Single-Layer Wavelength Converter for LED Lighting

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Solution Overview

Problem

Existing wavelength converters for LEDs often require multiple layers with different wavelength converting compositions, increasing complexity and cost, and are prone to optical interference and delamination due to interfaces between layers, which can affect performance and longevity.

Innovation Solution

A single layer wavelength converter is developed using a polymeric matrix material with a specific distribution of quantum dot particles and phosphor particles, where the density of the matrix precursor is tailored to control the settling of these particles, ensuring a uniform distribution within the converter, thereby eliminating the need for multiple layers and reducing optical interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple layers with different wavelength converting compositions are used, then the wavelength conversion performance is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvewavelength conversion performanceVSAvoidnumber of layers
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple wavelength converting compositions (phosphor particles and quantum dot particles) into a single layer structure. The polymeric matrix encapsulates both types of particles together, eliminating the need for separate layers while maintaining the wavelength conversion functionality. This merging approach reduces manufacturing complexity and eliminates interfacial delamination issues between multiple layers.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses a composite material system consisting of a polymeric matrix combined with both phosphor particles and quantum dot particles. This composite structure allows different wavelength converting materials to coexist in a single phase, achieving multiple wavelength conversion functions simultaneously while simplifying the overall device architecture.

Inventive Principle:
Principle #40Composite materials

2Reliability

If multiple layers with different wavelength converting compositions are used, then the wavelength conversion performance is improved, but optical interference and delamination occur at interfaces

Engineering Contradiction:
Improvewavelength conversion performanceVSAvoidoptical interference and delamination
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

By merging phosphor particles and quantum dot particles into a single layer within a polymeric matrix, the patent eliminates the interfaces that would otherwise exist between multiple layers. This removes the sources of optical interference and delamination while preserving the wavelength conversion performance of both material types.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a homogeneous single layer structure where phosphor particles and quantum dot particles are distributed together within the polymeric matrix. This uniform distribution eliminates interfacial boundaries between different wavelength converting layers, preventing both optical interference and delamination issues.

Inventive Principle:
Principle #33Homogeneity

3Productivity

If quantum dot particles and phosphor particles are distributed uniformly, then the wavelength conversion efficiency is improved, but particle settling during curing becomes difficult to control

Engineering Contradiction:
Improvewavelength conversion efficiencyVSAvoidparticle distribution uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent controls particle distribution by carefully selecting and adjusting the density of the polymeric matrix precursor. By matching the density parameters of the matrix precursor with those of the embedded particles (phosphor and quantum dots), the invention prevents unwanted particle settling during the curing process, ensuring uniform distribution and high conversion efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses the density characteristics of the final desired particle distribution as a guide for selecting the matrix precursor density. By copying the density requirements needed for uniform particle suspension in the cured state, the matrix precursor is formulated to maintain that same uniform distribution during the curing process, preventing particle settling.

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

The single layer wavelength converter simplifies manufacturing, enhances optical performance by minimizing interfaces, and improves the longevity of LED packages by reducing the risk of delamination, while maintaining effective light conversion capabilities.

Implementation Method 1

The wavelength conversion material generally functions to convert primary light to secondary light via photoluminescence. In some instances the wavelength conversion material absorbs relatively high energy primary light, which can excite the wavelength conversion material to a higher energy state. When the wavelength conversion material returns to a lower energy state it emits secondary light

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

the density of the matrix precursor is tailored to control the settling of these particles, ensuring a uniform distribution within the converter

Methodology Applied
Scientific EffectSedimentation: Sedimentation

Data Source

PatentEP3172770B1Wavelength converters and methods for making the same
Publication Date: 2021.06.02 OSRAM SYLVANIA INC
  • EP3172770B1 patent drawingFigure 1
  • EP3172770B1 patent drawingFigure 2A~2C
  • EP3172770B1 patent drawingFigure 2D~2E

AI summary

Disclosed herein are wavelength converters and methods for making the same. The wavelength converters include a single layer of a polymeric matrix material, and one or more types of wavelength converting particles. In some embodiments the wavelength converters include first and second types of wavelength converting particles that are distributed in a desired manner within the single layer of polymeric matrix material. Methods of forming such wavelength converters and lighting devices including such wavelength converters are also disclosed.