Electrophoretic material, electrophoresis display device, and electronic apparatus

1. An electrophoretic material, wherein

particles are dispersed in a solvent, volume, which is obtained by dividing a volume of the solvent by a total number of particles, is called free volume, and a radius of a spherical space, which is occupied by sum of an average volume of the particles and the free volume, is called a free volume radius;

the particles include at least first particles which are charged with a first polarity and second particles which are charged with a second polarity, an average radius of the first particles is called a first particle average radius, and an average radius of the second particles is called a second particle average radius;

the first particle average radius is greater than the second particle average radius;

a difference between the free volume radius and the first particle average radius is greater than the second particle average radius; and

an electric charge amount of the second particles is greater than an electric charge amount of first particles.

2. The electrophoretic material according to claim 1 ,

wherein surfaces of the second particles are coated with polymer molecules which include a functional group having the second polarity.

3. An electrophoresis display device comprising:

the electrophoretic material according to claim 2 .

4. An electronic apparatus comprising:

the electrophoresis display device according to claim 3 .

5. The electrophoretic material according to claim 1 ,

wherein surfaces of the first particles and the second particles are coated with non-polarity polymer molecules, and

wherein a coat ratio due to the non-polarity polymer molecules on the surfaces of the first particles is greater than a coat ratio due to the non-polarity polymer molecules on the surfaces of the second particles.

6. An electrophoresis display device comprising:

the electrophoretic material according to claim 5 .

7. The electrophoretic material according to claim 1 ,

wherein the first particles have white color, and the second particles have color which is different from the white color.

8. The electrophoretic material according to claim 7 ,

wherein a volume concentration of the first particles is greater than a volume concentration of the second particles.

9. An electrophoresis display device comprising:

the electrophoretic material according to claim 8 .

10. An electrophoresis display device comprising:

the electrophoretic material according to claim 7 .

11. The electrophoretic material according to claim 7 ,

wherein a ratio of a refractive index of the first particles to a refractive index of the solvent is greater than 1, and

wherein the first particle average radius is in a range which is equal to or greater than 0.05 μm and equal to or less than 0.4 μm.

12. The electrophoretic material according to claim 11 ,

wherein the first particle average radius is in a range which is equal to or greater than 0.1 μm and equal to or less than 0.15 μm.

13. An electrophoresis display device comprising:

the electrophoretic material according to claim 11 .

14. An electrophoresis display device comprising:

the electrophoretic material according to claim 12 .

15. The electrophoretic material according to claim 7 ,

wherein the first particles are resin which includes an optical interface therein.

16. The electrophoretic material according to claim 15 ,

wherein the first particles include gaps therein.

17. An electrophoresis display device comprising:

the electrophoretic material according to claim 16 .

18. An electrophoresis display device comprising:

the electrophoretic material according to claim 15 .

19. An electrophoresis display device comprising:

the electrophoretic material according to claim 1 .

20. An electronic apparatus comprising:

the electrophoresis display device according to claim 19 .