
Proceedings Paper
On-machine laser triangulation sensor for precise surface displacement measurement of various material typesFormat | Member Price | Non-Member Price |
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Paper Abstract
The paper presents a custom-designed laser triangulation based metrology system, which enables high precision surface
displacement measurement of various material types with a single sensor configuration. Laser structuring applications
require material surface alignment relative to the laser focus position where fabrication conditions are optimal. The
measurement system utilizes a high-quality UV wavelength laser beam (primarily used for structuring purposes) with
automatic control of its intensity. The laser source operates in a continuous wave (CW) mode during the measurement
process, whereas the UV wavelength enables measurement of transparent materials. Robust displacement measurement
of various material types was solved by introducing a new approach of structured light projection and its centroid
detection. A high resolution 2D galvanometric scanning system is used for dynamic symmetrical pattern projection,
which is proven to reduce the effects of material surface related errors and speckle noise. Furthermore, a “double curve
fitting” (DCF) centroid detection algorithm, where Gaussian curves are fitted to radial cross sections of the acquired
pattern, and an ellipse is fitted to their peak positions, was introduced. The method includes subsurface scattering
compensation, which proves crucial for translucent material measurement, where incident light penetrates into the
material surface and causes uneven light intensity distribution of the acquired pattern. Experimental results have shown
that the metrology system is robust to laser intensity variation and material type, with measurement bias lower than 50
μm and standard deviation lower than ±6.3 μm for all materials. The developed probe has been integrated into
commercial LPKF laser structuring systems.
Paper Details
Date Published: 6 September 2013
PDF: 10 pages
Proc. SPIE 8839, Dimensional Optical Metrology and Inspection for Practical Applications II, 88390M (6 September 2013); doi: 10.1117/12.2022838
Published in SPIE Proceedings Vol. 8839:
Dimensional Optical Metrology and Inspection for Practical Applications II
Kevin G. Harding; Peisen S. Huang; Toru Yoshizawa, Editor(s)
PDF: 10 pages
Proc. SPIE 8839, Dimensional Optical Metrology and Inspection for Practical Applications II, 88390M (6 September 2013); doi: 10.1117/12.2022838
Show Author Affiliations
Klemen Žbontar, LPKF Laser and Elektronika d.o.o. (Slovenia)
Boštjan Podobnik, LPKF Laser and Elektronika d.o.o. (Slovenia)
Boštjan Podobnik, LPKF Laser and Elektronika d.o.o. (Slovenia)
Franc Povše, LPKF Laser and Elektronika d.o.o. (Slovenia)
Matjaž Mihelj, Univ. of Ljubljana (Slovenia)
Matjaž Mihelj, Univ. of Ljubljana (Slovenia)
Published in SPIE Proceedings Vol. 8839:
Dimensional Optical Metrology and Inspection for Practical Applications II
Kevin G. Harding; Peisen S. Huang; Toru Yoshizawa, Editor(s)
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