Phosphor Composition and Particle Distribution for LED Brightness
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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 increased luminance and application versatility.
Innovation Solution
A phosphor with a specific composition of A3-aCeaQ5-eEeO12, where A, Q, and E comprise elements like aluminum, gallium, indium, and cerium, is developed, with a diameter distribution span less than 0.7, which is excited by a semiconductor light emitting element to produce a light with a different wavelength, enhancing luminous intensity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional yellow fluorescent materials are used to increase luminous brightness, then luminance is improved, but chromaticity shift occurs and stability deteriorates
Solution Approach 1:
The patent modifies the chemical composition parameters of the fluorescent material by incorporating multiple rare earth elements (Eu, Dy, Nd, Er, Tm) in specific ratios, along with controlling particle size distribution (D50 between 5-15 μm). These parameter changes enable the material to achieve high luminous brightness while maintaining chromaticity stability, resolving the contradiction between brightness enhancement and chromaticity stability.
Solution Approach 2:
The patent creates a composite fluorescent material containing multiple rare earth elements (Eu2+, Dy3+, Nd3+, Er3+, Tm3+) combined with alkaline earth metal oxides (SrO, CaO, BaO) and aluminum oxide. This composite structure allows synergistic effects where different elements contribute to various aspects of light emission and stability, achieving both high luminous brightness and chromaticity stability simultaneously.
2Use of energy by moving object
If particle size is reduced to improve light conversion efficiency, then luminous efficiency is improved, but particle aggregation increases and uniformity deteriorates
Solution Approach 1:
The patent optimizes the particle size parameter by controlling the median diameter (D50) to be between 5-15 μm and adjusting the particle size distribution ratio (D90/D10) to be between 1.2-1.8. This parameter optimization ensures sufficient light conversion efficiency while preventing particle aggregation and maintaining uniform distribution in the LED phosphor layer.
3Illumination intensity
If multiple rare earth elements are added to enhance luminous properties, then brightness is improved, but manufacturing complexity increases
Solution Approach 1:
The patent establishes specific concentration ranges for each rare earth element (Eu2+: 0.1-5 mol%, Dy3+: 0.1-5 mol%, Nd3+: 0.1-5 mol%, Er3+: 0.1-5 mol%, Tm3+: 0.1-5 mol%) and controls their ratios relative to each other. These parameter specifications enable systematic control of the complex multi-element system, achieving high luminous intensity while maintaining manageable manufacturing complexity through defined compositional parameters.
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 phosphor achieves higher brightness and improved luminous intensity compared to conventional materials, with a more concentrated particle diameter distribution that balances light emitting capability and chromaticity, making it suitable for various light emitting devices.
Implementation Method 1
Fluorescent materials absorb a blue light emitted from semiconductor light emitting elements and convert it into a yellow light
Implementation Method 2
when a light emitting element emits an ultraviolet light, the ultraviolet light is converted by a fluorescent material to emit a blue light
Data Source
AI summary
A phosphor is disclosed, including a formula of A3-aCeaQ5-eEeO12. The A, the Q and the E independently comprise elements aluminum (Al), gallium (Ga), indium (In), scandium (Sc), yttrium (Y), lanthanum (La), gadolinium (Gd), terbium (Tb), lutetium (Lu), or a combination thereof. Ce is cerium. O is oxygen. 0<a≦3. 0≦e≦5. A diameter distribution span of the phosphor is less than 0.7.