TY - JOUR A1 - Bochtler, Ulrich A1 - Hellmann, Ralf A1 - Kaloudis, Michael A1 - Amrhein, Frank A1 - Glaab, Johannes A1 - Kaloumenos, Mareiki A1 - Sauer, Michael A1 - Gockel, Tilo T1 - LUVLED - UV-Leistungslichtquelle auf Leuchtdiodenbasis JF - Elektor Sonderheft, LEDs 2 KW - Lumineszenzdiode Y1 - 2010 VL - 2011 IS - 2 SP - 57 EP - 63 PB - Elektor-Verlag CY - Aachen ER - TY - JOUR A1 - Schneider, Johannes A1 - Bochtler, Ulrich A1 - Hellmann, Ralf A1 - Kaloudis, Michael A1 - Gockel, Tilo T1 - LUVLED III – Optimierung eines Kühlkonzeptes zur Aktivluftkühlung eines Hochleistungs-UV-LED-Moduls JF - Zeitschrift ELEKTOR, Sonderheft LED-Special 4 – Leuchtdioden in Theorie und Praxis, 2012 KW - UV-LED Modul KW - Lumineszenzdiode Y1 - 2012 IS - 9 SP - 20 EP - 29 ER - TY - JOUR A1 - Fuchs, Christopher A1 - Schreck, Timo A1 - Kaloudis, Michael T1 - Metallographische Untersuchungen an Sn-8Zn-3Bi-Lötverbindungen JF - PLUS KW - Lötverbindung KW - Metallographie Y1 - 2011 VL - 13 IS - 10 SP - 2378 EP - 2384 ER - TY - JOUR A1 - Kefer, Stefan A1 - Sauer, Theresia A1 - Hessler, Steffen A1 - Kaloudis, Michael A1 - Hellmann, Ralf T1 - Microstructure-Based Fiber-to-Chip Coupling of Polymer Planar Bragg Gratings for Harsh Environment Applications JF - Sensors (Basel) N2 - This article proposes and demonstrates a robust microstructure-based fiber-to-chip coupling scheme for planar Bragg grating devices. A polymer planar Bragg grating substrate is manufactured and microstructured by means of a micromilling process, while the respective photonic structures are generated by employing a sophisticated single-writing UV-exposure method. A stripped standard single mode fiber is inserted into the microstructure, which is filled with a UV-curable adhesive, and aligned with the integrated waveguide. After curing, final sensor assembly and thermal treatment, the proposed coupling scheme is capable of withstanding pressures up to 10 bar, at room temperature, and pressures up to 7.5 bar at an elevated temperature of 120 °C. Additionally, the coupling scheme is exceedingly robust towards tensile forces, limited only by the tensile strength of the employed single mode fiber. Due to its outstanding robustness, the coupling scheme enables the application of planar Bragg grating devices in harsh environments. This fact is underlined by integrating a microstructure-coupled photonic device into the center of a commercial-grade carbon fiber-reinforced polymer specimen. After its integration, the polymer-based Bragg grating sensor still exhibits a reflection peak with a dynamic range of 24 dB, and can thus be employed for sensing purposes. KW - Bragg grating sensors KW - cyclic olefin copolymers KW - fiber-to-chip coupling KW - microstructures KW - micromilling Y1 - 2020 UR - https://www.mdpi.com/1424-8220/20/19/5452/htm U6 - https://doi.org/10.3390/s20195452 VL - 20 IS - 19 SP - 5452 EP - 5452 ER - TY - CHAP A1 - Kefer, Stefan A1 - Roth, Frederick A1 - Kaloudis, Michael A1 - Schmauss, Bernhard A1 - Hellmann, Ralf T1 - Monitoring of Composite Bicycle Components using Polymer Planar Bragg Gratings T2 - SMSI 2021 - Sensors and Instrumentation N2 - This study demonstrates mobile load monitoring of a composite bicycle component using an application- customized polymer planar Bragg grating sensor, evaluated by a mobile interrogation unit. After a referencing procedure, the mechanical load of a seat post is monitored while cycling through a test track. KW - Bragg Grating KW - Composites KW - Cyclic Olefin Copolymers KW - Micromilling KW - Load Monitoring KW - Bragg-Reflektor KW - Verbundwerkstoff KW - Fahrrad Y1 - 2021 UR - https://www.ama-science.org/proceedings/details/3992 SN - 978-3-9819376-4-0 U6 - https://doi.org/10.5162/SMSI2021/B9.2 SP - 161 EP - 162 PB - AMA Service GmbH CY - Wunstorf, Germany ER - TY - JOUR A1 - Amrhein, Frank A1 - Kehrer, Martin A1 - Schreck, Timo A1 - Bochtler, Ulrich A1 - Hellmann, Ralf A1 - Kaloudis, Michael T1 - More efficient curing of UV sensitive mounting materials JF - Practical metallography KW - Aushärtung Y1 - 2014 VL - 48 IS - 7 SP - 356 EP - 364 ER - TY - JOUR A1 - Bochtler, Ulrich A1 - Hellmann, Ralf A1 - Kaloudis, Michael T1 - Neuartige UV-Lichtquelle auf Leuchtdiodenbasis, Packaging und Hybridschaltungen JF - PLUS KW - Lumineszenzdiode Y1 - 2010 IS - 2 PB - Leuze-Verlag ER - TY - JOUR A1 - Dressler, Katharina A1 - Rauer, Miriam A1 - Kaloudis, Michael A1 - Dauwe, Stefan A1 - Herguth, Axel A1 - Hahn, Giso T1 - Nondestructive Characterization of Voids in Rear Local Contacts of PERC-Type Solar Cells JF - IEEE Journal of Photovoltaics N2 - In this paper, we present two nondestructive characterization methods for the detection of voids in rear local contacts of passivated emitter and rear-type solar cells, namely scanning acoustic microscopy and computer tomography. We compare both methods and include a comparison with electroluminescence measurements. It is shown in this paper that voids can easily be detected with both measurement types without any sample preparation. We found a good match of scanning acoustic microscopy (SAM) and computer tomography (CT), which is presented for this purpose for the first time. The investigation was carried out for different aluminum pastes. KW - Solarzelle Y1 - 2014 U6 - https://doi.org/10.1109/JPHOTOV.2014.2359745 VL - 2015 IS - 1 SP - 70 EP - 76 ER - TY - JOUR A1 - Wohlschlögel, Timo A1 - Kaloudis, Michael T1 - Praktische Oberflächenanalytik – Überblick über die Verfahren EDX, AES, XPS und SIMS JF - Galvanotechnik KW - Oberflächenanalyse Y1 - 2011 IS - 12 SP - 2637 EP - 2646 ER - TY - JOUR A1 - Kefer, Stefan A1 - Sauer, Theresia A1 - Hessler, Steffen A1 - Kaloudis, Michael A1 - Schmauß, Bernhard A1 - Hellmann, Ralf T1 - Robust Polymer Planar Bragg Grating Sensors Embedded in Commercial-Grade Composites JF - Polymers N2 - This contribution demonstrates the functionality of polymer planar Bragg grating (PPBG) sensors integrated into commercial-grade carbon fiber reinforced polymer (CFRP) components. Multiple CFRP specimens are generated by curing a stack of pre-impregnated fibers inside of a heated mechanical press, exposing the polymer sensor to a pressure of 7 bar and a temperature of 120 °C for 2 h. After integration, the sensor still exhibits a strong and evaluable signal. Subsequent flexural experiments reveal a linear response of the integrated sensor’s Bragg wavelength to the CFRP specimen’s maximum deflection. Additional findings demonstrate that the embedded PPBG can be used to detect plastic deformations of a CFRP workpiece, whereas a linear correlation of plastic deformation to the resulting Bragg signal offset is determined. A plausibility check of the obtained results is delivered by a comparison of three-point flexural experiments on bulk CFRP workpieces, without integrated sensors and additional specimens featuring external optical sensors affixed to their surface. It is found that PPBGs based on cyclic olefin copolymers are able to overcome the temperature-related limitations of traditional polymer-based optical sensors and can thus be directly integrated into commercial-grade composites during production. KW - Bragg grating sensors KW - carbon fiber reinforced polymers KW - cyclic olefin copolymers KW - Bragg-Reflektor KW - Optischer Sensor Y1 - 2020 UR - https://www.mdpi.com/2073-4360/12/3/715/htm U6 - https://doi.org/10.3390/polym12030715 VL - 12 IS - 3 SP - 715 EP - 715 ER -