Film-based lightguide with extended coupling lightguide region

A film-based lightguide comprising:

• a film including a body having lateral edges opposing each other in a width direction, a first surface, and a second surface opposing the first surface in a thickness direction of the film orthogonal to the width direction;
• a light emitting region of the film defined by a plurality of light extracting features;
• a plurality of coupling lightguides in a form of strips arrayed in an array direction and extended from the body of the film in an extended direction perpendicular to the thickness direction and perpendicular to the array direction of the coupling lightguides, the plurality of coupling lightguides folded in a direction orthogonal to the extended direction along a fold line including fold points at which the plurality of coupling lightguide begin to fold such that light input ends of the plurality of light guides are stacked;
• a light mixing region of the film positioned along the film between the plurality of coupling lightguides and the light emitting region;
• and
• an extended coupling lightguide region of the coupling lightguides between the fold line and the light mixing region where the coupling lightguides are not folded,
• wherein an average length of the plurality of coupling lightguides in the extended coupling lightguide region in the extended direction is greater than 1.5 times an average length of the light mixing region between the plurality of coupling lightguides and the light emitting region.

A film-based lightguide comprising:

• a film including a body having lateral edges opposing each other in a width direction, a first surface, and a second surface opposing the first surface in a thickness direction of the film orthogonal to the width direction;
• a light emitting region of the film defined by a plurality of light extracting features;
• a plurality of coupling lightguides in a form of strips arrayed in an array direction and extended from the body of the film in an extended direction perpendicular to the thickness direction and perpendicular to the array direction of the coupling lightguides, the plurality of coupling lightguides folded in a direction orthogonal to the extended direction along a fold line including fold points at which the plurality of coupling lightguides begin to fold such that light input ends of the plurality of light guides are stacked;
• a light mixing region of the film positioned along the film between the plurality of coupling lightguides and the light emitting region;
• and
• an extended coupling lightguide region of the coupling lightguides between the fold line and the light mixing region where the plurality of coupling lightguides are not folded,
• wherein for one or more of the plurality of coupling lightguides, a length along a coupling lightguide between the fold line and a light input end of the coupling lightguide is less than a length of the coupling lightguide in the extended coupling lightguide region in the extended direction.