IDTechEX recently discussed in a webinar the status of flexible barrier technology for OLED in display, lighting and photovoltaic applications. The company has also recently released a market report on the topic.
The webinar discussed the basic requirements for the encapsulation of OLED devices against moisture and oxygen. There are several approaches to the issue available, including various organic and inorganic coating systems as well as ultra thin glass.
IDTechEX showed the effort companies have been taking to create a viable encapsulation technology via the number of patent publications, as shown in the first chart.
The graph indicates that the maximum number of patents was reached in the 2009 time frame, with a significant drop off in recent years. The key technology companies holding the most patents in this area are Samsung , LG and Fujifilm. While the first two are obviously working on company internal solutions, Fuji seems to favor a film solution that will be open to all OLED makers. 3M is another film maker that is active in this field.
The measured and required goal for all OLED encapsulation methods is in the range of 10-6g/sq.m./day. This is a somewhat awkward measure that basically describes how much water or oxygen is allowed to penetrate per unit of surface area and time. With the long lifetime requirements for all OLED applications, the number is indeed very small and also very difficult to measure.
This kind of barrier performance is easily reached with glass substrates, but organic or inorganic barrier layers seem to have more difficulties reaching this level. Nevertheless, LG and Samsung both seem to have solved this issue not only for rigid displays but also for flexible displays.
IDTechEX sees solutions from Fuji and 3M being able to provide this barrier performance. However, OLED makers other than LG and Samsung still appear to be working on a glass-based rigid OLED display, with a flexible version still in the R&D stage.
The company also provided a market forecast for the expected barrier area needed in coming years. We have to keep in mind that some of this area will be provided by in-line coating systems and not as a discrete film or glass product.
The largest part of the market growth will come from plastic rigid and flexible displays in the coming years. However, most applications are showing some growth, just at a slower rate.
IDTechEX sees 3M leading in the commercialization of barrier films. So far all use of 3M films is being covered by an NDA, while there are still issues with the technology integration. It also sees more activities in the thin glass approach, but not as a short term solution. – Norbert Hildebrand
