Showa Denko K.K. (SDK) recently announced that it had developed a new structure for its organic electroluminescent (organic EL) devices achieving approximately 40% in light output, which represents the highest level in the world.
A new model of lighting, using SDK's coated phosphorescent-polymer-based organic EL devices with the new structure.
SDK has achieved a 30 lm/W emissive efficiency for its coated phosphorescent-polymer-based organic EL devices, representing the highest level among coated-type organic EL devices that have been announced in the world, the company claims.
The coated type production process of organic EL devices, compared with the deposition type, is attracting keen attention because it consists of a few layers formed by coating polymer without the use of vacuum, providing the opportunity for substantial cost reductions and for the production of large area-emission panels in the future.
The new structure has introduced a layer of dielectric/heat conductor that adjusts reflection of light. The new layer helps reduce the percentage of light trapped in the device, improving the light output. The dielectric/heat conductor layer, having high heat dissipation efficiency, prevents heat deterioration of the emitter, prolonging the device life.
New structure Conventional structure
SDK has already achieved a luminance half life of approximately 10,000 hours for white lighting through improvements in the phosphorescent-polymer materials. The company will continue working with SRI International, a non-profit research organization based in California, U.S.A., and Itochu Plastics Inc. (CIPS), to improve the design of device structure and start selling samples on a full scale in 2010 for use in the general lighting market. The three parties will also work to improve coating property of the phosphorescent polymer and prolong the device life, aiming to achieve a 150 lm/W emissive efficiency and a luminance half life of approximately 50,000 hours for white lighting by 2015.