DocumentCode :
2915078
Title :
The MicroReed, an ultra-small passive MEMS magnetic proximity sensor designed for portable applications
Author :
Gueissaz, F. ; Piguet, D.
Author_Institution :
R&D Labs., Swatch Group, Marin, Switzerland
fYear :
2001
fDate :
25-25 Jan. 2001
Firstpage :
269
Lastpage :
273
Abstract :
A passive magnetostatic sensing MEMS device, similar to a reed switch, having a packaged volume of 2 mm/sup 3/ is described. It is capable of sensing the field of a 1 mm/sup 3/ SmCo magnet at a distance of more than 2 mm. The contact force between the microformed rhodium contact surfaces lies between 10 and 30 /spl mu/N, and contact resistances as low as 2 /spl Omega/ are measured. No contact sticking is observed. The device operation life extends to at least 200,000 cycles when packaged at wafer level with epoxy sealing. The device operation life increases to 100/spl times/10/sup 6/ cycles when measured on bare wafers in argon, showing that these MEMS sensors are intrinsically reliable in spite of the very low contact forces.
Keywords :
contact resistance; magnetic sensors; microsensors; portable instruments; MEMS magnetic proximity sensor; MicroReed; Rh; SmCo magnet; contact force; contact resistance; epoxy sealing; microformed rhodium contact surface; operation life; passive magnetostatic sensor; portable device; wafer level packaging; Contacts; Electrical resistance measurement; Force measurement; Magnetic devices; Magnetic switching; Magnetostatics; Microelectromechanical devices; Micromechanical devices; Packaging; Switches;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Micro Electro Mechanical Systems, 2001. MEMS 2001. The 14th IEEE International Conference on
Conference_Location :
Interlaken, Switzerland
ISSN :
1084-6999
Print_ISBN :
0-7803-5998-4
Type :
conf
DOI :
10.1109/MEMSYS.2001.906530
Filename :
906530
Link To Document :
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