Electrophoretic device having transparent light state

A light attenuator comprising a plurality of cells, each cell comprising:

• a first substrate including a first light-transmissive electrode;
• a second substrate including a second light-transmissive electrode, the second substrate being spaced apart from the first substrate to define a gap between the first and second substrates;
• an electrophoretic ink including charged particles in a suspending fluid disposed in the gap;
• and
• a non-planar, polymeric structure adjacent the second substrate comprising a plurality of aperiodic microstructures, a surface of the non-planar, polymeric structure extending into the gap between the first and second substrates and creating a non-planar interface with the electrophoretic ink;
• wherein the light attenuator has a first light state in which the charged particles are distributed throughout the suspending fluid and lie in the path of light traversing the cell, thereby attenuating light passing through the light attenuator, and
• a second light state in which the charged particles move adjacent the surface of the non-planar, polymeric structure and are substantially removed from the path of light traversing the cell, thereby transmitting light passing through the light attenuator.