PC Red LED Phosphor Structure for Color Purity and Moisture Protection
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Solution Overview
Problem
Current PC Red LEDs using narrowband red fluoride phosphors face challenges such as high cost, low absorption efficiency, and susceptibility to moisture, leading to reduced color purity and device reliability due to 'blue pass through' and chemical reactivity.
Innovation Solution
Incorporating a broadband red phosphor with higher absorption efficiency alongside narrowband red fluoride phosphor, either in a single or double-layer structure, to enhance blue light conversion and protect the fluoride phosphor from moisture, reducing its usage and improving color purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If narrowband red fluoride phosphor is used in PC Red LEDs, then color purity is improved, but absorption efficiency deteriorates and cost increases
Solution Approach 1:
The patent combines narrowband red fluoride phosphor with broadband red phosphor to create a composite phosphor system. The narrowband component provides high color purity while the broadband component ensures efficient blue light absorption, resolving the contradiction between color purity and absorption efficiency
Solution Approach 2:
The patent adjusts the emission peak wavelength of the narrowband red fluoride phosphor to be within 15 nm of the dominant wavelength of the red light, and optimizes the ratio of narrowband to broadband phosphor materials. These parameter changes enable the system to achieve both high absorption efficiency and high color purity
2Measurement precision
If narrowband red fluoride phosphor is used, then color purity is improved, but device reliability deteriorates due to moisture susceptibility
Solution Approach 1:
The patent introduces an intermediary encapsulant layer between the narrowband red fluoride phosphor and the external environment. This encapsulant protects the moisture-sensitive fluoride phosphor from chemical reactions while allowing the phosphor to maintain its high color purity emission characteristics
Solution Approach 2:
The patent extracts the narrowband red fluoride phosphor from direct exposure to moisture by separating it into a protected configuration, thereby eliminating the harmful interaction between moisture and the fluoride phosphor while preserving its optical performance
3Measurement precision
If narrowband red fluoride phosphor is used, then color purity is improved, but manufacturing cost increases
Solution Approach 1:
The patent optimizes the ratio of narrowband to broadband phosphor materials and adjusts the emission peak wavelength parameters to achieve high color purity while using a cost-effective combination of phosphors, thereby reducing manufacturing cost
Solution Approach 2:
The patent replaces expensive narrowband red fluoride phosphor in bulk usage with a optimized combination where a smaller amount of narrowband phosphor is combined with more economical broadband phosphor, achieving similar color purity at lower cost
4Use of energy by moving object
If broadband red phosphor is added to enhance absorption efficiency, then absorption efficiency is improved, but device complexity increases
Solution Approach 1:
The patent merges the narrowband red fluoride phosphor and broadband red phosphor into a single integrated phosphor layer or closely positioned layers, simplifying the device structure while achieving both high absorption efficiency and high color purity
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 achieves red light with high color purity and reduced 'blue pass through', lowering manufacturing costs and enhancing device reliability by optimizing phosphor usage and protection.
Implementation Method 1
a photoluminescence material, wherein the photoluminescence material comprises a narrowband red fluoride phosphor and a broadband red phosphor
Data Source
AI summary
A light emitting device comprising a Phosphor-Converted LED for generating red light: wherein the Phosphor-Converted LED comprises: a blue LED; and a narrowband red fluoride phosphor.