| 摘要 |
568,272. Colour filters. FRANCE, E., and HODSON, C. F. July 5, 1943, No. 10855. [Class 97 (i)] To enable a colour-blind person to identify the colour of an object there is provided a pair of filters for each colour to be identified, the first member of each pair being a colour and the second member the complement of that colour. The filters may be built up into spectacles, lorgnettes, &c.
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