A new draft has been published, stating that Apple is using a new supplier Taiwan SMT. See the brief text here.
It''s still unclear when we can anticipate the first OLED iPad, but recent estimates have ranged from 2023 to 2026. However, a new supply chain study today suggests that Apple is concerned that the type of OLED used in the Apple Watch and iPhone may not be comparable to the iPad.
It is concerned that iPhone-like OLED panels might show visible warping if used for displays larger than 10 inches tall.
iPhones use flexible polyimide film OLED
The first OLED screens were stiff ones, with a glass substrate. Today, most smartphones, including iPhones, use polyimide films in place of glass.
Polyimide''s film offers a number of advantages over glass, including reduced costs, improved production methods, and increased flexibility.
Although flexible OLED is helpful for curved screens and folding ones, it also makes possible the ultra-thin bezels seen on modern iPhones. The display extends beyond the visible area and curves back inside the casing, concealing the non-usable edge areas.
First OLED iPad expected to use hybrid screen
Flexible OLED screens have a drawback, but they aren''t comparable to larger displays. In particular, a portion of the manufacturing process may result in a tiny but noticeable amount of warping.
For this reason, The Elec claims that Apple is likely to use a hybrid form of OLED for iPads.
TheElec has learned that Apple will employ hybrid OLED panels in its first OLED iPad that it will launch a few years later.  Hybrid OLED panels refer to companies that use both rigid OLED panels and flexible OLED panel technologies 
However, a hybrid OLED panel combines a glass substrate like rigid OLED panels do, but also incorporates flexible OLED panels thin-film encapsulation. Apple isnt too keen on using flexible OLED panels __ which are mostly used in premium smartphones __ some parts of the screen may look crumpled.
The problems are likely to be caused by how flexible OLED panels are constructed. During their production, glass substrates. Polyimide varnishes in liquid form are deposited on the top of the substrate, and the glass is then removed through lasers. The remaining solidified polyimide is the plastic substrate. During the laser removable, some parts of the polyimide may be warped from the heat.
This warping is too small to be seen by the naked eye on small displays, like iPhones. However, it can be only visible on screens larger than 10 inches, making it less suitable for iPads.
Apple may be able to handle this problem, in which case it might be able to use traditional flexible polyimide screens, but right now, the message is that it will follow the same strategy.
Samsung and LG are planning a next-generation technology called Ultra-Thin Glass (UTG), which might be developed in time for the first OLED iPad. Currently, this is expected to be about a year away from commercial manufacturing.
Update: Apple said to be using new supplier
A Digitimes report also supports The Elec''s previous one, claiming that Apple will utilize a new supplier for the manufacturing, Taiwan Surface Mounting Technology (Taiwan SMT), alongside Samsung and LG.
Here are a few pictures of what we expect of OLED iPads.