Thursday, December 18, 2008

Next generation Smart LED lighting

Next generation Smart LED lighting

When I was growing up, Dufferin Street in Toronto was lined with factories producing incandescent light bulbs by GE. Those factories are long abandoned or turned into lofts or condos.

The city and the federal government should be looking at attracting the next wave of lighting manufacturers ie the ones that will be producing smarter lighting with light emitting diodes (LED) and organic light emitting diode (OLED) systems. Consumers are already getting their first taste of LED technology...those outdoor solar-powered Christmas lights

The figure above comparses the luminous efficacy (source efficacy) of conventional lighting technologies with the potential of light-emitting diode technology. (N.B. Log scale)

If all the world was to switch over to LED there would be a tremendous savings in energy costs and an increase in energy security ( 280 fewer power plants on the globe and billions of barrels of oils)

Researchers conclude:

"LEDs are more rugged, resembling something closer to hard plastic than thin glass. They are also more environmentally sound, since their manufacture does not require toxic substances such as mercury.

As an alternative to the traditional incandescent light bulb, LED lights provide significant energy savings. They can be 2,000 percent more efficient than conventional light bulbs and 500 percent more efficient than compact fluorescent bulbs. Engineers and scientists predict that widespread use of LEDs over the course of 10 years would save more than $1 trillion in energy costs, eliminate the need for nearly a billion barrels of oil over 10 years, and lead to a substantial reduction in emissions of carbon dioxide, the most common greenhouse gas. "

Smart LED's should not be seen as just a replacment technology for compact fluorescent lamps (CFL's) and Incandescent lamps but as a serious disruptive technology. Regular bulbs can only be turned on or off, where as LED's can be tuned like a radio. LEDs have novel capabilities that make them extremely useful when going beyond the replacement paradigm. In contrast to conventional light sources, a number of new dimensions are opened up by the unique controllability of LEDs. These include control over the emission spectrum, color temperature, polarization, temporal modulation, hue and spatial emission pattern. These controllable LED sources, called smart lighting sources will result in tremendous benefits to society and humankind, including:

· Biology and imaging: Leapfrog advances in quantitative biology, particularly the rapid identification and counting of biological cells through adaptive and fully tunable reflectance and fluorescence imaging.

· Display systems: Liquid-crystal-displays and projectors with unprecedented efficiency and brilliancy (huge color gamut) through polarization-controlled lighting sources.

· Transportation: Enhanced visibility (less glare) and safety through polarization controlled headlights, temporal-controlled communicating headlights/brake lights/traffic lights, and interactive roadways.

· Communications: Fundamentally new modes of broadcasting, communications, and sensing through temporal control of solid-state-light sources.

· Human factors: Reduced dependency on sleep-inducing pharmaceuticals, higher productivity, prevention of certain cancers, and higher quality of life.

· Agriculture: Efficient plant growth in non-native regions (including space) and non-native seasons. Revolutionize indoor agriculture and Urban indoor Vertical Farming or skyfarming

Source: "Transcending the Replacement Paradigm of Solid-State Lighting," E. Fred Schubert and Jong Kyu Kim, Optics Express, Vol. 16, Issue 6, December 22, 2008, Focus Issue on Solar Energy


The field of photonics starts with the efficient generation of light. The generation of efficient yet highly controllable light can indeed be accomplished with light-emitting diodes (LEDs), which are, in principle, capable of generating white light with a 20 times greater efficiency than conventional light bulbs. Deployed on a global scale to replace conventional sources, such solid-state light sources will result in enormous benefits that, over a period of 10 years, include (1) gigantic energy savings of 1.9 x 10*20 joule, (2) a very substantial reduction in global-warming CO2 emissions, (3) a strong reduction in the emission of pollutants such as acid-rain-causing SO2, mercury (Hg), and uranium (U), and (4) financial savings exceeding a trillion (10*12) US$. These benefits can be accomplished by the “replacement paradigm” in which conventional light sources are replaced by more energy efficient, more durable, and non-toxic light sources. However, it will be shown that solid-state light sources can go beyond the replacement paradigm, by providing new capabilities including the control of spectrum, color temperature, polarization, temporal modulation, and spatial emission pattern. We will show that such future, “smart” light sources, can harness the huge potential of LEDs by offering multi-dimensional controllability that will enhance the functionality and performance of light sources in a wide range of applications. These applications include optical microscopy, imaging, display technologies, communications, networking, and transportation systems.