Patent ID: 7936277

Claim:
An apparatus for detecting a difference in a width of a strip of material from a desired width, the strip of material having a first edge, a second edge, a first face, and a second face, the apparatus comprising: a light detector; a first fiber optic cable having a first end, a second end, and at least two optical fibers, each having a first end and a second end, and configured to receive light at the first end of the first fiber optic cable; a second fiber optic cable having a first end, a second end, and at least two optical fibers, each having a first end and a second end, and configured to receive light from the second end of the first fiber optic cable and to transmit light to the light detector; and a housing for fixing the second end of the optical fibers of the first fiber optic cable and the second end of the optical fibers of the second fiber optic cable in spaced relationship to each other, wherein the at least two optical fibers of the first fiber optic cable are configured such that light extending from their second ends form light fields spaced apart from each other by a distance such that, if the strip of material is of the desired width, at least a portion of at least one of the light fields can shine on the first face at the first edge simultaneously while at least a portion of another one of the light fields shines on the first face at the second edge of the strip of material.