Thin Wire Inner Electrode for VUV Excimer Lamp Efficiency

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Solution Overview

Problem

Existing VUV excimer lamps have low wall plug efficiencies and short lifespans, and are prone to arcing when power density is exceeded.

Innovation Solution

A VUV excimer lamp design featuring a dielectric tube with a thin, elongated electrode (outer diameter < 0.5 mm) and a second electrode in a tape, wire, or mesh form, filled with high-purity Xenon gas at optimized pressure, which improves efficiency and extends lifespan by homogenizing the discharge and reducing radiation absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional thick inner electrode is used in the excimer lamp, then the structural strength and ease of manufacture are improved, but the wall plug efficiency is low and the lifespan is short

Engineering Contradiction:
Improveease of manufactureVSAvoidwall plug efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent applies parameter changes by reducing the outer diameter of the inner electrode from conventional dimensions to less than 0.5 mm (specifically 0.02-0.4 mm). This parameter change optimizes the electric field distribution and electron multiplication within the discharge chamber, resulting in significantly improved wall plug efficiency while maintaining structural integrity through the specific geometric ratio (R/ro)/ln(R/ro) > 8

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by creating a specific geometric configuration where the thin wire electrode (with outer diameter < 0.5 mm) is positioned at a precise distance from the dielectric tube wall. The local geometry is optimized such that (R/ro)/ln(R/ro) > 8, where R is the inner radius of the dielectric tube and ro is the outer radius of the electrode. This local geometric optimization ensures uniform discharge and maximizes efficiency in the critical discharge region

Inventive Principle:
Principle #3Local quality

2Strength

If a conventional thick inner electrode is used in the excimer lamp, then the structural strength is improved, but the lifespan is short due to arcing

Engineering Contradiction:
Improvestructural strengthVSAvoidlifespan
Core Design Contradiction:
StrengthVSDuration of action of stationary object

Solution Approach 1:

The patent applies parameter changes by reducing the outer diameter of the inner electrode to less than 0.5 mm (specifically 0.02-0.4 mm). This parameter change prevents arcing by ensuring uniform electric field distribution and avoiding field concentration that would occur with thicker electrodes. The optimized parameter maintains structural strength while eliminating the arcing problem that limits lifespan

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by optimizing the local geometry of the electrode-dielectric interface. The specific geometric ratio (R/ro)/ln(R/ro) > 8 ensures that the electric field is uniformly distributed at the critical interface region, preventing field concentration and arcing. This local geometric optimization protects the electrode from arcing damage and extends lamp lifespan

Inventive Principle:
Principle #3Local quality

3Productivity

If the inner electrode outer diameter is reduced to less than 0.5 mm, then the wall plug efficiency is greatly improved, but the manufacturing precision requirement increases

Engineering Contradiction:
Improvewall plug efficiencyVSAvoidmanufacturing precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by specifying a precise geometric ratio (R/ro)/ln(R/ro) > 8 in addition to the outer diameter constraint. This ratio parameter provides a manufacturing tolerance buffer - as long as the electrode outer diameter ro and dielectric inner radius R maintain this ratio relationship, the efficiency benefit is achieved even with normal manufacturing variations. This transforms the precision requirement from an absolute dimension constraint to a relative ratio constraint, which is easier to control in manufacturing

Inventive Principle:
Principle #35Parameter changes

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 design significantly enhances efficiency and extends the lifespan of the excimer lamp, allowing for high-energy UV-C radiation generation with improved uniformity and reduced nitrogen oxide production, enabling efficient ozone generation and UV-C radiation production without warm-up time.

Implementation Method 1

The excimer emission is generated by means of silent electrical discharge in a discharge chamber filled with an excimer-forming gas. Due to the electric field generated between the electrodes a discharge occurs, generating excimer molecules.

Methodology Applied
Scientific EffectElectrical discharge: Electric Arc

Implementation Method 2

When these excited molecules return to ground state, high-energy ultraviolet light is emitted.

Methodology Applied
Scientific EffectExcimer emission: Luminescence

Data Source

PatentEP3648143B1Vacuum ultraviolet excimer lamp with a thin wire inner electrode
Publication Date: 2021.05.19 XYLEM EURO GMBH
  • EP3648143B1 patent drawingFigure 1~2
  • EP3648143B1 patent drawingFigure 3~4
  • EP3648143B1 patent drawingFigure 5~6

AI summary

The invention relates to a VUV excimer lamp (1) comprising a dielectric tube (3) for holding an excimer-forming gas (5), a first electrode (2) disposed within said tube (3), a second electrode (4) arranged outside of said tube (3), wherein said first electrode (2) is elongated and includes a thin wire with an outer diameter of less than 0.5 mm.