Laser Beam Spot Shape Correction via Spatial Light Modulator Phase Control
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Solution Overview
Problem
Existing laser beam spot shape correction methods are inefficient in identifying and correcting optical distortions in laser processing systems, leading to machine differences between processing apparatuses and requiring excessive man-hours for correction.
Innovation Solution
A method involving a spatial light modulator, concave mirror, and imaging unit to adjust the laser beam's phase pattern, allowing for real-time imaging and comparison of the beam's shape and intensity distribution with ideal standards, enabling precise correction of aberrations and reducing machine differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a concave mirror is used to grasp the spot shape by imaging reflected light, then the spot shape can be measured, but the position of optical distortion cannot be identified and excessive man-hours are required for correction
Solution Approach 1:
The optical system is segmented into multiple optical elements, and distortion measurement is performed for each element individually by positioning the concave mirror at different locations along the optical path. This allows identification of which specific optical element causes the distortion, eliminating the need for trial-and-error correction of the entire system.
Solution Approach 2:
The concave mirror serves as an intermediary measurement tool that is temporarily positioned at different locations in the optical path. By using this movable intermediary, the system can measure distortion at each optical element without permanently altering the optical system structure.
2Adaptability or versatility
If multiple optical elements are used in the laser processing apparatus, then functional requirements are met, but optical distortions occur causing machine differences between apparatuses
Solution Approach 1:
The invention measures and quantifies optical distortion parameters (such as wavefront error, focal point position, and beam shape parameters) for each optical element. By changing and controlling these parameters through precise measurement and compensation, the system maintains processing consistency across different apparatuses while preserving the necessary functional versatility of multiple optical elements.
3Manufacturing precision
If manual identification and correction of optical distortion is performed, then spot shape can be corrected, but the process requires excessive man-hours
Solution Approach 1:
The system performs self-diagnosis by automatically measuring optical distortion at each optical element using the concave mirror and imaging unit. The measurement results directly indicate which element requires adjustment, enabling the system to self-correct without extensive manual intervention, thus maintaining high precision while improving correction efficiency.
Solution Approach 2:
The invention implements a feedback mechanism where the measured distortion at each optical element is used to determine the necessary correction. The imaging unit provides real-time feedback on the spot shape, allowing for precise and rapid adjustment of individual optical elements to achieve the desired beam quality.
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 significantly reduces the time and effort required for laser beam spot shape correction, minimizing machine differences between processing apparatuses and improving processing consistency.
Implementation Method 1
positioning a concave mirror having a reflecting surface as a spherical surface at a position facing the condensing lens... irradiating the concave mirror with the laser beam condensed by the condensing lens... imaging reflected light reflected by the reflecting surface of the concave mirror
Implementation Method 2
a condensing lens configured to condense the laser beam emitted from the laser oscillator
Implementation Method 3
a condensing lens configured to condense the laser beam emitted from the laser oscillator
Implementation Method 4
a spatial light modulator disposed between the laser oscillator and the condensing lens... A phase pattern displayed on a display unit of the spatial light modulator is changed
Data Source
AI summary
A laser beam spot shape correcting method includes a laser beam irradiating step of irradiating a concave mirror with a laser beam, an imaging step of imaging reflected light by a beam profiler, an image forming step of forming an XZ plane image or a YZ plane image from an XY plane image imaged in the imaging step, and a comparing step of comparing the image formed in the image forming step with an XZ plane image or a YZ plane image of an ideal laser beam. A phase pattern displayed on a display unit of a spatial light modulator is changed such that the XZ plane image or the YZ plane image formed in the image forming step coincides with the XZ plane image or the YZ plane image of the ideal laser beam.