High‐Resolution 960 × 540 and 1920 × 1080 UV Micro Light‐Emitting Diode Displays with the Application of Maskless Photolithography
Meng‐Chyi Wu, I‐Ting Chen
Abstract
Herein, active matrix 370 nm ultraviolet (UV) micro light‐emitting diode (micro‐LED) displays with full high‐definition resolution of 960 × 540 and 1920 × 1080 and high pixel densities of almost 2000 and 3200 pixels per inch (PPI), respectively, are reported. A novel self‐aligned process is used to fabricate the 1920 × 1080 micro‐LED array with the inverted trapezoidal‐shape mesa, which is different from the conventional vertical mesa for the 960 × 540 micro‐LED array. In addition, the single pixels with the diameters of 8 and 5 μm on the 960 × 540 and 1920 × 1080 microarrays exhibit excellent characteristics, including the low forward voltages of 3.35 and 3.29 V at the currents of 17.4 and 4.4 μA, extremely low leakage currents of 19.5 and 9.4 pA at −10 V, and high light output powers of 150 and 71 μW at 1 mA, respectively. Through flip‐chip bonding technology, the 1920 × 1080 micro‐LED display has a higher light output power of 2.6 mW than the 960 × 540 micro‐LED display of 1.8 mW at the same driving current of 100 mA and voltage of 5 V. Both the UV micro‐LED displays demonstrate the delivery of graphic images and simple pattern‐programmable maskless photolithography on resist‐coated wafers.