| 摘要 |
1,242,364. Optical glass. CARL-ZEISSSTIFTUNG, [trading as JENAER GLASWERKSCHOTT & GEN.]. 7 April, 1970 [11 April, 1969], No. 16442/70. Heading C1M. An optical glass consists of (in weight per cent): where (f) to (t) do not exceed 25% of the glass. Component (u) may be chosen from CaF 2 , BeF 2 and MgF 2 , or may be an alkali metal-alkaline earth metal silicofluoride, e.g. Na 2 Ca(SiF 6 ) 2 . The glass preferably has <SP>n</SP>d>1À54, and vd<66.
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