MAGNETIC HEAD FOR BANKNOTE DETECTION

摘要

A magnetic currency verification head may include a magnetoresistive sensor chip, and a magnetic bias unit disposed on the side of the magnetoresistive sensor chip away from the detection surface of the magnetic currency verification head, and separated from the magnetoresistive sensor chip; the magnetoresistive sensor chip comprises a gradiometric bridge circuit that includes magnetic sensor elements; the sensitive direction of the magnetic sensor elements is parallel to the detection surface of the magnetic currency verification head; and the magnetic bias unit has a recessed magnetic structure configured such that the magnetic field generated by the magnetic bias unit only has a small magnetic field component in the direction parallel to the detection surface, thereby enabling the magnetic sensor elements to operate in their linear range. As a result, the magnetic currency verification head has high sensitivity and signal-to-noise ratio.

主权项

1. A magnetic currency verification head comprising:
a magnetoresistive sensor chip and a separate magnetic bias unit disposed on the side of the magnetoresistive sensor chip away from the magnetic currency verification head detection surface, wherein the magnetoresistive sensor chip comprises a gradiometric bridge circuit that includes magnetic sensor elements with a sensitive direction parallel to a magnetic currency verification head detection surface; the magnetic bias unit has a recessed magnetic structure arranged such that the magnetic bias field generated by the magnetic bias unit in the direction parallel to the magnetic currency verification head detection surface is small thereby enabling the magnetic sensor elements to operate in their linear range.