From my point of view,current e-ink displays have not really improved significantly in terms of resolution and refreshing speed. Where are the current difficulties with the technology?
I remember the difficulty of making larger, highly monodisperse SiO2/polymer particle spheres in the end of the 90s. But I believe this problem was overcome long ago.
So is it the electronic/particle interface that is problematic e.g. size of "pixels"/sphere clusters?