Laser Scanning Polygon Mirror With Real-Time Irradiated Facet Tracking
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Solution Overview
Problem
Laser processing apparatuses face challenges in accurately monitoring and adjusting the position of a laser beam on a polygon mirror's reflecting facets due to manufacturing errors, leading to inconsistent beam application and potential processing inaccuracies.
Innovation Solution
Incorporating an irradiated facet specifying unit with a reference facet detecting system that uses a light emitting and detecting unit to identify the current reflecting facet being irradiated, allowing for real-time monitoring and position adjustment of the laser beam on the polygon mirror.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a polygon mirror is used to scan the laser beam at high speed, then laser beam processing efficiency is improved, but manufacturing errors cause variations in reflecting facet angles leading to inaccurate beam positioning
Solution Approach 1:
The patent implements a feedback mechanism by detecting the rotation angle of the polygon mirror and using this information to calculate and correct the position where the laser beam is applied to each reflecting facet. The correction amount is determined based on the detected rotation angle, ensuring accurate beam positioning despite manufacturing variations in facet angles.
Solution Approach 2:
The patent changes the parameter of beam position correction by dynamically adjusting the correction amount based on the rotation angle of the polygon mirror. Instead of using fixed correction values, the system adapts the correction parameter in real-time to compensate for angle variations in the reflecting facets.
2Productivity
If the laser beam is scanned repeatedly at high speed, then meltage resolidification is prevented, but real-time monitoring of irradiated facets becomes necessary to maintain accuracy
Solution Approach 1:
The patent makes the optical system multi-functional by enabling it to perform both laser beam scanning and rotation angle detection functions. The same optical path is used for both the laser beam and the detection beam, allowing the system to monitor facet irradiation while maintaining high-speed processing capability.
Solution Approach 2:
The patent introduces a detection beam as an intermediary to monitor the irradiation status of reflecting facets. This detection beam serves as a mediator between the laser beam system and the control system, providing real-time information about which facets are being irradiated without interfering with the main processing function.
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 precise control of the laser beam's position on the workpiece, preventing unintended irradiation and improving processing accuracy by correcting for angle variations in the polygon mirror's facets, thus enhancing the efficiency and reliability of laser processing operations.
Implementation Method 1
a light emitting unit for emitting light to be applied to the reflecting facets
Implementation Method 2
a light detecting unit for detecting the light beam reflected by the reflecting facets
Implementation Method 3
a laser oscillator for emitting a laser beam
Implementation Method 4
When the laser beam applying unit applies a laser beam that is absorbable by a workpiece to the workpiece, the laser beam ablates the workpiece
Data Source
AI summary
A laser processing apparatus includes a holding table for holding a workpiece thereon, a laser oscillator for emitting a laser beam, a polygon mirror having a plurality of reflecting facets for scanning the laser beam emitted by the laser oscillator, a beam condenser for converging the laser beam scanned by the polygon mirror and applying the converged laser beam to the workpiece, and an irradiated facet specifying unit for specifying an irradiated facet of the polygon mirror to which the laser beam is applied among the reflecting facets.