Quick search Find article
Quick search
Find article

Comb-drive actuators for large displacements

Rob Legtenberg, A W Groeneveld and M Elwenspoek

Show affiliations


The design, fabrication and experimental results of lateral-comb-drive actuators for large displacements at low driving voltages is presented. A comparison of several suspension designs is given, and the lateral large deflection behaviour of clamped - clamped beams and a folded flexure design is modelled. An expression for the axial spring constant of folded flexure designs including bending effects from lateral displacements, which reduce the axial stiffness, is also derived. The maximum deflection that can be obtained by comb-drive actuators is bounded by electromechanical side instability. Expressions for the side-instability voltage and the resulting displacement at side instability are given. The electromechanical behaviour around the resonance frequency is described by an equivalent electric circuit. Devices are fabricated by polysilicon surface micromachining techniques using a one-mask fabrication process. Static and dynamic properties are determined experimentally and are compared with theory. Static properties are determined by displacement-to-voltage, capacitance-to-voltage and pull-in voltage measurements. Using a one-port approach, dynamic properties are extracted from measured admittance plots. Typical actuator characteristics are deflections of about at driving voltages around 20 V, a resonance frequency around 1.6 kHz and a quality factor of approximately 3.


PACS

85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices

81.20.Wk Machining, milling

46.70.De Beams, plates and shells

89.20.Kk Engineering

46.25.-y Static elasticity

Subjects

Electronics and devices

Condensed matter: structural, mechanical & thermal

Nanoscale science and low-D systems

Dates

Issue 3 (September 1996)

Received 30 November 1995, accepted for publication 4 June 1996



View by subject




Export








Please login to access our web services, or create an account if you don't yet have one.

You must have cookies enabled in your web browser to be able to login.

Username
Password

Forgotten your password? Get a new one here.