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Illumination that thinks: the potential for 'smart lighting'

The potential for solid-state lighting to save huge amounts of energy comes not just from the inherent efficiency of LEDs compared to incandescent bulbs, but also from smart methods of illumination control. Professor Robert Karlicek, director of the Smart Lighting Engineering Research Center headquartered at Rensselaer Polytechnic Institute in Troy, NY, will speak on the subject of ‘smart lighting’ at the Optical Society’s Solid State and Organic Lighting conference in Tucson Arizona at the beginning of November. Here he gives a summary of his presentation:

Very efficient white LED bulbs are replacing inefficient incandescent bulbs. While there are many technical and market challenges to sort out, it is becoming clear that new capabilities and functionality beyond simple bulb/socket lighting systems will become the future of solid-state lighting (SSL). While LED replacement bulbs will be the first wave of solid-state lighting, digitally controlled full-gamut light sources that integrate high performance light sensors and new control and communication methods will create the second wave of solid-state lighting, or ‘smart lighting’.

Smart lighting systems are comprised of illumination technologies that use the spectral and temporal capabilities of LED technology to provide light, automatically adapt colour and intensity to changing illumination requirements, and provide enhanced services beyond simple illumination. The key will be the development of lighting systems that can ‘see’ and ‘think’, providing exactly the right light where and when it is needed.

One example is sensory lighting systems in the workplace or in healthcare facilities, where spectral tunability and high speed LED switching capability, combined with networks of advanced sensors and adaptive lighting communications and control architectures allow the illumination to be adapted to the needs of the occupants. New features will enable improved lighting system energy efficiency as well as improved human health and productivity. Future illumination systems will feature both intra-system (light-to-light) optical communications and data communications that will augment RF based communications systems for scalable, secure wireless communications [1]. In addition, digitally modulated (and structured) lighting offers novel approaches to occupancy sensing (of both animate and inanimate objects) [2]. By improving the sensory functionality of illumination systems, adaptive lighting control methods superior to the current lighting management methods in use today will be possible.

In addition to the use of modulated light, spectral management of illumination offers potential benefits in efficacy as well as benefits in human factor considerations like circadian management and worker productivity [3]. SSL developers are just starting to explore this potential. Developing the spectral tunability of solid-state lighting will require additional advances in materials, devices and control systems, as well as a better understanding of how lighting spectral content impacts human psycho-physiological well being. The addition of colour gamut to simple white colour rendering capability of conventional sources are driving a re-examination of basic architectural and human factor considerations in illumination design.

Finally, the integration of SSL and video display systems pose some interesting possibilities as lighting systems look to offer functions like virtual skylights, windows and video – illumination interchangeability [4]. To a degree, this association is natural, and almost every video display company already has an associated solid-state lighting business unit. While the fusion of illumination and video functionality stretches the boundary of what might be considered for the future of solid-state lighting system design, these types of systems are already being explored in development labs.

The long lifetime of SSL systems will challenge the century-old business models supporting conventional lighting markets and businesses. While there are still issues with colour stability and driver reliability that need to be overcome, SSL lifetimes exceeding 70 kHrs or more should become commonplace in the near future, eliminating the need for sockets in new lighting installations. With the expectation that the implementation of first wave SSL will have a profound impact on sales revenues from traditional bulbs and sockets, lighting companies must develop and deliver a host of new services and features to stay in business. New smart lighting systems will be designed to take full advantage of the properties of digital light sources, advanced light sensors, and control and communication architectures based on light.

Smart lighting will create new, immersive lighting environments that maximise energy savings and illumination quality while integrating communications and video services. Just as early transistor developers did not envision the full range of capabilities that would be enabled by their work, solid-state lighting developers are setting the foundation for a wide range of new capabilities and services that are only starting to be imagined.

References

[1] A.M. Vegni and T.D.C. Little, Handover in VLC Systems with Cooperating Mobile Devices, Proc. Mobility and Communication for Cooperation and Coordination (MC3) Workshop, IEEE Intl. Conference on Computing, Networking and Comm., (ICNC 2012), Jan. 2012.

[2] L. Jia and R.J. Radke, Using Time-of-Flight Measurements for Privacy-Preserving Tracking in a Smart Room., IEEE Transactions on Industrial Informatics, appeared online 8 March 2013 http://dx.doi.org/10.1109/TII.2013.2251892

[3] J. A. Veitch, M. G. M. Stokkermans, G. R. Newshan, Linking Lighting Appraisals to Work Behaviors, Environment and Behavior, (2013) 45 (2) 198-214.

[4] Fraunhofer Press Release (2012) Sky Light Sky Bright – In the Office, www.fraunhofer.de/en/press/research-news/2012/january/sky-light-sky-bright.html Accessed 5 January 2012

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