Imagine a miniature television or computer screen that scrolls out of a pen-sized carrying case. Flexible displays like this are almost on the edge of commercial reality, but several challenges still must be overcome in making high-performance thin films that bend but don't break.
There are several different flexible display technologies, but only a few can provide full-color video. LCDs, which are popular for flat screen TVs, require a back light and do not work well when flexed, so a lot of attention is now on organic light emitting diodes (OLEDs). When a voltage is applied across these materials, they emit light over a wide range of colors depending on the organic compounds used. Already one can find flat screen TVs on the market that are constructed from a thin layer of OLEDs on top of a rigid glass support. These displays are faster and have higher contrast than LCDs. What's more, they don't have to be kept rigid, as a few small prototypes have shown. "The flexible display is a killer application for OLEDs," says Ruiqing Ma of Universal Display Corporation.
AVS 55th International Symposium this month in Boston, Ma will be presenting some of the challenges faced in developing the thin films that make up a flexible OLED display. In particular, he will describe the thin metal foils that his group uses to provide a substrate for the tiny transistors that feed electricity to the OLED layer. He will also talk about the preparation of thin, transparent barriers that can keep water and oxygen from rapidly degrading the OLED material.
As testament to their work, Ma and his collaborators have recently succeeded in making the world's thinnest OLED flexible display. Less than 50 microns thick (half that of normal printer paper), this rudimentary prototype works even when rolled around a five-millimeter-wide cylinder.
Ma's talk, "Thin Film Challenges for Flexible Displays and Electronics" is at 2:00 p.m. on Thursday, October 23, 2008, in Room 302 of the Hynes Convention Center.