The growing availability of commercial foundry processes allows easy implementation of micro-opto-electro-mechanical systems (MOEMS) for a variety of applications. Such applications go beyond single devices to include whole optical systems on a chip, consisting of mirrors, gratings, Fresnel lenses and shutters, for example. Hinged and rotating structures, combined with powerful and compact thermal actuators, provide the means for positioning and operating these optical components. This paper presents examples of such systems built in a commercial polycrystalline silicon surface-micromachining process, the ARPA-sponsored Multi-User MEMS ProcesS (MUMPS). Examples range from optical sub-components to large mirror arrays, communication components, and micro-interferometers. Using the examples discussed in this paper, a designer can take advantage of commercially available surface-micromachining processes to design and develop MOEMS without the need for extensive in-house micromachining capabilities.

Recently, torque-transmission one-way tip articulated fiberscopes with a working channel have been developed. With this type of scopes, force is transmitted from the operator's hands to the tip of the fiberscope to obtain an adequate field of view. Micro actuators are expected to increasingly replace the operator's hands. Shape memory alloy (SMA) coil spring actuators are well suited to this purpose because of their large displacement compared with conventional actuators. In the fabrication of SMA coil springs, we examined fabrication conditions such as the tension and pitch of the SMA wire. As a result, we have successfully fabricated coil springs with a minimum outer diameter of 76 µm. SMA wire 25 µm in diameter and stainless steel wire 30 µm in diameter were used. As an application using SMA actuators, an active fiberscope (using an image guide fiber with 4200 pixels and light guide fibers) 2 mm in outer diameter with SMA actuators was designed and fabricated. We investigated the mechanical properties of the bending part in designing the SMA actuators. The specifications of the SMA coil springs are determined by the displacement and the force required of the pull wire. The relationship between the displacement of the pull wire and the number of windings of the SMA coil spring was calculated. The effective number of windings of SMA coil spring was found to be seventeen when using wire of 0.3 mm in diameter. The tip of the fiberscope was bent approximately 60 degrees and returned to the straight position when a current was applied to each of the SMA coil springs. A clear picture of the fiberscope which followed the tip bending operation could be received on the monitor. This SMA actuator can be easily extended for bending in many directions by configuring several of these mechanisms.

A method is presented for implementing a neural control system for controlling a piezopolymer bimorph flexible micro-actuator. Two neural controllers were constructed, both with an adaptive-type neural identifier and a learning-type direct or open-loop neural controller, focusing on the difference in learning speed between the adaptive and learning schemes. Simulated use of the proposed controllers to control a flexible micro-actuator showed that they can do so effectively. Experiments also demonstrated that a neural controller can be used to control a flexible micro-actuator.