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Written by: Michelle Chong
Written on: June 1st, 2011
Tags: electrical engineering, entertainment, lifestyle
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About the Author
Michelle Chong is a junior studying Biomedical Engineering at the University of Southern California. She loves reading and plans to buy an e-reader in the near future.
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Volume XIII Issue II > Books of the Future: the Engineering Behind Electronic Ink Displays
Electronic ink mimics the appearance of ordinary ink on paper. It is currently used in cell phones, signs, and e-readers like the Amazon Kindle. There are many ways to imitate natural ink displays, but the most commonly used method is electrophoretic ink. This ink takes advantage of interactions between computer processors and charged black and white particles. The benefits of electronic ink displays over traditional LCD displays include improved readability, low power use, and flexibility. However, the devices are usually quite specialized, have little touch screen capability, and are less responsive than comparable LCD screen devices. These limitations are areas of current development for electronic ink manufacturers. Electronic ink devices have great potential for future applications, including conservation efforts. They could significantly reduce paper waste and tree consumption by replacing much of the current need for paper. As the field of electronic ink displays evolves, it is important to consider their current uses, the engineering behind the technology, their advantages and limitations, sustainability of the technology, and future development.


“‘But in, you know, the Muggle world, people just stay put in photos.’
‘Do they. What, they don't move at all?’ Ron sounded amazed. ‘Weird!’
Harry stared as Dumbledore sidled back into the picture on his card and gave him a small smile” [1]
Boarding the train to Hogwarts School of Witchcraft and Wizardry, Harry Potter discovers that photos in the wizarding world are not static like they are in the Muggle world. Images move, stirred by magic. Portraits smile and wave; landscapes shift and change over time. For us common Muggles, unfortunately, magic remains an elusive goal. The moving photos described above, however, may in fact be within reach with a relatively new technology called electronic ink. Thanks to this new development, we may soon be able to enjoy animated magazines, newspapers, and other printed material.
In fact, some publications using electronic ink have already hit the shelves. Esquire’s 75th anniversary edition featured the first-ever electronic ink cover in October 2008. Its headline blinked and flashed the words “The 21st century begins now” [2]. The issue is only the first of many that may possibly eliminate much of the current need for paper. Modern e-readers, such as the popular Amazon Kindle, already utilize electronic ink technology. This article dives into the technology that powers the Kindle: the engineering behind electronic ink, its benefits and limitations, its role in sustainability, and future applications.

Current Uses of Electronic Ink

Electronic ink is a technology that mimics the appearance and qualities of ordinary ink on paper, retaining images until electronically changed. It is manufactured by many companies in a variety of ways. The most notable are Xerox and E-Ink, which began developing electronic ink in the mid-1990s. By the early 2000s, products using electronic ink began to enter the market [3].
NotFromUtrecht/Wikim​edia Commons
Figure 1: Third generation Amazon Kindle with an electronic ink display.
Electronic ink can now be found daily in various technologies. It has been used in the screens and keypads of mobile phones such as the Motorola F3 and Samsung Alias 2. It can be seen in various signs, billboards, and retail store pricing labels [4]. The most well-known current use of electronic ink, however, is in the screens of e-readers like the Amazon Kindle or Barnes & Noble Nook (Fig. 1). Amazon has sold an estimated 3 million Kindles, first released in 2007, demonstrating the commercial success of electronic ink [5].

How Does Electronic Ink Work?

There are many ways to make electronic paper displays that mimic the natural appearance of ink on paper, with each method varying by the manufacturing company. Currently, the most commonly used type of electronic ink works through electrophoretic technology. E-Ink, Gyricon, SiPix, and Bridgestone are among the companies that successfully use this method [4].
E Ink
Figure 2: Electronic ink microcapsules consist of tiny negatively and positively charged particles.
Electropho​retic ink takes advantage of different colored, oppositely charged particles moving into view to form patterns. Electrophoresis separates particles by their charge by applying voltage via electrodes; positively charged molecules are attracted to negative voltages, and negatively charged molecules are attracted to positive voltages.The ink itself consists of countless solid microcapsules that have three main components (Fig. 2) [6]:
• Negatively charged black particles
• Positively charged white particles
• Transparent liquid