Electronic ink has been around for quite some time. This technology can be found in Kindle, Nook, and other electronic reading devices. What may surprise you is that the technology behind these eReaders is quickly heading for your credit card in addition to small and large signs. Eink, the company behind most of the electronic ink display (ePaper) technologies, has created a screen that is made up of millions of microcapsules that contain dark and light elements. When presented with a charge, the elements mix and create varying shades across pixels on the screen. The charge required to create an image on these screens is typically far below that of a traditional LCD.
Electronic ink technology is driven by microcapsules. These capsules, containing white and black pigments, are coated on sheets of thick plastic. These sheets are made up to a kilometer in length and kept on rolls. These thin screens, which are cut out of the larger sheets, are roughly 30 microns thick. This means that the screen itself is thinner than some types of paper. Each pixel is backed by dozens of separate capsules that assist in creating a clear image. In fact, the displays can achieve remarkably high definition within a considerably small space.
Once the sheet is cut and prepped, it is given a backing and front-facing protective sheet and shipped to the customer to be applied to their own devices (like a Kindle).
The controlling charge that allows the device to create the desired image on the screen is delivered through two small tabs on the upper and lower part of the screen. Once the charge is delivered, the image is set and can remain on the screen for a very long time with minimal (if any) required current to maintain. This is one reason why the battery life on something as thin as the Kindle can last for weeks, and even months.
An RGBW filter can be applied to the technology to create a color display. Color ePaper displays are actually much thinner than their monochrome counterparts. In addition, color displays require no more energy to power than their black and white counterparts due to a passive technology that creates the color overlay.
To further reduce the required thickness of eReader devices, a plastic backing to the screen could be used as opposed to a popular glass backing. This would also allow for electronic textbooks to be manufactured cheaply, while maintaining a superior durability over glass-based displays. Dropping a plastic-backed eReading device is much less likely to result in breaks than one backed in glass, naturally.
Other applications for electronic ink include signs, credit cards that display your balance, memory sticks with capacity reminders, secondary mobile phone displays, and more. Eink has made great strides in the technology behind electronic ink in recent years, going from a basic technology that provides a better contrast than most newspapers to one with a wide variety of applications where higher-definition displays are needed and battery power is limited. In the next year, Eink expects to ship between 20 and 30 million units, making this its biggest year in terms of sales, thus far.