e-book readers push the EPD technology

It is not very far away that instead of searching for newspapers in the morning you will have to just switch on your e-book reader. The new gadgets, Amazon's Kindle $ Sony Reader 505, have revived the long under performing e-book readers. These devices has encouraged the use of electronic paper display (EPD) technology.

The EPD displays currently being used are based on electronic "ink" developed by E Ink Corp. The ink used is bi-stable and is very energy efficient. The advantages of EPD displays over LCD displays include the lower requirement of energy and that the reflective surface of the EPD displays makes them readable even in daylight. In future the e-paper displays will be flexible as the EPD technology will use plastic substrates instead of the glass substrates.

EPD screens resolution is rapidly improving. The current generation of e-book readers use active-matrix displays and can offer relatively high resolutions. The Kindle screen displays 167 ppi or pixels per inch, while Seiko Epson Corp. recently showed off a 13.4 inch displaying about 385 ppi, that uses E Ink's electrophoretic ink on a silicon thin-film transistor glass substrate.

A number of consumer products, such as watch dials, cell phones, credit cards, security cards, etc are coming up using the EPD technology. The technology is also being used in instrumentation applications, like the capacity meter on Lexar JumpDrive USB drives, and in signage.

However redrawing an image on an EDP takes longer than it does on an LCD screen. It makes this technology unfeasible for animation. Because EPDs are reflective, signage needs to be illuminated in dark areas. And screen contrast is much lower than it is with backlit LCD screens.

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