Organic light-emitting diodes, OLEDs for short, feature a light, thin structure, high efficiency and homogeneous luminance density. They do not have any preferred direction of radiation but emit their light in all spatial directions. For this reason, their application in contexts requiring the illumination of a defined area, such as in quality assessment or in the automobile sector, has been limited so far.
OLEDs are structured in layers. The electrically active areas rest on the carrier substrate, which usually consists of glass or plastic. The electrons of the cathode layer go through the intermediate organic layer and on to the anode layer, creating light energy that radiates through the transparent substrate. Generally, secondary optics is an option to influence light. However, owing to the broad spread of radiation coming from the OLEDs, it cannot transform the light without losses.
At the Light Technology Institute at KIT, scientists have now developed a manufacturing process with which optoelectronic components such as OLEDs and photo diodes with improved light properties can be produced. This enables the production of OLEDs whose light radiates in a desired direction.
In the new process, gridded surfaces of micro-lenses are made first. Then the beam-steering OLEDS are produced, with an insulating layer of photoresist being applied between the anode and the organic layer that is illuminated by the micro-lenses during production. The lenses focus the light, so that the photoresist responds at the focus. Light energy is only generated at these non-insulated points when the OLEDs are operating. The resulting illuminated dots automatically lie in the focal area of the micro-lenses. In this manner, the light is radiated precisely in the direction from which it was illuminated during manufacture. At the same time, inner reflection is avoided, so that light yield increases by 30 per cent.
The KIT researchers have already produced and tested OLEDs. KIT is seeking partners for research and for the industrial application of the manufacturing process.
Your contact person for this offer
Dr. Aude Pélisson-Schecker,
Karlsruhe Institute of Technology (KIT)
Innovation Manager Energy, Innovation and Relations Management (IRM)
Phone: +49 721 608-25335