| 摘要 |
PROBLEM TO BE SOLVED: To obtain optical glass where polishing works are easily performed regardless of having a refractive index (n<SB>d</SB>) and an Abbe's number (ν<SB>d</SB>) within their predetermined ranges, an optical element using it and an optical device. SOLUTION: The optical glass contains, in mass%, a B<SB>2</SB>O<SB>3</SB>ingredient of 25.0-40.0%, an La<SB>2</SB>O<SB>3</SB>ingredient of 25.0-48.0%, a Gd<SB>2</SB>O<SB>3</SB>ingredient of 3.0-30.0% and a Y<SB>2</SB>O<SB>3</SB>ingredient of 0.5-30.0% to the total mass of a glass composition in terms of an oxide. The base material of the optical element is the optical glass. In the optical glass, the refractive index of the glass is enhanced, dispersibility is controlled, the wear rate of the glass is enhanced and the devitrification temperature of the glass is suppressed by using the B<SB>2</SB>O<SB>3</SB>ingredient, the La<SB>2</SB>O<SB>3</SB>ingredient, the Gd<SB>2</SB>O<SB>3</SB>ingredient and the Y<SB>2</SB>O<SB>3</SB>ingredient together and by controlling the containing ratios of the B<SB>2</SB>O<SB>3</SB>ingredient, the La<SB>2</SB>O<SB>3</SB>ingredient, the Gd<SB>2</SB>O<SB>3</SB>ingredient and the Y<SB>2</SB>O<SB>3</SB>ingredient within the ranges. COPYRIGHT: (C)2010,JPO&INPIT
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