Yole's analysts note that microLED technology could match or exceed OLEDs for most key display attributes, but yield is still and issue die to the an inherently complex technology. Manufacturing a 4K resolution display implies assembling and connecting 25 million microLED chips the size of large bacteria without a single error, with placement accuracy of 1µm or less.
This challenge alone appears daunting, but many others were still seen as potential showstoppers as recently as early 2017. Eighteen months later, some assembly technologies are delivering close to 99.99% or 99.999% yields, and small die efficiency is approaching or exceeding that of OLEDs, observes Yole.
MOCVD reactor suppliers also have credible roadmaps to deliver tools with the capabilities and cost ownership that the industry needs. Color conversion and other aspects are also progressing.
From demos to consumer displays
Increasing numbers of companies are demonstrating prototypes. Most are microdisplays on CMOS backplanes but the number of “large” displays prototypes is increasing as well, whether they are using discrete microdrivers like X-Celeprint or thin-film transistor (TFT) backplanes like AUO and Playnitride.
Many are still focusing on realizing their first prototype, but the most advanced have realized that bringing up the technology from the level of functioning demo to consumer-grade products might require more effort than anticipated. Among others, driving microLEDs is more complex than OLEDs and using standard low temperature polysilicon (LTPS) or oxide TFT backplanes might not be as straightforward as expected.
Sony’s demonstration of a full HD 55” microLED TV at CES 2012, more than six years ago, was the first exposure for microLED displays and generated a lot of excitement. Since Apple acquired Luxvue in 2014, many leading companies such as Facebook, Google, Samsung, LG or Intel have entered the game via sizable internal developments, acquisitions, like those of mLED and eLux, or investments in startups such as glō or Aledia.