Microelectro-mechanical chemical sensor
First Claim
1. A microelectronics based chemical sensor comprising:
- a first active beam having at least one end attached to a structure and a chemically selective material layer disposed on the first active beam;
excitation means for causing the first active beam to deflect;
a first resistor disposed on the first active beam, the first resistor having a resistance that changes responsive to a deflection of the first active beam; and
two reference cantilevered beams disposed on each side of the first active beam, each of the reference cantilevered beams having a resistor disposed thereon, wherein the first active beam and the reference cantilevered beams are arranged within a same aperture of the structure and extend in a same direction within the aperture,the first resistor on the first active beam and the resistors on the reference cantilevered beams being elements of a Wheatstone bridge,wherein an output of the Wheatstone bridge corresponds to an amount of a chemical sorbed by the material layer.
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Accused Products
Abstract
A microelectro-mechanical chemical sensor includes an active cantilever beam having a chemically selective material layer disposed thereon and at least one, preferably two, resistors with the resistance corresponding to the cantilever beam deflection. The sensor also has at least two, and preferably four, auxiliary cantilever beams adjacent to the active cantilever and attached to the same substrate, each having a piezoresistor disposed thereon. The piezoresistors are elements of a Wheatstone bridge, and the Wheatstone bridge output indicates the amount of a predetermined target chemical sorbed by the chemically selective material layer. The sensor is electrostatically actuated in order to monitor the resonant frequency.
43 Citations
24 Claims
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1. A microelectronics based chemical sensor comprising:
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a first active beam having at least one end attached to a structure and a chemically selective material layer disposed on the first active beam; excitation means for causing the first active beam to deflect; a first resistor disposed on the first active beam, the first resistor having a resistance that changes responsive to a deflection of the first active beam; and two reference cantilevered beams disposed on each side of the first active beam, each of the reference cantilevered beams having a resistor disposed thereon, wherein the first active beam and the reference cantilevered beams are arranged within a same aperture of the structure and extend in a same direction within the aperture, the first resistor on the first active beam and the resistors on the reference cantilevered beams being elements of a Wheatstone bridge, wherein an output of the Wheatstone bridge corresponds to an amount of a chemical sorbed by the material layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A microelectronics based chemical sensor comprising:
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an electrostatically actuated first cantilever beam attached at one end to a structure, the first active beam having a chemically selective material layer disposed thereon; at least a first resistor disposed on the first cantilever beam, the first resistor having a resistance corresponding to a deflection of the first cantilever beam, a second cantilever beam having a second resistor disposed thereon, the second cantilever beam attached at an end to the structure on one side of the first cantilever beam; a third cantilever beam having a third resistor disposed thereon, the third cantilever beam attached at an end to the structure between the first cantilever beam and the second cantilever beam; a fourth cantilever beam having a fourth resistor disposed thereon, the fourth cantilever beam attached at an end to the structure at an opposite side of the first cantilever beam; and a fifth cantilever beam having a fifth resistor disposed thereon, the fifth cantilever beam attached at an end to the structure between the first cantilever beam and the fourth cantilever beam; the first, second, third, fourth and fifth resistors being elements of a Wheatstone bridge, a measuring arm of the Wheatstone bridge comprising the first resistor, a reference arm of the Wheatstone bridge comprising the second and fourth resistors in series, and another reference arm of the Wheatstone bridge comprising the third and fifth resistors in series, the output of the Wheatstone bridge corresponding to the amount of an analyte sorbed by the chemically selective material layer. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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Specification