Phosphate Phosphor Deep Ultraviolet Emission
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Solution Overview
Problem
Conventional mercury-free ultraviolet light emitting phosphors do not achieve sufficient emission intensity in the ultraviolet region, particularly for sterilization applications, with most emitting in the near ultraviolet or blue region and not reaching wavelengths shorter than 310 nm.
Innovation Solution
A phosphate phosphor composed of at least two metal elements selected from group 13 elements and lanthanoid series elements, excited by vacuum ultraviolet rays or electron beams, which emits intense ultraviolet light across the 190 nm to 340 nm range, suitable for applications like sterilization and ozone generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional phosphors (YAlO3:Ce3+, spinel type phosphors, or simple phosphates like ScPO4) are used for vacuum ultraviolet excitation, then the light source can be mercury-free and structurally simple, but the emission intensity in the deep ultraviolet region (wavelength shorter than 310 nm) is insufficient
Solution Approach 1:
The patent employs composite phosphor materials combining multiple metal elements (Sc, Lu, Y, La, Al) in specific ratios within a phosphate matrix. This composite approach enables the phosphor to achieve high emission intensity in the deep ultraviolet region (190-310 nm) when excited by vacuum ultraviolet light, while maintaining structural stability and mercury-free operation. The synergistic effect of multiple elements in the composite structure resolves the contradiction between emission intensity and compositional simplicity.
Solution Approach 2:
The patent systematically optimizes the compositional parameters of the phosphor, specifically the molar ratios of Sc (0.1-0.5), Lu (0.3-0.8), Y (0.05-0.2), La (0.05-0.2), and Al (0.05-0.2), along with the phosphate content (0.7-0.95). By precisely controlling these parameters, the phosphor achieves peak emission intensity in the deep ultraviolet region while maintaining structural stability, thus resolving the contradiction between high emission intensity and compositional complexity.
2Illumination intensity
If phosphors emitting in near ultraviolet or blue region (370 nm peak wavelength) are used, then the phosphor structure can be simpler, but the wavelength is not suitable for sterilization applications requiring deep ultraviolet emission
Solution Approach 1:
The patent precisely controls the compositional parameters to shift the emission peak from near ultraviolet/blue region (370 nm) to deep ultraviolet region (190-310 nm). The specific molar ratios of Sc (0.1-0.5), Lu (0.3-0.8), Y (0.05-0.2), La (0.05-0.2), and Al (0.05-0.2) are optimized to achieve the desired wavelength shift while maintaining manufacturing feasibility. This parameter optimization resolves the contradiction between achieving suitable sterilization wavelength and maintaining manufacturing precision.
Solution Approach 2:
The patent introduces specific metal elements (Sc, Lu, Y, La, Al) at controlled concentrations within the phosphate matrix to create localized emission centers that preferentially emit in the deep ultraviolet region. This local quality modification within the phosphor structure enables wavelength-specific emission for sterilization applications while maintaining overall compositional stability, resolving the contradiction between wavelength precision and manufacturing complexity.
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 phosphate phosphor exhibits significantly higher emission intensity in the deep ultraviolet region, making it suitable for various applications including sterilization, organic matter decomposition, and ozone generation, while being mercury-free.
Implementation Method 1
a phosphor composed of a phosphate containing at least two metal elements selected from the group consisting of group 13 elements and lanthanoid series elements, and the phosphor is excited to emit ultraviolet by irradiation with vacuum ultraviolet rays or electron beam
Implementation Method 2
a phosphor composed of a phosphate containing at least two metal elements selected from the group consisting of group 13 elements and lanthanoid series elements, and the phosphor is excited to emit ultraviolet by irradiation with vacuum ultraviolet rays or electron beam
Data Source
AI summary
An ultraviolet light emitting phosphor for mercury-free lamps is a phosphor composed of a phosphate containing at least two metal elements selected from the group consisting of group 13 elements and lanthanoid series elements, and is excited to emit ultraviolet by irradiation with vacuum ultraviolet rays or an electron beam.