Optical glass and optical elements

Abstract

To provide an optical glass having an appropriate liquidus temperature, which reduces cost and simultaneously lowers the glass transition temperature Tg, while ensuring that the refractive index nd, Abbe number vd, and light transmittance remain unchanged, by using niobium oxide (Nb2O5) instead of tantalum oxide (Ta2O5) as the glass component, and by lowering the glass transition temperature Tg. Also to provide an optical element containing said optical glass. [Solution] The present invention provides optical glass and the like that satisfy conditions such as having an SiO2 content of 0.00-15.00%, a B2O3 content of 0.00-30.00%, a ZnO content of 0.00-25.00%, a La2O3 content of 20.00-50.00%, a Ta2O5 content of 0.00-1.50%, a Li2O content of 0.50-10.00%, a Y2O3 content of 0.00-1.90%, a WO3 content of 0.00-10.00%, a ZrO2 content of 0.00-9.00%, and a Nb2O5 content of 0.00-14.50%.

Description

[Technical Field]

[0001] The present invention relates to an optical glass having an appropriate liquidus temperature, which reduces costs and simultaneously lowers the glass transition temperature Tg, while ensuring that the refractive index nd, Abbe number vd, and light transmittance remain unchanged, and to an optical element containing the optical glass. [Background technology]

[0002] In the composition of optical glass, tantalum oxide (Ta2O5) can significantly improve the refractive index and simultaneously reduce color dispersion, but its price is very high, leading to a substantial increase in glass costs. Therefore, there is a need for optical glass that can reduce the tantalum oxide content in the glass composition through compositional adjustment while guaranteeing that the refractive index, Abbe number, and light transmittance remain unchanged. Patent Document 1 discloses optical glass containing Nb2O5, but its Ta2O5 content is relatively high. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Chinese Patent Publication No. 101128400 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Through extensive research, the inventors have discovered that by replacing tantalum oxide (Ta2O5) with niobium oxide (Nb2O5), which has similar properties, costs can be reduced. Furthermore, by appropriately decreasing the Nb content, costs can be further reduced. Simultaneously, while maintaining the inherent GMO (Glass Molding Optics) moldability, the glass transition temperature (Tg) can be lowered. This results in better thermal performance and improved market competitiveness of the glass material. Therefore, the object of the present invention is to provide an optical glass having an appropriate liquidus temperature, which reduces costs and simultaneously lowers the glass transition temperature Tg, while ensuring that the refractive index nd, Abbe number vd, and light transmittance remain unchanged, and an optical element containing the optical glass, by using niobium oxide (Nb2O5) instead of tantalum oxide (Ta2O5) as the glass component. [Means for solving the problem]

[0005] The gist of this invention is, for example, as follows: (1) In the glass composition of optical glass, when the total mass of the optical glass is assumed to be 100% by mass, The SiO2 content is 0.00 to 15.00% by mass. The B2O3 content is 0.00 to 30.00% by mass. The ZnO content is 0.00 to 25.00% by mass. The La2O3 content is 20.00 to 50.00% by mass. The Ta2O5 content is 0.00 to 1.50% by mass. The Li2O content is 0.50 to 10.00% by mass. The Y2O3 content is 0.00 to 1.90% by mass. The WO3 content is 0.00 to 10.00% by mass. The ZrO2 content is 0.00 to 9.00% by mass. The Nb2O5 content is 0.00 to 14.50% by mass. The mass ratio of the total content of Nb2O5, WO3, ZrO2, and La2O3 to the total content of ZnO, Li2O, B2O3, and SiO2 (Nb2O5+WO3+ZrO2+La2O3) / (ZnO+Li2O+B2O3+SiO2) is between 1.000 and 1.250. Optical glass in which the mass ratio (Nb2O5+WO3+Ta2O5) / (La2O3+Gd2O3+Y2O3) of the total content of Nb2O5, WO3, and Ta2O5 to the total content of La2O3, Gd2O3, and Y2O3 is 0.250 to 0.400.

[0006] (2) The optical glass described in (1), which satisfies at least one of the following conditions. The TiO2 content is 0.00 to 3.30% by mass. The Sb2O3 content is 0.00 to 5.00% by mass. The Gd2O3 content is between 0.00 and 10.00% by mass.

[0007] (3) The optical glass described in (1) or (2), which satisfies at least one of the following conditions. The mass ratio of the SiO2 content to the total SiO2 and B2O3 content, SiO2 / (SiO2+B2O3), is between 0.120 and 0.300. The mass ratio of the total content of Li2O, Na2O, and K2O to the total content of SiO2 and B2O3 (Li2O+Na2O+K2O) / (SiO2+B2O3) is between 0.010 and 0.150. The mass ratio of the total content of CaO, MgO, BaO, and SrO to the content of ZnO is (CaO+MgO+BaO+SrO) / ZnO, which is between 0.000 and 0.300. The mass ratio of the total content of La2O3, Gd2O3, and Y2O3 to the total content of SiO2 and B2O3 (La2O3+Gd2O3+Y2O3) / (SiO2+B2O3) is between 1.000 and 1.750. The mass ratio of Y2O3 content to the total content of La2O3, Gd2O3, and Y2O3, Y2O3 / (La2O3+Gd2O3+Y2O3), is between 0.000 and 0.050. The mass ratio of the total content of La2O3, Y2O3, and ZrO2 to the total content of SiO2, B2O3, and WO3 (La2O3+Y2O3+ZrO2) / (SiO2+B2O3+WO3) is between 1.000 and 1.750. The mass ratio of the total content of Nb2O5 and Ta2O5 to the total content of WO3 and TiO2 (Nb2O5+Ta2O5) / (WO3+TiO2) is between 1.060 and 1.350. a mass ratio of the total content of La₂O₃, Gd₂O₃ and Y₂O₃ to the total content of ZnO and ZrO₂, (La₂O₃+Gd₂O₃+Y₂O₃) / (ZnO+ZrO₂), of 1.200 to 1.850, a mass ratio of the content of B₂O₃ to the total content of ZnO and Li₂O, B₂O₃ / (ZnO+Li₂O), of 0.800 to 1.200, a mass ratio of the content of La₂O₃ to the total content of ZnO and Y₂O₃, La₂O₃ / (ZnO+Y₂O₃), of 1.500 to 2.200.

[0008] (4) The optical glass according to any one of (1) to (3), which satisfies at least one of the following: a mass ratio of the content of Li₂O to the total content of Li₂O, Na₂O and K₂O, Li₂O / (Li₂O+Na₂O+K₂O), of 0.500 to 1.000, a mass ratio of the total content of Nb₂O₅, WO₃ and TiO₂ to the total content of SiO₂ and B₂O₃, (Nb₂O₅+WO₃+TiO₂) / (SiO₂+B₂O₃), of 0.200 to 0.700, a mass ratio of the total content of Nb₂O₅ and WO₃ to the content of SiO₂, (Nb₂O₅+WO₃) / SiO₂, of 1.000 to 4.500, a mass ratio of the total content of Nb₂O₅, WO₃ and TiO₂ to the content of La₂O₃, (Nb₂O₅+WO₃+TiO₂) / La₂O₃, of 0.250 to 0.500, a mass ratio of the content of WO₃ to the total content of Nb₂O₅, WO₃ and TiO₂, WO₃ / (Nb₂O₅+WO₃+TiO₂), of 0.000 to 0.700, a mass ratio of the content of Ta₂O₅ to the total content of Nb₂O₅, WO₃ and Ta₂O₅, Ta₂O₅ / (Nb₂O₅+WO₃+Ta₂O₅), of 0.000 to 0.140, a mass ratio of the total content of Nb₂O₅, WO₃ and Ta₂O₅ to the total content of SiO₂, B₂O₃ and La₂O₃, (Nb₂O₅+WO₃+Ta₂O₅) / (SiO₂+B₂O₃+La₂O₃), of 0.050 to 0.285, a mass ratio of a total content of ZnO and Li₂O to a total content of SiO₂ and ZrO₂ (ZnO+Li₂O) / (SiO₂+ZrO₂) is 1.000 to 4.500, a mass ratio of a content of Li₂O to a total content of ZnO and Li₂O Li₂O / (ZnO+Li₂O) is 0.030 to 0.190, a mass ratio of a content of La₂O₃ to a total content of ZnO and ZrO₂ La₂O₃ / (ZnO+ZrO₂) is 1.200 to 1.850, a mass ratio of a content of B₂O₃ to a content of La₂O₃ B₂O₃ / La₂O₃ is 0.450 to 0.650, a mass ratio of a content of Y₂O₃ to a total content of Li₂O and ZnO Y₂O₃ / (Li₂O+ZnO) is 0.000 to 0.050.

[0009] (5) The optical glass according to any one of (1) to (4), which satisfies at least one of the following. a refractive index nd is 1.7500 to 1.8300, an Abbe number vd is 37 to 45, λ 80 is 380 to 430 nm, λ5 is 320 to 360 nm, a glass transition temperature Tg is 520 to 565°C, a specific gravity is 4.25 to 4.60, a liquidus temperature is 950 to 1080°C.

[0010] (6) The optical glass according to any one of (1) to (5), which satisfies at least one of the following. a SiO₂ content is 1.00 to 13.00 mass%, a B₂O₃ content is 5.00 to 29.00 mass%, a ZnO content is 5.00 to 24.50 mass%, a La₂O₃ content is 22.00 to 48.00 mass%, a Ta₂O₅ content is 0.00 to 1.20 mass%, a Li₂O content is 0.60 to 9.00 mass%, The Y2O3 content is 0.00 to 1.70% by mass. The WO3 content is 1.00 to 9.00% by mass. The ZrO2 content is 0.50 to 8.00% by mass. The Nb2O5 content is 1.00 to 13.50% by mass. The TiO2 content is 0.00 to 3.00 mass%, The Sb2O3 content is 0.01 to 4.00% by mass. The Gd2O3 content is 0.00 to 9.00% by mass. The mass ratio of the total content of Nb2O5, WO3, ZrO2, and La2O3 to the total content of ZnO, Li2O, B2O3, and SiO2 (Nb2O5+WO3+ZrO2+La2O3) / (ZnO+Li2O+B2O3+SiO2) is between 1.010 and 1.240. The mass ratio of the total content of Nb2O5, WO3, and Ta2O5 to the total content of La2O3, Gd2O3, and Y2O3 (Nb2O5+WO3+Ta2O5) / (La2O3+Gd2O3+Y2O3) is between 0.260 and 0.390. The mass ratio of the SiO2 content to the total SiO2 and B2O3 content, SiO2 / (SiO2+B2O3), is between 0.130 and 0.270. The mass ratio of the total content of Li2O, Na2O, and K2O to the total content of SiO2 and B2O3 (Li2O+Na2O+K2O) / (SiO2+B2O3) is between 0.020 and 0.130. The mass ratio of the total content of CaO, MgO, BaO, and SrO to the content of ZnO is (CaO+MgO+BaO+SrO) / ZnO, which is between 0.000 and 0.250. The mass ratio of the total content of La2O3, Gd2O3, and Y2O3 to the total content of SiO2 and B2O3 (La2O3+Gd2O3+Y2O3) / (SiO2+B2O3) is between 1.100 and 1.700. The mass ratio of Y2O3 content to the total content of La2O3, Gd2O3, and Y2O3, Y2O3 / (La2O3+Gd2O3+Y2O3), is between 0.000 and 0.040. The mass ratio of the total content of La2O3, Y2O3, and ZrO2 to the total content of SiO2, B2O3, and WO3 (La2O3+Y2O3+ZrO2) / (SiO2+B2O3+WO3) is between 1.050 and 1.700. The mass ratio of the total content of Nb2O5 and Ta2O5 to the total content of WO3 and TiO2 (Nb2O5+Ta2O5) / (WO3+TiO2) is between 1.070 and 1.250. The mass ratio of the total content of La2O3, Gd2O3, and Y2O3 to the total content of ZnO and ZrO2 (La2O3+Gd2O3+Y2O3) / (ZnO+ZrO2) is between 1.250 and 1.800. The mass ratio of B2O3 content to the total content of ZnO and Li2O, B2O3 / (ZnO+Li2O), is between 0.850 and 1.150. The mass ratio of La2O3 content to the total content of ZnO and Y2O3, La2O3 / (ZnO+Y2O3), is between 1.550 and 2.150. The mass ratio of the Li2O content to the total content of Li2O, Na2O, and K2O, Li2O / (Li2O+Na2O+K2O), is between 0.600 and 1.000. The mass ratio of the total content of Nb2O5, WO3, and TiO2 to the total content of SiO2 and B2O3 (Nb2O5+WO3+TiO2) / (SiO2+B2O3) is between 0.300 and 0.650. The mass ratio of the total content of Nb2O5 and WO3 to the SiO2 content (Nb2O5+WO3) / SiO2 is between 1.500 and 4.000. The mass ratio of the total content of Nb2O5, WO3, and TiO2 to the La2O3 content (Nb2O5+WO3+TiO2) / La2O3 is 0.270 to 0.480. The mass ratio of WO3 content to the total content of Nb2O5, WO3, and TiO2, WO3 / (Nb2O5+WO3+TiO2), is between 0.100 and 0.650. The mass ratio of Ta2O5 content to the total content of Nb2O5, WO3, and Ta2O5, Ta2O5 / (Nb2O5+WO3+Ta2O5), is between 0.000 and 0.120. The mass ratio of the total content of Nb2O5, WO3, and Ta2O5 to the total content of SiO2, B2O3, and La2O3 (Nb2O5+WO3+Ta2O5) / (SiO2+B2O3+La2O3) is between 0.070 and 0.280. The mass ratio of the total content of ZnO and Li2O to the total content of SiO2 and ZrO2 (ZnO + Li2O) / (SiO2 + ZrO2) is between 1.200 and 4.000. The mass ratio of Li2O content to the total content of ZnO and Li2O, Li2O / (ZnO+Li2O), is 0.040 to 0.150. The mass ratio of La2O3 content to the total content of ZnO and ZrO2, La2O3 / (ZnO+ZrO2), is between 1.300 and 1.750. The mass ratio of B2O3 content to La2O3 content, B2O3 / La2O3, is 0.470 to 0.630. The mass ratio of Y2O3 content to the total content of Li2O and ZnO, Y2O3 / (Li2O+ZnO), is between 0.000 and 0.040. The refractive index nd is 1.7700 to 1.8250. The Abbe number vd is between 37.5 and 44.5. λ 80 The range is 385-428nm, λ5 is 322-358 nm, The glass transition temperature Tg is 522~562°C. The specific gravity is 4.27 to 4.57. The liquidus temperature is 960-1060°C.

[0011] (7) An optical glass described in any one of items (1) to (6), which satisfies at least one of the following conditions: The SiO2 content is 2.00 to 11.00% by mass. The B2O3 content is 10.00 to 25.00% by mass. The ZnO content is 10.00 to 22.00% by mass. The La2O3 content is 30.00 to 40.00% by mass. The Ta2O5 content is 0.00 to 1.00% by mass. The Li2O content is 0.90 to 6.00% by mass. The Y2O3 content is 0.00 to 1.00% by mass. The WO3 content is 2.00 to 8.00% by mass. The ZrO2 content is 1.00 to 6.00% by mass. The Nb2O5 content is 4.00 to 10.50% by mass. The TiO2 content is 0.00 to 2.00 mass%, The Sb2O3 content is 0.02 to 3.00% by mass. The Gd2O3 content is 0.00 to 6.00% by mass. The mass ratio of the total content of Nb2O5, WO3, ZrO2, and La2O3 to the total content of ZnO, Li2O, B2O3, and SiO2 (Nb2O5+WO3+ZrO2+La2O3) / (ZnO+Li2O+B2O3+SiO2) is between 1.040 and 1.230. The mass ratio of the total content of Nb2O5, WO3, and Ta2O5 to the total content of La2O3, Gd2O3, and Y2O3 (Nb2O5+WO3+Ta2O5) / (La2O3+Gd2O3+Y2O3) is between 0.290 and 0.380. The mass ratio of the SiO2 content to the total SiO2 and B2O3 content, SiO2 / (SiO2+B2O3), is between 0.160 and 0.240. The mass ratio of the total content of Li2O, Na2O, and K2O to the total content of SiO2 and B2O3 (Li2O+Na2O+K2O) / (SiO2+B2O3) is between 0.030 and 0.110. The mass ratio of the total content of CaO, MgO, BaO, and SrO to the content of ZnO is (CaO+MgO+BaO+SrO) / ZnO, which is between 0.000 and 0.150. The mass ratio of the total content of La2O3, Gd2O3, and Y2O3 to the total content of SiO2 and B2O3 (La2O3+Gd2O3+Y2O3) / (SiO2+B2O3) is between 1.200 and 1.600. The mass ratio of Y2O3 content to the total content of La2O3, Gd2O3, and Y2O3, Y2O3 / (La2O3+Gd2O3+Y2O3), is between 0.000 and 0.030. The mass ratio of the total content of La2O3, Y2O3, and ZrO2 to the total content of SiO2, B2O3, and WO3 (La2O3+Y2O3+ZrO2) / (SiO2+B2O3+WO3) is between 1.100 and 1.500. The mass ratio of the total content of Nb2O5 and Ta2O5 to the total content of WO3 and TiO2 (Nb2O5+Ta2O5) / (WO3+TiO2) is between 1.080 and 1.200. The mass ratio of the total content of La2O3, Gd2O3, and Y2O3 to the total content of ZnO and ZrO2 (La2O3+Gd2O3+Y2O3) / (ZnO+ZrO2) is between 1.300 and 1.700. The mass ratio of B2O3 content to the total content of ZnO and Li2O, B2O3 / (ZnO+Li2O), is between 0.900 and 1.100. The mass ratio of La2O3 content to the total content of ZnO and Y2O3, La2O3 / (ZnO+Y2O3), is between 1.600 and 2.100. The mass ratio of the Li2O content to the total content of Li2O, Na2O, and K2O, Li2O / (Li2O+Na2O+K2O), is between 0.700 and 1.000. The mass ratio of the total content of Nb2O5, WO3, and TiO2 to the total content of SiO2 and B2O3 (Nb2O5+WO3+TiO2) / (SiO2+B2O3) is 0.400 to 0.600. The mass ratio of the total content of Nb2O5 and WO3 to the SiO2 content (Nb2O5+WO3) / SiO2 is between 2.000 and 3.500. The mass ratio of the total content of Nb2O5, WO3, and TiO2 to the La2O3 content (Nb2O5+WO3+TiO2) / La2O3 is 0.290 to 0.460. The mass ratio of WO3 content to the total content of Nb2O5, WO3, and TiO2, WO3 / (Nb2O5+WO3+TiO2), is 0.200 to 0.600. The mass ratio of Ta2O5 content to the total content of Nb2O5, WO3, and Ta2O5, Ta2O5 / (Nb2O5+WO3+Ta2O5), is between 0.000 and 0.100. The mass ratio of the total content of Nb2O5, WO3, and Ta2O5 to the total content of SiO2, B2O3, and La2O3 (Nb2O5+WO3+Ta2O5) / (SiO2+B2O3+La2O3) is between 0.100 and 0.270. The mass ratio of the total content of ZnO and Li2O to the total content of SiO2 and ZrO2 (ZnO + Li2O) / (SiO2 + ZrO2) is between 1.400 and 3.500. The mass ratio of Li2O content to the total content of ZnO and Li2O, Li2O / (ZnO+Li2O), is between 0.050 and 0.110. The mass ratio of La2O3 content to the total content of ZnO and ZrO2, La2O3 / (ZnO+ZrO2), is between 1.350 and 1.700. The mass ratio of B2O3 content to La2O3 content (B2O3 / La2O3) is 0.490 to 0.610. The mass ratio of Y2O3 content to the total content of Li2O and ZnO, Y2O3 / (Li2O+ZnO), is between 0.000 and 0.030. The refractive index nd is 1.8000 to 1.8200. The Abbe number vd is between 38.0 and 44.0. λ 80 The wavelength is 390-425nm, λ5 is 325-355 nm, The glass transition temperature Tg is 525~560°C. The specific gravity is 4.30 to 4.55. The liquidus temperature is 970-1040°C.

[0012] (8) An optical glass described in any one of items (1) to (7), which satisfies at least one of the following conditions: The SiO2 content is 3.00 to 9.00% by mass. The B2O3 content is 15.00 to 23.00% by mass. The ZnO content is 15.00 to 21.00% by mass. The La2O3 content is 32.00 to 38.00% by mass. The Ta2O5 content is 0.00 to 0.80% by mass. The Li2O content is 1.10 to 4.00% by mass. The Y2O3 content is 0.00 to 0.80% by mass. The WO3 content is 3.00 to 7.00% by mass. The ZrO2 content is 2.00 to 5.00% by mass. The Nb2O5 content is 5.00 to 8.50% by mass. The TiO2 content is 0.00 to 1.00 mass%, The Sb2O3 content is 0.03 to 1.00% by mass. The Gd2O3 content is 0.00 to 4.00% by mass. The mass ratio of the total content of Nb2O5, WO3, ZrO2, and La2O3 to the total content of ZnO, Li2O, B2O3, and SiO2 (Nb2O5+WO3+ZrO2+La2O3) / (ZnO+Li2O+B2O3+SiO2) is between 1.060 and 1.220. The mass ratio of the total content of Nb2O5, WO3, and Ta2O5 to the total content of La2O3, Gd2O3, and Y2O3 (Nb2O5+WO3+Ta2O5) / (La2O3+Gd2O3+Y2O3) is between 0.310 and 0.375. The mass ratio of the SiO2 content to the total SiO2 and B2O3 content, SiO2 / (SiO2+B2O3), is between 0.170 and 0.230. The mass ratio of the total content of Li2O, Na2O, and K2O to the total content of SiO2 and B2O3 (Li2O+Na2O+K2O) / (SiO2+B2O3) is between 0.040 and 0.090. The mass ratio of the total content of CaO, MgO, BaO, and SrO to the content of ZnO (CaO+MgO+BaO+SrO) / ZnO is between 0.000 and 0.100. The mass ratio of the total content of La2O3, Gd2O3, and Y2O3 to the total content of SiO2 and B2O3 (La2O3+Gd2O3+Y2O3) / (SiO2+B2O3) is between 1.300 and 1.550. The mass ratio of Y2O3 content to the total content of La2O3, Gd2O3, and Y2O3, Y2O3 / (La2O3+Gd2O3+Y2O3), is between 0.000 and 0.020. The mass ratio of the total content of La2O3, Y2O3, and ZrO2 to the total content of SiO2, B2O3, and WO3 (La2O3+Y2O3+ZrO2) / (SiO2+B2O3+WO3) is between 1.150 and 1.450. The mass ratio of the total content of Nb2O5 and Ta2O5 to the total content of WO3 and TiO2 (Nb2O5+Ta2O5) / (WO3+TiO2) is between 1.085 and 1.190. The mass ratio of the total content of La2O3, Gd2O3, and Y2O3 to the total content of ZnO and ZrO2 (La2O3+Gd2O3+Y2O3) / (ZnO+ZrO2) is between 1.350 and 1.650. The mass ratio of B2O3 content to the total content of ZnO and Li2O, B2O3 / (ZnO+Li2O), is between 0.920 and 1.050. The mass ratio of La2O3 content to the total content of ZnO and Y2O3, La2O3 / (ZnO+Y2O3), is between 1.650 and 2.050. The mass ratio of the Li2O content to the total content of Li2O, Na2O, and K2O, Li2O / (Li2O+Na2O+K2O), is between 0.800 and 1.000. The mass ratio of the total content of Nb2O5, WO3, and TiO2 to the total content of SiO2 and B2O3 (Nb2O5+WO3+TiO2) / (SiO2+B2O3) is 0.500 to 0.550. The mass ratio of the total content of Nb2O5 and WO3 to the SiO2 content (Nb2O5+WO3) / SiO2 is 2.500 to 3.000. The mass ratio of the total content of Nb2O5, WO3, and TiO2 to the La2O3 content (Nb2O5+WO3+TiO2) / La2O3 is 0.310 to 0.440. The mass ratio of WO3 content to the total content of Nb2O5, WO3, and TiO2, WO3 / (Nb2O5+WO3+TiO2), is 0.300 to 0.550. The mass ratio of Ta2O5 content to the total content of Nb2O5, WO3, and Ta2O5, Ta2O5 / (Nb2O5+WO3+Ta2O5), is 0.000 to 0.070. The mass ratio of the total content of Nb2O5, WO3, and Ta2O5 to the total content of SiO2, B2O3, and La2O3 (Nb2O5+WO3+Ta2O5) / (SiO2+B2O3+La2O3) is between 0.130 and 0.250. The mass ratio of the total content of ZnO and Li2O to the total content of SiO2 and ZrO2 (ZnO + Li2O) / (SiO2 + ZrO2) is between 1.600 and 3.000. The mass ratio of Li2O content to the total content of ZnO and Li2O, Li2O / (ZnO+Li2O), is 0.060 to 0.090. The mass ratio of La2O3 content to the total content of ZnO and ZrO2, La2O3 / (ZnO+ZrO2), is between 1.400 and 1.650. The mass ratio of B2O3 content to La2O3 content (B2O3 / La2O3) is 0.510 to 0.590. The mass ratio of Y2O3 content to the total content of Li2O and ZnO, Y2O3 / (Li2O+ZnO), is between 0.000 and 0.020. The refractive index nd is 1.8020 to 1.8150. The Abbe number vd is between 38.5 and 42.0. λ 80 The wavelength is 395-420nm, λ5 is 330-350 nm, The glass transition temperature Tg is 530-557°C. The specific gravity is 4.35 to 4.52. The liquidus temperature is 980-1020°C.

[0013] (9) An optical glass described in any one of items (1) to (8) below, which satisfies at least one of the following conditions: The SiO2 content is 4.00 to 7.00% by mass. The B2O3 content is 17.00 to 22.00% by mass. The ZnO content is 17.00 to 20.00% by mass. The La2O3 content is 34.00 to 37.00% by mass. The Ta2O5 content is 0.00 to 0.50% by mass. The Li2O content is 1.30 to 2.00% by mass. The Y2O3 content is 0.00 to 0.50% by mass. The WO3 content is 4.00 to 6.50% by mass. The ZrO2 content is 3.00 to 4.50% by mass. The Nb2O5 content is 6.00 to 7.50% by mass. The TiO2 content is 0.00 to 0.50 mass%, The Sb2O3 content is 0.04-0.07% by mass. The Gd2O3 content is 0.00 to 2.00% by mass. The mass ratio of the total content of Nb2O5, WO3, ZrO2, and La2O3 to the total content of ZnO, Li2O, B2O3, and SiO2 (Nb2O5+WO3+ZrO2+La2O3) / (ZnO+Li2O+B2O3+SiO2) is between 1.080 and 1.210. The mass ratio of the total content of Nb2O5, WO3, and Ta2O5 to the total content of La2O3, Gd2O3, and Y2O3 (Nb2O5+WO3+Ta2O5) / (La2O3+Gd2O3+Y2O3) is between 0.330 and 0.370. The mass ratio of the SiO2 content to the total SiO2 and B2O3 content, SiO2 / (SiO2+B2O3), is between 0.180 and 0.220. The mass ratio of the total content of Li2O, Na2O, and K2O to the total content of SiO2 and B2O3 (Li2O+Na2O+K2O) / (SiO2+B2O3) is between 0.045 and 0.080. The mass ratio of the total content of CaO, MgO, BaO, and SrO to the content of ZnO (CaO+MgO+BaO+SrO) / ZnO is between 0.000 and 0.050. The mass ratio of the total content of La2O3, Gd2O3, and Y2O3 to the total content of SiO2 and B2O3 (La2O3+Gd2O3+Y2O3) / (SiO2+B2O3) is between 1.350 and 1.500. The mass ratio of Y2O3 content to the total content of La2O3, Gd2O3, and Y2O3, Y2O3 / (La2O3+Gd2O3+Y2O3), is between 0.000 and 0.010. The mass ratio of the total content of La2O3, Y2O3, and ZrO2 to the total content of SiO2, B2O3, and WO3 (La2O3+Y2O3+ZrO2) / (SiO2+B2O3+WO3) is between 1.200 and 1.400. The mass ratio of the total content of Nb2O5 and Ta2O5 to the total content of WO3 and TiO2 (Nb2O5+Ta2O5) / (WO3+TiO2) is between 1.090 and 1.180. The mass ratio of the total content of La2O3, Gd2O3, and Y2O3 to the total content of ZnO and ZrO2 (La2O3+Gd2O3+Y2O3) / (ZnO+ZrO2) is between 1.400 and 1.600. The mass ratio of B2O3 content to the total content of ZnO and Li2O, B2O3 / (ZnO+Li2O), is between 0.940 and 1.000. The mass ratio of La2O3 content to the total content of ZnO and Y2O3, La2O3 / (ZnO+Y2O3), is between 1.700 and 2.000. The mass ratio of the Li2O content to the total content of Li2O, Na2O, and K2O, Li2O / (Li2O+Na2O+K2O), is between 0.900 and 1.000. The mass ratio of the total content of Nb2O5, WO3, and TiO2 to the La2O3 content (Nb2O5+WO3+TiO2) / La2O3 is 0.330 to 0.420. The mass ratio of WO3 content to the total content of Nb2O5, WO3, and TiO2, WO3 / (Nb2O5+WO3+TiO2), is 0.400 to 0.500. The mass ratio of Ta2O5 content to the total content of Nb2O5, WO3, and Ta2O5, Ta2O5 / (Nb2O5+WO3+Ta2O5), is 0.000 to 0.050. The mass ratio of the total content of Nb2O5, WO3, and Ta2O5 to the total content of SiO2, B2O3, and La2O3 (Nb2O5+WO3+Ta2O5) / (SiO2+B2O3+La2O3) is between 0.150 and 0.230. The mass ratio of the total content of ZnO and Li2O to the total content of SiO2 and ZrO2 (ZnO + Li2O) / (SiO2 + ZrO2) is between 1.800 and 2.500. The mass ratio of Li2O content to the total content of ZnO and Li2O, Li2O / (ZnO+Li2O), is 0.065 to 0.070. The mass ratio of La2O3 content to the total content of ZnO and ZrO2, La2O3 / (ZnO+ZrO2), is 1.450 to 1.600. The mass ratio of B2O3 content to La2O3 content, B2O3 / La2O3, is 0.530 to 0.570. The mass ratio of Y2O3 content to the total content of Li2O and ZnO, Y2O3 / (Li2O+ZnO), is between 0.000 and 0.010. The refractive index nd is 1.8030 to 1.8100. The Abbe number vd is between 39.0 and 41.5. λ 80 The wavelength is 400-415nm, λ5 is 335-345 nm, The glass transition temperature Tg is 535-555°C. The specific gravity is 4.40 to 4.50. The liquidus temperature is 990-1010°C.

[0014] (10) An optical element comprising optical glass as described in any one of items (1) to (9). [Effects of the Invention]

[0015] According to the present invention, Nb can be used instead of Ta as the glass component, and while ensuring that the refractive index nd, Abbe number vd, and light transmittance remain unchanged, it is possible to provide an optical glass having an appropriate liquidus temperature that simultaneously reduces the glass transition temperature Tg and lowers the cost, as well as an optical element containing said optical glass. [Modes for carrying out the invention]

[0016] Embodiments of the present invention will be described below. In the present invention and this specification, unless otherwise specified, the glass composition of optical glass is expressed on an oxide basis. Here, "glass composition on an oxide basis" means the glass composition obtained by converting it according to the substances that exist in the optical glass in the form of oxides after the glass raw materials have completely decomposed during melting, and each glass component is written as SiO2, TiO2, etc., according to convention. Unless otherwise specified, the content and total content of glass components are on a mass basis, and "%" refers to "mass%". The content of glass components can be quantified by known methods, such as inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). In this specification and the present invention, a component content of 0% by mass means that the component is substantially absent, and that the presence of unavoidable impurities is permitted at unavoidable impurity levels (usually less than or equal to 1% by mass overall, more specifically less than or equal to 1% by mass or less or 0.5% by mass or less for Al2O3, less than or equal to 0.15% by mass or less for HfO2, and less than or equal to 10 ppm for Fe-containing compounds and Cr-containing compounds). In this specification, unless otherwise specified, the refractive index refers to the refractive index nd at the helium d-line (wavelength 587.56 nm). The glass composition of the optical glass of the present invention will be described in more detail below.

[0017] (Glass composition) In the optical glass of the present invention, the SiO2 content is 0.00 to 15.00% by mass. The lower limit of the SiO2 content is preferably 1.00% by mass, and more preferably 1.50% by mass, 2.00% by mass, 2.50% by mass, 3.00% by mass, 3.50% by mass, 4.00% by mass, and 4.50% by mass, in the following order. The upper limit of the SiO2 content is preferably 13.00% by mass, and more preferably 12.00% by mass, 11.00% by mass, 10.00% by mass, 9.00% by mass, 8.00% by mass, 7.00% by mass, 6.00% by mass, and 5.00% by mass, in the following order. As a skeleton of the glass, SiO2 forms a glass network and has the effect of improving the mechanical strength and weather resistance of the glass. In the optical glass composition of the present invention, increasing the SiO2 content lowers the liquidus temperature of the glass and increases the viscosity of the glass. However, as long as the content is not too high, the melting properties of the powder do not deteriorate, nor does the glass transition temperature Tg rise excessively.

[0018] In the optical glass of the present invention, the B2O3 content is 0.00 to 30.00% by mass. The lower limit of the B2O3 content is preferably 5.00% by mass, and more preferably 6.00% by mass, 7.00% by mass, 8.00% by mass, 9.00% by mass, 10.00% by mass, 11.00% by mass, 12.00% by mass, 13.00% by mass, 14.00% by mass, 15.00% by mass, 16.00% by mass, 17.00% by mass, 18.00% by mass, and 19.00% by mass, in the following order. The upper limit of the B2O3 content is preferably 29.00% by mass, and more preferably 28.00% by mass, 27.00% by mass, 26.00% by mass, 25.00% by mass, 24.00% by mass, 23.00% by mass, 22.00% by mass, and 21.00% by mass, in the following order. B2O3 is a glass network forming body and can improve the meltability of the glass and improve the transmittance of the optical glass. In the optical glass composition of the present invention, increasing the B2O3 content lowers the liquidus temperature of the glass and reduces the viscosity of the glass. If the B2O3 content is not too high, excessive volatilization during high-temperature melting of the glass will not occur, which is advantageous for controlling the refractive index and Abbe number during the manufacturing process.

[0019] In the optical glass of the present invention, the ZnO content is 0.00 to 25.00 mass%. The lower limit of the ZnO content is preferably 5.00 mass%, and more preferably 6.00 mass%, 7.00 mass%, 8.00 mass%, 9.00 mass%, 10.00 mass%, 11.00 mass%, 12.00 mass%, 13.00 mass%, 14.00 mass%, 15.00 mass%, 16.00 mass%, 17.00 mass%, 18.00 mass%, and 19.00 mass%. The upper limit of the ZnO content is preferably 24.50% by mass, and more preferably 24.00% by mass, 23.50% by mass, 23.00% by mass, 22.50% by mass, 22.00% by mass, 21.50% by mass, 21.00% by mass, 20.50% by mass, and 20.00% by mass, in the following order. ZnO is a component that can improve the chemical stability of the glass, effectively lower the glass transition temperature (Tg), and reduce the viscosity of the glass. If the ZnO content is not too high, the tendency for crystallization of the glass will not increase, nor will the liquidus temperature of the glass become too high.

[0020] In the optical glass of the present invention, the La2O3 content is 20.00 to 50.00 mass%. The lower limit of the La2O3 content is preferably 22.00 mass%, and more preferably 25.00 mass%, 27.00 mass%, 30.00 mass%, 32.00 mass%, 34.00 mass%, and 36.00 mass%, in the following order. The upper limit of the La2O3 content is preferably 48.00 mass%, and more preferably 45.00 mass%, 43.00 mass%, 40.00 mass%, 38.00 mass%, and 37.00 mass%, in the following order. La2O3 can improve the refractive index of the glass, reduce the color dispersion of the glass, and adjust the optical constants. If the La2O3 content is not too high, the tendency of the glass to crystallize will not become too strong, and the liquidus temperature of the glass will not become too high.

[0021] In the optical glass of the present invention, the Ta2O5 content is 0.00 to 1.50% by mass. The Ta2O5 content is preferably 1.20% by mass or less, more preferably 1.00% by mass or less, 0.80% by mass or less, 0.60% by mass or less, 0.50% by mass or less, 0.40% by mass or less, 0.30% by mass or less, 0.20% by mass or less, 0.10% by mass or less, and most preferably 0.00% by mass. In glass, Ta2O5 significantly improves the refractive index and simultaneously reduces color dispersion. However, it should be noted that Ta2O5 is very expensive, and its presence increases the cost of the glass. In the optical glass of the present invention, the Li2O content is 0.50 to 10.00 mass%. The lower limit of the Li2O content is preferably 0.60 mass%, and more preferably 0.70 mass%, 0.80 mass%, 0.90 mass%, 1.00 mass%, 1.10 mass%, 1.20 mass%, and 1.30 mass%, in the following order. The upper limit of the Li2O content is preferably 9.00 mass%, and more preferably 8.00 mass%, 7.00 mass%, 6.00 mass%, 5.00 mass%, 4.00 mass%, 3.00 mass%, and 2.00 mass%, in the following order. Li2O, as a type of strong flux, significantly lowers the glass transition temperature Tg when increased in appropriate amounts. As long as the Li2O content is not too high, the liquidus temperature of the glass will not become too high, nor will the bond-breaking action of Li2O increase the tendency for crystallization of the glass, thus not degrading the stability of the glass.

[0022] In the optical glass of the present invention, the Y2O3 content is 0.00 to 1.90% by mass. The upper limit of the Y2O3 content is preferably 1.70% by mass, and more preferably 1.50% by mass, 1.20% by mass, 1.00% by mass, 0.80% by mass, 0.50% by mass, 0.30% by mass, 0.10% by mass, and most preferably 0.00% by mass. As an optional component of the optical glass of the present invention, Y2O3 can improve the refractive index of the glass and reduce color dispersion. As long as the Y2O3 content is not too high, the glass will not devitrify, and the liquidus temperature will not become too high. In the optical glass of the present invention, the WO3 content is 0.00 to 10.00% by mass. The WO3 content is preferably 1.00% by mass or more, and more preferably 2.00% by mass or more, 3.00% by mass or more, 4.00% by mass or more, 5.00% by mass or more, and 6.00% by mass or more, in the following order. The WO3 content is preferably 9.00% by mass or less, and more preferably 8.00% by mass or less, 7.00% by mass or less, and 6.50% by mass or less, in the following order. WO3 can improve the refractive index of the glass and reduce color dispersion, and at the same time, by increasing the amount of WO3 appropriately, the liquidus temperature can be appropriately lowered. As long as the WO3 content is not too high, it will not reduce the transmittance of the glass.

[0023] In the optical glass of the present invention, the ZrO2 content is 0.00 to 9.00 mass%. The lower limit of the ZrO2 content is preferably 0.50 mass%, and more preferably 1.00 mass%, 1.50 mass%, 2.00 mass%, 2.50 mass%, 3.00 mass%, 3.50 mass%, and 4.00 mass%, in the following order. The upper limit of the ZrO2 content is preferably 8.00 mass%, and more preferably 7.00 mass%, 6.00 mass%, 5.00 mass%, and 4.50 mass%, in the following order. ZrO2 is an intermediate oxide that can improve the refractive index and simultaneously reduce color dispersion, thereby adjusting the optical constants. As long as the ZrO2 content is not too high, the melting properties of the powder can be maintained, the viscosity of the glass will not increase, the tendency for crystallization can be appropriately suppressed, and the liquidus temperature of the glass will not become too high.

[0024] In the optical glass of the present invention, the Nb2O5 content is 0.00 to 14.50 mass%. The lower limit of the Nb2O5 content is preferably 1.00 mass%, and more preferably 2.00 mass%, 3.00 mass%, 4.00 mass%, 5.00 mass%, and 6.00 mass%, in the following order. The upper limit of the Nb2O5 content is preferably 13.50 mass%, and more preferably 12.50 mass%, 11.50 mass%, 10.50 mass%, 9.50 mass%, 8.50 mass%, and 7.50 mass%, in the following order. Nb2O5 can improve the refractive index and simultaneously reduce chromatic dispersion, thereby adjusting the optical constants. It is important to note that increasing the Nb2O5 content increases the specific gravity of the glass, and since its price is relatively high, it also increases the cost of the glass. In the optical glass of the present invention, the TiO2 content is 0.00 to 3.30% by mass. The TiO2 content is preferably 3.00% by mass or less, more preferably 2.50% by mass or less, 2.00% by mass or less, 1.50% by mass or less, 1.00% by mass or less, 0.50% by mass or less, 0.20% by mass or less, and most preferably 0.00% by mass. As an optional component of the optical glass of the present invention, TiO2 can improve the refractive index of the glass. As long as the TiO2 content is not too high, it will not degrade the light transmittance of the glass, nor will it degrade the GMO moldability of the glass.

[0025] In the optical glass of the present invention, the Sb2O3 content is 0.00 to 5.00 mass%. The lower limit of the Sb2O3 content is preferably 0.01 mass%, and more preferably 0.02 mass%, 0.03 mass%, and 0.04 mass%, in the following order. The upper limit of the Sb2O3 content is preferably 4.00 mass%, and more preferably 3.00 mass%, 2.00 mass%, 1.00 mass%, 0.50 mass%, 0.10 mass%, 0.07 mass%, and 0.05 mass%, in the following order. In the optical glass composition of the present invention, Sb2O3 plays the role of a clarifying agent and promotes the escape of bubbles from the glass liquid at high temperatures. As long as the Sb2O3 content is not too high, the light transmittance of the glass will not deteriorate.

[0026] In the optical glass of the present invention, the Gd2O3 content is 0.00 to 10.00% by mass. The Gd2O3 content is preferably 9.00% by mass or less, more preferably 8.00% by mass or less, 7.00% by mass or less, 6.00% by mass or less, 5.00% by mass or less, 4.00% by mass or less, 3.00% by mass or less, 2.00% by mass or less, 1.00% by mass or less, and most preferably 0.00% by mass. As an optional component of the optical glass of the present invention, Gd2O3 is a component that improves the refractive index of the glass and improves its resistance to devitrification. As long as the Gd2O3 content is not too high, it will not increase the specific gravity of the glass or increase the cost of the glass. In the optical glass of the present invention, R2O(Na,K) is an optional component of the optical glass of the present invention, and Na and K can lower the melting temperature of the glass. If the amount of R2O added is not too large, the viscosity of the glass will not become too low, nor will the moldability be reduced. In the optical glass of the present invention, RO (Ca, Mg, Ba, Sr) is an optional component of the optical glass of the present invention, and Ca, Mg, Ba, and Sr can all improve the devitrification resistance of the glass. As long as the amount of RO added is not too high, the tendency of crystallization of the glass can be appropriately suppressed and the stability of the glass can be maintained.

[0027] In the optical glass of the present invention, the mass ratio of the SiO2 content to the total content of SiO2 and B2O3, SiO2 / (SiO2+B2O3), is 0.120 to 0.300. The lower limit of this mass ratio SiO2 / (SiO2+B2O3) is preferably 0.130, and more preferably 0.140, 0.150, 0.160, 0.170, and 0.180 in the following order. The upper limit of this mass ratio SiO2 / (SiO2+B2O3) is preferably 0.270, and more preferably 0.260, 0.250, 0.240, 0.230, 0.220, and 0.210 in the following order. Both SiO2 and B2O3 are the skeletal structure of glass. If the ratio of SiO2 to the total amount of SiO2 and B2O3 is 0.120 or higher, the viscosity of the glass will not become too low, which is advantageous for production and molding. If the ratio of SiO2 to the total amount of SiO2 and B2O3 is 0.300 or lower, the glass meltability can be appropriately maintained, and the desired Abbe number can be achieved.

[0028] In the optical glass of the present invention, the mass ratio of the total content of Li2O, Na2O, and K2O to the total content of SiO2 and B2O3, (Li2O+Na2O+K2O) / (SiO2+B2O3), is 0.010 to 0.150. The lower limit of this mass ratio (Li2O+Na2O+K2O) / (SiO2+B2O3) is preferably 0.020, more preferably 0.030, 0.040, 0.045, 0.050, and 0.055, and the upper limit of this mass ratio (Li2O+Na2O+K2O) / (SiO2+B2O3) is preferably 0.130, and more preferably 0.110, 0.090, 0.080, 0.070, and 0.060, in the following order. If the mass ratio (Li2O+Na2O+K2O) / (SiO2+B2O3) is 0.010 or higher, the glass transition temperature Tg will not become too high. If the mass ratio (Li2O+Na2O+K2O) / (SiO2+B2O3) is 0.150 or lower, the tendency for glass crystallization will not become too strong, and good stability will be obtained.

[0029] In the optical glass of the present invention, the mass ratio of the total content of CaO, MgO, BaO, and SrO to the content of ZnO (CaO+MgO+BaO+SrO) / ZnO is 0.000 to 0.300. The upper limit of the mass ratio (CaO+MgO+BaO+SrO) / ZnO is preferably 0.250, and more preferably 0.200, 0.150, 0.100, 0.050, and 0.000 in the following order. Compared with other RO oxides (Ca, Mg, Ba, Sr), Zn can significantly lower the glass transition temperature Tg. If the mass ratio (CaO+MgO+BaO+SrO) / ZnO is 0.300 or less, the glass transition temperature Tg will not become too high, and the glass transition temperature Tg can be lowered to a desired range. In the optical glass of the present invention, the mass ratio of the total content of La2O3, Gd2O3, and Y2O3 to the total content of SiO2 and B2O3, (La2O3+Gd2O3+Y2O3) / (SiO2+B2O3), is 1.000 to 1.750. The lower limit of this mass ratio (La2O3+Gd2O3+Y2O3) / (SiO2+B2O3) is preferably 1.100, and more preferably 1.150, 1.200, 1.250, 1.300, 1.350, and 1.400 in the following order. The upper limit of this mass ratio (La2O3+Gd2O3+Y2O3) / (SiO2+B2O3) is preferably 1.700, and more preferably 1.650, 1.600, 1.550, and 1.500 in the following order. If the mass ratio (La2O3+Gd2O3+Y2O3) / (SiO2+B2O3) is 1.000 or higher, the glass is more likely to obtain the desired refractive index and color dispersion properties. If the mass ratio (La2O3+Gd2O3+Y2O3) / (SiO2+B2O3) is 1.750 or lower, the glass will not crystallize, the liquidus temperature will not become high, which is advantageous for manufacturing and molding, and the specific gravity will be kept low, which is advantageous for reducing the weight of the glass.

[0030] In the optical glass of the present invention, the mass ratio of the Y2O3 content to the total content of La2O3, Gd2O3, and Y2O3, Y2O3 / (La2O3+Gd2O3+Y2O3), is 0.000 to 0.050. The upper limit of this mass ratio Y2O3 / (La2O3+Gd2O3+Y2O3) is preferably 0.040, and more preferably 0.030, 0.020, 0.010, and most preferably 0.000, in the following order. Assuming that the total amount of rare earth elements (La, Gd, Y) remains constant, Y has the greatest influence on the liquidus temperature, and if the value of this mass ratio Y2O3 / (La2O3+Gd2O3+Y2O3) is 0.050 or less, the liquidus temperature of the glass will not become too high, which is advantageous for manufacturing and molding.

[0031] In the optical glass of the present invention, the mass ratio of the total content of La2O3, Y2O3, and ZrO2 to the total content of SiO2, B2O3, and WO3, (La2O3+Y2O3+ZrO2) / (SiO2+B2O3+WO3), is 1.000 to 1.750. The lower limit of the mass ratio (La2O3+Y2O3+ZrO2) / (SiO2+B2O3+WO3) is preferably 1.050, and more preferably 1.100, 1.150, 1.200, and 1.250 in the following order. The upper limit of the mass ratio (La2O3+Y2O3+ZrO2) / (SiO2+B2O3+WO3) is preferably 1.700, and more preferably 1.650, 1.600, 1.550, 1.500, 1.450, 1.400, 1.350, and 1.300 in the following order. La, Y, and Zr significantly increase the liquidus temperature of the glass, while Si, B, and W can maintain or decrease the liquidus temperature of the glass. If the mass ratio (La2O3+Y2O3+ZrO2) / (SiO2+B2O3+WO3) is 1.000 or greater, the glass will have the desired refractive index and Abbe number. If the mass ratio (La2O3+Y2O3+ZrO2) / (SiO2+B2O3+WO3) is 1.750 or less, the glass will not crystallize, and the liquidus temperature will not become too high, which is advantageous for glass manufacturing.

[0032] In the optical glass of the present invention, the mass ratio of the total content of Nb2O5, WO3, ZrO2, and La2O3 to the total content of ZnO, Li2O, B2O3, and SiO2 (Nb2O5+WO3+ZrO2+La2O3) / (ZnO+Li2O+B2O3+SiO2) is 1.000 to 1.250. The lower limit of the mass ratio (Nb2O5+WO3+ZrO2+La2O3) / (ZnO+Li2O+B2O3+SiO2) is preferably 1.010, and more preferably 1.020, 1.030, 1.040, 1.050, 1.060, 1.070, 1.080, 1.090, and 1.100 in the following order. The upper limit of the mass ratio (Nb2O5+WO3+ZrO2+La2O3) / (ZnO+Li2O+B2O3+SiO2) is preferably 1.240, and more preferably 1.230, 1.220, 1.210, 1.200, and 1.190 in the following order. Nb, W, Zr, and La belong to the high refractive index components in glass, while Zn, Li, B, and Si belong to the medium-low refractive index components. If the mass ratio (Nb2O5+WO3+ZrO2+La2O3) / (ZnO+Li2O+B2O3+SiO2) is 1.000 or greater, the glass can achieve the desired refractive index and Abbe number. If the mass ratio (Nb2O5+WO3+ZrO2+La2O3) / (ZnO+Li2O+B2O3+SiO2) is 1.250 or less, the stability of the glass can be maintained, and crystallization within the glass does not occur, which is advantageous for manufacturing.

[0033] In the optical glass of the present invention, the mass ratio of the total content of Nb2O5, WO3, and Ta2O5 to the total content of La2O3, Gd2O3, and Y2O3, (Nb2O5+WO3+Ta2O5) / (La2O3+Gd2O3+Y2O3), is 0.250 to 0.400. The lower limit of the mass ratio (Nb2O5+WO3+Ta2O5) / (La2O3+Gd2O3+Y2O3) is preferably 0.260, and more preferably 0.270, 0.290, 0.310, 0.330, and 0.350 in the following order. The upper limit of the mass ratio (Nb2O5+WO3+Ta2O5) / (La2O3+Gd2O3+Y2O3) is preferably 0.390, and more preferably 0.385, 0.380, 0.375, and 0.370 in the following order. If the mass ratio (Nb2O5+WO3+Ta2O5) / (La2O3+Gd2O3+Y2O3) is 0.250 or higher, the glass can obtain an appropriate Abbe number and the liquidus temperature will not become too high. If the mass ratio (Nb2O5+WO3+Ta2O5) / (La2O3+Gd2O3+Y2O3) is 0.400 or less, the cost will not increase.

[0034] In the optical glass of the present invention, the mass ratio (Nb2O5+Ta2O5) / (WO3+TiO2) of the total content of Nb2O5 and Ta2O5 to the total content of WO3 and TiO2 is 1.060 to 1.350. The lower limit of this mass ratio (Nb2O5+Ta2O5) / (WO3+TiO2) is preferably 1.070, and more preferably 1.080, 1.085, 1.090, 1.095, and 1.100 in the following order. The upper limit of this mass ratio (Nb2O5+Ta2O5) / (WO3+TiO2) is preferably 1.250, and more preferably 1.200, 1.190, 1.180, 1.170, 1.160, and 1.150 in the following order. If the mass ratio (Nb2O5+Ta2O5) / (WO3+TiO2) is 1.060 or higher, the GMO moldability of the glass will not deteriorate. If the mass ratio (Nb2O5+Ta2O5) / (WO3+TiO2) is 1.350 or lower, the cost of the glass will not increase.

[0035] In the optical glass of the present invention, the mass ratio of the total content of La2O3, Gd2O3, and Y2O3 to the total content of ZnO and ZrO2, (La2O3+Gd2O3+Y2O3) / (ZnO+ZrO2), is 1.200 to 1.850. The lower limit of this mass ratio (La2O3+Gd2O3+Y2O3) / (ZnO+ZrO2) is preferably 1.250, and more preferably 1.300, 1.350, 1.400, 1.450, and 1.500 in the following order. The upper limit of this mass ratio (La2O3+Gd2O3+Y2O3) / (ZnO+ZrO2) is preferably 1.800, and more preferably 1.750, 1.700, 1.650, 1.600, and 1.550 in the following order. If the mass ratio (La2O3+Gd2O3+Y2O3) / (ZnO+ZrO2) is 1.200 or higher, the glass can obtain the desired refractive index and will not crystallize inside the glass. If the mass ratio (La2O3+Gd2O3+Y2O3) / (ZnO+ZrO2) is 1.850 or lower, the glass can obtain the desired Abbe number.

[0036] In the optical glass of the present invention, the mass ratio of the B2O3 content to the total content of ZnO and Li2O, B2O3 / (ZnO+Li2O), is 0.800 to 1.200. The lower limit of this mass ratio B2O3 / (ZnO+Li2O) is preferably 0.850, and more preferably 0.900, 0.920, 0.940, and 0.950 in the following order. The upper limit of this mass ratio B2O3 / (ZnO+Li2O) is preferably 1.150, and more preferably 1.100, 1.050, and 1.000 in the following order. B is the most abundant skeletal element in the composition, and Zn and Li significantly lower the glass transition temperature Tg and raise the liquidus temperature of the glass in the composition. If the mass ratio B2O3 / (ZnO+Li2O) is 0.800 or higher, the manufactured glass will not crystallize, the liquidus temperature will not rise, and it will be advantageous for manufacturing and molding. If the mass ratio B2O3 / (ZnO+Li2O) is 1.2 or lower, the glass transition temperature Tg will not be reduced to the desired range.

[0037] In the optical glass of the present invention, the mass ratio of the La2O3 content to the total content of ZnO and Y2O3, La2O3 / (ZnO+Y2O3), is 1.500 to 2.200. The lower limit of this mass ratio La2O3 / (ZnO+Y2O3) is preferably 1.550, and more preferably 1.600, 1.650, 1.700, 1.750, 1.800, and 1.850 in the following order. The upper limit of this mass ratio La2O3 / (ZnO+Y2O3) is preferably 2.150, and more preferably 2.100, 2.050, 2.000, 1.950, and 1.900 in the following order. If the mass ratio La2O3 / (ZnO+Y2O3) is 2.200 or less, the liquidus temperature of the glass will not become too high, and the moldability of the glass will not decrease. If the mass ratio La2O3 / (ZnO+Y2O3) is 1.500 or higher, crystallization will not occur inside the manufactured glass, nor will the moldability of the glass be reduced.

[0038] In the optical glass of the present invention, the mass ratio of the Li2O content to the total content of Li2O, Na2O, and K2O, Li2O / (Li2O+Na2O+K2O), is 0.500 to 1.000. The lower limit of this mass ratio Li2O / (Li2O+Na2O+K2O) is preferably 0.600, and more preferably 0.700, 0.800, and 0.900 in the following order, and the mass ratio Li2O / (Li2O+Na2O+K2O) may be 1.000. Of Li2O, Na2O, and K2O, Li2O has the greatest influence on the glass transition temperature Tg, and by setting the mass ratio Li2O / (Li2O+Na2O+K2O) within the above range, it is easier to obtain the target glass transition temperature Tg.

[0039] In the optical glass of the present invention, the mass ratio of the total content of Nb2O5, WO3, and TiO2 to the total content of SiO2 and B2O3, (Nb2O5+WO3+TiO2) / (SiO2+B2O3), is 0.200 to 0.700. The lower limit of this mass ratio (Nb2O5+WO3+TiO2) / (SiO2+B2O3) is preferably 0.300, and more preferably 0.400 and 0.500 in the following order. The upper limit of this mass ratio (Nb2O5+WO3+TiO2) / (SiO2+B2O3) is preferably 0.650, and more preferably 0.600 and 0.550 in the following order. By setting the mass ratio (Nb2O5+WO3+TiO2) / (SiO2+B2O3) within the above range, it is possible to reduce costs, lower the glass transition temperature (Tg), and simultaneously control the difficulty of molding.

[0040] In the optical glass of the present invention, the mass ratio (Nb2O5+WO3) / SiO2 of the total content of Nb2O5 and WO3 to the SiO2 content is 1.000 to 4.500. The lower limit of the mass ratio (Nb2O5+WO3) / SiO2 is preferably 1.500, and more preferably 2.000 and 2.500 in the following order. The upper limit of the mass ratio (Nb2O5+WO3) / SiO2 is preferably 4.000, and more preferably 3.500 and 3.000 in the following order. By setting the mass ratio (Nb2O5+WO3) / SiO2 within the above range, costs can be reduced, the glass transition temperature (Tg) can be lowered, and the difficulty during molding can be controlled. In the optical glass of the present invention, the mass ratio (Nb2O5+WO3+TiO2) / La2O3 of the total content of Nb2O5, WO3, and TiO2 to the La2O3 content is 0.250 to 0.500. The lower limit of this mass ratio (Nb2O5+WO3+TiO2) / La2O3 is preferably 0.270, and more preferably 0.290, 0.310, 0.330, and 0.350 in the following order. The upper limit of this mass ratio (Nb2O5+WO3+TiO2) / La2O3 is preferably 0.480, and more preferably 0.460, 0.440, 0.420, and 0.400 in the following order. Setting the mass ratio (Nb2O5+WO3+TiO2) / La2O3 within the above range helps to obtain the target Abbe number.

[0041] In the optical glass of the present invention, the mass ratio of the WO3 content to the total content of Nb2O5, WO3, and TiO2, WO3 / (Nb2O5+WO3+TiO2), is 0.000 to 0.700. The lower limit of the mass ratio WO3 / (Nb2O5+WO3+TiO2) is preferably 0.100, and more preferably 0.200, 0.300, 0.400, and 0.450 in the following order. The upper limit of the mass ratio WO3 / (Nb2O5+WO3+TiO2) is preferably 0.650, and more preferably 0.600, 0.550, and 0.500 in the following order. By setting the mass ratio WO3 / (Nb2O5+WO3+TiO2) within the above range, the liquidus temperature of the glass and the difficulty during molding can be controlled. In the optical glass of the present invention, the mass ratio of Ta2O5 content to the total content of Nb2O5, WO3, and Ta2O5, Ta2O5 / (Nb2O5+WO3+Ta2O5), is 0.000 to 0.140. The upper limit of this mass ratio Ta2O5 / (Nb2O5+WO3+Ta2O5) is preferably 0.120, and more preferably 0.100, 0.070, 0.050, 0.030, and 0.010, in the following order. This mass ratio Ta2O5 / (Nb2O5+WO3+Ta2O5) may also be 0.000. By setting this mass ratio Ta2O5 / (Nb2O5+WO3+Ta2O5) within the above range, the cost of the glass can be controlled.

[0042] In the optical glass of the present invention, the mass ratio of the total content of Nb2O5, WO3, and Ta2O5 to the total content of SiO2, B2O3, and La2O3, (Nb2O5+WO3+Ta2O5) / (SiO2+B2O3+La2O3), is 0.050 to 0.285. The lower limit of the mass ratio (Nb2O5+WO3+Ta2O5) / (SiO2+B2O3+La2O3) is preferably 0.070, and more preferably 0.100, 0.130, 0.150, 0.170, 0.190, and 0.200 in the following order. The upper limit of the mass ratio (Nb2O5+WO3+Ta2O5) / (SiO2+B2O3+La2O3) is preferably 0.280, and more preferably 0.270, 0.260, 0.250, 0.240, 0.230, and 0.220 in the following order. By setting the mass ratio (Nb2O5+WO3+Ta2O5) / (SiO2+B2O3+La2O3) within the above range, the cost of the glass can be controlled.

[0043] In the optical glass of the present invention, the mass ratio (ZnO+Li2O) / (SiO2+ZrO2) of the total content of ZnO and Li2O to the total content of SiO2 and ZrO2 is 1.000 to 4.500. The lower limit of the mass ratio (ZnO+Li2O) / (SiO2+ZrO2) is preferably 1.200, and more preferably 1.400, 1.600, 1.800, 2.000, and 2.100 in the following order. The upper limit of the mass ratio (ZnO+Li2O) / (SiO2+ZrO2) is preferably 4.000, and more preferably 3.500, 3.000, 2.500, and 2.400 in the following order. By setting the mass ratio (ZnO+Li2O) / (SiO2+ZrO2) within the above range, the glass transition temperature Tg can be lowered.

[0044] In the optical glass of the present invention, the mass ratio of the Li2O content to the total content of ZnO and Li2O, Li2O / (ZnO+Li2O), is 0.030 to 0.190. The lower limit of the mass ratio Li2O / (ZnO+Li2O) is preferably 0.040, and more preferably 0.050, 0.060, and 0.065 in the following order. The upper limit of the mass ratio Li2O / (ZnO+Li2O) is preferably 0.150, and more preferably 0.110, 0.090, and 0.070 in the following order. By setting the mass ratio Li2O / (ZnO+Li2O) within the above range, the glass transition temperature Tg can be reduced to the maximum extent without changing the optical constants. In the optical glass of the present invention, the mass ratio of the La2O3 content to the total content of ZnO and ZrO2, La2O3 / (ZnO+ZrO2), is 1.200 to 1.850. The lower limit of this mass ratio La2O3 / (ZnO+ZrO2) is preferably 1.300, and more preferably 1.350, 1.400, 1.450, and 1.500 in the following order. The upper limit of this mass ratio La2O3 / (ZnO+ZrO2) is preferably 1.750, and more preferably 1.700, 1.650, 1.600, and 1.550 in the following order. Setting the mass ratio La2O3 / (ZnO+ZrO2) within the above range helps to obtain the target Abbe number.

[0045] In the optical glass of the present invention, the mass ratio of B2O3 content to La2O3 content, B2O3 / La2O3, is 0.450 to 0.650. The lower limit of the mass ratio B2O3 / La2O3 is preferably 0.470, and more preferably 0.490, 0.510, 0.530, and 0.550 in the following order. The upper limit of the mass ratio B2O3 / La2O3 is preferably 0.630, and more preferably 0.610, 0.590, and 0.570 in the following order. By setting the mass ratio B2O3 / La2O3 within the above range, the refractive index and Abbe number can be controlled within a desired range. In the optical glass of the present invention, the mass ratio of the Y2O3 content to the total content of Li2O and ZnO, Y2O3 / (Li2O+ZnO), is 0.000 to 0.050. The upper limit of this mass ratio Y2O3 / (Li2O+ZnO) is preferably 0.040, and more preferably 0.030, 0.020, and 0.010, in the following order. This mass ratio Y2O3 / (Li2O+ZnO) may also be 0.000. If this mass ratio Y2O3 / (Li2O+ZnO) is 0.050 or less, the liquidus temperature of the glass will not become too high, which is advantageous for manufacturing.

[0046] (Glass properties) <refractive index nd> The refractive index nd of the optical glass of the present invention may be between 1.75 and 1.83. The lower limit of the refractive index nd is preferably 1.7700, and more preferably 1.8000, 1.8020, 1.8030, 1.8040, 1.8050, and 1.8060 in the following order. The upper limit of the refractive index nd is preferably 1.8250, and more preferably 1.8200, 1.8150, 1.8100, 1.8090, 1.8080, and 1.8070 in the following order. The refractive index nd can be set to a desired value by appropriately adjusting the content of each glass component. Alternatively, the refractive index nd can also be set to a desired value by appropriately adjusting the respective content ratios.

[0047] <Abbe number vd> The Abbe number vd is a value that indicates the properties related to chromatic dispersion, and is expressed as vd = (nd-1) / (nF-nC) using the refractive indices nd, nF, and nC for the d-line, F-line, and C-line, respectively. In the optical glass of the present invention, the Abbe number vd can be 37 to 45. The lower limit of the Abbe number vd is preferably 37.5, and more preferably 38, 38.5, 39, 39.5, 40, and 40.5 in the following order. The upper limit of the Abbe number vd is preferably 44.5, and more preferably 44, 43, 42, 41.5, and 41. By appropriately adjusting the content of each glass component, the Abbe number vd can be adjusted to a desired value. Alternatively, for example, the Abbe number vd can also be adjusted to a desired value by appropriately adjusting each of the aforementioned content ratios.

[0048] <Light Transmittance of Glass> The light transmittance of the optical glass of the present invention is evaluated by the degree of coloring λ 80 and λ5. For a glass test sample with a thickness of 10.0 mm ± 0.1 mm, the spectral transmittance in the wavelength range of 200 to 700 nm is measured, and the wavelength at which the external transmittance reaches 80% by mass is defined as λ 80 , and the wavelength at which the external transmittance reaches 5% by mass is defined as λ5. λ of the optical glass of the present invention 80 may range from 380 to 430 nm. The lower limit of λ 80 is preferably 385 nm, and more preferably 388 nm, 390 nm, 392 nm, 395 nm, 398 nm, and 400 nm in the following order. The lower limit of λ 80 is preferably 428 nm, and more preferably 425 nm, 420 nm, 415 nm, and 410 nm in the following order. λ5 of the optical glass of the present invention may range from 320 to 360 nm. The lower limit of λ5 is preferably 322 nm, and more preferably 325 nm, 328 nm, 330 nm, and 335 nm in the following order. The upper limit of λ5 is preferably 358 nm, and more preferably 355 nm, 350 nm, 348 nm, 345 nm, and 340 nm in the following order. Note that λ 80 and λ5 of the optical glass of the present invention can be adjusted to a desired range by adjusting the content of each glass component and each of the aforementioned content ratios.

[0049] <Glass Transition Temperature Tg> The glass transition temperature Tg of the optical glass of the present invention is preferably 520 to 565°C. The lower limit of the glass transition temperature Tg is preferably 522°C, and more preferably 525°C, 527°C, 530°C, 532°C, 535°C, 537°C, and 540°C, in the following order. The upper limit of the glass transition temperature Tg is preferably 562°C, and more preferably 560°C, 557°C, 555°C, 553°C, 552°C, 551°C, and 550°C, in the following order. The glass transition temperature Tg can be set to a desired value by adjusting the content of each glass component. Alternatively, the glass transition temperature Tg can also be set to a desired value by appropriately adjusting the respective content ratios.

[0050] <Specific gravity of glass> The specific gravity of the optical glass of the present invention may be between 4.25 and 4.60. The lower limit of the specific gravity of the optical glass of the present invention is preferably 4.27, and more preferably 4.30, 4.35, and 4.40 in the following order. The upper limit of the specific gravity is preferably 4.57, and more preferably 4.55, 4.52, and 4.50 in the following order. The specific gravity of the glass can be adjusted to a desired value by appropriately adjusting the content of each glass component. Alternatively, the specific gravity of the glass can be adjusted to a desired value by appropriately adjusting the respective content ratios.

[0051] <Liquidus temperature of glass> The liquidus temperature of the optical glass of the present invention may be 950 to 1080°C. The lower limit of the liquidus temperature of the optical glass of the present invention is preferably 960°C, and more preferably 970°C, 980°C, 990°C, and 995°C, in the following order. The upper limit of the liquidus temperature is preferably 1060°C, and more preferably 1040°C, 1020°C, 1010°C, and 1005°C, in the following order. By appropriately adjusting the content of each glass component, the liquidus temperature of the glass can be set to a desired value. Furthermore, for example, by appropriately adjusting the respective content ratios, the liquidus temperature of the glass can also be set to a desired value.

[0052] (Manufacturing of optical glass) The glass of the present invention can be produced by blending glass raw materials to achieve the predetermined composition described above, and then using the blended glass raw materials according to known glass manufacturing methods. For example, several types of compounds can be blended and thoroughly mixed to form a batch raw material, and the batch raw material can be placed in a quartz crucible or a platinum crucible and subjected to rough melting. The molten material obtained from rough melting can be rapidly cooled and crushed to form cullet. Furthermore, the cullet can be placed in a platinum crucible, heated, and remelted to form molten glass, and after further clarification and homogenization, the molten glass can be shaped and slowly cooled to obtain optical glass. Known methods can be used for shaping and slow cooling of the molten glass. Furthermore, as long as the desired glass components can be introduced into the glass to achieve the desired content, the compounds used in the batch raw material formulation are not particularly limited, and examples of such compounds include oxides, carbonates, nitrates, hydroxides, and fluorides.

[0053] (Manufacturing of optical elements, etc.) When manufacturing optical elements using the optical glass of the present invention, known methods may be used. For example, in the manufacture of the optical glass described above, molten glass is poured into a mold and formed into a plate to produce a glass material made of the optical glass of the present invention. The obtained glass material is cut, ground, and polished as appropriate to produce fragments of a size and shape suitable for press molding. The fragments are heated and softened, and press molded (reheat press) is performed by known methods to produce an optical element blank that approximates the shape of the optical element. The optical element blank is annealed, and then ground and polished by known methods to produce an optical element. Depending on the intended use, the optical functional surface of the fabricated optical element may be coated with an anti-reflective coating, a total reflection coating, or the like. According to one embodiment of the present invention, an optical element formed from the above-mentioned optical glass can be provided. Examples of types of optical elements include lenses such as spherical lenses and aspherical lenses, prisms, and diffraction gratings. Examples of lens shapes include various shapes such as biconvex lenses, plano-convex lenses, biconcave lenses, plano-concave lenses, convex meniscus lenses, and concave meniscus lenses. The optical element can be manufactured by a method that includes a process of processing a glass molded body formed from the above-mentioned optical glass. Examples of processing include cutting, machining, rough grinding, finish grinding, and polishing. When performing such processing, using the above-mentioned glass can reduce breakage and stably provide high-quality optical elements. [Examples]

[0054] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the embodiments shown in the examples. Glass samples with the glass compositions shown in Tables 1 to 10 were prepared in the following order, and each was evaluated.

[0055] [Manufacturing of optical glass] First, oxides, hydroxides, carbonates, and nitrates corresponding to the constituent components of glass were prepared as raw materials. These materials were weighed and blended so that the resulting optical glass composition matched the compositions shown in Tables 1 to 10, and the materials were thoroughly mixed. The resulting blended raw materials (batch raw materials) were placed in a platinum crucible and heated at 1300°C for 2 to 4 hours to form molten glass. The mixture was then stirred to homogenize it, and after clarification, the molten glass was cast into a mold preheated to an appropriate temperature. The cast glass was heat-treated at an arbitrary temperature between Tg and 100°C below the glass transition temperature Tg for 30 minutes, and then allowed to cool to room temperature (25°C) in a furnace to obtain a glass sample.

[0056] [Confirmation of glass component composition] The content of each glass component in the obtained glass samples was measured by inductively coupled plasma atomic emission spectrometry (ICP-AES), and it was confirmed that the compositions matched those shown in Tables 1 to 10.

[0057] [Evaluation of the physical properties of optical glass] The obtained glass samples were further subjected to annealing treatment at approximately 30 minutes to 2 hours near the glass transition temperature Tg, and then cooled in a furnace at a cooling rate of -30°C / hour to room temperature (25°C) to obtain annealed samples. The refractive index, Abbe number vd, specific gravity, glass transition temperature Tg, and λ of the obtained annealed samples were measured. 70 The values ​​of λ5 and λ5 were measured, and the results are shown in Tables 1 to 10, respectively. (i) Refractive index nd and Abbe number vd For the above annealing samples, the refractive index nd was measured at the 12 wavelengths shown in Table A, according to the Japanese Industrial Standard (JIS) JIS B 7071-1 Method for measuring the refractive index of optical glass - Part 1: Minimum deflection method. Next, the refractive indices of each radiation obtained by measurement were substituted into the shot dispersion formula specified in Appendix B of the Japanese Industrial Standard (JIS) JIS B 7071-1 Method for measuring the refractive index of optical glass - Part 1: Minimum deflection method, and the constants of the shot dispersion formula were determined by the least squares method. Subsequently, the Abbe number vd was calculated using the shot dispersion formula with the specified constants. (ii) Specific gravity The specific gravity was measured using the Archimedes method. (iii) Glass transition temperature Tg The glass transition temperature (Tg) was measured using a differential scanning calorimeter (DSC3300SA) manufactured by NETZSCH JAPAN at a heating rate of 10°C / min. (iv)λ 80 λ5 The above annealing sample was processed to have a thickness of 10 mm and parallel, optically polished planes, and the spectral transmittance was measured in the wavelength range of 280 nm to 700 nm. The intensity of light rays incident perpendicularly to one of the optically polished planes was defined as intensity A, and the intensity of light rays emitted from the other plane was defined as intensity B, and the spectral transmittance B / A was calculated. The wavelength at which the spectral transmittance was 80 mass% was defined as λ 80 The wavelength at which the spectral transmittance is 5% by mass was defined as λ5. Note that the spectral transmittance includes the reflection loss of light rays from the surface of the test sample.

[0058] (v) Liquidus temperature LT Glass test samples containing each type of glass shown in the table below (volume: 10 cm³) 3 The glass test sample was placed in a platinum crucible and held in a glass melting furnace set to 1300°C for 20 minutes. After the glass test sample had completely melted and reached a molten state, the platinum crucible was removed from the glass melting furnace, and the glass test sample was allowed to cool in the platinum crucible until its temperature fell below 500°C. Subsequently, the platinum crucible was placed in a glass melting furnace set to temperature T°C and held for 2 hours. After removing it from the furnace, the platinum crucible containing the glass test sample was immediately (within 8 seconds) placed on a refractory material (such as a brick) at room temperature to cool the glass test sample to room temperature. Room temperature here is in the range of -10 to 80°C. After that, the surface and interior of the glass test sample were visually observed to check for the presence or absence of crystals. The above experiment was repeated by changing the temperature T°C in a range of 10°C within the range of 960 to 1100°C, and the lowest temperature at which no crystals were observed on the surface or inside the glass test sample was defined as the liquidus temperature LT.

[0059] [Table 1]

[0060] [Table 2]

[0061] [Table 3]

[0062] [Table 4]

[0063] [Table 5]

[0064] [Table 6]

[0065] [Table 7]

[0066] [Table 8]

[0067] [Table 9]

[0068] [Table 10]

[0069] According to Tables 1 to 10 above, the present invention allows for the use of Nb instead of Ta as the glass component, and, while guaranteeing that the refractive index nd, Abbe number vd, and light transmittance remain unchanged, it is possible to realize an optical glass with an appropriate liquidus temperature that simultaneously reduces costs and lowers the glass transition temperature Tg.

[0070] Furthermore, all embodiments disclosed herein are illustrative and not restrictive. The scope of the present invention should be understood to be defined by the claims rather than the foregoing description and to encompass all variations equivalent to the claims in meaning and scope.

[0071] For example, by performing the compositional adjustments described in the specification on the glass composition exemplified above, an optical glass according to one embodiment of the present invention can be produced.

[0072] Furthermore, naturally, two or more items described as examples or preferred scopes in the specification can be arbitrarily combined.

Claims

1. In the glass composition of optical glass, when the total mass of the optical glass is taken as 100% by mass, SiO 2 The content is 0.00 to 15.00% by mass. B 2 O 3 The content is 0.00 to 30.00% by mass. The ZnO content is 0.00 to 25.00% by mass. La 2 O 3 The content is 20.00 to 50.00% by mass. Ta 2 O 5 The content is 0.00 to 1.50% by mass. Li 2 The O content is 0.50 to 10.00% by mass. Y 2 O 3 the content is 0.00 to 1.90% by mass, WO 3 The content is 0.00 to 10.00% by mass. ZrO 2 The content is 0.00 to 9.00% by mass. Nb 2 O 5 The content is 0.00 to 14.50% by mass. Nb 2 O 5 WO 3 , ZrO 2 and La 2 O 3 Total content of ZnO, Li 2 O, B 2 O 3 and SiO 2 Mass ratio of total content (Nb 2 O 5 +WO 3 +ZrO 2 +La 2 O 3 ) / (ZnO+Li 2 O+B 2 O 3 +SiO 2 ) is between 1,000 and 1,250, Nb 2 O 5 WO 3 and Ta 2 O 5 The total content of La 2 O 3 , Gd 2 O 3 and Y 2 O 3 Mass ratio of total content (Nb 2 O 5 +WO 3 +Ta 2 O 5 ) / (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 Optical glass with a coefficient of 0.250 to 0.

400.

2. The optical glass according to claim 1, which satisfies at least one of the following conditions. TiO 2 The content is 0.00 to 3.30%, Sb 2 O 3 The content is 0.00 to 5.00%, Gd 2 O 3 The content is between 0.00 and 10.00%.

3. The optical glass according to claim 1, which satisfies at least one of the following conditions. SiO 2 SiO content 2 and B 2 O 3 Mass ratio of SiO to total content 2 / (SiO 2 +B 2 O 3 ) is between 0.120 and 0.300, Li 2 O, Na 2 O and K 2 Total O content of SiO 2 and B 2 O 3 Mass ratio of total content (Li 2 O + Na 2 O+K 2 O) / (SiO 2 +B 2 O 3 ) is between 0.010 and 0.150, The mass ratio of the total content of CaO, MgO, BaO, and SrO to the content of ZnO (CaO + MgO + BaO + SrO) / ZnO is between 0.000 and 0.

300. La 2 O 3 , Gd 2 O 3 and Y 2 O 3 the mass ratio of the total content of 2 to the total content of SiO 2 and B 3 O (La 2 O 3 + Gd 2 O 3 + Y 2 O 3 ) / (SiO 2 + B 2 O 3 ) is 1.000 to 1.750, Y 2 O 3 La content 2 O 3 , Gd 2 O 3 and Y 2 O 3 Mass ratio Y of total content 2 O 3 / (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) is between 0.000 and 0.050, La 2 O 3 , Y 2 O 3 and ZrO 2 Total content of SiO 2 , B 2 O 3 and WO 3 Mass ratio of total content (La 2 O 3 +Y 2 O 3 +ZrO 2 ) / (SiO 2 +B 2 O 3 +WO 3 ) is between 1,000 and 1,750, Nb 2 O 5 and Ta 2 O 5 WO 3 and TiO 2 Mass ratio of total content (Nb 2 O 5 +Ta 2 O 5 ) / (WO 3 +TiO 2 ) is between 1.060 and 1.350, La 2 O 3 , Gd 2 O 3 and Y 2 O 3 The total content of ZnO and ZrO 2 Mass ratio of total content (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) / (ZnO+ZrO 2 ) is between 1.200 and 1.850, B 2 O 3 The content of ZnO and Li 2 Mass ratio B to total O content 2 O 3 / (ZnO+Li 2 O) is between 0.800 and 1.200, La 2 O 3 The content of ZnO and Y 2 O 3 Mass ratio La to total content 2 O 3 / (ZnO+Y 2 O 3 The value is between 1,500 and 2,200.

4. The optical glass according to claim 1, satisfying at least one of the following conditions: Li 2 Li content of O 2 O, Na 2 O and K 2 Li as the mass ratio of the total O content 2 O / (Li 2 O + Na 2 O+K 2 O) is between 0.500 and 1.000, Nb 2 O 5 WO 3 and TiO 2 Total content of SiO 2 and B 2 O 3 Mass ratio of total content (Nb 2 O 5 +WO 3 +TiO 2 ) / (SiO 2 +B 2 O 3 ) is between 0.200 and 0.700, Nb 2 O 5 and WO 3 Total content of SiO 2 Mass ratio of content (Nb 2 O 5 +WO 3 ) / SiO 2 The range is 1,000 to 4,500. Nb 2 O 5 WO 3 and TiO 2 The total content of La 2 O 3 Mass ratio of content (Nb 2 O 5 +WO 3 +TiO 2 ) / La 2 O 3 The range is 0.250 to 0.

500. WO 3 Nb content 2 O 5 WO 3 and TiO 2 WO 3 / (Nb 2 O 5 +WO 3 +TiO 2 ) is between 0.000 and 0.700, Ta 2 O 5 Nb content 2 O 5 WO 3 and Ta 2 O 5 Mass ratio Ta to total content 2 O 5 / (Nb 2 O 5 +WO 3 +Ta 2 O 5 ) is between 0.000 and 0.140, Nb 2 O 5 WO 3 and Ta 2 O 5 Total content of SiO 2 , B 2 O 3 and La 2 O 3 Mass ratio of total content (Nb 2 O 5 +WO 3 +Ta 2 O 5 ) / (SiO 2 +B 2 O 3 +La 2 O 3 ) is between 0.050 and 0.285, ZnO and Li 2 Total O content of SiO 2 and ZrO 2 Mass ratio of total content (ZnO + Li 2 O) / (SiO 2 +ZrO 2 ) is between 1,000 and 4,500. Li 2 O content of ZnO and Li 2 Li as the mass ratio of the total O content 2 O / (ZnO+Li 2 O) is between 0.030 and 0.190, La 2 O 3 The content of ZnO and ZrO 2 Mass ratio La to total content 2 O 3 / (ZnO+ZrO) 2 ) is between 1.200 and 1.850, B 2 O 3 La content 2 O 3 Mass ratio B of the content 2 O 3 / La 2 O 3 The range is 0.450 to 0.

650. Y 2 O 3 Li content 2 Mass ratio Y of the total content of O and ZnO 2 O 3 / (Li 2 The O + ZnO ratio is between 0.000 and 0.

050.

5. The optical glass according to claim 1, which satisfies at least one of the following conditions. The refractive index nd is 1.7500 to 1.8300. The Abbe number vd is between 37 and 45. λ 80 The wavelength is 380-430 nm. λ 5 The wavelength is 320-360 nm. The glass transition temperature Tg is 520 to 565°C. The specific gravity is 4.25 to 4.

60. The liquidus temperature is between 950 and 1080°C.

6. The optical glass according to claim 1, which satisfies at least one of the following conditions. SiO 2 The content is 1.00 to 13.00% by mass. B 2 O 3 The content is 5.00 to 29.00% by mass. The ZnO content is 5.00 to 24.50% by mass. La 2 O 3 The content is 22.00 to 48.00% by mass. Ta 2 O 5 The content is 0.00 to 1.20% by mass. Li 2 The O content is 0.60 to 9.00% by mass. Y 2 O 3 The content is 0.00 to 1.70% by mass. WO 3 The content is 1.00 to 9.00% by mass. ZrO 2 The content is 0.50 to 8.00% by mass, Nb 2 O 5 The content is 1.00 to 13.50% by mass. TiO 2 The content is 0.00 to 3.00% by mass. Sb 2 O 3 The content is 0.01 to 4.00% by mass, Gd 2 O 3 The content is 0.00 to 9.00% by mass. Nb 2 O 5 WO 3 , ZrO 2 and La 2 O 3 Total content of ZnO, Li 2 O, B 2 O 3 and SiO 2 Mass ratio of total content (Nb 2 O 5 +WO 3 +ZrO 2 +La 2 O 3 ) / (ZnO+Li 2 O+B 2 O 3 +SiO 2 ) is between 1.010 and 1.240, Nb 2 O 5 WO 3 and Ta 2 O 5 The total content of La 2 O 3 , Gd 2 O 3 and Y 2 O 3 Mass ratio of total content (Nb 2 O 5 +WO 3 +Ta 2 O 5 ) / (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) is between 0.260 and 0.390, SiO 2 SiO content 2 and B 2 O 3 Mass ratio of SiO to total content 2 / (SiO 2 +B 2 O 3 ) is between 0.130 and 0.270, Li 2 O, Na 2 O and K 2 Total O content of SiO 2 and B 2 O 3 Mass ratio of total content (Li 2 O + Na 2 O+K 2 O) / (SiO 2 +B 2 O 3 ) is between 0.020 and 0.130, The mass ratio of the total content of CaO, MgO, BaO, and SrO to the content of ZnO (CaO + MgO + BaO + SrO) / ZnO is between 0.000 and 0.

250. La 2 O 3 , Gd 2 O 3 and Y 2 O 3 Total content of SiO 2 and B 2 O 3 Mass ratio of total content (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) / (SiO 2 +B 2 O 3 ) is between 1.100 and 1.700, Y 2 O 3 La content 2 O 3 , Gd 2 O 3 and Y 2 O 3 Mass ratio Y of total content 2 O 3 / (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) is between 0.000 and 0.040, La 2 O 3 , Y 2 O 3 and ZrO 2 Total content of SiO 2 , B 2 O 3 and WO 3 Mass ratio of total content (La 2 O 3 +Y 2 O 3 +ZrO 2 ) / (SiO 2 +B 2 O 3 +WO 3 ) is between 1.050 and 1.700, Nb 2 O 5 and Ta 2 O 5 WO 3 and TiO 2 Mass ratio of total content (Nb 2 O 5 +Ta 2 O 5 ) / (WO 3 +TiO 2 ) is between 1.070 and 1.250, La 2 O 3 , Gd 2 O 3 and Y 2 O 3 The total content of ZnO and ZrO 2 Mass ratio of total content (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) / (ZnO+ZrO 2 ) is between 1.250 and 1.800, B 2 O 3 The content of ZnO and Li 2 Mass ratio B to total O content 2 O 3 / (ZnO+Li 2 O) is between 0.850 and 1.150, La 2 O 3 The content of ZnO and Y 2 O 3 Mass ratio La to total content 2 O 3 / (ZnO+Y 2 O 3 ) is between 1.550 and 2.150, Li 2 Li content of O 2 O, Na 2 O and K 2 Li as the mass ratio of the total O content 2 O / (Li 2 O + Na 2 O+K 2 O) is between 0.600 and 1.000, Nb 2 O 5 WO 3 and TiO 2 Total content of SiO 2 and B 2 O 3 Mass ratio of total content (Nb 2 O 5 +WO 3 +TiO 2 ) / (SiO 2 +B 2 O 3 ) is between 0.300 and 0.650, Nb 2 O 5 and WO 3 Total content of SiO 2 Mass ratio of content (Nb 2 O 5 +WO 3 ) / SiO 2 The range is 1,500 to 4,000. Nb 2 O 5 WO 3 and TiO 2 The total content of La 2 O 3 Mass ratio of content (Nb 2 O 5 +WO 3 +TiO 2 ) / La 2 O 3 The values ​​are 0.270 to 0.

480. WO 3 Nb content 2 O 5 WO 3 and TiO 2 WO 3 / (Nb 2 O 5 +WO 3 +TiO 2 ) is between 0.100 and 0.650, Ta 2 O 5 Nb content 2 O 5 WO 3 and Ta 2 O 5 Mass ratio Ta to total content 2 O 5 / (Nb 2 O 5 +WO 3 +Ta 2 O 5 ) is between 0.000 and 0.120, Nb 2 O 5 WO 3 and Ta 2 O 5 Total content of SiO 2 , B 2 O 3 and La 2 O 3 Mass ratio of total content (Nb 2 O 5 +WO 3 +Ta 2 O 5 ) / (SiO 2 +B 2 O 3 +La 2 O 3 ) is between 0.070 and 0.280, ZnO and Li 2 Total O content of SiO 2 and ZrO 2 Mass ratio of total content (ZnO + Li 2 O) / (SiO 2 +ZrO 2 ) is between 1,200 and 4,000. Li 2 O content of ZnO and Li 2 Li as the mass ratio of the total O content 2 O / (ZnO+Li 2 O) is between 0.040 and 0.150, La 2 O 3 The content of ZnO and ZrO 2 Mass ratio La to total content 2 O 3 / (ZnO+ZrO) 2 ) is between 1.300 and 1.750, B 2 O 3 La content 2 O 3 Mass ratio B of the content 2 O 3 / La 2 O 3 The values ​​are 0.470 to 0.

630. Y 2 O 3 Li content 2 Mass ratio Y of the total content of O and ZnO 2 O 3 / (Li 2 The O + ZnO ratio is between 0.000 and 0.

040. The refractive index nd is 1.7700 to 1.8250. The Abbe number vd is between 37.5 and 44.

5. λ 80 The range is 385-428 nm, λ 5 The wavelength is 322-358 nm. The glass transition temperature Tg is 522 to 562°C. The specific gravity is 4.27 to 4.

57. The liquidus temperature is between 960 and 1060°C.

7. The optical glass according to claim 1, which satisfies at least one of the following conditions. SiO 2 The content is 2.00 to 11.00% by mass. B 2 O 3 The content is 10.00 to 25.00% by mass. The ZnO content is 10.00 to 22.00% by mass. La 2 O 3 The content is 30.00 to 40.00% by mass. Ta 2 O 5 The content is 0.00 to 1.00% by mass, Li 2 The O content is 0.90 to 6.00% by mass. Y 2 O 3 The content is 0.00 to 1.00% by mass, WO 3 The content is 2.00 to 8.00% by mass. ZrO 2 The content is 1.00 to 6.00% by mass. Nb 2 O 5 The content is 4.00 to 10.50% by mass. TiO 2 The content is 0.00 to 2.00% by mass. Sb 2 O 3 The content is 0.02 to 3.00% by mass. Gd 2 O 3 The content is 0.00 to 6.00% by mass. Nb 2 O 5 WO 3 , ZrO 2 and La 2 O 3 Total content of ZnO, Li 2 O, B 2 O 3 and SiO 2 Mass ratio of total content (Nb 2 O 5 +WO 3 +ZrO 2 +La 2 O 3 ) / (ZnO+Li 2 O+B 2 O 3 +SiO 2 ) is between 1.040 and 1.230, Nb 2 O 5 WO 3 and Ta 2 O 5 The total content of La 2 O 3 , Gd 2 O 3 and Y 2 O 3 Mass ratio of total content (Nb 2 O 5 +WO 3 +Ta 2 O 5 ) / (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) is between 0.290 and 0.380, SiO 2 SiO content 2 and B 2 O 3 Mass ratio of SiO to total content 2 / (SiO 2 +B 2 O 3 ) is between 0.160 and 0.240, Li 2 O, Na 2 O and K 2 Total O content of SiO 2 and B 2 O 3 Mass ratio of total content (Li 2 O + Na 2 O+K 2 O) / (SiO 2 +B 2 O 3 ) is between 0.030 and 0.110, The mass ratio of the total content of CaO, MgO, BaO, and SrO to the content of ZnO (CaO + MgO + BaO + SrO) / ZnO is between 0.000 and 0.

150. La 2 O 3 , Gd 2 O 3 and Y 2 O 3 Total content of SiO 2 and B 2 O 3 Mass ratio of total content (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) / (SiO 2 +B 2 O 3 ) is between 1.200 and 1.600, Y 2 O 3 La content 2 O 3 , Gd 2 O 3 and Y 2 O 3 Mass ratio Y of total content 2 O 3 / (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) is between 0.000 and 0.030, La 2 O 3 , Y 2 O 3 and ZrO 2 Total content of SiO 2 , B 2 O 3 and WO 3 Mass ratio of total content (La 2 O 3 +Y 2 O 3 +ZrO 2 ) / (SiO 2 +B 2 O 3 +WO 3 ) is between 1.100 and 1.500, Nb 2 O 5 and Ta 2 O 5 WO 3 and TiO 2 Mass ratio of total content (Nb 2 O 5 +Ta 2 O 5 ) / (WO 3 +TiO 2 ) is between 1.080 and 1.200, La 2 O 3 , Gd 2 O 3 and Y 2 O 3 The total content of ZnO and ZrO 2 Mass ratio of total content (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) / (ZnO+ZrO 2 ) is between 1.300 and 1.700, B 2 O 3 The content of ZnO and Li 2 Mass ratio B to total O content 2 O 3 / (ZnO+Li 2 O) is between 0.900 and 1.100, La 2 O 3 The content of ZnO and Y 2 O 3 Mass ratio La to total content 2 O 3 / (ZnO+Y 2 O 3 ) is between 1,600 and 2,100. Li 2 Li content of O 2 O, Na 2 O and K 2 Li as the mass ratio of the total O content 2 O / (Li 2 O + Na 2 O+K 2 O) is between 0.700 and 1.000, Nb 2 O 5 WO 3 and TiO 2 Total content of SiO 2 and B 2 O 3 Mass ratio of total content (Nb 2 O 5 +WO 3 +TiO 2 ) / (SiO 2 +B 2 O 3 ) is between 0.400 and 0.

600. Nb 2 O 5 and WO 3 Total content of SiO 2 Mass ratio of content (Nb 2 O 5 +WO 3 ) / SiO 2 The range is 2,000 to 3,500. Nb 2 O 5 WO 3 and TiO 2 The total content of La 2 O 3 Mass ratio of content (Nb 2 O 5 +WO 3 +TiO 2 ) / La 2 O 3 The values ​​are 0.290 to 0.

460. WO 3 Nb content 2 O 5 WO 3 and TiO 2 WO 3 / (Nb 2 O 5 +WO 3 +TiO 2 ) is between 0.200 and 0.600, Ta 2 O 5 Nb content 2 O 5 WO 3 and Ta 2 O 5 Mass ratio Ta to total content 2 O 5 / (Nb 2 O 5 +WO 3 +Ta 2 O 5 ) is between 0.000 and 0.100, Nb 2 O 5 WO 3 and Ta 2 O 5 Total content of SiO 2 , B 2 O 3 and La 2 O 3 Mass ratio of total content (Nb 2 O 5 +WO 3 +Ta 2 O 5 ) / (SiO 2 +B 2 O 3 +La 2 O 3 ) is between 0.100 and 0.270, ZnO and Li 2 Total O content of SiO 2 and ZrO 2 Mass ratio of total content (ZnO + Li 2 O) / (SiO 2 +ZrO 2 ) is between 1,400 and 3,500. Li 2 O content of ZnO and Li 2 Li as the mass ratio of the total O content 2 O / (ZnO+Li 2 O) is between 0.050 and 0.110, La 2 O 3 The content of ZnO and ZrO 2 Mass ratio La to total content 2 O 3 / (ZnO+ZrO) 2 ) is between 1.350 and 1.700, B 2 O 3 La content 2 O 3 Mass ratio B of the content 2 O 3 / La 2 O 3 The values ​​are 0.490 to 0.

610. Y 2 O 3 Li content 2 Mass ratio Y of the total content of O and ZnO 2 O 3 / (Li 2 The O + ZnO ratio is between 0.000 and 0.

030. The refractive index nd is 1.8000 to 1.8200. The Abbe number vd is between 38.0 and 44.

0. λ 80 The wavelength is 390-425 nm. λ 5 The wavelength is 325-355 nm. The glass transition temperature Tg is 525 to 560°C. The specific gravity is 4.30 to 4.

55. The liquidus temperature is between 970 and 1040°C.

8. The optical glass according to claim 1, which satisfies at least one of the following conditions. SiO 2 The content is 3.00 to 9.00% by mass. B 2 O 3 The content is 15.00 to 23.00% by mass. The ZnO content is 15.00 to 21.00% by mass. La 2 O 3 The content is 32.00 to 38.00% by mass. Ta 2 O 5 The content is 0.00 to 0.80% by mass. Li 2 The O content is 1.10 to 4.00% by mass. Y 2 O 3 The content is 0.00 to 0.80% by mass. WO 3 The content is 3.00 to 7.00% by mass. ZrO 2 The content is 2.00 to 5.00% by mass. Nb 2 O 5 The content is 5.00 to 8.50% by mass. TiO 2 The content is 0.00 to 1.00% by mass, Sb 2 O 3 The content is 0.03 to 1.00% by mass, Gd 2 O 3 The content is 0.00 to 4.00% by mass. Nb 2 O 5 , WO 3 , ZrO 2 and La 2 O 3 , the mass ratio of the total content of ZnO, Li 2 O, B 2 O 3 and SiO 2 to the total content (Nb 2 O 5 +WO 3 +ZrO 2 +La 2 O 3 ) / (ZnO+Li 2 O+B 2 O 3 +SiO 2 ) is 1.060 to 1.220, Nb 2 O 5 WO 3 and Ta 2 O 5 The total content of La 2 O 3 , Gd 2 O 3 and Y 2 O 3 Mass ratio of total content (Nb 2 O 5 +WO 3 +Ta 2 O 5 ) / (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) is between 0.310 and 0.375, SiO 2 SiO content 2 and B 2 O 3 Mass ratio of SiO to total content 2 / (SiO 2 +B 2 O 3 ) is between 0.170 and 0.230, Li 2 O, Na 2 O and K 2 Total O content of SiO 2 and B 2 O 3 Mass ratio of total content (Li 2 O + Na 2 O+K 2 O) / (SiO 2 +B 2 O 3 ) is between 0.040 and 0.090, The mass ratio of the total content of CaO, MgO, BaO, and SrO to the content of ZnO (CaO + MgO + BaO + SrO) / ZnO is between 0.000 and 0.

100. La 2 O 3 , Gd 2 O 3 and Y 2 O 3 the mass ratio of the total content of to the total content of SiO 2 and B 2 O 3 (La 2 O 3 + Gd 2 O 3 + Y 2 O 3 ) / (SiO 2 + B 2 O 3 ) is 1.300 to 1.550, Y 2 O 3 La content 2 O 3 , Gd 2 O 3 and Y 2 O 3 Mass ratio Y of total content 2 O 3 / (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) is between 0.000 and 0.020, La 2 O 3 , Y 2 O 3 and ZrO 2 Total content of SiO 2 , B 2 O 3 and WO 3 Mass ratio of total content (La 2 O 3 +Y 2 O 3 +ZrO 2 ) / (SiO 2 +B 2 O 3 +WO 3 ) is between 1.150 and 1.450, Nb 2 O 5 and Ta 2 O 5 WO 3 and TiO 2 Mass ratio of total content (Nb 2 O 5 +Ta 2 O 5 ) / (WO 3 +TiO 2 ) is between 1.085 and 1.190, La 2 O 3 , Gd 2 O 3 and Y 2 O 3 The total content of ZnO and ZrO 2 Mass ratio of total content (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) / (ZnO+ZrO 2 ) is between 1.350 and 1.650, B 2 O 3 The content of ZnO and Li 2 Mass ratio B to total O content 2 O 3 / (ZnO+Li 2 O) is between 0.920 and 1.050, La 2 O 3 The content of ZnO and Y 2 O 3 Mass ratio La to total content 2 O 3 / (ZnO+Y 2 O 3 ) is between 1.650 and 2.

050. Li 2 Li content of O 2 O, Na 2 O and K 2 Li as the mass ratio of the total O content 2 O / (Li 2 O + Na 2 O+K 2 O) is between 0.800 and 1.000, Nb 2 O 5 WO 3 and TiO 2 Total content of SiO 2 and B 2 O 3 Mass ratio of total content (Nb 2 O 5 +WO 3 +TiO 2 ) / (SiO 2 +B 2 O 3 ) is between 0.500 and 0.550, Nb 2 O 5 and WO 3 Total content of SiO 2 Mass ratio of content (Nb 2 O 5 +WO 3 ) / SiO 2 The range is 2,500 to 3,000. Nb 2 O 5 WO 3 and TiO 2 The total content of La 2 O 3 Mass ratio of content (Nb 2 O 5 +WO 3 +TiO 2 ) / La 2 O 3 The values ​​are 0.310 to 0.

440. WO 3 Nb content 2 O 5 WO 3 and TiO 2 WO 3 / (Nb 2 O 5 +WO 3 +TiO 2 ) is between 0.300 and 0.550, Ta 2 O 5 Nb content 2 O 5 WO 3 and Ta 2 O 5 Mass ratio Ta to total content 2 O 5 / (Nb 2 O 5 +WO 3 +Ta 2 O 5 ) is between 0.000 and 0.070, Nb 2 O 5 WO 3 and Ta 2 O 5 Total content of SiO 2 , B 2 O 3 and La 2 O 3 Mass ratio of total content (Nb 2 O 5 +WO 3 +Ta 2 O 5 ) / (SiO 2 +B 2 O 3 +La 2 O 3 ) is between 0.130 and 0.250, ZnO and Li 2 Total O content of SiO 2 and ZrO 2 Mass ratio of total content (ZnO + Li 2 O) / (SiO 2 +ZrO 2 ) is between 1,600 and 3,000. Li 2 O content of ZnO and Li 2 Li as the mass ratio of the total O content 2 O / (ZnO+Li 2 O) is between 0.060 and 0.090, La 2 O 3 The content of ZnO and ZrO 2 Mass ratio La to total content 2 O 3 / (ZnO+ZrO) 2 ) is between 1.400 and 1.650, B 2 O 3 La content 2 O 3 Mass ratio B of the content 2 O 3 / La 2 O 3 The values ​​are 0.510 to 0.

590. Y 2 O 3 Li content 2 Mass ratio Y of the total content of O and ZnO 2 O 3 / (Li 2 The O + ZnO ratio is between 0.000 and 0.

020. The refractive index nd is 1.8020 to 1.8150. The Abbe number vd is between 38.5 and 42.

0. λ 80 The wavelength is 395-420 nm. λ 5 The wavelength is 330-350 nm. The glass transition temperature Tg is 530 to 557°C. The specific gravity is 4.35 to 4.

52. The liquidus temperature is between 980 and 1020°C.

9. The optical glass according to claim 1, satisfying at least one of the following conditions iii. SiO 2 The content is 4.00 to 7.00% by mass, B 2 O 3 The content is 17.00 to 22.00% by mass. The ZnO content is 17.00 to 20.00 mass%, La 2 O 3 The content is 34.00 to 37.00% by mass. Ta 2 O 5 The content is 0.00 to 0.50% by mass. Li 2 The O content is 1.30 to 2.00% by mass. Y 2 O 3 The content is 0.00 to 0.50% by mass. WO 3 The content is 4.00 to 6.50% by mass. ZrO 2 The content is 3.00 to 4.50% by mass. Nb 2 O 5 The content is 6.00 to 7.50% by mass. TiO 2 The content is 0.00 to 0.50% by mass. Sb 2 O 3 The content is 0.04 to 0.07% by mass, Gd 2 O 3 The content is 0.00 to 2.00% by mass. Nb 2 O 5 WO 3 , ZrO 2 and La 2 O 3 Total content of ZnO, Li 2 O, B 2 O 3 and SiO 2 Mass ratio of total content (Nb 2 O 5 +WO 3 +ZrO 2 +La 2 O 3 ) / (ZnO+Li 2 O+B 2 O 3 +SiO 2 ) is between 1.080 and 1.210, Nb 2 O 5 WO 3 and Ta 2 O 5 The total content of La 2 O 3 , Gd 2 O 3 and Y 2 O 3 Mass ratio of total content (Nb 2 O 5 +WO 3 +Ta 2 O 5 ) / (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) is between 0.330 and 0.370, SiO 2 SiO content 2 and B 2 O 3 Mass ratio of SiO to total content 2 / (SiO 2 +B 2 O 3 ) is between 0.180 and 0.220, Li 2 O, Na 2 O and K 2 Total O content of SiO 2 and B 2 O 3 Mass ratio of total content (Li 2 O + Na 2 O+K 2 O) / (SiO 2 +B 2 O 3 ) is between 0.045 and 0.080, The mass ratio of the total content of CaO, MgO, BaO, and SrO to the content of ZnO (CaO + MgO + BaO + SrO) / ZnO is between 0.000 and 0.

050. La 2 O 3 , Gd 2 O 3 and Y 2 O 3 Total content of SiO 2 and B 2 O 3 Mass ratio of total content (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) / (SiO 2 +B 2 O 3 ) is between 1.350 and 1.500, Y 2 O 3 La content 2 O 3 , Gd 2 O 3 and Y 2 O 3 Mass ratio Y of total content 2 O 3 / (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) is between 0.000 and 0.010, La 2 O 3 , Y 2 O 3 and ZrO 2 Total content of SiO 2 , B 2 O 3 and WO 3 Mass ratio of total content (La 2 O 3 +Y 2 O 3 +ZrO 2 ) / (SiO 2 +B 2 O 3 +WO 3 ) is between 1.200 and 1.400, Nb 2 O 5 and Ta 2 O 5 WO 3 and TiO 2 Mass ratio of total content (Nb 2 O 5 +Ta 2 O 5 ) / (WO 3 +TiO 2 ) is between 1.090 and 1.180, La 2 O 3 , Gd 2 O 3 and Y 2 O 3 The total content of ZnO and ZrO 2 Mass ratio of total content (La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ) / (ZnO+ZrO 2 ) is between 1.400 and 1.600, B 2 O 3 The content of ZnO and Li 2 Mass ratio B to total O content 2 O 3 / (ZnO+Li 2 O) is between 0.940 and 1.000, La 2 O 3 The content of ZnO and Y 2 O 3 Mass ratio La to total content 2 O 3 / (ZnO+Y 2 O 3 ) is between 1.700 and 2.

000. Li 2 Li content of O 2 O, Na 2 O and K 2 Li as the mass ratio of the total O content 2 O / (Li 2 O + Na 2 O+K 2 O) is between 0.900 and 1.000, iNb 2 O 5 WO 3 and TiO 2 The total content of La 2 O 3 Mass ratio of content (Nb 2 O 5 +WO 3 +TiO 2 ) / La 2 O 3 The values ​​are 0.330 to 0.

420. WO 3 Nb content 2 O 5 WO 3 and TiO 2 WO 3 / (Nb 2 O 5 +WO 3 +TiO 2 ) is between 0.400 and 0.500, Ta 2 O 5 Nb content 2 O 5 WO 3 and Ta 2 O 5 Mass ratio Ta to total content 2 O 5 / (Nb 2 O 5 +WO 3 +Ta 2 O 5 ) is between 0.000 and 0.050, Nb 2 O 5 WO 3 and Ta 2 O 5 Total content of SiO 2 , B 2 O 3 and La 2 O 3 Mass ratio of total content (Nb 2 O 5 +WO 3 +Ta 2 O 5 ) / (SiO 2 +B 2 O 3 +La 2 O 3 ) is between 0.150 and 0.230, ZnO and Li 2 Total O content of SiO 2 and ZrO 2 Mass ratio of total content (ZnO + Li 2 O) / (SiO 2 +ZrO 2 ) is between 1.800 and 2.

500. Li 2 O content of ZnO and Li 2 Li as the mass ratio of the total O content 2 O / (ZnO+Li 2 O) is 0.065 to 0.070, La 2 O 3 The content of ZnO and ZrO 2 Mass ratio La to total content 2 O 3 / (ZnO+ZrO) 2 ) is between 1.450 and 1.600, B 2 O 3 La content 2 O 3 Mass ratio B of the content 2 O 3 / La 2 O 3 The values ​​are 0.530 to 0.

570. Y 2 O 3 Li content 2 Mass ratio Y of the total content of O and ZnO 2 O 3 / (Li 2 The O + ZnO ratio is between 0.000 and 0.

010. The refractive index nd is 1.8030 to 1.8100. The Abbe number vd is between 39.0 and 41.

5. λ 80 The wavelength is 400-415 nm. λ 5 The wavelength is 335-345 nm. The glass transition temperature Tg is 535 to 555°C. The specific gravity is 4.40 to 4.

50. The liquidus temperature is between 990 and 1010°C.

10. An optical element comprising the optical glass described in any one of claims 1 to 9.

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