Polygon Mirror Laser Scanning With Facet Position Compensation
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Solution Overview
Problem
The challenge of accurately scanning a laser beam using a polygon mirror is exacerbated by fabrication errors that cause reflective facets to be misaligned, leading to unintended application of the laser beam on the workpiece.
Innovation Solution
A laser processing apparatus and method that incorporate a position adjusting unit to correct the irradiated positions of the reflective facets based on measured positions, ensuring precise scanning despite angle variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a polygon mirror is used to scan the laser beam at high speed, then the processing efficiency is improved, but the manufacturing precision deteriorates due to fabrication errors causing misalignment of reflective facets
Solution Approach 1:
The system performs preliminary measurement of the actual positions of reflective facets on the polygon mirror before laser processing. The measuring unit captures position data of each reflective facet, and the controller stores this information for subsequent compensation during the laser scanning process, enabling pre-correction of fabrication errors
Solution Approach 2:
The system implements feedback by using the measured position data of reflective facets to dynamically adjust the laser beam irradiation positions. The controller compares the actual facet positions with the ideal positions and compensates for deviations in real-time during laser scanning, ensuring accurate positioning despite manufacturing variations
Solution Approach 3:
The system changes the operational parameters by adjusting the laser beam irradiation positions based on the measured facet positions. The controller modifies the timing and positioning parameters of laser application to account for the actual geometry of the polygon mirror, transforming the fixed manufacturing errors into correctable variable parameters
2Device complexity
If the reflective facets are not parallel to the central axis due to fabrication errors, then the device complexity is reduced (no additional adjustment mechanisms), but the manufacturing precision of laser beam application deteriorates
Solution Approach 1:
The system replaces complex mechanical adjustment mechanisms (such as adjustable mounts or alignment mechanisms) with a measurement and computational compensation approach. Instead of mechanically adjusting each reflective facet to be parallel to the central axis, the system measures the actual positions and uses software-based position correction to achieve accurate laser application
Solution Approach 2:
The system creates a digital copy or model of the actual polygon mirror geometry by measuring the positions of all reflective facets. This digital representation is stored in the controller and used to calculate the correct laser beam irradiation timing and positions, replacing the need for physical alignment adjustments
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 solution enables appropriate scanning of the laser beam even with misaligned reflective facets, enhancing processing efficiency and accuracy.
Implementation Method 1
a polygon mirror having a plurality of reflective facets and rotatable for scanning the laser beam
Implementation Method 2
a beam condenser for focusing the laser beam scanned by the polygon mirror
Implementation Method 3
The laser beam applying unit irradiates the workpiece with a laser beam that is absorbable by the workpiece, thereby processing the workpiece by way of ablation to divide the workpiece
Data Source
AI summary
A laser processing apparatus includes a laser oscillator for emitting a laser beam, a polygon mirror having a plurality of reflective facets and rotatable for scanning the laser beam, a beam condenser for focusing the laser beam scanned by the polygon mirror, a position adjusting unit for adjusting irradiated positions where the reflective facets are irradiated with the laser beam, and a measuring unit for measuring the positions of irradiated regions that are irradiated with the laser beam scanned by the polygon mirror, in which the position adjusting unit adjusts the irradiated positions where the reflective facets are irradiated with the laser beam with respect to the respective reflective facets on the basis of the positions of the irradiated regions measured by the measuring unit with respect to the respective reflective facets.