PCB Grounding Structure for Semiconductor Light Power Control

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Solution Overview

Problem

Existing methods for grounding a printed circuit board in semiconductor light source control devices, particularly in motor vehicle light modules, are prone to damage due to the use of crimping pins or screws, especially when the housing material is hard, leading to potential mechanical stress and failure.

Innovation Solution

The implementation of a device with multiple contact points and mass belts for grounding, providing specific support and protection to the printed circuit board, and using Zamak for the housing and protective cover to enhance durability and precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a crimping pin or screw is used to ground the printed circuit board, then a ground connection is achieved, but the printed circuit board may break under combined stresses from the fastening element and housing

Engineering Contradiction:
Improveground connection reliabilityVSAvoidprinted circuit board strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The ground connection is segmented from the mechanical fastening function. Multiple contact points are distributed across the housing surface, separating the grounding function from any single fastening element, thereby eliminating the concentrated stress that causes PCB breakage while maintaining reliable ground connection

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The housing acts as an intermediary element between the PCB and the external environment. The contact points transfer ground connection through the housing material without requiring direct mechanical fastening of the PCB, allowing the housing to mediate the connection while protecting the PCB from stress

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a crimping pin or screw is used to ground the printed circuit board, then grounding is achieved, but the housing material hardness limits the available options

Engineering Contradiction:
Improveground connection reliabilityVSAvoidhousing material adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The mechanical fastening system (screws or crimping pins) is replaced with a contact-based system. The contact points establish ground connection through electrical contact rather than mechanical fastening, allowing compatibility with various housing materials including hard materials that would be difficult or impossible to thread or crimp

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If multiple contact points are used for grounding, then ground connection reliability is improved, but the device complexity increases

Engineering Contradiction:
Improveground connection reliabilityVSAvoidcontact point structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The grounding function is merged with the housing structure itself. The contact points are integrated into the housing design, combining the support function and ground connection function into a single structural element, thereby improving reliability without proportionally increasing device complexity

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3358926B1Device for controlling the electric power supply for a semiconductor light source
Publication Date: 2024.11.20 VALEO VISION SA
  • EP3358926B1 patent drawingFigure 1
  • EP3358926B1 patent drawingFigure 2
  • EP3358926B1 patent drawingFigure 3~4

AI summary

The invention relates to a device (10) for controlling the power supply for a semiconductor light source for a light module, the control device (10) comprising: - a printed circuit board (3) comprising at least an electronic component (3B) for controlling the power supply; - a box (5) adapted to accommodate said printed circuit board (3); - a protective cover (7) to close said box (5); - a first ground belt (3C) disposed on a first face (3A') of said printed circuit board (3) and a second ground belt disposed on a second face of said printed circuit board (3) opposite the first face (3A'); the box (5) having first points of contact (5A") with the second mass belt and said protective cover (7) having second points of contact with said first mass belt (3C), said box (5) and/or said protective cover (7) comprising at least one protective wall (5B') for all or part of said first (5A") and second contact points.