Stmicroelectronics Gmbh

Upek, Inc.

Frederic Raynal

Marco Sabatini

Arnaud Yves Lepert

Giovanni Gozzini

Bhusan Gupta

Vito Fabrizzio

A fingerprint sensor includes an array comprising a plurality of capacitive pixel cells. Each of the capacitive pixel cells includes a pair of metal plates and a reset transistor. The reset transistor includes a gate, a source connected to one of the metal plates and a drain connected to the other of the metal plates. A reset buffer generates a reset signal. A regenerator is associated with each reset transistor of each capacitive pixel cell. The regenerator regenerates the reset signal received from the reset buffer to eliminate injection gradient over the array.

Method of and system for compensating for injection gradient in a capacitive sensing circuit array

A structure and method for dissipating charges comprising an underlying dielectric layer disposed over capacitor plates of sensor circuitry, and a conductive path and passivation layers disposed over the underlying dielectric layer wherein the conductive pad forms an electrically conductive path over at least a portion of the plates and diffuses electrostatic charges at the surface of the integrated circuit.

Static charge dissipation pads for sensors

A narrow array capacitive semiconductor fingerprint detection system includes an array of capacitive sensing elements. The array has a first dimension about the width of a fingerprint and second dimension less than the length of a fingerprint. A scan control unit is coupled to scan the array at a scan rate determined by the speed of finger movement over the array. The scan control unit scans the array capture partial fingerprint images. Output logic is coupled to the array to assemble the captured fingerprint images into a complete image based upon the direction of finger movement over the array. A mouse device is positioned adjacent the array in the path of finger movement over the array. The mouse device is coupled to provide finger movement speed information to the scan control unit. The mouse device is also coupled to provide finger movement direction information to the output logic.

Narrow array capacitive fingerprint imager

A narrow array optical fingerprint detector that substantially eliminates over-sampling of the array measures the speed of a finger moving over the array and scans the array at a rate determined by the speed of movement of the finger. The fingerprint detector measures the speed of finger movement with a transparent cylinder rotatably mounted adjacent the array. The transparent cylinder is mounted to engage the finger and rotate as the finger is swept past the array. A light chopper is mounted for rotation with the cylinder. A photo-sensor is mounted adjacent the light chopper. The photo-sensor produces a signal in response to light being chopped by the light chopper. The photo-sensor is operably connected to scanning circuitry. Each time the scanning circuitry receives a signal from the photo-sensor, the scanning circuitry scans the array.

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Berkeley, CA, United States of America

Frederic Raynal