Motor Vehicle LED Module Phosphor Grain Positioning

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Solution Overview

Problem

Conventional light-emitting diode (LED) modules for motor vehicles face challenges in achieving consistent color output across different viewing directions due to variability in the conversion layer's properties, leading to inconsistent lighting and signaling.

Innovation Solution

A light-emitting module comprising submillimeter light-emitting rods coated with a conversion material containing phosphor grains, where the phosphor grains are positioned in an overhanging layer beyond the free ends of the rods, ensuring they do not fit between the rods, and are embedded in a polysiloxane-based thermoplastic or thermosetting polymer coating, which converts light emitted by the rods into desired colors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If phosphor grains are used in the conversion layer, then light conversion efficiency is improved, but color consistency across viewing directions deteriorates due to grain distribution variability

Engineering Contradiction:
Improvelight conversion efficiencyVSAvoidcolor consistency
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The patent changes the physical state of phosphor from discrete grains to a phosphor paste (suspension in liquid vehicle), transforming the parameter of phosphor distribution from random granular to controlled fluid state, enabling uniform application and consistent color output across viewing directions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite conversion layer by combining phosphor particles suspended in a liquid vehicle with optional transparent binder and filler materials, forming a homogeneous phosphor paste that ensures uniform light conversion properties and consistent color appearance from all viewing angles

Inventive Principle:
Principle #40Composite materials

2Power

If conventional phosphor grains are applied, then light conversion function is achieved, but spatial homogeneity of converted light deteriorates due to uneven grain distribution

Engineering Contradiction:
Improvelight conversion functionVSAvoidspatial homogeneity
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The patent transforms phosphor from solid grain state to suspended paste state in liquid vehicle, changing the physical parameter of phosphor delivery, which enables homogeneous distribution and stable spatial composition of the conversion layer

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a liquid vehicle as an intermediary medium that carries phosphor particles uniformly, acting as a mediator to achieve homogeneous distribution of phosphor throughout the conversion layer, ensuring consistent light conversion across all spatial positions

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If phosphor grains are positioned to prevent presence between rods, then manufacturing precision is improved, but device complexity increases due to precise positioning requirements

Engineering Contradiction:
Improvephosphor grain positioningVSAvoidpositioning control
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes phosphor from discrete positionable grains to a flowable paste suspension, transforming the parameter of phosphor applicability from requiring precise placement to allowing uniform coating, thereby reducing manufacturing complexity while maintaining precision

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical approach of individually positioning phosphor grains with a chemical/physical approach of applying phosphor paste through coating processes, substituting complex mechanical positioning with simpler deposition methods that inherently achieve uniform distribution

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 configuration enhances the spatial homogeneity of the converted light, providing a consistent color output that meets regulatory photometric requirements, improving the overall lighting and signaling performance of motor vehicle lighting systems.

Implementation Method 1

a conversion material suitable for generating said converted light from the light emitted by the light-emitting rods, the conversion material comprising a plurality of phosphor grains

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

a coating adapted to encapsulate the light-emitting rods and to convert at least a portion of the light emitted by the rods into converted light

Methodology Applied
Scientific EffectLight conversion through phosphor: Photoluminescence

Data Source

PatentEP3479012B1An improved signalling and/or lighting device, in particular for a motor vehicle
Publication Date: 2021.03.03 VALEO VISION SA
  • EP3479012B1 patent drawingFigure 1~2
  • EP3479012B1 patent drawingFigure 3~5
  • EP3479012B1 patent drawing

AI summary

An improved signalling and/or lighting device, in particular for a motor vehicle. A light-emitting module, in particular for a motor vehicle. The light-emitting module comprises: -a light source (12) comprising a plurality of light-emitting rods (16), and -a layer (20) suitable for encapsulating the light-emitting rods and for converting at least some of the light emitted by the rods into converted light, said layer comprising: ° a converting sublayer (24) extending beyond a free end of the light-emitting rods (16), said converting sublayer comprising a luminophore compound (26) that is suitable for generating said converted light from the light emitted by the light-emitting rods, the luminophore compound taking the form of grains (30) the dimensions of which are selected to prevent the presence of said grains between spaces defined laterally between the rods, and ° an encapsulating sublayer (22) in which at least some of the light-emitting rods (16) are embedded.