Five-particle electrophoretic medium with improved black optical state

A color electrophoretic display comprising:

• a light-transmissive electrode layer at a viewing surface;
• a back electrode layer;
• and
• an electrophoretic medium disposed between the light-transmissive electrode layer and the back electrode layer, the electrophoretic medium comprising:
• a non-polar fluid;
• and
• a multi-pigment particle system comprising five types of charged electrophoretic pigment particles dispersed in the non-polar fluid, the five types of charged electrophoretic pigment particles comprising:
• a first type of particle having a first optical property and a first charge polarity;
• a second type of particle having a second optical property, and having a second charge polarity with a first charge magnitude, said second charge polarity being opposite to the first charge polarity;
• a third type of particle having a third optical property, and having the second charge polarity with a second charge magnitude smaller than the first charge magnitude;
• a fourth type of particle having a fourth optical property, and having the second charge polarity with a third charge magnitude smaller than the second charge magnitude;
• and
• a fifth type of particle having a fifth optical property, and having the second charge polarity with a fourth charge magnitude greater than the first charge magnitude;
• wherein the first type of particle is white, the fifth type of particle is black, and the second, third, and fourth types of particles are each a different one of cyan, magenta, and yellow.