The secret to building an inexpensive flexible computer display is not in the core components of the displays themselves. It's in the material those components are mounted on.
The fundamental elements of e-ink and OLED displays are small enough that they won't break if laid down on flexible backing. The problem, according to Janglin Chen of Taiwanese government-funded research lab ITRI, is the backing itself. The substrate the components are mounted onto has to have certain physical properties, especially during the manufacturing process. To date, the primary material on which displays have been layered has been glass, which meets the needs: it's rigid, transparent, and reliable.
ITRI has found a way, though, to create a display backing material that is all these things during manufacture, but becomes flexible when the building is finished. It's a polymer material that can be sprayed onto a glass backing and that maintains its properties (it doesn't discolor, for example) while the rest of the display is being deposited and built up on top of it. When the displays are done, they can be peeled right off the glass.
In addition to the polymer substrate, ITRI also had to develop a "release material" that's sprayed down on the glass before the polymer, so the final product can peel off without tearing or sticking. Think cooking oil and crepes.
The big advantage to this process, Chen says, is that existing fabrication plants can be used to make flexible panels. Aside from spraying on the chemicals to coat the glass with high-tech Pam and the polymer substrate, and the post-manufacture removal of the display from the glass, the process is the same as making a rigid display.
ITRI has signed at least one non-exclusive deal with a Taiwanese company that makes black-and-white e-readers, and Chen expects the first flexible panel using ITRI technology to be in a consumer product next year. Color displays based on OLED technology are likely after that. E-ink and OLEDs lend themselves well to working on flexible backing, Chen says. Traditional LCDs, which require separate lighting components and filters, do not. The sole existing color e-reader, the new Barnes and Noble Nook Color, uses traditional LCD technology. All current black-and-white e-readers, like the Amazon Kindle, use e-ink displays built up on traditional glass substrates.
The flexible technology isn't limited to displays. ITRI's technology can be used for touch panels (on top of displays, or separately) and for sensor technology. And, I assume, for solar cells, although that's a somewhat challenging market.
I talked with Chen a bit about the market for flexible panels. It's a science-fiction dream to have a foldable or rollable e-book or phone, but there's more to the market than a little flexibility. Chen notes that removing the glass back-plane from a display makes it safer, more durable, and lighter than a traditional display. This is good for low-end products and for devices that end up in the hands of children. And while the ITRI process is not yet less expensive than current display-building technologies, the raw materials do cost less, as the backing glass is reused after every screen is made, instead of getting shipped with it.
But the real flexibility is what this could allow gadget designers to think up. "We're trying to break the glass dimension and give it back to the designer," Chen says.
Source: CNET
