초록 ▼

A fingerprint sensor includes an array of fingerprint sensing elements; analog-to-digital (A/D) converters having a controllable range; a scanner to perform sequential A/D conversions of predetermined ones of the array of fingerprint sensing elements; and a range determining and setting circuit for

A fingerprint sensor includes an array of fingerprint sensing elements; analog-to-digital (A/D) converters having a controllable range; a scanner to perform sequential A/D conversions of predetermined ones of the array of fingerprint sensing elements; and a range determining and setting circuit for controlling the range of the A/D converters based upon prior A/D conversions to thereby provide enhanced conversion resolution. A plurality of A/D converters are preferably used for simultaneously converting analog signals from a corresponding plurality of fingerprint sensing elements. The A/D converters may include at least one reference voltage input for permitting setting of first and second points of the range. The range scale determining and setting circuit may generate a histogram based upon prior A/D conversions. In addition, the range scale determining and setting circuit may set a default range for initial ones of the fingerprint sensing elements.

대표청구항 ▼

[ That which is claimed is:] [1.]1. A fingerprint sensor to enhance conversion resolution of ridges and valleys of sensed fingerprints, the fingerprint sensor comprising:an array of fingerprint sensing elements, each element comprising an electric field sensing electrode and an amplifier associated

[ That which is claimed is:] [1.]1. A fingerprint sensor to enhance conversion resolution of ridges and valleys of sensed fingerprints, the fingerprint sensor comprising:an array of fingerprint sensing elements, each element comprising an electric field sensing electrode and an amplifier associated therewith;analog-to-digital (A/D) conversion means having a controllable range and for converting analog signals from said array of fingerprint sensing elements to digital signals based upon the range;scanning means responsive to said array of fingerprint sensing elements and positioned in communication with said A/D conversion means for operating said A/D conversion means and said array of fingerprint sensing elements to perform sequential A/D conversions of predetermined ones of said array of fingerprint sensing elements; andrange determining and setting means responsive to each said A/D conversion means for controlling the range of said A/D conversion means based upon a plurality of the sequential A/D conversions performed by said A/D conversion means to thereby provide enhanced conversion resolution of ridges and valleys of sensed fingerprints.