Study of polyvinylidene fluoride (PVDF) based bimorph actuators for laser scanning actuation at kHz frequency range

Abstract

This work focuses on some promising applications of polyvinylidene fluoride (PVDF) based bimorph actuators in microengineering. The actuator of several centimeters in length and 100μm in thickness takes advantage of the structural and electromechanical capabilities of the PVDF. These characteristics make the proposed PVDF based bimorph ideal for a laser scanner/switcher where high speed laser beam manipulation is feasible. This domain requires light and efficient actuators capable of actuating the mirror surface at kHz frequency range and having a weight of less than 200mg and volume of less than 150mm3. Analytical and finite element (FE) modeling were used to design the bimorph actuator with an attached mirror on the tip. Results of the modeling were also used to establish dimension criteria for the proposed bimorphs with an attached mirror. Some clean and gray room processing was needed to fabricate the bimorph actuators. Static and dynamic characterization was carried out to validate the response of the proposed actuator. Other bimorph based configurations were analyzed and compared to the proposed one. Results indicate that the PVDF bimorph actuator responds conveniently in a range up to 3kHz for beam scanning tasks. The same principle may be implemented to 2DoF actuators. Results obtained from modeling tools indicate a similar performance in terms of displacement. In addition, due to the intrinsic properties of the PVDF, the actuation system is compact which is advantageous for other domains such as biomedical and aerospace.