Low cost high-pressure sensor
First Claim
1. A pressure sensing apparatus which comprises:
- a) a pressure port having an upper surface and a base portion;
b) an elastically deformable pressure-sensitive diaphragm assembly having upper and lower surfaces and a central pressure-sensitive diaphragm;
the lower surface of the diaphragm assembly being attached onto the upper surface of the pressure port;
c) a substantially planar disc having upper and lower surfaces;
the lower surface of the disc being bonded to the upper surface of the diaphragm assembly via a layer of a bonding material;
d) a ceramic material layer on the upper surface of the disc; and
e) a plurality of piezoresistive elements on the ceramic material layer.
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Accused Products
Abstract
A pressure sensing apparatus including a thin disc of a metal having a ceramic material layer and piezoresistive elements formed thereon. A surface of the disc is bonded to a diaphragm assembly on a pressure port base constructed of a low cost metal. The bonding process is performed at low temperatures, (<700° C.), so that the diaphragm assembly and pressure port do not require high temperature corrosion resistance, and can thus be formed of less expensive materials. The inventive apparatus provides a lower cost alternative to conventional high pressure sensors since less material is used, less expensive materials are used, and fabrication is less complex. The inventive apparatus is also more reliable and exhibits greater thermal stability than conventional high pressure sensors.
35 Citations
28 Claims
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1. A pressure sensing apparatus which comprises:
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a) a pressure port having an upper surface and a base portion; b) an elastically deformable pressure-sensitive diaphragm assembly having upper and lower surfaces and a central pressure-sensitive diaphragm;
the lower surface of the diaphragm assembly being attached onto the upper surface of the pressure port;c) a substantially planar disc having upper and lower surfaces;
the lower surface of the disc being bonded to the upper surface of the diaphragm assembly via a layer of a bonding material;d) a ceramic material layer on the upper surface of the disc; and e) a plurality of piezoresistive elements on the ceramic material layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for forming a pressure sensing apparatus which comprises:
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a) providing a substantially planar disc having upper and lower surfaces; b) forming a ceramic material layer on the upper surface of the disc; c) forming a plurality of piezoresistive elements on the ceramic material layer; d) providing a pressure port having an upper surface and a base portion; e) attaching a deformable pressure-sensitive diaphragm assembly, having upper and lower surfaces and a central pressure-sensitive diaphragm, onto the pressure port such that the lower surface of the diaphragm assembly is attached onto the upper surface of the pressure port; and f) bonding the lower surface of the disc to the upper surface of the diaphragm assembly. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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28. A method for sensing pressure, which comprises:
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I) providing a pressure sensing apparatus comprising; a) a pressure port having an upper surface and a base portion; b) an elastically deformable pressure-sensitive diaphragm assembly having upper and lower surfaces and a central pressure-sensitive diaphragm;
the lower surface of the diaphragm assembly being attached onto the upper surface of the pressure port;c) a substantially planar disc having upper and lower surfaces;
the lower surface of the disc being bonded to the upper surface of the diaphragm assembly via a layer of a bonding material;d) a ceramic material layer on the upper surface of the disc; and e) a plurality of piezoresistive elements on the ceramic material layer; II) placing the pressure sensing apparatus into a pressurized environment, thereby causing the diaphragm to deform in response to changes in pressure; III) detecting any changes in pressure of the pressurized environment via the piezoresistive elements; and IV) analyzing the pressure of the pressurized environment by observing changes in the piezoresistive elements.
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Specification