Optical Horned Lightpipe for Laser Welding Beam Convergence
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Solution Overview
Problem
Conventional Through-Transmission Infrared (TTIr) welding systems using lightguides or lightpipes result in oversized welding zones due to the dispersion of laser light, which cannot be effectively minimized by conventional means, leading to larger than desired weld areas.
Innovation Solution
A laser welding apparatus incorporating a lightpipe or lightguide with a narrowing tapered waveguide and an optical horn that converges the zero and first order light lobes, optimizing the beam width to achieve a narrower weld zone by reflecting first order lobes into the zero order lobe, thereby concentrating the laser energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional lightguide or lightpipe is used to transmit laser beam, then the laser beam can be transmitted through the transmissive piece, but the infrared laser light exits the lightguide in a fan or cone shape causing dispersion and oversized welding zones
Solution Approach 1:
The invention segments the transmitted laser beam into multiple discrete beams using a diffractive optical element. Instead of a single dispersed beam, the light is divided into several focused beams that can be independently controlled to converge at a specific focal point, thereby reducing the overall welding zone area while maintaining effective welding energy concentration.
Solution Approach 2:
The invention transforms the spatial distribution of the laser beam from a two-dimensional fan or cone shape into a focused three-dimensional convergence at a focal point. By using diffractive optics to create multiple beams that converge in space, the energy is concentrated in a smaller volumetric region, reducing the welding zone area while improving precision.
2Use of energy by moving object
If the laser beam is transmitted through a conventional lightguide, then the beam can reach the welding zone, but the light disperses outwardly impacting a larger area of the absorptive piece and transmissive piece interface
Solution Approach 1:
The laser energy is segmented into multiple discrete beams that are individually directed and converged. This segmentation allows each beam to maintain its energy concentration while collectively covering the welding zone, reducing overall energy dispersion and improving energy utilization efficiency at the focal point.
Solution Approach 2:
A diffractive optical element is introduced as an intermediary between the lightguide and the workpiece. This intermediary component transforms the dispersed beam into multiple focused beams, mediating the energy transfer to minimize dispersion and maximize energy concentration at the welding zone, thereby improving overall energy utilization.
3Device complexity
If a conventional lightguide is used, then the system structure remains simple, but the beam width cannot be narrowed below the initial beam width defined by the lightguide exit
Solution Approach 1:
A diffractive optical element is introduced as a relatively simple intermediary component that can be integrated into the existing lightguide system. This element provides advanced beam control capabilities including width reduction and focal point convergence without requiring complex optical systems, maintaining device simplicity while improving manufacturing precision.
Solution Approach 2:
The invention changes the optical parameters of the laser beam by introducing a diffractive element that modifies the beam's wavefront, directionality, and convergence properties. This parameter change enables the beam width to be narrowed below the initial lightguide exit width, achieving better precision without proportionally increasing system complexity.
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
The solution achieves a significantly narrower weld zone, reducing the weld width by seven times compared to conventional systems, enabling more precise and efficient welding operations.
Implementation Method 1
an optical horn that converges the zero and first order light lobes, optimizing the beam width to achieve a narrower weld zone by reflecting first order lobes into the zero order lobe
Implementation Method 2
a light transmitting device being positioned downstream from the laser source. The light transmitting device transmits the laser beam therethrough
Implementation Method 3
the second plastic part is often referred to as absorptive piece, since this piece generally absorbs the radiative energy of the laser beam to produce heat in the welding zone
Implementation Method 4
lasers provide a semi-focused beam of electromagnetic radiation at a specified frequency (i.e., coherent monochromatic radiation
Data Source
AI summary
A laser welding apparatus having a laser source outputting a laser beam and a light transmitting device being positioned downstream from the laser source. The light transmitting device transmits the laser beam therethrough. The laser beam exiting the light transmitting device has at least a zero order light lobe and a first order light lobe, wherein the zero order light lobe and the first order light lobe together defining an initial beam width. An optical device positioned downstream from the light transmitting device converges the first order light lobe with the zero order light lobe to define a final beam width that is narrower than the initial beam width.