After years of Development, OLEDs are poised to transform lighting design.
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Jamie Hankin/courtesy Blackbody
The I.Rain fixture, designed by Thierry Gaugain, descends from the ceiling of the new Blackbody showroom in New York, the first OLED store in the world. The company’s founders, Bruno Dussert-Vidalet and Alessandro Dolcetta, put together a team of 13 engineers and researchers devoted to advancing OLED technology.
"How have we always thought about a light ﬁxture?” asks Peter Ngai, vice president of research and development at Acuity Brands Lighting. “You make something hot and bright, and you put it on the ceiling. When we screw in a light bulb, the ﬁrst thing we do is ﬁnd a shade. Why? You have to diffuse the light, and maybe you have to ﬁgure out how to get rid of the extra heat.”
Ngai says that somewhat primitive approach could soon change radically. The reason? Organic light-emitting diodes, or OLEDs: Think of them as a two-dimensional light surface, rather than a directional light source. OLEDs emit light from a layer of electroluminescent material that is just a few nanometers thick (200 times smaller than a human hair). Unlike the classic hot, bright ceiling ﬁxtures of the past, they discharge light already diffuse and low-heat. This allows them to be ﬂat, lightweight, and ﬂexible; and, depending on the top layer and substrate material, they can also be transparent. “Instead of a point source, it’s an area source,” says Ngai, who runs the Acuity Lab in Berkeley, California. “It emits light over a large surface—say, two by two inches, or eight by eight inches.” Taken together, all these properties have profound implications for architectural lighting.
OLEDs aren’t new. They were developed in 1978 at the Eastman Kodak Company, based on a phenomenon called electroluminescence, which was discovered in the 1950s. (LEDs are based on slightly older research; the ﬁrst LED was created in Russia in 1927.) OLEDs create light by applying voltage to an organic (carbon-containing) compound sandwiched between a substrate and a transparent top layer. So, why is this technology poised to break out now? First of all, manufacturing techniques are improving, making cost-effectiveness an attainable goal. Thinner and more ﬂexible substrates recently have been developed. A technique called thin-ﬁlm encapsulation will further reduce thickness, allowing for lowered manufacturing costs and greater ﬂexibility. Transparent electrode materials could make it possible for OLED tiles to serve as both windows and light ﬁxtures. And with their diffused illumination, they’re also suitable for larger areas. The result is a new type of ﬂat light source that’s fundamentally different from anything before it.
Sources: http://electronics.howstuffworks.com/oled1.htm, http://electronics.howstuffworks.com/oled2.htm
OLEDs share a lot of the advantages that made LED lighting, which had its ﬁrst commercial application in 1968, so exciting. LEDs consume far less power and generate less heat than incandescent lighting, and don’t contain toxic substances like ﬂuorescents do. But while an LED, depending on lumens, can get very hot, OLEDs are low-heat and can emanate low-intensity light from a larger area. LEDs, which not too long ago looked poised to take over lighting, are slowly losing their edge, and are in danger of becoming outmoded. “LED has greater energy efﬁciency mainly because it’s a more mature technology,” Ngai explains. “But OLED technology is catching up. In three years, the difference will be relatively small.”
OLEDs are already widely used for screens and displays, an application that has contributed to the reﬁnement of their other strengths: small size and ﬂexibility. The extremely thin light-emitting layer adds to their vast design potential. Nancy Clanton, founder and president of Clanton and Associates, says past development work on LEDs will help OLEDs progress faster, since some advances apply to both technologies, adding, “The organics have way surpassed where LEDs were at this point in their development.” For years after they were ﬁrst introduced, she recalls, LEDs were inefﬁcient and expensive. “It’s like any new technology; it’s going to start with tiny baby steps.”