Electrophoresis is the physical mechanism behind electronic paper displays. Millions of tiny microcapsules contain positively charged white pigment and negatively charged black pigment suspended in clear fluid. By applying localized electric fields across the display matrix, the controller forces either the white or black particles to the top of the capsule, creating a persistent image that draws zero power until it needs to change.
Heard on the job
The refresh rate on this reader is slow because the electrophoresis takes a few hundred milliseconds to settle the pigments.