HP Labs Technical Reports

High Luminance from Thin Film Electroluminescence Devices

Mueller-Mach, Regina; Mueller, Gerd O.; Alinsog, Elmer; Helbing, Rene

HPL-96-104

Keyword(s): electroluminescence thin film devices, high brightness

Abstract: Thin Film ElectroLuminescence (TFEL) can be used for many applications besides displays. Most of them demand high brightness/radiance. Coping with the problem of thermal dissipation by reducing the duty cycle the radiance limit is set by efficiency and its decrease by dopant saturation. No other mechanism could be identified except for ZnS:Mn, which shows nonlinear cross-relaxation between closely spaced excited dopants. Values of 50 mWcm^-2 (40,000 cdm^-2) for face emitters and 1 Wcm^-2 (1,000,000 cdm^-2) for edge emitters appear to be the practical limits, without the reasons clearly identified.

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