Handheld Laser Plasma Sensing for Reflected Radiation Safety

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Solution Overview

Problem

Handheld laser devices with high power levels pose safety hazards due to invisible laser radiation exposure risks, as users may mistakenly believe the device is not functioning when laser energy is reflected off the workpiece instead of being absorbed, and conventional cooling systems are bulky, making them impractical for small workspaces.

Innovation Solution

A handheld laser system 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, along with safety features like optical filters and two-stage triggers to prevent prolonged exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If high power laser radiation is used for material processing, then processing capability is improved, but safety hazards from invisible reflected radiation increase

Engineering Contradiction:
Improvelaser powerVSAvoidreflected radiation exposure
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The system uses a plasma sensor to detect plasma generation at the workpiece surface and provides feedback to the controller. When plasma is detected (indicating proper laser absorption), the system confirms safe operation. When plasma is not detected (indicating possible reflection), the controller shuts off the laser to prevent exposure hazards.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The plasma sensor acts as an intermediary between the laser system and the operator safety. It indirectly monitors laser absorption by detecting plasma emission, providing a safe way to verify proper laser-workpiece interaction without directly exposing the operator to potential reflected radiation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If conventional water-based chillers are used to cool high power lasers, then cooling effectiveness is improved, but system size and portability deteriorate

Engineering Contradiction:
Improvelaser coolingVSAvoidsystem size
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The patent replaces the conventional water-based chiller system with an air-cooling system. This substitution eliminates the need for water pumps, water reservoirs, and complex liquid cooling circuits, significantly reducing system size and weight while maintaining effective cooling of the high power laser diodes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The cooling method is changed from liquid-based to air-based cooling. This parameter change in the cooling medium allows for a more compact heat exchanger design and eliminates the auxiliary systems required for liquid cooling, making the overall laser system more portable.

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 system effectively prevents user exposure to reflected laser radiation by shutting off the laser when plasma is not detected and maintains power during normal processing, while being compact and portable for various material operations.

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

at least one optical filter configured to block light at the wavelength of the emitted laser light from reaching the plasma sensor

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Implementation Method 3

an air-cooling system coupled to the laser source for dissipating heat

Methodology Applied
Scientific EffectConvection cooling: Convection

Data Source

PatentEP4714583A2Handheld laser system and method
Publication Date: 2026.03.25 IPG PHOTONICS CORP
  • EP4714583A2 patent drawingFigure 1
  • EP4714583A2 patent drawingFigure 2
  • EP4714583A2 patent drawingFigure 3A~3B

AI summary

One aspect of the present disclosure relates to a handheld laser system, comprising a laser source configured to generate laser radiation at a wavelength for performing a material processing operation on a workpiece material with a laser beam of the generated laser radiation. The handheld laser system also comprises a housing configured as a handheld apparatus having an outlet for the laser beam, the handheld apparatus configured with one or more inlets for a shielding gas so as to be gas-cooled, the shielding gas exiting the handheld apparatus at a gas outlet to provide the shielding gas to the workpiece material. In addition, the handheld laser system comprises an air-cooling system coupled to the laser source for dissipating heat from the laser source.