Excimer Lamp Phosphor Protection via Spatial Segmentation
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Solution Overview
Problem
Existing excimer lamps face challenges in efficiently generating VUV radiation and converting it to longer wavelengths using phosphors without degrading the phosphors due to high energy ions or electrons, which limits their lifetime and efficiency.
Innovation Solution
The solution involves forming excimers within a chamber containing an excimer-forming gas and a phosphor, where energetic free electrons are provided to produce radiation that impinges on the phosphor, with the phosphor disposed outside the region of high-energy electron activity, thus protecting it from degradation and allowing efficient conversion of VUV radiation to longer wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If phosphor is included within the electric field region or electron beam path to produce longer wavelength radiation, then the lamp can convert VUV radiation to visible light, but the phosphor degrades due to high energy electron or ion bombardment
Solution Approach 1:
The lamp is divided into two distinct regions: an excimer generation region where high energy electrons are produced, and a phosphor conversion region where lower energy electrons convert VUV to visible light. This spatial segmentation protects the phosphor from degrading high energy electron bombardment while maintaining wavelength conversion functionality.
Solution Approach 2:
A magnetic field is introduced as an intermediary component to selectively guide and filter electrons. The magnetic field allows lower energy electrons to reach the phosphor for wavelength conversion while blocking higher energy electrons that would cause phosphor degradation, thus mediating the interaction between electrons and phosphor.
2Productivity
If DBD excimer lamp operates at high power to generate VUV radiation, then radiation efficiency is improved, but heat and high energy ions degrade the phosphor
Solution Approach 1:
The harmful high energy ions and excessive heat are extracted or removed from the phosphor region through optimized electrode configuration and dielectric barrier design. The excimer generation is confined to a region separated from the phosphor, allowing VUV radiation to reach the phosphor while excluding the harmful byproducts.
Solution Approach 2:
Different regions of the lamp are assigned different functional qualities: the excimer generation region operates at high power with dielectric barriers to maximize VUV production, while the phosphor region maintains lower energy conditions suitable for stable wavelength conversion. This local differentiation allows both high productivity and phosphor protection.
3Productivity
If mercury discharge lamp is used to generate UV radiation, then lighting efficiency is achieved, but mercury release harms the environment and degrades phosphors
Solution Approach 1:
The lamp uses an inert excimer-forming gas (such as xenon or krypton mixed with fluorine-containing gas) instead of reactive mercury vapor. This inert atmosphere eliminates environmental contamination risks and prevents phosphor degradation from mercury reactivity while maintaining efficient UV/VUV radiation generation through excimer formation and decay.
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
This approach effectively extends the lifespan of the phosphor and maintains high efficiency by preventing degradation from high-energy electron bombardment, while ensuring efficient conversion of VUV radiation to visible or longer UV light.
Implementation Method 1
providing energetic free electrons in the gas, so that the excimers produce radiation
Implementation Method 2
the phosphor converts the radiation produced by the excimers to light at a wavelength different from a wavelength of the radiation produced by the excimers
Data Source
AI summary
Excimers are formed in a high pressure gas by applying a potential between a first electrode (14, 214) and a counter electrode (25, 226) so as to impose an electric field within the gas, or by introducing high energy electrons into the gas using an electron beam. A phosphor for converting the wavelength of radiation emitted from the formed excimers is disposed within the gas and outside a region (62, 162) where the excimers are expected to be formed, so as to avoid degradation of the phosphor.