LpS Event: A Perfect Platform for New Ideas and Innovations

This year, approximately 1500 visitors and attendees came to Bregenz to hear about the latest technologies and research results from over 100 expert speakers. After the talks, many of the symposium attendees took advantage of the supplementary programs or went directly to one of the booths occupied by specialists from over 100 companies to discuss their newly gained knowledge.

More people than ever before attended the opening session with keynotes from the Nobel laureate Professor Shuji Nakamura, Diederik van Stoppelaar and Heinz Seyringer. In his keynote, Mr. Seyringer talked about the research programs within the European Community while Mr. van Stoppelar gave details about the challenges, opportunities and focus of the EU Commission as well as the impact of the latest trends in European policies within the lighting industry. This once in a lifetime chance to see Professor Nakamura live and the chance to meet him personally was probably one of the reasons such a big audience was attracted to the ceremony. And Prof. Nakamura didn’t disappoint anyone’s expectations. The audience could feel how ambitions Prof. Nakamura is when he told them how his work started and how he made his invention. He also impressed the audience with the fact that GaN-on- Sapphire blue LEDs were only at their starting point. He then went on to tell them about his GaN-on-GaN technology and also the future of white laser if the costs can be reduced. Prof. Nakamura finished by emphasizing the need to focus on light quality and tailoring LED lighting to the natural needs of humans - providing light that mimics sunlight as closely as possible.

The opening ceremony was also the platform to honor Dr. Rubén D. Costa, the winner of the 3rd LED professional Scientific Award. Dr. Guenther Sejkora, Innovation and Science Manager at Luger Research and Dr. Michael Schrempp, Global Head of Green Tech Solutions at Munich Re, awarded Dr. Costa a trophy and a check for 3,000 Euros. The advisory board selected his paper, entitled “Bio-Inspired White Hybrid Light-Emitting Diodes” by virtue of its novelty, good explanation, proof of concept and the potential to change the lighting scene. The original article can be read on page 32 of this issue.

From left to right: Siegfried Luger (organizer of the LpS 2016), Dr. Guenther Sejkora, Dr. Rubén D. Costa (winner of the LED professional Scientific Award) and Dr. Michael Schrempp from the award sponsor, Munich Re

The quality of the submissions was very high again this year. The top five papers after Dr. Costa’s paper can be read throughout the coming year in issues 59 to 63. In order of their publication they are: “Lifetime Calculation of White HP-LEDs from 16,000 Hours Aging Data” by Dipl.-Phys. Max Wagner, Technical University Darmstadt (LpR 59), “Optimization of Roadway Lighting Optics for Environment Adaptive Spatial Light Distribution” by Viktor Zsellér (LpR 60), “New Glass-Based Phosphors for White LEDs” by Dr. Franziska Steudel, Fraunhofer Application Center IMWS (LpR 61), “LED-Retrofit based on AlGaN/ GaN-on-Si Field-Effect Transistor Drivers” by Andreas Zibold MSc, Fraunhofer Institute IAF (LpR 62) and “Measurement of Angular and Spatial Resolved Spectra Rayfiles with Conventional Nearfield Goniophotometers and Standard Optical Filters” by Ingo Roscholl MSc. Karlsruhe Institute of Technology (LpR 63).

The Governor of Vorarlberg, Mag. Karlheinz Ruedisser, welcomed Prof. Nakamura to the region

Lectures: Practical Approaches Supplement Theory

This year’s symposium program was characterized by an increasing number of lectures that dealt with applicability and usability of LED lighting products. This addition to straightforward technical lectures was well received and takes the new general trend in the lighting ecosystem that was also emphasized in the keynotes, the press conference, workshops and several discussions into account. Improving light quality and not efficacy is the new top requirement that will provide the appropriate light for different applications and demands. This fact became especially apparent in the lighting design session lectures.

Dr. Peter Bodrogi from the TU Darmstadt talked about the seemingly continuous story of color quality metrics. In his lecture entitled “Color Quality of LED Illumination: Metrics and Experimental Data”, he pointed out that the CRI is a measure to the “realness” or “fidelity” of color appearance. With LEDs and the current visual habits, it turned out that “color preferences” and “color vividness” are more important in most indoor lighting situations. While some new proposals like CQS, Qp/Qg, MCRI, Rf/Rg indices take some aspects into account, none of them is easily applicable and the depiction is often too confusing, especially for end-users. Therefore his team took a semantic categorization approach to find out how indices need to be compared and where the acceptance limits are. The researchers found that different combinations of preference, naturalness and vividness cause a similar acceptance. They emphasize that not any combination might be equally useful in different applications: “For office lighting and long-term stays, color naturalness implying moderate Chroma enhancement can be considered. For home lighting or shop lighting for shorter stays, color preference might be appropriate. Finally, for accent lighting (e.g. theatre scenes or discotheques), color vividness can be chosen.”

Dr. Susanne Schweitzer from Joanneum Research presented the research group’s findings about “Gender and Age Specific Preferences Regarding Lighting Conditions for Activation and Relaxation”, another aspect of light quality. The data showed that there are clear differences in the lighting conditions preferred for these two situations. Some combined gender and age specific differences were also apparent. She confessed that the meaning about the influence of CCT on humans reported in the literature is diverse and her conclusions suggest that further research is in progress when she announced that, “…the influence of the deviation from the Planckian locus (u’v’) and results from questions regarding gender-related preferences of light and light-technology will be discussed in upcoming publications.”

The well-attended sessions were informative and exciting

Bartenbach’s Head of Research, Mag. Wilfried Pohl, summarized his knowledge on “Light and Health - Newest Research Findings and its Applications”. Based on some earlier studies that already suggest that light sources with an attenuated portion of short wavelengths may have a lower impact on nighttime circadian parameters, Bartenbach investigated such light sources and light conditions that do not meet international standards for interior lighting. The study showed that such light conditions did not impair cognitive performance (sustained attention and working memory) and mood parameters, and can reduce the disruption of circadian parameters during the night. Several research results of the team suggest that true HCL would be beneficial. Nevertheless, the researchers admit that costs and the technical implementation of the requested dynamic lighting solutions are still big issues.

In the same session, architect and lighting designer Ruairí O’Brien’s talk “High Quality Lighting Designs with SSL - Practical Examples and the New Role of Lighting Designers” focused on the responsibility of lighting designers to use the technology carefully and attentively. He told the technicians that light and illumination are more than just lux and lumens. He also emphasized the quality of light and darkness and when he pleaded for “re-darkness”. Mr. O’Brien asked for a more subtle artificial illumination that does not compete with natural light, allowing “wonderful sights of architecture as it was thought in its largeness, its true dimensions, and its materiality against the immateriality of light”.

“Cultural Aspects in Lighting Design with LEDs - Case Study Guzhen Town, PRC” was the topic presented by the architect Roberto Corradini. His appeal to take the culture, region, landscape and environment more into account when planning outdoor lighting in cities could give technicians and luminaire manufacturers a clue as to what lighting designers are expecting from them in the future. His concept for Guzhen Town asks for a new interpre¬tation of a Chinese historical lantern, not a simple copy of it and even less a standard street light head. The lantern has to be designed using the new technology providing modern, efficient, high quality light.

The other sessions were also characterized by numerous lectures on light quality aspects and fully covered with practice-oriented lectures.

In “System Quality” for instance, Peter Erwin presented “Theory and Practical Measurement Results of Modulated Light”. He proposed a new flicker metrics, the Compact Flicker Degree (CFD) with the aim to simplify labeling of LED lighting products in respect to flicker quality. His approach also takes much higher flicker frequencies into account than current standards or labels. This is a topic that has been discussed in earlier LpR issues.

The spirit of researchers like Dr. Rubén D. Costa and lighting designers like Ruairí O’Brien inspired the attendees

In the same session, Dipl.-Ing Margret Hedrich-Goeppert from Neumueller Electronics also discussed “Flicker of LED Light Sources”.

The “Engineering” session was dominated by optics and thermal management topics that could be an indication that the technology in these fields still needs some advances to fulfill all expectations. Obviously, innovative companies are working on these topics to find solutions that eliminate current deficiencies, limitations and bottlenecks - always having the application and usability in mind. Passive and active thermal management approaches for different applications were proposed and discussed. Likewise, advanced optical coatings, microstructures and beam shaping technologies were presented.

As the session title “Applications” suggests, the presentations in this track were very practice-oriented. Especially noticeable was the fact that a good part of these lectures was about optical systems for outdoor lighting. This might also be seen as an indication of which application still has a high demand for improvements. Very interesting beam shaping solutions were presented, a comparison of refractive and reflective optics and an optimization approach for illumination under different ambient situations.

Workshops and Forums: Informative and Hands-On

In parallel to the conference, renowned speakers and discussion partners were invited by various organizations and companies to lead 8 workshops and forums covering the topics of alternative light sources, spectrally tunable LED, OLED, horticulture lighting, SSL measurement, risk management, IoT and Artificial Intelligence (AI). This broad range of topics certainly played a role in the good attendance record and positive opinions of the attendees.

The International Solid State Lighting Alliance (ISA) not only had their official meeting in Bregenz, but they also held the ISA Forum with a broad range of topics, from cooperation between countries and organizations to risk assessment and management, to IoT in smart cities and SSL beyond illumination. Several well-known personalities, among them, Ms. Ling Wu, President of ISA, Huijian Bo, Project Director at Huawei Technologies, and Dr. Norman Bardsley, Chief Analyst of ISA Research (who later agreed to a Tech Talk Bregenz about OLED technology with LED professional), shared their knowledge and were available for discussions.

The existence of alternative light sources is often ignored because LEDs have reached a very high standard and the potential has not yet been exhausted. The Photonics Cluster Austria & Switzerland covered this topic demonstrating that there are applications where other solutions still make sense. Laser light offers several advantages. No droop and better controllability are just two, which also were mentioned by Prof. Nakamura in his keynote speech. Due to the high costs, this technology is mostly used in professional or special applications like instruments or cinema projection but not in general lighting. One of the rare lighting applications is in automotive, more precise in luxury cars where costs are less important. Besides the technology and advantages, limitations were also discussed.

Minich Re invited attendees to their forum, followed by a casual get together. In collaboration with DEKRA, they informed those present about global market trends, manufacturing risks and long-term warranties to be used as unique selling propositions, and the emerging new risks that come from cyber and IoT applications. They summed up by explaining their financing models and risk transfer solutions for large-scale LED investment projects.

The theoretical part of the workshops were often followed by a demonstration, hands-on or practical exercise

The APIL “Design and Technology” forum was about the impact of a lifestyle on the lighting design and also scrutinized what lighting atmosphere is characteristic of a European city and if it is the same for a Chinese, American, Arab or Indian. Maybe the answer lies in the fact that even natural light is different in different parts of the world and Professor Helena Gentili, architect, lighting designer and APIL member demonstrated this by showing the cultural differences in its use. In her conclusion she said, “Therefore, artificial lighting, as well, needs to be designed and controlled properly, according to people’s cultural and geographical references. Ms. Gentili went on to explain what lighting designers expect from LED manufacturers, luminaire manufacturers, importers and resellers. The other contributors to this forum addressed equally important aspects in various fields that need to be heard by manufacturers and the technicians that design the products.

The topic of spectrally tunable LEDs and OLEDs was organized by HiLED. It was split into three application fields: Human centric lighting, Horticulture and Museum Lighting. Whilethe horticulture session covered similar topics to the EPIC workshop; the other two subjects were concerned with visible light quality and all related aspects. A good part also covered the risks of LED lighting, especially blue light for humans and art. In this context it is important to notice that the impression that LED lighting is more critical than traditional light sources is misleading. Both the general and consumer press often misinterprets research results. The truth is that traditional light sources could be worse than high quality LED light and LEDs provide the opportunity to tune the spectrum to reduce risks. The presented research indicates that correctly applied LED lighting can be beneficial to health and well-being. In the case of shift work, which has always negative effects on people, spectrally tuned LED light can reduce the effects without compromising visual behavior like stimulation and cognitive abilities. The influence of light on the body clock, alertness and sleep was explained by Prof. Christian Cajochen who is LED professional’s interlocutor for the Tech Talk Bregenz in this issue. In the session about museum lighting applications, a comprehensive study about modern and traditional pigments, different binding material and varnish was discussed. The presenters pointed out that LED light spectra can be optimized for the perfect appearance of artworks from different periods by keeping the damage index lower than traditional light sources.

Horticulture lighting is becoming increasingly important. More workshops and lectures than ever before concern this topic at lighting conferences all over the world with some conferences being solely about horticulture. This year EPIC organized a horticulture workshop in Bregenz and the interest was enormous. The Association for Vertical Farming explained why this topic is of such high interest and what the benefits are. They said that it is expected that in the year 2050 over 80% of the 10 billion people on Earth will be living in cities. Currently 80% of freshwater is used for agriculture. Vertical farming needs up to 98% less water, reduces transportation effort and land use. Furthermore, it promises fresher food without the use of pesticides and without heavy metal contamination. Under controlled conditions, uniform quality and yield, 2-3 times higher growth rates and vitamin and mineral content are expected. Besides the CO₂ level, light is the most important key factor for this method to cultivate plants. A big part of the workshop concerned spectral tuning for plants. It was demonstrated how different spectra can change the growth and morphology of one species, resulting in compact, bushy plants with many leaves to long-branched plants with less but bigger leaves, many or no flowers, and so on. It was also emphasized that there is not one spectrum for all plants. Finally, solutions for these different requirements were presented and discussed: Single die LEDs, flexible configurable multi die LEDs, and controls for this task.

Workshops and forums covered topics like horticulture, IoT and light quality

The number of contributions and the variety in Jakajima’s workshop about IoT and AI underlines the statement of Dipl. Ing. Christian Anselmi from Antevorte - Innovation in Motion: “There is not one IoT networking solution for all”. The workshop substantiated this statement by presenting a selection of solutions for different applications based on different technologies. The experts covered the following topics: LoRaWAN as a long area communication approach and Cisco’s Smart+Connected Lighting system for outdoor applications, the digitalLicht concept for residential and hospitality applications, Adaptiva’s wireless sensor intelligent sensor networks for environmental monitoring tasks, and ChessWise’s self-organizing MyraMesh technology based networks as a highly sophisticated new solution for resilient communication, fostering the idea of building a stand-alone mesh network first and then to use the internet only if necessary.

SSL measurement seems to be a never ending story. New regulations and standards are necessary to take the properties of this light source into account, and some have become effective over the last few years. While uncertainties with how to deal with the results were an issue before, TÜV Süd and Instrument Systems concentrated on educating the attendees on the important topics of the required equipment and how to measure correctly. The workshop covered the basics of colorimetry and spectral quantities for LEDs as well as measurement equipment and their application. The introduction to the new standards and impact on labeling and the resulting requirements, safety aspects and eco regulations were also addressed. Practical questions like interference between a PWM driven product and integration time; which data must be reported from color tunable products; or, effects of the product housing color on measurement results were gone into.

The Expo: Product Launches and Innovative Start-Up Companies

For the second year in a row, companies with product launches at the LpS could take advantage of special promotion opportunities. Even though the Light + Building tied up many resources this year, approximately 10% of the exhibitors came to the LpS with a product launch. The new opportunity for start-up companies to show their products was readily taken advantage of and visitors appreciated the innovative approaches presented.

Product launches were promoted during the press conference and the show

Although a preview of the product launches was published in LpR 57 there is a lot more to say than about them: The features and improvements of Dow Corning’s two new products were noticeable when looking at the product samples they brought with them. The MS-4002 Moldable Silicone has an unusual appearance and provides a higher subjective quality of transparency. It gives the products a plastic-like, smooth surface, look and feel. Furthermore, this material’s curing speed is optimized for the injection molding process for liquid silicone rubber, enabling the production of optics with comparatively high hardness and low surface friction. Its high light transmittance with low attenuation coefficient, combined with a high Abbe number, enables lighting companies to design optics for luminaires with high lumen efficiency. High thermal stability ensures the retaining of high transparency - even in harsh environments. The advantages that Dow Corning attributes to the IA-1200 Adhesive are not that easy to reproduce as they are concerned with more manufacturing and speeding up the process. Auer Lighting’s new modular approach to replace and upgrade conventional CMH and CDM installations to SSL technology incorporates a color mixing technology that allows a color uniformity of 4 MacAdam ellipses for an 18° spot with a red-white LED module. Flip Chip Opto’s unique high power 100 W and 200 W UV flip chip COBs for industrial applications were the technical highlight of the company while their powerful visible light products were probably more attractive to most visitors. Gigahertz Optics introduced a new product designed for LED binning tasks, the TPI21-TH. Electronic zero setting, support for fully-automated measurement sequences, and use outside of dark rooms are just some of its remarkable features. Ophir Optronics FluxGage is intended to replace integrating spheres in automated measurement and testing systems for directional lights. The concept is based on solar cells in combination with an additional spectrometer for the color measurements and a fast photodetector for the flicker measurement. iLumTech’s innovative, intelligent, and dynamic smart city control and monitoring system, Synapse, presents the IoT trend and is built around the open LoRaWAN™ specification. Plessey introduced the OrionTM PLWSC3000 LED module based on their innovative StellarTM Beam Forming Optics (more about the concept and technology can be read on page 60). UL introduced further details and an update to their new flicker measurement, certification and labelling service. Not officially filed in time for the product launch and therefore not taking full advantage of the promotion opportunities, some other companies also showed new products for the first time at the LpS. For instance GL OptIc presented an updated version of their GL Spectis 1.0 FLICKER that now offers flicker measurement, and Fraen extended their range of Multi-TIR Nested Lenses for domeless LEDs.

Although Kyocera didn’t have a product launch, they exhibited for the first time at LpS, and showed their white LEDs. The technology might not look special at the first glance; they use purple or close to UV LEDs with a mix of multiple phosphors like others do. However, Kyocera is one of the few companies that make their own phosphor blends in combination with this technology to match natural sunlight as closely as possible to provide high quality white light.

Many companies, but especially the start-ups showed innovative products

The start-up section of the exhibition caught almost more attention from the visitors than some of the established companies. The innovative ideas and product designs were generally welcomed and perceived as an enhancement to the show. Carpet Light (we already reported from the Light + Building) came with the latest improvements and disclosed their roadmap for the next year. The manufacturing process has been approved now to allow the production of larger formats. One of the first 4’x4’ samples was presented here. While the CCT tunable product was originally designed for TV and movie applications, the company meanwhile also sees increased interest from the general lighting market. Another interesting concept was on display from Luke Roberts. The intelligent luminaire for human centric lighting is highly adaptive. Areas can be individually dimmed, color temperature can be adapted and the color of the indirect light element can be varied. The luminaire, which can be controlled by using a nicely designed and easy to handle app, learns from the user behavior, taking several parameters into account. Der Lichtpeter caused a stir, not only at his booth but also at his lecture. He presented his flicker measurement services and results and promoted his flicker metrics that significantly differs from current standards. He takes into account higher flicker frequencies, a subject discussed in our magazine several times. His loading of different frequencies also differs from the common standards. This is a topic that LED professional will keep an eye on. Two absolute highlights in the electronics domain belong to the start-ups too. Nordic Power Converters is one of these companies. The company’s technology has enabled this change by combining circuits from the RF industry with the design methodology of power electronics. These topologies eliminate the switching losses that limit the switching frequency of traditional SMPS’s. High-frequency power converters use significantly smaller energy storage elements, thereby eliminating the use of the most unreliable electrical components such as electrolytic capacitors if required. Representatives from different well-known lighting companies showed great interest in these products. The second company, AccurIC, could also drew a lot of attention with their linear current drivers. The drivers are based on new (patent pending) technology, enabling high-accuracy constant current regulation at levels required by high-brightness LEDs and LED chains. Through the use of a completely linear regulation method, these true constant current drivers eliminate the problems associated with switch-mode noise and ripple.

Products were presented and technologies explained in detail throughout the exhibition

The press conference ended with a Q&A session with international lighting experts including Professor Nakamura, Ms. Ling Wu, Carlos Lee, Heinz Seyringer, and Arno Grabher-Meyer

Accompanying Program: Art and Networking

For the first time, the opening ceremony with Prof. Nakamura was open to visitors and attendees, alike. Afterwards, Vorarlberg’s State Governor, Mag. Karlheinz Ruedisser, opened the reception, which was the perfect starting point for checking out the exhibition and networking. The Get Together Evening on Lake Constance, another great place to network, has become a tradition that nobody wants to miss. This is where people got the chance to talk with speakers and leaders of organizations or companies in a relaxed atmosphere. Munich Re, following their informative talk on “Risk Transfer and Investment for the LED Industry Forum” offered another networking event.

In addition to the traditional cruise around Lake Constance, the Munich Re event was another great opportunity to network

Clint Eccher’s impressive “Tiered Paintings” (LED professional published details of the painting technique in LpR 57) were shown in the Showroom at the Festspielhaus. Visitors, attendees and specialists were all equally amazed by these unique works of art. To pay homage to the location, this talented artist created a painting he named, “Bregenz 6000 years ago”. The image transforms from the ancient stilt houses to the lake stage of the Festspielhaus with changing LED illumination.

The showroom near the entrance of the Festspielhaus was a great place to relax while checking out Clint Eccher’s Tiered Paintings and the EL-foil that was entered into the Guinnes Book of World Records

Summary of the Impressions

The topics of the lectures as well as the promoted products in the exhibition show the continuation of the trends from Light + Building. The lighting industry is pushing IoT in hopes of getting their share of the pie. The activities in this direction could definitely lead to a success. Both lectures and exhibition indicate a clear commitment to high quality products and substantiate the fact that light quality and illumination quality will be the major topics in the coming years. This is also recognized as the basis for true, human centric lighting, another area that promises the European lighting industry good business opportunities. It is also encouraging to see that new ideas are still being generated that could further enhance light quality or lower costs. It is especially exciting to see how small companies and/or start-up companies are able to bring new and interesting concepts to the market. Once again, LpS was the perfect platform for presenting new ideas that foster the spirit of innovation.