US Patent 10935716 Film-based lightguide with bend positioning strips behind an extraction region

A film-based lightguide comprises a major sheet area comprising a light extracting region and a minor sheet area positioned between the major sheet area and an array of strips extended from the minor sheet area. Each strip of the array of strips is bent and stacked such that stacked ends of the array of strips define an input surface. The lightguide further comprises a bend in the minor sheet area that positions the array of strips behind the major sheet area in a thickness direction of the film in the major sheet area. In one embodiment, the bend in the minor sheet area bends the film by an angle of 180 degrees. In another embodiment, the bend in the minor sheet area positions the light input surface behind the major sheet area in the thickness direction of the film in the major sheet area.