Organic Sheet-Image Scanner

Organic Sheet-Image Scanner: The image shows a large-area, flexible, and lightweight sheet image scanner consisting of organic transistors and organic photodiodes, which is placed on a business card under ambient light for capturing an image of the card. The sheet has no optical or mechanical parts.

Organic, or carbon-based, semiconductors don't offer the high performance of their inorganic silicon cousins, but they can be fabricated much more cheaply and are better-suited for use with large-area, flexible plastic substrates. Here, each cell consists of an organic transistor and organic photodetector, with an effective sensing area of 50x50 µm2. The entire imager has an effective sensing area of two inches and resolution of 36 dots per inch (dpi), with the potential to go up to 250 dpi.

The photodetectors distinguish between black and white by sensing the difference in reflected light from black and white parts of an image. The thin-film pentacene transistors have 18-micron channel lengths and electron mobilities of 0.7 cm2/Vs, impressive numbers for an organic device. (Paper #15.1 "A Large-Area, Flexible and Lightweight Sheet Image Scanner Integrated With Organic Field-Effect Transistors and Organic Photodiodes," T. Someya et al, University of Tokyo)

©2004 by the IEEE http://www.ieee.org