Laser Head Optics for Real-Time Numerical Aperture Detection
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Solution Overview
Problem
Conventional laser processing apparatuses face challenges in detecting the numerical aperture of laser light incident on an optical fiber in real time, leading to fluctuations in beam quality and machining accuracy due to temperature changes and output variations.
Innovation Solution
The apparatus includes a laser head with first and second optical components, each with a coating film, and light receivers to detect changes in the numerical aperture by analyzing reflected light signals, allowing for real-time monitoring and adjustment of the optical components to maintain desired beam quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thermocouple is used to detect temperature distribution of the condensing lens, then the refractive index distribution can be indirectly obtained, but it is difficult to detect the numerical aperture change in real time and in a short time
Solution Approach 1:
The patent replaces the mechanical thermocouple-based temperature measurement system with an optical detection system using light receivers and coating films. This substitution enables direct optical measurement of the numerical aperture through reflected light intensity ratios, eliminating the time-consuming indirect temperature measurement process and achieving real-time detection.
Solution Approach 2:
The patent introduces coating films with specific reflectances as intermediaries between the laser light and the light receivers. These coating films enable the extraction of numerical aperture information from the reflected light intensity ratio, serving as a mediator that translates optical parameters into detectable signals for real-time measurement.
2Power
If the output of the laser light is greatly changed, then the power output can be adjusted, but the divergence angle of the laser light changes and the beam quality deteriorates
Solution Approach 1:
The patent implements a feedback control system where light receivers continuously monitor the reflected light intensity ratio, which corresponds to the numerical aperture. When the divergence angle changes due to output power adjustments, the system detects this change and can trigger corrections to restore the optimal beam quality, ensuring stable machining accuracy across different power levels.
3Duration of action of stationary object
If the optical axis of the laser light fluctuates, then the laser oscillator continues to operate, but the numerical aperture of the laser beam incident on the optical fiber fluctuates and machining accuracy is impaired
Solution Approach 1:
The patent employs a feedback mechanism where the light receivers continuously monitor the reflected light intensity ratio during operation. When optical axis fluctuations cause numerical aperture changes that affect machining accuracy, the system detects these variations in real-time and can initiate corrective actions to maintain consistent beam quality and machining precision throughout continuous operation.
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 rapid detection and correction of numerical aperture changes, ensuring consistent beam quality and improved machining accuracy by using reflected light signals to adjust the optical components in real time.
Implementation Method 1
the first optical component is provided with a first coating film having a predetermined reflectance on at least one of light receiving surfaces of the laser light
Implementation Method 2
the second optical component is provided with a second coating film on at least one of light receiving surfaces of the laser light, the first light receiver receives the laser light reflected by the first coating film
Data Source
AI summary
A laser processing apparatus includes at least a laser oscillator, optical fiber (30), and laser head (40). Laser head (40) includes at least first and second shield glasses (45) and (47) and first and second light receivers (51) and (52) inside second housing (41). In first and second shield glasses (45) and (47), first and second coating films (46) and (48) are respectively provided on light receiving surfaces of laser light (LB). First light receiver (51) receives laser light (LB) reflected by first coating film (46) and outputs a first light receiving signal, and second light receiver (52) receives laser light (LB) reflected by peripheral portion (48b) of second coating film (48) and outputs a second light receiving signal.