LSN Phosphor Composition for Blue LED Efficiency
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Solution Overview
Problem
Existing phosphors, such as oxide-based silicates and garnet-based YAG, face challenges in maintaining high light emission efficiency, especially at high temperatures and with blue light excitation, and nitride-based LSN phosphors require improved efficiency for commercial applications.
Innovation Solution
A phosphor composition with a rare-earth element or manganese in a La3Si6N11 mother compound, formed into particles with specific crystal plane orientations, enhances light emission efficiency and reliability, particularly when used in white LED devices with blue or ultraviolet light excitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If oxide-based phosphor (silicate) is used with blue light excitation, then the device structure is simple, but light emission strength decreases when excitation wavelength exceeds 400 nm
Solution Approach 1:
The patent changes the chemical composition parameters of the phosphor material by substituting elements in the LSN structure (replacing La with Y, Gd, or Lu; replacing Si with Al or Ga) to optimize light emission efficiency for blue light excitation while maintaining structural simplicity
Solution Approach 2:
The patent creates composite phosphor materials by combining LSN base structure with rare-earth element dopants (Ce, Eu, Tb, etc.) to achieve both high light emission efficiency and suitable device structure for blue LED excitation
2Illumination intensity
If garnet-based YAG phosphor is used, then excellent excitation efficiency and light emission efficiency are provided, but light emitting efficiency at high temperature is reduced
Solution Approach 1:
The patent modifies the chemical composition parameters of the phosphor by using LSN base structure with specific rare-earth element dopants to achieve both high excitation efficiency and high-temperature stability, resolving the trade-off between efficiency and thermal reliability
Solution Approach 2:
The patent introduces specific rare-earth element dopants at controlled concentrations into the LSN structure to locally enhance excitation efficiency while the overall LSN matrix maintains high-temperature stability
3Reliability
If LSN phosphor is used, then high temperature characteristics and reliability are improved, but light emission efficiency needs improvement for commercial applications
Solution Approach 1:
The patent optimizes the compositional parameters of LSN phosphor by substituting La with Y, Gd, or Lu and Si with Al or Ga, and by controlling rare-earth element dopant concentrations to simultaneously achieve high light emission efficiency and maintain high-temperature reliability for commercial applications
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 phosphor composition significantly increases light emission efficiency by up to 7% and maintains high reliability, making it suitable for high-temperature applications and efficient wavelength conversion in white light emitting devices.
Implementation Method 1
a phosphor converting a light wavelength to visible light by using light emitted from the light emitting device as an excitation source
Implementation Method 2
a portion of blue light incident on and absorbed by phosphors in the phosphor layer during this process
Data Source
AI summary
There are provided a phosphor and a light emitting device. The phosphor includes a phosphor composition including a rare-earth element employed in a compound represented by the equation: L3Si6N11, wherein L is one or more elements selected from La, Y, Gd and Lu, the rare-earth element is one or more elements selected from Mn, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Tb, Ho, Er, Tm and Yb. The phosphor composition is provided in particle form. The particle has at least a portion of a plane perpendicular to a [001] direction to be flat thereon so as to have a crystal plane.