Flexible Printed Circuit Board for Strain Gauge Signal Integrity
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Solution Overview
Problem
Implementing strain gauges in car door handles is challenging due to difficulties in wiring and obtaining quality signals, with mechanical connections being cumbersome and prone to noise from electromagnetic interference.
Innovation Solution
A detection system utilizing a flexible printed circuit board to establish reliable connections between strain gauges and an electronic control unit, allowing for easier installation and reduced noise, with features like multiple soldering points and a foldable design to fit within the handle or car door geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If typical electrical wires are used to connect strain gauge to electronic control unit, then wiring flexibility is improved, but connection reliability deteriorates due to mounting difficulties and fragile electrical connections
Solution Approach 1:
A flexible printed circuit board (FPC) is introduced as an intermediary component between the strain gauge and the electronic control unit. The FPC provides structured connection points that solder to the strain gauge, eliminating the need for fragile wire connections while maintaining flexibility through the inherent properties of the flexible circuit board material
Solution Approach 2:
The patent replaces the mechanical wire connection system with an integrated flexible circuit board system. Instead of using separate wires that require manual routing and connection, the FPC provides a pre-fabricated, reliable electrical pathway that combines structural support with electrical connectivity
2Ease of operation
If strain gauge is mounted inside handle with limited space, then user experience is improved by enabling push-to-open operation, but signal quality deteriorates due to electromagnetic noise from other handle components
Solution Approach 1:
The flexible printed circuit board serves as an intermediary that electrically connects the strain gauge to the control unit while providing electrical isolation from other handle components. The FPC's layered structure and grounding capabilities help shield the sensitive strain gauge signal from electromagnetic interference generated by other electronic parts in the handle
Solution Approach 2:
The flexible printed circuit board uses thin, flexible substrate material that can be easily installed in the confined space of the handle. This thin-film structure allows the circuit to conform to the limited available space while maintaining electrical performance and providing isolation from external electromagnetic noise sources
3Reliability
If flexible printed circuit board is used instead of electrical wires, then connection reliability is improved, but device complexity increases due to additional intermediate component
Solution Approach 1:
The flexible printed circuit board merges multiple functions into a single component: it provides structural support for the strain gauge, establishes reliable electrical connections through solder points, routes signals to the control unit, and provides electrical isolation. This consolidation reduces the number of separate components and simplifies the overall wiring structure despite the added reliability
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 flexible printed circuit board ensures a stable and noise-reduced electrical connection, facilitating the installation and operation of strain gauges within car door handles, improving signal quality and user experience.
Implementation Method 1
A strain gauge is a sensor whose deformation is a function of its electrical resistance when a current is circulating through it
Implementation Method 2
The connecting points of the at least one strain gauge and the corresponding connection area of the flexible printed circuit board are configured to be connected by at least two distinct soldering points
Data Source
AI summary
A detection system for a handle of a car access assembly that includes a sensing module and a flexible printed circuit board. The sensing module includes at least one strain gauge having a sensing area and connection points in contact with the sensing area so as to permit the measurement of a signal at the connection points. The flexible printed circuit board has a first end with at least one connection area adapted to be connected to the connection points of the at least one strain gauge and a second end with a connection arrangement configured to be connected to an electronic control unit.