Optical glass, preform for press molding and optical element
AssigneeHoya Corporation
InventorsYasuhiro Fujiwara, Xuelu Zou
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Abstract
An optical glass has optical constants represented by a refractive index (nd) of 1.46 to 1.58 and an Abbe's number (νd) of 65 to 74, has excellent hot preform shapeability, low softenability and excellent climate resistance, and comprises, by mol %, 45 to 65% of P2O5, 8 to 19% of Al2O3, 5 to 30% of MgO, 1 to 25% of a total of Li2O, Na2O and K2O, 0 to 16% of B2O3, 0 to 25% of ZnO, 0 to 25% of CaO, 0 to 25% of SrO, 0 to 30% of BaO, 0 to 10% of La2O3, 0 to 10% of Gd2O3, 0 to 10% of Y2O3, 0 to 10% of Yb2O3 and 0 to 10% of Lu2O3, and the total content of the above components of the optical glass is at least 95%.
Claims15
A press-moldable preform which is formed of an optical glass having a refractive index (nd) of 1.46 to 1.58 and an Abbe's number (νd) of 65 to 74, and comprising, by mol %, 45 to 65% of P2O5, 12 to 19% of Al2O3, 5 to 30% of MgO, 1 to 25% of a total of Li2O, Na2O and K2O, 0.5 to 16% of B2O3, 0 to 25% of ZnO, 0 to 25% of CaO, 0 to 25% of SrO, 0 to 30% of BaO, 0 to 10% of La2O3, 0 to 10% of Gd2O3, 0 to 10% of Y2O3, 0 to 10% of Yb2O3 and 0 to 10% of Lu2O3, the total content of said components being at least 95% and contains no SiO2.
A press-moldable preform which is formed of an optical glass having a refractive index (nd) of 1.46 to 1.58 and an Abbe's number (νd) of 65 to 74, and comprising, by mol %, 45 to 65% of P2O5, 12 to 19% of Al2O3, 5 to 30% of MgO, 1 to 25% of a total of Li2O, Na2O and K2O, 0.5 to 16% of B2O3, 0 to 25% of ZnO, 0 to 25% of CaO, 0 to 25% of SrO, 0 to 30% of BaO, 0 to 10% of La2O3, 0 to 10% of Gd2O3, 0 to 10% of Y2O3, 0 to 10% of Yb2O3 and 0 to 10% of Lu2O3, the total content of said components being at least 95% and containing no SiO2, the optical glass having climate resistance represented by the ratio of intensity of scattered light to intensity of transmitted light (scattered light intensity/transmitted light intensity) that is 0.08 or less when one of optically polished surfaces of a sample formed of said optical glass is exposed to white light after the sample is held in air having a temperature of 65° C. and a relative humidity of 90% for 1 week, the two optically polished surfaces being in parallel with each other.
A press-moldable preform which is obtained by shaping a molten glass having a weight and is formed of a glass containing P2O5 and having said weight,
- said glass being an optical glass containing, by mol %, 8 to 19% of Al2O3, 5 to 30% of MgO and 1 to 25% of a total of Li2O, Na2O and K2O and containing no SiO2 and having a refractive index (nd) of 1.46 to 1.58 and an Abbe's number (νd) of 65 to 74.
A process of shaping a molten glass having a weight into a press-moldable preform formed of a glass containing P2O5 and having said weight,
- the process using, as said glass, an optical glass containing, by mol %, 8 to 19% of Al2O3, 5 to 30% of MgO and 1 to 25% of a total of Li2O, Na2O and K2O and no SiO2 and having a refractive index (nd) of 1.46 to 1.58 and an Abbe's number (νd) of 65 to 74.
Dependencies are inferred from the claim text.