20 April 1998 Variable-focal-length microelectromechanical lens
Author Affiliations +
We discuss the characteristics of a novel microelectromechanical cylindrical focusing mirror having a focal length which is controlled by active and intrinsic stresses in the thin films composing it. The unactuated mechanical state of the mirror is determined by intrinsic stress levels in a SiN structural layer and a piezoelectric PZT actuator layer which are part of a doubly clamped cantilever beam. The stresses are controlled by the sputter- deposition parameters and annealing conditions. The stresses concentrate curvature in the thin central mirror portion of the beam and can give the mirror a minimum focal length of as little as 100 micrometers . The focal length is increased during actuation of the PZT layer by inducing a differential tensile stress which reduces the curvature. Theoretical results are presented which predict the maximum focal length range and operating speed for a given device design. They indicate that operating frequencies of greater than 100 kHz can be achieved for a device with a focal length range of 100 micrometers to infinity. Experimental results will verify the operating principal of the proposed device.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Mark J. Mescher, Mark J. Mescher, Michael L. Reed, Michael L. Reed, Tuviah E. Schlesinger, Tuviah E. Schlesinger, } "Variable-focal-length microelectromechanical lens", Proc. SPIE 3289, Micro-Optics Integration and Assemblies, (20 April 1998); doi: 10.1117/12.305482; https://doi.org/10.1117/12.305482

Back to Top