Mechanically Sealed Plasma Lamp Tube Without Brazed Sapphire Windows

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Solution Overview

Problem

Traditional high-intensity arc lamps face issues with gas turbulence and compatibility with certain ionizable media due to brazing methods, which limit operating temperature and plasma stability, and the production of sapphire windows welded to tubes is complex and expensive.

Innovation Solution

A mechanically sealed pressurized chamber assembly for a laser sustained plasma lamp using sapphire windows and metal seal rings that are not welded or brazed, with a clamping structure to maintain the seal and accommodate ionizable media like Xenon and Krypton, allowing for higher operating temperatures and improved plasma stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If traditional brazing methods are used to seal sapphire windows to the chamber tube, then the seal integrity is maintained, but the operating temperature is limited and gas turbulence increases

Engineering Contradiction:

Improveoperating temperatureVSAvoidplasma stability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The sealing system is divided into separate components: a metal seal ring that contacts the chamber tube and a separate clamping structure, rather than directly brazing the sapphire window to the tube. This segmentation allows each component to be optimized for its specific function without the constraints of direct brazing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A metal seal ring is introduced as an intermediary component between the sapphire window and the chamber tube. This intermediary allows mechanical sealing without direct brazing of sapphire to metal, enabling higher operating temperatures while maintaining seal integrity through the metal-to-metal contact of the seal ring.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If sapphire windows are welded or brazed to the chamber tube, then the seal is hermetic, but the manufacturing complexity and cost increase

Engineering Contradiction:

Improveseal integrityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The traditional thermal joining method (welding or brazing) is replaced with a mechanical sealing system consisting of a metal seal ring and clamping structure. This mechanical approach achieves hermetic sealing without the complexity of precision brazing operations and allows for easier assembly and disassembly.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Illumination intensity

If the chamber is pressurized with ionizable media, then the plasma radiance is enhanced, but gas turbulence increases without proper sealing

Engineering Contradiction:

Improveplasma radianceVSAvoidgas turbulence

Core Design Contradiction:

Illumination intensityVSStability of the object's composition

Solution Approach 1:

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sealing approach changes from thermal joining (brazing) to mechanical joining (clamping with seal ring). This parameter change in the sealing method enables the system to withstand higher pressures and temperatures without compromising seal integrity, thereby supporting enhanced plasma radiance while controlling gas turbulence.

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 solution provides a stable and efficient high-intensity light source with reduced gas turbulence and compatibility with various ionizable media, enhancing radiance and operational longevity by avoiding the limitations of traditional brazing methods and enabling easier integration of metal halides for enhanced operational pressure.

Implementation Method 1

The chamber assembly is bounded by a chamber tube, an ingress sapphire window, a first metal seal ring configured to seal against the chamber tube ingress end and the ingress sapphire window, an egress sapphire window, and a second metal seal ring configured to seal against the chamber tube egress end and the egress sapphire window

Methodology Applied

Scientific EffectMechanical sealing: Mechanical Fastener

Implementation Method 2

A mechanical clamping structure external to the chamber assembly is configured to clamp across at least a portion of the ingress sapphire window and the egress sapphire window

Methodology Applied

Scientific EffectMechanical clamping: Mechanical Fastener

Implementation Method 3

A mechanically sealed pressurized chamber assembly for a laser sustained plasma lamp using sapphire windows

Methodology Applied

Scientific EffectOptical transmission: Lens

Implementation Method 4

laser sustained plasma lamp

Methodology Applied

Scientific EffectLaser sustained plasma: Laser

Implementation Method 5

An electrical discharge is generated between the anode and cathode to provide power to the excited (e.g. ionized) gas to sustain the light emitted by the ionized gas during operation of the light source

Methodology Applied

Scientific EffectPlasma generation: Plasma

Implementation Method 6

The cathode struts 3c hold the cathode 3b rigidly in place and conduct current to the cathode 3b

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 7

An electrical discharge is generated between the anode and cathode to provide power to the excited (e.g. ionized) gas

Methodology Applied

Scientific EffectElectrical discharge: Electric Arc

Implementation Method 8

The thermal conductivity of sapphire transports heat to the flange 3c of the lamp and distributes the heat evenly to avoid cracking the window 3d

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 9

The electrons are emitted thermionically from the cathode 3b, so the cathode tip must maintain a high temperature and low-electron-emission to function

Methodology Applied

Scientific EffectThermionic emission: Thermionic Emission

Implementation Method 10

The getters 3e are wrapped around the cathode 3b and placed on the struts. The getters 3e absorb contaminant gases that evolve in the lamp during operation

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentEP3540760B1Mechanically sealed tube for laser sustained plasma lamp and production method for same

Publication Date: 2023.11.29 EXCELITAS TECHNOLOGIES CORP

Figure 1~2
Figure 3A~3B
Figure 4A~4C

AI summary

A laser sustained plasma lamp includes a mechanically sealed pressurized chamber assembly (330) configured to contain an ionizable material. The chamber assembly is bounded by a chamber tube (310), an ingress sapphire window (340), a first metal seal ring (320) configured to seal against the chamber tube ingress end and the ingress sapphire window, an egress sapphire window (342), and a second metal seal ring (322) configured to seal against the chamber tube egress end and the egress sapphire window. A mechanical clamping structure (350, 355) external to the chamber assembly is configured to clamp across at least a portion of the ingress sapphire window and the egress sapphire window. The ingress sapphire window and the egress sapphire window are not connected to the chamber tube via welding and/or brazing.