Method of operating a fast scanning mirror

• US 8,752,969 B1
• Filed: 10/14/2008
• Issued: 06/17/2014
• Est. Priority Date: 10/15/2007
• Status: Active Grant

• Current Assignee: Arete Associates
• Original Assignee: Arete Associates
• Inventors: Kane, David M., Hillman, Kelly, Hornberg, Christopher, Hunt, John, Paul, Andrew E.
• Primary Examiner(s): Chwasz, Jade R
• Application Number:
  US12/287,881
• Time in Patent Office: 2,072 Days
• Field of Search: 359/876, 356/139.05
• US Class Current: 359/872
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: G01C 11/025 by scanning the object
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G02B 26/105 with one or more pivoting mirrors or galvano-mirrors G02B26/101 takes precedence
• CPC Class Codes: G02B 7/1821 for rotating or oscillating mirrors

Abstract

The mirror has a base, inner stage, reflector, controller, and mechanical subsystems pivotally supporting stage and reflector: subsystem #1, the stage (about one rotation axis, relative to the base); subsystem #2, the reflector (about another axis, relative to the stage). Stage and reflector each rotate on respective jewel, ceramic or other refractory bearings. Controller establishes stage/base and reflector/stage angles. Subsystems include respective bearings. The method includes (1) using the two-axis mechanism to receive, and measure an incident angle of, incident rays from an external object; (2) then using that mechanism to direct a radiation beam from a laser source toward the external object, responsive to incident rays. Optionally step (1) operates the mirror at peak acceleration, or minimum response time, as function of mirror thickness; and provides two- to three-millimeter mirror thickness. Optionally step (2) directs the beam to disrupt object function or impair object structure.

Claims

1. A method of operating an adjustable mirror to detect and respond to an incident ray from an external object, and to redirect a radiation beam from a laser source;

wherein said adjustable mirror has an associated dual-axis steering device comprising;

an inner stage,

first mechanical means for pivotally supporting the inner stage about a first rotational axle on a first axis of rotation, said inner stage being rotatable relative to a base on a first frictionally rotational pivot point without developing torsional deformation of the first rotatable axle,

a reflector,

second mechanical means for pivotally supporting the reflector from the inner stage, about a second rotational axle on a second axis of rotation, said reflector being rotatable relative to said inner stage on a second frictionally rotational pivot point without developing torsional deformation of the second rotatable axle, and

a magnetic-circuit control system for controlling an angle of the reflector with respect to a radiation beam from the laser source, and

said method comprising the steps of;

first, utilizing the dual-axis steering device to measure an incident angle of the incident ray from the external object; and

second, utilizing the magnetic-circuit control system of the dual-axis steering device to steer the reflector to direct the radiation beam from the laser source toward the external object in response to the measured incident ray.

2. The method of claim 1, wherein the second utilizing step comprises:

directing such a radiation beam to disrupt functioning or impair structural integrity of the external object; and

the directing step comprises pivoting at least one of the inner stage, relative to the base, or the reflector relative to the inner stage, by flow of magnetic flux in said circuit.

3. The method of claim 1, wherein the mirror is a magnet, the first utilizing step comprises:

operating the mirror at a peak of acceleration as a function of mirror thickness.

4. The method of claim 1, wherein the first utilizing step comprises:

preparing the mirror in the form of an ellipse, with thickness of roughly two to three millimeters.

5. The method of claim 1, wherein the mirror, and plural radial magnetic cores adjacent to the mirror, are parts of the magnetic circuit;

said first utilizing step comprises;

operating the mirror at a minimum of response time as a function of mirror thickness.

6. The method of claim 1, wherein the first rotational axle is adapted to rotate around the first frictionally rotational pivot point on a first non-resilient rotatable bearing and wherein the second rotational axle is adapted to rotate around the second frictionally rotational pivot point on a second non-resilient rotatable bearing;

wherein the first and the second non-resilient rotatable bearings each have zero rotational restoring force.

7. The method of claim 1, further comprising the step of:

maintaining an angle of the reflector by maintaining a rotational balance point about the first frictionally rotational pivot point and the second frictionally rotational pivot point without torsional forces from either the first frictionally rotational pivot point or the second frictionally rotational pivot point.

8. The method of claim 1, wherein the magnetic-circuit control system further comprises:

means for monitoring the reflector position to develop positional or rotational feedback signals used in rotating the reflector.

9. The method of claim 8, wherein the monitoring means comprise:

an auxiliary optical system that directs an auxiliary radiation beam to the back of the reflector and responds to the auxiliary beam after return from the back of the reflector, to determine rotational angle, or angular velocity or acceleration, of the reflector.

10. The method of claim 9, wherein the auxiliary optical system comprises:

a position-sensing detector (PSD) that determines displacement of the returned beam at the back of the reflector.

11. The method of claim 9, wherein the auxiliary optical system comprises:

an interferometer that counts fringes to determine position of the reflector directly.

12. The method of claim 1, wherein the magnetic-circuit control system comprises:

a digital driving signal generator.

13. The method of claim 1, wherein the magnetic-circuit control system comprises:

a pulse width modulation driving signal generator.

14. The method of claim 1, wherein at least one of the first and second frictionally rotational pivot points comprises:

a rotational bearing made of jewel, ceramic or refractory material.

15. A method of operating an adjustable mirror, which is a magnet forming part of a magnetic circuit, to detect and respond to an incident ray from an external object, and to redirect a radiation beam from a laser source;

wherein said adjustable mirror has an associated dual-axis steering device comprising;

an intermediary inner stage,

first mechanical means for pivotally supporting the intermediary inner stage to rotate about a first rotational axle on a first axis of rotation, said intermediary inner stage being rotatable relative to a base on one or more first frictionally rotational pivot points without developing torsional deformation of the first rotatable axle,

a reflector,

second mechanical means for pivotally supporting the reflector from the intermediary inner stage to rotate about a second rotational axle on a second axis of rotation, said reflector being rotatable relative to said intermediary inner stage on one or more second frictionally rotational pivot points without developing torsional deformation of the second rotatable axle, and

a control system establishing angles of the inner stage and of the reflector, and

said method comprising the steps of;

first, utilizing the dual-axis steering device to measure an incident angle of the incident ray from the external object; and

second, utilizing the control system of the dual-axis steering device to steer the reflector to direct the radiation beam from the laser source toward the external object in response to the measured incident ray.

16. The method of claim 15, wherein the first rotational axle is adapted to rotate around the one or more first frictionally rotational pivot points on one or more first non-resilient rotatable bearings and wherein the second rotational axle is adapted to rotate around the one or more second frictionally rotational pivot points on one or more second non-resilient rotatable bearings;

wherein the one or more first and the one or more second non-resilient rotatable bearings each have zero rotational restoring force.

17. The method of claim 15, further comprising the step of:

maintaining an angle of the reflector by maintaining a rotational balance point about the one or more first frictionally rotational pivot points and the one or more second frictionally rotational pivot points without torsional forces from either the one or more first frictionally rotational pivot points or the one or more second frictionally rotational pivot points.

18. The method of claim 17, wherein the maintaining is performed by controlling with the control system an incremental difference in magnetic forces causing at least one twisting moment about one of the one or more first frictionally rotational pivot points or about one of the one or more second frictionally rotational pivot points.

19. The method of claim 17, wherein the maintaining is performed by controlling with the magnetic-circuit control system an incremental difference in magnetic forces causing at least one twisting moment about one of the first frictionally rotational pivot point and the second frictionally rotational pivot point.

20. The method of claim 15, wherein the one or more first frictionally rotational pivot points and the one or more second frictionally rotational pivot points comprise:

a rotational bearing made of jewel, ceramic or refractory material.