Patent ID: 8581578
Filing Date: 2013-11-12
Classification: G01R,G07D

Abstract:
1. A magnetic pattern detection device for use with a medium having at least one magnetic pattern of a plurality of types of magnetic patterns whose residual magnetic flux density and permeability are different on a basis of both of a level of residual magnetic flux density and a level of permeability, the magnetic pattern detection device comprising: a common sensor part structured to detect presence/absence of each of the plurality of types of magnetic patterns; and a signal processing section structured to extract a first signal corresponding to the level of the residual magnetic flux density and a second signal corresponding to the level of the permeability from a signal outputted from the sensor part; wherein the common sensor part comprises: wherein the magnetic flux detecting part comprises a magnetic sensor element which includes a sensor core, a bias exciting coil which is wound around the sensor core and structured to generate the bias magnetic field, and a detection coil which is wound around the sensor core, and the magnetic sensor element is accommodated within a magnetic shield case; wherein the magnetic field application part comprises a permanent magnet which is disposed on a front side in a feeding direction of the medium with respect to the magnetic sensor element accommodated within the magnetic shield case; and wherein the medium applied with a magnetic field of the permanent magnet is passed through the magnetic flux detecting part and, in the magnetic flux detecting part, the bias magnetic field is applied to the medium by the bias exciting coil and the magnetic flux is detected by the detection coil and thereby the first signal corresponding to the level of the residual magnetic flux density and the second signal corresponding to the level of the permeability are extracted from a signal outputted from the detection coil.