Laser Fiber Failure Detection Using Dual-Light Intensity Ratios
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Solution Overview
Problem
Existing disconnection detection devices in laser processing systems face issues with erroneous detection due to factors like friction, changes in gas flow, and fluctuations in laser light intensity, making it difficult to accurately detect optical fiber disconnection and other defects.
Innovation Solution
A failure detection device that uses a processing laser light source and a detection laser light source, along with an optical fiber equipped with mode stripper units, to transmit detection laser light and processing laser light. This device employs multiple photoreceivers to measure light intensities and a determination unit to assess relative ratios and temporal changes, enabling accurate detection of defects in the optical fiber, condensing lens, laser head, and processing target.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coated electric wires are used for disconnection detection, then the detection function is provided, but erroneous detection occurs due to friction or short-circuit
Solution Approach 1:
The patent introduces a protective coating on the electric wires that acts as an intermediary layer. This coating prevents direct contact between the wires and the optical fiber, eliminating friction-induced short-circuits and false detections while maintaining the electrical continuity needed for detection functionality.
Solution Approach 2:
The patent replaces the mechanical contact-based detection system (coated electric wires relying on physical contact) with an optical-based detection system. By using light transmission through the optical fiber and detecting changes in light properties, the system eliminates mechanical friction and contact-related erroneous detections.
2Reliability
If gas circulation tube is used for disconnection detection, then the detection function is provided, but erroneous detection occurs due to gas flow rate changes
Solution Approach 1:
The patent uses light as an intermediary to detect disconnection, replacing the gas circulation method. By monitoring light transmission properties rather than gas flow rate, the system eliminates errors caused by gas flow variations while maintaining effective disconnection detection.
3Device complexity
If processing laser light intensity is used for detection, then the existing laser system is utilized, but detection accuracy decreases due to intensity fluctuations
Solution Approach 1:
The patent segments the detection function from the processing function by using separate detection laser light and processing laser light. This allows independent optimization of each function - the detection laser provides stable intensity for accurate detection, while the processing laser handles material processing, eliminating the trade-off between system complexity and detection accuracy.
Solution Approach 2:
The patent introduces a dedicated detection laser light source that can be simpler and more stable than the high-power processing laser. By using a separate, lower-cost detection laser optimized solely for detection purposes, the system achieves high detection accuracy without the complexity and instability of using the processing laser for both purposes.
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 device effectively detects optical fiber disconnection and other defects with high reliability, reducing the likelihood of erroneous detection and allowing for timely maintenance to maintain processing quality.
Implementation Method 1
an optical fiber that transmits second partial light of the detection laser light and processing laser light
Implementation Method 2
an optical fiber that transmits second partial light of the detection laser light and processing laser light and is provided with a mode stripper unit in the vicinity of an input end and another mode stripper unit in the vicinity of an output end
Implementation Method 3
multiple photoreceivers to measure light intensities
Implementation Method 4
a condensing lens that condenses the second partial light and the processing laser light to the input end of the optical fiber
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A failure detection device (1) includes a machining laser light source (10) that emits machining laser light, a detection laser light source (20) that emits detection laser light, an optical fiber (70) that is provided with mode stripper units (78) in the vicinity of input and output ends, a laser head (80), a condensing lens (36) that condenses the machining laser light to the input end of the optical fiber, second to fifth light detectors (110, 120, 130, 140), and a determination unit (50) that determines, based on the relative ratio of each of light intensities measured by the second to fifth light detectors and a temporal change in these light intensities, whether or not there is a defect in any of the optical fiber, the condensing lens, the laser head, and a machining target machining state.