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Optical measurement Systems for Industrial Inspection XIII 2023

作者： Belkner, Johannes Stauffenberg, Jaqueline Tenorio, Christian Görner Ortlepp, Ingo Manske, Eberhard Technische Universität Ilmenau Institute of Process Measurement and Sensor Technology Max-Planck-Ring 12 Ilmenau98693 Germany

ISBN: (数字)9781510664463

ISBN: (纸本)9781510664456

Direct laser writing is a popular method for mask-less lithography that already achieved commercial grade. However, it is still challenging to realize homogeneously exposed structures on 3D-shaped substrates. A common source of the variation in exposure is a changing distance of the substrate surface with the photoresist towards the plane of the narrowest waist of the exposure beam. To tackle this issue, we propose a differential confocal probe that employs a spatially modulated pinhole. This phase-modulated lock-in principle enables highly resolved depth sensing without ambiguity about the direction of the deviation from the focal plane. However, the modulation contrast must be high enough to achieve this, which is why the measuring beam passes the pinhole twice. This probe is integrated into the nanopositioning and nanomeasuring machine via a position-based controller. We demonstrate the capability to follow 10◦ inclined substrates. © 2023 SPIE.

关键词： Confocal microscopy

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Long-term wavelength stabilisation of widely modulated lasers 13

Long-term wavelength stabilisation of widely modulated laser...

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Optical measurement Systems for Industrial Inspection XIII 2023

作者： Wiseman, Kieran B. Kissinger, Thomas Tatam, Ralph P. Centre for Engineering Photonics Cranfield University United Kingdom Institute of Process Measurement and Sensor Technology Technical University of Ilmenau Germany

ISBN: (数字)9781510664463

ISBN: (纸本)9781510664456

In this paper, we present a novel technique for stabilisation of widely wavelength modulated lasers (>100pm) over long time scales, where modulation depths exceed the spectral width of standard reference features, such as gas absorption lines, by over an order of magnitude. The technique operates by controlling the temporal separation between successive appearances of a gas absorption line on the up and down sweeps of a sinusoidal laser wavelength modulation waveform. The influence of the signal distortions introduced by the laser intensity modulation that are associated with laser diode injection current modulation are also addressed. The technique is applied to a range-resolved interferometric system interrogating a Mach-Zehnder interferometer operating in thermally stable conditions, using an absorption feature from a fibre-coupled gas cell as a reference. Proof-of-principle measurement results achieved using this technique are presented, demonstrating a notional fractional stability of 3.9×10−7 without further correction. © 2023 SPIE.

关键词： Stabilization

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Construction of a Time-Domain Full-Field OCT for non-contact volumetric layer thickness measurement 13

Construction of a Time-Domain Full-Field OCT for non-contact...

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Optical measurement Systems for Industrial Inspection XIII 2023

作者： Bulun, Georgis Lotz, Marvin Keksel, Andrej Stelzer, Gerhard Seewig, Jörg Institute for Measurement and Sensor Technology MTS Rheinland-Pfälzisch Technische Universität Kaiserslautern-Landau Kaiserslautern67663 Germany

ISBN: (数字)9781510664463

ISBN: (纸本)9781510664456

In this paper the design of a Time-Domain Full-Field OCT (TD-FF-OCT) setup for non-contact volumetric layer thickness measurement is presented and quantified in terms of achievable accuracy and performance. The capabilities of the instrument regarding its measuring accuracy are verified using foil thickness standards of different strength. Afterwards, a technical application of measuring a thin and rough varnish coated PET foil (foil thickness tfoil ≈ 150 µm, rough varnish layer thickness tvarnish ≈ 10 µm) is carried out. Since the device is designed to conduct areal measurements, the thickness can be accurately determined over several measurement points. The results are compared with results achieved by applying an alternative but destructive and more time-consuming measuring method (evaluation of microscopic images of respective foil slices produced by using a microtome). Finally, the achievements are summarized and identified optimization potential is highlighted. © 2023 SPIE.

关键词： Thickness measurement

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Designing stacked multi-wedge acoustic black holes using parameter variations 14

Designing stacked multi-wedge acoustic black holes using par...

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14th International Conference on Recent Advances in Structural Dynamics, RASD 2024

作者： Käfer, Max Dohnal, Fadi Research Center for Microtechnology Vorarlberg University of Applied Sciences Dornbirn Austria Institute of Measurement and Sensor Technology UMIT TIROL - Private University for Health Sciences and Health Technology Hall in Tirol Austria

Progressive industrialization is causing noise and vibration levels to rise. The negative impact on humans and the environment calls for protective measures to mitigate the disturbing sound and vibrations. Recent developments of noise absorbing materials have included acoustic metamaterials and acoustic black holes (ABH) into the focus of attention. It was shown analytically that no sound energy can escape from the ABH if the thickness of a tapered end goes to zero and the ABH is infinitely long. The wedge-shaped ABH serves here as a basis for further research and studies on matching focusing on specific frequency ranges. The combination of the CAD-software SOLIDWORKS, the FE-software COMSOL Multiphysics and Matlab enables a robust procedure to optimize the ABH design for specific, even low, frequency ranges. Therefore eigenfrequency, time domain and energy studies have been calculated. Combining the results is showing how the ABH performs at its eigenfrequencies. As a base structure, a simple beam was added to the ABH. If the beam stays at rest and the ABH is oscillating, its performance is positive meaning that the vibrational energy is concentrated at the tip of the ABH. The main focus here is the tuning of the ABH with parametric studies using parameter variations to the frequency range of interest. The resulting eigenfrequency curves are not only showing the optimal design parameters, but also the performance of the ABH at its frequency ranges. Furthermore a case study with a pipe system was carried out of an adapted ABH, underlining its performance. © 2024 institute of Physics Publishing. All rights reserved.

关键词： MATLAB

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CENTRE OF GRAVITY MEASURING DEVICE 24

CENTRE OF GRAVITY MEASURING DEVICE

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24th IMEKO TC3 Conference on measurement of Force, Mass and Torque 2022, Together with the 14th TC5 Conference on the measurement of Hardness, the 6th TC16 Conference on Pressure and Vacuum measurement, and the 5th TC22 Conference on Vibration measurement

作者： Pabst, M. Fröhlich, T. Technical University of Ilmenau Department of Mechanical Engineering Institute of Process Measurement and Sensor Technology Process Measurement Technology Group Ilmenau Germany

ISBN: (纸本)9781713870203

This paper describes a new method to measure the height of the centre of gravity of high-sensitive mass artefacts. A measuring device is presented and tested with mass samples of various shapes and densities. The results of the measurements are compared to the geometrical estimated heights of the centre of gravity and further developments of the new instrument are presented. © 2023 *** All Rights Reserved.

关键词： Comparators (optical)

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A 4 Bit Segmented Current-Steering Harmonic-Cancelling Digital-to-Analog Converter for High Frequency Sine-Wave Synthesis

A 4 Bit Segmented Current-Steering Harmonic-Cancelling Digit...

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IEEE Asia-Pacific Conference on Circuits and Systems

作者： Maximilian Scherzer Mario Auer Institute of Electrical Measurement and Sensor Systems Graz University of Technology

ISBN: (数字)9798350378771

ISBN: (纸本)9798350378788

Sinusoidal signal generators are critical in various integrated circuit systems, such as mixed-signal BIST applications, RF communication systems, and electrochemical impedance spectroscopy. Digital-to-analog converters, which only need to generate a sinusoidal signal, can be realized using digital harmonic-cancelling sine wave synthesizers (DHSS). The sine wave is obtained by adding weighted and shifted square waves, resulting in a staircase approximation of the sinusoid. However, due to mismatch, the weights have some variation, resulting in decreased performance. Dynamic element matching (DEM) techniques are possible, but existing implementations require a large number of unit elements. This paper presents a segmented harmonic-cancelling digital-to-analog converter (HC-DAC) that achieves comparable performance in terms of signal quality, but with a greatly decreased number of unit elements, thereby lowering the circuit complexity. Implemented in a 180 nm CMOS technology, the 4-bit segmented HC-DAC achieves an SDR of 77 dB at 2 MHz with a power consumption of $254 \mu \mathrm{~W}$ and minimal area usage. Simulation results validate the effectiveness of the proposed design, demonstrating significant performance improvements over existing sine wave synthesizers.

关键词： Integrated circuits Power demand Synthesizers Digital-analog conversion Simulation Layout DH-HEMTs Signal generators Complexity theory High frequency

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Surface data imputation with stochastic processes

arXiv

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arXiv 2024年

作者： Jawaid, Arsalan Schmidt, Samuel Seewig, Jorg Institute for Measurement and Sensor Technology University of Kaiserslautern-Landau Germany

Spurious measurements in surface data are common in technical surfaces. Excluding or ignoring these spurious points may lead to incorrect surface characterization if these points inherit features of the surface. Therefore, data imputation must be applied to ensure that the estimated data points at spurious measurements do not strongly deviate from the true surface and its characteristics. Traditional surface data imputation methods rely on simple assumptions and ignore existing knowledge of the surface, yielding in suboptimal estimates. In this paper, we propose using stochastic processes for data imputation. This approach, which originates from surface simulation, allows for the straightforward integration of a priori knowledge. We employ Gaussian processes for surface data imputation with artificially generated missing features. Both the surfaces and the missing features are generated artificially. Our results demonstrate that the proposed method fills the missing values and interpolates data points with better alignment to the measured surface compared to traditional approaches, particularly when surface features are missing. © 2024, CC BY.

关键词： Data assimilation

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Towards an Enhanced Metrology Analysis Procedure for Assessing Position Accuracy of Edge-Emitting Lasers to Photonic Integrated Circuits

Towards an Enhanced Metrology Analysis Procedure for Assessi...

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2024 IEEE Photonics Conference, IPC 2024

作者： Hinum-Wagner, Jakob Wilhelm Kraft, Jochen Sidorov, Victor Hoermann, Samuel Feigl, Gandolf Bergmann, Alexander Ams Osram Group Tobelbaderstraße 30 Premstaetten8054 Austria Graz University of Technology Institute of Electrical Measurement and Sensor Systems Inffeldgasse 33 Graz8010 Austria

ISBN: (纸本)9798350361957

Advanced photonic integrated systems require precise light source coupling, especially with edge-emitting lasers. This paper discusses how passive 2D alignment achieves below-micron accuracy. It introduces a metrology procedure for consistent analysis of the positioning process in manufacturing, ensuring optimal performance and reliable failure analysis. © 2024 IEEE.

关键词： Photonic integrated circuits

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DC measurement in HVAC-Systems: Status Quo and Recent Developments 58

DC Measurement in HVAC-Systems: Status Quo and Recent Develo...

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58th International Universities Power Engineering Conference, UPEC 2023

作者： Schachinger, Philipp Albert, Dennis Frohlich, Alexander Renner, Herwig Mandl, Johannes Trampitsch, Philipp Klambauer, Reinhard Bergmann, Alexander Schoffer, Werner Institute of Electrical Power Systems Graz University of Technology Graz Austria Institute of Electrical Measurement and Sensor Systems Graz University of Technology Graz Austria Artemes GmbH Eibiswald Austria

ISBN: (纸本)9798350316834

The measurement of small direct currents in presence of high AC currents on high voltage potential is a challenging task. Inductive current transducers (CT) are not able to measure DC and other non-conventional CTs are also not designed for DC. Therefore, DC measurements are done in transformer neutral points on ground potential. In this work, the state of the art on DC measurements in the high-voltage transmission grid is given, including the measurement in the transformer neutral point, the indirect measurement with the differential magnetometer method, and the indirect method of measuring a compensating current. In addition an optical current measurement system under development is presented. © 2023 IEEE.

关键词： DC transformers

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Experiments of Time-Periodic Control During Run-Up of a Flexible Rotor 7

Experiments of Time-Periodic Control During Run-Up of a Flex...

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7th International Conference on Material Strength and Applied Mechanics, MSAM 2024

作者： Fasih, Muhammad Saad Van Baren, Johannes Dohnal, Fadi Research Center for Microtechnology Vorarlberg University of Applied Sciences Austria Fontys University of Applied Sciences Netherlands Institute of Measurement and Sensor Technology UMIT Tirol-Private University for Health Sciences and Health Technology Austria

ISBN: (纸本)9781643685472

Flexible rotors must pass through at least one critical speed before reaching its nominal or working speed. During passage through this resonance, transient vibrations are introduced in the rotor. For a better performance of the machinery, these vibrations must be kept below a certain threshold to keep a small clearance between the rotor and the stator. Modal coupling by periodic control is a modern approach which is capable of transferring kinetic energy between two selected modes. By introducing a time-periodic variation of the bearing characteristics, a modal energy transfer is induced in a flexible rotor during run-up and run-down. This concept reduces the main resonance peak during passage through resonance compared to the nominal run-up. By the application of this technique, we were able to reduce the maximum amplitude response during the run-up to 25.4 percent and during the run-down to 27.1 percent. © The Author(s), 2024.

关键词： Kinetic energy

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