Optical glass and optical element

Abstract

Provided are an optical glass and an optical element having a small Abbe number νd and a high relative partial dispersion PC,t in the infrared wavelength region. In the optical glass, the content of SiO2 is 20 mass% or more, the content of B2O3 is 15 mass% or more, the content of ZrO2 is 5 mass% or more, the content of Nb2O5 exceeds 5 mass%, the mass ratio of the total content of Li2O, Na2O, and K2O (R2O) and the total content of MgO, CaO, SrO, BaO, and ZnO (R'O) to the total content of SiO2 and B2O3 [(R2O+R'O) / (SiO2+B2O3)] is 0.36 or less, the mass ratio of the content of B2O3 to the total content of ZrO2, Nb2O5, TiO2, WO3, Bi2O3, and Ta2O5 [B2O3 / (ZrO2+Nb2O5+TiO2+WO3+Bi2O3+Ta2O5)] is 0.74 or more, the total content of ZrO2, Nb2O5, TiO2, WO3, and Ta2O5 is 22 mass% or more, and the optical glass is substantially free of Pb.

Description

Technical Field

[0001] This invention relates to optical glass and optical elements having desired optical properties. Background Technology

[0002] Most surveillance cameras and burglarproof cameras have night vision capabilities, requiring imaging performance in the infrared wavelength region for their camera optical systems. Typically, for optical systems in SLR cameras and mirrorless cameras, which prioritize imaging performance in the visible short wavelength region, infrared imaging performance is not required.

[0003] To compensate for higher-order chromatic aberrations, two types of lenses are sometimes combined. Examples of these two types of lenses include combinations of convex and concave lenses, and combinations of low-dispersion and high-dispersion lenses. For these two types of lenses, it is desirable to have a large difference in Abbe number and a small difference in relative dispersion across different wavelength regions.

[0004] In both types of lenses mentioned above, fluorophosphate glass, which exhibits low and anomalous dispersion, is sometimes used as a lens. Compared to lenses used in combination with fluorophosphate glass, those with low and anomalous partial dispersion generally have larger Abbe numbers (νd) and higher relative partial dispersion (PC,t) in the infrared wavelength region. Therefore, to improve imaging performance in the near-infrared region, for the glass used as another lens in combination with a fluorophosphate glass lens, the Abbe number (νd) should be smaller than that of the fluorophosphate glass, and PC,t should be as close as possible to the value of the fluorophosphate glass; that is, ΔPC,t should be larger. It should be noted that, for the same reason, to improve imaging performance in the visible short-wavelength region, for the glass used as another lens in combination with a fluorophosphate glass lens, ΔPg,F should be smaller.

[0005] For highly dispersive glasses, increasing the content of glass components that contribute to high dispersion and thus reducing the Abbe number νd typically increases the relative partial dispersion Pg,F in the visible short-wavelength region and decreases the relative partial dispersion PC,t in the infrared wavelength region. Lenses made from such highly dispersive glasses, due to the increased difference in PC,t compared to the aforementioned fluorophosphate glass, cannot adequately compensate for chromatic aberration in the visible long-wavelength region, making them particularly unsuitable for use as lenses in night vision cameras.

[0006] Patent Documents 1 and 2 focus on anomalous partial dispersion and propose optical glasses with dispersion within a given range, but do not pay any attention to the relative partial dispersion PC,t in the infrared wavelength region.

[0007] Therefore, as a lens combined with a fluorophosphate glass lens to compensate for high-order chromatic aberrations throughout the near-infrared wavelength region, a lens made of glass with a high PC,t is required.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 10-130033

[0011] Patent Document 2: Japanese Patent Application Publication No. 2017-095348 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] This invention was made in view of the above-mentioned actual situation, and its purpose is to provide optical glass and optical elements with a small Abbe number νd and a relatively high partial dispersion PC,t in the infrared wavelength region. Based on the above objective, glass that does not excessively reduce the relative partial dispersion PC,t even when subjected to high dispersion was explored, resulting in the completion of this invention.

[0014] Methods for solving problems

[0015] The main points of this invention are as follows.

[0016] (1) An optical glass, wherein...

[0017] The SiO2 content is 20% by mass or more.

[0018] The B2O3 content is 15% by mass or more.

[0019] The ZrO2 content is 5% by mass or more.

[0020] The Nb2O5 content exceeds 5% by mass.

[0021] The total content of Li2O, Na2O, and K2O (R2O) and the total content of MgO, CaO, SrO, BaO, and ZnO (R'O), and the mass ratio of this content to the total content of SiO2 and B2O3 [(R2O+R'O) / (SiO2+B2O3)] should be less than 0.36.

[0022] The content of B2O3 and the mass ratio of its content to the total content of ZrO2, Nb2O5, TiO2, WO3, Bi2O3 and Ta2O5 [B2O3 / (ZrO2+Nb2O5+TiO2+WO3+Bi2O3+Ta2O5)] are greater than 0.74.

[0023] The total content of ZrO2, Nb2O5, TiO2, WO3 and Ta2O5 is above 22% by mass.

[0024] The optical glass is substantially free of Pb.

[0025] (2) An optical glass, wherein...

[0026] As a component of glass

[0027] Contains SiO2, B2O3, ZrO2 and Nb2O5.

[0028] It contains one or more selected from Li₂O, Na₂O, and K₂O.

[0029] The ΔPC,t of the optical glass is 0.0250 or higher.

[0030] (3) An optical glass, wherein...

[0031] Si 4+ The content is 10% or more cationic.

[0032] B 3+ The content is 20% or more cationic.

[0033] Si 4+ and B 3+ Total content [Si] 4+ +B 3+ The percentage is 50% or higher.

[0034] B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The value is above 0.44.

[0035] Li + Na + and K + The total content R, and the total content R and Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total cation ratio of the total content R' [R / (R+R')] is 0.55 or higher.

[0036] Nb 5+ The content exceeds 0 cation% and is below 11.5 cation%

[0037] The optical glass satisfies one or more of the following conditions (i) and (ii).

[0038] (i)Zr 4+ The content of R' and Nb is related to the total content mentioned above. 5+ Ti 4+ W 6+ Bi 3+ and Ta 5+The total content of cation ratio [Zr 4+ / (R'+Nb 5+ +Ti 4+ +W 6+ +Bi 3+ +Ta 5+ The value is above 0.17.

[0039] (ii)Zr 4+ and Ta 5+ The total content is the same as the total content of R' and Nb mentioned above. 5+ Ti 4+ W 6+ and Bi 3+ The total content of cation ratio [(Zr 4+ +Ta 5+ ) / (R'+Nb 5+ +Ti 4+ +W 6+ +Bi 3+ The value is above 0.25.

[0040] (4) The optical glass according to (3), wherein Zr 4+ and Ta 5+ The total content is less than 8.5% cationic.

[0041] (5) The optical glass according to (3) or (4), wherein Zr 4+ and Ta 5+ Total content and R', Nb 5+ Ti 4+ W 6+ and Bi 3+ The total content of cation ratio [(Zr 4+ +Ta 5+ ) / (R'+Nb 5+ +Ti 4+ +W 6+ +Bi 3+ The value of R' is below 3.10, and R' is Mg. 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content.

[0042] (6) An optical glass, wherein...

[0043] As a component of glass

[0044] Contains Si 4+ B 3+ Zr 4+ and Nb 5+ ,

[0045] And contains selected from Li + Na + and K + One or more of them

[0046] The ΔPC,t of the optical glass is 0.0250 or higher.

[0047] (7) An oxide optical glass, wherein...

[0048] Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ Total content [Nb] 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The content is above 6.5% cations.

[0049] Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The value is above 0.55.

[0050] Zr 4+ The content of Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Zr 4+ / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The value is above 0.4.

[0051] Si 4+ B 3+ Li + Na + K + and Zr 4+ Total content and Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [(Si 4+ +B 3+ +Li + +Na + +K + +Zr 4+ ) / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The value is above 8.6.

[0052] The oxide optical glass is substantially free of Pb and As.

[0053] The PC,t of the oxide optical glass satisfies the following equation [2-2],

[0054] PC,t≥0.5711+0.004667×νd···[2-2]

[0055] The oxide optical glass satisfies one or more of the following conditions (I) to (IV).

[0056] (I)Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The value is below 0.85.

[0057] (II)Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4++B 3+ The value is below 0.97.

[0058] Li + Na + Mg 2+ and Ca 2+ Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +Mg 2+ +Ca 2+ ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The value is above 0.75.

[0059] (III)B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The value is above 0.46.

[0060] (IV)Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+The value is above 0.75.

[0061] B 3+ and Li + Total content and Si 4+ Na + and K + The total content of cation ratio [(B 3+ +Li + ) / (Si 4+ +Na + +K + The value is above 0.31.

[0062] (8) An oxide optical glass, wherein...

[0063] Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ Total content [Nb] 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The content is above 6.5% cations.

[0064] B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The value is above 0.41 and below 1.

[0065] Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+The value is above 0.55.

[0066] Zr 4+ The content of Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Zr 4+ / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The value is above 0.4.

[0067] Si 4+ B 3+ Li + Na + K + and Zr 4+ Total content and Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [(Si 4+ +B 3+ +Li + +Na + +K + +Zr 4+ ) / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The value is above 8.6.

[0068] The oxide optical glass is substantially free of Pb and As.

[0069] The oxide optical glass satisfies one or more of the following conditions (I) to (IV).

[0070] (I)Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The value is below 0.85.

[0071] (II)Li +Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The value is below 0.97.

[0072] Li + Na + Mg 2+ and Ca 2+ Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +Mg 2+ +Ca 2+ ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The value is above 0.75.

[0073] (III)B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The value is above 0.46.

[0074] (IV)Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K+ ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The value is above 0.75.

[0075] B 3+ and Li + Total content and Si 4+ Na + and K + The total content of cation ratio [(B 3+ +Li + ) / (Si 4+ +Na + +K + The value is above 0.31.

[0076] (9) An oxide optical glass, wherein...

[0077] As a component of glass

[0078] Contains Si 4+ B 3+ Zr 4+ and Nb 5+ ,

[0079] And contains selected from Li + Na + and K + One or more of them

[0080] The ΔPg,F and ΔPC,t of the oxide optical glass satisfy either of the following (i) or (ii).

[0081] (i) When ΔPg,F is greater than -0.0037, ΔPC,t ≥ 2.875 × ΔPg,F + 0.031.

[0082] (ii) When ΔPg,F is below -0.0037, ΔPC,t ≥ 4.750 × ΔPg,F + 0.038.

[0083] (10) An oxide optical glass, wherein,

[0084] As a component of glass

[0085] Contains Si 4+ B 3+ Zr 4+ and Nb 5+ ,

[0086] And contains selected from Li + Na + and K + One or more of them

[0087] The PC,t of the oxide optical glass satisfies the following equation [2-1],

[0088] PC,t≥0.5661+0.004667×νd···[2-1].

[0089] (11) The oxide optical glass according to (10) has Pg,F satisfying the following formula [1-1],

[0090] Pg,F≤0.6463-0.001802×νd···[1-1].

[0091] (12) The optical glass according to any one of (7) to (11), wherein,

[0092] Nb 5+ and Ti 4+ Total content and Nb 5+ Ti 4+ W 6+ and Bi 3+ The total content of cation ratio [(Nb 5+ +Ti 4+ ) / (Nb 5+ +Ti 4+ +W 6+ +Bi 3+ The value is above 0.5.

[0093] (13) An optical element made of any one of the optical glass described in (1) to (12) above.

[0094] The effects of the invention

[0095] According to the present invention, optical glass and optical elements with a small Abbe number νd and relatively high partial dispersion PC,t in the infrared wavelength region can be provided. Detailed Implementation

[0096] The embodiments of the present invention will be described below. It should be noted that the content of the glass component can be quantified by known methods, such as inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS).

[0097] Furthermore, in this specification, the terms "thermal stability" and "stability upon reheating" both refer to the degree of difficulty in crystallization within the glass. Specifically, "thermal stability" refers to the degree of difficulty in crystallization when molten glass solidifies, while "stability upon reheating" refers to the degree of difficulty in crystallization when solidified glass is reheated, such as during reheat pressing.

[0098] Unless otherwise specified, the refractive index in this specification refers to the refractive index nd under helium d rays (wavelength 587.56 nm).

[0099] The optical glass of the present invention will be described below in three embodiments: the first embodiment (the first-1 embodiment and the first-2 embodiment), the second embodiment (the second-1 embodiment and the second-2 embodiment), and the third embodiment (the third-1 embodiment, the third-2 embodiment, the third-3 embodiment, and the third-4 embodiment).

[0100] Implementation Method 1

[0101] In the first embodiment (Embodiments 1-1 and 1-2), unless otherwise specified, the glass composition of the optical glass is expressed on an oxide basis. Here, "oxide-based glass composition" refers to the glass composition obtained by converting substances that exist in the optical glass in the form of oxides after the glass raw material has completely decomposed during melting. Each glass component is conventionally described as SiO2, TiO2, etc. In the first embodiment (Embodiments 1-1 and 1-2), unless otherwise specified, the content and total content of the glass components are on a mass basis, and "%" refers to "mass %". Furthermore, in this specification and the present invention, a content of 0% for a constituent component means that the constituent component is substantially not present, but is permitted to be present at an unavoidable level of impurities.

[0102] Implementation Method 1-1

[0103] In embodiment 1-1, the glass composition was designed based on the following criteria. That is, <1> While containing large amounts of SiO2 and B2O3, which are components that increase the relative partial dispersion PC,t in the infrared wavelength region. <2> By appropriately replacing a portion of SiO2 with B2O3, high dispersion can be achieved without significantly reducing PC,t. <3> With the aim of further improving solubility and formability through high dispersion and low viscosity, alkali metal and alkaline earth metal oxides are appropriately introduced. <4> By minimizing the amount of high dispersion components required to obtain the desired Abbe number and which also reduce PC,t, Nb2O5, which can relatively suppress the reduction of PC,t, particularly in high dispersion components, and ZrO2, which can simultaneously achieve suppression of PC,t reduction and improvement of the chemical durability of the glass, an optical glass with a small Abbe number νd and a relatively high partial dispersion PC,t in the infrared wavelength region is completed. The optical glass of the first embodiment is described below.

[0104] In the optical glass of the first-1 embodiment,

[0105] The SiO2 content is above 20%.

[0106] The B2O3 content is above 15%.

[0107] The ZrO2 content is above 5%.

[0108] The Nb2O5 content exceeds 5%.

[0109] The total content of Li2O, Na2O, and K2O (R2O) and the total content of MgO, CaO, SrO, BaO, and ZnO (R'O), and the mass ratio of this content to the total content of SiO2 and B2O3 [(R2O+R'O) / (SiO2+B2O3)] should be less than 0.36.

[0110] The content of B2O3 and the mass ratio of its content to the total content of ZrO2, Nb2O5, TiO2, WO3, Bi2O3 and Ta2O5 [B2O3 / (ZrO2+Nb2O5+TiO2+WO3+Bi2O3+Ta2O5)] are greater than 0.74.

[0111] The total content of ZrO2, Nb2O5, TiO2, WO3 and Ta2O5 is above 22%.

[0112] Furthermore, this optical glass does not actually contain Pb.

[0113] In the optical glass of the first-1 embodiment, the SiO2 content is 20% or more. The lower limit of the SiO2 content is preferably 24%, and more preferably 26% and 28% in that order. Furthermore, the upper limit of the SiO2 content is preferably 50%, and more preferably 45%, 40%, and 35% in that order. SiO2 is a network-forming component of the glass. By setting the SiO2 content within the above range, the relative partial dispersion (PC,t) in the infrared wavelength region can be increased, thereby improving chemical durability. When the SiO2 content is too low, the relative partial dispersion (PC,t) in the infrared wavelength region decreases, and there is a risk of reduced thermal stability and chemical durability of the glass. When the SiO2 content is too high, there is a risk of reduced solubility of the glass, and there is a risk of increased viscosity of the molten glass leading to poor formability.

[0114] In the optical glass of the first-1 embodiment, the content of B2O3 is 15% or more. The lower limit of the B2O3 content is preferably 17%, and more preferably 19% and 21% in that order. Furthermore, the upper limit of the B2O3 content is preferably 50%, and more preferably 45%, 40%, and 35% in that order. B2O3 is a network-forming component of the glass. By setting the B2O3 content within the above range, the relative partial dispersion (PC,t) in the infrared wavelength region can be improved. When the B2O3 content is too low, the relative partial dispersion (PC,t) in the infrared wavelength region decreases, and there is a risk of reduced thermal stability of the glass. When the B2O3 content is too high, there is a risk of reduced chemical durability of the glass.

[0115] In the optical glass of the first-1 embodiment, the ZrO2 content is 5% or more. The lower limit of the ZrO2 content is preferably 6.5%, and more preferably 8.0% and 9.5% in that order. Furthermore, the upper limit of the ZrO2 content is preferably 30%, and more preferably 25%, 20%, and 15% in that order. By setting the ZrO2 content within the above range, the relative partial dispersion PC,t in the infrared wavelength region can be improved, thereby improving chemical durability. If the ZrO2 content is too low, there is a risk of reduced chemical durability. If the ZrO2 content is too high, there is a risk of increased liquidus temperature LT, and also a risk of reduced stability upon reheating.

[0116] In the optical glass of the first-1 embodiment, the Nb2O5 content exceeds 5%. The lower limit of the Nb2O5 content is preferably 6.5%, and more preferably 8.0% and 9.5% in that order. Furthermore, the upper limit of the Nb2O5 content is preferably 30%, and more preferably 25%, 20%, and 15% in that order. By maintaining the Nb2O5 content within the above range, high dispersion can be maintained while suppressing the decrease in relative partial dispersion (PC,t) in the infrared wavelength region. If the Nb2O5 content is too low, there is a risk that high dispersion cannot be maintained. If the Nb2O5 content is too high, there is a risk that the relative partial dispersion (PC,t) in the infrared wavelength region will decrease.

[0117] In the optical glass of the first-1 embodiment, the mass ratio of the total content of Li2O, Na2O, and K2O (R2O) and the total content of MgO, CaO, SrO, BaO, and ZnO (R'O) to the total content of SiO2 and B2O3 [(R2O+R'O) / (SiO2+B2O3)] is 0.36 or less. The upper limit of this mass ratio is preferably 0.35, and more preferably 0.34 or 0.33 in that order. Furthermore, the lower limit of this mass ratio is preferably 0.05, and more preferably 0.10, 0.15, or 0.20 in that order. By setting this mass ratio within the above range, the relative partial dispersion (PC,t) in the infrared wavelength region can be improved, thereby improving chemical durability.

[0118] It should be noted that in this specification, the total content of Li2O, Na2O and K2O is sometimes referred to as R2O, and the total content of MgO, CaO, SrO, BaO and ZnO is sometimes referred to as R'O.

[0119] In the optical glass of the first-1 embodiment, the content of B2O3 and the mass ratio of its total content to ZrO2, Nb2O5, TiO2, WO3, Bi2O3, and Ta2O5 [B2O3 / (ZrO2+Nb2O5+TiO2+WO3+Bi2O3+Ta2O5)] is 0.74 or more. The lower limit of this mass ratio is preferably 0.84, and more preferably in the order of 0.94 and 1.04. Furthermore, the upper limit of this mass ratio is preferably 3.0, and more preferably in the order of 2.5, 2.0, and 1.5. By setting this mass ratio within the above range, the relative partial dispersion PC,t in the infrared wavelength region can be improved.

[0120] In the optical glass of Embodiment 1-1, the total content of ZrO2, Nb2O5, TiO2, WO3, and Ta2O5 [ZrO2+Nb2O5+TiO2+WO3+Ta2O5] is 22% or more. The lower limit of this total content is preferably 22.5%, and more preferably in the order of 23.0% and 23.5%. Furthermore, the upper limit of this total content is preferably 40%, and more preferably in the order of 35%, 30%, and 25%. By setting the total content within the above range, the refractive index nd can be increased, and the Abbe number νd can be within the desired range.

[0121] The optical glass of the first-1 embodiment substantially does not contain Pb, which is a component with potential environmental burden. That is, the Pb content is preferably 0% when converted to oxides. Furthermore, As and Th are also components with potential environmental burden, similar to Pb. Therefore, the content of each of As and Th is preferably 0 to 0.1% when converted to oxides, which can be 0 to 0.05% or 0 to 0.01%. The content of each of As and Th is preferably 0% when converted to oxides. That is, As and Th are preferably substantially absent.

[0122] The preferred content of the glass component in the optical glass of the first-1 embodiment is shown below.

[0123] In the optical glass of the first-1 embodiment, the lower limit of the total content of SiO2 and B2O3 [SiO2+B2O3] is preferably 35%, and more preferably in the order of 40%, 45%, and 50%. Furthermore, the upper limit of this total content is preferably 70%, and more preferably in the order of 65%, 60%, and 57%. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and maintaining the thermal stability of the glass, it is preferable that the total content is within the above-mentioned range. If the total content is too low, the relative partial dispersion PC,t in the infrared wavelength region decreases, and there is a risk that the thermal stability and chemical durability of the glass cannot be maintained. If the total content is too high, there is a risk that the viscosity of the molten glass increases, resulting in poor formability. Additionally, there is a risk of a decrease in the refractive index.

[0124] In the optical glass of the first-1 embodiment, the lower limit of the mass ratio of B2O3 content to the total content of SiO2 and B2O3 [B2O3 / (SiO2+B2O3)] is preferably 0.20, and more preferably in the order of 0.25, 0.30, and 0.35. Furthermore, the upper limit of this mass ratio is preferably 0.65, and more preferably in the order of 0.60, 0.55, and 0.50. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, it is preferable that this mass ratio is within the above-mentioned range. If this mass ratio is too small, there is a risk of a decrease in the relative partial dispersion PC,t. If this mass ratio is too large, there is a risk of a decrease in the chemical durability of the glass.

[0125] In the optical glass of the first-1 embodiment, the lower limit of the mass ratio [R2O / (R2O+R'O)] of the total content R2O of Li2O, Na2O, and K2O to the total content R'O of MgO, CaO, SrO, BaO, and ZnO is preferably 0.20, and more preferably in the order of 0.25, 0.30, and 0.35. Furthermore, the upper limit of this mass ratio is preferably 1, and more preferably in the order of 0.95, 0.90, and 0.85. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and reducing the viscosity of the molten glass to improve formability, it is preferable that this mass ratio is within the above range. If the mass ratio is too small, there is a risk of a decrease in the relative partial dispersion PC,t. If the mass ratio is too large, the thermal stability of the glass decreases, and there is a risk of a decrease in the refractive index nd.

[0126] In the optical glass of the first-1 embodiment, the lower limit of the mass ratio of ZrO2 content to the total content of MgO, CaO, SrO, BaO, and ZnO (R'O, Nb2O5, TiO2, WO3, Bi2O3, and Ta2O5) [ZrO2 / (R'O+Nb2O5+TiO2+WO3+Bi2O3+Ta2O5)] is preferably 0.20, and more preferably in the order of 0.25, 0.30, and 0.35. Furthermore, the upper limit of this mass ratio is preferably 1.5, and more preferably in the order of 1.25, 1.00, and 0.70. From the viewpoint of improving chemical durability, increasing the refractive index nd, and maintaining high dispersion, it is preferable that this mass ratio is within the above range. If the mass ratio is too small, there is a risk of a decrease in the refractive index nd, and there is also a risk of a decrease in the chemical durability of the glass. If the mass ratio is too large, there is a risk of an increase in the liquidus temperature LT, and there is also a risk of a decrease in stability upon reheating.

[0127] In the optical glass of the first-1 embodiment, the lower limit of the mass ratio of the total content of ZrO2 and Ta2O5 to the total content of MgO, CaO, SrO, BaO and ZnO, R'O, Nb2O5, TiO2, Bi2O3 and WO3 [(ZrO2+Ta2O5) / (R'O+Nb2O5+TiO2+Bi2O3+WO3)] is preferably 0.1, and more preferably in the order of 0.2, 0.3 and 0.4. Furthermore, the upper limit of this mass ratio is preferably 1.3, and more preferably in the order of 1.1, 0.9 and 0.7. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the refractive index nd, maintaining high dispersion, and maintaining the chemical durability of the glass, it is preferable that the mass ratio is within the above range. If the mass ratio is too small, there is a risk of a decrease in the refractive index nd, and there is also a risk of a decrease in the chemical durability of the glass. If the mass ratio is too large, there is a risk of a decrease in the thermal stability of the glass.

[0128] In the optical glass of the first-1 embodiment, the lower limit of the total content of ZrO2 and Ta2O5 [ZrO2 + Ta2O5] is preferably 6%, and more preferably in the order of 7%, 8%, and 9%. Furthermore, the upper limit of this total content is preferably 20%, and more preferably in the order of 18%, 16%, and 14%. From the viewpoint of maintaining the thermal stability of the glass, it is preferable that the total content is within the above-mentioned range. If the total content is too low, there is a risk of reduced chemical durability of the glass. If the total content is too high, there is a risk of reduced thermal stability of the glass, and also a risk of increased raw material costs.

[0129] Regarding the content and ratio of glass components other than those described above in the optical glass of Embodiment 1-1, non-limiting examples are shown below.

[0130] In the optical glass of the first-1 embodiment, the upper limit of the P2O5 content is preferably 20%, and more preferably in the order of 15%, 10%, and 5%. Furthermore, the lower limit of the P2O5 content is preferably 0%, and more preferably in the order of 0.1%, 0.5%, and 1%. The P2O5 content may also be 0%. By keeping the P2O5 content within the above range, the thermal stability of the glass can be maintained.

[0131] In the optical glass of the first-1 embodiment, the upper limit of the Al2O3 content is preferably 10%, and more preferably in the order of 8%, 6%, 4%, 2%, 1.75%, 1.50%, and 1.25%. Furthermore, the lower limit of the Al2O3 content is preferably 0%, and more preferably in the order of 0.25%, 0.50%, and 0.75%. The Al2O3 content may also be 0%. Al2O3 has the effect of suppressing phase separation of the glass by containing an appropriate amount. On the other hand, from the viewpoint of maintaining the thermal stability of the glass, it is preferable that the Al2O3 content is within the above-mentioned range.

[0132] In the optical glass of the first-1 embodiment, the lower limit of the total content of SiO2, B2O3, and Al2O3 [SiO2+B2O3+Al2O3] is preferably 42%, and more preferably in the order of 45%, 48%, and 51%. Furthermore, the upper limit of this total content is preferably 74%, and more preferably in the order of 71%, 68%, and 65%. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, maintaining the thermal stability of the glass, and its stability upon reheating, it is preferable that the total content is within the above-mentioned range.

[0133] In the glass of the first-1 embodiment, the upper limit of the Li2O content is preferably 20%, and more preferably in the order of 15%, 10%, and 6%. Furthermore, the lower limit of the Li2O content is preferably 0%, and more preferably in the order of 1%, 2%, and 3%. The Li2O content can also be 0%. Li2O is a component that contributes to the reduction of glass viscosity, and among alkali metals, it has a significant effect on improving the relative partial dispersion PC,t in the infrared wavelength region. Excessive Li2O content may lead to decreased stability upon reheating. Conversely, insufficient Li2O content may lead to increased glass viscosity.

[0134] In the glass of the first-1 embodiment, the upper limit of the Na2O content is preferably 20%, and more preferably in the order of 18%, 16%, and 14%. Furthermore, the lower limit of the Na2O content is preferably 0%, and more preferably in the order of 1%, 2%, and 3%. Like Li2O, Na2O is a component that contributes to reducing the viscosity of the glass. Excessive Na2O content may lead to decreased stability during reheating. Conversely, insufficient Na2O content may lead to increased viscosity of the glass.

[0135] In the optical glass of the first-1 embodiment, the upper limit of the K2O content is preferably 20%, and more preferably in the order of 18%, 16%, and 14%. Furthermore, the lower limit of the K2O content is preferably 0%, and more preferably in the order of 1%, 2%, and 3%. The K2O content may also be 0%.

[0136] K₂O has the effect of lowering the liquidus temperature and improving the thermal stability of glass. On the other hand, when the K₂O content is too high, the chemical durability, weather resistance, and stability upon reheating decrease. Therefore, the K₂O content is preferably within the range described above.

[0137] In the optical glass of the first-1 embodiment, the upper limit of the total content of Li2O, Na2O, and K2O, R2O [Li2O+Na2O+K2O], is preferably 25%, and more preferably in the order of 20%, 15%, and 10%. Furthermore, the lower limit of the total content of R2O is preferably 1%, and more preferably in the order of 2.5%, 4.0%, and 5.5%. From the viewpoint of suppressing the decrease in stability upon reheating, it is preferable that the total content of R2O is within the above-mentioned range.

[0138] In the optical glass of the first-1 embodiment, the upper limit of the mass ratio of Li2O content to the total content R2O of Li2O, Na2O, and K2O [Li2O / R2O] is preferably 1, and more preferably in the order of 0.8, 0.6, and 0.4. Furthermore, the lower limit of this mass ratio is preferably 0, and more preferably in the order of 0.1, 0.2, and 0.3. This mass ratio may also be 0. From the viewpoint of suppressing the decrease in stability upon reheating, it is preferable that the mass ratio is within the above-mentioned range.

[0139] In the optical glass of the first-1 embodiment, the upper limit of the mass ratio of Na2O content to the total content of Li2O, Na2O, and K2O, R2O [Na2O / R2O] is preferably 1, and more preferably in the order of 0.9, 0.8, and 0.7. Furthermore, the lower limit of this mass ratio is preferably 0, and more preferably in the order of 0.1, 0.2, and 0.3. This mass ratio may also be 0. From the viewpoint of suppressing the decrease in stability upon reheating, it is preferable that this mass ratio is within the above-mentioned range.

[0140] In the optical glass of the first-1 embodiment, the upper limit of the mass ratio of K2O content to the total content of Li2O, Na2O, and K2O, R2O [K2O / R2O] is preferably 1, and more preferably in the order of 0.8, 0.6, and 0.4. Furthermore, the lower limit of this mass ratio is preferably 0, and more preferably in the order of 0.1, 0.2, and 0.3. This mass ratio may also be 0. From the viewpoint of suppressing the decrease in stability upon reheating, it is preferable that the mass ratio is within the above-mentioned range.

[0141] In the optical glass of the first-1 embodiment, the upper limit of the Cs₂O content is preferably 20%, and more preferably in the order of 15%, 10%, and 5%. The lower limit of the Cs₂O content is preferably 0%. The Cs₂O content may also be 0%.

[0142] Cs₂O improves the thermal stability of glass, but increasing its content may reduce chemical durability and weather resistance. Therefore, the preferred Cs₂O content is within the range described above.

[0143] In the optical glass of the first-1 embodiment, the upper limit of the TiO2 content is preferably 30%, and more preferably in the order of 15%, 8%, 6%, and 4%. Furthermore, the lower limit of the TiO2 content is preferably 0%. The TiO2 content may also be 0%. By setting the TiO2 content within the above range, the desired optical constant can be achieved, and the increase in specific gravity is suppressed.

[0144] In the optical glass of the first-1 embodiment, the upper limit of the WO3 content is preferably 30%, and more preferably in the order of 15%, 8%, 6%, 4%, 2%, and 1%. The lower limit of the WO3 content is preferably 0%. The WO3 content may also be 0%. From the viewpoint of improving transmittance, suppressing the decrease of relative partial dispersion PC,t in the infrared wavelength region, and reducing specific gravity, it is preferable to make the WO3 content within the above-mentioned range.

[0145] In the optical glass of the first-1 embodiment, the upper limit of the Bi2O3 content is preferably 30%, and more preferably in the order of 15%, 10%, and 8%. Furthermore, the lower limit of the Bi2O3 content is preferably 0%, and more preferably in the order of 2%, 4%, and 6%. The Bi2O3 content may also be 0%. From the viewpoint of improving transmittance and reducing specific gravity, and also from the viewpoint of reducing damage to platinum manufacturing equipment, it is preferable to have the Bi2O3 content within the above-mentioned range.

[0146] In the optical glass of the first-1 embodiment, the upper limit of the Ta2O5 content is preferably 20%, and more preferably in the order of 15%, 10%, 8%, 6%, 4%, and 2%. Furthermore, the lower limit of the Ta2O5 content is preferably 0%, and more preferably in the order of 0.5%, 1%, and 1.5%. The Ta2O5 content may also be 0%.

[0147] Ta₂O₅ is a component that imparts high refractive index and low dispersion to glass, improving the relative partial dispersion (PC,t) in the infrared wavelength region. However, increasing the Ta₂O₅ content increases raw material costs. Furthermore, there is a risk of increased specific gravity. Therefore, the preferred Ta₂O₅ content is within the range described above.

[0148] In the optical glass of the first-1 embodiment, the upper limit of the total content of Nb2O5, TiO2, WO3, and Bi2O3 [Nb2O5+TiO2+WO3+Bi2O3] is preferably 40%, and more preferably in the order of 35%, 30%, and 25%. The lower limit of this total content is preferably 5%, and more preferably in the order of 7%, 9%, and 11%. From the viewpoint of maintaining a high refractive index, it is preferable that the total content is within the above-mentioned range.

[0149] In the optical glass of the first-1 embodiment, the upper limit of the total content of Nb2O5, TiO2, WO3, Bi2O3, and Ta2O5 [Nb2O5+TiO2+WO3+Bi2O3+Ta2O5] is preferably 40%, and more preferably in the order of 35%, 30%, and 25%. The lower limit of this total content is preferably 5%, and more preferably in the order of 7%, 9%, and 11%. From the viewpoint of maintaining a high refractive index and a desired Abbe number νd, it is preferable that the total content is within the above-mentioned range.

[0150] In the optical glass of the first-1 embodiment, the upper limit of the total content of ZrO2, Nb2O5, TiO2, WO3, Bi2O3, and Ta2O5 [ZrO2+Nb2O5+TiO2+WO3+Bi2O3+Ta2O5] is preferably 50%, and more preferably in the order of 45%, 40%, and 37%. The lower limit of this total content is preferably 10%, and more preferably in the order of 15%, 20%, and 23%. From the viewpoint of maintaining a high refractive index, it is preferable that the total content is within the above-mentioned range.

[0151] In the optical glass of the first-1 embodiment, the upper limit of the total content of ZrO2 and Nb2O5 [ZrO2+Nb2O5] is preferably 50%, and more preferably in the order of 45%, 40%, and 37%. The lower limit of this total content is preferably 10%, and more preferably in the order of 15%, 20%, and 23%. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and maintaining high dispersion, it is preferable that the total content is within the above-mentioned range.

[0152] In the optical glass of the first-1 embodiment, the upper limit of the total content of Nb2O5, TiO2, WO3, and Ta2O5 [Nb2O5+TiO2+WO3+Ta2O5] is preferably 40%, and more preferably in the order of 35%, 30%, and 25%. The lower limit of this total content is preferably 5%, and more preferably in the order of 7%, 9%, and 11%. From the viewpoint of maintaining a high refractive index and a desired Abbe number νd, it is preferable that the total content is within the above-mentioned range.

[0153] In the optical glass of the first-1 embodiment, the upper limit of the mass ratio of Nb2O5 content to the total content of Nb2O5, TiO2, WO3, and Ta2O5 [Nb2O5 / (Nb2O5+TiO2+WO3+Ta2O5)] is preferably 1, and more preferably in the order of 0.95, 0.90, and 0.85. The lower limit of this mass ratio is preferably 0, and more preferably in the order of 0.50, 0.60, 0.70, and 0.80. This mass ratio can be 1. From the viewpoint of maintaining a high refractive index, it is preferable that this mass ratio is within the above-mentioned range.

[0154] In the optical glass of the first-1 embodiment, the upper limit of the mass ratio of Ta2O5 content to the total content of Nb2O5, TiO2, WO3, and Ta2O5 [Ta2O5 / (Nb2O5+TiO2+WO3+Ta2O5)] is preferably 1, and more preferably in the order of 0.5, 0.3, and 0.1. The lower limit of this mass ratio is preferably 0, and more preferably in the order of 0.01, 0.03, and 0.05. The mass ratio may also be 0. From the viewpoint of suppressing the increase in the raw material cost of the glass, it is preferable to make the mass ratio within the above range.

[0155] In the optical glass of the first-1 embodiment, the upper limit of the mass ratio of TiO2 content to the total content of Nb2O5, TiO2, WO3, and Ta2O5 [TiO2 / (Nb2O5+TiO2+WO3+Ta2O5)] is preferably 1, and more preferably in the order of 0.5, 0.3, and 0.1. The lower limit of this mass ratio is preferably 0, and more preferably in the order of 0.01, 0.03, and 0.05. This mass ratio may also be 0. From the viewpoint of maintaining a high refractive index, it is preferable that this mass ratio is within the above-mentioned range.

[0156] In the optical glass of the first-1 embodiment, the upper limit of the mass ratio of ZrO2 content to the total content of ZrO2, Nb2O5, TiO2, WO3, and Ta2O5 [ZrO2 / (ZrO2+Nb2O5+TiO2+WO3+Ta2O5)] is preferably 0.8, and more preferably in the order of 0.7, 0.6, and 0.5. The lower limit of this mass ratio is preferably 0.10, and more preferably in the order of 0.20, 0.25, and 0.30. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and maintaining high dispersion, it is preferable to make this mass ratio within the above range.

[0157] In the optical glass of the first-1 embodiment, the upper limit of the mass ratio of Nb2O5 content to the total content of ZrO2, Nb2O5, TiO2, WO3, and Ta2O5 [Nb2O5 / (ZrO2+Nb2O5+TiO2+WO3+Ta2O5)] is preferably 0.95, and more preferably in the order of 0.9, 0.8, and 0.7. The lower limit of this mass ratio is preferably 0.1, and more preferably in the order of 0.2, 0.3, 0.4, and 0.5. This mass ratio can be 1. From the viewpoint of maintaining high dispersion, it is preferable that this mass ratio is within the above-mentioned range.

[0158] In the optical glass of the first-1 embodiment, the upper limit of the mass ratio of Ta2O5 content to the total content of ZrO2, Nb2O5, TiO2, WO3, and Ta2O5 [Ta2O5 / (ZrO2+Nb2O5+TiO2+WO3+Ta2O5)] is preferably 0.5, and more preferably in the order of 0.4, 0.3, and 0.2. The lower limit of this mass ratio is preferably 0, and more preferably in the order of 0.05, 0.10, and 0.15. This mass ratio may also be 0. From the viewpoint of suppressing the increase in raw material costs, it is preferable to make this mass ratio within the above range.

[0159] In the optical glass of the first-1 embodiment, the upper limit of the mass ratio of TiO2 content to the total content of ZrO2, Nb2O5, TiO2, WO3, and Ta2O5 [TiO2 / (ZrO2+Nb2O5+TiO2+WO3+Ta2O5)] is preferably 0.5, and more preferably in the order of 0.4, 0.3, and 0.2. The lower limit of this mass ratio is preferably 0, and more preferably in the order of 0.05, 0.10, and 0.15. This mass ratio may also be 0. From the viewpoint of maintaining high dispersion, it is preferable that this mass ratio is within the above-mentioned range.

[0160] In the optical glass of the first-1 embodiment, the upper limit of the MgO content is preferably 20%, and more preferably in the order of 15%, 10%, and 5%. Furthermore, the lower limit of the MgO content is preferably 0%. The MgO content may also be 0%.

[0161] MgO is a component of alkaline earth metals that improves the relative partial dispersion (PC,t) in the infrared wavelength region. However, as the MgO content increases, the high dispersion is compromised, and there is a risk of reduced thermal stability and devitrification resistance of the glass. Therefore, the MgO content is preferably within the range described above.

[0162] In the optical glass of the first-1 embodiment, the upper limit of the CaO content is preferably 20%, and more preferably in the order of 15%, 10%, and 5%. Furthermore, the lower limit of the CaO content is preferably 0%, and more preferably in the order of 3.0%, 4.0%, and 4.5%. The CaO content may also be 0%.

[0163] CaO is a component of alkaline earth metals that improves the relative partial dispersion (PC,t) in the infrared wavelength region. However, as the CaO content increases, the high dispersion is compromised, and there is a risk of reduced thermal stability and devitrification resistance of the glass. Therefore, the CaO content is preferably within the range described above.

[0164] In the optical glass of the first-1 embodiment, the upper limit of the SrO content is preferably 30%, and more preferably in the order of 20%, 10%, and 5%. Furthermore, the lower limit of the SrO content is preferably 0%. The SrO content may also be 0%.

[0165] SrO is a component in alkaline earth metals that increases the refractive index. However, as the SrO content increases, high dispersion is compromised, and there is a risk of a decrease in the relative partial dispersion PC,t in the infrared wavelength region. Therefore, the SrO content is preferably within the range described above.

[0166] In the optical glass of the first-1 embodiment, the upper limit of the BaO content is preferably 30%, and more preferably in the order of 25%, 20%, 15%, and 13%. The lower limit of the BaO content is preferably 0%, and more preferably in the order of 5%, 8%, and 10%. The BaO content may also be 0%.

[0167] BaO is a component that increases the refractive index and also lowers the liquidus temperature, thus improving the thermal stability of glass. However, excessive BaO content impairs high dispersion and poses a risk of reducing the relative partial dispersion (PC,t) in the infrared wavelength region. Conversely, insufficient BaO content reduces the refractive index (nd) and may decrease the thermal stability and devitrification resistance of the glass. Therefore, the preferred BaO content is within the range described above.

[0168] In the optical glass of the first-1 embodiment, the upper limit of the ZnO content is preferably 20%, and more preferably in the order of 15%, 10%, 5%, 4%, 3%, and 2%. Furthermore, the lower limit of the ZnO content is preferably 0%, and more preferably in the order of 0.5%, 0.8%, and 1%. The ZnO content may also be 0%.

[0169] ZnO is a glass component that improves the thermal stability of glass. However, excessive ZnO content may lead to an increase in specific gravity and a decrease in the relative partial dispersion (PC,t) in the infrared wavelength region. Therefore, from the viewpoint of improving the thermal stability of glass and maintaining the desired optical constants, the ZnO content is preferably within the range described above.

[0170] In the optical glass of the first-1 embodiment, the upper limit of the total content of MgO, CaO, SrO, and BaO [MgO+CaO+SrO+BaO] is preferably 40%, and more preferably in the order of 35%, 30%, 25%, 20%, 15%, and 12%. The lower limit of this total content is preferably 0%, and more preferably in the order of 2%, 4%, 6%, 8%, and 10%. The total content of MgO, CaO, SrO, and BaO [MgO+CaO+SrO+BaO] can be 0%. When this total content is too high, the high dispersion is impaired, and there is a risk of a decrease in the relative partial dispersion PC,t in the infrared wavelength region. In addition, when this total content is too low, the refractive index nd decreases, and there is a risk of a decrease in the thermal stability and devitrification resistance of the glass. Therefore, the total content is preferably within the above range.

[0171] In the optical glass of the first-1 embodiment, the upper limit of the total content R'O [MgO+CaO+SrO+BaO+ZnO] of MgO, CaO, SrO, BaO, and ZnO is preferably 40%, and more preferably in the order of 35%, 30%, 25%, 20%, 15%, and 12%. The lower limit of the total content R'O is preferably 0%, and more preferably in the order of 2%, 4%, 6%, 8%, and 10%. R'O can be 0%. When R'O is too high, high dispersion is impaired, and there is a risk of a decrease in the relative partial dispersion PC,t in the infrared wavelength region. In addition, when R'O is too low, the refractive index nd decreases, and there is a risk of a decrease in the thermal stability and devitrification resistance of the glass. Therefore, R'O is preferably within the above range.

[0172] In the glass of Embodiment 1-1, the upper limit of the Y2O3 content is preferably 30%, and more preferably in the order of 25%, 20%, 15%, 10%, and 5%. Furthermore, the lower limit of the Y2O3 content is preferably 0%, and more preferably in the order of 0.5%, 1.0%, and 1.5%. The Y2O3 content may also be 0%.

[0173] Introducing a certain amount of Y₂O₃ can increase the refractive index (nd). However, excessive Y₂O₃ content reduces the thermal stability of the glass, making it more prone to devitrification during manufacturing. Furthermore, it poses a risk of impaired high dispersion. Therefore, from the viewpoint of suppressing the decrease in the thermal stability of the glass, the Y₂O₃ content is preferably within the range described above.

[0174] In the glass of the first-1 embodiment, the content of Sc2O3 is preferably 2% or less. Furthermore, the lower limit of the Sc2O3 content is preferably 0%.

[0175] In the glass of the first-1 embodiment, the HfO2 content is preferably 2% or less. Furthermore, the lower limit of the HfO2 content is preferably 0%.

[0176] Sc2O3 and HfO2 improve the dispersion of glass, but they are expensive components. Therefore, the contents of Sc2O3 and HfO2 are preferably within the ranges mentioned above.

[0177] In the glass of the first-1 embodiment, the Lu2O3 content is preferably 2% or less. Furthermore, the lower limit of the Lu2O3 content is preferably 0%.

[0178] Lu2O3 improves the dispersion of glass, but due to its large molecular weight, it also increases the specific gravity of the glass. Therefore, the preferred Lu2O3 content is within the range described above.

[0179] In the glass of the first-1 embodiment, the GeO2 content is preferably 2% or less. Furthermore, the lower limit of the GeO2 content is preferably 0%.

[0180] GeO2 improves the dispersion of glass, but it is a very expensive component in commonly used glass compositions. Therefore, from the viewpoint of reducing glass manufacturing costs, the GeO2 content is preferably within the range described above.

[0181] In the optical glass of the first-1 embodiment, the upper limit of the La2O3 content is preferably 30%, and more preferably in the order of 25%, 20%, 15%, 10%, and 5%. Furthermore, the lower limit of the La2O3 content is preferably 0%, and more preferably in the order of 0.5%, 1.0%, and 1.5%. The La2O3 content can also be 0%. By introducing a certain amount of La2O3, the refractive index nd can be increased. However, when the La2O3 content is too high, the thermal stability of the glass decreases, and the glass becomes prone to devitrification during manufacturing. In addition, there is a risk of impaired high dispersion, and a risk of a decrease in the relative partial dispersion PC,t in the infrared wavelength region. Therefore, the La2O3 content is preferably within the above-mentioned range.

[0182] In the glass of the first-1 embodiment, the content of Gd2O3 is preferably 2% or less. Furthermore, the lower limit of the Gd2O3 content is preferably 0%.

[0183] Excessive Gd₂O₃ content reduces the thermal stability of the glass. Furthermore, excessive Gd₂O₃ content increases the specific gravity of the glass, which is undesirable. Moreover, it poses a risk of increased raw material costs. Therefore, from the viewpoint of maintaining good thermal stability of the glass while suppressing an increase in specific gravity, the Gd₂O₃ content preferably falls within the range described above.

[0184] In the glass of the first-1 embodiment, the upper limit of the total content of La2O3, Gd2O3, and Y2O3 [La2O3+Gd2O3+Y2O3] is preferably 30%, and more preferably in the order of 25%, 20%, 15%, 10%, 5%, 3%, and 1%. The lower limit of this total content is preferably 0%. From the viewpoint of suppressing the decrease in the thermal stability of the glass and preventing the decrease in the relative partial dispersion PC,t in the infrared wavelength region, it is preferable that the total content is within the above-mentioned range.

[0185] In the glass of the first-1 embodiment, the content of Yb₂O₃ is preferably 2% or less. Furthermore, the lower limit of the Yb₂O₃ content is preferably 0%.

[0186] Compared to La₂O₃, Gd₂O₃, and Y₂O₃, Yb₂O₃ has a larger molecular weight, thus increasing the specific gravity of the glass. Furthermore, excessive Yb₂O₃ content reduces the thermal stability of the glass. From the viewpoint of preventing a decrease in the thermal stability of the glass and suppressing an increase in specific gravity, the Yb₂O₃ content is preferably within the range described above.

[0187] In the glass of Embodiment 1-1, the upper limit of the mass ratio of the total content of Li2O, Na2O, and K2O (R2O) to the total content of SiO2 and B2O3 [R2O / (SiO2+B2O3)] is preferably 0.50, and more preferably in the order of 0.45, 0.40, 0.35, 0.30, and 0.25. The lower limit of this mass ratio is preferably 0.05, and more preferably in the order of 0.07, 0.09, and 0.11. From the viewpoint of improving the relative partial dispersion (PC,t) in the infrared wavelength region and improving chemical durability, it is preferable that this mass ratio is within the above-mentioned range.

[0188] In the glass of Embodiment 1-1, the upper limit of the mass ratio of the total content of MgO, CaO, SrO, and BaO to the total content of SiO2 and B2O3 [(MgO+CaO+SrO+BaO) / (SiO2+B2O3)] is preferably 0.50, and more preferably in the order of 0.40, 0.35, 0.30, and 0.25. The lower limit of this mass ratio is preferably 0, and more preferably in the order of 0.05, 0.10, and 0.15. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and improving chemical durability, it is preferable that this mass ratio is within the above-mentioned range.

[0189] In the glass of Embodiment 1-1, the upper limit of the mass ratio of the total content R'O of MgO, CaO, SrO, BaO, and ZnO to the total content of SiO2 and B2O3 [R'O / (SiO2+B2O3)] is preferably 0.50, and more preferably in the order of 0.40, 0.35, 0.30, and 0.25. The lower limit of this mass ratio is preferably 0, and more preferably in the order of 0.05, 0.10, and 0.15. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and improving chemical durability, it is preferable that this mass ratio is within the above-mentioned range.

[0190] In the glass of Embodiment 1-1, the upper limit of 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 preferably 0.50, and more preferably in the order of 0.40, 0.35, 0.30, and 0.25. The lower limit of this mass ratio is preferably 0, and more preferably in the order of 0.05, 0.10, and 0.15. The mass ratio may also be 0. From the viewpoint of suppressing the decrease in the thermal stability of the glass, it is preferable that the mass ratio is within the above-mentioned range.

[0191] In the glass of Embodiment 1-1, the upper limit of the mass ratio of the total content of Nb₂O₅, TiO₂, WO₃, and Ta₂O₅ to the total content of SiO₂ and B₂O₃ [(Nb₂O₅+TiO₂+WO₃+Ta₂O₅) / (SiO₂+B₂O₃)] is preferably 0.70, and more preferably in the order of 0.65, 0.60, 0.55, 0.50, 0.45, 0.40, 0.35, 0.30, and 0.25. The lower limit of this mass ratio is preferably 0.05, and more preferably in the order of 0.10, 0.14, 0.16, 0.18, and 0.20. From the viewpoint of maintaining a high refractive index, it is preferable that this mass ratio is within the above-mentioned range.

[0192] In the glass of Embodiment 1-1, the upper limit of the mass ratio of the total content of MgO, CaO, SrO, and BaO to the total content of Li2O, Na2O, and K2O [(MgO+CaO+SrO+BaO) / R2O] is preferably 5, and more preferably in the order of 4.0, 3.0, 2.5, 2.0, 1.8, and 1.6. The lower limit of this mass ratio is preferably 0, and more preferably in the order of 0.20, 0.40, 0.60, 0.80, 1.00, 1.20, and 1.40. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and reducing the viscosity of the molten glass to improve formability, it is preferable that the mass ratio is within the above range.

[0193] In the glass of Embodiment 1-1, the upper limit of the mass ratio [R'O / R2O] of the total content R'O of MgO, CaO, SrO, BaO, and ZnO to the total content R2O of Li2O, Na2O, and K2O is preferably 5, and more preferably in the order of 4.0, 3.0, 2.5, 2.0, 1.8, and 1.6. The lower limit of this mass ratio is preferably 0, and more preferably in the order of 0.20, 0.40, 0.60, 0.80, 1.00, 1.20, and 1.40. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and reducing the viscosity of the molten glass to improve formability, it is preferable that the mass ratio is within the above range.

[0194] In the glass of Embodiment 1-1, the upper limit of the mass ratio of the total content of La2O3, Gd2O3, and Y2O3 to the total content of Li2O, Na2O, and K2O [(La2O3+Gd2O3+Y2O3) / R2O] is preferably 3.0, and more preferably in the order of 2.0, 1.0, 0.8, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.1. The lower limit of this mass ratio is preferably 0, and more preferably in the order of 0.01, 0.05, and 0.08. This mass ratio may also be 0. From the viewpoint of suppressing the decrease in the thermal stability of the glass, it is preferable that this mass ratio is within the above-mentioned range.

[0195] In the glass of Embodiment 1-1, the upper limit of the mass ratio of the total content of Nb₂O₅, TiO₂, WO₃, and Ta₂O₅ to the total content of Li₂O, Na₂O, and K₂O [(Nb₂O₅+TiO₂+WO₃+Ta₂O₅) / R₂O] is preferably 5.0, and more preferably in the order of 4.0, 3.5, 3.0, 2.8, 2.6, 2.4, 2.2, 2.0, and 1.8. The lower limit of this mass ratio is preferably 0.3, and more preferably in the order of 0.5, 0.7, 0.9, 1.1, 1.3, 1.5, and 1.7. From the viewpoint of maintaining a high refractive index, improving the solubility of the glass, and reducing the viscosity of the molten glass to improve formability, it is preferable that the mass ratio is within the above-mentioned range.

[0196] In the glass of the first-1 embodiment, the upper limit of the mass ratio of the total content of Li2O, Na2O, and K2O (R2O) to the total content of R2O, MgO, CaO, SrO, and BaO [R2O / (R2O+MgO+CaO+SrO+BaO)] is preferably 1, and more preferably in the order of 0.9, 0.8, 0.7, 0.6, 0.5, and 0.45. The lower limit of this mass ratio is preferably 0.10, and more preferably in the order of 0.15, 0.20, 0.25, 0.30, and 0.35. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and improving the formability by reducing the viscosity of the molten glass, it is preferable to make this mass ratio within the above range.

[0197] In the glass of the first-1 embodiment, the upper limit of the mass ratio of the total content of Li2O, Na2O, and K2O (R2O), the total content of MgO, and CaO, and the total content of R2O and the total content of MgO, CaO, SrO, BaO, and ZnO (R'O) [(R2O+MgO+CaO) / (R2O+R'O)] is preferably 1, and more preferably in the order of 0.9, 0.8, 0.7, 0.6, 0.5, and 0.45. The lower limit of this mass ratio is preferably 0.10, and more preferably in the order of 0.15, 0.20, 0.25, 0.30, and 0.35. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and improving the formability by reducing the viscosity of the molten glass, it is preferable to make this mass ratio within the above range.

[0198] In the glass of Embodiment 1-1, the upper limit of the mass ratio of the total content of La2O3, Gd2O3, and Y2O3 to the total content of Nb2O5, TiO2, WO3, and Ta2O5 [(La2O3+Gd2O3+Y2O3) / (Nb2O5+TiO2+WO3+Ta2O5)] is preferably 1, and more preferably in the order of 0.8, 0.6, 0.4, and 0.2. The lower limit of this mass ratio is preferably 0, and more preferably in the order of 0.05, 0.10, and 0.15. This mass ratio may also be 0. From the viewpoint of suppressing the decrease in the thermal stability of the glass and maintaining a high refractive index, it is preferable that this mass ratio is within the above-mentioned range.

[0199] The glass of the preferred embodiment 1-1 is mainly composed of the glass components described above, namely, SiO2, B2O3, ZrO2, and Nb2O5 as essential components, and P2O5, Al2O3, Li2O, Na2O, K2O, Cs2O, TiO2, WO3, Bi2O3, Ta2O5, MgO, CaO, SrO, BaO, ZnO, Y2O3, Sc2O3, HfO2, Lu2O3, GeO2, La2O3, Gd2O3, and Yb2O3 as optional components. The total content of the above-mentioned glass components is preferably 95% or more, more preferably 98% or more, further preferably 99% or more, and particularly preferably 99.5% or more.

[0200] It should be noted that the glass in the first-1 embodiment is preferably composed of the glass components described above, but may contain other components to the extent that it does not impair the effects of the present invention. Furthermore, the presence of unavoidable impurities is not excluded in the present invention.

[0201] In addition to the above-mentioned components, the optical glass may also contain a small amount of Sb2O3 or the like as a clarifying agent. The total amount of clarifying agent (additional amount) is preferably 0% or more and less than 1%, more preferably 0% or more and less than 0.5%.

[0202] Additional addition refers to the amount of clarifying agent added, expressed as a weight percentage, when the total content of all glass components other than the clarifying agent is set to 100%.

[0203] Furthermore, the aforementioned optical glass can achieve high transmittance across a wide range of the visible light spectrum. To fully utilize this advantage, it is preferable to avoid containing coloring elements. Examples of coloring elements include Cu, Co, Ni, Fe, Cr, Eu, Nd, Er, V, and Ag. Preferably, all elements are below 100 ppm by mass, more preferably 0 to 80 ppm by mass, even more preferably 0 to 50 ppm by mass, and particularly preferably substantially absent.

[0204] Ga, Te, Tb, etc. are components that do not need to be introduced and are also expensive components. Therefore, the content of Ga2O3, TeO2, and TbO2, expressed in mass %, is preferably 0 to 0.1%, more preferably 0 to 0.05%, further preferably 0 to 0.01%, even more preferably 0 to 0.005%, even more preferably 0 to 0.001%, and particularly preferably substantially not contained.

[0205] (Glass properties)

[0206] <Abbe number νd>

[0207] In the optical glass of the first-1 embodiment, the Abbe number νd is preferably 30 to 60, but can also be set to 35 to 55, 40 to 50, 41 to 48, 42 to 46, 43 to 45, or 32 to 50, 34 to 45, 36 to 40, or 37 to 39.

[0208] The Abbe number νd can be set to a desired value by appropriately adjusting the content of each glass component. This will relatively reduce the Abbe number νd of the components, i.e., the high dispersion components are Nb₂O₅, TiO₂, ZrO₂, WO₃, Bi₂O₃, and Ta₂O₅ (expressed as Nb cations). 5+ Ti 4+ Zr 4+ W 6+ Bi 3+ Ta 5+ On the other hand, it will relatively increase the components with the Abbe number νd, that is, the low dispersion components are SiO2, B2O3, Li2O, Na2O, K2O, La2O3, BaO, CaO, SrO (expressed as Si cations). 4+ B 3+ Li + Na + K + La 3+ Ba 2+ Ca 2+ 、Sr 2+ )wait.

[0209] In this invention, the Abbe number νd, the relative partial dispersion PC,t (described later), and the relative partial dispersion Pg,F are calculated as follows: Specifically, the refractive indices at the 12 wavelengths shown in Table A are measured using Japanese Industrial Standard (JIS) B 7071-1, Method for Determining the Refractive Index of Optical Glass - Part 1: Method of Minimum Deflection Angle. Next, the refractive indices of each spectral line obtained by measurement are substituted into the Schott dispersion formula specified in Annex B of JIS B 7071-1, Method for Determining the Refractive Index of Optical Glass - Part 1: Method of Minimum Deflection Angle, and the constants of the Schott dispersion formula are obtained using the least squares method. Then, using the Schott dispersion formula with determined constants, the Abbe number νd, the relative partial dispersion PC,t (described later), and the relative partial dispersion Pg,F are calculated based on the obtained refractive index values ​​for each spectral line.

[0210] [Table A]

[0211] Wavelength (nm) Spectral lines light source 1013.98 T-rays (infrared mercury) Hg 852.11 G-rays (infrared cesium) Cs 706.52 gamma rays (red helium) He 656.27 C-rays (red hydrogen) H 643.85 C' rays (red cadmium) Cd 587.56 D-rays (yellow helium) He 546.07 gamma rays (green mercury) Hg 486.13 F-rays (blue hydrogen) H 479.99 F' rays (blue cadmium) Cd 435.84 Gamma rays (blue mercury) Hg 404.66 h-rays (purple mercury) Hg 365.01 i-rays (ultraviolet mercury) Hg

[0212] Schott dispersion formula: n 2 =a0+a1λ 2 +a2λ -2 +a3λ -4 +a4λ-6 +a5λ -8

[0213] In the formula, n is the refractive index, λ is the wavelength (μm), and a0, a1, a2, a3, a4, and a5 are constants.

[0214] The Abbe number νd is represented using the refractive indices nd, nF, and nC under d-rays, F-rays, and C-rays as shown below.

[0215] νd=(nd-1) / (nF-nC)

[0216] <Refractive index nd>

[0217] In the optical glass of the first-1 embodiment, the refractive index nd is preferably 1.50 to 1.80, but may also be 1.55 to 1.70, 1.58 to 1.65, 1.60 to 1.62, or 1.60 to 1.70, 1.63 to 1.69, or 1.66 to 1.68.

[0218] The refractive index nd can be set to a desired value by appropriately adjusting the content of each glass component. Components that relatively increase the refractive index nd (high refractive index components) are Nb₂O₅, TiO₂, ZrO₂, Ta₂O₅, and La₂O₃ (expressed as Nb cations). 5+ Ti 4+ Zr 4+ Ta 5+ La 3+ On the other hand, components that have the effect of relatively reducing the refractive index (nd) (lower refractive index components) are SiO2, B2O3, Li2O, Na2O, and K2O (expressed as cations Si). 4+ B 3+ Li + Na + K + )wait.

[0219] <Relative Partial Dispersion PC,t>

[0220] In the optical glass of the first-1 embodiment, the lower limit of the relative partial dispersion PC,t in the infrared wavelength region is preferably 0.7300, and more preferably in the order of 0.7400, 0.7500, 0.7600, 0.7700, 0.7750, 0.7800, 0.7850, 0.7860, 0.7870, 0.7880, 0.7890, 0.7900, 0.7910, 0.7920, 0.7930, 0.7940, and 0.7950. By making the relative partial dispersion PC,t within the above range, optical glass suitable for compensating for higher-order chromatic aberrations can be obtained. On the other hand, the upper limit of the relative partial dispersion PC,t is not particularly limited, and is generally 0.9000, preferably 0.8700, and more preferably in the order of 0.8500 and 0.8400.

[0221] In addition, in the optical glass of the first-1 embodiment, the relative partial dispersion PC,t preferably satisfies the following formula [1].

[0222] PC,t≥0.5711+0.004667×νd···[1]

[0223] The relative partial dispersion Pg,F more preferably satisfies the following equation [2], and even more preferably satisfies it in the order of the following equations [3], [4], [5], [6], and [7].

[0224] PC,t≥0.5731+0.004667×νd···[2]

[0225] PC,t≥0.5751+0.004667×νd···[3]

[0226] PC,t≥0.5771+0.004667×νd···[4]

[0227] PC,t≥0.5791+0.004667×νd···[5]

[0228] PC,t≥0.5811+0.004667×νd···[6]

[0229] PC,t≥0.5831+0.004667×νd···[7]

[0230] By making the relative partial dispersion PC,t satisfy the above formula, the optical element made of the optical glass of the first-1 embodiment can well compensate for chromatic aberration over a wide wavelength range.

[0231] In the optical glass of the first-1 embodiment, the lower limit of the deviation ΔPC,t is preferably 0.0250, and more preferably in the order of 0.0270, 0.0290, 0.0310, 0.0330, 0.0350, and 0.0370. By making the deviation ΔPC,t within the above range, optical glass suitable for compensating for higher-order chromatic aberrations can be obtained. On the other hand, the upper limit of the deviation ΔPC,t is not particularly limited, and is generally 0.0900, preferably 0.0800.

[0232] The relative partial dispersion PC,t is calculated using the Schott dispersion formula described above.

[0233] The relative partial dispersion PC,t is represented by the refractive indices nt, nF, and nC under t-rays, F-rays, and C-rays as shown below.

[0234] PC,t = (nC - nt) / (nF - nC)

[0235] Furthermore, in a plane where the Abbe number νd is represented by the horizontal axis and the relative partial dispersion PC,t is represented by the vertical axis, the normal is expressed by the following formula.

[0236] PC,t(0)=0.5461-(0.004667×νd)

[0237] Furthermore, the deviation ΔPC,t of the relative partial dispersion PC,t with respect to the normal is expressed as follows.

[0238] ΔPC,t=PC,t-PC,t(0)

[0239] The relative partial dispersion PC,t can be set to the desired value by appropriately adjusting the content of each glass component. The components that have the effect of relatively improving the relative partial dispersion PC,t are SiO2, B2O3, Al2O3, and Li2O (expressed as Si cations). 4+ B 3+ Al 3+ Li + On the other hand, the components that have the effect of relatively reducing the relative partial dispersion PC,t are SrO, BaO, ZnO, La2O3, TiO2, Nb2O5, and WO3 (expressed as cations Sr, BaO, ZnO, La2O3, TiO2, Nb2O5, and WO3). 2+ Ba 2+ Zn 2+ La 3+ Ti 4+ 、Nb 5+ W 6+ ), etc. In this embodiment, particularly through <1> In a large quantity of SiO2 and B2O3 (represented as Si cations) which are components that increase PC,t, 4+ and B 3+At the same time, <2> Appropriately add SiO2 (Si 4+ A portion of ) was replaced with B2O3 (B 3+ Achieving high dispersion without significantly reducing PC,t <3> With the aim of further improving formability through high dispersion and low viscosity, alkali metal and alkaline earth metal oxides are appropriately introduced. <4> To minimize the amount of highly dispersible components required to obtain the desired Abbe number and which also reduce PC,t, Nb₂O₅ (Nb) is actively introduced, particularly among the highly dispersible components, to relatively suppress the reduction of PC,t. 5+ ), and ZrO2 (Zr2O3), which can simultaneously achieve the reduction and suppression of PC,t and the chemical durability of glass. 4+ This allows for the production of optical glass with a small Abbe number νd and a relatively high partial dispersion PC,t.

[0240] <Relative partial dispersion Pg,F>

[0241] In the optical glass of the first-1 embodiment, the upper limit of the relative partial dispersion Pg,F in the visible short wavelength region is preferably 0.5800, and more preferably in the order of 0.5750, 0.5720, 0.5690, 0.5660, 0.5640, 0.5630, 0.5620, 0.5610, and 0.5600. By making the relative partial dispersion Pg,F within the above range, an optical glass suitable for compensating for higher-order chromatic aberrations can be obtained. On the other hand, the lower limit of the relative partial dispersion Pg,F is not particularly limited, and is generally 0.5500, preferably 0.5550.

[0242] In addition, in the optical glass of the first-1 embodiment, the relative partial dispersion Pg,F preferably satisfies the following formula [8].

[0243] Pg,F≤0.6483-0.001802×νd···[8]

[0244] The relative partial dispersion Pg,F more preferably satisfies the following formula [9], and even more preferably satisfies it in the order of the following formulas

[10] ,

[11] ,

[12] ,

[13] , and

[14] .

[0245] Pg,F≤0.6470-0.001802×νd···[9]

[0246] Pg,F≤0.6460-0.001802×νd···

[10]

[0247] Pg,F≤0.6450-0.001802×νd···

[11]

[0248] Pg,F≤0.6444-0.001802×νd···

[12]

[0249] Pg,F≤0.6439-0.001802×νd···

[13]

[0250] Pg,F≤0.6433-0.001802×νd···

[14]

[0251] By making the relative partial dispersion Pg,F satisfy the above formula, the optical element made of the optical glass of the first-1 embodiment can well compensate for chromatic aberration over a wide wavelength range.

[0252] In the optical glass of the first-1 embodiment, the upper limit of the deviation ΔPg,F is preferably 0, and more preferably in the order of -0.0013, -0.0023, -0.0033, -0.0039, -0.0044, and -0.0050. By making the deviation ΔPg,F within the above range, optical glass suitable for compensating for higher-order chromatic aberrations can be obtained. On the other hand, the lower limit of the deviation ΔPg,F is not particularly limited, and is generally -0.0300, preferably -0.0250.

[0253] The relative partial dispersion Pg,F is calculated using the Schott dispersion formula described above.

[0254] The relative partial dispersion Pg,F is represented by the refractive indices ng, nF, and nC under g-rays, F-rays, and C-rays as shown below.

[0255] Pg,F=(ng-nF) / (nF-nC)

[0256] Furthermore, in a plane where the Abbe number νd is represented by the horizontal axis and the relative partial dispersion Pg,F is represented by the vertical axis, the normal is expressed by the following formula.

[0257] Pg,F(0)=0.6483-(0.001802×νd)

[0258] Furthermore, the deviation ΔPg,F of the relative partial dispersion Pg,F with respect to the normal is expressed as follows.

[0259] ΔPg,F=Pg,F-Pg,F(0)

[0260] <Specific gravity of glass>

[0261] The specific gravity of the optical glass in the first-1 embodiment is preferably 4.00 or less, more preferably 3.50 or less, and even more preferably 3.10 or less.

[0262] The components that will relatively increase the specific gravity are BaO, La2O3, ZrO2, Nb2O5, and Ta2O5 (expressed as cations Ba).2+ La 3+ Zr 4+ 、Nb 5+ Ta 5+ On the other hand, components that relatively reduce the specific gravity include SiO2, B2O3, Li2O, Na2O, and K2O (expressed as cations Si). 4+ B 3+ Li + Na + K + (etc.) By appropriately adjusting the content of these components, the specific gravity can be controlled.

[0263] <Liquid phase temperature LT>

[0264] The upper limit of the liquidus temperature LT of the optical glass in the first-1 embodiment is preferably 1300°C, and more preferably in the order of 1270°C, 1240°C, 1210°C, 1180°C, 1150°C, and 1100°C. By setting the liquidus temperature within the above range, the melting and forming temperature of the glass can be reduced. As a result, the generation of ripples caused by erosion of glass melting equipment (e.g., crucible, stirring equipment for molten glass, etc.) during the melting process and the volatilization of the glass components themselves can be reduced. The lower limit of the liquidus temperature LT is not particularly limited, and is generally 1000°C, preferably 1050°C. The liquidus temperature LT is determined by the balance of the contents of all glass components. Among them, SiO2, B2O3, Li2O, Na2O, and K2O (represented as Si cations) are... 4+ B 3+ Li + Na + K + The content of ZrO2 and Al2O3 (expressed as Zr cations) has a significant impact on the liquidus temperature (LT). 4+ Al 3+ When the content of substances such as ) is high, the liquid phase temperature rises.

[0265] The liquidus temperature is determined as follows: 10 cc (10 ml) of glass is placed in a platinum crucible and melted at 1250°C–1400°C for 15–30 minutes. After cooling to below the glass transition temperature Tg, the glass, along with the platinum crucible, is placed in a melting furnace at a given temperature and held for 2 hours. Temperatures above 1000°C are marked with increments of 5°C or 10°C. After holding for 2 hours, the glass is cooled, and the presence or absence of crystallization within the glass is observed using a 100x optical microscope. The lowest temperature at which no crystals have precipitated is taken as the liquidus temperature.

[0266] <Glass transition temperature Tg>

[0267] The lower limit of the glass transition temperature Tg of the optical glass in the first-1 embodiment is preferably 400°C, and more preferably in the order of 450°C, 470°C, and 490°C. Furthermore, the upper limit of the glass transition temperature Tg is preferably 600°C, and more preferably in the order of 580°C, 560°C, and 550°C.

[0268] The components that relatively lower the glass transition temperature Tg are Li₂O, Na₂O, and K₂O (expressed as cations Li). + Na + K + The components that relatively increase the glass transition temperature (Tg) are La₂O₃, ZrO₂, and Nb₂O₅ (expressed as La cations). 3+ Zr 4+ 、Nb 5+ (e.g.) By appropriately adjusting the content of these components, the glass transition temperature Tg can be controlled.

[0269] <Light Transmittance of Glass>

[0270] The light transmittance of the optical glass in Embodiment 1-1 can be evaluated based on tinting degrees λ80 and λ5.

[0271] For glass samples with a thickness of 10.0 mm ± 0.1 mm, the spectral transmittance was measured in the wavelength range of 200 to 700 nm. The wavelength at which the external transmittance reaches 80% was set as λ80, and the wavelength at which the external transmittance reaches 5% was set as λ5.

[0272] In the first embodiment, the λ80 of the optical glass is preferably 450 nm or less, more preferably 430 nm or less, and even more preferably 410 nm or less. The λ5 is preferably 400 nm or less, more preferably 380 nm or less, and even more preferably 360 nm or less.

[0273] <Chemical durability and water resistance Dw>

[0274] In the optical glass of the first-1 embodiment, the water resistance Dw is preferably level 5 or above, more preferably level 4 or above, and even more preferably level 3 or above.

[0275] A mass of powdered glass (particle size 425–600 μm) of equivalent specific gravity was placed in a platinum cage and immersed in a quartz glass round-bottom flask containing 80 mL of pure water (pH = 6.5–7.5). The mixture was then treated in a boiling water bath for 60 minutes. The water resistance Dw was evaluated by classifying the powdered glass according to the weight reduction rate (%) in Table B.

[0276] [Table B]

[0277] grade Quality reduction (%) 1 Less than 0.05% 2 Above 0.05% and below 0.10% 3 Above 0.10% and below 0.25% 4 Above 0.25% and below 0.60% 5 Above 0.60% and less than 1.10% 6 1.10% or more

[0278] <Chemical durability and acid resistance (Da)>

[0279] In the optical glass of the first-1 embodiment, the acid resistance Da is preferably level 5 or above, more preferably level 4 or above, and even more preferably level 3 or above.

[0280] A mass of powdered glass (particle size 425–600 μm) of equivalent specific gravity was placed in a platinum cage and immersed in a quartz glass round-bottom flask containing 80 mL of 0.01 mol / L nitric acid aqueous solution for 60 minutes. The acid resistance (Da) was evaluated by classifying the powdered glass according to the grade in Table C based on the mass reduction rate (%).

[0281] [Table C]

[0282] grade Quality reduction (%) 1 Less than 0.20% 2 Above 0.20% and below 0.35% 3 Above 0.35% and below 0.65% 4 Above 0.65% and less than 1.20% 5 1.20% or more but less than 2.20% 6 2.20% or more

[0283] Chemical durability and resistance to latent damage (D) N a OH >

[0284] In the optical glass of the first-1 embodiment, the resistance to latent damage D NaOH Preferably, it is level 4 or above, more preferably level 3 or above, and even more preferably level 2 or above.

[0285] A diameter of 43.7mm (30cm on both sides) 2 A glass sample, approximately 5 mm thick and polished on both sides, was immersed in a 0.01 mol / L NaOH aqueous solution at 50°C for 15 hours after thorough stirring. At this time, the mass reduction per unit area [mg / (cm²)] was calculated. 2 [15h] Classified according to the level in Table D, the resistance to lurking damage D NaOH To conduct an evaluation.

[0286] [Table D]

[0287] grade <![CDATA[Mass reduction [mg / (cm 2 ·15 h)]]]> 1 Less than 0.02 2 Above 0.02 and below 0.10 3 0.10 or higher and less than 0.20 4 Above 0.20 and below 0.30 5 0.30 and above

[0288] Chemical durability and resistance to latent damage (D) STPP >

[0289] In the optical glass of the first-1 embodiment, the resistance to latent damage D STPP Preferably, it is level 4 or above, more preferably level 3 or above, and even more preferably level 2 or above.

[0290] A diameter of 43.7mm (30cm on both sides) 2 A glass sample, approximately 5 mm thick and polished on both sides, was thoroughly stirred at 50°C in 0.01 mol / L Na₅P₃O₂ solution. 10After immersion in (STPP) aqueous solution for 1 hour, the mass reduction per unit area is calculated as [mg / (cm²)]. 2 According to the classification in Table E, the resistance to lurking damage D is classified. STPP To conduct an evaluation.

[0291] [Table E]

[0292] grade <![CDATA[Mass reduction [mg / (cm 2 ·h)] <!-- 19 -->]]> 1 Less than 0.02 2 Above 0.02 and below 0.20 3 Above 0.20 and below 0.40 4 Above 0.40 and below 0.60 5 0.60 and above

[0293] <Chemical durability D0>

[0294] In the optical glass of the first-1 embodiment, the chemical durability D0 is preferably level 4 or above, more preferably level 3 or above, and even more preferably level 2 or above.

[0295] A diameter of 43.7mm (30cm on both sides) 2 A glass sample, approximately 5 mm thick and polished on both sides, was immersed in pure water at 50°C, pH 7.0 ± 0.2, and thoroughly stirred while passing through and circulating in an ion exchange resin layer at a rate of 1 L / min. The mass reduction per unit area was

[10] -3 mg / (cm 2 The chemical durability D0 is evaluated according to the classification in Table F.

[0296] [Table F]

[0297] grade <![CDATA[Mass reduction [10 -3 mg / (cm 2 ·h)]]]> 1 Less than 0.4 2 0.4 or higher and less than 5.0 3 5.0 or higher but less than 10.0 4 10.0 or higher but less than 15.0 5 15.0 or above

[0298] (Manufacturing of optical glass)

[0299] The glass of Embodiment 1-1 is prepared by mixing glass raw materials to achieve the given composition described above, and then manufactured using the prepared glass raw materials according to known glass manufacturing methods. For example, multiple compounds are mixed thoroughly to prepare a batch of raw materials, which are then placed in a quartz crucible or a platinum crucible for rough melting. The molten material obtained from rough melting is quenched and pulverized to produce crushed glass. The crushed glass is further placed in a platinum crucible for heating and remelting to produce molten glass. After further clarification and homogenization, the molten glass is shaped and slowly cooled to obtain optical glass. The shaping and slow cooling of the molten glass can be performed using known methods.

[0300] It should be noted that as long as the desired glass composition can be introduced into the glass and the desired content can be achieved, there are no particular restrictions on the compounds used when preparing batch raw materials. Examples of such compounds include oxides, carbonates, nitrates, hydroxides, and fluorides.

[0301] (Manufacturing of optical components, etc.)

[0302] When manufacturing optical elements using the optical glass of Embodiment 1-1, known methods can be employed. For example, in the manufacturing of the aforementioned optical glass, molten glass is poured into a mold to form a plate, thus producing a glass raw material formed from the optical glass of the present invention. The obtained glass raw material is appropriately cut, ground, and polished to produce fragments of a size and shape suitable for pressing. The fragments are heated and softened, and then pressed (re-hot-pressed) using a known method to produce an optical element blank with a shape approximating that of an optical element. The optical element blank is annealed, and then ground and polished using a known method to manufacture the optical element.

[0303] Depending on the intended use, anti-reflective films, total reflection films, etc., can be applied to the optical functional areas of the manufactured optical components.

[0304] According to one aspect of the present invention, an optical element made of the aforementioned optical glass can be provided. Examples of optical elements include spherical lenses, aspherical lenses, lenses, prisms, diffraction gratings, etc. Examples of lens shapes include biconvex lenses, plano-convex lenses, biconcave lenses, plano-concave lenses, convex meniscus lenses, concave meniscus lenses, and various other shapes. The optical element can be manufactured by a method including processing a glass molded body made of the aforementioned optical glass. Examples of processing include cutting, shaving, rough grinding, fine grinding, polishing, etc. During such processing, by using the aforementioned glass, breakage can be reduced, and high-quality optical elements can be supplied reliably.

[0305] Implementation Method 1-2

[0306] In the optical glass of embodiments 1-2,

[0307] As a component of glass

[0308] Contains SiO2, B2O3, ZrO2 and Nb2O5.

[0309] It contains one or more selected from Li₂O, Na₂O, and K₂O.

[0310] The ΔPC,t of the optical glass is 0.0250 or higher.

[0311] The optical glass of embodiments 1-2 contains SiO2 as a glass component. The lower limit of the SiO2 content is preferably 20%, and more preferably in the order of 24%, 26%, and 28%. Furthermore, the upper limit of the SiO2 content is preferably 50%, and more preferably in the order of 45%, 40%, and 35%. SiO2 is a network-forming component of the glass. By containing SiO2 as a glass component, the relative partial dispersion (PC,t) in the infrared wavelength region can be increased, thereby improving chemical durability. From the viewpoint of suppressing the decrease in the relative partial dispersion (PC,t) in the infrared wavelength region and suppressing the decrease in the thermal stability and chemical durability of the glass, the lower limit of the SiO2 content is preferably set as described above. From the viewpoint of suppressing the decrease in the solubility of the glass and preventing the increase in the viscosity of the molten glass from deteriorating its formability, the upper limit of the SiO2 content is preferably set as described above.

[0312] The optical glass of embodiments 1-2 contains B2O3 as a glass component. The lower limit of the B2O3 content is preferably 15%, and more preferably in the order of 17%, 19%, and 21%. Furthermore, the upper limit of the B2O3 content is preferably 50%, and more preferably in the order of 45%, 40%, and 35%. B2O3 is a network-forming component of the glass. By containing B2O3 as a glass component, the relative partial dispersion (PC,t) in the infrared wavelength region can be improved. From the viewpoint of suppressing the decrease in the relative partial dispersion (PC,t) in the infrared wavelength region and suppressing the decrease in the thermal stability of the glass, the lower limit of the B2O3 content is preferably set as described above. From the viewpoint of suppressing the decrease in the chemical durability of the glass, the upper limit of the B2O3 content is preferably set as described above.

[0313] The optical glass of embodiments 1 and 2 contains ZrO2 as a glass component. The lower limit of the ZrO2 content is preferably 5.0%, and more preferably in the order of 6.5%, 8.0%, and 9.5%. Furthermore, the upper limit of the ZrO2 content is preferably 30%, and more preferably in the order of 25%, 20%, and 15%. By containing ZrO2 as a glass component, the relative partial dispersion PC,t in the infrared wavelength region can be improved, thereby improving chemical durability. From the viewpoint of suppressing the decrease in chemical durability, the lower limit of the ZrO2 content is preferably set as described above. From the viewpoint of suppressing the rise in liquidus temperature LT and suppressing the decrease in stability upon reheating, the upper limit of the ZrO2 content is preferably set as described above.

[0314] The optical glass of embodiments 1 and 2 contains Nb₂O₅ as a glass component. The content of Nb₂O₅ is preferably more than 5.0%, and its lower limit is more preferably in the order of 6.5%, 8.0%, and 9.5%. Furthermore, the upper limit of the Nb₂O₅ content is preferably 30%, and more preferably in the order of 25%, 20%, and 15%. By containing Nb₂O₅ as a glass component, high dispersion can be maintained while suppressing the decrease in relative partial dispersion (PC,t) in the infrared wavelength region. From the viewpoint of maintaining high dispersion, the lower limit of the Nb₂O₅ content is preferably set as described above. From the viewpoint of suppressing the decrease in relative partial dispersion (PC,t) in the infrared wavelength region, the lower limit of the Nb₂O₅ content is preferably set as described above.

[0315] The optical glass of embodiments 1-2 contains one or more selected from Li₂O, Na₂O, and K₂O as a glass component. Preferably, it contains Na₂O; it may contain Li₂O and Na₂O, Na₂O and K₂O, Li₂O and K₂O, or Li₂O, Na₂O, and K₂O. By containing one or more selected from Li₂O, Na₂O, and K₂O as a glass component, the relative partial dispersion PC,t in the infrared wavelength region can be improved, thereby improving chemical durability.

[0316] In the optical glass of embodiments 1 and 2, the upper limit of the mass ratio of the total content of Li2O, Na2O, and K2O (R2O) and the total content of MgO, CaO, SrO, BaO, and ZnO (R'O) to the total content of SiO2 and B2O3 [(R2O+R'O) / (SiO2+B2O3)] is preferably 0.36, and more preferably in the order of 0.35, 0.34, and 0.33. Furthermore, the lower limit of this mass ratio is preferably 0.05, and more preferably in the order of 0.10, 0.15, and 0.20. From the viewpoint of improving the relative partial dispersion (PC,t) in the infrared wavelength region and improving chemical durability, it is preferable that this mass ratio is within the above-mentioned range.

[0317] In the optical glass of the first and second embodiments, the lower limit of the content of B2O3 and the mass ratio of the total content of ZrO2, Nb2O5, TiO2, WO3, Bi2O3 and Ta2O5 [B2O3 / (ZrO2+Nb2O5+TiO2+WO3+Bi2O3+Ta2O5)] is preferably 0.74, and more preferably in the order of 0.84, 0.94 and 1.04. Furthermore, the upper limit of this mass ratio is preferably 3.0, and more preferably in the order of 2.5, 2.0 and 1.5. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, it is preferable that this mass ratio is within the above-mentioned range.

[0318] In the optical glass of the first and second embodiments, the lower limit of the total content of ZrO2, Nb2O5, TiO2, WO3, and Ta2O5 [ZrO2+Nb2O5+TiO2+WO3+Ta2O5] is preferably 22%, and more preferably in the order of 22.5%, 23.0%, and 23.5%. Furthermore, the upper limit of this total content is preferably 40%, and more preferably in the order of 35%, 30%, and 25%. From the viewpoint of increasing the refractive index nd and setting the Abbe number νd to a desired range, it is preferable that the total content is within the above-mentioned range.

[0319] The optical glass of embodiments 1-2 preferably contains substantially no Pb, a component with potential environmental burden. That is, the Pb content is preferably 0% when converted to oxides. Furthermore, As and Th, like Pb, are components with potential environmental burden. Therefore, the content of each of As and Th, when converted to oxides, is preferably 0-0.1%, which can be 0-0.05% or 0-0.01%. The content of each of As and Th, when converted to oxides, is preferably 0%. That is, it is preferable that neither As nor Th is substantially present.

[0320] In the optical glass of the first and second embodiments, the content and ratio of glass components other than those described above can be the same as in the first and first embodiments.

[0321] In the optical glass of the first and second embodiments, the deviation ΔPC,t is 0.0250 or higher. The lower limit of the deviation ΔPC,t is preferably 0.0270, and more preferably in the order of 0.0290, 0.0310, 0.0330, 0.0350, and 0.0370. By making the deviation ΔPC,t within the above range, optical glass suitable for compensating for higher-order chromatic aberrations can be obtained. On the other hand, the upper limit of the deviation ΔPC,t is not particularly limited, and is typically 0.0900, preferably 0.0800. It should be noted that the method for calculating the deviation ΔPC,t is as described in the first embodiment.

[0322] In the optical glass of the first and second embodiments, the glass properties other than those described above may be the same as those of the first and first embodiments.

[0323] The manufacturing of optical glass and optical components in embodiments 1-2 can be the same as in embodiment 1-1.

[0324] Implementation Method 2

[0325] In the second embodiment (the second-1st and second-2nd embodiments), unless otherwise specified, the glass composition of the optical glass is expressed as cation % (cationic percentage). Cationic percentage refers to the molar percentage when the total content of all cationic components is set to 100%. In the second embodiment (the second-1st and second-2nd embodiments), unless otherwise specified, the content and total content of the glass components are based on cation % (cationic percentage), where "%" refers to "cation %". Furthermore, in this specification and the present invention, a content of 0% for a constituent component means that the constituent component is substantially not present, but is permitted to be present at an unavoidable level of impurities.

[0326] It should be noted that the anion % refers to the molar percentage when the total content of all anionic components is set to 100%.

[0327] The valence of the cationic component (e.g., B) 3+ The valence is +3, Si 4+ The price is +4, La 3+ The valence of the cations (+3) is a conventionally determined value, and when B, Si, and La are expressed as glass components on an oxide basis, it is the same as when expressed as B₂O₃, SiO₂, and La₂O₃. Therefore, when analyzing glass composition, the valence of the cations can be omitted. Additionally, the valence of the anions (e.g., O) is also considered. 2- The valence of the anionic component is -2, which is also a conventionally determined value. As mentioned above, the glass composition expressed in oxide terms is the same as that expressed as, for example, B2O3, SiO2, La2O3. Therefore, when analyzing the glass composition, the valence of the anionic component does not need to be analyzed.

[0328] Implementation Method 2-1

[0329] In embodiment 2-1, the glass composition was designed based on the following criteria. That is, <1> In Si containing a large amount of components that increase the relative partial dispersion PC,t in the infrared wavelength region 4+ and B 3+ At the same time, <2> Appropriately Si 4+ Replace part of it with B 3+ Achieving high dispersion without significantly reducing PC,t <3> With the aim of further improving formability through high dispersion and low viscosity, alkali metal and alkaline earth metal oxides are appropriately introduced. <4> To minimize the amount of the highly dispersive component required to obtain the desired Abbe number and which also reduces PC,t, Nb is actively introduced, particularly in the highly dispersive component, to relatively suppress the reduction of PC,t. 5+ And Zr, which can simultaneously reduce PC,t and improve the chemical durability of glass. 4+This resulted in an optical glass with a small Abbe number νd and relatively high partial dispersion PC,t in the infrared wavelength region. The optical glass of the second-1 embodiment is described below.

[0330] In the optical glass of embodiment 2-1,

[0331] Si 4+ The content is above 10%.

[0332] B 3+ The content is over 20%.

[0333] Si 4+ and B 3+ Total content [Si] 4+ +B 3+ The percentage is over 50%.

[0334] B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The value is above 0.44.

[0335] Li + Na + and K + The total content R, and the total content R and Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total cation ratio of the total content R' [R / (R+R')] is 0.55 or higher.

[0336] Nb 5+ The content is greater than 0% and less than 11.5%.

[0337] The optical glass satisfies one or more of the following conditions (i) and (ii).

[0338] (i)Zr 4+ The content of R' and Nb is related to the total content mentioned above. 5+ Ti 4+ W 6+ Bi 3+ and Ta 5+ The total content of cation ratio [Zr 4+ / (R'+Nb 5+ +Ti 4+ +W 6+ +Bi 3+ +Ta 5+ The value is above 0.17.

[0339] (ii)Zr 4+ and Ta 5+ The total content is the same as the total content of R' and Nb mentioned above. 5+ Ti 4+ W 6+ and Bi 3+ The total content of cation ratio [(Zr 4+ +Ta 5+ ) / (R'+Nb 5+ +Ti 4+ +W 6+ +Bi 3+ The value is above 0.25.

[0340] In the optical glass of the second-1 embodiment, Si 4+ The content is above 10%. Si 4+ The lower limit of the Si content is preferably 12%, and more preferably in the order of 14%, 16%, 18%, 20%, 22%, 23%, and 24%. Additionally, Si... 4+ The upper limit of the content is preferably 50%, and more preferably in the order of 43%, 40%, 38%, 36%, 34%, 32%, and 30%. Si 4+ It is a network-forming component of glass. By making Si... 4+ When the content of Si is within the above range, the relative partial dispersion PC,t in the infrared wavelength region can be improved, thereby improving chemical durability. 4+ When the content of Si is too low, the relative partial dispersion PC,t in the infrared wavelength region decreases, and there is a risk of reduced thermal stability and chemical durability of the glass. 4+ Excessive content of certain substances may lead to reduced solubility of the glass, as well as increased viscosity of the molten glass, resulting in poor formability.

[0341] In the optical glass of the second-1 embodiment, B 3+ The content is above 20%. B 3+ The lower limit of the content is preferably 25%, and more preferably in the order of 28%, 29%, 30%, 31%, and 32%. Additionally, B... 3+ The upper limit of its content is preferably 60%, and more preferably in the order of 55%, 50%, 48%, 46%, and 44%. 3+ It is a network-forming component of glass. By making B 3+ When the content of [agent] is within the above range, it can improve the relative partial dispersion PC,t in the infrared wavelength region. 3+ When the content is too low, the relative partial dispersion PC,t in the infrared wavelength region decreases, and there is a risk of reduced thermal stability of the glass. 3+Excessive content of certain substances may reduce the chemical durability of the glass.

[0342] In the optical glass of the second-1 embodiment, Si 4+ and B 3+ Total content [Si] 4+ +B 3+ The content is 50% or more. The lower limit of this total content is preferably 52%, and more preferably in the order of 54%, 56%, and 57%. Furthermore, the upper limit of this total content is preferably 80%, and more preferably in the order of 78%, 76%, 74%, 72%, and 71%. By setting the total content within the above range, the relative partial dispersion (PC,t) in the infrared wavelength region can be improved, thus maintaining the thermal stability of the glass. If the total content is too low, the relative partial dispersion (PC,t) in the infrared wavelength region decreases, and there is a risk that the thermal stability and chemical durability of the glass cannot be maintained. If the total content is too high, there is a risk that the viscosity of the molten glass increases, leading to poor formability. Additionally, there is a risk of a decrease in the refractive index.

[0343] In the optical glass of the second-1 embodiment, B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The cation ratio is 0.44 or higher. The lower limit of this cation ratio is preferably 0.47, and more preferably in the order of 0.50, 0.53, and 0.56. Furthermore, the upper limit of this cation ratio is preferably 0.80, and more preferably in the order of 0.75, 0.71, 0.67, 0.63, and 0.61. By setting the cation ratio within the above range, the relative partial dispersion (PC,t) in the infrared wavelength region can be improved. If the cation ratio is too small, there is a risk of a decrease in the relative partial dispersion (PC,t). If the cation ratio is too large, there is a risk of a decrease in the chemical durability of the glass.

[0344] In the optical glass of the second-1 embodiment, Li + Na + and K + The total content R, and the total content R and Mg 2+ Ca 2 + 、Sr 2+ Ba 2+ and Zn 2+The total cation ratio [R / (R+R')] of the total content R' is 0.55 or more. The lower limit of this cation ratio is preferably 0.60, and more preferably in the order of 0.65, 0.70, and 0.75. Furthermore, the upper limit of this cation ratio is preferably 1.00, and more preferably in the order of 0.95, 0.90, and 0.85. By setting this cation ratio within the above range, the relative partial dispersion PC,t in the infrared wavelength region can be improved, the solubility of the glass can be improved, and the viscosity of the molten glass can be reduced, thereby improving formability. If the cation ratio is too small, there is a risk of a decrease in the relative partial dispersion PC,t. If the cation ratio is too large, the thermal stability of the glass decreases, and there is a risk of a decrease in the refractive index nd.

[0345] It should be noted that in this specification, Li is sometimes referred to as Li. + Na + and K + The total content is called R, and sometimes Mg is used to refer to the total content of Mg. 2+ Ca 2 + 、Sr 2+ Ba 2+ and Zn 2+ The total content of is called R'.

[0346] In the optical glass of the second-1 embodiment, Nb 5+ The content of Nb exceeds 0% and is below 11.5%. 5+ The lower limit of the content is preferably 2.0%, and more preferably in the order of 3.0%, 3.5%, 4.0%, 4.5%, and 5.0%. Additionally, Nb... 5+ The upper limit of the content is preferably 10%, and more preferably in the order of 9.5%, 9.0%, 8.5%, 8.0%, 7.5%, 7.0%, 6.5%, and 6.0%. This is achieved by making Nb... 5+ With a content within the above range, high dispersibility can be maintained while suppressing the decrease in relative partial dispersion PC,t in the infrared wavelength region. 5+ When the content is too low, there is a risk that high dispersion cannot be maintained. (Nb) 5 + When the content is too high, there is a risk of a decrease in the relative partial dispersion PC,t in the infrared wavelength region.

[0347] The optical glass of the 2-1 embodiment satisfies one or more of the following (i) and (ii).

[0348] (i) In the optical glass of the second-1 embodiment, Zr 4+ The content of Mg 2+ Ca 2+ 、Sr 2+ Ba 2+and Zn 2+ Total content R', Nb 5+ Ti 4+ W 6+ Bi 3+ and Ta 5+ The total content of cation ratio [Zr 4+ / (R'+Nb 5+ +Ti 4+ +W 6+ +Bi 3+ +Ta 5+ The lower limit of the cation ratio is preferably 0.17, and more preferably in the order of 0.20, 0.25, 0.30, 0.35, 0.37, 0.39, and 0.40. Furthermore, the upper limit of the cation ratio is preferably 2.00, and more preferably in the order of 1.80, 1.60, 1.40, 1.20, 1.00, 0.80, and 0.60. From the viewpoint of improving chemical durability, increasing the refractive index nd, and maintaining high dispersion, the cation ratio is preferably within the above range. If the cation ratio is too small, there is a risk of a decrease in the refractive index nd, and there is also a risk of a decrease in the chemical durability of the glass. If the cation ratio is too large, there is a risk of an increase in the liquidus temperature LT, and there is also a risk of a decrease in stability upon reheating.

[0349] (ii) In the optical glass of the second-1 embodiment, Zr 4+ and Ta 5+ Total content, and Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ Total content R', Nb 5+ Ti 4+ W 6+ and Bi 3+ The total content of cation ratio [(Zr 4+ +Ta 5+ ) / (R'+Nb 5+ +Ti 4+ +W 6+ +Bi 3+The lower limit of the cation ratio is preferably 0.25, and more preferably in the order of 0.30, 0.35, 0.37, 0.39, and 0.40. Furthermore, the upper limit of the cation ratio is preferably 3.10, and more preferably in the order of 2.80, 2.60, 2.40, 2.20, 2.00, 1.80, 1.60, 1.40, 1.20, 1.00, 0.80, and 0.60. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the refractive index nd, maintaining high dispersion, and maintaining the chemical durability of the glass, it is preferable to set the cation ratio within the above range. If the cation ratio is too small, there is a risk of a decrease in the refractive index nd, and also a risk of a decrease in the chemical durability of the glass. If the cation ratio is too large, there is a risk of a decrease in the thermal stability of the glass.

[0350] The preferred content of the glass component in the optical glass of the second-1 embodiment is shown below.

[0351] In the optical glass of the second-1 embodiment, Zr 4+ and Ta 5+ Total content [Zr] 4+ +Ta 5+ The upper limit of the total content is preferably 8.5%, and more preferably in the order of 8.0%, 7.5%, 7.0%, 6.5%, 6.0%, and 5.5%. Furthermore, the lower limit of this total content is preferably 1.0%, and more preferably in the order of 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, and 4.5%. From the viewpoint of maintaining the thermal stability of the glass, it is preferable that the total content is within the above range. If the total content is too low, there is a risk of reduced chemical durability of the glass. If the total content is too high, there is a risk of reduced thermal stability of the glass and increased raw material costs.

[0352] In the optical glass of the second-1 embodiment, Zr 4+ The lower limit of the content is preferably 1.0%, and more preferably in the order of 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, and 4.5%. Additionally, Zr... 4+ The upper limit of the Zr content is preferably 8.5%, and more preferably in the order of 8.0%, 7.5%, 7.0%, 6.5%, 6.0%, and 5.5%. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and improving chemical durability, it is preferable to make Zr... 4+ The content of Zr is within the above range. 4+ When the content is too low, there is a risk of reduced chemical durability. 4+ When the content is too high, there is a risk of an increase in the liquid phase temperature LT, and there is also a risk of reduced stability during reheating.

[0353] In the optical glass of the second-1 embodiment, Li + Na + and K + Total content of R and Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content R' and Si 4+ and B 3+ The total content of cation ratio [(R+R') / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 1.00, and more preferably in the order of 0.90, 0.80, 0.70, 0.60, and 0.50. Furthermore, the lower limit of this cation ratio is preferably 0.10, and more preferably in the order of 0.12, 0.14, 0.16, 0.18, 0.20, 0.22, and 0.24. From the viewpoint of improving the relative partial dispersion (PC,t) in the infrared wavelength region and improving chemical durability, it is preferable that the cation ratio is within the above-mentioned range.

[0354] In the optical glass of the second-1 embodiment, B 3+ The content of Zr 4+ 、Nb 5+ Ti 4+ W 6+ Bi 3+ and Ta 5+ The total content of cation ratio [B] 3+ / (Zr 4+ +Nb 5+ +Ti 4+ +W 6+ +Bi 3+ +Ta 5+ The upper limit of the cation ratio is preferably 7.0, and more preferably in the order of 6.0, 5.5, 5.0, 4.5, and 4.0. Furthermore, the lower limit of this cation ratio is preferably 1.0, and more preferably in the order of 1.2, 1.4, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, and 2.2. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, it is preferable that the cation ratio is within the above-mentioned range.

[0355] In the optical glass of the second-1 embodiment, Zr 4+ 、Nb 5+ Ti 4+ W 6+ and Ta 5+ Total content [Zr] 4+ +Nb 5+ +Ti 4 + +W6+ +Ta 5+ The lower limit of the content is preferably 5.0%, and more preferably in the order of 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, and 10%. Furthermore, the upper limit of the total content is preferably 20%, and more preferably in the order of 19%, 18%, 17%, 16%, and 15%. From the viewpoint of increasing the refractive index nd and adjusting the Abbe number νd, it is preferable that the total content is within the above-mentioned range.

[0356] The optical glass in the second-1 embodiment preferably does not contain Pb. 2+ That is, Pb is preferred. 2+ The content of As and Th is 0%. Furthermore, As and Th, like Pb, are components with potential environmental burden. Therefore, the content of each of As and Th, expressed in oxide form, is preferably 0-0.1%, which can be 0-0.05% or 0-0.01%. The content of each of As and Th, expressed in oxide form, is preferably 0%. That is, it is preferable that neither As nor Th is substantially present.

[0357] Regarding the content and ratio of glass components other than those described above in the optical glass of Embodiment 2-1, non-limiting examples are shown below.

[0358] In the optical glass of the second-1 embodiment, P 5+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 5%, and 3%. Additionally, P... 5+ The lower limit of the content is preferably 0.1%, and more preferably in the order of 0.5%, 0.8%, and 1%. 5+ The content can also be 0%. By making P 5+ When the content is within the above range, the thermal stability of the glass can be maintained.

[0359] In the optical glass of the second-1 embodiment, Al 3+ The upper limit of the content is preferably 10%, and more preferably in the order of 8%, 6%, 4%, and 2%. Additionally, Al... 3+ The lower limit of the content is preferably 0%, and more preferably in the order of 0.01%, 0.05%, 0.10%, 0.15%, and 0.20%. 3+ The content can also be 0%. Al 3+ It has the function of suppressing phase separation of glass by containing an appropriate amount. On the other hand, from the viewpoint of maintaining the thermal stability of glass, it is preferable to use Al. 3+ The content is within the above range.

[0360] In the optical glass of the second-1 embodiment, Si 4+ B3+ and Al 3+ Total content [Si] 4+ +B 3+ +Al 3+ The lower limit of the total content is preferably 50%, and more preferably in the order of 52%, 54%, 56%, and 57%. Furthermore, the upper limit of the total content is preferably 80%, and more preferably in the order of 78%, 76%, 74%, and 72%. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, maintaining the thermal stability of the glass, and its stability upon reheating, the total content is preferably within the above-mentioned range.

[0361] In the glass of the 2-1 embodiment, Li + The upper limit of the content is preferably 50%, and more preferably in the order of 45%, 40%, 35%, 30%, 25%, 20%, 18%, and 16%. Additionally, Li... + The lower limit of the content of [Li] is preferably 0%, and more preferably in the order of 5%, 10%, and 15%. + The content can also be 0%. Li + It is a component that helps reduce the viscosity of glass. Among alkali metals, it has a greater effect on improving the relative partial dispersion PC,t in the infrared wavelength region. + Excessive content of [Li] poses a risk of reduced stability upon reheating. Additionally, [Li] + If the content is too low, there is a risk of increased viscosity in the glass.

[0362] In the glass of embodiment 2-1, Na + The upper limit of the content is preferably 50%, and more preferably in the order of 45%, 40%, 35%, 30%, 25%, 20%, 18%, and 16%. Additionally, Na... + The lower limit of the content of Na is preferably 0%, and more preferably in the order of 5%, 10%, and 12%. + With Li + Similarly, it is a component that helps reduce the viscosity of glass. Na + Excessive Na content may lead to decreased stability upon reheating. + If the content is too low, there is a risk of increased viscosity in the glass.

[0363] In the optical glass of the second-1 embodiment, K + The upper limit of the content is preferably 20%, and more preferably in the order of 15%, 10%, and 5%. Additionally, K... + The lower limit of the content is preferably 0%, and more preferably in the order of 1%, 2%, and 3%. K + The content can also be 0%.

[0364] K + It has the effect of lowering the liquidus temperature and improving the thermal stability of glass. On the other hand, K + As the content of K increases, chemical durability, weather resistance, and stability upon reheating decrease. Therefore, K + The content of [specific component] is preferably within the range described above.

[0365] In the optical glass of the second-1 embodiment, Li + Na + and K + Total content R[Li + +Na + +K + The upper limit of the total content R is preferably 50%, and more preferably in the order of 45%, 40%, 35%, 30%, and 27%. Furthermore, the lower limit of the total content R is preferably 5%, and more preferably in the order of 8%, 11%, and 13%. From the viewpoint of suppressing the decrease in stability upon reheating, it is preferable that the total content R is within the above-mentioned range.

[0366] In the optical glass of the second-1 embodiment, Li + The content of Li + Na + and K + The total content of R cation ratio [Li + The upper limit of the cation ratio is preferably 1, and more preferably in the order of 0.95, 0.90, 0.85, 0.80, 0.75, and 0.70. Furthermore, the lower limit of this cation ratio is preferably 0, and more preferably in the order of 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, and 0.60. This cation ratio can be 0. From the viewpoint of suppressing the decrease in stability upon reheating, it is preferable that the cation ratio is within the above-mentioned range.

[0367] In the optical glass of the second-1 embodiment, Na + The content of Li + Na + and K + The total content of R cation ratio [Na + The upper limit of the cation ratio is preferably 1, and more preferably in the order of 0.90, 0.80, 0.70, 0.60, 0.50, 0.40, and 0.35. Furthermore, the lower limit of this cation ratio is preferably 0, and more preferably in the order of 0.05, 0.10, 0.15, 0.20, and 0.25. This cation ratio can be 0. From the viewpoint of suppressing the decrease in stability upon reheating, it is preferable that the cation ratio is within the above-mentioned range.

[0368] In the optical glass of the second-1 embodiment, K + The content of Li + Na + and K + The total content of R cation ratio [K] + The upper limit of the cation ratio is preferably 1, and more preferably in the order of 0.95, 0.90, 0.85, 0.80, 0.75, and 0.70. Furthermore, the lower limit of this cation ratio is preferably 0, and more preferably in the order of 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, and 0.60. This cation ratio can be 0. From the viewpoint of suppressing the decrease in stability upon reheating, it is preferable that the cation ratio is within the above-mentioned range.

[0369] In the optical glass of the second-1 embodiment, Cs + The upper limit of the content is preferably 20%, and more preferably in the order of 15%, 10%, and 5%. Cs + The lower limit of the content of Cs is preferably 0%. + The content can also be 0%.

[0370] Cs + It improves the thermal stability of glass, but increasing its content poses a risk of reduced chemical durability and weather resistance. Therefore, Cs + The content of [specific component] is preferably within the range described above.

[0371] In the optical glass of the second-1 embodiment, Ti 4+ The upper limit of the content is preferably 20%, and more preferably in the order of 15%, 10%, 8%, 6%, and 4%. Additionally, Ti... 4+ The lower limit of the Ti content is preferably 0%. 4+ The content can also be 0%. By making Ti... 4+ When the content is within the above range, the desired optical constant can be achieved, and the increase in specific gravity can be suppressed.

[0372] In the optical glass of the second-1 embodiment, W 6+ The upper limit of its content is preferably 20%, and more preferably in the order of 15%, 10%, 8%, 6%, 4%, 2%, 1%, 0.5%, and 0.1%. 6+ The lower limit of its content is preferably 0%. 6+ The content can also be 0%. From the viewpoints of improving transmittance, suppressing the decrease in relative partial dispersion PC,t in the infrared wavelength region, and reducing specific gravity, it is preferable to make W... 6+ The content is within the above range.

[0373] In the optical glass of the second-1 embodiment, Bi 3+ The upper limit of the content is preferably 20%, and more preferably in the order of 15%, 10%, 8%, and 6%. Additionally, Bi... 3+ The lower limit of the content is preferably 0%, and more preferably in the order of 1%, 2%, 3%, 4%, and 5%. 3+ The content can also be 0%. From the viewpoint of increasing transmittance and reducing specific gravity, and also from the viewpoint of reducing damage to platinum manufacturing equipment, it is preferable to use Bi... 3+ The content is within the above range.

[0374] In the optical glass of the second-1 embodiment, Ta 5+ The upper limit of the content is preferably 20%, and more preferably in the order of 15%, 10%, 9%, 8%, and 6%. Additionally, Ta... 5+ The lower limit of its content is preferably 0%, and more preferably in the order of 1%, 2%, 3%, and 4%. 5+ The content can also be 0%.

[0375] Ta 5+ It is a component that imparts high refractive index and low dispersion to glass, and improves the relative partial dispersion PC,t in the infrared wavelength region. On the other hand, Ta 5+ Increased content of [a specific ingredient] leads to higher raw material costs. Furthermore, there is a risk of its proportion increasing. Therefore, Ta [is necessary / should be considered ... 5+ The content of [specific component] is preferably within the range described above.

[0376] In the optical glass of the second-1 embodiment, Nb 5+ Ti 4+ W 6+ and Bi 3+ Total content [Nb] 5+ +Ti 4+ +W 6+ +Bi 3 + The upper limit of the total content is preferably 20%, and more preferably in the order of 15%, 14%, 13%, 12%, 11%, and 10%. The lower limit of the total content is preferably 0.5%, and more preferably in the order of 1%, 2%, 3%, and 4%. From the viewpoint of maintaining a high refractive index and a desired Abbe number νd, it is preferable that the total content is within the above-mentioned range.

[0377] In the optical glass of the second-1 embodiment, Nb 5+ Ti 4+ W 6+ Bi 3+ and Ta 5+ Total content [Nb] 5+ +Ti 4++W 6 + +Bi 3+ +Ta 5+ The upper limit of the total content is preferably 20%, and more preferably in the order of 15%, 14%, 13%, 12%, 11%, and 10%. The lower limit of the total content is preferably 0.5%, and more preferably in the order of 1%, 2%, 3%, and 4%. From the viewpoint of maintaining a high refractive index and a desired Abbe number νd, it is preferable that the total content is within the above-mentioned range.

[0378] In the optical glass of the second-1 embodiment, Zr 4+ 、Nb 5+ Ti 4+ W 6+ Bi 3+ and Ta 5+ Total content [Zr] 4+ +Nb 5+ +Ti 4+ +W 6+ +Bi 3+ +Ta 5+ The upper limit of the total content is preferably 20%, and more preferably in the order of 19%, 18%, 17%, 16%, and 15%. The lower limit of the total content is preferably 5%, and more preferably in the order of 6%, 7%, 8%, 9%, and 10%. From the viewpoint of maintaining a high refractive index, it is preferable that the total content is within the above-mentioned range.

[0379] In the optical glass of the second-1 embodiment, Zr 4+ and Nb 5+ Total content [Zr] 4+ +Nb 5+ The upper limit of the total content is preferably 20%, and more preferably in the order of 19%, 18%, 17%, 16%, and 15%. The lower limit of the total content is preferably 5%, and more preferably in the order of 6%, 7%, 8%, 9%, and 10%. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and maintaining high dispersion, the total content is preferably within the above-mentioned range.

[0380] In the optical glass of the second-1 embodiment, Nb 5+ Ti 4+ W 6+ and Ta 5+ Total content [Nb] 5+ +Ti 4+ +W 6+ +Ta 5 +The upper limit of the total content is preferably 20%, and more preferably in the order of 15%, 14%, 13%, 12%, 11%, and 10%. The lower limit of the total content is preferably 0.5%, and more preferably in the order of 1%, 2%, 3%, and 4%. From the viewpoint of maintaining a high refractive index and a desired Abbe number νd, it is preferable that the total content is within the above-mentioned range.

[0381] In the optical glass of the second-1 embodiment, Nb 5+ The content of Nb 5+ Ti 4+ W 6+ and Ta 5+ The total content of cation ratio [Nb] 5+ / (Nb 5+ +Ti 4+ +W 6+ +Ta 5+ The upper limit of the cation ratio is preferably 1, and more preferably in the order of 0.99, 0.98, 0.97, 0.96, 0.95, 0.94, 0.93, 0.92, and 0.91. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.5, 0.6, 0.7, 0.8, and 0.9. The cation ratio can be 1. From the viewpoint of maintaining a high refractive index, it is preferable that the cation ratio is within the above-mentioned range.

[0382] In the optical glass of the second-1 embodiment, Ta 5+ The content of Nb 5+ Ti 4+ W 6+ and Ta 5+ The total content of cation ratio [Ta 5+ / (Nb 5+ +Ti 4+ +W 6+ +Ta 5+ The upper limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.4, 0.3, 0.2, and 0.1. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.03, 0.05, and 0.07. The cation ratio can be 0. From the viewpoint of suppressing the increase in raw material costs, it is preferable to make the cation ratio within the above range.

[0383] In the optical glass of the second-1 embodiment, Ti 4+ The content of Nb 5+ Ti 4+ W 6+ and Ta 5+ The total content of cation ratio [Ti 4+ / (Nb 5+ +Ti 4+ +W 6++Ta 5+ The upper limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.4, 0.3, 0.2, and 0.1. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.03, 0.05, and 0.07. The cation ratio can be 0. From the viewpoint of maintaining a high refractive index, it is preferable that the cation ratio is within the above-mentioned range.

[0384] In the optical glass of the second-1 embodiment, Zr 4+ The content of Zr 4+ 、Nb 5+ Ti 4+ W 6+ and Ta 5+ The total content of cation ratio [Zr 4+ / (Zr 4+ +Nb 5+ +Ti 4+ +W 6+ +Ta 5+ The upper limit of the cation ratio is preferably 0.9, and more preferably in the order of 0.8, 0.7, 0.6, and 0.55. The lower limit of the cation ratio is preferably 0.01, and more preferably in the order of 0.10, 0.15, 0.20, 0.25, and 0.30. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and maintaining high dispersibility, it is preferable to make the cation ratio within the above-mentioned range.

[0385] In the optical glass of the second-1 embodiment, Nb 5+ The content of Zr 4+ 、Nb 5+ Ti 4+ W 6+ and Ta 5+ The total content of cation ratio [Nb] 5+ / (Zr 4+ +Nb 5+ +Ti 4+ +W 6+ +Ta 5+ The upper limit of the cation ratio is preferably 0.9, and more preferably in the order of 0.8, 0.75, and 0.7. The lower limit of the cation ratio is preferably 0.1, and more preferably in the order of 0.2, 0.3, 0.4, and 0.45. From the viewpoint of maintaining high dispersibility, it is preferable that the cation ratio is within the above-mentioned range.

[0386] In the optical glass of the second-1 embodiment, Ta 5+ The content of Zr 4+ 、Nb 5+ Ti 4+ W 6+ and Ta 5+The total content of cation ratio [Ta 5+ / (Zr 4+ +Nb 5+ +Ti 4+ +W 6+ +Ta 5+ The upper limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.4, 0.3, 0.2, and 0.1. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.03, 0.05, and 0.07. The cation ratio can be 0. From the viewpoint of suppressing the increase in raw material costs, it is preferable to make the cation ratio within the above range.

[0387] In the optical glass of the second-1 embodiment, Ti 4+ The content of Zr 4+ 、Nb 5+ Ti 4+ W 6+ and Ta 5+ The total content of cation ratio [Ti 4+ / (Zr 4+ +Nb 5+ +Ti 4+ +W 6+ +Ta 5+ The upper limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.4, 0.3, 0.2, and 0.1. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.03, 0.05, and 0.07. The cation ratio can be 0. From the viewpoint of maintaining high dispersibility, it is preferable that the cation ratio is within the above-mentioned range.

[0388] In the optical glass of the second-1 embodiment, Mg 2+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 5%, 4%, 3%, 2%, and 1%. Additionally, Mg... 2+ The lower limit of Mg content is preferably 0%. 2+ The content can also be 0%.

[0389] Mg 2+ It is the component of alkaline earth metals that enhances the relative partial dispersion PC,t in the infrared wavelength region. However, Mg 2+ When the content of Mg increases, high dispersion is impaired, and there is a risk of reduced thermal stability and devitrification resistance of the glass. Therefore, Mg 2+ The content of [specific component] is preferably within the range described above.

[0390] In the optical glass of the second-1 embodiment, Ca 2+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 5%, 4%, 3%, 2%, and 1%. Additionally, Ca... 2+The lower limit of the content of Ca is preferably 0%. 2+ The content can also be 0%.

[0391] Ca 2+ It is the component of alkaline earth metals that enhances the relative partial dispersion PC,t in the infrared wavelength region. However, Ca 2+ When the content of Ca increases, high dispersion is impaired, and there is a risk of reduced thermal stability and devitrification resistance of the glass. Therefore, Ca 2+ The content of [specific component] is preferably within the range described above.

[0392] In the optical glass of the second-1 embodiment, Sr 2+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 5%, 4%, 3%, 2%, and 1%. Additionally, Sr... 2+ The lower limit of the content of Sr is preferably 0%. 2+ The content can also be 0%.

[0393] Sr 2+ It is a component in alkaline earth metals that increases the refractive index. However, Sr... 2+ When the content of Sr increases, high dispersion is impaired, and there is a risk of a decrease in the relative partial dispersion PC,t in the infrared wavelength region. Therefore, Sr 2+ The content of [specific component] is preferably within the range described above.

[0394] In the optical glass of the second-1 embodiment, Ba 2+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 9%, 8%, 7%, 6%, 5%, and 4.5%. Ba 2+ The lower limit of the content is preferably 0%, and more preferably in the order of 1.0%, 1.5%, and 2.0%. Ba 2+ The content can also be 0%.

[0395] Ba 2+ It is a component that increases the refractive index and also lowers the liquidus temperature, thus improving the thermal stability of the glass. However, Ba... 2+ Excessive content of Ba impairs high dispersion and poses a risk of reduced relative partial dispersion (PC,t) in the infrared wavelength region. Additionally, Ba... 2+ When the content of Ba is too low, the refractive index nd decreases, and there is a risk of reduced thermal stability and devitrification resistance of the glass. Therefore, Ba 2+ The content of [specific component] is preferably within the range described above.

[0396] In the optical glass of the second-1 embodiment, Zn 2+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 5%, 4%, 3%, 2%, and 1%. Additionally, Zn... 2+The lower limit of the content is preferably 0%, and more preferably in the order of 0.1%, 0.5%, and 0.7%. Zn 2+ The content can also be 0%.

[0397] Zn 2+ It is a glass component that improves the thermal stability of glass. However, Zn 2+ Excessive Zn content poses a risk of increased specific gravity and a potential decrease in relative partial dispersion (PC,t) in the infrared wavelength region. Therefore, from the perspective of improving the thermal stability of glass and maintaining desired optical constants, Zn... 2+ The content of [specific component] is preferably within the range described above.

[0398] In the optical glass of the second-1 embodiment, Mg 2+ Ca 2+ 、Sr 2+ And Ba 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The upper limit of the total content is preferably 20%, further preferably in the order of 15%, 10%, 9%, 8%, 7%, 6%, 5%, and 4%. The lower limit of the total content is preferably 0%, further preferably in the order of 0.3%, 0.6%, 0.9%, 1.0%, 1.2%, 1.5%, 1.7%, and 1.9%. Mg 2+ Ca 2+ 、Sr 2+ , and Ba 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The total content can be 0%. If this total content is too high, high dispersion is compromised, and there is a risk of a decrease in the relative partial dispersion PC,t in the infrared wavelength region. Conversely, if this total content is too low, the refractive index nd decreases, and there is a risk of a decrease in the glass's thermal stability and devitrification resistance. Therefore, the total content is preferably within the above-mentioned range.

[0399] In the optical glass of the second-1 embodiment, Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ Total content R'[Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+The upper limit of the total content R' is preferably 20%, and more preferably in the order of 15%, 10%, 9%, 8%, 7%, 6%, 5%, and 4%. The lower limit of the total content R' is preferably 0%, and more preferably in the order of 0.3%, 0.6%, 0.9%, 1.0%, 1.2%, 1.5%, 1.7%, and 1.9%. The total content R' can be 0%. When the total content R' is too high, the high dispersion is impaired, and there is a risk of a decrease in the relative partial dispersion PC,t in the infrared wavelength region. In addition, when the total content R' is too low, the refractive index nd decreases, and there is a risk of a decrease in the thermal stability and devitrification resistance of the glass. Therefore, the total content R' is preferably within the above range.

[0400] In the glass of the 2-1 embodiment, Y 3+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 5%, 4%, and 3%. Additionally, Y... 3+ The lower limit of the content of Y is preferably 0%, and more preferably in the order of 1% and 2%. 3+ The content can also be 0%.

[0401] By importing a certain amount of Y 3+ This can increase the refractive index nd. However, Y 3+ When the content of Y is too high, the thermal stability of the glass decreases, making it more prone to devitrification during manufacturing. Additionally, there is a risk of damage to high dispersion. Therefore, from the perspective of suppressing the decrease in the thermal stability of the glass, Y... 3+ The content of [specific component] is preferably within the range described above.

[0402] In the glass of the second-1 embodiment, Sc 3+ The content of is preferably 2% or less. Additionally, Sc 3+ The lower limit of its content is preferably 0%.

[0403] In the glass of the 2-1 embodiment, Hf 4+ The content of Hf is preferably below 2%. 4+ The lower limit of its content is preferably 0%.

[0404] Sc 3+ Hf 4+ It has the effect of improving the dispersion of glass, but it is an expensive component. Therefore, Sc 3+ Hf 4+ The preferred content of each is within the range described above.

[0405] In the glass of the second-1 embodiment, Lu 3+ The content of [specific component] is preferably 2% or less. Additionally, Lu [is also present]. 3+ The lower limit of its content is preferably 0%.

[0406] Lu3+ It has the effect of improving the dispersion of glass, but due to its large molecular weight, it is also a glass component that increases the specific gravity of glass. Therefore, Lu 3+ The content of [specific component] is preferably within the range described above.

[0407] In the glass of the second-1 embodiment, Ge 4+ The content of [specific component] is preferably 2% or less. Additionally, Ge [specific component]... 4+ The lower limit of its content is preferably 0%.

[0408] Ge 4+ Ge has the effect of improving the dispersion of glass, but it is a very expensive component in commonly used glass compositions. Therefore, from the perspective of reducing the manufacturing cost of glass, Ge... 4+ The content of [specific component] is preferably within the range described above.

[0409] In the optical glass of the second-1 embodiment, La 3+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 5%, 4%, and 3%. Additionally, La... 3+ The lower limit of the content is preferably 0%, and more preferably in the order of 1% and 2%. 3+ The content can also be 0%. This can be achieved by introducing a certain amount of La... 3+ This can increase the refractive index nd. However, La 3+ When the content of La is too high, the thermal stability of the glass decreases, making it more prone to devitrification during manufacturing. Additionally, there is a risk of damage to high dispersion, specifically a decrease in the relative partial dispersion (PC,t) in the infrared wavelength region. Therefore, La... 3+ The content of [specific component] is preferably within the range described above.

[0410] In the glass of the second-1 embodiment, Gd 3+ The content of Gd is preferably below 2%. 3+ The lower limit of its content is preferably 0%.

[0411] Gd 3+ Excessive Gd content reduces the thermal stability of the glass. Additionally, Gd... 3+ Excessive Gd content increases the specific gravity of the glass, which is undesirable. Furthermore, it poses a risk of increased raw material costs. Therefore, from the perspective of maintaining good thermal stability of the glass while suppressing the increase in specific gravity, Gd... 3+ The content of [specific component] is preferably within the range described above.

[0412] In the glass of the second-1 embodiment, La 3+ Gd 3+ and Y 3+ Total content [La 3+ +Gd 3++Y 3+ The upper limit of the total content is preferably 20%, and more preferably in the order of 10%, 5%, 4%, 3%, 2%, and 1%. The lower limit of the total content is preferably 0%. From the viewpoint of suppressing the decrease in the thermal stability of the glass and preventing the decrease in the relative partial dispersion PC,t in the infrared wavelength region, it is preferable to make the total content within the above range.

[0413] In the glass of the 2-1 embodiment, Yb 3+ The content of Yb is preferably below 2%. 3+ The lower limit of its content is preferably 0%.

[0414] with La 3+ Gd 3+ Y 3+ In comparison, Yb 3+ The large molecular weight of Yb increases the specific gravity of the glass. Additionally, Yb... 3+ When the content of Yb is too high, the thermal stability of the glass decreases. From the perspective of preventing a decrease in the thermal stability of the glass and inhibiting an increase in specific gravity, Yb... 3+ The content of [specific component] is preferably within the range described above.

[0415] In the glass of the 2-1 embodiment, Li + Na + and K + Total content R and Si 4+ and B 3+ The total content of cations [R / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 2.0, and more preferably in the order of 1.5, 1.0, 0.9, 0.8, 0.7, 0.6, and 0.5. The lower limit of the cation ratio is preferably 0.01, and more preferably in the order of 0.02, 0.04, 0.06, 0.08, 0.10, 0.12, and 0.14. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and improving chemical durability, it is preferable that the cation ratio is within the above-mentioned range.

[0416] In the glass of embodiment 2-1, Mg 2+ Ca 2+ 、Sr 2+ And Ba 2+ Total content and Si 4+ and B 3+ The total content of cations [(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ) / (Si 4+ +B 3+The upper limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.4, 0.3, 0.2, 0.1, and 0.08. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.01, 0.02, and 0.03. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and improving chemical durability, it is preferable that the cation ratio is within the above-mentioned range.

[0417] In the glass of embodiment 2-1, Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content R' and Si 4+ and B 3+ The total content of cation ratio [R' / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.4, 0.3, 0.2, 0.1, and 0.08. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.01, 0.02, and 0.03. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and improving chemical durability, it is preferable that the cation ratio is within the above-mentioned range.

[0418] In the glass of the second-1 embodiment, La 3+ Gd 3+ and Y 3+ Total content and Si 4+ and B 3+ The total content of cation ratio [(La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.4, 0.3, 0.2, 0.1, and 0.08. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.01, 0.02, and 0.03. The cation ratio can be 0. From the viewpoint of suppressing the decrease in the thermal stability of the glass, it is preferable that the cation ratio is within the above-mentioned range.

[0419] In the glass of the 2-1 embodiment, Nb 5+ Ti 4+ W 6+ and Ta 5+ Total content and Si 4+ and B 3+ The total content of cation ratio [(Nb 5+ +Ti 4+ +W 6+ +Ta 5+) / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 0.50, and more preferably in the order of 0.40, 0.35, 0.30, 0.25, and 0.20. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.02, 0.04, and 0.06. From the viewpoint of maintaining a high refractive index and a desired Abbe number νd, it is preferable that the cation ratio is within the above-mentioned range.

[0420] In the glass of embodiment 2-1, Mg 2+ Ca 2+ 、Sr 2+ , and Ba 2+ Total content and Li + Na + and K + The total content of R cation ratio [(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The upper limit of the cation ratio is preferably 0.6, and more preferably in the order of 0.5, 0.4, and 0.35. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.02, 0.04, and 0.06. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and improving the formability by reducing the viscosity of the molten glass, the cation ratio is preferably within the above-mentioned range.

[0421] In the glass of embodiment 2-1, Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ Total content R' and Li + Na + and K + The upper limit of the cation ratio [R' / R] of the total content R is preferably 0.6, and more preferably in the order of 0.5, 0.4, and 0.35. The lower limit of this cation ratio is preferably 0, and more preferably in the order of 0.02, 0.04, and 0.06. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and improving the formability by reducing the viscosity of the molten glass, it is preferable to make the cation ratio within the above range.

[0422] In the glass of the second-1 embodiment, La 3+ Gd 3+ and Y 3+ Total content and Li + Na + and K +The total content of R cation ratio [(La 3+ +Gd 3+ +Y 3+ The upper limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.4, 0.3, and 0.2. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.01, 0.03, and 0.05. The cation ratio can be 0. From the viewpoint of suppressing the decrease in the thermal stability of the glass, it is preferable that the cation ratio is within the above range.

[0423] In the glass of the 2-1 embodiment, Nb 5+ Ti 4+ W 6+ and Ta 5+ Total content and Li + Na + and K + The total content of R cation ratio [(Nb 5+ +Ti 4+ +W 6+ +Ta 5+ The upper limit of the cation ratio is preferably 0.60, and more preferably in the order of 0.55, 0.50, 0.45, and 0.40. The lower limit of the cation ratio is preferably 0.05, and more preferably in the order of 0.10, 0.15, and 0.17. From the viewpoint of maintaining a high refractive index, improving the solubility of the glass, and reducing the viscosity of the molten glass to improve formability, the cation ratio is preferably within the above-mentioned range.

[0424] In the glass of the 2-1 embodiment, Li + Na + and K + The total content R and the total content R, Mg 2+ Ca 2+ 、Sr 2+ And Ba 2+ The total content of cation ratio [R / (R+Mg)] 2+ +Ca 2+ +Sr 2+ +Ba 2+ The upper limit of the cation ratio is preferably 1, and more preferably in the order of 0.99, 0.98, 0.97, 0.96, 0.95, and 0.94. The lower limit of the cation ratio is preferably 0.50, and more preferably in the order of 0.55, 0.60, 0.65, 0.70, and 0.75. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and improving the formability by reducing the viscosity of the molten glass, the cation ratio is preferably within the above-mentioned range.

[0425] In the glass of the 2-1 embodiment, Li +Na + and K + Total content R, Mg 2+ and Ca 2+ The total content and the total content of R and Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content R' of the total cation ratio [(R+Mg 2+ +Ca 2+ The upper limit of the cation ratio [(R+R')] is preferably 1, and more preferably in the order of 0.99, 0.98, 0.97, 0.96, 0.95, and 0.94. The lower limit of the cation ratio is preferably 0.50, and more preferably in the order of 0.55, 0.60, 0.65, 0.70, and 0.75. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and improving the formability by reducing the viscosity of the molten glass, the cation ratio is preferably within the above-mentioned range.

[0426] In the glass of the second-1 embodiment, La 3+ Gd 3+ and Y 3+ Total content and Nb 5+ Ti 4+ W 6+ and Ta 5+ The total content of cation ratio [(La 3+ +Gd 3+ +Y 3+ ) / (Nb 5+ +Ti 4+ +W 6+ +Ta 5+ The upper limit of the cation ratio is preferably 1, and more preferably in the order of 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.1. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.01, 0.02, 0.03, 0.04, and 0.05. The cation ratio can be 0. From the viewpoint of suppressing the decrease in the thermal stability of the glass and maintaining a high refractive index, it is preferable that the cation ratio is within the above-mentioned range.

[0427] The glass in the preferred embodiment 2-1 is mainly composed of the above-described glass composition, namely, Si, which is an essential component. 4+ B 3+ Zr 4+ and Nb 5+ P as an arbitrary component 5+ Al 3+ Li + Na +K + Cs + Ti 4+ W 6+ Bi 3+ Ta 5+ Mg 2+ Ca 2+ 、Sr 2+ Ba 2 + Zn 2+ Y 3+ ,Sc 3+ Hf 4+ Lu 3+ 、Ge 4+ La 3+ Gd 3+ and Yb 3+ Composition. The total content of the above-mentioned glass components is preferably 95% or more, more preferably 98% or more, even more preferably 99% or more, and particularly preferably 99.5% or more.

[0428] The optical glass of embodiment 2-1 contains O as an anionic component. 2- O 2- The preferred content is 90-100% anion, more preferably 95-100% anion.

[0429] The optical glass of embodiment 2-1 may contain F as an anionic component. - .

[0430] F - The preferred content is 0-10% anion, more preferably 0-5% anion.

[0431] The optical glass of embodiment 2-1 may contain O-removal components. 2- and F - Other than O, it is used as an anionic component. 2- and F - Other anionic components, such as Cl, can be used as examples. - ,Br - I - However, Cl - ,Br - I - All of these components readily volatilize during the glass melting process. This volatilization leads to problems such as changes in glass properties, reduced glass homogeneity, and significantly increased wear and tear on melting equipment. Therefore, Cl... - The content of Br is preferably less than 5% anion, more preferably less than 3% anion, even more preferably less than 1% anion, particularly preferably less than 0.5% anion, and even more preferably less than 0.25% anion. Additionally, Br- and I - The total content is preferably less than 5% anions, more preferably less than 3% anions, even more preferably less than 1% anion, particularly preferably less than 0.5% anions, even more preferably less than 0.1% anions, and even more preferably 0% anions.

[0432] The glass in the second-first embodiment is preferably composed of the glass composition described above, but may contain other components to the extent that it does not impair the effects of the present invention. Furthermore, the presence of unavoidable impurities is not excluded in the present invention.

[0433] In addition to the components mentioned above, the optical glass may also contain small amounts of Sb. 3+ (Sb2O3) and the like are used as clarifying agents. The total amount of clarifying agent (additional amount) is preferably 0% or more and less than 1%, more preferably 0% or more and less than 0.5%, 0% or more and less than 0.3%, 0% or more and less than 0.2%, 0% or more and less than 0.1%, 0% or more and less than 0.05%, or 0% or more and less than 0.03%.

[0434] Additional addition refers to the amount of clarifying agent added, expressed as a weight percentage, when the total content of all glass components other than the clarifying agent is set to 100%.

[0435] Furthermore, the aforementioned optical glass can achieve high transmittance across a wide range of the visible light spectrum. To fully utilize this advantage, it is preferable to avoid containing coloring elements. Examples of coloring elements include Cu, Co, Ni, Fe, Cr, Eu, Nd, Er, V, and Ag. Preferably, all elements are below 100 ppm by mass, more preferably 0 to 80 ppm by mass, even more preferably 0 to 50 ppm by mass, and particularly preferably substantially absent.

[0436] Ga, Te, Tb, etc. are components that do not need to be introduced and are also expensive components. Therefore, the content of Ga2O3, TeO2, and TbO2, expressed in mass %, is preferably 0 to 0.1%, more preferably 0 to 0.05%, further preferably 0 to 0.01%, even more preferably 0 to 0.005%, even more preferably 0 to 0.001%, and particularly preferably substantially not contained.

[0437] In the optical glass of the second-first embodiment, the glass properties can be the same as those of the first-first embodiment.

[0438] The manufacturing of the optical glass and optical components in the second-first embodiment can be the same as in the first-first embodiment.

[0439] Implementation Method 2-2

[0440] In the optical glass of embodiment 2-2,

[0441] As a component of glass

[0442] Contains Si 4+ B 3+ Zr 4+ and Nb 5+ ,

[0443] And contains selected from Li + Na + and K + One or more of them

[0444] The ΔPC,t of the optical glass is 0.0250 or higher.

[0445] The optical glass in embodiment 2-2 contains Si 4+ As a glass component, Si 4+ The lower limit of the content is preferably 10%, and more preferably in the order of 12%, 14%, 16%, 18%, 20%, 22%, 23%, and 24%. Additionally, Si... 4+ The upper limit of the content is preferably 50%, and more preferably in the order of 43%, 40%, 38%, 36%, 34%, 32%, and 30%. Si 4+ It is a network-forming component of glass. It contains Si. 4+ This can improve the relative partial dispersion (PC,t) in the infrared wavelength region, thereby improving chemical durability. From the viewpoint of suppressing the decrease in relative partial dispersion (PC,t) in the infrared wavelength region and suppressing the decrease in the thermal stability and chemical durability of the glass, the lower limit of the SiO2 content is preferably set as described above. From the viewpoint of suppressing the decrease in the solubility of the glass and preventing the viscosity of the molten glass from increasing and thus deteriorating its formability, the upper limit of the SiO2 content is preferably set as described above.

[0446] The optical glass in embodiment 2-2 contains B 3+ As a component of glass. B 3+ The lower limit of the content is preferably 20%, and more preferably in the order of 25%, 28%, 29%, 30%, 31%, and 32%. Additionally, B... 3+ The upper limit of its content is preferably 60%, and more preferably in the order of 55%, 50%, 48%, 46%, and 44%. 3+ It is a network-forming component of glass. Through the presence of B... 3+ As a glass component, it can improve the relative partial dispersion (PC,t) in the infrared wavelength region. From the viewpoint of suppressing the decrease in relative partial dispersion (PC,t) in the infrared wavelength region and suppressing the decrease in the thermal stability of the glass, B... 3+The lower limit of the content of [B] is preferably set as described above. From the viewpoint of suppressing the reduction of the chemical durability of the glass, [B] 3+ The upper limit of the content is preferably set as described above.

[0447] The optical glass in embodiment 2-2 contains Zr. 4+ Zr is a component of glass. 4+ The lower limit of the content is preferably 1.0%, and more preferably in the order of 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, and 4.5%. Additionally, Zr... 4+ The upper limit of the content is preferably 8.5%, and more preferably in the order of 8.0%, 7.5%, 7.0%, 6.5%, 6.0%, and 5.5%. This is achieved by including Zr... 4+ As a glass component, Zr can improve the relative partial dispersion (PC,t) in the infrared wavelength region, thereby improving chemical durability. From the perspective of suppressing the reduction of chemical durability, Zr... 4+ The lower limit of Zr content is preferably set as described above. From the viewpoint of suppressing the rise in liquid phase temperature LT and suppressing the decrease in stability upon reheating, Zr... 4+ The upper limit of the content is preferably set as described above.

[0448] The optical glass in embodiment 2-2 contains Nb 5+ As a component of glass. Nb 5+ The content of Nb is preferably greater than 0%, and more preferably in the order of 2.0%, 3.0%, 3.5%, 4.0%, 4.5%, and 5.0%. Additionally, Nb... 5+ The upper limit of the content is preferably 11.5%, and more preferably in the order of 10%, 9.5%, 9.0%, 8.5%, 8.0%, 7.5%, 7.0%, 6.5%, and 6.0%. This is achieved by containing Nb. 5+ As a glass composition, Nb can maintain high dispersibility while suppressing the decrease in relative partial dispersion PC,t in the infrared wavelength region. From the viewpoint of maintaining high dispersibility, Nb... 5+ The lower limit of Nb content is preferably set as described above. From the viewpoint of suppressing the decrease in relative partial dispersion PC,t in the infrared wavelength region, Nb... 5+ The upper limit of the content is preferably set as described above.

[0449] The optical glass in embodiment 2-2 contains a material selected from Li. + Na + and K + One or more of the following are used as glass components. Preferably, it contains Na. + It may contain Li + And Na + It can contain Na + and K+ It may contain Li + and K + It may contain Li + Na + and K + Through the presence of Li + Na + and K + Using one or more of these components as glass can improve the relative partial dispersion PC,t in the infrared wavelength region, thereby improving chemical durability.

[0450] In the optical glass of the second-2nd embodiment, Si 4+ and B 3+ Total content [Si] 4+ +B 3+ The lower limit of the total content is preferably 50%, and more preferably in the order of 52%, 54%, 56%, and 57%. Furthermore, the upper limit of the total content is preferably 80%, and more preferably in the order of 78%, 76%, 74%, 72%, and 71%. From the viewpoint of improving the relative partial dispersion (PC,t) in the infrared wavelength region and maintaining the thermal stability of the glass, it is preferable that the total content is within the above-mentioned range. If the total content is too low, the relative partial dispersion (PC,t) in the infrared wavelength region decreases, and there is a risk that the thermal stability and chemical durability of the glass cannot be maintained. If the total content is too high, there is a risk that the viscosity of the molten glass increases, resulting in poor formability. Additionally, there is a risk of a decrease in the refractive index.

[0451] In the optical glass of the second-2nd embodiment, B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The lower limit of the cation ratio is preferably 0.44, and more preferably in the order of 0.47, 0.50, 0.53, and 0.56. Furthermore, the upper limit of the cation ratio is preferably 0.80, and more preferably in the order of 0.75, 0.71, 0.67, 0.63, and 0.61. From the viewpoint of improving the relative partial dispersion (PC,t) in the infrared wavelength region, it is preferable that the cation ratio is within the above-mentioned range. If the cation ratio is too small, there is a risk of a decrease in the relative partial dispersion (PC,t). If the cation ratio is too large, there is a risk of a decrease in the chemical durability of the glass.

[0452] In the optical glass of the second-2nd embodiment, Li + Na + and K + The total content R, and the total content R and Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The lower limit of the total cation ratio [R / (R+R')] of the total content R' is preferably 0.55, and more preferably in the order of 0.60, 0.65, 0.70, and 0.75. Furthermore, the upper limit of this cation ratio is preferably 1.00, and more preferably in the order of 0.95, 0.90, and 0.85. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and improving the formability by reducing the viscosity of the molten glass, it is preferable to have this cation ratio within the above range. If the cation ratio is too small, there is a risk of a decrease in the relative partial dispersion PC,t. If the cation ratio is too large, the thermal stability of the glass decreases, and there is a risk of a decrease in the refractive index nd.

[0453] The optical glass of the second-2 embodiment preferably satisfies one or more of the following (i) and (ii).

[0454] (i) In the optical glass of the second-2nd embodiment, Zr 4+ The content of Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ Total content R', Nb 5+ Ti 4+ W 6+ Bi 3+ and Ta 5+ The total content of cation ratio [Zr 4+ / (R'+Nb 5+ +Ti 4+ +W 6+ +Bi 3+ +Ta 5+ The lower limit of the cation ratio is preferably 0.17, and more preferably in the order of 0.20, 0.25, 0.30, 0.35, 0.37, 0.39, and 0.40. Furthermore, the upper limit of the cation ratio is preferably 2.00, and more preferably in the order of 1.80, 1.60, 1.40, 1.20, 1.00, 0.80, and 0.60. From the viewpoint of improving chemical durability, increasing the refractive index nd, and maintaining high dispersion, the cation ratio is preferably within the above range. If the cation ratio is too small, there is a risk of a decrease in the refractive index nd, and there is also a risk of a decrease in the chemical durability of the glass. If the cation ratio is too large, there is a risk of an increase in the liquidus temperature LT, and there is also a risk of a decrease in stability upon reheating.

[0455] (ii) In the optical glass of the second-2nd embodiment, Zr 4+and Ta 5+ Total content and Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ Total content R', Nb 5+ Ti 4+ W 6+ and Bi 3+ The total content of cation ratio [(Zr 4+ +Ta 5+ ) / (R'+Nb 5+ +Ti 4+ +W 6+ +Bi 3+ The lower limit of the cation ratio is preferably 0.25, and more preferably in the order of 0.30, 0.35, 0.37, 0.39, and 0.40. Furthermore, the upper limit of the cation ratio is preferably 3.10, and more preferably in the order of 2.80, 2.60, 2.40, 2.20, 2.00, 1.80, 1.60, 1.40, 1.20, 1.00, 0.80, and 0.60. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the refractive index nd, maintaining high dispersion, and maintaining the chemical durability of the glass, the cation ratio is preferably within the above range. If the cation ratio is too small, there is a risk of a decrease in the refractive index nd, and there is also a risk of a decrease in the chemical durability of the glass. If the cation ratio is too large, there is a risk of a decrease in the thermal stability of the glass.

[0456] In the optical glass of the 2-2 embodiment, the content and ratio of glass components other than those described above can be the same as in the 2-1 embodiment.

[0457] In the optical glass of the second-2 embodiment, the deviation ΔPC,t is 0.0250 or higher. The lower limit of the deviation ΔPC,t is preferably 0.0270, and more preferably in the order of 0.0290, 0.0310, 0.0330, 0.0350, and 0.0370. By making the deviation ΔPC,t within the above range, optical glass suitable for compensating for higher-order chromatic aberrations can be obtained. On the other hand, the upper limit of the deviation ΔPC,t is not particularly limited, and is typically 0.0900, preferably 0.0800. It should be noted that the method for calculating the deviation ΔPC,t is as described in the first-1 embodiment.

[0458] In the optical glass of the second-2nd embodiment, the glass properties other than those described above can be the same as those of the first-1st embodiment.

[0459] The manufacturing of the optical glass and optical components in the second-second embodiment can be the same as in the first-first embodiment.

[0460] Third implementation method

[0461] In the third embodiment (3-1, 3-2, 3-3, and 3-4 embodiments), the glass composition of the optical glass is expressed as cation percent unless otherwise specified. In the 3-1 embodiment, the optical glass of the present invention is described based on its glass composition and the relative partial dispersion PC,t expressed as a function of the Abbe number νd. In the 3-2 embodiment, the optical glass of the present invention is described based on its glass composition. In the 3-3 embodiment, the optical glass of the present invention is described by expressing the relationship between ΔPC,t and ΔPg,F as a function of ΔPg,F. In the 3-4 embodiment, the optical glass of the present invention is described by expressing the relative partial dispersion PC,t as a function of the Abbe number νd.

[0462] Implementation Method 3-1

[0463] In the oxide optical glass of embodiment 3-1

[0464] Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ Total content [Nb] 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The figure is above 6.5%.

[0465] Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The value is above 0.55.

[0466] Zr 4+ The content of Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Zr 4+ / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The value is above 0.4.

[0467] Si 4+ B 3+ Li + Na + K + and Zr 4+ Total content and Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [(Si 4+ +B 3+ +Li + +Na + +K + +Zr 4+ ) / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The value is above 8.6.

[0468] The oxide optical glass is substantially free of Pb and As.

[0469] The PC,t of the oxide optical glass satisfies the following equation [2-2]:

[0470] PC,t≥0.5711+0.004667×νd···[2-2],

[0471] The oxide optical glass satisfies one or more of the following conditions (I) to (IV).

[0472] (I)Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K +) / (Si 4+ +B 3+ The value is below 0.85.

[0473] (II)Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The value is below 0.97.

[0474] Li + Na + Mg 2+ and Ca 2+ Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +Mg 2+ +Ca 2+ ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The value is above 0.75.

[0475] (III)B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The value is above 0.46.

[0476] (IV)Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ [B] is above 0.75 3+ and Li + Total content and Si 4+ Na + and K + The total content of cation ratio [(B 3+ +Li + ) / (Si 4+ +Na + +K + The value is above 0.31.

[0477] In the optical glass of embodiment 3-1, Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ Total content [Nb] 5+ +Ti 4+ +Ta 5 + +W 6+ +Bi 3+ The content is 6.5% or more. The lower limit of this total content is preferably 7%, 7.5%, 8%, and 8.5% in that order. Furthermore, the upper limit of this total content is preferably 30%, and further preferably 20%, 15%, 12%, 11.5%, 11%, 10.5%, and 10% in that order. By keeping the total content within the above range, a high refractive index and a desired Abbe number νd can be maintained.

[0478] In the optical glass of embodiment 3-1, Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2 + Ba 2+ and Zn 2+The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The cation ratio is 0.55 or higher. The lower limit of this cation ratio is preferably 0.75, and more preferably in the order of 0.80, 0.85, and 0.90. Furthermore, the upper limit of this cation ratio is preferably 1.00, and more preferably in the order of 0.98, 0.96, and 0.94. By setting the cation ratio within the above range, the relative partial dispersion (PC,t) in the infrared wavelength region can be improved, the solubility of the glass can be improved, and the viscosity of the molten glass can be reduced, thereby improving formability. If the cation ratio is too small, there is a risk of a decrease in the relative partial dispersion (PC,t). If the cation ratio is too large, the thermal stability of the glass decreases, and there is a risk of a decrease in the refractive index (nd).

[0479] In the optical glass of the 3-1 embodiment, Zr 4+ The content of Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Zr 4+ / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The cation ratio is 0.4 or higher. The lower limit of this cation ratio is preferably 0.42, and more preferably in the order of 0.44, 0.46, 0.48, and 0.50. The upper limit of this cation ratio is preferably 1, and more preferably in the order of 0.9, 0.8, 0.7, 0.65, 0.6, and 0.55. By setting the cation ratio within the above range, the relative partial dispersion PC,t in the infrared wavelength region can be improved, while maintaining high dispersibility.

[0480] In the optical glass of embodiment 3-1, Si 4+ B 3+ Li + Na + K + and Zr 4+ Total content and Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi3+ The total content of cation ratio [(Si 4+ +B 3+ +Li + +Na + +K + +Zr 4+ ) / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3 + The cation ratio is 8.6 or higher. The lower limit of this cation ratio is preferably 8.8, and more preferably in the order of 9.0, 9.2, 9.4, 9.6, and 9.8. The upper limit of this cation ratio is preferably 20, and more preferably in the order of 18, 16, 14, 13, 12, and 11. By setting the cation ratio to the above range, the relative partial dispersion PC,t in the infrared wavelength region can be improved, and the Abbe number can be adjusted.

[0481] The optical glass of embodiment 3-1 is substantially free of Pb and As, which are components with potential environmental burden. That is, the content of each Pb ion and As ion is 0%. Furthermore, Th, like Pb and As, is a component with potential environmental burden. Therefore, the content of Th ions is preferably 0 to 0.1%, and can be 0 to 0.05% or 0 to 0.01%. The content of Th ions is preferably 0%. That is, it is preferable that it is substantially free of Th. It should be noted that Pb ions, except for Pb... 2+ In addition, it also contains Pb ions with different valences. As ions and Th ions also contain ions with different valences.

[0482] In the optical glass of the first embodiment, the relative partial dispersion PC,t satisfies the following formula [2-2].

[0483] PC,t≥0.5711+0.004667×νd···[2-2]

[0484] The relative partial dispersion PC,t more preferably satisfies the following equation [2-3], and even more preferably satisfies it in the order of the following equations [2-4], [2-5], [2-6], [2-7] and [2-8].

[0485] PC,t≥0.5731+0.004667×νd···[2-3]

[0486] PC,t≥0.5751+0.004667×νd···[2-4]

[0487] PC,t≥0.5771+0.004667×νd···[2-5]

[0488] PC,t≥0.5791+0.004667×νd···[2-6]

[0489] PC,t≥0.5811+0.004667×νd···[2-7]

[0490] PC,t≥0.5831+0.004667×νd···[2-8]

[0491] By making the relative partial dispersion PC,t satisfy the above formula, the optical element made of the optical glass of the third-1 embodiment can well compensate for chromatic aberration over a wide wavelength range.

[0492] The optical glass of the 3-1 embodiment satisfies one or more of the following (I) to (IV).

[0493] (I)Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The value is below 0.85.

[0494] (II)Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The value is below 0.97.

[0495] Li + Na + Mg 2+ and Ca 2+ Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +Mg 2++Ca 2+ ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The value is above 0.75.

[0496] (III)B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The value is above 0.46.

[0497] (IV)Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ [B] is above 0.75 3+ and Li + Total content and Si 4+ Na + and K + The total content of cation ratio [(B 3+ +Li + ) / (Si 4+ +Na + +K + The value is above 0.31.

[0498] That is, in the optical glass of the third-1st embodiment, under the case of (I) described above, Li + Na + and K + Total content and Si4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The cation ratio can be set to 0.85 or less. In the case of (I) above, the upper limit of this cation ratio can also be set to 0.80, 0.75, 0.70, 0.65, 0.60 or 0.55. In addition, the lower limit of this cation ratio is preferably 0.10, and more preferably in the order of 0.15, 0.20, 0.25, 0.30, 0.35 and 0.40. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and improving chemical durability, it is preferable to make the cation ratio within the above range.

[0499] In the optical glass of the 3-1 embodiment, under the case of (II) described above, Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The cation ratio can be set to 0.97 or less. In the case of (II) above, the upper limit of this cation ratio can also be set to 0.85, 0.80, 0.75, 0.70, 0.65, 0.60 or 0.55. In addition, the lower limit of this cation ratio is preferably 0.10, and more preferably in the order of 0.15, 0.20, 0.25, 0.30, 0.35 and 0.40. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and improving chemical durability, it is preferable to make the cation ratio within the above range.

[0500] Furthermore, in the optical glass of the 3-1 embodiment, under the case of (II) described above, Li + Na + Mg 2+ and Ca 2+ Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +Mg 2++Ca 2 + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The cation ratio can be set to 0.75 or higher. In the case of (II) above, the lower limit of this cation ratio can also be set to 0.77, 0.79, 0.81, 0.83, 0.85, 0.87 or 0.89. The upper limit of this cation ratio is preferably 1, and more preferably in the order of 0.99, 0.98 and 0.95. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and improving the formability by reducing the viscosity of the molten glass, it is preferable to make the cation ratio within the above range.

[0501] In the optical glass of the 3-1 embodiment, under the case of (III) described above, B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The cation ratio can be set to 0.46 or higher. In the case of (III) above, the lower limit of this cation ratio can also be set to 0.50, 0.51, 0.53, 0.55, 0.57 or 0.59. In addition, the cation ratio is preferably less than 1, and its upper limit is more preferably in the order of 0.90, 0.85, 0.80, 0.75, 0.70 and 0.65. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, it is preferable to make the cation ratio within the above range. If the cation ratio is too small, there is a risk of a decrease in the relative partial dispersion PC,t. If the cation ratio is too large, there is a risk of a decrease in the chemical durability of the glass.

[0502] In the optical glass of the 3-1 embodiment, under the case described in (IV) above, Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K +) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The cation ratio can be set to 0.75 or higher. In the case described in (IV) above, the lower limit of this cation ratio can also be set to 0.80, 0.85, or 0.90. Furthermore, the upper limit of this cation ratio is preferably 1.00, and more preferably in the order of 0.98, 0.96, and 0.94. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and improving the formability by reducing the viscosity of the molten glass, it is preferable to make the cation ratio within the above range. If the cation ratio is too small, there is a risk of a decrease in the relative partial dispersion PC,t. If the cation ratio is too large, the thermal stability of the glass decreases, and there is a risk of a decrease in the refractive index nd.

[0503] In the optical glass of the 3-1 embodiment, under the case described in (IV) above, B 3+ and Li + Total content and Si 4+ Na + and K + The total content of cation ratio [(B 3+ +Li + ) / (Si 4+ +Na + +K + The cation ratio can be set to 0.31 or higher. The lower limit of this cation ratio can also be set to 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 1.10, or 1.20. The upper limit of this cation ratio is preferably 10, and more preferably in the order of 9, 8, 7, 6, 5, 4, 3, 2, and 1.8. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, this cation ratio is preferably within the above range.

[0504] Regarding the content and ratio of glass components other than those described above in the optical glass of Embodiment 3-1, non-limiting examples are shown below.

[0505] The optical glass in embodiment 3-1 preferably contains Si. 4+ B 3+ Zr 4+ and Nb 5+ As a component of glass.

[0506] In the optical glass of embodiment 3-1, Si 4+The lower limit of the content is preferably 5%, and more preferably in the order of 7%, 9%, 11%, 13%, 15%, 17%, 19%, and 21%. Additionally, Si... 4+ The upper limit of the Si content is preferably 50%, and more preferably in the order of 40%, 35%, 32%, 30%, 28%, 26%, and 24%. 4+ It is a network-forming component of glass. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and improving chemical durability, Si is preferred. 4+ The content is set within the above range. Si 4+ When the content of Si is too low, the relative partial dispersion PC,t in the infrared wavelength region decreases, and there is a risk of reduced thermal stability and chemical durability of the glass. 4+ Excessive content of certain substances may lead to reduced solubility of the glass, as well as increased viscosity of the molten glass, resulting in poor formability.

[0507] In the optical glass of embodiment 3-1, B 3+ The lower limit of the content is preferably 10%, and more preferably in the order of 15%, 20%, 25%, 28%, 30%, and 32%. Additionally, B... 3+ The upper limit of its content is preferably 60%, and more preferably in the order of 55%, 50%, 45%, 40%, 38%, and 36%. 3+ It is a network-forming component of the glass. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, B is preferred. 3+ The content of B is set within the above range. 3+ When the content is too low, the relative partial dispersion PC,t in the infrared wavelength region decreases, and there is a risk of reduced thermal stability of the glass. 3+ Excessive content of certain substances may reduce the chemical durability of the glass.

[0508] In the optical glass of the 3-1 embodiment, Zr 4+ The lower limit of the content is preferably 0.1%, and more preferably in the order of 1%, 2%, 2.5%, 3%, 3.5%, 4%, and 4.5%. Additionally, Zr... 4+ The upper limit of the content is preferably 20%, and more preferably in the order of 15%, 10%, 8%, 6%, and 5%. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and improving chemical durability, Zr is preferred. 4+ The content of Zr is set within the above range. 4+ When the content is too low, there is a risk of reduced chemical durability. 4+ When the content is too high, there is a risk of an increase in the liquid phase temperature LT, and there is also a risk of reduced stability during reheating.

[0509] In the optical glass of embodiment 3-1, Nb 5+ The lower limit of the content is preferably 0.1%, and more preferably in the order of 1%, 3%, 5%, 7%, 7.5%, and 8%. Additionally, Nb... 5+ The upper limit of the content is preferably 30%, and more preferably in the order of 20%, 15%, 12%, 11.5%, 11%, 10.5%, and 10%. This is achieved by using Nb... 5+ By setting the content within the above range, high dispersibility can be maintained while suppressing the decrease in relative partial dispersion PC,t in the infrared wavelength region. 5+ When the content is too low, there is a risk that high dispersion cannot be maintained. (Nb) 5+ When the content is too high, there is a risk of a decrease in the relative partial dispersion PC,t in the infrared wavelength region.

[0510] The optical glass in embodiment 3-1 preferably contains a material selected from Li. + Na + and K + One or more of the following are used as glass components. The optical glass of embodiment 3-1 more preferably contains Li. + And Na + .

[0511] In the glass of embodiment 3-1, Li + The lower limit of the content is preferably 0%, and more preferably in the order of 5%, 10%, and 15%. Additionally, Li... + The upper limit of the content is preferably 50%, and more preferably in the order of 40%, 30%, and 25%. Li + It is a component that helps reduce the viscosity of glass. Among alkali metals, it has a greater effect on improving the relative partial dispersion PC,t in the infrared wavelength region. + Excessive content of [Li] poses a risk of reduced stability upon reheating. Additionally, [Li] + If the content is too low, there is a risk of increased viscosity in the glass.

[0512] In the glass of embodiment 3-1, Na + The lower limit of the content is preferably 0%, and more preferably in the order of 2%, 4%, 6%, and 8%. Additionally, Na... + The upper limit of the content of Na is preferably 50%, and more preferably in the order of 40%, 30%, 25%, 20%, 15%, and 10%. + With Li + Similarly, it is a component that helps reduce the viscosity of glass. Na + Excessive Na content may lead to decreased stability upon reheating. +If the content is too low, there is a risk of increased viscosity in the glass.

[0513] In the optical glass of embodiment 3-1, K + The upper limit of the content is preferably 50%, and more preferably in the order of 40%, 30%, 25%, 20%, 15%, 10%, and 5%. Additionally, K... + The lower limit of the content is preferably 0%, and more preferably in the order of 1%, 2%, and 3%. K + The content can also be 0%. K + It has the effect of lowering the liquidus temperature and improving the thermal stability of glass. On the other hand, K + As the content of K increases, chemical durability, weather resistance, and stability upon reheating decrease. Therefore, K + The content of [specific component] is preferably within the range described above.

[0514] In the optical glass of embodiment 3-1, Li + Na + and K + Total content [Li + +Na + +K + The lower limit of [Li] is preferably 1%, and more preferably in the order of 5%, 10%, 15%, 20%, and 25%. Additionally, the total content [Li] + +Na + +K + The upper limit of ] is preferably 60%, and more preferably in the order of 50%, 40%, 35%, and 30%. From the viewpoint of suppressing the decrease in stability during reheating, it is preferable to set the total content within the above range.

[0515] In the optical glass of embodiment 3-1, Al 3+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 5%, 2%, and 1%. Additionally, Al... 3+ The lower limit of the content is preferably 0%, and more preferably in the order of 0.1%, 0.2%, and 0.3%. Al 3+ The content can also be 0%. Al 3+ It has the function of suppressing phase separation of glass by containing an appropriate amount. On the other hand, from the viewpoint of maintaining the thermal stability of glass, it is preferable to use Al. 3+ The content is set within the range mentioned above.

[0516] In the optical glass of embodiment 3-1, P 5+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 5%, and 3%. Additionally, P... 5+The lower limit of the content is preferably 0.1%, and more preferably in the order of 0.5%, 0.8%, and 1%. 5+ The content can also be 0%. By using P... 5+ Setting the content within the above range can maintain the thermal stability of the glass.

[0517] In the optical glass of the 3-1 embodiment, Cs + The upper limit of the content is preferably 20%, and more preferably in the order of 15%, 10%, and 5%. Cs + The lower limit of the content of Cs is preferably 0%. + The content can also be 0%.

[0518] Cs + It improves the thermal stability of glass, but increasing its content poses a risk of reduced chemical durability and weather resistance. Therefore, Cs + The content of [specific component] is preferably within the range described above.

[0519] In the optical glass of embodiment 3-1, Mg 2+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 5%, 4%, 3%, 2%, and 1%. Additionally, Mg... 2+ The lower limit of Mg content is preferably 0%. 2+ The content can also be 0%.

[0520] Mg 2+ It is the component of alkaline earth metals that enhances the relative partial dispersion PC,t in the infrared wavelength region. However, Mg 2+ When the content of Mg increases, high dispersion is impaired, and there is a risk of reduced thermal stability and devitrification resistance of the glass. Therefore, Mg 2+ The content of [specific component] is preferably within the range described above.

[0521] In the optical glass of embodiment 3-1, Ca 2+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 5%, 4%, 3%, 2%, and 1%. Additionally, Ca... 2+ The lower limit of the content of Ca is preferably 0%. 2+ The content can also be 0%.

[0522] Ca 2+ It is the component of alkaline earth metals that enhances the relative partial dispersion PC,t in the infrared wavelength region. However, Ca 2+ When the content of Ca increases, high dispersion is impaired, and there is a risk of reduced thermal stability and devitrification resistance of the glass. Therefore, Ca 2+ The content of [specific component] is preferably within the range described above.

[0523] In the optical glass of the 3-1 embodiment, Sr 2+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 5%, 4%, 3%, 2%, and 1%. Additionally, Sr... 2+ The lower limit of the content of Sr is preferably 0%. 2+ The content can also be 0%.

[0524] Sr 2+ It is a component in alkaline earth metals that increases the refractive index. However, Sr... 2+ When the content of Sr increases, high dispersion is impaired, and there is a risk of a decrease in the relative partial dispersion PC,t in the infrared wavelength region. Therefore, Sr 2+ The content of [specific component] is preferably within the range described above.

[0525] In the optical glass of embodiment 3-1, Ba 2+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 9%, 8%, 7%, 6%, 5%, 4%, and 3%. Ba 2+ The lower limit of the content is preferably 0%, and more preferably in the order of 0.5%, 1.0%, and 1.5%. Ba 2+ The content can also be 0%.

[0526] Ba 2+ It is a component that increases the refractive index and also lowers the liquidus temperature, thus improving the thermal stability of the glass. However, Ba... 2+ Excessive content of Ba impairs high dispersion and poses a risk of reduced relative partial dispersion (PC,t) in the infrared wavelength region. Additionally, Ba... 2+ When the content of Ba is too low, the refractive index nd decreases, and there is a risk of reduced thermal stability and devitrification resistance of the glass. Therefore, Ba 2+ The content of [specific component] is preferably within the range described above.

[0527] In the optical glass of embodiment 3-1, Zn 2+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 5%, 4%, 3%, 2%, and 1%. Additionally, Zn... 2+ The lower limit of the content is preferably 0%, and more preferably in the order of 0.1%, 0.5%, and 0.7%. Zn 2+ The content can also be 0%.

[0528] Zn 2+ It is a glass component that improves the thermal stability of glass. However, Zn 2+ Excessive Zn content poses a risk of increased specific gravity and a potential decrease in relative partial dispersion (PC,t) in the infrared wavelength region. Therefore, from the perspective of improving the thermal stability of glass and maintaining desired optical constants, Zn...2+ The content of [specific component] is preferably within the range described above.

[0529] In the optical glass of embodiment 3-1, La 3+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 5%, 4%, and 3%. Additionally, La... 3+ The lower limit of the content is preferably 0%, and more preferably in the order of 1% and 2%. 3+ The content can also be 0%. This can be achieved by introducing a certain amount of La... 3+ This can increase the refractive index nd. However, La 3+ When the content of La is too high, the thermal stability of the glass decreases, and the glass is prone to devitrification during manufacturing. In addition, there is a risk of damage to high dispersion, specifically a decrease in the relative partial dispersion (PC,t) in the infrared wavelength region. Therefore, La... 3+ The content of [specific component] is preferably within the range described above.

[0530] In the glass of embodiment 3-1, Gd 3+ The content of Gd is preferably below 2%. 3+ The lower limit of the content of Gd is preferably 0%. 3+ Excessive Gd content reduces the thermal stability of the glass. Additionally, Gd... 3+ Excessive Gd content increases the specific gravity of the glass, which is undesirable. Furthermore, it poses a risk of increased raw material costs. Therefore, from the perspective of maintaining good thermal stability of the glass while suppressing the increase in specific gravity, Gd... 3+ The content of [specific component] is preferably within the range described above.

[0531] In the glass of embodiment 3-1, Y 3+ The upper limit of the content is preferably 20%, and more preferably in the order of 10%, 5%, 4%, and 3%. Additionally, Y... 3+ The lower limit of the content of Y is preferably 0%, and more preferably in the order of 1% and 2%. 3+ The content can also be 0%.

[0532] By importing a certain amount of Y 3+ This can increase the refractive index nd. However, Y 3+ When the content of Y is too high, the thermal stability of the glass decreases, and the glass is prone to devitrification during manufacturing. In addition, there is a risk of damage to high dispersion. Therefore, from the perspective of suppressing the decrease in the thermal stability of the glass, Y... 3+ The content of [specific component] is preferably within the range described above.

[0533] In the optical glass of embodiment 3-1, Ti 4+The upper limit of the content is preferably 20%, and more preferably in the order of 15%, 10%, 8%, 6%, and 4%. Additionally, Ti... 4+ The lower limit of the content of Ti is preferably 0%, and more preferably in the order of 1%, 2%, and 3%. 4+ The content can also be 0%. By using Ti... 4+ By setting the content within the above range, the desired optical constant can be achieved, and the increase in specific gravity can be suppressed.

[0534] In the optical glass of embodiment 3-1, Ta 5+ The upper limit of the content is preferably 20%, and more preferably in the order of 15%, 10%, 9%, 8%, and 6%. Additionally, Ta... 5+ The lower limit of its content is preferably 0%, and more preferably in the order of 1%, 2%, 3%, and 4%. 5+ The content can also be 0%.

[0535] Ta 5+ It is a component that imparts high refractive index and low dispersion to glass, and improves the relative partial dispersion PC,t in the infrared wavelength region. On the other hand, Ta 5+ Increased content of [a specific ingredient] leads to higher raw material costs. Furthermore, there is a risk of its proportion increasing. Therefore, Ta [is necessary / requires further information]. 5+ The content of [specific component] is preferably within the range described above.

[0536] In the optical glass of embodiment 3-1, W 6+ The upper limit of its content is preferably 20%, and more preferably in the order of 15%, 10%, 8%, 6%, 4%, 2%, 1%, 0.5%, and 0.1%. 6+ The lower limit of its content is preferably 0%. 6+ The content can also be 0%. From the viewpoints of improving transmittance, suppressing the decrease in relative partial dispersion PC,t in the infrared wavelength region, and reducing specific gravity, it is preferable to use W. 6+ The content is set within the range mentioned above.

[0537] In the optical glass of embodiment 3-1, Bi 3+ The upper limit of the content is preferably 20%, and more preferably in the order of 15%, 10%, 8%, and 6%. Additionally, Bi... 3+ The lower limit of the content is preferably 0%, and more preferably in the order of 1%, 2%, 3%, 4%, and 5%. 3+ The content can also be 0%. From the viewpoint of increasing transmittance and reducing specific gravity, and also from the viewpoint of reducing damage to platinum manufacturing equipment, it is preferable to use Bi... 3+ The content is set within the range mentioned above.

[0538] In the glass of embodiment 3-1, Sc 3+ The content of is preferably 2% or less. Additionally, Sc 3+ The lower limit of its content is preferably 0%.

[0539] In the glass of embodiment 3-1, Hf 4+ The content of Hf is preferably below 2%. 4+ The lower limit of its content is preferably 0%.

[0540] Sc 3+ Hf 4+ It has the effect of improving the dispersion of glass, but it is an expensive component. Therefore, Sc 3+ Hf 4+ The preferred content of each is within the range described above.

[0541] In the glass of embodiment 3-1, Lu 3+ The content of [specific component] is preferably 2% or less. Additionally, Lu [is also present]. 3+ The lower limit of its content is preferably 0%.

[0542] Lu 3+ It has the effect of improving the dispersion of glass, but due to its large molecular weight, it is also a glass component that increases the specific gravity of glass. Therefore, Lu 3+ The content of [specific component] is preferably within the range described above.

[0543] In the glass of embodiment 3-1, Ge 4+ The content of [specific component] is preferably 2% or less. Additionally, Ge [specific component]... 4+ The lower limit of its content is preferably 0%.

[0544] Ge 4+ Ge has the effect of improving the dispersion of glass, but it is a very expensive component in commonly used glass compositions. Therefore, from the perspective of reducing the manufacturing cost of glass, Ge... 4+ The content of [specific component] is preferably within the range described above.

[0545] In the glass of embodiment 3-1, Yb 3+ The content of Yb is preferably below 2%. 3+ The lower limit of its content is preferably 0%.

[0546] with La 3+ Gd 3+ Y 3+ In comparison, Yb 3+ The large molecular weight of Yb increases the specific gravity of the glass. Additionally, Yb... 3+ When the content of Yb is too high, the thermal stability of the glass decreases. From the perspective of preventing a decrease in the thermal stability of the glass and inhibiting an increase in specific gravity, Yb... 3+The content of [specific component] is preferably within the range described above.

[0547] In the glass of embodiment 3-1, the upper limit of the respective contents of Cu ions and Ag ions is preferably 1%, and more preferably in the order of 0.5%, 0.2%, 0.1%, 0.05%, and 0.03%. Furthermore, the lower limit of the respective contents of Cu ions and Ag ions is preferably 0%. From the viewpoint of suppressing glass coloration, the respective contents of Cu ions and Ag ions are preferably within the above ranges. Cu ions and Ag ions each contain ions with different valences.

[0548] In the glass of embodiment 3-1, Nb 5+ and Ti 4+ Total content and Nb 5+ Ti 4+ W 6+ and Bi 3+ The total content of cation ratio [(Nb 5+ +Ti 4+ ) / (Nb 5+ +Ti 4+ +W 6+ +Bi 3+ The lower limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.6, 0.7, 0.8, 0.9, and 0.95. The upper limit of the cation ratio is preferably 1, and more preferably in the order of 0.99, 0.98, and 0.97. From the viewpoint of suppressing the reduction of the relative partial dispersion PC,t in the infrared wavelength region, the cation ratio is preferably within the above range.

[0549] In the optical glass of embodiment 3-1, Si 4+ and B 3+ Total content [Si] 4+ +B 3+ The lower limit of the total content is preferably 20%, and more preferably in the order of 25%, 30%, 35%, 40%, 45%, 50%, 52%, 54%, and 56%. Furthermore, the upper limit of this total content is preferably 80%, and more preferably in the order of 75%, 70%, 65%, and 60%. By setting the total content within the above range, the relative partial dispersion PC,t in the infrared wavelength region can be improved, and the thermal stability of the glass can be maintained. If the total content is too low, the relative partial dispersion PC,t in the infrared wavelength region decreases, and there is a risk that the thermal stability and chemical durability of the glass cannot be maintained. If the total content is too high, there is a risk that the viscosity of the molten glass increases, resulting in poor formability. Additionally, there is a risk of a decrease in the refractive index.

[0550] In the optical glass of embodiment 3-1, Si 4+ B 3+ and Al 3+Total content [Si] 4+ +B 3+ +Al 3+ The lower limit of the total content is preferably 20%, and more preferably in the order of 25%, 30%, 35%, 40%, 45%, 50%, 52%, 54%, and 56%. Furthermore, the upper limit of this total content is preferably 80%, and more preferably in the order of 75%, 70%, 65%, and 60%. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, maintaining the thermal stability of the glass, and its stability upon reheating, it is preferable that the total content is within the above-mentioned range.

[0551] In the optical glass of embodiment 3-1, Li + The content of Li + Na + and K + The total content of cation ratio [Li + / (Li + +Na + +K + The upper limit of the cation ratio is preferably 1, and more preferably in the order of 0.95, 0.90, 0.85, 0.80, and 0.75. Furthermore, the lower limit of this cation ratio is preferably 0, and more preferably in the order of 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, and 0.65. From the viewpoint of suppressing the decrease in stability upon reheating, it is preferable that the cation ratio is within the above-mentioned range.

[0552] In the optical glass of embodiment 3-1, Na + The content of Li + Na + and K + The total content of cations [Na] + / (Li + +Na + +K + The upper limit of the cation ratio is preferably 1, and more preferably in the order of 0.90, 0.80, 0.70, 0.60, 0.50, 0.40, and 0.35. Furthermore, the lower limit of this cation ratio is preferably 0, and more preferably in the order of 0.05, 0.10, 0.15, 0.20, and 0.25. The cation ratio can be 0. From the viewpoint of suppressing the decrease in stability upon reheating, it is preferable that the cation ratio is within the above-mentioned range.

[0553] In the optical glass of embodiment 3-1, K + The content of Li + Na + and K +The total content of cation ratio [K] + / (Li + +Na + +K + The upper limit of the cation ratio is preferably 1, and more preferably in the order of 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.60, 0.55, 0.50, 0.45, 0.40, 0.35, 0.30, and 0.25. Furthermore, the lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.05, 0.10, and 0.15. The cation ratio can be 0. From the viewpoint of suppressing the decrease in stability upon reheating, it is preferable that the cation ratio is within the above-mentioned range.

[0554] In the optical glass of embodiment 3-1, Mg 2+ Ca 2+ 、Sr 2+ And Ba 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The upper limit of the total content is preferably 20%, and more preferably in the order of 15%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, and 3%. The lower limit of the total content is preferably 0%, and more preferably in the order of 0.3%, 0.6%, 0.9%, 1.0%, 1.2%, 1.5%, 1.7%, and 1.9%. The total content can also be 0%. When the total content is too high, the high dispersion is impaired, and there is a risk of a decrease in the relative partial dispersion PC,t in the infrared wavelength region. In addition, when the total content is too low, the refractive index nd decreases, and there is a risk of a decrease in the thermal stability and devitrification resistance of the glass. Therefore, the total content is preferably within the above range.

[0555] In the optical glass of embodiment 3-1, Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+The upper limit of the total content is preferably 20%, and more preferably in the order of 15%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, and 3%. The lower limit of the total content is preferably 0%, and more preferably in the order of 0.3%, 0.6%, 0.9%, 1.0%, 1.2%, 1.5%, 1.7%, and 1.9%. The total content can also be 0%. When the total content is too high, the high dispersion is impaired, and there is a risk of a decrease in the relative partial dispersion PC,t in the infrared wavelength region. In addition, when the total content is too low, the refractive index nd decreases, and there is a risk of a decrease in the thermal stability and devitrification resistance of the glass. Therefore, the total content is preferably within the above range.

[0556] In the glass of embodiment 3-1, La 3+ Gd 3+ and Y 3+ Total content [La 3+ +Gd 3+ +Y 3+ The upper limit of the total content is preferably 20%, and more preferably in the order of 10%, 5%, 4%, 3%, 2%, and 1%. The lower limit of the total content is preferably 0%. From the viewpoint of suppressing the decrease in the thermal stability of the glass and preventing the decrease in the relative partial dispersion PC,t in the infrared wavelength region, it is preferable to make the total content within the above range.

[0557] In the optical glass of embodiment 3-1, Nb 5+ and Zr 4+ Total content [Nb] 5+ +Zr 4+ The upper limit of the total content is preferably 30%, and more preferably in the order of 25%, 20%, 18%, 16%, and 15%. Furthermore, the lower limit of this total content is preferably 5%, and more preferably in the order of 7%, 9%, 10%, 11%, and 12%. From the viewpoint of minimizing the reduction of the relative partial dispersion PC,t in the infrared wavelength region without compromising high dispersibility, it is preferable that the total content be within the above-mentioned range.

[0558] In the optical glass of embodiment 3-1, Ta 5+ and Zr 4+ Total content [Ta 5+ +Zr 4+The upper limit of the total content is preferably 20.0%, and more preferably in the order of 15.0%, 12.0%, 10.0%, 9.5%, 9.0%, 8.5%, 8.0%, 7.5%, 7.0%, 6.5%, 6.0%, 5.5%, and 5.0%. Furthermore, the lower limit of this total content is preferably 1.0%, and more preferably in the order of 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, and 4.5%. From the viewpoint of maintaining the thermal stability of the glass, it is preferable that the total content is within the above range. If the total content is too low, there is a risk of reduced chemical durability of the glass. If the total content is too high, there is a risk of reduced thermal stability of the glass and increased raw material costs.

[0559] In the optical glass of embodiment 3-1, Nb 5+ The content of Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Nb] 5+ / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The upper limit of the cation ratio is preferably 1, and more preferably in the order of 0.99, 0.98, 0.97, 0.96, 0.95, 0.94, 0.93, 0.92, and 0.91. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.5, 0.6, 0.7, 0.8, and 0.9. The cation ratio can be 1. From the viewpoint of maintaining a high refractive index, it is preferable that the cation ratio is within the above-mentioned range.

[0560] In the optical glass of embodiment 3-1, Ta 5+ The content of Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Ta 5+ / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The upper limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.4, 0.3, 0.2, and 0.1. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.03, 0.05, and 0.07. The cation ratio can be 0. From the viewpoint of suppressing the increase in raw material costs, it is preferable to make the cation ratio within the above range.

[0561] In the optical glass of embodiment 3-1, Ti 4+ The content of Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Ti 4+ / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The upper limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.4, 0.3, 0.2, and 0.1. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.03, 0.05, and 0.07. The cation ratio can be 0. From the viewpoint of maintaining high dispersivity and suppressing the increase of relative partial dispersion Pg,F in the visible short wavelength region, it is preferable that the cation ratio is within the above-mentioned range.

[0562] In the optical glass of embodiment 3-1, Nb 5+ Zr 4+ Ti 4+ Ta 5+ W 6+ and Bi 3+ Total content [Nb] 5+ +Zr 4 + +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The lower limit of [ ] is preferably 5.0%, and more preferably in the order of 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, and 13%. Furthermore, the upper limit of this total content is preferably 20%, and more preferably in the order of 19%, 18%, 17%, 16%, and 15%. From the viewpoint of increasing the refractive index nd and adjusting the Abbe number νd, it is preferable that the total content is within the above-mentioned range.

[0563] In the optical glass of embodiment 3-1, Nb 5+ The content of Nb 5+ Zr 4+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Nb] 5+ / (Nb 5+ +Zr 4+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The upper limit of the cation ratio is preferably 0.9, and more preferably in the order of 0.8, 0.75, and 0.7. The lower limit of the cation ratio is preferably 0.1, and more preferably in the order of 0.2, 0.3, 0.4, and 0.45. From the viewpoint of maintaining high dispersibility, it is preferable that the cation ratio is within the above-mentioned range.

[0564] In the optical glass of the 3-1 embodiment, Zr 4+ The content of Nb 5+ Zr 4+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Zr 4+ / (Nb 5+ +Zr 4+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The upper limit of the cation ratio is preferably 0.9, and more preferably in the order of 0.8, 0.7, 0.6, 0.55, 0.5, 0.45, and 0.4. The lower limit of the cation ratio is preferably 0.01, and more preferably in the order of 0.10, 0.15, 0.20, 0.25, and 0.30. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and maintaining high dispersibility, the cation ratio is preferably within the above-mentioned range.

[0565] In the optical glass of embodiment 3-1, Ta 5+ The content of Nb 5+ Zr 4+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Ta 5+ / (Nb 5+ +Zr 4+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+The upper limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.4, 0.3, 0.2, and 0.1. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.03, 0.05, and 0.07. The cation ratio can be 0. From the viewpoint of suppressing the increase in raw material costs, it is preferable to make the cation ratio within the above range.

[0566] In the optical glass of embodiment 3-1, Ti 4+ The content of Nb 5+ Zr 4+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Ti 4+ / (Nb 5+ +Zr 4+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The upper limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.4, 0.3, 0.2, and 0.1. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.03, 0.05, and 0.07. The cation ratio can be 0. From the viewpoint of maintaining high dispersivity and suppressing the increase of relative partial dispersion Pg,F in the visible short wavelength region, it is preferable that the cation ratio is within the above-mentioned range.

[0567] In the glass of embodiment 3-1, Mg 2+ Ca 2+ 、Sr 2+ And Ba 2+ Total content and Si 4+ and B 3+ The total content of cations [(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ) / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.4, 0.3, 0.2, 0.1, and 0.08. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.01, 0.02, and 0.03. The cation ratio can be 0. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and improving chemical durability, it is preferable that the cation ratio is within the above-mentioned range.

[0568] In the glass of embodiment 3-1, Mg 2+ Ca 2+ 、Sr 2+Ba 2+ and Zn 2+ Total content and Si 4+ and B 3+ The total content of cations [(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ ) / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.4, 0.3, 0.2, 0.1, and 0.08. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.01, 0.02, and 0.03. The cation ratio can be 0. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and improving chemical durability, it is preferable that the cation ratio is within the above-mentioned range.

[0569] In the optical glass of embodiment 3-1, Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ ) / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 1.50, and more preferably in the order of 1.40, 1.30, 1.20, 1.10, 1.00, 0.90, 0.80, 0.70, 0.60, and 0.55. Furthermore, the lower limit of this cation ratio is preferably 0.10, and more preferably in the order of 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, and 0.45. From the viewpoint of improving the relative partial dispersion (PC,t) in the infrared wavelength region and improving chemical durability, it is preferable that the cation ratio is within the above-mentioned range.

[0570] In the glass of embodiment 3-1, La 3+ Gd 3+ and Y 3+ Total content and Si 4+ and B3+ The total content of cation ratio [(La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.4, 0.3, 0.2, 0.1, and 0.08. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.01, 0.02, and 0.03. The cation ratio can be 0. From the viewpoint of suppressing the decrease in the thermal stability of the glass, it is preferable that the cation ratio is within the above-mentioned range.

[0571] In the glass of embodiment 3-1, Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ Total content and Si 4+ and B 3+ The total content of cation ratio [(Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ ) / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 0.50, and more preferably in the order of 0.40, 0.35, 0.30, 0.25, 0.20, and 0.18. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.02, 0.04, 0.06, 0.08, 0.10, and 0.12. From the viewpoint of maintaining a high refractive index and a desired Abbe number νd, it is preferable that the cation ratio is within the above-mentioned range.

[0572] In the glass of embodiment 3-1, Mg 2+ Ca 2+ 、Sr 2+ And Ba 2+ Total content and Li + Na + and K + The total content of cations [(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ) / (Li + +Na + +K +The upper limit of the cation ratio is preferably 0.6, and more preferably in the order of 0.5, 0.4, 0.3, 0.2, and 0.1. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.02, 0.04, and 0.06. The cation ratio can be 0. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and improving the formability by reducing the viscosity of the molten glass, it is preferable to make the cation ratio within the above range.

[0573] In the glass of embodiment 3-1, Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ Total content and Li + Na + and K + The total content of cations [(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ ) / (Li + +Na + +K + The upper limit of the cation ratio is preferably 0.6, and more preferably in the order of 0.5, 0.4, 0.3, 0.2, and 0.1. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.02, 0.04, and 0.06. The cation ratio can be 0. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and improving the formability by reducing the viscosity of the molten glass, it is preferable to make the cation ratio within the above range.

[0574] In the glass of embodiment 3-1, La 3+ Gd 3+ and Y 3+ Total content and Li + Na + and K + The total content of cation ratio [(La 3+ +Gd 3+ +Y 3+ ) / (Li + +Na + +K + The upper limit of the cation ratio is preferably 0.5, and more preferably in the order of 0.4, 0.3, and 0.2. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.01, 0.03, and 0.05. The cation ratio can be 0. From the viewpoint of suppressing the decrease in the thermal stability of the glass, it is preferable to make the cation ratio within the above range.

[0575] In the glass of embodiment 3-1, Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ Total content and Li + Na + and K + The total content of cation ratio [(Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ ) / (Li + +Na + +K + The upper limit of the cation ratio is preferably 0.60, and more preferably in the order of 0.55, 0.50, 0.45, and 0.40. The lower limit of the cation ratio is preferably 0.05, and more preferably in the order of 0.10, 0.15, 0.17, 0.19, 0.21, 0.23, and 0.25. From the viewpoint of maintaining a high refractive index, improving the solubility of the glass, and reducing the viscosity of the molten glass to improve formability, the cation ratio is preferably within the above-mentioned range.

[0576] In the glass of embodiment 3-1, Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ And Ba 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The upper limit of the cation ratio is preferably 1, and more preferably in the order of 0.99, 0.98, 0.97, 0.96, 0.95, and 0.94. The lower limit of the cation ratio is preferably 0.50, and more preferably in the order of 0.55, 0.60, 0.65, 0.70, and 0.75. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and improving the formability by reducing the viscosity of the molten glass, the cation ratio is preferably within the above-mentioned range.

[0577] In the glass of embodiment 3-1, La 3+ Gd 3+ and Y 3+ Total content and Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [(La 3+ +Gd 3+ +Y 3+ ) / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The upper limit of the cation ratio is preferably 1, and more preferably in the order of 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.1. The lower limit of the cation ratio is preferably 0, and more preferably in the order of 0.01, 0.02, 0.03, 0.04, and 0.05. The cation ratio can be 0. From the viewpoint of suppressing the decrease in the thermal stability of the glass and maintaining a high refractive index, it is preferable that the cation ratio is within the above-mentioned range.

[0578] In the optical glass of embodiment 3-1, B 3+ The content of Nb 5+ Zr 4+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [B] 3+ / (Nb 5+ +Zr 4+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The upper limit of the cation ratio is preferably 7.0, and more preferably in the order of 6.0, 5.5, 5.0, 4.5, 4.0, 3.5, and 3.0. Furthermore, the lower limit of this cation ratio is preferably 1.0, and more preferably in the order of 1.2, 1.4, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, and 2.2. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, it is preferable that the cation ratio is within the above-mentioned range.

[0579] In the optical glass of the 3-1 embodiment, Zr 4+ The content of Nb 5+ Ti 4+ Ta 5+ W 6+ Bi3+ Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [Zr 4+ / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The lower limit of the cation ratio is preferably 0.17, and more preferably in the order of 0.20, 0.25, 0.30, 0.35, 0.37, 0.39, and 0.40. Furthermore, the upper limit of the cation ratio is preferably 2.00, and more preferably in the order of 1.80, 1.60, 1.40, 1.20, 1.00, 0.80, and 0.60. From the viewpoint of improving chemical durability, increasing the refractive index nd, and maintaining high dispersion, the cation ratio is preferably within the above range. If the cation ratio is too small, there is a risk of a decrease in the refractive index nd, and there is also a risk of a decrease in the chemical durability of the glass. If the cation ratio is too large, there is a risk of an increase in the liquidus temperature LT, and there is also a risk of a decrease in stability upon reheating.

[0580] In the optical glass of the 3-1 embodiment, Zr 4+ and Ta 5+ Total content and Nb 5+ Ti 4+ W 6+ Bi 3+ Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Zr 4+ +Ta 5+ ) / (Nb 5+ +Ti 4+ +W 6+ +Bi 3+ +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+The lower limit of the cation ratio is preferably 0.25, and more preferably in the order of 0.30, 0.35, 0.37, 0.39, and 0.40. Furthermore, the upper limit of the cation ratio is preferably 3.10, and more preferably in the order of 2.80, 2.60, 2.40, 2.20, 2.00, 1.80, 1.60, 1.40, 1.20, 1.00, 0.80, 0.60, and 0.55. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the refractive index nd, maintaining high dispersion, and maintaining the chemical durability of the glass, the cation ratio is preferably within the above range. If the cation ratio is too small, there is a risk of a decrease in the refractive index nd, and there is also a risk of a decrease in the chemical durability of the glass. If the cation ratio is too large, there is a risk of a decrease in the thermal stability of the glass.

[0581] The glass in the preferred embodiment 3-1 is mainly composed of the above-mentioned glass composition, namely Si. 4+ B 3+ Zr 4+ 、Nb 5+ Li + Na + K + Al 3+ P 5+ Cs + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ Zn 2+ La 3+ Gd 3+ Y 3+ Ti 4+ Ta 5+ W 6+ Bi 3+ ,Sc 3+ Hf 4+ Lu 3 + 、Ge 4+ and Yb 3+ Composition. The total content of the above-mentioned glass components is preferably 95% or more, more preferably 98% or more, even more preferably 99% or more, and particularly preferably 99.5% or more.

[0582] The optical glass in embodiment 3-1 is an oxide glass containing O 2- As an anionic component. O 2- The preferred content is 90-100% anion, more preferably 95-100% anion.

[0583] The optical glass in embodiment 3-1 may contain F -As an anionic component. F - The preferred content is 0-10% anion, more preferably 0-5% anion.

[0584] The optical glass of embodiment 3-1 may contain O-removal components. 2- and F - Other than O, it is used as an anionic component. 2- and F - Other anionic components, such as Cl, can be used as examples. - ,Br - I - However, Cl - ,Br - I - All of these components readily volatilize during the glass melting process. As these components volatilize, problems arise such as changes in glass properties, reduced glass homogeneity, and significant wear and tear on melting equipment. Therefore, the Cl- content is preferably less than 5% anion, more preferably less than 3% anion, even more preferably less than 1% anion, particularly preferably less than 0.5% anion, and even more preferably less than 0.25% anion. Furthermore, the total Br- and I- content is preferably less than 5% anion, more preferably less than 3% anion, even more preferably less than 1% anion, particularly preferably less than 0.5% anion, even more preferably less than 0.1% anion, and even more preferably 0% anion.

[0585] In the optical glass of embodiment 3-1, F - Cl - ,Br - and I - Total content [F] - +Cl - +Br - +I - The upper limit of the total content is preferably 5% anions, and more preferably in the order of 3% anions, 1% anions, 0.5% anions, and 0.1% anions. The lower limit of the total content is 0% anions. The total content can be 0% anions. As these components volatilize, problems such as changes in glass properties, reduced glass homogeneity, and significant consumption of melting equipment will occur. Therefore, the total content is preferably within the above range.

[0586] The glass in the third-first embodiment is preferably composed of the glass composition described above, but may contain other components to the extent that it does not impair the effects of the present invention. Furthermore, the presence of unavoidable impurities is not excluded in the present invention.

[0587] In addition to the components mentioned above, the optical glass may also contain small amounts of Sb. 3+The clarifying agent is used as a clarifying agent. The total amount of the clarifying agent (additional amount) is preferably 0% or more and less than 1%, more preferably 0% or more and less than 0.9%, 0% or more and less than 0.8%, 0% or more and less than 0.7%, 0% or more and less than 0.6%, 0% or more and less than 0.5%, 0% or more and less than 0.4%, 0% or more and less than 0.3%, 0% or more and less than 0.2%, 0% or more and less than 0.1%, 0% or more and less than 0.05%, or 0% or more and less than 0.03%.

[0588] Additional addition refers to the value obtained by expressing the amount of clarifying agent added as a molar percentage when the total content of all cationic components other than clarifying agent is set to 100%.

[0589] Furthermore, the aforementioned optical glass can achieve high transmittance across a wide range of the visible light spectrum. To fully utilize this advantage, it is preferable to avoid containing coloring elements. Examples of coloring elements include Co, Ni, Fe, Cr, Eu, Nd, Er, and V. Preferably, all elements are below 100 ppm by mass, more preferably 0 to 80 ppm by mass, even more preferably 0 to 50 ppm by mass, and particularly preferably substantially absent.

[0590] Ga, Te, Tb, etc. are components that do not need to be introduced and are also expensive components. Therefore, the content of Ga2O3, TeO2, and TbO2, expressed in mass %, is preferably 0 to 0.1%, more preferably 0 to 0.05%, further preferably 0 to 0.01%, even more preferably 0 to 0.005%, even more preferably 0 to 0.001%, and particularly preferably substantially not contained.

[0591] (Glass properties)

[0592] <Abbe number νd>

[0593] In the optical glass of the 3-1 embodiment, the Abbe number νd is preferably 30 to 60, but can also be set to 32 to 50, 34 to 45, 36 to 40 or 37 to 39.

[0594] The Abbe number νd can be set to a desired value by appropriately adjusting the content of each glass component. This will relatively reduce the component with the Abbe number νd, i.e., the high dispersion component, to Nb. 5+ Ti 4+ Zr 4+ W 6+ Bi 3+ Ta 5+ On the other hand, it will relatively increase the Abbe number νd component, that is, the low dispersion component is Si. 4+ B 3+ Li + Na+ K + La 3+ Ba 2+ Ca 2+ 、Sr 2+ wait.

[0595] <Refractive index nd>

[0596] In the optical glass of the 3-1 embodiment, the refractive index nd is preferably 1.50 to 1.80, but may also be 1.60 to 1.70, 1.63 to 1.69, or 1.66 to 1.68.

[0597] The refractive index nd can be set to a desired value by appropriately adjusting the content of each glass component. The component that has the effect of relatively increasing the refractive index nd (the high-refractive-index component) is Nb. 5+ Ti 4+ Zr 4+ Ta 5+ La 3+ On the other hand, the component that has the effect of relatively reducing the refractive index (nd) (the refractive index-lowering component) is Si. 4+ B 3+ Li + Na + K + wait.

[0598] <Relative partial dispersion Pg,F>

[0599] In the optical glass of the third-first embodiment, the upper limit of the relative partial dispersion Pg,F in the visible short wavelength region is preferably 0.5900, and more preferably in the order of 0.5850, 0.5820, 0.5780, 0.5770, 0.5760, and 0.5750. By making the relative partial dispersion Pg,F within the above range, an optical glass suitable for compensating for higher-order chromatic aberrations can be obtained. On the other hand, the lower limit of the relative partial dispersion Pg,F is not particularly limited, and is generally 0.5600, preferably 0.5650.

[0600] Furthermore, in the optical glass of the 3-1 embodiment, the relative partial dispersion Pg,F preferably satisfies the following formula [1-1].

[0601] Pg,F≤0.6463-0.001802×νd···[1-1]

[0602] The relative partial dispersion Pg,F more preferably satisfies the following equation [1-2], and even more preferably satisfies it in the order of the following equations [1-3], [1-4], [1-5], and [1-6].

[0603] Pg,F≤0.6458-0.001802×νd···[1-2]

[0604] Pg,F≤0.6453-0.001802×νd···[1-3]

[0605] Pg,F≤0.6448-0.001802×νd···[1-4]

[0606] Pg,F≤0.6446-0.001802×νd···[1-5]

[0607] Pg,F≤0.6443-0.001802×νd···[1-6]

[0608] For an optical element made of the optical glass of the 3-1 embodiment, from the viewpoint of effectively compensating for chromatic aberration over a wide wavelength range, the relative partial dispersion Pg,F preferably satisfies the above formula.

[0609] In the optical glass of the third-1 embodiment, the upper limit of ΔPg,F is preferably -0.0020, and more preferably in the order of -0.0025, -0.0030, -0.0035, -0.0037, and -0.0040. On the other hand, the lower limit of ΔPg,F is not particularly limited, and is generally -0.0100, preferably -0.0080. By making ΔPg,F within the above range, optical glass suitable for compensating for higher-order chromatic aberrations can be obtained.

[0610] <Relative Partial Dispersion PC,t>

[0611] In the optical glass of the third-first embodiment, the lower limit of the relative partial dispersion PC,t in the infrared wavelength region is preferably 0.7200, and more preferably in the order of 0.7300, 0.7400, 0.7450, 0.7500, 0.7550, 0.7560, 0.7570, 0.7580, 0.7590, and 0.7600. By making the relative partial dispersion PC,t fall within the above range, optical glass suitable for compensating for higher-order chromatic aberrations can be obtained. On the other hand, the upper limit of the relative partial dispersion PC,t is not particularly limited, and is generally 0.8500, preferably 0.8400, and more preferably in the order of 0.8300, 0.8200, 0.8100, and 0.8000.

[0612] In the optical glass of the third-1 embodiment, the lower limit of ΔPC,t is preferably 0.0200, and more preferably in the order of 0.0250, 0.0270, 0.0290, 0.0310, 0.0330, 0.0350, and 0.0370. On the other hand, the upper limit of ΔPC,t is not particularly limited, and is generally 0.0900, preferably 0.0800. By making ΔPC,t within the above range, optical glass suitable for compensating for higher-order chromatic aberrations can be obtained.

[0613] The relative partial dispersion PC,t can be set to a desired value by appropriately adjusting the content of each glass component. The component that has the effect of relatively improving the relative partial dispersion PC,t is Si. 4+ B 3+ Al 3+ Li + On the other hand, the component that has the effect of relatively reducing the relative partial dispersion PC,t is Sr. 2+ Ba 2+ Zn 2+ La 3+ Ti 4+ 、Nb 5+ W 6+ wait.

[0614] <ΔPg,F and ΔPC,t>

[0615] In the optical glass of the 3-1 embodiment, ΔPg,F and ΔPC,t preferably satisfy the following (i) or (ii).

[0616] (i) When ΔPg,F is greater than -0.0037, ΔPC,t ≥ 2.875 × ΔPg,F + 0.031.

[0617] (ii) When ΔPg,F is below -0.0037, ΔPC,t ≥ 4.750 × ΔPg,F + 0.038.

[0618] (i) In the optical glass of the third-1 embodiment, when ΔPg,F is greater than -0.0037, it is preferable to satisfy the following formula (A1) in the following order (A2), (A3), (A4), and (A5), which is even more preferable.

[0619] ΔPC,t≥2.875×ΔPg,F+0.031···(A1)

[0620] ΔPC,t≥2.875×ΔPg,F+0.035···(A2)

[0621] ΔPC,t≥2.875×ΔPg,F+0.037···(A3)

[0622] ΔPC,t≥2.875×ΔPg,F+0.039···(A4)

[0623] ΔPC,t≥2.875×ΔPg,F+0.041···(A5)

[0624] (ii) In the optical glass of the third-1 embodiment, when ΔPg,F is -0.0037 or less, it is preferable to satisfy the following formula (B1), and it is even more preferable to satisfy it in the order of the following formula (B2), the following formula (B3), the following formula (B4), and the following formula (B5).

[0625] ΔPC,t≥4.750×ΔPg,F+0.038···(B1)

[0626] ΔPC,t≥4.750×ΔPg,F+0.042···(B2)

[0627] ΔPC,t≥4.750×ΔPg,F+0.044···(B3)

[0628] ΔPC,t≥4.750×ΔPg,F+0.046···(B4)

[0629] ΔPC,t≥4.750×ΔPg,F+0.048···(B5)

[0630] In the optical glass of the 3-1 embodiment, the glass properties other than those described above may be the same as those of the 1-1 embodiment.

[0631] The manufacturing of the optical glass and optical components in the 3-1 embodiment can be the same as in the 1-1 embodiment.

[0632] Implementation Method 3-2

[0633] In the oxide optical glass of embodiment 3-2

[0634] Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ Total content [Nb] 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The figure is above 6.5%.

[0635] B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B]3+ / (Si 4+ +B 3+ The value is above 0.41 and below 1.

[0636] Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The value is above 0.55.

[0637] Zr 4+ The content of Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Zr 4+ / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The value is above 0.4.

[0638] Si 4+ B 3+ Li + Na + K + and Zr 4+ Total content and Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [(Si 4+ +B 3+ +Li + +Na + +K + +Zr 4+) / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The value is above 8.6.

[0639] The oxide optical glass is substantially free of Pb and As.

[0640] The oxide optical glass satisfies one or more of the following conditions (I) to (IV).

[0641] (I)Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The value is below 0.85.

[0642] (II)Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The value is below 0.97.

[0643] Li + Na + Mg 2+ and Ca 2+ Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +Mg 2+ +Ca 2+ ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr2+ +Ba 2+ +Zn 2+ The value is above 0.75.

[0644] (III)B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The value is above 0.46.

[0645] (IV)Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ [B] is above 0.75 3+ and Li + Total content and Si 4+ Na + and K + The total content of cation ratio [(B 3+ +Li + ) / (Si 4+ +Na + +K + The value is above 0.31.

[0646] In the optical glass of the third-2nd embodiment, Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ Total content [Nb] 5+ +Ti 4+ +Ta 5 + +W 6+ +Bi 3+The content is 6.5% or more. The lower limit of this total content is preferably 7%, 7.5%, 8%, and 8.5% in that order. Furthermore, the upper limit of this total content is preferably 30%, and further preferably 20%, 15%, 12%, 11.5%, 11%, 10.5%, and 10% in that order. By keeping the total content within the above range, a high refractive index and a desired Abbe number νd can be maintained.

[0647] In the optical glass of the third-2nd embodiment, B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The cation ratio is 0.41 or higher and lower than 1. The lower limit of this cation ratio is preferably 0.46, and more preferably in the order of 0.50, 0.51, 0.53, 0.55, 0.57, and 0.59. Furthermore, the upper limit of this cation ratio is preferably 0.90, and more preferably in the order of 0.85, 0.80, 0.75, 0.70, and 0.65. By setting the cation ratio within the above range, the relative partial dispersion (PC,t) in the infrared wavelength region can be improved. If the cation ratio is too small, there is a risk of a decrease in the relative partial dispersion (PC,t). If the cation ratio is too large, there is a risk of a decrease in the chemical durability of the glass.

[0648] In the optical glass of the third-2nd embodiment, Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2 + Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+The cation ratio is 0.55 or higher. The lower limit of this cation ratio is preferably 0.75, and more preferably in the order of 0.80, 0.85, and 0.90. Furthermore, the upper limit of this cation ratio is preferably 1.00, and more preferably in the order of 0.98, 0.96, and 0.94. By setting the cation ratio within the above range, the relative partial dispersion (PC,t) in the infrared wavelength region can be improved, the solubility of the glass can be improved, and the viscosity of the molten glass can be reduced, thereby improving formability. If the cation ratio is too small, there is a risk of a decrease in the relative partial dispersion (PC,t). If the cation ratio is too large, the thermal stability of the glass decreases, and there is a risk of a decrease in the refractive index (nd).

[0649] In the optical glass of the third-2nd embodiment, Zr 4+ The content of Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Zr 4+ / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The cation ratio is 0.4 or higher. The lower limit of this cation ratio is preferably 0.42, and more preferably in the order of 0.44, 0.46, 0.48, and 0.50. The upper limit of this cation ratio is preferably 1, and more preferably in the order of 0.9, 0.8, 0.7, 0.65, 0.6, and 0.55. By setting the cation ratio within the above range, the relative partial dispersion PC,t in the infrared wavelength region can be improved, while maintaining high dispersibility.

[0650] In the optical glass of the 3-2 embodiment, Si 4+ B 3+ Li + Na + K + and Zr 4+ Total content and Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [(Si 4+ +B 3+ +Li + +Na + +K + +Zr 4+ ) / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi3 + The cation ratio is 8.6 or higher. The lower limit of this cation ratio is preferably 8.8, and more preferably in the order of 9.0, 9.2, 9.4, 9.6, and 9.8. The upper limit of this cation ratio is preferably 20, and more preferably in the order of 18, 16, 14, 13, 12, and 11. By setting the cation ratio to the above range, the relative partial dispersion PC,t in the infrared wavelength region can be improved, and the Abbe number can be adjusted.

[0651] The optical glass of embodiment 3-2 is substantially free of Pb and As, which are components with potential environmental burden. That is, the content of each Pb ion and As ion is 0%. Furthermore, Th, like Pb and As, is a component with potential environmental burden. Therefore, the content of Th ions is preferably 0 to 0.1%, and can be 0 to 0.05% or 0 to 0.01%. The content of Th ions is preferably 0%. That is, it is preferable that it is substantially free of Th. It should be noted that Pb ions, except for Pb... 2+ In addition, it also contains Pb ions with different valences. As ions and Th ions also contain ions with different valences.

[0652] The optical glass of the third-2 embodiment satisfies one or more of the following (I) to (IV).

[0653] (I)Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The value is below 0.85.

[0654] (II)Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The value is below 0.97.

[0655] Li + Na + Mg 2+ and Ca 2+ Total content and Li + Na+ K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +Mg 2+ +Ca 2+ ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The value is above 0.75.

[0656] (III)B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The value is above 0.46.

[0657] (IV)Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The value is above 0.75.

[0658] B 3+ and Li + Total content and Si 4+ Na + and K + The total content of cation ratio [(B 3++Li + ) / (Si 4+ +Na + +K + The value is above 0.31.

[0659] That is, in the optical glass of the 3-2 embodiments, the above-described (I) case, Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The cation ratio can be set to 0.85 or less. In the case of (I) above, the upper limit of this cation ratio can also be set to 0.80, 0.75, 0.70, 0.65, 0.60 or 0.55. In addition, the lower limit of this cation ratio is preferably 0.10, and more preferably in the order of 0.15, 0.20, 0.25, 0.30, 0.35 and 0.40. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and improving chemical durability, it is preferable to make the cation ratio within the above range.

[0660] In the optical glass of the third-2nd embodiment, under the case of (II) described above, Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The cation ratio can be set to 0.97 or less. In the case of (II) above, the upper limit of this cation ratio can also be set to 0.85, 0.80, 0.75, 0.70, 0.65, 0.60 or 0.55. In addition, the lower limit of this cation ratio is preferably 0.10, and more preferably in the order of 0.15, 0.20, 0.25, 0.30, 0.35 and 0.40. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and improving chemical durability, it is preferable to make the cation ratio within the above range.

[0661] Furthermore, in the optical glass of the third-2nd embodiment, in the case of (II) described above, Li + Na + Mg 2+ and Ca 2+Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +Mg 2+ +Ca 2 + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The cation ratio can be set to 0.75 or higher. In the case of (II) above, the lower limit of this cation ratio can also be set to 0.77, 0.79, 0.81, 0.83, 0.85, 0.87 or 0.89. The upper limit of this cation ratio is preferably 1.00, and more preferably in the order of 0.99, 0.98 and 0.95. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and improving the formability by reducing the viscosity of the molten glass, it is preferable to make the cation ratio within the above range.

[0662] In the optical glass of the third-2nd embodiment, under the case of (III) described above, B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The cation ratio can be set to 0.46 or higher. In the case of (III) above, the lower limit of this cation ratio can also be set to 0.50, 0.51, 0.53, 0.55, 0.57 or 0.59. In addition, the cation ratio is preferably less than 1, and its upper limit is more preferably in the order of 0.90, 0.85, 0.80, 0.75, 0.70 and 0.65. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, it is preferable to make the cation ratio within the above range. If the cation ratio is too small, there is a risk of a decrease in the relative partial dispersion PC,t. If the cation ratio is too large, there is a risk of a decrease in the chemical durability of the glass.

[0663] In the optical glass of the third-2nd embodiment, under the case described in (IV) above, Li + Na + and K +Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The cation ratio can be set to 0.75 or higher. In the case described in (IV) above, the lower limit of this cation ratio can also be set to 0.80, 0.85, or 0.90. Furthermore, the upper limit of this cation ratio is preferably 1.00, and more preferably in the order of 0.98, 0.96, and 0.94. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and improving the formability by reducing the viscosity of the molten glass, it is preferable to make the cation ratio within the above range. If the cation ratio is too small, there is a risk of a decrease in the relative partial dispersion PC,t. If the cation ratio is too large, the thermal stability of the glass decreases, and there is a risk of a decrease in the refractive index nd.

[0664] In the optical glass of the third-2nd embodiment, under the case described in (IV) above, B 3+ and Li + Total content and Si 4+ Na + and K + The total content of cation ratio [(B 3+ +Li + ) / (Si 4+ +Na + +K + The cation ratio can be set to 0.31 or higher. The lower limit of this cation ratio can also be set to 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 1.10, or 1.20. The upper limit of this cation ratio is preferably 10, and more preferably in the order of 9, 8, 7, 6, 5, 4, 3, 2, and 1.8. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, this cation ratio is preferably within the above range.

[0665] Furthermore, in the optical glass of the third-2nd embodiment, the relative partial dispersion PC,t preferably satisfies the following formula [2-1].

[0666] PC,t≥0.5661+0.004667×νd···[2-1]

[0667] For the relative partial dispersion PC,t, it is more preferable to satisfy the following equation [2-2], and it is even more preferable to satisfy it in the following order [2-3], [2-4], [2-5], [2-6], [2-7] and [2-8].

[0668] PC,t≥0.5711+0.004667×νd···[2-2]

[0669] PC,t≥0.5731+0.004667×νd···[2-3]

[0670] PC,t≥0.5751+0.004667×νd···[2-4]

[0671] PC,t≥0.5771+0.004667×νd···[2-5]

[0672] PC,t≥0.5791+0.004667×νd···[2-6]

[0673] PC,t≥0.5811+0.004667×νd···[2-7]

[0674] PC,t≥0.5831+0.004667×νd···[2-8]

[0675] In an optical element made of the optical glass of the third-2nd embodiment, from the viewpoint of effectively compensating for chromatic aberration over a wide wavelength range, the relative partial dispersion PC,t preferably satisfies the above formula.

[0676] In the optical glass of embodiments 3-2, the content and ratio of glass components other than those described above can be the same as in embodiment 1.

[0677] Furthermore, in the optical glass of the 3-2 embodiment, the glass properties other than those described above can be the same as those of the 3-1 embodiment.

[0678] Furthermore, the manufacturing of the optical glass and optical elements in the 3-2 embodiment can be the same as in the 3-1 embodiment.

[0679] Implementation Method 3-3

[0680] In the oxide optical glass of Embodiment 3-3

[0681] As a component of glass

[0682] Contains Si4+ B 3+ Zr 4+ and Nb 5+ ,

[0683] And contains selected from Li + Na + and K + One or more of them

[0684] The ΔPg,F and ΔPC,t of the oxide optical glass satisfy either (i) or (ii) below.

[0685] (i) When ΔPg,F is greater than -0.0037, ΔPC,t ≥ 2.875 × ΔPg,F + 0.031.

[0686] (ii) When ΔPg,F is below -0.0037, ΔPC,t ≥ 4.750 × ΔPg,F + 0.038.

[0687] The optical glass in embodiment 3-3 contains Si 4+ B 3+ Zr 4+ and Nb 5+ As a component of glass.

[0688] Furthermore, the optical glass in embodiments 3-3 contains materials selected from Li. + Na + and K + One or more of the following are used as glass components. The optical glass of embodiment 3-2 preferably contains Li. + And Na + .

[0689] In the optical glass of the third-3 embodiment, ΔPg,F and ΔPC,t satisfy either of the following (i) or (ii).

[0690] (i) When ΔPg,F is greater than -0.0037, ΔPC,t ≥ 2.875 × ΔPg,F + 0.031.

[0691] (ii) When ΔPg,F is below -0.0037, ΔPC,t ≥ 4.750 × ΔPg,F + 0.038.

[0692] (i) In the optical glass of the third-3rd embodiment, when ΔPg,F is greater than -0.0037, it is preferable to satisfy the following formula (A1), and it is even more preferable to satisfy it in the order of the following formula (A2), the following formula (A3), the following formula (A4), and the following formula (A5).

[0693] ΔPC,t≥2.875×ΔPg,F+0.031···(A1)

[0694] ΔPC,t≥2.875×ΔPg,F+0.035···(A2)

[0695] ΔPC,t≥2.875×ΔPg,F+0.037···(A3)

[0696] ΔPC,t≥2.875×ΔPg,F+0.039···(A4)

[0697] ΔPC,t≥2.875×ΔPg,F+0.041···(A5)

[0698] (ii) In the optical glass of the third-3rd embodiment, when ΔPg,F is -0.0037 or less, it is preferable to satisfy the following formula (B1), and it is even more preferable to satisfy it in the order of the following formula (B2), the following formula (B3), the following formula (B4), and the following formula (B5).

[0699] ΔPC,t≥4.750×ΔPg,F+0.038···(B1)

[0700] ΔPC,t≥4.750×ΔPg,F+0.042···(B2)

[0701] ΔPC,t≥4.750×ΔPg,F+0.044···(B3)

[0702] ΔPC,t≥4.750×ΔPg,F+0.046···(B4)

[0703] ΔPC,t≥4.750×ΔPg,F+0.048···(B5)

[0704] In the optical glass of the third-3rd embodiment, Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ Total content [Nb] 5+ +Ti 4+ +Ta 5 + +W 6+ +Bi 3+ The lower limit of the total content is preferably 6.5%, and more preferably in the order of 7%, 7.5%, 8%, and 8.5%. Furthermore, the upper limit of this total content is preferably 30%, and more preferably in the order of 20%, 15%, 12%, 11.5%, 11%, 10.5%, and 10%. From the viewpoint of maintaining a high refractive index and a desired Abbe number νd, it is preferable that the total content is within the above-mentioned range.

[0705] In the optical glass of the third-3rd embodiment, Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2 + Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The lower limit of the cation ratio is preferably 0.55, and more preferably in the order of 0.75, 0.80, 0.85, and 0.90. Furthermore, the upper limit of the cation ratio is preferably 1.00, and more preferably in the order of 0.98, 0.96, and 0.94. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and improving the formability by reducing the viscosity of the molten glass, the cation ratio is preferably within the above-mentioned range. If the cation ratio is too small, there is a risk of a decrease in the relative partial dispersion PC,t. Furthermore, if the cation ratio is too large, the thermal stability of the glass decreases, and there is a risk of a decrease in the refractive index nd.

[0706] In the optical glass of the third-3rd embodiment, Zr 4+ The content of Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Zr 4+ / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The lower limit of the cation ratio is preferably 0.4, and more preferably in the order of 0.42, 0.44, 0.46, 0.48, and 0.50. The upper limit of the cation ratio is preferably 1, and more preferably in the order of 0.9, 0.8, 0.7, 0.65, 0.6, and 0.55. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and maintaining high dispersibility, it is preferable to make the cation ratio within the above-mentioned range.

[0707] In the optical glass of the third-3rd embodiment, Si 4+ B 3+ Li + Na + K + and Zr 4+ Total content and Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [(Si 4+ +B 3+ +Li + +Na + +K + +Zr 4+ ) / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3 + The lower limit of the cation ratio is preferably 8.6, and more preferably in the order of 8.8, 9.0, 9.2, 9.4, 9.6, and 9.8. The upper limit of the cation ratio is preferably 20, and more preferably in the order of 18, 16, 14, 13, 12, and 11. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and adjusting the Abbe number, the cation ratio is preferably within the above range.

[0708] The optical glass of the third-3 embodiment preferably contains substantially no Pb or As, which are components with potential environmental burden. That is, the content of each Pb ion and As ion is preferably 0%. Furthermore, Th, like Pb and As, is a component with potential environmental burden. Therefore, the content of Th ions is preferably 0 to 0.1%, and can be 0 to 0.05% or 0 to 0.01%. The content of Th ions is preferably 0%. That is, it is preferable to contain substantially no Th. It should be noted that Pb ions, except for Pb... 2+ In addition, it also contains Pb ions with different valences. As ions and Th ions also contain ions with different valences.

[0709] Furthermore, in the optical glass of the third-3rd embodiment, the relative partial dispersion PC,t preferably satisfies the following formula [2-1].

[0710] PC,t≥0.5661+0.004667×νd···[2-1]

[0711] For the relative partial dispersion PC,t, it is more preferable to satisfy the following equation [2-2], and it is even more preferable to satisfy it in the following order [2-3], [2-4], [2-5], [2-6], [2-7] and [2-8].

[0712] PC,t≥0.5711+0.004667×νd···[2-2]

[0713] PC,t≥0.5731+0.004667×νd···[2-3]

[0714] PC,t≥0.5751+0.004667×νd···[2-4]

[0715] PC,t≥0.5771+0.004667×νd···[2-5]

[0716] PC,t≥0.5791+0.004667×νd···[2-6]

[0717] PC,t≥0.5811+0.004667×νd···[2-7]

[0718] PC,t≥0.5831+0.004667×νd···[2-8]

[0719] In an optical element made of the optical glass of the third-third embodiment, from the viewpoint of effectively compensating for chromatic aberration over a wide wavelength range, the relative partial dispersion PC,t preferably satisfies the above formula.

[0720] The optical glass of the third-third embodiment can satisfy one or more of (I) to (IV) as described in detail in the first embodiment.

[0721] In the optical glass of the 3-3 embodiment, the content and ratio of glass components other than those described above can be the same as in the 3-1 embodiment.

[0722] Furthermore, in the optical glass of the 3-3 embodiment, the glass properties other than those described above can be the same as those of the 3-1 embodiment.

[0723] Furthermore, the manufacturing of the optical glass and optical elements in the third-third embodiment can be the same as in the first embodiment.

[0724] Implementation methods 3-4

[0725] In the oxide optical glass of embodiments 3-4

[0726] As a component of glass

[0727] Contains Si 4+ B 3+ Zr 4+ and Nb 5+ ,

[0728] And contains selected from Li + Na + and K + One or more of them

[0729] The oxide optical glass PC,t satisfies the following equation [2-1].

[0730] PC,t≥0.5661+0.004667×νd···[2-1]

[0731] The optical glass in embodiments 3-4 contains Si 4+ B 3+ Zr 4+ and Nb 5+ As a component of glass.

[0732] Furthermore, the optical glass in embodiments 3-4 contains materials selected from Li. + Na + and K + One or more of the following are used as glass components. The optical glass of embodiments 3-4 preferably contains Li. + And Na + .

[0733] In the optical glass of embodiments 3-4, the relative partial dispersion PC,t satisfies the following formula [2-1].

[0734] PC,t≥0.5661+0.004667×νd···[2-1]

[0735] In the optical glass of embodiments 3-4, the relative partial dispersion PC,t preferably satisfies the following formula [2-2], and it is even more preferable that it satisfies the following formulas in the following order [2-3], [2-4], [2-5], [2-6], [2-7] and [2-8].

[0736] PC,t≥0.5711+0.004667×νd···[2-2]

[0737] PC,t≥0.5731+0.004667×νd···[2-3]

[0738] PC,t≥0.5751+0.004667×νd···[2-4]

[0739] PC,t≥0.5771+0.004667×νd···[2-5]

[0740] PC,t≥0.5791+0.004667×νd···[2-6]

[0741] PC,t≥0.5811+0.004667×νd···[2-7]

[0742] PC,t≥0.5831+0.004667×νd···[2-8]

[0743] The method for calculating the relative partial dispersion PC,t is as described in Embodiment 3-1. By making the relative partial dispersion PC,t satisfy the above formula, the optical element made of the optical glass of Embodiments 3-4 can effectively compensate for chromatic aberration over a wide wavelength range.

[0744] In the optical glass of embodiments 3-4, the relative partial dispersion Pg,F preferably satisfies the following formula [1-1].

[0745] Pg,F≤0.6463-0.001802×νd···[1-1]

[0746] In the optical glass of embodiments 3-4, the relative partial dispersion Pg,F more preferably satisfies the following formula [1-2], and even more preferably satisfies it in the order of the following formula [1-3], the following formula [1-4], the following formula [1-5], and the following formula [1-6].

[0747] Pg,F≤0.6458-0.001802×νd···[1-2]

[0748] Pg,F≤0.6453-0.001802×νd···[1-3]

[0749] Pg,F≤0.6448-0.001802×νd···[1-4]

[0750] Pg,F≤0.6446-0.001802×νd···[1-5]

[0751] Pg,F≤0.6443-0.001802×νd···[1-6]

[0752] The method for calculating the relative partial dispersion Pg,F is as described in Embodiment 3-1. By making the relative partial dispersion Pg,F satisfy the above formula, the optical element made of the optical glass of Embodiments 3-4 can effectively compensate for chromatic aberration over a wide wavelength range.

[0753] In the optical glass of embodiments 3-4, Nb 5+ Ti 4+ Ta 5+W 6+ and Bi 3+ Total content [Nb] 5+ +Ti 4+ +Ta 5 + +W 6+ +Bi 3+ The lower limit of the total content is preferably 6.5%, and more preferably in the order of 7%, 7.5%, 8%, and 8.5%. Furthermore, the upper limit of this total content is preferably 30%, and more preferably in the order of 20%, 15%, 12%, 11.5%, 11%, 10.5%, and 10%. From the viewpoint of maintaining a high refractive index and a desired Abbe number νd, it is preferable that the total content is within the above-mentioned range.

[0754] In the optical glass of embodiments 3-4, Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2 + Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The lower limit of the cation ratio is preferably 0.55, and more preferably in the order of 0.75, 0.80, 0.85, and 0.90. Furthermore, the upper limit of the cation ratio is preferably 1.00, and more preferably in the order of 0.98, 0.96, and 0.94. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region, improving the solubility of the glass, and improving the formability by reducing the viscosity of the molten glass, the cation ratio is preferably within the above-mentioned range. If the cation ratio is too small, there is a risk of a decrease in the relative partial dispersion PC,t. Furthermore, if the cation ratio is too large, the thermal stability of the glass decreases, and there is a risk of a decrease in the refractive index nd.

[0755] In the optical glass of embodiments 3-4, Zr 4+ The content of Nb 5+ Ti 4+ Ta5+ W 6+ and Bi 3+ The total content of cation ratio [Zr 4+ / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The lower limit of the cation ratio is preferably 0.4, and more preferably in the order of 0.42, 0.44, 0.46, 0.48, and 0.50. The upper limit of the cation ratio is preferably 1, and more preferably in the order of 0.9, 0.8, 0.7, 0.65, 0.6, and 0.55. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and maintaining high dispersibility, it is preferable to make the cation ratio within the above-mentioned range.

[0756] In the optical glass of embodiments 3-4, Si 4+ B 3+ Li + Na + K + and Zr 4+ Total content and Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [(Si 4+ +B 3+ +Li + +Na + +K + +Zr 4+ ) / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3 + The lower limit of the cation ratio is preferably 8.6, and more preferably in the order of 8.8, 9.0, 9.2, 9.4, 9.6, and 9.8. The upper limit of the cation ratio is preferably 20, and more preferably in the order of 18, 16, 14, 13, 12, and 11. From the viewpoint of improving the relative partial dispersion PC,t in the infrared wavelength region and adjusting the Abbe number, it is preferable to make the cation ratio within the above-mentioned range.

[0757] The optical glass of embodiments 3 and 4 preferably contains substantially no Pb or As, which are components with potential environmental burden. That is, the content of each Pb ion and As ion is preferably 0%. Furthermore, Th, like Pb and As, is a component with potential environmental burden. Therefore, the content of Th ions is preferably 0 to 0.1%, and can be 0 to 0.05% or 0 to 0.01%. The content of Th ions is preferably 0%. That is, it is preferable to contain substantially no Th. It should be noted that Pb ions, except for Pb... 2+ In addition, it also contains Pb ions with different valences. As ions and Th ions also contain ions with different valences.

[0758] The optical glass of embodiments 3-4 can satisfy one or more of (I) to (IV) as detailed in embodiment 3-1.

[0759] In the optical glass of embodiments 3-4, the content and ratio of glass components other than those described above can be the same as in embodiment 3-1.

[0760] Furthermore, in the optical glass of embodiments 3-4, the glass properties other than those described above can be the same as those of embodiment 3-1.

[0761] Furthermore, the manufacturing of the optical glass and optical elements in embodiments 3-4 can be the same as in embodiment 3-1.

[0762] Example

[0763] The present invention will now be described in more detail through embodiments. However, the present invention is not limited to the embodiments shown.

[0764] (Example 1)

[0765] Glass samples with the glass composition shown in the table were prepared according to the following steps, and various evaluations were performed.

[0766] Here, Table 1 expresses the glass composition in mass % and Table 2 expresses the glass composition in cation % %. That is, although the methods of expressing the glass composition are different in Tables 1 and 2, optical glasses with the same sample number refer to the same optical glasses with the same composition. Therefore, Tables 1 and 2 show substantially the same optical glasses and their results.

[0767] It should be noted that in Table 2, the glass composition is expressed as cation percent, and all anionic components are O. 2- That is, the composition of O recorded in Table 2 2- The content of all is 100% anion.

[0768] In addition, the composition expressed as mass % in Table 1 is derived from the composition expressed as cation % in Table 2.

[0769] Manufacturing of optical glass

[0770] First, oxides, hydroxides, carbonates, and nitrates corresponding to the components of the glass are prepared as raw materials. These raw materials are weighed and mixed thoroughly, ensuring the optical glass composition is as shown in Tables 1 and 2. The resulting batch of raw materials is then placed in a platinum crucible and heated at 1350°C–1400°C for 2–4 hours to produce molten glass. The mixture is stirred to achieve homogenization. After clarification, the molten glass is poured into a mold preheated to an appropriate temperature. The poured glass is then heat-treated for 30 minutes at a temperature near its glass transition temperature (Tg), and then naturally cooled to room temperature in the furnace to obtain the glass sample.

[0771] [Confirmation of glass composition]

[0772] The contents of each glass component were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) for the obtained glass samples, and the compositions shown in Tables 1 to 12 were confirmed.

[0773] [Determination of optical properties]

[0774] The obtained glass samples were further annealed near the glass transition temperature Tg for approximately 30 minutes to approximately 2 hours, and then cooled to room temperature in a furnace at a cooling rate of -30°C / hour to obtain annealed samples. For the annealed samples, the refractive index, Abbe number νd, relative partial dispersion Pg,F, deviation ΔPg,F, relative partial dispersion PC,t, deviation ΔPC,t, specific gravity, glass transition temperature Tg, liquidus temperature LT, λ80, and λ5 were measured. The results are shown in Tables 1–12.

[0775] (i) Refractive indices nd, ng, nF, nC, Abbe number νd, relative partial dispersion PC,t, and relative partial dispersion Pg,F

[0776] For the annealed samples mentioned above, the refractive index at the 12 wavelengths shown in Table A was determined by JIS B 7071-1 Method for Determination of Refractive Index of Optical Glass - Part 1: Minimum Deflection Method.

[0777] Next, the refractive indices of each spectral line obtained by measurement were substituted into the Schott dispersion formula specified in Annex B of JIS B 7071-1 Method for Determination of Refractive Index of Optical Glass - Part 1: Method of Least Deflection Angle, and the constants of the Schott dispersion formula were obtained by least squares method. Then, using the Schott dispersion formula with determined constants, the Abbe number νd, the relative partial dispersion PC,t, and the relative partial dispersion Pg,F were calculated.

[0778] [Table A]

[0779] Wavelength (nm) Spectral lines light source 1013.98 T-rays (infrared mercury) Hg 852.11 G-rays (infrared cesium) Cs 706.52 gamma rays (red helium) He 656.27 C-rays (red hydrogen) H 643.85 C' rays (red cadmium) Cd 587.56 D-rays (yellow helium) He 546.07 gamma rays (green mercury) Hg 486.13 F-rays (blue hydrogen) H 479.99 F' rays (blue cadmium) Cd 435.84 Gamma rays (blue mercury) Hg 404.66 h-rays (purple mercury) Hg 365.01 i-rays (ultraviolet mercury) Hg

[0780] Schott dispersion formula: n 2 =a0+a1λ 2 +a2λ -2 +a3λ -4 +a4λ -6 +a5λ -8

[0781] In the formula, n is the refractive index, λ is the wavelength (μm), and a0, a1, a2, a3, a4, and a5 are constants.

[0782] It should be noted that nd refers to the refractive index at a wavelength of 587.56 nm.

[0783] The Abbe number νd is represented using the refractive indices nd, nF, and nC under d-rays, F-rays, and C-rays as shown below.

[0784] νd=(nd-1) / (nF-nC)

[0785] The relative partial dispersion PC,t is represented by the refractive indices nt, nF, and nC under t-rays, F-rays, and C-rays as shown below.

[0786] PC,t = (nC - nt) / (nF - nC)

[0787] The relative partial dispersion Pg,F is represented by the refractive indices ng, nF, and nC under g-rays, F-rays, and C-rays as shown below.

[0788] Pg,F=(ng-nF) / (nF-nC)

[0789] (ii) Deviation ΔPC,t, deviation ΔPg,F

[0790] In a plane where the Abbe number νd is represented by the horizontal axis and the relative partial dispersion PC,t is represented by the vertical axis, the normal PC,t(0) is expressed by the following equation.

[0791] PC,t(0)=0.5461-(0.004667×νd)

[0792] The deviation ΔPC,t of the relative partial dispersion PC,t with respect to the normal is calculated based on the following formula.

[0793] ΔPC,t=PC,t-PC,t(0)

[0794] Furthermore, in a plane where the Abbe number νd is represented by the horizontal axis and the relative partial dispersion Pg,F is represented by the vertical axis, the normal Pg,F(0) is expressed by the following formula.

[0795] Pg,F(0)=0.6483-(0.001802×νd)

[0796] The deviation ΔPg,F of the relative partial dispersion Pg,F with respect to the normal is calculated based on the following formula.

[0797] ΔPg,F=Pg,F-Pg,F(0)

[0798] (iii) Specific gravity

[0799] The specific gravity was determined using the Archimedes method.

[0800] (iv) Glass transition temperature Tg

[0801] The glass transition temperature Tg was determined using a differential scanning calorimeter (DSC3300SA) manufactured by NETZSCH JAPAN at a heating rate of 10 °C / min.

[0802] (v) Liquid phase temperature LT

[0803] The glass was placed in a furnace heated to a given temperature and held for about 2 hours. After cooling, the interior of the glass was observed using an optical microscope with magnification of 40 to 100 times, and the liquidus temperature was determined based on the presence or absence of crystallization.

[0804] (vi)λ80、λ5

[0805] The annealed sample was processed into a 10 mm thick plane with parallel, optically polished surfaces. The spectral transmittance in the wavelength range from 280 nm to 700 nm was measured. The intensity of light incident perpendicularly to one of the optically polished surfaces was defined as intensity A, and the intensity of light exiting from the other surface was defined as intensity B. The spectral transmittance B / A was calculated. The wavelength with a spectral transmittance of 80% was defined as λ80, and the wavelength with a spectral transmittance of 5% was defined as λ5. It should be noted that the spectral transmittance also includes light reflection loss from the sample surface.

[0806] [Chemical durability and water resistance Dw]

[0807] The obtained glass samples were prepared into powdered glass (particle size 425–600 μm). A mass of this powdered glass, equivalent to its specific gravity, was placed in a platinum cage and immersed in a quartz glass round-bottom flask containing 80 mL of pure water (pH = 6.5–7.5). The flask was then treated in a boiling water bath for 60 minutes. The samples were classified and evaluated according to the mass reduction rate (%) as per Table B.

[0808] [Table B]

[0809]

[0810]

[0811] [Chemical durability and acid resistance (Da)]

[0812] The obtained glass samples were made into powder glass (particle size 425–600 μm). A mass of this powder glass with a specific gravity equivalent was placed in a platinum cage and immersed in a quartz glass round-bottom flask containing 80 mL of 0.01 mol / L nitric acid aqueous solution for 60 minutes. The powder glass was classified and evaluated according to the mass reduction rate (%) in Table C.

[0813] [Table C]

[0814] grade Quality reduction (%) 1 Less than 0.20% 2 Above 0.20% and below 0.35% 3 Above 0.35% and below 0.65% 4 Above 0.65% and less than 1.20% 5 1.20% or more but less than 2.20% 6 2.20% or more

[0815] [Chemical durability, resistance to latent damage D] NaOH ]

[0816] The obtained glass sample was processed to a diameter of 43.7 mm (30 cm on both sides). 2 A polished sample, approximately 5 mm thick, was immersed in a 0.01 mol / L NaOH aqueous solution at 50°C for 15 hours after thorough stirring. The mass reduction per unit area was calculated as [mg / (cm²)]. 2 ·15h)] Classify and evaluate according to the levels in Table D.

[0817] [Table D]

[0818] grade <![CDATA[Mass reduction [mg / (cm 2 ·15 h)]]]> 1 Less than 0.02 2 Above 0.02 and below 0.10 3 0.10 or higher and less than 0.20 4 Above 0.20 and below 0.30 5 0.30 and above

[0819] [Chemical durability, resistance to latent damage D] STPP ]

[0820] The obtained glass sample was processed to a diameter of 43.7 mm (30 cm on both sides). 2 A polished sample, approximately 5 mm thick, was prepared and placed in a 0.01 mol / L Na₅P₃O₂ solution at 50°C after thorough stirring. 10 Immerse in (STPP) aqueous solution for 1 hour. At this time, the mass reduction per unit area is [mg / (cm²)]. 2 ·h)] Classify and evaluate according to the levels in Table E.

[0821] [Table E]

[0822] grade <![CDATA[Mass reduction [mg / (cm 2 ·h)]]]> 1 Less than 0.02 2 Above 0.02 and below 0.20 3 Above 0.20 and below 0.40 4 0.40 or higher and less than 0.60 5 0.60 and above

[0823] [Chemical durability, chemical durability D0]

[0824] The obtained glass sample was processed to a diameter of 43.7 mm (30 cm on both sides).2 A polished sample, approximately 5 mm thick, was prepared on both sides. When immersed in pure water at 50°C, pH 7.0 ± 0.2, and thoroughly stirred while passing through and circulating it through an ion exchange resin layer at a rate of 1 L / min, the mass reduction per unit area was

[10] . -3 mg / (cm 2 ·h)] Classify and evaluate according to the levels in Table F.

[0825] [Table F]

[0826] grade <![CDATA[Mass reduction [10 -3 mg / (cm 2 ·h)]]]> 1 Less than 0.4 2 0.4 or higher and less than 5.0 3 5.0 or higher but less than 10.0 4 10.0 or higher but less than 15.0 5 15.0 or above

[0827]

[0828]

[0829]

[0830]

[0831]

[0832]

[0833]

[0834]

[0835]

[0836]

[0837]

[0838]

[0839]

[0840]

[0841]

[0842]

[0843]

[0844]

[0845]

[0846]

[0847]

[0848]

[0849]

[0850]

[0851]

[0852]

[0853]

[0854]

[0855]

[0856]

[0857]

[0858]

[0859]

[0860]

[0861]

[0862]

[0863]

[0864]

[0865]

[0866]

[0867]

[0868]

[0869]

[0870]

[0871]

[0872]

[0873]

[0874]

[0875]

[0876]

[0877]

[0878]

[0879]

[0880]

[0881]

[0882]

[0883]

[0884]

[0885]

[0886]

[0887]

[0888]

[0889]

[0890]

[0891] (Example 2)

[0892] Using the optical glass prepared in Example 1, lens blanks were made by known methods, and the lens blanks were processed by known methods such as polishing to produce various lenses.

[0893] The optical lenses manufactured include various types such as biconvex lenses, biconcave lenses, plano-convex lenses, plano-concave lenses, concave meniscus lenses, and convex meniscus lenses.

[0894] Various lenses, when combined with lenses made of low-dispersion glass with an Abbe number of 65 or higher, such as fluorophosphate glass, can effectively compensate for high-order chromatic aberrations in the infrared region.

[0895] Furthermore, since glass has a low specific gravity, each lens is lighter than a lens of the same optical properties and size, making it suitable for various imaging devices, especially for autofocus imaging devices due to energy-saving considerations. Similarly, prisms were made using the various optical glasses produced in Example 1.

[0896] It should be understood that the embodiments disclosed herein are exemplary in all respects and not restrictive. The scope of the invention is defined by the claims, not by the foregoing description, and is intended to include all modifications in the meaning and scope equivalent to the claims.

[0897] For example, by adjusting the composition described in the specification, an optical glass of one aspect of the present invention can be prepared for the glass composition exemplified above.

[0898] In addition, of course, any combination of two or more items described in the specification as examples or preferred options is possible.

Claims

1. An oxide optical glass, wherein, When expressed as cations%, the cations% is the molar percentage when the total content of all cationic components in the oxide optical glass is set to 100%. Si 4+ The content is 5-50% cationic. B 3+ The content is 10-60% cationic. Zr 4+ The content is 0.1~20% cationic. Nb 5+ The content is 0.1~30% cationic. Sr 2+ The content is less than 4% cations. Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ Total content [Nb] 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The content is above 6.5% cations. Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The value is above 0.

55. Zr 4+ The content of Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Zr 4+ / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The value is between 0.4 and 0.

7. Si 4+ B 3+ Li + Na + K + and Zr 4+ Total content and Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [(Si 4+ +B 3+ +Li + +Na + +K + +Zr 4+ ) / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The value is above 8.

6. Mg 2+ Ca 2+ 、Sr 2+ And Ba 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The percentage of cations is less than 10%. The oxide optical glass is substantially free of Pb and As. The PC, t of the oxide optical glass satisfies the following equation [2-2]: PC, t≥0.5711+0.004667×νd···[2-2], The oxide optical glass satisfies one or more of the following (I) to (III): (I) Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3 + The value is below 0.

85. (II) Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The value is below 0.

97. Li + Na + Mg 2+ and Ca 2+ Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +Mg 2+ +Ca 2+ ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The value is above 0.

75. (III) B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The value is above 0.

46.

2. An oxide optical glass, wherein, When expressed as cations%, the cations% is the molar percentage when the total content of all cationic components in the oxide optical glass is set to 100%. Si 4+ The content is 5-50% cationic. B 3+ The content is 10-60% cationic. Zr 4+ The content is 0.1~20% cationic. Nb 5+ The content is 0.1~30% cationic. Sr 2+ The content is less than 4% cations. Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ Total content [Nb] 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The content is above 6.5% cations. Zr 4+ The content of Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Zr 4+ / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The value is between 0.4 and 0.

7. Si 4+ B 3+ Li + Na + K + and Zr 4+ Total content and Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [(Si 4+ +B 3+ +Li + +Na + +K + +Zr 4+ ) / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The value is above 8.

6. Mg 2+ Ca 2+ 、Sr 2+ And Ba 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The percentage of cations is less than 10%. The oxide optical glass is substantially free of Pb and As. The PC, t of the oxide optical glass satisfies the following equation [2-2]: PC, t≥0.5711+0.004667×νd···[2-2], The oxide optical glass satisfies the following (IV): (IV) Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The value is above 0.

75. B 3+ and Li + Total content and Si 4+ Na + and K + The total content of cation ratio [(B 3+ +Li + ) / (Si 4+ +Na + +K + The value is above 0.

31.

3. An oxide optical glass, wherein, When expressed as cations%, the cations% is the molar percentage when the total content of all cationic components in the oxide optical glass is set to 100%. Si 4+ The content is 5-50% cationic. B 3+ The content is 10-60% cationic. Zr 4+ The content is 0.1~20% cationic. Nb 5+ The content is 0.1~30% cationic. Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ Total content [Nb] 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The content is above 6.5% cations. B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The value is above 0.41 and below 1. Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The value is above 0.

55. Zr 4+ The content of Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Zr 4+ / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The value is above 0.

4. Si 4+ B 3+ Li + Na + K + and Zr 4+ Total content and Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [(Si 4+ +B 3+ +Li + +Na + +K + +Zr 4+ ) / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The value is above 8.

6. Mg 2+ Ca 2+ 、Sr 2+ And Ba 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The percentage of cations is less than 10%. The oxide optical glass is substantially free of Pb and As. The PC, t of the oxide optical glass satisfies the following equation [2-2]: PC, t≥0.5711+0.004667×νd···[2-2], The oxide optical glass satisfies one or more of the following (I) to (II): (I) Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3 + The value is below 0.

85. (II) Li + Na + and K + Total content and Si 4+ and B 3+ The total content of cation ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The value is below 0.

97. Li + Na + Mg 2+ and Ca 2+ Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +Mg 2+ +Ca 2+ ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The value is above 0.

75.

4. An oxide optical glass, wherein, When expressed as cations%, the cations% is the molar percentage when the total content of all cationic components in the oxide optical glass is set to 100%. Si 4+ The content is 5-50% cationic. B 3+ The content is 10-60% cationic. Zr 4+ The content is 0.1~20% cationic. Nb 5+ The content is 0.1~30% cationic. Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ Total content [Nb] 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The content is above 6.5% cations. B 3+ The content of Si 4+ and B 3+ The total content of cation ratio [B] 3+ / (Si 4+ +B 3+ The value is above 0.41 and below 1. Zr 4+ The content of Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [Zr 4+ / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The value is above 0.

4. Si 4+ B 3+ Li + Na + K + and Zr 4+ Total content and Nb 5+ Ti 4+ Ta 5+ W 6+ and Bi 3+ The total content of cation ratio [(Si 4+ +B 3+ +Li + +Na + +K + +Zr 4+ ) / (Nb 5+ +Ti 4+ +Ta 5+ +W 6+ +Bi 3+ The value is above 8.

6. Mg 2+ Ca 2+ 、Sr 2+ And Ba 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The percentage of cations is less than 10%. The oxide optical glass is substantially free of Pb and As. The PC, t of the oxide optical glass satisfies the following equation [2-2]: PC, t≥0.5711+0.004667×νd···[2-2], The oxide optical glass satisfies the following (IV): (IV) Li + Na + and K + Total content and Li + Na + K + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content of cation ratio [(Li + +Na + +K + ) / (Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The value is above 0.

75. B 3+ and Li + Total content and Si 4+ Na + and K + The total content of cation ratio [(B 3+ +Li + ) / (Si 4+ +Na + +K + The value is above 0.

31.

5. The optical glass according to any one of claims 1 to 4, wherein, Total content [Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit is 7% cationic, and / or Total content [Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit is 30% cationic, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The lower limit of )] is 0.75, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The upper limit for )] is 0.98, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.42, and / or Cation ratio [(Si 4＋ +B 3＋ +Li ＋ +Na ＋ +K ＋ +Zr 4＋ ) / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 8.6, and / or Cation ratio [(Si 4＋ +B 3＋ +Li ＋ +Na ＋ +K ＋ +Zr 4＋ ) / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit for )] is 20, and / or The Th ion content is 0~0.01 cation%, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.85, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.10, and / or Cation ratio [(Li ＋ +Na ＋ +Mg 2＋ +Ca 2＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2 ＋ The lower limit of )] is 0.77, and / or Cation ratio [(Li ＋ +Na ＋ +Mg 2＋ +Ca 2＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2 ＋ The upper limit of )] is 0.99, and / or Cation ratio [B] 3＋ / (Si 4＋ +B 3＋ The lower limit of )] is 0.50, and / or Cation ratio [B] 3＋ / (Si 4＋ +B 3＋ The upper limit of )] is 0.90, and / or Cation ratio [(B 3＋ +Li ＋ ) / (Si 4＋ +Na ＋ +K ＋ The lower limit of )] is 0.40, and / or Cation ratio [(B 3＋ +Li ＋ ) / (Si 4＋ +Na ＋ +K ＋ The upper limit of )] is 5, and / or Zr 4＋ The upper limit for its content is 15% cationic, and / or Nb 5＋ The upper limit for its content is 20% cationic, and / or Li ＋ The lower limit for its content is 5% cationic, and / or Li ＋ The upper limit for its content is 40% cationic, and / or Na ＋ The lower limit for its content is 2% cationic, and / or Na ＋ The upper limit for its content is 30% cationic, and / or K ＋ The upper limit for its content is 25% cationic, and / or K ＋ The lower limit of its content is 1% cationic, and / or Total content [Li] ＋ +Na ＋ +K ＋ The lower limit is 1% cation, and / or Total content [Li] ＋ +Na ＋ +K ＋ The upper limit is 50% cationic, and / or Al 3＋ The upper limit for its content is 10% cationic, and / or Al 3＋ The lower limit of its content is 0.1% cationic, and / or P 5＋ The upper limit for its content is 10% cationic, and / or P 5＋ The lower limit of its content is 0.1% cationic, and / or The upper limit for Cs+ content is 5% cationic, and / or The Cs+ content is 0% cationic, and / or Mg 2＋ The upper limit for its content is 10% cationic, and / or Ca 2＋ The upper limit for its content is 10% cationic, and / or Ba 2＋ The upper limit for its content is 20% cationic, and / or Ba 2＋ The lower limit of its content is 0.5% cationic, and / or Zn 2＋ The upper limit for its content is 20% cationic, and / or Zn 2＋ The lower limit of its content is 0.1% cationic, and / or La 3＋ The upper limit for its content is 20% cationic, and / or La 3＋ The lower limit of its content is 1% cationic, and / or Gd 3＋ The content is 2% cationic, and / or Y 3＋ The upper limit for its content is 10% cationic, and / or Y 3＋ The lower limit of its content is 1% cationic, and / or Ti 4＋ The upper limit for its content is 15% cationic, and / or Ti 4＋ The lower limit of its content is 1% cationic, and / or Ta 5＋ The upper limit for its content is 15% cationic, and / or Ta 5＋ The lower limit of its content is 1% cationic, and / or W 6＋ The upper limit for its content is 15% cationic, and / or Bi 3＋ The upper limit for its content is 15% cationic, and / or Bi 3＋ The lower limit of its content is 1% cationic, and / or Sc 3＋ The content is less than 2% cations, and / or Hf 4＋ The content is less than 2% cations, and / or Lu 3＋ The content is less than 2% cations, and / or Ge 4＋ The content is less than 2% cations, and / or Yb 3＋ The content is less than 2% cations, and / or The upper limit for the content of Cu ions and Ag ions is 0.03% cations, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ ) / (Nb 5＋ +Ti 4＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.6, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ ) / (Nb 5＋ +Ti 4＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.99, and / or Total content [Si] 4＋ +B 3＋ The lower limit is 20% cationic, and / or Total content [Si] 4＋ +B 3＋ The upper limit is 80% cationic, and / or Total content [Si] 4＋ +B 3＋ +Al 3＋ The upper limit is 80% cationic, and / or Cation ratio [Li] ＋ / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.95, and / or Cation ratio [Li] ＋ / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.05, and / or Cation ratio [Na] ＋ / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.90, and / or Cation ratio [Na] ＋ / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.05, and / or Cation ratio [K] ＋ / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.95, and / or Cation ratio [K] ＋ / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.05, and / or Total content [Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ The lower limit is 0.3% cationic, and / or Total content [Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The upper limit is 15% cationic, and / or Total content [Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The lower limit is 0.3% cationic, and / or Total content [La] 3＋ +Gd 3＋ +Y 3＋ The upper limit is 10% cationic, and / or Total content [Nb] 5＋ +Zr 4＋ The upper limit is 30% cationic, and / or Total content [Nb] 5＋ +Zr 4＋ The lower limit is 5% cationic, and / or Total content [Ta] 5＋ +Zr 4＋ The upper limit is 15.0% cationic, and / or Total content [Ta] 5＋ +Zr 4＋ The lower limit is 1.0% cations, and / or Cation ratio [Nb] 5＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.99, and / or Cation ratio [Nb] 5＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.5, and / or Cation ratio [Ta] 5＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.5, and / or Cation ratio [Ta] 5＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.03, and / or Cation ratio [Ti 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.5, and / or Cation ratio [Ti 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.03, and / or Total content [Nb] 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit is 5.0% cationic, and / or Total content [Nb] 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit is 20% cationic, and / or Cation ratio [Nb] 5＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.9, and / or Cation ratio [Nb] 5＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.1, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.9, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.01, and / or Cation ratio [Ta] 5＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.5, and / or Cation ratio [Ta] 5＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.03, and / or Cation ratio [Ti 4＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.5, and / or Cation ratio [Ti 4＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.03, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.5, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.01, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.5, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.01, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Si 4＋ +B 3＋ The upper limit for )] is 1.50, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.10, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.5, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.01, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.50, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.02, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ ) / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.6, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ ) / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.02, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.6, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.02, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.5, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.01, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ ) / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.60, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ ) / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.05, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ The upper limit of )] is 0.99, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ The lower limit of )] is 0.50, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.9, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.01, and / or Cation ratio [B] 3＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit for )] is 7.0, and / or Cation ratio [B] 3＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 1.0, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The lower limit of )] is 0.17, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The upper limit for )] is 2.00, and / or Cation ratio [(Zr 4＋ +Ta 5＋ ) / (Nb 5＋ +Ti 4＋ +W 6＋ +Bi 3＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The lower limit of )] is 0.25, and / or Cation ratio [(Zr 4＋ +Ta 5＋ ) / (Nb 5＋ +Ti 4＋ +W 6＋ +Bi 3＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The upper limit of )] is 3.10, and / or Si 4＋ B 3＋ Zr 4＋ 、Nb 5＋ Li ＋ Na ＋ K ＋ Al 3＋ P 5＋ Cs+, Mg 2＋ Ca 2＋ 、Sr 2＋ Ba 2＋ Zn 2＋ La 3＋ Gd 3 ＋ Y 3＋ Ti 4＋ Ta 5＋ W 6＋ Bi 3＋ ,Sc 3＋ Hf 4＋ Lu 3＋ 、Ge 4＋ and Yb 3＋ The total content is over 95% cationic.

6. The optical glass according to any one of claims 1 to 4, wherein, Total content [Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit is 8% cationic, and / or Total content [Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit is 10.5% cationic, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The lower limit of )] is 0.85, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The upper limit of )] is 0.96, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.48, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.6, and / or Cation ratio [(Si 4＋ +B 3＋ +Li ＋ +Na ＋ +K ＋ +Zr 4＋ ) / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 9.6, and / or Cation ratio [(Si 4＋ +B 3＋ +Li ＋ +Na ＋ +K ＋ +Zr 4＋ ) / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 12, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.60, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.35, and / or Cation ratio [(Li ＋ +Na ＋ +Mg 2＋ +Ca 2＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2 ＋ The lower limit of )] is 0.87, and / or Cation ratio [(Li ＋ +Na ＋ +Mg 2＋ +Ca 2＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2 ＋ The upper limit of )] is 0.99, and / or Cation ratio [B] 3＋ / (Si 4＋ +B 3＋ The lower limit of )] is 0.57, and / or Cation ratio [B] 3＋ / (Si 4＋ +B 3＋ The upper limit of )] is 0.70, and / or Cation ratio [(B 3＋ +Li ＋ ) / (Si 4＋ +Na ＋ +K ＋ The lower limit of )] is 1.10, and / or Cation ratio [(B 3＋ +Li ＋ ) / (Si 4＋ +Na ＋ +K ＋ The upper limit of )] is 3, and / or Si 4＋ The lower limit of its content is 19% cationic, and / or Si 4＋ The upper limit for its content is 26% cationic, and / or B 3＋ The lower limit of its content is 30% cationic, and / or B 3＋ The upper limit for its content is 38% cationic, and / or Zr 4＋ The lower limit for its content is 4% cationic, and / or Zr 4＋ The upper limit for its content is 6% cationic, and / or Nb 5＋ The lower limit for its content is 5% cationic, and / or Nb 5＋ The upper limit for its content is 11% cationic, and / or Li ＋ The lower limit for its content is 10% cationic, and / or Li ＋ The upper limit for its content is 30% cationic, and / or Na ＋ The lower limit for its content is 6% cationic, and / or Na ＋ The upper limit for its content is 15% cationic, and / or K ＋ The upper limit for its content is 10% cationic, and / or K ＋ The lower limit for its content is 2% cationic, and / or Total content [Li] ＋ +Na ＋ +K ＋ The lower limit is 1% cation, and / or Total content [Li] ＋ +Na ＋ +K ＋ The upper limit is 35% cationic, and / or Al 3＋ The upper limit for its content is 2% cationic, and / or Al 3＋ The lower limit of its content is 0.2% cationic, and / or P 5＋ The upper limit for its content is 5% cationic, and / or P 5＋ The lower limit of its content is 0.5% cationic, and / or Mg 2＋ The upper limit for its content is 3% cationic, and / or Ca 2＋ The upper limit for its content is 3% cationic, and / or Sr 2＋ The upper limit for its content is 3% cationic, and / or Ba 2＋ The upper limit for its content is 5% cationic, and / or Ba 2＋ The lower limit of its content is 1.0% cationic, and / or Zn 2＋ The upper limit for its content is 3% cationic, and / or Zn 2＋ The lower limit of its content is 0.5% cationic, and / or La 3＋ The upper limit for its content is 5% cationic, and / or La 3＋ The lower limit for its content is 2% cationic, and / or Y 3＋ The upper limit for its content is 4% cationic, and / or Y 3＋ The lower limit for its content is 2% cationic, and / or Ti 4＋ The upper limit for its content is 6% cationic, and / or Ti 4＋ The lower limit for its content is 2% cationic, and / or Ta 5＋ The upper limit for its content is 8% cationic, and / or Ta 5＋ The lower limit for its content is 3% cationic, and / or W 6＋ The upper limit of its content is 1% cationic, and / or Bi 3＋ The upper limit for its content is 8% cationic, and / or Bi 3＋ The lower limit for its content is 4% cationic, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ ) / (Nb 5＋ +Ti 4＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.8, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ ) / (Nb 5＋ +Ti 4＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.98, and / or Total content [Si] 4＋ +B 3＋ The lower limit is 52% cationic, and / or Total content [Si] 4＋ +B 3＋ The upper limit is 65% cationic, and / or Total content [Si] 4＋ +B 3＋ +Al 3＋ The lower limit is 52% cationic, and / or Total content [Si] 4＋ +B 3＋ +Al 3＋ The upper limit is 65% cationic, and / or Cation ratio [Li ＋ / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.80, and / or Cation ratio [Li ＋ / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.60, and / or Cation ratio [Na] ＋ / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.40, and / or Cation ratio [Na] ＋ / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.20, and / or Cation ratio [K] ＋ / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.30, and / or Cation ratio [K] ＋ / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.10, and / or Total content [Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ The upper limit is 5% cationic, and / or Total content [Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ The lower limit is 1.5% cationic, and / or Total content [Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The upper limit is 5% cationic, and / or Total content [Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The lower limit is 1.5% cationic, and / or Total content [La] 3＋ +Gd 3＋ +Y 3＋ The upper limit is 3% cationic, and / or Total content [Nb] 5＋ +Zr 4＋ The upper limit is 16% cationic, and / or Total content [Nb] 5＋ +Zr 4＋ The lower limit is 10% cationic, and / or Total content [Ta] 5＋ +Zr 4＋ The upper limit is 6.0% cationic, and / or Total content [Ta] 5＋ +Zr 4＋ The lower limit is 4.0% cationic, and / or Cation ratio [Nb] 5＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.93, and / or Cation ratio [Nb] 5＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.7, and / or Cation ratio [Ta] 5＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.2, and / or Cation ratio [Ta] 5＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.05, and / or Cation ratio [Ti 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.2, and / or Cation ratio [Ti 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.05, and / or Total content [Nb] 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit is 12% cationic, and / or Total content [Nb] 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit is 17% cationic, and / or Cation ratio [Nb] 5＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.75, and / or Cation ratio [Nb] 5＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.4, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.5, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.20, and / or Cation ratio [Ta] 5＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.2, and / or Cation ratio [Ta] 5＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.05, and / or Cation ratio [Ti 4＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.2, and / or Cation ratio [Ti 4＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.05, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.1, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.02, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.2, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.02, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.60, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.40, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.2, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.02, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.25, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.10, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ ) / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.2, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ ) / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.04, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.2, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.04, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.3, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.03, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ ) / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.50, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ ) / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.21, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ The upper limit of )] is 0.95, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ The lower limit of )] is 0.70, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.3, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.03, and / or Cation ratio [B] 3＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit for )] is 4.0, and / or Cation ratio [B] 3＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 1.8, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The lower limit of )] is 0.35, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The upper limit of )] is 0.80, and / or Cation ratio [(Zr 4＋ +Ta 5＋ ) / (Nb 5＋ +Ti 4＋ +W 6＋ +Bi 3＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The lower limit of )] is 0.35, and / or Cation ratio [(Zr 4＋ +Ta 5＋ ) / (Nb 5＋ +Ti 4＋ +W 6＋ +Bi 3＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The upper limit of )] is 1.00, and / or Si 4＋ B 3＋ Zr 4＋ 、Nb 5＋ Li ＋ Na ＋ K ＋ Al 3＋ P 5＋ Cs+, Mg 2＋ Ca 2＋ 、Sr 2＋ Ba 2＋ Zn 2＋ La 3＋ Gd 3 ＋ Y 3＋ Ti 4＋ Ta 5＋ W 6＋ Bi 3＋ ,Sc 3＋ Hf 4＋ Lu 3＋ 、Ge 4＋ and Yb 3＋ The total content is over 99% cationic.

7. The optical glass according to any one of claims 1 to 4, wherein, Total content [Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit is 8.5% cationic, and / or Total content [Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit is 10% cationic, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The lower limit of )] is 0.90, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The upper limit of )] is 0.94, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.50, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.55, and / or Cation ratio [(Si 4＋ +B 3＋ +Li ＋ +Na ＋ +K ＋ +Zr 4＋ ) / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 9.8, and / or Cation ratio [(Si 4＋ +B 3＋ +Li ＋ +Na ＋ +K ＋ +Zr 4＋ ) / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 11, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.55, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.40, and / or Cation ratio [(Li ＋ +Na ＋ +Mg 2＋ +Ca 2＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2 ＋ The lower limit of )] is 0.89, and / or Cation ratio [(Li ＋ +Na ＋ +Mg 2＋ +Ca 2＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2 ＋ The upper limit of )] is 0.95, and / or Cation ratio [B] 3＋ / (Si 4＋ +B 3＋ The lower limit of )] is 0.59, and / or Cation ratio [B] 3＋ / (Si 4＋ +B 3＋ The upper limit of )] is 0.65, and / or Cation ratio [(B 3＋ +Li ＋ ) / (Si 4＋ +Na ＋ +K ＋ The lower limit of )] is 1.20, and / or Cation ratio [(B 3＋ +Li ＋ ) / (Si 4＋ +Na ＋ +K ＋ The upper limit of )] is 1.8, and / or Si 4＋ The lower limit of its content is 21% cationic, and / or Si 4＋ The upper limit for its content is 24% cationic, and / or B 3＋ The lower limit of its content is 32% cationic, and / or B 3＋ The upper limit for its content is 36% cationic, and / or Zr 4＋ The lower limit of its content is 4.5% cationic, and / or Zr 4＋ The upper limit for its content is 5% cationic, and / or Nb 5＋ The lower limit for its content is 8% cationic, and / or Nb 5＋ The upper limit for its content is 10% cationic, and / or Li ＋ The lower limit of its content is 15% cationic, and / or Li ＋ The upper limit for its content is 25% cationic, and / or Na ＋ The lower limit for its content is 8% cationic, and / or Na ＋ The upper limit for its content is 10% cationic, and / or K ＋ The upper limit for its content is 5% cationic, and / or K ＋ The lower limit for its content is 3% cationic, and / or Total content [Li] ＋ +Na ＋ +K ＋ The lower limit is 25% cationic, and / or Total content [Li] ＋ +Na ＋ +K ＋ The upper limit is 30% cationic, and / or Al 3＋ The upper limit of its content is 1% cationic, and / or Al 3＋ The lower limit of its content is 0.3% cationic, and / or P 5＋ The upper limit for its content is 3% cationic, and / or P 5＋ The lower limit of its content is 1% cationic, and / or Mg 2＋ The upper limit of its content is 1% cationic, and / or Ca 2＋ The upper limit of its content is 1% cationic, and / or Sr 2＋ The upper limit of its content is 1% cationic, and / or Ba 2＋ The upper limit for its content is 3% cationic, and / or Ba 2＋ The lower limit of its content is 1.5% cationic, and / or Zn 2＋ The upper limit of its content is 1% cationic, and / or Zn 2＋ The lower limit of its content is 0.7% cationic, and / or La 3＋ The upper limit for its content is 3% cationic, and / or Y 3＋ The upper limit for its content is 3% cationic, and / or Ti 4＋ The upper limit for its content is 4% cationic, and / or Ti 4＋ The lower limit for its content is 3% cationic, and / or Ta 5＋ The upper limit for its content is 6% cationic, and / or Ta 5＋ The lower limit for its content is 4% cationic, and / or W 6＋ The upper limit of its content is 0.1% cationic, and / or Bi 3＋ The upper limit for its content is 6% cationic, and / or Bi 3＋ The lower limit for its content is 5% cationic, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ ) / (Nb 5＋ +Ti 4＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.95, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ ) / (Nb 5＋ +Ti 4＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.97, and / or Total content [Si] 4＋ +B 3＋ The lower limit is 56% cationic, and / or Total content [Si] 4＋ +B 3＋ The upper limit is 60% cationic, and / or Total content [Si] 4＋ +B 3＋ +Al 3＋ The lower limit is 56% cationic, and / or Total content [Si] 4＋ +B 3＋ +Al 3＋ The upper limit is 60% cationic, and / or Cation ratio [Li ＋ / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.75, and / or Cation ratio [Li ＋ / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.65, and / or Cation ratio [Na] ＋ / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.35, and / or Cation ratio [Na] ＋ / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.25, and / or Cation ratio [K] ＋ / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.25, and / or Cation ratio [K] ＋ / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.15, and / or Total content [Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ The upper limit is 3% cationic, and / or Total content [Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ The lower limit is 1.9% cations, and / or Total content [Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The upper limit is 3% cationic, and / or Total content [Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The lower limit is 1.9% cations, and / or Total content [La] 3＋ +Gd 3＋ +Y 3＋ The upper limit is 1% cationic, and / or Total content [Nb] 5＋ +Zr 4＋ The upper limit is 15% cationic, and / or Total content [Nb] 5＋ +Zr 4＋ The lower limit is 12% cationic, and / or Total content [Ta] 5＋ +Zr 4＋ The upper limit is 5.0% cationic, and / or Total content [Ta] 5＋ +Zr 4＋ The lower limit is 4.5% cationic, and / or Cation ratio [Nb] 5＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.91, and / or Cation ratio [Nb] 5＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.9, and / or Cation ratio [Ta] 5＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.1, and / or Cation ratio [Ta] 5＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.07, and / or Cation ratio [Ti 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.1, and / or Cation ratio [Ti 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.07, and / or Total content [Nb] 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit is 13% cationic, and / or Total content [Nb] 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit is 15% cationic, and / or Cation ratio [Nb] 5＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.7, and / or Cation ratio [Nb] 5＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.45, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.4, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.30, and / or Cation ratio [Ta] 5＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.1, and / or Cation ratio [Ta] 5＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.07, and / or Cation ratio [Ti 4＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.1, and / or Cation ratio [Ti 4＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.07, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.08, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.03, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.08, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.03, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.55, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.45, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.08, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.03, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ ) / (Si 4＋ +B 3＋ The upper limit of )] is 0.18, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ ) / (Si 4＋ +B 3＋ The lower limit of )] is 0.12, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ ) / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.1, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ ) / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.06, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.1, and / or Cation ratio [(Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ ) / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.06, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.2, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.05, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ ) / (Li ＋ +Na ＋ +K ＋ The upper limit of )] is 0.40, and / or Cation ratio [(Nb] 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ ) / (Li ＋ +Na ＋ +K ＋ The lower limit of )] is 0.25, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ The upper limit of )] is 0.94, and / or Cation ratio [(Li ＋ +Na ＋ +K ＋ ) / (Li ＋ +Na ＋ +K ＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ The lower limit of )] is 0.75, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 0.1, and / or Cation ratio [(La 3＋ +Gd 3＋ +Y 3＋ ) / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 0.05, and / or Cation ratio [B] 3＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The upper limit of )] is 3.0, and / or Cation ratio [B] 3＋ / (Nb 5＋ +Zr 4＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ The lower limit of )] is 2.2, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The lower limit of )] is 0.40, and / or Cation ratio [Zr] 4＋ / (Nb 5＋ +Ti 4＋ +Ta 5＋ +W 6＋ +Bi 3＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The upper limit of )] is 0.60, and / or Cation ratio [(Zr 4＋ +Ta 5＋ ) / (Nb 5＋ +Ti 4＋ +W 6＋ +Bi 3＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The lower limit of )] is 0.40, and / or Cation ratio [(Zr 4＋ +Ta 5＋ ) / (Nb 5＋ +Ti 4＋ +W 6＋ +Bi 3＋ +Mg 2＋ +Ca 2＋ +Sr 2＋ +Ba 2＋ +Zn 2＋ The upper limit of )] is 0.55, and / or Si 4＋ B 3＋ Zr 4＋ 、Nb 5＋ Li ＋ Na ＋ K ＋ Al 3＋ P 5＋ Cs+, Mg 2＋ Ca 2＋ 、Sr 2＋ Ba 2＋ Zn 2＋ La 3＋ Gd 3 ＋ Y 3＋ Ti 4＋ Ta 5＋ W 6＋ Bi 3＋ ,Sc 3＋ Hf 4＋ Lu 3＋ 、Ge 4＋ and Yb 3＋ The total content is over 95% cationic.

8. The optical glass according to any one of claims 1 to 4, wherein, O 2- The content of anions is 90-100%.

9. The optical glass according to any one of claims 1 to 4, wherein, O 2- The content of anions is 95-100%.

10. The optical glass according to any one of claims 1 to 4, wherein, Any element in Co, Ni, Fe, Cr, Eu, Nd, Er, V less than 100 ppm by mass, and / or The contents of Ga2O3, TeO2, and TbO2, expressed as mass%, range from 0 to 0.1%.

11. The optical glass according to any one of claims 1 to 4, wherein its Abbe number νd is 30 to 60, and / or The refractive index nd is 1.50~1.80, and / or The optical glass satisfies the following equation [2-3]: PC, t≥0.5731+0.004667×νd ···[2-3], and / or It can be seen that the upper limit of the relative partial dispersion Pg,F in the short wavelength region is 0.5900, and / or For relative partial dispersion Pg, the lower limit of F is 0.5600, and / or The optical glass satisfies the following equation [1-2]: Pg, F≤0.6458-0.001802×νd ···[1-2], and / or The upper limit of ΔPg, F is -0.0020, and / or The lower limit for ΔPg, F is -0.0100, and / or The lower limit of the relative partial dispersion PC, t in the infrared wavelength region is 0.7200, and / or For relative partial dispersion PC, the upper limit of t is 0.8500, and / or The lower limit of ΔPC,t is 0.0200, and / or When ΔPg, F is greater than -0.0037, it satisfies ΔPC, t ≥ 2.875 × ΔPg, F + 0.031, and / or When ΔPg, F is below -0.0037, it satisfies ΔPC, t ≥ 4.750 × ΔPg, F + 0.038, and / or Specific gravity below 4.00, and / or The upper limit of the liquidus temperature LT is 1300℃, and / or The lower limit of the liquidus temperature LT is 1000℃, and / or The lower limit of the glass transition temperature Tg is 400℃, and / or The upper limit of the glass transition temperature Tg is 600℃, and / or λ80 is below 450nm, and / or λ5 is below 400nm, and / or Water resistance Dw is 5 or higher, and / or Acid resistance Da is 5 or higher, and / or Resistance to latent damage (DNaOH) is level 4 or higher, and / or DSTPP resistance to lurking damage is level 4 or higher, and / or Chemical durability D0 is level 4 or above.

12. The optical glass according to any one of claims 1 to 4, wherein, Nb 5+ and Ti 4+ Total content and Nb 5+ Ti 4+ W 6+ and Bi 3+ The total content of cation ratio [(Nb 5+ +Ti 4+ ) / (Nb 5+ +Ti 4+ +W 6+ +Bi 3+ The value is above 0.

5.

13. An optical element made of the optical glass according to any one of claims 1 to 12.

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