Handheld Laser Plasma Sensing for Reflection Shutoff

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Solution Overview

Problem

Handheld laser devices with high power levels pose safety hazards due to invisible laser energy reflection, and conventional cooling systems hinder maneuverability in small workspaces.

Innovation Solution

A handheld laser device equipped with a plasma sensor to detect plasma emission during processing, a controller to compare optical intensity values with a threshold, and an air-cooling system to reduce size and enhance safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high power laser (at least 1 kW) is used for industrial cutting and welding, then productivity and manufacturing capability are improved, but safety hazards increase due to invisible laser energy reflection

Engineering Contradiction:
Improveindustrial cutting and welding capabilityVSAvoidsafety hazards from invisible laser reflection
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system uses a plasma sensor to detect plasma emission during laser processing and provides feedback to the controller. When plasma is detected (indicating proper absorption), the system continues operating. When no plasma is detected (indicating possible reflection), the controller shuts off the laser to prevent safety hazards. This feedback mechanism enables high power operation while mitigating reflection risks.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system converts the harmful effect of invisible laser reflection into a detectable signal by using a plasma sensor. Plasma emission serves as a beneficial indicator that laser energy is being properly absorbed. The absence of plasma signals potential reflection, allowing the system to proactively prevent hazards while maintaining high productivity.

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

2Reliability

If large water-based or liquid refrigerant-based chillers are used to cool the laser, then laser operation reliability is improved, but device portability and ease of operation deteriorate due to large size

Engineering Contradiction:
Improvelaser operation reliabilityVSAvoidmaneuverability in small workspaces
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention extracts the cooling function from the traditional large water-based chiller system and implements it as a compact integrated cooling system within the handheld device. This extraction enables reliable laser operation while achieving the portability needed for small workspaces and irregular geometries.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The cooling system is nested within the handheld laser device structure, with the laser source, cooling mechanism, and control systems integrated into a single portable unit. This nesting approach maintains reliable cooling performance while achieving compact dimensions suitable for manual handling and use in confined spaces.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Stability of the object's composition

If conventional large cooling systems are used, then laser power stability is improved, but device complexity and size increase

Engineering Contradiction:
Improvelaser power stabilityVSAvoidcooling system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The invention merges the cooling system with the handheld laser device, integrating the laser source, cooling mechanism, plasma sensor, and controller into a unified compact system. This combination maintains laser power stability through effective cooling while reducing overall device complexity compared to separate conventional systems.

Inventive Principle:
Principle #5Merging (Combining)

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

Prevents prolonged exposure to laser light by automatically shutting off the laser when reflection occurs, and allows for compact, portable operation in confined spaces.

Implementation Method 1

a plasma sensor configured to detect plasma emitted from the workpiece material during a material processing operation

Methodology Applied
Scientific EffectPlasma emission: Plasma

Implementation Method 2

compare an optical intensity value obtained by the plasma sensor to a threshold value

Methodology Applied
Scientific EffectOptical intensity detection: Photoelectric Effect

Data Source

PatentEP4204177B1Handheld laser system and method
Publication Date: 2026.02.11 IPG PHOTONICS CORP
  • EP4204177B1 patent drawingFigure 1
  • EP4204177B1 patent drawingFigure 2
  • EP4204177B1 patent drawingFigure 3A~3B

AI summary

A handheld laser system. In certain examples the handheld laser system includes a laser source emitting laser light at a wavelength for performing a material processing operation on a workpiece material with a laser beam of the emitted laser light, a plasma sensor configured to detect plasma emitted from tire workpiece material daring a material processing operation, and a controller coupled to the plasma sensor and configured to: compare an optical intensity value obtained by the plasma sensor to a threshold value at a time when a predetermined time period has elapsed after the material processing operation has commenced, and produce a control command based on the comparison.