Large deflection of out-of-plane magnetic actuators using surface micromachining

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)22_Publication in policy or professional journal

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Original languageEnglish
Pages (from-to)140-147
Journal / PublicationProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 2000
Externally publishedYes


TitleMicromachined Devices abd Components VI
CitySanta Clara, CA, USA
Period18 - 19 September 2000


A magnetic actuator with torsional-polysilicon flexures, capable of very large out-of-plane displacement (the order of 1 mm), and individually controlled with integrated coils that will be discussed in this paper. Magnetic actuator uses coils to produce the magnetic field required for individual microactuator motion, while the off-chip magnetic actuates unclamped devices. The advantages of the actuators are exploited: large deflections are achieved using magnetic forces to actuate compliant microflexure structures; Actuation is achieved using magnetic fields generated by off-chip sources; The actuating force is applied in a conducting environment such as a saline fluid. Individually prototype-torsional actuators are deflected over 70° out of the plane of the wafer, when a current of 100 mA flows through a twenty-turn coil integrated into each actuator. The magnetic actuator provides an interaction force of several tens μN between the coil-driven and the off-chip magnetic field. The micro actuators are capable of achieving large deflections (100 s of μm) in stationary air and fluid dynamic flow. A completed model of static mechanical and magnetic is built up to characterize mechanical properties including angular deflection, vertical deflection, bending stresses of thin plate. Both the coil-driven and the actuator structure are constructed in polysilicon surface micromachining process.