Sensor Package Non-Conductive Substrate Eddy Current Reduction
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Solution Overview
Problem
Existing magnetic field sensors are prone to accuracy issues due to eddy currents generated in conductive lead frames, especially when sensing alternating magnetic fields, leading to reduced robustness and accuracy.
Innovation Solution
A sensor package design featuring a non-conductive substrate with sensing elements on one side and non-sensing elements on the other, with conductive connections minimized to reduce exposure to magnetic fields, using materials like glass-reinforced epoxy laminate to minimize eddy currents and enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conductive lead frame is used for wiring sensor elements and integrated circuit, then electrical connectivity is achieved, but eddy currents are generated in alternating magnetic fields reducing sensor accuracy
Solution Approach 1:
The patent extracts the harmful conductive lead frame from the sensor structure and replaces it with a non-conductive support structure. The lead frame is completely removed and its wiring function is replaced by conductive traces integrated into the substrate, eliminating the source of eddy currents while maintaining electrical connectivity through alternative means.
Solution Approach 2:
The patent changes the electrical conductivity parameter of the support structure from conductive (lead frame) to non-conductive (substrate material), fundamentally altering the electrical properties to eliminate eddy current generation while maintaining mechanical support and positioning functions.
2Object-affected harmful factors
If slots are introduced into the lead frame to disrupt eddy currents, then eddy current flow is reduced, but the magnitude of eddy currents remains substantial and accuracy is still affected
Solution Approach 1:
Instead of partially modifying the lead frame with slots, the patent completely extracts the lead frame structure and replaces it with a non-conductive substrate, eliminating the eddy current problem at its source rather than attempting to mitigate it through partial modifications.
3Measurement precision
If a non-conductive paddle is placed on the lead frame and integrated circuit for shielding, then eddy currents for the integrated circuit are reduced, but eddy currents for surrounding elements remain and manufacturing complexity increases
Solution Approach 1:
The patent merges the shielding function with the structural support function by making the substrate itself non-conductive. The non-conductive substrate serves dual purposes: providing mechanical support for mounting sensor elements and ICs, and simultaneously shielding all components from eddy currents, eliminating the need for separate shielding paddles.
Solution Approach 2:
The non-conductive substrate performs multiple functions simultaneously: it provides mechanical support, electrical insulation, eddy current shielding, and mounting surface for all sensor components, replacing the need for separate lead frame and shielding structures.
4Volume of moving object
If sensing elements are located close to the magnetic field source for compact design, then sensor size is reduced, but exposure to magnetic field variations increases eddy current effects
Solution Approach 1:
The patent changes the electrical conductivity parameter of the substrate to non-conductive, eliminating eddy current generation entirely. This allows the sensing elements to be positioned close to the magnetic field source for compact design without the accuracy degradation that would normally result from eddy currents in the support structure.
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
The design increases sensor accuracy by reducing eddy currents and allows for a compact, robust sensor configuration that can effectively measure both static and dynamic magnetic fields with improved precision.
Implementation Method 1
a magnetic field may cause eddy currents in the other elements of the sensor such as conductive elements... a non-conductive substrate, at least two sensing elements located at a first side of the non-conductive substrate, at least one non-sensing element located at the second side of the non-conductive substrate
Data Source
AI summary
A sensor package comprises a non-conductive substrate, at least two electrically conductive coils located at a first side of the non-conductive substrate, an evaluation circuit located at a second side of the non-conductive substrate opposing the first side of the non-conductive substrate and conductive connections between the at least two electrically conductive coils and the evaluation circuit.