Numerical characteristics of the intensity distribution for a white organic light-emitting diode

Abstract

A statistical distribution function capable of numerically characterizing the unique intensity distribution of a planar white organic light-emitting diodes (WOLED) was theoretically investigated by fitting our experimental data obtained by microscopic goniometer (MG) system associated with an energy analyzer to the normal distribution function with amplitude, average, and standard deviation as adjustable parameters. The WOLED is one of the upcoming lighting sources with planar device structure without additional optical components. The intensity characteristic of a lighting source is crucial for practical purpose. The procedure of an optical design usually requires proper numerical tools to satisfy specific application by adjusting parameters. Relatively uniform intensity distribution of a planar lighting source is needed for a specific lighting application such as back-lighting (BL) for liquid-crystal displays (LCD) in which Regular white LED's (WLED) and light-guide plate are assembled as a planar module. Our intensity measurement of a WOLED revealed a unique pattern in which the relative intensities near central area are higher than that near the edge of the emissive area. This unique intensity profile is similar to the feature of Gaussian distribution function. Our preliminary result of applying Gaussian distribution function to numerically characterize the intensity profile of a WOLED suggests that the unique intensity profile can be represented by single distribution function properly.