Dr. Olaf Brodersen Profile

Dr. Olaf Brodersen

at CiSMT

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Publications (11)

Proceedings Article | 5 March 2021 Presentation

Factors influencing the emission characteristics of UV LED chips: The modular system for module optimization

Indira Kaepplinger, Dennis Mitrenga, Guido Leibeling, Frank Gindele, Yoshio Kikuchi, Olaf Brodersen, Thomas Ortlepp

Proceedings Volume 11706, 117060J (2021) https://doi.org/10.1117/12.2575072

KEYWORDS: Ultraviolet light emitting diodes, Ultraviolet radiation, Light emitting diodes, Thermography, UV optics, Optical components, Deep ultraviolet, Water, Medical diagnostics, Medical devices

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Proceedings Article | 5 March 2021 Presentation

Integrated digitally adjustable step-down converter to control one individual or a series of UV-LED(s)

Olaf Brodersen, Konstantin Schmid, Christoph Heinze, Thomas Ortlepp, Peter Rotsch

Proceedings Volume 11706, 117060K (2021) https://doi.org/10.1117/12.2576789

KEYWORDS: Switches, Integrated circuits, Ultraviolet radiation, Temperature metrology, Synthetic aperture radar, Switching, Power supplies, Optical testing, Modulators, Medical equipment

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Proceedings Article | 1 March 2019 Presentation + Paper

Discussion on reliability issues for UVB and UVC LEDs

S. Nieland, M. Weizman, D. Mitrenga, P. Rotsch, M. Schaedel, O. Brodersen, T. Ortlepp

Proceedings Volume 10940, 1094009 (2019) https://doi.org/10.1117/12.2509418

KEYWORDS: Light emitting diodes, Ultraviolet light emitting diodes, Ultraviolet radiation, Reliability, Silver, Strontium, Skin, Manufacturing, Gold, UV optics

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The usage of UV LEDs is getting attractive for application such as phototherapy, plant growth, and disinfection due to the wavelength selective, narrow-band emission and a high potential for miniaturization of LED devices. Besides these benefits, the demands on optical power and long-term stability for these applications can often be well satisfied. For UVB LEDs most promising applications are in the field of medical skin therapy and novel concepts of horticulture and plant growth (irradiation of plants for the generation of phytamines or to reduce hormone-like mixtures). UVC applications focus on disinfection of air, surfaces and water at 265 nm or 280 nm. Each application field requires an individual UV dose, which is connected with the optical power output of the LED, and thus the number of LEDs and their long term stability. Typical doses for skin irradiation is 20 mJ/cm² at 310 nm and for water disinfection 20-60 mJ/cm² at 280 nm depending which target reduction factor log reduction of germicides is required. In this work a discussion on different factors influencing the reliability of LED modules, summarizing several years of research in this field will be given. Degradation effects are shown depending on LED design itself as well as the device assembly architecture including different mounting techniques. The most promising assembly technique was tested by a sample series of twice 400 single LED packages with a total yield of 87.7 % after mounting of UVB LEDs in single LED cases, cascading to an array on a main board by secondary soldering and burn-in of 48 hour at 50mA. In total 4% of the yield loss results by soldering issues of the LED on submount as well as another 8 % yield loss was measured after cascading of single LED packages on main board. Due to the burn-in process additional twenty UVB LEDs were lost. These reliability issues will be discussed using selected “state-of-the-art” LED device structures and examples of testing these LED devices in UV lighting lamp systems built at OSA opto Light will be given.

Proceedings Article | 1 March 2019 Paper

Enhanced heat dissipation for high-power UV LED devices using sintering

S. Nieland, D. Mitrenga, O. Brodersen, M. Schaedel, T. Ortlepp

Proceedings Volume 10940, 109401V (2019) https://doi.org/10.1117/12.2509438

KEYWORDS: Light emitting diodes, Silver, Ultraviolet light emitting diodes, Gold, Ultraviolet radiation, Resistance, Scanning electron microscopy, Thermography, Reliability, Polymers

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Higher optical power and higher UV doses come along with a higher operation temperature of UV LED based light sources. Silver sintered pastes offer a robust lead-free alternative to solder pastes increasing the lifetime of the device and enabling higher heat dissipation. Due to the design of UV LEDs, they have to be connected to a heat spreading submount by flip chip joining. Well established processes are flip chip soldering and thermal compression bonding. However, both methods do not achieve optimal heat dissipation in practice. Solder joining material offers a thermal conductivity in the range of 50-60 W/mK which can be further reduced by voids or uncovered areas. Gold contacts for thermal compression bonding offer excellent thermal conductivity of 320 W/mK, but show a maximum coverage of 50- 70%. Silver sinter paste adapted to the UV LED contact system, is a promising alternative flip chip joining material. In order to evaluate different joining methods, UV LED devices were assembled by thermal compression bonding, diffusion bonding, soldering and sintering and compared according to, thermal resistivity, optical-electrical and mechanical behavior and reliability issues. In addition, different silver sinter pastes were tested and their thermal resistivity was adjusted via processing parameters (pressurization, sintering temperature and time). For pressureless approaches the thermal conductivity and layer thickness are in the range of solder material or below. Using pressure for sintering, several advantages will be introduced. The interconnection thickness can be adjusted to be as thin as possible (below 5 micron), which enhanced the heat dissipation. A thin sintered layer of a few microns shows a lower shrinkage and a better adhesion to the joining partners. The thermal conductivity can be enhanced as well. After sintering, the silver interconnection layer is thermally stable up to 800 °C. These facts speak for sintering pastes as a real alternative for UV LED assembly.

Proceedings Article | 9 May 2018 Presentation + Paper

DNA analysis with UV-LEDs

Ch. Möller, M. Hentschel, Th. Hensel, A. Müller, Ch. Heinze, O. Brodersen, Th. Ortlepp

Proceedings Volume 10680, 1068013 (2018) https://doi.org/10.1117/12.2306761

KEYWORDS: Light emitting diodes, Ultraviolet radiation, Photodiodes, Fiber couplers, Absorption, Silicon, Diodes, Optical filters, UV optics, Analytical research

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Proceedings Article | 15 February 2018 Paper

Thermocompression bonding for high-power-UV LEDs

Indira Kaepplinger, Dominik Karolewski, Geert Brockmann, Thomas Ortlepp, Olaf Brodersen, Andreas Thies, Jens Rass, Sven Einfeldt, Neysha Lobo-Ploch, Christoph Stoelmacker, Frank Schnieder

Proceedings Volume 10554, 105541B (2018) https://doi.org/10.1117/12.2287720

KEYWORDS: Light emitting diodes, Ultraviolet radiation, Copper, Metals

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Proceedings Article | 16 May 2017 Paper

Tiny incident light angle sensor

D. Mitrenga, M. Schädel, A. Winzer, S. Völlmeke, K. Preuß, J. Freitag, O. Brodersen

Proceedings Volume 10231, 102312C (2017) https://doi.org/10.1117/12.2267135

KEYWORDS: Sensors, Optical sensors, Silicon, Solids, Control systems, Microopto electromechanical systems, Solar energy systems, General lighting, Photodiodes, Semiconducting wafers, Diodes, Calibration, Signal analyzers, Artificial neural networks, Diffusion, Signal analysis, Manufacturing

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Proceedings Article | 16 February 2017 Presentation + Paper

Influence of interconnection on the long-term reliability of UV LED packages

S. Nieland, D. Mitrenga, D. Karolewski, O. Brodersen, T. Ortlepp

Proceedings Volume 10124, 101240S (2017) https://doi.org/10.1117/12.2250289

KEYWORDS: Light emitting diodes, Reliability, Lamps, Ultraviolet light emitting diodes, Ultraviolet radiation, Gold, Aluminum nitride, Ceramics, Thermography, Power supplies

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Proceedings Article | 9 May 2012 Paper

Roughness sensor based on a compact optoelectronic emitter-receiver modules

Matthias Will, Olaf Brodersen, Arndt Steinke

Proceedings Volume 8439, 84390W (2012) https://doi.org/10.1117/12.922748

KEYWORDS: Sensors, Photodiodes, Light scattering, Manufacturing, Vertical cavity surface emitting lasers, Optoelectronics, Semiconductor lasers, Silicon, Diodes, Scattering

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Proceedings Article | 11 October 2011 Paper

Silicon micro sensors as integrated readout platform for colorimetric and fluorescence based opto-chemical transducers

Matthias Will, Tomas Martan, Olaf Brodersen

Proceedings Volume 8306, 83060B (2011) https://doi.org/10.1117/12.912798

KEYWORDS: Sensors, Luminescence, Transducers, Light emitting diodes, Silicon, Polymers, Oxygen, Semiconducting wafers, Carbon dioxide, Chemical analysis

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Opto-chemical transducer almost offers unlimited possibilities for detection of physical quantities. New technologies and research show a steady increasing of publications in the area of sensoric principles. For transfer to real world applications the optical response has to be converted into an electrical signal. An exceptional opto chemical transducer loses the attraction if complex and expensive instruments for analysis are requires. Therefore, the readout system must be very compact and producible for low cost. In this presentation, the technology platform as a solution for these problems will be presented. We combine micro structuring of silicon, photodiode fabrication, chip in chip mounting and novel assembly technologies for creation of a flexible sensor platform. This flexible combination of technologies allows fabricating a family of planar optical remission sensors. With variation of design and modifications, we are able to detect colorimetric, fluorescent properties of an sensitive layer attached on the sensor surface. In our sensor with typical size of 6mm x 6mm x 1mm different emitting sources based on LED's or laser diodes, multiple detection cannels for the remitted light and also measurement of temperature are included. Based on these sensors we proof the concept by demonstrating sensors for oxygen, carbon dioxide and ammonia based on colorimetric and fluorescent changes in the transducer layer. In both configurations, LED's irradiated the sensitive polymer layer through a transparent substrate. The absorption or fluorescence properties of dyed polymer are changed by the chemical reaction and light response is detected by PIN diodes. The signal shift is analyzed by using a computer controlled evaluation board of own construction. Accuracy and reliability of the remission sensor system were verified and the whole sensor system was experimentally tested in the range of concentrations from 50 ppm up to 100 000 ppm for CO2 and O2 Furthermore, we develop concepts to use the sensor also for interferometric detection of layer properties and the combination with capacitive structures on the surface. This allows detecting of thickness or refractive index variation of layers in future.

Proceedings Article | 18 November 2008 Paper

Optical sensor based on sensitive polymer layer

Matthias Will, Tomas Martan, Ralf Müller, Olaf Brodersen, Gerhard Mohr

Proceedings Volume 7138, 71380A (2008) https://doi.org/10.1117/12.817974

KEYWORDS: Polymers, Sensors, Light emitting diodes, Polymeric sensors, Optical sensors, Diodes, Transducers, PIN photodiodes, Carbon dioxide, Polymer thin films

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Showing 5 of 11 publications

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