Electrographic touch sensor with Z-axis capability
First Claim
1. An electrographic touch sensor for generating signals of two-dimension coordinates of a contact point on said sensor, and having a capability of generating signals related to pressure/force applied at such point, which comprises:
- a resistive sheet capable of having electrical potentials introduced therein extending across such sensor, said resistive sheet defining a perimeter and having an inner and outer surface;
a further sheet capable of having electrical potentials introduced therein positioned proximate said resistive sheet and extending across such sensor, said further sheet defining a perimeter substantially conforming to said perimeter of said resistive sheet, and having an inner surface facing said inner surface of said resistive sheet, and an outer surface, said further sheet adapted to move toward said resistive sheet upon the application of pressure/force to such sensor at a selected point;
means for generating orthogonal electrical potentials within such sensor in X and Y directions whereby signals corresponding to X- and Y-coordinates of said selected point can be produced when electrical connection is made between said resistive and further sheets at said selected point; and
enhancing means interposed between said inner surfaces of said resistive and further sheets whereby an effective contact resistance between said resistive and further sheets varies inversely with said pressure/force in a manner to differentiate between levels of pressure/force at said selected point such that said X- and Y-coordinate signals and a Z-coordinate signal can be obtained, said Z-coordinate signal being related to said pressure/force at said selected point.
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Accused Products
Abstract
An electrographic touch sensor having Z-axis capability. In one embodiment, a uniform resistive coating is applied to one surface of a substrate and it is within this coating that orthogonal electrical fields are produced using suitable electrodes and voltage applications to give coordinates of a selected position. Overlying the resistive coating is a flexible pickoff sheet having a conductive layer facing the combination. Interposed between the resistive coating and the conductive layer is an array of a material having a substantially greater resistivity than that of the resistive coating. Signals corresponding to the X- and Y-coordinates of a touched point on the sensor are obtained in a substantially conventional manner using an amplifier and an analog to digital converter. If desired, a Z-axis component signal due to pressure/force can be obtained in a separate part of the measuring cycle. This Z-axis signal is inversely related to a change in the effective contact resistance between the resistive coating and the pick-off sheet caused by the pressure/force. The change in this contact resistance is "enhanced" by the high resistance material such that different values of pressure/force can be determined. Numerous other embodiments are described including two resistive sheet sensors and enhancing materials that are considered to be insulators.
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Citations
30 Claims
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1. An electrographic touch sensor for generating signals of two-dimension coordinates of a contact point on said sensor, and having a capability of generating signals related to pressure/force applied at such point, which comprises:
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a resistive sheet capable of having electrical potentials introduced therein extending across such sensor, said resistive sheet defining a perimeter and having an inner and outer surface; a further sheet capable of having electrical potentials introduced therein positioned proximate said resistive sheet and extending across such sensor, said further sheet defining a perimeter substantially conforming to said perimeter of said resistive sheet, and having an inner surface facing said inner surface of said resistive sheet, and an outer surface, said further sheet adapted to move toward said resistive sheet upon the application of pressure/force to such sensor at a selected point; means for generating orthogonal electrical potentials within such sensor in X and Y directions whereby signals corresponding to X- and Y-coordinates of said selected point can be produced when electrical connection is made between said resistive and further sheets at said selected point; and enhancing means interposed between said inner surfaces of said resistive and further sheets whereby an effective contact resistance between said resistive and further sheets varies inversely with said pressure/force in a manner to differentiate between levels of pressure/force at said selected point such that said X- and Y-coordinate signals and a Z-coordinate signal can be obtained, said Z-coordinate signal being related to said pressure/force at said selected point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An electrographic touch sensor for generating signals of two-dimension coordinates of a contact point on said sensor, and having a capability of generating signals related to pressure/force applied at such point, which comprises:
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means for generating orthogonal electrical potentials within such sensor, said means having a uniform resistive layer and electrodes attached to said resistive layer to accept voltages to produce said orthogonal fields, said means having at least one exposed surface, said means further adapted to generate such signals of two-dimension coordinates of such contact point; an array of high resistance material applied to said exposed surface of said means, the resistivity value of said material of said array being substantially greater than the resistivity value of said resistive layer, said array having a selected configuration and covering a selected portion of said exposed surface; a conductive sheet, having a first surface and a further surface, proximate said array with said first surface toward said array; whereby a pressure/force applied to such sensor at such point causes said first surface of said conductive sheet to make contact with at least said array and thereby generate such signals of such two-dimension coordinates of such point, and such signal of a third coordinate related to a change of effective contact resistance between said resistive layer and said conductive sheet at such point, as enhanced by said array, produced by said pressure/force. - View Dependent Claims (18)
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19. An electrographic touch sensor for generating signals of X- and Y-coordinates of a contact point on said sensor, and having a capability of generating signals related to a pressure/force related Z-coordinate of such point, which comprises:
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a substrate; a uniform resistive coating applied to said substrate, said coating having perimeter edges; electrode means in contact with said resistive coating proximate said perimeter edges whereby orthogonal electrical fields are generatable in said coating upon the application of voltages to said electrode means; an array of material applied to said resistive coating, the resistivity value of said material of said array being substantially greater than the resistivity value of said resistive coating, said array having a selected configuration; a flexible conductive sheet, having a first surface and a further surface, proximate said array with said first surface toward said array; whereby a sufficient pressure/force applied to said further surface of said conductive sheet at such contact point produces contact of said first surface of said conductive sheet with at least said array of said material and thereby generates signals in said conductive sheet corresponding to such two dimension coordinates of such point, and independently generates a signal in said conductive sheet corresponding to a reduced contact resistance between said first surface of said conductive sheet and said resistive coating as a function of said pressure/force applied at such point and thus to such third coordinate. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
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28. A method for obtaining a signal corresponding to pressure/force applied to an electrographic touch sensor at a selected point, such sensor of the type having a pair of closely disposed layers, at least one of such layers being a resistive layer having a selected uniform resistivity value, such sensor adapted to provide signals corresponding to the X- and Y-coordinates of such selected point, said method comprising:
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applying a distributed array of enhancing material between such layers, the resistivity value of said material of said array being substantially greater than such selected resistivity value of such resistive layer; generating orthogonal electrical fields in such sensor; obtaining signals generated in such layers corresponding to such X- and Y-coordinates upon applying such pressure/force at such selected point; and obtaining a further signal, generated during a separate time interval, related to a change in effective contact resistance between such layers upon application of such pressure/force at such selected point, said further signal increasing as a function of such pressure/force applied to such sensor at such point as said effective contact resistance is reduced upon an increase in said pressure force. - View Dependent Claims (29, 30)
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Specification