F-Theta Lens Layout for Diffraction-Limited Laser Scanning
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Solution Overview
Problem
Conventional f-theta lenses are inadequate for modern laser sources with diffraction-limited beam quality, failing to meet high imaging quality and position accuracy requirements in applications like hairpin welding for electric vehicles.
Innovation Solution
The f-theta lens is arranged in a divergent beam path to focus the laser beam into a focus plane located at a distance from its focal plane, optimizing imaging quality and scan field size by maintaining a specific ratio of distance to total focal length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional f-theta lenses are used for high-power laser sources, then the imaging quality is sufficient for multimode lasers, but the imaging quality becomes insufficient for fundamental mode lasers with diffraction-limited beam quality
Solution Approach 1:
The patent applies parameter changes by optimizing the f-theta lens design parameters including the ratio of distance from focal plane to total focal length (0.001 to 0.05), the f-number range (0.8 to 2.5), and the scan field angle (±5° to ±20°). These parameter optimizations enable the lens to achieve diffraction-limited imaging quality while maintaining compatibility with both fundamental mode and multimode laser sources across a wide range of applications
2Manufacturing precision
If the f-theta lens is placed in a collimated beam path, then the design is simpler, but the focus plane position accuracy and imaging quality deteriorate
Solution Approach 1:
The patent inverts the conventional approach by placing the f-theta lens in a divergent beam path instead of a collimated beam path. This inversion allows the lens to receive divergent beams from the laser source and correctly focus them onto the focus plane, achieving high position accuracy and imaging quality that would not be possible with conventional collimated beam configurations
3Manufacturing precision
If the focus plane is positioned at the focal plane of the f-theta lens, then the optical path is shorter, but the imaging quality and scan field performance deteriorate
Solution Approach 1:
The patent optimizes the distance parameter between the focal plane and focus plane within the specific range of 0.001 to 0.05 times the total focal length. This parameter optimization achieves the best compromise between optical path length and imaging quality, ensuring diffraction-limited performance across the entire scan field while maintaining a practical optical path length for various applications
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 achieves diffraction-limited imaging with a large scan field, suitable for both fundamental mode and multimode laser sources, enhancing performance in material processing applications.
Implementation Method 1
The f-theta lens is disposed in a divergent beam path of the optical arrangement in order to focus the laser beam into a focus plane
Implementation Method 2
The f-theta lens is disposed in a divergent beam path of the optical arrangement in order to focus the laser beam into a focus plane
Data Source
AI summary
An optical arrangement for a laser beam includes an f-theta lens. The f-theta lens is disposed in a divergent beam path of the optical arrangement in order to focus the laser beam into a focus plane. The focus plane is located at a distance from a focal plane of the f-theta lens.