Imaging of acoustic pressure radiation from vibrating microstructure in atmosphere using thermal microprobe

摘要

This letter reports on an imaging technique of acoustic pressure radiation (APR) from vibrating micro-anostructures and their mechanical defects. Resonance oscillation of micro-anometer beams in use of viscous environments is important for various sensing applications. Viscous dumping is the main energy loss mechanism, which determines the quality factor of resonance in viscous fluid. The APR due to viscous dumping is imaged using a scanning thermal flow sensor. A platinum heater or micromachined silicon heater is heated up by flowing a current, and the acoustic particle velocity which originated from APR is detected. Imaging of APR is demonstrated and compared with the actual vibration image. Also, strong APR is observed from a crack on the support of a silicon beam.