Sub-cooled Liquid Jet Cooling for Laser Excitation Sections

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Solution Overview

Problem

The existing laser oscillation cooling devices, such as those using liquid nitrogen, face insufficient cooling ability when attempting to achieve high laser output, leading to increased medium temperature and degraded laser oscillation efficiency due to film boiling and inadequate cooling capacity.

Innovation Solution

A laser oscillation cooling device that utilizes extremely low temperature liquids, such as liquid nitrogen or liquid helium, which are brought into a sub-cool state through pressurization and jetted to the laser excitation section, with a pressure regulating section to adjust the sub-cool degree and a flow rate regulating section to optimize heat removal, and a control section that adjusts the flow rate based on measured output or temperature to maintain efficient cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If liquid nitrogen is supplied to cool the laser excitation device, then cooling is provided, but the cooling ability becomes insufficient at high laser output due to film boiling

Engineering Contradiction:
Improvecooling abilityVSAvoidcooling effectiveness
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent changes the temperature parameter of the cooling liquid by introducing a sub-cooling mechanism. The liquid nitrogen is cooled below its normal boiling point temperature to create a sub-cooled state, which prevents film boiling and maintains effective heat transfer at high laser outputs. This parameter change directly resolves the contradiction by enabling sufficient cooling capacity while maintaining reliability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the temperature of the medium is reduced to improve laser oscillation limit, then laser oscillation efficiency is improved, but cooling complexity increases

Engineering Contradiction:
Improvelaser oscillation limitVSAvoidcooling system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a self-regulating cooling system where the control section automatically adjusts the flow rate of sub-cooled liquid based on temperature or output measurements. This self-service mechanism maintains optimal cooling without requiring complex manual intervention, thereby improving laser oscillation limit while minimizing the increase in cooling system complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent incorporates feedback control by measuring temperature or output and using this information to regulate the cooling liquid flow rate. This feedback mechanism ensures the laser oscillation limit is maintained while avoiding excessive cooling system complexity through automated adjustment.

Inventive Principle:
Principle #23Feedback

3Productivity

If high laser output is attempted, then productivity is improved, but cooling ability becomes insufficient leading to degraded oscillation efficiency

Engineering Contradiction:
Improvelaser outputVSAvoidlaser oscillation efficiency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the temperature parameter of the cooling liquid to a sub-cooled state, which fundamentally alters the heat transfer characteristics. This enables the system to handle high laser outputs (improved productivity) without experiencing film boiling, thereby maintaining laser oscillation efficiency (reliability) even at elevated power levels.

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

This configuration provides a sufficient cooling effect, preventing film boiling and maintaining efficient laser oscillation by autonomously regulating the cooling capacity, thereby improving the laser oscillation limit and allowing for the reuse of the cooling medium.

Implementation Method 1

a pressurizing section that pressurizes the extremely low temperature liquid

Methodology Applied
Scientific EffectPressurization: Pressurisation

Implementation Method 2

The extremely low temperature liquid of the sub-cool state is jetted to the laser excitation section, whereby it is possible to efficiently remove heat from the laser excitation section

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 3

a jetting supply section that jets the extremely low temperature liquid in the sub-cool state to the laser excitation section

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3196990B1Laser oscillation cooling device
Publication Date: 2021.04.21 MITSUBISHI HEAVY IND LTD
  • EP3196990B1 patent drawingFigure 1~2
  • EP3196990B1 patent drawingFigure 3
  • EP3196990B1 patent drawingFigure 4~5

AI summary

A laser oscillation cooling device (100) is provided with; a light emitting section (1) that emits laser excitation light (Z1); a laser excitation section (2), which emits laser light (Z2) by exciting the laser excitation light (Z1), and which locally generates heat; a storage tank (3) capable of storing an extremely low temperature liquid (L); a pressurizing section (31) that brings the extremely low temperature liquid (L) intro a sub-cool state by pressurizing the inside of the storage tank (3); and a jetting supply section (4) that removes heat from the laser excitation section (2) by jetting the extremely low temperature liquid (L) in the sub-cool state to the laser excitation section.