103 research outputs found

    Powder blasting for three-dimensional microstructuring of glass

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    We report on powder blasting as a promising technology for the three-dimensional structuring of brittle materials. We investigate the basic parameters of this process, which is based on the erosion of a masked substrate by a high-velocity eroding powder beam, using glass substrates. We study the effect of various parameters on the etching rate, like the powder velocity and the mask feature size, which induces geometrical effects to the erosion process. We introduce oblique powder blasting and investigate, in particular, sidewall effects of the micropatterned structures. A few examples of devices micromachined by powder blasting are also presented. Keywords: Sand blasting; Powder blasting; Microfabrication; Erosion; Etchin

    A New Hybrid Technology for Planar Fluxgate Sensor Fabrication

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    We have adapted a new printed circuit board (PCB) technology to the fabrication of ultraflat and sensitive fluxgate magnetic field sensors. The two outer layers of the PCB stack compose the electrical windings of fluxgates, while the inner layer is made of a micro-patterned amorphous magnetic ribbon with extremely high relative magnetic permeability (µ_r=100 000). Two basic configurations were considered: one based on a toroidal magnetic core and the other on a rectangular core with and without an air gap. The field response and sensitivity of the fluxgate devices have been studied as a function of the gap length, the excitation current, and excitation frequency. Compared to fluxgate sensors of similar size, a relatively high sensitivity of 60 V/T was found at 30 kHz for a five-winding detection coil wound around a rectangular E-shaped magnetic core. This high performance is primarily attributable to the high-permeability magnetic core. The results clearly show the potential of this fluxgate device for application as a magnetic sensor

    Printed circuit board integrated fluxgate sensor

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    We have developed a cheap and simple trilayer printed circuit board (PCB)-based technology, adapted for the fabrication of fluxgate magnetic sensors. The two outer layers of the PCB stack comprise the electrical windings of the fluxgate, while the inner layer is made of patterned amorphous magnetic core with extremely high relative magnetic permeability (µr100,000). The output voltage and the sensitivity of the fluxgate devices have been studied as a function of the external field and of the geometry of the magnetic core. We have found a relatively high sensitivity of 18 V/T at an excitation current frequency of 10 kHz. The results obtained clearly show the potential of this miniaturised fluxgate device for application as a magnetic field sensor. Keywords: Fluxgate sensor; Sensitivity; High permeability; Compass; Vitrovac®; Printed circuit board (PCB

    A hybrid technology for miniaturised inductive device applications

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    We have fabricated two-dimensional inductive devices by integrating micropatterned magnetic foils of high permeability (µr=100000) with winding patterns realised in printed circuit boards (PCBs) and flex-foil technology. We realise relatively high inductances of 1-10 µH for transformer type devices and a sensitivity of 60 V/T at 30 kHz for fluxgate magnetic induction sensing devices. The same type of device is also used as a current sensor; here we typically find sensitivities of 10 mV/A for excitation currents of a few 100 mA. We think our technology opens the way to a new class of functional and economic sensing devices. Keywords: Planar transformer; Fluxgate sensor; Thin inductive devices; Current sensor; PCB technology; Flex-foil technolog

    The introduction of powder blasting for sensor and microsystem applications

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    We introduce powder blasting using a pressurised nozzle and a metallic mask as a new promising technology for microsystem fabrication. We study basic parameters of this powder blasting erosion process as well as mask-geometry effects on the erosion rate. We demonstrate the application potential of this technique in three important fields of microsystems research: (i) the realisation of microfluidic chips for biochemical separations, (ii) the micropatterning of composite hard magnetic layers for mechatronic and magnetic sensor applications, and (iii) the realisation of inertial sensors in glass. We present for the first time a mechanical and electrical characterisation of powder-blasted accelerometer devices. Keywords: Powder blasting; Microfabrication; Accelerometer; Erosio
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