Beam Shaping Unit for Laser Focus Diameter and Position Adjustment

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Solution Overview

Problem

Current laser material processing systems face productivity limitations due to the need for frequent adjustments in focus diameter and position, which often require exchanging optics or processing heads, resulting in complex setups and reduced flexibility.

Innovation Solution

A beam shaping unit with a first and second optical element, where the first element adjusts focus diameter via movement along the optical axis and the second element adjusts focus position, either through movement or curvature change, allowing for flexible and extended adjustment ranges with a simpler structure, and a control unit for precise setting using application-specific and current correction values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an adaptive mirror is used to adjust focus position, then the focus position can be adjusted via variable radius of curvature, but the adjustment range is limited to less than 10 mm and the design becomes more complex

Engineering Contradiction:
Improvefocus position adjustment capabilityVSAvoiddesign complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The beam shaping unit is divided into multiple optical elements (first optical element for focus diameter adjustment, second optical element for focus position adjustment) with independent focus setting devices. This segmentation allows each element to be optimized for its specific function, enabling extended focus position adjustment range without requiring a single complex adaptive mirror system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs dynamic adjustment mechanisms where the first optical element can be moved along the optical axis to adjust focus diameter, and the second optical element can be moved or have its curvature changed to adjust focus position. These dynamic elements provide flexible, extended adjustment ranges beyond the limitations of static or singly-adjustable systems.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the focusing optics are made movable to adjust focus position, then the focus position can be adjusted in accordance with focus diameter change, but precise guide elements and sealing elements are required resulting in complex structure

Engineering Contradiction:
Improvefocus position adjustment rangeVSAvoidbeam guidance system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Instead of making the entire focusing optics assembly movable with complex guides and seals, the patent segments the system into a first optical element for diameter adjustment and a second optical element for position adjustment. This segmentation allows for simpler, more manageable adjustment mechanisms with reduced structural complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces complex mechanical guide and sealing systems with alternative approaches, such as using optical elements with variable curvature or simplified movement mechanisms that achieve the same focus position adjustment without requiring precise mechanical guides and hermetic sealing.

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

3Adaptability or versatility

If optics exchange is performed to adjust focus parameters, then different process requirements can be met, but set-up times increase reducing productivity

Engineering Contradiction:
Improveprocess adaptation capabilityVSAvoidproductivity
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The beam shaping unit is designed as a universal system with multiple optical elements that can be dynamically adjusted to meet different process requirements. Instead of requiring separate optics for different applications, this multi-functional unit can adapt to various focus diameter and position requirements through its adjustable elements, eliminating the need for optics exchange and improving productivity.

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

Solution Approach 2:

The system employs dynamic adjustment capabilities where optical elements can be moved or have their curvature changed during operation to adapt to different processing requirements. This dynamic adaptability replaces static optics exchange with continuous adjustment, significantly reducing set-up times and improving productivity.

Inventive Principle:
Principle #15Dynamics

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 flexible and precise adjustment of focus diameter and position over a larger range, reducing setup times and complexity, while maintaining image quality and sealing integrity, thereby enhancing productivity and ease of use in laser material processing.

Implementation Method 1

a first optical element on which a laser beam impinges, a second optical element, which is arranged downstream of the first optical element in the direction of beam propagation... the laser beam is imaged by the first optical element via an intermediate focus on the second optical element

Methodology Applied
Scientific EffectOptical focusing: Focusing

Implementation Method 2

the second optical element has a second focus setting device for setting a focus position in the direction of beam propagation of the laser beam by influencing the second optical element

Methodology Applied
Scientific EffectOptical focusing: Focusing

Data Source

PatentEP2560783B1Beam shaping unit for focusing a laser beam and method of operating the same
Publication Date: 2017.05.31 TRUMPF WERKZEUGMASCHINEN GMBH & CO KG
  • EP2560783B1 patent drawingFigure 1a~1c
  • EP2560783B1 patent drawingFigure 2

AI summary

The invention relates to a beam-forming unit (1) for focussing a laser beam (3) on a workpiece (9) for laser machining, comprising: a first optical element (5) which the laser beam (3) strikes, a second optical element (7) which is arranged downstream of the first optical element (5) in the beam propagation direction, and focussing optics (8) arranged downstream of the second optical element (7) in the beam propagation direction, wherein a first focus setting device (10) for setting a focus diameter (D) by influencing the first optical element (5) is assigned to the first optical element (5), wherein a second focus setting device (12) for setting a focus length in the beam propagation direction of the laser beam (3) by influencing the second optical element (7) is assigned to the second optical element (7), and wherein the laser beam (3) is reproduced on the second optical element (7) by the first optical element (5) via an intermediate focus (6). The invention also relates to a method for activating the beam-forming unit (1).