科研之友
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摘要
In this work, we combine the advantages of hard magnets, polydimethylsiloxane (PDMS) micro-molding and printed circuit board planar coils to propose an electromagnetically actuated bidirectional scanner with potential applications in bio-medical scanning. The proposed bidirectional scanner (4 mm x 4 mm x 250 mu m) is fabricated by micromolding an isotropic Nd-Fe-B micropowder (MQFP-12-5) doped in a PDMS matrix at 80% weight percentage and magnetized using a standard dipole electromagnet. A reflective gold layer of 100 nm is evaporated onto the polymer composite structure. A maximum magnetic field of 20 mT is measured for the polymer magnetic mirror. Rectangular planar coils (trace width and spacing: 254 mu m; 10 turns) are employed to actuate the bidirectional scanner electromagnetically by Lorentz force. Actuation in both static and dynamic excitation modes is tested. Power consumption at a maximum rotational angle (15 degrees optical) is one watt at 40 Hz resonant frequency. Initial surface roughness of the mirror (165 nm) and radius of curvature (75 mm) has been addressed by depositing a thin layer of PDMS, resulting in 66.24 nm surface roughness and 321.37 mm overall radius of curvature after integration. Major advantages of the proposed bidirectional scanner include low fabrication cost, low input voltage and large actuator displacement compared to existing electrostatic scanners.
- 出版日期2014
