Optical glass
AssigneeKabushiki Kaisha Ohara
InventorKoji Shimizu
Life of this patent
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Abstract
An optical glass comprising SiO2, B2O3 and La2O3 and one or more oxides selected from the group consisting of ZrO2, Nb2O5 and Ta2O5, having a refractive index of 1.83 or over and an Abbe number of 35 or over and being free of F.
Claims24
An optical glass comprising SiO2, in an amount of 9 mass % or below, B2O3 and La2O3 in an amount of 50 mass % or below, Li2O in an amount of 0.5% or over and one or more oxides selected from the group consisting of ZrO2, Nb2O5 and Ta2O5, where the total amount of Gd2O3+Nb2O5 is less than 10 mass %, said optical glass having a refractive index of 1.85 or over and an Abbe number of 35 or over, having a glass transition temperature (Tg) of 630° C. or below and being free of F.
An optical glass having a glass transition temperature (Tg) of 630° C. or below comprising, in mass % calculated on oxide basis,
- SiO2
- 2-9%
- and/or
- B2O3
- 8.0-less than 18% and/or
- La2O3
- 33-50%
- and/or
- Gd2O3
- 3-20%
- and/or
- ZrO2
- 4.5-7%
- and/or
- Nb2O5
- 0.1-3%
- and/or
- Ta2O5
- 15-25%
- where a total amount of Ta2O5+Nb2O5 is 17-28% and
- Li2O
- 0-3%
- and/or
- ZnO
- 0-10%
- and/or
- RO
- 0-5%
- where R is one or more elements selected from the group consisting of Mg, Ca, Sr and Ba and/or
- Sb2O3
- 0-1%
- being free of F and having a refractive index within a range from 1.88 to 1.90 and comprising WO3 in an amount of less than 0.5% in mass % on oxide basis.
An optical glass having a glass transition temperature (Tg) of 630° C. or below comprising, in mass % calculated on oxide basis,
- SiO2
- 3-9%
- B2O3
- 9.5-less than 18%
- La2O3
- 33-45%
- Gd2O3
- 3-18%
- ZrO2
- 5-7%
- Nb2O5
- 0.1-3% and
- Ta2O5
- 15-25%
- where a total amount of Ta2O5+Nb2O5 is 16-28% and
- Li2O
- 0-3%
- and/or
- ZnO
- 0-10%
- and/or
- RO
- 0-5%
- where R is one or more elements selected from the group consisting of Mg, Ca, Sr and Ba and/or
- Sb2O3
- 0-1%
- being free of F and having a refractive index within a range from 1.88 to 1.90 and comprising WO3 in an amount of less than 0.5% in mass % on oxide basis.
Dependencies are inferred from the claim text.