Electrographic touch sensor with z-axis capability

Claim 2

An electrographic sensor for generating signals corresponding to the two dimensional coordinates of a contact point on the sensor, the sensor being capable of generating signals related to the pressure/force applied at the contact point, and comprising: 1) a resistive sheet and a further sheet. positioned proximate each other, such that the perimeter of the further sheet substantially conforms to the perimeter of the resistive sheet, and such that inner surfaces of the sheets face each other, each of the sheets a) being capable of having electrical fields introduced therein, and b) extending across the sensor, and the further sheet being adapted to move towards the resistive sheet upon the application of pressure/force, to the sensor, at the contact point; 2) means for generating orthogonal electrical fields within the sensor, in the X and Y directions, such that signals corresponding to the X- and Y-coordinates of the contact point are produced when electrical connection is made between the sheets at the contact point; and 3) enhancing means interposed between the sheets, which determines an effective contact resistance between the sheets which varies inversely with the pressure/force applied, in a manner which differentiates between levels of pressure/force applied at the contact point such that a signal corresponding to the Z-coordinate can be obtained, the Z-coordinate-signal being related to the magnitude of the pressure/force at the contact point.

Claim 3

A sensor according to claim 1, wherein at least one of the sheets is elastomeric.

Claim 4

A sensor according to claim 1 or 2, wherein the resistive sheet is an elastomeric layer provided with a resistive coating on its inner surface.

Claim 5

A sensor according to claim 3, comprising electrodes in contact with the resistive coating for receiving voltages to introduce the said electrical fields in the resistive layer, which electrodes preferably comprise a plurality of contact electrodes, spaced along the periphery of the resistive sheet, and in contact with the resistive coating.

Claim 6

A sensor according to claim 1 or 2, wherein each of the sheets is provided with a resistive layer on its inner surface, and with electrodes positioned along opposite edges of the sheet in contact with the respective resistive layers, the electrodes of one of the resistive sheets being oriented orthogonally with respect to the electrodes of the other sheet.

Claim 7

A sensor according to any one of claims 1 to 5, wherein the enhancing means comprises (a) a distribution of a material having a resistivity which is substantially greater than the resistivity of the resistive sheet: preferably (i) a grid array of a resistance material which is applied to the inner surface of the resistive sheet, the resistance material having a resistivity which is at least 1000 times greater than the resistivity of the resistive sheet, or (ii) an insulating powder interposed between the sheets, or (iii) a layer of lacquer paint, having a thickness of about 500 to 5000 Angstroms, applied to the inner surface of one of the sheets; or (b) a distribution of a material having a resistivity which is substantially greater than the resistivity of the resistive layers on the sheets; or (c) a plurality of spaced-apart buttons, made of an insulating material, and applied to the inner surface of one of the sheets.

Claim 8

An electrographic touch sensor for generating signals corresponding to the two-dimensional coordinates of a contact point on the sensor, the sensor being capable of generating signals related to the pressure/force applied at the contact point, and comprising: 1) means for generating orthogonal electrical fields within the sensor having a) a uniform resistive layer, to accept voltages to produce the orthogonal fields, and b) at least one exposed surface, the field-generating-means being adapted to generate the output signals of two-dimensional coordinates of the contact point when the sensor is contacted; 2) an array of high resistance material applied to the exposed surface of the field-generating-means, and having a resistivity substantially greater than the resistivity of the resistive layer of the field-generating-means, the array having a predetermined configuration and covering a predetermined portion of said exposed surface; and 3) a conductive sheet, having a first surface and a further surface, positioned proximate said array with its first surface towards the array; whereby when a pressure/force is applied to the sensor at the contact point it causes the first surface of the conductive sheet to make contact with the array and thereby generates signals corresponding to the two-dimensional coordinates of the contact point, and a signal corresponding to a third coordinate, which third coordinate is related to a change of the effective contact resistance between the resistive layer of the potential generating means and the conductive sheet at the contact point, as enhanced by the array.

Claim 9

An electrographic touch sensor for generating signals corresponding to the two-dimensional coordinates of a contact point on the sensor, the sensor being capable of generating signals related to the pressure/force applied at the contact point, and comprising: 1) means for generating orthogonal electrical fields within the sensor having a) a uniform resistive layer, to accept voltages to produce the orthogonal fields, and b) at least one exposed surface, the field-generating-means being adapted to generate the output signals of two-dimensional coordinates of the contact point when the sensor is contacted; 2) an array of high resistance material applied to the exposed surface of the field-generating-means, and having a resistivity substantially greater than the resistivity of the resistive layer of the field-generating-means, the array having a predetermined configuration and covering a predetermined portion of said exposed surface; and 3) a conductive sheet, having a first surface and a further surface, positioned proximate said array with its first surface towards the array; whereby when a pressure/force is applied to the sensor at the contact point it causes the first surface of the conductive sheet to make contact with the array and thereby generates signals corresponding to the two-dimensional coordinates of the contact point, and a signal corresponding to a third coordinate, which third coordinate is related to a change of the effective contact resistance between the resistive layer of the potential generating means and the conductive sheet at the contact point, as enhanced by the array.

Claim 10

A sensor according to claim 7, wherein the means for generating the orthogonal electrical potentials comprises a layer of uniform resistivity, provided with spaced-apart electrodes in contact with the layer, arranged along the perimeter of the layers, and adapted to receive voltages, the resistive layer being applied to a supporting substrate.

Claim 11

An electrographic touch sensor for generating signals corresponding to the X- and Y-coordinates of a contact point on the sensor, and being capable of generating signals related to a pressure/force related Z-coordinate of the contact point, which comprises: 1) a substrate; 2) a uniform resistive coating applied to the substrate; 3) electrode means in contact with the resistive coating proximate the perimeter edges of the coating, whereby orthogonal electrical fields can be generated in the coating upon the application of voltages to the electrode means; 4 ) an array of material applied to the resistive coating, having a resistivity substantially greater than the resistivity of the resistive coating, and having a selected configuration; and 5) a flexible conductive sheet, having a first surface and a further surface, proximate the array with said first surface towards the array; whereby when a sufficient pressure/force is applied to the further surface of the conductive sheet at the contact point it causes contact of the first surface of the conductive sheet with the array of material and thereby generates signals in the conductive sheet corresponding to the two-dimension coordinates of the point, and independently generates a signal in the conductive sheet corresponding to a reduced contact resistance between the first surface of the conductive sheet and the resistive coating, which is a function of the pressure/force applied at the contact point and is thus a function of the third coordinate.

Claim 12

An electrographic touch sensor for generating signals corresponding to the X- and Y-coordinates of a contact point on the sensor, and being capable of generating signals related to a pressure/force related Z-coordinate of the contact point, which comprises: 1) a substrate; 2) a uniform resistive coating applied to the substrate; 3) electrode means in contact with the resistive coating proximate the perimeter edges of the coating, whereby orthogonal electrical fields can be generated in the coating upon the application of voltages to the electrode means; 4 ) an array of material applied to the resistive coating, having a resistivity substantially greater than the resistivity of the resistive coating, and having a selected configuration; and 5) a flexible conductive sheet, having a first surface and a further surface, proximate the array with said first surface towards the array; whereby when a sufficient pressure/force is applied to the further surface of the conductive sheet at the contact point it causes contact of the first surface of the conductive sheet with the array of material and thereby generates signals in the conductive sheet corresponding to the two-dimension coordinates of the point, and independently generates a signal in the conductive sheet corresponding to a reduced contact resistance between the first surface of the conductive sheet and the resistive coating, which is a function of the pressure/force applied at the contact point and is thus a function of the third coordinate.

Claim 13

A sensor according to claim 9, wherein the array comprises perpendicularly oriented lines of high resistivity material defining rectangular open areas between said lines, or a resistance layer provided with substantially circular openings, or a distribution of an insulator material.

Claim 14

A sensor according to claim 9, further comprising: 4) voltage supply means; 5) sequencing means for connecting the voltage supply means to the electrode means to generate the orthogonal fields in said uniform resistive layer; 6) circuit means for receiving and processing the signals introduced into the conductive sheet corresponding to the X- and Y-coordinates of the contact point; and 7) further circuit means for receiving and processing the signal introduced into the conductive sheet corresponding to the pressure/force and thus to the Z-coordinate of such contact point.

Claim 15

A sensor according to claim 9, wherein the electrode means comprises: (a) a plurality of contact pads spaced along each of said perimeter edges; (b) a plurality of diodes, each of said diodes having a first lead connected to one of said contact pads and a further lead; (c) trace leads connected to appropriate of said further diode leads; and (d) terminals on said trace leads for the application of said voltages to said contact pads for said generation of said orthogonal electrical fields in said resistive coating.