Abstract
We describe a technique for analyzing the mechanical and optical properties of deformable optical elements that combines the finite element method, ray-tracing and birefringence measurement. We fabricated a pneumatically actuated microlens array on an elastic polydimethylsiloxane (PDMS) film to assess the proposed analysis technique. The lenses are 120 μm in diameter and arranged on the top surface of a 200 μm thick base film. The lenses are displaced by pneumatic actuators at the bottom of the film. The measured mechanical–optical properties of the PDMS test materials showed a good match with the calculation. The paths and retardation of light beams transmitted in the microlens array under several actuating conditions were then analyzed. The lens displacement of 21.8 μm was measured at an applied pressure of −45 kPa. At the same pressure, a ray-trace analysis showed that the actuator changed the visual axis of each lens by 5°, while the retardation was estimated to be within the order of 5 × 10−3 nm.