Variable-focus cylindrical lens based on a PDMS substrate

The variable-focus cylindrical lens based on a Polydimethylsiloxane(PDMS) chip is designed and fabricated,which is composed mainly by a glass capillary embedded in a soft PDMS chip,and the focal length varies by selecting different liquids filled into the glass capillary.When the refractive index of liquid changes in the range of 1.451 8 to 1.550 2,the focal length varies from 21.369 to 3.362 mm,which reaches a 6.4× zoom ratio.With light-scattering imaging method,the ray traces of parallel light passing through various lenses are viewed and photographed.The imaging processes are simulated by using the ZEMAX optical design software,and the simulated results are consistent with the experimental photographs.The focal length formula of a glass capillary buried in PDMS chip is derived with the Gaussian optical successive imaging method,and is verified by the simulated method and experimental results.The successful fabrication of the variable-focus cylindrical lens based on PDMS substrate provides an important optical imaging element for "lab on a chip".