Optical Fiber Automotive Lighting Safety Mechanism

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Solution Overview

Problem

Current automotive lighting assemblies using optical fibers are not safe in the event of a breakage, as broken fibers can direct intense light outside the headlight or taillight, potentially blinding or damaging individuals.

Innovation Solution

Incorporating a radially emitting optical fiber with a converging intermediate lens and photometric sensors to detect light intensity and automatically deactivate the light source if there is a breakage or misalignment, preventing accidental light leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If optical fibres are used to channel light from LEDs towards transparent sectors, then assembly is simplified and flexibility is improved, but safety deteriorates in the event of breakage as fibres can move and direct light outside the housing

Engineering Contradiction:
Improveassembly simplicityVSAvoidlight leakage hazard
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A black pigment is introduced as an intermediary substance within the optical fiber to absorb and block light transmission. This pigment creates a safety mechanism that prevents light leakage even when the fiber breaks or moves, while maintaining the fiber's flexibility and assembly advantages.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The potential harm of light leakage in broken fibers is converted into a benefit by using the black pigment to actively block light. The same optical fiber that could potentially leak light when broken is transformed into a safe component through the light-absorbing pigment embedded within it.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Illumination intensity

If high-power LEDs or laser emitters are used to increase light intensity, then illumination performance is improved, but safety deteriorates as broken fibres can direct intense light outside the headlight/taillight

Engineering Contradiction:
Improvelight intensityVSAvoideye damage risk
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The black pigment acts as an intermediary safety mechanism within the optical fiber system. It selectively blocks light transmission when the fiber is compromised, while allowing normal high-intensity light transmission when the fiber is intact and properly positioned.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The black pigment is embedded in advance within the optical fiber structure, providing beforehand protection against light leakage. This preventive measure ensures that even if the fiber breaks or moves during operation, the light is blocked before it can escape and cause harm.

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

3Reliability

If a light-guide bar made of PMMA is used to backlight transparent sectors, then light guidance is effective, but assembly becomes laborious due to alignment requirements and fragility

Engineering Contradiction:
Improvelight guidance effectivenessVSAvoidassembly difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the rigid PMMA light-guide bar with flexible optical fibers. These fibers can be easily manipulated and positioned, eliminating the alignment precision requirements and fragility issues associated with rigid light-guide bars, while maintaining effective light guidance through total internal reflection.

Inventive Principle:
Principle #30Flexible shells and thin films

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

Enhances the safety of automotive lighting assemblies by ensuring that light is not accidentally directed outside the assembly in case of breakage or misalignment, maintaining safety and reliability.

Implementation Method 1

Light that then travels inside the body of the light-guide bar by total internal reflection, and usually exits progressively from the lateral side of the light-guide bar directly facing the front half-shell

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a small converging lens is usually placed between the LED and the end of the optical fibre, which lens concentrates the light rays exiting from the LED towards the facing end of the optical fibre

Methodology Applied
Scientific EffectConverging lens focusing: Lens

Data Source

PatentEP4019832A1Automotive lighting apparatus
Publication Date: 2022.06.29 MARELLI AUTOMOTIVE LIGHTING ITAL SPA
  • EP4019832A1 patent drawingFigure 1
  • EP4019832A1 patent drawingFigure 2
  • EP4019832A1 patent drawingFigure 3

AI summary

Automotive lighting apparatus (1) provided with a lighting assembly (4) comprising: an optical fibre (6) of given length; an electrically-powered light source (5), which is placed in front of a proximal end (6a) of the optical fibre (6), and is selectively adapted to direct, towards the same proximal end (6a), a light beam that enters and travels inside the optical fibre (6); and an intermediate lens (7), which is interposed between the proximal end (6a) of the optical fibre (6) and the light source (5), and is adapted to focus the light exiting from the light source (5) towards the behind-located proximal end of the optical fibre (6); and at least one proximal photometric sensor (9) which is arranged beside the collimated light source (5) and/or the intermediate lens (7), so as to capture/detect the light reflected/dispersed by said intermediate lens (7); the intermediate lens (7) having, on its front face, one surface chamfer or notch (7a) which is adapted to direct/reflect the incident light at least partly towards said proximal photometric sensor (9).