Large-displacement electromagnetic actuators using the meander springs partially exposed to magnetic field

Abstract

In this work, we proposed and investigated the large-displacement electromagnetic actuators using the meander springs partially exposed to magnetic field for optical applications. The present actuator is proposed by partial exposure of meander springs to magnetic field for adopting the meander springs with low spring constant in the limited area of structure under the magnetic field generated by the two layers of ring type permanent magnets. Compared to previous electromagnetic actuators, present method enables low spring constant to obtain large-displacement. The prototype F with meander springs which are exposed to magnetic force that can generate Lorentz force along the direction of displacement, and the prototype B with meander springs which are exposed to magnetic force that can generate Lorentz force along and against the direction of displacement were designed and fabricated to experimentally verify the difference of performance. In the experimental study, the prototype was fabricated by the single mask fabrication process using SOI wafer. As experimental results, the prototype F, compare to the prototype B, increased by 18.4 ~ 21.5 % of amplitude in low frequency actuation, and increased by 20.0 ~ 51.9 % of amplitude in resonant frequency actuation, respectively. In this thesis, we experimentally verified the large-displacement actuation capability of the present electromagnetic actuators for the optical applications such as camera phone shutters, optical choppers and optical attenuators.