Focus-Shifting Laser Marking Optics for Variable Topographies
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Solution Overview
Problem
Existing laser marking devices are not suitable for industrial use due to the complexity of integrating and controlling focus shift optics, which are prone to errors and affected by temperature fluctuations, making them inefficient for marking objects with varying topographies.
Innovation Solution
A laser marking device with a focus shifting optics system comprising three focusing elements, where at least one of the outer elements is adjustable, allowing for axial focus position changes without significant lateral beam diameter changes, improving industrial applicability by simplifying adjustments and reducing susceptibility to errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If liquid lenses are used as focus-shift optics to eliminate mechanical displacement, then the need for moving the entire optical structure is eliminated, but integration and control become very complex and temperature fluctuations cause unwanted changes in focus position and beam diameter
Solution Approach 1:
The optical system is segmented into multiple discrete focusing elements (at least three) arranged along the beam propagation direction, with at least one being adjustable. This segmentation replaces the integrated liquid lens with separate, controllable components that can be individually adjusted to achieve focus shifting without the complexity of liquid lens control systems.
Solution Approach 2:
The patent introduces dynamic adjustability of at least one focusing element along the optical axis, enabling real-time focus position changes. This dynamic adjustment mechanism provides operational flexibility similar to liquid lenses but with simpler, more reliable mechanical or motorized positioning that is less sensitive to environmental factors like temperature.
2Adaptability or versatility
If the entire optical setup is moved to adjust focus position for objects at different axial distances, then focus position can be adjusted, but the process involves considerable effort and is prone to misalignments
Solution Approach 1:
Instead of moving the entire optical setup as one rigid unit, the system is divided into fixed and adjustable components. The at least one adjustable focusing element can be independently positioned along the optical axis while other components remain stationary, enabling focus adjustment without disturbing the alignment of the complete optical path.
Solution Approach 2:
The adjustment function is extracted from the entire optical setup and localized to a specific focusing element. This allows focus position changes to be achieved by moving only the necessary component rather than the whole system, reducing the risk of misalignment and simplifying the adjustment process.
3Adaptability or versatility
If focus shift optics are used to change axial focus position, then marking of objects with varying topographies becomes possible, but temperature fluctuations lead to unwanted changes in focus position and beam diameter that are difficult to compensate
Solution Approach 1:
The system employs dynamic adjustability of focusing elements that can be actively controlled to compensate for temperature-induced drift. The at least one adjustable focusing element can be repositioned in real-time to maintain accurate focus position despite environmental changes, providing stable and reliable marking performance.
Solution Approach 2:
The patent utilizes changes in the positional parameter of the focusing element along the optical axis to achieve focus shifting. By controlling the position of at least one focusing element, the system can adjust the focal point's axial location to accommodate varying object topographies while maintaining beam quality and focus stability.
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
Enables consistent high-quality marking on objects with varying topographies by adjusting the focus position without altering the beam diameter, enhancing the device's industrial applicability and reducing errors, and allowing for a more compact design.
Implementation Method 1
the first focusing element faces the laser beam source and has a positive refractive power
Implementation Method 2
the second focusing element is arranged between the first focusing element and the third focusing element and has a negative refractive power
Implementation Method 3
the third focusing element faces the planar field lens and has a positive refractive power
Implementation Method 4
a planar field lens for focusing the laser beam onto the object to be marked
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a laser marking device for marking an object, comprising a laser beam source (7) for generating a laser beam and a deflection optic (8) for focusing the laser beam onto the object to be marked. The deflection optic (8) particularly includes a focus-shifting optic (14) with at least three focusing elements (3, 4, 5) arranged one behind the other along the direction of propagation of the laser beam. The first focusing element (3) is adjustable along the optical axis relative to the second focusing element (4) and the third focusing element (5), as well as relative to the laser beam source (7), and/or the third focusing element (5) is adjustable along the optical axis relative to the second focusing element (4) and the first focusing element (3), as well as relative to the laser beam source (7). The invention also relates to a method for marking an object using the laser marking device (6) according to the invention.