Solar energy-actuated back and forth optical mechanism

A self-active back and forth motion mechanism for optical systems was designed and realized without electrical power consumption. The system utilized the beam converging feature and thermal heating performance of lenses in combination with the thermal-based phase-changing feature of a shape memory alloy (SMA) actuator. Prototype 1 was designed and fabricated with a fixed lens group and a movable lens group, and its feasibility was confirmed through experiments. An optimized focusing pattern suitable for the SMA actuator was realized by employing a cylindrical Fresnel lens, and prototype 2 was built using a simplified fabrication method. We believe that our design is economical and environment friendly. A few potential applications can be optical/mechanical switches for solar energy panels, control units for outdoor equipment, and solar power chargers.