UVC Excimer Discharge Device Phosphor Composition
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Solution Overview
Problem
Existing UV-emitting devices for disinfection and purification have suboptimal optical efficiency for germicidal applications, particularly in the UV-C range, which is crucial for effectively deactivating pathogens.
Innovation Solution
A device utilizing an excimer discharge with a UV-transparent discharge vessel filled with a gas and coated with a phosphor containing a host lattice of (Y1-x-y-z,Lux,Scy,Az)PO4, where A is bismuth, praseodymium, or neodymium, optimized to emit radiation between 225 and 275 nm, enhancing germicidal effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional phosphors are used in UV-emitting devices, then the device can emit UV radiation, but the optical efficiency for germicidal applications is suboptimal
Solution Approach 1:
The patent applies parameter changes by optimizing the phosphor composition with specific ratios of Y, Lu, Sc, and A (Bi, Pr, or Nd) in the host lattice (Y1-x-y-z,Lux,Scy,Az)PO4. This compositional parameter optimization shifts the emission spectrum to maximize overlap with the germicidal action curve (250-260 nm peak), thereby improving both optical efficiency and germicidal effectiveness simultaneously.
Solution Approach 2:
The patent uses composite phosphor materials combining multiple rare earth elements (Y, Lu, Sc) with activator elements (Bi, Pr, or Nd) in a phosphate host lattice. This composite structure enables tailored emission spectra that achieve superior germicidal efficiency by concentrating radiation in the 225-275 nm range where microorganisms show maximum sensitivity.
2Reliability
If the emission bandwidth is narrowed to match the germicidal peak, then germicidal effectiveness improves, but the bandwidth becomes too narrow for broader applications
Solution Approach 1:
The patent optimizes the emission spectrum parameters by adjusting the phosphor composition to achieve a balanced bandwidth. The composition (Y1-x-y-z,Lux,Scy,Az)PO4 with specific x, y, z values controls both the peak position (250-260 nm) and the bandwidth, ensuring maximum germicidal effectiveness while maintaining sufficient spectral width for various photodisinfection and photolytic applications.
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 device achieves higher photon energy and broader bandwidth emission, improving germicidal efficiency by aligning with the germicidal action curve, suitable for photodisinfection and photolytic processes, with enhanced durability and low temperature dependence.
Implementation Method 1
means for triggering and maintaining an excimer discharge in the discharge space
Implementation Method 2
a luminescent material that contains a UV-C emitting phosphor
Implementation Method 3
UV light, and in particular, UV-C light is 'germicidal' i.e., it deactivates the DNA of bacteria, viruses and other pathogens
Data Source
AI summary
A device for generating ultraviolet radiation by an excimer discharge includes at least partly UV-transparent discharge vessel whose discharge space is filled with a gas filling. The device further includes electrodes for triggering and maintaining an excimer discharge in the discharge space, and a luminescent material that contains a phosphor comprising a host lattice of general formula (Y1-x-y-z,Lux,Scy,Az)PO4 wherein 0≦x<1 and 0<y≦1 and 0≦z<0.05, where A is an activator selected from the group of bismuth, praseodymium and neodymium.