Phosphor Composition in LED Packages for High-CRI White Light
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light-emitting device packages struggle to achieve optimal light-emitting efficiency and color rendering index (CRI) while maintaining a high speed of light and low product defects.
Innovation Solution
A light-emitting device package is designed with a specific weight ratio of wavelength conversion materials, including a green wavelength conversion material, a first red wavelength conversion material (Mn4+ active phosphor), and a second red wavelength conversion material (Eu2+ active phosphor with controlled oxygen content), to emit white light with a CRI of 90 or more and an R9 value of 50 or more from blue light emitted by a semiconductor light-emitting device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional wavelength conversion materials are used, then the structure is simple, but the light-emitting efficiency and color rendering index are insufficient
Solution Approach 1:
The patent employs a composite wavelength conversion layer containing multiple phosphor materials (yellow phosphor, red phosphor, and green phosphor) with specific weight ratios. This composite material approach enables simultaneous achievement of high light-emitting efficiency and excellent color rendering index by combining the complementary emission characteristics of different phosphors, directly resolving the contradiction between structural simplicity and performance.
Solution Approach 2:
The patent optimizes the weight ratios of different wavelength conversion materials as key parameters. Specifically, it controls the yellow phosphor at 65-85 wt%, red phosphor at 5-30 wt%, and green phosphor at 5-30 wt%. By precisely adjusting these compositional parameters, the invention achieves optimal light-emitting efficiency and color rendering while maintaining a relatively simple package structure.
2Reliability
If multiple wavelength conversion materials are used to improve CRI, then the color rendering improves, but the device complexity increases
Solution Approach 1:
The patent merges multiple wavelength conversion materials into a single integrated wavelength conversion layer that is directly formed on the semiconductor light-emitting device. This combining approach achieves high CRI through the synergistic effect of yellow, red, and green phosphors while avoiding the need for separate complex packaging structures for each phosphor type.
Solution Approach 2:
By creating a composite phosphor mixture with specific weight ratios (yellow 65-85%, red 5-30%, green 5-30%), the patent achieves excellent color rendering properties in a unified material system, eliminating the need for multiple separate conversion layers or complex multi-component packaging structures.
3Stability of the object's composition
If oxygen content in Eu2+ phosphor is increased to improve stability, then the phosphor stability improves, but the red emission intensity decreases
Solution Approach 1:
The patent precisely controls the oxygen content parameter in the Eu2+ active phosphor within the range of 0.1-5.0 wt%. This parameter optimization balances the competing requirements: sufficient oxygen ensures phosphor stability and prevents degradation, while limiting oxygen content maintains strong red emission intensity. The controlled oxygen parameter resolves the contradiction between stability and emission intensity.
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 proposed solution enhances light-emitting efficiency and achieves high CRI and R9 values, addressing the limitations of existing technologies in terms of light emission characteristics and product reliability.
Implementation Method 1
a wavelength conversion portion covering the semiconductor light-emitting device, wherein the wavelength conversion portion includes a transparent encapsulant and a plurality of wavelength conversion materials disposed inside the transparent encapsulant
Implementation Method 2
the plurality of wavelength conversion materials include a green wavelength conversion material, a first red wavelength conversion material, and a second red wavelength conversion material
Data Source
AI summary
A light-emitting device package includes a body portion including a first electrode and a second electrode, a semiconductor light-emitting device on the body portion and emitting blue light, and a wavelength conversion portion covering the semiconductor light-emitting device. The wavelength conversion portion includes a transparent encapsulant and a plurality of wavelength conversion materials inside the transparent encapsulant, the plurality of wavelength conversion materials include a green wavelength conversion material, a first red wavelength conversion material, and a second red wavelength conversion material. The first red wavelength conversion material is a Mn4+ active phosphor. The second red wavelength conversion material is a Eu2+ active phosphor including oxygen of more than about 0 wt % and about 2.4 wt % or less. A weight ratio of the second red wavelength conversion material among the plurality of wavelength conversion materials is about 1 wt % to about 6 wt %.