# US 8,786,356 B2 · Conductive shield for shaping an electric field of a conductive wire > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,356 B2 - Document ID: US8786356B2 - Status: Granted - Kind: B2 - Application number: 13/539,648 - Filed: 2012-07-02 - Published: 2013-05-16 - Granted: 2014-07-22 - Earliest claimed: 2011-11-14 - Assignees: Atmel Corporation - Applicants: Andrew Siska - Inventors: Andrew Siska - Web page: https://patentgrep.com/patent/US8786356B2 ## CPC - G06F 3/041662: {using alternate mutual and self-capacitive scanning} - G01R 27/2605: {Measuring capacitance (capacitive sensors G01D5/24)} - G06F 3/0445: {using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer} - H03K 17/962: {Capacitive touch switches} - G06F 2203/04107: Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds - G06F 2203/04108: Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction - H03K 2217/960765: Details of shielding arrangements - H03K 2217/96078: Sensor being a wire or a strip, e.g. used in automobile door handles or bumpers - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract In one embodiment, a method comprises generating, by a control unit, a first drive signal and a second drive signal. The method further comprises emitting, by a conductive wire coupled to a capacitive touch sensor, a first electric field that extends in a plurality of directions in response to reception of the first drive signal. The method further comprises shaping, by a conductive shield that surrounds the conductive wire, at least a portion of the first electric field that extends from the capacitive touch sensor towards the conductive shield by generating a second electric field in response to reception of the second drive signal. ## Claims ### Claim 1 A device comprising: a capacitive touch sensor configured to store an amount of charge indicative of whether an object is within a range of the capacitive touch sensor; a conductive wire coupled to the capacitive touch sensor, the conductive wire configured to transport a first drive signal to the capacitive touch sensor to charge the capacitive touch sensor, the conductive wire generating a first electric field when transporting the first drive signal; a dielectric layer surrounding a first portion of the conductive wire; a conductive shield surrounding the dielectric layer and the first portion of the conductive wire, the conductive shield configured to transport a second drive signal, the conductive shield generating a second electric field when transporting the second drive signal, the second electric field shaping the first electric field generated by the conductive wire; a control unit coupled to the conductive wire and the conductive shield, the control unit configured to generate the first drive signal and the second drive signal; an amplifier configured to amplify the first drive signal to generate the second drive signal; a sensing unit configured to sense whether an object is within the range of the capacitive touch sensor based on the amount of charge stored by the capacitive touch sensor; and a logic circuit in communication with the sensing unit and configured to initiate an action of the device based upon a determination by the sensing unit of whether an object is within the range of the capacitive touch sensor. ### Claim 2 (depends on 1) The device of claim 1, wherein the action initiated by the logic circuit includes turning off the engine of a machine in response to a determination that an object is not within the range of the capacitive touch sensor. ### Claim 3 (depends on 1) The device of claim 1, further comprising a metal steering column of a machine, the metal steering column surrounding at least a portion of the conductive wire and at least a portion of the shielding cable. ### Claim 4 (depends on 1) The device of claim 1, wherein the capacitive touch sensor is a second portion of the conductive wire that is not surrounded by the conductive shield or the dielectric layer. ### Claim 5 (depends on 1) The device of claim 1, wherein the first portion of the conductive wire has a length of at least 10 centimeters. ### Claim 6 (depends on 1) The device of claim 1, wherein the amplifier is implemented using a buffer configured to amplify the first drive signal to generate the second drive signal. ### Claim 7 (depends on 1) The device of claim 1, wherein the first drive signal and the second drive signal have the same phase and polarity. ### Claim 8 (depends on 1) The device of claim 1, further comprising another conductive shield configured to generate a third electric field in response to receiving the second drive signal, the third electric field shaping a fourth electric field generated by the capacitive touch sensor in response to receiving the first drive signal. ### Claim 9 An apparatus comprising: a capacitive touch sensor configured to store an amount of charge indicative of whether an object is within a range of the capacitive touch sensor; a conductive wire coupled to the capacitive touch sensor, the conductive wire configured to transport a first drive signal to the capacitive touch sensor to charge the capacitive touch sensor, the conductive wire generating a first electric field when transporting the first drive signal; and a conductive shield surrounding a first portion of the conductive wire, the conductive shield configured to transport a second drive signal, the second drive signal having an amplitude that is greater than an amplitude of the first drive signal, the conductive shield generating a second electric field when transporting the second drive signal, the second electric field shaping the first electric field generated by the conductive wire. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the capacitive touch sensor is a second portion of the conductive wire that is not surrounded by the shielding cable. ### Claim 11 (depends on 9) The apparatus of claim 9, further comprising an amplifier configured to amplify the first drive signal to generate the second drive signal. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein the amplifier is implemented using a buffer configured to amplify the first drive signal to generate the second drive signal. ### Claim 13 (depends on 9) The apparatus of claim 9, wherein the conductive wire is a center conductor of a coaxial cable. ### Claim 14 (depends on 9) The apparatus of claim 9, further comprising a dielectric layer between the conductive shield and the conductive wire, the dielectric layer surrounding the first portion of the conductive wire. ### Claim 15 (depends on 9) The apparatus of claim 9, further comprising another conductive shield configured to generate a third electric field in response to receiving the second drive signal, the third electric field shaping a fourth electric field generated by the capacitive touch sensor in response to receiving the first drive signal. ### Claim 16 (depends on 9) The apparatus of claim 9, wherein the first drive signal and the second drive signal have the same phase and polarity. ### Claim 17 (depends on 9) The apparatus of claim 9, wherein the capacitive touch sensor is a conductive plate. ### Claim 18 A method comprising: generating, by a control unit, a first drive signal and a second drive signal, the second drive signal having an amplitude that is greater than an amplitude of the first drive signal; emitting, by a conductive wire coupled to a capacitive touch sensor, a first electric field that extends in a plurality of directions in response to reception of the first drive signal; and shaping, by a conductive shield that surrounds the conductive wire, at least a portion of the first electric field that extends from the capacitive touch sensor towards the conductive shield by generating a second electric field in response to reception of the second drive signal. ### Claim 19 (depends on 18) The method of claim 18 further comprising: measuring an amount of charge stored by the capacitive touch sensor by transferring the charge from the capacitive touch sensor to the control unit through the conductive wire; and detecting whether an object is within a range of the capacitive touch sensor based on the measured amount of charge. ### Claim 20 (depends on 18) The method of claim 18, wherein the first drive signal and the second drive signal have the same phase and polarity.