Patent ID: 8421445

Claim:
A position detecting system comprising: a detected object disposed in a detection space to generate an induced magnetic field in response to a driving magnetic field generated in the detection space; one or more magnetic field generating coils that generate the driving magnetic field in the detection space; a magnetic field detecting coil that detects a synthetic magnetic field of the driving magnetic field and the induced magnetic field generated by the detected object in response to the driving magnetic field; a current detecting unit that detects a driving current flowing through the magnetic field generating coil in synchronization with magnetic field detection by the magnetic field detecting coil; a position information calculating unit that calculates a position and a direction of the detected object based on a detection value of the synthetic magnetic field detected by the magnetic field detecting coil and a detection value of the driving current detected by the current detecting unit; and a calibration calculating unit that calculates a phase of a driving magnetic field component which corresponds to the driving magnetic field at the detection value of the synthetic magnetic field detected by the magnetic field detecting coil, based on the detection value of the driving current detected by the current detecting unit, wherein the position information calculating unit obtains a component having a phase difference approximately orthogonal to the phase of the driving magnetic field component calculated by the calibration calculating unit, from the synthetic magnetic field detected by the magnetic field detecting coil, and calculates the position and direction of the detected object based on the obtained component.