Electromagnetically Actuated FR4 Scanners

A torsional micromechanical scanner is fabricated from thin fire resistant 4 substrates using standard printed circuit board technology. The top and the bottom copper layers are connected with vias and shaped as a single coil to enable one- and two-dimensional electromagnetic actuation with an external magnet. Using 5 mm times 5 mm mirrors, the following scan angle and resonant frequency combinations are achieved: 17deg at 1.8 kHz and 140deg at 417 Hz. Another 10times improvement in magnetic actuation torque seems feasible. The technology offers a unique advantage by allowing a high degree of integration with microoptics and electronics directly on the mechanical platform and offers a low-cost alternative to silicon microelectromechanical systems devices particularly when large or low-frequency devices are required.