LEDs and OLEDs are often grouped together in industry discussions, but while the former has taken ahold of—and transformed—the lighting sector, the latter has followed a more gradual trajectory of development and adoption. Performance, life span, and cost have set the two lighting sources apart, but recent advances in OLED panel technology accompanied by successful field-testing have narrowed the gap.
The Basics
OLEDs, or organic light-emitting diodes, share a portion of their name with LEDs but that is where the similarities end. LEDs use two electrodes—a cathode and an anode—to produce and emit light and can be configured in linear or circular arrays as a component directly within the luminaire assembly. OLEDs sandwich organic compounds between the cathode and anode, which are then applied to a substrate that typically is rigid, such as glass. In recent years, OLED manufacturers have explored other substrates such as plastic, which enable flexible and curved OLED panels, as well as larger panel sizes and shapes beyond the conventional 2-inch-square or 4-inch-square format.
Perhaps the most important distinction between LEDs and OLEDs is the type of light they produce. LEDs are direct point sources that offer tight and focused beam control. OLEDs, in contrast, are a thin, planar, diffuse, and glare-free source, and are well suited for ambient lighting or backlighting applications such as signage.
One factor that affects industry adoption of any light source is its performance and, more specifically, its efficacy, or how many lumens are output for every watt a source consumes. As of the U.S. Department of Energy’s (DOE) October 2016 OLED Stakeholder Meeting Report, the efficacy of OLED panels ranged from 40 to 50 lumens per watt (lm/W), compared to the measured 98 lm/W of commercial LED luminaires in product testing for the DOE’s now-defunct LED Lighting Facts database. Today, OLED panels can output 85 lm/W.
With these technical advancements come an unprecedented opportunity to challenge conventional luminaire form factors. Still, the lighting industry’s mindset remains a lingering challenge. Because the performance of first- and second-generation OLED panels could not compete with that of LEDs, designers considered OLEDs more suited for specialty installations and one-off decorative designs. One of the first OLED-only light fixtures was Ingo Maurer’s Early Future task lamp, which featured 10 5.2-inch by 1.3-inch OLED panels on a glass substrate.
Designed in 2008 and manufactured by Osram Opto Semiconductors, the Early Future task lamp was mostly an experimental exercise, as the cost of OLED panels at the time were prohibitively expensive. “The design community has a preconceived idea of what OLED is about and what it can do,” says Jeannine Wang, the San Francisco–based director of design partnership for Acuity Brands Lighting’s Custom Architectural Lighting Solutions (CALS) group, which is tasked with developing OLED luminaires for the commercial marketplace.
Advancing OLEDs
OLED panel manufacturers are not alone in driving the technology’s adoption. Luminaire manufacturers have a vested interest, motivated by the source’s quality of light and potential for new form factors and applications. OLEDWorks is another company, along with Acuity, that is seeking to advance the technology and educate lighting professionals about OLEDs.
Headquartered in Rochester, N.Y., OLEDWorks is the only OLED panel manufacturer based in the United States. The company acquired Philips’ Lumiblade OLED technology platform and business unit in 2015 and maintains offices in Aachen, Germany, where the Lumiblade technology originated. OLEDWorks has developed three generations of OLED panels, all with increasingly greater efficacies and life spans, which in turn have helped to reduce OLEDs’ overall cost.
The latest generation, Brite 3, released earlier this year, introduces a round shape to the existing square and rectangular OLED panels, in direct response to specifiers’ request. The round OLED can deliver up to 200 lumens and 75 lm/W, acceptable for functional lighting applications, while the square and rectangular panels can deliver up to 300 lumens and 85 lm/W. All panel shapes offer two color temperatures—3000K (warm-white) and 4000K (neutral-white)—and a color rendering index of 90-plus.
OLEDWorks’ customers “love the light quality” of its latest OLED family, says Gina Phelan, the company’s director of business development. Coupled with the higher efficacy and life span approaching 100,000 hours, it makes OLEDs an enticing option for the illumination of architectural spaces, despite their still-higher cost over LEDs.
Also included in the company’s Brite 3 family is Curve, one of the first bendable OLED panels to hit the commercial market. (LG Display also makes a bendable OLED panel.) Produced on 0.1-millimeter-thick Corning Willow glass, Curve’s thickness totals approximately 0.5 millimeter, making it among the thinnest products available to date.
Acuity has also prototyped several OLED luminaires and hybrid OLED–LED luminaires that have now entered the company’s brand portfolios. With products that include the ceiling-mounted Revel and Trilia fixtures, the Nomi wall sconce, and the Canvis pendant, Acuity hopes that specifiers will recognize OLED luminaires as market-ready lighting solutions.
OLEDs at Work
Though the latest technical specs are promising in themselves, few things are more convincing to designers than real-world installations. Though some office spaces currently use OLED luminaires, it wasn’t until the DOE’s 2016–2017 Gateway program installation at the offices of DeJoy, Knauf & Blood (DKB), an accounting firm in Rochester, N.Y., co-founded by OLEDWorks chairman and co-founder David DeJoy, did the lighting industry have an installation with measured performance data and user feedback that could serve as a reference for evaluation.
The overall project is notable for a few reasons. First, it incorporates several OLED fixture types—tasklighting and decorative accents—throughout the office, including several from Acuity Brands, to complement the workplace’s primary fixtures (LEDs) and natural light. Second, the OLED luminaires were installed at “visually prominent” locations, including conference rooms and breakrooms so that employees could experience and perform activities under OLED lighting conditions.
The study included fixtures with OLEDWorks’ Brite 2 panels and dedicated OLED drivers (both integral and remote) that were connected to zero-to-10V dimmers. According to the accompanying July 2017 Gateway report, none of the OLED panels or drivers failed during the nine-month test, nor did any of the panels exhibit flicker exceeding what’s allowable by IEEE (the Institute of Electrical and Electronics Engineers). The study also found that all of the OLED fixtures delivered between 21 lm/W and 58 lm/W, and that luminance levels (the amount of light provided) was measured as high as 9,318 candelas per square meter and as low as 3,000 candelas per square meter when employees dimmed the fixtures. Those readings are significant because they demonstrated that the OLED fixtures provided a sufficient and comfortable amount of light to perform work without any visual discomfort.
Overall, DKB employee feedback was positive with workers noting that the OLED fixtures provided a “soft, minimal shadow lighting” that made facial expressions easy to see and recognize. They also noted that the additional ambient OLED light helped to increase the overall room brightness and was particularly good for delivering light to vertical surfaces without glare. And, finally, participants lauded the ability and ease by which they could dim the panels.
To ensure that the ongoing study remains up to date, some of the hybrid LED/OLED fixtures first installed were replaced with newer OLED products introduced in 2017. With such positive performance data from the second generation of panels, the numbers only stand to improve with the third generation as well as future generations.
Expanding OLEDs’ Design Potential
This past spring, Brooklyn, N.Y.–based studio Rich Brilliant Willing (RBW) used OLEDWorks’ panels for its “Light Inflection” installation at the company’s SoHo showroom. As the first foray into OLEDs for the design studio, which had until that time focused on LED fixtures, the project explored the technology’s sculptural and functional potential, including five different lighting concepts and oversized sconces and pendants in S-curves and arcs of up to 12 feet long.
Because RBW wanted to emphasize “the extreme flexibility and the evenness” of OLED light, says founding partner and director of development Theo Richardson, the designers used “similarly slim, flexible components: long swaths of 1/8-inch-thick aluminum and 3D knit fabrics” in the design of the OLED luminaires. This allowed RBW to “explore simple gestures: light and shadow, flexibility, the bending of material under its own weight, and the irregularity of fabric stretched across a surface.”
As a result, the work offers a design perspective that blends experimentalism with pragmatism and is not limited by the traditional processes of luminaire design. “The success of our design practice stems from embracing and adopting technological advancements, pushing the boundaries of our services and product offering,” Richardson concludes.
The Outlook of OLEDs
At press time, the 20th annual OLEDs World Summit was underway in San Francisco. The greatest challenge for the OLED community will be how it charts the technology’s course for growth and development beyond the automotive and display-screen markets.
To that end, OLED panel manufacturers are aware of the growing interest in architectural lighting applications. The OLED Coalition, an industry-based organization, was formed in 2013 to provide a forum for sharing technical information and market data. Members include large- and small-scale companies involved in different types of OLED panel production.
In 2009, Barry Young, now the Austin, Texas–based CEO of the OLED Association, predicted at the OLEDs World Summit that the OLED industry might be as large as $900 million by 2015. According to the OLED Association website, “In 2016, OLED displays dominated the high-end of the smartphone market and in total shipped over $15 billion U.S.” What percentage of that OLED panel market is dedicated to lighting applications is unclear.
OLEDs hold great potential in architectural lighting applications and luminaire design. But if the design community is to acknowledge OLED as a viable, market-ready light-source option, it will require more lighting manufacturers to get on board. “We need all manufacturers to embrace this [technology] and get behind it so it gives confidence to the specifications market,” says Ron Schimmelpfenning, vice president of Acuity’s CALS group. “Designers need to see that this is real and that there are options.”
So long as OLED panel development continues to yield increasing efficacies and, as a result, more accessible price points, then OLED lighting solutions stand a chance to compete with LEDs for certain applications. Most importantly, the lighting community needs to remember that OLEDs are a complementary technology and market to LEDs with an extraordinary ability to redefine lighting quality, form factors, and ultimately how light is integrated into architecture.
