Laser Beam Characterization for Adaptive Spot Size Control
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Solution Overview
Problem
Conventional laser-processing apparatuses face challenges in maintaining consistent laser spot size and shape due to environmental factors like temperature fluctuations, mechanical vibrations, and optical contamination, leading to variations in processing quality and productivity.
Innovation Solution
Incorporating a beam characterization tool that measures and adjusts laser beam characteristics in real-time, using a combination of acousto-optical deflectors, resonant scanning mirrors, and advanced optical filters to ensure precise control over beam size, shape, and power, allowing for adaptive processing of workpieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional laser-processing apparatuses are used without real-time beam characterization, then the device complexity is lower, but the manufacturing precision and reliability deteriorate due to variations in laser spot size and shape caused by environmental factors
Solution Approach 1:
The laser beam is split into multiple portions using beam splitters, with one portion directed to the workpiece and another to the beam characterization tool. This segmentation allows simultaneous processing and real-time beam measurement without interfering with the main processing path.
Solution Approach 2:
A beam characterization tool is introduced as an intermediary device to measure beam characteristics (spot size, shape, power) in real-time. This mediator provides feedback information that enables dynamic compensation for environmental variations, improving manufacturing precision.
2Reliability
If robust optics designs and alignment practices are used to reduce spot size variations, then the reliability improves, but the device complexity and ease of manufacture worsen
Solution Approach 1:
The beam characterization tool provides real-time feedback on beam parameters, which is used to dynamically adjust processing parameters or compensate for variations. This feedback mechanism maintains reliability without requiring complex robust optics designs or difficult alignment procedures.
3Reliability
If process recipes are made more robust to accommodate spot characteristic variations, then the reliability improves, but the productivity deteriorates due to the inverse relationship between robustness and speed
Solution Approach 1:
The system transitions from static process recipes to dynamic adaptive processing. Real-time beam characterization data enables continuous adjustment of processing parameters, maintaining quality consistency while allowing high processing speeds without the need for overly conservative robust recipes.
4Productivity
If out-of-focus laser spots are used to increase processing area, then the productivity improves, but the manufacturing precision worsens due to increased variation in effective spot size
Solution Approach 1:
Real-time beam characterization provides feedback on the actual spot size and shape, enabling dynamic compensation for the increased variations inherent in out-of-focus processing. This allows larger processing areas to be covered while maintaining manufacturing precision through active control.
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 robust and efficient laser processing by maintaining consistent beam characteristics, improving processing quality and productivity while accommodating variations in the laser system and workpiece materials.
Implementation Method 1
an acousto-optical deflector (AOD) arranged within the beam path and operative to deflect the beam path along which the beam of laser energy is propagatable
Implementation Method 2
a resonant scanning mirror system arranged and configured to deflect the beam of laser energy, as deflected by the AOD, along the axis, in a sinusoidal manner as a function of time
Implementation Method 3
an optical filter arranged between the token and the photodetector, the optical filter configured to attenuate laser energy transmitted by the substrate such that the beam of laser energy transmitted by the optical filter irradiates the photodetector at a fluence less than a threshold fluence
Data Source
AI summary
Apparatus and techniques for laser-processing workpieces can be improved, and new functionalities can be provided. Some embodiments discussed relate to use of beam characterization tools to facilitate adaptive processing, process control and other desirable features. Other embodiments relate to laser power sensors incorporating integrating spheres. Still other embodiments relate to workpiece handling systems capable of simultaneously providing different workpieces to a common laser-processing apparatus. A great number of other embodiments and arrangements are also detailed.