Second HI-LED workshop 2016
The second HI-LED workshop event would be held on Festspielhaus Bregenz, Austria, September 21st, 2016 co-colated during the LED professional symposium +Expo, LpS 2016 event. Thematic priorities in this workshop include the next topics: Museum lighting, Tunable lighting systems for biological rhythms adaptation and hormone balance, Solid State Lighting (SSL) for mood and cognitive performance and SSL for non visual pathways stimulation, horticulture lighting, Tuneable OLED lighting.
How does light affect people, plants and paintings?
For human health and performance, the HI-LED project is considering the effect of different light spectra on the suppression of melatonin (the “sleepiness” hormone), which is a measure for quantifying stimulating of the non-visual pathway, which originates in a special class of melanopsin-containing retinal cells discovered only in 2002
Illuminating the effects of light on people, plants and paintings
HI-LED is developing new light engines by optimising configurations of Light Emitting Diodes (LEDs) and by combining LEDs with Organic Light Emitting Diodes (OLEDs), and creating dynamically tuneable lamps.
Programme: Workshop Digital Light and human health
Lighting conditions affect to cognitive abilities and behaviours. Full control of spectral features of lighting enables the possibility of discriminating and individually exploiting such effects. SSL light-engines with added intelligence offer the possibility of tailoring spectral distributions respectful with our circadian rhythms or capable of inducing desired effects on behaviour, mood and/or physiology.
HI-LED workshop 2015
The HI-LED project is organizing the workshop on Human Centric Lighting: “Digital lighting and human health”. The date of this event is 18th June in the afternoon (15:00 pm to 19:00 pm), Barcelona, Spain, in the framework of the Barcelona Global Energy Challenge conference 2015.
Workshop HI-LED: "Digital lighting and human health"
Workshop Focus The HI-LED-2015 workshop event would be held on 18th June in Barcelona, Spain. This is a scientific meeting focused on human centric lighting supported by the FP7 Framework programme and hosted by Catalonia Institute for Energy Research Institute (IREC).
Daylighting, lighting and hybrid control solutions for Nearly Zero Energy buildings
The next 12th March, the FP7 HI-LED project will participate in the workshop "Daylighting, lighting and hybrid control solutions "
HI-LED project: Newsletter January 2015
Newsletter January 2015 "The role of LED lighting in greenhouse horticulture"
Greenhouse growers visit the HI-LED experiment
On 10 December 2014, Wageningen UR Greenhouse Horticulture and the Dutch Horticultural Growers Association organised a “Light Event” for the horticultural sector. Over 130 growers, extension workers and suppliers to the horticultural sector visited the HI-LED experiment, which was one of the demonstration trials.
The summer 2014 exhibition at the National Gallery (London), “Making Colour”
The interactive installation presented a short film introducing fundamental principles of how humans perceive colour, from the eye to brain. It was also the first anywhere to include a mass public experiment on colour perception under tuneable LED lighting.
Human centric lighting is intended to promote a person’s well-being, mood and health. It can improve concentration, safety and efficiency in workplaces or educational environments. It can support healing processes and prevention of chronic diseases among persons with irregular daily routines or in elder care.
In short, lighting is not just visual; it is now evident that lighting has biological and emotional impacts on human beings.
Human-centric Intelligent LED engines for the take up of SSL in Europe
The HI-LED project will advance the state of the art of Solid State Lighting (SSL) through research on innovative light engines that take advantage of full control of light. The incorporated intelligence enables responsive fine tuning of spectral properties in real time, as well as precise dimming capabilities.
These smart engines with added intelligence offer natural illumination patterns that respect our biological circadian rhythms. This can be done very accurately by spectral selection or even through Correlated Colour Temperature (CCT) adaptation by using the most efficient combination of white LEDs, coloured LEDs, and OLEDs as building blocks of the light source, while satisfying different constraints on energy efficiency.
Markets such as horticulture, greenhouses, light for human health would also benefit from fully controllable light engines, whose spectral content can be dynamically adapted in real time, through the establishment of algorithmic strategies and feed-back systems that control the processes and human response.
Additionally, these light engines are particularly well suited for museum lighting, where careful selection of spectral content may achieve an optimal balance between energy efficiency, quality of light and art conservation.
Solid-State Lighting (SSL) is now a mature technology that is rapidly climbing in share among the different commercial lighting technologies. The potential of getting high efficacies, colour quality, the utilization of non-contaminant materials and its positive life cycle analysis make this technology a clear choice for the future.
Currently LEDs can reach a luminous efficacy of 276 lm/W in a laboratory environment, and are predicted to reach 280–330 lm/W in the short term. However, the fact that SSL is approaching its theoretical roof on efficacy makes it necessary for research to focus on the rational use of energy through dedicated intelligent light engines governed by smart spaces, cities and societies.
The fact that SSL can be easily governed and integrated with ICT systems opens up promising lighting applications that can impact our society and our economy.
Different theoretical and real light spectra reproduced with currently available LED channels
The spectrum of light (power spectral density) is the full physical signature of any lighting process (aside from angular distribution of radiation that can be shaped with dedicated optics). Before the advent of SSL, it was only possible to have light sources provided with fixed spectrum, determined by the physical properties of the materials involved in the emission processes.
The HI-LED project will conduct research in new SSL proofs of concepts that strongly overlap with ICT (Information and Communication Technologies). In the EC Green Paper "Lighting the Future: Accelerating the deployment of innovative lighting technologies", it becomes clear that research in intelligent lighting systems can benefit the EU economy at large.
The final goal of the project is to conduct research on spectrally tuneable light engines with added intelligence, low-cost, low-consumption in connection to a broad and multidisciplinary team, deemed necessary to validate the results, final claims and impact in diverse applications. Multidisciplinary research offers the opportunity to open new areas of research, to use different expertises to explore the same issue, to tackle complex problems and to augment the return on investment in research of photonic technologies by opening the use of knowledge, tools, methodology and solutions generated in one discipline to other disciplines.
First general diagrammatic overview of the project
At present time, SSL technology offers a completely new paradigm associated with the possibility to mimic any light spectrum imaginable in the visible range (see examples provided in Figure 2). Spectral optimization gives rise to a full range of potential applications where specific spectral components are critical or play an important role, while at the same time allows control over energy efficacy by adapting those components to the parts where the particular application is more sensitive to.
The objectives of this project lie within the expected outcome of the Objective ICT-2013.3.2 Photonics, essentially in two different ways:
1 “Large-area, large uniformity OLEDs for general lighting applications with increased lifetime and brightness enabling an effective market introduction”:
In 1987, Tang et al, reported about a novel electroluminescent diode that is based on organic materials. Two organic thin films – an organic aluminium complex and diamine - were deposited onto a glass substrate with a conductive indium-tin-oxide (ITO) based surface. Afterwards the stack was coated with a magnesium cathode and contacted with about 10 V direct driving voltage. This was the first reported organic light emitting diode (OLED) showing a luminous efficiency of 1.5 lm/W and a brightness higher than 1000 cd/m² at 10 V driving voltage.
Since then OLEDs attracted rapidly increasing attention first in research and later in application due to their outstanding unique properties. In contrast to competing, state-of-the-art light source OLEDs allow
- Area-illumination on large-areas in contrast to spot light-sources [e.g.inorganic light emitting diodes (LED)].
- A flat light source design, as OLEDs are based on thin films with a thickness of a few micrometres or even less.
- Optical transparent light sources allowing “invisible” lamps, e.g. on glass surfaces such as windows.
- Flexible and bendable light-sources when the OLED layer stack is applied onto a flexible, e.g. polymer, substrate.
- Potential low-cost manufacturing due to the use of large-area sheet-to-sheet or roll-to-roll manufacturing process
- Low energy consumption and low heat generation with a high luminous efficacy (lumen per watt) reaching values of 100 lm/W in 2012 which are similar to commercial inorganic LEDs.
OLED material stacks will be designed in WP3 that are able to smoothly span the “green gap” (see figure below) that conventional LED technology cannot cover due to an extreme lack in efficiency. In this sense, a hybrid solution will be investigated so that continuity is guaranteed throughout all the energy ranges of interest for the different application WPs.
2 “High performance, reliable and low-cost SSL modules with added intelligence to provide optimal lighting solutions”:
Here, by optimal lighting solutions, not only the energy efficacy of the modules (and final luminaires) will be considered, but also the modules will be provided with added intelligence so that the spectral content can be timely adapted to applications with different spectral requirements. Functional lighting for several applications involving different degrees of sophistication will be investigated and validated through the presence in the consortium (WP4) of specialists in neuroscience (interactions between light and human brain), plant biology (light-plant interaction), and art lighting (high quality artwork illumination).
More concretely, the particular objectives to be achieved in this project are listed below:
- Specification, design and implementation of a lighting module with added intelligence able to mimic arbitrary light spectra in real time.
- Excellent thermal design to achieve negligible colour shifts with temperature. Colour shifts (precision) of less than ∆Euv < 0.0025 (see Figure 4) units between the projected and measured spectra should be achieved regardless of the junction temperature, with an accuracy of ∆Euv=0.0010.
Blackbody locus in the CIELUV U-V plane, showing a deviation range of ∆Euv=0.05 in 0.0025 steps, for different CCT values (2500K, 2700K, 3000K, 3500K, 4000K, 5000K, 5800K, 6500K, and 8000K)
- Excellent optical design with a balanced simplicity versus performance features, providing good colour mixing (with maximum colour difference with respect to the target white in the illumination pattern of 0.08, considering the 1976 CIELUV colour space) without compromising the luminance.
- The latter will be achieved by enhancing the light engine efficacy through a simple/optimized thermal scheme for the LEDs cooling (that will have to handle less than a third of the thermal load, compared to tightly packed chip arrays) and a reduced equivalent source etendue, and by the usage of high reflectivity (>95%) materials in the cavity.
- Develop a strategy involving top-emitting green OLED to meet the requirements of different specific applications and cover the green-gap in efficiency of LED technology, particularly in the region from 520 to 600 nm.
- Highest overall efficacy for the selected output spectral content, with an eco mode showing an efficacy of at least 120 lm/W for illumination applications and overall efficacies >35% in greenhouses. This objective should be achieved along with a demonstration of the following facts:
- a) Develop energy efficient lighting strategy for high yield of good quality horticultural products that enhance human health. This strategy will reduce energy use per unit greenhouse area by 20%, and at the same time increase production by 10% and double the vitamin C content of fruits. This strategy will be based on novel SSL technology with tuneable spectrum and intensity that can be controlled based upon monitoring of the efficiency of the SSL-plants systems.
- b) Demonstrate a light engine emitting selectable spectra of optimal duration, radiance and irradiance levels, and, most importantly, relative spectral content of illumination for maximising mood and cognitive performance, while minimising disruption to the sleep-wake cycle and potential retinotoxic effects.
- c) Demonstrate a light engine emitting selectable spectra optimized for different artefacts and artwork, by conducting research on the reflection spectra of real pigments used during the Centuries by artists.
- End up with a reliable optimization algorithm for spectral matching and other derived parameters (CCT, colour coordinates, Colour Rendering Index and other colour quality and spectral productivity indicators).
- Deliver a front-end interface that allows the non-expert user to easily communicate with the luminaires in a reliable manner, making it possible to easily select and program lighting spectra with different functionalities depending on the application.
- Achieve a wide dissemination of the project result in different media and at different levels, including social networks.