OLEDs – organic light-emitting diodes - are relatives of LEDs but are organic, meaning their major building blocks are organic (carbon-based) materials which emit light across their surface, instead of producing a single point source of light as the LED does. The current metrics of OLEDs are not quite equal to present LED technology but the field is advancing at a fast pace and OLED technology will soon be another artificial lighting advancement that will improve more lighting applications and develop other ideas that will potentially advance and change many different things in our lives. Currently, there are a small amount of OLED products produced which have a number of comparable LED metrics but the overall quality and cost verses LEDs is not yet generally comparable and OLEDs are still years away from being useable as general sources of illumination.
The US Department of Energy (DOE), in 2016, published the Solid State Lighting (SSL) R&D Plan which lays the path for future improvements in both the LED and OLED fields. In the OLED arena, the areas of materials and light extraction are of the highest priorities in R&D. Work in these areas will assist in advancing the efficiency gap between LEDs and OLEDs. The control of beam patterns in the extraction of the surface emitted light has been a greater challenge than it was with the point source light associated with the LED technology. The cost issue is also a gap that needs to be closed, and improving manufacturing techniques and materials are a point of concentration that will, eventually, help lead to future OLED applications which will equal, accentuate and, in some cases, replace current LED applications.
Flat glass substrates are currently the mode for developing panels of OLEDs. The arrays are made up of smaller panels which are about 100 millimeters square. The size range and aspect ratios are advancing and will certainly help in the successful commercial development. The promise of producing panels created of thin flexible materials which can be bent, rolled, folded or shaped as desired is quite real. These potential properties offer many advantages over other lighting technologies, including LED.
One of the issues with OLEDs is, as the panels age, the voltage across the panel will rise and the driver must be able to adapt and adjust so the light output does not diminish due inability to maintain the correct drive current. At this point in time, most OLED lights utilize more readily available LED drivers instead of dedicated OLED drivers and that in turn may result in efficiency losses due to the fact that LED drivers are not optimized for OLED application. Other issues involved in using LED drivers include dimming characteristics which may introduce flicker. In the case of OLEDs, it is quite important that the driver be able to provide the correct amount of power throughout the lifetime of the OLED. This aspect of the development is currently being strongly worked on and documented so the improvements and results of improvements can be applied to the OLED technology throughout the industry.
The color metrics of OLED lights – color rendering index (CRI), and others - are not quite up to the standards of current LEDs but future developments will certainly change that. Currently, what is available is generally 2700-300K, however some manufacturers offer 3500 and 4000K but at the loss of efficacy.
Just as with the early development of LED lighting, which dealt with issues such as bad color, short life, low output, driver failure, fast light decay, flicker, bad connectors, no standards, and more, the OLED field is struggling through a similar number of challenges. The advantage that OLED developers have is that they have been able to watch what the LED technology has done in working through similar problems. The OLED systems are not yet capable of matching the cost, color quality, energy standards, dimming capabilities, and other qualities which would make them comparable, competitive, and even complimentary to current LED luminaries. However, the day will arrive when all that will happen. Eventually the OLED technology will create lighting which will be very adaptable to odd shapes and applications which no current lighting technology can currently match.
As always, if you need help with your LED lighting projects, please feel free to call Polar Ray at 303-494-5773 to speak with a lighting consultant. Thank you for perusing the Polar Ray website.