Laser Soldering Spectral Monitoring for Substrate Burn Detection
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Solution Overview
Problem
Existing laser soldering processes face challenges in reliably and cost-effectively monitoring substrate burning during the process due to insufficient temporal and spatial resolution of thermographic cameras, which fail to distinguish between normal soldering and substrate damage.
Innovation Solution
A method using a spectroscope device to analyze the light signal formed during laser soldering, dispersing it into a spectrum for identifying substrate burning by distinguishing between substrate-independent normal and substrate-dependent burning portions based on characteristic parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermographic camera is used to monitor the laser soldering process, then the monitoring capability is provided, but the temporal and spatial resolution is insufficient to distinguish between normal soldering and substrate burning
Solution Approach 1:
The patent replaces the thermographic camera (optical imaging system) with a photodiode array system that detects light intensity at multiple wavelengths. This substitution enables precise measurement of light signal characteristics without the temporal and spatial resolution limitations of thermographic imaging, allowing reliable distinction between normal soldering and substrate burning through spectral analysis rather than thermal imaging
Solution Approach 2:
The patent changes the monitoring parameter from thermal radiation distribution (spatial temperature map) to light intensity at specific wavelengths (spectral characteristics). By analyzing the intensity ratio of light signals at different wavelengths, the system achieves high measurement precision in distinguishing soldering states without requiring high temporal and spatial resolution imaging capability
2Measurement precision
If a thermographic camera with improved temporal and spatial resolution is used, then the measurement precision is improved, but the cost increases significantly
Solution Approach 1:
The patent employs a photodiode array system with multiple photodiodes that detect light intensity at different wavelengths. This approach uses inexpensive optical components and simple electronic sensors instead of expensive high-resolution thermographic cameras, achieving the required measurement precision at a fraction of the cost while maintaining reliable monitoring capability
Solution Approach 2:
The patent replaces the expensive thermographic imaging system with a simpler photodiode-based optical detection system. This substitution eliminates the need for costly high-resolution thermal cameras while providing sufficient measurement precision through spectral intensity analysis, thereby reducing manufacturing cost significantly
3Ease of operation
If the light signal intensity is monitored without spectral analysis, then the detection simplicity is maintained, but the ability to distinguish between normal and burning light signals is lost
Solution Approach 1:
The patent changes the detection approach from monitoring total light intensity (single parameter) to measuring light intensity at multiple specific wavelengths (multiple parameters). By analyzing the intensity ratio between different wavelengths, the system preserves detection simplicity through straightforward intensity measurements while avoiding information loss through spectral composition analysis
Solution Approach 2:
The patent segments the light signal detection into multiple wavelength channels using a photodiode array. Each photodiode detects light intensity at a specific wavelength range, allowing the system to analyze the spectral composition of the light signal. This segmentation enables distinction between normal and burning states by comparing intensity ratios across different wavelength segments
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 reliable and inexpensive monitoring of laser soldering processes by differentiating between normal and burning-related light signals, allowing for timely intervention to prevent further substrate damage.
Implementation Method 1
the light signal is dispersed into a spectrum of the light signal by means of a spectroscope device of the monitoring device
Data Source
AI summary
A laser soldering system and a method for monitoring a laser soldering process by means of a monitoring device of the laser soldering system, wherein a solder ball is dispensed onto a solderable surface of a substrate by means of a solder ball feeding device of the laser soldering system, wherein the solder ball is at least partially melted by means of a laser device of the laser soldering system, wherein, during the laser soldering process, a light signal is formed which is detected by means of an optical detection unit of the monitoring device, wherein the light signal is dispersed into a spectrum of the light signal by means of a spectroscope device of the monitoring device, wherein the spectrum is analyzed by means of a processing device of the monitoring device, and it is identified on the basis of a composition of the spectrum whether or not a burning of the substrate has occurred during the laser soldering process.