Sensor apparatus, integrated circuit, and method of detecting indicator using linear electrodes and detection coils

An integrated circuit connected to a linear electrode group extended in parallel and a detection coil group crossing the linear electrode group, the integrated circuit comprising:

• at least one processor;
• and
• at least one memory storing instructions that, when executed by the at least one processor, cause the integrated circuit to:
• detect an indicator;
• sequentially send alternating magnetic fields from the linear electrode group,
• use the detection coil group to detect an alternating magnetic field generated by the indicator according to the alternating magnetic fields;
• determine a linear electrode set including part of the linear electrode group based on a result of detecting the alternating magnetic field generated by the indicator;
• execute a process of sending alternating magnetic fields from at least part of the linear electrode set for a plurality of times, the process including selecting a predetermined number of linear electrodes from a plurality of linear electrodes included in the linear electrode set and supplying a first alternating current to half of the predetermined number of linear electrodes and supplying a second alternating current different from the first alternating current to the predetermined number of linear electrodes other than the half of the predetermined number of linear electrodes at a same time, wherein the first alternating current and the second alternating current are generated to satisfy a relation that phases of time derivatives of the first alternating current and the second alternating current are opposite;
• use a plurality of result values detected by at least part of the detection coil group as a result of executing the process to derive a two-dimensional position of the indicator;
• and
• update the linear electrode set according to the two-dimensional position.

A method of detecting an indicator by using a linear electrode group extended in parallel and a detection coil group crossing the linear electrode group, the method comprising:

• sequentially sending alternating magnetic fields from the linear electrode group;
• using the detection coil group to detect an alternating magnetic field generated by the indicator according to the alternating magnetic fields;
• determining a linear electrode set including part of the linear electrode group based on a result of detecting the alternating magnetic field;
• executing a process of sending alternating magnetic fields from at least part of the linear electrode set for a plurality of times, the process including selecting a predetermined number of linear electrodes from a plurality of linear electrodes included in the linear electrode set and supplying a first alternating current to half of the predetermined number of linear electrodes and supplying a second alternating current different from the first alternating current to the predetermined number of linear electrodes other than the half of the predetermined number of linear electrodes at a same time, wherein the first alternating current and the second alternating current are generated to satisfy a relation that phases of time derivatives of the first alternating current and the second alternating current are opposite;
• using a plurality of result values detected by at least part of the detection coil group as a result of the executing the process to derive a two-dimensional position of the indicator;
• and
• updating the linear electrode set according to the two-dimensional position.