Color Conversion Layer Structure for Thin Light-Emitting Packages

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Solution Overview

Problem

Existing light emitting devices face challenges in achieving both small and thin size while maintaining desired chromaticity and color reproducibility, particularly due to the use of poorly durable color conversion materials.

Innovation Solution

A light emitting device is manufactured using a light-transmissive member with a color conversion material layer disposed within a through-hole of a light-reflective sheet, where the sheet is flexible and self-standing, allowing for improved optical coupling efficiency and precise assembly, and the color conversion material layer is formed without voids using a light-transmissive resin containing diffusing agents for enhanced light distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If color conversion materials are used to improve chromaticity and color reproducibility, then optical performance is improved, but device thickness increases and durability decreases

Engineering Contradiction:
Improvechromaticity and color reproducibilityVSAvoiddevice thickness
Core Design Contradiction:
Illumination intensityVSLength of stationary object

Solution Approach 1:

The patent uses a flexible light-reflective sheet as the base structure, allowing the entire device to be thin yet maintain structural integrity. The sheet can be bent to conform to surfaces while supporting the color conversion materials, achieving thinness without sacrificing optical performance or durability

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent employs a porous layer between the light-emitting element and color conversion materials, and uses resin materials with controlled porosity to embed color conversion particles. This porous structure allows for material embedding while maintaining thin profile and enabling light transmission for optimal optical performance

Inventive Principle:
Principle #31Porous materials

2Illumination intensity

If color conversion materials are used to improve chromaticity and color reproducibility, then optical performance is improved, but material durability is poor

Engineering Contradiction:
Improvechromaticity and color reproducibilityVSAvoidmaterial durability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent creates composite structures by embedding color conversion particles within resin matrices, and further composites this layer with the light-reflective sheet and porous support structures. This multi-layer composite approach protects fragile color conversion materials while maintaining their optical properties and improving overall durability

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent provides protective cushioning for color conversion materials by embedding them within resin layers and positioning them between protective structural layers (porous layer, light-reflective sheet). This beforehand protection prevents damage during assembly and operation, improving material durability without affecting optical performance

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Illumination intensity

If complex assembly methods are used to achieve precise color conversion, then optical performance is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvecolor conversion qualityVSAvoidmanufacturing process complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into integrated layers: the light-reflective sheet serves as both structural support and optical element, the porous layer provides both mechanical support and material embedding, and resin layers simultaneously protect materials and enable light transmission. This merging reduces the number of separate manufacturing steps while maintaining high optical performance

Inventive Principle:
Principle #5Merging (Combining)

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 approach enables the production of light emitting devices with improved chromaticity and color reproducibility while maintaining a small and thin form factor, enhancing visibility and light distribution by optimizing the placement and properties of the color conversion material layer.

Implementation Method 1

a light-transmissive member with a color conversion material layer disposed within a through-hole

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

the color conversion material layer is formed without voids using a light-transmissive resin containing diffusing agents for enhanced light distribution

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP3734676B1Light emitting device
Publication Date: 2024.11.27 NICHIA CORP
  • EP3734676B1 patent drawingFigure 1A~1C
  • EP3734676B1 patent drawingFigure 1D~2B
  • EP3734676B1 patent drawingFigure 2C~3B

AI summary

The present invention relates to a light emitting device comprising a single light emitting element, a light-transmissive member including a light reflective sheet and a single color conversion material layer, the light reflective sheet having a through-hole, the color conversion material layer including a light-transmissive resin and a color conversion material and being disposed in the through-hole, the single color conversion material layer being disposed on the single light emitting element, a light reflective member covering side surfaces of the light emitting element, and the light emitting device having an outer side surface that is defined by the light-reflective sheet and the light reflective member.