Determining 2-D Optical Characteristics- Dependent Surface Temperature of Organic Light-Emitting Diode

This article proposes a method for determining the 2-D photon counts distribution of organic light-emitting diode (OLED) devices. Photon counts distribution is proved to be an effective method of distinguishing the performance of current spreading. Because of the close relationship among temperature, photon counts distribution, and current density, a quantitative predicted method of 2-D photon counts for OLED devices is proposed. The photon counts distribution has a minimum value due to the range of the physical parameters in the proposed model based on the practical properties of OLED device. For a given current, the location of minimum photon counts can be determined. The proposed model provides a new multiphysical model, including photon counts distribution and photon counts nonuniformity of OLED device with electrical–thermal–optical properties. With different injection current and ambient temperature, the nonuniformity of OLED’s photon counts distribution is analyzed using a high-speed camera with noncontact and high resolution. The experimental comparison shows that the maximum error of photon counts distribution of OLED device with different current and ambient temperature is less than 6%, proving this method’s accuracy. The 2-D photon counts distribution of OLED device can be temperature or current density crowding resulting in heat accumulation and the restriction of the emitting photons; hence, thermal flux is an essential factor influencing the photon counts distribution. It is useful for the designer to control the parameters of OLED device and driver to meet the requirement set in the optical standard.