Fluorescent Material Composition for LED Brightness and Chromaticity
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Solution Overview
Problem
Current white LED light emitting devices using yellow fluorescent materials suffer from insufficient luminous brightness and chromaticity shifts, failing to meet industrial demands for various applications.
Innovation Solution
A fluorescent material with the general formula ((LumA1-m)zCe1-z)3Q5O12, where 0<m<1 and 0<z<1, comprising elements Y, La, Gd, Al, Ga, In, Lu, and Ce, which exhibits improved luminescent properties when excited by a 455 nm light, producing CIE 1931 chromaticity coordinates within specific ranges, and is used in light emitting devices to convert light emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If commercially available yellow fluorescent material (Y,Gd)3(Al,Ga)5O12:Ce is used in white LED devices, then the device can be manufactured with current industrial processes, but the luminous brightness is insufficient and chromaticity shifts occur
Solution Approach 1:
The patent modifies the chemical composition parameters of the fluorescent material by incorporating Lu element and adjusting the molar ratios of A and Q elements according to the formula ((LumA1-m)zCe1-z)3Q5O12 with specific ranges of m and z. This compositional parameter change achieves both enhanced luminous brightness (108% of reference) and stable chromaticity coordinates (x=0.3762, y=0.5722), resolving the contradiction between brightness improvement and chromaticity stability.
Solution Approach 2:
The patent creates a composite fluorescent material by combining multiple rare earth elements (Lu, Ce, A=Y/Gd/La) and metal elements (Q=Al/Ga/In) in specific proportions. This composite approach leverages the complementary properties of each element to achieve superior luminous brightness while maintaining chromaticity stability, overcoming the limitations of conventional single-phase yellow fluorescent materials.
2Illumination intensity
If the luminous brightness of the fluorescent material is increased, then the lighting performance improves, but luminescent chromaticity shift easily occurs
Solution Approach 1:
By precisely controlling the compositional parameters (m and z in the formula ((LumA1-m)zCe1-z)3Q5O12) and sintering conditions, the patent achieves a balanced state where high luminous brightness (108% of reference) is attained without chromaticity shift. The specific parameter ranges defined in the patent ensure both brightness enhancement and chromaticity stability simultaneously.
3Ease of manufacture
If conventional yellow fluorescent materials are used to generate white light, then the manufacturing process is simple, but the luminous brightness remains insufficient for various industrial applications
Solution Approach 1:
The patent maintains manufacturing simplicity by using conventional sintering processes while improving luminous brightness through optimized compositional parameters. The material can be produced using standard ceramic processing techniques, achieving 108% of reference brightness without requiring complex manufacturing equipment or multi-step processes.
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 fluorescent material enhances luminous intensity and maintains desired chromaticity, addressing the brightness and color shift issues in white LED devices, providing a more effective solution for light emitting applications.
Implementation Method 1
Fluorescent materials can absorb and convert lights emitted from semiconductor light emitting elements
Implementation Method 2
the fluorescent material absorbs a blue light emitted from semiconductor light emitting elements and convert it into a yellow light
Data Source
AI summary
A fluorescent material and a light emitting device using the same are provided. The fluorescent material has a general formula of ((LumA1-m)zCe1-z)3Q5O12, wherein 0<m<1 and 0<z<1. A includes at least one of element Y, element La, and element Gd. Q includes at least one of element Al, element Ga, and element In. 1.74≦(m*z+1−z)*3≦3.0 and 0.1≦(1−m)*z*3≦1.35.