Automotive Light Guide Plate for Compact Taillight Design

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Solution Overview

Problem

Existing taillights that produce U- or L- shaped luminous areas require a large number of LEDs, leading to high production costs and the need for additional heat dissipation devices.

Innovation Solution

The use of a light-guide plate made of photoconductive material with a perimeter light-exit band that directs light to create U- or L- shaped luminous areas, allowing for a reduced number of LEDs and improved heat management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a large number of LEDs are used to create U- or L- shaped luminous areas, then the light distribution and visual effect are improved, but the production cost increases and heat dissipation requirements increase

Engineering Contradiction:
Improveluminous area distributionVSAvoidproduction cost
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The patent introduces a light guide plate as an intermediary component between the LEDs and the transparent sector. The light guide plate receives light from a reduced number of LEDs and distributes it uniformly across the entire U- or L- shaped luminous area through total internal reflection and controlled light extraction, eliminating the need for numerous individual LEDs while maintaining excellent light distribution

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent merges multiple light-emitting functions into a single integrated light guide plate structure. Instead of using numerous separate LEDs for different segments of the U- or L- shaped luminous area, the light guide plate combines all light emission and distribution functions into one component, simplifying the overall structure and reducing component count

Inventive Principle:
Principle #5Merging (Combining)

2Illumination intensity

If a large number of LEDs are used to create U- or L- shaped luminous areas, then the light distribution and visual effect are improved, but the device complexity increases due to heat dissipation requirements

Engineering Contradiction:
Improveluminous area distributionVSAvoidheat dissipation structure
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent extracts the heat dissipation function from the lighting system by using LEDs with inherently low heat generation characteristics. By replacing numerous high-power LEDs with a reduced number of LEDs coupled with an efficient light guide plate, the system generates significantly less heat, eliminating the need for complex heat dissipation structures

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The light guide plate creates an optical copy or distribution of the light source across the entire luminous area. Instead of placing physical light sources (LEDs) at every location where light is needed, the system uses a single light source that optically replicates its emission across the U- or L- shaped light guide plate through total internal reflection and controlled light extraction

Inventive Principle:
Principle #26Copying

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 taillights with U- or L- shaped luminous areas using fewer LEDs, resulting in lower production costs and a more compact design while maintaining effective heat dissipation.

Implementation Method 1

Once entered into the light-guide plate, the light emitted by the LEDs propagates within the body of the light-guide plate by total internal reflection, up to reach the front sidewall from where it comes out directed towards the facing transparent or semi-transparent sector of the front half-shell

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a light-guide plate made of photoconductive material with a perimeter light-exit band that directs light to create U- or L- shaped luminous areas

Methodology Applied
Scientific EffectPhotoconductivity: Photoconductivity

Data Source

PatentEP4206523B1Automotive light
Publication Date: 2025.05.28 MARELLI AUTOMOTIVE LIGHTING ITAL SPA
  • EP4206523B1 patent drawingFigure 1~3
  • EP4206523B1 patent drawingFigure 2
  • EP4206523B1 patent drawingFigure 4~5

AI summary

An automotive light (1) provided with at least one lighting assembly (4), which is located inside the rear body (2) and is adapted to backlight a corresponding transparent or semi-transparent sector of the front half-shell (3); said lighting assembly (4) comprising: at least a first light-guide plate (10, 110) of given thickness, which is made of photoconductive material, is located inside the rear body (2) with a first face facing the front half-shell (3) and a second face facing the bottom of the rear body (2); has a perimeter light-exit band (13, 113) extending along the perimeter of the first face of the light-guide plate (10, 110), for at least two consecutive sides of the same light-guide plate (10, 110), and is structured so as to cause the light to come out of the same light-guide plate (10, 110); and finally has, on its first or second face, also a light-distributing recess (14, 114) of given shape, which has a depth less than the local thickness (s) of the light-guide plate (10, 110), and is shaped so as to distribute the light coming from the first lateral sidewall (12, 112) of the light-guide plate (10, 110) substantially along the whole length of the perimeter light-exit band (13, 113).