Formable Luminescent Films Can Be Backmolded

Polycarbonate electroluminescent films can provide light in homes, cars, cellphones, and even inside ladies’ handbags. While it has been possible to make flat light-emitting films, they now can be formed into 3D shapes with tight radii, thanks to technology developed by Lyttron Technology GmbH, a new start-up subsidiary of Bayer MaterialScience AG in Cologne, Germany. Lyttron uses screen printing to deposit the electroluminescent structure—essentially a parallel-plate capacitor comprising up to 20 layers—on Bayer’s Makrolon PC film. Lyttron uses back-side printing to protect the special layers from damage. When connected to a source of electric power—mere millivolts—the structure emits light without heat. The entire surface of the film emits light uniformly. No diffuser sheet is needed. The coatings can emit light in blue, green, orange, or white, and can be printed on matte or glossy surfaces. Lyttron developed a high-pressure forming method for 3D lighting shapes. The formed film can be used as an in-mold decorating insert and backmolded by injection molding. Lyttron’s first application was a strip for illuminating the inside of women’s handbags. Also commercial is a self-lighted car license plate.