Electronic Imager Using an Impedance Sensor Grid Array and Method of Making

• US 20130193988A1
• Filed: 03/13/2013
• Published: 08/01/2013
• Est. Priority Date: 01/15/2010
• Status: Active Grant

• Current Assignee: IDEX Biometrics ASA
• Original Assignee: Picofield Technologies, Inc.
• Inventors: Benkley, Fred G. III
• Granted Patent: US 9,600,704 B2
• Time in Patent Office: Days
• US Class Current: 324/658
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing

Abstract

An novel impedance sensor is provided having a plurality of substantially parallel drive lines configured to transmit a signal into a surface of a proximally located object, and also a plurality of substantially parallel pickup lines oriented substantially perpendicular to the drive lines and separated from the pickup lines by a dielectric to form intrinsic electrode pairs that are impedance sensitive at each of the drive and pickup crossover locations.

Claims

1. An fingerprint impedance sensor, comprising:

a plurality of substantially parallel drive lines configured to transmit a signal to a proximally located finger; and

a plurality of substantially parallel pickup lines configured to receive a resultant signal and oriented substantially perpendicular to the drive lines and physically separated from the pickup lines on a different layer by a substantially incompressible dielectric located between the drive lines and pickup lines to form a two dimensional array of intrinsic electrode pairs that are impedance sensitive to detect ridge and valley features of a proximally located finger when driven by circuitry located outside the sensing area that is connected to each drive and pickup line of the array in order to activate one or more junctions formed at individual dive and pickup line crossovers where the circuitry includes a driver or drive multiplexor connected to each drive line, and buffer, switch or input multiplexor attached to each pickup line, and at least one differencing amplifier configured to receive inputs from the input buffers or input multiplexor

where a signal proportional to impedance about each drive line and pickup crossover location can be measured relative to a signal proportional to impedance about another drive line and pickup crossover location to distinguish impedance values between a fingerprint ridge and a fingerprint valley of the proximally located finger for purposes of acquiring a fingerprint image.