Vehicle Lighting Substrate Tab for ESD Ground Contact Stability

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Solution Overview

Problem

Existing lighting devices for motor vehicles incur additional manufacturing costs due to the use of an add-on component for electrostatic discharge prevention and substrate deformation, which also leads to potential LED shifting and reduced luminous efficacy.

Innovation Solution

A lighting device with a rigid substrate having a cutout forming a tab with electrical traces, allowing elastic deformation for electrostatic discharge prevention without an add-on component, maintaining contact through reversible bending, and using a thick, high Young's modulus substrate to minimize LED displacement and maintain luminous efficacy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an add-on component with flexible portion is used to prevent electrostatic discharge and substrate deformation, then electrostatic discharge protection and substrate stability are improved, but manufacturing costs increase due to additional materials, supplies, and assembly processes

Engineering Contradiction:
Improveelectrostatic discharge protectionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the electrostatic discharge protection function directly into the substrate structure by creating a tab from the substrate material itself that contacts the grounding element. This eliminates the need for separate add-on components while maintaining the electrostatic discharge protection function, thereby reducing manufacturing complexity and costs.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The substrate is designed to serve multiple functions: it provides mechanical support for the LED, conducts electrical signals, and simultaneously provides electrostatic discharge protection through the integrated tab structure. This multi-functionality eliminates the need for dedicated ESD protection components, reducing overall device complexity.

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

2Manufacturing precision

If an add-on component is used to prevent substrate deformation, then LED position stability is improved, but manufacturing costs increase

Engineering Contradiction:
ImproveLED position stabilityVSAvoidcomponent quantity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The substrate structure is designed with an integrated tab that inherently provides mechanical stability to prevent LED deformation. By merging the stabilization function into the substrate itself rather than using separate components, the invention reduces component quantity while maintaining manufacturing precision.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a rigid substrate with high Young's modulus and sufficient thickness is used, then contact maintenance between substrate and bulk component is improved, but substrate stress and force on tab contacts increase

Engineering Contradiction:
Improvecontact maintenanceVSAvoidsubstrate stress
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The invention optimizes the substrate thickness parameter to a specific range (0.4-2.0 mm, preferably 0.8-1.6 mm) and selects materials with appropriate Young's modulus (5-30 GPa, preferably 10-20 GPa). These parameter changes ensure sufficient mechanical strength for contact maintenance while limiting excessive stress accumulation in the substrate and forces on tab contacts.

Inventive Principle:
Principle #35Parameter changes

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

Reduces manufacturing costs by eliminating the need for an add-on component while ensuring effective electrostatic discharge protection and maintaining LED position, thus preserving luminous efficacy and regulatory functions.

Implementation Method 1

contact between the substrate and the bulk component is maintained by elastic deformation of the tab, preferably in bending

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4073426B1Lighting device for a motor vehicle
Publication Date: 2026.03.18 VALEO VISION SA
  • EP4073426B1 patent drawingFigure 1~2d
  • EP4073426B1 patent drawingFigure 3a~4
  • EP4073426B1 patent drawingFigure 5

AI summary

Lighting device for a motor vehicle, comprising a light source (3; 13) and/or an optical part (21), a substrate (2; 12) comprising electrical tracks, said light source (3; 13) and/or optical part (21) being fastened to said substrate (2; 12), and a part (4, 14) forming an electrical ground for said electrical tracks, wherein the substrate (2; 12) comprises a cut-out (6; 16) forming a tab (7; 17), electrical tracks of the substrate (2; 12) extending onto said tab (7; 17), at least one of said tracks on said tab (7; 17) making electrical contact with the ground-forming part (4; 14).