US 12,265,158 B2
Magnetic sensing for a polygon mirror using a hall sensor for LiDAR system
Youmin Wang, Berkeley, CA (US); and Yufeng 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 Apr. 22, 2021, as Appl. No. 17/238,071.
Prior Publication US 2022/0342076 A1, Oct. 27, 2022
Int. Cl. G01S 17/931 (2020.01); G01D 5/14 (2006.01); G01S 7/481 (2006.01); G01S 7/484 (2006.01); G02B 26/12 (2006.01); H02K 11/215 (2016.01)
CPC G01S 17/931 (2020.01) [G01S 7/4817 (2013.01); G01S 7/484 (2013.01); G02B 26/121 (2013.01); H02K 11/215 (2016.01); G01D 5/145 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A magnetic sensing system for a polygon mirror,
comprising:
a disc permanent magnet configured to provide a magnetic field;
a Hall sensor configured to generate a voltage proportional to the strength of the magnetic field as the Hall sensor and the disc permanent magnet move relatively to each other when the polygon mirror rotates, wherein one of the disc permanent magnet and the Hall sensor locates on and rotates with the polygon mirror and the other locates off the polygon mirror, wherein the Hall sensor and the disc permanent magnet are placed such that a distance between the Hall sensor and the center of the disc permanent magnet changes, as they move relatively to each other; and
at least one controller configured to determine a rotation angle of the polygon mirror based on the generated voltage by the Hall Sensor.