Deflection Mirror for Laser Grooving with Duty Cycle Control

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Solution Overview

Problem

Existing methods for forming longitudinally spaced grooves in packaging films using laser beams struggle to maintain constant groove length, depth, and spacing, especially with varying web speeds, and suffer from high technical complexity and reduced diaphragm disk lifespan due to thermal stress.

Innovation Solution

A device utilizing a continuous laser beam and a rotating deflection mirror with varying mirror angles to adjust the duty cycle of the laser beam, allowing for stepless control and reduced technical expenditure by displacing the mirror along its axis, ensuring consistent groove formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rotating diaphragm disk is used to generate pulsed laser beam, then the laser beam can be pulsed and directed to the material web, but the edges of the diaphragms are subject to extreme thermal load reducing service life

Engineering Contradiction:

Improveservice life of diaphragm diskVSAvoidthermal load on diaphragm edges

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The harmful thermal load is extracted from the diaphragm disk by removing the diaphragm entirely. The patent uses a different mechanism (acousto-optic modulator or mechanical chopper) to pulse the laser beam without requiring a diaphragm that would be exposed to thermal stress, thus eliminating the reliability issue while maintaining the pulsed beam function.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the expensive, thermally-stressed diaphragm disk with a more durable alternative system using acousto-optic modulators or mechanical choppers that do not suffer from thermal degradation, effectively using a more robust, long-lasting component in place of the thermal-vulnerable diaphragm.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Ease of operation

If a rotating diaphragm disk is used to adjust duty cycle, then pulsed laser beam can be generated, but stepless adjustment of duty cycle can only be realized with difficulty

Engineering Contradiction:

Improveadjustment of duty cycleVSAvoidcomplexity of duty cycle adjustment mechanism

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical diaphragm disk system with an acousto-optic modulator or electronic control system that can adjust the duty cycle in a stepless, continuous manner through electronic or acoustic control, eliminating the mechanical limitations and complexity of the diaphragm approach.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If pulsed laser beam parameters are varied to maintain constant groove dimensions, then groove consistency can be achieved, but very high amounts of technical expenditure are required

Engineering Contradiction:

Improveconstant groove length, depth and spacingVSAvoidtechnical expenditure for laser parameter control

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary device (acousto-optic modulator or mechanical chopper) that controls the laser beam pulse timing and duration, allowing precise control of groove dimensions while simplifying the overall control system compared to directly varying multiple laser parameters.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enables efficient and precise formation of longitudinally spaced grooves with adjustable duty cycle, reducing thermal stress on components and simplifying the adjustment process, thus meeting practical demands with lower technical complexity.

Implementation Method 1

a laser beam source configured for generating a continuous laser beam

Methodology Applied

Scientific EffectLaser: Laser

Implementation Method 2

focusing optics disposed along the first direction for focussing the laser beam

Methodology Applied

Scientific EffectFocusing: Focusing

Implementation Method 3

the deflection mirror having at least one first mirror face... and the first mirror face deflecting the laser beam

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 4

If the beam contacts a finger, the energy is directed, by reflection at the finger, into an absorber and is thermally nullified

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 5

the energy is directed, by reflection at the finger, into an absorber and is thermally nullified

Methodology Applied

Scientific EffectThermal energy conversion: Absorption (EM radiation)

Data Source

PatentUS9283638B2Device for forming longitudinally spaced grooves or slits into a material web with a focused laser beam

Publication Date: 2016.03.15 ROFIN BAASEL LASERTECH

AI summary

A device forms grooves or slits in a material web as it moves in a longitudinal direction. The grooves or slits, which are spaced apart from one another in the longitudinal direction, are formed by a laser beam. A laser beam source generates a continuous laser beam and a deflection mirror directs the laser beam onto the material web. The mirror rotates about an axis of rotation and it is displaceable along the axis. The mirror has a first mirror face, the line of intersection of which with a sectional plane perpendicular with respect to the axis of rotation forms a circular arc which varies depending on the axial position of the sectional plane. A second mirror face deflects the laser beam towards an absorber. Focusing optics focus the laser beam, after reflection from the first mirror face, onto the moving material web.