Inline Coherent Imaging for Laser Depth Feedback Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing laser processing technologies face challenges in achieving precise axial control and depth measurement, particularly in heterogeneous materials, leading to issues such as unintended tissue damage and weld failure, due to the instability of keyhole formation and poor metrology in current systems.
Innovation Solution
An apparatus and method utilizing inline coherent imaging (ICI) with an optical interferometer to provide real-time feedback control of laser processing parameters, enabling accurate depth measurement and control of material modification processes by analyzing interferometry output to adjust processing parameters based on subsurface changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard metrology techniques are used to guide laser processing, then quality assurance is provided, but measurement accuracy deteriorates due to plasma generation and electrical interference
Solution Approach 1:
The patent introduces an optical interferometer as an intermediary measurement tool that uses light interference patterns to measure processing depth. This intermediary method avoids direct electrical contact with the plasma environment, eliminating electrical interference issues while providing accurate depth measurement for quality assurance.
Solution Approach 2:
The patent replaces traditional electrical and mechanical measurement systems with optical-based interferometry. This substitution eliminates susceptibility to electrical interference from plasma generation while maintaining measurement capability, thereby preserving both reliability and precision in harsh laser processing environments.
2Manufacturing precision
If laser processing is used for tissue ablation to achieve high transverse control, then transverse precision is improved, but axial control deteriorates leading to unintended tissue damage
Solution Approach 1:
The patent implements real-time feedback control by measuring the actual laser processing depth during operation and comparing it with the target depth. The system adjusts laser parameters dynamically based on this feedback to achieve precise axial control. This resolves the contradiction by providing closed-loop control that compensates for the inherent lack of axial control in focused laser beams.
Solution Approach 2:
The patent applies preliminary anti-action by using optical interferometry to detect the approaching laser processing front before it reaches critical depths. This early detection allows the system to preemptively adjust or terminate laser exposure, preventing unintended tissue damage before it occurs.
3Adaptability or versatility
If laser processing of heterogeneous materials is performed to achieve versatile material modification, then adaptability is improved, but process control deteriorates due to varied material properties
Solution Approach 1:
The patent performs preliminary measurement of the material's optical properties and establishes a processing model before actual laser processing. This preliminary characterization allows the system to predict and compensate for depth variations, improving axial control before the actual cutting or ablation occurs.
Solution Approach 2:
The patent dynamically adjusts laser processing parameters such as pulse energy, pulse duration, and repetition rate based on real-time feedback from optical interferometry. This adaptive parameter modification allows precise control across heterogeneous materials with varying optical and thermal properties, maintaining manufacturing precision while preserving versatility.
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 precise control of laser processing depth and quality assurance, reducing tissue damage and weld defects by using inline coherent imaging to monitor and adjust laser parameters in real-time, ensuring safe and efficient material processing.
Implementation Method 1
An apparatus and method utilizing inline coherent imaging (ICI) with an optical interferometer to provide real-time feedback control of laser processing parameters
Implementation Method 2
Lasers are known to be important tools for processing a wide range of materials. Example processes include welding, drilling, cutting, routing, perforating, sintering and surface treatment
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Methods and systems are provided for using optical interferometry in the context of material modification processes such as surgical laser or welding applications. An imaging optical source that produces imaging light. A feedback controller controls at least one processing parameter of the material modification process based on an interferometry output generated using the imaging light. A method of processing interferograms is provided based on homodyne filtering. A method of generating a record of a material modification process using an interferometry output is provided.