FPCB Grounding via Folded Substrate Stiffening

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Solution Overview

Problem

Existing light modules for motor vehicles using flexible printed circuit boards (FPCBs) face challenges in ground recovery, requiring additional components and occupying more volume, which increases production costs and reduces design flexibility in restricted spaces.

Innovation Solution

A light module design featuring a metallic ground device with a flexible substrate and a support plate, where the flexible substrate is stiffened by a foldable second portion that establishes a ground connection without additional dedicated components, allowing for efficient ground recovery and reduced part usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrically conductive rivets are used to ground the FPCB, then grounding is achieved, but the usable area of the printed circuit board is reduced and device complexity increases

Engineering Contradiction:
Improvegrounding connectionVSAvoidgrounding components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The substrate integrates both structural support and electrical grounding functions into a single component. The substrate includes a first portion that supports electronic components and a second portion that provides grounding through an electrically conductive trace, eliminating the need for separate grounding rivets or components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The substrate serves multiple functions: it provides mechanical support for electronic components, acts as an electrical insulator where needed, and provides electrical grounding through its conductive trace. This multi-functionality reduces the overall component count and simplifies the device structure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If additional grounding components are used, then grounding is ensured, but volume occupation increases

Engineering Contradiction:
Improvegrounding connectionVSAvoidmodule volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The grounding function is merged into the substrate itself rather than being implemented as a separate component. The second portion of the substrate contains an electrically conductive trace that directly provides grounding, eliminating the volume occupied by additional grounding components.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If the substrate is kept fully flexible, then ease of placement is improved, but structural support for components is reduced

Engineering Contradiction:
Improvesubstrate placementVSAvoidcomponent support
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The substrate is divided into two distinct portions: a first portion that is flexible and supports electronic components, and a second portion that provides structural reinforcement and grounding. This segmentation allows each portion to be optimized for its specific function while working together as a unified structure.

Inventive Principle:
Principle #1Segmentation

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 solution enables ground connection for electronic circuits on FPCBs using the substrate's flexibility, reducing the need for extra components and minimizing volume occupation, thereby lowering production costs and enhancing design flexibility in motor vehicle lighting systems.

Implementation Method 1

a single fold of the substrate relative to the first portion of substrate, the fold being such that the second portion of substrate is in contact with said support plate and such that the electrically conductive trace achieves grounding

Methodology Applied
Scientific EffectFolding: Folding

Data Source

PatentEP3209098B1Light module for a motor vehicle with ground socket
Publication Date: 2023.07.12 VALEO VISION SA
  • EP3209098B1 patent drawingFigure 1~3
  • EP3209098B1 patent drawingFigure 4a~7

AI summary

The invention provides a lighting module comprising a flexible substrate integrated circuit of the FPCB type. The grounding of the electronic circuit housed on the printed circuit board is achieved without the need for additional mounting hardware. Compared to known techniques in the art, the invention allows for the creation of a lighting module with fewer component parts and a smaller footprint.