E-Ink Basics

When talking about the different displays of ereaders and features like backlights, etc., it can be really helpful to have a basic understanding of how the electronic ink (e-ink or eink) technology actually works to better help you understand why some features may or may not be possible on an e-ink display.

Electronic Ink displays used in ereaders are currently produced in greyscale and are comprised of an array of tiny spheres sandwiched between two conductive plates, with each sphere cushioned by oil. Each sphere also contains a darkly dyed oil plus particles of titanium dioxide. Images are formed on the display by creating a charge on either the front plate or the back plate, in order to attract the titanium dioxide particles. When the particles are attracted to the back plate, the sphere will appear dark because the light is absorbed by the darkly colored oil. When the particles are attracted to the front plate, the sphere will appear white because the particles will reflect the light.

To distill it further, it’s a bit like the board game Reversi. A sphere (pixel) is either light side up or dark side up and once it’s set, it stays unless an action is taken on it by the player or charged plate.

Using the eink displays is very kind to battery life because they require the charge to be sent once to display the content but the charge doesn’t have to be maintained after that. This is unlike things like LCD or CRT displays which require continuous power to maintain the displayed information. But this creates a few problems of its own. Eink displays take a longer refresh rate to display a new page and because they work from reflected light (not emitted light), you are looking at the surface of the display. This means that eink displays are not compatible with backlighting. Sorta like a printed book, actually. This technology is also why they are easy to read in even fairly strong sunlight, unlike emitted light displays.


Comments are disallowed for this post.

Comments are closed.


Most Emailed