Inspired by nature, many application domains might gain from combining the multi-channel design of the compound eyes of insects and the refocusing capability of the human eye in one compact configuration. Multi-channel refocusing imaging systems are nowadays only commercially available in bulky and expensive designs since classical refocusing mechanisms cannot be integrated in a miniaturized configuration. We designed a wafer-level multi-resolution two-channel imaging system with refocusing capabilities using a voltage tunable liquid lens. One channel is able to capture a wide field-of-view image (2x40 degrees) of a surrounding with a low angular resolution (0.078 degrees), whereas a detailed image of a small region of interest (2x7.57 degrees) can be obtained with the high angular resolution channel (0.0098 degrees). The latter high angular resolution channel contains the tunable lens and therefore also the refocusing capabilities. In this paper, we first discuss the working principle, tunability and optical quality of a voltage tunable liquid lens. Based on optical characterization measurements with a Mach-Zehnder interferometer, we designed a tunable lens model. The designed tunable lens model and its validation in an imaging setup show a diffraction-limited image quality. Following, we discuss the performance of the designed two-channel imaging system. Both the wide field-of-view and high angular resolution optical channels show a diffraction-limited performance, ensuring a good image quality. Moreover, we obtained an improved depth-of-field, from 0.254m until infinity, in comparison with the current state-of-the art published wafer-level multi-channel imaging systems, which show a depth-of-field from 9m until infinity.
|Conference||SPIE Optics, Photonics, and Digital Technologies for Multimedia Applications III|
|Periode||16/04/14 → 17/04/14|