Laser Reflectance Sensing with Modulated Spot Power Density
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Solution Overview
Problem
Existing laser processing methods face challenges in acquiring reflectance while minimizing damage to the workpiece, as the output for reflectance detection is often lower than that required for forming a modified layer, and the specific configuration for achieving this is unclear.
Innovation Solution
A laser processing device that employs a spatial light modulator to lower the power density of the laser light on the workpiece during reflectance acquisition, using modulation patterns such as shift patterns or spot deformation patterns to control the converging point and spot shape, allowing for reflectance measurement without damaging the object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the output of the laser beam is increased to acquire reflectance, then the measurement precision is improved, but the workpiece may be damaged
Solution Approach 1:
The patent applies dynamics by making the laser beam output adjustable and variable. The laser processing device can dynamically change the output power of the laser beam based on the processing stage: using lower output during reflectance detection to avoid damage, and higher output during modified layer formation to achieve processing goals. This dynamic adjustment resolves the contradiction between measurement precision and workpiece damage.
Solution Approach 2:
The patent changes the parameter of laser beam output power to resolve the contradiction. By adjusting the output parameter of the laser beam, the system can operate at different power levels: lower power for safe reflectance measurement and higher power for effective modified layer formation, thus eliminating the fixed trade-off between measurement accuracy and workpiece safety.
2Object-affected harmful factors
If the output of the laser beam is decreased to suppress damage to the workpiece, then the safety is improved, but the measurement precision of reflectance is reduced
Solution Approach 1:
The system uses dynamic output adjustment where the laser beam power is set to an appropriate lower level specifically for reflectance detection, and then increased to a higher level for modified layer formation. This dynamic switching allows the system to maintain measurement precision at the detection stage while ensuring workpiece safety, resolving the contradiction between safety and measurement precision.
Solution Approach 2:
The patent changes the laser beam output parameter to resolve the contradiction. By adjusting the output parameter to suitable levels for different processing stages, the system achieves both workpiece protection during detection and adequate signal strength for accurate reflectance measurement, eliminating the fixed trade-off between safety and measurement quality.
3Manufacturing precision
If a specific configuration is implemented to realize the laser processing method, then the manufacturing precision is improved, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing a laser processing device that performs multiple functions: reflectance detection, modified layer formation, and output adjustment. This multi-functional device integrates what would otherwise be separate systems, achieving high manufacturing precision while managing device complexity through functional integration rather than adding separate dedicated systems.
Solution Approach 2:
The patent uses parameter changes to achieve manufacturing precision without excessive complexity. By adjusting the output parameter of the laser beam based on the processing stage, the system achieves precise control over the modified layer formation process without requiring complex additional hardware, resolving the contradiction between manufacturing precision and device complexity.
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 the acquisition of reflectance while preventing damage to the object being processed by adjusting the power density of the laser light, thereby expanding the dynamic range of measurable reflectance.
Implementation Method 1
a spatial light modulator configured to modulate the laser light according to a modulation pattern
Implementation Method 2
a converging unit configured to converge the laser light toward the first surface to form a converging point
Implementation Method 3
imaging the reflected light of the laser light by controlling the camera to acquire a reflectance of the first surface
Data Source
AI summary
Disclosed is a laser processing device including a laser light source configured to output laser light, a converging unit configured to converge the laser light toward a first surface to form a converging point, a camera configured to image reflected light of the laser light from the first surface, a spatial light modulator for modulating the laser light according to a modulation pattern, and a controller configured to execute acquisition processing of applying the laser light to the first surface by controlling the laser light source and imaging the reflected light by controlling the camera to acquire a reflectance of the first surface for the first wavelength.