Micromachined strain sensor

A micromachined strain sensor comprising:

• (a) a substrate with a surface;
• (b) a microstructural beam member anchored to the substrate at one end and having a portion extending over the surface of the substrate;
• (c) at least one electrically conductive displaceable tine;
• (d) at least one electrically conductive mating tine mounted to the substrate closely adjacent to a displaceable tine to define adjacent tines such that a capacitor is formed between the adjacent tines;
• and,
• (e) a support beam to which the at least one displaceable tine is mounted, wherein the beam member is a first beam member which extends from an anchor mount secured to the substrate to join to the support beam at a position along a side of the support beam, a second beam member extending from an anchor mount secured to the substrate to join the support beam on a side of the support beam opposite to the side to which the first beam member is joined and at a position spaced longitudinally from the position at which the first beam member joins the support beam, whereby expansion or contraction of the first and second beam members will rotate the support beam about a pivot position between the positions at which the beam members join the support beam to displace the at least one displaceable tine so as to bring the at least one displaceable tine closer to or further from the adjacent mating tine.

A micromachined strain sensor comprising:

• (a) a substrate with a surface;
• (b) a microstructural beam member anchored to the substrate at one end and having a portion extending over the surface of the substrate;
• (c) a plurality of electrically conductive displaceable tines;
• and
• (d) a plurality of electrically conductive mating tines each mounted to the substrate closely adjacent to a displaceable tine to define adjacent tines such that a capacitor is formed between the adjacent tines, wherein the beam member is a first beam member that extends from an anchor mount secured to the substrate to join a support beam at one end of the support beam, and including a second beam member shorter than the first beam member extending from an anchor mount secured to the substrate to another end of the support beam, the displaceable tines mounted to the support beam, and the mating tines mounted to the substrate adjacent to the displaceable tines, such that expansion or contraction of the beam members causes the first beam member to expand or contract more than the second beam member and to thereby rotate the support beam in one direction or another to displace the displaceable tines so as to bring the displaceable tines closer to or further from the mating tines.

A micromachined strain sensor comprising:

• (a) a substrate with a surface;
• (b) a microstructural beam member anchored to the substrate at one end and having a portion extending over the surface of the substrate;
• (c) a plurality of electrically conductive displaceable tines;
• and
• (d) a plurality of electrically conductive mating tines each mounted to the substrate closely adjacent to a displaceable tine to define adjacent tines such that a capacitor is formed between the adjacent tines, wherein the beam member is a first beam member that extends from an anchor mount secured to the substrate to join a support beam at one end of the support beam, and including a second beam member shorter than the first beam member extending from an anchor mount secured to the substrate to another end of the support beam, the displaceable tines mounted to the support beam, and the mating tines mounted to the substrate adjacent to the displaceable tines, such that expansion or contraction of the beam members causes the first beam member to expand or contract more than the second beam member and to thereby rotate the support beam in one direction or another to displace the displaceable tines so as to bring the displaceable tines closer to or further from the mating tines;
• and
• (e) a sacrificial layer formed on the surface of the substrate on which the beam members, support beam, and displaceable tines are deposited.

A micromachined strain sensor comprising:

• (a) a substrate with a surface;
• (b) an elongated support beam disposed above the surface of the substrate to define a longitudinal direction along the support beam;
• (c) two pairs of microstructural beam members anchored to the substrate at one end and having a portion extending over the surface of the substrate, the two pairs of beam members joined to two ends of the support beam at an acute angle to form a V-shape and such that the V-shapes formed by the two pairs of beam members are aligned, each beam member extending from an anchor mount secured to the substrate to a position at which each beam member is joined to the support beam such that expansion or contraction of the beam members displaces the support beam longitudinally;
• (d) a plurality of electrically conductive displaceable tines formed with and extending outwardly from opposite sides of the elongated support beam over the surface of the substrate;
• and
• (e) a plurality of electrically conductive mating tines mounted to the substrate and extending toward the displaceable tines on each side of the support beam, each mating tine adjacent to a displaceable tine to define adjacent tines, such that capacitors are formed between adjacent tines.

A micromachined strain sensor comprising:

• (a) a substrate with a surface;
• (b) a plurality of adjacent displaceable structures each comprising:
• (1) an elongated support beam disposed above the surface of the substrate to define a longitudinal direction along the support beam;
• (2) two pairs of microstructural beam members anchored to the substrate at one end and having a portion extending over the surface of the substrate, the two pairs of beam members joined at two ends of the support beam at an acute angle to form a V-shape and such that the V-shapes formed by the two pairs of beam members are aligned, each beam member extending- from an anchor mount secured to the substrate to a position at which each beam member is joined to the support beam such that expansion or contraction of the beam members displaces the support beam longitudinally;
• (3) a plurality of electrically conductive displaceable tines formed with and extending outwardly from opposite sides of the elongated support beam over the surface of the substrate, each mating tine adjacent to a displaceable tine to define adjacent tines such that capacitors are formed between adjacent tines;
• and
• wherein the displaceable structures include one central displaceable structure formed with the pairs of beam members extending from the anchor mounts of the beam members to the support beam in a first longitudinal direction and two adjacent displaceable structures having the pairs of beam members extending from the anchor mounts of the beam members to the support beam in a second longitudinal direction that is opposite to the first longitudinal direction, wherein the displaceable tines on each side of the support beam of the central displaceable structure are closely adjacent to the displaceable tines on the support beam of the adjacent displaceable structures that are adjacent to the central displaceable structure, such that the support beam of the central displaceable structure displaces in one direction in response to built-in strain in the beam members supporting that support beam while the support beams of the adjacent displaceable structures are displaced in the opposite direction.

A method of sensing strain in a microstructural material comprising the steps of:

• (a) providing a substrate with a sacrificial layer thereon;
• (b) depositing a microstructural beam member on the sacrificial layer and anchoring the beam member to the substrate at one end thereof;
• (c) connecting at least one electrically conductive displaceable tine to the beam member such that the at least one displaceable tine can displace with the beam member;
• (d) forming at least one electrically conductive mating tine mounted to the substrate closely adjacent to the displaceable tine to define adjacent tines such that a capacitor is formed between the adjacent tines;
• (e) removing the sacrificial layer to allow the beam member to displace by expansion or contraction of the beam member as a result of strain in the beam member and to displace the displaceable tine connected to the beam member;
• and
• (f) measuring a change in capacitance between the displaceable tine and the mating tine that occurs as a result of removing the sacrificial layer whereby the built-in strain in the beam member can be determined from the measured change in capacitance.