Laser Processing Optics for Return Light Detection and Source Protection
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Solution Overview
Problem
Existing laser processing devices face challenges in accurately detecting return light reflected from metal processing objects, which can cause failure in the laser light source due to its reflection back into the optical fiber and laser source.
Innovation Solution
A laser processing device is designed with a separate light source for inspection using a different wavelength, an optical waveguide, and a detector to accurately detect return light, utilizing dichroic mirrors to manage optical paths and prevent return light from reaching the processing laser source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a detection unit is arranged on a processing head close to the processing object, then the reflection of the laser light by the processing object can be detected, but whether the return light propagates an optical path and enters the laser light source cannot be correctly detected
Solution Approach 1:
A wavelength conversion element (non-linear optical crystal) is introduced as an intermediary to convert the wavelength of the return light before it reaches the detector. This allows the detector to specifically detect return light at a different wavelength from the processing laser, enabling accurate detection of return light path information without interference from the processing laser light.
Solution Approach 2:
The optical path is segmented into different wavelength channels. The processing laser operates at one wavelength while the return light detection uses a converted wavelength channel. This segmentation allows simultaneous processing and detection without mutual interference, solving the problem of detecting return light path information.
2Reliability
If return light is not detected and prevented, then the laser light source may fail due to return light incidence, but no mechanism exists to detect and prevent this failure
Solution Approach 1:
A feedback mechanism is implemented where the detector continuously monitors for return light at the converted wavelength. When return light is detected, the control unit receives feedback and automatically adjusts the processing head position or stops the processing laser output, preventing damage to the laser source and ensuring reliable operation.
Solution Approach 2:
The system performs preliminary detection of return light using the wavelength conversion and detection mechanism before the return light can cause damage. The control unit takes preliminary protective actions by adjusting the processing head position or stopping laser output when return light is detected, preventing laser source failure before it occurs.
3Reliability
If the processing head position is adjusted to prevent return light, then laser source failure can be avoided, but processing efficiency is reduced due to frequent position adjustments
Solution Approach 1:
The system replaces mechanical position adjustment with optical wavelength conversion and detection. Instead of frequently moving the processing head to avoid return light, the system uses non-linear optical wavelength conversion to enable detection of return light at a different wavelength, allowing the processing head to maintain optimal position while the control unit monitors and responds to return light conditions.
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
This setup allows for precise detection of return light, preventing laser source failure by stopping the output of the processing laser and enabling effective measures to mitigate return light interference, thus ensuring accurate and reliable laser processing.
Implementation Method 1
an optical waveguide in which the laser light for processing and the laser light for inspection are incident from an incident surface and the laser light for processing and the laser light for inspection are emitted from an emission surface toward a processing object
Implementation Method 2
a return light of the laser light for inspection reflected by the processing object, incident from the emission surface of the optical waveguide
Data Source
AI summary
Provided is a laser processing device capable of detecting that a return light of a laser light reflected by a processing object is incident on a laser light source. The laser processing device includes: a laser light source which outputs a laser light for processing; a light source for inspection which outputs a laser light for inspection having a wavelength different from that of the laser light for processing; an optical waveguide in which the laser light for processing and the laser light for inspection are incident from an incident surface, and the laser light for processing and the laser light for inspection are emitted from an emission surface toward a processing object; and a detector which detects a return light of the laser light for inspection reflected by the processing object, incident from the emission surface of the optical waveguide and emitted from the incident surface.