Oxynitride Phosphor JEM Phase for Blue Light Emission
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Solution Overview
Problem
There is a lack of phosphors that efficiently emit light in the blue to bluish purple range with high stability and emission efficiency, particularly for semiconductor light-emitting devices using excitation wavelengths between 390 nm and 420 nm.
Innovation Solution
An oxynitride phosphor with a JEM phase, composed of elements like La, Ce, Si, Al, O, and N, is developed, which can be excited by light in this wavelength range and emits light efficiently, with a specific composition formula M1−aCeaSibAlcOdNe, containing 50% or more JEM phase, and an emission peak wavelength of 460 nm or more and 510 nm or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing sialon phosphors are used, then the device can emit blue to bluish purple light, but the emission efficiency and stability are insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the phosphor material by introducing oxygen into the sialon structure to create oxynitride phosphor. This compositional parameter change results in improved emission efficiency and stability while maintaining the blue to bluish purple emission range, directly resolving the technical contradiction between reliability and energy loss.
2Loss of energy
If phosphors are excited by light in the 390 nm to 420 nm wavelength range, then the phosphor can convert the wavelength to visible light, but there is a lack of phosphors with sufficient emission efficiency and stability in this range
Solution Approach 1:
The patent develops a composite oxynitride phosphor material that combines multiple elements (La, Ce, Si, Al, O, N) in specific ratios. This composite material structure enables the phosphor to efficiently absorb ultraviolet light in the 390-420 nm range and convert it to blue to bluish purple visible light with high emission efficiency and improved stability, resolving the contradiction between emission efficiency and stability for this specific excitation wavelength range.
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 oxynitride phosphor exhibits higher brightness and stability compared to existing sialon phosphors, with improved emission efficiency and reduced material deterioration when excited, making it suitable for semiconductor light-emitting devices.
Implementation Method 1
a first phosphor that is excited by light emitted from the semiconductor light-emitting element and has an emission peak wavelength of 460 nm or more and 510 nm or less
Data Source
AI summary
The invention provides an oxynitride phosphor represented by a composition formula M1−aCeaSibAlcOdNe, wherein M denotes La or a compound of which main component is La and sub-component is at least one kind of element selected from the group consisting of Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb and Lu; the a that represents a composition ratio of Ce is a real number satisfying 0.1≦a≦1; the b that represents a composition ratio of Si is a real number satisfying b=(6−z)×f; the c that represents a composition ratio of Al is a real number satisfying c=(1+z)×g; the d that represents a composition ratio of O is a real number satisfying d=z×h; the e that represents a composition ratio of N is a real number satisfying e=(10−z)×i; the z is a real number satisfying 0.1≦z≦3; the f is a real number satisfying 0.7≦f≦1.3; the g is a real number satisfying 0.7≦g≦3; the h is a real number satisfying 0.7≦h≦3; the i is a real number satisfying 0.7≦i≦1.3; and a JEM phase is contained in an amount of 50% or more, and a semiconductor light-emitting device that uses the oxynitride phosphor.