Variable angle optical sensing system for determining the orientation of weft threads

摘要: An optical sensing system that detects the angular orientation of weft threads in a moving web textile has sensor array receives light transmitted through from source. The is preferably single monolithic chip includes radial pattern photosensitive areas each generate an electrical signal proportional to total intensity incident on area. are elongated and narrow so shadow thread passing over area will modulate output signal. modulation strongest when generally aligned with Electronic circuitry generates DC associated both magnitude frequency also compares these signals, selects largest one, analog voltage characteristic optionally further feedback circuit responsive selected maximum which controls variable power supply for source switched gain amplifier extremes level. A mounting provides coordinated rotation vary angle incidence beam web.