Rotating Gas Containment for Laser Plasma Light Source

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional laser sustained plasma (LSP) broadband light sources suffer from uneven thermal distribution and convection-induced noise, leading to reduced plasma light output, especially at higher pumping powers.

Innovation Solution

A broadband plasma light source equipped with a rotatable gas containment structure and a rotational drive system that rotates the structure at sufficient speed to suppress convective plumes, achieving uniform heating and improved light output by eliminating thermal and refractive instabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If higher pumping powers are used to increase light output, then the brightness and power of the plasma light source is improved, but thermal distribution becomes more uneven and convection-induced noise increases

Engineering Contradiction:

Improvelight output powerVSAvoidthermal distribution uniformity

Core Design Contradiction:

PowerVSTemperature

Solution Approach 1:

The gas containment structure is rotated at controlled speeds to dynamically redistribute thermal energy throughout the plasma volume. This dynamic motion transforms the static thermal distribution problem into a controllable dynamic process, allowing uniform heating while maintaining high pumping powers.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters by introducing rotational motion with specific speed ranges (50-2000 RPM). This parameter change fundamentally alters the thermal and fluid dynamics within the plasma, converting uneven static heating into uniform dynamic heating while suppressing convection-induced noise.

Inventive Principle:

Principle #35Parameter changes

2Power

If higher pumping powers are used to increase light output, then the brightness and power of the plasma light source is improved, but convection-induced noise increases

Engineering Contradiction:

Improvelight output powerVSAvoidillumination stability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

Rotation of the gas containment structure creates dynamic conditions that suppress convection currents. The rotational motion stabilizes the plasma by preventing the formation of convective plumes that cause illumination noise, thereby improving reliability while maintaining high power operation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention converts the harmful effect of high-power pumping (which generates convection and noise) into a beneficial outcome. By rotating the containment structure, the system uses the energy and motion to suppress convection, transforming what would be a destabilizing factor into a stabilizing mechanism that reduces noise and improves illumination stability.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Temperature

If the gas containment structure is rotated to achieve uniform heating, then thermal distribution uniformity is improved, but device complexity increases

Engineering Contradiction:

Improvethermal distribution uniformityVSAvoidrotational mechanism complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The gas containment structure serves multiple functions: it contains the plasma, provides the optical window for laser entry and light collection, and acts as the rotating element for thermal distribution. This multi-functionality reduces overall device complexity by eliminating the need for separate heating mechanisms or additional rotating components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its own operational energy to drive the rotation and achieve uniform heating. The pump laser energy and plasma generation process are coupled with the rotational motion, allowing the system to self-regulate thermal distribution without requiring external heating elements or complex thermal management systems.

Inventive Principle:

Principle #25Self-service

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 results in rotationally uniform heating distribution, reduced damage to the glass walls, improved focus stability of the pump illumination, and enhanced performance of the LSP light source with reduced noise and simplified cooling configurations.

Implementation Method 1

LSP lamps suffer from uneven thermal distribution on the glass of the lamp and from convection-induced noise in the laser pump illumination

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 2

a reflector element configured to direct a portion of the pump illumination into the gas to sustain a plasma

Methodology Applied

Scientific EffectPlasma: Plasma

Implementation Method 3

a pump source configured to generate pump illumination

Methodology Applied

Scientific EffectLaser: Laser

Data Source

PatentUS11596048B2Rotating lamp for laser-sustained plasma illumination source

Publication Date: 2023.02.28 KLA CORP

AI summary

A broadband light source is disclosed. The broadband light source includes a rotatable gas containment structure. The broadband light source includes a rotational drive system configured to rotate the rotatable gas containment structure about the horizontal axis of rotation of the rotatable gas containment structure. The broadband light source includes a pump source configured to generate pump illumination and a reflector element configured to direct a portion of the pump illumination into the gas to sustain a plasma. The reflector is configured to collect a portion of broadband light emitted from the plasma.