Light-emitting diodes (LEDs) are increasingly common in lamps and lighting fixtures in a range of settings. They are even beginning to dominate in some applications, including high-wattage area and streetlights. With $5 Edison-style lamps now showing up on Home Depot shelves, an LED takeover of the lighting industry might seem to be an all-but-foregone conclusion. Not so fast, say a growing number of lighting experts. Organic LEDs (OLEDs) are following a similar fast-track path of development, and they are beginning to show up in new products addressing applications in which LEDs can fall short.

Defining the differences

OLEDs are similar to LEDs in a number of ways (but, no, they are not just regular LEDs produced without artificial fertilizers or pesticides). Both technologies use solid-state electronics to create light in the presence of an electrical charge. In LEDs, this process takes place on a computer chip, creating a single point source of illumination. In many unlit LED lamps and fixtures, you can see the individual chips.

With OLEDs, however, the charge is passed across a substrate that has been treated with organic (i.e., carbon-based) material to create a surface-wide (or “planar”) light source, an ideal qualification for ambient lighting. OLED fixtures are efficient and cool to the touch, and they don’t require heat sinks, so they can be much thinner than LED-based luminaires.

“We believe LEDs and OLEDs are complementary to each other,” said Mike Lu, director of innovation engineering, Acuity Brands’ OLED division. 

The point-source nature of LEDs provides an obvious application, he said, “the low-hanging fruit of the light bulb.”

This all can seem a bit deep in the weeds to folks used to fluorescent-based troffers and incandescent-based downlights, but understanding applications as opposed to commodity products is a new reality for lighting designers and electrical contractors alike. Driven by increasingly strict energy codes, along with outright elimination of the least-­efficient products from the marketplace, lighting installation planners are facing a new performance-based reality. Players in the OLED market say specifiers need to start paying attention to the technology’s ability to address ambient applications 
efficiently and creatively.

Light like no other

“[The OLED] offers a form factor like no other before, and the quality of light is better than anything out there that’s still efficient,” said Michael Helander, president and CEO of OTI Lumionics, a Toronto-based startup focused on developing OLED applications and products. 

The group recently launched a task lamp, the Aerelight, which takes advantage of the glare-free nature of OLED-
based illumination (Editor’s note: For a photo of the Aerelight, see Editor’s Eye on page 6).

“It’s not a tiny point source of light. When you have an area source, the way you design fixtures is completely different,” Herlander said.

While the Aerelight uses a single OLED panel, Acuity has begun developing multipanel products, first for high-end commercial applications with fixtures such as Trilia, which chains together large numbers of modules in designs that are as much sculpture as they are illumination sources. More recently, the company made a bold step into mass-market retail, with the launch of the Chalina pendant/flush-mount fixture and the Aedan pendant/sconce through Home Depot’s website and in select Home Depot stores.

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Company managers see value in getting more fixtures into the marketplace to give consumers the chance to experience lighting many consider to be different than anything they have seen before.

“What the designers say is that people literally want to touch the OLEDs,” said Jeannine Wang, director of Acuity’s OLED business. “OLED really does have something that’s unique to offer. I think it has something to do with the visual quality of the light emission.”

This kind of “seeding” is important, said Mike Hack, vice president of strategic product development and general manager, OLED Lighting & Custom Displays for Universal Display Corp., an OLED technology developer. Consumers need to see the fixtures in action to truly understand their value.

“What’s important to OLED lighting is seeing and experiencing it,” he said. “Everybody likes the incandescent bulb because the light it gives off is like sunlight,” a quality OLED lighting shares.

Hack sees that unique quality and the fixtures’ undeniable thinness helping OLEDs in the ceiling-mounted, area-lighting market, especially against LED-based edge-lit panels, which attempt to duplicate the glare-free ambient performance OLED backers promote.

“The color quality, the fact they don’t glare, you can’t get that with LEDs,” he said. 

To eliminate glare with LED edge-lit designs, manufacturers incorporate sophisticated lenses and bezels, which makes for better illumination, but comes at a cost.

“You can get very high-quality LEDs now,” Hack said, “but their efficiency drops.”

Acuity’s Lu agreed.

“The feeling is that, by trying to transfer LED into a planar source, you’re losing a lot of efficiency,” he said, noting the need for expensive optics and the added depth necessary to address heat-sink requirements. “We believe in the long-term, OLEDs will exceed LEDs in efficacy and in price.”

Manufacturing costs remain a hurdle

In the short term, however, OLED lighting has some hurdles to overcome. As with LEDs five or six years ago, manufacturing costs remain a challenge for developers. The technology has started to come to scale, thanks to the growing market for OLED displays for smartphones, tablets and flat-screen televisions. Such rectilinear roots could be one reason why products now appear to be modular assemblies of identical panels that are simply grouped and regrouped into different patterns.

“You want to limit the number of designs because you want to see what the luminaire manufacturers want,” Hack said, adding that, while 10 cm by 10 cm (4 inches by 4 inches) is a typical building-block size, “the industry doesn’t really have standards yet, and I think those will [develop] in the next few years.”

Developing the scale for more lighting-specific manufacturing processes also is important.

“The materials that are used for lighting and displays are basically the same,” Helander said. “Where there are differences is in the performance specifications,” because lighting doesn’t need the complicated patterning capabilities a display requires. For lighting, “you need something that, per unit area, is far, far brighter.”

One advantage OLED developers are beginning to exploit is the fact that the products can be, essentially, printed using roll-to-roll equipment. The substrate can be some form of plastic, or, as some manufacturers now are exploring, a material that sounds like an oxymoron: “bendable” glass. This means that OLEDs could create continuous bands of light that bend around corners and curves. This is an application auto­makers have begun to explore; both Audi and BMW showed OLED-equipped concept cars in this winter’s round of touring automobile shows.

“They want some unique shapes,” Hack said, noting signature design elements like tail and brake lights as an example. “The fact they can make [OLEDs] flex and curve them to the shape of the car is very interesting.”

Companion technologies

In the end, though it seems natural to pit LEDs and OLEDs against each other, these experts all agree it is short-sighted. After all, lighting designers have long had multiple tools to draw on when creating multipurpose lighting designs. So, fluorescent tubes became standard issue in many ambient settings in corridors and open-office areas, and incandescent halogens became the go-to option for spotlighting in retail and accent applications. Similarly, OLEDs and LEDs can be combined to create lighting designs that are equally attractive but with far greater efficiency and controllability than the technologies they are set to replace.

“In the long term, I think they are definitely complementary,” Helander said. “I think putting the two technologies together is going to give us the most efficient and aesthetically appealing lighting system.”