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US 5,844,287 AGranted
Monolithic sensor of fingerprints
AssigneesFrance Telecom, La Poste
InventorsSalman Abou Hassan, Marie-Josephe Revillet
Life of this patent
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AssigneesFrance Telecom, La Poste
InventorsSalman Abou Hassan, Marie-Josephe Revillet
Estimating the term…
An electronic fingerprint sensor works by the detection of pressure, the ridge lines of the finger exerting a greater pressure than the valleys. The sensor has a matrix of pressure microsensors and electronic control and signal-processing circuits. It is made in an entirely monolithic form, according to techniques for the making of electronic circuits (deposition of thin layers, photo-etching, doping and thermal processing), both for the pressure detection part and for the signal-processing and control part. The matrix-type pressure sensor uses either piezoelectric resistors lying on an insulator layer stretched above a cavity or a variable capacitor or a microcontactor.
A fingerprint sensor comprising a matrix of pressure microsensors sensitive to the pattern of a fingerprint, the matrix of pressure microsensors being implemented in an integrated circuit, each pressure microsensor of the matrix including a deformable diaphragm which closes off a cavity, the cavity being disposed between the diaphragm and a substrate of the integrated circuit, the diaphragm being formed of an insulator material, and the diaphragm having disposed thereon a conductive element of the microsensor which deforms under the effect of a pressure applied to the diaphragm.
A fingerprint sensor comprising:
A fingerprint sensor comprising:
A fingerprint sensor comprising:
Dependencies are inferred from the claim text.