Position detecting device and computer including the same

• US 20070227785A1
• Filed: 03/22/2007
• Published: 10/04/2007
• Est. Priority Date: 03/23/2006
• Status: Active Grant

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Wacom Co Limited (Wacom)
• Inventors: Katsurahira, Yuji
• Granted Patent: US 8,368,669 B2
• Time in Patent Office: Days
• US Class Current: 178/18.70
• CPC Class Codes: G06F 1/32 Means for saving power
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

A position detecting device is provided. The position detecting device includes a position pointer which transmits a position-pointing signal using a power supply stored in a rechargeable power storage unit, and a tablet which detects a position pointed to by the position pointer when receiving the position-pointing signal. The position pointer includes a coil, a charging circuit for charging the power storage unit, and a transmitter for transmitting the position-pointing signal. The tablet includes an excitation coil wound around a periphery of a position detecting area of the tablet, an excitation circuit for supplying an alternating voltage to the excitation coil, a position-pointing signal detector for detecting the position-pointing signal received from the position pointer, and an excitation controller for controlling a supply of the alternating voltage to the excitation coil based on the detected position-pointing signal.

Claims

1. A position detecting device, comprising:

a position pointer which transmits a position-pointing signal using a power supply stored in a rechargeable power storage unit, said position pointer including a coil, a charging circuit for charging said power storage unit, and a transmitter for transmitting said position-pointing signal; and

a tablet which detects a position pointed to by said position pointer when receiving said position-pointing signal, said tablet including an excitation coil wound around a periphery of a position detecting area, an excitation circuit for supplying an alternating voltage to said excitation coil, a position-pointing signal detector for detecting said position-pointing signal received from said position pointer, and an excitation controller for controlling a supply of the alternating voltage to said excitation coil based on said detected position-pointing signal.

2. The position detecting device according to claim 1, wherein said tablet is integrally formed with a display device.

3. The position detecting device according to claim 1, wherein said excitation controller supplies the alternating voltage to said excitation coil when the position pointed to by said position pointer is detected within a predetermined distance range from where said excitation coil is arranged.

4. The position detecting device according to claim 1, wherein the coil in said position pointer receives a charging signal produced by said alternating voltage from the excitation coil of said tablet and transmits said position pointing signal to said tablet.

5. The position detecting device according to claim 1, wherein said position pointer includes a resonant circuit configured with a coil and a capacitor.

6. The position detecting device according to claim 1, wherein the power storage unit of said position pointer is an electric double-layer capacitor.

7. A position detecting apparatus for detecting a position of a position pointer, the apparatus comprising:

a tablet having a plurality of conductors disposed on a surface thereof, the plurality of conductors including a plurality of detecting conductors to detect a position of the position pointer and at least one charging conductor to charge the position pointer.

8. The position detecting apparatus according to claim 7, wherein the at least one charging conductor charges the position pointer when the position pointer is within a vicinity of the at least one charging conductor.

9. The position detecting apparatus according to claim 7, wherein the at least one charging conductor is disposed around a periphery of the tablet to surround the plurality of detecting conductors.

10. The position detecting apparatus according to claim 7, wherein the detecting conductors receive a transmission data signal from the position pointer and the position pointer receives a charging signal from the at least one charging conductor.

11. The position detecting apparatus according to claim 7, further comprising:

a control unit to control the at least one charging conductor to transmit a charging signal to the position pointer if the detecting conductors detect that the position pointer is in a peripheral portion of a position detecting area of the tablet.

12. The position detecting apparatus according to claim 7, wherein:

the detecting conductors receive a continuous transmission signal from the position pointer during a position detecting period to detect the position of the position pointer; and

the at least one charging conductor transmits a charging signal to the position pointer during a charging period to charge a battery in the position pointer, the charging period beginning at a time subsequent to completion of the position detecting period.

13. The position detecting apparatus according to claim 12, wherein the position pointer transmits operational data to the detecting conductors during a data transmission period occurring between the position detecting period and the charging period.

14. The position detecting apparatus according to claim 7, further comprising:

a processing unit in communication with the tablet, the processing unit controlling flow of electric current to the at least one charging conductor based on whether the position pointer is detected to be close to the at least one charging conductor.

15. The position detecting apparatus according to claim 14, further comprising:

an oscillator associated with the tablet to generate an oscillation signal of a predetermined frequency; and

a switching unit connected between the oscillator and the at least one charging conductor, the switching unit receiving a control signal from the processing unit and being operable between a first state in which the switching unit provides the generated oscillation signal to the at least one charging conductor and a second state in which the switching unit does not provide the generated oscillation signal to the at least one charging conductor.

16. A position detecting apparatus, comprising:

a tablet having electromagnetic detecting conductors arranged along a surface thereof, the electromagnetic detecting conductors interacting with a pointing device,

wherein the surface of the tablet includes a first region in which a position of the pointing device is detected and a second region in which the position of the pointing device is detected and a battery of the pointing device is recharged.

17. The position detecting apparatus according to claim 16, wherein the first region is a central portion of the tablet and the second region is a peripheral portion of the tablet that surrounds the central portion.

18. The position detecting apparatus according to claim 16, wherein the pointing device transmits position signals when positioned in either of the first and second regions, and the pointing device receives a charging signal from the tablet when positioned in the second region.

19. A position detecting apparatus, comprising:

a position pointer having a rechargeable power supply; and

a tablet having a plurality of conductors disposed on a surface thereof, the plurality of conductors including;

a plurality of detecting conductors to detect a position of the position pointer based on a position signal of a first signal power received from the position pointer, and

at least one charging conductor to charge the power supply of the position pointer by transmitting a charging signal of a second signal power to the position pointer, the second signal power being greater than the first signal power.

20. The position detecting apparatus according to claim 19, wherein the position signal is transmitted during a first time period and the charging signal is transmitted during a second time period that begins after the first time period has ended.

21. A position detecting apparatus, comprising:

a position pointer having a rechargeable power supply; and

a tablet having a plurality of conductors disposed on a surface thereof, the plurality of conductors including a plurality of detecting conductors to detect a position of the position pointer and at least one charging conductor to charge the power supply of the position pointer when the position pointer is within a vicinity of the at least one charging conductor.

22. The position detecting apparatus according to claim 21, wherein the position pointer comprises:

a resonant circuit to receive the charging signal; and

a rechargeable battery to receive current from the resonant circuit, in response to the charging signal.

23. The position detecting apparatus according to claim 22, wherein the position pointer further comprises:

a microprocessor having a power input terminal; and

a switch to regulate a connection between the rechargeable battery and the power input terminal of the microprocessor.

24. The position detecting apparatus according to claim 23, wherein the position pointer further comprises:

a diode forward biased from the resonant circuit to the rechargeable battery;

a capacitor disposed at the power input terminal of the microprocessor to receive charge from the rechargeable battery when the switch is closed; and

a voltage detector to detect an actual voltage at the capacitor and to control the switch to open an close to maintain a predetermined voltage level at the capacitor.

25. A pointing device usable with a position detecting apparatus having a tablet with a plurality of detecting conductors and at least one charging conductor, the device comprising:

a housing;

a resonance circuit to transmit a position signal to the detecting conductors of the tablet and to receive a charging signal from the at least one charging conductor of the tablet; and

a rechargeable battery to receive an electric current from the resonance circuit when the charging signal is being received.

26. The pointing device according to claim 25, wherein the resonance circuit transmits the position signal during a first time period and receives the charging signal during a second time period.

27. The pointing device according to claim 25, further comprising:

a microprocessor having a power input terminal; and

a switch to regulate a connection between the rechargeable battery and the power input terminal of the microprocessor to maintain a predetermined voltage level at the power input terminal.

33. The computer according to claim 27, wherein the power storage of said position pointer is an electric double-layer capacitor.

28. A computer, comprising:

a position detecting device, including

a position pointer which transmits a position-pointing signal using a power supply stored in a rechargeable power storage unit, said position pointer including a coil, a charging circuit for charging said power storage unit, and a transmitter for transmitting said position-pointing signal; and

a tablet which detects a position pointed to by said position pointer when receiving said position-pointing signal,

said tablet including an excitation coil wound around a periphery of a position detecting area, an excitation circuit for supplying an alternating voltage to said excitation coil, a position-pointing signal detector for detecting said position-pointing signal received from said position pointer, and an excitation controller for controlling a supply of the alternating voltage to said excitation coil based on said detected position-pointing signal.

29. The computer according to claim 28, further comprising:

a display device for displaying images, the display device being integrally formed with said tablet.

30. The computer according to claim 28, wherein said excitation controller supplies the alternating voltage to said excitation coil when the position pointed to by said position pointer is within a predetermined distance range from where said excitation coil is arranged.

31. The computer according to claim 28, wherein the coil of said position pointer receives a charging signal produced by said alternating voltage from the excitation coil of said tablet and transmits said position pointing signal to said tablet.

32. The computer according to claim 28, wherein said position pointer includes a resonant circuit configured with a coil and a capacitor.

34. A method of operating a position detecting apparatus including a position pointer having a rechargeable power supply and a tablet having a plurality of detecting conductors to detect a position of the position pointer and at least one charging conductor to charge the power supply of the position pointer, the method comprising:

receiving a position signal from the position pointer at the detecting conductors;

determining a position of the position pointer with respect to the tablet based on the received position signal; and

transmitting a charging signal from the at least one charging conductor to the position pointer if it is determined that the position of the position pointer is within a predetermined distance from the at least one charging conductor.

35. The method according to claim 34, wherein the charging signal has a signal power that is greater than a signal power of the position signal.

36. The method according to claim 34, wherein the at least one charging conductor is an excitation coil wound around a peripheral portion of the tablet, and the determining of the position of the position pointer with respect to the tablet based on the received position signal comprises determining whether the position pointer is disposed in the peripheral portion of the tablet.