Multi-Wavelength Laser Beam Scanning With Synchronized Focus Shift
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Solution Overview
Problem
Existing laser processing devices face challenges in superimposing laser beams of different wavelengths using a Galvano scanner due to chromatic aberration, which results in deviation of irradiation positions on the processing object, making it difficult to achieve desired laser processing results.
Innovation Solution
A laser processing device is designed with a combiner unit to superimpose laser beams of different wavelengths, a focus shifter unit to adjust the focal length, and a Galvano scanner unit to change the optical axis direction, with synchronization between focal length adjustment and optical axis direction change to minimize chromatic aberration effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a Galvano scanner is used to change the direction of the optical axis of the laser beam, then high-speed and high-accuracy beam direction control is achieved, but the optical path length from the mirror to the processing object changes causing focus deviation
Solution Approach 1:
The system employs dynamic focus adjustment by making the focal length of the fθ lens variable. As the Galvano scanner changes the beam direction and optical path length, the focal length is dynamically adjusted to compensate for focus deviation, ensuring the laser beam remains properly focused on the processing object surface throughout the scanning range.
2Power
If multiple laser beams with different wavelengths are superimposed to irradiate the processing object, then both copper absorption (blue laser) and sufficient output power (infrared laser) are achieved, but chromatic aberration causes deviation in irradiation positions making desired processing results difficult to obtain
Solution Approach 1:
The chromatic aberration corrector lens serves as a mediator that specifically corrects the wavelength-dependent deviation caused by the fθ lens. It ensures that multiple laser beams with different wavelengths (blue and infrared) that have been superimposed converge at the same irradiation position on the processing object, enabling both high power delivery and precise positioning.
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 configuration allows for accurate and precise irradiation of superimposed laser beams on the processing object, avoiding chromatic aberration-related deviations and ensuring desired processing results, such as effective welding of copper plates and terminals.
Implementation Method 1
a combiner unit configured to superimpose a plurality of laser beams having different wavelengths on the same optical axis
Implementation Method 2
a chromatic aberration is inevitably generated based on universal physical laws (because a refractive index of light depends on a wavelength of the light)
Implementation Method 3
The Galvano scanner includes a mirror that reflects the laser beam, and a servo motor or a stepping motor that rotates the mirror at a high speed and with high accuracy
Implementation Method 4
Copper well absorbs blue light, but an output of an existing blue laser beam source is not sufficiently large, so that a high-output infrared laser beam source is used together
Data Source
AI summary
A laser processing device 0 includes a combiner unit 3 configured to superimpose a plurality of laser beams L1 and L2 having different wavelengths on the same optical axis; a focus shifter unit 4 configured to adjust a focal length of the laser beams L1 and L2 superimposed by the combiner unit 3; and a Galvano scanner unit 5 located downstream of the focus shifter unit 4 and configured to change a direction of the optical axis of the laser beams L1 and L2 traveling toward a processing object, and the adjustment in the focal length performed by the focus shifter unit 4 is synchronized with the change in the direction of the optical axis performed by the Galvano scanner unit 5.