To provide a geomagnetic direction sensor having practical sensitivity, allowing a compact structure as well as a low cost to be easily realized, and further having high sensing accuracy by applying a constitution that magnetic substance cores are laid in the circumferential direction at a prescribed gap, and an exciting coil capable of generating bias magnetic field upon receipt of bias current is wound around a ferromagnetic substance.
A chip sensor 1 is formed out of ferrite or the like and a pair of ferromagnetic cores K1 and K2 bent in such a state as having both edges directed in the same direction are abutted on each other, thereby forming the chip sensor 1 into a rectangular shape. The cores K1 and K2 respectively having gaps G1 and G2, and G3 and G4 made of glass material, and the gaps G1 to G4 are laid at four corners at 90-degree intervals. Also, MR elements M1 to M4 are formed on the gaps G1 to G4 respectively. In addition, output from the element M1 and M2, and M3 and M4 is generated in in X- and Y-axis directions respectively via operation amplifiers. In this case, the resistance values of the elements M1 and M2 change, depending on the intensity of magnetic field, and the elements M1 and M2 have a high function of sensing weak magnetic field.
FUJITA MASAYOSHI
ABE MORIAKI
