White Light Source Using Lanthanide Conversion Lasers for High CRI

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Solution Overview

Problem

Existing high-brightness light sources face challenges in achieving high intensity and acceptable color rendering index (CRI) without the need for additional red and green laser diodes, particularly in applications like projection, stage-lighting, and automotive lighting.

Innovation Solution

A light generating system comprising a first and second laser, along with a luminescent material, generates light using a single pump laser, eliminating the need for additional red and green laser diodes, and includes a simplified architecture for high intensity light sources with acceptable CRI.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single pump laser with luminescent materials is used to generate light, then the device complexity is reduced and architecture is simplified, but the ability to achieve high intensity with acceptable CRI becomes challenging

Engineering Contradiction:
Improvedevice complexityVSAvoidlight intensity
Core Design Contradiction:
Device complexityVSIllumination intensity

Solution Approach 1:

The patent segments the light generation process into multiple laser cavities (first, second, and optionally third cavities) that operate in sequence or parallel. Each cavity contains specific luminescent materials that convert pump laser light into different wavelength ranges, enabling the system to achieve both high intensity and acceptable CRI through divided functional units rather than a single complex source

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The single pump laser serves multiple functions by pumping different luminescent materials in various cavities to generate different wavelength components. This multi-functionality allows one light source to perform the work that would traditionally require multiple specialized lasers, simplifying the overall device architecture while maintaining performance

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

2Illumination intensity

If additional red and green laser diodes are used to achieve acceptable CRI, then the color quality improves, but the device complexity and architectural complexity increase

Engineering Contradiction:
Improvecolor qualityVSAvoiddevice complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent merges the functions of multiple laser diodes (red, green, and blue) into a unified system using a single pump laser that excites different luminescent materials within integrated cavity structures. This combining approach achieves acceptable CRI through coordinated emission from multiple materials while avoiding the complexity of separate laser diode assemblies and their associated control systems

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Luminescent materials serve as intermediaries that convert the pump laser's wavelength into the required red, green, and blue components. These intermediary materials enable wavelength transformation without requiring direct generation from multiple laser diodes, simplifying the system architecture while maintaining color quality

Inventive Principle:
Principle #24Intermediary (Mediator)

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 system achieves high brightness and acceptable CRI by utilizing a single pump laser with luminescent materials, providing a simplified architecture that enhances light intensity and color quality in applications such as projection and automotive lighting.

Implementation Method 1

a phosphor element made of a phosphor element material for converting pump radiation into conversion radiation

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

a scattering element embodied as a volume scatterer; wherein the scattering element is arranged in direct optical contact with the phosphor element in order to be transilluminated by the conversion radiation

Methodology Applied
Scientific EffectVolume scattering: Scattering

Data Source

PatentEP4416804B1White light source
Publication Date: 2025.09.03 SIGNIFY HOLDING BV
  • EP4416804B1 patent drawingFigure 1~2
  • EP4416804B1 patent drawingFigure 3~4
  • EP4416804B1 patent drawingFigure 5~6

AI summary

The invention provides a light generating system (1000) comprising (a) first light generating device (110), (b) a first laser (2100), and (c) a second laser (2200), wherein:- the first light generating device (110) is configured to generate first device light (111) having a first device centroid wavelength (λcd,1), wherein the first light generating device (110) comprises one or more of a solid state material laser and a super luminescent diode;- the first laser (2100) comprises a first lanthanide based luminescent material (2110) configured to convert at least part of the first device light (111) having the first device centroid wavelength (λcd,1) into first luminescent material light (2111), wherein the first laser (2100) is configured downstream of the first light generating device (110) and is configured to provide first laser light (2101) comprising at least part of the first luminescent material light (2111), wherein the first laser light (2101) has a first centroid laser wavelength (λcl,1) in the visible;- the second laser (2200) comprises a second lanthanide based luminescent material (2210) configured to convert at least part of the first device light (111) having the first device centroid wavelength (λcd,1) into second luminescent material light (2211), wherein the second laser (2200) is configured downstream of the first light generating device (110) and is configured to provide second laser light (2201) comprising at least part of the second luminescent material light (2211), wherein the second laser light (2201) has a second centroid laser wavelength (λcl,2) in the visible, wherein |λcl,2-λcl,1|≥25 nm;- the first centroid laser wavelength (λcl,1) and the second centroid laser wavelength (λcl,2) are selected from different wavelength ranges from the group of (i) 495-570 nm, (ii) 570-590 nm, (iii) 590-620 nm, and (iv) 620-780 nm, and- in a first operational mode of the light generating system (1000) the light generating system (1000) is configured to provide system light (1001) comprising the first laser light (2101) and the second laser light (2201), and wherein in the first operational mode the system light (1001) is white light.