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 of a device, the pen-shaped position indicator comprising:
a pen-shaped body having a pen-tip portion;
a coil;
a driving power production circuit configured to produce a DC voltage from an induced signal in the coil, wherein the induced signal is generated by a wireless interaction with the device;
a signal production circuit connected to the driving power production circuit and configured to generate a signal based on the DC voltage to form a capacitive relationship between the pen-shaped body and the device;
a first electrode arranged at a first position of the pen-tip portion; 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 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 signal production circuit generates signals which are different in type from each other.
6. The pen-shaped position indicator according to claim 1 , wherein the signal production circuit generates signals which are of the same type but have different signal properties from each other.
7. The pen-shaped position indicator according to claim 6 , wherein the signals are based on codes having code patterns different from each other.
8. A pen-shaped position indicator configured to capacitively couple with a sensor surface of a device, the pen-shaped position indicator comprising:
a pen-shaped body having a pen-tip portion;
a coil;
a driving power production circuit configured to produce a DC voltage from an induced signal in the coil, wherein the induced signal is generated by a wireless interaction with the device;
a signal production circuit connected to the driving power production circuit and configured to generate first and second signals based on the DC voltage to form capacitive relationships between the pen-shaped body and the device;
a first electrode arranged at a first position of the pen-tip portion; 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 first signal generated by the signal production circuit is supplied to the first electrode and the second signal generated by the signal production circuit is controllably supplied to the second and third electrodes, so that with the first signal and the second signal, 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.
9. The pen-shaped position indicator according to claim 8 , wherein the first electrode includes a conductive pen tip, to which the signal production circuit transmits the first signal.
10. The pen-shaped position indicator according to claim 8 , wherein the first and second signals are of the same type but have different signal properties from each other.
11. A method of detecting position information of a pen-shaped position indicator, the method comprising:
producing a DC voltage from an induced signal in a coil, wherein the induced signal is generated by a wireless interaction with a device;
generating first and second signals based on the DC voltage to form capacitive relationships between the pen-shaped body and the device;
forming a first capacitive relationship between a sensor surface of the device and a first electrode, which is arranged at a first position of a pen-tip portion of the pen-shaped position indicator; and
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, in operation, the first signal is supplied to the first electrode and the second signal is controllably supplied to the second electrode, so that with the first signal and the second signal, the first and second electrodes are configured to form first and second capacitive relationships with the sensor surface, respectively,
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 used to obtain angle information of the pen-shaped position indicator.
12. The method 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 method according to claim 11 , 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.
14. The method according to claim 11 , wherein the second electrode comprises plural electrode pieces arranged to surround the axis of the pen-shaped position indicator.
15. The method according to claim 11 , wherein the second electrode is arranged to surround the axis of the pen-shaped position indicator.
16. The method according to claim 11 , wherein the first and second signals are different in type from each other.
17. The method according to claim 11 , wherein the first and second signals are of the same type but have different signal properties from each other.
18. A method of detecting position information of a pen-shaped position indicator, the method comprising:
producing a DC voltage from an induced signal in a coil which is generated by a wireless interaction with a device;
generating first and second signals based on the DC voltage to form capacitive relationships between the pen-shaped body and the device; and
forming first, second and third capacitive relationships between a sensor surface of the device and first, second and third electrodes, respectively, which are arranged near a pen-tip portion of the pen-shaped position indicator, wherein, in operation, the first signal is supplied to the first electrode and the second signal is controllably supplied to at least one of the second electrode and the third electrode, so that with the first signal and the second signal, the first, second and third electrodes are configured to form the first, second and third capacitive relationships with the sensor surface, respectively, 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 used to obtain angle information of the pen-shaped position indicator.
19. The method according to claim 18 , 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.