OLEDs haven’t been a topic in our weekly articles on LED lighting . OLED is a short term for organic lightemitting diodes, and it is basically a new form of diode containing – obviously- organic matters. This merely new form of LED has an entirely new range offeatures compared to regular LEDs, which are primarily used for illuminating purposes. OLEDs, on the other hand, are mostly used as displays at the moment,and its illuminating features are yet to be discovered and developed. Within the OLED the substances are all organic; it can be mono-layered ormulti-layered. Either or both anode and cathode need to be transparent.

OLED lights have a growing popularity in display solutions due to a large scale of advantages the devicehas. First of all it is very light weight, thin and transparent. OLEDs can be printed on a thin layer of film or even a sheet of paper, so its flexibility and small size is a determining advantage. Displays applying OLEDs are generally brighter compared to other display solutions, also colours are generally vivid and have a wide range of colours. This range also contains black, which makesit a perfect solution compared to other back-lit solutions, where fully black display was difficult or impossible to achieve. Besides the high brightness, OLED displays are more energy-efficient in general, and have a wider viewing angle compared to other display solutions.

Due to these advantages and other exclusive features, OLEDs are a more and more commonly used display LED lighting solutions, and their use in lighting is another future perspective researcher and manufacturers need to achieve. Probably the most exciting feature of OLEDs is that they are available with PMOLED – passive matrix addressing, and AMOLED- active matrix addressing schemes as well, the latter known commonly as atouch screen. With AMOLEDs, each pixel can be addressed individually, therefore can control software attached to the display.

While OLEDs have distinctive characteristics allowing whole new forms of applications, the technology itself is still new, and a large number of issues need to be solved before their wider application. One of these difficulties is the relatively short lifespan of the OLEDs. This is mainly due to the blue components within the application, which only have approximately eight hours of lifespan with regular use – which is much less than the lifespan of other displays currently available on the market. Blue components are also more powerful within the application, becausethe human eye finds it more difficult to detect it than other colours, which actually results in a very high power consumption of the gadget when white isdisplayed, and also gives a more artificial look of the displayed picture. Thisdifficulty was mainly solved by the optimization of the colours within a single pixel, this way the differences in lifespan were also balanced out. OLEDs are also very sensitive to water, so their insulation is a crucial matter, and often excludes outdoor applications.

OLEDs are not used for lighting purposes at the moment, as far as traditional forms of lighting goes, and due to many of the above mentioned disadvantages, it will not be used until further development happened in its technology. Also, at the moment the brilliance of these diodes are not high enough for this application. Attempts have been made to use it as a main source of light: the first one was by Osram in 2009 November, but the Orbeos light panel, besides the above mentioned problems, had the disadvantage of high price as well.

OLEDs may not be suitable for main source of lighting at the moment; it allows a new range of unconventional lighting solutions, hopefully to appear on the market within a few years. Novaled OLED panels are a good example for this – these panels are transparent layers applied on a window for instance, letting in sun light during the day as a regular window, but serving as a source of light during the night. This background light solution can be obtained other ways as well. Since OLEDs can be printed on any thin layer or sheet, they are an alternative solution for wallpapers as a background light. OLED wallpapers – which are the combinationof art and technology – are due to appear on the market in 2012.

These peculiar solutions of lighting are going to revolutionize our idea about home or commercial lighting, hopefully in the near future.