CPC G09G 3/344 (2013.01) [C09B 67/0013 (2013.01); G02F 1/167 (2013.01); G02F 1/1685 (2019.01); G09G 3/2003 (2013.01); G02F 2001/1678 (2013.01); G09G 2300/0452 (2013.01); G09G 2310/068 (2013.01)] | 15 Claims |
1. An electrophoretic medium comprising:
(a) a fluid;
(b) a plurality of first and a plurality of second particles dispersed in the fluid, wherein the first and second particles each have polymer coatings such that a volume fraction of polymer for the first and second particles is at least 25 percent of a volume of the particle, wherein the first and second particles bear charges of opposite polarity, and wherein the first particle is a light-scattering particle and the second particle is a non-light scattering particle and has one of the subtractive primary colors;
(c) a plurality of third and a plurality of fourth particles dispersed in the fluid, wherein the third and fourth particles either have no polymer shell, or the third and fourth particles each have a polymer shell such that a volume fraction of polymer for the third and fourth particles does not exceed 15 percent of the volume of the particle, wherein the third and fourth particles bear charges of opposite polarity, and wherein the third and fourth particles are non-light scattering particles and each has a subtractive primary color different from each other and different from the second particles;
wherein the electric field required to separate an aggregate formed by the third and the fourth types of particles is greater than the electric field required to separate an aggregate formed from any other two types of particles in the fluid.
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