light+building 2018

••• 7 ••• Innovationen mbn 158/5 New creative options for lighting designers OLED emission systems feature an adjustable colour range integrated on exible substrates W ith their unique character- istics like bendabilty, seg- mentation, transparency, and their nearly unlimited range of shapes, organic light-emitting di- odes (OLEDs) facilitate diverse new design opportunities by vir- tue of their being efficient areal lighting sources fabricated on flexible substrates. Fraunhofer FEP specializes in the development and fabrication of OLED modules with unconven- tional properties for specific cli- ent designs. The researchers offer OLED emission systems fea- turing an adjustable colour range integrated on flexible substrates. These types of OLED modules are able to switch the emitted colour between two different colour temperatures. In this way, a yellow-blue bi-colour emission system can not only be switched between the pure emission colours of yellow and blue, but white light can also be generated through simultaneous activation of both colours. The integration of adjustable-colour OLEDs on flexible substrates brings their employment on curved surfac- es in vehicle interiors such as roofs and curved fixtures into the realm of the tangible. In the meanwhile, the range of choice for substrates has also been broadened. Flexible OLEDs can be fabricated on metal and plas- tic films just as they can be on ultra-thin glass. Background In 2015, scientists of the Fraun- hofer FEP were successful for the first time in processing adjustable- colour OLEDs on rigid substrates. This facilitated the extension of the application spectrum of OLEDs, such as for integration into vehicle interiors where the light- ing levels should be controllable as a function of the time of day. Imag- ine employment as ambient or ac- cent illumination, such as for light- ing in museums and exhibitions, where the adjustability of colour from just a single lighting compo- nent can present the works exhib- ited in different colours of light. Adjustable-colour OLED on flexible substrates Photo: Fraunhofer FEP