MEMS mirror device having a stabilization ring and reduced static reflection
Methods and systems for using a MEMS mirror for steering a LiDAR beam and for minimizing statically emitted light from a LiDAR system are disclosed. A LiDAR system includes a light source that emits a light beam directed at a MEMS device. The MEMS device includes a manipulable mirror that reflects the emitted light beam in a scanning pattern. The MEMS device also includes a stabilization ring positioned adjacent to and at least partially surrounding the mirror. An attenuation layer is disposed on a top surface of the stabilization ring and is configured to attenuate light reflected by the stabilization ring.
1. A LiDAR system comprising:
a light source that emits a light beam directed at a MEMS device, wherein the MEMS device includes:
a manipulable mirror that reflects the emitted light beam through an aperture of the LiDAR system and steers the reflected light beam in a scanning pattern outside of the LiDAR system;
a stabilization ring that forms an annular ring around the mirror and is attached to the mirror with one or more tie bars;
a substrate positioned adjacent to and at least partially surrounding the stabilization ring;
an attenuation layer disposed directly on a top surface of the stabilization ring, wherein the attenuation layer attenuates light reflected by the stabilization ring that passes through the aperture; and
a receiver that receives light reflected off an object outside of the LiDAR system.
2. The LiDAR system of claim 1 wherein when the mirror is manipulated the mirror move in-phase with the stabilization ring.
3. The LiDAR system of claim 1 wherein when the mirror is manipulated the mirror moves out of phase with the stabilization ring.
4. The LiDAR system of claim 1 wherein the one or more tie bars includes four tie bars that are uniformly distributed around the mirror.
5. The LiDAR system of claim 1 wherein the one or more tie bars includes two tie bars positioned on opposite sides of the mirror.
6. The LiDAR system of claim 1 wherein the light beam includes a center portion that is reflected by the manipulable mirror and a tail portion that surrounds the center portion and is reflected by the stabilization ring.
7. The LiDAR system of claim 1 wherein the attenuation layer comprises an anti-reflective coating.
8. The LiDAR system of claim 1 wherein the mirror and the stabilization ring each have oval geometry.
9. The LiDAR system of claim 1 wherein the attenuation layer comprises a diffraction grating.
10. The LiDAR system of claim 1 wherein the attenuation layer comprises a diffuse reflection coating.
11. The LiDAR system of claim 1 wherein the attenuation layer comprises an absorbing coating.
12. A micro-electromechanical system (MEMS) package comprising:
a manipulable mirror having a reflective surface;
a stabilization ring that forms an annular ring around the mirror and is attached to the mirror with one or more tie bars;
a substrate positioned adjacent to and at least partially surrounding the stabilization ring; and
an attenuation layer disposed directly on a top surface of the stabilization ring, wherein the attenuation layer attenuates light reflected by the stabilization ring.
13. The MEMS package of claim 12 configured to receive a light beam including a center portion and a tail portion that surrounds the center portion;
wherein the center portion of the light beam is reflected by the mirror; and
wherein the attenuation layer attenuates an intensity of the tail portion that is reflected by the stabilization ring.
14. The MEMS package of claim 12 wherein when the mirror is manipulated the mirror moves in-phase with the stabilization ring.
15. The MEMS package of claim 12 wherein when the mirror is manipulated the mirror moves out of phase with the stabilization ring.
16. The MEMS package of claim 12 wherein the one or more tie bars includes four tie bars that are uniformly distributed around the mirror.
17. The MEMS package of claim 12 wherein the one or more tie bars includes two tie bars positioned on opposite sides of the mirror.
18. A method of using a micro-electromechanical system (MEMS) package comprising:
receiving a light beam through a window of the MEMS package, wherein the light beam has a center portion and a tail portion that surrounds the center portion;
steering a reflection of the center portion of the light beam by reflecting the center portion of the light beam off a mirror, wherein the mirror is moved by a stabilization ring that forms an annular ring around the mirror and is attached to the mirror with one or more tie bars; and
attenuating a reflection of the tail portion of the light beam that is reflected off the stabilization ring using an attenuation layer disposed directly on a top surface of the stabilization ring.
19. The method of claim 18 wherein when the mirror is manipulated the mirror moves in-phase with the stabilization ring.
20. The method of claim 18 wherein when the mirror is manipulated the mirror moves out of phase with the stabilization ring.