Fast electro-thermal simulation of large area OLEDs in natural convection environment

Abstract

Organic LEDs can be used not only in displays but also in intelligent light sources. Unlike inorganic LEDs, OLEDs do not function as point-like but as surface light sources since manufacturing of large area light sources is more feasible with OLED technologies. Despite their lower luminous efficacy this makes OLEDs still an attractive option especially in high end indoor applications, The major issue in such applications is the homegenity of the luminance of the large OLED panels. In natural convection environment the temperature difference in the same device can reach 20–30°C which can result in up to 30–40% difference in current density and thus in the luminance. CFD simulation is the obvious way to handle this problem but integration of a CFD solver in an OLED simulator may be difficult and the solution times are high. This paper presents the application of three natural convection models for vertical plates in an electro-thermal field solver based OLED simulator as thermal boundary condition. Simulation results of a free-standing 50∗50 mm2 active surface OLED, surrounded by still air, are compared with measurement results.