Title:
OPTICAL GLASS, PREFORM, AND OPTICAL ELEMENT
Document Type and Number:
WIPO Patent Application WO/2019/155755
Kind Code:
A1
Abstract:
Provided is an optical glass which has a low partial dispersion ratio with respect to refractive index, Abbe number (high dispersion) and the like, and of which the relative refractive index has a small temperature coefficient. The optical glass comprises, in mass%: 10.0% to 35.0% of a SiO2 component; 10.0% to 35.0% of a Nb2O5 component; more than 0% and up to 15.0% of a Na2O component; more than 0% and up to 20.0% of a BaO component; more than 5.0% and up to 30.0% of a Rn2O component; and 5.0% to 30.0% of a RO component. The partial dispersion ratio (θg, F) satisfies the following relationship with the Abbe number (νd): (-0.008×νd+0.828)≤(θg, F)≤(-0.008×νd+0.876). The temperature coefficient (40°C to 60°C) of the relative refractive index (589.29nm) is in a range of +6.0×10-6 to -2.0×10-6(°C-1). (In the formula: R is at least one element selected from the group consisting of Mg, Ca, Sr and Ba; and Rn is at least one element selected from the group consisting of Li, Na and K.)
Inventors:
IWASAKI NANA (JP)
Application Number:
PCT/JP2018/045444
Publication Date:
August 15, 2019
Filing Date:
December 11, 2018
Export Citation:
Assignee:
OHARA KK (JP)
International Classes:
G02B1/00; C03C3/062
Domestic Patent References:
| WO2016067921A1 | 2016-05-06 |
Foreign References:
| JP2007169157A | 2007-07-05 | |||
| JPH10265238A | 1998-10-06 | |||
| JP2016222511A | 2016-12-28 | |||
| JP2003192384A | 2003-07-09 |
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