Laser Processing Lens Positioning for Surface Irregularity
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Solution Overview
Problem
Conventional laser processing techniques face challenges in maintaining the precision of the laser beam converging point, especially at the end parts of objects with irregularities, leading to inefficiencies and deviations during processing.
Innovation Solution
A method and apparatus that utilize a first laser beam for processing and a second laser beam for measuring displacement, with a piezoelectric actuator to adjust the lens position, ensuring the converging point remains within the object by acquiring displacement and setting initial positions based on measured data, minimizing deviations and fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurement means is arranged in parallel with condenser lens to measure main surface height, then the main surface height can be measured, but the converging point of laser beam deviates in end parts of the object
Solution Approach 1:
The patent transitions from two-dimensional surface height measurement to three-dimensional spatial positioning by calculating the object's position relative to the laser beam entry point using the formula involving arcsin function. This dimensional transformation allows accurate positioning in the depth dimension (along the laser beam path) rather than only measuring surface height variations.
Solution Approach 2:
The patent introduces an intermediary calculation method that uses the measured main surface height combined with geometric relationships (entry point position, laser beam angle) to determine the actual processing position. This intermediary calculation bridges the gap between surface measurement and internal processing position, ensuring accurate converging point positioning.
2Measurement precision
If planarity measuring means is used to measure planarity before processing, then planarity can be accurately grasped, but the same part must be scanned twice which lowers processing efficiency
Solution Approach 1:
The patent combines the measurement function and processing function into a single integrated operation. By using the main surface height measurement taken during the processing scan itself (rather than a separate pre-measurement scan), the system merges what were previously two separate operations into one, thereby maintaining measurement accuracy while eliminating the time loss from redundant scanning.
Solution Approach 2:
The patent performs preliminary calculation of the processing position based on the measured main surface height data obtained during the scan. By pre-calculating the required laser beam entry point position and angle using the measured height information, the system prepares the processing parameters in advance, allowing immediate processing without waiting for separate measurement completion.
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 approach enables efficient laser processing by maintaining the converging point's precision within the object, reducing errors and increasing processing efficiency, especially at the end parts of objects with irregular shapes.
Implementation Method 1
a piezoelectric actuator which holds the lens holder such that the latter can freely advance and retract with respect to the object
Implementation Method 2
a condenser lens for converging the laser beam onto the object
Implementation Method 3
irradiating an object to be processed with a first laser beam while converging the first laser beam with a lens such that a converging point is positioned within the object, and forming a modified region within the object
Data Source
AI summary
A laser processing method having a displacement acquiring step of acquiring a displacement between a point on the cutting line and one end of the cutting line in the object while irradiating the object with a second laser beam, converged by a lens, for measuring the displacement of a main surface of the object; and a position setting step of setting an initial position for holding the lens with respect to the main surface of the object according to the acquired displacement, and holding the lens at thus set initial position.