Laser Head Optical Path Difference Unit for Chromatic Aberration
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Solution Overview
Problem
Conventional laser processing apparatuses face challenges in simultaneously illuminating workpieces with infrared and visible laser light due to significant differences in condensing positions caused by chromatic aberration, making it difficult to maintain precise processing.
Innovation Solution
Incorporating an optical path difference generation unit within the laser head to adjust the optical path lengths of laser lights with different wavelengths, ensuring they converge at the same position on the workpiece, using a configuration that includes a polarization beam combiner and prisms to align and adjust the optical axes of the laser lights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser lights with different wavelengths are simultaneously illuminated to workpiece, then laser processing speed and light absorptance are improved, but condensing position deviation increases due to chromatic aberration
Solution Approach 1:
The patent applies preliminary anti-action by introducing an optical path difference generation unit that pre-compensates for chromatic aberration. The unit creates an optical path length difference between different wavelength laser lights before they reach the condensing optical system, specifically making the optical path of shorter wavelength light longer than that of longer wavelength light. This preliminary adjustment counteracts the chromatic aberration that would otherwise cause condensing position deviation, enabling simultaneous illumination of multiple wavelengths while maintaining precise condensing positions on the workpiece
2Device complexity
If conventional condensing optical system is used, then device complexity is reduced, but condensing position deviation between different wavelengths cannot be suppressed
Solution Approach 1:
The patent introduces an optical path difference generation unit as an intermediary component between the laser light source and the condensing optical system. This intermediary unit, which may include optical elements such as prisms or lenses with different optical path lengths for different wavelengths, mediates the interaction between multi-wavelength laser lights and the condensing system. It selectively adjusts the optical path lengths to compensate for chromatic aberration while maintaining relative simplicity of the overall system structure
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 reduces the difference in condensing positions for laser lights of varying wavelengths, allowing for precise and efficient simultaneous processing without widening the illumination spot or affecting processing quality.
Implementation Method 1
a phenomenon that a condensing position is also different when a wavelength of incident light is different occurs. This is called chromatic aberration of the condensing optical system.
Implementation Method 2
the optical path difference generation unit is configured to make an optical path length of the first laser light inside the housing longer than an optical path length of the second laser light
Data Source
AI summary
A laser processing apparatus includes first and second laser oscillators that emit first and second laser lights (LB1), (LB2) having wavelengths different from each other, an optical fiber that guides first and second laser lights (LB1), (LB2), and laser head (50) configured to condense first and second laser lights (LB1), (LB2), respectively, at predetermined positions of a workpiece. Laser head (50) includes optical path difference generation unit (70) provided inside second housing (51). Optical path difference generation unit (70) is configured to make an optical path length of first laser light (LB1) inside second housing (51) longer than an optical path length of second laser light (LB2).