Evaluation of OLEDs for VLC

In recent years, we have seen an increased use of organic light emitting diodes (OLEDs) for illumination 11 in indoor environments due to the softer light compared with the conventional inorganic LEDs. In addition, OLEDs 12 have been reported in visible light communication (VLC) systems, specifically for applications with lower data rates 13 such as information boards, camera communications and positioning. However, OLEDs need extensive electrical 14 and optical characterization if they are going to be fully exploited in VLC. This paper investigates characteristics of 15 a range of flexible and rigid OLEDs and compares them with inorganic LEDs. We show that, OLEDs have highly 16 linear power-current characteristics, and compared with rigid OLEDs with beam patterns closely matching 17 Lambertian profile, the flexible OLED’s radiation pattern is wider than Lambertian. Based on the measured 18 experimental data, a new expression for the OLED’s beam pattern, which follows the 3-term Gaussian profile, is 19 proposed. Moreover, we show that using larger size OLED in VLC links offers improved bit error rate performance 20 over a wide tilting angle up to 80° and a transmission path length up to 60 cm. 21 22