UV Pulsed Laser Source With Frequency Conversion Module

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Solution Overview

Problem

Current laser material processing systems face challenges in generating a focused beam of UV pulsed laser radiation that is resistant to optical damage, particularly when processing materials with composite structures, as existing systems are vulnerable to degradation by UV radiation, and there is a need for precise control over pulse energy to selectively ablate thin films without damaging underlying materials.

Innovation Solution

A UV pulsed laser radiation generating apparatus comprising a laser source, fiber-coupling module, optical fiber, frequency-conversion module, beam-scanning module, focusing lens, and pulse-compression module, which converts IR pulsed laser radiation to UV radiation using non-linear harmonic generation and includes a Kagome photonic crystal fiber for spectral broadening and pulse compression, ensuring high energy and precision in material processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If UV laser radiation is used for material processing, then manufacturing precision and processing quality are improved, but optical components are vulnerable to degradation and damage

Engineering Contradiction:
Improveprocessing qualityVSAvoidoptical component durability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent uses an infrared laser as an intermediary to perform the material processing, avoiding direct use of UV radiation on optical components. The infrared laser operates at a wavelength that does not degrade the optical components, yet still achieves the desired processing results through its interaction with the material being processed.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the traditional UV laser optical system with a different physical approach using infrared laser radiation. This substitution eliminates the need for UV-resistant optical components while maintaining processing capability through the unique interaction properties of infrared radiation with materials.

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

2Productivity

If higher pulse energy is used to ablate materials faster, then productivity is improved, but selective ablation of thin films becomes difficult

Engineering Contradiction:
Improveprocessing speedVSAvoidselective ablation capability
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent utilizes the unique parameter of infrared laser wavelength to achieve selective ablation. By operating at infrared wavelengths, the laser interacts differently with various materials based on their absorption characteristics, enabling selective removal of thin films at controlled energy levels while maintaining high processing speeds through optimized pulse parameters.

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 apparatus effectively generates a focused beam of UV pulses with controlled pulse duration and energy, capable of ablating a broad range of materials with minimal collateral damage, enabling precise processing of composite structures while resisting optical degradation, thus enhancing processing speed and quality.

Implementation Method 1

IR laser-radiation is converted into visible and ultraviolet (UV) laser-radiation by harmonic generation in non-linear optical crystals

Methodology Applied
Scientific EffectNon-linear harmonic generation: Second Harmonic Generation

Implementation Method 2

Kagome photonic crystal fiber for spectral broadening and pulse compression

Methodology Applied
Scientific EffectSpectral broadening: Photonic Crystal

Implementation Method 3

Focused pulsed laser-radiation above a threshold intensity removes material from a workpiece by ablation

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 4

Focused beam of UV pulsed laser-radiation can selectively remove a thin-film without damaging underlying material

Methodology Applied
Scientific EffectAblation: Ablation

Data Source

PatentEP3504589B1Modular ultraviolet pulsed laser-source
Publication Date: 2021.09.22 COHERENT KAISERSLAUTERN
  • EP3504589B1 patent drawingFigure 1
  • EP3504589B1 patent drawingFigure 2

AI summary

Apparatus (10) for generating ultraviolet (UV) pulsed laser-radiation for material-processing includes a laser-source (20) providing infrared (IR) pulsed laser-radiation and a frequency-conversion module (28). A lithium tetraborate (Li2B4O7) crystal (72) located within the frequency-conversion module (28) converts the IR pulsed laser-radiation to UV pulsed laser-radiation by non-linear harmonic generation. The frequency-conversion module (28) is an airtight enclosure that may be evacuated or contain a dry gas. A flexible optical fiber-assembly (24) transports the IR pulsed laser-radiation from the laser-source to the frequency-conversion module.