How does e ink work?

Many small "microcapsules" are attached to the surface of the e-ink screen, which encapsulate black particles with negative charge and white particles with positive charge. By changing the charge, the particles of different colors are arranged in an orderly manner, thus presenting a black-and-white visual effect, as shown in Figure 1.  

Figure 1

Power saving is a major feature of e-books. After the text is refreshed, it will stay on the screen for a long time. The battery can be removed when reading.  In other words, e-books don't consume power while being read, but only when turning pages to refresh, so the battery life will be long.  

To the naked eye, e-ink looks like a bottle of ordinary ink, but there are millions of tiny microcapsules suspended in the liquid.  Inside each capsule is a mixture of dye and pigment chips, tiny chips that can be electrically charged.  To see the e-ink microcapsule, think of it as a clear plastic water balloon.  The water balloon contains dozens of ping-pong balls and is filled not with air but with paint water.  If we look at the water ball from the top, we can see many white ping-pong balls suspended in the liquid, so the water ball looks white.  When you look at it from the bottom, all you see is painted water, so it looks black.  If you put thousands of water balloons in a container and move them between the top and bottom of the ball, you can see the container change color;  That's how e ink works;  The water balloons are actually 100 micron wide microcapsules.  In one square inch, it contains about 100,000 microcapsules.  If you print e-ink on a page, a period contains more than 30 microcapsules.