Protective headgear comprising a curved switchable shutter and comprising multiple antireflective layers

A protective headgear comprising:

• an automatic darkening filter that comprises a curved switchable shutter that exhibits a curvature;
• a front cover plate that exhibits a curvature and that is positioned in front of the shutter;
• and,
• a rear cover plate that exhibits a curvature and that is positioned in rear of the shutter,
• wherein the front and rear cover plates and the shutter define an optical path that electromagnetic radiation can follow to reach the eyes of a wearer of the protective headgear;
• wherein the optical path includes a front air gap of from 0.5 mm to 4 mm between a major rear surface of the front cover plate and a major front surface of the curved switchable shutter, and further includes a rear air gap of from 0.5 mm to 4 mm between a major rear surface of the curved switchable shutter and a major front surface of the rear cover plate,
• and,
• wherein a total of two or three two antireflective layers are disposed on the optical path, including:
• an antireflective layer disposed on the major rear surface of the curved switchable shutter;
• and,
• an antireflective layer disposed on the major front surface of the rear cover plate and/or an antireflective layer disposed on a major rear surface of the rear cover plate,
• and wherein no antireflective layer is present on the major front surface of the curved switchable shutter or on a major front surface or the major rear surface of the front cover plate.