The answer is an electric paper display
An electric paper display replicates the look and feel of ink and paper. They are very thin and only require power when an image is requested. An EPD is based on electrophoresis, which is the movement of electrically charged molecules. Instead of emitting light, the electric paper display reflects light like paper and operates on the basis of the motion of dispersed particles in a fluid. This fluid is always under the influence of an electric field.