Position detecting device and position detecting method

A position detecting device including a plate-shaped sensor in which a plurality of electrodes that receive by electric field coupling an alternating current signal from a capacitive stylus pen that transmits the alternating current signal from a tip, the position detecting device detecting a position indicated by the stylus pen on one surface of the sensor, the position detecting device comprising:

• an electrode selection circuit that selects at least each one electrode from the plurality of electrodes provided in the sensor for connection to a positive terminal and selects at least each one electrode from the plurality of electrodes provided in the sensor for connection to a negative terminal;
• a differential amplifier that amplifies and outputs a differential signal indicating a difference between signals generated at the positive terminal and the negative terminal;
• a contact detector that detects whether the stylus pen is in contact with the one surface of the sensor;
• and
• a control unit that carries out control to cause the electrode selection circuit to select two adjacent electrodes among the plurality of electrodes provided in the sensor for connection to the positive terminal and the negative terminal when contact of the stylus pen with the one surface of the sensor is detected by the contact detector, and carries out control to cause the electrode selection circuit to select two electrodes separated from each other by a certain interval among the plurality of electrodes provided in the sensor for connection to the positive terminal and the negative terminal when contact of the stylus pen with the one surface of the sensor is not detected by the contact detector.

A position detecting device comprising:

• a sensor in which a plurality of electrodes is disposed in at least a first direction;
• a differential amplifier circuit that includes a first input terminal and a second input terminal and that outputs a differential signal based on signals supplied to the first input terminal and the second input terminal;
• and
• an electrode selection circuit that selects electrodes for connection to the first input terminal and the second input terminal of the differential amplifier circuit from the plurality of electrodes disposed in the sensor,
• wherein a position indicated by a stylus pen that generates an electric field based on electric field coupling between the stylus pen and the sensor is detected based on the differential signal output from the differential amplifier circuit, and
• wherein if the differential signal output from the differential amplifier circuit corresponding to a first electrode selection pattern set by the electrode selection circuit satisfies a set predetermined condition, a second electrode selection pattern different from the first electrode selection pattern is set by the electrode selection circuit to detect the position indicated by the stylus pen.

A position detecting method of a position detecting device including a sensor in which a plurality of electrodes is disposed in at least a first direction, a differential amplifier circuit that includes a first input terminal and a second input terminal and that outputs a differential signal based on signals supplied to the first input terminal and the second input terminal, and an electrode selection circuit that selects electrodes for connection to the first input terminal and the second input terminal of the differential amplifier circuit from the plurality of electrodes disposed in the sensor, the position detecting device detecting a position indicated by a stylus pen that generates an electric field based on electric field coupling between the stylus pen and the sensor based on the differential signal output from the differential amplifier circuit, the position detecting method comprising:

• selecting a first electrode to connect to the first input terminal of the differential amplifier circuit;
• and
• selecting a second electrode different from the first electrode to connect to the second input terminal of the differential amplifier circuit,
• wherein a distance between the first electrode and the second electrode is changed based on the differential signal output from the differential amplifier circuit.