| 摘要 |
609,660. Glass. KODAK, Ltd. March 20, 1946, No. 8581. Convention date, March 27, 1945. [Class 56] An optical glass having an index of refraction for the D-line between 1.505 and 1.530 and an AbbÚ value between 67 and 72 comprises as its predominant constituents BeO, B 2 O 3 and P 2 O 5 . In particular, the BeO may be present in 15-25 parts by weight, the B 2 O 3 in 2- 20 parts and the P 2 O 5 in 65-85 parts. The glass may be prepared by fusing the products obtained by dissolving BeO in an aqueous solution of phosphoric and boric acids and evaporating to dryness. Alternatively, the product obtained by dissolving BeO in aqueous phosphoric acid and evaporating to dryness may be mixed with powdered B 2 O 3 and the mixture fused. The fusing may be carried out in unglazed porcelain crucibles as the batch attacks platinum.
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