MEMS mirror device with 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 substrate positioned adjacent to and at least partially surrounding the mirror. An attenuation layer is disposed on a top surface of the substrate and is configured to attenuate light reflected by the substrate.
1. A LiDAR system comprising:
a light source positioned within the LiDAR system 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 substrate positioned adjacent to and at least partially surrounding the mirror;
an attenuation system comprising a transparent thin film structure with alternating layers having a contrasting refractive index disposed on a top surface of the substrate that attenuates an intensity of a reflection of the emitted light beam from the attenuation system that exits 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 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 attenuation system.
3. The LiDAR system of claim 1 wherein the attenuation system comprises an anti-reflective coating.
4. The LiDAR system of claim 1 wherein the mirror has an oval shape.
5. The LiDAR system of claim 1 wherein the attenuation system comprises a diffraction grating.
6. The LiDAR system of claim 1 wherein the attenuation system comprises a diffuse reflection coating.
7. The LiDAR system of claim 1 wherein the attenuation system comprises an absorbing coating.
8. A micro-electromechanical system (MEMS) package comprising:
a manipulable mirror having a reflective surface;
a substrate positioned adjacent to and at least partially surrounding the mirror; and
an attenuation system comprising a transparent thin film structure with alternating layers having a contrasting refractive index disposed on the substrate and configured to attenuate an intensity of reflected light.
9. The MEMS package of claim 8 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 system attenuates an intensity of the tail portion that is reflected by the attenuation system.
10. The MEMS package of claim 8 wherein the attenuation system comprises an anti-reflective coating.
11. The MEMS package of claim 8 wherein the mirror has an oval shape.
12. The MEMS package of claim 8 wherein the attenuation system comprises a diffraction grating.
13. The MEMS package of claim 8 wherein the attenuation system comprises a diffuse reflection coating.
14. The MEMS package of claim 8 wherein the attenuation system comprises an absorbing coating.
15. 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 positioned adjacent to a substrate; and
attenuating a reflection of the tail portion of the light beam that is reflected off the substrate using an attenuation system comprising a transparent thin film structure with alternating layers having a contrasting refractive index disposed on a top surface of the substrate.
16. The method of claim 15 wherein the attenuation system comprises an anti-reflective coating.
17. The method of claim 15 wherein the mirror has an oval shape.
18. The method of claim 15 wherein the attenuation system comprises a diffraction grating.
19. The method of claim 15 wherein the attenuation system comprises a diffuse reflection coating.
20. The method of claim 15 wherein the attenuation system comprises an absorbing coating.