Optical adjustable mounts with absolute position feedback
Adjustable mounts for optical elements or the like that may include absolute position information feedback. For some embodiments, position data may be generated independent of displacement measurement. Position data feedback may be provided to driver embodiments, such as piezoelectric inertia drivers, by a controller and used to achieve a desired position setting for an adjustable mount.
1. An adjustable mount for an optical element, comprising:
a first mount body;
a second mount body which is configured to secure an optical element thereto and which is movable relative to the first mount body in an adjustable degree of freedom;
a driver configured to controllably impart relative movement in the adjustable degree of freedom between the first mount body and the second mount body;
a flexible substrate including a first portion secured to the first mount body and a second portion secured to the second mount body;
a strain gauge element mechanically secured to the flexible substrate and configured to register strain of the flexible substrate and generate a signal in response to a strain of the flexible substrate; and
a controller in operative communication with the strain gauge element and configured to generate position data from a signal of the strain gauge element.
2. The adjustable mount of claim 1 wherein 2 or more strain gauge elements are mechanically secured to the flexible substrate.
3. The adjustable mount of claim 1 wherein the strain gauge element is disposed on a resistive strain gauge body of a strain gauge, the strain gauge body being mechanically secured to the flexible substrate.
4. The adjustable mount of claim 3 wherein the strain gauge element includes an electrical circuit which is configured to change electrical impedance in response to strain imposed on a conductive element of the strain gauge.
5. The adjustable mount of claim 1 wherein the flexible substrate comprises a thin flexible sheet including two substantially parallel surfaces and an aperture disposed through a middle portion of the sheet.
6. The adjustable mount of claim 5 wherein the flexible substrate comprises a flat square plate with an aperture in the middle producing a perimeter region having four sides and four corners with the first portion disposed at a first corner and the second portion disposed at a second corner, the second corner disposed opposite the aperture from the first corner.
7. The adjustable mount of claim 1 wherein the driver is manually driven.
8. The adjustable mount of claim 1 wherein the driver is motorized.
9. The adjustable mount of claim 8 wherein the driver comprises a piezoelectric driver.
10. An adjustable mount for an optical element, comprising:
a first mount body;
a second mount body which is configured to secure an optical element thereto and which is movable relative to the first mount body in a first adjustable degree of freedom and a second adjustable degree of freedom;
a first driver configured to controllably impart relative movement in the first adjustable degree of freedom between the first mount body and the second mount body;
a second driver configured to controllably impart relative movement in the second adjustable degree of freedom between the first mount body and the second mount body;
a flexible substrate including a thin flexible sheet with a first portion of the flexible substrate secured to the first mount body and a second portion of the flexible substrate secured to the second mount body;
a strain gauge element mechanically secured to the flexible substrate and configured to register strain of the flexible substrate and generate a signal in response to a strain of the flexible substrate; and
a controller in operative communication with the strain gauge element and configured to generate position data from a signal of the strain gauge element.
11. The adjustable mount of claim 10 wherein 2 or more strain gauge elements are mechanically secured to the flexible substrate.
12. The adjustable mount of claim 11 wherein the flexible substrate comprises a flat square plate with an aperture in the middle producing a perimeter region having four sides and four corners with the first portion disposed at a first corner and the second portion disposed at a second corner, the second corner disposed opposite the aperture from the first corner.
13. The adjustable mount of claim 10 wherein the strain gauge element is disposed on a resistive strain gauge body of a strain gauge, the strain gauge body being mechanically secured to the flexible substrate.
14. The adjustable mount of claim 13 wherein the strain gauge element includes an electrical circuit which is configured to change electrical impedance in response to strain imposed on a conductive element of the strain gauge.
15. The adjustable mount of claim 10 wherein the flexible substrate comprises a thin flexible sheet including two substantially parallel surfaces and an aperture disposed through a middle portion of the sheet.
16. The adjustable mount of claim 10 wherein the second mount body pivots relative to the first mount body at a pivot point disposed between the first mount body and second mount body and which has a first drive surface with a substantially constant radius of curvature relative to the pivot point and a second drive surface which has a substantially constant radius of curvature relative to the pivot point.
17. The adjustable mount of claim 16 wherein the pivot point comprises a ball bearing disposed in a detent which is compressed into engagement by a drive surface of the first and second drivers.
18. The adjustable mount of claim 10 wherein the first and second drivers comprise piezoelectric inertia drivers configured to impart relative movement in the adjustable degrees of freedom between the first mount body and the second mount body, the piezoelectric drivers including:
a rigid body portion having a first piezoelectric member mount surface,
a continuous and flexible resilient member having a first end which includes a second piezoelectric member mount surface, a drive surface portion having a drive surface, an axially rigid portion disposed between and secured to the drive surface portion and the first end, an S-shaped resilient portion extending from the drive surface portion, and a second end portion disposed between and secured to the S-shaped resilient portion and the body portion, and
a piezoelectric member disposed between and secured to the first and second mount surfaces.
19. The adjustable mount of claim 18 wherein the rigid body portion of the piezoelectric inertia driver is secured to the first mount body and the drive surface is frictionally engaged with the second mount body.
20. The adjustable mount of claim 18 wherein the rigid body portion of the piezoelectric inertia driver is secured to the second mount body and the drive surface is frictionally engaged with the first mount body.
21. A method of adjusting an adjustable mount for an optical element, comprising:
providing an adjustable mount for an optical element, comprising:
a first mount body,
a second mount body which is configured to secure an optical element thereto and which is movable relative to the first mount body in an adjustable degree of freedom,
a flexible substrate including a first portion secured to the first mount body and a second portion secured to the second mount body,
a strain gauge element mechanically secured to the flexible substrate and configured to register strain of the flexible substrate and generate a signal in response to a strain of the flexible substrate, and
a controller in operative communication with the stain strain gauge element and configured to generate position data from a strain gauge element signal; and
generating data regarding a first absolute position of the second mount body relative to the first mount body from a strain gauge element signal using the controller.
22. The method of claim 21 further comprising storing position data regarding the first absolute position of the second mount body relative to the position of the first mount body in a data storage device.
23. The method of claim 22 further comprising displacing the second mount body relative to the first mount body, and generating data regarding a second position of the second mount body relative to the first mount body.
24. The method of claim 23 wherein the second mount body is displaced relative to the first mount body with a driver configured to controllably impart relative movement in the adjustable degree of freedom between the first mount body and the second mount body.
25. The method of claim 24 wherein the driver comprises a piezoelectric driver and the second mount body is displaced relative to the first mount body by actuation of the piezoelectric driver.
26. The method of claim 23 further comprising generating a signal from a controller to the driver to displace the second mount body from the second position back to the first absolute position.
27. The method of claim 21 wherein the adjustable mount comprises a plurality of resistive strain gauge elements mechanically secured to the flexible substrate and position data corresponding to the first absolute position of the second mount body relative to the first mount body is generated from an impedance profile of the plurality of resistive strain gauge elements.
28. The method of claim 27 wherein the impedance profile of the plurality of resistive strain gauges is generated with at least one Wheatstone bridge circuit.