG. 6A illustratively rotated about an x-axis.

FIG. 7A is a top view of a gimbal platform assembly of the type depicted in FIGS. 5-6B and employing integrally formed rotational flexures according to an illustrative embodiment of the invention.

FIG. 7B is a magnified view of partially fabricated, folded rotational flexures similar to those of FIG. 7A.

FIGS. 8A-8B are a cross-sectional conceptual diagram of a system including a gimbaled platform assembly of the type depicted in FIGS. 5-7 and a magnetic platform actuator according to an illustrative embodiment of the invention.

FIGS. 9A-9E depict gimbaled platform assemblies for multi-axis positioning of a platform having a stationary outer frame according to various additional illustrative embodiments of the invention.

FIG. 9F is a graph depicting illustrative raster scan angles for a fast resonant axis and the slow non-resonant axis of tilt over time, according to an illustrative embodiment of the invention.

FIG. 10 is a support system including the gimbaled platform assembly of FIG. 9B along with magnetic platform actuators according to one illustrative embodiment of the invention.

FIG. 11 is a support system of the type depicted in FIG. 10 but employing magnetic platform actuators according to an alternative illustrative embodiment of the invention.

FIG. 12 is a conceptual diagram of an arrangement for platform position sensing according to an illustrative embodiment of the invention.

FIG. 13 is a block diagram showing a control system for controlling platform position and employing a platform sensing arrangement of the type depicted in FIG. 12.

Claims

1. A miniature actuatable platform system comprising, a support assembly including a support element having first and second ends, the first end including permanent magnet, anda platform assembly including a platform having first and second opposed sides, the first side in contact with and magnetically coupled to the first end of the support element such that the platform is free to tilt at least between first and second planes, the second side including a reflector.

2. The system of claim 1 including a magnetic bearing positionally fixed to the first end of the support element for including the permanent magnet.

3. The system of claim 1, wherein the support element includes a receptacle at the first end for receiving a magnetic bearing for including the permanent magnet.

4. The system of claim 3, wherein the magnetic bearing is positionally fixed within the receptacle.

5. The system of claim 3, wherein the magnetic bearing is rotatably seated within the receptacle.

6. The system of claim 1, wherein the platform assembly includes at least a portion that is a permanent magnet.

7. The system of claim 6, wherein the permanent magnet of the platform assembly interacts with the permanent magnet of the support element to create a spring restoring force.

8. The system of claim 7, wherein the spring restoring force acts to center the platform on the support element.

9. The system of claim 1, comprising at least one magnet attached to the platform assembly.

10. The system of claim 1, wherein the platform assembly includes a cavity formed into the first side, the first end of the support element contacting the first surface of the platform of the platform assembly within the cavity.

11. The system of claim 10, wherein the cavity is hemispherical.

12. The system of claim 10, wherein the cavity is conical.

13. The system of claim 10, wherein the cavity is v-shaped and extends along at least a portion of a diameter of the platform assembly.

14. The system of claim 3, wherein the magnetic bearing has a surface, and the surface has a low coefficient of friction coating.

15. The system of claim 14, wherein the coating is one of Cr, Al2O3, Si3N4, and diamond-like carbon.

16. The system of claim 10, wherein the cavity has a surface, and the surface has a low coefficient of friction coating.

17. The system of claim 16, wherein the coating is one of Cr, Al2O3, Si3N4, and diamond-like carbon.

18. The system of claim 10, wherein the cavity has a surface formed from a ferromagnetic material.

19. The system of claim 1 comprising an actuator for providing a magnetic field for controllably tilting the platform.

20. The system of claim 19 wherein the actuator includes an actuation coil for generating the magnetic field in response to an applied current drive through the coil.

21. The system of claim 1 comprising at least one magnetic sensor for sensing an angle of tilt of the platform relative to at least one axis.

22. A miniature actuatable platform assembly comprising, a gimbal having first, second and third toroidal gimbal plates, the first gimbal plate being a radially innermost plate, the third gimbal plate being a radially outer most gimbal plate, and the second gimbal plate being located radially intermediate to the first and third plates,a first pair of rotational flexures extending between the first and second gimbal plates along a first axis,a second pair of rotational flexures extending between the second and third gimbal plates along a second axis,a support assembly for mechanically coupling with the first gimbal plate for supporting the gimbal,a magnet mounted on the gimbal, anda platform mounted on the magnet.

23. The system of claim 22, wherein the first, second and third gimbal plates, and the first and second flexure pairs are formed monolithically.

24. The system of claim 22, wherein the magnet extends around at least a portion of a periphery of the gimbal.

25. The system of claim 22 comprising a reflector on a surface of the platform.

26. The system of claim 22 comprising at least one coil for generating a magnetic field in response to a drive current for attracting the magnet to tilt the platform from at least a first plane to at least a second plane.

27. A miniature actuatable platform assembly comprising, a frame,a platform,a pair of rotational flexures for rotatably suspending the platform within the frame, the rotational flexures located along a first axis,a support structure for rotatably supporting the frame and having an axis of rotation substantially orthogonal to the first axis,at least a first magnetic coil for controlling rotational position of the platform relative to the frame, andat least a second magnetic coil for controlling rotational position of the frame relative to the support structure.

28. The system of claim 27 comprising a pair of spindles for rotatably coupling the support structure and the frame, the spindles being located along a second axis substantially orthogonal to the first axis.

29. The system of claim 27 comprising a mirror on a first surface of the platform.

30. The system of claim 29 comprising a magnet on a second surface of the platform.

31. The system of claim 27 comprising a platform position sensor for sensing an angle of rotation of the platform.

32. The system of claim 31 comprising a frame position sensor for sensing an angle of rotation of the frame.

33. A method of generating a raster scan comprising: tilting a mirror on a platform rotationally suspended in a frame by a pair of flexures about a first axis to a first position about the first;resonating the frame rotationally about a second axis at a resonant frequency of the rotational flexures, andtilting the mirror about the first axis to a second position about the first axis.

34. The method of claim 33 comprising providing feedback on the tilt of the platform and the frame by a magnetic sensor.

35. The method of claim 34, wherein the first axis has zero-spring restoring force.