A Two-Degree-of-Freedom Micro Electromagnetic Actuator Utilizing a Fine Pitch and Multi-Pole Magnetized Permanent Magnet

Abstract

Aiming the use in an optical image stabilizer for smart phone cameras, a two-degree-of-freedom micro actuator consisting of a thin permanent magnet having a fine pitch chessboard magnetic pattern, a two-layer printed-coil and a silicon elastic guideway was proposed and fabricated. The permanent magnet of 9.1 x 9.1 x t 0.5 mm was processed by wire electric discharge machining to minimize the damage of the magnetic properties. The permanent magnet with lattice-patterned grooves for thermal insulation was multi-pole-magnetized by laser assisted heating. The elastic guideway was machined using deep reactive ion etching. The driving forces of 1.24 and 1.66 mN and the positioning ranges of 211 and 282 μm in the X and Y directions, respectively, were obtained with a coil current of ±0.1 A in each layer coil.