Magnetically actuated micromirror and measurement system for motioncharacteristics using specular reflection

摘要

Micromachined magnetically actuated torsional micromirrors havenbeen fabricated. The micromirrors based on silicon were actuated bynmoving magnet system using hard magnetic (Co-Pt) or soft magneticn(Fe-Ni) thin films. And a system to measure motion characteristics ofnthe micromirrors was assembled with an optical table, optical mounts,nand optics. The system is based on a specular reflection of He-Ne lasernfrom the micromirrors. We measured static and resonance characteristicsnof the micromirrors with Co-Pt film or Fe-Ni film. Then we measured Qnfactors of the micromirrors; with Co-Pt film in vacuum. Using our systemnfor measurements, we obtained motion characteristics of micromirrors atnlarge angular deflections. Measured resonance characteristics of allnmicromirrors are in good agreement with the equation of forced vibrationnwith viscous damping. Micromirrors with Co-Pt films have betternreproducibility of torsional motions than ones with Fe-Ni films in bothndc magnetic field and ac magnetic field. And micromirrors with Fe-Ninfilms have torsional motion with subpeak at resonance characteristics.nThe Co-Pt film is more useful as a magnetic film for the micromirrornthan the Fe-Ni film at static and resonance characteristics