Polygon Mirror Laser Grooving With Non-Condensing Beam Control

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Solution Overview

Problem

Existing groove processing devices using laser beams with polygon mirrors face issues of non-uniform groove formation and contamination of optical components due to laser beam division at corner portions, leading to shallow end portions and incorrect irradiation.

Innovation Solution

Incorporating a lens with a non-condensing portion that allows divided laser beams from corner portions to pass through without focusing, preventing groove formation and minimizing irradiation of surrounding devices, thus maintaining uniformity and depth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a shielding plate is provided to block divided laser beams from corner portions, then groove uniformity is improved, but optical components are contaminated due to processing of the shielding plate

Engineering Contradiction:
Improvegroove uniformityVSAvoidoptical component contamination
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a beam splitter as an intermediary component that redirects divided laser beams away from the optical system. The beam splitter is positioned to receive divided beams from polygon mirror corner portions and reflect them toward a beam stop, preventing contamination of condensing lenses and other optical components while maintaining groove processing uniformity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the harmful divided laser beams from the main optical path by using a beam splitter to separate them from the primary laser beam path. This allows the main beam to continue processing grooves while the divided beams are diverted to a safe location, eliminating the contamination problem.

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If the laser beam is incident on the corner portion of the polygon mirror, then the optical path is simplified, but the groove depth becomes non-uniform due to insufficient energy density

Engineering Contradiction:
Improveoptical path complexityVSAvoidgroove depth uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent converts the harmful effect of divided laser beams (insufficient energy density causing shallow grooves) into a beneficial configuration by redirecting these beams away from the workpiece. The beam splitter and beam stop arrangement ensures that divided beams from corner portions do not reach the steel sheet, preventing non-uniform groove depth while maintaining the simplified optical path structure.

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

3Device complexity

If the divided laser beams are irradiated in a different direction, then the optical system is simpler, but incorrect positions or surrounding devices are erroneously processed

Engineering Contradiction:
Improveoptical system complexityVSAvoiderroneous processing
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The beam splitter serves as an intermediary that intercepts divided laser beams before they can be irradiated in incorrect directions. By positioning the beam splitter in the optical path of divided beams, the system redirects these beams toward a beam stop, preventing erroneous processing of incorrect positions or surrounding devices while maintaining the simplicity of the optical system.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary anti-action by placing the beam splitter and beam stop in advance in the potential path of divided laser beams. This preemptive arrangement prevents erroneous processing before it can occur, blocking divided beams from reaching incorrect positions or surrounding devices that might be damaged by misplaced irradiation.

Inventive Principle:
Principle #9Preliminary anti-action

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

Achieves uniform groove processing and depth without contaminating optical components, ensuring accurate and efficient groove formation on steel sheets while avoiding damage to surrounding equipment.

Implementation Method 1

the laser beam LB reflected from the polygon mirror 10 is focused on one spot on the surface of the steel sheet 20 through a condensing lens 12

Methodology Applied
Scientific EffectLaser beam focusing: Focusing

Implementation Method 2

irradiate a surface of a steel sheet with a laser beam LB

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 3

the divided laser beams LB 1 and LB2 pass through a non-condensing portion 13B of the lens 13

Methodology Applied
Scientific EffectLight transmission without focusing: Light

Data Source

PatentEP3970904B1Groove processing device and groove processing method
Publication Date: 2023.06.21 NIPPON STEEL CORPORATION
  • EP3970904B1 patent drawingFigure 1A~1B
  • EP3970904B1 patent drawingFigure 2
  • EP3970904B1 patent drawingFigure 3~4

AI summary

A groove processing device (100) that forms a groove in a surface of an object using a laser beam includes: a light source device (11) that outputs the laser beam; a polygon mirror (10) that reflects the laser beam output from the light source device (11); and an optical system that is provided on an optical path of the laser beam reflected from the polygon mirror (10) and includes a condensing portion (13A) which transmits the laser beam reflected from one surface of the polygon mirror (10) so as to be focused on the surface of the object and a non-condensing portion (13B) which is provided outside the condensing portion (13A) and transmits the laser beam reflected from a corner portion, in which two adjacent surfaces of the polygon mirror (10) meet, so as not to be focused on the surface of the object.