Date of Award

Fall 2004

Document Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Micro and Nanoscale Systems

First Advisor

Kody Varahramyan

Abstract

A novel polymer-based integrated wide-angle dynamic micro-optical lens system that can provide variable focal length and field of view (FOV) with large numerical aperture is designed, fabricated, and tested for its optical characteristics.

Initial experiments were conducted using static glass lenses to test for configuration of lenses that could provide wide FOV. From these initial experiments, it was found that the higher FOV could be achieved with double concave (DCV) lenses compared to double convex (DCX) lenses of the same focal length. Further, it was observed that increasing the number of DCV lenses increases FOV. Thus, an integrated dynamic polymer microlens system has been fabricated with two or three DCV lenses, which demonstrates a wide range of tunable focal length and FOV. A flexible polydimethylsiloxane (PDMS) polymer membrane is used to form the lens surface. Two such membranes with a fluidic lens chamber are actuated by fluidic pressure to form either a DCX or DCV lens. The curvature of the lens (PDMS membrane) changes because of the fluidic pressure built by a syringe pump and produces the change in the focal length and FOV without any mechanical moving parts. The relationship between the focal length and FOV of the dynamic microlens system with respect to the change in volume of the fluid pumped in or out of the lens chamber has been investigated and reported.

Experimental results show that a focal length in the range of several hundred microns to several millimeters and the smallest f-number equal to 0.76, which corresponds to a numerical aperture of 0.55, could be achieved using a single dynamic microlens system. It was observed that the FOV in the range of 0.12 to 61.08 degrees and 7 to 68.22 degrees could be achieved by actuating a single dynamic microlens system, as a DCX and DCV lens. It was also observed that the FOV could be tuned in the range of 8 to 79.65 degrees and 11.49 to 90.44 degrees, by using integrated dynamic microlenses with two or three DCV lenses, respectively. (Abstract shortened by UMI.)

Download

Share

COinS