Capacitive pressure sensor with reduced parasitic capacitance
First Claim
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1. A capacitive pressure sensor, comprising:
- an upper housing comprising an upper pressure port;
a lower housing comprising a lower pressure port, said lower housing being coupled to an active shield;
a conductive diaphragm positioned between the upper and lower housing;
an insulator, positioned in the pressure sensor to insulate the conductive diaphragm from the lower housing;
a sensing electrode positioned in the lower housing, wherein the sensing electrode extends laterally across at least a portion of the conductive diaphragm and is separated from the conductive diaphragm by a predetermined distance, and wherein the conductive diaphragm is electrically coupled to the upper housing.
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Abstract
System, apparatus and method for capacitive sensing, where a sensor includes an upper and lower housing, each respectively equipped with upper and lower pressure ports. The lower housing is electrically coupled to an active shield. An insulating material is provided on or near a conductive diaphragm for insulating the conductive diaphragm from the lower housing. The insulating material may be an insulator or a dielectric material, where a sensing electrode is positioned such that the sensing electrode extends laterally across at least a portion of the insulating material, and is separated from the insulating material by a predetermined distance to form an air gap.
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Citations
16 Claims
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1. A capacitive pressure sensor, comprising:
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an upper housing comprising an upper pressure port; a lower housing comprising a lower pressure port, said lower housing being coupled to an active shield; a conductive diaphragm positioned between the upper and lower housing; an insulator, positioned in the pressure sensor to insulate the conductive diaphragm from the lower housing; a sensing electrode positioned in the lower housing, wherein the sensing electrode extends laterally across at least a portion of the conductive diaphragm and is separated from the conductive diaphragm by a predetermined distance, and wherein the conductive diaphragm is electrically coupled to the upper housing. - View Dependent Claims (2, 3, 4, 5)
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6. A capacitive pressure sensor, comprising:
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an upper housing comprising an upper pressure port; a lower housing comprising a lower pressure port, said lower housing being coupled to an active shield; a conductive diaphragm positioned between the upper and lower housing; a dielectric material coupled to the conductive diaphragm for insulating the conductive diaphragm from the lower housing; and a sensing electrode positioned in the lower housing, wherein the sensing electrode extends laterally across at least a portion of the dielectric material and is separated from the dielectric material by a predetermined distance to form an air gap, and wherein the conductive diaphragm is electrically coupled to the upper housing. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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13. A method of forming a capacitive pressure sensor, comprising the steps of:
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providing an upper housing comprising an upper pressure port; providing a lower housing comprising a lower pressure port, said lower housing being coupled to an active shield; positioning a conductive diaphragm between the upper and lower housing; coupling an insulating material to the conductive diaphragm for insulating the conductive diaphragm from the lower housing, said insulating material comprising one of (i) and insulator and (ii) a dielectric material; electrically coupling the conductive diaphragm to the upper housing; and positioning a sensing electrode in the lower housing, such that the sensing electrode extends laterally across at least a portion of the insulating material, and is separated from the insulating material by a predetermined distance to form an air gap. - View Dependent Claims (14, 15, 16)
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Specification