Automotive Taillight Light-Guide Layout for Uniform Logo Backlighting

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Solution Overview

Problem

Oblong taillights with a central horizontal light-guide bar struggle to accommodate an additional lighting assembly to produce a luminous version of the car manufacturer's logo due to dimensional constraints, resulting in low and uneven light intensity.

Innovation Solution

The automotive light design incorporates a pair of longitudinal light-guide bars with plate-like heads and a central shielding mask, allowing for a compact and efficient lighting assembly that produces a high-intensity, uniform luminous flux to backlight the logo.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a horizontal light-guide bar is used to backlight the central ribbon-like sector, then the light distribution is improved, but there is insufficient space to accommodate an additional lighting assembly for the logo

Engineering Contradiction:
Improvelight distributionVSAvoidspace availability
Core Design Contradiction:
Illumination intensityVSVolume of moving object

Solution Approach 1:

The patent divides the lighting system into separate functional modules: the existing horizontal light-guide bar for ribbon-like sector backlighting, and a new vertical light-guide bar for logo backlighting. This segmentation allows each lighting function to have its dedicated light path and space requirement, resolving the conflict between maintaining light distribution quality and accommodating additional lighting assemblies within the constrained volume.

Inventive Principle:
Principle #1Segmentation

2Volume of moving object

If the light-guide bar is flattened to reduce volume, then space is saved, but the light intensity becomes low and uneven

Engineering Contradiction:
Improvespace occupationVSAvoidlight intensity uniformity
Core Design Contradiction:
Volume of moving objectVSIllumination intensity

Solution Approach 1:

The patent transitions from a flattened two-dimensional light-guide structure to a three-dimensional vertical light-guide bar configuration. This dimensional change allows the light-guide bar to maintain sufficient volume for uniform light generation while occupying space in the vertical dimension rather than expanding horizontally, thus preserving light intensity uniformity without excessive volume increase.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Illumination intensity

If a vertical light-guide bar is added for logo backlighting, then logo illumination is achieved, but the device complexity increases

Engineering Contradiction:
Improvelogo backlighting capabilityVSAvoidlighting assembly structure
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The vertical light-guide bar is designed to serve multiple functions: it provides backlighting for the logo, defines the central axis of the taillight assembly, and works in conjunction with the horizontal light-guide bar to create a coordinated lighting system. This multi-functionality reduces the need for additional separate structural elements, thereby limiting the increase in device complexity while achieving the desired logo illumination.

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

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 enables the production of a high-intensity, uniform luminous flux, allowing for optimal backlighting of the car manufacturer's logo while maintaining a compact and economical lighting assembly.

Implementation Method 1

a light-guide plate that is located behind said marks-carrying lens and is adapted to backlite the same lens to highlight the mark

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP4206522B1Automotive light
Publication Date: 2025.06.04 MARELLI AUTOMOTIVE LIGHTING ITAL SPA
  • EP4206522B1 patent drawingFigure 1~2
  • EP4206522B1 patent drawingFigure 3
  • EP4206522B1 patent drawingFigure 4

AI summary

An automotive light (1) comprising a lighting assembly (5) which is located inside the rear body (2), is adapted to backlight a corresponding transparent or semitransparent sector of the front half-shell (3), and comprises: a pair of light-guide bars (8) made of photoconductive material, which extend toward each other inside the rear body (2), while remaining both substantially grazing the front half-shell (3), and have their respective proximal ends (8a) adjacent and aligned to one another; and a pair of electrically-powered light sources (9) that are located within the rear body (2) each adjacent to the distal end (8b) of a respective light-guide bar (8), and are oriented so as to direct the light produced inside the body of the facing light-guide bar (8); the proximal ends (8a) of both light-guide bars (8) being shaped so as to form respective plate-like heads (11) that are locally substantially coplanar to each other and are arranged inside the rear body (2) one spaced beside the other, so as to form/delimit therebetween a small transversal slot (12), which is substantially straight and is inclined with respect to the local longitudinal axis (L) of the same light-guide bars (8).