Beta-sialon Phosphor Eu Doping for Fluorescence Peak Intensity
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Solution Overview
Problem
Existing β-sialon phosphors used in light emitting devices have limitations in achieving high peak intensity in fluorescence measurements, leading to lower light emission efficiency and brightness in applications such as LEDs, image displays, and illuminating apparatuses.
Innovation Solution
A β-sialon with the general formula Si6-zAlzOzN8-z:Eu, where P2/P1 is between 0.5 and 1000, and the Eu content is between 0.1% and 3% by mass, optimized through electron spin resonance techniques to enhance fluorescence emission, is used in light emitting devices, image displays, and illuminating apparatuses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional β-sialon phosphors are used in light emitting devices, then the device structure is simple and manufacturing is easy, but the peak intensity in fluorescence measurement is insufficient and light emission brightness is low
Solution Approach 1:
The invention optimizes specific parameters of the β-sialon phosphor: Eu content (0.1-3% by mass) and P2/P1 ratio (0.5-1000 in ESR spectrum). By precisely controlling these parameters, the phosphor achieves enhanced fluorescence peak intensity and improved light emission brightness without fundamentally changing the device structure or manufacturing process
Solution Approach 2:
The invention focuses on improving the local quality of the phosphor material by optimizing the Eu doping concentration and the P2/P1 ratio in the electron spin resonance spectrum. This targeted optimization of specific material properties enhances the fluorescence characteristics while maintaining overall manufacturing simplicity
2Illumination intensity
If Eu content is increased to enhance fluorescence emission, then peak intensity improves, but manufacturing precision requirements increase to control the P2/P1 ratio
Solution Approach 1:
The invention establishes specific parameter ranges: Eu content of 0.1-3% by mass and P2/P1 ratio of 0.5-1000. These defined ranges provide clear manufacturing targets that balance fluorescence enhancement with achievable production precision, avoiding the need for extremely tight tolerances while still achieving high peak intensity
Solution Approach 2:
The invention uses electron spin resonance (ESR) spectroscopy to measure the P2/P1 ratio as a feedback parameter to monitor and control the phosphor quality. This measurement technique provides a non-destructive method to verify that the Eu content and structural properties are within the optimal ranges for high fluorescence emission
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 optimized β-sialon phosphor achieves higher peak intensity in fluorescence measurements, resulting in brighter light emission and improved color rendering properties in light emitting devices, image displays, and illuminating apparatuses.
Implementation Method 1
the Eu2+ is excited by ultraviolet-blue light. This phosphor emits green-yellow light
Implementation Method 2
the Eu2+ is excited by ultraviolet-blue light
Implementation Method 3
the spin density corresponding to an absorption line appearing in the region where g is 2.00±0.02 in the electron spin resonance spectrum of the β-sialon at 25° C.
Data Source
AI summary
An object of the present invention is to provide a phosphor that is combined with a blue LED to achieve white light at a low color temperature as if singly, has a broad fluorescence spectrum for excellent color rendering properties, has a high luminous efficiency, is thermally and chemically stable like conventional nitride-based phosphors, and has a small decrease in luminance at high temperatures. Another object of the present invention is to provide a light emitting device using such a phosphor. The present invention relates to a β-sialon that is expressed by the general formula, Si6-zAlzOzN8-z:Eu (0<z<4.2). In the β-sialon, P2/P1 is not lower than 0.5 and not higher than 1000 (P1 representing the height of an absorption line appearing in the region where g is 2.00±0.02 in a first derivative spectrum obtained by an electron spin resonance technique at 25° C., P2 representing the difference between the maximum value and the minimum value in a spectrum on the lower magnetic field side of P1).