Eccentric Rotating Lens for High-Speed Laser Beam Trajectory Control

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Solution Overview

Problem

Existing laser welding methods using fiber-fed boxes struggle to control the trajectory of the laser beam for complex patterns like circular, helical, or scalloped trajectories due to the inertia of traditional galvanometric mirrors, limiting speed and precision in spot welding and other applications.

Innovation Solution

A device with a rotating lens mechanism that allows controlled eccentricity and angular position adjustments, enabling the laser beam to describe complex trajectories without relying on traditional mirrors, using a driven mechanism with a motor, electronic control, and a rechargeable battery for precise beam control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If traditional galvanometric mirrors are used to control laser beam trajectory, then the system structure is simple, but the trajectory control speed and precision deteriorate due to mirror inertia

Engineering Contradiction:
Improvetrajectory control speedVSAvoidguiding system complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent replaces the traditional mechanical galvanometric mirror system with an optical fiber-based laser delivery system. The laser beam is transmitted through an optical fiber to a scanning system that uses prisms and lenses instead of rotating mirrors, eliminating the inertia problem and enabling faster trajectory control while maintaining system manageability.

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

Solution Approach 2:

The patent introduces an optical fiber as an intermediary between the laser source and the scanning system. This fiber acts as a flexible transmission medium that decouples the laser source from the scanning mechanism, allowing independent optimization of both components and enabling faster response times without increasing overall system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If galvanometric mirrors are used for high-speed trajectory control, then speed improves, but precision deteriorates due to inertia effects

Engineering Contradiction:
Improvewelding speedVSAvoidtrajectory precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces the inertia-prone galvanometric mirror system with an optical fiber delivery system combined with a prism-based scanning mechanism. This substitution eliminates the trade-off between speed and precision by using a system where the scanning elements have negligible inertia, allowing high welding speeds while maintaining accurate trajectory control through electronic positioning of the optical components.

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

3Adaptability or versatility

If traditional mirror-based laser guidance is used, then the system is easier to operate, but the ability to describe complex trajectories deteriorates

Engineering Contradiction:
Improvetrajectory pattern capabilityVSAvoidsystem operation simplicity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent uses an optical fiber as an intermediary that provides flexibility in positioning the laser source while maintaining a compact scanning system. This allows the system to achieve complex trajectory patterns including circles, ellipses, and scalloped paths through software control of the prism angles, without complicating the physical operation of the system.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements a dynamic scanning system using prisms that can be rapidly repositioned to change the laser beam path. This dynamic optical system, controlled by electronic actuators, enables the laser to trace complex patterns at high speeds while maintaining ease of operation through software-based trajectory programming rather than mechanical reconfiguration.

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 high-speed, precise control of laser beam trajectories for circular, helical, and scalloped patterns, improving welding precision and efficiency by decoupling from mirror inertia, allowing for faster rotation and more accurate spot welding.

Implementation Method 1

The housing comprises a simple or complex lens, configured to shape a beam of laser light arriving on the lens from the laser source

Methodology Applied
Scientific EffectLens focusing: Lens

Implementation Method 2

the housing comprising a simple or complex lens, configured to shape a beam of laser light arriving on the lens from the laser source. The housing further comprises a driven mechanism for rotating the lens about a first axis parallel to the optical axis of the lens, and spaced from the optical axis of the lens

Methodology Applied
Scientific EffectEccentric rotation: Eccentric

Data Source

PatentEP3515650B1Device and method for guiding a laser beam with a view to rotational and linear displacement, in order to vary the eccentricity of the laser beam
Publication Date: 2021.08.04 RENAULT SA
  • EP3515650B1 patent drawingFigure 1
  • EP3515650B1 patent drawingFigure 2~4
  • EP3515650B1 patent drawingFigure 3

AI summary

The invention relates to a device and a method for guiding an impact trajectory of a laser beam (C) exiting from a housing (2), in which a lens (10) is used to collimate a laser beam (A) arriving from a laser source and entering the housing, the lens (10) is made to rotate about an axis (ω, x) eccentric relative to the optical centre (0) of the lens, and a progressive, controlled variation in the offset (5) of the lens (10) is achieved, sometimes during rotation of the lens (10) and sometimes for a given angular position of the lens (10).