Position input device and computer system

Abstract

A position input device is provided in which signals are transmitted from a position indicator, and signals transmitted from the position indicator are received by a position detector device. According to certain embodiments, an electrical double-layer capacitor, a charging circuit which charges the electrical double-layer capacitor, and a power transmission unit which relays and supplies to the charging circuit power supplied from a power supply unit external to the position indicator, are provided in the position indicator. In other embodiments the position input device has a built-in power supply unit, transmitting units, and a control unit for switching the transmitting units between energized and de-energized states. Also provided are position input systems and computer systems including the position input device, and methods of operating the position input device and the systems.

1 . A position input system, comprising: 
 a position indicator for transmitting signals; and    a position detector device for receiving signals transmitted from the position indicator,    wherein said position indicator comprises an electrical double-layer capacitor, a charging circuit which charges the electrical double-layer capacitor, and a power transmission unit which relays power supplied from a power supply unit external to the position indicator to said charging circuit.    
   
   
       2 . The position input system according to  claim 1 , wherein said power supply unit is external to said position detector.  
   
   
       3 . The position input system according to  claim 2 , wherein: 
 a coil is in said position indicator, and    said external power supply unit is an AC magnetic field generation unit.    
   
   
       4 . The position input system according to  claim 3 , wherein said power supply unit comprises a stand housing said AC magnetic field generation unit, wherein the stand is configured to enable setting of said position indicator.  
   
   
       5 . The position input system according to  claim 4 , wherein said stand comprises a detector switch for selectively supplying current to said power supply unit only when said position indicator is received by said stand.  
   
   
       6 . The position input system according  claim 3 , wherein the power supply unit is incorporated into said position detector device for permitting charging of the double-layer capacitor when said position indicator is placed above said position detector device.  
   
   
       7 . The position input system according to  claim 1 , further comprising a power supply assistance unit for receiving power from said electrical double-layer capacitor and supplying a prescribed voltage to said position indicator.  
   
   
       8 . The position input system according to  claim 1 , wherein said position detector device detects signals transmitted from said position indicator based on an electrostatic coupled state with said position indicator.  
   
   
       9 . The position input system according to  claim 1 , wherein said position detector device detects signals transmitted from said position indicator based on electromagnetic coupling with said position indicator.  
   
   
       10 . The position input system according to  claim 9 , wherein said position indicator comprises a resonance circuit comprising a coil and capacitor.  
   
   
       11 . The position input system according to  claim 1 , wherein said position indicator comprises: 
 a voltage detection unit for detecting when the voltage across said electrical double-layer capacitor has dropped to or below a prescribed voltage value, and    an information transmission unit for transmitting information indicating the detection of the drop in voltage by said voltage detection unit to said position detector device.    
   
   
       12 . A computer system, comprising: 
 a position input system comprising a position indicator for transmitting signals, and a position detector device for receiving signals transmitted from the position indicator;    a display device; and    a computer for processing positions detected by said position input device,    wherein said position indicator comprises 
 an electrical double-layer capacitor;  
 a charging circuit for charging the electrical double-layer capacitor; and  
 a power transmission unit for relaying and supplying, to said charging circuit, power from a power supply unit external to the position indicator.  
   
   
   
       13 . The computer system according to  claim 12 , further comprising: 
 a voltage detection unit for detecting when the voltage of said electrical double-layer capacitor has dropped to or below a prescribed voltage value; and    an information transmission unit for transmitting to said position detector device information indicating detection of the voltage drop by the voltage detection unit.    
   
   
       14 . The computer system according to  claim 13 , further comprising an AC magnetic field generation unit as said power supply unit, wherein a coil is provided in said position indicator, and wherein said computer is operable, upon reception by said position detector device of the information indicating detection of the voltage drop transmitted from said information transmission unit, to supply current to said AC magnetic field generation unit.  
   
   
       15 . The computer system according to  claim 13 , wherein the computer is operable, based on the information indicating detection of the voltage drop transmitted from said information transmission unit, to cause a report to be displayed by said display device.  
   
   
       16 . The computer system according to  claim 13 , further comprising an AC magnetic field generation unit as said power supply unit, wherein a coil is provided in said position indicator, and wherein said computer is operable to supply current to said AC magnetic field generation unit when a prescribed time has elapsed from the previous supply of current to said AC magnetic field generation unit.  
   
   
       17 . The computer system according to  claim 13 , further comprising a prompt to notify a user, based on the information indicating detection of the voltage drop transmitted from said information transmission unit, to charge said electrical double-layer capacitor, wherein said prompt is located on the position indicator.  
   
   
       18 . The computer system according to  claim 13 , further comprising a prompt to notify a user, based on the information indicating detection of the voltage drop transmitted from said information transmission unit, to charge said electrical double-layer capacitor, wherein said prompt is located on the position detector device.  
   
   
       19 . The computer system according to  claim 13 , further comprising a prompt to notify a user, based on the information indicating detection of the voltage drop transmitted from said information transmission unit, to charge said electrical double-layer capacitor, wherein said prompt is located on the power transmission unit.  
   
   
       20 . The computer system according to  claim 13 , further comprising an AC magnetic field generation unit as said power supply unit, wherein a coil is provided in said position indicator, and wherein said computer is operable to supply current to said AC magnetic field generation unit when the information indicating detection of the voltage drop transmitted by said information transmission unit is not received by said position detector device within a prescribed time from the previous passage of current to said AC magnetic field generation unit.  
   
   
       21 . The computer system according to  claim 12 , further comprising an AC magnetic field generation unit as said power supply unit, wherein a coil is provided in said position indicator, and wherein said computer is operable to issue a charging request and supply current to said AC magnetic field generation unit when a prescribed time has elapsed from the previous supply of current to said AC magnetic field generation unit.  
   
   
       22 . The computer system according to  claim 12 , further comprising an AC magnetic field generation unit as said power supply unit, wherein a coil is provided in said position indicator, and wherein said power supply unit comprises a detection switch which is activated when said position indicator is placed in a charging position with respect to said power supply unit.  
   
   
       23 . The computer system according to  claim 12 , wherein said power supply unit is integrated into said position detector device.  
   
   
       24 . A method of charging a position indicator of a position input system comprising the position indicator for transmitting signals and a position detector device for receiving signals transmitted by the position indicator, said method comprising the steps of: 
 providing a position indicator with an electrical double-layer capacitor, a charging circuit which charges the electrical double-layer capacitor, and a power transmission unit; and    supplying power from a power supply unit external to the position indicator, and causing the power transmission unit to relay the power to the charging circuit.    
   
   
       25 . A method of operating a computer system, comprising the steps of: 
 providing a position input system comprising a position indicator for transmitting signals, and a position detector device for receiving signals transmitted from the position indicator;    providing a computer for processing information based on positions detected by said position input device; and    supplying power from a power supply unit external to the position indicator, and causing the power transmission unit to relay the power to the charging circuit.    
   
   
       26 . The method according to  claim 25 , including the further steps of: 
 detecting when the voltage of the electrical double-layer capacitor has dropped to or below a prescribed voltage value; and    transmitting to the position detector device information indicating detection of the voltage drop.    
   
   
       27 . A position pointing device for transmitting a positioning signal to a position detecting tablet, the position pointing device comprising: 
 An integrated power supply unit;    a plurality of signal transmitting units provided at a plurality of portions of a position pointing device; and    a control unit for switching said plurality of signal transmitting units between energized and de-energized states.    
   
   
       28 . A position pointing device according to  claim 27 , wherein said plurality of signal transmitting units comprises first and second signal transmitting units respectively provided at opposite end portions of said position pointing device.  
   
   
       29 . The position pointing device according to  claim 28 , wherein said first and second signal transmitting units transmit a pen-point signal and an eraser signal, respectively.  
   
   
       30 . A position pointing device according to  claim 27 , wherein said control unit alternately switches said signal transmitting units between an energized state and a de-energized state.  
   
   
       31 . A position pointing device according to  claim 27 , further comprising: 
 a direction detecting unit for detecting the direction in which said position pointing device is arranged relative to the position detecting tablet, and wherein said control unit energizes whichever of the signal transmission units faces towards the position detector tablet based on a detected result of said direction detecting unit.    
   
   
       32 . A position pointing device according to  claim 31 , wherein said direction detecting unit comprises a stylus pressure detecting unit, and wherein said control unit is operable to energize whichever of the signal transmission units touches the position detector tablet based on detection by the stylus pressure detecting unit of a load greater than a predetermined load.  
   
   
       33 . A position pointing device according to  claim 32 , wherein said control unit is operable to sequentially operate said plurality of signal transmitting units if it is determined by the stylus pressure detecting unit that a load greater than said predetermined load is not detected from any one of said plurality of signal transmitting units.  
   
   
       34 . A position pointing device according to  claim 31 , wherein said direction detecting unit is a touch-sensitive sensor and said control unit is operable to energize whichever of said signal transmission units is associated with an end of the position pointing device which touches the position detecting tablet.  
   
   
       35 . A position pointing device for transmitting a positioning signal to a position detecting tablet, the position pointing device comprising: 
 a built-in power supply unit;    a plurality of signal transmitting units provided at a plurality of portions of said position pointing device; and    a power control unit for switching magnitude of transmission power of said signal transmitting units between at least two power levels.    
   
   
       36 . A position pointing device according to  claim 35 , wherein first and second signal transmitting units of said plurality of signal transmitting units are disposed at opposite end portions of said position pointing device to transmit a pen-point signal and an eraser signal, respectively.  
   
   
       37 . A position pointing device according to  claim 35 , further comprising a direction detecting unit for detecting the direction of said position pointing device relative to a position detecting tablet, wherein said power control unit is operable to increase, based on a detected result of the direction detecting unit, a magnitude of transmission power from whichever of said signal transmitting units is located on a side of said positioning pointing device nearer to the position detecting tablet, so that the magnitude of transmission power from said signal transmitting unit located on the side nearer to the position detecting tablet is greater than a magnitude of transmission power from whichever of said signal transmitting units is on the opposite side of said positioning pointing device.  
   
   
       38 . A position pointing device according to  claim 35 , wherein said control unit alternately switches said signal transmitting units between the energized state and the de-energized state.  
   
   
       39 . A position input system, comprising: 
 a position pointing device for transmitting positioning information signals, said position pointing device comprising a built-in power supply unit, a plurality of signal transmitting units provided at a plurality of portions of said position pointing device, and a power control unit for controlling transmission power of each of said plurality of signal transmitting units;    a position detecting tablet for receiving the positioning information signals from the position pointing device; and    a discriminating unit for discriminating the positioning information signals from said plurality of signal transmitting units.    
   
   
       40 . A position input system according to  claim 39 , wherein said discriminating unit comprises a first discriminating unit provided at a first end portion of said position pointing device to discriminate a pen-point signal, and wherein said position input system further comprises a second discriminating unit provided at a second end portion of said position pointing device to discriminate an eraser signal.  
   
   
       41 . A position input system according to  claim 39 , wherein said control unit alternately switches said signal transmitting units between the energized state and the de-energized state.  
   
   
       42 . A computer system, comprising: 
 a position pointing device for transmitting positioning signals, the position pointing device comprising a built-in power supply unit, a plurality of signal transmitting units provided at a plurality of portions of said position pointing device, and a power control unit for controlling transmission power of each of said plurality of signal transmitting units;    a position detecting tablet for receiving the positioning signals from the position pointing device;    a discriminating unit for discriminating the positioning signals from said plurality of signal transmitting units; and    a computer for processing the positioning signals from said position pointing device and discrimination information from said discriminating unit.    
   
   
       43 . A computer system according to  claim 42 , wherein said discriminating unit comprises a first discriminating unit provided at a first end portion of said position pointing device to discriminate a pen-point signal, and wherein said computer system further comprises a second discriminating unit provided at a second end portion of said position pointing device to discriminate an eraser signal.  
   
   
       44 . A computer system according to  claim 42 , wherein said control unit alternately switches said signal transmitting units between the energized state and the de-energized state.  
   
   
       45 . A method for charging a position pointing device, comprising the steps of: 
 providing a position pointing device for transmitting a positioning signal to a position detecting tablet, the position pointing device comprising a built-in power supply unit, a plurality of signal transmitting units provided at a plurality of portions of said position pointing device, and a control unit; and    switching said plurality of signal transmitting units between energized or de-energized states.