Pointer, position detection apparatus and position detection method
A position detection apparatus of the electrostatic coupling type is provided, to detect not only a position of a pointer but also information other than the position information such as, for example, pointer pressure or side switch information. The pointer transmits two codes such that a pressure applied to a pen tip is associated with a time difference between the two codes. A position detector carries out a correlation matching operation between signals generated in reception conductors and correlation calculation codes corresponding to the two codes, to thereby detect a position on a sensor section pointed to by the pointer from a result of the correlation matching operation and based on at least one of the codes. The position detector further includes a pressure calculation circuit for detecting pressure applied to the pointer, which is associated with the time difference between the two codes, from the result of the correlation matching operation calculated by the correlation matching operation and based on the two codes.
1. A pen-shaped position indicator configured to capacitively couple with a sensor surface, the pen-shaped position indicator comprising:
a pen-shaped body having a pen-tip portion;
a signal production circuit configured to generate first and second signals that are distinguishable from each other;
a first electrode arranged at a first position of the pen-tip portion to which the first signal generated by the signal production circuit is supplied; and
a second electrode arranged at a second position of the pen-tip portion different from the first position, the second position being off an axis of the pen-shaped position indicator, wherein, in operation, the second signal generated by the signal production circuit is supplied to the second electrode while the first signal generated by the signal production circuit is supplied to the first electrode;
wherein the first and second electrodes are configured to form first and second capacitive relationships with the sensor surface, respectively, to generate detection signals in the sensor surface from which a first detection signal and a second detection signal distinguishable from each other are extracted and used to obtain angle information of the pen-shaped position indicator.
2. The pen-shaped position indicator according to claim 1 , wherein the first and second electrodes are arranged at the first and second positions that are different along the axis of the pen-shaped position indicator.
3. The pen-shaped position indicator according to claim 1 , wherein the second electrode comprises plural electrode pieces arranged to surround the axis of the pen-shaped position indicator.
4. The pen-shaped position indicator according to claim 1 , wherein the second electrode is arranged to surround the axis of the pen-shaped position indicator.
5. The pen-shaped position indicator according to claim 1 , wherein the angle information is a tilt angle of the pen-shaped position indicator relative to the sensor surface.
6. The pen-shaped position indicator according to claim 1 , wherein the angle information is a rotation angle of the pen-shaped position indicator about the axis of the pen-shaped position indicator.
7. The pen-shaped position indicator according to claim 1 , wherein the first and second signals are different in type from each other.
8. The pen-shaped position indicator according to claim 1 , wherein the first and second signals are of the same type but have different signal properties from each other.
9. The pen-shaped position indicator according to claim 8 , wherein the different signal properties are based on codes having code patterns different from each other.
10. The pen-shaped position indicator according to claim 1 , further comprising:
a coil configured to receive an excitation signal; and
a power generation circuit configured to generate a drive voltage based on the excitation signal;
wherein the drive voltage is supplied to the signal production circuit to generate the first and second signals.
11. A pen-shaped position indicator configured to capacitively couple with a sensor surface, the pen-shaped position indicator comprising:
a pen-shaped body having a pen-tip portion;
a signal production circuit configured to generate first and second signals;
a first electrode arranged at a first position of the pen-tip portion to which the first signal generated by the signal production circuit is supplied; and
second and third electrodes arranged near the pen-tip portion to surround an axis of the pen-shaped position indicator, wherein, in operation, the second signal generated by the signal production circuit that is distinguishable from the first signal is supplied to at least one of the second and third electrodes while the first signal generated by the signal production circuit is supplied to the first electrode;
wherein the first, second and third electrodes are configured to form first, second and third capacitive relationships with the sensor surface, respectively, to generate detection signals in the sensor surface from which a first detection signal, a second detection signal, and a third detection signal distinguishable from each other are extracted and used to obtain angle information of the pen-shaped position indicator.
12. The pen-shaped position indicator according to claim 11 , wherein the first electrode includes a conductive pen tip, to which the signal production circuit transmits the first signal.
13. The pen-shaped position indicator according to claim 11 , wherein the angle information is a tilt angle of the pen-shaped position indicator relative to the sensor surface.
14. The pen-shaped position indicator according to claim 11 , wherein the angle information is a rotation angle of the pen-shaped position indicator about the axis of the pen-shaped position indicator.
15. The pen-shaped position indicator according to claim 11 , wherein the first and second signals are of the same type but have different signal properties from each other.
16. A method of detecting angle information of a pen-shaped position indicator, the method comprising:
forming a first capacitive relationship between a sensor surface and first electrode, which is arranged at a first position of a pen-tip portion of the pen-shaped position indicator and is supplied with a first signal generated by a signal production circuit;
forming a second capacitive relationship between the sensor surface and a second electrode, which is arranged at a second position of the pen-tip portion different from the first position and off an axis of the pen-shaped position indicator, wherein the second electrode, in operation, is supplied with a second signal generated by the signal production circuit that is distinguishable from the first signal while the first signal generated by the signal production circuit is supplied to the first electrode;
wherein the first and second capacitive relationships generate detection signals in the sensor surface from which a first detection signal and a second detection signal distinguishable from each other are extracted and
obtaining angular information of the pen-shaped position indicator based on the first detection signal and the second detection signal.
17. The method according to claim 16 , wherein the first electrode includes a conductive pen tip, to which the signal production circuit transmits the first signal.
18. The method according to claim 16 , wherein the first and second electrodes are arranged at the first and second positions that are different along the axis of the pen-shaped position indicator.
19. The method according to claim 16 , wherein the second electrode comprises plural electrode pieces arranged to surround the axis of the pen-shaped position indicator.
20. The method according to claim 16 , wherein the second electrode is arranged to surround the axis of the pen-shaped position indicator.
21. The method according to claim 16 , wherein the angle information is a tilt angle of the pen-shaped position indicator relative to the sensor surface.
22. The method according to claim 16 , wherein the angle information is a rotation angle of the pen-shaped position indicator about the axis of the pen-shaped position indicator.
23. The method according to claim 16 , wherein the first and second signals are different in type from each other.
24. The method according to claim 16 , wherein the first and second signals are of the same type but have different signal properties from each other.
25. A method of detecting angle information of a pen-shaped position indicator, the method comprising:
forming first, second and third capacitive relationships between a sensor surface and first, second and third electrodes, respectively, which are arranged near a pen-tip portion of the pen-shaped position indicator, wherein the first electrode is supplied with a first signal generated by a signal production circuit while at least one of the second and third electrodes is supplied with a second signal generated by the signal production circuit that is distinguishable from the first signal, and wherein the first, second and third capacitive relationships generate detection signals in the sensor surface from which a first detection signal, a second detection signal, and a third detection signal distinguishable from each other are extracted; and
obtaining angular information of the pen-shaped position indicator based on the first detection signal, the second detection signal, and the third detection signal.
26. The method according to claim 25 , comprising:
forming a capacitive relationship between the sensor surface and the pen-tip portion including a conductive pen tip, to which the first signal is supplied.
27. The method according to claim 25 , wherein the angle information is a tilt angle of the pen-shaped position indicator relative to the sensor surface.
28. The method according to claim 25 , wherein the angle information is a rotation angle of the pen-shaped position indicator about the axis of the pen-shaped position indicator.
29. The method according to claim 25 , wherein the first and second signals are different in type from each other.
30. The method according to claim 25 , wherein the first and second signals are of the same type but have different signal properties from each other.