Laser Distance Measurement Optics for Accurate Vapor Capillary Depth
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Solution Overview
Problem
Current distance measurement techniques in laser processing systems, such as those using mirror optics or F-Theta lenses, face challenges in accurately measuring the depth of vapor capillaries due to aberrations and high precision requirements, especially when the measuring beam is deflected from the optical axis, leading to inaccurate weld depth determination.
Innovation Solution
A distance measurement device for laser processing systems that includes collimating optics, deflection optics with transmissive optical elements that can be displaced relative to the optical axis to deflect the collimated measuring beam without affecting its divergence, and focusing optics to compensate for imaging errors, ensuring precise positioning and measurement of vapor capillary depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mirror optics (galvo scanners) are used for beam deflection, then the measuring beam can be positioned on the vapor capillary, but small angular changes cause large positional changes and aberrations increase beam diameter
Solution Approach 1:
The patent replaces mirror optics (mechanical deflection system) with a transmissive optical element that can be displaced along the optical axis. This substitution eliminates the angular-to-positional amplification effect of mirrors and the associated aberrations, providing more precise beam positioning while maintaining positioning capability.
Solution Approach 2:
The patent changes the deflection mechanism from angular adjustment of mirrors to axial displacement of a transmissive optical element. This parameter change transforms the control variable from angle to position, directly affecting beam location without introducing aberrations that increase beam diameter.
2Measurement precision
If F-Theta lenses are used for focusing, then the measuring beam maintains constant diameter during deflection, but these lenses are expensive and optimized for only one wavelength
Solution Approach 1:
The patent makes the transmissive optical element adjustable along the optical axis, enabling a single optical component to serve multiple functions: beam deflection, focusing, and aberration compensation. This eliminates the need for specialized F-Theta lenses optimized for specific wavelengths, providing wavelength independence and reducing system complexity.
Solution Approach 2:
The patent combines the functions of beam deflection and focusing into a single transmissive optical element by displacing it along the optical axis. This merging eliminates the need for separate F-Theta lenses and other specialized optics, reducing system complexity and cost while maintaining beam diameter consistency.
3Ease of operation
If the measuring beam is deflected from the optical axis, then lateral positioning is achieved, but aberrations occur that increase beam diameter in the focal area
Solution Approach 1:
The patent replaces angular deflection of mirrors with axial displacement of a transmissive optical element. This substitution maintains lateral positioning capability while avoiding the aberrations that occur when beams pass through focusing optics at angles, thereby preserving beam focus precision.
Solution Approach 2:
The patent changes the control parameter from deflection angle to axial position of the transmissive element. This parameter change enables lateral beam positioning without introducing angular deviations that cause aberrations in the focal area, maintaining both positioning capability and focus precision.
4Measurement precision
If high precision drives are used for lateral displacement of optical waveguide exit surface, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent extracts the high precision drive requirement from the lateral displacement mechanism by changing the deflection approach. Instead of requiring high precision lateral movement, the system uses axial displacement of a transmissive optical element, which can be achieved with simpler, less expensive mechanisms while maintaining measurement precision.
Solution Approach 2:
The patent substitutes complex lateral displacement mechanisms with a simpler axial displacement mechanism for the transmissive optical element. This substitution reduces drive system complexity and cost while maintaining the ability to achieve precise focus position adjustment through the optical lever effect.
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 solution allows for high-precision distance measurements, including depth profiles of vapor capillaries and topography, by maintaining the measuring beam's collimated state during deflection, reducing aberrations and improving positioning accuracy, thus enabling accurate weld depth determination without increasing the beam diameter at the workpiece surface.
Implementation Method 1
a collimator optic that defines an optical axis (201) and is configured to collimate an optical measuring beam
Implementation Method 2
a deflection optic, wherein the deflection optic comprises at least one transmissive optical element that is displaceable with respect to the optical axis in order to deflect the collimated optical measuring beam from the optical axis
Implementation Method 3
a focusing optic, which is configured to focus the deflected optical beam onto a workpiece
Data Source
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AI summary
The invention relates to a device (200) for distance measurement for a laser processing system (100), comprising a collimator optics configured to collimate an optical measuring beam, a deflecting optics (220) which defines an optical axis (201), the deflecting optics (220) comprising at least one transmissive optical element (222, 224) which is movable relative to the optical axis (201) in order to deflect the collimated optical measuring beam (13) from the optical axis (201), and a focusing optics (230) which is configured in order to focus the deflected measuring beam (13') onto a workpiece (1).