Position indicator including control circuit that causes electrode to switch from being connected to alternating potential to being connected to fixed potential in response to determining that pen pressure is detected
A position indicator that electrostatically interacts with a sensor includes: a casing having a pen shape; a conductive core body including a pen tip that protrudes from an opening on one end in the axial direction of the casing; a conductor surrounding the core body; a signal transmitting circuit which, in operation, generates a signal that electrostatically interacts with the sensor, and supplies the generated signal to the core body; and a control circuit which, in operation, produces different electrostatic interactions with the sensor by performing a first control operation that sets the conductor in a state of being grounded while the signal is sent out from the pen tip of the core body to the sensor, and performing a second control operation that sets the conductor in a state different from the state of being grounded.
1. A position indicator that electrostatically interacts with a position detecting device including a sensor, the position indicator comprising:
a casing having a pen shape;
an electrode within the casing;
a conductive core body including a pen tip that protrudes from an opening on one end in an axial direction of the casing, wherein the electrode surrounds the conductive core body;
a pen pressure detector which, in operation, detects a pen pressure applied to the conductive core body;
a control circuit which, in operation:
receives an instruction signal transmitted by the position detecting device,
determines whether the pen pressure is detected by the pen pressure detector, and
causes the electrode to switch from being connected to an alternating potential to being connected to a fixed potential in response to detecting device determining that the pen pressure is detected by the pen pressure detector.
2. The position indicator according to claim 1 , further comprising:
a signal generating circuit which, in operation, generates a transmission signal that is supplied to the conductive core body for electrostatically interacting with the sensor of the position detecting device.
3. The position indicator according to claim 2 , further comprising:
a switch circuit electrically coupled to the electrode,
wherein the control circuit, in operation, controls the switch circuit to cause the electrode to switch from being connected to the alternating potential to being connected to the fixed potential.
4. The position indicator according to claim 3 , wherein:
the switch circuit includes a first terminal, a second terminal, and a third terminal,
the first terminal is electrically coupled to the electrode,
the second terminal is electrically coupled to the signal generating circuit,
the third terminal is electrically coupled to the fixed potential, and
the control circuit, in operation, controls the switch circuit to cause the first terminal to switch from being electrically connected to the second terminal to being electrically connected to the third terminal.
5. The position indicator according to claim 2 , further comprising:
a charging element including a first terminal that, in operation, is electrically coupled to the signal generating circuit,
wherein the first terminal provides the fixed potential.
6. The position indicator according to claim 1 , further comprising:
a charging element having a first terminal and a second terminal,
wherein the first terminal or the second terminal of the charging element has the fixed potential.
7. The position indicator according to claim 6 ,
wherein the charging element is a rechargeable secondary battery or a capacitor.
8. The position indicator according to claim 6 ,
wherein the fixed potential is a ground potential.
9. The position indicator according to claim 1 , further comprising:
a charging element including a first terminal and a second terminal, wherein one of the first terminal or the second terminal has the fixed potential; and
a switch circuit electrically coupled to the one of the first terminal or the second terminal has the fixed potential,
wherein the control circuit, in operation, controls the switch circuit to cause the electrode to be selectively electrically coupled to the one of the first terminal or the second terminal has the fixed potential.
10. The position indicator according to claim 9 ,
wherein the fixed potential is a ground potential.
11. A method of operating a position indicator that electrostatically interacts with a position detecting device including a sensor, the position indicator including a casing having a pen shape and an electrode within the casing, the method comprising:
receiving an instruction signal transmitted by the position detecting device;
detecting a pen pressure applied to a conductive core body that protrudes from an opening on one end in an axial direction of the casing of the position indicator; and
causing the electrode to switch from being connected to an alternating potential to being connected to a fixed potential in response to the detecting the pen pressure applied to the conductive core body.
12. The method according to claim 11 , wherein:
the electrode surrounds the conductive core body, and
the method further comprises generating a transmission signal that is supplied to the conductive core body for electrostatically interacting with the sensor of the position detecting device.
13. The method according to claim 12 , wherein:
the position indicator includes a switch circuit electrically coupled to the electrode, and
causing the electrode to switch from being connected to the alternating potential to being connected to the fixed potential includes controlling the switch circuit.
14. The method according to claim 13 , wherein:
the switch circuit includes a first terminal, a second terminal, and a third terminal,
the first terminal is electrically coupled to the electrode,
the second terminal is electrically coupled to a signal generating circuit,
the third terminal is electrically coupled to the fixed potential, and
causing the electrode to switch from being connected to the alternating potential to being connected to the fixed potential includes generating a switching control signal that causes the first terminal to switch from being electrically connected to the second terminal to being electrically connected to the third terminal.
15. The method according to claim 12 , wherein:
the position indicator includes a charging element having a first terminal and a second terminal, and
the first terminal or the second terminal of the charging element has the fixed potential.
16. The method according to claim 15 ,
wherein the charging element is a rechargeable secondary battery or a capacitor.
17. The method according to claim 15 ,
wherein the fixed potential is a ground potential.
18. The method according to claim 11 , wherein:
the position indicator includes a charging element having a first terminal that, in operation, is electrically coupled to a signal generating circuit, and
the first terminal provides the fixed potential.
19. The method according to claim 11 , wherein:
the position indicator includes a charging element having a first terminal and a second terminal, wherein one of the first terminal or the second terminal has the fixed potential;
a switch circuit electrically coupled to the one of the first terminal or the second terminal that has the fixed potential, and
causing the electrode to switch from being connected to the alternating potential to being connected to the fixed potential includes generating a switching control signal that causes the electrode to be selectively electrically coupled to the one of the first terminal or the second terminal that has the fixed potential.
20. The method according to claim 19 ,
wherein the fixed potential is a ground potential.