During an OLED display Seminar in Korea, UniJet's CEO Kim Seok-Soon said that new advances in Ink-Jet printing technologies could enable displays that are over 500 PPI - and so make printing a viable technology to produce small and medium-sized OLED panels.
Kim says that current ink-jet printing processes can reach to to 150 or 200 PPI, which is good enough for TV production (enough for a 8K 55" panel in fact) but not good enough for small sized displays. However current laser-droplet measurement processes could enable discharge control of less than 0.1 μm and a volume accuracy of less than 0.1% - enough to reach 550 PPI. Kim estimates that such technologies could be ready for mass production lines by 2020.
Ink-Jet printing is currently being tested for OLED TV and monitor production. Earlier this month JOLED actually started commercial low volume production of 21.6" 4K panels, and other companies including LGD and BOE are looking into ink-jet printing of large-area oLED TV panels.