From the beginning of the first commercially successful electrically powered artificial lighting, which was the Edison incandescent bulb, to the current LED technology, all the different electrical lighting technology that has occurred between the commercialization of the two is on the list of artificial lighting that will soon be outdated by one form of lighting technology, that being, LED. However, man being man, the latest and greatest will someday be eclipsed by some other development(s). One of the current potential competitors is the OLED. OLEDs are organic LEDs and their main building blocks are materials which are organic, being carbon based. On the other hand, standard LEDs are silicon based but both are still considered as solid state electronics.
OLED technology has been around since 1960 but it has not been developed to the level that LEDs have accomplished. The first OLED that proved to be practical was developed in 1987 by a pair of chemists at Eastman Kodak. The device was a novel structure which resulted in a reduction in operating voltage and advances in efficiency. Currently, the technology is in a rapid state of development and there are a very small number of available OLED products which have metrics that compare to LED area lighting. However, the cost is quite high and, currently, that is one of the largest reasons that their widespread use for general illumination is still many years in the future. Unlike the LEDs, which produce a point source form of lighting, OLEDs are constructed in sheets which emit light in a diffuse pattern. The sheets can be made flexible which has put them to use in such places as automobile dash lighting and displays of all sorts. At this point in time their most prevalent use is in television screens. These televisions display incredibly lifelike imagery, so incredible that even some in the industry have insinuated that there is not a lot of room for improvement.
The cost is the first factor that developers are working on improving and the fact that OLEDs can be printed onto any suitable substrate by an inkjet printer or by technology as old as screen printing is a potential boon to cost saving production. This would potentially make them less expensive to produce than the liquid crystal display (LCD) technology that OLED technology could replace, and be more efficient, not only in energy consumption but in producing display images. The printing method could, theoretically, produce thousands of OLED devices per minute. However, one of the challenges of the operation is the degree of accuracy necessary for the registration of multiple layer devices so that they are correctly aligned – so they operate properly.
The fabrication of OLEDs on flexible substrates presents possibilities for many new applications. Some of the ideas that have developed from the technology are roll-up displays imbedded in fabrics, even clothing. The fact that plastics can be used as a substrate greatly broadens the field of applications as well. The plastic substrates used would not shatter as glass would in comparable LCD displays. One of the most recently announced advances is the development of flexible smart phone screens which will likely be put into production in the near future. That phone body will, in all likelihood be somewhat flexible itself. To that, I say, woohoo!; as a guy, I have gone from carrying a small phone in a front pocket to having to now put the larger variety in my back pocket, and sitting is a pain in the butt. Anyway, these incredible developments are just the tip of the iceberg in what might be possible with the further development of OLED technology.
Since the illumination from OLEDs is a diffuse form of light, it offers many aspects which no other light before it has afforded. The soft light produced could be more practical for large area lighting and is so soft that it can be viewed directly without the need for additional diffusers, shades, lenses, louvers and other technology which might be used to relax the glaring intensity of other lighting technologies. This diffuse light produced by OLEDs allows for their use in very close proximity to the work surface without the user experiencing glare, allowing for less light needed to properly achieve the task the light was meant to augment. Light fixtures themselves could be made entirely from substrates that could be as simple a flat light screen to lighting made into any imaginable shape. The future of OLED devices is very promising and the broad range of potential applications is incredible.
It is difficult to determine where artificial lighting will go in the future but one thing is for sure, development will never stop and improvements will undoubtedly continue.
This blog is the last part a multi-part writing which has briefly touched on the evolution of artificial lighting. 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.