Position detection method, position detector, and integrated circuit

A position detecting method in a position detector, the position detector including a first sensor coil group including a plurality of conducting wires having a plurality of electrodes arranged in parallel with each other in a first direction and a second sensor coil group including a plurality of conducting wires having a plurality of electrodes arranged in parallel with each other in a second direction intersecting the first direction, the position detecting method comprising:

• a first step of the position detector generating an alternating magnetic field from the first sensor coil group;
• a second step of the position detector obtaining a level of a pen signal which a pen, having stored the alternating magnetic field, generates as a response alternating magnetic field, by using at least the second sensor coil group;
• a third step of the position detector deriving information regarding a position of the pen by using a two-dimensional distribution of the level of the pen signal at each of points of intersection of the plurality of electrodes of the first sensor coil group and the plurality of electrodes of the second sensor coil group;
• a fourth step of the position detector obtaining a first reference position, which corresponds to a first peak in the two-dimensional distribution and which is a position indicated by a pen tip of the pen;
• a fifth step of the position detector obtaining an upwardly displaced or downwardly displaced second reference position, which corresponds to a second peak in the two-dimensional distribution, the second peak being different from the first peak and having the same sign as the second peak;
• and
• a sixth step of the position detector deriving, on a basis of a direction of the second reference position with respect to the first reference position, a direction of an inclination of the pen on the sensor plane, which is an angle on the sensor plane formed by a projection of the pen on the sensor plane.