Coordinates input system

Abstract

Disclosed is a coordinates input system having a tablet constituting a coordinates input portion, a position designating device such as a stylus pen, and a position detection circuit adapted to drive said tablet and detect a position at which coordinates are input by said position designating device. The system comprises: an antenna coil disposed around a coordinates input range of said tablet; and a tuning circuit disposed in said position designating device and including a coil and a capacitor, wherein radio waves are generated by said antenna coil by application of an AC signal of a predetermined frequency thereto, and the status of said tuning circuit is discriminated by a signal of said antenna coil at the time when the transmission of said radio waves is suspended, thereby detecting the status of said position designating device. Hence, this coordinates input system is capable of detecting the status of the position designating device without connecting the position designating device and other circuits by means of a cord and without providing the position designating device with a conventionally employed complicated signal generating circuit, a battery, and the like.

What is claimed is: 
     
       1. A coordinates input system having a tablet constituting a coordinates input portion, a position designating device such as a stylus pen, and a position detection circuit adapted to drive said tablet and detect a position at which coordinates are input by said position designating device, said system comprising: an antenna coil disposed around a coordinates input range of said tablet; and   a tuning circuit disposed in said position designating device and including a coil and a capacitor,   wherein radio waves are generated by said antenna coil by application of an AC signal of a predetermined frequency thereto, and the status of said tuning circuit is discriminated by a signal of said antenna coil at the time when the transmission of said radio waves is suspended, thereby detecting the status of said position designating device.   
     
     
       2. A coordinates input system according to claim 1, wherein switching means for turning ON (or OFF) the connection between said coil and said capacitor is disposed in said tuning circuit, and when only a position of coordinates to be input is designated, said position designating device is used by turning said switching means ON (or OFF). 
     
     
       3. A coordinates input system according to claim 1, wherein said tablet is arranged such that a tablet body and said antenna coil are accommodated in a casing made of a non-metallic material, such as a synthetic resin. 
     
     
       4. A coordinates input system according to claim 1, further comprising a magnetism generator for designating a position. 
     
     
       5. A coordinates input system according to claim 1, wherein said antenna coil is arranged such that a conductive wire provided with an insulation coating, such as polyvinyl chloride, is disposed around said coordinates input range of said tablet. 
     
     
       6. A coordinates input system according to claim 1, wherein said tuning circuit includes a variable capacitor. 
     
     
       7. A coordinates input system having a tablet constituting a coordinates input portion, a position designating device such as a stylus pen, and a position detection circuit adapted to drive said tablet and detect a position at which coordinates are input by said position designating device, said system comprising: a plurality of tuning circuits disposed in said position designating device, each of said plurality of tuning circuits including a coil and a capacitor to constitute a set and being adapted to transmit radio waves with mutually equivalent tuning frequencies and different phases in response to an external signal;   switching means disposed in said position designating device and adapted to turn ON and OFF the connection between said coil and said capacitor of each of said tuning circuits; and   an antenna coil disposed around a coordinates input range of said tablet;   wherein radio waves are generated by said antenna coil when an AC signal of a frequency identical with that of said tuning frequency is intermittently applied to said antenna coil, and the status of the position and operation of said position designating device is detected when signals responded to by said tuning circuits during suspension of transmission of said radio waves are received by said antenna coil, and   the ON-OFF status of said switching means with respect to said tuning circuits is discriminated by means of input signals having mutually different phases with respect to output signals of said antenna coil.   
     
     
       8. A coordinates input system having a tablet constituting a coordinates input portion, a position designating device such as a stylus pen, and a position detection circuit adapted to drive said tablet and detect a position at which coordinates are input by said position designating device, said system comprising: a tuning circuit disposed in said position designating device, said tuning circuit including a set of a coil, a capacitor, and/or a resistor and being adapted to generate radio waves with mutually equivalent tuning frequencies and a change in the phase in response to an external signal by changing any of the values of said coil, said capacitor, and/or said resistor in correspondence with the status of use of said position designating device; and   an antenna coil disposed around a coordinates input range of said tablet;   wherein radio waves are generated by said antenna coil when an AC signal of a frequency identical with that of said tuning frequency is intermittently applied to said antenna coil, and the status of the position and operation of said position designating device is detected when signals responded to by said tuning circuit during suspension of transmission of said radio waves are received by said antenna coil, and   the status of use of said position designating device is discriminated by means of input signals having mutually different phases with respect to output signals of said antenna coil. .Iadd.   
     
     
       9.  An implement for designating one of plural characteristics thereof and a position thereof to a tablet including means for signalling indications of the implement characteristic and position comprising a cordless housing adapted to be manually held and manually moved proximate a surface of the tablet, the housing including:   a tuned circuit having no electric power supply connected to it, the tuned circuit including   reactance means including several reactances comprising an inductor and a capacitor, and   plural manually activated switches for connecting said several reactances together in different combinations to provide plural resonant frequencies for the tuned circuit in response to different ones of the plural manually activated switches being activated to signal a selected characteristic;   the housing being constructed so that waves having a magnetic component can be coupled without wires between a reactance of the tuned circuit and a structure outside of the housing. .Iaddend. .Iadd.   
     
     
       10.  The implement of claim 9 wherein the variable reactance includes a variable capacitor. .Iaddend. .Iadd. 
     
     
       11.  The implement of claim 9 wherein the switch means is activated in response to the implement region bearing against the tablet surface. .Iaddend. .Iadd.12. The implement of claim 9 wherein the switch means is 
     
     
        manually activated. .Iaddend. .Iadd.13.  An implement for signalling position thereof to position detecting coils for a tablet associated with a surface with which the implement is adapted to be moved comprising: a cordless housing adapted to be manually held and manually moved relative to the surface, the housing including: a region adapted to be moved relative to the surface,   a tuned circuit having no electric power supply connected to it, the tuned circuit including reactance means comprising an inductor, a capacitor and a variable reactance having at least several reactance values correlated with at least several pressure values of a region of the implement being urged against the surface;       the housing being constructed so that waves having a magnetic component can be coupled without wires between a reactance of the tuned circuit and a structure outside of the housing; and   means in proximity to the region for generating and supplying a magnetic field to the position detecting coils for the implement. .Iaddend.   
     
     
        .Iadd.  .  The implement of claim 13 wherein a fixed capacitor is connected in circuit with said variable reactance. .Iaddend. .Iadd.15. The implement of claim 13 wherein the field generating and supplying means comprises a magnet. .Iaddend. .Iadd.16. The implement of claim 13 wherein 
     
     
        the housing is formed as a writing pen. .Iaddend. .Iadd.17.  In combination, a tablet including position detecting coils arranged in two coordinate directions,   a manually held implement having a region adapted to be moved relative to a surface of the tablet associated with the position detecting coils, the implement including: a cordless housing adapted to be manually held and manually moved relative to the surface, the housing including:   a tuned circuit having no electric power supply connected to it, the tuned circuit including   an inductor and a capacitor, and   a variable reactance having a reactance value responsive to the pressure exerted by said region against the surface;   the housing being constructed so that waves having magnetic components can be coupled without wires between a reactance of the tuned circuit and a structure outside of the housing,   means in proximity to the region for generating and supplying a magnetic field to the position detecting coils for the implement; and     means responsive to the magnetic field coupled between the implement and the coils for signalling the position of the implement relative to the two coordinate directions, the signalling means responding to variations of the variable reactance to indicate the width of a line as a function of   
     
     
        implement position on the surface. .Iaddend. .Iadd.18.  The combination of claim 17 wherein the housing is formed as a writing pen. .Iaddend. 
     
     
        .Iadd.  .  The combination of claim 17 wherein the variable reactance has at least several values correlated with at least several of said exerted pressures, the signalling means responding to the at least several values of the reactance to indicate which of the at least several pressures is 
     
     
        being exerted. .Iaddend. .Iadd.20.  In combination, a tablet including position detecting coils arranged in two coordinate directions, a markable surface superposed with said tablet in said two coordinate directions,   a manually held implement for changing markings on the display surface including an inductor and a capacitor, and   a switch activated while a region of the implement is proximate the surface for connecting the capacitor and inductor in circuit with each other so that the tuned circuit has a predetermined resonant frequency;   the housing being constructed so that waves having a magnetic component can be coupled without wires between a reactance of the tuned circuit and a structure outside of the housing,   means in proximity to the region for generating and supplying a magnetic field to the position detecting coils for the implement, the position detecting coils being in proximity to and associated with the display, and   means responsive to the magnetic field coupled between the implement and the coils while the switch is activated for signalling the position of the     
     
     
        implement relative to the two coordinate directions. .Iaddend. .Iadd.21. The combination of claim 20 wherein the tuned circuit includes a variable reactance having a reactance value responsive to the pressure exerted by said region against the surface, wherein the signalling means responds to variations of the variable reactance to indicate the pressure of the implement on the surface as a function of implement position on the 
     
     
        surface. .Iaddend. .Iadd.22.  The combination of claim 21 wherein the variable reactance has at least several values responsive to at least several pressures exerted by said region against the surface. .Iaddend. 
     
     
        .Iadd.23.  The combination of claim 20 wherein the housing is formed as a writing pen. .Iaddend. .Iadd.24. The combination of claim 20 wherein said implement has different characteristics associated with it, said housing further including: (a) a plurality of said tuned circuits, each of said tuned circuits having reactances with different values, and   (b) switch means for selectively connecting the reactances of the different plural tuned circuits in circuit with each other as a function of the   
     
     
        selected characteristic of the implement. .Iaddend. .Iadd.25.  The combination of claim 20 wherein the switch is activated in response to the region being urged against the surface. .Iaddend. .Iadd.26. A method of identifying which one of plural characteristics is possessed by an object in proximity to a coil and determining the location of the object, each of the characteristics being associated with different valued reactances of a tuned circuit on the object so that different tuned circuits are associated with different characteristics, the different valued reactances causing the tuned circuit to couple waves including a magnetic component and having different angular modulations with the coil, the method comprising the steps of supplying the coil with AC energy including a predetermined frequency, coupling the energy from the coil to the tuned circuit on the object, the tuned circuit on the object interacting with the energy coupled with it as a function of the value of the reactances of the tuned circuit so that there is a different angular modulation of the waves coupled between the coil and the tuned circuit as a function of the characteristics associated with the different tuned circuits and the predetermined frequency, detecting the angular modulation of the waves coupled between the coil and the tuned circuit to identify the characteristic of the object, and detecting the position of the object by coupling energy between the object and a region including the coil, said region including a two dimensional array of detectors that interact with 
     
     
        the coupled energy. .Iaddend. .Iadd.27.  The method of claim 26 wherein the energy at the predetermined frequency is coupled from the coil to the tuned circuit on the object during a first interval and the wave having angular modulation is coupled from the tuned circuit on the object to the coil during a second interval while the energy at the predetermined frequency is not coupled to the coil. .Iaddend. .Iadd.28. The method of claim 27 wherein the angular modulation is phase modulation and the detecting step includes detecting the phase of the phase modulation of the electric wave coupled to the coil during the second interval. .Iaddend. 
     
     
        .Iadd.29.  A method of identifying a characteristic of an implement from one of plural different characteristics, the implement including: (a) means for modifying markings on a display surface while a region of the implement is proximate the display surface and (b) a tuned circuit with components selectively connected to each other to have a predetermined resonant frequency while the region of the implement is proximate the surface, the identified characteristic being associated with a tuned circuit having one of plural reactance combinations, each of said plural different characteristics being associated with one of said plural reactance combinations, the method comprising modifying the markings on the display surface by moving the region proximate the display surface while the reactances are connected to each other in one of said reactance combinations to provide a tuned circuit having the resonant frequency,   determining which one of the reactance combinations the tuned circuit has by coupling a wave having a magnetic component at the resonant frequency between a coil and the tuned circuit, the tuned circuit interacting with the wave coupled with it as a function of the value of the reactances of the tuned circuit so that there is different angular modulation of the wave coupled between the coil and the tuned circuit is a function of the characteristics associated with the different tuned circuits and the predetermined frequency, and   detecting the angular modulation of the waves coupled between the coil and the tuned circuit to identify the characteristic of the implement being     
     
     
        moved proximate the display surface. .Iaddend. .Iadd.30.  The method of claim 29 wherein the wave is coupled from a source of the frequency to the tuned circuit. .Iaddend. .Iadd.31. The method of claim 30 wherein the wave is coupled from the source to the tuned circuit during a first interval and the angle modulated wave is coupled from the tuned circuit to a detector for the predetermined frequency during a second interval. .Iaddend. .Iadd.32. The method of claim 31 further including the step of detecting the position of the object by coupling energy between the object and a region including the surface, said region including a two dimensional array of detectors that interact with the coupled energy. 
     
     
        .Iaddend. .Iadd.33.  The method of claim 29 further including the step of detecting the position of the object by coupling energy between the object and a region including the surface, said region including a two dimensional array of detectors that interact with the coupled energy. 
     
     
        .Iaddend. .Iadd.34.  In combination, a coil, an object having one of plural different predetermined characteristics, the object being adapted to be selectively in proximity to the coil, the object including a tuned circuit having a predetermined resonant frequency, different one of said characteristics being associated with different combinations of reactances of the tuned circuit, means for supplying AC energy at the resonant frequency to the coil, the tuned circuit on the object in proximity to the coil interacting with a wave including a magnetic component resulting from the energy coupled to the coil as a function of the value of the reactances of the tuned circuit so that there is different angular modulation of the waves coupled between the coil and the turned circuit as a function of the characteristics associated with the different tuned circuits and the predetermined frequency, means for detecting the angular modulation of the waves coupled between the coil and the tuned circuit to identify the characteristic of the object, and means for detecting the position of the identified object, said position detecting means coupling energy between the object and a region including the coil, said region including a two-dimensional array of detectors for interacting with the 
     
     
        coupled energy. .Iaddend. .Iadd.35.  The combination of claim 34 wherein the modulation is detected by supplying the coil during a first interval with the AC energy at the predetermined frequency, the means for detecting being activated to be responsive to energy coupled back to the coil from the tuned circuit during a second interval while the coil is not supplied with the AC energy at the one predetermined frequency. .Iaddend. 
     
     
        .Iadd.     The combination of claim 34 wherein the object is in the form 
     
     
        of a pen. .Iaddend. .Iadd.37.  The combination of claim 34 wherein said object further includes: (a) a plurality of said tuned circuits, each of said tuned circuits having reactances with different values, and   (b) switch means for selectively connecting the reactances of the different plural tuned circuits in circuit with each other as a function of a selected characteristic of the object. .Iaddend. .Iadd.38. The combination of claim 34 further including a surface in proximity to the coil, the object including   a cordless housing adapted to be manually held and manually moved relative to the tablet, the housing including:   means positioned in a region thereof adapted to be moved proximate the tablet,   the tuned circuit having no electric power supply connected to it, the tuned circuit including   an inductor and a capacitor, and   a switch activated in response to the region being proximate the tablet for connecting the capacitor and inductor in circuit with each other so that the tuned circuit has a predetermined resonant frequency;   the housing being constructed so that waves having magnetic components can be coupled without wires between a reactance of the tuned circuit and a   
     
     
        structure outside of the housing. .Iaddend. .Iadd.39.  The combination of claim 38 wherein the switch is activated in response to the region being urged against the surface. .Iaddend. .Iadd.40. Apparatus for determining which one of plural different characteristics is possessed by an object in a region and the position of the object, different ones of said characteristics being associated with different tuned circuit combinations of reactances, each of said tuned circuit combinations having a different resonant frequency, comprising a coil in the region, means for supplying AC energy at the resonant frequency to the coil, the tuned circuit on said object in proximity to the coil interacting with an electric wave resulting from the energy coupled to the coil as a function of the value of the reactances of the tuned circuit so that there is a different angular modulation of the waves coupled between the coil and the tuned circuit as a function of the characteristics associated with the different tuned circuits and the frequency of the supplied AC energy, means for detecting the angular modulation of the wave coupled between the coil and the tuned circuit to identify the characteristic of the object, and means for detecting the position of the identified object, said position detecting means coupling energy between the object and a region including the coil, said region including a two-dimensional array of detectors for 
     
     
        interacting with the coupled energy. .Iaddend. .Iadd.41.  The apparatus of claim 40 wherein the modulation is detected by supplying the coil during a first interval with the AC energy at the predetermined frequency, the means for detecting being activated to be responsive to energy coupled back to the coil from the tuned circuit during a second interval while the coil is not supplied with the AC energy at the one predetermined frequency. .Iaddend. .Iadd.42. Apparatus for determining the position of and which one of plural characteristics is included in an implement positioned proximate a detecting surface, the implement including a tuned circuit having a predetermined resonant frequency identifying the characteristic, different tuned circuits with different combinations of reactances being associated with the different characteristics, comprising a tablet in the region for coupling energy to the implement,   a coil associated with the tablet for supplying AC energy at the resonant frequency to the tuned circuit, the tuned circuit on the implement causing angle modulation of the current flowing in the coil, the angle modulation being different for different ones of said tuned circuits to provide an identification of the different characteristics, and   means for sensing the angle modulation of the current flowing in the coil and responding to the sensed angle modulation for indicating the identified characteristic associated with the tuned circuit and responsive to energy coupled between the tablet and the implement for indicating the position of the implement on the tablet. .Iaddend. .Iadd.43. The apparatus of claim 42 wherein the angle modulation is detected by supplying the coil during a first interval with the AC energy at the predetermined frequency, the means for sensing being activated to be responsive to energy coupled back to the coil from the tuned circuit during a second interval while the coil is not supplied with the AC energy at the predetermined frequency. .Iaddend. .Iadd.44. In combination, a position sensing tablet, a coil associated with the tablet, an implement having one of plural characteristics adapted to be selectively placed proximate the tablet, the tablet and the implement having structures for coupling energy between them, the implement including a tuned circuit having a predetermined resonant frequency, different tuned circuits with different combinations of reactances associated with the different characteristics, means for supplying AC energy at the predetermined resonant frequency to the tuned circuit, the tuned circuit on the implement causing angle modulation of the current flowing in the coil, the angle modulation being different for different ones of said tuned circuits to provide an identification of the different characteristics, and   means for sensing the angle modulation of the current flowing in the coil and responding to the sensed angle modulation for indicating the identified characteristic associated with the tuned circuit and responsive to energy coupled between the tablet and the implement for indicating the position of the implement on the tablet. .Iaddend. .Iadd.45. The combination of claim 44 wherein the change is detected by supplying the coil during a first interval with the AC energy at the predetermined frequency, the means for sensing being activated to be responsive to energy coupled back to the coil from the tuned circuit during a second interval while the coil is not supplied with the AC energy at the one   
     
     
        predetermined frequency. .Iaddend. .Iadd.46.  A method of determining the position of an implement on a tablet, the implement including a tuned circuit with a predetermined resonant frequency and a variable reactance connected in circuit with the tuned circuit, the variable reactance having at least several values that change as a function of at least several pressures exerted by the implement on a surface proximate the tablet, the tablet including a coil, comprising the steps of: exciting the coil with AC energy having approximately the same frequency as the resonant frequency, the tuned circuit interacting with the AC energy to change the AC current flowing in the coil as a function of the at least several exerted pressures, detecting the position of the implement on the tablet in response to an energy field coupled between the tablet and the implement, and responding to the AC current flowing in the coil and the detected implement position to indicate the value of the at least several exerted pressures at the detected implement positions on the surface.   
     
     
        .Iaddend. .Iadd.47.  The method of claim 46 wherein the exerted pressure is indicated by detecting angle modulation imposed on the current flowing in the coil in response to the interaction between the AC energy and the tuned circuit. .Iaddend. .Iadd.48. The method of claim 46 wherein the exerted pressure is indicated by detecting phase modulation imposed on the current flowing in the coil in response to the interaction between the AC energy and the tuned circuit. .Iaddend. .Iadd.49. The method of claim 46 wherein the coil is excited during a first interval with the AC energy at the predetermined frequency, and the indication is derived by responding to energy coupled back to the coil from the tuned circuit during a second interval while the coil is not excited by the AC energy at the 
     
     
        predetermined frequency. .Iaddend. .Iadd.50.  Apparatus for signalling the width of a trace resulting from an implement being moved relative to and against a surface, the implement including a region adapted to be moved across and against the surface and a tuned circuit having a resonant frequency, the circuit including a variable reactance controlled in response to the width of a trace produced in response to the pressure of the region on the surface, the apparatus including a coil in proximity to the surface, means for energizing the coil with an AC wave having substantially the same frequency as the resonant frequency, the tuned circuit interacting with the AC wave to angle modulate the AC wave as a function of the width of the trace, and means for detecting the angle modulation of the angle modulated AC wave to indicate trace width. 
     
     
        .Iaddend. .Iadd.51.  The apparatus of claim 50 wherein the means for indicating exerted pressure includes means for detecting angle modulation imposed on the current flowing in the coil in response to the interaction between the AC energy and the tuned circuit. .Iaddend. .Iadd.52. The apparatus of claim 50 wherein the means for indicating exerted pressure includes means for detecting phase modulation imposed on the current flowing in the coil in response to the interaction between the AC energy 
     
     
        and the tuned circuit. .Iaddend. .Iadd.53.  The apparatus of claim 50 wherein the angle modulation is detected with a detector responsive to the angle modulation of angle modulated current flowing in the coil in response to the interaction between the AC wave and the tuned circuit. .Iaddend. .Iadd.54. The apparatus of claim 53 wherein the coil is energized with the resonant frequency during a first interval and the detector is responsive to the angle modulated current during a second interval while the coil is not energized with the resonant frequency. 
     
     
        .Iaddend. .Iadd.55.  The implement of claim 50 wherein the reactance is responsive to the pressure exerted by the region on the surface so that the modulation is a function of the pressure exerted by the region against the surface. .Iaddend. .Iadd.56. The apparatus of claim 50 wherein the variable reactance has at least several values corresponding to at least several trace widths so that the angle modulation has at least several values, the means for detecting indicating the value of the at least 
     
     
        several angle modulated values. .Iaddend. .Iadd.57.  A method of signalling the width of a trace resulting from an implement being moved relative to and against a surface, the implement including a region adapted to be moved across and against the surface and a tuned circuit having a resonant frequency, the circuit including a variable reactance controlled in response to the width of a trace produced by the region on the surface, comprising energizing a coil in proximity to the surface with an AC wave having substantially the same frequency as the resonant frequency, the tuned circuit interacting with the AC wave to angle modulate the AC wave as a function of the width of the trace resulting from the region being pressed on the surface, and detecting the angle modulation of the angle modulated AC wave to indicate trace width. 
     
     
        .Iaddend. .Iadd.58.  The method of claim 57 wherein the angle modulation is detected by detecting the angle modulated current flowing in the coil in response to the interaction between the AC wave and the tuned circuit. .Iaddend. .Iadd.59. The method of claim 58 wherein the coil is energized with the resonant frequency during a first interval and the angle modulation of the angle modulated current is detected during a second interval while the coil is not energized with the resonant 
     
     
        frequency..Iaddend. .Iadd.60.  The method of claim 57 wherein the reactance is responsive to the pressure exerted by the region on the surface so that the modulation is a function of the pressure exerted by the region against the surface. .Iaddend. .Iadd.61. In combination, an implement including a region adapted to be moved across a surface and a tuned circuit having a resonant frequency, the circuit including a variable reactance controlled in response to the width of a trace resulting from the region being on the surface,   apparatus for signalling the width of the trace resulting from the implement being on the surface, the apparatus including: a coil in proximity to the surface,   means for energizing the coil with an AC wave having substantially the same frequency as the resonant frequency, the tuned circuit interacting with the AC wave to angle modulate the AC wave as a function of the width of the trace produced by the region on the surface, and   means for detecting the angle modulation of the angle modulated AC wave to     
     
     
        indicate line width. .Iaddend. .Iadd.62.  The combination of claim 61 wherein the angle modulation is detected with a detector responsive to the angle modulation of angle modulated current flowing in the coil in response to the interaction between the AC wave and the tuned circuit. .Iaddend. .Iadd.63. The combination of claim 62 wherein the coil is energized with the resonant frequency during a first interval and the detector is responsive to the angle modulated current during a second interval while the coil is not energized with the resonant frequency. 
     
     
        .Iaddend. .Iadd.64.  The combination of claim 61 further including means for indicating the position of the implement and the accompanying detected pressure on the surface. .Iaddend. .Iadd.65. The implement of claim 61 wherein the reactance is responsive to the pressure exerted by the region on the surface so that the modulation is a function of the pressure 
     
     
        exerted by the region against the surface. .Iaddend. .Iadd.66.  In combination, a coil, an object having one of plural different predetermined characteristics, the object being adapted to be selectively in proximity to the coil, the object including a tuned circuit having a predetermined resonant frequency, different ones of said characteristics being associated with different combinations of reactances of the tuned circuit, means for supplying AC energy at the resonant frequency to the coil, the tuned circuit on the object in proximity to the coil interacting with a wave including a magnetic component resulting from the energy coupled to the coil as a function of the value of the reactances of the tuned circuit so that there is different angular modulation of the waves coupled between the coil and the tuned circuit as a function of the characteristics associated with the different tuned circuits and the predetermined frequency, and means for detecting the angular modulation of the waves coupled between the coil and the tuned circuit to identify the characteristic of the object, the object further including means for generating and supplying a field including a magnetic component to a tablet including two-coordinate position detecting coils for the object, the position detecting coils responding to the field to signal the object 
     
     
        position. .Iaddend. .Iadd.67.  In combination, a coil, an object in the form of a pen having one of plural different predetermined characteristics, the object being adapted to be selectively in proximity to the coil, the object including a tuned circuit having a predetermined resonant frequency, different ones of said characteristics being associated with different combinations of reactances of the tuned circuit, means for supplying AC energy at the resonant frequency to the coil, the tuned circuit on the object in proximity to the coil interacting with a wave including a magnetic component resulting from the energy coupled to the coil as a function of the value of the reactances of the tuned circuit so that there is different angular modulation of the waves coupled between the coil and the tuned circuit as a function of the characteristics associated with the different tuned circuits and the predetermined frequency, and means for detecting the angular modulation of the waves coupled between the coil and the tuned circuit to identify the characteristic of the object. .Iaddend. .Iadd.68. In combination, a position detecting tablet including a coil, an object having one of plural different predetermined characteristics, the object being adapted to be selectively in proximity to the coil, the object including a tuned circuit having a predetermined resonant frequency, different ones of said characteristics being associated with different combinations of reactances of the tuned circuit, means for supplying AC energy at the resonant frequency to the coil, the tuned circuit on the object in proximity to the coil interacting with a wave including a magnetic component resulting from the energy coupled to the coil as a function of the value of the reactances of the tuned circuit so that there is different angular modulation of the waves coupled between the coil and the tuned circuit as a function of the characteristics associated with the different tuned circuits and the predetermined frequency, and means for detecting the angular modulation of the waves coupled between the coil and the tuned circuit to identify the characteristic of the object, the object including   a cordless housing adapted to be manually held and manually moved relative to the tablet, the housing including:   means positioned in a region thereof adapted to be moved proximate the tablet,   the tuned circuit having no electric power supply connected to it, the tuned circuit including an inductor and a capacitor, and   a switch activated in response to the region being proximate the tablet for connecting the capacitor and inductor in circuit with each other so that the tuned circuit has a predetermined resonant frequency;     the housing being constructed so that waves having magnetic components can be coupled without wires between a reactance of the tuned circuit and a structure outside of the housing. .Iaddend. .Iadd.69. In combination, a coil, an object having one of plural different predetermined characteristics, the object being adapted to be selectively in proximity to the coil, the object including a tuned circuit having a predetermined resonant frequency, different ones of said characteristics being associated with different combinations of reactances of the tuned circuit, means for supplying AC energy at the resonant frequency to the coil, the tuned circuit on the object in proximity to the coil interacting with a wave including a magnetic component resulting from the energy coupled to the coil as a function of the value of the reactances of the tuned circuit so that there is different angular modulation of the waves coupled between the coil and the tuned circuit as a function of the characteristics associated with the different tuned circuits and the predetermined frequency, and means for detecting the angular modulation of the waves coupled between the coil and the tuned circuit to identify the characteristic of the object, the object further including means for generating and supplying a field including a magnetic component to a tablet including two-coordinate position detecting coils for the object, the position detecting coils responding to the field to signal the object position. .Iaddend. .Iadd.70. A manually held implement adapted to be urged against a surface comprising:   a cordless housing shaped as a writing pen adapted to be manually held and manually moved on the surface, the housing including: a region adapted to be moved across the surface,   a tuned circuit having no electric power supply connected to it, the tuned circuit including a variable pressure responsive reactance coupled to the region so that the width of a trace resulting from the region being on the surface is determined by the value of the variable reactance, the housing being constructed so that waves having a magnetic component are coupled without wires between a reactance of the tuned circuit and a structure outside of the housing. .Iaddend. .Iadd.71. A signalling method comprising moving a region of an implement including a tuned circuit having a resonant frequency against a surface, varying the value of a reactance of the tuned circuit in response to the pressure exerted by the region on the surface as the implement is being moved relative to the surface, energizing a coil in proximity to the surface with an AC wave having substantially the same frequency as the resonant frequency, the tuned circuit interacting with the AC wave to angle modulate the AC wave as a function of the pressure exerted by the region on the surface, and detecting the angle modulation of the angle modulated AC wave to indicate the exerted pressure. .Iaddend. .Iadd.72. The method of claim 71 wherein the detected exerted pressure is commensurate with the width of a trace resulting from the region being pressed against the surface. .Iaddend. .Iadd.73. The method of claim 72 further including detecting the position of the region on the surface accompanying the detected trace width. .Iaddend. .Iadd.74. The method of claim 71 further including detecting the position of the region on the       
     
     
        surface accompanying the detected exerted pressure. .Iaddend. .Iadd.75.  A method of detecting the status of an implement in a coordinate input device comprising: emitting a wave having a magnetic component from an emitting means of a position detecting tablet,   responding to the emitted wave to excite a tuned circuit in a position designating implement, the tuned circuit when excited emitting a wave having a frequency determined by the resonant frequency of the tuned circuit,   receiving a wave having a magnetic component in a wave receiving means of said tablet, and   deriving an indication of the status of said position designating implement in response to the received wave being the wave emitted by the tuned circuit, said waves emitted from and received by the tablet being emitted   
     
     
        and received in the same loop coil. .Iaddend. .Iadd.76.  The method of claim 75 wherein said waves emitted from and received by the tablet are 
     
     
        alternately emitted and received. .Iaddend. .Iadd.77.  A method of detecting a pen-down status of a stylus in a coordinate input device comprising: emitting a wave having a magnetic component from an emitting means of a position detecting table,   responding to the emitted wave to excite a tuned circuit in a position designating implement, the tuned circuit when excited emitting a wave having a frequency determined by the resonant frequency of the tuned circuit,   receiving a wave having a magnetic component in a wave receiving means of said tablet, and   deriving an indication that the stylus is in a pen-down status in response to the received wave being the wave emitted by the tuned circuit, said waves emitted from and received by the tablet being emitted and received   
     
     
        in the same loop coil. .Iaddend. .Iadd.78.  The method of claim 77 wherein said waves emitted from and received by the tablet are alternately emitted and received. .Iaddend. .Iadd.79. A method of determining which of plural switches is being operated in a position designating implement of a coordinate input device, each of the switches being associated with a different resonant frequency of a tuned circuit means, comprising: emitting a wave having a magnetic component from an emitting means of a position detecting tablet,   responding to the emitted wave to excite the tuned circuit means as a function of which of the switches is operated by handling, the resonant circuit when excited emitting a wave having a frequency determined by the activated switch,   receiving the wave emitted by the tuned circuit means in a wave receiving means of said tablet, and   detecting which resonant circuit emits the wave received by said wave receiving means to determined which switch is being operated. .Iaddend. .Iadd.80. The method of claim 79 wherein said waves emitted from and received by the tablet are emitted and received in the same loop coil.   
     
     
        .Iaddend. .Iadd.81.  The method of claim 80 wherein said waves emitted from and received by the tablet are alternately emitted and received. .Iaddend. .Iadd.82. The method of claim 79 wherein said waves emitted from and received by the tablet are alternately emitted and received. .Iaddend. 
     
     
        .Iadd.83.  An implement having different characteristics associated therewith for designating one of the characteristics and a position to be detected by a tablet including means for signalling indications of the implement characteristic and position comprising a cordless housing adapted to be manually held and manually moved proximate a surface of the tablet, the housing including:   a plurality of tuned circuits having no electric power supply connected to them, the plurality of tuned circuits including   an inductive and a capacitive reactance, each of said tuned circuits having reactances with different values,   a switch adapted to be activated while a region of the implement moves proximate the surface for connecting the capacitor and inductor in circuit with each other so that the tuned circuit has a predetermined resonant frequency, and   switch means for selectively connecting the reactances of the different plural tuned circuits in circuit with each other as a function of the selected characteristic of the implement;   the housing being constructed so that waves having a magnetic component can be coupled without wires between a reactance of the tuned circuit and structure outside of the housing. .Iaddend. .Iadd.84. An implement having different characteristics associated therewith for signalling one of the characteristics and position thereof to position detecting coils for a tablet associated with a surface with which the implement is adapted to be moved comprising:   a cordless housing adapted to be manually held and manually moved relative to the surface, the housing including:   a region adapted to be moved relative to the surface,   a plurality of tuned circuits having no electric power supply connected to them, the plurality of tuned circuits including   an inductive and capacitive reactance, each of said tuned circuits having a reactance with a different value,   a switch adapted to be activated while a region of the implement moves proximate the surface for connecting the capacitor and inductor in circuit with each other so that the tuned circuit has a predetermined resonant frequency, switch means for selectively connecting the reactances of the different plural tuned circuits in circuit with each other as a function of the selected characteristic of the implement:   the housing being constructed so that waves having a magnetic component can be coupled without wires between a reactance of the tuned circuit and a structure outside of the housing, and   means in proximity to the region for generating and supplying a magnetic field to the position detecting coils for the implement. .Iaddend.   
     
     
        .Iadd.  .  In combination, a tablet including position detecting coils arranged in two coordinate directions,   a manually held implement having different characteristics associated with it and a region adapted to be moved relative to a surface of the tablet associated with the position detecting coils, the implement including:   a cordless housing adapted to be manually held and manually moved relative to the surface, the housing including:   a plurality of tuned circuits having no electric power supply connected to them, the tuned circuits including   an inductive and capacitive reactance,   each of said tuned circuits having reactances with different values, and   switch means for selectively connecting the reactances of the different plural tuned circuits in circuit with each other to provide different resonant frequencies of the tuned circuits as a function of the selected characteristic of the implement;   the housing being constructed so that waves having magnetic components can be coupled without wires between a reactance of the tuned circuit and a structure outside of the housing;   means in proximity to the region for generating and supplying a magnetic field to the position detecting coils for the implement; and   means responsive to the magnetic field coupled between the implement and the coils for signalling the characteristic of the implement and the position of the implement relative to the two coordinate directions.   
     
     
        .Iaddend. .Iadd.86.  A method of detecting the status of an implement in a coordinate input device comprising: emitting a wave having a magnetic component from an emitting means of a position detecting tablet,   responding to the emitted wave to excite a tuned circuit in a position designating implement, the tuned circuit when excited emitting a wave having a frequency determined by the resonant frequency of the tuned circuit,   receiving a wave having a magnetic component in a wave receiving means of said tablet, and   deriving an indication of the status of said position designating implement in response to the received wave being the wave emitted by the tuned circuit, said waves emitted from said received by the tablet being   
     
     
        alternately emitted and received. .Iaddend. .Iadd.87.  A method of detecting a pen-down status of a stylus in a coordinate input device comprising: emitting a wave having a magnetic component from an emitting means of a position detecting tablet,   responding to the emitted wave to excite a tuned circuit in a position designating implement, the tuned circuit when excited emitting a wave having a frequency determined by the resonant frequency of the tuned circuit,   receiving a wave having a magnetic component in a wave receiving means of said tablet, and   deriving an indication that the stylus is in a pen-down status in response to the received wave being the wave emitted by the tuned circuit, said waves emitted from and received by the tablet being alternately emitted and received. .Iaddend. .Iadd.88. A characteristic and position designating implement in a coordinate input device, comprising:   a housing shaped to be manually held,   plural tuned circuits each having a different predetermined resonant frequency associated with a different characteristic of the implement and a separate switch, said circuits being carried by said housing, said tuned circuits being excited by a wave including a magnetic component as emitted from a tablet and coupling a wave including a magnetic component to said tablet. .Iaddend. .Iadd.89. A manually held implement adapted to be urged against a surface comprising:   a cordless housing adapted to be manually held and manually moved on the surface, the housing including:   a region adapted to be moved across the surface,   a tuned circuit having no electric power supply connected to it, the tuned circuit including   a variable reactance coupled to the region so that at least several pressures produced by the region on the surface control the at least several values of the variable reactance, the housing being constructed so that waves having a magnetic component can be coupled without wires between a reactance of the tuned circuit and a structure outside of the housing. .Iaddend. .Iadd.90. A method of signalling the width of a trace resulting from an implement being moved relative to and against a surface, the implement including a region adapted to be moved across and against the surface and a tuned circuit having a resonant frequency, the circuit including a variable reactance having at least several values controlled in response to at least several pressures produced by the region on the surface, comprising energizing a coil in proximity to the surface with an AC wave having substantially the same frequency as the resonant frequency, the tuned circuit interacting with the AC wave to angle modulate the AC wave as a function of the at least several pressures produced by the region on the surface, and detecting the angle modulation of the angle modulated AC wave to indicate which of the at least several pressures is being exerted on the surface and the trace width. .Iaddend. .Iadd.91. In combination,   an implement including a region adapted to be moved across a surface and a tuned circuit having a resonant frequency, the circuit including a variable reactance having at least several values controlled in response to at least several pressures produced by the region on the surface,   apparatus for signalling the at least several pressures produced by the implement on the surface, the apparatus including:   a coil in proximity to the surface,   means for energizing the coil with an AC wave having substantially the same frequency as the resonant frequency, the tuned circuit interacting with the AC wave to angle modulate the AC wave to at least several values as a function of the at least several pressures produced by the region on the surface, and   means for detecting the value of the at least several values of the angle modulation of the angle modulated AC wave to indicate which of the at least several pressures is being exerted on the surface. .Iaddend. .Iadd.92. A position designating implement in a coordinate input device, comprising:   a housing,   a tuned circuit carried by the housing, the circuit having a resonant frequency varied in response to handling, said tuned circuit being excited by a wave having a magnetic component as emitted from a tablet to couple a wave having a magnetic component to said tablet, the resonant frequency being varied to at least several values by at least several pressures of a structure in the housing on the tablet surface. .Iaddend.