| 摘要 |
1468963 Optical filter AGA AB 1 March 1974 [14 March 1973] 9331/74 Heading G2J An optical filter, particularly for protecting a welder's eyes whilst permitting him to see the work is of sandwich construction, the inner part having one or more narrow pass-bands, intermediate parts exterior of the inner part to attenuate the radiation in the pass-band(s) and outer parts. The intermediate and outer parts together function as an antireflectance filter, thus the welder is not distracted by e.g. his own image superimposed on the field of view. The ambient lighting is arranged to consist of, or to contain, light is the pass-band(s) and is exemplified by a sodium lamp. Reference has been directed by the Comptroller to Specification 1308901.
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