Non-Circular Laser Beam Shaping Optical System
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Solution Overview
Problem
Current optical systems fail to effectively deliver a non-circular laser beam with the desired intensity and image placement to a workpiece, particularly in high-power applications like welding and heat treatment, where a non-circular fiber core is used, as they often result in an incorrect image size and intensity distribution.
Innovation Solution
An optical system comprising a combination of five spaced lenses, including three upstream lenses to form a non-circular image in a beam waist and two downstream lenses, specifically an F-theta lens, to adjust the spot size and intensity to the desired level, ensuring the image coincides with the beam waist and is placed within the Rayleigh range for optimal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a non-circular fiber core is used to deliver laser light, then the beam shape matches the fiber core geometry, but the image of the core does not form at the desired location with the desired intensity
Solution Approach 1:
The optical system is divided into three distinct functional segments: upstream lenses (first and second) that collimate and condition the beam, a middle section with a third lens that begins focusing, and downstream lenses (fourth and fifth) that complete the imaging. This segmentation allows each group to be optimized for its specific function, enabling the non-circular beam shape to be preserved while achieving precise image formation at the focal plane with correct intensity distribution.
2Manufacturing precision
If the workpiece is placed in the focal plane to receive the image, then the image can be formed, but the beam intensity is not maximized at that location
Solution Approach 1:
The patent extends the optical path beyond the simple focal plane by adding downstream lenses (fourth and fifth) that continue the focusing process. This dimensional extension in the optical path allows the system to achieve both image formation at the focal plane and maximum intensity concentration at that same location, resolving the contradiction between image formation and intensity maximization.
3Device complexity
If standard optical components are used, then the system is simple, but the image of the non-circular core is distorted and does not match the desired shape
Solution Approach 1:
Each lens in the five-lens system is designed with specific local optical properties tailored to its position in the beam path. The upstream lenses have different focal lengths and optical characteristics than the downstream lenses, allowing each component to contribute specifically to preserving the non-circular beam shape while maintaining overall system functionality. This localized optimization ensures shape fidelity without requiring excessive complexity.
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 system successfully forms a non-circular image with the desired intensity at the focal plane, ensuring uniform processing and maximum intensity on the workpiece, effectively addressing the limitations of existing systems in high-power applications.
Implementation Method 1
An optical system is disclosed including a combination of five lenses spaced apart from one another along a light path and having respective optical characteristics which serve to place a non-circular image in a waist of a beam emitted by a non-circular core fiber and then adjust a spot size of the image to a desired one
Data Source
Figure 1A~1D
Figure 2~3
Figure 4~6
AI summary
An optical system for forming a final image of a non-circular light source on a workpiece with a desired non-circular cross-section and desired size B includes a plurality of spaced leases. The plurality of lenses are arranged with spaced upstream and downstream lenses which are configured to transmit the beam emitted by the light source. The optical system is configured with an F-theta lens spaced downstream from the downstream lens and converging the beam incident thereon so that the beam has a final waist. The F-theta and downstream lenses are spaced apart so that -, wherein F4 a positive focal length of the downstream lens, Fth is the negative focus of the F-theta lens, B is the desired size of the final image, and A is a size of a preliminary noncircular image of the source different from the desired size B.