Low-Power Liquid Lens Having Si Cylinder Chamber for Capsule Endoscope

摘要

The liquid lens based on MEMS technology can be an appropriate solution to improve the imaging capability of a capsule endoscope because it can be realized small enough and also consume negligible power. In this paper, a cylinder-type liquid lens was designed to minimize the dead area and then fabricated with MEMS technology combining the silicon thin-film process and the wafer bonding process where the multiple dielectric layer of Teflon, silicon nitride and thermal oxide was formed on the cylinder wall. The focal length of the lens module including the fabricated liquid lens was changed reproducibly as a function of the applied voltage. With the change of 30V in the applied bias, the focal length of the constructed lens module could be tuned in the range of about 42cm. The fabricated liquid lens was also proven to be small enough to be adopted in the capsule endoscope, which means the liquid lens can be utilized for the imaging capability improvement of the capsule endoscope.