| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide optical glass which has a low Abbe number (ν<SB POS="POST">d</SB>) even though the refractive index (n<SB POS="POST">d</SB>) thereof is within a desired range, and which is highly transparent to visible light, and in which devitrification and clouding hardly occur upon production and working of the glass, and from which a preform material and an optical element are easily produced by polishing, and to provide an optical element. <P>SOLUTION: The optical glass includes, in mass% based on the total mass of the glass in terms of oxides, 5.0 to 40.0% of a P<SB POS="POST">2</SB>O<SB POS="POST">5</SB>component, and 10.0 to 60.0% of an Nb<SB POS="POST">2</SB>O<SB POS="POST">5</SB>component. In the optical glass, the wavelength (λ<SB POS="POST">70</SB>) at which spectral transmittance shows 70% is at most 500 nm, and the optical glass has a liquid phase temperature of 500 to 1,200°C. Further, the optical element is composed of the optical glass as a matrix. <P>COPYRIGHT: (C)2012,JPO&INPIT |
