Blue LED Light Conversion Using KSF Phosphor to Limit Secondary Absorption
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Solution Overview
Problem
Conventional light emitting devices using quantum dots suffer from secondary absorption, leading to reduced luminous efficiency, particularly in applications requiring brighter light with lower power consumption.
Innovation Solution
Incorporating KSF and MGF phosphors as red phosphors that absorb blue light and emit red light, reducing secondary absorption and enhancing luminous efficiency, while green quantum dots absorb blue light to emit green light, thereby improving light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If red quantum dots are used to emit red light, then color purity is improved, but secondary absorption occurs reducing luminous efficiency
Solution Approach 1:
The patent changes the material parameter from red quantum dots to KSF phosphor (K2SiF6:Mn4+), which has different optical properties. The KSF phosphor absorbs blue light and emits red light without exhibiting secondary absorption of green light, thus maintaining color purity while improving luminous efficiency.
Solution Approach 2:
The patent replaces the expensive and problematic red quantum dots with a more stable and efficient KSF phosphor material, achieving better performance while avoiding the secondary absorption issue that plagues quantum dot-based red emission.
2Measurement precision
If green quantum dots are used to emit green light, then emission peak sharpness is improved, but secondary absorption by red quantum dots reduces overall efficiency
Solution Approach 1:
The patent extracts the problematic red quantum dots from the system and replaces them with KSF phosphor. This removal eliminates the secondary absorption of green light while preserving the sharp emission peak characteristics of green quantum dots, as the green quantum dots can now emit without being re-absorbed by red converters.
3Illumination intensity
If conventional phosphors are used, then broad emission peaks are achieved, but light extraction efficiency through color filters is reduced
Solution Approach 1:
The patent creates a composite light emitting device combining green quantum dots (for sharp green emission) with KSF phosphor (for red emission without secondary absorption). This composite approach leverages the advantages of both quantum dots (sharp peaks) and phosphors (stable emission), achieving high light extraction efficiency through better matching with color filter transmission characteristics.
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 use of KSF and MGF phosphors in light emitting devices minimizes secondary absorption, resulting in high luminous efficiency and red light with high color purity, suitable for applications like liquid crystal displays and illumination.
Implementation Method 1
a light emitting element that emits a blue light
Implementation Method 2
quantum dots that emit a green light by absorbing part of the blue light emitted from the light emitting element
Implementation Method 3
at least one of a KSF phosphor and a MGF phosphor, wherein the KSF phosphor is a compound having the chemical formula A2[M1-aMn4+aF6] (1)... adapted to absorb at least a portion of the blue light emitted from the light emitting element to emit red line
Data Source
AI summary
A light emitting device includes a light emitting element adapted to emit blue light, quantum dots that absorb part of the blue light emitted from the light emitting element to emit green light, and at least one of a KSF phosphor adapted to absorb part of the blue light emitted from the light emitting element to emit red light and a MGF phosphor adapted to absorb part of the blue light emitted from the light emitting element to emit red light.