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Paper Promises Better E-Paper

It is clear that computer displays will someday be thin and flexible enough to roll up, enabled by plastic electronics.

Most prototypes to date have been built using organic light emitting diodes (OLED) on plastic or metal foil substrates. Researchers from Korea Electronics Technology Institute (KETI) have produced electronic paper made from ordinary paper coated with thin layers of plastic electronics.

Paper has the advantage of being light, inexpensive and thermally and mechanically stable during processing. Their method could be used to make roll-up displays of all types, including electronic paper, electronic maps, and advertising displays.

The researchers made the device by coating a sheet of commercial inkjet paper with the plastic parylene to protect the paper from moisture and provide a uniform surface, then applying a second layer of parylene followed by layers of nickel, three types of organic material and a metal top layer.

The top layer is semi-transparent, transmitting more than 75 percent of the light generated beneath it to provide a maximum brightness of 417 candelas per square meter. Computer display brightness values typically range from 150 to 2,000 candelas per square meter.

The prototype device has emitting areas of 10 millimeters by 2 millimeters. The device worked while rolled around a pen with a diameter of 8 millimeters, according to the researchers.

The researchers presented the work at the Society for Information Display (SID) International Symposium in Seattle Washington, May 23 to 28.