MEMS-based, low wobble scanners developed

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Researchers at the The Fraunhofer IPMS have developed a customised silicon-based resonant and quasi-static micro-electromechanical system (MEMS) for deflection and modulation of light. The device is intended as a replacement for conventional galvanometer-based optical scanners, which typically feature large optical apertures. The design of conventional scanners can limit the precision of motion, particularly at high velocity.

A characteristic measure for the quality of scanner motion is the dynamic mirror tilt, perpendicular to the axis of rotation. Mirror tilt leads to a tumbling motion and a deformation of the scanned beam, often referred to as cross-axes wobble. Cross-axes wobble of conventional resonant galvanometer scanners is typically in the order of 200μrad.

The silicon-based resonant and quasi-static micro-electromechanical system developed by Fraunhofer offers high velocity scanning with superior precision, and the researchers have now demonstrated that typical resonant designs provide a cross-axes wobble of less than 35μrad. Thereby the device oscillates at 23kHz with a mechanical amplitude of ±9°.

Dr André Dreyhaupt, scientist at the microscanner product development group, stated: 'The optical MEMS structures of the Fraunhofer IPMS perfectly fit for challenging applications with high demands on velocity and precision of motion at the same time.'