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US 2018/0136271 A1Published application
Capacitive sensor with self-test feature
AssigneeTouchsensor Technologies, LLC
InventorRandall Philipson
Life of this patent
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Abstract
A capacitive sensor includes sensor electrode structure and a controller operating the sensor. The sensor also includes test drive electrode structure or a reference capacitor, the controller operating the test drive electrode structure or the reference capacitor to test operability of the sensor.
Claims12
A capacitive sensor comprising:
- a first dielectric substrate having a first side and a second side;
- a sensor electrode structure having a first sensing electrode disposed on the first side of the dielectric substrate;
- and
- a controller coupled to the first sensing electrode, the controller configured to:
- selectively energize the first sensing electrode, selectively detect capacitance at the first sensing electrode, and deem the sensor to be actuated or not actuated based on the capacitance detected at the first sensing electrode;
- selectively simulate actuation of the sensor while the sensor is not actuated;
- and
- selectively simulate deactivation of the sensor while the sensor is actuated or while the controller is simulating actuation of the sensor.
5 more elements
A capacitive sensor comprising:
- a first dielectric substrate having a first side and a second side;
- a sensor electrode structure having a sense electrode disposed on the first side of the dielectric substrate and a drive electrode on the second side of the dielectric substrate, the drive electrode at least partially overlying and in registration with the sense electrode;
- a reference capacitor proximate the sense electrode, the reference capacitor having a first plate and a second plate;
- a first switch operable to selectively couple the second plate of the reference capacitor to ground or to a floating potential;
- a second switch operable to selectively couple the sense electrode to ground;
- and
- a controller coupled to the sense electrode and the drive electrode, the controller configured to:
- with the first switch configured to couple the second plate of the reference capacitor to the floating potential, and with the second switch not configured to couple the sense electrode to ground, operate the capacitive sensor by selectively energizing the drive electrode, selectively detect capacitance at the sense electrode, and deem the sensor to be actuated or not actuated based on the capacitance detected at the sense electrode;
- operate the reference capacitor by selectively energizing the first plate of the reference capacitor and selectively detecting the capacitance at the first plate of the reference capacitor;
- deem the sensor to actuate properly when, with the sensor not actuated, with the first switch configured to couple the second plate of the reference capacitor to the floating potential and the second switch configured to couple the sense electrode to ground, the controller deems the capacitance of the reference capacitor to differ by a first predetermined value from the capacitance of the reference capacitor when the switch is configured to couple the second plate of the reference capacitor to the floating potential;
- and
- deem the sensor to deactuate properly when, with the sensor actuated, the first switch configured to couple the second plate of the reference capacitor to ground, and the second switch configured to couple the sense electrode to ground, the controller deems the capacitance of the reference capacitor to differ by a second predetermined value from the capacitance of the reference capacitor when the switch is configured to couple the second plate of the reference capacitor to the floating potential.
9 more elements
Dependencies are inferred from the claim text.