Interferometric Measurement Module With Adjustable Optical Path Length
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Solution Overview
Problem
Existing laser processing systems face challenges in maintaining accurate and reliable distance measurements due to variability in the optical path length, which affects the focus of the laser beam, leading to irregularities in the final product quality, and current solutions like optical coherent tomography are costly and complex.
Innovation Solution
A modular measurement module with an interferometer system that includes a housing, connection ports, and an optical path length regulator system to adjust the optical path length of the measurement beam, allowing for continuous and accurate distance determination, independent of variations in the laser processing system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical coherent tomography is used for distance measurement, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex optical coherent tomography systems with a simplified interferometric measurement module that uses a beam splitter, reference mirror, and detector to achieve accurate distance measurements through optical interference patterns, eliminating the need for complex tomographic reconstruction algorithms and hardware
Solution Approach 2:
The patent extracts only the essential interferometric measurement functionality from complex optical coherent tomography systems, isolating the core distance measurement capability using minimal optical components (beam splitter, reference mirror, detector) while discarding unnecessary complexity
2Adaptability or versatility
If adjustable focusing system is used to overcome f-theta-lens limitations, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent integrates the interferometric measurement module into the existing laser processing optical path, allowing the same optical components (deflection mirrors, lenses) to serve both work beam delivery and measurement beam guidance functions, achieving multi-functionality without adding separate focusing mechanisms
Solution Approach 2:
The patent merges the measurement optical path with the work beam optical path by using a beam splitter to combine both beams in the same physical space, allowing shared use of deflection mirrors and focusing lenses for both measurement and processing functions
3Ease of operation
If measurement beam optical path length varies with deflection system settings, then ease of operation is improved, but measurement precision deteriorates
Solution Approach 1:
The patent uses the interferometric detector to provide real-time feedback on optical path length differences caused by deflection system variations, enabling the system to compensate for path length changes and maintain measurement precision despite deflection mirror movements
Solution Approach 2:
The patent compensates for optical path length variations by dynamically adjusting measurement parameters based on feedback from the interferometric detector, maintaining measurement accuracy despite changes in deflection system configuration
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 ensures precise and reliable distance measurements by maintaining a constant optical path length difference, enabling accurate focus control without reconfiguring the focusing system, thus improving the quality of laser processing.
Implementation Method 1
distance detection device configured to measure distances, in particular distances between the laser processing module or the deflection unit thereof and the surface of a workpiece being laser-processed
Data Source
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AI summary
The invention refers to a measurement module (10) for a laser processing apparatus (1) in which a first optical path (P1) and a second optical path (P2) are defined for laser light within a housing (11). The first optical path (P1) has a fixed predefined optical path length. The second optical path (P2) is defined between a connection port (12) of the housing and a coupling port (14) and has a variable optical path length adjustable by an optical path length regulator system (20). The invention further refers to an interferometer system comprising a measurement module with a first optical path (P1) corresponding to a reference arm of the interferometer system and with a second optical path (P2) corresponding to an object arm of the interferometer system, wherein an optical path length regulator system (20) is configured for adjusting an optical path length of the second optical path (P2), i.e., of the object arm of the interferometer system. The measurement module (10) further comprises a focusing device (18) arranged in the second optical path (P2) between the connection port (12) and the optical path length regulator system (20) and configured for focusing the laser light transmitted through the second optical path (P2). The invention further refers to a laser processing apparatus (1) comprising a laser processing module (30) for laser-processing a workpiece (P) on a work field (37) using a work beam (W) and a measurement module (10) according to the invention.