Dr. Christian Sommer Profile

Dr. Christian Sommer

Scientist at JOANNEUM RESEARCH Forschungsgesellschaft mbH

SPIE Involvement:

Author

Publications (25)

Proceedings Article | 17 May 2022 Presentation + Paper

Human activity recognition based on fusing inertial sensors with an optical receiver

Ziad Salem, Felix Lichtenegger, Andreas Peter Weiss, Claude Leiner, Christian Sommer, Franz-Peter Wenzl

Proceedings Volume 12139, 1213906 (2022) https://doi.org/10.1117/12.2621187

KEYWORDS: Receivers, Sensors, Detection and tracking algorithms, Gyroscopes, Optical simulations, Data modeling, Data fusion, Feature extraction, Magnetometers, Source mask optimization

Read Abstract +

Proceedings Article | 17 May 2022 Presentation + Paper

A combined optical-electronic simulation approach for a comprehensive discussion of the performance of visible light positioning under tunable lighting conditions

Saman Zahiri-Rad, Felix Lichtenegger, Claude Leiner, Andreas Peter Weiss, Christian Sommer, Erich Leitgeb

Proceedings Volume 12139, 1213902 (2022) https://doi.org/10.1117/12.2622092

KEYWORDS: Light emitting diodes, Receivers, Light sources and illumination, Optical simulations, Photodiodes, Electronic circuits, Light sources, Geometrical optics, Computer simulations

Read Abstract +

Proceedings Article | 17 May 2022 Presentation + Paper

Compact angle diversity receiver concept for visible light positioning

Felix Lichtenegger, Claude Leiner, Christian Sommer, Andreas Weiss, Andreas Kröpfl, Saman Zahiri-Rad

Proceedings Volume 12138, 121380J (2022) https://doi.org/10.1117/12.2621579

KEYWORDS: Receivers, Fresnel lenses, Prototyping, Visible radiation, CMOS sensors, Sensors, Lithography, Ray tracing, Photodetectors

Read Abstract +

Proceedings Article | 12 September 2021 Presentation + Paper

Simulation of fingerprinting based Visible Light Positioning without the need of prior map generation

Felix Lichtenegger, Claude Leiner, Christian Sommer, Andreas Weiss, Franz Wenzl, Ziad Salem

Proceedings Volume 11874, 118740I (2021) https://doi.org/10.1117/12.2596841

KEYWORDS: Receivers, Light emitting diodes, Photodiodes, Visible radiation, Light sources and illumination, Computer simulations

Read Abstract +

SPIE Journal Paper | 17 February 2017

Optical design of freeform micro-optical elements and their fabrication combining maskless laser direct write lithography and replication by imprinting

Ladislav Kuna, Claude Leiner, Wolfgang Nemitz, Frank Reil, Paul Hartmann, Franz-Peter Wenzl, Christian Sommer

JPE, Vol. 7, Issue 01, 016002, (February 2017) https://doi.org/10.1117/12.10.1117/1.JPE.7.016002

KEYWORDS: Optical components, Light emitting diodes, Optical design, Photoresist materials, Direct write lithography, 3D modeling, Optics manufacturing, Optical simulations, Light sources, Freeform optics

Read Abstract +

Proceedings Article | 27 September 2016 Presentation + Paper

Manufacturing of freeform micro-optical elements by mask-less laser direct write lithography and replication by imprinting

L. Kuna, C. Leiner, S. Ruttloff, W. Nemitz, F. Reil, P. Hartmann, F. Wenzl, C. Sommer

Proceedings Volume 9949, 99490C (2016) https://doi.org/10.1117/12.2237776

KEYWORDS: Freeform optics, Optics manufacturing, Direct write lithography, Manufacturing, 3D modeling, Photoresist materials, Light emitting diodes, Optical components, Data modeling, Light sources and illumination

Read Abstract +

Proceedings Article | 7 September 2016 Presentation + Paper

Smart freeform optics solution for an extremely thin direct-lit application

Claude Leiner, Wolfgang Nemitz, Susanne Schweitzer, Franz Wenzl, Ladislav Kuna, Frank Reil, Paul Hartmann, Christian Sommer

Proceedings Volume 9955, 99550E (2016) https://doi.org/10.1117/12.2237771

KEYWORDS: Light emitting diodes, Diffusers, Freeform optics, Lenses, Light sources, Optical components, Scattering, Light sources and illumination, Bismuth, 3D acquisition

Read Abstract +

Proceedings Article | 7 September 2016 Presentation + Paper

Improving the effectiveness of photovoltaic devices by light guiding optical foils

C. Leiner, F. P. Wenzl, C. Sommer, G. Peharz

Proceedings Volume 9955, 995508 (2016) https://doi.org/10.1117/12.2237866

KEYWORDS: Solar cells, Photovoltaics, Optical design, Polymers, Optical simulations, Solar energy, Prisms, Crystals, Active optics, Photovoltaic materials

Read Abstract +

Proceedings Article | 27 April 2016 Paper

Smart freeform optics solution for an extremely thin direct-lit application

Claude Leiner, Wolfgang Nemitz, Susanne Schweitzer, Franz P. Wenzl, Christian Sommer

Proceedings Volume 9889, 988911 (2016) https://doi.org/10.1117/12.2227647

KEYWORDS: Light emitting diodes, Freeform optics, Light sources and illumination, Lenses, LED lighting, Optical design, Optical components, General lighting, Diffusers, Solid state lighting, Bismuth, Light sources, Detection and tracking algorithms, Optics manufacturing

Read Abstract +

Light-emitting diodes (LEDs) based lighting solutions offer many advantages like the huge potential for energy saving, long lifetime, high reliability and the compact size compared to incandescent light bulbs. Especially the last-mentioned aspect favors new concepts for the design and integration of light points and luminaires. In case of a direct-lit system for general lighting applications the LEDs are separated by a certain distance, arranged in a regular array and illuminate an out-coupling surface which is placed in a certain height above the LED array. One approach to fulfill the demand of a uniform luminance of the out-coupling surface is to replace the surface by a diffuser sheet. In order to allow for a flat luminaire design the distance of the out-coupling surface has to be modified synchronously with a variation of the distance between the LEDs. This means, in order to maintain the uniformity of the luminance the distance to height ratio (DHR) of the optical arrangement has to be kept constant. A (from the viewpoint of costs desirable) reduction of the number of the LEDs and as a consequence thereof an increase of the DHR value can be achieved by using additional optical elements like, e.g., freeform optics. However, this can cause additional design problems due to the size of such optical elements.

In this contribution we discuss a smart design of an extremely flat direct-lit luminaire for general lighting applications. The main advantage of this concept is the increased DHR ratio compared to diffuser sheet only-approaches and a smaller thickness of the whole set-up compared to common freeform approaches. For this demand we have designed very thin freeform optical elements with a maximal height of 75 μm that allow to maintain a uniform illumination in direct-lit applications using an LED-array with a comparably large distance between the individual LEDs. The presented design concept in addition emphasizes the use of cost-effective manufacturing methods like grey scale laser lithography for mastering and roll-to-roll processing for large area manufacturing of these optical elements.

Proceedings Article | 23 September 2015 Paper

Combining ray-tracing and FDTD to enable the simulation of complex optical devices in an iterative simulation process with reduced simulation effort

Claude Leiner, Wolfgang Nemitz, Susanne Schweitzer, Franz P. Wenzl, Gerhard Peharz, Christian Sommer

Proceedings Volume 9630, 96300T (2015) https://doi.org/10.1117/12.2191257

KEYWORDS: Finite-difference time-domain method, Matrices, Interfaces, Computer simulations, Optical simulations, Diffractive optical elements, Optical components, Geometrical optics, Device simulation, Silver

Read Abstract +

Proceedings Article | 25 September 2014 Paper

The impact of individual materials parameters on color temperature reproducibility among phosphor converted LED sources

Susanne Schweitzer, Wolfgang Nemitz, Christian Sommer, Paul Hartmann, Paul Fulmek, Johann Nicolics, Peter Pachler, Hans Hoschopf, Franz Schrank, Gregor Langer, Franz Wenzl

Proceedings Volume 9190, 91900S (2014) https://doi.org/10.1117/12.2061921

KEYWORDS: Light emitting diodes, Refractive index, Particles, Silicon, Reflectivity, LED lighting, Sensors, Solid state lighting, Light, Blue light emitting diodes

Read Abstract +

Proceedings Article | 25 September 2014 Paper

Foil based optical elements for beam shaping and color homogenization of phosphor converted white LED sources

Franz Wenzl, Wolfgang Nemitz, Ladislav Kuna, Christian Sommer, Paul Fulmek, Johann Nicolics, Peter Pachler, Hans Hoschopf, Franz Schrank, Gregor Langer, Paul Hartmann

Proceedings Volume 9190, 91900A (2014) https://doi.org/10.1117/12.2061944

KEYWORDS: Collimators, Light emitting diodes, Light, Light sources, Optical components, Beam shaping, Collimation, Lenses, Positron emission tomography, Integrated optics

Read Abstract +

Proceedings Article | 12 September 2014 Paper

A combined simulation approach using ray-tracing and finite-difference time-domain for optical systems containing refractive and diffractive optical elements

Christian Sommer, Claude Leiner, Susanne Schweitzer, Franz-Peter Wenzl, Ulrich Hohenester, Paul Hartmann

Proceedings Volume 9193, 91930F (2014) https://doi.org/10.1117/12.2061743

KEYWORDS: Waveguides, Finite-difference time-domain method, Diffraction gratings, Interfaces, Optical components, Diffractive optical elements, Sensors, Diffraction, Optical simulations, Error analysis

Read Abstract +

Proceedings Article | 30 September 2013 Paper

Thermal and optical aspects of glob-top design for phosphor converted white LED light sources

Christian Sommer, Paul Fulmek, Johann Nicolics, Susanne Schweitzer, Wolfgang Nemitz, Paul Hartmann, Peter Pachler, Hans Hoschopf, Franz Schrank, Gregor Langer, Franz Wenzl

Proceedings Volume 8835, 88350J (2013) https://doi.org/10.1117/12.2024887

KEYWORDS: Light emitting diodes, Reflectivity, Thermography, Blue light emitting diodes, LED lighting, Particles, Silicon, Absorption, 3D modeling, Photons

Read Abstract +

Proceedings Article | 30 September 2013 Paper

The impact of the color conversion element configuration on its thermal response in phosphor converted LEDs

Franz Wenzl, Paul Fulmek, Christian Sommer, Paul Hartmann, Peter Pachler, Hans Hoschopf, Franz Schrank, Gregor Langer, Johann Nicolics

Proceedings Volume 8835, 88350N (2013) https://doi.org/10.1117/12.2024886

KEYWORDS: Light emitting diodes, Blue light emitting diodes, Absorption, Silicon, Particles, Optical simulations, Light, Quantum efficiency, Thermography, 3D modeling

Read Abstract +

Proceedings Article | 7 May 2013 Paper

Multi-scale simulation of an optical device using a novel approach for combining ray-tracing and FDTD

Claude Leiner, Susanne Schweitzer, Volker Schmidt, Maria Belegratis, Franz-Peter Wenzl, Paul Hartmann, Ulrich Hohenester, Christian Sommer

Proceedings Volume 8781, 87810Z (2013) https://doi.org/10.1117/12.2017423

KEYWORDS: Finite-difference time-domain method, Diffraction gratings, Optical components, Diffractive optical elements, Interfaces, 3D modeling, Computer simulations, Geometrical optics, Optical simulations, Scanning electron microscopy

Read Abstract +

Optimizing the properties of optical and photonic devices calls for the need to control and manipulate light within structures of different length scales, ranging from sub-wavelength to macroscopic dimensions. Working at different length scales, however, requires different simulation approaches, which have to account properly for various effects such as polarization, interference, or diffraction: at dimensions much larger than the wavelength of light common ray-tracing techniques are conveniently employed, while in the (sub-)wavelength regime more sophisticated approaches, like the socalled finite-difference time-domain (FDTD) technique, are used. Describing light propagation both in the (sub-)wavelength regime as well as on macroscopic length scales can only be achieved by bridging between these two approaches. Unfortunately, there are no well-defined criteria for a switching from one method to the other, and the development of appropriate selection criteria is a major issue to avoid a summation of errors. Moreover, since the output parameters of one simulation method provide the input parameters for the other one, they have to be chosen carefully to ensure mathematical and physical consistency. In this contribution we present an approach to combine classical ray-tracing with FDTD simulations. This enables a joint simulation of both, the macro- and the microscale which refer either to the incoherent or the coherent effects, respectively. By means of an example containing one diffractive optical element (DOE) and macroscopic elements we will show the basic principles of this approach and the simulation criteria. In order to prove the physical correctness of our simulation approach, the simulation results will be compared with real measurements of the simulated device. In addition, we will discuss the creation of models in FDTD based on different analyze techniques to determine the dimensions of the DOE, as well as the impact of deviations between these different FDTD models on the simulation results.

Proceedings Article | 15 October 2012 Paper

The impact of the silicone encapsulation layers on the white light quality of phosphor converted LEDs

Susanne Schweitzer, Christian Sommer, Paul Hartmann, Wolfgang Nemitz, Peter Pachler, Hans Hoschopf, Gregor Langer, Paul Fulmek, Johann Nicolics, Franz Wenzl

Proceedings Volume 8484, 84840N (2012) https://doi.org/10.1117/12.929950

KEYWORDS: Silicon, Light emitting diodes, Refractive index, Light, Solid state lighting, Coating, Sensors, Blue light emitting diodes, General lighting, Particles

Read Abstract +

Proceedings Article | 15 October 2012 Paper

White light quality of phosphor converted LEDs from a phosphor materials perspective of view: an evaluation based on combined thermal and optical simulations

Franz-Peter Wenzl, Christian Sommer, Paul Hartmann, Peter Pachler, Hans Hoschopf, Gregor Langer, Paul Fulmek, Johann Nicolics

Proceedings Volume 8484, 848403 (2012) https://doi.org/10.1117/12.929970

KEYWORDS: Light emitting diodes, Quantum efficiency, Optical simulations, Particles, Absorption, Silicon, Blue light emitting diodes, Photons, Convection, Light

Read Abstract +

Proceedings Article | 5 May 2012 Paper

A simulation procedure for light-matter interaction at different length scales

Claude Leiner, Wolfgang Nemitz, Franz Wenzl, Paul Hartmann, Ulrich Hohenester, Christian Sommer

Proceedings Volume 8429, 84290L (2012) https://doi.org/10.1117/12.922404

KEYWORDS: Finite-difference time-domain method, Interfaces, Near field, Diffraction, Diffractive optical elements, Optical components, Near field optics, Photonic devices, Optical properties, MATLAB

Read Abstract +

The development of photonic devices with tailor-made optical properties requires the control and the manipulation of light propagation within structures of different length scales, ranging from sub-wavelength to macroscopic dimensions. However, optical simulation at different length scales necessitates the combination of different simulation methods, which have to account properly for various effects such as polarization, interference, or diffraction: At dimensions much larger than the wavelength of light common ray-tracing (RT) techniques are conveniently employed, while in the subwavelength regime more sophisticated approaches, like the so-called finite-difference time-domain (FDTD) technique, are needed. Describing light propagation both in the sub-wavelength regime as well as at macroscopic length scales can only be achieved by bridging between these two approaches. In this contribution we present on the one hand a study aiming at the determination of the intermediate size range for which both simulation methods are applicable and on the other hand an approach for combining classical ray-tracing with FDTD simulation in order to handle optical elements of large sizes. Generally, the interface between RT and FDTD is restricted to very small sample areas. Nevertheless, many real world optical devices use e.g. diffractive optical elements (DOEs) having comparably large areas in the order of 1-2 mm² (or larger). Therefore, one has to develop strategies in order to handle the data transfer between FDTD and RT also for structures of such larger size scales. Our approach in this regard is based on the symmetries of the structures. In this way support programs like e.g. MATLAB can be used to replicate the near-field of a single structure and to merge it to the near-field of a larger area. Comparisons of RT and FDTD simulations in the far-field can be used to validate the physical correctness of this approach. With such procedure it is possible to optimize light propagation effects at both the macro- and microscale and to exploit their whole potential for the manipulation and optimization of optical and photonic devices.

Proceedings Article | 18 August 2010 Paper

A comprehensive study on the parameters effecting color conversion in phosphor converted white light emitting diodes

C. Sommer, F. P. Wenzl, F. Reil, J. Krenn, P. Pachler, S. Tasch, P. Hartmann

Proceedings Volume 7784, 77840D (2010) https://doi.org/10.1117/12.860387

KEYWORDS: Light emitting diodes, Refractive index, Particles, Light scattering, Scattering, Atmospheric particles, Blue light emitting diodes, Sensors, Light, Light sources and illumination

Read Abstract +

Proceedings Article | 18 November 2008 Paper

Novel approaches for light control of high power LEDs

Ladislav Kuna, Franz Wenzl, Christian Sommer, Anja Haase, Ernst Zinterl, Joachim Krenn, Paul Hartmann, Peter Pachler, Marko Schweighart, Stefan Tasch, Günther Leising

Proceedings Volume 7138, 71382B (2008) https://doi.org/10.1117/12.818082

KEYWORDS: Light emitting diodes, Sapphire, Silicon, Confocal microscopy, Objectives, Atomic force microscopy, Image enhancement, Solid state lighting, Light sources and illumination, Laser processing

Read Abstract +

Proceedings Article | 18 November 2008 Paper

Novel solutions toward improved high power white LED light source

Franz Wenzl, Christian Sommer, Ladislav Kuna, Ernst Zinterl, Joachim Krenn, Paul Hartmann, Peter Pachler, Marko Schweighart, Stefan Tasch, Günther Leising

Proceedings Volume 7138, 71382C (2008) https://doi.org/10.1117/12.818083

KEYWORDS: Light emitting diodes, Absorption, Light sources, Blue light emitting diodes, Light, Sensors, Particles, LED lighting, Solid state lighting, Coating

Read Abstract +

Proceedings Article | 23 September 2008 Paper

Predicting solutions toward improved high power white LED light sources: a combined theoretical and experimental study

C. Sommer, F. Wenzl, L. Kuna, E. Zinterl, J. Krenn, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch

Proceedings Volume 7103, 710309 (2008) https://doi.org/10.1117/12.797453

KEYWORDS: Light emitting diodes, Sensors, Light sources, Silicon, Particles, Light scattering, Blue light emitting diodes, Scattering, Goniophotometry, Light

Read Abstract +

Proceedings Article | 14 February 2008 Paper

Novel chip coating approaches to improve white LED technology

Paul Hartmann, Marko Schweighart, Christian Sommer, Franz-P. Wenzl, Ernst Zinterl, Hans Hoschopf, Peter Pachler, Stefan Tasch

Proceedings Volume 6910, 69101A (2008) https://doi.org/10.1117/12.764477

KEYWORDS: Light emitting diodes, LED lighting, Coating, Blue light emitting diodes, General lighting, Technetium, Semiconductors, Headlamps, Computer simulations, Quantum efficiency

Read Abstract +

Proceedings Article | 12 September 2006 Paper

White LEDs and modules in chip-on-board technology for general lighting

Paul Hartmann, Franz Wenzl, Christian Sommer, Peter Pachler, Hans Hoschopf, Marko Schweighart, Martin Hartmann, Ladislav Kuna, Georg Jakopic, Guenther Leising, Stefan Tasch

Proceedings Volume 6337, 63370I (2006) https://doi.org/10.1117/12.682988

KEYWORDS: Light emitting diodes, General lighting, Sensors, Light sources and illumination, Light sources, Optical simulations, Absorption, Light scattering, Electrodes, Blue light emitting diodes

Read Abstract +

Showing 5 of 25 publications

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years