An electrothermal microlens scanner with low-voltage large-vertical-displacement actuation

This letter reports the design, fabrication, and operation of a microlens scanner that can perform large vertical scans at low actuation voltages. Photoresist (PR) reflow technique was used to form a 210-μm-diameter PR microlens on a lens holder which is integrated with a large-vertical-displacement (LVD) microactuator. The lens holder is fabricated using a maskless deep-reactive-ion-etch complementary-metal- oxide-semiconductor microelectromechanical systems process. A maximum static vertical displacement of 280/μm is achieved with a 700 by 320 μm LVD device at a low actuation voltage of 10 V. The microlens has a focal length of 188 μm, a numerical aperture of 0.35, and a resonant frequency of about 1 kHz.