Simultaneous detection of in-plane and out-of-plane position displacement with capacitive sensors
First Claim
1. An apparatus for simultaneously detecting in-plane and out-of-plane position displacement of a capacitive sensor in a data storage device, comprising:
- a capacitive sensor having a first electrode connected to a first AC supply voltage operating at a first frequency;
a second electrode connected to a second AC supply voltage operating at the first frequency, wherein each of the first and second supply voltages includes an in-phase component and a quadrature component, 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 AC 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 AC 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 in the data storage device.
5 Assignments
0 Petitions
Accused Products
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.
31 Citations
18 Claims
-
1. An apparatus for simultaneously detecting in-plane and out-of-plane position displacement of a capacitive sensor in a data storage device, comprising:
-
a capacitive sensor having a first electrode connected to a first AC supply voltage operating at a first frequency; a second electrode connected to a second AC supply voltage operating at the first frequency, wherein each of the first and second supply voltages includes an in-phase component and a quadrature component, 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 AC 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 AC 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 in the data storage device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. An apparatus for simultaneously detecting in-plane and out-of-plane position displacement of capacitive sensors in a data storage device, comprising:
-
a capacitive sensor having a first electrode connected to a first AC 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 AC supply voltage having a first component at the first frequency and the 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 AC 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 AC 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 in the data storage device. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
-
-
17. A method for simultaneously detecting in-plane and out-of-plane position displacement of a capacitive sensor in a data storage device, comprising:
-
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 AC 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 in the data storage device; combining the sense voltage with a second AC 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 in the data storage device. - View Dependent Claims (18)
-
Specification