The IR‐drop in the full AMOLED display panel caused by the pixel current is simulated within the mainstream SPICE toolkit to evaluate the display uniformity. Each electrical part of the display panel is simplified and equalized to allow the SPICE doing the very large scale calculation. The implementation of the full panel simulation and the results give better understanding of AMOLED panel design.
With the increase of user demand, higher brightness become a trend for the information display products, which makes efficiency roll‐off issue even more concerning in organic light‐emitting diodes (OLED). Here, we fabricated a set of red phosphorescent OLED structure for investigating the origin of roll‐off. By replacing different kinds of red dopant materials (RD‐1 and RD‐2) and red host materials, we found the main reason affecting efficiency roll‐off is dopant materials in emitting layer. Three key factors, including triplet‐triplet annihilation (TTA), triplet‐polaron quenching (TPQ), as well as the width of recombination zone were investigated. Firstly, the transient photoluminescence (PL) and electroluminescence (EL) results illustrated a longer excited state lifetime for RD‐2. Consequently, we demonstrated a relatively serious TPQ phenomenon in the unipolar device with RD‐2, which revealed a higher interaction probability between photon‐induced exciton and polaron. Finally, the OLED with RD‐2 showed apparently higher SCLC (space charge limited current) hole mobility in the hole‐only device. According to the recombination zone profiles and capacitance results, we proposed that a higher hole‐type space charge concentration in the device based on RD‐2 contributed to a higher polaron and triplet concentration in EML. Combined with a longer exciton diffusion length, a higher rate of TPQ was induced and resulted in relatively serious roll‐off phenomenon.
Foldable AMOLED display would be one of the most popular display type in the future. However, there are still many challenges that we need to overcome. Dropping ball test is one of the key problems to be solved in foldable OLED display. In this paper, we designed a contrast experiment and found that the cushion materials had an important effect on the dropping ball. The dropping height can improve from 3cm to 15cm when the module is without foam. At the same time, the bending property of module will not be changed.
Two approaches of fabrication of a 1.2 inch round AMOLED panel were discussed in this paper, in which one is glass+thin film encapsulation(TFE) and the other is polyimide(PI)+TFE. The innovative glass+TFE approach has the distinctive feature of ultra‐thinness compared to traditional glass+glass panel structure, and reduces yield loss in the PI and laser lift off(LLO) process compared to PI+TFE panel. The flexible PI+TFE approach can realize the bending of bottom border. Thus it fulfills true circular requirements for wearable displays.
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