Nippon Electric Glass Co., Ltd.

Yoko Usui

Fumio Sato

Takahiro Matano

The invention provides an optical glass for press molding which can satisfy all of the following requirements: (1) it contains no environmentally undesirable components; (2) it can easily achieve a low glass transition point; (3) it has a high refractive index and high dispersion; (4) it can easily provide a glass having an excellent visible light transmittance; and (5) it has excellent resistance to devitrification during preparation of a preform. The optical glass for press molding has a refractive index nd of 1.925 or more, an Abbe's number &#x3bd;d of 10 to 30, and a glass composition, in % by mass, of 20 to 80% BiO, 10 to 30% BO, and 0 to 5.5% GeOand is substantially free of lead component, arsenic component, and F component.

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Otsu, Japan

Yoko Usui