Two-Dimensional Laser Beam Deflection Without Distortion

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Solution Overview

Problem

Current beam deflection systems for laser radiation suffer from significant distortions in intensity distribution when deflected at even small angles, particularly when dealing with spatially extended intensity distributions, which is problematic for microstructuring and other applications requiring precise positioning of laser spots.

Innovation Solution

The proposed arrangement employs two beam deflection elements rotating about perpendicular axes, with a specific optical design that ensures all beam components pass through the center of the entrance pupil perpendicularly, allowing for two-dimensional deflection without distortion using cylindrical relay telescopes and focusing optics to maintain a common entrance pupil and compensate for angle-dependent distortions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If beam deflection systems are used to deflect laser radiation at different angles, then the beam can be distributed across the workpiece, but significant distortions in the intensity distribution occur

Engineering Contradiction:
Improvebeam distribution efficiencyVSAvoidintensity distribution accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent introduces a second beam deflection element that deflects the beam in a direction perpendicular to the first deflection element. This two-dimensional deflection approach allows the system to compensate for distortions by controlling beam components in both lateral directions, maintaining the shape and positioning accuracy of the intensity distribution while still achieving broad beam distribution across the workpiece.

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

Solution Approach 2:

The patent uses a common entrance pupil as an intermediary optical element that all beam components pass through. This entrance pupil serves as a reference point that ensures beam components entering at different angles are properly aligned and deflected, preventing distortions in the intensity distribution while enabling efficient beam distribution across the workpiece.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the incident beam is split into different angular distributions, then extended intensity distributions are generated, but the shape of the intensity distribution changes as a function of deflection angle

Engineering Contradiction:
Improveintensity distribution flexibilityVSAvoidintensity distribution shape stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

By adding a second beam deflection element operating in a perpendicular direction, the system gains the ability to independently control beam components in both lateral directions. This two-dimensional control allows the system to maintain the shape stability of extended intensity distributions (such as arrays of laser spots) while still providing the flexibility to deflect beams across different angular distributions and cover large workpiece areas.

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

Solution Approach 2:

The patent implements a feedback mechanism where the position and angle of the two beam deflection elements are coordinated to compensate for shape changes. By monitoring the deflection angles and adjusting the second deflection element accordingly, the system maintains the stability of the intensity distribution shape while allowing flexible angular distribution for different processing patterns.

Inventive Principle:
Principle #23Feedback

3Device complexity

If a single beam deflection element is used, then the device complexity is low, but the positioning precision of laser spots deteriorates

Engineering Contradiction:
Improvedeflection system simplicityVSAvoidlaser spot positioning accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent adds a second beam deflection element that operates in a direction perpendicular to the first element. While this increases device complexity, it enables precise positioning of laser spots by controlling beam components in both lateral directions. The two-deflection-element system can accurately maintain the position and shape of spot arrays across the workpiece, which a single deflection element cannot achieve.

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

Solution Approach 2:

The common entrance pupil acts as an intermediary that coordinates the action of the two beam deflection elements. By requiring all beam components to pass through this common reference point, the system ensures that the combined effect of both deflection elements results in accurate laser spot positioning, offsetting the increased complexity with improved precision.

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

This solution enables distortion-free two-dimensional deflection of spatially extended intensity distributions, enhancing the productivity of laser processing systems by allowing larger laser spot distances and arrays, thereby increasing the efficiency of multi-beam applications and material processing.

Implementation Method 1

a first beam deflection element rotatable about a first axis of rotation

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a second beam deflection element rotatable about a second axis of rotation, wherein the two axes of rotation are perpendicular to each other

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

A first optical arrangement focuses incoming radiation onto the first beam deflection element, and a second optical arrangement focuses the radiation onto the second beam deflection element

Methodology Applied
Scientific EffectFocusing: Focusing

Data Source

PatentEP3326021B1Arrangement and method for two-dimensional deflection of optical radiation
Publication Date: 2021.01.27 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3326021B1 patent drawingFigure 1~2
  • EP3326021B1 patent drawingFigure 3

AI summary

The present invention relates to an arrangement and method for distortion-free, two-dimensional deflection of energy radiation, in particular laser radiation. The arrangement has two beam deflection elements (3, 4) that can be rotatably driven about axes of rotation arranged perpendicular to one another. Coupled-in radiation is projected onto the first beam deflection element (3) using a first optical arrangement (6a, 6b, 10), and onto the second beam deflection element (4) via the first beam deflection element (3) using a second optical arrangement (7a, 7b, 11). The two optical arrangements are thereby dimensioned so that they have a common entrance pupil (2) for the radiation, and beam portions of the incident radiation, which extend at different angles from a center of the entrance pupil (2), respectively strike the first deflection element (3) perpendicular to the first axis of rotation and strike the second deflection element (4) perpendicular to the second axis of rotation. This can be achieved by two cylindrical relay telescopes rotated by 90º to one another with respect to the optical axis. Using the proposed arrangement and the associated method, spatially expanded intensity distributions can be deflected without distortion in two dimensions.