Electrically-actuated variable transmission film having very low haze and a visible grid in a clear state

A light attenuator comprising:

• a first transparent substrate;
• a second transparent substrate;
• a first transparent electrode adjacent the first transparent substrate;
• a second transparent electrode adjacent the second transparent substrate,
• a transparent polymer structure disposed between the first transparent electrode and the second transparent electrode, the transparent polymer structure defining a volume between the first transparent electrode and the second transparent electrode;
• and
• an electrophoretic ink disposed in the volume, the electrophoretic ink comprising charged particles dispersed in a transparent fluid,
• wherein the charged particles are responsive to electric fields applied between the first and second transparent electrodes and with the application of electric fields the charged particles move between:
• a first state in which the charged particles are distributed throughout the volume, thereby attenuating light passing through the light attenuator, and
• a second state in which the charged particles are concentrated within locations in the transparent polymer structure, thereby removing the charged particles from the path of light passing through the light attenuator, thereby providing visible transmission between the first and second transparent substrates,
• wherein in the second state, a viewing face of the light attenuator has a dark pattern of locations adjacent transparent areas, the dark pattern and transparent areas being defined by a presence and an absence, respectively, of concentrated charged particles, the dark pattern comprising repeating units of locations of concentrated charged particles, and wherein each repeating unit of the dark pattern has a dimension between 0.3 mm and 3 cm, and a centre-to-centre distance between repeating units between 0.6 mm and 6 cm.