E-paper gets faster and brighter

A new version of the image layer used in most recent e-books and flexible displays switches twice as fast and is 20 per cent brighter, says developer E-Ink.

The layer, branded Vizplex, will also be available in an expanded range of sizes between 1.9in and 9.7in. It also offers eight levels of greyscale – twice as many as the previous generation – and has a reflectance of 40 per cent, compared to a maximum 35 per cent.

E-Ink technology, the most successful form of epaper to date, uses microcapsules of a fluid containing positively-charged white and negatively-charged black pigment in suspension.

It is driven by an active-matrix layer similar to that used on LCD panels, but unlike those it does not require backlighting and does not require power to maintain an image, and so is far easier on batteries.

But it is very sluggish compared with an LCD. Vizplex switches in 0.74 seconds, compared with 1.2 seconds with the previous generation which is slow even for an e-book on which you are simply turning pages.

LCD panels by contrast switch in less than a hundredth of a second and of course support full colour, which is not yet available on flexible screens.

Taiwan manufacturer Primeview International has built screens using Vizplex. Philips spin-off Polymer Vision uses earlier E-Ink image layers, providing a driver matrix using polymer transistors, but could not say today whether it will use Vizplex.

It has teamed up with Britain's Inmos to build a flexible-screen plant at Southampton. Inmos will demonstrate products at the Flexible Displays show in California on 21 June 2007.

There is huge interest in flexible displays because they have the potential to revolutionise the design of mobile devices. There are concept models on E-Ink's site of pen-sized books with scroll-out screens. But technology has a long way to go to match real paper in terms of texture and brightness.