Electromagnetically actuated 2-axis scanning micromirror with large aperture and tilting angle for lidar applications

This paper presents electromagnetically actuated 2-axis scanning micromirror with large aperture and tilting angle for laser pointing applications such as LIDAR systems. The 2-axis micromirror with the plate size of 3 mm in diameter was fabricated using gimbaled single crystal silicon with a coil and assembled with permanent magnet forming radial magnetic field. The micromirror was realized on SiOG (Silicon on Glass) wafer using 4 photolithography masks and the magnet assembly was optimized to maximize the torque. Horizontal resonance frequency of manufactured micromirror was measured 1.421 kHz and vertical resonant frequency was 396 Hz. The vertical scan angle was 16.87°, 26.32° and 22.61° with the cylindrical magnet diameter of 2.6 mm, 4.0 mm and 4.8 mm respectively. Horizontal maximum scan angle was 24.45° using a cylindrical magnet with the diameter of 4.0 mm. Proposed 2-axial electromagnetically actuated large size micromirror is expected to be applicable to LIDAR system because it can handle high power laser and fast 2-dimensional scanning.