Vehicle Lighting Device Flexible Circuit Assembly

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Solution Overview

Problem

Existing lighting devices for vehicle interiors face challenges in assembly precision, vibration resistance, and maintaining electrical contact between light sources and touch interfaces, leading to noise and potential breakage due to tolerance issues and clearance problems.

Innovation Solution

A lighting device with a mechanical assembly by clipping and a flexible mechanical and electrical connection using a conductive elastomer sleeve to ensure zero clearance and robust electrical contact, featuring a partially transparent touch interface and an optical device for light guidance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a mechanical clip-on assembly is used to join the housing and cover, then the assembly is simple and allows blind assembly, but the electrical contact between the touch interface and the light source cannot be guaranteed due to vibrations and clearance

Engineering Contradiction:
Improveassembly simplicityVSAvoidelectrical contact reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent employs a flexible printed circuit board (FPC) as the electrical connection element between the touch interface and the light source. The FPC can bend and deform to accommodate vibrations and assembly clearances while maintaining continuous electrical contact, thus resolving the contradiction between simple clip-on assembly and reliable electrical connection.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent incorporates an elastomeric element or buffer structure in the assembly that absorbs vibrations and compensates for clearance before they can affect the electrical contact. This preemptive cushioning ensures that the FPC maintains stable electrical connection despite external vibrations or assembly tolerances.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Object-affected harmful factors

If the assembly is mounted under stress to achieve zero clearance, then noise due to vibration is reduced, but the risk of breaking or desoldering the electrically conductive mechanical parts increases

Engineering Contradiction:
Improvevibration noiseVSAvoidstructural integrity
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent uses a dynamic assembly approach where the FPC and elastomeric buffer can deform elastically under stress rather than being rigidly fixed. This allows the assembly to accommodate vibrations through controlled deformation, reducing noise transmission while preventing stress concentration that could lead to breakage or desoldering.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the mechanical parameters of the connection system by using flexible materials with appropriate elasticity and damping characteristics. The FPC and elastomeric element are designed with specific stiffness and damping parameters that allow them to absorb vibrations without transmitting excessive stress to solder joints or rigid components.

Inventive Principle:
Principle #35Parameter changes

3Strength

If clearance is allowed in the assembly to avoid stress, then the risk of breaking is reduced, but noise induced by clearance appears

Engineering Contradiction:
Improvestructural safetyVSAvoidclearance-induced noise
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The FPC acts as a flexible intermediary that eliminates clearance-induced noise while maintaining structural safety. The flexible circuit board can conform to slight misalignments and clearances without creating rigid contact points that would generate noise, thus simultaneously achieving both structural safety and noise reduction.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The elastomeric buffer serves as an intermediary element between rigid components, absorbing clearance and preventing direct metal-to-metal contact that would generate noise. This mediator allows controlled movement while dampening vibrations and eliminating clearance-induced rattling.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution facilitates a simple and robust assembly, reduces noise and vibration, and maintains reliable electrical contact, ensuring consistent lighting performance and user experience.

Implementation Method 1

a flexible compressed mechanical and electrical linking means between the touch interface and the light source allowing both to control the light source

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

said assembly being assembled without play by clipping means... compensate for the stresses exerted by the clipping means

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3695165B1Lighting device
Publication Date: 2021.12.15 PSA AUTOMOBILES SA
  • EP3695165B1 patent drawingFigure 1

AI summary

A lighting device (1) comprising a housing (2) accommodating at least one light source (14), said housing (2) comprising an at least partially transparent wall (6) supporting a touch interface (7) for controlling the light source (14) and allowing through the light generated by the light source (14), and a cover (3) closing the housing (2); the assembly formed by the housing (2) and the cover (3) being tightly assembled by clipping means (4), said lighting device (1) further comprising a flexible mechanical and electrical connection means (20) compressed between the touch interface (7) and the light source (14) allowing both control of the light source (14) and compensation of the stresses exerted by the clipping means (14).