Position detecting device and computer including the same

• US 8,368,669 B2
• Filed: 03/22/2007
• Issued: 02/05/2013
• Est. Priority Date: 03/23/2006
• Status: Active Grant

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Wacom Co Limited (Wacom)
• Inventors: Katsurahira, Yuji
• Primary Examiner(s): Lefkowitz, Sumati
• Assistant Examiner(s): Tung, David
• Application Number:
  US11/723,956
• Publication Number:
  US 20070227785A1
• Time in Patent Office: 2,147 Days
• Field of Search: 345/179, 455/41.1
• US Class Current: 345/179
• 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 to transmit a position-pointing signal using power supplied from a rechargeable power storage unit of said position pointer; and

a tablet to detect a position pointed to by said position pointer using the position-pointing signal transmitted from said position pointer,

wherein said position pointer comprises,

a coil for generating power from an alternating magnetic field transmitted from an excitation coil of said tablet,

a charging circuit for charging said rechargeable power storage unit using the power transmitted through said coil of said position pointer, and

a transmitter for transmitting the position-pointing signal to said tablet, and wherein said tablet comprises

said excitation coil wound around a periphery of a position detecting area of said tablet,

an excitation circuit to drive said excitation coil for generating the alternating magnetic field,

a position-pointing signal detector to detect the position-pointing signal from said position pointer, and

an excitation controller to control said excitation circuit to cause said excitation coil to generate the alternating magnetic field based on a determination that said position pointer is in a peripheral portion within said position detecting area and to cause the excitation coil not to generate the alternating magnetic field based on a determination that said position pointer is in a central portion of said position detecting area, said peripheral portion surrounding said central portion being defined by specific x and y coordinates within said position detecting area, the determinations being made based on detection of said specific x and y coordinates of the position-pointing signal by said position-pointing signal detector, said excitation controller controlling said excitation circuit to cause said excitation coil to generate the alternating magnetic field for charging said rechargeable power storage unit using said charging circuit when the determination is that said position pointer is in said peripheral portion within said position detecting area of said tablet,

wherein said excitation controller initiates a charging operation for a predetermined period of time when said position pointer is located in said peripheral portion and initiates a transmission stop when said position pointer is not located in said peripheral portion.

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

3. The position detecting device according to claim 1, wherein said position pointer further comprises a resonant circuit configured with said coil and a capacitor for receiving the power from said tablet using the alternating magnetic field.

4. The position detecting device according to claim 3, wherein said resonant circuit is shared as said transmitter for transmitting said position-pointing signal to said tablet.

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

6. The position detecting device according to claim 1, wherein said position pointer further comprises a processing unit driven by a predetermined voltage that controls said transmitter, a voltage detector used for maintaining said predetermined voltage, and a switch connected to said rechargeable power storage unit, and wherein the ON/OFF operation of said switch is controlled by said processing unit for maintaining said predetermined voltage based on the voltage detection of said voltage detector.

7. The position detecting device according to claim 1, wherein said position pointer further comprises a microprocessor for performing operations comprising a continuous transmission period for facilitating detection of said position pointer by said tablet, a data transmission period for transmitting writing information from said position pointer to said tablet, and a position indicator charging period for permitting said excitation coil to charge said position indicator, wherein said position detecting device is configured to perform said operations while said position pointer is in said peripheral portion within said position detecting area.

8. A position detecting device comprising:

a display device;

a position pointer to transmit a position-pointing signal using power supplied from a rechargeable power storage unit of said position pointer; and

a sensor to detect a position pointed to by said position pointer using the position-pointing signal received from said position pointer,

wherein said position pointer comprises

a coil for generating power from an alternating magnetic field transmitted from an excitation coil of said sensor,

a charging circuit for charging said rechargeable power storage unit using the power transmitted through said coil, and

a transmitter for transmitting the position-pointing signal, and

wherein said sensor comprises said excitation coil wound around a periphery of a position detecting area of said sensor,

an excitation circuit to drive said excitation coil for generating the alternating magnetic field,

a position-pointing signal detector to detect the position-pointing signal from said position pointer; and

an excitation controller to control said excitation circuit to cause said excitation coil to generate the alternating magnetic field based on a determination that said position pointer is in a peripheral portion within said position detecting area and to cause the excitation coil not to generate the alternating magnetic field based on a determination that said position pointer is in a central portion of said position detecting area, said peripheral portion being defined by specific x and y coordinates values surrounding said central portion, the determinations being made based on detection of the position-pointing signal by said position pointing signal detector, said excitation controller controlling said excitation circuit to cause said excitation coil to generate the alternating magnetic field for charging said rechargeable power storage unit using said charging circuit when the determination is that said position pointer is in said peripheral portion within said position detecting area of said sensor,

wherein said excitation controller initiates a charging operation for a predetermined period of time when said position pointer is located in said peripheral portion and initiates a transmission stop when said position pointer is not located in said peripheral portion.

9. The position detecting device according to claim 8, wherein said position pointer further comprises a microprocessor for performing operations comprising a continuous transmission period for facilitating detection of said position pointer by said tablet, a data transmission period for transmitting writing information from said position pointer to said tablet, and a position indicator charging period for stopping transmission of said writing information and permitting said excitation coil to charge said position indicator, wherein said position detecting device is configured to perform said operations while said position pointer is in said peripheral portion within said position detecting area.

10. A method of operating a position detecting apparatus including a position pointer having a rechargeable power supply, comprising:

providing the position pointer to transmit a position-pointing signal using power supplied from a rechargeable power storage unit;

providing a display device including a sensor to detect a position pointed to by the position pointer using the position-pointing signal received from the position pointer,

the position pointer comprising a coil for generating power from an alternating magnetic field, a charging circuit for charging the rechargeable power storage unit using the power transmitted through the coil, and a transmitter that transmits the position-pointing signal to the sensor, and

the sensor comprising an excitation coil wound around a periphery of a position detecting area of the sensor, an excitation circuit to drive the excitation coil for generating the alternating magnetic field, a position-pointing signal detector to detect the position-pointing signal from the position pointer, and an excitation controller for controlling the excitation circuit;

controlling the excitation circuit to cause the excitation coil to generate the alternating magnetic field based on a determination that the position pointer is in a peripheral portion within the position detecting area and to cause the excitation coil not to generate the alternating magnetic field based on a determination that the position pointer is in a central portion of the position detecting area, the peripheral portion being defined by specific x and y coordinates surrounding the central portion, the determinations being made based on detection of the position-pointing signal by the position pointing signal detector, the excitation controller controlling the excitation circuit to cause the excitation coil to generate the alternating magnetic field for charging the rechargeable power storage unit using the charging circuit when the determination is that the position pointer is in said peripheral portion within said position detecting area of the sensor,

initiating a charging operation for a predetermined period of time when said position pointer is located in said peripheral portion, and

initiates a transmission stop when said position pointer is not located in said peripheral portion.

11. The method according to claim 10, wherein said position 10 further comprises a resonant circuit configured with said coil and a capacitor for receiving the power from said tablet using the alternating magnetic field.

12. The method according to claim 10, wherein the position pointer further comprises a processing unit driven by a predetermined voltage that controls the transmitter, a voltage detector for maintaining the predetermined voltage, and a switch connected to the rechargeable power storage unit, the ON/OFF operation of the switch being controlled by the processing unit for maintaining the predetermined voltage based on the voltage detection of the voltage detector.

13. The method according to claim 10, wherein, when the position pointer is in the peripheral portion within the position detecting area, said method further comprises continuously transmitting a signal from the position pointer to the tablet, subsequently transmitting writing information to the tablet, and charging the position indicator with the excitation coil.

14. A computer system, comprising:

a display panel to display images on a display side thereof;

a central processing unit to control said display panel;

a position detecting device, comprising a position pointer to transmit a position-pointing signal using power supplied from a rechargeable power storage unit of said position pointer, and a tablet to detect a position pointed to by said position pointer using the position-pointing signal transmitted from said position pointer,

wherein said position pointer comprises

a coil for generating power from an alternating magnetic field transmitted from an excitation coil of said tablet,

a charging circuit for charging said rechargeable power storage unit using the power transmitted through said coil, and

a transmitter for transmitting the position-pointing signal to said tablet, and

wherein said tablet comprises

said excitation coil wound around a periphery of a position detecting area of said tablet,

an excitation circuit to drive said excitation coil for generating the alternating magnetic field,

a position-pointing signal detector to detect the position-pointing signal from said position pointer, and

an excitation controller to control said excitation circuit to cause said excitation coil to generate the alternating magnetic field based on a determination that said position pointer is in a peripheral portion within said position detecting area and to cause the excitation coil not to generate the alternating magnetic field based on a determination that said position pointer is in a central portion of said position detecting area, said peripheral portion being defined by specific x and y coordinated surrounding said central portion, the determination being made based on detection of the position-pointing signal by said position-pointing signal detector, said excitation controller controlling said excitation circuit to cause said excitation coil to generate the alternating magnetic field for charging said rechargeable power storage unit using said charging circuit when the determination is that said position pointer is in said peripheral portion within said position detecting area of said tablet,

wherein said excitation controller initiates a charging operation for a predetermined period of time when said position pointer is located in said peripheral portion and initiates a transmission stop when said position pointer is not located in said peripheral portion.

15. The computer system according to claim 14, wherein said tablet is integrally formed with a display device.

16. The computer system according to claim 14, wherein said position pointer further comprises a resonant circuit configured with said coil and a capacitor for receiving the power from said tablet using the alternating magnetic field.

17. The computer system according to claim 14, wherein said position pointer further comprises a microprocessor for performing operations comprising a continuous transmission period for facilitating detection of said position pointer by said tablet, a data transmission period for transmitting writing information from said position pointer to said tablet, and a position indicater charging period for stopping transmission of said writing information and permitting said excitation coil to charge said position indicator, wherein said position detecting device is configured to perform said operations while said position pointer is in said peripheral portion within said position detecting area.