A Two-Dimensional Laser Scanning Mirror Using Motion-Decoupling Electromagnetic Actuators

This work proposes a two-dimensional (2-D) laser scanning mirror with a novel actuating structure composed of one magnet and two coils. The mirror-actuating device generates decoupled scanning motions about two orthogonal axes by combining two electromagnetic actuators of the conventional moving-coil and the moving-magnet types. We implement a finite element analysis to calculate magnetic flux in the electromagnetic system and experiments using a prototype with the overall size of 22 mm (W) x 20 mm (D) x 15 mm (H) for the mirror size of 8 mm x 8 mm. The upper moving-coil type actuator to rotate only the mirror part has the optical reflection angle of 15.7 degrees at 10 Hz, 90 degrees at the resonance frequency of 60 Hz at +/- 3 V (+/- 70 mA) and the bandwidth of 91 Hz. The lower moving-magnet type actuator has the optical reflection angle of 16.20 degrees at 10 Hz and 50 degrees at the resonance frequency of 60 Hz at +/- 5 V (+/- 34 mA) and the bandwidth of 88 Hz. The proposed compact and simple 2-D scanning mirror has advantages of large 2-D angular deflections, wide frequency bandwidth and low manufacturing cost.