3400 PPI Active-Matrix Monolithic Blue and Green Micro-LED Display
Xiaoxiao Ji, Fei Wang, Haojie Zhou, Kefeng Wang, Luqiao Yin, Jianhua Zhang
Abstract
With rapid developments in display technology and high-speed communication, augmented reality (AR) and virtual reality (VR) are emerging as next-generation display platforms for human–machine interactions. Recently, many significant strides have been made for the micro-light-emitting diodes (Micro-LEDs) display. However, to satisfy the requirements of AR/VR application, the size and resolution density of display have become extremely important. In this article, a 0.39-in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1024\times768$ </tex-math></inline-formula> blue and green active-matrix Micro-LED display with 3400 PPI featuring a pixel size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5.5~\mu \text{m}$ </tex-math></inline-formula> and a pixel pitch of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$7.5~\mu \text{m}$ </tex-math></inline-formula> was designed and fabricated. The blue and green Micro-LED displays exhibit excellent electrical and optical characteristics, including the low forward voltage of 3.3 and 3.2 V, and the brightness reach <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$7.2\times105$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.7\times106$ </tex-math></inline-formula> cd/m2 (nits) at 1 mA, respectively. These microdisplays demonstrated 8-bit grayscale images and videos vividly through the control of PWM frame generated by the FPGA board. We expect that the presented method could pave the way toward high-performance Micro-LED displays for AR and smart glasses.