Method and apparatus for optically detecting elongated defects in glass

Claim 1

A METHOD OF DETECTING THE PRESNCE OF DEFECTS IN BODIES OF GLASS IN SHEET AND RIBBON FORM, RESULTING FROM THE INCOMPLETE BLENDING OF VARIOUS GLASS INGREDIENTS FROM ING THE GLASS MELTING AND FINING OPERATIONS, THAT ARE GENERALLY ELONGATED IN ONE DIRECTION AND REFRACT LIGHT, COMPRISING: SCANNING SAID GLASS BY PROJECTING A BEAM OF LIGHT THERETHROUGH, EXAMINING WITH SID BEAM OF LIGHT ONLY INCREMENTAL PORTIONS OF THE GLASS THAT ARE CORRELATED IN DIMENSIONS WITH AND ARE ELONGATED IN THE DIRECTION OF SAID DEFECTS, SAID BEAM BEING REFRACTED BY SAID DEFECTS AND THEREBY INDICATING THE PRESENCE THEREOF; SENSING, IN PROGRESSIVE INCREMENTAL PORTIONS OF SAID GLASS, VARIATIONS IN LIGHT INTENSITY CAUSED BY SAID RFRACTION OF SAID BEAM SO AS TO DETECT THE PRESENCE OF SAID DEFECTS IN SAID GLASS; AND ELECTRICALLY COMPARING THE INTENSITY OF SAID VARIATIONS WITH PREDETERMINED VALUES OF LIGHT INTENSITY TO DETERMINE THE SEVERITY OF SAID DEFECTS.