Prof. Paul Hartmann Profile

Prof. Paul Hartmann

Director at JOANNEUM RESEARCH Forschungsgesellschaft mbH

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

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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

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

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

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Proceedings Article | 7 September 2016 Presentation + Paper

A study on Aerosol jet printing technology in LED module manufacturing

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

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

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

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Proceedings Article | 7 September 2016 Presentation + Paper

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

Franz Wenzl, Claude Leiner, Wolfgang Nemitz, Susanne Schweitzer, 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

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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

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

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

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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

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

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

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Proceedings Article | 18 September 2013 Paper

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

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

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

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

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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

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

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

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

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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

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

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Proceedings Article | 5 May 2012 Paper

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

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

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

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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

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

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

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

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Proceedings Article | 6 February 2012 Paper

Integrated waveguide sensor platform utilizing organic photodiodes

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

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

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

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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

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

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

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Proceedings Article | 3 February 2009 Paper

Up and down: color conversion for solid-state lighting

Paul Hartmann, Elisabeth Payrer, Peter Pachler, Stefan Tasch

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

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

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Proceedings Article | 18 November 2008 Paper

Novel solutions toward improved high power white LED light source

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

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

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Proceedings Article | 18 November 2008 Paper

Novel approaches for light control of high power LEDs

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

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, S. Tasch, M. Schweighart, P. Hartmann, E. Zinterl, L. Kuna, P. Pachler, J. Krenn

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

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Proceedings Article | 14 February 2008 Paper

Novel chip coating approaches to improve white LED technology

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

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

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Proceedings Article | 14 September 2007 Paper

Silicate phosphors and white LED technology: improvements and opportunities

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

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

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

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Proceedings Article | 12 September 2006 Paper

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

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

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

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Showing 5 of 24 publications

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