Ultra-thin glass used for full roll-to-roll depos­ition of OLEDs

Ultra-thin glass (UTG) is an excit­ing mater­ial. It exhib­its bene­fi­cial fea­tures known from rigid glass sheets like res­ist­ance against heat, UV-light and many chem­ic­als as well as dimen­sional sta­bil­ity, high gas bar­rier per­form­ance and sur­face smooth­ness. Thanks to the thick­ness of only 200 µm or less, however, it also comes with bene­fits that are sur­pris­ing for glass sub­strates, e.g. bend­ab­il­ity and light weight – approx.
250 g/​m² for 100 µm thick UTG.

Recently, vari­ous smart­phone man­u­fac­tur­ers have star­ted to offer phones with fold­able dis­plays based on UTG. This high-priced applic­a­tion can recoup devel­op­ment costs of the UTG and fin­ance the upscal­ing of pro­duc­tion. In the medium term, this mater­ial should thus also become afford­able for lar­ger dis­plays through to OLED light pan­els or even thin-film solar cells.

A con­sor­tium of indus­trial and research part­ners from Ger­many and Japan has demon­strated the poten­tial of UTG for mass pro­duc­tion by suc­cess­fully set­ting up a pilot line for the man­u­fac­tur­ing of organic light emit­ting diodes (OLEDs). This OLED pilot line is com­pletely real­ized as a roll-to-roll pro­cess. The Japan­ese part­ners organ­ized around the Yamagata Uni­versity and the INOEL research insti­tute con­trib­uted all steps from the man­u­fac­tur­ing of 50 and 100 µm thick UTG over full area depos­ition of trans­par­ent con­duct­ive oxide (TCO) towards struc­tur­ing of TCO by screen prin­ted inks and fur­ther sup­port­ive pro­cess steps. Coils of UTG with struc­tured TCO on top were shipped to Ger­many.

The Ger­man part­ners organ­ized around the Organic Elec­tron­ics Sax­ony cluster and Fraunhofer FEP research insti­tute real­ized glass wind­ing in an exist­ing roll-to-roll OLED coater, trans­par­ent elec­trode evap­or­a­tion, encap­su­la­tion, back-sheet lam­in­a­tion, sep­ar­a­tion of single mod­ules as well as embed­ding the mod­ules into demon­strat­ors.

Within this pub­lic fun­ded pro­ject called „LAOLA – Large Area OLED Light­ing Applic­a­tions“ (Ger­man Fed­eral Min­istry of Edu­ca­tion and Research, fund­ing code 03INT509AC), FHR con­trib­uted the reengi-neer­ing of Fraunhofer’s metal strip OLED coater to handle UTG. Even so the pre­con­di­tions set by the machine were by far not ideal for the new pur­pose, the coater can now reli­ably wind UTG with up to
1 m/​min. Besides the detailed tech­nical exper­i­ence and data gained from this pro­ject, one of the major insights is both simple and cru­cial: Ultra-thin glass may still be brittle, but it is much more robust than expec­ted and ready for being used in pro­duc­tion.

FHR, Marian Böh­ling (CSO):„Ultra-thin glass is an amaz­ing mater­ial. As the price falls, it will become the mater­ial of choice for more and more applic­a­tions. FHR is pre­pared to offer cus­tom­ers the tech­no­logy for coat­ing ultra-thin glass with any type of thin films - whether for sensors, dis­plays, bat­ter­ies, OLEDs, thin-film photo­vol­ta­ics or other applic­a­tions.“

FHR Anla­gen­bau GmbH - The Thin Film Com­pany was foun­ded in 1991 and offers tailor-made vacuum coat­ing sys­tems and sput­ter­ing tar­gets as well as coat­ing and equip­ment ser­vice from a single source.

The close cooper­a­tion with our cus­tom­ers starts with the pro­cess devel­op­ment and con­tin­ues with the devel­op­ment of pilot scale up to mass pro­duc­tion. Our port­fo­lio integ­rates the tech­no­lo­gies sput­ter­ing, evap­or­a­tion, PECVD and ALD into the equip­ment types cluster, inline, roll-to-roll and batch. Based in Ger­many and with sys­tems installed world­wide in vari­ous indus­tries such as semi­con­duct­ors, MEMS, elec­tron­ics, sensor tech­no­logy, optics, photo­vol­ta­ics, etc., we will jointly find vacuum coat­ing solu­tions for our cus­tom­ers.