# US 10,309,846 B2 · Magnetic field cancellation for strain sensors > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,309,846 B2 - Document ID: US10309846B2 - Status: Granted - Kind: B2 - Application number: 15/658,387 - Filed: 2017-07-24 - Published: 2019-01-24 - Granted: 2019-06-04 - Earliest claimed: 2017-07-24 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: John Stephen Smith - Web page: https://patentgrep.com/patent/US10309846B2 ## CPC - G01L 1/2268: {Arrangements for correcting or for compensating unwanted effects} - G06F 3/0418: {for error correction or compensation, e.g. based on parallax, calibration or alignment} - G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A strain-responsive sensor incorporating a strain-sensitive element is disclosed. The strain-sensitive element includes a matched-pair of resistive structures disposed on opposite sides of a substrate. One resistive structure is coupled to a crossover, either a physical crossover or a soft crossover, such that current within the resistive structures of the matched pair flows in the same direction. In addition, one resistive structure of the matched pair has a different loop area than the other resistive structure. ## Claims ### Claim 1 An electronic device comprising: an enclosure housing a display; a cover sheet positioned over the display and forming an external surface of the electronic device; a magnetic interference source positioned within the enclosure; and a strain-sensing layer positioned beneath the cover sheet and comprising: a substrate comprising an upper surface and a lower surface; a first strain-sensing element comprising: a first upper resistive structure comprising a first set of conductive traces and coupled to the upper surface of the substrate; and a first lower resistive structure comprising a second set of conductive traces aligned along an axis passing perpendicular through the substrate with the first set of conductive traces and coupled to the lower surface of the substrate; and a second strain-sensing element positioned adjacent the magnetic interference source and comprising: a second upper resistive structure comprising a third set of conductive traces and coupled to the upper surface of the substrate; and a second lower resistive structure comprising a fourth set of conductive traces and coupled to the lower surface of the substrate; wherein at least a portion of the fourth set of conductive traces does not align along the axis with the third set of conductive traces. ### Claim 2 (depends on 1) The electronic device of claim 1, wherein a first central conductive trace of the third set of conductive traces is not aligned with a second conductive trace of the fourth set of conductive traces; and remaining traces of the third set of conductive traces are aligned with remaining traces of the fourth set of conductive traces. ### Claim 3 (depends on 1) The electronic device of claim 1, wherein the substrate is formed from at least one of glass, polyimide, or polyethylene terephthalate. ### Claim 4 (depends on 1) The electronic device of claim 1, wherein at least one upper resistive structure has a spiral shape. ### Claim 5 (depends on 1) The electronic device of claim 1, wherein each upper resistive structure is formed from the same material. ### Claim 6 (depends on 5) The electronic device of claim 5, wherein each lower resistive structure is formed from the same material. ### Claim 7 (depends on 1) The electronic device of claim 1, wherein the substrate is coupled to the display. ### Claim 8 (depends on 1) The electronic device of claim 1, wherein the second strain-sensing element further comprises a crossover coupled to the second lower resistive structure such that current within the second lower resistive structure flows in the same direction as current within the second upper resistive structure. ### Claim 9 (depends on 1) The electronic device of claim 1, wherein the first upper resistive structure is formed from at least one of indium tin oxide, a copper-nickel alloy, a copper-nickel-iron allow, or a copper-nickel manganese alloy. ### Claim 10 (depends on 1) The electronic device of claim 1, wherein the first lower resistive structure has a same shape as the first upper resistive structure. ### Claim 11 (depends on 8) The electronic device of claim 8, wherein the crossover is a physical crossover. ### Claim 12 (depends on 8) The electronic device of claim 8, wherein the crossover is a soft crossover. ### Claim 13 (depends on 1) The electronic device of claim 1, wherein the first and second strain-sensing elements are part of a group of strain-sensing elements. ### Claim 14 (depends on 1) The electronic device of claim 1, further comprising: a first reference resistor; and a second reference resistor; wherein the first and second upper resistive structures, the first and second lower resistive structures, the first reference resistor, and the second reference resistor are coupled in a balancing network. ### Claim 15 (depends on 14) The electronic device of claim 14, wherein an electrical circuit is configured to measure a voltage output from the balancing network.