Design, fabrication and testing of a micromachined integrated tunable microlens

Abstract

An integrated tunable microlens chip capable of adjusting its focal length over a wide range without any mechanical driving parts is reported in this paper. The packaged microlens chip consists of a flexible polymer lens, a fluidic chamber, a thermal actuator and a sensor. The focal length change is controlled by varying the voltage applied to the thermal actuator. The focal length can be changed from 14.658 mm to 2.782 mm, which corresponds to the change of numerical aperture from 0.078 to 0.412. The tunable microlens chip is a critical device to increase the efficiency of the image capture and the light detection in optical or biophotonic applications. Potential applications include camera phones, surveillance cameras, disk recording systems, collimators, optical sensing systems, confocal imaging systems and optical communications.