December 2, 2005 – Researchers at the U. of Tokyo have created a flexible Braille display utilizing organic semiconductor devices — plastic actuators driven by an organic field-effect transistor active matrix.
An underlying array of organic pentacene thin-film transistors (TFT) with top-contact geometry was built on polyimide plastic substrates (20-micron channel lengths, and mobilities of 1 sq. cm/Vs). Voltages are fed to actuators fabricated from conductive polymer, moving them upward and pushing attached hemispheres against the underside of the rubber-like surface film, forming bumps in the shape of Braille letters — up to 24 letters on the entire 4x4x0.1cm device can be displayed.
The device consumes about as much power (<1mW) as a cell phone or digital camera. Other potential applications for the technology include e-books, prepaid cards (account balances displayed right on the card), and household appliances.
Researchers hope to improve the display to show up to 576 letters of Braille at a time, with possible commercialization in five or six years, priced at 1000 yen (about US$8).