Electronic imager using an impedance sensor grid array mounted on or about a switch and method of making

摘要

An novel impedance sensor for use together with a switch 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.

主权项

1. An impedance sensor, comprising:
a plurality of substantially parallel drive lines configured to transmit a signal to a proximally located object; 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 drive lines on a different layer by a substantially incompressible dielectric located between the drive lines and pickup lines to form a sensing area having a two dimensional array of intrinsic electrode pairs that are impedance sensitive to detect ridge and valley features of a finger proximally located with respect to at least a portion of the sensing area; a circuit located outside the sensing area and configured to:
operate in a first security mode by sequentially activating individual ones of all of the substantially parallel drive lines, grounding drive lines that are adjacent to the activated drive line, and detecting one or more signals on one or more of the plurality of substantially parallel pickup lines, andoperate in a second security mode by sequentially activating only every other one of the plurality of substantially parallel drive lines, grounding drive lines that are adjacent to the activated drive line, and detecting a signal on only every other one of the plurality of substantially parallel pickup lines; and determine ridge and valley features of the proximally located finger based on the detected one or more signals.