MEMS package with double-sided mirror
Methods and systems for using a dual sided MEMS mirror for determining a direction of steered light are disclosed. In one example a MEMS package includes a substrate defining an aperture and a dual sided MEMS mirror is positioned over the aperture. A first surface of the MEMS mirror is used to steer a LiDAR beam that is used to perform LiDAR imaging of an area of interest. As the mirror is moved, a second surface of the mirror reflects a sensing beam onto a detector array. Data from the detector array is used to determine an orientation of the mirror which can then be used to determine a direction of the steered LiDAR beam. The MEMS package can form an enclosure for the MEMS mirror that includes a first and a second transparent window attached to two opposing surfaces of the substrate.
1. A micro-electromechanical system (MEMS) package comprising:
a manipulable mirror having a first reflective surface and a second reflective surface, the first reflective surface and the second reflective surface positioned on opposite sides of a monolithic structure;
a first transparent window positioned adjacent to and aligned with the first reflective surface, the first reflective surface configured to receive and reflect a LIDAR light beam;
a second transparent window positioned adjacent to and aligned with the second reflective surface; and
a detector configured to receive a sensing beam reflected off of the second reflective surface and determine an orientation of the manipulable mirror and related direction of the LIDAR light beam based on the sensing beam.
2. The MEMS package of claim 1 wherein the mirror is a portion of a MEMS device.
3. The MEMS package of claim 2 further comprising a substrate extending between and attached to the first and second transparent windows, the substrate further electrically and mechanically coupled to the MEMS device.
4. The MEMS package of claim 3 wherein the substrate includes an aperture aligned with and positioned over the second reflective surface.
5. The MEMS package of claim 3 wherein a hermetic seal is formed between the substrate and the first and second transparent windows.
6. The MEMS package of claim 1 wherein the first transparent window is positioned to allow the LiDAR light beam to pass through and be reflected off the first reflective surface.
7. The MEMS package of claim 1 wherein the second transparent window is positioned to allow the sensing beam to pass through and be reflected off the second reflective surface.
8. The MEMS package of claim 1 wherein the first transparent window is not parallel with the second transparent window.
9. A method of using a micro-electromechanical system (MEMS) package comprising:
receiving a first light beam through a first window of the MEMS package;
steering a reflection of the first light beam through the first window by reflecting the first light beam off a first surface of a mirror;
receiving a second light beam through a second window of the MEMS package;
steering a reflection of the second light beam through the second window by reflecting the second light beam off a second surface of the mirror, wherein the first surface and the second surface of the mirror are opposite sides of a monolithic structure of the mirror, and
determining an orientation of the mirror by detecting the reflection of the second light beam.
10. The method of claim 9 wherein the orientation of the mirror is used to determine a direction of the reflection of the first light beam.
11. The method of claim 9 further comprising a detector array positioned outside of the MEMS package and configured to detect the reflection of the second light beam.
12. The method of claim 9 wherein the mirror pivots about a first axis and a second axis wherein the first axis is orthogonal to the second axis.
13. The method of claim 12 wherein the mirror pivots in response to an application of one or more electrical signals to a MEMS device that includes the mirror.
14. The method of claim 9 wherein the MEMS package includes a substrate defining an aperture and wherein the second surface of the mirror is aligned with and positioned over the aperture.