Laser Process Sensor with Wavelength-Split Error Detection
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Solution Overview
Problem
Existing laser processing monitoring systems fail to detect process errors due to broadband spectral sensitivity of photodiodes, which mask intensity changes within individual wavelength ranges, leading to undetected defects in processes like laser welding.
Innovation Solution
A sensor device that splits the process beam into multiple, non-overlapping wavelength ranges using a beam splitter arrangement, allowing individual detection and amplification of sensor signals for each range, with optimized imaging and aperture sizes for precise monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If broadband spectral sensitivity of photodiodes is used for detection, then the overall intensity measurement is simplified, but the detection precision of intensity changes within individual wavelength ranges deteriorates
Solution Approach 1:
The broadband spectral range is segmented into multiple discrete wavelength ranges using beam splitters with specific reflection and transmission characteristics. Each wavelength range is directed to a separate photodiode, enabling independent intensity measurement for each segment. This segmentation resolves the contradiction by maintaining relatively simple device structure while achieving high measurement precision through separate detection channels.
2Adaptability or versatility
If integrated intensity measurement over large wavelength range is performed, then the monitoring coverage is comprehensive, but the detection capability for specific wavelength changes deteriorates
Solution Approach 1:
The comprehensive spectral range is divided into multiple wavelength segments, each monitored by dedicated photodiodes. This allows the system to maintain broad monitoring coverage while simultaneously detecting intensity changes in specific wavelength ranges with high precision, as each segment can be independently evaluated.
Solution Approach 2:
Different wavelength ranges are assigned to different detection channels with optimized characteristics. Each photodiode measures the intensity in its specific wavelength range independently, allowing local optimization of detection quality for each spectral region while maintaining overall comprehensive coverage.
3Measurement precision
If separate detection for multiple wavelength ranges is implemented, then the process error detection precision is improved, but the device complexity increases
Solution Approach 1:
The detection system is segmented into multiple independent channels, each handling a specific wavelength range. This segmentation improves process error detection precision by enabling wavelength-specific analysis while keeping each individual channel relatively simple in structure.
Solution Approach 2:
Multiple photodiodes detecting different wavelength ranges are merged into a single integrated sensor device with a unified beam splitter arrangement. This combining approach achieves high measurement precision through separate wavelength detection while avoiding excessive device complexity by integrating all components into one cohesive system.
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 more precise detection of process errors by separately monitoring and amplifying sensor signals across different wavelength ranges, improving the accuracy of laser processing quality control.
Implementation Method 1
a beam splitter arrangement (28) configured to extract several visible partial beams (38a, 38b, 40a, 40b) with different visible wavelength ranges from the process beam (16)
Implementation Method 2
a first photosensor arrangement (42) for detecting an intensity of the process beam in the visible wavelength range, comprising several photosensors (42a-42d) arranged to detect an intensity of each of the visible partial beams
Data Source
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AI summary
The present application discloses a sensor device for monitoring a laser processing process by means of a laser beam by detecting the intensity of a process beam generated during the laser processing process, the sensor device comprising: an optical input for introducing the process beam; a beam splitter arrangement configured to couple several visible partial beams with respective visible wavelength ranges from the process beam; a first photosensor arrangement for detecting the intensity of the process beam in the visible wavelength range with several photosensors arranged to each detect an intensity of one of the visible partial beams, wherein the beam splitter arrangement is configured to detect a first visible partial beam with a first visible wavelength range, a second visible partial beam with a second visible wavelength range,to couple a third visible partial beam with a third visible wavelength range and a fourth visible partial beam with a fourth visible wavelength range to a photosensor of the first photosensor arrangement, wherein the first photosensor arrangement comprises: a first photosensor arranged to detect an intensity of the first visible partial beam, a second photosensor arranged to detect an intensity of the second visible partial beam, a third photosensor arranged to detect an intensity of the third visible partial beam (40a), and a fourth photosensor arranged to detect an intensity of the fourth visible partial beam. Furthermore, a laser processing system with the sensor device is disclosed.