β-SiAlON Phosphor Density Control for Stable White LED Chromaticity
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Solution Overview
Problem
Light-emitting apparatuses, such as backlights and liquid crystal displays, require improved light-emitting characteristics and production accuracy to reduce variations in chromaticity among LED products.
Innovation Solution
A β-sialon phosphor with a bulk density between 0.80 g/cm3 and 1.60 g/cm3, combined with a semiconductor light-emitting element, is used to stabilize light-emitting characteristics and minimize chromaticity variations in white LEDs by controlling the phosphor's bulk density, grain size distribution, and surface state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional β-sialon phosphors are used without controlling bulk density, then production is simpler, but variation in chromaticity among LED products increases
Solution Approach 1:
The patent applies parameter changes by establishing a specific bulk density range (0.60-1.80 g/cm³) for β-sialon phosphor particles. This controlled parameter range directly addresses the chromaticity variation problem while maintaining manageable production complexity through clear specification limits.
2Reliability
If bulk density of β-sialon phosphor is controlled within specified range, then chromaticity variation is suppressed, but production process becomes more complex
Solution Approach 1:
The patent controls the bulk density parameter within a specific range (0.60-1.80 g/cm³) to ensure stable light-emitting characteristics and suppress chromaticity variation. This parameter control approach improves reliability while maintaining ease of manufacture through well-defined specification limits.
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 β-sialon phosphor effectively reduces variations in chromaticity and enhances the stability of light-emitting characteristics in white LEDs, leading to improved performance in illumination and image display applications.
Implementation Method 1
β-sialon, when contains europium (Eu2+) in a crystal structure thereof, is excited by ultraviolet to blue light and serves as a phosphor that exhibits green light emission at 520 to 550 nm
Data Source
AI summary
A β-sialon phosphor represented by general formula: Si6-zAlzOzN8-z (0<z<4.2) has as a host crystal, a crystal structure identical to that of a β-sialon crystal phase and having a bulk density of 0.80 g/cm3 or more and 1.60 g/cm3 or less. Also, a light-emitting element includes the β-sialon phosphor and a semiconductor light-emitting element capable of exciting the β-sialon phosphor.