Flash Discharge Lamp Trigger Electrode Stress Isolation

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Solution Overview

Problem

Conventional flash discharge lamps experience unstable operation due to repeated expansion and contraction of the trigger electrode, leading to metal foil tearing and reduced lamp emission, caused by differential expansion coefficients and shock waves, resulting in unreliable energy delivery for high-energy applications like semiconductor substrate treatment.

Innovation Solution

A recessed part is formed on the trigger electrode's surface, allowing the silica glass tubular body to penetrate and absorb expansion stress, with a high-melting-point coating to prevent oxidation and adhesion, and positioned behind the electrode tip to minimize light exposure, ensuring reliable emission by isolating the metal foil from stress and vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the trigger electrode is hermetically sealed within the sealed tubular body, then oxidation of the trigger electrode is prevented, but the metal foil becomes brittle and tears due to repeated expansion and contraction stress

Engineering Contradiction:
Improveprevention of trigger electrode oxidationVSAvoidmetal foil strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The sealed tubular body is divided into two separate sealed sections: one sealing the trigger electrode and another sealing the metal foil. This segmentation isolates the metal foil from the thermal expansion and contraction stresses affecting the trigger electrode, preventing foil tearing while maintaining oxidation protection for both components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A buffer structure is introduced between the trigger electrode and metal foil sealing regions. This intermediary buffer zone absorbs and isolates the mechanical stresses from thermal expansion and contraction, preventing stress transmission to the metal foil while maintaining the hermetic seal integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the trigger electrode is sealed within the sealed tubular body, then sputtering of the trigger electrode is prevented, but the hermetically sealed arrangement becomes complex

Engineering Contradiction:
Improveprevention of trigger electrode sputteringVSAvoidhermetically sealed arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealing structures for the trigger electrode and metal foil are merged into a single integrated sealed tubular body with two sealed sections. This combining approach maintains the protective function against sputtering while simplifying the overall structure compared to using separate sealed containers for each component.

Inventive Principle:
Principle #5Merging (Combining)

3Stress or pressure

If the trigger electrode is allowed to expand freely, then thermal expansion stress is reduced, but the gap between the electrode and tubular body allows oxidation

Engineering Contradiction:
Improvethermal expansion stressVSAvoidoxidation protection
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The sealed tubular body is segmented into distinct sealed zones that maintain hermetic isolation while accommodating thermal expansion. Each segment is independently sealed, allowing the trigger electrode to expand within its designated space without compromising the oxidation protection provided by the sealed environment.

Inventive Principle:
Principle #1Segmentation

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 solution prevents metal foil tearing and maintains reliable lamp operation by absorbing expansion stress and reducing the impact of shock waves, ensuring consistent energy delivery and preventing crack formation in the tubular body.

Implementation Method 1

as a result of the different coefficients of expansion between the silica glass comprising the sealed tubular body 4 and the tungsten comprising the trigger electrode 3

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

a coating layer of metal with a high melting point is formed on the surface of the above described recessed part

Methodology Applied
Scientific EffectOxidation resistance: Oxidation

Implementation Method 3

a flash discharge lamp which is used, for example, for heat treatment of semiconductor substrates and liquid crystal substrates

Methodology Applied
Scientific EffectElectrical discharge: Electric Arc

Implementation Method 4

when light is emitted from the lamp in the space in the vicinity of the lamp, shock waves are formed. The effect of these shock waves causes the lamp to vibrate

Methodology Applied
Scientific EffectShock wave: Shock Wave

Data Source

PatentEP1883097B1Flash discharge lamp
Publication Date: 2010.07.21 USHIO INC
  • EP1883097B1 patent drawingFigure 1
  • EP1883097B1 patent drawingFigure 2
  • EP1883097B1 patent drawingFigure 3(a)~4

AI summary

Flash discharge lamp having an arc tube in which there is a pair of opposed electrodes, a rod-shaped trigger electrode which runs along the outside surface of the arc tube in its lengthwise direction; and a sealed tubular body which jackets the trigger electrode and has a hermetically sealed arrangement containing a metal foil. The trigger electrode has a recessed part on its surface in the vicinity of the metal foil and the recessed part is at least partially filled with the material of which the sealed tubular body is formed.