Patent ID: 6154580
Filing Date: 2000-11-28
Classification: G06K

Abstract:
A fingerprint sensor for converting a fingerprint information into an electric signal, comprising;a plurality of tactile sensors, each havinga field-effect transistor (FET) including a source region, a drain region, a channel region between said source and drain regions, and an insulating film on said source, drain and channel regions,an elastic body of an insulating material on said insulating film above said channel region, anda member of an electrically conductive material on said elastic body;a constant current source transistor (CCST) connected, as a source of constant current, to each of at least some of said tactile sensors to form a source follower circuit;a common output terminal for tactile sensors;a first switching element connected between the source region of each tactile sensor, to which said transistor is connected, and said common output terminal for tactile sensors;a source of electric power;a second switching element connected between said source of electric power and said tactile sensor in each of said source follower circuits.