AES Semigas


16 July 2021

Micro-LED display development unhindered by COVID-19

The importance of displays has become more significant during the COVID-19 pandemic, as the need to have a display for remote communication has increased. An emerging display type is the micro-LED display, which has the potential to become the next-generation mainstream due to its ability to be fabricated in array sizes ranging from from tiny to huge. The challenges and opportunities of this are discussed in IDTechEx’s report ‘Micro-LED Displays 2021-2031: Technology, Commercialization, Opportunity, Market and Players’.

COVID-19 has not stopped the development of micro-LED displays. With the Consumer Electronics Show (CES) and Display Week, as well as a number of events being put online, it can be seen that the progress and new launches of micro-LED display prototypes and products are not greatly affected, says IDTechEx.
The increasing activity of display suppliers can be seen from the cumulative investment and increasing number of patent filings, as well as the prototypes/products introduced by micro-LED vendors, such as AUO, PlayNitride, RiTdisplay, Samsung, LG, Sony, TCL, Tianma, Konka, Glo, Plessey, JBD, X-Display, VueReal, CSOT, Sharp, Kyocera etc.

However, prototypes for proving the readiness of technology through lab/fab-scale production are very different from mass-manufactured commercial products. The latter require zero defects for consumer products. Although the science has been proved, there are further engineering and manufacturing issues.

For example, conventional LEDs can reach external quantum efficiencies (EQEs) of ~70%, while micro-LEDs of less than 10┬Ám may struggle to reach 20%. Red LEDs are especially challenging due to their low EQEs and brittle features. Tiny micro-LEDs have a large surface area, which may lead to more defects during the fabrication process. Therefore, solving engineering/manufacturing challenges is important, including die size miniaturization while maintaining high efficiency, chip design, and chip manufacturing technique improvement. Other issues include mass-transfer yield and accuracy, defect repair, testing, uniformity, light management, color conversion, etc.

To fabricate a micro-LED display, many technologies and processes are involved, such as epitaxy, photolithography, chip fabrication, substrate removal, inspection, mass transfer, bonding and interconnection, testing, repair, backplane and drive IC, etc. After years of development, some technology difficulties have been solved, while new challenges sit in front of us, says IDTechEx. For example, several years ago most effort was concentrated on die miniaturization, chip design, and mass transfer, etc. Recently, more players have realized that it is key to have a complete understanding of all the processes. Therefore, more people are putting increasing emphasis on technologies such as inspection, repair, driving, image improvement, light management, and high-volume production equipment.

Another interesting phenomenon is the increasing number of partnerships, mergers, acquisitions, joint ventures, and further investment. This aligns with the display cycle trend. There was hype in the micro-LED display one or two years ago, but now major players are gradually establishing their roadmaps. Mini-LED displays and large signage & TVs are introduced by many vendors, and in the meantime players are still working on micro-LED displays. Compared with previous years, consolidation is becoming more evident.

Following on from the LCD industry, China has likewise invested greatly in micro-LED displays. Before 2019, BOE was not active in the micro-LED display arena. However, after 2019, BOE jumped to be the top company in terms of the number of patents filed. Sizeable investment also indicates huge interest. Although there are quite a few start-ups in Europe and America, it seems that East Asia will dominate micro-LED display development, reckons the report.

Tags: microLED