Pr Marc TERNISIEN, Associate Professor, LAPLACE (France)

Session : OLED Technology

Contribution: Recent advances in OLED technologies

The emergence of the use of organic materials for commercial purposes in objects of everyday life has become increasingly important. By improving their lifetime, the OLEDs are now integrated in some applications such as MP3 players or mobile phones. They are increasingly used in the display as shown by the TV XEL-1 developed by Sony in 2007 (11-inch OLED made with a matrix).
Since the realization of the first organic light emitting diode (OLED = Organic Light-Emitting Diode) by Tang and Van Slyke for the Kodak company in 1987 until today, what were the various technical developments that made the future strongly oriented towards organic materials? What about the possibility of using these sources for the lighting of the future? What are the performances? Are there still technological barriers? How will they be used in the future? This presentation will give a non-exhaustive overview of possible answers to these questions.

 Mr Christphe MARTY, Engineer and Architect, Ingelux Consultant  (France)

Session : LED lighting users feedback

Contribution:  Pact led: An Adem Program on the quality of the LED lighting

LED program, funded by ADEME and handled by a consortium raised by the Cluster Lumière (CSTB, CEA, LNE, Ingélux, Philips, CNRS-ENTPE). It aims at developing a Led retrofit lamp for 20W and 35W dichroic lamps. This Led lamp will use 4 times less energy, and will provide the same quality of light. The assessment of the light quality represents the core part of the project, and it is the condition of ADEME for a support to the new lamp.
The conference will focus on the criterias chosen with Ademe to ensure the acceptance by the final users of the LED lamp. The process of lab testing and field testing with panels of observers will be presented. We will then highlight the reasons of disappointments of users concerning today’s LED retrofit lamps.

Mrs Stephanie MITTELHAM, Managing director, CELMA (Belgium)

Session : Economic aspects of LED market

Contribution: Efforts of the European lighting Industry to deliver high quality energy efficient LED lighting solutions

 The CELMA / ELC presentation will explain the activities of the European Lighting Industry, represented by ELC (Lightsources) and by CELMA (Luminaires and their components), to deliver high quality energy efficient LED lighting solutions. The main focus of the European Lighting industry is to assure that LED lighting in Europe brings an improvement of the Lighting Quality as well as a further increase of the Energy Efficiency of the lighting system.

Mr Claude WEISBUCH, Ecole Polytechnique Lab PMC (USA)

Session : Hight Brightness LED Technologies

Contribution: Getting the photons out of the LED



Once electricity has been transformed into photons within the semiconductor materials of an LED, sometimes with an efficiency close to 100%, a major task remains, that of getting these photons outside the LED.

Intrinsically, photons would remain inside the semiconductor materials which possess high indices of refraction. This is due to the total internal reflection phenomenon occurring when an inside photon strikes the semiconductor air interface at an angle larger than the critical angle. The fraction of light which is directly extracted to air is therefore only 2-6% per facet of the device, depending on the index of the semiconductor. Often, the light remaining trapped within the semiconductor is lost due to several dissipation channels existing within the device.

Various strategies are being used to increase such low values of light extraction, based either on geometrical optics (shaping substrates, texturing surfaces or substrate-semiconductor interfaces, using micro mirrors or lenses, …) or wave optics (relying on microcavity or photonic crystal effects).

We will discuss the pros and cons of these various approaches.

Mrs Caroline CRESPIN, Initiator of the Mood Lighting activity within Airbus, Lighting Creative in the private aviation(France)

Session : LED lighting user feedback

Contribution: The Use of the LEDs in the Cabins of Planes

 It is the advent of the LEDs that impulsed wide possibilities of lighting in the commercial aviation. So to answer the need of airlines, the Mood Lighting activity was created within the big aircraft manufacturer based in Blagnac near Toulouse, Airbus.

I will announce my experience feedback through the following fields of activity:

Introduction: the various technologies of lighting on all the programs (from 2004 to January, 2010): fluorescent tubes, different generations of LEDs, etc. The use of LEDs means a color lighting ambiances as a general illumination. That is the reason why we will mainly talk about the ambiant lighting.

Experience feedback on the ambiances lighting with LEDs:
1.  A380: follow-up of the development and the tests of lightings: special modes of programming. Lessons learnt.
2.  Comparison of felt color lighting ambiances: between the filtered fluorescent tubes and the LEDs in additive synthesis
3. The experience in scale 1 mock up with airlines representatives. It is the opportunity to be bathed into lighting ambiances varying along a programmed scenario in terms of color, saturation and intensity. I will give a summary of experiences demonstrating that our perception is fickle.

Special Applications: the LEDs for accent lightings and special bright effects.

Conclusion: the experience is definitively rich and diverse. In parallel, the same evolutions take place in the private aviation which equips its cabins almost exclusively with LEDs. Today LEDs are more and more applied on public areas.

Mr Ching-Cherng SUN, Director of the Institute of Lighting and Display Science and Distinguished Professor of the National Central University (Taiwan)

Session: Structure of LED products

Contribution: Optics and phosphor modeling for LEDs in package level

In this talk, we will discuss the modeling for optical light pattern as well as phosphor for light emitting diodes (LEDs) in package level. In modeling the LED for obtaining a precise optical model, we will introduce a simulation algorithm with Monte Carlo ray tracing incorporated with the mid-field concept in the evaluation of the model. In the proposed mid field rather than the near field in physics and far field of Fourier optics, the light intensity distribution by an LED changes from one distance to another.
Therefore, the optical model of LED can be said precise once is can predict the intensity distribution across at least 3 planes located in the mid-field region. Based on the mid-field model, we will present successful optical model for at least five different LEDs.

The second topic that we will present is the phosphor model. We will show a proposed model for precisely describing the color coordinate of a white LED. The concentration as well as the geometry of the phosphor covered on blue LED die will be studied to obtain the desired correlated color temperature (CCT) and luminous efficacy. We will start from the scattering model, go through the determination of the absorption coefficient and conversion coefficient to build up a precise phosphor model with Monte Carlo ray tracing with Mie scattering.

Finally, we will present the comparison between the simulation and the measurement.    

Mr Matthias SABATHIL,Head of modelling group, Osram Opto Semiconductors GmbH (Germany)

Session : Hight Brightness LED technologies

Contribution: Efficiency droop - the final frontier of InGaN LEDs

 In this presentation, we report on the latest advancements  in improving AlGaInN-based visible-light-emitting-diode (LED)  efficiency in epitaxy, chip, and package designs. We investigate the fundamental origin of the typical high current “droop” of  efficiency observed in such LEDs. We show that this effect is  most likely not caused by incomplete carrier injection or carrier  escape but that it is rather a fundamental material property of  InGaN/GaN-heterostructure-based light emitters. The droop can  be reduced in improved epitaxial LED active-layer designs. We  show how this can be achieved by lowering InGaN volume carrier  density in multiple quantum wells (MQWs) and thick InGaN layers.

Improved epitaxial MQW structures are then combined with  a new advanced chip concept. It is optimized for high efficiency at  high current operation and arbitrary scalability and can be manufactured  at low cost. This is accomplished by improving light extraction  efficiency, homogenizing the emission pattern, reducing  forward voltage, and lowering thermal resistance. The improved  high current efficiency can be fully exploited by mounting the chip  in the highly versatile new OSLON SSL package. It features very  stable package materials, a small footprint, and an electrically  isolated design decoupling electrical and thermal contacts.

Mrs Mia PAGET, Senior Research Engineer, Pacific Northwest National Laboratory (USA)

The United States Department of Energy (DOE)  launched the Commercially Available LED Product Evaluation and Reporting (CALiPER) program in 2006 to support testing of SSL products available for general illumination, using industry-approved test procedures. CALiPER applies a number of practices to ensure credibility of test results, such as purchasing testing samples anonymously, applying standardized measurement methodologies whenever possible, working in close cooperation with standards efforts, and benchmark testing of traditional products to enable direct comparisons.

The most essential standard for SSL measurement applied by CALiPER is the Illuminating Engineering Society IES-LM-79-08 Approved Method for Electrical and Photometric Measurements of Solid-State Lighting Products. Numerous other standards that are under development and related existing standards are also used by CALiPER to investigate other SSL quality characteristics and to provide feedback to manufacturers, testing laboratories and standards committees.

Examples of other types of CALiPER testing and investigations include long-term lumen depreciation and life projections, color shift and spatial uniformity, reliability of integral SSL products, in situ performance, dimming and flicker. With an evolving technology and rapidly maturing markets, testing of SSL products raises constant challenges: development or adaptation of testing methodologies, application of testing methods, creating credibility and awareness of test results, educating buyers and manufacturers, comparing results with more traditional lighting, and working with regulators on performance criteria, labeling, and verification of products.

CALiPER addresses these challenges and provides publically available test results and analyses for hundreds of SSL products.

Pr Marc FONTOYNONT. Director, Building Sciences Laboratory, ENTPE (France)

Session : Standardization and quality control

Contribution: Propositions to increase confidence in Solid State Lighting products worldwide


Solid State Lighting is a technology which carries tremendous hope, due to its potential to offer energy efficient solutions to an extremely large field of lighting applications. But issues of efficiency, reliability, cost, and quality control still need to be solved.

Various national energy agencies and governments of the OECD countries identified the potential and the risks related to the large scale replacement of actual lamps such as tungsten and compact fluorescent lamps by solid-state light sources.

Among them is the difficulty to organize, through regulation, and labels,  the progressive banning of lamps of low efficacy, if the customers do not get the guaranty that the replacement lamps offer at least comparable light output. The win-win approach appears mandatory, and benefits should be found for customers, lighting professionals and governments.

We will present progress of the new annex on SSL by the International Energy Agency, which has started September 2010 in Shanghai. It concerns quality insurance issues, agreement on SSL testing protocols, and suggestions to speed up standardization.