Optical glass, preform for press forming, optical element, and processes for producing these
AssigneeHoya Corporation
InventorMiko Ikenishi
Life of this patent
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Abstract
Provided is a low-dispersion optical glass that is formed of a fluorophosphate glass in which the molar ratio of the content of O2− to the content of P5+, O2−/P5+, is 3.5 or more and that has an Abbe's number (νd) of over 70 or has an F− content of 65 anionic % or more, and the optical glass enables the suppression of the volatilization of a glass component when an optical glass formed of a fluorophosphate glass is produced or when an obtained glass in a molten state is caused to flow out to shape it into a glass shaped material, so that the variation of properties such as a refractive index, etc., involved in the fluctuations of a glass composition and the variation of quality such as the occurrence of striae can be suppressed.
Claims16
-26. (canceled)
An optical glass that has an Abbe's number (νd) of over 70 and that is formed of a fluorophosphate glass having an O2− content/P5+ content molar ratio, O2−/P5+, of 3.50 or more.
A process for the production of an optical glass formed of a fluorophosphate glass, which comprises preparing a raw material batch from raw materials or cullet, melting the raw material batch and then carrying out refining and homogenization,
- the process comprising preparing the raw material batch in which the total O2− content/total P5+ content molar ratio, O2−/P5+, is 3.5 or more and carrying out the melting, refining and homogenization to produce a fluorophosphate glass having an Abbe's number (νd) of over 70.
A process for the production of an optical glass formed of a fluorophosphate glass, which comprises preparing a raw material batch from raw materials or cullet, melting the raw material batch, then carrying out refining and homogenization to prepare a molten glass and shaping said molten glass,
- the process comprising controlling the total O2− content/total P5+ content molar ratio, O2−/P5+, in said raw material batch for decreasing the volatility of said molten glass.
Dependencies are inferred from the claim text.