Matched-Pair Resistive Sensor Magnetic Interference Avoidance
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Solution Overview
Problem
Strain-responsive sensors in electronic devices are affected by interference from changing magnetic fields, which can impact the accuracy and precision of force input detection due to components like speakers and haptic feedback elements.
Innovation Solution
The implementation of a strain-responsive sensor design featuring matched-pair resistive structures where current flows in the same direction through both structures, configured as a closed loop to minimize the impact of induced electromotive forces from changing magnetic fields, thereby avoiding interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional strain-sensitive elements are used to detect deformation, then the sensor can measure strain from force input, but the measurement is affected by interference from changing magnetic fields generated by components like speakers and haptic feedback elements
Solution Approach 1:
The patent converts the harmful effect of magnetic field interference into a beneficial configuration by designing the resistive structures to form closed loops. The induced electromotive forces from magnetic fields now circulate within these closed loops rather than creating measurement errors, as the induced currents become self-contained and do not interfere with the strain measurement signal path.
Solution Approach 2:
The patent changes the electrical configuration parameter of the resistive structures from open-loop to closed-loop topology. This parameter change fundamentally alters how the structures respond to magnetic fields, transforming the interference mechanism into a non-interfering configuration where induced currents remain confined within the closed loops.
2Device complexity
If resistive structures are configured in open-loop topology, then the sensor structure is simpler, but induced electromotive forces from changing magnetic fields create noise and interference
Solution Approach 1:
The patent converts the harmful induced electromotive forces into a beneficial configuration by forming closed loops. The induced EMFs now generate circulating currents that remain confined within the closed loops, preventing them from appearing as noise in the measurement circuit while maintaining structural simplicity.
3Adaptability or versatility
If speakers and haptic feedback elements are included in the electronic device, then the device functionality is enhanced, but changing magnetic fields from these components interfere with sensor operation
Solution Approach 1:
The patent enables coexistence of speakers, haptic feedback elements, and sensors by converting the magnetic field interference into a non-harmful configuration. The closed-loop resistive structures allow induced currents to circulate internally without affecting the sensor output, enabling full device functionality without sensor degradation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces noise and maintains the accuracy and precision of force input detection by ensuring that induced currents do not interfere with the sensor's operation, even in the presence of changing magnetic fields.
Implementation Method 1
minimize the impact of induced electromotive forces from changing magnetic fields
Data Source
AI summary
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 of the matched pair 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.