Sensor with silicon strain gage
First Claim
1. A sensing structure comprising:
- a metal body having a diaphragm, the metal body having an edge formed by an abrupt change in thickness of the metal body in a direction normal to the diaphragm, the edge defining a boundary of the diaphragm;
a silicon chip secured to the metal diaphragm, the silicon chip comprising a strain-sensing element aligned with the edge of the body in the direction normal to the diaphragm, whereby movement of the diaphragm induces strain in the silicon chip that is concentrated at the strain-sensing element of the silicon chip; and
the silicon chip having a surface facing the metal body, the silicon chip having a groove in the surface so as to be between the strain-sensing element and the metal body, the groove causing the strain induced in the silicon chip by movement of the diaphragm to be further concentrated at the strain-sensing element of the silicon chip.
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Accused Products
Abstract
A media-compatible sensing structure (210) that employs strain-sensing elements (222) formed in or on a silicon chip (212). The sensor (210) generally includes a metal body (214) having a diaphragm (216) and an edge (226) formed by an abrupt change in the thickness of the metal body (214) in a direction normal to the diaphragm (216). The silicon chip (212) is secured directly to the metal diaphragm (216) and has at least one strain-sensing element (222) aligned with the edge (226) of the body (214) in the direction normal to the diaphragm (216), such that movement of the diaphragm (216) induces strain in the silicon chip (212) that is localized at the strain-sensing element (222). The chip (212) preferably includes a groove (234) in its surface (212) facing the diaphragm (216) and between the strain-sensing element (222) and the metal body (214), such that strain induced in the chip (212) by movement of the diaphragm (216) is further concentrated in the region of the chip (212) containing the strain-sensing element (222). The chip (212) is preferably attached to the metal diaphragm (216) with a bonding material (236). To promote adhesion of the chip (212) to the diaphragm (216), the chip (212) preferably has recesses (240) in its surface facing the diaphragm (216) to create an interlocking effect between the bonding material (236) and the chip (212).
27 Citations
20 Claims
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1. A sensing structure comprising:
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a metal body having a diaphragm, the metal body having an edge formed by an abrupt change in thickness of the metal body in a direction normal to the diaphragm, the edge defining a boundary of the diaphragm; a silicon chip secured to the metal diaphragm, the silicon chip comprising a strain-sensing element aligned with the edge of the body in the direction normal to the diaphragm, whereby movement of the diaphragm induces strain in the silicon chip that is concentrated at the strain-sensing element of the silicon chip; and the silicon chip having a surface facing the metal body, the silicon chip having a groove in the surface so as to be between the strain-sensing element and the metal body, the groove causing the strain induced in the silicon chip by movement of the diaphragm to be further concentrated at the strain-sensing element of the silicon chip. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A sensing structure comprising:
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a metal body having a diaphragm, the metal body having an edge formed by an abrupt change in thickness of the metal body in a direction normal to the diaphragm, the edge defining a boundary of the diaphragm; a silicon chip secured to the metal diaphragm, the silicon chip comprising a strain-sensing element aligned with the edge of the body in the direction normal to the diaphragm, whereby movement of the diaphragm induces strain in the silicon chip that is concentrated at the strain-sensing element of the silicon chip, the silicon chip having a surface facing the metal body, the silicon chip having a plurality of recesses in the surface. - View Dependent Claims (9, 10)
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11. A pressure sensor assembly comprising:
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a stainless steel body comprising a diaphragm, a rim surrounding the diaphragm, a boss centrally located on the diaphragm, a first edge formed by an abrupt change in thickness of the metal body in a direction normal to the diaphragm between the diaphragm and the rim, and a second edge formed by an abrupt change in thickness of the metal body in the direction normal to the diaphragm between the diaphragm and the boss; a single-crystal silicon chip secured to the metal diaphragm, the silicon chip comprising a plurality of piezoresistive strain-sensing elements, each of the strain-sensing elements being aligned over at least one of the first and second edges of the body in the direction normal to the diaphragm, whereby movement of the diaphragm induces strain in the silicon chip that is concentrated at the strain-sensing elements of the silicon chip. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification