Patent ID: 9646547
Date: 2017-05-09
CPC Classifications: G02F,G09G

Claim:
1. A display layer having a first, viewing surface and a second surface on the opposed side of the display layer from the first surface, the display layer further comprising an electrophoretic medium sandwiched between two electrodes and comprising a solvent or solvent mixture and high positively charged particles, high negatively charged particles, low positively charged particles, and low negatively charged particles all dispersed in the solvent or solvent mixture, the four types of particles having respectively optical characteristics differing from one another, such that: (a) application between the two electrodes of a high potential difference having a polarity driving the high positively charged particles towards the viewing surface will cause the display layer to display the optical characteristic of the high positively charged particles at the viewing surface; (b) application between the two electrodes of a high potential difference having a polarity driving the high negatively charged particles towards the viewing surface will cause the display layer to display the optical characteristic of the high negatively charged particles at the viewing surface; (c) once the optical characteristic of the high positively charged particles is displayed at the viewing surface, application between the two electrodes of a low potential difference having a polarity driving the low negatively charged particles towards the viewing surface will cause the display layer to display the optical characteristic of the low negatively charged particles at the viewing surface; and (d) once the optical characteristic of the high negatively charged particles is displayed at the viewing surface, application between the two electrodes of a low potential difference having a polarity driving the low positively charged particles towards the viewing surface will cause the display layer to display the optical characteristic of the low positively charged particles at the viewing surface.