Sensor apparatus with magnetically deflected cantilever
AssigneeSwiss Federal Institute of Technology Zurich
InventorsDirk Lange, Christoph Hagleitner, Oliver Brand
Life of this patent
Estimating the term…
Abstract
A magnetically excited, resonant cantilever sensor apparatus has a cantilever as the transducer element. A static magnetic field is directed in the plane of the cantilever(s) cooperating with a current loop in/on the latter. Orienting the magnetic field along or perpendicular to the cantilever axis and controlling the current apprpriately allows for selective excitation of resonance or non-resonance modes and/or in a self-oscillation mode. The deflection of the cantilever is detected using piezoresistive or magnetic readout. The apparatus may be used as gas sensor, scanning force microscope, mechanical filter, temperature sensor or the like.
Claims16
A sensor apparatus, comprising a cantilever, an associated magnetic energizing system for deflecting said cantilever, and a deflection detector, comprising in combination
- a static magnetic field external to said cantilever, a magnetic vector of said field extending in plane with said cantilever's longitudinal extension,
- a conductor loop on or in said cantilever for an electric current,
- means for energizing said conductor loop with an electrical current for exciting mechanical deflections of said cantilever, and
- means for detecting a deflection of said cantilever integrated onto or into said cantilever.
A cantilever for a sensor apparatus, for mass-sensitive detection,
- said cantilever having a fixed end and a free end and being of variable stiffness along its longitudinal extension,
- having a stiffer section close to the fixed end and a not so stiff section close to said free end, said fixed end being equipped for attachment to said sensor apparatus, said free end serving as a sensing section when its mass is changed,
- said cantilever in a sensor apparatus comprising said cantilever, an associated magnetic energizing system for deflecting said cantilever, and a deflection detector,
- comprising in combination
- a static magnetic field external to said cantilever a magnetic vector of said magnetic field extending in plane with said cantilever's longitudinal extension,
- a conducting loop on or in said cantilever for an electric current,
- means for energizing said conductor with an electrical current, thereby exciting mechanical deflections of said cantilever, and
- means for detecting a deflection of said cantilever integrated onto or into said cantilever.
Dependencies are inferred from the claim text.