MEMS device with multi-segment flexures
A microelectromechanical systems (MEMS) device includes a scanning platform suspended from a fixed platform by two flexures that form a pivot axis. The two flexures may be symmetric or asymmetric about a centerline of the scanning platform. At least one flexure includes two segments that are not parallel to each other. A second flexure may include two segments with one segment being wider than the other. Flexure design reduces effects of mounting and thermal stresses when the MEMS device is mounted as part of an assembly.
1. A scanning mirror assembly comprising:
a microelectromechanical system (MEMS) device that includes a fixed platform and a scanning platform suspended from the fixed platform by first and second flexures, wherein the first flexure is coupled with the fixed platform via a first flexure segment, and the second flexure is coupled with the fixed platform via a second flexure segment, the first flexure segment being wider than the second flexure segment; and
a sensor disposed on the first flexure segment to produce an output in response to rotation of the scanning platform about a pivot axis;
wherein the output of the sensor at an undesirable mode of vibration of the scanning platform is reduced due to the sensor being disposed on the wider first flexure segment.
2. The scanning mirror assembly of claim 1 wherein the fixed platform comprises a silicon substrate.
3. The scanning mirror assembly of claim 2 wherein the component comprises metal.
4. The scanning mirror assembly of claim 2 wherein the component comprises plastic.
5. The scanning mirror assembly of claim 2 wherein the component comprises a magnetic material.
6. The scanning mirror assembly of claim 5 further comprising a plastic spacer between the fixed platform and the magnetic material.
7. The scanning mirror assembly of claim 1 wherein the first and second flexures each include the first and second segments, wherein the first segment is coupled to the scanning platform and the second segment is bisected perpendicularly by the first segment, and the second segment has ends that are coupled to the fixed platform.
8. The scanning mirror assembly of claim 7 further comprising bonding sites located beyond, and along an axis defined by, the first and second flexures, wherein the fixed platform is bonded to a component at the bonding sites, the component comprising a material dissimilar to that of the fixed platform.
9. A scanning mirror assembly comprising:
at least one magnet;
a moving-coil microelectromechanical system (MEMS) scanning mirror device mounted to the at least one magnet, the moving-coil MEMS scanning mirror device comprising a fixed platform bonded to the at least one magnet, a scanning platform, and first and second flexures coupling the scanning platform to the fixed platform, wherein the first flexure is coupled with the fixed platform via a first flexure segment, and the second flexure is coupled with the fixed platform via a second flexure segment, the first flexure segment being wider than the second flexure segment; and
a sensor disposed on the first flexure segment to produce an output in response to rotation of the scanning platform about a pivot axis;
wherein the output of the sensor at an undesirable mode of vibration of the scanning platform is reduced due to the sensor being disposed on the wider first flexure segment.
10. The scanning mirror assembly of claim 9 wherein the fixed platform comprises a silicon substrate.
11. The scanning mirror assembly of claim 9 further comprising a plastic spacer between the at least one magnet and at least a portion of the fixed platform.
12. The scanning mirror assembly of claim 9 wherein both the first and second flexures include first and second segments at right angles.
13. The scanning mirror assembly of claim 9 further comprising bonding sites located beyond, and along an axis defined by, the first and second flexures, wherein the fixed platform is bonded to the at least one magnet at the bonding sites.
14. The scanning mirror assembly of claim 9 wherein the first segment is coupled to the scanning platform and the second segment is bisected perpendicularly by the first segment, and the second segment has ends that are coupled to the fixed platform.
15. A mobile device comprising:
a light source to provide a light beam;
a scanning mirror assembly to reflect the light beam, the scanning mirror assembly including at least one magnet and a moving-coil microelectromechanical system (MEMS) scanning mirror device mounted to the at least one magnet, the moving-coil MEMS scanning mirror device comprising a fixed platform bonded to the at least one magnet, a scanning platform, and first and second flexures coupling the scanning platform to the fixed platform, wherein the first flexure is coupled with the fixed platform via a first flexure segment, and the second flexure is coupled with the fixed platform via a second flexure segment, the first flexure segment being wider than the second flexure segment; and
a sensor disposed on the first flexure segment to produce an output in response to rotation of the scanning platform about a pivot axis;
wherein the output of the sensor at an undesirable mode of vibration of the scanning platform is reduced due to the sensor being disposed on the wider first flexure segment.
16. The mobile device of claim 15 wherein the fixed platform comprises a silicon substrate.
17. The mobile device of claim 15 further comprising a plastic spacer between the at least one magnet and at least a portion of the fixed platform.
18. The mobile device of claim 15 wherein both the first and second flexures include first and second segments at right angles.
19. The mobile device of claim 15 further comprising bonding sites located beyond, and along an axis defined by, the first and second flexures, wherein the fixed platform is bonded to the at least one magnet at the bonding sites.
20. The mobile device of claim 15 wherein the first segment is coupled to the scanning platform and the second segment is bisected perpendicularly by the first segment, and the second segment has ends that are coupled to the fixed platform.