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Some of you, like me, may have walked into a bookshop recently or an electronics superstore perhaps and noticed a new section featuring the plethora of e-book readers that have come into the market. If you pick up one of these and play around with it, the first thing that will probably strike you as different is how 'paper like' the text display appears. Well you are looking at Electronic Ink or e-ink.

Yes, that display on the e-book reader is not just a cool clever LCD or LED type display. It is an entirely different type of display technology made from ink as we have known it for centuries - liquid filled in bottles!

With the advent of LCD displays and OLEDs, the fear was that paper books would go away and be replaced by flashy displays. But the invention of e-ink turns the tables back to those who favour a paper like medium for reading.

Working of e-ink: What goes on inside a micro-capsule. E-ink has millions of such micro-capsules.

How does e-ink work?

Currently there are at least two companies actively researching and patenting this type of ink namely E Ink and Xerox. While there are differences in their approach, the general idea is that e-ink is a liquid composed of millions of micro-capsules. Each capsule is filled with a coloured liquid and a tiny amount of white pigment, which carries an electronic charge. When an external electronic charge opposite to the one on the pigment is applied to the surface of the capsule facing the display, it attracts the pigment and the pigment moves toward the display making the capsule appear white on the display. When an electronic charge identical to the one on the pigment is applied to the surface of the capsule facing the display, it repels the pigment away from the display and the surface of the capsule appears to be coloured on the display. So parts of the display can change colour depending on the charge applied in that region. The fact that these micro-capsules are suspended in liquid means they can be printed onto sheets of paper or other medium just like ordinary ink to make e-paper. Once the entire sheet is covered in e-ink, electronics are required to apply the necessary charge to form words and pictures. Of course the electronics can be programmed to change the words and pictures by pressing a button and this is how these e-book readers work.

Advantages and drawbacks of E-Ink

To start with the advantage is that the display looks like paper and the e-ink looks like ink to the eye. The digital bling is present but is not in your face. The second is that this type of display requires power only when changing the display and extremely low (near zero) power levels to keep the pigments in place. Which means e-ink display equipped devices can run for longer or use smaller batteries. The third advantage is that since the medium is liquid and ink like, it can be printed using traditional methods onto traditional media making the number of uses of this type of display versatile, like a writing pad where the e-ink polarizing medium can be an external pen rather than the media on which the ink is applied.

Ofcourse there are drawbacks. The main one is that at this stage this is largely a black and white or monochrome display. The second is that while the ink can itself be printed onto any compatible medium, the medium used may not be suitable for the accompanying electronics that polarize the display. Remember e-ink does not work by itself and requires accompanying electronics and battery power that will correctly polarise the ink to display information and the electronics are not yet at a stage where they can be embedded into a thin piece of paper on large scales. Finally, images on an e-ink display cannot be refreshed quickly meaning smooth animations or graphic effects are not possible on an e-ink display.

In conclusion

The drawbacks haven't put off the electronics enthusiasts and manufacturers have come up with simple uses of this technology at this stage, like e-books and electronic notepads. These devices may not inspire us much because they look very identical to other electronics gadgets we are used to seeing, but the technology is in there and it is working. However the idea in the long run is to make the electronics discreet enough to not be noticeable at all and all one buys is a hardbound e-book in a book store, like in the good old days, the only difference is that you can press a button and the pages transform to become the book you would like to read.


J.K. Rowling when writing Harry Potter may have imagined the Daily Prophet newspaper changing its news during the day via magic and Tom Riddles Diary talking back to the writer through its pages, but that magic is well within our reach and may be accomplished by e-ink and e-paper in the distant future.