AU Optronics developed new round AMOLED displays, which they call True-Circle displays, which have slimmer salient corners compared to AUO's current round OLED displays. This enables watch designers more flexibility with their designs.
AUO is demonstrating two such displays, with a diameter of 1.2-inch and 1.4-inch. AUO aims to start mass producing these new displays in the second half of 2017. You can see how these displays look compared to AUO's current "Full Circle" displays.