Optical glass, precision press-molding preform, process for production thereof, optical element and process for the production thereof
First Claim
1. An optical glass having a refractive index (nd) of at least 1.57 but less than 1.67 and an Abbe'"'"'s number (ν
- d) of over 55 but not more than 65, the optical glass containing B2O3, SiO2, La2O3, Gd2O3, an alkali metal oxide and an alkaline earth metal oxide as essential components, having a B2O3 and SiO2 total content of 52% by weight or more and having an SiO2/B2O3 content ratio of from 0.38 to 1.2.
1 Assignment
0 Petitions
Accused Products
Abstract
An optical glass taking account of meltability and the moldability of a preform, having optical constants including a refractive index (nd) of at least 1.57 but less than 1.67 and an Abbe'"'"'s number (νd) of over 55 but not more than 65, having the property of softening at a low temperature and being suitable as a glass for precision press-molding, the optical glass including an optical glass containing B2O3, SiO2, La2O3, Gd2O3, an alkali metal oxide and an alkaline earth metal oxide as essential components, having a B2O3 and SiO2 total content of 52% by weight or more and having an SiO2/B2O3 content ratio of from 0.38 to 1.2, and an optical glass wherein the relationship of the refractive index (nd) and the Abbe'"'"'s number (νd) satisfies the equation (1),
νd>260−126×nd (1).
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Citations
11 Claims
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1. An optical glass having a refractive index (nd) of at least 1.57 but less than 1.67 and an Abbe'"'"'s number (ν
- d) of over 55 but not more than 65,
the optical glass containing B2O3, SiO2, La2O3, Gd2O3, an alkali metal oxide and an alkaline earth metal oxide as essential components, having a B2O3 and SiO2 total content of 52% by weight or more and having an SiO2/B2O3 content ratio of from 0.38 to 1.2. - View Dependent Claims (2, 3, 5, 6, 7, 8, 9, 10, 11)
- d) of over 55 but not more than 65,
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4. An optical glass having a refractive index (nd) of at least 1.57 but less than 1.67 and an Abbe'"'"'s number (ν
- d) of over 55 but not more than 65, wherein the relationship of the refractive index (nd) and the Abbe'"'"'s number (ν
d) satisfies the equation (1),
ν
d>
260−
126×
nd
(1).
- d) of over 55 but not more than 65, wherein the relationship of the refractive index (nd) and the Abbe'"'"'s number (ν
Specification