Oscillation FPCB micromirror based triangulation laser rangefinder
Vixen Joshua Tan, Siyuan He
Abstract
Abstract This paper reports an electromagnetic oscillation flexible printed circuit board (FPCB) micromirror based scanning triangulation laser rangefinder (LRF). The FPCB micromirror has a large aperture (8 mm × 5.5 mm) and high flatness (radius of curvature, ∼ 15 m), that overcomes conventional MEMS micromirrors’ limitation of a small aperture size (less than 5 mm). Subsequently high power lasers with large beam sizes and good collimation can be used in micromirror based scanning LRF for better performance. As a result, the LRF in this paper achieved a larger scanning angle and longer detecting distance than those in literature. Both modelling and prototyping are presented. Three lasers (Laser 1: 2 mW; Laser 2: 20 mW; and Laser 3: 100 mW) are used to characterise the LRF. Eye-safety calculation is presented for the three lasers. Achieved performance (measurement distance and field of view (FOV)) is: with Laser 1, distance of 15–70 cm and FOV of −15° to 10°, error ≤ 4%; with Laser 2, distance of 15–130 cm and FOV of −15° to 15°, error ≤ 5%; with Laser 3, distance 15–200 cm and FOV of −15° to (5 ∼ 9°), error ≤ 5%. Fatigue test indicates 0.8 billion scanning cycles have been reached.