| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical glass which can correct the chromatic aberration of a lens highly precisely while its Abbe number lies within a desired range, and to obtain a preform and an optical element using the optical glass. SOLUTION: The optical glass comprises, to the whole mass of the glass in a composition expressed in terms of oxide, by mass, a TiO<SB>2</SB>component of 5.0 to 55.0%, has a partial dispersion ratio [θg, F] of 0.6 to 0.68 and an Abbe number (ν<SB>d</SB>) of 13 to 27. The preform and optical element are composed of the optical glass. COPYRIGHT: (C)2010,JPO&INPIT |
