Hexagonal Phosphor Composition for LED Emission Efficiency
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Solution Overview
Problem
Current yellow and orange phosphors used in white light-emitting LEDs do not meet the demand for improved emission characteristics, necessitating the development of a new phosphor with enhanced performance for LED applications.
Innovation Solution
A new phosphor with a hexagonal crystal system, comprising specific compositions and elements such as europium, alkaline earth metals, and silicon, which emits light in the yellow to orange spectrum with improved emission efficiency and temperature stability, is developed. This phosphor is integrated into light-emitting devices, illumination devices, and image display devices to enhance their performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional yellow or orange phosphors (YAG, α-sialon) are used in white light-emitting LEDs, then the basic illumination function is achieved, but the emission efficiency and emission characteristics are insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the phosphor by incorporating specific ratios of Sr, Ca, Al, Si, and N elements to create a new phosphor compound with improved emission efficiency and characteristics. The compositional formula Sr3-x-yCaxAlySi24N40:Eu2+ with specific ranges of x, y, and z parameters optimizes the emission properties while maintaining structural stability.
Solution Approach 2:
The patent creates a composite phosphor material by combining multiple elements (Sr, Ca, Al, Si, N) in a specific crystalline structure, resulting in a composite compound that exhibits superior emission characteristics compared to conventional single-element phosphors like YAG or α-sialon.
2Illumination intensity
If existing phosphor compositions are used, then manufacturing simplicity is maintained, but emission characteristics and color reproduction range are limited
Solution Approach 1:
The patent optimizes the compositional parameters within a systematic framework (Sr3-x-yCaxAlySi24N40:Eu2+), allowing for controlled variation of elements to achieve desired color reproduction while maintaining a consistent crystal structure that simplifies the manufacturing process.
3Duration of action of stationary object
If conventional phosphors are used, then device simplicity is maintained, but temperature stability of emission intensity is insufficient
Solution Approach 1:
The patent develops a composite phosphor material with a specific crystalline structure containing Sr, Ca, Al, Si, and N elements that provides enhanced thermal stability, allowing the phosphor to maintain consistent emission intensity across a wide temperature range from -30°C to 85°C.
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 new phosphor provides improved emission characteristics, including a broader color reproduction range and higher emission efficiency, maintaining intensity even at elevated temperatures, resulting in high-quality light-emitting devices and illumination systems.
Implementation Method 1
a phosphor, which emits yellow or orange light using the blue light from the blue LED chip as an excitation light
Data Source
AI summary
A phosphor comprising a crystalline phase having a composition expressed by Formula [1] below, a crystal system of the phosphor being a hexagonal crystal system,MmAaAlbSicN40 [1](in Formula [1]M denotes an activating element,A denotes one or more types of elements selected from the group consisting of alkaline earth metal elements, andm, a, b and c denote values that satisfy expressions below independent from each other0<m≤0.21.2≤a≤5.62.4≤b≤11.218.8≤c≤27.6).