Low cost capacitive accelerometer
First Claim
1. A semiconductor acceleration transducer comprising:
- at least one first substrate means having an electrically conductive portion for forming a first capacitor plate; and
an acceleration-responsive semiconductor means coupled to said substrate means and spaced adjacent said electrically conductive portion for forming a second capacitor plate and being movable in response to acceleration to cause a change in capacitance between said first and second plates, said semiconductor means comprising a semiconductor element including a central post portion attached to said first substrate means, an elastic diaphragm portion circumferentially extending from said post portion and an acceleration-responsive mass ring portion circumferentially extending from said diaphragm portion.
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Accused Products
Abstract
A capacitive transducer is disclosed which provides a measurement of acceleration. The transducer includes a semiconductor element having a mass ring suspended from an elastic diaphragm which is retained by a support. The mass ring is formed to have opposed parallel planar surfaces, each of which are spaced adjacent a metal layer deposited on a glass substrate to form a capacitive circuit. The metal layers are configured in the shape as the flat surface of the mass ring and are coupled to provide an electrical output. The semiconductor element forms a common capacitor plate disposed between the two capacitor plates formed by the metal layers. Movement of the mass ring in response to acceleration causes a change in the spacing between the mass ring and metal layers thereby changing the capacitance and providing a measure of acceleration.
52 Citations
12 Claims
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1. A semiconductor acceleration transducer comprising:
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at least one first substrate means having an electrically conductive portion for forming a first capacitor plate; and an acceleration-responsive semiconductor means coupled to said substrate means and spaced adjacent said electrically conductive portion for forming a second capacitor plate and being movable in response to acceleration to cause a change in capacitance between said first and second plates, said semiconductor means comprising a semiconductor element including a central post portion attached to said first substrate means, an elastic diaphragm portion circumferentially extending from said post portion and an acceleration-responsive mass ring portion circumferentially extending from said diaphragm portion. - View Dependent Claims (2)
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3. A semiconductor acceleration transducer comprising:
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a first electrically insulating substrate having an electrically conductive surface forming a first capacitor plate; a second electrically insulating substrate having an electrically conductive surface forming a second capacitor plate, said first and second substrates being positioned adjacent one another to position their respective capacitor plates in opposed, spaced relationship; and an acceleration-responsive semiconductor element attached to and positioned between said first and second substrates and including a post portion attached to said first and second substrates, a flexible semiconductor diaphragm extending from said post portion and a mass ring portion extending from said diaphragm portion between said first and second substrates and positioned in spaced relation to said electrically conductive surfaces to form a common capacitor plate therebetween. - View Dependent Claims (4, 5, 6)
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7. A semiconductor accelerometer transducer comprising:
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a first electrically insulating substrate having opposed parallel planar surfaces; an electrically conductive layer disposed on one of said surfaces of said first substrate forming a first capacitor plate; electrically conductive means attached to said first capacitor plate for forming an electrical terminal which provides an electrically conductive path to said first capacitor plate; an acceleration-responsive semiconductor element including a central mounting post portion having opposed parallel planar surfaces, one of which is centrally attached to said one surface of said first substrate, a flexible diaphragm portion extending about the periphery of said mounting post portion, and a mass ring portion having opposed parallel planar surfaces and extending about the periphery of said diaphragm portion, said mass ring portion being retained by said post portion and diaphragm portion so that one of the planar surfaces is spaced from the conductive layer forming said first capacitor plate; a second electrically insulating substrate having opposed parallel planar surfaces one of which is attached to the mounting post portion of said semiconductor element to position one of its surfaces in opposed parallel relation to the other surface of said mass ring portion; an electrically conductive layer disposed on said one surface of said second substrate to form a second capacitor plate positioned in opposed spaced parallel relation to said other surface of said mass ring portion; and electrically conductive means attached to said second capacitor plate for forming an electrical terminal which provides an electrically conductive path to said second capacitor plate. - View Dependent Claims (8, 9, 10, 11)
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12. A semiconductor acceleration transducer comprising:
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at least one first substrate means having an electrically conductive portion for forming a first capacitor plate; and an acceleration-responsive semiconductor means coupled to said substrate means and spaced adjacent said electrically conductive portion for forming a second capacitor plate and being movable in response to acceleration to cause a change in capacitance between said first and second plates, said semiconductor means comprising an integral structure formed from a semiconductor wafer including a central post portion attached to said first substrate means, an elastic diaphragm portion circumferentially extending from said post portion, and an acceleration-responsive mass ring portion circumferentially extending from said diaphragm portion.
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Specification