Back in May 2014, Apple acquired LuxVue Technology, a private company that develops micro-LED based displays. Very little was known about this company and its technology, but since then interest in micro-LED displays is obviously higher.
Candice Brown-Elliott, the creator of the Pentile Matrix technology (and the CEO of Nuovoyance), says that micro-LED has the potential to be truly disruptive. While it's still in an early stage, and using it to create large display is very challenging, a micro-LED display is attractive as it may be more efficient than an OLED display (as LEDs are currently more efficient than OLEDs). Some speculate that Apple aims to use such displays in future Watch devices as making a smaller display is obviously easier at first.