CaAlSiN3 Phosphor Composition for Red LED Efficiency
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Solution Overview
Problem
Conventional nitride-based phosphors have insufficient light emission efficiency and color rendering properties, leading to poor performance in lighting applications, particularly in image display devices.
Innovation Solution
A phosphor with a specific composition range deviated from the stoichiometric Ca:Al:Si:N ratio, incorporating a controlled amount of solid solution oxygen, and Eu substitution, maintaining the CaAlSiN3 crystal structure, is produced using a nitrogen atmosphere and specific raw material handling to enhance emission efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional nitride-based phosphor (CaAlSiN3) is used, then red light emission is achieved, but light emission efficiency is insufficient
Solution Approach 1:
The patent modifies the stoichiometric composition of CaAlSiN3 by introducing controlled oxygen substitution (CaAl1-x-yS1-zN3-y+zOy) and varying the Si/Al ratio, thereby changing the crystal structure parameters to achieve both higher light emission efficiency and improved color rendering properties simultaneously
Solution Approach 2:
The patent creates a composite phosphor material by combining CaAlSiN3 host lattice with europium activator ions and controlled oxygen substitution, forming a composite structure that achieves both high efficiency red emission and excellent color rendering
2Illumination intensity
If YAG yellow phosphor is used with blue LED, then white light is generated, but red emission component is insufficient
Solution Approach 1:
The patent enhances the red emission component locally by introducing europium-doped CaAlSiN3 phosphor with specific composition ranges (0.7 ≤ x ≤ 1.0, 0.01 ≤ y ≤ 0.3) into the white LED system, providing targeted red wavelength supplementation without affecting the overall brightness
3Use of energy by moving object
If phosphor composition is deviated from stoichiometric ratio, then emission efficiency is improved, but crystal structure stability may be compromised
Solution Approach 1:
The patent optimizes the composition parameters within specific ranges (0.7 ≤ x ≤ 1.0, 0.01 ≤ y ≤ 0.3, Si/Al ratio: 0.9-1.55) to achieve the optimal balance between emission efficiency and crystal structure stability, where the controlled deviations from stoichiometry enhance efficiency while maintaining structural integrity
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 resulting phosphor exhibits higher brightness, improved thermal and chemical stability, and reduced brightness loss at high temperatures, enabling high-efficiency red emission in light emitting devices with enhanced color rendering and longer lifespan.
Implementation Method 1
a phosphor having a host crystal having the same crystal structure as that of a CaAlSiN 3 crystal phase that emits red light by absorbing light from a light emitting element such as LED
Data Source
AI summary
The invention provides a phosphor having a host crystal having the same crystal structure as that of a CaAlSiN3 crystal phase that emits red light by absorbing light from a light emitting element such as LED and having a more improved emission efficiency than ever before, and a light emitting device with high brightness and long life by using the phosphor. The phosphor is represented by a general formula Cax(Si,Al)2 (N, O)3+y, wherein 0.75 ≤ x ≤ 0.92 and -0.2 ≤ y ≤ 0.2, with some of Ca elements substituted with Eu elements, the phosphor being in the form of powder, wherein the phosphor has a Si/Al ratio (molar ratio) of 0.9 or more and 1.55 or less, an Eu content of 0.01 at% or more and 0.3 at% or less, and an amount of solid solution oxygen in particle of 0.4 mass% or more and 0.7 mass% or less.