Mirror Tilt Detection in Laser Beam Scanning
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Solution Overview
Problem
Conventional light beam scanning apparatuses fail to accurately detect mirror tilting, leading to vibration-induced machining errors and failures during high-speed operations in laser machining processes.
Innovation Solution
A light beam scanning apparatus equipped with a detector and processor that measures the tilt of a mirror relative to its rotation axis, allowing for feedback control to adjust the mirror's rotation angle and ensure accurate positioning, using detectors such as PSDs, interferometers, or electrostatic capacitance sensors to calculate and correct for tilt deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the mirror is rotated at high speed to achieve high-speed machining, then productivity is improved, but vibration is excited in the motor causing positioning accuracy deterioration
Solution Approach 1:
The patent employs a feedback mechanism where a detector continuously monitors the actual rotation angle of the mirror, and the control unit compares this with the commanded rotation angle to detect tilt components. The system then adjusts the commanded rotation angle to compensate for detected tilt, forming a closed-loop control that maintains positioning accuracy during high-speed operation
Solution Approach 2:
The patent replaces mechanical dynamic balance adjustment with an optical detection and computational compensation system. Instead of mechanically balancing the mirror assembly to suppress vibration, the system uses optical detectors to measure tilt and computational algorithms to compensate, substituting mechanical solutions with optical and information processing approaches
2Device complexity
If conventional detectors are used to detect mirror rotation angle, then device complexity is kept simple, but tilt detection capability is insufficient leading to machining failures
Solution Approach 1:
The patent segments the detection function into multiple independent detectors positioned at different locations on the mirror. Each detector measures the rotation angle from its specific position, and the control unit synthesizes these measurements to calculate tilt components, dividing the complex tilt detection task into simpler individual measurements
Solution Approach 2:
The patent transitions from one-dimensional rotation angle detection to two-dimensional tilt detection by adding detectors at different positions and using computational processing to extract tilt information from the spatial distribution of detection signals, adding a dimensional aspect to the detection capability
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 solution enhances the positioning accuracy and process accuracy of laser machining by detecting and compensating for mirror tilts, reducing the likelihood of machining failures and ensuring precise control of laser light irradiation on the workpiece.
Implementation Method 1
a mirror configured to reflect an incident light beam... detecting tilt of a detected region of the mirror with respect to a rotation angle of the mirror
Data Source
AI summary
A scanning apparatus for scanning a light beam includes a mirror configured to reflect an incident light beam, a motor configured to rotate the mirror to change a direction along which the light beam reflected by the mirror travels, and a detector configured to obtain a detection value corresponding to a tilt of a detected region of the mirror, with the detection value being changed in accordance with a rotation angle of the mirror. In addition, a processor is configured to obtain a tilt angle of the mirror based on the detection value obtained by the detector and the rotation angle of the mirror.