In April 2019 Reuters reported that Japan Display (JDI) signed a deal with Apple to supply it with AMOLED displays for its smartwatches, and today JDI's new CEO Minoru Kikuoka said that the company recently started producing OLED displays - likely indeed this is low volume production for Apple's wearables.
Apple's Watch Series 5 (its latest generation) features a 324x394 1000-nits always-on LTPO AMOLED display (368x448 on the 44m model). Apple is currently buying these OLED displays exclusively from LGD.
In August 2017, Japan Display announced a last-resort strategic focus on OLED displays as the Japanese display maker failed to shift to OLED displays in time, and since then the company struggled to secure the funds needed for mass OLED production. Only a few days ago its largest potential investor (the Harvest Group) decided to cancel their planned investment.
Kukuoka updates that its unnamed US-based customer (which is likely to be Apple) is likely to increase its participation in the "bailout" to $200 million, the JDI hopes to close a 50 billion Yen ($467 million) round by the end of October.
This bailout may save JDI in the short term - but it won't be enough to initiate real OLED mass production, and JDI confirms this. The company does not have any immediate plans to start its own OLED smartphone panel production and discussions on this will only begin after the bailout is finalized.