Laser-to-Fiber Optical Axis Alignment Using Intensity Distribution

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Solution Overview

Problem

Current optical axis alignment methods in laser processing devices do not ensure both high precision and appropriate laser beam shape, often requiring repeated adjustments and reducing work efficiency due to the mismatch between maximum power and optimal beam shape positions.

Innovation Solution

The method aligns the optical axis between the laser oscillator and optical fiber based on the light intensity distribution, minimizing the numerical aperture to achieve precise alignment and a desired laser beam shape, using a laser light evaluator with a mirror unit, integrating sphere, and CCD camera to process the intensity distribution for accurate positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the condenser lens is positioned to maximize laser beam power, then the coupling efficiency between laser oscillator and optical fiber is improved, but the laser beam shape becomes inappropriate for high-precision processing

Engineering Contradiction:
Improvecoupling efficiencyVSAvoidlaser beam shape
Core Design Contradiction:
Loss of energyVSShape

Solution Approach 1:

The patent transitions from one-dimensional power maximization to two-dimensional optimization by simultaneously considering both power coupling efficiency and beam shape quality. The evaluation function combines multiple parameters (power, beam width, symmetry) to achieve comprehensive optimization in multiple dimensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the optimization parameter from单一的power maximization to a composite evaluation function that includes power, beam width, and symmetry parameters. This allows the system to find optimal condenser lens positions that satisfy multiple performance requirements simultaneously.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the optical axis alignment is performed based on maximum power output, then the coupling efficiency is improved, but repeated adjustments are required which decreases work efficiency

Engineering Contradiction:
Improvecoupling efficiencyVSAvoidwork efficiency
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The patent performs preliminary comprehensive evaluation of beam quality parameters during the alignment process. By evaluating beam shape characteristics alongside power output, the system identifies the optimal position in advance, preventing the need for repeated adjustments and improving workflow efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism that continuously monitors both power output and beam shape parameters. The evaluation function provides real-time feedback on alignment quality, guiding the adjustment process toward the optimal position and reducing iterative adjustments.

Inventive Principle:
Principle #23Feedback

3Device complexity

If the condenser lens position is fixed for maximum power output, then the alignment process is simplified, but the final output laser light does not have the desired shape for high-precision processing

Engineering Contradiction:
Improvealignment process complexityVSAvoidlaser beam shape
Core Design Contradiction:
Device complexityVSShape

Solution Approach 1:

The patent creates a universal evaluation function that simultaneously assesses multiple performance criteria (power, beam width, symmetry). This multi-functional evaluation approach allows a single alignment position to satisfy multiple requirements, eliminating the need for separate optimization steps.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 approach enhances the accuracy of optical axis alignment, ensuring the final output laser light has an appropriate shape and improved precision, reducing the need for repeated adjustments and increasing work efficiency.

Implementation Method 1

a light-receiving unit having a light-receiving surface that receives the laser light

Methodology Applied
Scientific EffectLight detection: Photoelectric Effect

Implementation Method 2

a mirror unit configured to deflect, toward the light-receiving unit, part of the laser light radiated from the optical fiber

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 3

a neutral-density filter configured to attenuate the laser light that has passed through the field lens

Methodology Applied
Scientific EffectLight attenuation: Absorption (EM radiation)

Implementation Method 4

a field lens disposed at a position corresponding to a focal point of the fθ lens

Methodology Applied
Scientific EffectLight focusing: Lens

Data Source

PatentEP3553574B1Alignment method
Publication Date: 2023.01.04 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3553574B1 patent drawingFigure 1
  • EP3553574B1 patent drawingFigure 2~3
  • EP3553574B1 patent drawingFigure 4~5

AI summary

There is provided an optical axis alignment mechanism (20) between the laser oscillator (10) and the optical fiber (30). The laser oscillator (10) emits laser light (11), which then emerges from the emission end (32) of the optical fiber (30) via the axis alignment mechanism (20). Part of the laser light (11) is received on the light-receiving surface of the CCD camera (100) of a laser light evaluator (200). Thus, the laser light evaluator (200) acquires a light intensity distribution. The light intensity distribution is used by the optical axis alignment mechanism (20) to align the axis of the laser oscillator (10) with the axis of the optical fiber (30).