Method and apparatus for measuring structures in a fingerprint
First Claim
1. An apparatus for sensing a fingerprint comprising:
- an essentially one-dimensional sensor array including a plurality of sensors and associated circuitry constructed and arranged to generate a signal at each of a plurality of different portions of a fingerprint surface at predetermined intervals of time as the fingerprint surface is moved relative to said sensor array in a direction that is generally perpendicular to said sensor array, each signal corresponding to surface features of the associated portion of the fingerprint surface; and
at least one external electrode positioned adjacent said sensor array and coupled to said circuitry, said circuitry being adapted to apply a voltage to said external electrode relative to said sensors.
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Accused Products
Abstract
A plurality of images of portions of a fingerprint surface is generated by measuring structural features the portions of the surface with a sensor array as the surface is moved relative to the array. A two-dimensional image of the fingerprint surface is constructed from a portion of the plurality of images. In one embodiment, a varying voltage is applied to a finger positioned over an exciting electrode and a capacitive sensor array, and the capacitance or impedance through the finger is measured between the electrode and the array to detect variations in capacitance or impedance caused by variations in the structural features of the fingerprint surface. In one embodiment, the speed of the fingerprint surface relative to the sensor array is determined by sensing features of the fingerprint surface at two spaced-apart sensing elements and determining the speed from the distance between the sensing elements and the time lapse between passage of identical features of the fingerprint surface from one of the sensing elements to the other.
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Citations
13 Claims
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1. An apparatus for sensing a fingerprint comprising:
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an essentially one-dimensional sensor array including a plurality of sensors and associated circuitry constructed and arranged to generate a signal at each of a plurality of different portions of a fingerprint surface at predetermined intervals of time as the fingerprint surface is moved relative to said sensor array in a direction that is generally perpendicular to said sensor array, each signal corresponding to surface features of the associated portion of the fingerprint surface; and
at least one external electrode positioned adjacent said sensor array and coupled to said circuitry, said circuitry being adapted to apply a voltage to said external electrode relative to said sensors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification