Patent ID: 7423629

Claim:
A position detection system comprising a position pointer including at least one coil, for pointing to a position, and a position detector for detecting the position pointed to by the position pointer by transmitting and receiving a signal to and from the position pointer by means of electromagnetic coupling, the position detector comprising: a plurality of transmission coils for transmitting a position pointer exciting signal to the position pointer; a plurality of sensor coils for receiving a position indicating signal transmitted from the position pointer in response to the position pointer exciting signal; signal transmission means for selecting one of the plurality of transmission coils in accordance with the position of the position pointer indicated by the position indicating signal and for driving the selected transmission coil so as to transmit the position pointer exciting signal to the position pointer; reception means for selecting the plurality of sensor coils one by one and receiving the position indicating signal transmitted from the position pointer; and position detection means for detecting the position pointed to by the position pointer in accordance with the position indicating signal received by the reception means, wherein, depending on a relative spatial relationship between the selected transmission coil and the position of the position pointer detected by the position detection means, the signal transmission means drives the selected transmission coil such that the phase of the position pointer exciting signal supplied to the position pointer is maintained without being inverted.