Pixelligent: Improved Light Extraction For OLED Displays

October 05, 2016 // By Gregory D. Cooper
The root cause of the light loss in the OLED device is the fact that the light is produced in a high index material and has to be transmitted to air with a low index (n0 = 1). When light travels from a material with a high refractive index (n) into a material with low refractive index, if the incident angle is larger than a critical angle, it experiences total internal reflection (TIR), which is the mechanism behind almost all light loss in the device. There are a number of approaches that can be used to improve light extraction, all of which involve some variation in redirecting high angle light so that it is not trapped by TIR.