Transparent Diffusion Screen with Conical Cavities for Vehicle Lighting

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Solution Overview

Problem

Existing vehicle lighting systems, particularly rear lights, suffer from a milky or grainy appearance due to the distribution and size of conical cavities in diffusion screens, which affects aesthetics and light transmission and diffusion performance.

Innovation Solution

A transparent diffusion screen with conical cavities of specific dimensions and arrangements, ensuring they are imperceptible to observers at a distance, while maintaining photometric efficiency and allowing effective light diffusion for signaling functions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conical cavities are distributed in the diffusion zone with larger size or higher density, then light diffusion performance is improved, but the blade exhibits a milky or grainy appearance that deteriorates aesthetics

Engineering Contradiction:
Improvelight diffusion performanceVSAvoidaesthetic appearance
Core Design Contradiction:
Illumination intensityVSShape

Solution Approach 1:

The patent applies parameter changes by precisely controlling the size (diameter 0.05-0.5mm) and distribution density of conical cavities in the diffusion zone. This optimization allows the cavities to effectively diffuse light while remaining imperceptible to observers, thereby eliminating the milky appearance while maintaining diffusion performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements local quality by creating a diffusion zone with specific cavity characteristics only in the lateral light entry area, while other regions of the blade maintain different properties. This localized approach enables effective light diffusion at the entry zone without compromising the overall aesthetic appearance of the entire blade.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If the blade thickness is increased, then light transmission and diffusion effectiveness are improved, but the weight and material consumption increase

Engineering Contradiction:
Improvelight transmission effectivenessVSAvoidmaterial consumption
Core Design Contradiction:
Illumination intensityVSQuantity of substance

Solution Approach 1:

The patent employs porous materials by incorporating conical cavities within the blade structure, particularly in the diffusion zone. These cavities enable effective light diffusion and transmission without requiring increased blade thickness, thereby reducing material consumption while maintaining optical performance.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent applies parameter changes by optimizing the blade thickness to a specific range (2-10mm) and incorporating cavities with controlled dimensions and distribution. This optimized parameter combination achieves effective light transmission and diffusion while minimizing material usage compared to solid thick blades.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If the cavities are made visible to enhance diffusion effect, then light diffusion is improved, but the aesthetic appearance is compromised

Engineering Contradiction:
Improvelight diffusion effectVSAvoidvisual imperfection
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by precisely controlling the cavity diameter to be between 0.05mm and 0.5mm, which is large enough to effectively diffuse light but small enough to remain imperceptible to the human eye from normal viewing distances. This parameter optimization resolves the contradiction between visible diffusion effect and aesthetic appearance.

Inventive Principle:
Principle #35Parameter changes

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 provides a crystal-clear appearance without compromising light transmission or diffusion, preserving the photometric efficiency of light sources and enhancing the aesthetic appeal while meeting standard signaling requirements.

Implementation Method 1

the internal face of the blade comprises, in a diffusion zone, cavities, in part at least conical, which are distributed over the diffusion zone... the transparent screen also being adapted to transmit the incident light

Methodology Applied
Scientific EffectLight diffusion: Scattering

Implementation Method 2

a blade made of transparent material to form a light guide... configured to direct the light issuing from the light source inside or in the thickness of the blade

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

a blade made of transparent material to form a light guide... adapted to transmit the incident light

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 4

the diffusion screen makes it possible to obtain homogeneity of the light issuing from the first source as well as of the light reflected by a reflector

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3359419B1Transparent diffusion screen and vehicle light using this diffusion screen
Publication Date: 2020.03.25 MARELLI AUTOMOTIVE LIGHTING FRANCE
  • EP3359419B1 patent drawingFigure 1~4
  • EP3359419B1 patent drawingFigure 2
  • EP3359419B1 patent drawingFigure 5

AI summary

The invention relates to a diffusion screen made up of a sheet (10) of transparent material to form a light guide with an internal face (Fi), an external face (Fe) and at least one lateral light input zone (12) configured to direct the light coming from the lateral light source (11) into the sheet (10), the internal face (Fi) comprising, in a diffusion zone (Z), cavities (20) that are at least partially conical and which are distributed over the diffusion zone (Z), the sheet (10) having a thickness (e) comprised between 1 mm and 8 mm and the dimensions of the cavities (20) being chosen so that when the sheet (10) is illuminated by a normal beam, the cavities (20) are not individually visible to an observer of 10/10 visual acuity looking at the external face in a normal direction from a distance of more than 50 cm.