3 research outputs found

    Microlamination Based Lumped And Distributed Magnetic Mems Systems Enabled By Through-Mold Sequential Multilayer Electrodeposition Technology

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    Microfabricated magnetic MEMS components such as permanent micromagnets and soft magnetic structures are key enablers in various lumped and distributed systems such as energy harvesters, magnetometers, biomagnetic filters, and electromagnetic micromotors. The unique functionalities of such systems often require designers to controllably scale the relevant dimensions of a device relative to the characteristic length of a targeted application. We demonstrate in this dissertation that the developed Microlamination Technology could create two-dimensional uniform- or dual- height monolithic metallic structures with additional deterministic structural and compositional complexities along thickness direction, suitable to facilely and flexibly fabricate both lumped and distributed magnetic MEMS systems at a designer\u27s will. The utility of the Microlamination Technology is further validated through the realization of two exemplary systems based on this technology: (i) A lumped system of laminated permanent micromagnets. Microfabricated permanent magnets possessing a multilayer structure enabled by the Microlamination Technology that preserves the high energy density of thinner magnetic films, while simultaneously reducing average residual stress of the films and achieving a significant thickness are presented. The key to retain the superior magnetic properties of thin films in thick laminations is the low interface roughness between the layers, which in turn improves the coercivity of the micromagnets. (ii) A distributed system of a bi-stable vertical magnetic actuator with non-contact latching. The utilization of the Microlamination Technology translates the structural periodicity (multilayer) into magnetic-field-pattern periodicity, which in turn enables the bi-stability of the microsystem and leads to the defined latching behavior. The latching mechanism is solely based on the magneto-static interaction without the need of a mechanical stop. No external energy is needed in the latching positions. This vertical bi-stable actuator could have potential applications as valves in micro-fluidic controls, and as integral parts of micro-mirrors in optical applications

    Polymer NdFeB Hard Magnetic Scanner for Biomedical Scanning Applications

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    Micromirror scanners are the most significant of the micro-optical actuator elements with applications in portable digital displays, automotive head-up displays, barcode scanners, optical switches and scanning optical devices in the health care arena for external scanning diagnostics and in vivo scanning diagnostics. Recent development in microscanning technology has seen a shift from conventional electrostatic actuation to electromagnetic actuation mechanisms with major advantages in the ability to produce large scan angles with low voltages, remote actuation, the absence of the pull-in failure mode and the acceptable electrical safety compared to their electrostatic counterparts. Although attempts have been made to employ silicon substrate based MEMS deposition techniques for magnetic materials, the quality and performance of the magnets are poor compared to commercial magnets. In this project, we have developed novel low-cost single and dual-axis polymer hard magnetic micromirror scanners with large scan angles and low power consumption by employing the hybrid fabrication technique of squeegee coating to combine the flexibility of polydimethylsiloxane (PDMS) and the superior magnetic performance of fine particle isotropic NdFeB micropowders. PCB coils produce the Lorentz force required to actuate the mirror for scanning applications. The problem of high surface roughness, low radius of curvature and the magnetic field interaction between the gimbal frame and the mirror have been solved by a part PDMS-part composite fabrication process. Optimum magnetic, electrical and time dependent parameters have been characterized for the high performance operating conditions of the micromirror scanner. The experimental results have been demonstrated to verify the large scan angle actuation of the micromirror scanners at low power consumption
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