Optical glass, optical element blank, glass material for press molding, and optical element

Abstract

Provided are an optical glass, an optical element blank, a glass material for press molding, and an optical element, which have abnormal partial dispersion and stability during reheating. In the optical glass, the molar ratio [F / Al] of the content of F to the content of Al is 2.50 to 15.0, the molar ratio [Ba / P] of the content of Ba to the content of P is 0.100 to 1.20, the molar ratio [P / Al] of the content of P to the content of Al is 0.200 to 2.00, and the molar ratio [O / P] of the content of O to the content of P is 3.05 to 4.20.

Description

Technical Field

[0001] This invention relates to optical glass, optical element blanks, glass materials for pressing and molding, and optical elements. Background Technology

[0002] In recent years, lenses made of low-refractive-index / abnormally partially dispersed glass have become increasingly popular, not only in digital cameras but also in mass-produced cameras such as surveillance cameras, thanks to improved productivity and lower prices. Therefore, there is a growing demand for low-cost, mass-producible glass for such lenses.

[0003] Fluorophosphate glass, which has been widely used in lenses with low refractive index and anomalous partial dispersion, is prone to compositional changes due to the volatilization of its glass components, thus easily developing veins. Furthermore, increasing the refractive index requires the inclusion of rare earth elements, which is expensive and increases the risk of breakage. For example, previous attempts to address the vein problem have focused on reducing the amount of volatile glass components, but such glasses exhibit low stability upon reheating. In particular, fluorine (F) is a component whose composition changes easily due to volatilization, becoming a major cause of vein formation. Therefore, the reduction of F content was investigated, and it was found that fluorophosphate glass with lower F content and higher refractive index tends to show a significant decrease in stability upon reheating.

[0004] Patent Document 1 proposes a fluorophosphate glass with high refractive index, low dispersion, and anomalous partial dispersion. However, the glass in Patent Document 1 suffers from poor stability upon reheating.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2014 / 196523 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The inventors conducted in-depth research and found that in the glass disclosed in Patent Document 1, the stability during reheating is poor because of the large amount of Al (aluminum) and the small amount of P (phosphorus) as a network component.

[0010] Therefore, the object of the present invention is to provide optical glass, optical element blanks, glass materials for pressing, and optical elements that have anomalous partial dispersion and stability upon reheating. For this purpose, an exploration was conducted into glass capable of improving stability upon reheating while maintaining anomalous partial dispersion, resulting in the present invention.

[0011] Problem Solving Methods

[0012] The main points of this invention are as follows.

[0013] (1) An optical glass, wherein...

[0014] The molar ratio of F to Al [F / Al] is 2.50–15.0.

[0015] The molar ratio of Ba to P [Ba / P] is 0.100–1.20.

[0016] The molar ratio of P to Al [P / Al] is 0.200–2.00.

[0017] The molar ratio of O to P [O / P] is 3.05 to 4.20.

[0018] (2) The optical glass according to (1), wherein,

[0019] The total content of Li, Na and K [Li+Na+K] is 0.00 to 10.0 mol%.

[0020] (3) The optical glass according to (1) or (2), wherein,

[0021] The molar ratio of F to Al [F / Al] is 2.70–4.60.

[0022] The molar ratio of Ba to P [Ba / P] is 0.100–1.10.

[0023] The molar ratio of P to Al [P / Al] is 1.50–2.00.

[0024] The molar ratio of O to P [O / P] is 3.55 to 4.00.

[0025] (4) The optical glass according to (1) or (2), wherein,

[0026] The molar ratio of F to Al [F / Al] is 2.50–4.60.

[0027] The molar ratio of Ba to P [Ba / P] is 0.250–1.20.

[0028] The molar ratio of P to Al [P / Al] is 1.50–2.00.

[0029] The molar ratio of O to P [O / P] is 3.55 to 3.80.

[0030] (5) The optical glass according to (1) or (2), wherein,

[0031] The molar ratio of F to Al [F / Al] is 4.60–15.0.

[0032] The molar ratio of Ba to P [Ba / P] is 0.100–1.20.

[0033] The molar ratio of P to Al [P / Al] is 0.200–0.900.

[0034] The molar ratio of O to P [O / P] is 3.60–4.20.

[0035] The molar ratio of F content to the total content of O, F, and Cl [F / (O+F+Cl)] is 0.010–0.790.

[0036] The molar ratio of the total content of Sr and Ba to the total content of Mg, Ca, Sr, Ba and Zn [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] is 0.00 to 0.67.

[0037] (6) The optical glass according to (1), wherein,

[0038] The molar ratio of F to Al [F / Al] is 4.60–15.0.

[0039] The molar ratio of Ba to P [Ba / P] is 0.100–1.20.

[0040] The molar ratio of P to Al [P / Al] is 0.200–0.900.

[0041] The molar ratio of O to P [O / P] is 3.60–4.20.

[0042] The molar ratio of F content to the total content of O, F and Cl [F / (O+F+Cl)] is 0.010 to 0.790, and the total content of Li, Na and K [Li+Na+K] is 0.00 to 5.00 mol%.

[0043] (7) The optical glass according to (1) or (2), wherein,

[0044] The molar ratio of F to Al [F / Al] is 4.60–15.0.

[0045] The molar ratio of Ba to P [Ba / P] is 0.400–0.820.

[0046] The molar ratio of P to Al [P / Al] is 0.20–1.25.

[0047] The molar ratio of O to P [O / P] is 3.05–3.49.

[0048] The molar ratio of F content to the total content of O, F, and Cl [F / (O+F+Cl)] is 0.010–0.790.

[0049] The molar ratio of the total content of Sr and Ba to the total content of Mg, Ca, Sr, Ba and Zn [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] is 0.00 to 0.67.

[0050] (8) The optical glass according to (1), wherein,

[0051] The molar ratio of F to Al [F / Al] is 4.60–15.0.

[0052] The molar ratio of Ba to P [Ba / P] is 0.400–0.820.

[0053] The molar ratio of P to Al [P / Al] is 0.20–1.25.

[0054] The molar ratio of O to P [O / P] is 3.05–3.49.

[0055] The molar ratio of F content to the total content of O, F and Cl [F / (O+F+Cl)] is 0.010 to 0.790, and the total content of Li, Na and K [Li+Na+K] is 0.00 to 6.40 mol%.

[0056] (9) An optical glass, wherein...

[0057] The contents of F, Al, Ba, P and O, expressed as mass percent, are set as C(F), C(Al), C(Ba), C(P) and C(O), respectively.

[0058] Let the atomic weights of F, Al, Ba, P, and O be M(F), M(Al), M(Ba), M(P), and M(O), respectively.

[0059] And set it as:

[0060] A1={C(F) / M(F)} / {C(Al) / M(Al)}

[0061] B1={C(Ba) / M(Ba)} / {C(P) / M(P)}

[0062] C1={C(P) / M(P)} / {C(Al) / M(Al)}

[0063] When D1 = {C(O) / M(O)} / {C(P) / M(P)},

[0064] A1 ranges from 2.50 to 15.0.

[0065] B1 ranges from 0.100 to 1.20.

[0066] C1 ranges from 0.200 to 2.00.

[0067] D1 ranges from 3.05 to 4.20.

[0068] (10) An optical element blank made of any one of the optical glass described in (1) to (9) above.

[0069] (11) A glass material for pressing and molding, which is made of any one of the optical glass described in (1) to (9) above.

[0070] (12) An optical element made of any one of the optical glass described in (1) to (9) above.

[0071] The effects of the invention

[0072] According to the present invention, optical glass, optical element blanks, glass materials for pressing and molding, and optical elements with anomalous partial dispersion and stability upon reheating can be provided. Attached Figure Description

[0073] Figure 1 This is a reference graph used to calculate the rise temperature Tx of the exothermic peak during crystallization and the glass transition temperature Tg. Detailed Implementation

[0074] The embodiments of the present invention will be described below. It should be noted that the content of the glass components can be quantified using known methods, such as inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). Elements that are anionic components, such as O, F, and Cl, can be identified and quantified using known analytical methods, such as ion chromatography and non-dispersive infrared absorption spectrometry (ND-IR).

[0075] 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, as in reheat pressing.

[0076] Unless otherwise specified, the refractive index in this specification refers to the refractive index nd under helium d rays (wavelength 587.56 nm).

[0077] The Abbe number νd is used as a value to represent properties related to dispersion, and is expressed by the following mathematical formula. Where nF is the refractive index of blue hydrogen under F-rays (wavelength 486.13 nm) and nC is the refractive index of red hydrogen under C-rays (656.27 nm).

[0078] νd=(nd-1) / (nF-nC)

[0079] In this invention, the glass composition of the optical glass is expressed in mole % and mass % (%). Mole % refers to the molar percentage when the total content of all elements contained in the glass is set to 100%. Furthermore, molar ratio refers to the ratio calculated based on the content of elements expressed in mole % (%). Mass % refers to the mass percentage when the total content of all elements contained in the glass is set to 100%. In this specification and this invention, a content of 0% for a constituent element means that the constituent element is substantially absent, but its presence at an unavoidable impurity level is permissible.

[0080] Hereinafter, embodiments of the optical glass of the present invention will be described. It should be noted that the first embodiment (first-1 embodiment and 1-2 embodiment), the second embodiment (second-1 embodiment and 2-2 embodiment), and the third embodiment (third-1 embodiment and 3-2 embodiment) described below are preferred embodiments of this invention.

[0081] This implementation method

[0082] In this embodiment, specifically by controlling the ratio of Al content to F content, an optical glass capable of improving stability during reheating while ensuring anomalous partial dispersion is achieved. The optical glass of this embodiment is described below.

[0083] In the optical glass of this embodiment,

[0084] The molar ratio of F to Al [F / Al] is 2.50–15.0.

[0085] The molar ratio of Ba to P [Ba / P] is 0.100–1.20.

[0086] The molar ratio of P to Al [P / Al] is 0.200–2.00.

[0087] The molar ratio of O to P [O / P] is 3.05 to 4.20.

[0088] Furthermore, in the optical glass of this embodiment,

[0089] The contents of F, Al, Ba, P and O, expressed as mass percent, are set as C(F), C(Al), C(Ba), C(P) and C(O), respectively.

[0090] Let the atomic weights of F, Al, Ba, P, and O be M(F), M(Al), M(Ba), M(P), and M(O), respectively.

[0091] And set it as:

[0092] A1={C(F) / M(F)} / {C(Al) / M(Al)}

[0093] B1={C(Ba) / M(Ba)} / {C(P) / M(P)}

[0094] C1={C(P) / M(P)} / {C(Al) / M(Al)}

[0095] When D1 = {C(O) / M(O)} / {C(P) / M(P)},

[0096] A1 ranges from 2.50 to 15.0.

[0097] B1 ranges from 0.100 to 1.20.

[0098] C1 ranges from 0.200 to 2.00.

[0099] D1 ranges from 3.05 to 4.20.

[0100] In this invention, the atomic weights of each element are referenced to those described in Table 2 of Reference 1 (Pure Appl. Chem., Vol. 75, No. 8, pp. 1107-1122, 2003). Furthermore, A1, B1, C1, and D1 are values ​​representing the molar ratios [F / Al], [Ba / P], [P / Al], and [O / P] using their content and atomic weight as expressed in mass percent, respectively.

[0101] In this invention, the molar ratio [O / P] is the ratio of the content of O to the content of P expressed in mole percent, but it can also be calculated as described below.

[0102] Methods for calculating the O / P ratio

[0103] The optical glass of the present invention is an insulator that does not absorb at least in the visible to near-infrared region, and its formal valence can be considered essentially 0 (electrically neutral). Therefore, for the optical glass of the present invention, the mass percentages of m elements α1, α2…αm that can be cations and n elements β1, β2…βn that can be anions are set as C(α1), C(α2),…C(αm), and C(β1), C(β2),…C(βn).

[0104] 1) Let the atomic weights of the elements α1, α2…αm that can be cations and the elements β1, β2…βn that can be anions be M(α1), M(α2),…M(αm), and M(β1), M(β2),…M(βn), respectively.

[0105] 2) When the valences of cations α1, α2…αm and anions β1, β2…βn are set as V(α1), V(α2),…V(αm) and V(β1), V(β2),…V(βn), respectively,

[0106] It can be considered to have the following relationship:

[0107] Σ(i=1~m){[C(αi) / M(αi)]×V(αi)}=-Σ(j=1~n){[C(βj / M(βj)]×V(βj)}.

[0108] This relationship can also be used to calculate the content of O element based on the content (mass%) of elements other than O. This is effective, for example, when it is difficult to determine the content of O, or when the determination results of O content are highly biased.

[0109] The following are specific examples to illustrate this.

[0110] Calculation Example

[0111] As shown in Table I below, for glasses formed from elements F, Al, Ba, P and O, the contents of each element other than O, expressed as mass percentages, are quantified as 27.035 wt%, 7.384 wt%, 52.614 wt%, and 5.086 wt%, respectively.

[0112] [Table I]

[0113] Table I

[0114]

[0115] Regarding F, Al, Ba, P, and O,

[0116] 1) Set the formal valences of F, Al, Ba, P, and O to V(F) = -1, V(Al) = +3, V(Ba) = +2, V(P) = +5, and V(O) = -2, respectively.

[0117] 2) When the atomic weights of F, Al, Ba, P and O are set as M(F) = 18.9984, M(Al) = 26.9815, M(Ba) = 137.3277, M(P) = 30.9738 and M(O) = 15.9994 respectively, the following equation (1) holds.

[0118] {[C(P) / M(P)]×V(P)+[C(Al) / M(Al)]×V(Al)+[C(Ba) / M(Ba)]×V(Ba)}={[C(O) / M(O)]×V(O)+[C(F) / M(F)]×V(F)}…Equation (1)

[0119] The following can be calculated using the above formula (1):

[0120] C(O) / M(O)={7.384 / 26.9815×3+52.614 / 137.3277×2+5.086 / 30.9738×5+27.035 / 18.9984×(-1)} / 2=0.4926….

[0121] Dividing C(O) / M(O) by C(P) / M(P) = 5.086 / 30.9738 = 0.1642…, we can then calculate:

[0122] D1={C(O) / M(O)} / {C(P) / M(P)}=3.00….

[0123] D1 is the value of the molar ratio [O / P] expressed in terms of content and atomic weight as a percentage of mass.

[0124] Furthermore, C(O) = {C(O) / M(O)} × M(O), therefore we can also calculate:

[0125] C(O) = 0.4926… × 15.9994 = 7.881… (mass%).

[0126] At this time, depending on the method for determining the content of glass components, there may be, for example, a small amount of undetermined elements, or due to measurement deviations, the total mass percentage of O content may not exactly reach 100%. However, if almost all elements other than O are quantified in mole percent, the above method can be used to calculate parameters such as D1 even without the determination results of O content.

[0127] For example, when converting elements to mole percent, the allowable deviation in the total amount can sometimes reach 100 ± 5%, but is preferably around 100 ± 3%, more preferably in the order of 100% ± 2%, 100% ± 1%, 100% ± 0.5%, 100% ± 0.3%, and 100% ± 0.1%. It is also possible to omit the determination of unavoidable impurities.

[0128] The optical glass of this embodiment will now be described in detail.

[0129] In the optical glass of this embodiment, the molar ratio of F content to Al content [F / Al] is 2.50 to 15.0. The lower limit of the molar ratio [F / Al] is preferably 2.60, and more preferably in the order of 2.70, 2.75, 2.80, 2.90, 3.00, 3.50, 4.00, 4.25, 4.50, and 4.60. Furthermore, the upper limit of the molar ratio [F / Al] is preferably 7.50, and more preferably in the order of 7.00, 6.75, 6.50, 6.25, and 6.00. By setting the molar ratio [F / Al] within the above range, optical glass with anomalous partial dispersion and stability upon reheating can be obtained. If the molar ratio [F / Al] is too small, there is a risk of reduced stability upon reheating. If the molar ratio [F / Al] is too large, there is a risk of ripples arising due to changes in the glass composition caused by the volatilization of F. In addition, especially from the viewpoint of increasing the refractive index nd of the glass and suppressing the ripples caused by the volatilization of the glass components while improving the stability during reheating, the upper limit of the molar ratio [F / Al] can also be set to 4.50, 4.25, 4.00, 3.75, or 3.50.

[0130] Furthermore, in the optical glass of this embodiment, when the contents of F and Al expressed as mass percent are set as C(F) and C(Al), respectively, and the atomic weights of F and Al are set as M(F) and M(Al), respectively, and A1 is set as A1 = {C(F) / M(F)} / {C(Al) / M(Al)}, A1 is 2.50 to 15.0. The lower limit of A1 is preferably 2.60, and more preferably in the order of 2.70, 2.75, 2.80, 2.90, 3.00, 3.50, 4.00, 4.25, 4.50, and 4.60. The upper limit of A1 is preferably 7.50, and more preferably in the order of 7.00, 6.75, 6.50, 6.25, and 6.00. By setting A1 within the above range, an optical glass with abnormal partial dispersion and stability upon reheating can be obtained. If A1 is too small, there is a risk of reduced stability upon reheating. When A1 is too high, there is a risk of glass ripples due to changes in the glass composition caused by the volatilization of fluorine (F). In addition, especially from the viewpoint of increasing the refractive index of the glass and suppressing ripples caused by the volatilization of glass components while improving stability during reheating, the upper limit of A1 can be set to 4.50, 4.25, 4.00, 3.75, or 3.50.

[0131] In the optical glass of this embodiment, the molar ratio of Ba content to P content [Ba / P] is 0.100 to 1.20. The lower limit of the molar ratio [Ba / P] is preferably 0.200, and more preferably in the order of 0.300, 0.350, 0.375, 0.400, 0.425, 0.450, 0.460, 0.480, and 0.500. Furthermore, the upper limit of the molar ratio [Ba / P] is preferably 1.15, and more preferably in the order of 1.30, 1.20, 1.10, 1.05, 1.00, 0.900, 0.800, 0.700, 0.650, and 0.600. By setting the molar ratio [Ba / P] within the above range, an optical glass with anomalous partial dispersion can be obtained. If the molar ratio [Ba / P] is too small, there is a risk of a decrease in refractive index; furthermore, when manufacturing a lens, there is a risk of affecting image formation. When the molar ratio [Ba / P] is too high, there is a risk that a network structure cannot be formed, thus preventing glass transition. Additionally, there is a risk of Ba precipitation. Furthermore, there is a risk of reduced stability upon reheating.

[0132] Furthermore, in the optical glass of this embodiment, when the contents of Ba and P, expressed as mass percent, are set as C(Ba) and C(P), respectively, and the atomic weights of Ba and P are set as M(Ba) and M(P), respectively, and B1 is set as B1 = {C(Ba) / M(Ba)} / {C(P) / M(P)}, B1 is 0.100 to 1.50. The lower limit of B1 is preferably 0.200, and more preferably in the order of 0.300, 0.350, 0.375, 0.400, 0.425, 0.450, 0.460, 0.480, and 0.500. The upper limit of B1 is preferably 1.40, and more preferably in the order of 1.30, 1.20, 1.10, 1.05, 1.00, 0.900, 0.800, 0.700, 0.650, and 0.600. By setting B1 within the aforementioned range, optical glass with anomalous partial dispersion can be obtained. If B1 is too small, there is a risk of reduced refractive index, and in the case of lens fabrication, there is a risk of affecting image formation. If B1 is too large, there is a risk that a network structure cannot be formed, thus preventing vitrification, and there is also a risk of Ba precipitation.

[0133] In the optical glass of this embodiment, the molar ratio of P to Al [P / Al] is 0.200 to 2.00. The lower limit of the molar ratio [P / Al] is preferably 0.250, and more preferably in the order of 0.300, 0.350, 0.400, 0.450, 0.475, 1.00, 1.20, 1.30, 1.40, and 1.45. Furthermore, the upper limit of the molar ratio [P / Al] is preferably 1.95, and more preferably in the order of 1.90, 1.85, 1.80, and 1.75. By setting the molar ratio [P / Al] within the above range, optical glass exhibiting anomalous partial dispersion and stability upon reheating can be obtained. The preferred range of the molar ratio [P / Al] varies in relation to the F content. When the F content is high, the Al content must be increased to suppress the generation of frenulum, resulting in a lower molar ratio [P / Al]. Furthermore, when the F content is low, in order to suppress the decrease in stability during reheating, the P content must be increased and the Al content decreased, resulting in a larger molar ratio [P / Al]. Additionally, particularly from the viewpoint of increasing the glass's refractive index and suppressing ripples caused by the volatilization of glass components while improving stability during reheating, the upper limit of the molar ratio [P / Al] can be set to 1.20, 1.00, 0.900, 0.800, 0.700, or 0.600.

[0134] Furthermore, in the optical glass of this embodiment, when the contents of Al and P, expressed as mass percent, are set as C(Al) and C(P), respectively, and the atomic weights of Al and P are set as M(Al) and M(P), respectively, and C1 is set as C1 = {C(P) / M(P)} / {C(Al) / M(Al)}, C1 is 0.200 to 2.00. The lower limit of C1 is preferably 0.250, and more preferably in the order of 0.300, 0.350, 0.400, 0.450, 0.475, 1.00, 1.20, 1.30, 1.40, and 1.45. The upper limit of C1 is preferably 1.95, and more preferably in the order of 1.90, 1.85, 1.80, and 1.75. By setting C1 within the above range, an optical glass with anomalous partial dispersion and stability upon reheating can be obtained. The contents of C1 and F change in tandem. When the fluorine (F) content is high, the al (Al) content must be increased to suppress the formation of glass ripples, resulting in a decrease in chromatic precipitate (C1). Conversely, when the fluorine (F) content is low, the phosphorus (P) content must be increased and the al (Al) content decreased to suppress the decrease in stability during reheating, resulting in a higher C1. Furthermore, specifically from the viewpoint of increasing the refractive index of the glass and suppressing glass ripples caused by the volatilization of glass components while improving stability during reheating, the upper limit of C1 can be set at 1.20, 1.00, 0.900, 0.800, 0.700, or 0.600.

[0135] In the optical glass of this embodiment, the molar ratio of O to P [O / P] is 3.05 to 4.20. The lower limit of the molar ratio [O / P] is preferably 3.10, and more preferably in the order of 3.15, 3.20, 3.25, 3.30, 3.35, 3.40, 3.45, 3.50, 3.55, and 3.575. Furthermore, the upper limit of the molar ratio [O / P] is preferably 4.10, and more preferably in the order of 4.00, 3.95, 3.90, 3.85, 3.80, and 3.78. By setting the molar ratio [O / P] within the above range, an optical glass with abnormal partial dispersion and stability upon reheating can be obtained. In the optical glass of this embodiment, due to the volatilization of F, P also becomes more volatile. Therefore, if the molar ratio [O / P] is too small, there is a risk that the volatilization of F will increase, leading to changes in the glass composition and the formation of ripples. When the atomic ratio is too high, there is a risk of impaired dispersion in anomalous areas. Additionally, there is a risk of reduced thermal stability and stability upon reheating of the glass. Furthermore, particularly from the viewpoint of increasing the refractive index of the glass and suppressing ripples caused by the volatilization of glass components while improving stability upon reheating, the upper limit of the molar ratio [O / P] can be set to 3.49, 3.48, 3.44, or 3.40.

[0136] Furthermore, in the optical glass of this embodiment, when the contents of P and O, expressed as mass percent, are set as C(P) and C(O), respectively, and the atomic weights of P and O are set as M(P) and M(O), respectively, and D1 is set as {C(O) / M(O)} / {C(P) / M(P)}, D1 is 3.05 to 4.20. The lower limit of D1 is preferably 3.10, and more preferably in the order of 3.15, 3.20, 3.25, 3.30, 3.35, 3.40, 3.45, 3.50, 3.55, and 3.575. The upper limit of D1 is preferably 4.10, and more preferably in the order of 4.00, 3.95, 3.90, 3.85, 3.80, and 3.78. By setting D1 within the above range, an optical glass with anomalous partial dispersion and stability upon reheating can be obtained. In the optical glass of this embodiment, the volatilization of phosphorus (F) causes phosphorus (P) to become more volatile. Therefore, if D1 is too small, there is a risk that the volatilization of F will have a greater impact, leading to changes in the glass composition and the formation of ripples. If the atomic ratio is too large, there is a risk of impaired dispersion in anomalous regions, and also a risk of reduced thermal stability and stability upon reheating. Furthermore, from the viewpoint of increasing the refractive index of the glass and suppressing ripples caused by the volatilization of glass components while improving stability upon reheating, the upper limit of D1 can be set to 3.49, 3.48, 3.44, or 3.40.

[0137] Regarding the content and ratio of glass components other than those described above in the optical glass of this embodiment, non-limiting examples are shown below.

[0138] In the optical glass of this embodiment, from the viewpoint of improving the meltability of the glass raw materials, the lower limit of the total content of Li and Na [Li+Na] is preferably 0.00 mol%, and more preferably in the order of 0.03 mol%, 0.07 mol%, and 0.10 mol%. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the total content [Li+Na] is preferably 10.0 mol%, and more preferably in the order of 7.0 mol%, 5.0 mol%, and 3.0 mol%.

[0139] Furthermore, in the optical glass of this embodiment, when the contents of Li and Na expressed as mass percent are set as C(Li) and C(Na), respectively, and the atomic weights of Li and Na are set as M(Li) and M(Na), respectively, and E1 is set as E1 = [{C(Li) / M(Li)} + {C(Na) / M(Na)}] × 100, from the viewpoint of improving the meltability of the glass raw material, the lower limit of E1 is preferably 0, and more preferably in the order of 0.09, 0.21, and 0.30. From the viewpoint of suppressing the volatilization of glass components, the upper limit of E1 is preferably 30, and more preferably in the order of 21, 15, and 9.

[0140] In the optical glass of this embodiment, from the viewpoint of improving the meltability of the glass raw materials, the lower limit of the total content of Li, Na, and K [Li+Na+K] is preferably 0.00 mol%, and more preferably in the order of 0.04 mol%, 0.08 mol%, 0.12 mol%, 0.16 mol%, and 0.18 mol%. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the total content [Li+Na+K] is preferably 7.6 mol%, and more preferably in the order of 7.20 mol%, 6.40 mol%, 6.20 mol%, 6.00 mol%, 5.80 mol%, 5.60 mol%, 5.40 mol%, 5.20 mol%, 4.80 mol%, and 4.40 mol%.

[0141] Furthermore, in the optical glass of this embodiment, the contents of Li, Na, and K, expressed as mass percent, are set as C(Li), C(Na), and C(K), respectively, and the atomic weights of Li, Na, and K are set as M(Li), M(Na), and M(K), respectively. When F1 is set as F1 = [{C(Li) / M(Li)} + {C(Na) / M(Na)} + {C(K) / M(K)}] × 100, from the viewpoint of improving the meltability of the glass raw material, the lower limit of F1 is preferably 0, and more preferably in the order of 0.12, 0.24, 0.36, 0.48, and 0.54. From the viewpoint of suppressing the volatilization of glass components, the upper limit of F1 is preferably 24.0, and more preferably in the order of 22.8, 21.6, 19.2, 18.6, 18.0, 17.4, 16.8, 16.2, 15.6, 14.4, and 13.2.

[0142] In the optical glass of this embodiment, from the viewpoint of imparting anomalous partial dispersion and improving thermal stability, the lower limit of the molar ratio of F content to the total content of O, F, and Cl [F / (O+F+Cl)] is preferably 0.010, and more preferably in the order of 0.110, 0.160, 0.220, 0.250, 0.280, 0.300, 0.320, 0.420, 0.450, 0.500, and 0.550. From the viewpoint of stabilizing the glass and suppressing volatilization, the upper limit of the molar ratio [F / (O+F+Cl)] is preferably 0.890, and more preferably in the order of 0.850, 0.820, 0.810, 0.800, 0.790, and 0.600. In particular, from the viewpoint of increasing the refractive index of the glass and suppressing the ripples caused by the volatilization of glass components while improving stability during reheating, the upper limit of the molar ratio [F / (O+F+Cl)] can also be set to 0.500, 0.460, 0.420, or 0.400.

[0143] Furthermore, in the optical glass of this embodiment, the contents of F, O, and Cl expressed as mass% are set as C(F), C(O), and C(Cl), respectively, and the atomic weights of F, O, and Cl are set as M(F), M(O), and M(Cl), respectively. When G1 is set as G1 = [{C(F) / M(F)} / [{C(O) / M(O)}+{C(F) / M(F)}+{C(Cl) / M(Cl)}]], from the viewpoint of imparting anomalous dispersion and improving thermal stability, the lower limit of G1 is preferably 0.010, and more preferably in the order of 0.110, 0.160, 0.220, 0.250, 0.280, 0.300, 0.320, 0.420, 0.450, 0.500, 0.550, 0.600, 0.625, and 0.650. From the viewpoint of stabilizing the glass and suppressing volatilization, the upper limit of G1 is preferably 0.940, and more preferably in the order of 0.890, 0.850, 0.820, 0.810, 0.800, 0.790, and 0.600. In particular, from the viewpoint of increasing the refractive index of the glass and suppressing ripples caused by volatilization of glass components while improving stability during reheating, the upper limit of G1 can also be set to 0.550, 0.500, 0.460, 0.420, or 0.400.

[0144] In the optical glass of this embodiment, from the viewpoint of improving the refractive index nd, the lower limit of the molar ratio of the total content of Sr and Ba to the total content of Mg, Ca, Sr, Ba and Zn [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] is preferably 0.100, and more preferably in the order of 0.200, 0.300, 0.340, 0.380, 0.420, and 0.460. From the viewpoint of improving stability during reheating, the upper limit of the molar ratio [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] is preferably 1.00, and more preferably in the order of 0.990, 0.980, 0.970, 0.850, 0.800, 0.750, 0.700, 0.650, and 0.600. Especially in glasses with low fluorine content, from the viewpoint of increasing the refractive index nd of the glass, the lower limit of the molar ratio [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] can also be set to 0.500, 0.600, 0.700, or 0.750.

[0145] Furthermore, in the optical glass of this embodiment, the contents of Mg, Ca, Sr, Ba, and Zn, expressed as mass percent, are set as C(Mg), C(Ca), C(Sr), C(Ba), and C(Zn), respectively; the atomic weights of Mg, Ca, Sr, Ba, and Zn are set as M(Mg), M(Ca), M(Sr), M(Ba), and M(Zn), respectively; and H1 is set as H1 = [{C(Sr) / M(Sr)} + ​​{C(Ba)}. When H1 is defined as [{C(Mg) / M(Mg)}+{C(Ca) / M(Ca)}+{C(Sr) / M(Sr)}+{C(Ba) / M(Ba)}+{C(Zn) / M(Zn)}], from the viewpoint of increasing the refractive index nd, the lower limit of H1 is preferably 0.100, and more preferably in the order of 0.200, 0.300, 0.340, 0.380, 0.420, and 0.460. From the viewpoint of improving stability during reheating, the upper limit of H1 is preferably 1.00, and more preferably in the order of 0.990, 0.980, 0.970, 0.850, 0.800, 0.750, 0.700, 0.650, and 0.600. Especially in glasses with low fluorine content, from the perspective of increasing the refractive index nd of the glass, the lower limit of H1 can also be set to 0.500, 0.600, 0.700, 0.750, 0.800, 0.850, or 0.900.

[0146] In the optical glass of this embodiment, from the viewpoint of improving the refractive index, the lower limit of the molar ratio of the total content of Ba, Sr, and Zn to the content of P [(Ba+Sr+Zn) / P] is preferably 0.100, and more preferably in the order of 0.200, 0.300, 0.400, 0.500, 0.550, 0.600, 0.650, 0.700, 0.750, and 0.800. From the viewpoint of improving stability during reheating, the upper limit of the molar ratio [(Ba+Sr+Zn) / P] is preferably 2.10, and more preferably in the order of 1.90, 1.80, 1.70, 1.60, 1.50, 1.40, 1.30, 1.20, 1.15, 1.12, and 1.10.

[0147] Furthermore, in the optical glass of this embodiment, the contents of P, Sr, Ba, and Zn expressed in mass percent are set as C(P), C(Sr), C(Ba), and C(Zn), respectively, and the atomic weights of P, Sr, Ba, and Zn are set as M(P), M(Sr), M(Ba), and M(Zn), respectively. When I1 is set as I1 = [{C(Ba) / M(Ba)} + {C(Sr) / M(Sr)} + ​​{C(Zn) / M(Zn)}] / {C(P) / M(P)}, from the viewpoint of increasing the refractive index, the lower limit of I1 is preferably 0.100, and more preferably in the order of 0.200, 0.300, 0.400, 0.500, 0.550, 0.600, 0.650, 0.700, 0.750, 0.800, 0.850, 0.900, and 0.950. From the viewpoint of improving stability during reheating, the upper limit of I1 is preferably 3.00, and even more preferably in the order of 2.50, 2.20, 2.10, 2.00, 1.90, 1.80, 1.70, 1.60, 1.50, 1.40, 1.30, 1.20, 1.15, 1.12, and 1.10.

[0148] In the optical glass of this embodiment, from the viewpoint of improving the meltability of the glass raw materials, the lower limit of the total content of Sr and Li [Sr+Li] is preferably 0.0 mol%, and more preferably in the order of 0.2 mol%, 0.4 mol%, 0.6 mol%, 0.8 mol%, 1.0 mol%, and 1.2 mol%. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the total content [Sr+Li] is preferably 11.4 mol%, and more preferably in the order of 10.6 mol%, 9.8 mol%, 9.0 mol%, 4.0 mol%, 3.6 mol%, 3.2 mol%, 2.8 mol%, 2.4 mol%, 2.0 mol%, and 1.8 mol%.

[0149] Furthermore, in the optical glass of this embodiment, the contents of Li and Sr, expressed as mass percent, are set as C(Li) and C(Sr), respectively, and the atomic weights of Li and Sr are set as M(Li) and M(Sr), respectively. When J1 is set as J1 = [{C(Li) / M(Li)} + {C(Sr) / M(Sr)}] × 100, from the viewpoint of improving the meltability of the glass raw material, the lower limit of J1 is preferably 0, and more preferably in the order of 0.6, 1.2, 1.8, 2.4, 3.0, and 3.6. From the viewpoint of suppressing the volatilization of glass components, the upper limit of J1 is preferably 42.0, and more preferably in the order of 39.0, 36.6, 34.2, 31.8, 29.4, 27.0, 12.0, 10.8, 9.6, 8.4, 7.2, 6.0, and 5.4.

[0150] In the optical glass of this embodiment, from the viewpoint of improving the refractive index (nd) and chemical durability, the lower limit of the total content of Y, La, Gd, Yb, and Lu [Y+La+Gd+Yb+Lu] is preferably 0.0 mol%, and more preferably in the order of 0.04 mol%, 0.08 mol%, 0.12 mol%, 0.16 mol%, 0.20 mol%, 0.24 mol%, 0.28 mol%, 0.32 mol%, 0.36 mol%, and 0.40 mol%. From the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the upper limit of the total content [Y+La+Gd+Yb+Lu] is preferably 2.0 mol%, and more preferably in the order of 1.6 mol%, 1.4 mol%, 1.2 mol%, 1.0 mol%, 0.90 mol%, and 0.80 mol%. From the viewpoint of improving stability during reheating and reducing glass brittleness, the upper limit of the total content [Y+La+Gd+Yb+Lu] can also be set at 0.52 mol%, 0.48 mol%, 0.44 mol%, or 0.40 mol%.

[0151] Furthermore, in the optical glass of this embodiment, the contents of Y, La, Gd, Yb, and Lu, expressed as mass percent, are set as C(Y), C(La), C(Gd), C(Yb), and C(Lu), respectively; the atomic weights of Y, La, Gd, Yb, and Lu are set as M(Y), M(La), M(Gd), M(Yb), and M(Lu), respectively; and K1 is set as K1 = [{C(Y) / M(Y)} + {C(La) / M(La)}. When K1 is calculated as [{C(Gd) / M(Gd)}+{C(Yb) / M(Yb)}+{C(Lu) / M(Lu)}]×100, from the viewpoint of increasing the refractive index nd and improving chemical durability, the lower limit of K1 is preferably 0, and more preferably in the order of 0.12, 0.24, 0.36, 0.48, 0.60, 0.72, 0.84, 0.96, 1.08, 1.20, 1.32, and 1.44. From the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the upper limit of K1 is preferably 9.00, and more preferably in the order of 7.50, 6.00, 4.80, 4.20, 3.60, 3.00, 2.70, 2.40, and 1.56. From the perspective of improving stability during reheating and reducing the brittleness of the glass, the upper limit of K1 can also be set to 1.44, 1.32, or 1.20.

[0152] In the optical glass of this embodiment, from the viewpoint of suppressing the volatilization of glass components, the lower limit of the O content is preferably 5 mol%, and more preferably in the order of 8 mol%, 10 mol%, 12 mol%, 13 mol%, and 14 mol%. From the viewpoint of improving stability during reheating, the upper limit of the O content is preferably 47 mol%, and more preferably in the order of 46 mol%, 44 mol%, 42 mol%, 40 mol%, and 36 mol%. In addition, particularly from the viewpoint of improving the refractive index nd of the glass and suppressing ripples caused by the volatilization of glass components, the lower limit of the O content can also be set to 28 mol%, 32 mol%, 36 mol%, 38 mol%, or 39 mol%. From the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the upper limit of the O content can also be set to 32 mol%, 28 mol%, 26 mol%, 25 mol%, or 24 mol%.

[0153] Furthermore, in the optical glass of this embodiment, from the viewpoint of suppressing the volatilization of glass components, the lower limit of the O content is preferably 2.42% by mass, and more preferably in the order of 3.88% by mass, 4.85% by mass, 5.82% by mass, 6.30% by mass, and 6.79% by mass. From the viewpoint of improving stability during reheating, the upper limit of the O content is preferably 32.00% by mass, and more preferably in the order of 29.33% by mass, 27.73% by mass, 26.13% by mass, 25.07% by mass, 24.53% by mass, 23.47% by mass, 22.40% by mass, and 21.33% by mass. In addition, particularly from the viewpoint of improving the refractive index nd of the glass and suppressing ripples caused by the volatilization of glass components, the lower limit of the O content can also be set to 13.58% by mass, 15.51% by mass, 17.45% by mass, 18.42% by mass, 18.91% by mass, or 19.39% by mass. From the perspective of improving the meltability of glass raw materials and improving the resistance to devitrification during melting, the upper limit of O content can also be set at 19.20% by mass, 17.07% by mass, 14.93% by mass, 13.87% by mass, 13.33% by mass, or 12.80% by mass.

[0154] In the optical glass of this embodiment, from the viewpoint of improving stability during reheating, the lower limit of the F content is preferably 10 mol%, and more preferably in the order of 13 mol%, 16 mol%, 18 mol%, 19 mol%, and 20 mol%. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the F content is preferably 60 mol%, and more preferably in the order of 58 mol%, 57 mol%, 56 mol%, and 55 mol%. From the viewpoint of further improving low dispersion and anomalous partial dispersion, the lower limit of the F content can also be set to 36 mol%, 40 mol%, 42 mol%, 44 mol%, or 45 mol%. From the viewpoint of improving the refractive index nd, the upper limit of the F content can also be set to 38 mol%, 34 mol%, 30 mol%, 28 mol%, 27 mol%, or 26 mol%.

[0155] Furthermore, in the optical glass of this embodiment, from the viewpoint of improving stability during reheating, the lower limit of the F content is preferably 5.76% by mass, and more preferably in the order of 7.48% by mass, 9.21% by mass, 10.36% by mass, 10.94% by mass, and 11.51% by mass. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the F content is preferably 44.33% by mass, and more preferably in the order of 41.16% by mass, 39.26% by mass, 38.00% by mass, 36.73% by mass, 36.10% by mass, 35.46% by mass, and 34.83% by mass. From the viewpoint of further improving low dispersion and anomalous partial dispersion, the lower limit of the F content can also be set to 20.73% by mass, 23.03% by mass, 24.18% by mass, 25.33% by mass, 25.91% by mass, or 26.48% by mass. From the perspective of increasing the refractive index nd, the upper limit of the F content can also be set at 24.06 mass%, 21.53 mass%, 19.00 mass%, 17.73 mass%, 17.10 mass%, or 16.47 mass%.

[0156] In the optical glass of this embodiment, from the viewpoint of promoting clarification, the lower limit of the Cl content is preferably 0.00 mol%, and more preferably in the order of 0.01 mol%, 0.02 mol%, 0.03 mol%, 0.04 mol%, and 0.05 mol%. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the Cl content is preferably 2.40 mol%, and more preferably in the order of 1.60 mol%, 1.20 mol%, 0.80 mol%, 0.40 mol%, 0.32 mol%, 0.28 mol%, 0.24 mol%, 0.20 mol%, and 0.16 mol%.

[0157] Furthermore, in the optical glass of this embodiment, from the viewpoint of promoting clarification, the lower limit of the Cl content is preferably 0% by mass, and more preferably in the order of 0.01% by mass, 0.02% by mass, 0.03% by mass, 0.04% by mass, and 0.05% by mass. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the Cl content is preferably 2.84% by mass, and more preferably in the order of 1.89% by mass, 1.42% by mass, 0.95% by mass, 0.47% by mass, 0.38% by mass, 0.33% by mass, 0.28% by mass, 0.24% by mass, and 0.19% by mass.

[0158] In the optical glass of this embodiment, from the viewpoint of improving stability during reheating, the lower limit of the P content is preferably 0.8 mol%, and more preferably in the order of 1.6 mol%, 2.0 mol%, 2.4 mol%, 2.8 mol%, 3.2 mol%, 3.6 mol%, 3.8 mol%, 4.0 mol%, 4.2 mol%, and 4.4 mol%. Furthermore, from the viewpoint of improving the refractive index nd, the upper limit of the P content is preferably 16.0 mol%, and more preferably in the order of 15.0 mol%, 14.0 mol%, 13.6 mol%, 13.2 mol%, 12.8 mol%, 12.4 mol%, 12.0 mol%, 11.6 mol%, 11.4 mol%, and 11.2 mol%.

[0159] Furthermore, in the optical glass of this embodiment, from the viewpoint of improving stability during reheating, the lower limit of the P content is preferably 0.751% by mass, and more preferably in the order of 1.500% by mass, 1.880% by mass, 2.250% by mass, 2.630% by mass, 3.000% by mass, 3.380% by mass, 3.570% by mass, 3.750% by mass, 3.940% by mass, and 4.130% by mass. Furthermore, from the viewpoint of improving the refractive index nd, the upper limit of the P content is preferably 18.58% by mass, and more preferably in the order of 17.55% by mass, 16.52% by mass, 15.49% by mass, 14.45% by mass, 14.04% by mass, 13.63% by mass, 13.22% by mass, 12.80% by mass, 12.39% by mass, 11.98% by mass, 11.77% by mass, and 11.56% by mass.

[0160] In the optical glass of this embodiment, from the viewpoint of improving chemical durability, the lower limit of the Al content is preferably 2.00 mol%, and more preferably in the order of 2.60 mol%, 3.00 mol%, 3.40 mol%, 3.80 mol%, 4.20 mol%, 4.60 mol%, 5.00 mol%, 5.40 mol%, 5.80 mol%, and 6.20 mol%. Furthermore, from the viewpoint of improving stability upon reheating, the upper limit of the Al content is preferably 16.0 mol%, and more preferably in the order of 15.0 mol%, 14.0 mol%, 13.2 mol%, 12.6 mol%, 12.0 mol%, 11.6 mol%, 11.2 mol%, 10.8 mol%, and 10.4 mol%.

[0161] Furthermore, in the optical glass of this embodiment, from the viewpoint of improving chemical durability, the lower limit of the Al content is preferably 1.64% by mass, and more preferably in the order of 2.13% by mass, 2.45% by mass, 2.78% by mass, 3.11% by mass, 3.43% by mass, 3.76% by mass, 4.09% by mass, 4.42% by mass, 4.74% by mass, 5.07% by mass, 5.40% by mass, and 5.56% by mass. Furthermore, from the viewpoint of improving stability upon reheating, the upper limit of the Al content is preferably 14.39% by mass, and more preferably in the order of 13.49% by mass, 12.59% by mass, 11.87% by mass, 11.33% by mass, 10.79% by mass, 10.43% by mass, 10.07% by mass, 9.71% by mass, and 9.35% by mass.

[0162] In the optical glass of this embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the content of B is preferably 1.6 mol%, and more preferably in the order of 1.2 mol%, 0.8 mol%, 0.6 mol%, 0.5 mol%, 0.4 mol%, 0.3 mol%, 0.2 mol%, and 0.1 mol%. Furthermore, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the content of B is preferably 0 mol%. The content of B can be 0 mol%.

[0163] Furthermore, in the optical glass of this embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the B content is preferably 0.58% by mass, and more preferably in the order of 0.43% by mass, 0.29% by mass, 0.22% by mass, 0.18% by mass, 0.14% by mass, 0.11% by mass, 0.07% by mass, and 0.04% by mass. Additionally, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the B content is preferably 0% by mass. The B content can be 0% by mass.

[0164] In the optical glass of this embodiment, from the viewpoint of maintaining meltability and thermal stability and suppressing the volatilization of glass components, the upper limit of the Si content is preferably 1.60 mol%, and more preferably in the order of 1.20 mol%, 0.80 mol%, 0.40 mol%, and 0.20 mol%. Furthermore, the lower limit of the Si content is preferably 0 mol%. The Si content can be 0 mol%.

[0165] Furthermore, in the optical glass of this embodiment, from the viewpoint of maintaining meltability and thermal stability and suppressing the volatilization of glass components, the upper limit of the Si content is preferably 1.50% by mass, and more preferably in the order of 1.12% by mass, 0.75% by mass, 0.37% by mass, and 0.19% by mass. Additionally, the lower limit of the Si content is preferably 0% by mass. The Si content can be 0% by mass.

[0166] In the glass of this embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Li content is preferably 6.80 mol%, and more preferably in the order of 6.40 mol%, 6.00 mol%, 5.60 mol%, 5.20 mol%, 4.40 mol%, 4.00 mol%, 3.60 mol%, 3.20 mol%, 2.80 mol%, and 2.40 mol%. Furthermore, from the viewpoint of improving the meltability of the glass raw material, the lower limit of the Li content is preferably 0 mol%, and more preferably in the order of 0.08 mol%, 0.12 mol%, 0.14 mol%, 0.16 mol%, and 0.20 mol%.

[0167] Furthermore, in the glass of this embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Li content is preferably 1.85% by mass, and more preferably in the order of 1.67% by mass, 1.57% by mass, 1.48% by mass, 1.39% by mass, 1.30% by mass, 1.20% by mass, 1.02% by mass, 0.93% by mass, 0.83% by mass, 0.74% by mass, 0.65% by mass, and 0.56% by mass. Furthermore, from the viewpoint of improving the meltability of the glass raw material, the lower limit of the Li content is preferably 0% by mass, and more preferably in the order of 0.017% by mass, 0.025% by mass, 0.029% by mass, 0.034% by mass, and 0.042% by mass.

[0168] In the glass of this embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Na content is preferably 6.00 mol%, and more preferably in the order of 5.20 mol%, 4.40 mol%, 3.60 mol%, 2.80 mol%, 2.00 mol%, 1.60 mol%, 1.20 mol%, 0.80 mol%, and 0.40 mol%. Furthermore, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the Na content is preferably 0 mol%. The Na content can be 0 mol%.

[0169] Furthermore, in the glass of this embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Na content is preferably 4.60% by mass, and more preferably in the order of 3.98% by mass, 3.37% by mass, 2.76% by mass, 2.15% by mass, 1.53% by mass, 1.23% by mass, 0.92% by mass, 0.61% by mass, and 0.31% by mass. Additionally, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the Na content is preferably 0% by mass. The Na content can be 0% by mass.

[0170] In the optical glass of this embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the K content is preferably 5.20 mol%, and more preferably in the order of 4.40 mol%, 3.60 mol%, 2.80 mol%, 2.00 mol%, 1.60 mol%, 1.20 mol%, 0.80 mol%, and 0.40 mol%. From the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the K content is preferably 0 mol%. The K content can be 0 mol%.

[0171] Furthermore, in the optical glass of this embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the K content is preferably 6.78% by mass, and more preferably in the order of 5.73% by mass, 4.69% by mass, 3.65% by mass, 2.61% by mass, 2.09% by mass, 1.56% by mass, 1.04% by mass, and 0.52% by mass. From the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the K content is preferably 0% by mass. The K content can be 0% by mass.

[0172] In the optical glass of this embodiment, the upper limit of the Cs content is preferably 1.60 mol%, and more preferably in the order of 1.20 mol%, 0.80 mol%, 0.40 mol%, and 0.20 mol%. The lower limit of the Cs content is preferably 0 mol%. The Cs content can be 0 mol%. Cs has the effect of improving the thermal stability of glass, but if the content increases, there is a risk of reduced chemical durability and weather resistance. Therefore, it is preferable to set the Cs content within the above range.

[0173] In the optical glass of this embodiment, the upper limit of the Cs content is preferably 7.09% by mass, and more preferably in the order of 5.32% by mass, 3.54% by mass, 1.77% by mass, and 0.89% by mass. The lower limit of the Cs content is preferably 0% by mass. The Cs content can be 0% by mass. Cs has the effect of improving the thermal stability of glass, but if the content increases, there is a risk of reduced chemical durability and weather resistance. Therefore, it is preferable to set the Cs content within the above range.

[0174] In the optical glass of this embodiment, from the viewpoint of improving stability during reheating, mechanical strength, and thermal shock resistance, the lower limit of the Mg content is preferably 0 mol%, and more preferably in the order of 0.08 mol%, 0.16 mol%, 0.24 mol%, 0.32 mol%, 0.36 mol%, and 0.40 mol%. Furthermore, from the viewpoint of improving resistance to devitrification during melting, the upper limit of the Mg content is preferably 9.2 mol%, and more preferably in the order of 8.4 mol%, 7.6 mol%, 6.8 mol%, 6.0 mol%, 5.2 mol%, 4.4 mol%, 3.6 mol%, and 2.8 mol%.

[0175] Furthermore, in the optical glass of this embodiment, from the viewpoint of improving stability during reheating, mechanical strength, and thermal shock resistance, the lower limit of the Mg content is preferably 0% by mass, and more preferably in the order of 0.06% by mass, 0.12% by mass, 0.18% by mass, 0.24% by mass, 0.27% by mass, and 0.29% by mass. Furthermore, from the viewpoint of improving resistance to devitrification during melting, the upper limit of the Mg content is preferably 7.45% by mass, and more preferably in the order of 6.81% by mass, 6.16% by mass, 5.51% by mass, 4.86% by mass, 4.21% by mass, 3.56% by mass, 2.92% by mass, and 2.27% by mass.

[0176] In the optical glass of this embodiment, from the viewpoint of improving stability during reheating, mechanical strength, and thermal shock resistance, the lower limit of the Ca content is preferably 0 mol%, and more preferably in the order of 0.04 mol%, 0.08 mol%, 0.12 mol%, 0.16 mol%, 0.18 mol%, and 0.20 mol%. Furthermore, from the viewpoint of improving resistance to devitrification during melting, the upper limit of the Ca content is preferably 13.8 mol%, and more preferably in the order of 13.0 mol%, 12.2 mol%, 11.4 mol%, 10.6 mol%, 9.8 mol%, 9.0 mol%, 8.2 mol%, and 7.4 mol%.

[0177] Furthermore, in the optical glass of this embodiment, from the viewpoint of improving stability during reheating, mechanical strength, and thermal shock resistance, the lower limit of the Ca content is preferably 0% by mass, and more preferably in the order of 0.05% by mass, 0.10% by mass, 0.15% by mass, 0.19% by mass, 0.22% by mass, and 0.24% by mass. Furthermore, from the viewpoint of improving resistance to devitrification during melting, the upper limit of the Ca content is preferably 18.44% by mass, and more preferably in the order of 17.37% by mass, 16.30% by mass, 15.23% by mass, 14.16% by mass, 13.09% by mass, 12.02% by mass, 10.95% by mass, and 9.89% by mass.

[0178] In the optical glass of this embodiment, from the viewpoint of increasing the refractive index nd, the lower limit of the Sr content is preferably 0 mol%, and more preferably in the order of 0.02 mol%, 0.04 mol%, 0.06 mol%, 0.08 mol%, and 0.10 mol%. Furthermore, from the viewpoint of improving stability upon reheating, the upper limit of the Sr content is preferably 12.2 mol%, and more preferably in the order of 11.4 mol%, 10.6 mol%, 9.8 mol%, 9.0 mol%, 8.2 mol%, 7.4 mol%, 6.6 mol%, and 5.8 mol%.

[0179] Furthermore, in the optical glass of this embodiment, from the viewpoint of increasing the refractive index nd, the lower limit of the Sr content is preferably 0% by mass, and more preferably in the order of 0.05% by mass, 0.11% by mass, 0.16% by mass, 0.21% by mass, and 0.27% by mass. Furthermore, from the viewpoint of improving stability during reheating, the upper limit of the Sr content is preferably 35.63% by mass, and more preferably in the order of 33.30% by mass, 30.96% by mass, 28.62% by mass, 26.29% by mass, 23.95% by mass, 21.61% by mass, 19.28% by mass, and 16.94% by mass.

[0180] In the optical glass of this embodiment, from the viewpoint of increasing the refractive index (nd), the lower limit of the Ba content is preferably 0.4 mol%, and more preferably in the order of 0.8 mol%, 1.2 mol%, 1.6 mol%, 2.0 mol%, 2.2 mol%, 2.4 mol%, 2.6 mol%, 2.8 mol%, 3.0 mol%, and 3.1 mol%. From the viewpoint of improving stability upon reheating, the upper limit of the Ba content is preferably 17.0 mol%, and more preferably in the order of 16.0 mol%, 15.0 mol%, 14.0 mol%, 13.2 mol%, 12.6 mol%, 11.8 mol%, 11.4 mol%, 11.0 mol%, 10.8 mol%, and 10.6 mol%.

[0181] Furthermore, in the optical glass of this embodiment, from the viewpoint of increasing the refractive index nd, the lower limit of the Ba content is preferably 1.66% by mass, and more preferably in the order of 3.33% by mass, 4.99% by mass, 6.66% by mass, 8.32% by mass, 9.16% by mass, 9.99% by mass, 10.82% by mass, 11.65% by mass, 12.48% by mass, and 12.90% by mass. From the viewpoint of improving stability during reheating, the upper limit of the Ba content is preferably 86.97% by mass, and more preferably in the order of 82.40% by mass, 77.82% by mass, 73.24% by mass, 68.66% by mass, 64.09% by mass, 60.42% by mass, 57.68% by mass, 54.02% by mass, 52.18% by mass, 50.35% by mass, 49.44% by mass, and 48.52% by mass.

[0182] In the optical glass of this embodiment, from the viewpoint of improving the meltability of the glass raw material, the upper limit of the Zn content is preferably 2.0 mol%, and more preferably in the order of 1.6 mol%, 1.2 mol%, 0.8 mol%, and 0.4 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd, the lower limit of the Zn content is preferably 0 mol%. The Zn content can be 0 mol%.

[0183] Furthermore, in the optical glass of this embodiment, from the viewpoint of improving the meltability of the glass raw material, the upper limit of the Zn content is preferably 4.36% by mass, and more preferably in the order of 3.49% by mass, 2.62% by mass, 1.74% by mass, and 0.87% by mass. Additionally, from the viewpoint of maintaining the refractive index nd, the lower limit of the Zn content is preferably 0% by mass. The Zn content can be 0% by mass.

[0184] In the optical glass of this embodiment, from the viewpoint of improving the refractive index nd, the lower limit of the total content of Mg, Ca, Sr, Ba and Zn [Mg+Ca+Sr+Ba+Zn] is preferably 8.0 mol%, and more preferably in the order of 10.0 mol%, 11.0 mol%, 11.0 mol%, and 12.0 mol%. From the viewpoint of improving stability upon reheating, the upper limit of this total content is preferably 25.0 mol%, and more preferably in the order of 23.0 mol%, 21.0 mol%, 19.0 mol%, 18.0 mol%, and 17.0 mol%.

[0185] Furthermore, in the optical glass of this embodiment, the contents of Mg, Ca, Sr, Ba, and Zn expressed in mass% are set as C(Mg), C(Ca), C(Sr), C(Ba), and C(Zn), respectively, and the atomic weights of Mg, Ca, Sr, Ba, and Zn are set as M(Mg), M(Ca), M(Sr), M(Ba), and M(Zn), respectively. When L1 is set as L1 = [{C(Mg) / M(Mg)} + {C(Ca) / M(Ca)} + {C(Sr) / M(Sr)} + ​​{C(Ba) / M(Ba)} + {C(Zn) / M(Zn)}] × 100, from the viewpoint of increasing the refractive index nd, the lower limit of L1 is preferably 24.0, and more preferably in the order of 30.0, 33.0, and 36.0. From the viewpoint of improving stability during reheating, the upper limit of L1 is preferably 75.0, and more preferably in the order of 69.0, 63.0, 60.0 and 58.0.

[0186] In the optical glass of this embodiment, from the viewpoint of increasing the refractive index nd, the lower limit of the total content of Sr, Ba, and Zn [Sr+Ba+Zn] is preferably 3.0 mol%, and more preferably in the order of 4.0 mol%, 5.0 mol%, 6.0 mol%, 7.0 mol%, and 8.0 mol%. From the viewpoint of improving stability during reheating, the upper limit of this total content is preferably 20.0 mol%, and more preferably in the order of 18.0 mol%, 16.0 mol%, 14.0 mol%, 13.0 mol%, and 12.0 mol%.

[0187] In the optical glass of this embodiment, the contents of Sr, Ba, and Zn, expressed as mass percent, are set as C(Sr), C(Ba), and C(Zn), respectively, and the atomic weights of Sr, Ba, and Zn are set as M(Sr), M(Ba), and M(Zn), respectively. Furthermore, when M1 is set as M1 = [{C(Sr) / M(Sr)} + ​​{C(Ba) / M(Ba)} + {C(Zn) / M(Zn)}] × 100, from the viewpoint of improving the refractive index, the lower limit of M1 is preferably 9.0, and more preferably in the order of 12.0, 15.0, 18.0, 21.0, and 24.0. From the viewpoint of improving stability during reheating, the upper limit of M1 is preferably 60, and more preferably in the order of 54, 48, 42, 39, and 37.

[0188] In the optical glass of this embodiment, from the viewpoint of increasing the refractive index nd, the lower limit of the total content of Sr and Ba [Sr+Ba] is preferably 2.8 mol%, and more preferably in the order of 3.8 mol%, 4.8 mol%, 5.8 mol%, 6.8 mol%, and 7.8 mol%. From the viewpoint of improving stability upon reheating, the upper limit of this total content is preferably 19.8 mol%, and more preferably in the order of 17.8 mol%, 15.8 mol%, 13.8 mol%, 12.8 mol%, and 11.8 mol%.

[0189] In the optical glass of this embodiment, the contents of Sr and Ba, expressed as mass percent, are set as C(Sr) and C(Ba), respectively, and the atomic weights of Sr, Ba, and Zn are set as M(Sr) and M(Ba), respectively. When M2 is defined as M2 = [{C(Sr) / M(Sr)} + ​​{C(Ba) / M(Ba)}] × 100, from the viewpoint of improving the refractive index, the lower limit of M2 is preferably 8.8, and more preferably in the order of 11.8, 14.8, 17.8, 20.8, and 23.8. From the viewpoint of improving stability during reheating, the upper limit of M2 is preferably 59.8, and more preferably in the order of 53.8, 47.8, 41.8, 38.8, and 36.8.

[0190] In the optical glass of this embodiment, from the viewpoint of improving the meltability of the glass raw material, the upper limit of the La content is preferably 2.0 mol%, and more preferably in the order of 1.6 mol%, 1.2 mol%, 0.8 mol%, and 0.4 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd, the lower limit of the La content is preferably 0 mol%. The La content can be 0 mol%.

[0191] Furthermore, in the optical glass of this embodiment, from the viewpoint of improving the meltability of the glass raw material, the upper limit of the La content is preferably 9.26% by mass, and more preferably in the order of 7.41% by mass, 5.56% by mass, 3.70% by mass, and 1.85% by mass. Additionally, from the viewpoint of maintaining the refractive index nd, the lower limit of the La content is preferably 0% by mass. The La content can be 0% by mass.

[0192] In the glass of this embodiment, from the viewpoint of improving the meltability of the glass raw material, suppressing the rise in raw material costs, and stabilizing the supply of raw materials, the upper limit of the Gd content is preferably 2.0 mol%, and more preferably in the order of 1.6 mol%, 1.2 mol%, 0.8 mol%, and 0.4 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd, the lower limit of the Gd content is preferably 0 mol%. The Gd content can be 0 mol%.

[0193] Furthermore, in the glass of this embodiment, from the viewpoint of improving the meltability of the glass raw material, suppressing the rise in raw material costs, and stabilizing the supply of raw materials, the upper limit of the Gd content is preferably 10.48% by mass, and more preferably in the order of 8.39% by mass, 6.29% by mass, 4.19% by mass, and 2.10% by mass. Additionally, from the viewpoint of maintaining the refractive index nd, the lower limit of the Gd content is preferably 0% by mass. The Gd content can be 0% by mass.

[0194] In the glass of this embodiment, from the viewpoint of increasing the refractive index nd, the lower limit of the Y content is preferably 0 mol%, and more preferably in the order of 0.04 mol%, 0.08 mol%, 0.12 mol%, 0.16 mol%, 0.20 mol%, 0.22 mol%, and 0.24 mol%. Furthermore, from the viewpoint of improving the meltability of the glass raw material, the upper limit of the Y content is preferably 3.0 mol%, and more preferably in the order of 2.4 mol%, 2.0 mol%, 1.6 mol%, 1.2 mol%, 1.0 mol%, 0.8 mol%, 0.6 mol%, and 0.4 mol%.

[0195] Furthermore, in the glass of this embodiment, from the viewpoint of increasing the refractive index nd, the lower limit of the Y content is preferably 0% by mass, and more preferably in the order of 0.11% by mass, 0.22% by mass, 0.32% by mass, 0.43% by mass, 0.54% by mass, 0.59% by mass, and 0.65% by mass. Furthermore, from the viewpoint of improving the meltability of the glass raw material, the upper limit of the Y content is preferably 8.89% by mass, and more preferably in the order of 7.11% by mass, 5.93% by mass, 4.74% by mass, 3.56% by mass, 2.96% by mass, 2.37% by mass, 1.78% by mass, and 1.19% by mass.

[0196] In the glass of this embodiment, from the viewpoint of improving the meltability of the glass raw material, suppressing the rise in raw material costs, and stabilizing the supply of raw materials, the upper limit of the Lu content is preferably 1.6 mol%, and more preferably in the order of 1.2 mol%, 0.8 mol%, 0.4 mol%, and 0.2 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd, the lower limit of the Lu content is preferably 0 mol%. The Lu content can be 0 mol%.

[0197] Furthermore, in the glass of this embodiment, from the viewpoint of improving the meltability of the glass raw material, suppressing the rise in raw material costs, and stabilizing the supply of raw materials, the upper limit of the Lu content is preferably 9.33% by mass, and more preferably in the order of 7.00% by mass, 4.67% by mass, 2.33% by mass, and 1.17% by mass. Additionally, from the viewpoint of maintaining the refractive index nd, the lower limit of the Lu content is preferably 0% by mass. The Lu content can be 0% by mass.

[0198] In the glass of this embodiment, from the viewpoint of improving the meltability of the glass raw material, suppressing the rise in raw material costs, and stabilizing the supply of raw materials, the upper limit of the Yb content is preferably 1.6 mol%, and more preferably in the order of 1.2 mol%, 0.8 mol%, 0.4 mol%, and 0.2 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd, the lower limit of the Yb content is preferably 0 mol%. The Yb content can be 0 mol%.

[0199] Furthermore, in the glass of this embodiment, from the viewpoint of improving the meltability of the glass raw material, suppressing the rise in raw material costs, and stabilizing the supply of raw materials, the upper limit of the Yb content is preferably 9.23% by mass, and more preferably in the order of 6.92% by mass, 4.61% by mass, 2.31% by mass, and 1.15% by mass. Additionally, from the viewpoint of maintaining the refractive index nd, the lower limit of the Yb content is preferably 0% by mass. The Yb content can be 0% by mass.

[0200] In the optical glass of this embodiment, from the viewpoint of suppressing the formation of fluorides with high vapor pressure, thereby suppressing the generation of ribs and maintaining low dispersion, the upper limit of the Nb content is preferably 2.00 mol%, and more preferably in the order of 1.60 mol%, 1.20 mol%, 0.80 mol%, 0.40 mol%, 0.20 mol%, 0.14 mol%, 0.10 mol%, 0.06 mol%, and 0.02 mol%. From the viewpoint of suppressing deviations at the ultraviolet absorption end during manufacturing by setting absorption in the ultraviolet region, the lower limit of the Nb content is preferably 0 mol%, and more preferably in the order of 0.002 mol%, 0.004 mol%, and 0.008 mol%. The Nb content can be 0 mol%.

[0201] Furthermore, in the optical glass of this embodiment, from the viewpoint of suppressing the generation of fluorides with high vapor pressure, thereby suppressing the generation of ribs and maintaining low dispersion, the upper limit of the Nb content is preferably 6.19% by mass, and more preferably in the order of 4.96% by mass, 3.72% by mass, 2.48% by mass, 1.24% by mass, 0.62% by mass, 0.43% by mass, 0.31% by mass, 0.19% by mass, and 0.06% by mass. From the viewpoint of suppressing deviations at the ultraviolet absorption end during manufacturing by setting absorption in the ultraviolet region, the lower limit of the Nb content is preferably 0% by mass, and more preferably in the order of 0.006% by mass, 0.011% by mass, and 0.023% by mass. The Nb content can be 0% by mass.

[0202] In the optical glass of this embodiment, the upper limit of the Ti content is preferably 2.0 mol%, and more preferably in the order of 1.6 mol%, 1.2 mol%, 0.8 mol%, and 0.4 mol%. The lower limit of the Ti content is preferably 0 mol%. The Ti content can be 0 mol%. From the viewpoint of suppressing the formation of fluorides with high vapor pressure, thereby suppressing the generation of ribs and maintaining low dispersion, it is preferable to set the Ti content within the above range.

[0203] Furthermore, in the optical glass of this embodiment, the upper limit of the Ti content is preferably 3.19% by mass, and more preferably in the order of 2.55% by mass, 1.91% by mass, 1.28% by mass, and 0.64% by mass. The lower limit of the Ti content is preferably 0% by mass. The Ti content can be 0% by mass. From the viewpoint of suppressing the formation of fluorides with high vapor pressure, thereby suppressing the generation of ribs and maintaining low dispersion, it is preferable to set the Ti content within the above range.

[0204] In the optical glass of this embodiment, the upper limit of the W content is preferably 2.0 mol%, and more preferably in the order of 1.6 mol%, 1.2 mol%, 0.8 mol%, and 0.4 mol%. The lower limit of the W content is preferably 0 mol%. The W content can be 0 mol%. From the viewpoint of suppressing the generation of fluorides with high vapor pressure, thereby suppressing the generation of ribs and maintaining low dispersion, it is preferable to set the W content within the above range.

[0205] Furthermore, in the optical glass of this embodiment, the upper limit of the W content is preferably 12.26% by mass, and more preferably in the order of 9.80% by mass, 7.35% by mass, 4.90% by mass, and 2.45% by mass. The lower limit of the W content is preferably 0% by mass. The W content can be 0% by mass. From the viewpoint of suppressing the generation of fluorides with high vapor pressure, thereby suppressing the generation of ribs and maintaining low dispersion, it is preferable to set the W content within the above range.

[0206] In the optical glass of this embodiment, the upper limit of the Bi content is preferably 2.0 mol%, and more preferably in the order of 1.6 mol%, 1.2 mol%, 0.8 mol%, and 0.4 mol%. The lower limit of the Bi content is preferably 0 mol%. The Bi content can be 0 mol%. From the viewpoint of suppressing the formation of fluorides with high vapor pressure, thereby suppressing the generation of ribs and maintaining low dispersion, it is preferable to set the Bi content within the above range.

[0207] Furthermore, in the optical glass of this embodiment, the upper limit of the Bi content is preferably 13.93% by mass, and more preferably in the order of 11.15% by mass, 8.36% by mass, 5.57% by mass, and 2.79% by mass. The lower limit of the Bi content is preferably 0% by mass. The Bi content can be 0% by mass. From the viewpoint of suppressing the formation of fluorides with high vapor pressure, thereby suppressing the generation of ribs and maintaining low dispersion, it is preferable to set the Bi content within the above range.

[0208] In the optical glass of this embodiment, from the viewpoint of improving the meltability of the glass raw material, the upper limit of the Zr content is preferably 2.0 mol%, and more preferably in the order of 1.6 mol%, 1.2 mol%, 0.8 mol%, and 0.4 mol%. From the viewpoint of maintaining the refractive index nd, the lower limit of the Zr content is preferably 0 mol%. The Zr content can be 0 mol%.

[0209] Furthermore, in the optical glass of this embodiment, from the viewpoint of improving the meltability of the glass raw material, the upper limit of the Zr content is preferably 6.08% by mass, and more preferably in the order of 4.87% by mass, 3.65% by mass, 2.43% by mass, and 1.22% by mass. From the viewpoint of maintaining the refractive index nd, the lower limit of the Zr content is preferably 0% by mass. The Zr content can be 0% by mass.

[0210] In the optical glass of this embodiment, the upper limit of the Ta content is preferably 2.0 mol%, and more preferably in the order of 1.6 mol%, 1.2 mol%, 0.8 mol%, and 0.4 mol%. The lower limit of the Ta content is preferably 0 mol%. The Ta content can be 0 mol%. From the viewpoint of suppressing the formation of fluorides with high vapor pressure, thereby suppressing the generation of ribs and maintaining low dispersion, it is preferable to set the Ta content within the above range.

[0211] Furthermore, in the optical glass of this embodiment, the upper limit of the Ta content is preferably 12.06% by mass, and more preferably in the order of 9.65% by mass, 7.24% by mass, 4.83% by mass, and 2.41% by mass. The lower limit of the Ta content is preferably 0% by mass. The Ta content can be 0% by mass. From the viewpoint of suppressing the formation of fluorides with high vapor pressure, thereby suppressing the generation of ribs and maintaining low dispersion, it is preferable to set the Ta content within the above range.

[0212] In the glass of this embodiment, the content of Sc is preferably 2 mol% or less. Furthermore, the lower limit of the Sc content is preferably 0 mol%.

[0213] Furthermore, in the glass of this embodiment, the content of Sc is preferably 2.0% by mass or less, more preferably 1.0% by mass or less. Additionally, the lower limit of the Sc content is preferably 0% by mass.

[0214] In the glass of this embodiment, the Hf content is preferably 2 mol% or less. Furthermore, the lower limit of the Hf content is preferably 0 mol%.

[0215] Furthermore, in the glass of this embodiment, the Hf content is preferably 3.0% by mass or less, preferably 1.5% by mass or less, and more preferably 0.8% by mass or less. Additionally, the lower limit of the Hf content is preferably 0% by mass.

[0216] Sc and Hf improve the high dispersibility of glass and are also expensive components. Therefore, the contents of Sc and Hf are preferably within the ranges mentioned above.

[0217] In the glass of this embodiment, the Ge content is preferably 2 mol% or less. Furthermore, the lower limit of the Ge content is preferably 0 mol%.

[0218] Furthermore, in the glass of this embodiment, the Ge content is preferably 2% by mass, and more preferably 1% by mass. Additionally, the lower limit of the Ge content is preferably 0% by mass.

[0219] Ge has the effect of improving the high dispersibility of glass and is a very expensive component in commonly used glass compositions. Therefore, from the viewpoint of reducing glass manufacturing costs, the Ge content is preferably within the range described above.

[0220] The glass in this embodiment preferably consists mainly of the glass composition described above, namely, O, F, P, Al, and Ba as essential components, and B, Si, Li, Na, K, Cs, Mg, Ca, Sr, Zn, La, Gd, Y, Lu, Yb, Nb, Ti, W, Bi, Zr, Ta, Sc, Hf, and Ge as optional components. The total content of the above-mentioned glass components is preferably 95 mol% or more, more preferably 98 mol% or more, further preferably 99 mol% or more, and particularly preferably 99.5 mol% or more. Furthermore, the total content of the above-mentioned glass components is preferably 95 wt% or more, more preferably 98 wt% or more, further preferably 99 wt% or more, and particularly preferably 99.5 wt% or more.

[0221] The glass in this embodiment is preferably composed of the glass composition described above, but it may contain other components without affecting the effectiveness of the invention. Furthermore, the presence of unavoidable impurities is not excluded in this invention.

[0222] In addition to the above-mentioned components, the optical glass may also contain a small amount of Sb or the like as a clarifying agent. The upper limit of the Sb content (added amount) is preferably 0.20 mol%, more preferably in the order of 0.16 mol%, 0.12 mol%, 0.08 mol%, 0.04 mol%, 0.01 mol%, 0.008 mol%, 0.006 mol%, 0.004 mol%, and 0.002 mol%. The lower limit of the Sb content (added amount) is 0 mol%. The Sb content (added amount) can be 0 mol%. Furthermore, the upper limit of the Sb content (added amount) is preferably 0.81 mass%, more preferably in the order of 0.65 mass%, 0.49 mass%, 0.32 mass%, 0.16 mass%, 0.04 mass%, 0.03 mass%, 0.02 mass%, and 0.01 mass%. The lower limit of the Sb content (added amount) is 0 mass. The content of Sb (additional amount) can be 0 by mass.

[0223] The amount of added clarifier refers to the amount of clarifier added, expressed as a molar percentage or mass percentage, when the total content of all glass components other than the clarifier is set to 100%.

[0224] Furthermore, the aforementioned optical glass exhibits high transmittance over a wide visible range. To effectively utilize this advantage, it is preferable to avoid containing coloring elements. Examples of coloring elements include Cu, Co, Ni, Fe, Cr, Eu, Nd, Er, and V. All elements are preferably present in concentrations less than 100 ppm by mass, more preferably 0–80 ppm by mass, even more preferably 0–50 ppm by mass, and most preferably substantially absent.

[0225] Ga, Te, and Tb are components that do not need to be introduced and are also expensive components. Therefore, the contents of Ga, Te, and Tb are preferably 0-0.1 mol%, more preferably 0-0.05 mol%, further preferably 0-0.01 mol%, even more preferably 0-0.005 mol%, and still more preferably 0-0.001 mol%, respectively. In addition, the contents of Ga, Te, and Tb are preferably 0-0.1 mass%, more preferably 0-0.05 mass%, further preferably 0-0.01 mass%, even more preferably 0-0.005 mass%, and still more preferably 0-0.001 mass%, respectively. Particularly preferred is that Ga, Te, and Tb are substantially absent.

[0226] (Glass properties)

[0227] <Abbe number νd>

[0228] In the optical glass of this embodiment, the lower limit of the Abbe number νd is preferably 60.0, but it can also be set to 65.0, 68.0, 68.5, 69.0, 69.5, or 70.0. The upper limit of the Abbe number νd is preferably 94, but it can also be set to 92, 91, 90, 89, 79, 77, 75, 74, 73, or 72. From the viewpoint of improving low dispersion and suppressing the generation of color difference (color bleeding) when combined with high dispersion glass, the lower limit of the Abbe number νd can also be set to 82.0, 83.0, 84.0, or 84.5.

[0229] The Abbe number νd can be adjusted to achieve the desired value by appropriately adjusting the content of each glass component. Components that relatively increase the Abbe number νd, i.e., low-dispersion components, include Si, B, Li, Na, K, La, Ba, Ca, Sr, etc. Conversely, components that relatively decrease the Abbe number νd, i.e., high-dispersion components, include Nb, Ti, Zr, W, Bi, Ta, etc.

[0230] <Refractive index nd>

[0231] In the optical glass of this embodiment, the lower limit of the refractive index nd is preferably 1.30, but it can also be set to 1.35, 1.40, 1.42, 1.43, 1.44, or 1.45. The upper limit of the refractive index nd is preferably 1.65, but it can also be set to 1.62, 1.61, 1.60, 1.59, 1.55, 1.54, 1.53, 1.52, 1.51, or 1.50. From the viewpoint of achieving shorter focal lengths for optical elements by having a high refractive index, while also suppressing aberrations such as image plane curvature, the lower limit of the refractive index nd can also be set to 1.50, 1.51, 1.52, or 1.53.

[0232] The refractive index (nd) can be adjusted to a desired value by appropriately changing the content of each glass component. Components that relatively increase the refractive index (nd) (high refractive index components) include Nb, Ti, Zr, Ta, La, Y, Gd, Ba, Sr, and Zn. On the other hand, components that relatively decrease the refractive index (nd) (low refractive index components) include Si, B, P, Li, Na, K, Mg, and Ca.

[0233] <Stability during reheating>

[0234] The optical glass of this embodiment preferably does not turn cloudy when heated for 10 minutes in a test furnace at a temperature set 130–160°C higher than its glass transition temperature (Tg). More preferably, devitrification is not visible to the naked eye inside the glass; even more preferably, no crystallization is observed inside the glass when viewed under a microscope; and even more preferably, no crystals precipitate inside the glass. The stability during reheating can be controlled by adjusting the molar ratios [O / P], [P / Al], [F / Al], [Ba / P], etc.

[0235] The stability upon reheating was determined as follows. For each dimension (length / width / height) of 10.0 mm ± 5.0 mm, and the sample volume of 512 mm²,... 3 The roughly cuboid glass specimens described above were subjected to primary and secondary heating in the following sequence. The primary and secondary heating were performed using two test furnaces with sufficiently large heat capacities relative to the glass specimens. Hereinafter, each test furnace will be referred to as the primary heating furnace and the secondary heating furnace.

[0236] The aforementioned cuboid-shaped glass sample is placed in a primary heating furnace at a given primary heating temperature. The primary heating is performed under conditions that ensure the glass sample is thoroughly and uniformly heated during the secondary heating process, and that the primary heating does not promote crystallization or the formation of crystal nuclei. Specifically, the lower limit of the primary heating temperature is set to be 20°C lower than the glass transition temperature (Tg) of the glass sample (Tg-20°C), and the upper limit of the primary heating temperature is set to be 15°C higher than the glass transition temperature (Tg) of the glass sample (Tg+15°C). Furthermore, the primary heating time is set to 10–30 minutes.

[0237] After the first heating is completed, the glass sample is removed from the furnace and immediately moved to a secondary heating furnace where it is held at a given secondary heating temperature. The secondary heating temperature is set to be 130–160°C higher than the glass transition temperature (Tg) of the glass sample. The secondary heating time is set to 10 minutes.

[0238] After the second heating, the glass sample was removed from the furnace and allowed to cool naturally to room temperature in the atmosphere. The presence of cloudiness or loss of transparency was then confirmed by visual inspection. Additionally, the interior of the glass was examined under a microscope to confirm the presence of crystallization.

[0239] In both the primary and secondary heating processes, to maintain constant heating conditions for the glass samples placed in the furnace, the samples were positioned in a refractory vessel or base plate and placed in the center of the furnace. It should be noted that the primary and secondary heating temperatures mentioned above refer to the temperatures at the locations where the glass samples were placed. Furthermore, to suppress glass adhesion and heat conduction from the furnace body, thus allowing heating primarily to be achieved through heat transfer from the furnace atmosphere, the glass samples were placed on low-reactivity powders such as boron nitride or alumina. It should be noted that the contact surfaces between these powders and the glass samples were excluded from observation in the stability tests.

[0240] Specific gravity

[0241] In the optical glass of this embodiment, the specific gravity is preferably 4.25 or less, and more preferably 4.20 or less, 4.18 or less, and 4.15 or less in that order. There is no particular limitation on the lower limit of the specific gravity, but it is typically 3.50. The specific gravity is determined by the Archimedes method. The specific gravity tends to increase due to the introduction of elements with large atomic weights, such as Ba, La, Gd, Lu, and Yb, and tends to decrease due to the introduction of elements with small atomic weights, such as Mg and P. On the other hand, the specific gravity also tends to increase by introducing components that contribute to increasing the filling rate of elements in the glass, even with relatively small atomic weights, such as Li and Al. The specific gravity can be controlled by adjusting the content of these components.

[0242] <Glass transition temperature Tg and stabilization index ΔT>

[0243] The stability of the optical glass in this embodiment during reheating can also be evaluated using the stabilization index ΔT described in Reference 2 (Yamane, NEWGLASS No. 7, pp. 19-30 (1987)). Here, Tx is the temperature at which the exothermic peak of crystallization rises, and Tg is the glass transition temperature. ΔT is the difference between Tx and Tg, which can be expressed as ΔT = Tx - Tg. For Tg and Tx, the values ​​can be determined according to the figure disclosed in Reference 2 (…). Figure 1 The numerical value is obtained by parsing.

[0244] In the optical glass of this embodiment, from the viewpoint of reducing the temperature at which the glass is slowly cooled, softened by heating, or pressurized, the glass transition temperature Tg is preferably 550°C or lower, and more preferably 540°C or lower, 535°C or lower, 530°C or lower, and 520°C or lower in that order. There is no particular limitation on the lower limit of the glass transition temperature Tg, but it is typically 380°C. It should be noted that, from the viewpoint of strengthening the glass's network structure to suppress glass breakage, or from the viewpoint of reducing the thermal expansion of the glass and improving its heat resistance, the lower limit of the glass transition temperature Tg is preferably 390°C, and more preferably 400°C, 410°C, 420°C, 430°C, and 440°C or higher in that order. In particular, to minimize the content of phosphorus (F) in high-refractive-index glasses and improve their heat resistance, the lower limit of the glass transition temperature (Tg) is preferably set at 460°C, and more preferably at a rate of 480°C, 500°C, 510°C, 520°C, 530°C, and 535°C or higher. The glass transition temperature (Tg) can be mainly controlled by adjusting the contents of Li, Na, and K, their combined content, the content of F, the content of Zn, the molar ratio [P / Al], and the molar ratio [Ba / P].

[0245] In the optical glass of this embodiment, the stabilization index ΔT, which is the difference between the rising temperature Tx of the exothermic peak of crystallization and the glass transition temperature Tg (Tx-Tg), is preferably 100°C or higher, and more preferably 110°C or higher, 115°C or higher, 120°C or higher, 125°C or higher, and 130°C or higher. Most preferably, no rise of the exothermic peak of crystallization is observed. There is no particular upper limit to the stabilization index ΔT, but it is usually 300°C. ΔT is one of the factors that contributes to the improvement of reheating stability, and can be controlled in approximately the same way as reheating stability by adjusting the molar ratios [O / P], [P / Al], [F / Al], [Ba / P], etc.

[0246] (Manufacturing of optical glass)

[0247] The optical glass of this embodiment is a glass with high refractive index / low dispersion characteristics, that is, a glass with anomalous partial dispersion, and is suitable for all methods of direct pressing, reheat pressing, and precision pressing.

[0248] To obtain the desired glass composition, the optical glass of this embodiment can be obtained as follows: phosphates, fluorides, oxides, etc., as raw materials are weighed and mixed thoroughly to obtain a mixed batch; the batch is then heated and melted in a melting vessel; degassing and stirring are performed to produce a homogeneous molten glass free of bubbles; and then it is shaped. Specifically, a known melting method can be used for manufacturing.

[0249] [Optical component blanks, glass materials for pressing and molding, and their manufacturing methods]

[0250] Another aspect of the present invention relates to:

[0251] An optical element blank, which is made of the aforementioned optical glass;

[0252] A glass material for compression molding, which is made of the aforementioned optical glass;

[0253] A method for manufacturing a glass material for compression molding includes a step of molding the aforementioned optical glass into a glass material for compression molding; and

[0254] A method for manufacturing an optical element blank includes a step of pressing and molding an optical element blank by using a pressing mold while the glass material for pressing and molding has been softened by heating.

[0255] Optical element blanks refer to the base material of optical elements whose shape closely resembles the target optical element, and which incorporates machining allowances such as polishing allowances. Optical elements are completed by polishing the surface of the optical element blank at least once. Optical element blanks can be produced by pressing a glass material made from the aforementioned optical glass, which has been softened by heating, using a pressing mold. The aforementioned optical glass exhibits excellent devitrification resistance, thus preventing crystallization from occurring within the glass due to heating during pressing.

[0256] The heating and pressing of glass materials for compression molding can both be carried out in the atmosphere. For example, if a powdered release agent such as boron nitride is uniformly coated on the surface of the glass material for compression molding and then heated and pressed, not only can the glass be effectively prevented from melting and sticking to the molding die, but the glass can also be smoothly extended along the molding surface of the molding die. By annealing after compression molding to reduce the internal strain of the glass, a homogeneous optical component blank can be obtained.

[0257] On the other hand, the glass material for compression molding, also known as a preform, includes not only the material that is supplied directly for compression molding while maintaining its original state (hereinafter referred to as "raw material 1"), but also the material that is supplied for compression molding through known machining processes (hereinafter referred to as "raw material 2").

[0258] For example, the optical glass described above can be molded into a glass material for compression molding by the method shown in the following example.

[0259] (1) A method for forming a glass plate by casting molten glass into a mold (hereinafter referred to as "Method 1");

[0260] (2) A method for producing multiple glass pieces called fragments by annealing a glass plate made by method 1 and cutting it to the desired size (hereinafter referred to as "method 2").

[0261] (3) A method for tumble polishing of multiple glass plates produced by method 2 (hereinafter referred to as "method 3");

[0262] (4) A method for forming molten glass into a glass block by allowing molten glass to flow down a pipe and be received by a molding die (hereinafter referred to as "method 4");

[0263] (5) A method of annealing the glass block obtained by method 4 and then polishing it with a tumbler (hereinafter referred to as "method 5").

[0264] As raw material 1 mentioned above, examples include glass materials produced by methods 3, 4, and 5. On the other hand, as raw material 2, examples include raw materials produced by methods 1, 2, and 4.

[0265] Optical components and their manufacturing methods

[0266] Another aspect of the present invention relates to:

[0267] An optical element made of the aforementioned optical glass;

[0268] A method for manufacturing an optical element, comprising a step of manufacturing an optical element by polishing the aforementioned optical element blank (hereinafter referred to as "Method A");

[0269] A method for manufacturing an optical element includes a step of precision pressing and molding an optical element using a pressing mold while the glass material for pressing and molding has been softened by heating (hereinafter referred to as "Method B").

[0270] In method A, polishing can be performed using known methods. This can be achieved by thoroughly cleaning and drying the surface of the optical element after processing, resulting in optical elements with high internal and surface quality. Method A is suitable for manufacturing various spherical lenses, prisms, and other optical elements. Alternatively, the optical element blank can be ground using known methods before the polishing process.

[0271] Method B, also known as precision press molding or mold optical molding, is a method of forming the optical functional surfaces of optical elements by transferring the forming surface of a press molding die. Here, the surface that causes light from the optical element to transmit, refract, diffract, or reflect is called the optical functional surface. For example, in the case of lenses, the aspherical surface of an aspherical lens and the spherical surface of a spherical lens are equivalent to optical functional surfaces. Precision press molding forms optical functional surfaces by precisely transferring the forming surface of a press molding die onto glass. In other words, it eliminates the need for machining processes such as grinding and polishing to achieve the optical functional surfaces. Precision press molding is suitable for manufacturing optical elements such as lenses, lens arrays, diffraction gratings, and prisms, and is particularly suitable as a method for highly productive manufacturing of aspherical lenses.

[0272] In one embodiment of the precision pressing molding method, the glass constituting the preform is made to display 10. 5 ~10 11 A preform with a clean surface is reheated using a viscosity range in the Pa·s range. The reheated preform is then pressed into shape using a molding die with an upper and lower mold. A release film can also be provided on the molding surface of the mold, if necessary. It should be noted that, to prevent oxidation of the molding surface of the mold, pressing is preferably performed in a nitrogen or inert gas atmosphere. The pressed product is removed from the mold and slowly cooled as needed. If the molded product is an optical element such as a lens, an optical thin film can be coated onto its surface, if necessary.

[0273] In this way, optical components such as lenses, lens arrays, diffraction gratings, and prisms can be manufactured from optical glass suitable for various molding methods.

[0274] Hereinafter, the first embodiment, the second embodiment, and the third embodiment will be described as preferred embodiments of the present embodiment described above.

[0275] Implementation Method 1

[0276] The first embodiment is one of the preferred embodiments of the present embodiment described above.

[0277] In the first embodiment, in particular, by controlling the ratio of P content to Al content and the ratio of O content to P content, an optical glass is made that ensures a relatively high refractive index and anomalous partial dispersion, while easily suppressing ripples by suppressing the volatilization of glass components and improving stability during reheating.

[0278] As preferred embodiments of the first implementation, embodiments 1-1 and 1-2 are shown.

[0279] Implementation Method 1-1

[0280] Preferably, in the optical glass of the first-1 embodiment,

[0281] The molar ratio of F to Al [F / Al] is 2.70–4.60.

[0282] The molar ratio of Ba to P [Ba / P] is 0.100–1.10.

[0283] The molar ratio of P to Al [P / Al] is 1.50–2.00.

[0284] The molar ratio of O to P [O / P] is 3.55 to 4.00.

[0285] Furthermore, it is preferable that the optical glass in the first-1 embodiment,

[0286] The contents of F, Al, Ba, P and O, expressed as mass percent, are set as C(F), C(Al), C(Ba), C(P) and C(O), respectively.

[0287] Let the atomic weights of F, Al, Ba, P, and O be M(F), M(Al), M(Ba), M(P), and M(O), respectively.

[0288] And set it as:

[0289] A1={C(F) / M(F)} / {C(Al) / M(Al)}

[0290] B1={C(Ba) / M(Ba)} / {C(P) / M(P)}

[0291] C1={C(P) / M(P)} / {C(Al) / M(Al)}

[0292] When D1 = {C(O) / M(O)} / {C(P) / M(P)},

[0293] A1 ranges from 2.70 to 4.60.

[0294] B1 ranges from 0.100 to 1.10.

[0295] C1 is 1.50–2.00.

[0296] D1 is 3.55 to 4.00.

[0297] Implementation Method 1-2

[0298] Preferably, in the optical glass of the first- and second embodiments,

[0299] The molar ratio of F to Al [F / Al] is 2.50–4.60.

[0300] The molar ratio of Ba to P [Ba / P] is 0.250–1.20.

[0301] The molar ratio of P to Al [P / Al] is 1.50–2.00.

[0302] The molar ratio of O to P [O / P] is 3.55 to 3.80.

[0303] Furthermore, it is preferable that the optical glass in the first and second embodiments,

[0304] The contents of F, Al, Ba, P and O, expressed as mass percent, are set as C(F), C(Al), C(Ba), C(P) and C(O), respectively.

[0305] Let the atomic weights of F, Al, Ba, P, and O be M(F), M(Al), M(Ba), M(P), and M(O), respectively.

[0306] And set it as:

[0307] A1={C(F) / M(F)} / {C(Al) / M(Al)}

[0308] B1={C(Ba) / M(Ba)} / {C(P) / M(P)}

[0309] C1={C(P) / M(P)} / {C(Al) / M(Al)}

[0310] When D1 = {C(O) / M(O)} / {C(P) / M(P)},

[0311] A1 ranges from 2.50 to 4.60.

[0312] B1 ranges from 0.250 to 1.20.

[0313] C1 is 1.50–2.00.

[0314] D1 ranges from 3.55 to 3.80.

[0315] The content and ratio of glass components in the optical glass of the first embodiment (the first-1 embodiment and the first-2 embodiment) will be described in detail below.

[0316] In the optical glass of the first embodiment, from the viewpoint of improving stability during reheating, the lower limit of the molar ratio of F content to Al content [F / Al] is preferably 2.50, and more preferably in the order of 2.55, 2.60, 2.65, and 2.70. Furthermore, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the molar ratio [F / Al] is preferably 4.60, and more preferably in the order of 4.50, 4.20, 3.90, 3.60, and 3.40.

[0317] Furthermore, in the optical glass of the first embodiment, when the contents of F and Al expressed as mass percent are set as C(F) and C(Al), respectively, and the atomic weights of F and Al are set as M(F) and M(Al), respectively, and A1 is set as A1 = {C(F) / M(F)} / {C(Al) / M(Al)}, from the viewpoint of improving stability during reheating, the lower limit of A1 is preferably 2.50, and more preferably in the order of 2.55, 2.60, 2.65, and 2.70. Furthermore, from the viewpoint of suppressing the volatilization of glass components, the upper limit of A1 is preferably 4.60, and more preferably in the order of 4.50, 4.20, 3.90, 3.60, and 3.40.

[0318] In the optical glass of the first embodiment, from the viewpoint of improving the refractive index nd, the lower limit of the molar ratio of Ba content to P content [Ba / P] is preferably 0.100, and more preferably in the order of 0.250, 0.700, 0.740, 0.770, 0.790, and 0.800. Furthermore, from the viewpoint of improving stability during reheating, the upper limit of the molar ratio [Ba / P] is preferably 1.20, and more preferably in the order of 1.15, 1.10, 1.05, and 1.00.

[0319] Furthermore, in the optical glass of the first embodiment, when the contents of Ba and P, expressed as mass percent, are set as C(Ba) and C(P), respectively, and the atomic weights of Ba and P are set as M(Ba) and M(P), respectively, and B1 is set as B1 = {C(Ba) / M(Ba)} / {C(P) / M(P)}, from the viewpoint of improving the refractive index nd, the lower limit of B1 is preferably 0.100, and more preferably in the order of 0.250, 0.700, 0.740, 0.770, 0.790, and 0.800. Furthermore, from the viewpoint of improving stability during reheating, the upper limit of B1 is preferably 1.20, and more preferably in the order of 1.15, 1.10, 1.07, 1.05, 1.03, and 1.00.

[0320] In the optical glass of the first embodiment, from the viewpoint of increasing the refractive index nd, the lower limit of the molar ratio of P content to Al content [P / Al] is preferably 1.50, and more preferably in the order of 1.51, 1.52, and 1.53. Furthermore, from the viewpoint of improving stability during reheating, the upper limit of the molar ratio [P / Al] is preferably 2.00, and more preferably in the order of 1.90, 1.85, 1.80, and 1.75.

[0321] Furthermore, in the optical glass of the first embodiment, when the contents of Al and P, expressed as mass percent, are set as C(Al) and C(P), respectively, and the atomic weights of Al and P are set as M(Al) and M(P), respectively, and C1 is set as C1 = {C(P) / M(P)} / {C(Al) / M(Al)}, from the viewpoint of increasing the refractive index nd, the lower limit of C1 is preferably 1.50, and more preferably in the order of 1.51, 1.52, and 1.53. Furthermore, from the viewpoint of improving stability during reheating, the upper limit of C1 is preferably 2.00, and more preferably in the order of 1.90, 1.85, 1.80, and 1.75.

[0322] In the optical glass of the first embodiment, from the viewpoint of suppressing the volatilization of glass components, the lower limit of the molar ratio of O content to P content [O / P] is preferably 3.55, and more preferably in the order of 3.53, 3.55, 3.57, and 3.59. Furthermore, from the viewpoint of improving stability during reheating, the upper limit of the molar ratio [O / P] is preferably 4.00, and more preferably in the order of 3.90, 3.85, 3.82, and 3.80.

[0323] Furthermore, in the optical glass of the first embodiment, when the contents of P and O, expressed as mass percent, are set as C(P) and C(O), respectively, and the atomic weights of P and O are set as M(P) and M(O), respectively, and D1 is set as D1 = {C(O) / M(O)} / {C(P) / M(P)}, from the viewpoint of suppressing the volatilization of glass components, the lower limit of D1 is preferably 3.55, and more preferably in the order of 3.53, 3.55, 3.57, and 3.59. Furthermore, from the viewpoint of improving stability during reheating, the upper limit of D1 is preferably 4.00, and more preferably in the order of 3.90, 3.85, 3.82, and 3.80.

[0324] In the optical glass of the first embodiment, from the viewpoint of improving the refractive index, the lower limit of the molar ratio of the total content of Ba, Sr, and Zn to the content of P [(Ba+Sr+Zn) / P] is preferably 0.700, and more preferably in the order of 0.750, 0.800, 0.850, and 0.900. From the viewpoint of improving stability during reheating, the upper limit of the molar ratio [(Ba+Sr+Zn) / P] is preferably 1.30, and more preferably in the order of 1.25, 1.20, 1.15, and 1.10.

[0325] Furthermore, in the optical glass of the first embodiment, when the contents of P, Sr, Ba, and Zn, expressed as mass percent, are set as C(P), C(Sr), C(Ba), and C(Zn), respectively, and the atomic weights of P, Sr, Ba, and Zn are set as M(P), M(Sr), M(Ba), and M(Zn), respectively, and I1 is set as I1 = [{C(Ba) / M(Ba)} + {C(Sr) / M(Sr)} + ​​{C(Zn) / M(Zn)}] / {C(P) / M(P)}, from the viewpoint of improving the refractive index, the lower limit of I1 is preferably 0.700, and more preferably in the order of 0.750, 0.800, 0.850, and 0.900. From the viewpoint of improving stability during reheating, the upper limit of I1 is preferably 1.30, and more preferably in the order of 1.25, 1.20, 1.15, and 1.10.

[0326] In the optical glass of the first embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the total content of Sr and Li [Sr+Li] is preferably 12 mol%, and more preferably in the order of 10 mol%, 8 mol%, 6 mol%, and 5 mol%. From the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the total content [Sr+Li] is preferably 0 mol%.

[0327] Furthermore, in the optical glass of the first embodiment, when the contents of Li and Sr, expressed as mass percent, are set as C(Li) and C(Sr), respectively, and the atomic weights of Li and Sr are set as M(Li) and M(Sr), respectively, and J1 is set as J1 = [{C(Li) / M(Li)} + {C(Sr) / M(Sr)}] × 100, from the viewpoint of suppressing the volatilization of glass components, the upper limit of J1 is preferably 12, and more preferably in the order of 10, 8, 6, and 5. From the viewpoint of maintaining the meltability of the glass raw material, the lower limit of J1 is preferably 0.

[0328] In the optical glass of the first embodiment, from the viewpoint of improving the meltability of the glass raw materials, the lower limit of the molar ratio of the total content of Ba and Sr to the content of P [(Ba+Sr) / P] is preferably 0.700, and more preferably in the order of 0.740, 0.770, 0.790, and 0.800. Furthermore, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the molar ratio [(Ba+Sr) / P] is preferably 1.20, and more preferably in the order of 1.15, 1.10, 1.05, and 1.00.

[0329] Furthermore, in the optical glass of the first embodiment, when the contents of P, Sr, and Ba, expressed as mass percent, are set as C(P), C(Sr), and C(Ba), respectively, and the atomic weights of P, Sr, and Ba are set as M(P), M(Sr), and M(Ba), respectively, and N1 is set as N1 = [{C(Ba) / M(Ba)} + {C(Sr) / M(Sr)}] / {C(P) / M(P)}, from the viewpoint of improving the meltability of the glass raw material, the lower limit of N1 is preferably 0.700, and more preferably in the order of 0.740, 0.770, 0.790, and 0.800. Furthermore, from the viewpoint of suppressing the volatilization of glass components, the upper limit of N1 is preferably 1.20, and more preferably in the order of 1.15, 1.10, 1.05, and 1.00.

[0330] In the optical glass of the first embodiment, from the viewpoint of suppressing the volatilization of glass components, the lower limit of the O content is preferably 30 mol%, and more preferably in the order of 33 mol%, 35 mol%, 36 mol%, 37 mol%, and 38 mol%. From the viewpoint of improving stability during reheating, the upper limit of the O content is preferably 60 mol%, and more preferably in the order of 56 mol%, 52 mol%, 50 mol%, 49 mol%, and 48 mol%.

[0331] Furthermore, in the optical glass of the first embodiment, from the viewpoint of suppressing the volatilization of glass components, the lower limit of the O content is preferably 16.00% by mass, and more preferably in the order of 17.60% by mass, 18.67% by mass, 19.2% by mass, 19.73% by mass, and 20.27% by mass. From the viewpoint of improving stability during reheating, the upper limit of the O content is preferably 29.09% by mass, and more preferably in the order of 27.15% by mass, 25.21% by mass, 24.24% by mass, 23.76% by mass, and 23.27% by mass.

[0332] In the optical glass of the first embodiment, from the viewpoint of improving stability upon reheating, the lower limit of the F content is preferably 8 mol%, and more preferably in the order of 11 mol%, 14 mol%, 16 mol%, 17 mol%, and 18 mol%. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the F content is preferably 35 mol%, and more preferably in the order of 33 mol%, 31 mol%, 29 mol%, 28 mol%, and 27 mol%.

[0333] Furthermore, in the optical glass of the first embodiment, from the viewpoint of improving stability during reheating, the lower limit of the F content is preferably 5.07% by mass, and more preferably in the order of 6.97% by mass, 8.87% by mass, 10.13% by mass, 10.77% by mass, and 11.40% by mass. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the F content is preferably 20.15% by mass, and more preferably in the order of 19.00% by mass, 17.85% by mass, 16.70% by mass, 16.12% by mass, and 15.54% by mass.

[0334] In the optical glass of the first embodiment, from the viewpoint of improving stability during reheating, the lower limit of the P content is preferably 2.0 mol%, and more preferably in the order of 4.0 mol%, 6.0 mol%, 8.0 mol%, and 9.0 mol%. Furthermore, from the viewpoint of improving the refractive index nd, the upper limit of the P content is preferably 25 mol%, and more preferably in the order of 22 mol%, 18 mol%, 15 mol%, 14 mol%, and 13 mol%.

[0335] Furthermore, in the optical glass of the first embodiment, from the viewpoint of improving stability during reheating, the lower limit of the P content is preferably 2.10% by mass, and more preferably in the order of 4.13% by mass, 6.19% by mass, 8.26% by mass, and 9.29% by mass. Furthermore, from the viewpoint of improving the refractive index nd, the upper limit of the P content is preferably 23.46% by mass, and more preferably in the order of 20.65% by mass, 16.89% by mass, 14.08% by mass, 13.14% by mass, and 12.20% by mass.

[0336] In the optical glass of the first embodiment, from the viewpoint of improving chemical durability, the lower limit of the Al content is preferably 1.0 mol%, and more preferably in the order of 2.0 mol%, 3.0 mol%, 4.0 mol%, and 5.0 mol%. Furthermore, from the viewpoint of improving stability upon reheating, the upper limit of the Al content is preferably 18 mol%, and more preferably in the order of 12 mol%, 11 mol%, 10 mol%, and 9 mol%.

[0337] Furthermore, in the optical glass of the first embodiment, from the viewpoint of improving chemical durability, the lower limit of the Al content is preferably 0.9% by mass, and more preferably in the order of 1.8% by mass, 2.7% by mass, 3.6% by mass, and 4.5% by mass. Furthermore, from the viewpoint of improving stability upon reheating, the upper limit of the Al content is preferably 14.72% by mass, and more preferably in the order of 12.26% by mass, 9.81% by mass, 8.99% by mass, 8.18% by mass, and 7.36% by mass.

[0338] In the optical glass of the first embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the content of B is preferably 10 mol%, and more preferably in the order of 8 mol%, 6 mol%, 4 mol%, 3 mol%, and 2 mol%. Furthermore, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the content of B is preferably 0 mol%. The content of B can be 0 mol%.

[0339] Furthermore, in the optical glass of the first embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the B content is preferably 3.28% by mass, and more preferably in the order of 2.62% by mass, 1.97% by mass, 1.31% by mass, 0.98% by mass, and 0.66% by mass. Additionally, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the B content is preferably 0% by mass. The B content can be 0% by mass.

[0340] In the glass of the first embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Li content is preferably 10 mol%, and more preferably in the order of 8 mol%, 6 mol%, 4 mol%, 3 mol%, and 2 mol%. Furthermore, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the Li content is preferably 0 mol%.

[0341] Furthermore, in the glass of the first embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Li content is preferably 2.10% by mass, and more preferably in the order of 1.68% by mass, 1.26% by mass, 0.84% ​​by mass, 0.63% by mass, and 0.42% by mass. Additionally, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the Li content is preferably 0% by mass.

[0342] In the glass of the first embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Na content is preferably 10 mol%, and more preferably in the order of 8 mol%, 6 mol%, 4 mol%, 3 mol%, and 2 mol%. Furthermore, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the Na content is preferably 0 mol%. The Na content can be 0 mol%.

[0343] Furthermore, in the glass of the first embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Na content is preferably 6.97% by mass, and more preferably in the order of 5.57% by mass, 4.18% by mass, 2.79% by mass, 2.09% by mass, and 1.39% by mass. Additionally, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the Na content is preferably 0% by mass. The Na content can be 0% by mass.

[0344] In the optical glass of the first embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the K content is preferably 10 mol%, and more preferably in the order of 8 mol%, 6 mol%, 4 mol%, 3 mol%, and 2 mol%. From the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the K content is preferably 0 mol%. The K content can be 0 mol%.

[0345] Furthermore, in the optical glass of the first embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the K content is preferably 11.85% by mass, and more preferably in the order of 9.48% by mass, 7.11% by mass, 4.74% by mass, 3.55% by mass, and 2.37% by mass. From the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the K content is preferably 0% by mass. The K content can be 0% by mass.

[0346] Furthermore, in the optical glass of the first embodiment, from the viewpoint of improving resistance to devitrification during melting, the upper limit of the Mg content is preferably 10 mol%, and more preferably in the order of 8 mol%, 6 mol%, 4 mol%, 3 mol%, and 2 mol%. From the viewpoint of maintaining stability during reheating, the lower limit of the Mg content is preferably 0 mol%.

[0347] Furthermore, in the optical glass of the first embodiment, from the viewpoint of improving resistance to devitrification during melting, the upper limit of the Mg content is preferably 7.37% by mass, and more preferably in the order of 5.89% by mass, 4.42% by mass, 2.95% by mass, and 2.21% by mass. From the viewpoint of maintaining stability during reheating, the lower limit of the Mg content is preferably 0% by mass.

[0348] In the optical glass of the first embodiment, from the viewpoint of improving resistance to devitrification during melting, the upper limit of the Ca content is preferably 10 mol%, and more preferably in the order of 8 mol%, 6 mol%, 4 mol%, 3 mol%, and 2 mol%. Furthermore, from the viewpoint of maintaining stability during reheating, the lower limit of the Ca content is preferably 0 mol%.

[0349] Furthermore, in the optical glass of the first embodiment, from the viewpoint of improving resistance to devitrification during melting, the upper limit of the Ca content is preferably 12.14% by mass, and more preferably in the order of 9.72% by mass, 7.29% by mass, 4.86% by mass, and 3.64% by mass. Additionally, from the viewpoint of maintaining stability during reheating, the lower limit of the Ca content is preferably 0% by mass.

[0350] In the optical glass of the first embodiment, from the viewpoint of improving resistance to devitrification during melting, the upper limit of the Sr content is preferably 10 mol%, and more preferably in the order of 8 mol%, 6 mol%, 4 mol%, 3 mol%, and 2 mol%. Furthermore, from the viewpoint of maintaining stability during reheating, the lower limit of the Sr content is preferably 0 mol%.

[0351] Furthermore, in the optical glass of the first embodiment, from the viewpoint of improving resistance to devitrification during melting, the upper limit of the Sr content is preferably 26.55% by mass, and more preferably in the order of 21.24% by mass, 15.93% by mass, 10.62% by mass, and 5.31% by mass. Additionally, from the viewpoint of maintaining stability during reheating, the lower limit of the Sr content is preferably 0% by mass.

[0352] In the optical glass of the first embodiment, from the viewpoint of increasing the refractive index nd, the lower limit of the Ba content is preferably 1 mol%, and more preferably in the order of 3 mol%, 5 mol%, 7 mol%, and 8 mol%. From the viewpoint of improving stability during reheating, the upper limit of the Ba content is preferably 20 mol%, and more preferably in the order of 18 mol%, 16 mol%, 14 mol%, 13 mol%, and 12 mol%.

[0353] Furthermore, in the optical glass of the first embodiment, from the viewpoint of increasing the refractive index nd, the lower limit of the Ba content is preferably 4.58% by mass, and more preferably in the order of 13.73% by mass, 22.89% by mass, 32.04% by mass, and 36.62% by mass. From the viewpoint of improving stability during reheating, the upper limit of the Ba content is preferably 83.23% by mass, and more preferably in the order of 74.91% by mass, 66.58% by mass, 58.26% by mass, 54.1% by mass, and 49.94% by mass.

[0354] In the optical glass of the first embodiment, from the viewpoint of improving the meltability of the glass raw material, the upper limit of the Zn content is preferably 10 mol%, and more preferably in the order of 8 mol%, 6 mol%, 4 mol%, 3 mol%, and 2 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd, the lower limit of the Zn content is preferably 0 mol%. The Zn content can be 0 mol%.

[0355] Furthermore, in the optical glass of the first embodiment, from the viewpoint of improving the meltability of the glass raw material, the upper limit of the Zn content is preferably 19.82% by mass, and more preferably in the order of 15.86% by mass, 11.89% by mass, 7.93% by mass, 5.95% by mass, and 3.96% by mass. Additionally, from the viewpoint of maintaining the refractive index nd, the lower limit of the Zn content is preferably 0% by mass. The Zn content can be 0% by mass.

[0356] In the optical glass of the first embodiment, from the viewpoint of improving the meltability of the glass raw material, the upper limit of the La content is preferably 8 mol%, and more preferably in the order of 6 mol%, 4 mol%, 3 mol%, 2 mol%, and 1 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd, the lower limit of the La content is preferably 0 mol%. The La content can be 0 mol%.

[0357] Furthermore, in the optical glass of the first embodiment, from the viewpoint of improving the meltability of the glass raw material, the upper limit of the La content is preferably 33.67% by mass, and more preferably in the order of 25.26% by mass, 16.84% by mass, 12.63% by mass, 8.42% by mass, and 4.21% by mass. Additionally, from the viewpoint of maintaining the refractive index nd, the lower limit of the La content is preferably 0% by mass. The La content can be 0% by mass.

[0358] In the glass of the first embodiment, from the viewpoint of improving the meltability of the glass raw material, suppressing the rise in raw material costs, and stabilizing the supply of raw materials, the upper limit of the Gd content is preferably 4.0 mol%, and more preferably in the order of 3.2 mol%, 1.6 mol%, 0.8 mol%, 0.4 mol%, and 0.2 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd, the lower limit of the Gd content is preferably 0 mol%. The Gd content can be 0 mol%.

[0359] Furthermore, in the glass of the first embodiment, from the viewpoint of improving the meltability of the glass raw material, suppressing the rise in raw material costs, and stabilizing the supply of raw materials, the upper limit of the Gd content is preferably 19.06% by mass, and more preferably in the order of 15.25% by mass, 7.62% by mass, 3.81% by mass, 1.91% by mass, and 0.95% by mass. Additionally, from the viewpoint of maintaining the refractive index nd, the lower limit of the Gd content is preferably 0% by mass. The Gd content can be 0% by mass.

[0360] In the glass of the first embodiment, from the viewpoint of improving the meltability of the glass raw material, the upper limit of the Y content is preferably 8 mol%, and more preferably in the order of 6 mol%, 4 mol%, 3 mol%, 2 mol%, and 1 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd, the lower limit of the Y content is preferably 0 mol%.

[0361] Furthermore, in the glass of the first embodiment, from the viewpoint of improving the meltability of the glass raw material, the upper limit of the Y content is preferably 21.55% by mass, and more preferably in the order of 16.16% by mass, 10.78% by mass, 8.08% by mass, 5.39% by mass, and 2.69% by mass. Furthermore, from the viewpoint of maintaining the refractive index nd, the lower limit of the Y content is preferably 0% by mass.

[0362] In the glass of the first embodiment, from the viewpoint of improving the meltability of the glass raw material, suppressing the rise in raw material costs, and stabilizing the supply of raw materials, the upper limit of the Lu content is preferably 4.0 mol%, and more preferably in the order of 3.0 mol%, 2.0 mol%, 1.0 mol%, 0.5 mol%, and 0.2 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd, the lower limit of the Lu content is preferably 0 mol%. The Lu content can be 0 mol%.

[0363] Furthermore, in the glass of the first embodiment, from the viewpoint of improving the meltability of the glass raw material, suppressing the rise in raw material costs, and stabilizing the supply of raw materials, the upper limit of the Lu content is preferably 21.21% by mass, and more preferably in the order of 15.91% by mass, 10.6% by mass, 5.3% by mass, 2.65% by mass, and 1.06% by mass. Furthermore, from the viewpoint of maintaining the refractive index nd, the lower limit of the Lu content is preferably 0% by mass. The Lu content can be 0% by mass.

[0364] In the glass of the first embodiment, from the viewpoint of improving the meltability of the glass raw material, suppressing the rise in raw material costs, and stabilizing the supply of raw materials, the upper limit of the Yb content is preferably 4.0 mol%, and more preferably in the order of 3.0 mol%, 2.0 mol%, 1.0 mol%, 0.5 mol%, and 0.2 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd, the lower limit of the Yb content is preferably 0 mol%. The Yb content can be 0 mol%.

[0365] Furthermore, in the glass of the first embodiment, from the viewpoint of improving the meltability of the glass raw material, suppressing the rise in raw material costs, and stabilizing the supply of raw materials, the upper limit of the Yb content is preferably 20.97% by mass, and more preferably in the order of 15.73% by mass, 10.49% by mass, 5.24% by mass, 2.62% by mass, and 1.05% by mass. Additionally, from the viewpoint of maintaining the refractive index nd, the lower limit of the Yb content is preferably 0% by mass. The Yb content can be 0% by mass.

[0366] In the optical glass of the first embodiment, from the viewpoint of suppressing the generation of fluorides with high vapor pressure, thereby suppressing the generation of ribs and maintaining low dispersion, the upper limit of the Nb content is preferably 0.90 mol%, and more preferably in the order of 0.40 mol%, 0.20 mol%, 0.09 mol%, 0.04 mol%, and 0.02 mol%. From the viewpoint of suppressing deviations at the ultraviolet absorption end during manufacturing by setting absorption in the ultraviolet region, the lower limit of the Nb content is preferably 0 mol%, and more preferably in the order of 0.001 mol%, 0.003 mol%, 0.005 mol%, 0.007 mol%, and 0.009 mol%. The Nb content can be 0 mol%.

[0367] Furthermore, in the optical glass of the first embodiment, from the viewpoint of suppressing the generation of fluorides with high vapor pressure, thereby suppressing the generation of ribs and maintaining low dispersion, the upper limit of the Nb content is preferably 2.53% by mass, and more preferably in the order of 1.13% by mass, 0.56% by mass, 0.25% by mass, 0.11% by mass, and 0.06% by mass. From the viewpoint of suppressing deviations at the ultraviolet absorption end during manufacturing by setting absorption in the ultraviolet region, the lower limit of the Nb content is preferably 0% by mass, and more preferably in the order of 0.01% by mass, 0.02% by mass, and 0.03% by mass. The Nb content can be 0% by mass.

[0368] In the optical glass of the first embodiment, from the viewpoint of improving the meltability of the glass raw material, the upper limit of the Zr content is preferably 10 mol%, and more preferably in the order of 8 mol%, 6 mol%, 4 mol%, 3 mol%, and 2 mol%. From the viewpoint of maintaining the refractive index nd, the lower limit of the Zr content is preferably 0 mol%. The Zr content can be 0 mol%.

[0369] Furthermore, in the optical glass of the first embodiment, from the viewpoint of improving the meltability of the glass raw material, the upper limit of the Zr content is preferably 1.0% by mass, and more preferably in the order of 0.5% by mass, 0.2% by mass, and 0.1% by mass. From the viewpoint of maintaining the refractive index nd, the lower limit of the Zr content is preferably 0% by mass. The Zr content can be 0% by mass.

[0370] In the optical glass of the first embodiment, the content and ratio of glass components other than those described above can be the same as in this embodiment.

[0371] In the optical glass of the first embodiment, the glass properties can be the same as those of this embodiment described above.

[0372] The manufacturing of optical glass, optical element blanks, and optical elements in the first embodiment can also be the same as in this embodiment described above.

[0373] Implementation Method 2

[0374] The second embodiment is one of the preferred embodiments of the present embodiment described above.

[0375] In the second embodiment, in particular, by controlling the ratio of F content to Al content to a high level, an optical glass is made that improves low dispersion, ensures aberrant partial dispersion, easily suppresses ripples by suppressing the volatilization of glass components, and improves stability during reheating.

[0376] As a preferred embodiment of the second embodiment, embodiments 2-1 and 2-2 are shown.

[0377] Implementation Method 2-1

[0378] Preferably, in the optical glass of the second-1 embodiment,

[0379] The molar ratio of F to Al [F / Al] is 4.60–15.0.

[0380] The molar ratio of Ba to P [Ba / P] is 0.100–1.20.

[0381] The molar ratio of P to Al [P / Al] is 0.200–0.900.

[0382] The molar ratio of O to P [O / P] is 3.60–4.20.

[0383] The molar ratio of F content to the total content of O, F, and Cl [F / (O+F+Cl)] is 0.010–0.790.

[0384] The molar ratio of the total content of Sr and Ba to the total content of Mg, Ca, Sr, Ba and Zn [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] is 0.00 to 0.67.

[0385] Furthermore, it is preferable that the optical glass in the second-first embodiment,

[0386] The contents of F, Al, Ba, P, O, Cl, Mg, Ca, Sr, Ba, and Zn, expressed as mass percent, are respectively set as C(F), C(Al), C(Ba), C(P), C(O), C(Cl), C(Mg), C(Ca), C(Sr), C(Ba), and C(Zn).

[0387] Let the atomic weights of F, Al, Ba, P, O, Cl, Mg, Ca, Sr, Ba, and Zn be M(F), M(Al), M(Ba), M(P), M(O), M(Cl), M(Mg), M(Ca), M(Sr), M(Ba), and M(Zn), respectively.

[0388] And set it as:

[0389] A1={C(F) / M(F)} / {C(Al) / M(Al)}

[0390] B1={C(Ba) / M(Ba)} / {C(P) / M(P)}

[0391] C1={C(P) / M(P)} / {C(Al) / M(Al)}

[0392] D1 = {C(O) / M(O)} / {C(P) / M(P)}

[0393] G1=[{C(F) / M(F)} / [{C(O) / M(O)}+{C(F) / M(F)}+{C(Cl) / M(Cl)}]]

[0394] When H1=[{C(Sr) / M(Sr)}+{C(Ba) / M(Ba)}] / [{C(Mg) / M(Mg)}+{C(Ca) / M(Ca)}+{C(Sr) / M(Sr)}+{C(Ba) / M(Ba)}+{C(Zn) / M(Zn)}],

[0395] A1 ranges from 4.60 to 15.0.

[0396] B1 ranges from 0.100 to 1.20.

[0397] C1 ranges from 0.200 to 0.900.

[0398] D1 ranges from 3.60 to 4.20.

[0399] G1 ranges from 0.010 to 0.790.

[0400] H1 ranges from 0.00 to 0.67.

[0401] Implementation Method 2-2

[0402] Preferably, in the optical glass of the second-2nd embodiment,

[0403] The molar ratio of F to Al [F / Al] is 4.60–15.0.

[0404] The molar ratio of Ba to P [Ba / P] is 0.100–1.20.

[0405] The molar ratio of P to Al [P / Al] is 0.200–0.900.

[0406] The molar ratio of O to P [O / P] is 3.60–4.20.

[0407] The molar ratio of F content to the total content of O, F and Cl [F / (O+F+Cl)] is 0.010 to 0.790, and the total content of Li, Na and K [Li+Na+K] is 0.00 to 5.00 mol%.

[0408] Furthermore, in the optical glass of the second-2nd embodiment, it is preferable that...

[0409] The contents of F, Al, Ba, P, O, Cl, Li, Na, and K, expressed as mass percent, are respectively set as C(F), C(Al), C(Ba), C(P), C(O), C(Cl), C(Li), C(Na), and C(K).

[0410] Let the atomic weights of F, Al, Ba, P, O, Cl, Li, Na, and K be M(F), M(Al), M(Ba), M(P), M(O), M(Cl), M(Li), M(Na), and M(K), respectively.

[0411] And set it as:

[0412] A1={C(F) / M(F)} / {C(Al) / M(Al)}

[0413] B1={C(Ba) / M(Ba)} / {C(P) / M(P)}

[0414] C1={C(P) / M(P)} / {C(Al) / M(Al)}

[0415] D1 = {C(O) / M(O)} / {C(P) / M(P)}

[0416] G1=[{C(F) / M(F)} / [{C(O) / M(O)}+{C(F) / M(F)}+{C(Cl) / M(Cl)}]]

[0417] When F1=[{C(Li) / M(Li)}+{C(Na) / M(Na)}+{C(K) / M(K)}]×100,

[0418] A1 ranges from 4.60 to 15.0.

[0419] B1 ranges from 0.100 to 1.20.

[0420] C1 ranges from 0.200 to 0.900.

[0421] D1 ranges from 3.60 to 4.20.

[0422] G1 ranges from 0.010 to 0.79.

[0423] F1 ranges from 0.0 to 5.0.

[0424] The content and ratio of glass components in the optical glass of the second embodiment (the second-1st embodiment and the second-2nd embodiment) will be described in detail below.

[0425] In the optical glass of the second embodiment, from the viewpoint of improving stability during reheating, the lower limit of the molar ratio of F content to Al content [F / Al] is preferably 4.60, and more preferably in the order of 4.65, 4.70, 4.75, and 4.80. Furthermore, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the molar ratio [F / Al] is preferably 15.0, and more preferably in the order of 10.0, 8.0, 7.0, and 6.5.

[0426] Furthermore, in the optical glass of the second embodiment, when the contents of F and Al expressed as mass percent are set as C(F) and C(Al), respectively, and the atomic weights of F and Al are set as M(F) and M(Al), respectively, and A1 is set as A1 = {C(F) / M(F)} / {C(Al) / M(Al)}, from the viewpoint of improving stability during reheating, the lower limit of A1 is preferably 4.60, and more preferably in the order of 4.65, 4.70, 4.75, and 4.80. Furthermore, from the viewpoint of suppressing the volatilization of glass components, the upper limit of A1 is preferably 15.0, and more preferably in the order of 10.0, 8.0, 7.0, and 6.5.

[0427] In the optical glass of the second embodiment, from the viewpoint of improving the refractive index nd, the lower limit of the molar ratio of Ba content to P content [Ba / P] is preferably 0.100, and more preferably in the order of 0.350, 0.400, 0.450, and 0.500. Furthermore, from the viewpoint of improving stability during reheating, the upper limit of the molar ratio [Ba / P] is preferably 1.20, and more preferably in the order of 1.10, 1.08, 1.06, and 1.05.

[0428] Furthermore, in the optical glass of the second embodiment, when the contents of Ba and P, expressed as mass percent, are set as C(Ba) and C(P), respectively, and the atomic weights of Ba and P are set as M(Ba) and M(P), respectively, and B1 is set as B1 = {C(Ba) / M(Ba)} / {C(P) / M(P)}, from the viewpoint of improving the refractive index nd, the lower limit of B1 is preferably 0.100, and more preferably in the order of 0.350, 0.400, 0.450, and 0.500. Furthermore, from the viewpoint of improving stability during reheating, the upper limit of B1 is preferably 1.50, and more preferably in the order of 1.10, 1.08, 1.06, and 1.05.

[0429] In the optical glass of the second embodiment, from the viewpoint of high refractive index and low dispersion, the upper limit of the molar ratio of P content to Al content [P / Al] is preferably 0.900, and more preferably in the order of 0.800 and 0.700. Furthermore, from the viewpoint of improving resistance to devitrification during melting and stability during reheating, the lower limit of the molar ratio [P / Al] is preferably 0.200, and more preferably in the order of 0.250, 0.300, and 0.350.

[0430] Furthermore, in the optical glass of the second embodiment, when the contents of Al and P, expressed as mass percent, are set as C(Al) and C(P), respectively, and the atomic weights of Al and P are set as M(Al) and M(P), respectively, and C1 is set as C1 = {C(P) / M(P)} / {C(Al) / M(Al)}, from the viewpoint of high refractive index and low dispersion, the upper limit of C1 is preferably 0.900, and more preferably in the order of 0.800 and 0.700. Furthermore, from the viewpoint of improving resistance to devitrification during melting and stability during reheating, the lower limit of C1 is preferably 0.200, and more preferably in the order of 0.250, 0.300, and 0.350.

[0431] In the optical glass of the second embodiment, from the viewpoint of suppressing the volatilization of glass components, the lower limit of the molar ratio of O content to P content [O / P] is preferably 3.60, and more preferably in the order of 3.62, 3.64, and 3.66. Furthermore, from the viewpoint of improving stability during molding and reheating, the upper limit of the molar ratio [O / P] is preferably 4.20, and more preferably in the order of 4.10, 4.00, and 3.95.

[0432] Furthermore, in the optical glass of the second embodiment, when the contents of P and O, expressed as mass percent, are set as C(P) and C(O), respectively, and the atomic weights of P and O are set as M(P) and M(O), respectively, and D1 is set as D1 = {C(O) / M(O)} / {C(P) / M(P)}, from the viewpoint of suppressing the volatilization of glass components, the lower limit of D1 is preferably 3.60, and more preferably in the order of 3.62, 3.64, and 3.66. Furthermore, from the viewpoint of improving stability during molding and reheating, the upper limit of D1 is preferably 4.20, and more preferably in the order of 4.10, 4.00, and 3.95.

[0433] In the optical glass of the second embodiment, from the viewpoint of improving low dispersion and anomalous partial dispersion, the lower limit of the molar ratio of F content to the total content of O, F and Cl [F / (O+F+Cl)] is preferably 0.010, and more preferably in the order of 0.160, 0.220, 0.250, 0.280, 0.30, 0.320, 0.420, 0.450, 0.50, 0.550, 0.600, 0.625 and 0.650. From the viewpoint of improving the stability of glass and suppressing volatilization, the upper limit of the molar ratio [F / (O+F+Cl)] is preferably 0.940, and further preferred in the order of 0.890, 0.850, 0.820, 0.810, 0.800, 0.790, 0.780, 0.770, 0.760, 0.750, and 0.710.

[0434] Furthermore, in the optical glass of the second embodiment, the contents of F, O, and Cl expressed in mass percent are set as C(F), C(O), and C(Cl), respectively, and the atomic weights of F, O, and Cl are set as M(F), M(O), and M(Cl), respectively. When G1 is set as G1 = [{C(F) / M(F)} / [{C(O) / M(O)}+{C(F) / M(F)}+{C(Cl) / M(Cl)}]], from the viewpoint of improving low dispersion and anomalous partial dispersion, the lower limit of G1 is preferably 0.010, and more preferably in the order of 0.110, 0.160, 0.220, 0.250, 0.280, 0.30, 0.320, 0.40, 0.420, 0.450, 0.50, 0.550, 0.600, 0.625, and 0.650. From the viewpoint of improving stability during reheating and suppressing the volatilization of glass components, the upper limit of G1 is preferably 0.940, and further preferred in the order of 0.890, 0.850, 0.820, 0.810, 0.800, 0.790, 0.780, 0.770, 0.760, 0.750, and 0.710.

[0435] In the optical glass of the second embodiment, from the viewpoint of improving the refractive index nd, the lower limit of the molar ratio of the total content of Sr and Ba to the total content of Mg, Ca, Sr, Ba and Zn [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] is preferably 0.00, and more preferably in the order of 0.300, 0.350, 0.400, 0.450, and 0.500. From the viewpoint of improving stability during reheating, the upper limit of the molar ratio [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] is preferably 0.67, and more preferably in the order of 0.667, 0.650, 0.640, 0.630, and 0.620.

[0436] Furthermore, in the optical glass of the second embodiment, the contents of Mg, Ca, Sr, Ba, and Zn, expressed as mass percent, are set as C(Mg), C(Ca), C(Sr), C(Ba), and C(Zn), respectively; the atomic weights of Mg, Ca, Sr, Ba, and Zn are set as M(Mg), M(Ca), M(Sr), M(Ba), and M(Zn), respectively; and H1 is set as H1 = [{C(Sr) / M(Sr)} + ​​{C When H1 is [{C(Mg) / M(Mg)}+{C(Ca) / M(Ca)}+{C(Sr) / M(Sr)}+{C(Ba) / M(Ba)}+{C(Zn) / M(Zn)}], from the viewpoint of increasing the refractive index nd, the lower limit of H1 is preferably 0.00, and more preferably in the order of 0.300, 0.350, 0.400, 0.450, and 0.500. From the viewpoint of improving stability during reheating, the upper limit of H1 is preferably 0.67, and more preferably in the order of 0.667, 0.650, 0.640, 0.630, and 0.620.

[0437] In the optical glass of the second embodiment, from the viewpoint of improving the meltability of the glass raw materials, the lower limit of the total content of Li, Na, and K [Li+Na+K] is preferably 0.00 mol%, and more preferably in the order of 0.20 mol%, 0.40 mol%, and 0.60 mol%. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the total content [Li+Na+K] is preferably 6.50 mol%, and more preferably in the order of 6.00 mol%, 5.50 mol%, and 5.00 mol%.

[0438] In the optical glass of the second embodiment, the contents of Li, Na, and K, expressed as mass percent, are set as C(Li), C(Na), and C(K), respectively, and the atomic weights of Li, Na, and K are set as M(Li), M(Na), and M(K), respectively. When F1 is set as F1 = [{C(Li) / M(Li)} + {C(Na) / M(Na)} + {C(K) / M(K)}] × 100, from the viewpoint of improving the meltability of the glass raw material, the lower limit of F1 is preferably 0, and more preferably in the order of 0.6, 1.2, and 1.8. From the viewpoint of suppressing the volatilization of glass components, the upper limit of F1 is preferably 19.5, and more preferably in the order of 18.0, 16.5, and 15.0.

[0439] In the optical glass of the second embodiment, from the viewpoint of improving the refractive index nd and improving chemical durability, the lower limit of the total content of Y, La, Gd, Yb and Lu [Y+La+Gd+Yb+Lu] is preferably 0.0 mol%, and more preferably in the order of 0.05 mol%, 0.10 mol%, and 0.15 mol%. From the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the upper limit of the total content [Y+La+Gd+Yb+Lu] is preferably 1.62 mol%, and more preferably in the order of 1.40 mol%, 1.20 mol%, and 1.00 mol%.

[0440] Furthermore, in the optical glass of the second embodiment, the contents of Y, La, Gd, Yb, and Lu, expressed as mass percent, are set as C(Y), C(La), C(Gd), C(Yb), and C(Lu), respectively, and the atomic weights of Y, La, Gd, Yb, and Lu are set as M(Y), M(La), M(Gd), M(Yb), and M(Lu), respectively. When K1 = [{C(Y) / M(Y)} + {C(La) / M(La)} + {C(Gd) / M(Gd)} + {C(Yb) / M(Yb)} + {C(Lu) / M(Lu)}] × 100, from the viewpoint of increasing the refractive index nd and improving chemical durability, the lower limit of K1 is preferably 0, and more preferably in the order of 0.15, 0.30, and 0.45. From the viewpoint of improving the meltability of glass raw materials and improving the resistance to devitrification during melting, the upper limit of K1 is preferably 4.86, and more preferably in the order of 4.20, 3.60 and 3.00.

[0441] In the optical glass of the second embodiment, from the viewpoint of improving the refractive index nd, the lower limit of the molar ratio of the total content of Ba and Sr to the content of P [(Ba+Sr) / P] is preferably 1.05, and more preferably in the order of 1.15, 1.25, 1.35, and 1.45. Furthermore, from the viewpoint of improving stability during reheating, the upper limit of the molar ratio [(Ba+Sr) / P] is preferably 2.25, and more preferably in the order of 2.15, 2.05, 1.95, and 1.85.

[0442] Furthermore, in the optical glass of the second embodiment, when the contents of P, Sr, and Ba, expressed as mass percent, are set as C(P), C(Sr), and C(Ba), respectively, and the atomic weights of P, Sr, Ba, and Zn are set as M(P), M(Sr), and M(Ba), respectively, and N1 is set as N1 = [{C(Ba) / M(Ba)} + {C(Sr) / M(Sr)}] / {C(P) / M(P)}, from the viewpoint of increasing the refractive index nd, the lower limit of N1 is preferably 1.05, and more preferably in the order of 1.15, 1.25, 1.35, and 1.45. Furthermore, from the viewpoint of improving stability during reheating, the upper limit of N1 is preferably 2.25, and more preferably in the order of 2.15, 2.05, 1.95, and 1.85.

[0443] In the optical glass of the second embodiment, from the viewpoint of improving the refractive index nd, the lower limit of the molar ratio of the total content of Ba, Sr, and Zn to the content of P [(Ba+Sr+Zn) / P] is preferably 1.1, and more preferably in the order of 1.2, 1.3, 1.4, and 1.5. Furthermore, from the viewpoint of improving stability during reheating, the upper limit of the molar ratio [(Ba+Sr+Zn) / P] is preferably 2.3, and more preferably in the order of 2.2, 2.1, 2.0, and 1.9.

[0444] Furthermore, in the optical glass of the second embodiment, when the contents of P, Sr, Ba, and Zn, expressed as mass percent, are set as C(P), C(Sr), C(Ba), and C(Zn), respectively, and the atomic weights of P, Sr, Ba, and Zn are set as M(P), M(Sr), M(Ba), and M(Zn), respectively, and I1 is set as I1 = [{C(Ba) / M(Ba)} + {C(Sr) / M(Sr)} + ​​{C(Zn) / M(Zn)}] / {C(P) / M(P)}, from the viewpoint of improving the refractive index, the lower limit of I1 is preferably 1.1, and more preferably in the order of 1.2, 1.3, 1.4, and 1.5. From the viewpoint of improving stability during reheating, the upper limit of I1 is preferably 2.3, and more preferably in the order of 2.2, 2.1, 2.0, and 1.9.

[0445] In the optical glass of the second embodiment, from the viewpoint of suppressing the volatilization of glass components, the lower limit of the O content is preferably 12 mol%, and more preferably in the order of 13 mol% and 14 mol%. From the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the upper limit of the O content is preferably 26 mol%, and more preferably in the order of 25 mol% and 24 mol%.

[0446] Furthermore, in the optical glass of the second embodiment, from the viewpoint of suppressing the volatilization of glass components, the lower limit of the O content is preferably 6.40% by mass, and more preferably in the order of 6.93% by mass and 7.47% by mass. From the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the upper limit of the O content is preferably 12.61% by mass, and more preferably in the order of 12.12% by mass and 11.64% by mass.

[0447] In the optical glass of the second embodiment, from the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the lower limit of the F content is preferably 30 mol%, and more preferably in the order of 31 mol% and 32 mol%. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the F content is preferably 54 mol%, and more preferably in the order of 53 mol% and 52 mol%.

[0448] Furthermore, in the optical glass of the second embodiment, from the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the lower limit of the F content is preferably 17.27% by mass, and more preferably in the order of 17.85% by mass and 18.42% by mass. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the F content is preferably 40.00% by mass, and more preferably in the order of 39.00% by mass, 38.00% by mass, 37.00% by mass, 36.00% by mass, 35.00% by mass, 34.20% by mass, 33.56% by mass and 32.93% by mass.

[0449] In the optical glass of the second embodiment, from the viewpoint of promoting clarification, the lower limit of the Cl content is preferably 0.00 mol%, and more preferably in the order of 0.02 mol% and 0.04 mol%. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the Cl content is preferably 0.20 mol%, and more preferably in the order of 0.15 mol% and 0.10 mol%.

[0450] Furthermore, in the optical glass of the second embodiment, from the viewpoint of promoting clarification, the lower limit of the Cl content is preferably 0% by mass, and more preferably in the order of 0.02% by mass and 0.05% by mass. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the Cl content is preferably 0.21% by mass, and more preferably in the order of 0.16% by mass and 0.11% by mass.

[0451] In the optical glass of the second embodiment, from the viewpoint of improving resistance to devitrification during melting and improving stability during reheating, the lower limit of the P content is preferably 1.0 mol%, and more preferably in the order of 2.0 mol%, 3.0 mol%, and 3.2 mol%. Furthermore, from the viewpoint of improving the refractive index nd, the upper limit of the P content is preferably 9.0 mol%, and more preferably in the order of 8.0 mol%, 7.0 mol%, and 6.5 mol%.

[0452] Furthermore, in the optical glass of the second embodiment, from the viewpoint of improving resistance to devitrification during melting and improving stability during reheating, the lower limit of the P content is preferably 1.03% by mass, and more preferably in the order of 2.06% by mass, 3.10% by mass, and 3.30% by mass. Furthermore, from the viewpoint of improving the refractive index nd, the upper limit of the P content is preferably 8.45% by mass, and more preferably in the order of 7.51% by mass, 6.57% by mass, and 6.10% by mass.

[0453] In the optical glass of the second embodiment, from the viewpoint of high refractive index and low dispersion, the lower limit of the Al content is preferably 7.0 mol%, and more preferably in the order of 7.5 mol%, 8.0 mol%, and 8.5 mol%. Furthermore, from the viewpoint of improving resistance to devitrification during melting and improving stability during reheating, the upper limit of the Al content is preferably 12 mol%, and more preferably in the order of 11.0 mol%, 10.5 mol%, and 10.0 mol%.

[0454] Furthermore, in the optical glass of the second embodiment, from the viewpoint of high refractive index and low dispersion, the lower limit of the Al content is preferably 6.30% by mass, and more preferably in the order of 6.75% by mass, 7.20% by mass, and 7.64% by mass. Additionally, from the viewpoint of improving resistance to devitrification during melting and improving stability during reheating, the upper limit of the Al content is preferably 9.81% by mass, and more preferably in the order of 8.99% by mass, 8.59% by mass, and 8.18% by mass.

[0455] In the optical glass of the second embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the content of B is preferably 1.0 mol%, and more preferably in the order of 0.5 mol%, 0.2 mol%, and 0.1 mol%. Furthermore, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the content of B is preferably 0 mol%. The content of B can be 0 mol%.

[0456] Furthermore, in the optical glass of the second embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the B content is preferably 0.36% by mass, and more preferably in the order of 0.18% by mass, 0.07% by mass, and 0.04% by mass. Additionally, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the B content is preferably 0% by mass. The B content can be 0% by mass.

[0457] In the optical glass of the second embodiment, from the viewpoint of maintaining meltability and thermal stability and suppressing the volatilization of glass components, the upper limit of the Si content is preferably 1.0 mol%, and more preferably in the order of 0.5 mol%, 0.2 mol%, and 0.1 mol%. Furthermore, the lower limit of the Si content is preferably 0 mol%. The Si content can be 0 mol%.

[0458] Furthermore, in the optical glass of the second embodiment, from the viewpoint of maintaining meltability and thermal stability and suppressing the volatilization of glass components, the upper limit of the Si content is preferably 0.94% by mass, and more preferably in the order of 0.47% by mass, 0.19% by mass, and 0.09% by mass. Additionally, the lower limit of the Si content is preferably 0% by mass. The Si content can be 0% by mass.

[0459] In the glass of the second embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Li content is preferably 6.5 mol%, and more preferably in the order of 6.0 mol%, 5.5 mol%, and 5.0 mol%. Furthermore, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the Li content is preferably 0 mol%.

[0460] Furthermore, in the glass of the second embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Li content is preferably 1.37% by mass, and more preferably in the order of 1.26% by mass, 1.16% by mass, and 1.05% by mass. Additionally, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the Li content is preferably 0% by mass.

[0461] In the glass of the second embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Na content is preferably 2.0 mol%, and more preferably in the order of 1.5 mol%, 1.0 mol%, and 0.5 mol%. Furthermore, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the Na content is preferably 0 mol%. The Na content can be 0 mol%.

[0462] Furthermore, in the glass of the second embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Na content is preferably 1.39% by mass, and more preferably in the order of 1.04% by mass, 0.70% by mass, and 0.35% by mass. Additionally, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the Na content is preferably 0% by mass. The Na content can be 0% by mass.

[0463] In the optical glass of the second embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the K content is preferably 2.0 mol%, and more preferably in the order of 1.5 mol%, 1.0 mol%, and 0.5 mol%. From the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the K content is preferably 0 mol%. The K content can be 0 mol%.

[0464] Furthermore, in the optical glass of the second embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the K content is preferably 2.37% by mass, and more preferably in the order of 1.78% by mass, 1.18% by mass, and 0.59% by mass. From the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the K content is preferably 0% by mass. The K content can be 0% by mass.

[0465] Furthermore, in the optical glass of the second embodiment, from the viewpoint of improving stability during reheating and improving mechanical strength and thermal shock resistance, the lower limit of the Mg content is preferably 0.3 mol%, and more preferably in the order of 0.6 mol%, 0.8 mol%, and 1.0 mol%. From the viewpoint of improving resistance to devitrification during melting, the upper limit of the Mg content is preferably 5.0 mol%, and more preferably in the order of 4.0 mol%, 3.5 mol%, and 3.0 mol%.

[0466] Furthermore, in the optical glass of the second embodiment, from the viewpoint of improving stability during reheating and improving mechanical strength and thermal shock resistance, the lower limit of the Mg content is preferably 0.24% by mass, and more preferably in the order of 0.49% by mass, 0.65% by mass, and 0.81% by mass. From the viewpoint of improving resistance to devitrification during melting, the upper limit of the Mg content is preferably 3.68% by mass, and more preferably in the order of 2.95% by mass, 2.58% by mass, and 2.21% by mass.

[0467] In the optical glass of the second embodiment, from the viewpoint of improving stability during reheating and improving mechanical strength and thermal shock resistance, the lower limit of the Ca content is preferably 2.0 mol%, and more preferably in the order of 2.5 mol%, 3.0 mol%, and 3.5 mol%. Furthermore, from the viewpoint of improving resistance to devitrification during melting, the upper limit of the Ca content is preferably 9.0 mol%, and more preferably in the order of 8.5 mol%, 8.0 mol%, and 7.8 mol%.

[0468] Furthermore, in the optical glass of the second embodiment, from the viewpoint of improving stability during reheating and improving mechanical strength and thermal shock resistance, the lower limit of the Ca content is preferably 2.67% by mass, and more preferably in the order of 3.34% by mass, 4.01% by mass, and 4.68% by mass. Furthermore, from the viewpoint of improving resistance to devitrification during melting, the upper limit of the Ca content is preferably 10.93% by mass, and more preferably in the order of 10.32% by mass, 9.72% by mass, and 9.47% by mass.

[0469] In the optical glass of the second embodiment, from the viewpoint of improving stability during reheating, the upper limit of the Sr content is preferably 7.2 mol%, and more preferably in the order of 7.0 mol%, 6.8 mol%, and 6.6 mol%. Furthermore, from the viewpoint of improving the refractive index nd, the lower limit of the Sr content is preferably 1.0 mol%, and more preferably in the order of 1.2 mol%, 1.4 mol%, and 1.6 mol%.

[0470] Furthermore, in the optical glass of the second embodiment, from the viewpoint of improving stability during reheating, the upper limit of the Sr content is preferably 19.12% by mass, and more preferably in the order of 18.59% by mass, 18.06% by mass, and 17.52% by mass. Furthermore, from the viewpoint of improving the refractive index nd, the lower limit of the Sr content is preferably 2.92% by mass, and more preferably in the order of 3.50% by mass, 4.09% by mass, and 4.67% by mass.

[0471] In the optical glass of the second embodiment, from the viewpoint of improving stability upon reheating, the upper limit of the Ba content is preferably 7.2 mol%, and more preferably in the order of 7.0 mol%, 6.8 mol%, and 6.6 mol%. From the viewpoint of improving the refractive index nd, the lower limit of the Ba content is preferably 1.0 mol%, and more preferably in the order of 1.2 mol%, 1.4 mol%, and 1.6 mol%.

[0472] Furthermore, in the optical glass of the second embodiment, from the viewpoint of improving stability during reheating, the upper limit of the Ba content is preferably 29.96% by mass, and more preferably in the order of 29.13% by mass, 28.3% by mass, and 27.47% by mass. From the viewpoint of improving the refractive index nd, the lower limit of the Ba content is preferably 4.58% by mass, and more preferably in the order of 5.49% by mass, 6.41% by mass, and 7.32% by mass.

[0473] In the optical glass of the second embodiment, from the viewpoint of suppressing high dispersion, the upper limit of the Zn content is preferably 1.0 mol%, and more preferably in the order of 0.8 mol%, 0.5 mol%, and 0.2 mol%. Furthermore, the lower limit of the Zn content is preferably 0 mol%. The Zn content can be 0 mol%.

[0474] Furthermore, in the optical glass of the second embodiment, from the viewpoint of suppressing high dispersion, the upper limit of the Zn content is preferably 2.18% by mass, and more preferably in the order of 1.98% by mass, 1.59% by mass, 0.99% by mass, and 0.40% by mass. Additionally, the lower limit of the Zn content is preferably 0% by mass. The Zn content can be 0% by mass.

[0475] In the optical glass of the second embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the La content is preferably 1.0 mol%, and more preferably in the order of 0.9 mol% and 0.8 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the La content is preferably 0 mol%. The La content can be 0 mol%.

[0476] Furthermore, in the optical glass of the second embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability during reheating, the upper limit of the La content is preferably 4.21% by mass, and more preferably in the order of 3.79% by mass and 3.37% by mass. Additionally, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the La content is preferably 0% by mass. The La content can be 0% by mass.

[0477] In the glass of the second embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the Gd content is preferably 1.0 mol%, and more preferably in the order of 0.9 mol% and 0.8 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the Gd content is preferably 0 mol%. The Gd content can be 0 mol%.

[0478] Furthermore, in the glass of the second embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability during reheating, the upper limit of the Gd content is preferably 4.77% by mass, and more preferably in the order of 4.29% by mass and 3.81% by mass. Additionally, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the Gd content is preferably 0% by mass. The Gd content can be 0% by mass.

[0479] In the glass of the second embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the Y content is preferably 1.0 mol%, and more preferably in the order of 0.9 mol% and 0.8 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the Y content is preferably 0 mol%.

[0480] Furthermore, in the glass of the second embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the Y content is preferably 2.69% by mass, and more preferably in the order of 2.42% by mass and 2.16% by mass. Additionally, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the Y content is preferably 0% by mass.

[0481] In the glass of the second embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the Lu content is preferably 1.0 mol%, and more preferably in the order of 0.9 mol% and 0.8 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the Lu content is preferably 0 mol%. The Lu content can be 0 mol%.

[0482] Furthermore, in the glass of the second embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the Lu content is preferably 5.30% by mass, more preferably in the order of 4.77% by mass and 4.24% by mass. Additionally, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the Lu content is preferably 0% by mass. The Lu content can be 0% by mass.

[0483] In the glass of the second embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the Yb content is preferably 1.0 mol%, and more preferably in the order of 0.9 mol% and 0.8 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the Yb content is preferably 0 mol%. The Yb content can be 0 mol%.

[0484] Furthermore, in the glass of the second embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the Yb content is preferably 5.24% by mass, and more preferably in the order of 4.72% by mass and 4.19% by mass. Additionally, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the Yb content is preferably 0% by mass. The Yb content can be 0% by mass.

[0485] In the optical glass of the second embodiment, from the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the upper limit of the Zr content is preferably 1.0 mol%, and more preferably in the order of 0.5 mol%, 0.2 mol%, and 0.1 mol%. The lower limit of the Zr content is preferably 0 mol%. The Zr content can be 0 mol%.

[0486] Furthermore, in the optical glass of the second embodiment, from the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the upper limit of the Zr content is preferably 3.04% by mass, and more preferably in the order of 1.52% by mass, 0.61% by mass, and 0.30% by mass. The lower limit of the Zr content is preferably 0% by mass. The Zr content can be 0% by mass.

[0487] In the optical glass of the second embodiment, the content and ratio of glass components other than those described above can be the same as in this embodiment described above.

[0488] In the optical glass of the second embodiment, the glass properties can be the same as those of the present embodiment described above.

[0489] The manufacturing of optical glass, optical element blanks, and optical elements in the second embodiment can also be the same as in the present embodiment described above.

[0490] Third implementation method

[0491] The third embodiment is one of the preferred embodiments of the present embodiment described above.

[0492] In the third embodiment, in particular, by controlling the ratio of F content to Al content to a high level, an optical glass is made that improves low dispersion, ensures anomalous partial dispersion, prioritizes stability during reheating over suppressing the volatilization of glass components, and can further improve stability during reheating.

[0493] As a preferred embodiment of the third embodiment, embodiments 3-1 and 3-2 are shown.

[0494] Implementation Method 3-1

[0495] Preferably, in the optical glass of the third-1 embodiment,

[0496] The molar ratio of F to Al [F / Al] is 4.60–15.0.

[0497] The molar ratio of Ba to P [Ba / P] is 0.400–0.820.

[0498] The molar ratio of P to Al [P / Al] is 0.20–1.25.

[0499] The molar ratio of O to P [O / P] is 3.05–3.49.

[0500] The molar ratio of F content to the total content of O, F, and Cl [F / (O+F+Cl)] is 0.010–0.790.

[0501] The molar ratio of the total content of Sr and Ba to the total content of Mg, Ca, Sr, Ba and Zn [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] is 0.00 to 0.67.

[0502] Furthermore, the optical glass of the third-1 embodiment is preferred.

[0503] The contents of F, Al, Ba, P, O, Cl, Mg, Ca, Sr, Ba, and Zn, expressed as mass percent, are respectively set as C(F), C(Al), C(Ba), C(P), C(O), C(Cl), C(Mg), C(Ca), C(Sr), C(Ba), and C(Zn).

[0504] Let the atomic weights of F, Al, Ba, P, O, Cl, Mg, Ca, Sr, Ba, and Zn be M(F), M(Al), M(Ba), M(P), M(O), M(Cl), M(Mg), M(Ca), M(Sr), M(Ba), and M(Zn), respectively.

[0505] And set it as:

[0506] A1={C(F) / M(F)} / {C(Al) / M(Al)}

[0507] B1={C(Ba) / M(Ba)} / {C(P) / M(P)}

[0508] C1={C(P) / M(P)} / {C(Al) / M(Al)}

[0509] D1 = {C(O) / M(O)} / {C(P) / M(P)}

[0510] G1=[{C(F) / M(F)} / [{C(O) / M(O)}+{C(F) / M(F)}+{C(Cl) / M(Cl)}]]

[0511] When H1=[{C(Sr) / M(Sr)}+{C(Ba) / M(Ba)}] / [{C(Mg) / M(Mg)}+{C(Ca) / M(Ca)}+{C(Sr) / M(Sr)}+{C(Ba) / M(Ba)}+{C(Zn) / M(Zn)}],

[0512] A1 ranges from 4.60 to 15.0.

[0513] B1 ranges from 0.400 to 0.820.

[0514] C1 ranges from 0.20 to 1.25.

[0515] D1 ranges from 3.05 to 3.49.

[0516] G1 ranges from 0.010 to 0.790.

[0517] H1 ranges from 0.00 to 0.67.

[0518] Implementation Method 3-2

[0519] Preferably, in the optical glass of the third-2nd embodiment,

[0520] The molar ratio of F to Al [F / Al] is 4.60–15.0.

[0521] The molar ratio of Ba to P [Ba / P] is 0.400–0.820.

[0522] The molar ratio of P to Al [P / Al] is 0.20–1.25.

[0523] The molar ratio of O to P [O / P] is 3.05–3.49.

[0524] The molar ratio of F content to the total content of O, F and Cl [F / (O+F+Cl)] is 0.010 to 0.790, and the total content of Li, Na and K [Li+Na+K] is 0.00 to 6.40 mol%.

[0525] Furthermore, in the optical glass of the third-2nd embodiment,

[0526] The contents of F, Al, Ba, P, O, Cl, Li, Na, and K, expressed as mass percent, are respectively set as C(F), C(Al), C(Ba), C(P), C(O), C(Cl), C(Li), C(Na), and C(K).

[0527] Let the atomic weights of F, Al, Ba, P, O, Cl, Li, Na, and K be M(F), M(Al), M(Ba), M(P), M(O), M(Cl), M(Li), M(Na), and M(K), respectively.

[0528] And set it as:

[0529] A1={C(F) / M(F)} / {C(Al) / M(Al)}

[0530] B1={C(Ba) / M(Ba)} / {C(P) / M(P)}

[0531] C1={C(P) / M(P)} / {C(Al) / M(Al)}

[0532] D1 = {C(O) / M(O)} / {C(P) / M(P)}

[0533] G1=[{C(F) / M(F)} / [{C(O) / M(O)}+{C(F) / M(F)}+{C(Cl) / M(Cl)}]]

[0534] When F1=[{C(Li) / M(Li)}+{C(Na) / M(Na)}+{C(K) / M(K)}]×100,

[0535] A1 ranges from 4.60 to 15.0.

[0536] B1 ranges from 0.400 to 0.820.

[0537] C1 ranges from 0.20 to 1.25.

[0538] D1 ranges from 3.05 to 3.49.

[0539] G1 ranges from 0.010 to 0.790.

[0540] F1 ranges from 0.0 to 6.4.

[0541] The content and ratio of glass components in the optical glass of the third embodiment (the third-1st embodiment and the third-2nd embodiment) will be described in detail below.

[0542] In the optical glass of the third embodiment, from the viewpoint of improving stability during reheating, the lower limit of the molar ratio of F content to Al content [F / Al] is preferably 4.60, and more preferably in the order of 4.70, 4.80, 4.90, 5.00, 5.10, and 5.20. Furthermore, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the molar ratio [F / Al] is preferably 15.0, and more preferably in the order of 10.0, 8.0, 7.5, 7.0, 6.8, and 6.5.

[0543] Furthermore, in the optical glass of the third embodiment, when the contents of F and Al expressed as mass percent are set as C(F) and C(Al), respectively, and the atomic weights of F and Al are set as M(F) and M(Al), respectively, and A1 is set as A1 = {C(F) / M(F)} / {C(Al) / M(Al)}, from the viewpoint of improving stability during reheating, the lower limit of A1 is preferably 4.60, and more preferably in the order of 4.70, 4.80, 4.90, 5.00, 5.10, and 5.20. Furthermore, from the viewpoint of suppressing the volatilization of glass components, the upper limit of A1 is preferably 15.0, and more preferably in the order of 10.0, 8.0, 7.5, 7.0, 6.8, and 6.5.

[0544] In the optical glass of the third embodiment, from the viewpoint of improving the refractive index nd, the lower limit of the molar ratio of Ba content to P content [Ba / P] is preferably 0.400, and more preferably in the order of 0.410, 0.420, and 0.430. Furthermore, from the viewpoint of improving stability during reheating, the upper limit of the molar ratio [Ba / P] is preferably 0.820, and more preferably in the order of 0.700, 0.650, and 0.600.

[0545] Furthermore, in the optical glass of the third embodiment, when the contents of Ba and P, expressed as mass percent, are set as C(Ba) and C(P), respectively, and the atomic weights of Ba and P are set as M(Ba) and M(P), respectively, and B1 is set as B1 = {C(Ba) / M(Ba)} / {C(P) / M(P)}, from the viewpoint of increasing the refractive index nd, the lower limit of B1 is preferably 0.400, and more preferably in the order of 0.410, 0.420, and 0.430. Furthermore, from the viewpoint of improving stability during reheating, the upper limit of B1 is preferably 0.820, and more preferably in the order of 0.700, 0.650, and 0.600.

[0546] In the optical glass of the third embodiment, from the viewpoint of high refractive index and low dispersion, the upper limit of the molar ratio of P content to Al content [P / Al] is preferably 1.25, and more preferably in the order of 1.20, 1.15, 1.10, 1.00, 0.950, 0.900, and 0.850. Furthermore, from the viewpoint of improving resistance to devitrification during melting and stability during reheating, the lower limit of the molar ratio [P / Al] is preferably 0.20, and more preferably in the order of 0.400, 0.450, 0.500, and 0.550.

[0547] Furthermore, in the optical glass of the third embodiment, when the contents of Al and P, expressed as mass percent, are set as C(Al) and C(P), respectively, and the atomic weights of Al and P are set as M(Al) and M(P), respectively, and C1 is set as C1 = {C(P) / M(P)} / {C(Al) / M(Al)}, from the viewpoint of high refractive index and low dispersion, the upper limit of C1 is preferably 1.25, and more preferably in the order of 1.20, 1.15, 1.10, 1.00, 0.950, 0.900, and 0.850. Furthermore, from the viewpoint of improving resistance to devitrification during melting and stability during reheating, the lower limit of C1 is preferably 0.20, and more preferably in the order of 0.400, 0.450, 0.500, and 0.550.

[0548] In the optical glass of the third embodiment, from the viewpoint of suppressing the volatilization of glass components, the lower limit of the molar ratio of O to P [O / P] is preferably 3.05, and more preferably in the order of 3.06, 3.07, 3.08, 3.09, 3.10, 3.15, 3.25, and 3.30. Furthermore, from the viewpoint of improving stability during molding and reheating, the upper limit of the molar ratio [O / P] is preferably 3.49, and more preferably in the order of 3.45, 3.42, and 3.40.

[0549] Furthermore, in the optical glass of the third embodiment, when the contents of P and O, expressed as mass percent, are set as C(P) and C(O), respectively, and the atomic weights of P and O are set as M(P) and M(O), respectively, and D1 is set as D1 = {C(O) / M(O)} / {C(P) / M(P)}, from the viewpoint of suppressing the volatilization of glass components, the lower limit of D1 is preferably 3.05, and more preferably in the order of 3.06, 3.07, 3.08, 3.09, 3.10, 3.15, 3.25, and 3.30. Furthermore, from the viewpoint of improving stability during molding and reheating, the upper limit of D1 is preferably 3.49, and more preferably in the order of 3.45, 3.42, and 3.40.

[0550] In the optical glass of the third embodiment, from the viewpoint of improving low dispersion and anomalous partial dispersion, the lower limit of the molar ratio of F content to the total content of O, F and Cl [F / (O+F+Cl)] is preferably 0.010, and more preferably in the order of 0.400, 0.420, 0.450, 0.500, 0.550, 0.600, 0.625, and 0.650. From the viewpoint of improving the stability of the glass and suppressing volatilization, the upper limit of the molar ratio [F / (O+F+Cl)] is preferably 0.940, and more preferably in the order of 0.890, 0.850, 0.820, 0.810, 0.800, 0.790, 0.780, 0.770, 0.760, and 0.750.

[0551] Furthermore, in the optical glass of the third embodiment, when the contents of F, O, and Cl expressed in mass percent are set as C(F), C(O), and C(Cl), respectively, and the atomic weights of F, O, and Cl are set as M(F), M(O), and M(Cl), respectively, and G1 is set as G1 = [{C(F) / M(F)} / [{C(O) / M(O)}+{C(F) / M(F)}+{C(Cl) / M(Cl)}]], from the viewpoint of improving low dispersion and anomalous partial dispersion, the lower limit of G1 is preferably 0.010, and more preferably in the order of 0.400, 0.420, 0.450, 0.50, 0.550, 0.600, 0.625, and 0.650. From the viewpoint of improving stability during reheating and suppressing volatilization, the upper limit of G1 is preferably 0.940, and even more preferably in the order of 0.890, 0.850, 0.820, 0.810, 0.800, 0.790, 0.780, 0.770, 0.760, and 0.750.

[0552] In the optical glass of the third embodiment, from the viewpoint of improving the refractive index nd, the lower limit of the molar ratio of the total content of Sr and Ba to the total content of Mg, Ca, Sr, Ba and Zn [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] is preferably 0.00, and more preferably in the order of 0.300, 0.350, 0.400, 0.450, and 0.480. From the viewpoint of improving stability during reheating, the upper limit of the molar ratio [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] is preferably 0.67, and more preferably in the order of 0.667, 0.650, 0.640, 0.630, and 0.620.

[0553] Furthermore, in the optical glass of the third embodiment, the contents of Mg, Ca, Sr, Ba, and Zn, expressed as mass percent, are set as C(Mg), C(Ca), C(Sr), C(Ba), and C(Zn), respectively; the atomic weights of Mg, Ca, Sr, Ba, and Zn are set as M(Mg), M(Ca), M(Sr), M(Ba), and M(Zn), respectively; and H1 is set as H1 = [{C(Sr) / M(Sr)} + ​​{C When H1 is [{C(Mg) / M(Mg)}+{C(Ca) / M(Ca)}+{C(Sr) / M(Sr)}+{C(Ba) / M(Ba)}+{C(Zn) / M(Zn)}], from the viewpoint of increasing the refractive index nd, the lower limit of H1 is preferably 0.00, and more preferably in the order of 0.300, 0.350, 0.400, 0.450, and 0.480. From the viewpoint of improving stability during reheating, the upper limit of H1 is preferably 0.67, and more preferably in the order of 0.667, 0.650, 0.640, 0.630, and 0.620.

[0554] In the optical glass of the third embodiment, from the viewpoint of improving the meltability of the glass raw materials, the lower limit of the total content of Li, Na, and K [Li+Na+K] is preferably 0.00 mol%, and more preferably in the order of 0.20 mol%, 0.40 mol%, and 0.60 mol%. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the total content [Li+Na+K] is preferably 6.50 mol%, and more preferably in the order of 6.40 mol%, 6.00 mol%, 5.50 mol%, and 5.00 mol%.

[0555] Furthermore, in the optical glass of the third embodiment, when the contents of Li, Na, and K, expressed as mass percent, are set as C(Li), C(Na), and C(K), respectively, and the atomic weights of Li, Na, and K are set as M(Li), M(Na), and M(K), respectively, and F1 is set as F1 = [{C(Li) / M(Li)} + {C(Na) / M(Na)} + {C(K) / M(K)}] × 100, from the viewpoint of improving the meltability of the glass raw material, the lower limit of F1 is preferably 0, and more preferably in the order of 0.6, 1.2, and 1.8. From the viewpoint of suppressing the volatilization of glass components, the upper limit of F1 is preferably 19.5, and more preferably in the order of 18.0, 16.5, and 15.0.

[0556] In the optical glass of the third embodiment, from the viewpoint of improving the refractive index nd and improving chemical durability, the lower limit of the total content of Y, La, Gd, Yb and Lu [Y+La+Gd+Yb+Lu] is preferably 0.0 mol%, and more preferably in the order of 0.05 mol%, 0.10 mol%, and 0.15 mol%. From the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the upper limit of the total content [Y+La+Gd+Yb+Lu] is preferably 2.0 mol%, and more preferably in the order of 1.5 mol%, 1.4 mol%, 1.2 mol%, and 1.0 mol%.

[0557] Furthermore, in the optical glass of the third embodiment, the contents of Y, La, Gd, Yb, and Lu, expressed as mass percent, are set as C(Y), C(La), C(Gd), C(Yb), and C(Lu), respectively, and the atomic weights of Y, La, Gd, Yb, and Lu are set as M(Y), M(La), M(Gd), M(Yb), and M(Lu), respectively. When K1 is set as K1 = [{C(Y) / M(Y)} + {C(La) / M(La)} + {C(Gd) / M(Gd)} + {C(Yb) / M(Yb)} + {C(Lu) / M(Lu)}] × 100, from the viewpoint of increasing the refractive index nd and improving chemical durability, the lower limit of K1 is preferably 0, and more preferably in the order of 0.15, 0.30, and 0.45. From the viewpoint of improving the meltability of glass raw materials and improving the resistance to devitrification during melting, the upper limit of K1 is preferably 6.0, and even more preferably in the order of 4.5, 3.6 and 3.0.

[0558] In the optical glass of the third embodiment, from the viewpoint of improving stability during reheating, the lower limit of the molar ratio of the total content of Ba and Sr to the content of P [(Ba+Sr) / P] is preferably 0.72, and more preferably in the order of 0.82, 0.92, 1.02, 1.07, and 1.12. Furthermore, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the molar ratio [(Ba+Sr) / P] is preferably 1.70, and more preferably in the order of 1.63, 1.58, 1.53, and 1.48.

[0559] Furthermore, in the optical glass of the third embodiment, when the contents of P, Sr, and Ba, expressed as mass percent, are set as C(P), C(Sr), and C(Ba), respectively, and the atomic weights of P, Sr, Ba, and Zn are set as M(P), M(Sr), and M(Ba), respectively, and N1 = [{C(Ba) / M(Ba)} + {C(Sr) / M(Sr)}] / {C(P) / M(P)}, from the viewpoint of improving stability during reheating, the lower limit of N1 is preferably 0.72, and more preferably in the order of 0.82, 0.92, 1.02, 1.07, and 1.12. Furthermore, from the viewpoint of suppressing the volatilization of glass components, the upper limit of N1 is preferably 1.70, and more preferably in the order of 1.63, 1.58, 1.53, and 1.48.

[0560] In the optical glass of the third embodiment, from the viewpoint of improving the refractive index nd, the lower limit of the molar ratio of the total content of Ba, Sr, and Zn to the content of P [(Ba+Sr+Zn) / P] is preferably 0.40, and more preferably in the order of 0.50, 0.60, 0.67, 0.77, 0.87, 0.97, and 1.07. Furthermore, from the viewpoint of improving stability during reheating, the upper limit of the molar ratio [(Ba+Sr+Zn) / P] is preferably 1.70, and more preferably in the order of 1.65, 1.60, 1.55, and 1.50.

[0561] Furthermore, in the optical glass of the third embodiment, when the contents of P, Sr, Ba, and Zn, expressed as mass percent, are set as C(P), C(Sr), C(Ba), and C(Zn), respectively, and the atomic weights of P, Sr, Ba, and Zn are set as M(P), M(Sr), M(Ba), and M(Zn), respectively, and when I1 is set as I1 = [{C(Ba) / M(Ba)} + {C(Sr) / M(Sr)} + ​​{C(Zn) / M(Zn)}] / {C(P) / M(P)}, from the viewpoint of improving the refractive index nd, the lower limit of I1 is preferably 0.40, and more preferably in the order of 0.50, 0.60, 0.67, 0.77, 0.87, 0.97, and 1.07. From the viewpoint of improving stability during reheating, the upper limit of I1 is preferably 1.70, and more preferably in the order of 1.65, 1.60, 1.55, and 1.50.

[0562] In the optical glass of the third embodiment, from the viewpoint of suppressing the volatilization of glass components, the lower limit of the O content is preferably 12 mol%, and more preferably in the order of 13 mol% and 14 mol%. From the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the upper limit of the O content is preferably 26 mol%, and more preferably in the order of 25 mol% and 24 mol%.

[0563] Furthermore, in the optical glass of the third embodiment, from the viewpoint of suppressing the volatilization of glass components, the lower limit of the O content is preferably 6.40% by mass, and more preferably in the order of 6.93% by mass and 7.47% by mass. From the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the upper limit of the O content is preferably 18% by mass, and more preferably in the order of 16% by mass, 14% by mass, 13.5% by mass, 12.61% by mass, 12.12% by mass and 11.64% by mass.

[0564] In the optical glass of the third embodiment, from the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the lower limit of the F content is preferably 30 mol%, and more preferably in the order of 31 mol% and 32 mol%. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the F content is preferably 54 mol%, and more preferably in the order of 53 mol% and 52 mol%.

[0565] Furthermore, in the optical glass of the third embodiment, from the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the lower limit of the F content is preferably 17.27% by mass, and more preferably in the order of 17.85% by mass and 18.42% by mass. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the F content is preferably 38.00% by mass, and more preferably in the order of 36% by mass, 34.20% by mass, 33.56% by mass and 32.93% by mass.

[0566] In the optical glass of the third embodiment, from the viewpoint of promoting clarification, the lower limit of the Cl content is preferably 0.00 mol%, and more preferably in the order of 0.02 mol% and 0.04 mol%. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the Cl content is preferably 0.20 mol%, and more preferably in the order of 0.15 mol% and 0.10 mol%.

[0567] Furthermore, in the optical glass of the third embodiment, from the viewpoint of promoting clarification, the lower limit of the Cl content is preferably 0% by mass, and more preferably in the order of 0.02% by mass and 0.05% by mass. From the viewpoint of suppressing the volatilization of glass components, the upper limit of the Cl content is preferably 0.21% by mass, and more preferably in the order of 0.16% by mass and 0.11% by mass.

[0568] In the optical glass of the third embodiment, from the viewpoint of improving resistance to devitrification during melting and improving stability during reheating, the lower limit of the P content is preferably 2.0 mol%, and more preferably in the order of 3.0 mol%, 4.0 mol%, and 4.5 mol%. Furthermore, from the viewpoint of improving the refractive index nd, the upper limit of the P content is preferably 15 mol%, and more preferably in the order of 12 mol%, 10 mol%, and 9 mol%.

[0569] Furthermore, in the optical glass of the third embodiment, from the viewpoint of improving resistance to devitrification during melting and improving stability during reheating, the lower limit of the P content is preferably 2.06% by mass, and more preferably in the order of 3.10% by mass, 4.13% by mass, and 4.65% by mass. Furthermore, from the viewpoint of improving the refractive index nd, the upper limit of the P content is preferably 14.08% by mass, and more preferably in the order of 11.26% by mass, 9.39% by mass, and 8.45% by mass.

[0570] In the optical glass of the third embodiment, from the viewpoint of high refractive index and low dispersion, the lower limit of the Al content is preferably 3.0 mol%, and more preferably in the order of 4.0 mol%, 5.0 mol%, and 6.0 mol%. Furthermore, from the viewpoint of improving resistance to devitrification during melting and improving stability during reheating, the upper limit of the Al content is preferably 12 mol%, and more preferably in the order of 11.0 mol%, 10.5 mol%, and 10.0 mol%.

[0571] Furthermore, in the optical glass of the third embodiment, from the viewpoint of high refractive index and low dispersion, the lower limit of the Al content is preferably 2.7% by mass, and more preferably in the order of 3.6% by mass, 4.5% by mass, and 5.4% by mass. Additionally, from the viewpoint of improving resistance to devitrification during melting and improving stability during reheating, the upper limit of the Al content is preferably 9.81% by mass, and more preferably in the order of 8.99% by mass, 8.59% by mass, and 8.18% by mass.

[0572] In the optical glass of the third embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the content of B is preferably 1.0 mol%, and more preferably in the order of 0.5 mol%, 0.2 mol%, and 0.1 mol%. Furthermore, the lower limit of the content of B is preferably 0 mol%. The content of B can be 0 mol%.

[0573] Furthermore, in the optical glass of the third embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the B content is preferably 0.36% by mass, and more preferably in the order of 0.18% by mass, 0.07% by mass, and 0.04% by mass. Additionally, the lower limit of the B content is preferably 0% by mass. The B content can be 0% by mass.

[0574] In the optical glass of the third embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Si content is preferably 1.0 mol%, and more preferably in the order of 0.5 mol%, 0.2 mol%, and 0.1 mol%. Furthermore, the lower limit of the Si content is preferably 0 mol%. The Si content can be 0 mol%.

[0575] Furthermore, in the optical glass of the third embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Si content is preferably 0.94% by mass, and more preferably in the order of 0.47% by mass, 0.19% by mass, and 0.09% by mass. Additionally, the lower limit of the Si content is preferably 0% by mass. The Si content can be 0% by mass.

[0576] In the glass of the third embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Li content is preferably 6.5 mol%, and more preferably in the order of 6.0 mol%, 5.5 mol%, and 5.0 mol%. Furthermore, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the Li content is preferably 0 mol%.

[0577] Furthermore, in the glass of the third embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Li content is preferably 1.37% by mass, and more preferably in the order of 1.26% by mass, 1.16% by mass, and 1.05% by mass. Additionally, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the Li content is preferably 0% by mass.

[0578] In the glass of the third embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Na content is preferably 2.0 mol%, and more preferably in the order of 1.5 mol%, 1.0 mol%, and 0.5 mol%. Furthermore, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the Na content is preferably 0 mol%. The Na content can be 0 mol%.

[0579] Furthermore, in the glass of the third embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the Na content is preferably 1.39% by mass, and more preferably in the order of 1.04% by mass, 0.70% by mass, and 0.35% by mass. Additionally, from the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the Na content is preferably 0% by mass. The Na content can be 0% by mass.

[0580] In the optical glass of the third embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the K content is preferably 2.0 mol%, and more preferably in the order of 1.5 mol%, 1.0 mol%, and 0.5 mol%. From the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the K content is preferably 0 mol%. The K content can be 0 mol%.

[0581] Furthermore, in the optical glass of the third embodiment, from the viewpoint of suppressing the volatilization of glass components, the upper limit of the K content is preferably 2.37% by mass, and more preferably in the order of 1.78% by mass, 1.18% by mass, and 0.59% by mass. From the viewpoint of maintaining the meltability of the glass raw material, the lower limit of the K content is preferably 0% by mass. The K content can be 0% by mass.

[0582] In the optical glass of the third embodiment, from the viewpoint of improving stability during reheating and improving mechanical strength and thermal shock resistance, the lower limit of the Mg content is preferably 0.3 mol%, and more preferably in the order of 0.6 mol%, 0.8 mol%, and 1.0 mol%. From the viewpoint of improving resistance to devitrification during melting, the upper limit of the Mg content is preferably 5.0 mol%, and more preferably in the order of 4.0 mol%, 3.5 mol%, 3.0 mol%, and 2.5 mol%.

[0583] Furthermore, in the optical glass of the third embodiment, from the viewpoint of improving stability during reheating and improving mechanical strength and thermal shock resistance, the lower limit of the Mg content is preferably 0.24% by mass, and more preferably in the order of 0.49% by mass, 0.65% by mass, and 0.81% by mass. From the viewpoint of improving resistance to devitrification during melting, the upper limit of the Mg content is preferably 3.68% by mass, and more preferably in the order of 2.95% by mass, 2.58% by mass, and 2.21% by mass.

[0584] In the optical glass of the third embodiment, from the viewpoint of improving stability during reheating and improving mechanical strength and thermal shock resistance, the lower limit of the Ca content is preferably 2.0 mol%, and more preferably in the order of 2.5 mol%, 3.0 mol%, and 3.5 mol%. Furthermore, from the viewpoint of improving resistance to devitrification during melting, the upper limit of the Ca content is preferably 9.0 mol%, and more preferably in the order of 8.5 mol%, 8.0 mol%, 7.8 mol%, 7.5 mol%, and 7.0 mol%.

[0585] Furthermore, in the optical glass of the third embodiment, from the viewpoint of improving stability during reheating and improving mechanical strength and thermal shock resistance, the lower limit of the Ca content is preferably 2.67% by mass, and more preferably in the order of 3.34% by mass, 4.01% by mass, and 4.68% by mass. Furthermore, from the viewpoint of improving resistance to devitrification during melting, the upper limit of the Ca content is preferably 10.93% by mass, and more preferably in the order of 10.32% by mass, 9.72% by mass, and 9.47% by mass.

[0586] In the optical glass of the third embodiment, from the viewpoint of improving stability during reheating, the upper limit of the Sr content is preferably 7.2 mol%, and more preferably in the order of 7.0 mol%, 6.8 mol%, 6.6 mol%, 6.0 mol%, and 5.5 mol%. Furthermore, from the viewpoint of improving the refractive index nd, the lower limit of the Sr content is preferably 1.0 mol%, and more preferably in the order of 1.2 mol%, 1.4 mol%, and 1.6 mol%.

[0587] Furthermore, in the optical glass of the third embodiment, from the viewpoint of improving stability during reheating, the upper limit of the Sr content is preferably 19.12% by mass, and more preferably in the order of 18.59% by mass, 18.06% by mass, and 17.52% by mass. Furthermore, from the viewpoint of improving the refractive index nd, the lower limit of the Sr content is preferably 2.92% by mass, and more preferably in the order of 3.50% by mass, 4.09% by mass, and 4.67% by mass.

[0588] In the optical glass of the third embodiment, from the viewpoint of improving stability upon reheating, the upper limit of the Ba content is preferably 7.2 mol%, and more preferably in the order of 6.4 mol%, 5.8 mol%, 5.4 mol%, 5.0 mol%, 4.8 mol%, 4.4 mol%, 4.2 mol%, and 4.0 mol%. From the viewpoint of improving the refractive index nd, the lower limit of the Ba content is preferably 1.0 mol%, and more preferably in the order of 1.2 mol%, 1.4 mol%, and 1.6 mol%.

[0589] Furthermore, in the optical glass of the third embodiment, from the viewpoint of improving stability during reheating, the upper limit of the Ba content is preferably 29.96% by mass, and more preferably in the order of 26.63% by mass, 24.14% by mass, 22.47% by mass, 20.81% by mass, 19.97% by mass, 18.31% by mass, 17.48% by mass, and 16.65% by mass. From the viewpoint of improving the refractive index nd, the lower limit of the Ba content is preferably 4.58% by mass, and more preferably in the order of 5.49% by mass, 6.41% by mass, and 7.32% by mass.

[0590] In the optical glass of the third embodiment, from the viewpoint of suppressing high dispersion, the upper limit of the Zn content is preferably 1.0 mol%, and more preferably in the order of 0.8 mol%, 0.5 mol%, and 0.2 mol%. Furthermore, the lower limit of the Zn content is preferably 0 mol%. The Zn content can be 0 mol%.

[0591] Furthermore, in the optical glass of the third embodiment, from the viewpoint of suppressing high dispersion, the upper limit of the Zn content is preferably 2.18% by mass, and more preferably in the order of 1.98% by mass, 1.59% by mass, 0.99% by mass, and 0.40% by mass. Additionally, the lower limit of the Zn content is preferably 0% by mass. The Zn content can be 0% by mass.

[0592] In the optical glass of the third embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the La content is preferably 1.0 mol%, and more preferably in the order of 0.9 mol% and 0.8 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the La content is preferably 0 mol%. The La content can be 0 mol%.

[0593] Furthermore, in the optical glass of the third embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability during reheating, the upper limit of the La content is preferably 4.21% by mass, and more preferably in the order of 3.79% by mass and 3.37% by mass. Additionally, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the La content is preferably 0% by mass. The La content can be 0% by mass.

[0594] In the glass of the third embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the Gd content is preferably 1.0 mol%, and more preferably in the order of 0.9 mol% and 0.8 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the Gd content is preferably 0 mol%. The Gd content can be 0 mol%.

[0595] Furthermore, in the glass of the third embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the Gd content is preferably 4.77% by mass, and more preferably in the order of 4.29% by mass and 3.81% by mass. Additionally, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the Gd content is preferably 0% by mass. The Gd content can be 0% by mass.

[0596] In the glass of the third embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the Y content is preferably 2.0 mol%, and more preferably in the order of 1.8 mol%, 1.4 mol%, 1.0 mol%, 0.9 mol%, and 0.8 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the Y content is preferably 0 mol%.

[0597] Furthermore, in the glass of the third embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the Y content is preferably 5.39% by mass, and more preferably in the order of 4.85% by mass, 3.77% by mass, 2.69% by mass, 2.42% by mass, and 2.16% by mass. Additionally, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the Y content is preferably 0% by mass.

[0598] In the glass of the third embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the Lu content is preferably 1.0 mol%, and more preferably in the order of 0.9 mol% and 0.8 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the Lu content is preferably 0 mol%. The Lu content can be 0 mol%.

[0599] Furthermore, in the glass of the third embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the Lu content is preferably 5.30% by mass, more preferably in the order of 4.77% by mass and 4.24% by mass. Additionally, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the Lu content is preferably 0% by mass. The Lu content can be 0% by mass.

[0600] In the glass of the third embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the Yb content is preferably 1.0 mol%, and more preferably in the order of 0.9 mol% and 0.8 mol%. Furthermore, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the Yb content is preferably 0 mol%. The Yb content can be 0 mol%.

[0601] Furthermore, in the glass of the third embodiment, from the viewpoint of improving the meltability of the glass raw material and improving its stability upon reheating, the upper limit of the Yb content is preferably 5.24% by mass, and more preferably in the order of 4.72% by mass and 4.19% by mass. Additionally, from the viewpoint of maintaining the refractive index nd and maintaining chemical durability, the lower limit of the Yb content is preferably 0% by mass. The Yb content can be 0% by mass.

[0602] In the optical glass of the third embodiment, from the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the upper limit of the Zr content is preferably 1.0 mol%, and more preferably in the order of 0.5 mol%, 0.2 mol%, and 0.1 mol%. The lower limit of the Zr content is preferably 0 mol%. The Zr content can be 0 mol%.

[0603] Furthermore, in the optical glass of the third embodiment, from the viewpoint of improving the meltability of the glass raw material and improving the resistance to devitrification during melting, the upper limit of the Zr content is preferably 3.04% by mass, and more preferably in the order of 1.52% by mass, 0.61% by mass, and 0.30% by mass. The lower limit of the Zr content is preferably 0% by mass. The Zr content can be 0% by mass.

[0604] In the optical glass of the third embodiment, the content and ratio of glass components other than those described above can be the same as in this embodiment.

[0605] In the optical glass of the third embodiment, the glass properties can be the same as those of the present embodiment described above.

[0606] The manufacturing of optical glass, optical element blanks, and optical elements in the third embodiment can also be the same as in this embodiment described above.

[0607] Example

[0608] The present invention will now be described in more detail with reference to the embodiments. However, the present invention is not limited to the implementation methods shown in the embodiments.

[0609] (Example 1)

[0610] Glass samples with the glass compositions shown in Tables 1-1(1), 1-1(2), 1-1(3), 1-2(1), 1-2(2), 1-2(3), 1-3(1), 1-3(2), 1-3(3)), 2-1(1), 2-1(2), 2-1(3), 2-1(4), 2-2(1), 2-2(2), 2-2(3), 2-2(4), 2-3(1), 2-3(2), 2-3(3), 2-3(4)), and A(1), A(2), A(3)) were prepared in the following order and various evaluations were performed. It should be noted that in Tables 1 and A, the glass composition is expressed in mole percent (%). Mole percent refers to the mole percentage when the total content of all elements in the glass is set to 100%. In Table 2, the glass composition is expressed as mass % (%). Mass % refers to the percentage by mass when the total content of all elements in the glass is set to 100%. While the methods of representing glass composition differ in Tables 1 and 2, optical glasses with the same sample number refer to identical optical glasses with the same composition. Therefore, Tables 1 and 2 show substantially the same optical glasses and their results.

[0611] It should be noted that Tables 1-1(1), 1-1(2), 1-1(3), 2-1(1), 2-1(2), 2-1(3), and 2-1(4) correspond to the first embodiment. Tables 1-2(1), 1-2(2), 1-2(3), 2-2(1), 2-2(2), 2-2(3), and 2-2(4) correspond to the second embodiment. Tables 1-3(1), 1-3(2), 1-3(3), 2-3(1), 2-3(2), 2-3(3), and 2-3(4) correspond to the third embodiment. In addition, the sample numbers A1 to A3 in Table A correspond to the third embodiment.

[0612] Manufacturing of optical glass

[0613] First, oxides, hydroxides, fluorides, chlorides, carbonates, and nitrates corresponding to the components of glass are prepared as raw materials. The raw materials are weighed and mixed thoroughly to achieve the glass composition shown in Tables 1 and 2. The resulting mixed raw materials (batch raw materials) are then placed in a platinum crucible and heated at 800°C–1000°C for 0.5–2 hours to produce molten glass. The mixture is stirred to achieve homogenization and clarified. The molten glass is then cast into a mold preheated to an appropriate temperature. The cast glass is then heat-treated at a temperature 50°C higher than the glass transition temperature (Tg) to 100°C lower than Tg for 15–120 minutes, and then naturally cooled to room temperature in a furnace to obtain a glass sample.

[0614] [Determination of optical properties]

[0615] The obtained glass samples were further annealed for approximately 15 to 120 minutes near the glass transition temperature Tg, and then cooled to room temperature in a furnace at a cooling rate of -30°C / hour to obtain annealed samples. The refractive index nd, Abbe number νd, and ΔT of the annealed samples were measured as described below.

[0616] (i) Refractive index nd and Abbe number νd

[0617] For the annealed samples mentioned above, the refractive indices nd, nF, and nC were determined by the refractive index determination method according to JIS standard JIS B 7071-1, and the Abbe number νd was calculated based on the following formula.

[0618] νd=(nd-1) / (nF-nC)

[0619] (ii) Stabilization index ΔT(Tx-Tg)

[0620] For the annealed samples described above, the glass transition temperature (Tg) and the rise temperature (Tx) of the exothermic crystallization peak were determined using a differential scanning calorimeter (DSC3300S) manufactured by NETZSCH Japan. The annealed samples were pulverized, and approximately 0.02 cc of the sample was measured and placed in a φ5 mm Pt pan. Measurements were performed at a heating rate of 10 °C / min and a maximum temperature of 1000 °C. Alumina (Al₂O₃) was used as the standard sample.

[0621] [Stability during reheating]

[0622] A glass specimen measuring 10 mm × 10 mm × 7.5 mm was subjected to a first heating for 10 minutes in a test furnace set / held at a temperature within the range of the glass transition temperature Tg to 5°C higher than Tg (Tg to Tg+5°C). A second heating was then performed for 10 minutes in a test furnace set / held at a temperature 130–160°C higher than the glass transition temperature Tg. During both heating processes, the glass specimen was placed on an alumina plate containing alumina powder, and the specimen was transported along with the plate. The specimen was then allowed to cool naturally to room temperature in the atmosphere. The presence or absence of crystallization was confirmed by microscopic observation of the glass interior. Furthermore, the overall devitrification of the glass was confirmed by visual inspection, and the following criteria were used for evaluation.

[0623] A: During the secondary heating, softening occurred at a temperature Tg +160℃. No crystallization was observed under a microscope.

[0624] B: Softening occurred during secondary heating at a temperature Tg +150℃. No crystallization was observed under a microscope.

[0625] C: Softening occurs during secondary heating at a temperature of Tg +130℃. No crystallization was observed under a microscope.

[0626] D: Softening occurs during secondary heating at a temperature Tg +130℃. Crystallization is observed under a microscope. No overall devitrification of the glass is observed with the naked eye.

[0627] E: During the secondary heating, at a temperature of Tg+130℃, no softening occurred due to surface and internal crystallization.

[0628]

[0629]

[0630]

[0631]

[0632]

[0633]

[0634]

[0635]

[0636]

[0637]

[0638]

[0639]

[0640]

[0641]

[0642]

[0643]

[0644]

[0645]

[0646]

[0647]

[0648]

[0649]

[0650]

[0651]

[0652] (Example 2)

[0653] Using the optical glass produced 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.

[0654] 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.

[0655] Various lenses, when combined with lenses made of other types of optical glass, can effectively correct high-order chromatic aberrations.

[0656] Furthermore, due to the low specific gravity of glass, each lens is lighter than a lens of the same optical properties and size, making it suitable for various imaging devices, especially for energy-saving applications, such as autofocus imaging devices. Similarly, prisms were fabricated using the various optical glasses produced in Example 1.

[0657] It should be understood that all the embodiments disclosed herein are exemplary and do not constitute a limitation. The scope of the invention is defined by the claims, not the foregoing description, and is intended to include all modifications within the meaning and scope of the claims.

[0658] For example, by adjusting the glass composition described in the instruction manual as exemplified above, an optical glass according to one embodiment of the present invention can be manufactured.

[0659] In addition, of course, any combination of two or more items exemplified in the specification or described as preferred items can be made.

Claims

1. An optical glass, wherein, the molar ratio [F / Al] of the content of F to the content of Al is 2.70 to 3.50, the molar ratio [Ba / P] of the content of Ba to the content of P is 0.100 to 1.10, the molar ratio [P / Al] of the content of P to the content of Al is 1.50 to 1.75, the molar ratio [O / P] of the content of O to the content of P is 3.55 to 4.00, the molar ratio [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] of the total content of Sr and Ba to the total content of Mg, Ca, Sr, Ba and Zn is 0.750 to 0.970, the molar ratio [(Ba+Sr+Zn) / P] of the total content of Ba, Sr and Zn to the content of P is 1.20 or less, and the Abbe number vd is 68.0 or more.

2. An optical glass, wherein, the molar ratio [F / Al] of the content of F to the content of Al is 2.50 to 3.50, the molar ratio [Ba / P] of the content of Ba to the content of P is 0.250 to 1.20, the molar ratio [P / Al] of the content of P to the content of Al is 1.50 to 1.75, the molar ratio [O / P] of the content of O to the content of P is 3.55 to 3.80, the molar ratio [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] of the total content of Sr and Ba to the total content of Mg, Ca, Sr, Ba and Zn is 0.750 to 0.970, the molar ratio [(Ba+Sr+Zn) / P] of the total content of Ba, Sr and Zn to the content of P is 1.20 or less, and the Abbe number vd is 68.0 or more.

3. The optical glass according to claim 1 or 2, wherein, the lower limit of the molar ratio [(Ba+Sr+Zn) / P] is 0.700, and / or, the upper limit of the total content [Sr+Li] is 12 mol%, and / or, the lower limit of the molar ratio [(Ba+Sr) / P] is 0.700, and / or, the upper limit of the molar ratio [(Ba+Sr) / P] is 1.20, and / or, the lower limit of the content of O is 30 mol%, and / or, the upper limit of the content of O is 60 mol%, and / or, the lower limit of the content of F is 8 mol%, and / or, the upper limit of the content of F is 35 mol%, and / or, the lower limit of the content of P is 2.0 mol%, and / or, the upper limit of the content of P is 25 mol%, and / or, the lower limit of the content of Al is 1.0 mol%, and / or, the upper limit of the content of Al is 18 mol%, and / or, the upper limit of the content of B is 10 mol%, and / or, the upper limit of the content of Li is 10 mol%, and / or, the upper limit of the content of Na is 10 mol%, and / or, the upper limit of the content of K is 10 mol%, and / or, the upper limit of the content of Mg is 10 mol%, and / or, the upper limit of the content of Ca is 10 mol%, and / or, the upper limit of the content of Sr is 10 mol%, and / or, the lower limit of the content of Ba is 1 mol%, and / or, the upper limit of the content of Ba is 20 mol%, and / or, the upper limit of the content of Zn is 10 mol%, and / or, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ the upper limit of the content of La is 8 mol%, and / or, the upper limit of the content of Gd is 4.0 mol%, and / or, the upper limit of the content of Y is 8 mol%, and / or, the upper limit of the content of Lu is 4.0 mol%, and / or, the upper limit of the content of Yb is 4.0 mol%, and / or, the upper limit of the content of Nb is 0.90 mol%, and / or, the upper limit of the content of Zr is 10 mol%.

4. The optical glass according to claim 1 or 2, wherein, the lower limit of the molar ratio [P / Al] is 1.51, and / or, the lower limit of the molar ratio [(Ba+Sr+Zn) / P] is 0.800, and / or, the upper limit of the total content [Sr+Li] is 8 mol%, and / or, the lower limit of the molar ratio [(Ba+Sr) / P] is 0.770, and / or, the upper limit of the molar ratio [(Ba+Sr) / P] is 1.10, and / or, the lower limit of the content of O is 35 mol%, and / or, the upper limit of the content of O is 52 mol%, and / or, the lower limit of the content of F is 16 mol%, and / or, the upper limit of the content of F is 29 mol%, and / or, the lower limit of the content of P is 6.0 mol%, and / or, the upper limit of the content of P is 18 mol%, and / or, the lower limit of the content of Al is 3.0 mol%, and / or, the upper limit of the content of Al is 11 mol%, and / or, the upper limit of the content of B is 6 mol%, and / or, the upper limit of the content of Li is 6 mol%, and / or, the upper limit of the content of Na is 6 mol%, and / or, the upper limit of the content of K is 6 mol%, and / or, the upper limit of the content of Mg is 6 mol%, and / or, the upper limit of the content of Ca is 6 mol%, and / or, the upper limit of the content of Sr is 6 mol%, and / or, the lower limit of the content of Ba is 5 mol%, and / or, the upper limit of the content of Ba is 16 mol%, and / or, the upper limit of the content of Zn is 6 mol%, and / or, the upper limit of the content of La is 4 mol%, and / or, the upper limit of the content of Gd is 1.6 mol%, and / or, the upper limit of the content of Y is 4 mol%, and / or, the upper limit of the content of Lu is 2.0 mol%, and / or, the upper limit of the content of Yb is 2.0 mol%, and / or, the lower limit of the content of Nb is 0.005 mol%, and / or, the upper limit of the content of Nb is 0.09 mol%, and / or, the upper limit of the content of Zr is 6 mol%.

5. The optical glass according to claim 1 or 2, wherein, the upper limit of the molar ratio [F / Al] is 3.40, and / or, the lower limit of the molar ratio [Ba / P] is 0.800, and / or, the upper limit of the molar ratio [Ba / P] is 1.00, and / or, the lower limit of the molar ratio [P / Al] is 1.53, and / or, the lower limit of the molar ratio [O / P] is 3.59, and / or, the lower limit of the molar ratio [(Ba+Sr+Zn) / P] is 0.900, and / or, the upper limit of the molar ratio [(Ba+Sr+Zn) / P] is 1.10, and / or, the upper limit of the total content [Sr+Li] is 5 mol%, and / or, the lower limit of the molar ratio [(Ba + Sr) / P] is 0.800, and / or, the upper limit of the molar ratio [(Ba + Sr) / P] is 1.00, and / or, the lower limit of the content of O is 38 mol%, and / or, the upper limit of the content of O is 48 mol%, and / or, the lower limit of the content of F is 18 mol%, and / or, the upper limit of the content of F is 27 mol%, and / or, the lower limit of the content of P is 9.0 mol%, and / or, the upper limit of the content of P is 13 mol%, and / or, the lower limit of the content of Al is 5.0 mol%, and / or, the upper limit of the content of Al is 9 mol%, and / or, the upper limit of the content of B is 2 mol%, and / or, the upper limit of the content of Li is 2 mol%, and / or, the upper limit of the content of Na is 2 mol%, and / or, the upper limit of the content of K is 2 mol%, and / or, the upper limit of the content of Mg is 2 mol%, and / or, the upper limit of the content of Ca is 2 mol%, and / or, the upper limit of the content of Sr is 2 mol%, and / or, the lower limit of the content of Ba is 8 mol%, and / or, the upper limit of the content of Ba is 12 mol%, and / or, the upper limit of the content of Zn is 2 mol%, and / or, the upper limit of the content of La is 1 mol%, and / or, the upper limit of the content of Gd is 0.2 mol%, and / or, the upper limit of the content of Y is 1 mol%, and / or, the upper limit of the content of Lu is 0.2 mol%, and / or, the upper limit of the content of Yb is 0.2 mol%, and / or, the lower limit of the content of Nb is 0.009 mol%, and / or, the upper limit of the content of Nb is 0.02 mol%, and / or, the upper limit of the content of Zr is 2 mol%.

6. An optical glass, wherein, the molar ratio [F / Al] of the content of F to the content of Al is 4.60 to 6.00, the molar ratio [Ba / P] of the content of Ba to the content of P is 0.100 to 1.05, the molar ratio [P / Al] of the content of P to the content of Al is 0.450 to 0.700, the molar ratio [O / P] of the content of O to the content of P is 3.60 to 4.20, the molar ratio [F / (O + F + Cl)] of the content of F to the total content of O, F and Cl is 0.010 to 0.790, the molar ratio [(Sr + Ba) / (Mg + Ca + Sr + Ba + Zn)] of the total content of Sr and Ba to the total content of Mg, Ca, Sr, Ba and Zn is 0.00 to 0.67, the molar ratio [(Ba + Sr + Zn) / P] of the total content of Ba, Sr and Zn to the content of P is 2.1 or less, the content of Nb is 0.02 mol% or less, the content of Ti is 0.4 mol% or less, the content of W is 0.4 mol% or less, the Abbe number vd is 82.95 or more.

7. An optical glass, wherein, the molar ratio [F / Al] of the content of F to the content of Al is 4.60 to 6.00, the molar ratio [Ba / P] of the content of Ba to the content of P is 0.100 to 1.05, the molar ratio [P / Al] of the content of P to the content of Al is 0.450 to 0.700, the molar ratio of the content of O to the content of P [O / P] is 3.60 to 4.20, the molar ratio of the content of F to the total content of O, F, and Cl [F / (O+F+Cl)] is 0.010 to 0.790, the total content of Li, Na, and K [Li+Na+K] is 0.00 to 5.00 mol%, the molar ratio of the total content of Ba, Sr, and Zn to the content of P [(Ba+Sr+Zn) / P] is 1.4 to 2.1, the content of Nb is 0.02 mol% or less, the content of Ti is 0.4 mol% or less, the content of W is 0.4 mol% or less, the Abbe number vd is 82.95 or more.

8. The optical glass according to claim 6 or 7, wherein, the upper limit of the total content [Y+La+Gd+Yb+Lu] is 1.62 mol%, and / or, the lower limit of the molar ratio [(Ba+Sr) / P] is 1.05, and / or, the upper limit of the molar ratio [(Ba+Sr) / P] is 2.25, and / or, the lower limit of the content of O is 12 mol%, and / or, the upper limit of the content of O is 26 mol%, and / or, the lower limit of the content of F is 30 mol%, and / or, the upper limit of the content of F is 54 mol%, and / or, the upper limit of the content of Cl is 0.20 mol%, and / or, the lower limit of the content of P is 1.0 mol%, and / or, the upper limit of the content of P is 9.0 mol%, and / or, the lower limit of the content of Al is 7.0 mol%, and / or, the upper limit of the content of Al is 12 mol%, and / or, the upper limit of the content of B is 1.0 mol%, and / or, the upper limit of the content of Si is 1.0 mol%, and / or, the upper limit of the content of Li is 6.5 mol%, and / or, the upper limit of the content of Na is 2.0 mol%, and / or, the upper limit of the content of K is 2.0 mol%, and / or, the lower limit of the content of Mg is 0.3 mol%, and / or, the upper limit of the content of Mg is 5.0 mol%, and / or, the lower limit of the content of Ca is 2.0 mol%, and / or, the upper limit of the content of Ca is 9.0 mol%, and / or, the lower limit of the content of Sr is 1.0 mol%, and / or, the upper limit of the content of Sr is 7.2 mol%, and / or, the lower limit of the content of Ba is 1.0 mol%, and / or, the upper limit of the content of Ba is 7.2 mol%, and / or, the upper limit of the content of Zn is 1.0 mol%, and / or, the upper limit of the content of La is 1.0 mol%, and / or, the upper limit of the content of Gd is 1.0 mol%, and / or, the upper limit of the content of Y is 1.0 mol%, and / or, the upper limit of the content of Lu is 1.0 mol%, and / or, the upper limit of the content of Yb is 1.0 mol%, and / or, the upper limit of the content of Zr is 1.0 mol.

9. The optical glass according to claim 6 or 7, wherein, the lower limit of the molar ratio [F / Al] is 4.70, and / or, the lower limit of the molar ratio [Ba / P] is 0.400, and / or, the lower limit of the molar ratio [O / P] is 3.64, and / or, the upper limit of the molar ratio [O / P] is 4.00, and / or, a lower limit of the molar ratio [F / (O + F + Cl)] is 0.320, and / or, an upper limit of the molar ratio [F / (O + F + Cl)] is 0.760, and / or, a lower limit of the molar ratio [(Sr + Ba) / (Mg + Ca + Sr + Ba + Zn)] is 0.400, and / or, an upper limit of the molar ratio [(Sr + Ba) / (Mg + Ca + Sr + Ba + Zn)] is 0.640, and / or, a lower limit of the total content [Li + Na + K] of Li, Na, and K is 0.40 mol%, and / or, a lower limit of the total content [Y + La + Gd + Yb + Lu] is 0.10 mol%, and / or, an upper limit of the total content [Y + La + Gd + Yb + Lu] is 1.20 mol%, and / or, a lower limit of the molar ratio [(Ba + Sr) / P] is 1.25, and / or, an upper limit of the molar ratio [(Ba + Sr) / P] is 2.05, and / or, a lower limit of the content of O is 13 mol%, and / or, an upper limit of the content of O is 25 mol%, and / or, a lower limit of the content of F is 31 mol%, and / or, an upper limit of the content of F is 53 mol%, and / or, a lower limit of the content of Cl is 0.02 mol%, and / or, an upper limit of the content of Cl is 0.15 mol%, and / or, a lower limit of the content of P is 2.0 mol%, and / or, an upper limit of the content of P is 8.0 mol%, and / or, a lower limit of the content of Al is 7.5 mol%, and / or, an upper limit of the content of Al is 11.0 mol%, and / or, an upper limit of the content of B is 0.5 mol%, and / or, an upper limit of the content of Si is 0.5 mol%, and / or, an upper limit of the content of Li is 5.5 mol%, and / or, an upper limit of the content of Na is 1.0 mol%, and / or, an upper limit of the content of K is 1.0 mol%, and / or, a lower limit of the content of Mg is 0.6 mol%, and / or, an upper limit of the content of Mg is 4.0 mol%, and / or, a lower limit of the content of Ca is 2.5 mol%, and / or, an upper limit of the content of Ca is 8.5 mol%, and / or, a lower limit of the content of Sr is 1.4 mol%, and / or, an upper limit of the content of Sr is 6.8 mol%, and / or, a lower limit of the content of Ba is 1.4 mol%, and / or, an upper limit of the content of Ba is 6.8 mol%, and / or, an upper limit of the content of Zn is 0.5 mol%, and / or, an upper limit of the content of La is 0.9 mol%, and / or, an upper limit of the content of Gd is 0.9 mol%, and / or, an upper limit of the content of Y is 0.9 mol%, and / or, an upper limit of the content of Lu is 0.9 mol%, and / or, an upper limit of the content of Yb is 0.9 mol%, and / or, an upper limit of the content of Zr is 0.5 mol%.

10. The optical glass according to claim 6 or 7, wherein, a lower limit of the molar ratio [F / Al] is 4.80, and / or, a lower limit of the molar ratio [Ba / P] is 0.500, and / or, a lower limit of the molar ratio [O / P] is 3.66, and / or, an upper limit of the molar ratio [O / P] is 3.95, and / or, a lower limit of the molar ratio [F / (O+F+Cl)] is 0.650, and / or, an upper limit of the molar ratio [F / (O+F+Cl)] is 0.710, and / or, a lower limit of the molar ratio [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] is 0.500, and / or, an upper limit of the molar ratio [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] is 0.620, and / or, a lower limit of the total content [Li+Na+K] of Li, Na, and K is 0.60 mol%, and / or, a lower limit of the total content [Y+La+Gd+Yb+Lu] is 0.15 mol%, and / or, an upper limit of the total content [Y+La+Gd+Yb+Lu] is 1.00 mol%, and / or, a lower limit of the molar ratio [(Ba+Sr) / P] is 1.45, and / or, an upper limit of the molar ratio [(Ba+Sr) / P] is 1.85, and / or, a lower limit of the molar ratio [(Ba+Sr+Zn) / P] is 1.5, and / or, an upper limit of the molar ratio [(Ba+Sr+Zn) / P] is 1.9, and / or, a lower limit of the content of O is 14 mol%, and / or, an upper limit of the content of O is 24 mol%, and / or, a lower limit of the content of F is 32 mol%, and / or, an upper limit of the content of F is 52 mol%, and / or, a lower limit of the content of Cl is 0.04 mol%, and / or, an upper limit of the content of Cl is 0.10 mol%, and / or, a lower limit of the content of P is 3.2 mol%, and / or, an upper limit of the content of P is 6.5 mol%, and / or, a lower limit of the content of Al is 8.5 mol%, and / or, an upper limit of the content of Al is 10.0 mol%, and / or, an upper limit of the content of B is 0.1 mol%, and / or, an upper limit of the content of Si is 0.1 mol%, and / or, an upper limit of the content of Li is 5.0 mol%, and / or, an upper limit of the content of Na is 0.5 mol%, and / or, an upper limit of the content of K is 0.5 mol%, and / or, a lower limit of the content of Mg is 1.0 mol%, and / or, an upper limit of the content of Mg is 3.0 mol%, and / or, a lower limit of the content of Ca is 3.5 mol%, and / or, an upper limit of the content of Ca is 7.8 mol%, and / or, a lower limit of the content of Sr is 1.6 mol%, and / or, an upper limit of the content of Sr is 6.6 mol%, and / or, a lower limit of the content of Ba is 1.6 mol%, and / or, an upper limit of the content of Ba is 6.6 mol%, and / or, an upper limit of the content of Zn is 0.2 mol%, and / or, an upper limit of the content of La is 0.8 mol%, and / or, an upper limit of the content of Gd is 0.8 mol%, and / or, an upper limit of the content of Y is 0.8 mol%, and / or, an upper limit of the content of Lu is 0.8 mol%, and / or, an upper limit of the content of Yb is 0.8 mol%, and / or, an upper limit of the content of Zr is 0.1 mol%.

11. An optical glass, wherein, the molar ratio [F / Al] of the content of F to the content of Al is 4.60 to 6.5, the molar ratio [Ba / P] of the content of Ba to the content of P is 0.400 to 0.820, the molar ratio [P / Al] of the content of P to the content of Al is 0.200 to 0.850, the molar ratio [O / P] of the content of O to the content of P is 3.05 to 3.49, the molar ratio [F / (O+F+Cl)] of the content of F to the total content of O, F and Cl is 0.010 to 0.790, the molar ratio [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] of the total content of Sr and Ba to the total content of Mg, Ca, Sr, Ba and Zn is 0.00 to 0.620, the molar ratio [(Ba+Sr+Zn) / P] of the total content of Ba, Sr and Zn to the content of P is 1.50 or less.

12. The optical glass according to claim 11, wherein the total content [Li+Na+K] of Li, Na and K is 0.00 to 6.40 mol%.

13. The optical glass according to claim 11 or 12, wherein the upper limit of the total content [Y+La+Gd+Yb+Lu] is 2.0 mol%, and / or, the lower limit of the molar ratio [(Ba+Sr) / P] is 0.72, and / or, the upper limit of the molar ratio [(Ba+Sr) / P] is 1.70, and / or, the lower limit of the molar ratio [(Ba+Sr+Zn) / P] is 0.40, and / or, the lower limit of the content of O is 12 mol%, and / or, the upper limit of the content of O is 26 mol%, and / or, the lower limit of the content of F is 30 mol%, and / or, the upper limit of the content of F is 54 mol%, and / or, the upper limit of the content of Cl is 0.20 mol%, and / or, the lower limit of the content of P is 2.0 mol%, and / or, the upper limit of the content of P is 15 mol%, and / or, the lower limit of the content of Al is 3.0 mol%, and / or, the upper limit of the content of Al is 12 mol%, and / or, the upper limit of the content of B is 1.0 mol%, and / or, the upper limit of the content of Si is 1.0 mol%, and / or, the upper limit of the content of Li is 6.5 mol%, and / or, the upper limit of the content of Na is 2.0 mol%, and / or, the upper limit of the content of K is 2.0 mol%, and / or, the lower limit of the content of Mg is 0.3 mol%, and / or, the upper limit of the content of Mg is 5.0 mol%, and / or, the lower limit of the content of Ca is 2.0 mol%, and / or, the upper limit of the content of Ca is 9.0 mol%, and / or, the lower limit of the content of Sr is 1.0 mol%, and / or, the upper limit of the content of Sr is 7.2 mol%, and / or, the lower limit of the content of Ba is 1.0 mol%, and / or, the upper limit of the content of Ba is 7.2 mol%, and / or, the upper limit of the content of Zn is 1.0 mol%, and / or, the upper limit of the content of La is 1.0 mol%, and / or, the upper limit of the content of Gd is 1.0 mol%, and / or, the upper limit of the content of Y is 2.0 mol%, and / or, the upper limit of the content of Lu is 1.0 mol%, and / or, the upper limit of the content of Yb is 1.0 mol%, and / or, the upper limit of the content of Zr is 1.0 mol%.

14. The optical glass according to claim 11 or 12, wherein the lower limit of the molar ratio [F / Al] is 4.90, and / or, the lower limit of the molar ratio [Ba / P] is 0.420, and / or, the upper limit of the molar ratio [Ba / P] is 0.700, and / or, the lower limit of the molar ratio [P / Al] is 0.450, and / or, the lower limit of the molar ratio [O / P] is 3.09, and / or, the upper limit of the molar ratio [O / P] is 3.45, and / or, the lower limit of the molar ratio [F / (O+F+Cl)] is 0.500, and / or, the upper limit of the molar ratio [F / (O+F+Cl)] is 0.770, and / or, the lower limit of the molar ratio [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] is 0.400, and / or, the lower limit of the total content [Li+Na+K] is 0.40 mol%, and / or, the upper limit of the total content [Li+Na+K] is 6.00 mol%, and / or, the lower limit of the total content [Y+La+Gd+Yb+Lu] is 0.10 mol%, and / or, the upper limit of the total content [Y+La+Gd+Yb+Lu] is 1.4 mol%, and / or, the lower limit of the molar ratio [(Ba+Sr) / P] is 1.02, and / or, the upper limit of the molar ratio [(Ba+Sr) / P] is 1.58, and / or, the lower limit of the molar ratio [(Ba+Sr+Zn) / P] is 0.77, and / or, the lower limit of the content of O is 13 mol%, and / or, the upper limit of the content of O is 25 mol%, and / or, the lower limit of the content of F is 31 mol%, and / or, the upper limit of the content of F is 53 mol%, and / or, the lower limit of the content of Cl is 0.02 mol%, and / or, the upper limit of the content of Cl is 0.15 mol%, and / or, the lower limit of the content of P is 3.0 mol%, and / or, the upper limit of the content of P is 12 mol%, and / or, the lower limit of the content of Al is 5.0 mol%, and / or, the upper limit of the content of Al is 11.0 mol%, and / or, the upper limit of the content of B is 0.5 mol%, and / or, the upper limit of the content of Si is 0.5 mol%, and / or, the upper limit of the content of Li is 5.5 mol%, and / or, the upper limit of the content of Na is 1.0 mol%, and / or, the upper limit of the content of K is 1.0 mol%, and / or, the lower limit of the content of Mg is 0.6 mol%, and / or, the upper limit of the content of Mg is 3.5 mol%, and / or, the lower limit of the content of Ca is 2.5 mol%, and / or, the upper limit of the content of Ca is 8.0 mol%, and / or, the lower limit of the content of Sr is 1.2 mol%, and / or, the upper limit of the content of Sr is 6.6 mol%, and / or, the lower limit of the content of Ba is 1.2 mol%, and / or, the upper limit of the content of Ba is 5.0 mol%, and / or, the upper limit of the content of Zn is 0.5 mol%, and / or, The upper limit of the content of La is 0.9 mol%, and / or, The upper limit of the content of Gd is 0.9 mol%, and / or, The upper limit of the content of Y is 1.4 mol%, and / or, The upper limit of the content of Lu is 0.9 mol%, and / or, The upper limit of the content of Yb is 0.9 mol%, and / or, The upper limit of the content of Zr is 0.5 mol%.

15. The optical glass according to claim 11 or 12, wherein, The lower limit of the molar ratio [F / Al] is 5.20, and / or, The lower limit of the molar ratio [Ba / P] is 0.430, and / or, The upper limit of the molar ratio [Ba / P] is 0.600, and / or, The lower limit of the molar ratio [P / Al] is 0.550, and / or, The lower limit of the molar ratio [O / P] is 3.30, and / or, The upper limit of the molar ratio [O / P] is 3.40, and / or, The lower limit of the molar ratio [F / (O+F+Cl)] is 0.650, and / or, The upper limit of the molar ratio [F / (O+F+Cl)] is 0.750, and / or, The lower limit of the molar ratio [(Sr+Ba) / (Mg+Ca+Sr+Ba+Zn)] is 0.480, and / or, The lower limit of the total content [Li+Na+K] is 0.60 mol%, and / or, The upper limit of the total content [Li+Na+K] is 5.00 mol%, and / or, The lower limit of the total content [Y+La+Gd+Yb+Lu] is 0.15 mol%, and / or, The upper limit of the total content [Y+La+Gd+Yb+Lu] is 1.0 mol%, and / or, The lower limit of the molar ratio [(Ba+Sr) / P] is 1.12, and / or, The upper limit of the molar ratio [(Ba+Sr) / P] is 1.48, and / or, The lower limit of the molar ratio [(Ba+Sr+Zn) / P] is 1.07, and / or, The lower limit of the content of O is 14 mol%, and / or, The upper limit of the content of O is 24 mol%, and / or, The lower limit of the content of F is 32 mol%, and / or, The upper limit of the content of F is 52 mol%, and / or, The lower limit of the content of Cl is 0.04 mol%, and / or, The upper limit of the content of Cl is 0.10 mol%, and / or, The lower limit of the content of P is 4.5 mol%, and / or, The upper limit of the content of P is 9 mol%, and / or, The lower limit of the content of Al is 6.0 mol%, and / or, The upper limit of the content of Al is 10.0 mol%, and / or, The upper limit of the content of B is 0.1 mol%, and / or, The upper limit of the content of Si is 0.1 mol%, and / or, The upper limit of the content of Li is 5.0 mol%, and / or, The upper limit of the content of Na is 0.5 mol%, and / or, The upper limit of the content of K is 0.5 mol%, and / or, The lower limit of the content of Mg is 1.0 mol%, and / or, The upper limit of the content of Mg is 2.5 mol%, and / or, The lower limit of the content of Ca is 3.5 mol%, and / or, The upper limit of the content of Ca is 7.0 mol%, and / or, The lower limit of the content of Sr is 1.6 mol%, and / or, The upper limit of the content of Sr is 5.5 mol%, and / or, The lower limit for Ba content is 1.6 mol%, and / or, The upper limit for Ba content is 4.0 mol%, and / or, The upper limit for Zn content is 0.2 mol%, and / or, The upper limit for the content of La is 0.8 mol%, and / or, The upper limit for Gd content is 0.8 mol%, and / or, The upper limit for the content of Y is 0.8 mol%, and / or, The upper limit for the Lu content is 0.8 mol%, and / or, The upper limit for the Yb content is 0.8 mol%, and / or, The upper limit for Zr content is 0.1 mol.

16. The optical glass according to any one of claims 1, 2, 6, 7, 11, and 12, wherein, The upper limit for the total [Li+Na] content is 10.0 mol%, and / or, The upper limit for the total content of [Sr+Li] is 11.4 mol%, and / or, The upper limit for the total content [Y+La+Gd+Yb+Lu] is 2.0 mol%, and / or, The upper limit for the Cl content is 2.40 mol%, and / or, The upper limit for the Si content is 1.60 mol%, and / or, The upper limit for the Cs content is 1.60 mol%, and / or, The lower limit for the total content [Mg+Ca+Sr+Ba+Zn] is 8.0 mol%, and / or, The upper limit for the total content [Mg+Ca+Sr+Ba+Zn] is 25.0 mol%, and / or, The lower limit for the total content [Sr+Ba+Zn] is 3.0 mol%, and / or, The upper limit for the total content [Sr+Ba+Zn] is 20.0 mol%, and / or, The lower limit for the total content [Sr+Ba] is 2.8 mol%, and / or, The upper limit for the total content [Sr+Ba] is 19.8 mol%, and / or, The upper limit for the Bi content is 2.0 mol%, and / or, The upper limit for Ta content is 2.0 mol%, and / or, The upper limit for the content of Sc is 2 mol%, and / or, The upper limit for Hf content is 2 mol%, and / or, The upper limit for the Ge content is 2 mol%, and / or, The total content of O, F, P, Al, Ba, B, Si, Li, Na, K, Cs, Mg, Ca, Sr, Zn, La, Gd, Y, Lu, Yb, Nb, Ti, W, Bi, Zr, Ta, Sc, Hf, and Ge is 95 mol% or more, and / or The upper limit for Sb content is 0.20 mol%, based on the amount added, and / or, The content of each of Cu, Co, Ni, Fe, Cr, Eu, Nd, Er, and V is less than 100 ppm by mass, and / or, The content of each of Ga, Te, and Tb is 0 to 0.1 mol.

17. The optical glass according to any one of claims 1, 2, 6, 7, 11, and 12, wherein, The lower limit for the total [Li+Na] content is 0.03 mol%, and / or, The upper limit for the total [Li+Na] content is 7.0 mol%, and / or, The lower limit for the total content [Li+Na+K] is 0.08 mol%, and / or, The lower limit of the molar ratio [F / (O+F+Cl)] is 0.280, and / or, the lower limit of the total content [Sr + Li] is 0.6 mol%, and / or, the upper limit of the total content [Sr + Li] is 3.6 mol%, and / or, the lower limit of the total content [Y + La + Gd + Yb + Lu] is 0.20 mol%, and / or, the upper limit of the total content [Y + La + Gd + Yb + Lu] is 1.2 mol%, and / or, the lower limit of the content of Cl is 0.03 mol%, and / or, the upper limit of the content of Cl is 0.32 mol%, and / or, the upper limit of the content of Si is 0.80 mol%, and / or, the upper limit of the content of Cs is 0.80 mol%, and / or, the lower limit of the total content [Mg + Ca + Sr + Ba + Zn] is 11.0 mol%, and / or, the upper limit of the total content [Mg + Ca + Sr + Ba + Zn] is 21.0 mol%, and / or, the lower limit of the total content [Sr + Ba + Zn] is 6.0 mol%, and / or, the upper limit of the total content [Sr + Ba + Zn] is 14.0 mol%, and / or, the lower limit of the total content [Sr + Ba] is 5.8 mol%, and / or, the upper limit of the total content [Sr + Ba] is 13.8 mol%, and / or, the lower limit of the content of Nb is 0.004 mol%, and / or, the upper limit of the content of Bi is 1.2 mol%, and / or, the upper limit of the content of Ta is 1.2 mol%, and / or, the total content of O, F, P, Al, Ba, B, Si, Li, Na, K, Cs, Mg, Ca, Sr, Zn, La, Gd, Y, Lu, Yb, Nb, Ti, W, Bi, Zr, Ta, Sc, Hf, and Ge is 98 mol% or more, and / or, the upper limit of the content of Sb is 0.01 mol%, which is an additive amount, and / or, each content of Cu, Co, Ni, Fe, Cr, Eu, Nd, Er, and V is 0 to 50 mass ppm, and / or, each content of Ga, Te, and Tb is 0 to 0.01 mol%.

18. The optical glass according to any one of claims 1, 2, 11 and 12, wherein the lower limit of the molar ratio [Ba / P] is 0.500, and / or, the upper limit of the molar ratio [Ba / P] is 0.600, and / or, the lower limit of the total content [Li + Na] is 0.10 mol%, and / or, the upper limit of the total content [Li + Na] is 3.0 mol%, and / or, the lower limit of the total content [Li + Na + K] is 0.18 mol%, and / or, the upper limit of the total content [Li + Na + K] is 4.40 mol%, and / or, the lower limit of the molar ratio [F / (O + F + Cl)] is 0.550, and / or, the upper limit of the molar ratio [F / (O + F + Cl)] is 0.600, and / or, the lower limit of the total content [Sr + Li] is 1.2 mol%, and / or, the upper limit of the total content [Sr + Li] is 1.8 mol%, and / or, the lower limit of the total content [Y + La + Gd + Yb + Lu] is 0.40 mol%, and / or, the upper limit of the content of Y+La+Gd+Yb+Lu is 0.80 mol%, and / or, the lower limit of the content of Cl is 0.05 mol%, and / or, the upper limit of the content of Cl is 0.16 mol%, and / or, the upper limit of the content of Si is 0.20 mol%, and / or, the upper limit of the content of Cs is 0.20 mol%, and / or, the lower limit of the total content [Mg+Ca+Sr+Ba+Zn] is 12.0 mol%, and / or, the upper limit of the total content [Mg+Ca+Sr+Ba+Zn] is 17.0 mol%, and / or, the lower limit of the total content [Sr+Ba+Zn] is 8.0 mol%, and / or, the upper limit of the total content [Sr+Ba+Zn] is 12.0 mol%, and / or, the lower limit of the total content [Sr+Ba] is 7.8 mol%, and / or, the upper limit of the total content [Sr+Ba] is 11.8 mol%, and / or, the lower limit of the content of Nb is 0.008 mol%, and / or, the upper limit of the content of Nb is 0.02 mol%, and / or, the upper limit of the content of Ti is 0.4 mol%, and / or, the upper limit of the content of W is 0.4 mol%, and / or, the upper limit of the content of Bi is 0.4 mol%, and / or, the upper limit of the content of Ta is 0.4 mol%, and / or, the total content of O, F, P, Al, Ba, B, Si, Li, Na, K, Cs, Mg, Ca, Sr, Zn, La, Gd, Y, Lu, Yb, Nb, Ti, W, Bi, Zr, Ta, Sc, Hf, and Ge is 99.5 mol% or more, and / or, the upper limit of the content of Sb is 0.002 mol%, which is an additive amount, and / or, substantially not containing Cu, Co, Ni, Fe, Cr, Eu, Nd, Er, and V, and / or, each of the contents of Ga, Te, and Tb is 0 to 0.001 mol%.

19. The optical glass according to claim 6 or 7, wherein the lower limit of the molar ratio [Ba / P] is 0.500, and / or, the upper limit of the molar ratio [Ba / P] is 0.600, and / or, the lower limit of the total content [Li+Na] is 0.10 mol%, and / or, the upper limit of the total content [Li+Na] is 3.0 mol%, and / or, the lower limit of the total content [Li+Na+K] is 0.18 mol%, and / or, the upper limit of the total content [Li+Na+K] is 4.40 mol%, and / or, the lower limit of the molar ratio [F / (O+F+Cl)] is 0.550, and / or, the upper limit of the molar ratio [F / (O+F+Cl)] is 0.600, and / or, the lower limit of the total content [Sr+Li] is 1.2 mol%, and / or, the upper limit of the total content [Sr+Li] is 1.8 mol%, and / or, the lower limit of the total content [Y+La+Gd+Yb+Lu] is 0.40 mol%, and / or, the upper limit of the total content [Y+La+Gd+Yb+Lu] is 0.80 mol%, and / or, the upper limit of the total content [Y+La+Gd+Yb+Lu] is 0.80 mol%, and / or, the lower limit of the content of Cl is 0.05 mol%, and / or, the upper limit of the content of Cl is 0.16 mol%, and / or, the upper limit of the content of Si is 0.20 mol%, and / or, the upper limit of the content of Cs is 0.20 mol%, and / or, the lower limit of the total content [Mg + Ca + Sr + Ba + Zn] is 12.0 mol%, and / or, the upper limit of the total content [Mg + Ca + Sr + Ba + Zn] is 17.0 mol%, and / or, the lower limit of the total content [Sr + Ba + Zn] is 8.0 mol%, and / or, the upper limit of the total content [Sr + Ba + Zn] is 12.0 mol%, and / or, the lower limit of the total content [Sr + Ba] is 7.8 mol%, and / or, the upper limit of the total content [Sr + Ba] is 11.8 mol%, and / or, the lower limit of the content of Nb is 0.008 mol%, and / or, the upper limit of the content of Bi is 0.4 mol%, and / or, the upper limit of the content of Ta is 0.4 mol%, and / or, the total content of O, F, P, Al, Ba, B, Si, Li, Na, K, Cs, Mg, Ca, Sr, Zn, La, Gd, Y, Lu, Yb, Nb, Ti, W, Bi, Zr, Ta, Sc, Hf, and Ge is 99.5 mol% or more, and / or, the upper limit of the content of Sb is 0.002 mol%, which is an additive amount, and / or, substantially not containing Cu, Co, Ni, Fe, Cr, Eu, Nd, Er, and V, and / or, each of the contents of Ga, Te, and Tb is 0 to 0.001 mol%.

20. The optical glass according to any one of claims 1, 2, 6, 7, 11, and 12, wherein the upper limit of Abbe number vd is 94, and / or the lower limit of refractive index nd is 1.30, and / or the upper limit of refractive index nd is 1.65, and / or no opalescence occurs when heated for 10 minutes in a test furnace set to a temperature of 130 to 160°C higher than the glass transition temperature Tg, and / or the lower limit of specific gravity is 3.50, and / or the upper limit of specific gravity is 4.25, and / or the lower limit of glass transition temperature Tg is 380°C, and / or the upper limit of glass transition temperature Tg is 550°C, and / or the lower limit of stabilization index AT of the difference (Tx - Tg) between the rise temperature Tx of the exothermic peak of crystallization and the glass transition temperature Tg is 100°C, and / or the upper limit of stabilization index AT of the difference (Tx - Tg) between the rise temperature Tx of the exothermic peak of crystallization and the glass transition temperature Tg is 300°C.

21. The optical glass according to any one of claims 1, 2, 6, 7, 11, and 12, wherein the lower limit of refractive index nd is 1.42, and / or the upper limit of refractive index nd is 1.55, and / or no crystallization is confirmed even when the inside of the glass is observed with a microscope when heated for 10 minutes in a test furnace set to a temperature of 130 to 160°C higher than the glass transition temperature Tg, and / or the upper limit of specific gravity is 4.20, and / or the upper limit of the glass transition temperature Tg is 535°C, and / or, the lower limit of the stabilization index ΔT of the difference (Tx-Tg) between the exothermic peak temperature Tx of crystallization and the glass transition temperature Tg is 120°C.

22. The optical glass according to any one of claims 1, 2, 6, 7, 11 and 12, wherein, the lower limit of the refractive index nd is 1.45, and / or, the upper limit of the refractive index nd is 1.50, and / or, crystals are not precipitated in the interior of the glass when heated in a test furnace set to a temperature 130 to 160°C higher than the glass transition temperature Tg for 10 minutes, and / or, the upper limit of the specific gravity is 4.15, and / or, the upper limit of the glass transition temperature Tg is 520°C, and / or, the lower limit of the stabilization index ΔT of the difference (Tx-Tg) between the exothermic peak temperature Tx of crystallization and the glass transition temperature Tg is 130°C.

23. An optical element blank made of the optical glass according to any one of claims 1 to 22.

24. A press-molding glass material made of the optical glass according to any one of claims 1 to 22.

25. An optical element made of the optical glass according to any one of claims 1 to 22.

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