Patent ID: 6038021
Filing Date: 2000-03-14
Classification: G01B,G01N

Abstract:
An on-line system for real-time monitoring at least one characteristic of a material selected from a group consisting of (i) denier, (ii) density, (iii) viscosity, (iv) crystalline structure, (v) dye site, (vi) color, (vii) color variation, and (viii) interlace node occurrence, the system comprising:a light source that emits collimated light synchronously in response to a drive signal;a planar array that includes at least a first light detector and an identical second light detector, said array being closely spaced apart from said source permitting said material to pass therebetween such that at least a fraction of light received by said second light detector has passed through said material; anda synchronously optically coupled feedback circuit, having an input coupled to receive from one of said light detectors a signal synchronized in phase and frequency to said drive signal, said feedback circuit outputting said drive signal to said light source;wherein an output signal from said second light detector is used to monitor said at least one characteristic of said material.