Mapping Temperature in OLED Displays Using CCD Thermoreflectance

Effective thermal management is essential to engineering organic devices, since heating accelerates their degradation. However, as pixels in organic light-emitting diode (OLED) displays continue to shrink, an important tool for thermal management, infrared thermography, approaches the limits of its spatial resolution. To address this problem, we adapt high-resolution thermoreflectance imaging, which measures minute changes in reflectivity of visible light, to map temperature in a commercial OLED display. We identify a slowly varying thermal signal and find strong evidence of thermal crosstalk, in which a biased pixel heats up its nearest neighbors, even when the neighbors are unbiased. Such crosstalk is indicative of insufficient heat dissipation, which can lead to reduced display lifetime.