Rare Earth Aluminate Phosphor Composition for Luminescence Efficiency
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Solution Overview
Problem
Existing rare earth aluminate phosphors used in light emitting devices and projectors face challenges in achieving high luminescence efficiency and optimal reflectance ratios, which affect their performance in wavelength conversion applications.
Innovation Solution
A rare earth aluminate phosphor with a specific composition including elements such as yttrium, lanthanum, lutetium, cerium, aluminum, and optionally gallium or scandium, is developed. This phosphor has a tailored molecular ratio and reflection spectrum, allowing for enhanced luminescence efficiency when used in wavelength conversion members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If existing rare earth aluminate phosphors are used in light emitting devices, then basic luminescence function is achieved, but luminescence efficiency is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the phosphor by incorporating gallium or scandium elements alongside rare earth elements (yttrium, lutetium, gadolinium) and cerium activators. This compositional parameter modification optimizes the crystal structure and electronic properties, resulting in enhanced luminescence efficiency and reduced energy loss in wavelength conversion applications
Solution Approach 2:
The patent creates a composite phosphor material combining multiple rare earth elements (Y, Lu, Gd) with aluminum, gallium/scandium, and cerium activators. This composite approach leverages the synergistic effects of different elements to achieve superior luminescence properties compared to single-element phosphors, directly addressing the efficiency limitation
2Reliability
If conventional phosphor composition is used, then manufacturing simplicity is maintained, but reflectance ratio performance is insufficient
Solution Approach 1:
The patent specifies precise compositional parameters (molar ratios of rare earth elements, aluminum, gallium/scandium, and cerium content) to achieve the target reflectance ratio of 0.33-0.76. By controlling these chemical parameters, the phosphor achieves improved optical performance while maintaining a manageable compositional structure suitable for manufacturing
3Productivity
If high luminescence efficiency is achieved through composition optimization, then wavelength conversion performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific molar ratio ranges for each element (rare earth elements: 2.9-3.1, aluminum + gallium/scandium: 4.5-5.5 when oxygen is 12 moles) to achieve optimal wavelength conversion efficiency. These parameter specifications balance the need for high performance with practical manufacturing capabilities, providing clear targets for production control
Solution Approach 2:
The patent introduces optional local modification by allowing gallium or scandium substitution at specific compositional positions. This localized compositional adjustment enables fine-tuning of optical properties without requiring complete redesign of the entire phosphor system, facilitating incremental optimization with manageable precision requirements
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 developed rare earth aluminate phosphor achieves high luminescence efficiency and improved reflectance ratios, leading to enhanced performance in light emitting devices and projectors, particularly in wavelength conversion applications.
Implementation Method 1
Ce-activated rare earth aluminate phosphors emit yellow to green light when excited by irradiation of particle rays such as electron beams, vacuum ultraviolet rays, and blue light
Implementation Method 2
Ce-activated rare earth aluminate phosphors emit yellow to green light when excited by irradiation of particle rays such as electron beams, vacuum ultraviolet rays, and blue light
Implementation Method 3
the rare earth aluminate phosphor has a reflection spectrum in which a ratio of reflectance at a wavelength of 280 nm to reflectance at a wavelength of 380 nm is 0.33 or more and 0.76 or less
Implementation Method 4
subjecting the first rare earth aluminate to a first heat treatment at a temperature of 900° C. or higher and lower than 1300° C. in a reducing atmosphere
Data Source
AI summary
A rare earth aluminate phosphor includes: a first element M1 including at least one selected from the group consisting of yttrium (Y), lanthanum (La), lutetium (Lu), gadolinium (Gd), and terbium (Tb); cerium (Ce); aluminum (Al); oxygen atoms (O) and optionally a second element M2 including at least one selected from the group consisting of gallium (Ga) and scandium (Sc). The rare earth aluminate phosphor has a composition in which when a number of moles of oxygen atoms is 12, a total number of moles of the first element M1 and cerium is 2.9 or more and 3.1 or less, and a total number of moles of aluminum and the second element M2 is 4.5 or more and 5.5 or less, and has a reflection spectrum in which a ratio of reflectance at a wavelength of 280 nm to reflectance at a wavelength of 380 nm is 0.33 or more and 0.76 or less.