By Laura Eley, Crossey Engineering
OLEDs – Lighting’s New WaveBuildings lighting
Organic light-emitting diodes could transform the lighting of spaces, with their flexible, thin surfaces that can be wrapped around different forms.
From the August-September 2015 print and digital edition, page 51.
We need look no further than the past decade to understand how rapidly lighting technology has evolved. While LEDs have quickly become the leaders in sustainability and application, a new lighting technology that offers just as much promise is on the horizon.
Organic light-emitting diodes, more commonly known as OLEDs, are a light source consisting of an OLED-stack — layers of organic materials sandwiched between an anode and cathode. The organic materials are derived from carbon-based compounds found in organic chemistry.
Initially discovered in 1950, and developed through the later discovery of highly conductive polymers, the first working OLED was developed in 1987. The first qualified OLED lighting component was released in 2009. Although OLEDs are now being marketed globally and displayed at lighting fairs, most manufacturers are based in Europe and South Asia. There are currently no major OLED manufacturers in Canada.
Thin and flexible, OLED fixtures illuminate a flat surface that can be extended and wrapped over areas large and small. They can be used for various purposes that include general and display lighting. Like LEDs, they use drivers to change AC to DC and regulate the current, are conventionally wired, and do not require ballasts.
OLED lights share a similar mean lifespan to LEDs at approximately 30,000 to 50,000 hours.
Most OLEDs today are used for decorative purposes such as accent lights, wall sconces and theatrical chandeliers, but experts predict that as the technology develops, it will become increasingly common and used for more functional purposes, including as general lighting in residential and commercial buildings.
“The uses and applications of OLEDs in the future will be limited only by people’s imaginations,” says Wallace G. Eley, P. Eng., chair of the board at Crossey Engineering in Toronto. “An analogy is something like the thickness of a piece of Bristol board being the light fixture in your ceiling. Or can you envision your conventional tabletop lamp which has a lamp and shade, in the future as a shade with no lamp? The shade, which will be the OLED, will be the light element because it’s luminescent.”
OLEDs will greatly reduce the space required for lighting installations due to their thin size and flexibility, while providing uniform illumination with no shadow or glare.
Unlike LEDs …
“People think that it [OLED] is the next step of the LED technology, but these are two completely different light sources,” explains Amir Sharabianloo of OSRAM Sylvania. “The difference is that with point source [LED], you’re going to have a lot of glare issues,” he says. “It could be blinding if you’re looking directly into your light source or a lamp.” Because it’s an area source and spread over a wider surface, OLED technology is more effective at minimizing glare.
Available in all colours including high quality white, OLEDs emit the same apparent radiance when viewed from various angles. In an off-state they can appear as transparent or mirrored. Flexibility, another unique feature of OLED devices, makes it possible to incorporate bendable light sources directly into designs. These details create multiple opportunities for commercial, residential, and even automotive lighting applications.
“A major lighting company is currently working on a concept where you can put the whole OLED panel in your window and your window acts as your light source,” explains Sharabianloo. “When it’s in an off-state, you can actually look through your window, (your light source), and then when you turn on the light source it will just glow inside.”
Sustainability is another attractive component of the OLED source.
Unlike LEDs, OLEDs produce very little heat and require less material during the manufacturing process. The source is also very durable and will last much longer than traditional lighting technologies, some of which require toxic materials during production — fluorescent lighting being one example as it requires a small amount of mercury to operate.
Although OLED technology holds great potential, challenges still remain. “The biggest challenge is the cost,” says Sharabianloo. The source’s energy efficiency also lags behind LEDs. “From the perspective of efficacy, OLED technology is where LEDs were 15 years ago.”
The manufacturing process is another consideration, as the organic materials that make-up the OLEDs are very sensitive to humidity and oxygen. “If a small molecule of oxygen or water gets into the panel, it could create black dots and seriously damage the panel,” Sharabianloo says. Due to these factors, it’s critical that the product is completely sealed-off during the manufacturing process, which adds to the complexity and cost of production.
Still, the outlook is hopeful. Says Eley: “There are some technical issues that need to be resolved, and will be resolved over the next few years, just as the technical issues for LEDs were resolved.”
Investment the largest obstacle
Both Sharabianloo and Eley expect OLEDs will make a global impact. Currently, the largest obstacle blocking the progress of OLED technology is a lack of funding. Increased investment in the technology will lead to improved performance and efficacy. Meanwhile, educating specifiers and end users about the technology’s possibilities will facilitate acceptance of these new light sources.
Says Sharabianloo, “If we provide the education, people will use them, and as they adopt more [OLEDs], the cost will come down.” cce
Laura Eley is a writer for Crossey Engineering, a multi-disciplinary consulting engineering firm with headquarters in Toronto.