Sensor for measurement for wet and dry fingers
AssigneeIdex Asa
InventorsJon Nysæther, Knut Riisnæs, Ørjan G. Martinsen, Geir Mostad, Nicolai W. Christie, Rune Pedersen
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Abstract
A sensor device for performing measurements on an at least partially conductive surface includes a number of conductive structures at or directly below the sensor surface. The conductive structures consist of at least one stimulation or current sink electrode and a number of sensor elements coupled to interrogation electrodes in an electronic circuit for measuring impedance between the electrodes and the stimulation electrode. The sensor device also includes at least one additional clamping electrode positioned in the vicinity of the sensor elements and coupled to a chosen voltage.
Claims20
A fingerprint sensor device for performing measurements on an at least partially conductive surface, the sensor comprising a number of conductive structures at or directly below the sensor surface, said conductive structures consisting of at least one stimulation or current sink electrode and a number of sensor elements coupled to interrogation electrodes in an electronic circuit for measuring impedance between the electrodes and said at least one stimulus electrode, the sensor device also comprising at least one additional clamping electrode being positioned in the vicinity of said sensor elements and being coupled to a chosen AC or DC voltage being significantly different from the voltage of the stimulation or current sink electrode.
Dependencies are inferred from the claim text.