Patent ID: 7435986

Claim:
A system for detecting defects in a light-management film, the film having a first side and a second side, comprising: first and second light sources configured to emit light simultaneously onto the first and second sides, respectively, of a portion of the film; a first camera disposed adjacent the first side of the film proximate the first light source that receives transmissive and reflected light from the film and generates a first plurality of digital images of the film covering a first region of the film to a second region of the film as the film moves in an axial direction; third and fourth light sources configured to emit light onto the first and second sides, respectively, of the film, the third light source emitting light during a first predetermined time period when the fourth light source is not emitting light, the fourth light source emitting light during a second predetermined time period after the first predetermined time period when the third light source is not emitting light; a second camera disposed adjacent the second side of the film proximate the fourth light source that receives either transmissive or reflected light from the film and generates a second plurality of digital images of the film covering the first region of the film to the second region of the film as the film moves in the axial direction; and a signal-processing device operably coupled to the first and second cameras configured to detect the at least one defect in the film based on the first and second plurality of digital images, the signal processing device further configured to indicate that a repeating defect was detected based on the at least one defect being reproduced at predetermined intervals in the film.