Simultaneous Detection of In-Plane and Out-Of-Plane Position Displacement With Capacitive Sensors
First Claim
1. An apparatus comprising:
- a capacitive sensor having a first electrode connected to a first supply voltagea second electrode connected to a second supply voltage, and a third electrode;
a sensing circuit for producing a sense voltage in response to current flowing between the first electrode and the third electrode, and between the second electrode and the third electrode;
a first mixer for combining the sense voltage with a first reference voltage to produce a first signal representative of in-plane displacement of the first and second electrodes with respect to the third electrode of the capacitive sensor; and
a second mixer for combining the sense voltage with a second reference voltage to produce a second signal representative of out-of-plane displacement of the first and second electrodes with respect to the third electrode of the capacitive sensor.
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Abstract
An apparatus includes a first capacitive sensor connected to a first supply voltage, a second capacitive sensor connected to a second supply voltage, a sensing circuit for producing a sense voltage in response to current flowing in the first and second capacitive sensors, a first mixer for combining the sense voltage with a first reference voltage to produce a first signal representative of in-plane displacement between electrodes of the first and second capacitive sensors, and a second mixer for combining the sense voltage with a second reference voltage to produce a second signal representative of out-of-plane displacement between the electrodes of the first and second capacitive sensors.
30 Citations
20 Claims
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1. An apparatus comprising:
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a capacitive sensor having a first electrode connected to a first supply voltage a second electrode connected to a second supply voltage, and a third electrode; a sensing circuit for producing a sense voltage in response to current flowing between the first electrode and the third electrode, and between the second electrode and the third electrode; a first mixer for combining the sense voltage with a first reference voltage to produce a first signal representative of in-plane displacement of the first and second electrodes with respect to the third electrode of the capacitive sensor; and a second mixer for combining the sense voltage with a second reference voltage to produce a second signal representative of out-of-plane displacement of the first and second electrodes with respect to the third electrode of the capacitive sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An apparatus comprising:
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a capacitive sensor having a first electrode connected to a first supply voltage having a first component at a first frequency and a second component at a second frequency a second electrode connected to a second supply voltage having a first component at the first frequency and a second component at the second frequency, and a third electrode; a sensing circuit for producing a sense voltage in response to current flowing between the first electrode and the third electrode, and between the second electrode and the third electrode; a first mixer for combining the sense voltage with a first reference voltage to produce a first signal representative of in-plane displacement of the first and second electrodes with respect to the third electrode of the capacitive sensor; and a second mixer for combining the sense voltage with a second reference voltage to produce a second signal representative of out-of-plane displacement of the first and second electrodes with respect to the third electrode of the capacitive sensor. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A method comprising:
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connecting a first electrode of a capacitive sensor to a first supply voltage; connecting a second electrode of the capacitive sensor to a second supply voltage; producing a sense voltage in response to current flowing in the first and second electrodes and a third electrode of the capacitive sensor; combining the sense voltage with a first reference voltage to produce a first signal representative of in-plane displacement of the first and second electrodes with respect to the third electrode of the capacitive sensor; and combining the sense voltage with a second reference voltage to produce a second signal representative of out-of-plane displacement of the first and second electrodes with respect to the third electrode of the capacitive sensor. - View Dependent Claims (20)
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Specification