This paper reports a novel large vertical displacement (LVD) microactuator that can generate large piston motion and bi-directional scanning at low driving voltage. A LVD micromirror device has been fabricated by using a unique deep reactive ion etch (DRIE) post-CMOS micromachining process that simultaneously provides thin-film and single-crystal silicon microstructures. The bimorph actuation structure is composed of aluminum and silicon dioxide with an embedded polysilicon thermal resistor. With a size of only 0.7 mm × 0.32 mm, the LVD micromirror demonstrated a vertical displacement of 0.2 mm at 6 V dc. This device can also be used to perform bi-directional rotational scanning through the use of two bimorph actuators. The micromirror rotates over ±15 ◦ at less than 6 V dc, and over ±43 ◦ (i.e., >170 ◦ optical scan angle) at its resonant frequency of 2.6 kHz.

A thermal bimorph micromirror with large bi-directional and vertical actuation

This topical review discusses magnetic microelectromechanical systems (MagMEMS). A number of exemplars are drawn from the authors' own work, and a review is given of other significant literature in the area. The case is made that MagMEMS offer unique features over conventional MEMS, such as remote interrogation and self-test. A review of the key magnetic principles and magnetic materials is included by way of a guide to the general reader. Finally, a roadmap for the future development of MagMEMS is set out.

https://iopscience.iop.org/article/10.1088/0022-3727/37/22/R01/pdf

Magnetic materials for MEMS applications

Ground-based telescopes suffer from atmospheric turbulences which perturb the quality of the light arriving from space. Astronomers use adaptive optics in order to correct the wavefront of oncoming light. In this context, a prototype of electromagnetic miniature (O 50 mm) deformable mirror is developed, using available microtechnologies. The mirror is composed of a thin polymer membrane (2–5 μm) covered with a matrix of permanent magnets, and of an array of planar microcoils on a O 50 mm substrate. The paper presents the various technologies used to build the actuator (membranes, coils, magnets). The mechanical behaviour of the mirror is tested. Deformations of up to 20 μm are achieved with currents in the range 1–3 A (6.6 μm/A). Resonance occurs at 485 Hz, with good linearity up to 200 Hz.

Deformable magnetic mirror for adaptive optics: technological aspects

We present a micromachined mirror array for use in adaptive optics. Piston motions of more than 6 µm as well as tip/tilt motions of 11 mrad (0.65°) are demonstrated. Single-crystal-silicon mirrors are assembled onto electrostatic parallel-plate actuators. The actuators lift off the substrate after microstructure release as a consequence of residual stresses in nickel-polysilicon bimorph flexures. The assembled mirrors provide fill factors of 95%. Peak-to-valley surface variations are smaller than 30 nm over a 464 µm-diameter (vertex-to-vertex) mirror segment.

Micromirrors for Adaptive-Optics Arrays

Abstract Nanostructures are widely used in nano and micro-sized systems and devices such as biosensors, nano actuators, nano-probes, and nano-electro-mechanical systems. The complete understanding of the mechanical behavior of nanostructures is crucial for the design of nanodevices and systems. Therefore, the flexural, stability and vibration analysis of various nanostructures such as nanowires, nanotubes, nanobeams, nanoplates, graphene sheets and nanoshells has received a great attention in recent years. The focus has been made, to present the structural analysis of nanostructures under thermo-magneto-electro-mechanical loadings under various boundary and environmental conditions. This paper also provides an overview of analytical modeling methods, fabrication procedures, key challenges and future scopes of development in the direction of analysis of such structures, which will be helpful for appropriate design and analysis of nanodevices for the application in the various fields of nanotechnology.

/pdf/advances-in-modelling-and-analysis-of-nano-structures-a-5bn6kqz5s1.pdf

Advances in modelling and analysis of nano structures: a review

An alternative approach to compact deformable mirrors for adaptive optics is developed A prototype of a two inch mirror composed of a thin polymer membrane covered with a matrix of permanent magnets and an array of microcoils was built Several complementary modelling tools were used to study the behaviour of the device Promising first results show regular deformations of up to 20 /spl mu/m, a good linearity and a bandwith of 200 Hz This novel technology should enable higher resolution with smaller, lighter integrated mirrors

C. Divoux

Papers

Deformable magnetic mirror for adaptive optics: technological aspects

Deformable magnetic mirror for adaptive optics: first results