| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and an instrument for measuring the velocity of yarn, based on the Doppler interference, capable of dispensing with accurate positioning of the yarn with respect to the irradiation region of a light beam. SOLUTION: The problem to be solved is solved by this method of introducing a second light beam 4b into a photodetector 8 without contacting with the yarn 5, in the method of measuring the velocity of the yarn 5 wherein the first coherent light wave 6a interferes with the second coherent light wave 6b, where the first coherent light wave 6a includes a light scattered by the yarn 5, and is a light wave generated from the first light beam 4a projected to the yarn 5, and where the second light wave 6b is a light wave generated from the second light beam 4b, and wherein the velocity of the yarn 5 is found from the Doppler interference between the light waves 6a, 6b in the photodetector 8. COPYRIGHT: (C)2009,JPO&INPIT |
