A Millimeter-Tunable-Range Microlens for Endoscopic Biomedical Imaging Applications

We report an electrothermally-actuated microlens scanner that is suitable for biomedical imaging applications. The microlens has a large tunable range and a low driving voltage, and the lens is made of glass. The enabling device is a new electrothermal actuator design that is capable of large vertical actuation (similar to 0.9 mm) on a 3 mm device footprint, with small lateral shift (<7 mu m) and tilting (<0.38 degrees) at less than 4-V. The design, fabrication and characterization of the actuator are presented. Imaging results by the assembled microlens are also demonstrated.