An e-paper display, or electronic paper display, is a type of power-efficient electronic screen that resembles paper. Unlike LCDs or OLED and AMOLED displays, electronic paper screens reflect light rather than emitting it, just like regular paper.
The e-ink screen is formed of millions of microscopic ink capsules filled with a suspended clear fluid (liquid polymer) and placed between two thin-film sheets with electrodes on both sides. Typically, these capsules contain negatively charged black pigments and positively charged white pigments that render grayscale images. Although some e-ink displays contain colored pigments, these aren't common.
The electric charge applied to the electrodes makes particles move inside the capsule, forming black or white pixels. If there's no electric charge, the image stays the same – this is why keeping an e-paper display on with the same image requires very little energy.
E-paper displays are versatile and well-suited for several industries. In addition to low power consumption, these displays are lightweight, have wide viewing angles, and cause less digital eye strain. Not surprisingly, some smartphone manufacturers are implementing secondary e-paper screens. These power-efficient displays are also popular options for wearables and smart home devices. Nevertheless, e-paper displays are most prevalent within the e-book reader industry, which employs e-ink displays almost exclusively.