Conventional galvanometer-based optical scanners typically feature large optical apertures. However, the macroscopic design limits the precision of motion, particularly at high velocity. Requirements for bearings on moving parts are exceptionally high. A characteristic measure for the quality of motion is the dynamic mirror tilt perpendicular to the axis of rotation. Mirror tilt leads to a tumbling motion and a deformation of the projected figure (see drawing). This property is often referred to as cross-axes wobble. Cross-axes wobble of conventional resonant galvanometer scanners is typically in the order of 200 µrad.
The Fraunhofer IPMS develops customized silicon based resonant and quasi-static micro-electro-mechanical systems (MEMS) for deflection and modulation of light. Those devices offer highest velocity with superior precision. Scientists now have demonstrated that typical resonant designs provide a cross-axes wobble of less than 35 µrad. Thereby the device oscillates at 23 kHz 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.«