Out-of-Plane Long-Range Operated Soft Engine with Driving Stretchable Zone Plate and Led Abilities for Tunable Focused Therapeutic Ultrasonic and Infrared Heating Applications

This paper presents a soft engine which performs the long-range up-and-down motion with four planar film-structured electroactive polymer (EAP) actuators. The engine can dynamically tune the focus of ultrasonic beam by driving the foil-made stretchable Fresnel zone plate with out-of-plane motion. Moreover, the micromachined buckles and serpentine structure were utilized to convert the bending motion of a pair of actuators to the linear motion along with lighting up the light-emitting diode (LED). We successfully demonstrate that the developed device stretches the zone plate to tune the focal point of the ultrasonic beam up to 4 mm. Also, controlling the LED to turn on and off in a moving cycle of the soft engine is displayed.