Thin-film magnetic field sensor

A thin-film magnetic field sensor comprising:

• a magnetic field sensor element including soft magnetic thin-films, which are separated by a gap having a predetermined gap length, and each have a predetermined film thickness and a predetermined width at a portion in contact with the gap, a giant-magneto-resistant thin-film formed to fill the gap, and electrical terminals respectively and electrically connected to the two separated soft magnetic thin-films;
• and
• a magnetic field generator configured to apply a bias magnetic field to the magnetic field sensor element for arbitrarily shifting a magnetic field zero point in an electrical resistance change curve,
• wherein the magnetic field sensor element detects a degree and polarity of an external magnetic field together from the electrical terminals, using the bias magnetic field.

A thin-film magnetic field sensor comprising:

• a magnetic field sensor element including soft magnetic thin-films, which are separated by a gap having a predetermined gap length, and each have a predetermined film thickness and a predetermined width at a portion in contact with the gap, a giant-magneto-resistant thin-film formed to fill the gap, and electrical terminals respectively and electrically connected to the two separated soft magnetic thin-films;
• a coil wound around the soft magnetic thin-films and the giant-magneto-resistant thin-film of the magnetic field sensor element;
• and
• means for supplying a current to the coil,
• wherein current values caused to flow in the coil include a current value which substantially saturates magnetization of the soft magnetic thin-films.

A thin-film magnetic field sensor comprising:

• a magnetic field sensor element including soft magnetic thin-films, which are separated by a gap having a predetermined gap length, and each have a predetermined film thickness and a predetermined width at a portion in contact with the gap, a giant-magneto-resistant thin-film formed to fill the gap, and electrical terminals respectively and electrically connected to the two separated soft magnetic thin-films;
• a coil wound around the soft magnetic thin-films and the giant-magneto-resistant thin-film of the magnetic field sensor element;
• and
• means for supplying a current to the coil,
• wherein an absolute value and polarity of the intensity of a magnetic bold around the magnetic field sensor are determined by performing the following operations in order:
• (1) supplying electric current to the coil, while setting the electric current to be a positive current which substantially saturates magnetization of the soft magnetic thin-films;
• (2) reducing a value of the electric current to supply a predetermined positive current within a range which does not provide saturation, and measuring a resistance value Rpp between the terminals at this time;
• (3) changing the electric current from the predetermined positive current to a predetermined negative current, and measuring a resistance value Rpm between the terminals at this time;
• (4) supplying electric current to the coil, while setting the electric current to be a negative current which substantially saturates magnetization of the soft magnetic thin-films;
• (5) reducing the value of the electric current to supply a predetermined negative current within a range which does not provide saturation, and measuring a resistance value Rmm between the terminals at this time;
• (6) changing the electric current from the predetermined negative current to a predetermined positive current, and measuring a resistance value Rmp between the terminals at this time;
• and
• (7) calculating ((Rpm+Rmm)/2−(Rpp+Rmp)/2), based on the resistance values thus obtained.

A thin-film magnetic field sensor comprising a bridge circuit and a coil wound around the bridge circuit, the bridge circuit comprising:

• a first sensor-basic element including soft magnetic thin-films, which are separated by a gap having a predetermined gap length, and each having a predetermined film thickness and a predetermined width at a portion in contact with the gap, a giant-magneto-resistant thin-film formed to fill the gap between the soft magnetic thin-films, and first and second terminals respectively and electrically connected to the two separated soft magnetic thin-films;
• a second sensor-basic element including soft magnetic thin-films, which are separated by a gap having a predetermined gap length, and each having a predetermined film thickness and a predetermined width at a portion in contact with the gap, a giant-magneto-resistant thin-film formed to fill the gap between the soft magnetic thin-films, and first and second terminals respectively and electrically connected to the two separated soft magnetic thin-films;
• a first intermediate element including a first conductor electrically connected to the first terminal of the first sensor-basic element, a second conductor electrically connected to the first terminal of the second sensor-basic element, and a giant-magneto-resistant thin-film disposed between and in contact with the first and second conductors;
• and
• a second intermediate element including a first conductor electrically connected to the second terminal of the first sensor-basic element, a second conductor electrically connected to the second terminal of the second sensor-basic element, and a giant-magneto-resistant thin-film disposed between and in contact with the first and second conductors.