Laser Lens Pivot Axis at Intermediate Focus

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Solution Overview

Problem

Existing laser beam guidance systems for laser processing, particularly in laser joining and hardening, face challenges in precision and compactness due to complex mechanical designs and susceptibility to errors, especially with multiple elastic elements like spiral springs that are inefficient and prone to errors.

Innovation Solution

A device with a pivotable optics system that includes a tactile scanner and a single elastic energy storage element, allowing for precise and compact beam guidance by maintaining a stationary intermediate focal point, reducing the moment of inertia, and using driver stops to provide restoring forces in both pivot directions, thus simplifying the design and enhancing accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple elastic energy storage elements (spiral springs) are used in the rotation module, then the beam deflection module can be restored to rest position, but the device complexity increases and error susceptibility increases

Engineering Contradiction:
Improverestoring force reliabilityVSAvoidrotation module complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates one of the two spiral springs from the rotation module, reducing the elastic energy storage elements from multiple to a single spring. This simplification removes unnecessary complexity while maintaining the restoring force function through the remaining spring combined with the gravitational force on the counterweight

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The restoring force function is segmented between the single elastic energy storage element (spring) and the gravitational force acting on the counterweight. This division allows the system to achieve reliable restoration without requiring multiple springs, thereby reducing complexity while maintaining reliability

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If the entire beam deflection module is swiveled out to track the laser focus, then the laser beam can be directed along the target course, but the moment of inertia increases and tracking speed decreases

Engineering Contradiction:
Improvelaser focus tracking precisionVSAvoidtracking speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The beam deflection module is segmented into a stationary part (housing, protective glass, linear guide) and a movable part (focusing optics). Only the focusing optics need to be swiveled to track the laser focus, while the housing remains stationary. This segmentation dramatically reduces the moment of inertia of the moving mass, enabling faster tracking speed while maintaining precision

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new spatial arrangement where the pivot axis of the focusing optics is positioned at a specific location that allows independent movement of the optics from the housing. This dimensional reorganization enables the optics to move in the required angular direction without moving the entire housing structure

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

3Measurement precision

If the pivot axis does not run through the intermediate focus point, then the housing can be stationary, but the laser focus cannot be tracked precisely

Engineering Contradiction:
Improvefocus tracking precisionVSAvoidoptical path complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by positioning the pivot axis at the specific location of the intermediate focus point. This localized geometric arrangement ensures that when the focusing optics rotate about this axis, the intermediate focus remains stationary while the final focus on the workpiece can be precisely tracked. This specific local configuration simplifies the optical path while maintaining precision

Inventive Principle:
Principle #3Local quality

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 faster, more precise, and cost-effective laser beam tracking with reduced complexity and error susceptibility, allowing for high-quality seam guidance in laser processing without the need for extensive components, leading to improved precision and reduced processing time.

Implementation Method 1

an elastic element, which provides part of its stored energy as a function of a pivoting out of the pivotable optics for resetting the optics and scanner in a rest position

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2599574B1Laser lens with passive seam tracking
Publication Date: 2016.11.30 SCANSONIC MI
  • EP2599574B1 patent drawingFigure 1
  • EP2599574B1 patent drawingFigure 2
  • EP2599574B1 patent drawingFigure 3

AI summary

The device comprises a laser beam input module that is formed to direct an incident laser beam on the laser beam input module and a pivotable beam guiding device, where the beam guiding device is arranged for projecting the laser beam on a target course and comprises a pivotable optics (5) along a pivot axis (4) and a tactile scanner (6) connected to the pivotable optics. The tactile scanner is designed to scan the target course and to deflect the pivotable optics. An intermediate focus point is formed in a beam path of the laser beam in front of the pivotable optics. The device comprises a laser beam input module that is formed to direct an incident laser beam on the laser beam input module and a pivotable beam guiding device, where the beam guiding device is arranged for projecting the laser beam on a target course and comprises a pivotable optics (5) along a pivot axis (4) and a tactile scanner (6) connected to the pivotable optics. The tactile scanner is designed to scan the target course and to deflect the pivotable optics. An intermediate focus point is formed in a beam path of the laser beam in front of the pivotable optics. The pivot axis of the pivotable optics extends through the intermediate focus point. The laser beam input module is adapted to focus the laser beam onto the intermediate focal point. The pivotable optics is designed to image the intermediate focal point on the target course. The laser beam input module comprises an optical fiber, and an intermediate imaging optics. The intermediate imaging optics: is designed to map an end of the optical fiber on the intermediate focal point; and is formed on a side of the optical fiber facing the pivotable optics that is designed to form the intermediate focal point on the target course. The laser beam input module is further designed to generate a non-focused beam. The pivotable optics has a virtual intermediate focus that is located in the collimated beam path. The tactile scanner and the pivotable optics are connected to an energy store with an elastic element. The elastic element of the energy store is formed to provide a portion of its stored energy depending on a swivel out (alpha ) of the pivotable optics for the resetting of optics and the scanner in a rest position. The optics and the scanner are coupled via two driver stops of the elastic element, by which a first driving stop of the elastic element is deformed with the pivotable optics in a positive pivot axis direction and a second driver stop of the elastic element is deformed with the pivotable optics in a negative pivot axis direction. The elastic element: is formed in a one-piece manner; is mounted on a housing having two stationary stop faces; and is pressed against a first stop face with a deflection in the positive pivot axis direction and against a second stop face with a deflection in the negative pivot axis direction. One of the two stop faces and/or one of the driver stops is adjustably arranged in a deformation direction of the elastic element. The elastic element is a mechanical spring having pressure discs on both ends, where the pressure discs, the driver stops and the stationary stop surfaces are formed in a dome-shaped manner. The scanner is spring-mounted in a laser beam direction over an elastic component. The laser beam input module is coupled to the elastic component. The pivotable optics is rigidly connected to the scanner comprising a seaming required for filler wire.