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US 10,309,846 B2Granted
Magnetic field cancellation for strain sensors
AssigneeApple Inc.
InventorJohn Stephen Smith
Life of this patent
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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.
Claims15
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.
14 more elements
Dependencies are inferred from the claim text.