E Ink is becoming very popular in all manner of electronic devices, especially electronic books like the Kindle and the Sony Reader – but what is it? And what makes it different from usual screen technology?

E Ink, as a technology, really describes a form of electronic paper display (EPD) and emerged from research originally conducted from the MIT Media Lab. E Ink was intended to overcome some of the problems with current display screen technology which typically require a lot of power to operate as they require a light or heat source to be maintained when displaying images.

To get a better feel of how E Ink works imagine a bubble filled with clear fluid. In this bubble are white particles and black particles (thus the term ink), charged positively and negatively, appropriately. Electrodes sit at the top and bottom of this bubble and when they are charged they cause the oppositely charged particles in the bubble to react in unison – either being pulled towards the top electrode or the bottom electrode (it might help to Imagine those experiments with iron filings and magnets from school – the magnet caused the iron filings to stand on end).

This bubble is about the width of a human hair. Millions of these bubbles are arranged into a grid like pattern allowing them to be addressed individually – so they can be programmed to display familiar images.

One of the benefits of E Ink technology like this is that the state of the particles is maintained, for a period, so the white and black particles stay where they were last set – which can reduce the power requirement.

Further Reading

E Ink Corporation