Editorials

OLEDs Need Much Improvement

By Lightimes Editor, Scott McMahan

The U.S. Department of Energy (DOE) released the CALiPER Report 24, which discusses the performance and accelerated lifetime testing of OLED luminaires. The report is the first CALiPER report that discusses the independent procurement and evaluation OLED luminaires.

As expected, OLED luminaires have a long way to go before they catch up with the performance, efficacies, and lifetimes of current LED luminaires. The report notes that currently there is not an accepted standard specifically for accelerated life testing of OLED luminaires. A new standard would have to reveal all potential failure methods in OLEDS, which so far are partially unknown. However, the DOE was able to conclude that OLED lifetimes and efficiencies are far below that of conventional LEDs currently on the market.

PNNL laboratories conducted most of the testing and RTI performed the stress testing.

Among the OLED luminaires tested, the overall efficacy was found to be considerably lower than contemporary LED luminaires. The efficacy ranged from as low as 23 lumens per watt (LPW) up to 45 LPW. According to data from the OLED panel manufacturers, the LPW ranged between 42 and 55. The CALiPER testing found that much of this efficacy reduction is due to very inefficient driver and transformer selections and combinations.

The report pointed out that the wider availability of dedicated OLED drivers should improve OLED light efficacies in the near future.

The drivers for all four CALiPER OLED luminaire types were different. Some OLED luminaires used a single driver and others used a combination of electronic components for voltage transformation, conversion from AC to DC, and voltage/current control.

The testing found that the OLED luminaires performed very closely to the manufacturers’ published technical data, where available. Also, all of the tested products provided a soft, diffuse light with a roughly Lambertian emission.

Unlike LED lighting technology which is now in a mature stage of development, the DOE report says that OLED panels, drivers, and transformers are still in a steep curve of development. Much improvement is required before the technology can reach a mature stage.

The goals of OLED developers include improving lifetimes, efficacy, lumen maintenance, and color quality. Other technological goals include developing a broader range of color temperature options for OLEDs and producing higher efficiency drivers. Along with the improvements in lifetime, developers are working on enhancing OLED robustness and resistance to high temperatures, high humidity, and rough handling.

OLED lighting is really in its infancy in terms of its development and adoption. Improvements in its performance and longevity are only part what will make it into a mature technology. The greater involvement of industry and academia in the development effort would be needed to make OLEDs an economically sensible choice. I don’t see that happening anytime soon.

Additionally, the industry has to get together to create standards for accelerated longevity testing. While the testing standard that the study used, LM-79 08, was developed for LEDs, it would have to be modified for OLEDs, and not all of the potential long-term failure modes are even known.

While the DOE says that such improvements could make OLEDs a trusted solution for architectural lighting, a considerable amount of development work and performance improvements are needed before OLEDs can mature as a technology.

More Recent Commentaries and Editorials

Not All Blue Light the Same

Guest Editorial

By John Bachner Executive Director of the National Lighting Bureau AMA LIGHTING RECOMMENDATIONS BASED ON WRONG METRIC, SAY…
Read More
EnOcean Alliance Contributions to Lighting and IoT
A consortium of companies known as the EnOcean Alliance works together to develop and promote self-powered wireless monitoring and control solutions for sustainable buildings. To Date, the alliance…
Read More
The LED Lighting Industry of Last Year; And Predictions for Next Year
During 2016, the LED lighting industry witnessed the expanded adoption of LED lighting across all segments. More and more companies began manufacturing LED lamps and luminaires. This increased…
Read More
Election Results in Expected Cannabis Boom; Grow Light Makers to Benefit
While much of the media and the world was surprised with the results of the U.S. election, one part of the LED lighting industry that is sure to get a boost are the companies that make LED grow…
Read More
OLEDs Need Much Improvement
By Lightimes Editor, Scott McMahan The U.S. Department of Energy (DOE) released the CALiPER Report 24, which discusses the performance and accelerated lifetime testing of OLED…
Read More