The Advantage of Barrier Films in OLED Encapsulation
Published: October 17, 2011 Category:

What makes more sense for non-glass, R2R OLED encapsulation – barrier films that can be laminated to the finished OLED devices, or directly deposited conformal barrier films?

For several reasons, lamination of a suitable barrier film is, in NanoMarkets' opinion, ultimately a better bet than technologies that require vacuum deposition of barrier layers directly onto OLED devices:
In R2R production, a separate roll of thin-film barrier could be affixed to an in-process roll of OLED panels, whereas in the alternative, thin-film encapsulation would likely have to be integrated with a single-roll process stream.  Assuming that laminatable barrier films can be manufactured with the required performance, and assuming that adequate processes for lamination (and edge sealing) can be developed, multiple roll processes would enable greater manufacturing flexibility, and would help to drive OLED encapsulation costs down, which is badly needed to spur long-term growth.

Vacuum deposition is usually a slow process, and it is unlikely that it will be compatible with large-scale, high throughput, R2R processing of OLEDs in the long run.  While today volumes are small enough that inline coating is not a major problem, this will not always be the case. If OLEDs are going to reach their commercial potential over the next decade, throughput will have to be greatly increased. Thus, the ability to purchase an encapsulation film that can be affixed without slowing down the line seems beneficial. 

Defects in the encapsulation film in R2R processes are more easily handled if the barrier film is pre-formed and later laminated.  Of course, this assumes defective sections can be identified; if so, those sections of the roll can simply be skipped or removed during the lamination process.  In contrast, vacuum deposition of multiple layers directly onto completed OLED devices is quite risky.  Defective barriers would mean that entire devices—devices that are very expensive—would have to be scrapped.