Automotive Optical Fiber Lighting With Sensor-Based Laser Shutoff

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Solution Overview

Problem

The use of radially emitting optical fibers in automotive lighting assemblies poses safety risks due to potential breakage during accidents, as the laser light can escape and cause eye damage if the optical fiber is not properly aligned or if it breaks, leading to increased assembly complexity and time.

Innovation Solution

Incorporating a collimated light source with proximal and distal photometric sensors to detect light intensity at both ends of the optical fiber, an electronic control unit activates or deactivates the light source based on the ratio of light intensity detected, ensuring safe operation by preventing accidental laser beam exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a radially emitting optical fiber is used in the lighting assembly, then the assembly process becomes more complex and time-consuming due to the need for precise alignment and fragility handling, but the lighting performance is improved

Engineering Contradiction:
Improvelighting performanceVSAvoidassembly complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent divides the lighting assembly into separate modules: the optical fiber is separated from the housing, and the laser light source is mounted independently on a circuit board. This segmentation allows each component to be prepared and tested separately before final assembly, reducing the complexity of aligning fragile optical fibers during assembly while maintaining precise alignment through dedicated mounting structures.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If a radially emitting optical fiber is used in the lighting assembly, then the assembly process becomes more complex and time-consuming due to the need for precise alignment and fragility handling, but the flexibility of the lighting system is improved

Engineering Contradiction:
Improvesystem flexibilityVSAvoidassembly complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The optical fiber is separated as an independent component that can be routed flexibly through the housing to reach the desired backlighting positions. This segmentation allows the fiber to be installed in complex pathways without requiring the entire assembly to be rigid, thereby maintaining system flexibility while reducing assembly complexity through modular preparation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes the inherent flexibility of the optical fiber to route it through the housing structure in adaptable pathways. The fiber's flexibility allows it to conform to various spatial arrangements and reach distant backlighting points without requiring rigid structural support, thereby achieving adaptability while simplifying the overall assembly process.

Inventive Principle:
Principle #30Flexible shells and thin films

3Object-affected harmful factors

If the optical fiber breaks or becomes misaligned, then laser light can escape and cause eye damage, but implementing safety monitoring increases device complexity

Engineering Contradiction:
Improvesafety against laser exposureVSAvoidmonitoring system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where photometric sensors continuously monitor the light output from the optical fiber. When the sensors detect abnormal light levels indicating fiber breakage or misalignment, they send signals to the control unit, which then deactivates the laser light source. This feedback loop provides automatic safety monitoring without requiring complex manual intervention systems.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The safety monitoring system is designed to automatically detect and respond to fiber failures without external intervention. The photometric sensors and control unit work together to self-diagnose the fiber status and automatically deactivate the laser source when needed, thereby providing safety functionality while minimizing the complexity of external monitoring infrastructure.

Inventive Principle:
Principle #25Self-service

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 enhances active safety by preventing accidental laser beam exposure in case of breakage or misalignment, simplifies assembly, and ensures reliable operation by monitoring light intensity ratios, independent of power fluctuations or temperature variations.

Implementation Method 1

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

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

at least one proximal photometric sensor that is arranged beside the collimated light source and/or the proximal end of the optical fibre, so as to capture/detect the light reflected/scattered on entering into the optical fibre; at least one distal photometric sensor that is arranged in front of the distal end of the optical fibre and is adapted to capture/detect the light coming out of the distal end of the optical fibre

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3839332B1Automotive lighting apparatus and relative control method
Publication Date: 2024.01.24 MARELLI AUTOMOTIVE LIGHTING ITAL SPA
  • EP3839332B1 patent drawingFigure 1
  • EP3839332B1 patent drawingFigure 2
  • EP3839332B1 patent drawingFigure 3~5

AI summary

Automotive lighting apparatus (1) comprising: a rear body (2) which is adapted to be fixed to the outside or to the inside of the vehicle; a front half-shell (3) arranged to close the mouth of said rear body (2); and at least one lighting assembly (4) which is located inside the rear body (2) and is adapted to backlight, on command, a corresponding transparent or semi-transparent sector of the front half-shell (3); the lighting assembly (4) comprising: a radially emitting optical fibre (6) of given length; an electrically-powered, collimated light source (5) which is located in front of a proximal end (6a) of the optical fibre (6), and is adapted to direct, towards the same proximal end (6a), a collimated light beam (r) that enters and travels inside the optical fibre (6); at least one proximal photometric sensor (8) which is arranged beside the collimated light source (5) and/or the proximal end (6a) of the optical fibre (6) so as to capture/detect the light reflected/scattered on entering into the optical fibre (6); at least one distal photometric sensor (9) which is located in front of the distal end (6b) of the optical fibre (6), and is adapted to capture/detect the light exiting from the distal end (6b) of the optical fibre (6); and an electronic control unit (7) which is adapted to command the collimated light source (5) on the basis of the signals coming from said proximal (8) and distal (9) photometric sensors.