Position detecting device, electromagnetic resonance stylus, and position detecting system

An electromagnetic resonance stylus comprising:

• a resonant circuit including a coil and a capacitor;
• a switch element connected parallel to the capacitor;
• and
• a processing circuit which, in operation, transmits data to a position detecting circuit by performing on/off control on the switch element according to the data to be transmitted to the position detecting circuit,
• wherein the position detecting circuit is coupled to a plurality of first loop coils arrayed in a first direction and a plurality of second loop coils arrayed in a second direction perpendicular to the first direction, and
• wherein the position detecting circuit, in operation, derives a position of the electromagnetic resonance stylus using a current calculated by subtracting, from one of a plurality of induced of currents detected in one of a plurality of second loop coils that is positioned at a first end in the second direction among the second loop coils, one of a plurality of currents detected in one of the second loop coils that is positioned at a second end in the second direction among the second loop coils, as the one of a plurality of induced currents detected in the one of the second loop coils that is positioned at the first end in the second direction among the second loop coils.

A position detecting system comprising:

• an electromagnetic resonance stylus;
• and
• a position detecting device,
• wherein the electromagnetic resonance stylus includes:
• a resonant circuit including a coil and a capacitor,
• a switch element connected parallel to the capacitor, and
• a processing circuit which, in operation, transmits data to the position detecting circuit by performing on/off control on the switch element according to the data to be transmitted to the position detecting circuit,
• wherein the position detecting device includes:
• a plurality of first loop coils arrayed in a first direction,
• a plurality of second loop coils arrayed in a second direction perpendicular to the first direction, and
• a sensor controller which, in operation, detects induced currents respectively in the second loop coils while energizing one of the first loop coils, and
• wherein the sensor controller, in operation, derives a position of the electromagnetic resonance stylus using a current calculated by subtracting, from one of a plurality of induced currents detected in one of the second loop coils that is positioned at a first end in the second direction among the second loop coils, one of the induced currents detected in one of the second loop coils that is positioned at a second end in the second direction among the second loop coils, as the one of the induced currents detected in the one of the second loop coils that is positioned at the first end in the second direction among the second loop coils.