| 摘要 |
1532343 Monitoring coatings on optical guides WESTERN ELECTRIC CO Inc 9 May 1977 [12 May 1976] 19316/77 Heading G1A [Also in Division G2] The concentricity and uniformity of a transparent coating on a transparent fibre or rod-like element are monitored by directing light beams at first and second angles at the fibre and comparing the backscattered light patterns. An oscillating beam of light is provided by mirror 203 and a laser (He-Ne) or LED 201, and split at 204 to provide two beams incident on an optical fibre 205 being manufactured. Backscattered patterns are formed in the plane of screens 206, 209. These screens may be observed for comparison of the patterns which have intensity distributions of the form shown in Fig. 6, but for retroactive control on the coating applicator position, Fig. 23 (not shown), scanning diode arrays or vidicons analyze the patterns and provide suitable control signals dependent on coating position errors. This apparatus also includes a display of the difference(s) between the main peak spacings of the two patterns, and can indicate a completely deformed coating. In another embodiment, the same beam provides the two angles of incidence when the fibre is rotated.
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