Surface position location system and method
First Claim
1. An electrographic sensor unit for use in determining the position of a selected point, which comprises:
- a layer of a conductive material having an electrical resistivity and a surface;
three spaced apart contact points electrically interconnected with said layer of conductive material;
a processor connected to said three spaced apart contact points and disposed to selectively apply a signal to each of said three spaced apart contact points; and
a probe assembly, including a stylus, coupled to said processor, said stylus disposed to be positioned by a user in vicinity of a user selected point on said surface of said layer and to receive signals from said layer when said three spaced apart contact points have signals selectively applied thereto;
wherein said position of said stylus relative to said surface of said layer is determinable by said processor from signals received from said stylus each in relation to a similar excitation of two different pairs of said three spaced apart contact points under control of said processor.
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Accused Products
Abstract
Electrographic sensor and method for position determination of a selected position thereon. Sensor includes a conductive material layer having electrical resistivity and a surface, at least three spaced apart contact points electrically interconnected with the layer, a processor connected to the contacts disposed to selectively apply a signal to each contact, and a probe assembly that includes either a stylus coupled to the processor with the stylus disposed to be positioned by a user in vicinity of the selected position on the layer, or a flexible layer with a user'"'"'s finger selecting that position on the flexible layer to receive signals from the layer when the contact points have signals selectively applied. The selected position is determined by the processor from signals received from the stylus, or flexible layer, each in relation to a similar excitation of different pairs of the contacts. The conductive layer of either two or three dimensions including a closed three dimensional shape. With multiple layers the processor is able to discern on which layer the user selected position is located. Correction of the calculated coordinates of the selected position for variations in contact resistance of the contact points. A non-conductive skin having graphics printed thereon, i.e. a map, can be placed over the layer and the processor further converts the calculated coordinates of the selected position to coordinates relative to the graphical information printed on the skin, and electronically (audio or visual) present information to the user relative to the graphical location selected.
265 Citations
73 Claims
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1. An electrographic sensor unit for use in determining the position of a selected point, which comprises:
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a layer of a conductive material having an electrical resistivity and a surface; three spaced apart contact points electrically interconnected with said layer of conductive material; a processor connected to said three spaced apart contact points and disposed to selectively apply a signal to each of said three spaced apart contact points; and a probe assembly, including a stylus, coupled to said processor, said stylus disposed to be positioned by a user in vicinity of a user selected point on said surface of said layer and to receive signals from said layer when said three spaced apart contact points have signals selectively applied thereto; wherein said position of said stylus relative to said surface of said layer is determinable by said processor from signals received from said stylus each in relation to a similar excitation of two different pairs of said three spaced apart contact points under control of said processor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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27. The electrographic sensor unit of claim 1 wherein said position of said stylus is determined by said processor causing selected signals to be applied to various combinations of said three spaced apart contact points and a measured signal received by said stylus in response to each application of signals that are used by said processor to calculate the position to which said stylus is pointed by the user:
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a first measurement is made by open circuiting each of said three spaced apart contact points and measuring an offset signal, SignalOFFSET, with said stylus; a second measurement is made by applying the same signal to each of said three spaced apart contact points and measuring a full signal, SignalFULL, with said stylus; a third measurement is made by applying a signal between a first two of said three spaced apart contact points with the other contact point left unconnected, the value of the signal applied between said first two contact points has a fixed relationship to the value of the signal used to make said second measurement, and measuring a raw signal between said first two contact points, SignalRAW-FIRST-TWO, with said stylus; a fourth measurement is made by applying a signal between a second two of said three spaced apart contact points with the other contact point left unconnected, the value of the signal applied between said second two contact points has a fixed relationship to the value of the signal used to make said second measurement, and measuring a raw signal between said second two contact points, SignalRAW-SECOND-TWO, with said stylus; and calculating the relative position to which the stylus is pointed by the user relative to said first two contact points and said second two contact points using the following equations, the values from those equations being coordinates on an equipotential map of the user selected point to which the user is pointing said stylus with the axes of those coordinates being imaginary lines between each of said first two contact points and said second two contact points;
space="preserve" listing-type="equation">P.sub.FIRST-TWO =(Signal.sub.RAW-FIRST-TWO -Signal.sub.OFFSET)/(Signal.sub.FULL -Signal.sub.OFFSET);and
space="preserve" listing-type="equation">P.sub.SECOND-TWO =(Signal.sub.RAW-SECOND-TWO -Signal.sub.OFFSET)/(Signal.sub.FULL -Signal.sub.OFFSET).
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28. The electrographic sensor unit of claim 27 wherein:
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a predetermined signal map of said layer of conductive material is prestored in said processor; and said calculated values of PFIRST-TWO and PSECOND-TWO are used by said processor in conjunction with said signal map to translate said calculated values into a physical position on said surface to which said user is pointing said stylus.
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29. The electrographic sensor unit of claim 1 wherein:
- said layer of conductive material is formed into a closed three dimensional shape; and
said electrographic sensor further includes a fourth contact point spaced apart from said three spaced apart contact points and electrically interconnected with said layer of conductive material.
- said layer of conductive material is formed into a closed three dimensional shape; and
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30. The electrographic sensor unit of claim 29 wherein each plane defined by each combination of three of said four spaced apart contact points does not pass through a center point of said closed three dimensional shape.
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31. The electrographic sensor unit of claim 29 wherein said position of said stylus is determined by said processor causing selected signals to be applied to various combinations of said four spaced apart contact points and a measured signal received by said stylus in response to each application of signals that are used by said processor to calculate the position to which said stylus is pointed by the user:
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a first measurement is made by open circuiting each of said contact points and measuring an offset signal, SignalOFFSET, with said stylus; a second measurement is made by applying the same signal to each of said four spaced apart contact points and measuring a full signal, SignalFULL, with said stylus; a third measurement is made by applying a signal between a first two of said four spaced apart contact points with the other two contact points left unconnected, the value of the signal applied between said first two contact points has a fixed relationship to the value of the signal used to make said second measurement, and measuring a raw signal between said first two contact points, SignalRAW-FIRST-TWO, with said stylus; a fourth measurement is made by applying a signal between a second two of said four spaced apart contact points with the other two contact points left unconnected, the value of the signal applied between said second two contact points has a fixed relationship to the value of the signal used to make said second measurement, and measuring a raw signal between said second two contact points, SignalRAW-SECOND-TWO, with said stylus; a fifth measurement is made by applying a signal between a third two of said four spaced apart contact points with the other two contact points left unconnected, the value of the signal applied between said third two contact points has a fixed relationship to the value of the signal used to make said second measurement, and measuring a raw signal between those said third two contact points, SignalRAW-THIRD-TWO, with said stylus; and calculating the relative position to which said stylus is pointed by the user relative to said first two contact points, said second two contact points, and said third two contact points using the following equations, the values from those equations being coordinates on an equipotential map of the user selected point to which the user is pointing said stylus with the axes of those coordinates being imaginary lines between each of said first two contact points, said second two contact points, and said third two contact points;
space="preserve" listing-type="tabular">______________________________________ P.sub.FIRST-TWO = (Signal.sub.RAW-FIRST-TWO - (Signal.sub.OFFSET)/(Signal.sub.FULL - Signal.sub.OFFSET);
P.sub.SECOND-TWO = (Signal.sub.RAW-SECOND-TWO - (Signal.sub.OFFSET)/ (Signal.sub.FULL - Signal.sub.OFFSET);
and P.sub.THIRD-TWO = (Signal.sub.RAW-THIRD-TWO - (Signal.sub.OFFSET)/ (Signal.sub.FULL - Signal.sub.OFFSET). ______________________________________
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32. The electrographic sensor unit of claim 31 wherein:
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a predetermined signal map of said conductive material is prestored in said processor; and said calculated values of PFIRST-TWO, PSECOND-TWO, and PTHIRD-TWO are used by said processor in conjunction with said signal map to translate said calculated values into a physical position on said surface to which said user is pointing said stylus.
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33. The electrographic sensor unit of claim 1 wherein said processor includes:
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a microprocessor having a data bus associated therewith; a memory system interfacing with said data bus; a signal generator stage coupled to said microprocessor to generate and apply various signals to various ones, and various combinations, of said three spaced apart contact points under control of said microprocessor; and a signal measurement stage coupled to said microprocessor and said probe assembly to capture and condition signals received from said probe system under control of said microprocessor.
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34. The electrographic sensor unit of claim 33 wherein said signal generator stage includes:
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a signal generator; and a switching system coupled between said signal generator and said three spaced apart contact points on said layer to selectively apply a signal from said signal generator to selected ones of said three spaced apart contact points under the direction of said microprocessor.
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35. The electrographic sensor unit of claim 34 wherein:
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said memory system includes prestored information relative to various coordinates on said layer; and said processor further includes; an electronic delivery system for providing information from said memory system to said user relative the user selected position of said stylus.
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36. An electrographic sensor unit for use in determining the position of a user selected point on the surface thereof, which comprises:
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an indicator panel having; a bottom layer of a conductive material with an electrical resistivity; a top layer of a flexible conductive material; and an inner layer between said top and bottom layers wherein said inner layer is a non-conductive, compressible material; three spaced apart contact points electrically interconnected with said conductive material of said bottom layer; a processor connected to said three spaced apart contact points and disposed to selectively apply a signal to each of said three spaced apart contact points; and an electrical conductor coupled between said processor and said top layer of said indicator panel to transmit signals received by said top layer from said bottom layer when said user depresses a point on said top layer toward said bottom layer in vicinity of a user selected point on said top layer with a finger; wherein said position of said finger of said user relative to said bottom layer is determinable from two signals received from said top layer by said processor each in relation to a similar excitation of two different pairs of said three spaced apart contact points interconnected with said bottom layer. - View Dependent Claims (37, 38, 39, 40, 41, 42)
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43. An electrographic sensor unit in the form of a globe for use in determining the position of a user selected point on the surface thereof, which comprises:
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a sphere formed of a layer of a conductive material having a substantially uniform electrical resistivity and an outer surface; a set of four spaced apart contact points electrically interconnected with said layer of conductive material of said sphere; a processor connected to said set of four spaced apart contact points and disposed to selectively apply a signal to each of said four spaced apart contact points; and a probe assembly, including a stylus, coupled to said processor, said stylus disposed to be positioned by a user in vicinity of a user selected point on said surface of said sphere and to receive signals from said layer when said four spaced apart contact points have signals selectively applied thereto by said processor; wherein said position of said stylus relative to said surface of said sphere is determinable from three signals received from said stylus by said processor each in relation to a similar excitation of three different pairs of said four spaced apart contact points on said sphere by said processor. - View Dependent Claims (44, 45, 46, 47, 48, 49, 50)
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51. An electrographic sensor unit for use in determining the position of a selected point, which comprises:
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a first layer of a conductive material having an electrical resistivity and a first surface; a first set of three spaced apart contact points electrically interconnected with said first layer of conductive material; a second layer of a conductive material having an electrical resistivity and a second surface; a second set of three spaced apart contact points electrically interconnected with said second layer of conductive material; a processor connected to each of said first and second sets of three spaced apart contact points and disposed to selectively apply a signal to each of said three spaced apart contact points in each of said first and second sets thereof; and a probe assembly, including a stylus, coupled to said processor, said stylus disposed to be positioned by a user in vicinity of a user selected point on said first or second surface of said first and second layers and to receive signals from said layer associated with said user selected point when said corresponding set of three spaced apart contact points have signals selectively applied thereto; wherein identification of which of said first and second surfaces said stylus is adjacent to is accomplished by said processor by independently measuring two signals from each of said first and second layers received by said stylus, combining said signals from the same layer independent of the signals received from the other layer to form a first and a second comparative value with each said comparative value associated with a different one of said first and second layers, and independently comparing each of said first and second comparative values to a preselected threshold value with the layer associated with the one of said first and second comparative values that is greatest and is greater than said threshold value being the layer said stylus is closest to and therefore an identified layer of said first and second layers; and wherein said position of said stylus relative to said identified one of said first or second layers is determinable by said processor from signals received from said stylus each in relation to a similar excitation of all of said three contact points on the identified one of said first and second layers and two different pairs of said three spaced apart contact points on the identified one of said first and second layers under control of said processor. - View Dependent Claims (52, 53, 54, 55, 56, 57, 58, 59)
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60. A method for location of a user selected position on an electrographic sensor unit having a layer of a conductive material with an electrical resistivity and K spaced apart contact points electrically interconnected with said layer of conductive material where N of said K spaced apart contact points are used to locate said user selected position and where N has an integer value of three to K, a processor disposed to selectively apply a signal to each of said N contact points and to determine position coordinates of said user selected position, and a means for detecting and delivering a signal from the user selected position of said electrographic sensor unit to said processor, said method including the steps of:
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a. applying a first selected signal to all of said K spaced apart contact points; b. measuring a first measured signal at said user selected position with said first measured signal corresponding to the signal application of step a.; c. sequentially applying a selected second signal between J different pairs of said N of said K spaced apart contact points with said second signal having a selected relationship to said first signal, where J is an integer value between 2 and (N-1); d. sequentially measuring J second measured signals at said user selected position with each one of said J measured signals corresponding to a different one of said J second signal applications of step c.; and e. calculating a value proportional to a position coordinate between each pair of said J pairs of contact points of step c. that is proportional to a ratio of each one of said J second measured signals of step d. and said first measured signal of step b. to define said user selected position with J coordinates relative to said contact points used in said J second signal measurements. - View Dependent Claims (61, 62, 63, 64, 65, 66, 67, 68, 69, 70)
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71. A method for location of a user selected position on an electrographic sensor unit having M layers of a conductive material each electrically isolated from each other and each having an electrical resistivity and K spaced apart contact points electrically interconnected with the corresponding layer of conductive material where N of said K spaced apart contact points are used to locate said user selected position and where N has an integer value of three to K, a processor disposed to selectively apply a signal to each of said N contact points of each of said M layers and to determine which of said M layers and position coordinates of said user selected position on the corresponding one of said M layers, and a means for detecting and delivering a signal from the user selected position on said electrographic sensor unit to said processor, with the user having selected said position said method including the steps of:
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a. sequentially applying a first selected signal to all of said K spaced apart contact points on each of said M layers in turn; b. measuring a first measured signal at said user selected position for each of said M layers with said first measured signal corresponding to the signal application of step a. for each of said M layers; c. measuring a second measured signal at said user selected position on the user selected layer with each of said K spaced apart contact points on each of said M layers open circuited; d. subtracting said second measured signal from step c. from said first measured signal for each of said M layers from step b. to form M difference values; e. comparing each of said M difference values from step d. against a preselected threshold value; and f. identifying the one of said M layers on which said user selected position is located as the layer associated with the difference value that is both greater than said threshold value and that exceeds said threshold value by the greatest amount. - View Dependent Claims (72)
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73. An electrographic sensor unit for use in determining the position of a selected point, which comprises:
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a layer of a conductive material having an electrical resistivity and a surface; K spaced apart contact points electrically interconnected with said layer of conductive material; a processor connected to said K spaced apart contact points and disposed to selectively apply a signal to N of said K spaced apart contact points where N has an integer value of 3 to K; and a probe assembly, including a stylus, coupled to said processor, said stylus disposed to be positioned by a user in vicinity of a user selected point on said surface of said layer and to receive signals from said layer when N of said K spaced apart said contact points have signals selectively applied thereto; wherein said position of said stylus relative to said surface of said layer is determinable by said processor from signals received from said stylus each in relation to a similar excitation of J different pairs of said K spaced apart contact points under control of said processor, where J is an integer value of 2 to (N-1).
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Specification