Prof. Paul Hartmann Profile

Prof. Paul Hartmann

Director at JOANNEUM RESEARCH Forschungsgesellschaft mbH

SPIE Involvement:

Author

Publications (24)

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

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

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Proceedings Article | 7 September 2016 Presentation + Paper

A study on Aerosol jet printing technology in LED module manufacturing

Andreas Rudorfer, Martin Tscherner, Christian Palfinger, Frank Reil, Paul Hartmann, Ioannis Seferis, Eugeniusz Zych, Franz Wenzl

Proceedings Volume 9954, 99540E (2016) https://doi.org/10.1117/12.2237737

KEYWORDS: Dielectrics, Atmospheric particles, Head, Glasses, Silicon, Manufacturing, Light emitting diodes, Aerosols, Printing, Additive manufacturing

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

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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

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

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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

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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

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

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Proceedings Article | 18 September 2013 Paper

PyzoFlex: a printed piezoelectric pressure sensing foil for human machine interfaces

M. Zirkl, G. Scheipl, B. Stadlober, C. Rendl, P. Greindl, M. Haller, P. Hartmann

Proceedings Volume 8831, 883124 (2013) https://doi.org/10.1117/12.2025235

KEYWORDS: Ferroelectric polymers, Temperature metrology, Signal processing, Analog electronics, Resistance, Electrodes, Printing, Ferroelectric materials, Human-machine interfaces, Sensors

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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

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

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

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

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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 | 21 February 2012 Paper

All printed touchless human-machine interface based on only five functional materials

G. Scheipl, M. Zirkl, A. Sawatdee, U. Helbig, M. Krause, E. Kraker, P. Andersson Ersman, D. Nilsson, D. Platt, P. Bodö, S. Bauer, G. Domann, A. Mogessie, Paul Hartmann, B. Stadlober

Proceedings Volume 8258, 82580P (2012) https://doi.org/10.1117/12.908602

KEYWORDS: Electronics, Human-machine interfaces, Capacitance, Dielectrics, Inkjet technology, Carbon, Transistors, Printing, Electrodes, Sensors

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Proceedings Article | 6 February 2012 Paper

Integrated waveguide sensor platform utilizing organic photodiodes

Bernhard Lamprecht, Martin Sagmeister, Elke Kraker, Paul Hartmann, Georg Jakopic, Stefan Köstler, Harald Ditlbacher, Nicole Galler, Joachim Krenn, Birgit Ungerböck, Tobias Abel, Torsten Mayr

Proceedings Volume 8234, 82341H (2012) https://doi.org/10.1117/12.908432

KEYWORDS: Positron emission tomography, Oxygen, Metals, Surface plasmons, Photodiodes, Luminescence, Refractive index, Waveguide sensors, Waveguides, Sensors

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

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Proceedings Article | 3 February 2009 Paper

Up and down: color conversion for solid-state lighting

Paul Hartmann, Peter Pachler, Elisabeth Payrer, Stefan Tasch

Proceedings Volume 7231, 72310X (2009) https://doi.org/10.1117/12.809033

KEYWORDS: General lighting, Radium, LED lighting, Near infrared, Light sources, Solid state lighting, Oxygen, Quantum efficiency, Blue light emitting diodes, Light emitting diodes

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

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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

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

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

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Proceedings Article | 14 September 2007 Paper

Silicate phosphors and white LED technology: improvements and opportunities

Christian Sommer, Franz Wenzl, Paul Hartmann, Peter Pachler, Marko Schweighart, Guenther Leising, Stefan Tasch

Proceedings Volume 6669, 66690O (2007) https://doi.org/10.1117/12.734191

KEYWORDS: Silicates, Coating, LED lighting, Refractive index, Scattering, Light scattering, Silicon, Sensors, Particles, Light emitting diodes

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

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Showing 5 of 24 publications

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