OLEDs are similar to electroluminescent lighting, in which a sheet of material is excited so that it emits light. An OLED light source is a thin, flexible sheet of material consisting of three layers, a polymer or sublimed molecular film sandwiched between two layers of electrodes, one of them transparent. Current passes through the material until it emits light through its transparent layer.
According to Uniax Corporation, in laboratory conditions, low-voltage OLED light sources can reach efficacies of 3-4 LPW. Unfortunately, such efforts produce too much heat and reduce the life of the light source. Manufacturers including Uniax, Philips Electronics NV, Photonics Spectra, Seiko Epson, Hoechst Innovative Display Technologies Inc., DuPont and Intel are all currently working on developing commercial OLED products.
What’s interesting about this light source still in development is that it may challenge our very perception of lighting and architecture in the future. Lighting designers often try to integrate lighting hardware and architecture in a cohesive manner; with OLEDs, the architecture may be the lighting hardware. Sheets of material can be cut and placed like “lighting wallpaper” or integrated with building materials such as wood, glass and other materials, converting them into luminous surfaces.
The Next Step
There are … many lighting applications that require only a few lumens, or tens of thousands of lumens, for which LEDs are ideal. In the past, most of the talk about LEDs has focused on efficiency. Now that the efficiencies have exceeded other light sources, future work should focus on packaging LEDs into useful products.
by Eric Strandberg, The Lighting Design Lab
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