The Consumer Electronics Show (CES) in Las Vegas seems an unlikely spot to find a product touted to revolutionize architectural lighting, but this January, a see-through, organic light-emitting diode (OLED) computer screen could be found among the gadget geeks and showgirls. Just millimeters thin and capable of emitting a full-color spectrum, the OLED is perfect for displays and is rapidly finding its way into commercial use: laptops, televisions, cell phones, and PDAs. Yet Samsung’s transparent 14-inch prototype screen at CES 2010 offers something beyond consumer electronics, pointing to new ways of making architecture.
Imagine that transparent OLED as a window—or, for that matter, a wall. With the flip of a switch, the semiconductors fire, and the clear panel transforms into a screen or a light source. “Instead of the environment having to accept the lighting, the lighting fits into the environment,” notes Barry Young, managing director of the OLED Association, an industry trade group. Adds Dietrich Bertram, Philips Lighting’s OLED technical officer: “[OLEDs] could change how we experience light and architecture.” While full integration into building materials is still several years away (Bertram predicts five to eight years), manufacturers—including Philips, General Electric, Panasonic, Osram, and Samsung—are gamely pursuing the possibilities.
Unlike a standard LED, which emits light from a single point, an OLED is a diffuse-area light. Organic, electroluminescent film is sandwiched between a negatively charged layer of aluminum and a positively charged layer of indium tin oxide, all of which is housed between sheets of glass or plastic. (“Organic” refers to the fact that the film is made up of compounds whose molecules contain carbon.) When a voltage is applied, the film acts as a semiconductor and glows.
In terms of efficiency, today’s OLEDs are roughly 25 lumens per watt (lm/W), only slightly better than traditional lamps (incandescents average 17 lm/W, and tungsten halogen reflectors average 14 lm/W), but they still need development to match fluorescents (T5: 104 lm/W; T8: 88 lm/W), a source with one of the greatest luminous efficacies on the market.
Although high production costs have challenged manufacturers’ ability to bring products to market, Osram Opto Semiconductors introduced the Orbeos panel in late 2009. Octagonal in shape, with a 3-inch-diameter lamp surface, the fixture is the company’s first truly commercial OLED product. Only 2.1 mm thick, the Orbeos can be installed like a tile, with the lamps fitting together to cover a large surface. The panel has a warm color temperature equivalent to an incandescent bulb, but because the light source is diffuse, the Orbeos is atmospheric and essentially glare-free.
Philips began researching OLEDs for displays in the 1990s—it now offers a number of consumer products with OLED screens—and embarked on lighting a decade later. The company’s most recent development is the Lumiblade, a discrete lighting component that premiered at the 2009 Salone Internazionale del Mobile and is now available in several shapes and sizes. This winter, the company installed a Lumiblade sculpture at the International Design Museum Munich. Designed by rAndom International, You Fade to Light uses 900 rectangular modules to create an interactive mirrored wall, in which a viewer’s movements are translated into movements across the array. Osram has also paired with a designer: In 2008, in conjunction with Ingo Maurer, it launched Early Future, a limited-edition, commercially available table lamp featuring 10 OLED modules that sprouted, leaflike, from a tilted stand.
Brian Terao, Osram’s director of solid-state lighting, predicts higher, more compatible outputs in the near future, so that OLEDs can effectively compete as sustainable products. There is even hope that the technology can be used as a power source, says the OLED Association’s Young. “OLEDs operate by converting electrical energy into light, but if you think about reversing that, you can convert light to energy,” he notes—and research by Cornell University and other institutions has shown this is more than just speculation.
Looking ahead, manufacturers are searching for ways to take advantage of the physical properties of OLEDs. Spread the electroluminescent film between two malleable plastic sheets, and the lamp is flexible. At the moment, the printing process that bonds the film to plastic determines the size of each OLED module, but GE is currently working on how to print on large rolls, much like a newspaper press. Terao sees OLED technology integrated into ceiling troffers in the workplace or engineered into a medium capable of being painted directly onto any surface to which a charge can be applied. Fantastic as it seems now, once the lab techs work out how to stabilize the film, just flip a switch, and the architecture is illuminated.