Patent ID: 8217645

Claim:
A position detecting system comprising: a detected object disposed in a detection space; and an external device disposed outside the detection space, wherein the detected object includes a resonant circuit that generates a resonant magnetic field according to a driving magnetic field formed in the detection space, and the external device includes at least two drive coils that form the driving magnetic field in the detection space; at least two drive-signal input units that input a drive signal for forming the driving magnetic field to the drive coils, respectively; at least one sense coil that detects a magnetic field formed in the detection space; a signal adjustment unit that adjusts a phase or an amplitude of the drive signal input to each of the drive coils by the drive-signal input units, by using an evaluation function for evaluating the phase or the amplitude of the drive signal, based on an intensity of the magnetic field detected by the sense coil; and a position deriving unit that derives a position of the detected object based on a magnetic field detected by the sense coil, wherein the evaluation function derives a solution by adding or multiplying a weight set according to a positional relation between each drive coil and each sense coil to or by an intensity of a magnetic field detected by the sense coils.