Light extraction analysis of organic light emitting diodes fabricated on high refractive index glass scattering layer

摘要

Optical analysis was performed for Organic Light Emitting Diodes(OLEDs) formed on a high refractive index glass(high-n-glass) scattering layer. Angular dependency of luminance for OLEDs fabricated on high-n-glass substrate with a hemisphere high-n-glass lens has a good agreement with the emitting directivity calculated by an interference simulation. Applying this emitting directivity, ray trace simulation was performed for OLEDs on various types of substrates and hemisphere lenses. The calculated out-coupled light flux has a good agreement with the measured values. From the experimental and simulation results, it can be concluded that out-coupling efficiency is 1.7 times compared to the reference, and about 55% of lights out of the OLED device can be extracted to the air by the high-n-glass scattering layer. In this case, the probability of light out-coupling as a function of emitting angle starts at 66% at 0°, and still remains more than 30% up to 70° from the normal direction.