US 11,747,470 B2
Rotation angle sensing and control of mirror assembly for light steering
Sergio Fabian Almeida Loya, Mountain View, CA (US); and Youmin Wang, Mountain View, CA (US)
Assigned to Beijing Voyager Technology Co., Ltd., Beijing (CN)
Filed by Beijing Voyager Technology Co., Ltd., Beijing (CN)
Filed on Dec. 4, 2020, as Appl. No. 17/112,126.
Prior Publication US 2022/0179070 A1, Jun. 9, 2022
Int. Cl. G01S 17/02 (2020.01); G02B 26/08 (2006.01); G01S 7/481 (2006.01)
CPC G01S 17/02 (2013.01) [G02B 26/0833 (2013.01); G01S 7/4817 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An apparatus comprising a light detection and ranging (LiDAR) module, the LiDAR module including:
a semiconductor integrated circuit, the semiconductor integrated circuit including a microelectromechanical system (MEMS), a substrate on which the MEMS is formed, and a controller, the MEMS including one or more micro-mirror assemblies, each micro-mirror assembly including:
a micro-mirror comprising a first connection structure and a second connection structure, the first connection structure being connected to the substrate at a first pivot point, the second connection structure being connected to the substrate at a second pivot point;
an actuator configured to rotate the micro-mirror to reflect light emitted by a light source out of the LiDAR module or to reflect light received by the LiDAR module to a receiver; and
a measurement circuit electrically connected to at least one of the first connection structure or the second connection structure, the measurement circuit being configured to measure an electrical resistance of at least one of the first connection structure or the second connection structure,
wherein the controller is configured to, for each micro-mirror assembly:
determine a first signal based on a target rotation angle of the micro-mirror;
transmit the first signal to the actuator of the micro-mirror assembly to cause the micro-mirror to rotate to a first angle;
obtain, from the measurement circuit, a measurement of the electrical resistance of at least one of the first connection structure or the second connection structure while the micro-mirror is at the first angle;
determine, based on the measurement of the electrical resistance, an actual rotation angle of the micro-mirror in response to the first signal;
determine a second signal based on a relationship between the target rotation angle and the actual rotation angle; and
transmit the second signal to the actuator of the micro-mirror assembly, wherein the second signal causes the micro-mirror to rotate from the first angle to the target rotation angle.