Document Type and Number:
Japanese Patent JPS5223643
Kind Code:
B1
Abstract:
1,224,169. Thorium-free optical glass. PILKINGTON BROS. Ltd., R. J. PARRY, R. DUNNING, A. FORBER, and G. A. HIGHAM. 6 June, 1968 [26 July, 1967], No. 34419/67. Heading C1M. A thorium-free optical glass contains by weight as the essential ingredients from 37% to 45% of B 2 O 3 , from 45% to 53% of La 2 O 3 , and from 0.5% to 4À5% of Al 2 O 3 , and, as optional ingredients, up to 6% of SiO 2 , up to 3% of CaO, and up to 10% of SrO. The glass preferably contains fluorine in a proportion by weight of up to 1.5%. The optical glasses may have a refractive index between 1À69 and 1À71, and a relative dispersion between 55À25 and 56.5.
Application Number:
JP4622568A
Publication Date:
June 25, 1977
Filing Date:
July 04, 1968
Export Citation:
International Classes:
C03C3/068; B01D11/04; C03C3/15; C03C3/23; (IPC1-7): C03C3/30