With their crisp, paper-like screens, e-readers like the Kindle are a pleasure to read on. But how do these E Ink displays actually work, and what makes them different from your phone or laptop screen? We unlock the science behind these ingenious displays and explore why E Ink still hasn't conquered all our screens despite its advantages. What are E Ink displays and how do they work? E Ink displays are a special type of screen technology often used in e-readers like the Amazon Kindle. The technology was originally developed in the 1990s at MIT and is now owned by E Ink Corporation. The screens work using tiny microcapsules filled with positively charged white particles and negatively charged black ones suspended in fluid inside the display. By applying positive or negative electrical charges to different areas of the screen, the white or black particles can be made to rise to the surface, creating the text and images on the display. Unlike LCD and LED displays that use a backlight, E Ink displays reflect light - just like paper. This makes them easier on the eyes for long reading sessions. They also require very little power since they don't need a backlight and only use energy when the image changes. The lack of backlighting also means that they are easier to read under brighter lighting conditions, which isn’t the case with LCD/LED displays at all - legibility actually takes a hit under bright sunlight. How is E Ink different from E Paper? E Ink and E Paper may sound like the same thing, but they actually refer to different display technologies. E Paper is a broad term for any display designed to mimic the appearance of real paper. Meanwhile, E Ink is a specific type of E Paper display that uses millions of tiny microcapsules filled with positively charged white particles and negatively charged black particles suspended in a clear fluid. An excellent example of a device with an E Paper display but not an E Ink display is the Pebble smartwatch. This cool gadget uses a low-power LCD with a reflective layer to look like paper, which is a very different implementation from E Ink. What are the advantages and disadvantages of E Ink displays? E Ink displays have several key advantages that make them well-suited for certain applications. First, they consume very little power compared to LCD and OLED displays. An E Ink display only draws power when the image is changed, meaning it can display a static image for weeks or months without needing a charge. This makes it ideal for e-readers and other devices meant for long battery life. Second, E Ink displays cause less eye strain for the user. The lack of a backlight and the paper-like visual experience mean users can read on an E Ink device for hours without fatigue. The matte surface and high contrast also make them easily readable outdoors and under bright light. However, E Ink displays also have some downsides. The biggest is their slow refresh rate compared to LCD and OLED displays. While improvements have been made, such Ink displays still take much longer to refresh, making them unsuitable for video or animation. E Ink also has limitations on colour and resolution compared to other display technologies. And the niche nature of E Ink manufacturing means the displays remain expensive, especially in larger sizes. This limits their use to mostly e-readers and a handful of other products where their particular advantages outweigh higher cost. Therefore, for the majority of display applications demanding speed, responsiveness and high resolution, LCDs and OLEDs remain superior to E Ink alternatives. But for a subset of use cases valuing long battery life, outdoor visibility and eye comfort, they retain unique benefits over other display tech. What are the uses of E Ink displays? E Ink first hit the scene in the early 2000s and was all the rage among e-readers like the Amazon Kindle, Kobo eReader, and Sony Reader. Folks loved it because the text was super clear even in bright sunlight. You can still find E Ink displays on Kindle and Kobo e-readers today, though other screen tech has taken over much of the e-reader market. E Ink made brief appearances in a few early cell phones before getting replaced by fancier displays. But with its easy reading and lower distraction factor, some startups are exploring E Ink in smartphones. A cool example is the BlackBerry-like Minimal Phone, currently crowdfunding, which aims to cut down screen time and help users focus on communication and productivity. Beyond mobile devices, E Ink is popping up around a few cities on stuff like bus stop displays and walking direction signs. Some restaurants are using E Ink menu boards too. Unlike glossy LCDs that create glare and reflections, such displays feature a matte surface that's more natural-looking and readable at angles and under different lighting.
