Shedding light on organic LEDs

Energy Efficiency

Light emitting diode bulbs, with their minuscule energy consumption and 20-year life expectancy, have grabbed the consumer’s imagination. But an even newer technology is intriguing the world’s lighting designers: Organic light-emitting diodes, create long-lasting, highly efficient illumination in a wide range of colours, just like their inorganic LED cousins. The emissive electroluminescent layer in an OLED is composed of a film of organic compounds.

But unlike LEDs, which provide points of light like standard incandescent bulbs, OLEDs create uniform, diffuse light across ultrathin sheets of material that eventually can even be made to be flexible. Ingo Maurer, who has designed chandeliers of shattered plates and light bulbs with bird wings, is using 10 OLED panels in a table lamp in the shape of a tree. The first of its kind, it sells for about $10,000.

He is thinking of other uses. “If you make a wall divider with OLED panels, it can be extremely decorative. I would combine it with point light sources,” he said. Other designers have thought about putting them in ceiling tiles or in Venetian blinds, so after dusk, a room looks as if sunshine is still streaming in.

Used in cell phones
Today, OLEDs are used in a few cell phones too. The organic LED displays produce a high-resolution picture with wider viewing angles than LCD screens. In 2008, seven million of the one billion cell phones sold worldwide used OLED screens, according to Jennifer Colegrove, a DisplaySearch analyst. She predicts that next year that number will jump more than sevenfold, to 50 million phones.

But OLED lighting may be the most promising market. Within a year, manufacturers expect to sell the first OLED sheets that one day will illuminate large residential and commercial spaces. Eventually, they will be as energy-efficient and long-lasting as LED bulbs, they say.

Because of the diffuse, even light that OLEDs emit, they will supplement, rather than replace other energy-efficient technologies, like LED, compact fluorescent and advanced incandescent bulbs that create light from a single small point.

Its use may be limited at first, according to designers, and not just because of its high price. “OLED lighting is even and monotonous,” said Maurer, a lighting designer with studios in Munich and New York. “It has no drama; it misses the spiritual side.”

“OLED lighting is almost unreal,” said Hannes Koch, a founder of rAndom International in London, a product design firm. “It will change the quality of light in public and private spaces.”

Because OLED panels could be so flexible, lighting companies are imagining sheets of lighting material wrapped around columns. Organic LEDs can also be incorporated into glass windows; nearly transparent when the light is off, the glass would become opaque when illuminated.

Because OLED panels are just 0.07 inches thick and give off virtually no heat when lit, one day architects will no longer need to leave space in ceilings for deep lighting fixtures, just as homeowners do not need a deep armoire for their television now that flat-panel TVs are the norm.

There are firms developing a roll-to-roll manufacturing process, similar to the way photo film and food packaging is created; it expects to offer OLED lighting sheets as early as the end of next year.

“We think that a flexible product is the way to go,” said Anil Duggal, head of GE’s 30-person OLED development team. Organic LED is one of the company’s top research priorities; the company is spending more than half its research and development budget for lighting on OLED.

Exploiting the flexible nature of OLED technology, Universal Display has developed prototype displays for the U S military, including a pen with a built-in screen that can roll in and out of the barrel.

As production increases and the price inevitably drops, OLED will eventually find wider use, its proponents believe, in cars, homes and businesses. “I want to get the price down to $6 for an OLED device that gives off the same amount of light as a standard 60-watt bulb,” said Duggal. “Then, we’ll be competitive.”

NYT News Service