US Patent 7920314 Variable opacity or translucency of a through-vision panel

A multi-sheet through-vision panel includes a first outer sheet, a second outer sheet, and a middle sheet located between the first and second outer sheets. The first and second outer sheets are superposed with one another. At least one light impairing zone is disposed on at least one of the first and second sheets, as well as the middle sheet. A sliding mechanism slides the middle sheet with respect to the first and second outer sheets so that the light impairing zones are moved between a first and second position. The light impairing zones are superposed with one another when the middle sheet is in the first position, but are in a staggered arrangement when the middle sheet is in the second position.