Thermal Actuated Solid Tunable Lens

In this letter, the concept of driving tunable solid lens using microthermal actuator is presented. This microoptical device is composed of a flexible polydimethylsiloxane (PDMS) lens, silicon conducting ring, and silicon heater. The mismatching of coefficient of thermal expansion and stiffness between PDMS and silicon will lead to the deformation of polymer lens during heating, so as to further change its focal length. To demonstrate the feasibility of this approach, a microfabrication processes have been established to monolithically fabricate the present microoptical device. The typical experiment results show that the tunable focal length was up to 834 mum with an input current of 70 mA