Position detecting apparatus and position pointer
In a position detecting apparatus, electric power of a position pointer is turned on only when the position pointer is put within a particular range from a tablet to minimize consumption of a battery disposed in the position pointer. When the position pointer is brought close to the tablet, a control signal transmitted from the tablet is detected by a resonant circuit of the position pointer, and MOSFETs serving as a power switch are turned on by the detected signal. In response, electric power is supplied from a battery via the MOSFETs to circuit elements of the position pointer, and thus an operation of the position pointer starts.
1. A position detecting apparatus for detecting a position on a tablet pointed to by a position pointer,
a tablet comprising a control signal transmitter for transmitting a control signal to a position pointer to start an operation of the position pointer when the position pointer is within a predetermined range of a surface of said tablet, and
a position pointer comprising:
a battery supplying power to operate said position pointer;
a control signal detection unit for detecting the control signal transmitted from said tablet; and
a power control module for turning on or off electric power supplied from a battery in accordance with the control signal detected by said control signal detection unit,
wherein the position pointed to by said position pointer is detected by transmitting and receiving signals using at least one of electromagnetic and electrostatic coupling between said tablet and said position pointer.
2. The position detecting apparatus of claim 1 , said tablet further comprising a detector for detecting a position pointed to by said position pointer based upon a signal transmitted from said position pointer.
3. The position detecting apparatus of claim 1 , wherein said position pointer power control module turns on the electric power supplied from the battery when a signal level detected by said control signal detection unit is at least equal to a threshold value and the power control module turns off the electric power supplied from the battery when the signal level is lower than the threshold value.
4. The position detecting apparatus of claim 1 , said position pointer further comprising at least a resonant circuit including a coil and a capacitor adapted to receive a radiated signal from said tablet with particular timing, to control a resonant characteristic of said resonant circuit with the particular timing, and to point to a position on said tablet by using at least one of electromagnetic and electrostatic coupling between said position pointer and said tablet.
5. A method of operating a position detecting apparatus for detecting a position on a tablet identified by a position pointer, the method comprising:
providing a tablet including a control signal transmitter for transmitting a control signal to a position pointer to start an operation of the position pointer when the position pointer is within a predetermined range of a surface of the tablet;
providing a position pointer including a battery serving as a power supply with which to operate the position pointer, a control signal detection unit for detecting the control signal transmitted from the tablet, and a power control module for turning on or off electric power from the battery in accordance with the control signal detected by the control signal detection unit;
transmitting and receiving signals using at least one of electromagnetic and electrostatic coupling between the tablet and the position pointer to detect the position pointed to by said position pointer;
detecting a position pointed to by said position pointer based upon a signal transmitted from said position pointer.
6. The method of operating a position detecting apparatus of claim 5 , including the further step of: providing with the tablet a detector for detecting a position pointed to by the position pointer based on a signal transmitted from the position pointer.
7. The method of operating a position detecting apparatus of claim 5 , including the step of turning on the electric power supplied from the battery when a signal level detected by the control signal detection unit is at least equal to a threshold value and the power control module turns off the electric power supplied from the battery when the signal level is lower than the threshold value.
8. The method of operating a position detecting apparatus of claim 5 , including the step of providing with the position pointer at least a resonant circuit including a coil and a capacitor adapted to receive a radiated signal from the tablet with particular timing to control a resonant characteristic of the resonant circuit with the particular timing and to point to a position on the tablet by using at least one of electromagnetic and electrostatic coupling between the position pointer and the tablet.
9. A system for detecting a position in a position detecting device, comprising:
at least one tablet and at least one position pointer;
said tablet comprising a control signal transmitter for transmitting a control signal to said position pointer to start an operation of said position pointer when said position pointer is within a predetermined range from a surface of said tablet; and
said position pointer including a battery supplying power to operate said position pointer, a control signal detection unit for detecting the control signal transmitted from said tablet, and a power control module for turning on and off electric power supplied from the battery in accordance with the control signal detected by the control signal detection unit;
wherein the position pointed to by said position pointer is detected by transmitting and receiving signals using at least one of electromagnetic and electrostatic coupling between said tablet and said position pointer.
10. The position detecting system of claim 9 , wherein said tablet further comprises a detector for detecting a position pointed to by said position pointer based on a signal transmitted from said position pointer.
11. The position detecting system of claim 9 , wherein said position pointer power control module turns on the electric power supplied from said battery when a signal level detected by said control signal detection unit is at least equal to a threshold value and the power control module turns off the electric power supplied from said battery when the signal level is lower than the threshold value.
12. The position detecting apparatus of claim 9 , wherein said position pointer further comprises a resonant circuit including a coil and a capacitor adapted to receive a radiated signal from said tablet with particular timing, to control a resonant characteristic of the resonant circuit with the particular timing, and to point to a position on said tablet by using at least one electromagnetic and electrostatic coupling between said position pointer and said tablet.
13. A position pointing device for detecting a position on a tablet pointed to by the position pointing device,
the position pointing device comprising:
a battery supplying power to operate the position pointing device;
a control signal receiver for receiving the control signal transmitted from a tablet to the position pointing device using at least one of electromagnetic and electrostatic coupling;
a control signal detection unit for detecting the control signal supplied from the control signal receiver;
a power control module for turning on and off electric power supplied from said battery in accordance with the control signal detected by said control signal detection unit,
wherein the position pointed to by the position pointing device is detected on the tablet, and
wherein an operation of the position pointing device starts when the position pointing device is within a predetermined range from a surface of the tablet.
14. The position detecting device of claim 13 , wherein the position pointer power control module turns on the electric power supplied from said battery when a signal level detected by said control signal detection unit is at least equal to a threshold value and said power control module turns off the electric power supplied from said battery when the signal level is lower than the threshold value.
15. The position detecting device of claim 13 , wherein said position pointer further comprises at least a resonant circuit including a coil and a capacitor adapted to receive a radiated signal from the tablet with particular timing, to control a resonant characteristic of the resonant circuit with the particular timing, and to point to a position on the tablet using at least one of electromagnetic and electrostatic coupling between the position pointer and the tablet.