Light-converting Material Nanoparticle Surface Placement

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Solution Overview

Problem

Existing light-converting materials for LEDs, particularly those using semiconductor nanoparticles and conventional phosphors, suffer from issues such as high reabsorption and self-absorption, leading to reduced energy efficiency, inadequate color rendering, and difficulties in controlling color space, along with challenges in production flexibility and material homogeneity.

Innovation Solution

A light-converting material comprising semiconductor nanoparticles located on the surface of a luminescent material, where the emission of the nanoparticles matches the emission range of the luminescent material, reducing reabsorption and enhancing miscibility with conventional phosphors, thereby improving efficiency and production flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If semiconductor nanoparticles are used in light-converting materials, then color space controllability and emission tuning are improved, but reabsorption and self-absorption increase, reducing energy efficiency

Engineering Contradiction:
Improvecolor space controllabilityVSAvoidenergy efficiency
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The invention divides the light conversion function into two separate components: a luminescent material that converts pump light to a first wavelength, and semiconductor nanoparticles that convert this first wavelength to a second wavelength. This segmentation prevents the nanoparticles from being exposed to the original pump light, eliminating self-absorption losses while maintaining color tuning capabilities through nanoparticle selection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The luminescent material acts as an intermediary between the pump light source and the semiconductor nanoparticles. It absorbs the pump light and emits at a wavelength that matches the absorption band of the nanoparticles, enabling efficient energy transfer while preventing the nanoparticles from absorbing pump light directly, thus avoiding reabsorption losses.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If conventional phosphors are used for white light generation, then ease of manufacture is improved, but color rendering quality deteriorates due to bluish cool-white light and poor green/red spectral content

Engineering Contradiction:
Improveease of manufactureVSAvoidcolor rendering quality
Core Design Contradiction:
Ease of manufactureVSIllumination intensity

Solution Approach 1:

The invention creates a composite light-converting material combining a luminescent material (such as YAG:Ce) with semiconductor nanoparticles having different emission wavelengths. This composite structure maintains the ease of manufacturing conventional phosphors while adding spectral components in the green and red regions through nanoparticle emission, thereby improving overall color rendering quality.

Inventive Principle:
Principle #40Composite materials

3Illumination intensity

If quantum dots are used to improve light quality, then color rendering is improved, but self-absorption increases, reducing overall energy efficiency

Engineering Contradiction:
Improvelight qualityVSAvoidenergy efficiency
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The system segments the excitation and emission processes: the luminescent material handles excitation by pump light and emits at a wavelength suitable for nanoparticle absorption, while the nanoparticles handle the final wavelength conversion to desired colors. This prevents quantum dots from absorbing pump light directly, eliminating self-absorption while maintaining high light quality.

Inventive Principle:
Principle #1Segmentation

4Illumination intensity

If red phosphors are used to extend emission into long-wavelength red range, then color rendering is improved, but LED brightness and efficiency are reduced

Engineering Contradiction:
Improvecolor renderingVSAvoidLED brightness
Core Design Contradiction:
Illumination intensityVSPower

Solution Approach 1:

The invention changes the approach to red emission by using semiconductor nanoparticles with可调 emission wavelengths instead of conventional red phosphors. By selecting nanoparticles with specific band gaps that match the luminescent material emission, the system achieves red emission with higher quantum efficiency and maintains LED brightness, avoiding the efficiency losses associated with deep red phosphors.

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 results in higher energy efficiency, improved color space controllability, reduced material consumption, and enhanced production flexibility, enabling brighter and more stable LEDs with targeted emission adjustment.

Implementation Method 1

semiconductor nanoparticles... the emission of the semiconductor nanoparticles lies in the emission range of the luminescent material

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP3729520B1Light-converting material
Publication Date: 2025.09.24 LITEC VERMOGENSVERWALTUNGS GMBH
  • EP3729520B1 patent drawingFigure 1~2
  • EP3729520B1 patent drawingFigure 3~4
  • EP3729520B1 patent drawingFigure 5~6

AI summary

The invention relates to a light-converting material, which contains a luminescent material having semiconductor nanoparticles (quantum materials), wherein the semiconductor nanoparticles are located on the surface of the luminescent material and the emission of the semiconductor nanoparticles lies in the range of the emission of the luminescent material. The invention further relates to a method for producing the light-converting material and to the use thereof in a light source. The invention further relates to a light-converting mixture, to a light source, to an illumination unit containing the light-converting material according to the invention, and to a method for producing said light-converting mixture, said light source and said illumination unit.