Optical glass for molding
AssigneeSumita Optical Glass, Inc.
InventorsMasaaki Otsuka, Yoshinori Yamamoto, Koichi Tsuchiya, Naruhito Sawanobori, Shinobu Nagahama
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Abstract
The present invention provides an optical glass for press molding, in particular, a low softening point glass which contains, in an oxide glass of phosphate type, a durability improving component in addition to glass forming components, and has a weight loss of at most 0.15 weight % in a durability test, and which is represented, in term of elements for making up the glass, by the following chemical composition (mol %): P2O5 32 to 40% Li2O 6 to 21% Na2O 8 to 31% K2O 4 to 22% Al2O3 7.4 to 16% ZnO 0 to 19.6% BaO 0 to 12% and Sum of Li2O + Na2O + K2O 35.1 to 49%.
Claims7
An optical glass having a refractive index (nd) of 1.50 to 1.55, an Abbe number (νd) of 58 to 67, a press molding temperature no greater than 400° C. and a weight loss no greater than 0.15 weight %, which is represented, in term of elements for making up the glass, by the following chemical composition (mol %):
- P2O5 32 to 40% Li2O 6 to 21% Na2O 8 to 31% K2O 4 to 22% Al2O3 7.4 to 16% ZnO 0 to 19.6% BaO 0 to 12% and Sum of Li2O + Na2O + K2O 35.1 to 49%.
An optical glass having a refractive index (nd) of 1.50 to 1.55, an Abbe number (νd) of 58 to 67, a press molding temperature no greater than 400° C. and a weight loss no greater than 0.15 weight %, which is represented, in term of elements for making up the glass, by the following chemical composition (mol %):
- P2O5 32 to 37% Li2O 6 to 19.5% Na2O 12 to 22% K2O 7 to 19% Al2O3 8 to 15% ZnO 1 to 11% BaO 0.5 to 9% and Sum of Li2O + Na2O + K2O 36 to 47.5%.
Dependencies are inferred from the claim text.