Ten years ago if you were to make a list of technologies due for an overhaul, books would have been pretty close to the top of the list. The fundamental technology of books has changed very little since ink was first put to paper in the first century BCE. We’ve been able to make higher quality books with remarkable speed, but the technology has still consisted of ink on paper.

That is, until recently.The advent of electronic ink by companies such as E Ink Corp. (a company that has been a leader in popularizing the use of this technology) has given rise to the e-book reader that has changed the way many people read.


Did You Know?
E Ink Corp. is a spin-off of MIT’s Media Lab. This is the same place that has spun off Harmonix (creators of Guitar Hero and Rock Band) and the One Laptop Per Child initiative.

E Ink’s technology is deceptively simple and based on a process known as electrophoresis (an electric current is used to move charged particles). Another technique that is gaining popularity uses electrowetting (an electric current alters the surface tension of liquids).

Electrophorectic Display

Basic drawing of an electrophoretic display. Image courtesy Senarclens, Wikimedia Commons.

With E-readers based on E Ink's technology, each point (or pixel) on a screen is actually a microscopic capsule of liquid full of tiny black and white balls. These capsules are less than a micron wide (a micron is about 1/100th the size of a human hair),which means that more than 100,000 capsules can fit within one square inch of paper. The black and white balls contained within each capsule are negatively charged (black) and positively charged (white). By applying a charge to tiny electrodes found beneath each capsule we can push one specific color of ball to the surface, while pulling the opposite color to the bottom. E-book readers display text by simply making each capsule appear black or white at a specific point.


Did You Know?
Several versions of Amazon’s Kindle (a popular e-book reader) have some very cool “Easter eggs” (hidden features or jokes). For example, pressing Alt, Shift and the M key from the home menu will launch into the classic PC game, Minesweeper!

One significant advantage of e-book readers over LCD tablets is that they tend to have an extremely long battery life. This is because they only draw power when they change what they are displaying. LCD displays must constantly draw power in order to maintain the image on the screen. Once an e-ink capsule is displaying the right color, it will maintain that colour with virtually no power required.


Did You Know?
Many companies are racing to make full colour electronic paper displays. The technology is significantly more complicated than black and white displays, but we’re starting to see full colour e-book readers at places like the Consumer Electronics Show.

As electronic ink becomes cheaper and faster, we are starting to see it popping up in unexpected places like in clothes and on vehicles! The beautiful simplicity of the technology means that the potential is virtually limitless.

Learn More!

This link (PDF) describes the technologies currently used in EPDs (electronic paper displays)

To see a few of the novel uses for e-ink technology, checkout this article in PC Magazine.

How Stuff Works has a very good article on e-ink.

Learn how LCD displays work.

Article first published October 26, 2011

Peter Kublik

Peter is a freelance science writer from Calgary, Alberta. He has been granted several exciting opportunities to share his passion for science outreach and education in the media, most recently during a four month media fellowship with CBC Radio's Calgary morning show, the Eyeopener. Outside of the lab he is an amateur photographer, an avid outdoorsman, and an enthusiastic technophile.

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