Optical Glass and Optical Elements

Abstract

[Problem] To provide: an optical glass that has desired optical constants and suppressed deterioration of mechanical properties, and does not have a high glass transition temperature; and an optical element. [Solution] An optical glass has an Abbe number νd of at least 62.00, the content of B3+ being 0 cation% to 50.00 cation% (exclusive of 0 cation%), the content of Si4+ being more than 0 cation%, the content of F- being more than 0 anion%, and the total content [La3++Gd3++Y3+] of La3+, Gd3+, and Y3+ being at least 5 cation%.

Description

[Technical Field]

[0001] The present invention relates to optical glasses and optical elements having desirable optical properties. [Background technology]

[0002] Lenses with high refractive indices and anomalous partial dispersion in each Abbe region are widely used in applications such as in-vehicle cameras, digital cameras such as single-lens reflex cameras, and personal digital assistant devices such as smartphones. For these applications, glass with high mechanical properties is desirable to improve the yield during lens production. Furthermore, for example, when processing glass into aspherical lenses, glass with a high glass transition temperature can be difficult to process. Therefore, glass with a lower glass transition temperature is desired.

[0003] In particular, focusing on lenses with an Abbe number νd of 62 or greater, conventionally, glasses with compositions containing P (phosphorus) as a network-forming component, such as P-Al-RO and P-Al-F, have been used as glasses with an Abbe number νd of 62 or greater and a relatively high refractive index nd. However, such glasses with compositions containing P (phosphorus) as a network-forming component have poor mechanical properties, resulting in problems such as a decrease in yield in the lens processing process and a deterioration in product quality. Furthermore, with glasses with compositions containing Si (silicon) as a network-forming component, it is difficult to incorporate large amounts of glass components that contribute to high refractive index and low dispersion, making it difficult to achieve the desired optical constants, such as an Abbe number νd of 62 or greater and a high refractive index nd.

[0004] Therefore, the present invention focused on B-La-F type glasses. Conventionally, in B-La-F type glasses, many of the components that contribute to low dispersion of the glass volatilize during melting, making it difficult to increase the Abbe number νd. In the present invention, the volatilization of glass components is suppressed by adjusting the glass composition, resulting in the invention of a glass with an Abbe number νd of 62 or more and excellent mechanical properties.

[0005] Patent Document 1 discloses fluorine-containing optical glass that has a large Abbe number relative to the refractive index and excellent resistance to devitrification. Patent Document 2 discloses optical glass that has a high refractive index and high transmittance in the near-infrared region. However, Patent Documents 1 and 2 do not disclose optical glass with an Abbe number νd of 62 or higher. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 56-169150 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-19670 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above circumstances, and has as its object to provide an optical glass and optical element that have desired optical constants, are inhibited from decreasing in mechanical properties, and do not have a high glass transition temperature. [Means for solving the problem]

[0008] The gist of the present invention is as follows.

[0009] (1) The Abbe number νd is 62.00 or more, B 3+ The content of is more than 0 cation% and 50.00 cation% or less, Si 4+ The content of exceeds 0 cation%, F - The content of exceeds 0% anion, La 3+ , Gd 3+ , and Y 3+ The total content of [La 3+ +Gd 3+ +Y 3+ ] is 5 cation % or more, Optical glass.

[0010] (2) Si 4+ , B 3+ , P 5+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ , and Ta 5+ La relative to the total content 3+ , Gd 3+ , Y 3+ , Li + , Na + , K. + , Rb + , Cs + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ The cation ratio of the total content [(La 3+ +Gd 3+ +Y 3+ +Li + +Na + +K + +Rb + +Cs + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ) / (Si 4+ +B 3+ +P 5+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+ )] is 0.50 or more, The optical glass according to (1).

[0011] (3) The Abbe number νd is 62.00 or more; B 3+ The content of is more than 0 cation% and 50.00 cation% or less, F - The content of is more than 0 anion% and 85 anion% or less, La 3+ , Gd 3+ , and Y3+ The total content of [La 3+ +Gd 3+ +Y 3+ ] is 5 cation % or more, Si 4+ , B 3+ , P 5+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ , and Ta 5+ La relative to the total content 3+ , Gd 3+ , Y 3+ , Li + , Na + , K. + , Rb + , Cs + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ The cation ratio of the total content [(La 3+ +Gd 3+ +Y 3+ +Li + +Na + +K + +Rb + +Cs + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ) / (Si 4+ +B 3+ +P 5+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+ )] is 0.60 or more, Si 4+ , B 3+ , and P 5+ Si content relative to the total content 4+ and B 3+ The cation ratio of the total content [(Si 4+ +B 3+ ) / (Si 4+ +B 3+ +P 5+)] is 0.2 or more, Optical glass.

[0012] (4) The optical glass according to any one of (1) to (3), wherein the content of Sb ions is 1.0 mass ppm or more in terms of exclusive proportion.

[0013] (5) An optical glass according to any one of (1) to (3), in which the difference between the external transmittance at a wavelength of 700 nm and the external transmittance at a wavelength of 360 nm is 10% or less when the thickness is 10.0 mm±0.1 mm.

[0014] (6) A glass material for press molding, comprising the optical glass according to any one of (1) to (3) above.

[0015] (7) An optical element made of the optical glass according to any one of (1) to (3) above. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide an optical glass and an optical element that have desired optical constants, are prevented from decreasing in mechanical properties, and have a moderate glass transition temperature. DETAILED DESCRIPTION OF THE INVENTION

[0017] In the embodiments of the present invention, the glass composition of the optical glass is expressed in cation % unless otherwise specified. Cation % is the molar percentage when the total content of all cationic components is taken as 100%. The contents and total content of glass components are based on cation % unless otherwise specified, and "%" means "cation %." Furthermore, the cation ratio refers to the ratio (ratio) of the contents of cationic components to each other (including the total content of multiple cationic components) in cation %.

[0018] The anion % is a molar percentage when the total content of all anion components is taken as 100%.

[0019] The valence of the cationic component (e.g., B 3+ The valence of is +3, Si4+ The valence of is +4, La 3+ The valence of the anion component (e.g., O) is a value established by convention, similar to the way that the glass components B, Si, and La are expressed on an oxide basis as B2O3, SiO2, and La2O3. Therefore, when analyzing glass composition, it is not necessary to analyze the valence of the cation component. Also, the valence of the anion component (e.g., O 2- The valence of an anion component (-2) is also a value determined by convention, similar to the way glass components based on oxides are expressed as B2O3, SiO2, La2O3, etc. Therefore, when analyzing glass composition, it is not necessary to analyze the valence of the anion component.

[0020] The content of glass components can be quantified by known methods, such as inductively coupled plasma atomic emission spectroscopy (ICP-AES), inductively coupled plasma mass spectroscopy (ICP-MS), ion chromatography (IC), non-dispersive infrared spectroscopy (ND-IR), etc. In this specification and the present invention, a content of 0% of a component means that the component is substantially not contained, and it is acceptable for the component to be present at an unavoidable impurity level.

[0021] In this specification, chemical durability refers to excellent water resistance Da and / or water resistance Dw. Furthermore, mechanical properties refer to excellent glass hardness, as measured by the Knoop hardness Hk. The Knoop hardness Hk is an index of the indentation hardness of glass. The Knoop hardness Hk is measured in units of "MPa." However, because it is customary to omit the unit of the Knoop hardness Hk in the technical field to which this invention pertains, the unit of the Knoop hardness Hk will also be omitted in this specification. Furthermore, the thermal stability and reheating stability of glass both refer to the resistance to crystal precipitation in the glass. Thermal stability refers to the resistance to crystal precipitation when molten glass solidifies, while reheating stability refers to the resistance to crystal precipitation when solidified glass is reheated, such as during reheat pressing.

[0022] As used herein, "reduced or suppressed volatilization of glass components" means that the loss of glass components due to volatilization during melting is small or suppressed. Small loss of glass components due to volatilization during melting suppresses fluctuations in various properties, including refractive index, and also suppresses the occurrence of internal defects such as striae within the glass, thereby stabilizing quality. Furthermore, low loss of glass components directly increases the product yield relative to the input raw materials. Meanwhile, glass components that are prone to volatilization during melting contribute to a decrease in dispersibility, an increase in anomalous partial dispersion, and a decrease in the glass transition temperature Tg. Therefore, suppressing the volatilization of these components can provide optical glasses and optical elements with desired optical constants and a moderate glass transition temperature Tg.

[0023] Unless otherwise specified, the refractive index refers to the refractive index nd at the d line of helium (wavelength 587.56 nm).

[0024] The optical glass of the present invention will be described below as a first embodiment and a second embodiment.

[0025] First embodiment The optical glass according to the first embodiment is The Abbe number νd is 62.00 or more, B 3+ The content of is more than 0 cation% and 50.00 cation% or less, Si 4+ The content of exceeds 0 cation%, F - The content of exceeds 0% anion, La 3+ , Gd 3+ , and Y 3+ The total content of [La 3+ +Gd 3+ +Y 3+ ] is 5 cation % or more.

[0026] <Abbe number νd> In the optical glass according to the first embodiment, the Abbe number vd is 62.00 or greater. The Abbe number vd is preferably 62-75, and can also be 62.2-73, 62.4-71, 62.6-69, 62.8-68, 63-67, or 62-63.

[0027] The Abbe number νd can be adjusted to a desired value by appropriately adjusting the content of each glass component. The component that relatively lowers the Abbe number νd, i.e., the high dispersion component, is Nb 5+ , Ti 4+ , Zr 4+ , W 6+ , Bi 3+ , Ta 5+ On the other hand, the component that relatively increases the Abbe number νd, that is, the low dispersion component, is F - , Si 4+ , B 3+ , Li + , Na + , K. + , La 3+ , Ba 2+ , Ca 2+ , Sr 2+ etc.

[0028] In the present invention, the Abbe number vd and the partial dispersion ratio Pg,F described below are calculated as follows. That is, the refractive index at the 12 wavelengths shown in Table A is measured according to Japanese Industrial Standards (JIS) JIS B 7071-1, Method for measuring the refractive index of optical glass - Part 1: Minimum deviation angle method. Next, the refractive index of each line obtained by the measurement is applied to the Schott dispersion formula defined in Annex B of Japanese Industrial Standards (JIS) JIS B 7071-1, Method for measuring the refractive index of optical glass - Part 1: Minimum deviation angle method, and the constants of the Schott dispersion formula are found by the least squares method. Then, the Abbe number vd and the partial dispersion ratio Pg,F described below are calculated from the values ​​of each linear refractive index obtained using the Schott dispersion formula with the determined constants.

[0029] [Table A] Shot dispersion formula: n 2 =a0+a1λ 2 +a2λ-2 +a3λ -4 +a4λ -6 +a5λ -8 Here, n is the refractive index, λ is the wavelength (μm), and a0, a1, a2, a3, a4, and a5 are constants. The Abbe number νd is expressed as follows using the refractive indices nd, nF, and nC at the d-line, F-line, and C-line, respectively: νd=(nd-1) / (nF-nC)

[0030] In the optical glass according to the first embodiment, B 3+ The content of is more than 0% and not more than 50.00%. 3+ The lower limit of the content of B is preferably 5%, and more preferably 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, and 21% in that order. 3+ The upper limit of the content is preferably 45.00%, and more preferably 40.00%, 39.00%, 38.00%, 37.00%, 36.00%, 35.00%, 34.00%, 33.00%, 32.00%, 31.00%, 30.00%, 29.00%, 28.00%, 27.00%, 26.00%, 25.00%, 24.00%, and 23.00% in that order.

[0031] B 3+ is a glass network forming component. 3+ By setting the content of B in the above range, chemical durability can be improved. 3+ If the content of B is too low, the thermal stability and mechanical properties of the glass may be reduced. 3+ If the content is too high, the volatilization of glass components may increase, and the thermal stability and chemical durability of the glass may decrease.

[0032] In the optical glass according to the first embodiment, Si 4+ The content of Si exceeds 0%. 4+ The lower limit of the content of Si is preferably 1%, and more preferably 2%, 3%, 4%, 5%, 6%, 7%, and 8% in that order. 4+The upper limit of the content is preferably 30%, and more preferably 25%, 23%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, and 10%, in that order.

[0033] Si 4+ is a glass network forming component. 4+ By setting the content of Si in the above range, an optical glass having anomalous partial dispersion and improved chemical durability, mechanical properties, and thermal stability can be obtained. 4+ If the Si content is too low, the chemical durability, mechanical properties, and thermal stability of the glass may be reduced. 4+ If the content is too high, the meltability of the glass may decrease, the refractive index nd may decrease, and the thermal stability of the glass may decrease, resulting in an increase in the glass transition temperature Tg.

[0034] The optical glass according to the first embodiment contains F as an anion component. - , i.e., F - The content of F is greater than 0%. - The lower limit of the content of is preferably 5 anion%, and more preferably 10 anion%, 15 anion%, 20 anion%, 24 anion%, 27 anion%, 30 anion%, 33 anion%, 35 anion%, 37 anion%, 39 anion%, 41 anion%, 43 anion%, 45 anion%, 46 anion%, 47 anion%, 48 anion%, 49 anion%, 50 anion%, 51 anion%, 52 anion%, 53 anion%, 54 anion%, 55 anion%, 56 anion%, and 57 anion% in that order. - The upper limit of the content of is preferably 80 anion%, and more preferably 77 anion%, 75 anion%, 73 anion%, 71 anion%, 69 anion%, 67 anion%, 65 anion%, 64 anion%, 63 anion%, 62 anion%, 61 anion%, 60 anion%, and 59 anion% in that order. -By setting the content of F within the above range, an optical glass can be obtained which has a high refractive index despite its low dispersion, high thermal stability, anomalous partial dispersion, a low glass transition temperature Tg, and is suitable for precision press molding. - If the content of F is too small, the thermal stability of the glass may decrease, and anomalous partial dispersion may not be obtained. - If the content is too large, the volatilization of glass components may increase.

[0035] In the optical glass according to the first embodiment, La 3+ , Gd 3+ , and Y 3+ The total content of [La 3+ +Gd 3+ +Y 3+ ] is 5% or more. The lower limit of the total content is preferably 10%, and more preferably 15%, 20%, 25%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, and 38% in that order. The upper limit of the total content is preferably 60%, and more preferably 55%, 50%, 48%, 46%, 45%, 44%, 43%, 42%, and 41% in that order. By keeping the total content within the above range, an optical glass with a high refractive index nd can be obtained. On the other hand, if the total content is too low, the desired optical constants may not be obtained. If the total content is too high, the thermal stability of the glass may be reduced.

[0036] Non-limiting examples of the contents of glass components other than those described above and the glass properties of the optical glass according to the first embodiment are shown below.

[0037] In the optical glass according to the first embodiment, Si 4+ and B 3+ The total content of [Si 4+ +B 3+The lower limit of

[0045] is preferably 10%, and more preferably 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 29%, and 30% in that order. The upper limit of the total content is preferably 70%, and more preferably 65%, 60%, 58%, 56%, 54%, 52%, 50%, 48%, 47%, 46%, 45%, 44%, 43%, 42%, 41%, 40%, 39%, 38%, 37%, 36%, 35%, 34%, 33%, and 32% in that order. Setting the total content within the above range is preferred from the viewpoint of obtaining an optical glass that has desired optical constants and anomalous partial dispersion, improved chemical durability, mechanical properties, and thermal stability, and suppresses volatilization of glass components during melting.

[0038] In the optical glass according to this embodiment, Li + , Na + , and K. + The total content of [Li + +Na + +K + The lower limit of [0% by weight] is preferably 0%, and more preferably 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, and 11% in that order. The upper limit of the total content is preferably 50%, and more preferably 45%, 40%, 35%, 30%, 25%, 20%, 18%, 16%, 14%, and 13% in that order. From the viewpoint of lowering the liquidus temperature of the glass and lowering the glass transition temperature Tg, it is preferable that the total content be within the above range.

[0039] In the optical glass according to the first embodiment, Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ The total content of [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+The lower limit of [0.01% by weight] is preferably 0%, and more preferably 1%, 3%, 5%, 7%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, and 16%, in that order. The upper limit of the total content is preferably 30%, and more preferably 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, and 19%, in that order. If the total content is too low, volatilization of the glass components may increase, and the thermal stability and devitrification resistance of the glass may decrease. If the total content is too high, the high refractive index may be impaired, and the thermal stability of the glass may be impaired. From the viewpoint of obtaining an optical glass having desired optical constants, reduced volatilization of the glass components, and high thermal stability, it is preferable that the total content be within the above range.

[0040] In the optical glass according to the first embodiment, Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ and Zn 2+ The total content of [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The upper limit of [% by weight] is preferably 50%, and more preferably 45%, 40%, 35%, 30%, 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, and 19%, in that order. The lower limit of the total content is preferably 0%, and more preferably 1%, 3%, 5%, 7%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, and 16%, in that order. If the total content is too high, the high refractive index may be impaired and the thermal stability of the glass may be impaired. On the other hand, if the total content is too low, the volatilization of the glass components may increase, and the thermal stability and devitrification resistance of the glass may be reduced. Therefore, the total content is preferably within the above range.

[0041] In the optical glass according to the first embodiment, Li + , Na + , K. + , Mg 2+ , Ca2+ , Sr 2+ , and Ba 2+ The total content of [Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The lower limit of [0% by weight] is preferably 0%, and more preferably 1%, 3%, 5%, 7%, 9%, 11%, 13%, 15%, 17%, 19%, 21%, 23%, 25%, and 27%, in that order. The upper limit of the total content is preferably 50%, and more preferably 45%, 42%, 40%, 39%, 38%, 37%, 36%, 35%, 34%, 33%, 32%, and 31%, in that order. From the viewpoint of obtaining an optical glass having desired optical constants, a reduced glass transition temperature Tg and glass liquidus temperature, and reduced volatilization of glass components during melting, it is preferable that the total content be within the above range.

[0042] In the optical glass according to the first embodiment, Li + , Na + , K. + , Rb + , Cs + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ The total content of [Li + +Na + +K + +Rb + +Cs + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+The lower limit of [0% by weight] is preferably 0%, and more preferably 1%, 3%, 5%, 7%, 9%, 11%, 13%, 15%, 17%, 19%, 21%, 23%, 25%, and 27%, in that order. The upper limit of the total content is preferably 50%, and more preferably 45%, 42%, 40%, 39%, 38%, 37%, 36%, 35%, 34%, 33%, 32%, and 31%, in that order. From the viewpoint of obtaining an optical glass that has desired optical constants, a reduced glass transition temperature Tg, reduced volatilization of glass components, and high thermal stability, it is preferable that the total content be within the above range.

[0043] In the optical glass according to the first embodiment, Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ The total content of [Ti 4+ +Nb 5+ +W 6+ +Bi 3+ The lower limit of [0.01% by mass] is preferably 0%, and more preferably 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, and 1.6%, in that order. The upper limit of the total content is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5%, in that order. From the viewpoint of maintaining high refractive index and low dispersion, the total content may be 0%. From the viewpoint of maintaining a desired Abbe number νd and improving anomalous partial dispersion in the visible to near-ultraviolet region, it is preferable that the total content be within the above range.

[0044] In the optical glass according to the first embodiment, Zr 4+ and Ta 5+ The total content of [Zr 4+ +Ta 5+The upper limit of [% by weight] is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3%, 2%, and 1% in that order. The lower limit of the total content is preferably 0%, and more preferably 0.1%, 0.2%, and 0.3% in that order. From the viewpoint of maintaining high refraction and low dispersion, the total content may be 0%. From the viewpoint of maintaining the thermal stability of the glass, it is preferable that the total content be within the above range. If the total content is too high, the thermal stability of the glass may be reduced and the raw material costs may increase.

[0045] In the optical glass according to the first embodiment, Ti 4+ , Nb 5+ , Bi 3+ , W 6+ , Zr 4+ , and Ta 5+ The total content of [Ti 4+ +Nb 5+ +Bi 3+ +W 6+ +Zr 4+ +Ta 5+ The upper limit of [% by mass] is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5% in that order. The lower limit of the total content is preferably 0%, and more preferably 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, and 1.6% in that order. From the viewpoint of maintaining high refractive index and low dispersion, the total content may be 0%. From the viewpoint of maintaining a desired Abbe number νd and improving anomalous partial dispersion in the visible to near-ultraviolet region, it is preferable that the total content be within the above range.

[0046] In the optical glass according to the first embodiment, Si 4+ and B 3+ Si content relative to the total content 4+ The cation ratio of the content [Si 4+ / (Si 4+ +B 3+The lower limit of the cation ratio is preferably 0.020, and more preferably 0.05, 0.09, 0.13, 0.15, 0.17, 0.19, 0.21, 0.22, 0.23, 0.24, and 0.25, in that order. The upper limit of the cation ratio is preferably 0.80, and more preferably 0.70, 0.60, 0.50, 0.40, 0.35, 0.34, 0.33, and 0.32, in that order. From the viewpoint of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferable that the cation ratio be within the above range.

[0047] In the optical glass according to the first embodiment, Si 4+ and B 3+ B relative to the total content of 3+ The content of cation ratio [B 3+ / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 0.980, and more preferably 0.95, 0.91, 0.87, 0.85, 0.83, 0.81, 0.79, 0.78, 0.77, 0.76, and 0.75, in that order. The lower limit of the cation ratio is preferably 0.20, and more preferably 0.30, 0.40, 0.50, 0.60, 0.65, 0.66, 0.67, and 0.68, in that order. From the viewpoint of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferable that the cation ratio be within the above range.

[0048] In the optical glass according to the first embodiment, Si 4+ , B 3+ , and P 5+ The total content of [Si 4+ +B 3+ +P 5+The lower limit of

[0045] is preferably 10%, and more preferably 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 29%, and 30% in that order. The upper limit of the total content is preferably 70%, and more preferably 65%, 60%, 58%, 56%, 54%, 52%, 50%, 48%, 47%, 46%, 45%, 44%, 43%, 42%, 41%, 40%, 39%, 38%, 37%, 36%, 35%, 34%, 33%, and 32% in that order. Setting the total content within the above range is preferred from the viewpoint of obtaining an optical glass that has desired optical constants and anomalous partial dispersion, improved chemical durability, mechanical properties, and thermal stability, and suppresses volatilization of glass components during melting.

[0049] In the optical glass according to the first embodiment, Si 4+ , B 3+ , and P 5+ Si content relative to the total content 4+ The cation ratio of the content [Si 4+ / (Si 4+ +B 3+ +P 5+ The upper limit of the cation ratio is preferably 0.80, and more preferably 0.70, 0.60, 0.50, 0.40, 0.35, 0.34, 0.33, and 0.32 in that order. The lower limit of the cation ratio is preferably 0.020, and more preferably 0.05, 0.09, 0.13, 0.15, 0.17, 0.19, 0.21, 0.22, 0.23, 0.24, and 0.25 in that order. From the viewpoint of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferable that the cation ratio be within the above range.

[0050] In the optical glass according to the first embodiment, Si 4+ , B 3+ , and P 5+ B relative to the total content of 3+ The content of cation ratio [B 3+ / (Si 4+ +B 3+ +P 5+The upper limit of the cation ratio is preferably 0.980, and more preferably 0.95, 0.91, 0.87, 0.85, 0.83, 0.81, 0.79, 0.78, 0.77, 0.76, and 0.75, in that order. The lower limit of the cation ratio is preferably 0.20, and more preferably 0.30, 0.40, 0.50, 0.60, 0.65, 0.66, 0.67, and 0.68, in that order. From the viewpoint of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferable that the cation ratio be within the above range.

[0051] In the optical glass according to the first embodiment, Si 4+ , B 3+ , and P 5+ P relative to the total content of 5+ The content of cation ratio [P 5+ / (Si 4+ +B 3+ +P 5+ The upper limit of the cation ratio is preferably 0.50, and more preferably 0.40, 0.30, 0.20, 0.10, 0.08, 0.06, 0.04, and 0.02 in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.005, 0.01, and 0.015 in that order. The cation ratio may be 0. From the viewpoint of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferable that the cation ratio be within the above range.

[0052] In the optical glass according to the first embodiment, Si 4+ , B 3+ , and P 5+ Si content relative to the total content 4+ and B 3+ The cation ratio of the total content [(Si 4+ +B 3+ ) / (Si 4+ +B 3+ +P 5+The lower limit of the cation ratio is preferably 0.2, and more preferably 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.85, 0.9, and 0.95 in that order. The upper limit of the cation ratio is preferably 1, and more preferably 0.99, 0.98, and 0.97 in that order. The cation ratio may be 1. From the viewpoint of obtaining an optical glass that is excellent in chemical durability and mechanical properties, it is preferable that the cation ratio be within the above range.

[0053] In the optical glass according to the first embodiment, Li + , Na + , and K. + Li relative to the total content of + The cation ratio of the content of [Li + / (Li + +Na + +K + The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, and 0.85 in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7 in that order. The cation ratio may be 1. From the viewpoint of suppressing a decrease in stability upon reheating and from the viewpoint of lowering the glass transition temperature Tg, it is preferable that the cation ratio be in the above range.

[0054] In the optical glass according to the first embodiment, Li + , Na + , and K. + Na relative to the total content of + The cation ratio of the content of [Na + / (Li + +Na + +K + The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, and 0.3 in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, and 0.15 in that order. The cation ratio may be 0. From the viewpoint of preventing a decrease in stability upon reheating and from the viewpoint of lowering the glass transition temperature Tg, it is preferable that the cation ratio be in the above range.

[0055] In the optical glass according to the first embodiment, Li + , Na + , and K. + K relative to the total content of + The content of cation ratio [K + / (Li + +Na + +K + The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, and 0.3 in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, and 0.15 in that order. The cation ratio may be 0. From the viewpoint of preventing a decrease in stability upon reheating and from the viewpoint of lowering the glass transition temperature Tg, it is preferable that the cation ratio be in the above range.

[0056] In the optical glass according to the first embodiment, Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ Mg content relative to the total content of 2+ The cation ratio of the content [Mg 2+ / (Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.55, and 0.5 in this order. The lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.18, 0.2, 0.22, 0.24, 0.26, 0.28, 0.30, 0.32, 0.34, 0.36, 0.38, 0.40, 0.42, 0.44, and 0.46 in this order. The cation ratio may be 0. From the viewpoint of preventing a decrease in the stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0057] In the optical glass according to the first embodiment, Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ Ca content relative to the total content2+ The cation ratio of the content of [Ca 2+ / (Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.15 in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 and 0.1 in that order. The cation ratio may be 0. From the viewpoint of preventing a decrease in the stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0058] In the optical glass according to the first embodiment, Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ Sr content relative to the total content 2+ The cation ratio of the content of [Sr 2+ / (Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.15 in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 and 0.1 in that order. The cation ratio may be 0. From the viewpoint of preventing a decrease in the stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0059] In the optical glass according to the first embodiment, Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ Ba relative to the total content 2+ The cation ratio of the content of [Ba 2+ / (Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+The lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, and 0.50, in that order. The upper limit of the cation ratio is preferably 1, and more preferably 0.90, 0.80, 0.75, 0.74, 0.73, 0.72, 0.71, 0.70, 0.69, 0.68, 0.67, 0.66, 0.65, 0.64, 0.63, 0.62, 0.61, 0.60, 0.59, 0.58, 0.57, 0.56, and 0.55, in that order. From the viewpoint of preventing a decrease in the stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0060] In the optical glass according to the first embodiment, Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and Zn 2+ Mg content relative to the total content of 2+ The cation ratio of the content [Mg 2+ / (Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.55, and 0.5 in this order. The lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.18, 0.2, 0.22, 0.24, 0.26, 0.28, 0.30, 0.32, 0.34, 0.36, 0.38, 0.40, 0.42, 0.44, and 0.46 in this order. The cation ratio may be 0. From the viewpoint of preventing a decrease in the stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0061] In the optical glass according to the first embodiment, Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and Zn 2+ Ca content relative to the total content 2+ The cation ratio of the content of [Ca 2+ / (Mg 2++Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.15 in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 and 0.1 in that order. The cation ratio may be 0. From the viewpoint of preventing a decrease in the stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0062] In the optical glass according to the first embodiment, Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and Zn 2+ Sr content relative to the total content 2+ The cation ratio of the content of [Sr 2+ / (Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.15 in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 and 0.1 in that order. The cation ratio may be 0. From the viewpoint of preventing a decrease in the stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0063] In the optical glass according to the first embodiment, Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and Zn 2+ Ba relative to the total content 2+ The cation ratio of the content of [Ba 2+ / (Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+The lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, and 0.50, in that order. The upper limit of the cation ratio is preferably 1, and more preferably 0.90, 0.80, 0.75, 0.74, 0.73, 0.72, 0.71, 0.70, 0.69, 0.68, 0.67, 0.66, 0.65, 0.64, 0.63, 0.62, 0.61, 0.60, 0.59, 0.58, 0.57, 0.56, and 0.55, in that order. From the viewpoint of preventing a decrease in the stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0064] In the optical glass according to the first embodiment, Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and Zn 2+ Zn content relative to the total 2+ The content of cation ratio [Zn 2+ / (Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, and 0.15 in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 and 0.1 in that order. The cation ratio may be 0. From the viewpoint of preventing a decrease in the stability and thermal stability of the glass during reheating, and from the viewpoint of maintaining the high refractive index of the glass, the cation ratio is preferably within the above range.

[0065] In the optical glass according to the first embodiment, La 3+ , Gd 3+ , and Y 3+ La relative to the total content 3+ The cation ratio of the content of [La 3+ / (La 3+ +Gd 3+ +Y 3+The lower limit of the cation ratio (n) is preferably 0, and more preferably 0.05, 0.10, 0.15, 0.20, 0.25, 0.27, 0.29, 0.31, 0.33, 0.35, 0.37, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, and 0.45, in that order. The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.60, 0.59, 0.58, 0.57, 0.56, 0.55, 0.54, and 0.53, in that order. From the viewpoints of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0066] In the optical glass according to the first embodiment, La 3+ , Gd 3+ , and Y 3+ Gd content relative to the total 3+ The cation ratio of the content of [Gd 3+ / (La 3+ +Gd 3+ +Y 3+ The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.60, 0.55, 0.50, 0.45, 0.40, 0.35, 0.30, 0.25, 0.20, 0.15, and 0.10 in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.01 and 0.05 in that order. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, the heavy rare earth element Gd 3+ From the viewpoint of reducing the content and suppressing an increase in raw material costs, it is preferable that the cation ratio be within the above range.

[0067] In the optical glass according to the first embodiment, La 3+ , Gd 3+ , and Y 3+ Y relative to the total content of 3+ The content of cation ratio [Y 3+ / (La 3+ +Gd 3+ +Y 3+The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.63, 0.61, 0.60, 0.59, 0.58, 0.57, 0.56, and 0.55, in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, 0.15, 0.20, 0.25, 0.27, 0.29, 0.31, 0.33, 0.35, 0.37, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, and 0.48, in that order. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0068] In the optical glass according to the first embodiment, Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ Ti content relative to the total content 4+ The cation ratio of the content of [Ti 4+ / (Ti 4+ +Nb 5+ +W 6+ +Bi 3+ The upper limit of the cation ratio (n) is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.23, 0.21, 0.2, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, and 0.11, in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, and 0.08, in that order. The cation ratio may be 0. From the viewpoints of increasing the refractive index nd and maintaining a desired Abbe number νd and thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0069] In the optical glass according to the first embodiment, Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ Nb content relative to the total content 5+ The cation ratio of the content of [Nb5+ / (Ti 4+ +Nb 5+ +W 6+ +Bi 3+ The upper limit of the cation ratio (n) is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.74, 0.73, 0.72, 0.71, 0.70, 0.69, 0.68, and 0.67, in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, and 0.62, in that order. The cation ratio may be 0. From the viewpoints of increasing the refractive index nd, maintaining a desired Abbe number νd, and maintaining the thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0070] In the optical glass according to the first embodiment, Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ W relative to the total content of 6+ The content of cation ratio [W 6+ / (Ti 4+ +Nb 5+ +W 6+ +Bi 3+ The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.45, 0.44, 0.43, 0.42, 0.41, 0.40, 0.39, 0.38, 0.37, 0.36, 0.35, 0.34, 0.33, 0.32, 0.31, 0.3, 0.29, 0.28, and 0.27, in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, 0.12, 0.14, 0.16, 0.18, 0.20, 0.21, 0.22, 0.23, and 0.24, in that order. The cation ratio may be 0. From the viewpoints of increasing the partial dispersion ratio Pg,F, maintaining a desired Abbe number vd, and maintaining the thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0071] In the optical glass according to the first embodiment, Ti4+ , Nb 5+ , W 6+ , and Bi 3+ Bi relative to the total content 3+ The cation ratio of the content of [Bi 3+ / (Ti 4+ +Nb 5+ +W 6+ +Bi 3+ The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.45, 0.44, 0.43, 0.42, 0.41, 0.40, 0.39, 0.38, 0.37, 0.36, 0.35, 0.34, 0.33, 0.32, 0.31, 0.3, 0.29, 0.28, and 0.27, in that order. The lower limit of the cation ratio is preferably 0, and may be 0.05, 0.1, 0.12, 0.14, 0.16, 0.18, 0.20, 0.21, 0.22, 0.23, or 0.24. The cation ratio may be 0. It is preferable to set the cation ratio within the above range from the viewpoints of increasing the refractive index nd and the partial dispersion ratio Pg,F, maintaining a desired Abbe number νd, maintaining the thermal stability of the glass, and reducing damage to platinum production melting equipment.

[0072] In the optical glass according to the first embodiment, Zr 4+ and Ta 5+ Zr content relative to the total 4+ The cation ratio of the content of [Zr 4+ / (Zr 4+ +Ta 5+ The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, and 0.85 in that order. The lower limit of the cation ratio is preferably 0, and may be 0.5, 0.6, 0.7, or 0.8. The cation ratio may be 0. From the viewpoints of maintaining desired optical constants and reducing raw material costs, it is preferable that the cation ratio be within the above range.

[0073] In the optical glass according to the first embodiment, Zr 4+ and Ta 5+ Ta relative to the total content 5+ The cation ratio of the content [Ta 5+ / (Zr 4+ +Ta 5+ The upper limit of the cation ratio is preferably 1, and more preferably 0.5, 0.4, 0.3, and 0.2 in that order. The lower limit of the cation ratio is preferably 0, and may be 0.05, 0.10, or 0.15. The cation ratio may be 0. From the viewpoints of maintaining desired optical constants and reducing raw material costs, it is preferable that the cation ratio be within the above range.

[0074] In the optical glass according to the first embodiment, Ti 4+ , Nb 5+ , Bi 3+ , W 6+ , Zr 4+ , and Ta 5+ Ti content relative to the total content 4+ The cation ratio of the content of [Ti 4+ / (Ti 4+ +Nb 5+ +Bi 3+ +W 6+ +Zr 4+ +Ta 5+ The upper limit of the cation ratio (n) is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.23, 0.21, 0.2, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11, 0.10, 0.09, 0.08, 0.07, and 0.06, in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, and 0.04, in that order. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd and maintaining a desired Abbe number νd, it is preferable that the cation ratio be within the above range.

[0075] In the optical glass according to the first embodiment, Ti 4+ , Nb 5+ , Bi 3+ , W 6+ , Zr 4+ , and Ta 5+ Nb content relative to the total content 5+ The cation ratio of the content of [Nb 5+ / (Ti 4+ +Nb5+ +Bi 3+ +W 6+ +Zr 4+ +Ta 5+ The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.60, 0.55, 0.50, 0.45, 0.40, 0.35, 0.34, 0.33, 0.32, 0.31, 0.30, 0.29, 0.28, and 0.27, in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, and 0.24, in that order. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd and maintaining a desired Abbe number vd, it is preferable that the cation ratio be within the above range.

[0076] In the optical glass according to the first embodiment, Ti 4+ , Nb 5+ , Bi 3+ , W 6+ , Zr 4+ , and Ta 5+ Bi relative to the total content 3+ The cation ratio of the content of [Bi 3+ / (Ti 4+ +Nb 5+ +Bi 3+ +W 6+ +Zr 4+ +Ta 5+The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.35, 0.30, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, 0.20, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, and 0.11, in that order. The lower limit of the cation ratio is preferably 0, and may be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, or 0.09. The cation ratio may be 0. It is preferable to set the cation ratio within the above range from the viewpoints of increasing the refractive index nd and the partial dispersion ratio Pg,F, maintaining a desired Abbe number νd, maintaining the thermal stability of the glass, and reducing damage to platinum production melting equipment.

[0077] In the optical glass according to the first embodiment, Ti 4+ , Nb 5+ , Bi 3+ , W 6+ , Zr 4+ , and Ta 5+ W relative to the total content of 6+ The content of cation ratio [W 6+ / (Ti 4+ +Nb 5+ +Bi 3+ +W 6+ +Zr 4+ +Ta 5+ The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.35, 0.30, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, 0.20, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, and 0.11, in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, and 0.09, in that order. The cation ratio may be 0. From the viewpoints of increasing the partial dispersion ratio Pg,F, maintaining a desired Abbe number vd, and maintaining the thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0078] In the optical glass according to the first embodiment, Ti 4+ , Nb 5+ , Bi 3+ , W 6+ , Zr 4+ , and Ta 5+ Zr content relative to the total 4+ The cation ratio of the content of [Zr 4+ / (Ti 4+ +Nb 5+ +Bi 3+ +W 6+ +Zr 4+ +Ta 5+ The upper limit of the cation ratio (νd) is preferably 1, and more preferably 0.95, 0.9, 0.85, 0.80, 0.75, 0.70, 0.69, 0.68, 0.67, 0.66, 0.65, 0.64, 0.63, and 0.62, in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.1, 0.2, 0.3, 0.4, 0.45, 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, and 0.58, in that order. The cation ratio may be 0. From the viewpoints of increasing the refractive index nd, maintaining a desired Abbe number νd, and improving the mechanical properties and chemical durability of the glass, it is preferable that the cation ratio be within the above range.

[0079] In the optical glass according to the first embodiment, Ti 4+ , Nb 5+ , Bi 3+ , W 6+ , Zr 4+ , and Ta 5+ Ta relative to the total content 5+ The cation ratio of the content [Ta 5+ / (Ti 4+ +Nb 5+ +Bi 3+ +W 6+ +Zr 4+ +Ta 5+The upper limit of the cation ratio is preferably 1, and more preferably 0.5, 0.4, 0.3, 0.25, 0.2, 0.15, 0.1, 0.08, 0.06, and 0.04 in that order. The lower limit of the cation ratio is preferably 0, and may be 0.01, 0.02, or 0.03. The cation ratio may be 0. From the viewpoints of maintaining desired constants and reducing raw material costs, it is preferable that the cation ratio be within the above range.

[0080] In the optical glass according to the first embodiment, Si 4+ and B 3+ Al content relative to the total content 3+ The cation ratio of the content of [Al 3+ / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 0.5, and more preferably 0.45, 0.40, 0.35, 0.30, 0.25, and 0.20 in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.05, 0.1, and 0.15 in that order. The cation ratio may be 0. Increasing the cation ratio can improve the mechanical properties and chemical durability of the glass. On the other hand, if the cation ratio is too high, the liquidus temperature rises and the thermal stability of the glass is impaired. From the viewpoint of maintaining the thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0081] In the optical glass according to the first embodiment, Li + , Na + , and K. + Al content relative to the total content 3+ The cation ratio of the content of [Al 3+ / (Li + +Na + +K +The upper limit of the cation ratio is preferably 2, and more preferably 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, and 0.2 in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15 in that order. The cation ratio may be 0. Increasing the cation ratio can improve the mechanical properties and chemical durability of the glass. On the other hand, if the cation ratio is too high, the liquidus temperature rises and the thermal stability of the glass is impaired. From the viewpoint of maintaining the thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0082] In the optical glass according to the first embodiment, Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ Al content relative to the total content 3+ The cation ratio of the content of [Al 3+ / (Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The upper limit of the cation ratio is preferably 2, and more preferably 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, 0.3, and 0.2 in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15 in that order. The cation ratio may be 0. Increasing the cation ratio can improve the mechanical properties and chemical durability of the glass. On the other hand, if the cation ratio is too high, the liquidus temperature rises and the thermal stability of the glass is impaired. From the viewpoint of maintaining the thermal stability and devitrification resistance of the glass, it is preferable that the cation ratio be within the above range.

[0083] In the optical glass according to the first embodiment, Li + , Na + , K. + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ Al content relative to the total content 3+ The cation ratio of the content of [Al 3+ / (Li+ +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The upper limit of the cation ratio is preferably 5, and more preferably 4, 3, 2, 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, 0.3, and 0.2, in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15, in that order. The cation ratio may be 0. Increasing the cation ratio can improve the mechanical properties and chemical durability of the glass. On the other hand, if the cation ratio is too high, the liquidus temperature rises, and the thermal stability of the glass is impaired. From the viewpoint of maintaining the thermal stability and devitrification resistance of the glass, it is preferable that the cation ratio be within the above range.

[0084] In the optical glass according to the first embodiment, La 3+ , Gd 3+ , and Y 3+ Al content relative to the total content 3+ The cation ratio of the content of [Al 3+ / (La 3+ +Gd 3+ +Y 3+ The upper limit of the cation ratio is preferably 2, and more preferably 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, 0.3, and 0.2 in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15 in that order. The cation ratio may be 0. From the viewpoints of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0085] In the optical glass according to the first embodiment, Si 4+ and B 3+ Li relative to the total content of + , Na + , and K. + The cation ratio of the total content [(Li + +Na + +K + ) / (Si4+ +B 3+ The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.75, 0.70, 0.65, 0.60, 0.55, 0.50, 0.45, 0.43, 0.42, 0.41, and 0.40, in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.32, 0.33, 0.34, and 0.35, in that order. From the viewpoints of improving the chemical durability, mechanical properties, and thermal stability of the glass and suppressing a decrease in stability upon reheating, and from the viewpoint of obtaining an optical glass with a reduced glass transition temperature Tg, it is preferable that the cation ratio be within the above range.

[0086] In the optical glass according to the first embodiment, Si 4+ and B 3+ Mg content relative to the total content of 2+ , Ca 2+ , Sr 2+ , and Ba 2+ The cation ratio of the total content [(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ) / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.68, 0.66, 0.64, 0.62, 0.60, 0.59, and 0.58, in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.17, 0.19, 0.21, 0.23, 0.25, 0.27, 0.29, 0.31, 0.33, 0.35, 0.37, 0.39, 0.41, 0.43, 0.45, 0.47, 0.49, 0.51, 0.53, and 0.55, in that order. From the viewpoint of preventing deterioration of the chemical durability, mechanical properties, and thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0087] In the optical glass according to the first embodiment, Si 4+ and B 3+ Li relative to the total content of + , Na+ , K. + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ The cation ratio of the total content [(Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ) / (Si 4+ +B 3+ The lower limit of the cation ratio is preferably 0.01, and more preferably 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, and 0.95, in that order. The upper limit of the cation ratio is preferably 2, and more preferably 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, and 1.0, in that order. From the viewpoint of obtaining an optical glass having desired optical constants, suppressing volatilization of glass components during melting, and reducing the glass transition temperature Tg, it is preferable that the cation ratio be within the above range.

[0088] In the optical glass according to the first embodiment, Si 4+ and B 3+ La relative to the total content 3+ , Gd 3+ , and Y 3+ The cation ratio of the total content [(La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+The lower limit of the cation ratio is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 1.02, 1.04, 1.06, 1.08, 1.10, 1.12, 1.14, 1.16, 1.18, 1.20, 1.21, 1.22, 1.23, 1.24, and 1.25, in that order. The upper limit of the cation ratio is preferably 3, and more preferably 2.5, 2, 1.9, 1.8, 1.75, 1.70, 1.65, 1.60, 1.55, 1.50, 1.45, 1.40, 1.38, 1.36, 1.34, 1.32, and 1.30, in that order. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0089] In the optical glass according to the first embodiment, Si 4+ and B 3+ Li relative to the total content of + , Na + , K. + , Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , La 3+ , Gd 3+ , and Y 3+ The cation ratio of the total content [(Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+), the lower limit of which is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, 1.90, 1.95, 2.00, 2.05, 2.10, 2.15, and 2.20 in that order. The upper limit of the cation ratio is preferably 4, and more preferably 3.5, 3.0, 2.8, 2.6, 2.5, 2.4, 2.37, 2.35, 2.33, 2.31, 2.29, 2.27, and 2.25, in that order. From the viewpoint of obtaining an optical glass that is excellent in chemical durability, mechanical properties, and thermal stability while suppressing volatilization of glass components during melting, it is preferable that the cation ratio be within the above range.

[0090] In the optical glass according to the first embodiment, Si 4+ and B 3+ Ti content relative to the total content 4+ , Nb 5+ , W 6+ , and Bi 3+ The cation ratio of the total content [(Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ) / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 0.5, and more preferably 0.4, 0.3, 0.2, and 0.1 in this order. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, and 0.04 in this order. The cation ratio may be 0. From the viewpoint of suppressing a decrease in the refractive index nd at a desired Abbe number νd, it is preferable that the cation ratio be within the above range.

[0091] In the optical glass according to the first embodiment, Si 4+ and B 3+ Zr content relative to the total 4+ and Ta 5+ The cation ratio of the total content [(Zr 4+ +Ta 5+) / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 0.5, and more preferably 0.4, 0.3, 0.2, and 0.1 in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, and 0.04 in that order. The cation ratio may be 0. From the viewpoint of maintaining the thermal stability of the glass and from the viewpoint of suppressing a decrease in the refractive index nd at a desired Abbe number νd, it is preferable that the cation ratio be within the above range.

[0092] In the optical glass according to the first embodiment, Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ Li relative to the total content of + , Na + , and K. + The cation ratio of the total content [(Li + +Na + +K + ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.56, 0.54, 0.52, 0.50, 0.48, 0.46, 0.44, 0.42, and 0.40, in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.07, 0.09, 0.11, 0.13, 0.15, 0.17, 0.19, 0.21, 0.23, 0.25, 0.27, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, and 0.37, in that order. The cation ratio may be 0. From the viewpoint of improving the chemical durability, mechanical properties, and thermal stability of the glass and suppressing a decrease in stability upon reheating, and from the viewpoint of obtaining an optical glass with a reduced glass transition temperature Tg, it is preferable that the cation ratio be within the above range.

[0093] In the optical glass according to the first embodiment, Si4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ Mg relative to the total content of 2+ , Ca 2+ , Sr 2+ , and Ba 2+ The cation ratio of the total content [(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.63, 0.61, 0.60, and 0.59, in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.17, 0.19, 0.21, 0.23, 0.25, 0.27, 0.29, 0.31, 0.33, 0.35, 0.37, 0.39, 0.41, 0.43, 0.45, 0.47, 0.49, 0.51, 0.53, and 0.55, in that order. From the viewpoint of preventing deterioration of the chemical durability, mechanical properties, and thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0094] In the optical glass according to the first embodiment, Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ Li relative to the total content of + , Na + , K. + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ The cation ratio of the total content [(Li + +Na + +K + +Mg 2+ +Ca 2++Sr 2+ +Ba 2+ ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ The lower limit of the cation ratio is preferably 0.01, and more preferably 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.91, 0.92, 0.93, and 0.94, in that order. The upper limit of the cation ratio is preferably 3, and more preferably 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, and 1.05, in that order. From the viewpoint of obtaining an optical glass having desired optical constants, suppressing volatilization of glass components during melting, and lowering the glass transition temperature Tg, it is preferable that the cation ratio be within the above range.

[0095] In the optical glass according to the first embodiment, Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ La relative to the total content 3+ , Gd 3+ , and Y 3+ The cation ratio of the total content [(La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+The lower limit of )] is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.07, 1.09, 1.11, 1.13, 1.15, 1.17, 1.19, 1.20, 1.21, 1.22, 1.23, 1.24, and 1.25 in that order. The upper limit of the cation ratio is preferably 3, and more preferably 2.5, 2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.45, 1.40, 1.35, 1.34, 1.33, 1.32, 1.31, 1.30, 1.29, and 1.28, in that order. From the viewpoints of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0096] In the optical glass according to the first embodiment, Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ Li relative to the total content of + , Na + , K. + , Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , La 3+ , Gd 3+ , and Y 3+ The cation ratio of the total content [(Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+), the lower limit of which is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, 1.90, 1.95, 2.00, 2.05, 2.10, 2.15, and 2.20 in that order. The upper limit of the cation ratio is preferably 4, and more preferably 3.8, 3.6, 3.4, 3.2, 3.0, 2.9, 2.8, 2.7, 2.65, 2.60, 2.55, 2.50, 2.40, 2.35, 2.30, and 2.25, in that order. From the viewpoint of obtaining an optical glass that is excellent in chemical durability, mechanical properties, and thermal stability while suppressing volatilization of glass components during melting, it is preferable to set the cation ratio within the above range.

[0097] In the optical glass according to the first embodiment, Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ and Ta 5+ Li relative to the total content of + , Na + , and K. + The cation ratio of the total content [(Li + +Na + +K + ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.56, 0.54, 0.52, 0.50, 0.48, 0.46, 0.44, 0.42, and 0.40, in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.07, 0.09, 0.11, 0.13, 0.15, 0.17, 0.19, 0.21, 0.23, 0.25, 0.27, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, and 0.37, in that order. From the viewpoints of improving the chemical durability, mechanical properties, and thermal stability of the glass and suppressing a decrease in stability upon reheating, and from the viewpoint of obtaining an optical glass with a reduced glass transition temperature Tg, it is preferable that the cation ratio be within the above range.

[0098] In the optical glass according to the first embodiment, Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ and Ta 5+ Mg relative to the total content of 2+ , Ca 2+ , Sr 2+ , and Ba 2+ The cation ratio of the total content [(Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.63, 0.61, 0.60, and 0.59, in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.17, 0.19, 0.21, 0.23, 0.25, 0.27, 0.29, 0.31, 0.33, 0.35, 0.37, 0.39, 0.41, 0.43, 0.45, 0.47, 0.49, 0.51, 0.53, and 0.55, in that order. From the viewpoint of preventing deterioration of the chemical durability, mechanical properties, and thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0099] In the optical glass according to the first embodiment, Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ and Ta 5+ Li relative to the total content of + , Na + , K. + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ The cation ratio of the total content [(Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+The lower limit of the cation ratio is preferably 0.01, and more preferably 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.91, 0.92, 0.93, and 0.94, in that order. The upper limit of the cation ratio is preferably 3, and more preferably 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, and 1.05, in that order. From the viewpoint of obtaining an optical glass having desired optical constants, suppressing volatilization of glass components during melting, and lowering the glass transition temperature Tg, it is preferable that the cation ratio be within the above range.

[0100] In the optical glass according to the first embodiment, Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ and Ta 5+ La relative to the total content 3+ , Gd 3+ , and Y 3+ The cation ratio of the total content [(La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+The lower limit of )] is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.07, 1.09, 1.11, 1.13, 1.15, 1.17, 1.19, 1.20, 1.21, 1.22, 1.23, 1.24, and 1.25 in that order. The upper limit of the cation ratio is preferably 3, and more preferably 2.5, 2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.45, 1.40, 1.35, 1.34, 1.33, 1.32, 1.31, 1.30, 1.29, and 1.28, in that order. From the viewpoints of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0101] In the optical glass according to the first embodiment, Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ and Ta 5+ Li relative to the total content of + , Na + , K. + , Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , La 3+ , Gd 3+ , and Y 3+ The cation ratio of the total content [(Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+), the lower limit of which is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, 1.90, 1.95, 2.00, 2.05, 2.10, 2.15, and 2.20 in that order. The upper limit of the cation ratio is preferably 4, and more preferably 3.8, 3.6, 3.4, 3.2, 3.0, 2.9, 2.8, 2.7, 2.65, 2.60, 2.55, 2.50, 2.40, 2.35, 2.30, and 2.25, in that order. From the viewpoint of obtaining an optical glass that is excellent in chemical durability, mechanical properties, and thermal stability while suppressing volatilization of glass components during melting, it is preferable to set the cation ratio within the above range.

[0102] In the optical glass according to the first embodiment, Si 4+ , B 3+ , P 5+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ , and Ta 5+ La relative to the total content 3+ , Gd 3+ , Y 3+ , Li + , Na + , K. + , Rb + , Cs + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ The cation ratio of the total content [(La 3+ +Gd 3+ +Y 3+ +Li + +Na + +K + +Rb + +Cs + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ) / (Si4+ +B 3+ +P 5+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+ The lower limit of )] is preferably 0.50, and more preferably 0.60, 0.70, 0.80, 0.90, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, 1.90, 1.95, 2.00, 2.05, 2.10, 2.15, and 2.20 in that order. The upper limit of the cation ratio is preferably 4, and more preferably 3.8, 3.6, 3.4, 3.2, 3.0, 2.9, 2.8, 2.7, 2.65, 2.60, 2.55, 2.50, 2.40, 2.35, 2.30, and 2.25, in that order. If the cation ratio is too small, volatilization of glass components may increase. If the cation ratio is too large, the thermal stability of the glass may decrease. From the viewpoint of suppressing volatilization of glass components, it is preferable that the cation ratio be within the above range.

[0103] In the optical glass according to the first embodiment, P 5+ The upper limit of the content of P is preferably 30%, and more preferably 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, and 1% in that order. 5+ The lower limit of the content of P is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5% in that order. 5+ The content of P may be 0%. 5+ By setting the content within the above range, it is possible to obtain glass having relatively high mechanical properties and chemical durability.

[0104] In the optical glass according to the first embodiment, Al 3+ The upper limit of the content of Al is preferably 30%, and more preferably 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, and 1% in that order. 3+The lower limit of the Al content is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5% in that order. 3+ The content of Al may be 0%. 3+ When contained in an appropriate amount, Al has the effect of suppressing phase separation of glass. 3+ Increasing the content of Al can improve the mechanical properties and chemical durability of the glass. 3+ If the content of Al becomes too high, the liquidus temperature rises and the thermal stability of the glass is impaired. When the liquidus temperature rises, the volatilization of glass components increases during the flow and molding of the glass, causing striae. From the viewpoint of maintaining the thermal stability of the glass, Al 3+ It is preferable that the content of is within the above range.

[0105] In the glass according to the first embodiment, Li + The upper limit of the content of Li is preferably 40%, and more preferably 30%, 20%, 17%, 15%, 14%, 13%, and 12.5% ​​in that order. + The lower limit of the content of Li is preferably 0%, and more preferably 1%, 2%, 3%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, and 11.5% in that order. + The content of Li may be 0%. + Li is a component that contributes to lowering the viscosity of the glass. + If the content of Li is too high, the thermal stability of the glass and its stability during reheating may decrease. + If the content of Li is too low, the glass transition temperature Tg may increase. + The content is preferably in the above range.

[0106] In the glass according to the first embodiment, Na + The upper limit of the content of is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5% in that order. +The lower limit of the Na content is preferably 0%, and more preferably 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, and 0.35%, in that order. + The content of Na may be 0%. + Li + Like Na, it is a component that contributes to lowering the viscosity of glass. + If the content of Na is too high, the thermal stability of the glass and its stability during reheating may decrease. + The content is preferably in the above range.

[0107] In the optical glass according to the first embodiment, K + The upper limit of the content of is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5% in that order. + The lower limit of the content of K is preferably 0%, and more preferably 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, and 0.35% in that order. + The content of K may be 0%. + has the function of lowering the liquidus temperature and improving the thermal stability of the glass. + If the content of K is too high, chemical durability, weather resistance, and stability during reheating will decrease. + The content is preferably in the above range.

[0108] In the optical glass according to the first embodiment, Rb + The upper limit of the content of Rb is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5% in that order. + The lower limit of the content of Rb is preferably 0%. + The content of Rb may be 0%. + If the content of Rb is too high, the volatilization of glass components during melting increases, making it impossible to obtain the desired glass. + The content is preferably in the above range.

[0109] In the optical glass according to the first embodiment, Cs + The upper limit of the content of Cs is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5% in that order. + The lower limit of the content of Cs is preferably 0%. + The content of Cs may be 0%. + If the content of Cs is too high, the volatilization of glass components during melting increases, making it impossible to obtain the desired glass. In addition, there is a risk that the chemical durability and weather resistance will decrease. + The content is preferably in the above range.

[0110] In the optical glass according to the first embodiment, Mg 2+ The upper limit of the content of Mg is preferably 40%, and more preferably 30%, 20%, 18%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, and 9% in that order. 2+ The lower limit of the Mg content is preferably 0%, and more preferably 1%, 2%, 3%, 4%, 5%, 6%, 7%, and 8% in that order. 2+ The content of Mg may be 0%. 2+ If the content of Mg is too high, the thermal stability and devitrification resistance of the glass may decrease. 2+ If the content is too low, the stability of the glass may decrease when reheated. 2+ The content is preferably in the above range.

[0111] In the optical glass according to the first embodiment, Ca 2+ The upper limit of the content of Ca is preferably 25%, and more preferably 20%, 15%, 10%, 9%, 8%, 7%, 6%, and 5% in that order. 2+ The lower limit of the Ca content is preferably 0%, and more preferably 0.5%, 1%, and 2% in that order. 2+ The content of Ca may be 0%. 2+If the content of Ca is too high, the thermal stability of the glass may be impaired, and the glass transition temperature Tg and liquidus temperature TL may increase. 2+ It is preferable that the content of is within the above range.

[0112] In the optical glass according to the first embodiment, Sr 2+ The upper limit of the Sr content is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5% in that order. 2+ The lower limit of the Sr content is preferably 0%. 2+ The content of Sr may be 0%. 2+ is a component that increases the refractive index nd among alkaline earth metals. 2+ If the content of Sr is too high, the thermal stability and devitrification resistance of the glass may be reduced. 2+ The content is preferably in the above range.

[0113] In the optical glass according to the first embodiment, Ba 2+ The upper limit of the Ba content is preferably 40%, and more preferably 30%, 25%, 20%, 18%, 16%, 15%, 14%, 13%, 12%, 11%, and 10%, in that order. 2+ The lower limit of the Ba content is preferably 0%, and more preferably 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, and 9% in that order. 2+ Among alkaline earth metals, Ba is a component that increases the refractive index nd, and at the same time, when contained in an appropriate amount, it lowers the liquidus temperature and improves the stability of the glass. 2+ If the content of Ba is too high, the thermal stability and stability during reheating of the glass may be reduced. 2+ If the content of Ba is too low, the thermal stability of the glass may decrease and the volatilization of glass components during melting may increase. 2+ The content is preferably in the above range.

[0114] In the optical glass according to the first embodiment, Zn 2+ The upper limit of the content of Zn is preferably 13%, and more preferably 10%, 8%, 6%, and 5% in that order. 2+ The lower limit of the content of Zn is preferably 0%, and more preferably 0.5%, 1%, and 2% in that order. 2+ The content may be 0%.

[0115] Zn 2+ is a glass component that acts to lower the glass transition temperature Tg. 2+ If the content of Zn is too high, the specific gravity may increase, the thermal stability and chemical durability of the glass may decrease, and the Abbe number may increase, making it difficult to obtain the desired high refractive index characteristics. Therefore, from the viewpoint of obtaining an optical glass with an improved glass transition temperature Tg, it is recommended to use a Zn content of 100%. 2+ It is preferable that the content of is within the above range.

[0116] In the optical glass according to the first embodiment, La 3+ The lower limit of the content of La is preferably 5%, and more preferably 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 14.5%, 15%, 15.5%, 16%, 16.5%, 17%, and 17.5% in that order. 3+ The upper limit of the content of La is preferably 50%, and more preferably 48%, 46%, 44%, 42%, 40%, 38%, 36%, 34%, 32%, 30%, 28%, 26%, 24%, 23%, 22%, 21.5%, 21%, 20.5%, and 20%, in that order. 3+ By introducing a certain amount of La, it is possible to suppress the volatilization of glass components and increase the refractive index nd. 3+ If the content of La is too high, the thermal stability of the glass may decrease, and the glass may be prone to devitrification during manufacturing. 3+ The content is preferably in the above range.

[0117] In the glass according to the first embodiment, Gd 3+The upper limit of the content of Gd is preferably 50%, and more preferably 40%, 30%, 20%, 15%, 10%, 8%, 6%, 4%, 3%, 2%, and 1% in that order. 3+ The lower limit of the content of Gd is preferably 0%. 3+ The content of Gd may be 0%. 3+ La 3+ Similarly, by introducing a certain amount of Gd, it is possible to suppress the volatilization of glass components and increase the refractive index nd. 3+ If the content is too high, the thermal stability of the glass will decrease. 3+ If the content of Gd is too high, the specific gravity of the glass increases, which is undesirable. In addition, there is a risk of increasing the raw material cost. Therefore, from the viewpoint of suppressing the increase in specific gravity while maintaining good thermal stability of the glass, and from the viewpoint of suppressing the increase in specific gravity, and from the viewpoint of suppressing the increase in the content of Gd, which is a heavy rare earth, it is preferable to use a glass containing Gd as the glass having a high thermal stability. 3+ From the viewpoint of reducing the content of Gd 3+ The content is preferably in the above range.

[0118] In the glass according to the first embodiment, Y 3+ The upper limit of the content of is preferably 50%, and more preferably 48%, 46%, 44%, 42%, 40%, 38%, 36%, 34%, 32%, 30%, 28%, 26%, 25%, 24%, 23%, 22.5%, 22%, and 21.5% in that order. 3+ The lower limit of the content of Y is preferably 0%, and more preferably 1%, 5%, 8%, 10%, 12%, 14%, 16%, and 18% in that order. 3+ The content may be 0%.

[0119] Y 3+ By introducing a certain amount of Y, it is possible to suppress the volatilization of glass components and increase the refractive index nd. 3+ If the content of Y is too high, the thermal stability of the glass decreases and the glass becomes more susceptible to devitrification during manufacturing. 3+ If the content of Y is too small, the thermal stability of the glass may be reduced. 3+ The content is preferably in the above range.

[0120] In the glass according to the first embodiment, Yb 3+ The upper limit of the content of Yb is preferably 50%, and more preferably 40%, 30%, 20%, 15%, 10%, 8%, 6%, 4%, 3%, 2%, and 1% in that order. 3+ The lower limit of the content of Yb is preferably 0%. 3+ The content of Yb may be 0%. 3+ La 3+ , Gd 3+ , Y 3+ Its molecular weight is larger than that of Yb, which increases the specific gravity of the glass. 3+ If the content of Yb is too high, the thermal stability of the glass will decrease. 3+ The content is preferably in the above range.

[0121] In the optical glass according to the first embodiment, Ti 4+ The upper limit of the Ti content is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5% in that order. 4+ The lower limit of the Ti content is preferably 0%, and may also be 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, or 1.6%. 4+ The content of Ti may be 0%. From the viewpoint of maintaining a desired Abbe number νd and improving anomalous partial dispersion in the visible to near ultraviolet region, 4+ It is preferable that the content of is within the above range.

[0122] In the optical glass according to the first embodiment, Nb 5+ The upper limit of the Nb content is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5% in that order. 5+ The lower limit of the Nb content is preferably 0%, and more preferably 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, and 1.6% in that order. 5+The content of Nb may be 0%. From the viewpoint of maintaining a desired Abbe number νd and improving anomalous partial dispersion in the visible to near ultraviolet region, 5+ It is preferable that the content of is within the above range.

[0123] In the optical glass according to the first embodiment, W 6+ The upper limit of the content of W is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5% in that order. 6+ The lower limit of the content of W is preferably 0%, and more preferably 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, and 1.6%, in that order. 6+ The content of W may be 0%. From the viewpoint of increasing the transmittance and reducing the specific gravity, maintaining the desired Abbe number νd, and improving the anomalous partial dispersion in the visible to near ultraviolet region, 6+ It is preferable that the content of is within the above range.

[0124] In the optical glass according to the first embodiment, Bi 3+ The upper limit of the content of Bi is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5% in that order. 3+ The lower limit of the content of Bi is preferably 0%, and may also be 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, or 1.6%. 3+ The content of Bi may be 0%. From the viewpoints of increasing the transmittance and reducing the specific gravity, reducing damage to platinum manufacturing equipment, and improving the anomalous partial dispersion in the visible to near ultraviolet region, Bi is used. 3+ It is preferable that the content of is within the above range.

[0125] In the optical glass according to the first embodiment, Zr 4+ The upper limit of the content of Zr is preferably 10%, and more preferably 8%, 6%, 4%, 3%, 2%, and 1% in that order. 4+The lower limit of the Zr content is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5% in that order. 4+ The content of Zr may be 0%. 4+ The appropriate amount of Zr has the effect of improving chemical durability. 4+ If the content of Zr is too high, the liquidus temperature LT may increase and the melting property of the glass may decrease. 4+ It is preferable that the content of is within the above range.

[0126] In the optical glass according to the first embodiment, Ta 5+ The upper limit of the content of Ta is preferably 10%, and more preferably 8%, 6%, 4%, 3%, 2%, and 1% in that order. 5+ The lower limit of the Ta content is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5% in that order. 5+ The content of Ta may be 0%. 5+ is a component that contributes to the high refractive index and low dispersion of the glass. 5+ If the content of Ta is too high, the raw material cost may increase, and the melting property of the glass may decrease. Furthermore, the specific gravity may increase. 5+ The content is preferably in the above range.

[0127] In the optical glass according to the first embodiment, Ge 4+ The upper limit of the content of Ge is preferably 5%, and more preferably 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, and 0.5% in that order. 4+ The lower limit of the Ge content is preferably 0%. 4+ The content may be 0%.

[0128] Ge 4+ Although Ge has the function of enhancing the high dispersibility of glass, it is an extremely expensive component among commonly used glass components. Therefore, from the viewpoint of reducing the manufacturing cost of glass, Ge 4+ It is preferable that the content of is within the above range.

[0129] In the glass according to the first embodiment, Sc 3+ The content of Sc is preferably 2% or less. 3+ The lower limit of the content is preferably 0%.

[0130] In the glass according to the first embodiment, Hf 4+ The content of Hf is preferably 2% or less. 4+ The lower limit of the content is preferably 0%.

[0131] Sc 3+ , Hf 4+ Although Sc has the effect of increasing the dispersibility of the glass, it is an expensive component. 3+ , Hf 4+ The content of each of the above is preferably within the above range.

[0132] In the glass according to the first embodiment, Lu 3+ The content of Lu is preferably 2% or less. 3+ The lower limit of the content is preferably 0%.

[0133] Lu 3+ Although Lu has the function of increasing the dispersibility of glass, it is also a glass component that increases the specific gravity of glass due to its large molecular weight. 3+ The content is preferably in the above range.

[0134] The glass according to the first embodiment contains Si as an essential component. 4+ and B 3+ , optionally containing Ca 2+ , Zn 2+ , P 5+ , Al 3+ , Li + , Na + , K. + , Rb + , Cs + , Mg 2+ , Sr 2+ , Ba 2+ , La 3+ , Gd3+ , Y 3+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Ta 5+ , and Zr 4+ The total content of these glass components is preferably 95% or more, more preferably 98% or more, even more preferably 99% or more, and particularly preferably 99.5% or more.

[0135] The optical glass according to the first embodiment contains O as an anion component. 2- Includes: O 2- The upper limit of the content of is preferably 90 anion%, and more preferably 80 anion%, 75 anion%, 73 anion%, 71 anion%, 69 anion%, 67 anion%, 65 anion%, 63 anion%, 61 anion%, 60 anion%, 59 anion%, 58 anion%, 57 anion%, 56 anion%, 55 anion%, 54 anion%, 53 anion%, 52 anion%, 51 anion%, 50 anion%, 49 anion%, 48 anion%, 47 anion%, 46 anion%, 45 anion%, 44 anion%, and 43 anion% in that order. 2- The lower limit of the content is preferably 10 anion%, and more preferably 12 anion%, 14 anion%, 16 anion%, 18 anion%, 20 anion%, 22 anion%, 24 anion%, 26 anion%, 28 anion%, 30 anion%, 32 anion%, 34 anion%, 35 anion%, 36 anion%, 37 anion%, 38 anion%, 39 anion%, 40 anion%, and 41 anion%, in that order.

[0136] The optical glass according to the first embodiment contains O as an anion component. 2- and F - It may contain ingredients other than those listed above. 2- and F - Other anion components include Cl - , Br - , I - However, Cl- , Br - , I - All of these components are prone to volatilization during glass melting. The volatilization of these components causes problems such as fluctuations in the glass properties, a decrease in the homogeneity of the glass, and significant wear on the melting equipment. - The content of Br is preferably less than 5 anion %, more preferably less than 3 anion %, even more preferably less than 1 anion %, particularly preferably less than 0.5 anion %, and even more preferably less than 0.25 anion %. - and I - The total content is preferably less than 5 anion %, more preferably less than 3 anion %, even more preferably less than 1 anion %, particularly preferably less than 0.5 anion %, even more preferably less than 0.1 anion %, and even more preferably 0 anion %.

[0137] The glass according to the first embodiment is preferably composed essentially of the above glass components, but may contain other components as long as they do not impair the effects of the present invention. Furthermore, the present invention does not exclude the inclusion of unavoidable impurities.

[0138] In the optical glass according to this embodiment, Sb ions can be added to suppress a decrease in transmittance at a wavelength of around 360 nm. The upper limit of the Sb ion content is preferably 1.0000 mass% in terms of exclusive percentage, and more preferably 0.5000 mass%, 0.1000 mass%, 0.0900 mass%, 0.0800 mass%, 0.0700 mass%, 0.0600 mass%, 0.0500 mass%, 0.0400 mass%, 0.0300 mass%, 0.0250 mass%, 0.0200 mass%, 0.0150 mass%, 0.0100 mass%, 0.0090 mass%, 0.0080 mass%, 0.0070 mass%, 0.0060 mass%, and 0.0050 mass% in that order. The Sb ion content is preferably 1.0 ppm by mass or more in terms of exclusive percentage. The lower limit of the Sb ion content is more preferably 0.0005 mass%, in terms of exclusive proportion, and even more preferably 0.0008 mass%, 0.0010 mass%, 0.0012 mass%, 0.0014 mass%, 0.0016 mass%, 0.0018 mass%, 0.0020 mass%, 0.0022 mass%, 0.0024 mass%, 0.0026 mass%, 0.0028 mass%, 0.0030 mass%, 0.0032 mass%, 0.0034 mass%, 0.0036 mass%, and 0.0038 mass%, in that order.

[0139] Sb ions can be added to glass, for example, as Sb2O3 or Sb2S3. Sb ions include trivalent, pentavalent, and all other valences. The Sb ion content is an exclusive percentage. That is, the Sb ion content is expressed in mass % when the total content of all glass components other than Sb ions is 100 mass %. From the viewpoint of suppressing a decrease in transmittance at a wavelength around 360 nm, it is preferable to set the Sb ion content within the above range. If the Sb ion content is too high, Pt from the crucible is easily introduced into the glass, forming Pt colloids, which may cause a Tyndall-shaped cloud in the glass and result in a decrease in light transmittance regardless of the wavelength band. Furthermore, the light absorption of the Sb ions themselves may decrease the light transmittance at specific wavelengths. If Sb ions are not contained or the content of Sb ions is too low, the absorption of Pt ions at a wavelength of around 360 nm becomes apparent, which may result in a deterioration in the light transmittance of specific wavelengths in the wavelength range extending to visible light.

[0140] Furthermore, the optical glass can achieve high transmittance over a wide range of the visible light region. To make the most of these features, it is preferable that the glass does not contain any coloring elements. Examples of coloring elements include Cu, Co, Ni, Fe, Cr, Eu, Nd, Er, and V. The content of each element is preferably less than 100 ppm by mass, more preferably 0 to 80 ppm by mass, and even more preferably 0 to 50 ppm by mass, and it is particularly preferable that the glass is substantially free of these elements.

[0141] Ga, Te, Tb, etc. are components that do not need to be incorporated and are expensive components, so the range of the content of Ga2O3, TeO2, and TbO2 expressed in mass% is preferably 0 to 0.1%, more preferably 0 to 0.05%, even more preferably 0 to 0.01%, even more preferably 0 to 0.005%, and even more preferably 0 to 0.001%, and it is particularly preferable that they are not substantially contained.

[0142] (glass properties) <Refractive index nd> In the optical glass according to the first embodiment, the refractive index nd is preferably 1.55 to 1.80, and can also be 1.56 to 1.75, 1.57 to 1.70, 1.58 to 1.65, 1.59 to 1.63, 1.60 to 1.62, or 1.58 to 1.60.

[0143] The refractive index nd can be adjusted to a desired value by appropriately adjusting the content of each glass component. The component that has the function of relatively increasing the refractive index nd (high refractive index component) is Nb 5+ , Ti 4+ , W 6+ , Bi 3+ , Zr 4+ , Ta 5+ , La 3+ , Gd 3+ , Y 3+ On the other hand, the component that acts to relatively lower the refractive index nd (the component that lowers the refractive index) is Si 4+ , B 3+ , Li + , Na + , K. + etc.

[0144] In the optical glass according to the first embodiment, the refractive index nd and the Abbe number vd preferably satisfy the following formula [1-1]. nd≧(-0.0081×νd+2.1181) 〔1-1〕 It is more preferable that the refractive index nd and the Abbe number νd satisfy the following formula [1-2], and more preferably the following formulas [1-3], [1-4], and [1-5] in that order. nd≧(-0.0081×νd+2.1231) 〔1-2〕 nd≧(-0.0081×νd+2.1281) 〔1-3〕 nd≧(-0.0081×νd+2.1331) 〔1-4〕 nd≧(-0.0081×νd+2.1381) 〔1-5〕

[0145] <Partial dispersion ratio Pg,F> In the optical glass according to the first embodiment, the lower limit of the partial dispersion ratio Pg,F in the visible short wavelength region is preferably 0.5200, and more preferably 0.5250, 0.5300, 0.5350, 0.5400, 0.5410, 0.5420, 0.5430, 0.5440, and 0.5450, in that order. By setting the partial dispersion ratio Pg,F within the above range, an optical glass suitable for correcting high-order chromatic aberrations can be obtained. On the other hand, the upper limit of the partial dispersion ratio Pg,F is not particularly limited, but is usually 0.5700, and preferably 0.5650.

[0146] In the optical glass according to the first embodiment, the partial dispersion ratio Pg,F preferably satisfies the following formula [2-1]. Pg,F≧0.6200-0.0014×νd…[2-1] It is more preferable that the partial dispersion ratio Pg,F satisfies the following formula [2-2], and more preferably satisfies the following formula [2-3], the following formula [2-4], the following formula [2-5], and the following formula [2-6] in that order. Pg,F≧0.6220-0.0014×νd … [2-2] Pg,F≧0.6240-0.0014×νd…[2-3] Pg,F≧0.6260-0.0014×νd…[2-4] Pg,F≧0.6280-0.0014×νd…[2-5] Pg,F≧0.6300-0.0014×νd…[2-6]

[0147] In an optical element made of the optical glass according to the first embodiment, from the viewpoint of effectively correcting chromatic aberration over a wide wavelength range, it is preferable that the partial dispersion ratio Pg,F satisfy the above formula.

[0148] In the optical glass according to the first embodiment, the upper limit of ΔPg,F is not particularly limited, but is preferably 0.0500, and further preferably 0.0400, 0.0300, 0.0200, or 0.0150. On the other hand, the lower limit of ΔPg,F is preferably -0.0100, and more preferably -0.0090, -0.0080, -0.0070, -0.0060, -0.0050, -0.0040, -0.0030, -0.0020, -0.0010, 0.0000, 0.0010, 0.0020, 0.0030, 0.0040, 0.0050, 0.0060, 0.0070, 0.0080, 0.0090, 0.0100, 0.0110, 0.0120, and 0.0130, in that order. By setting ΔPg,F within the above range, an optical glass suitable for correcting high-order chromatic aberrations can be obtained.

[0149] The partial dispersion ratio Pg,F is calculated using the above shot dispersion formula. In the present invention, the partial dispersion ratio Pg,F is calculated using the refractive index values ​​measured at 12 different wavelengths (spectral lines) shown in Table A above, by fitting the coefficients of the wavelength term in the equation relating refractive index to wavelength, called the Schott dispersion equation, and then using the dispersion equation after determining these coefficients. By using the refractive index values ​​measured at 12 different wavelengths, the partial dispersion ratio Pg,F can be calculated with high accuracy. On the other hand, it is possible to calculate the partial dispersion ratio Pg,F using a simplified method by reducing the number of wavelengths at which the refractive index is measured, but the accuracy is insufficient.

[0150] The partial dispersion ratio Pg,F is expressed as follows using the refractive indices ng, nF, and nC for the g-line, F-line, and C-line: Pg,F=(ng-nF) / (nF-nC) In addition, in a plane in which the horizontal axis represents the Abbe number νd and the vertical axis represents the partial dispersion ratio Pg,F, the normal line is expressed by the following formula. Pg,F(0)=0.6483-(0.001802×νd) Furthermore, the deviation ΔPg,F of the partial dispersion ratio Pg,F from the normal line is expressed as follows: ΔPg,F=Pg,F-Pg,F(0)

[0151] <Specific gravity of glass> The specific gravity of the optical glass according to the first embodiment is preferably 6.0 or less, and more preferably 5.5 or less, 5.0 or less, 4.8 or less, and 4.6 or less in that order. The component that increases the relative density is Ba. 2+ , La 3+ , Zr 4+ , Nb 5+ , Ta 5+ On the other hand, the components that make the specific gravity lower are Si 4+ , B 3+ , Li + , Na + , Mg 2+ The specific gravity can be controlled by appropriately adjusting the contents of these components.

[0152] <Liquidus temperature LT> The upper limit of the liquidus temperature LT of the optical glass according to the first embodiment is preferably 1200°C, and more preferably 1150°C, 1100°C, 1050°C, 1000°C, 980°C, 970°C, 960°C, 950°C, 940°C, 930°C, 920°C, 910°C, 900°C, and 890°C, in that order. By keeping the liquidus temperature within the above range, the glass melting and forming temperatures can be lowered, thereby reducing corrosion of glass melting equipment (e.g., crucibles, molten glass stirring equipment, etc.) during the melting process and the occurrence of striae due to volatilization of the glass components themselves. There are no particular restrictions on the lower limit of the liquidus temperature LT. The liquidus temperature LT is determined by the balance of the contents of all the glass components. Among these, the liquidus temperature LT is affected by the amount of Si 4+ , B 3+ , Li + , Na + , K. + The content of Zr has a large effect. 4+ , Al 3+ When the content of these elements is high, the liquidus temperature rises.

[0153] The liquidus temperature is determined as follows: 10 cc (10 ml) of glass is placed in a platinum crucible and melted at a temperature of 1200°C or higher for 15 to 30 minutes, then cooled to below the glass transition temperature (Tg). The glass, together with the platinum crucible, is placed in a furnace at the specified temperature and held there for two hours. The holding temperature is set at any temperature in 10°C increments, and after two hours, the glass is cooled and observed for the presence or absence of crystals inside the glass using a 100x optical microscope. This process is repeated for each temperature, and the lowest temperature at which no crystals precipitate is taken as the liquidus temperature.

[0154] <Glass transition temperature Tg> The upper limit of the glass transition temperature Tg of the optical glass according to the first embodiment is preferably 600°C, and more preferably 580°C, 560°C, 540°C, 520°C, 510°C, 500°C, 490°C, 480°C, 470°C, 460°C, 450°C, 440°C, and 430°C, in that order. The lower limit of the glass transition temperature Tg is preferably 350°C, and more preferably 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, and 420°C, in that order. From the viewpoint of improving the yield during precision press molding, it is preferable to set the glass transition temperature Tg within the above range. If the glass transition temperature Tg is too high, precision press molding may not be possible. The component that relatively lowers the glass transition temperature Tg is F - , Li + , Na + , K. + The components that relatively increase the glass transition temperature Tg are Si 4+ , La 3+ , Zr 4+ , Nb 5+ The glass transition temperature Tg can be controlled by appropriately adjusting the content of these components.

[0155] <Light transmittance of glass> The light transmittance of the optical glass according to the first embodiment can be evaluated by the coloring degrees λ80, λ70, and λ5. The spectral transmittance of a glass sample with a thickness of 10.0 mm ± 0.1 mm is measured in the wavelength range of 200 to 700 nm, and the wavelength at which the external transmittance is 80% is defined as λ80, the wavelength at which the external transmittance is 70% is defined as λ70, and the wavelength at which the external transmittance is 5% is defined as λ5.

[0156] The λ80 of the optical glass according to the first embodiment is preferably 450 nm or less, more preferably 400 nm or less, and even more preferably 350 nm or less. The λ70 is preferably 430 nm or less, more preferably 380 nm or less, and even more preferably 330 nm or less. The λ5 is preferably 380 nm or less, more preferably 330 nm or less, and even more preferably 280 nm or less.

[0157] <Mechanical properties Knoop hardness Hk> The lower limit of the Knoop hardness Hk of the optical glass according to the first embodiment is preferably 400, with 410, 420, 430, 440, 450, 460, 470, and 480 being more preferable in that order. The Knoop hardness Hk is preferably set within the above range from the viewpoint of preventing damage when handling the glass and when machining the glass to produce lenses, etc., by grinding, polishing, cutting, etc. The upper limit of the Knoop hardness Hk is not particularly limited, but is typically 750, and preferably 600.

[0158] Knoop hardness Hk is La 3+ , Gd 3+ , Y 3+ , Si 4+ , Zr 4+ , Al 3+ The content can be increased by adjusting the content.

[0159] <ΔT360> In the optical glass according to this embodiment, when the thickness is 10.0 mm ± 0.1 mm, the upper limit of the difference (ΔT360) between the external transmittance at a wavelength of 700 nm and the external transmittance at a wavelength of 360 nm is preferably 31.0%, and more preferably 30.0%, 28.0%, 26.0%, 24.0%, 22.0%, 20.0%, 18.0%, 16.0%, 15.0%, 14.0%, 13.0%, 12.0%, 11.0%, 10.0%, 9.0%, 8.0%, 7.0%, and 6.0%, in that order. The lower limit of ΔT360 is not particularly limited, but is generally 2 to 30%. ΔT360 can be adjusted by introducing Sb ions. In addition, in order to provide a glass with low dispersion in the present application, it is generally not preferable to use high-dispersion components such as Ti, Nb, W, and Bi, but if these are introduced for the purpose of achieving high anomalous dispersion, ΔT360 may increase. By keeping ΔT360 within the above range, it is possible to suppress a decrease in transmittance at a wavelength near 360 nm.

[0160] External transmittance is defined as the percentage of transmitted light intensity relative to incident light intensity when light is incident in the thickness direction of a glass sample [transmitted light intensity / incident light intensity x 100]. Note that external transmittance also includes the reflection loss of light rays on the sample surface.

[0161] (Optical glass manufacturing) The glass according to the first embodiment may be produced by blending glass raw materials to obtain the above-described predetermined composition and using the blended glass raw materials in accordance with a known glass manufacturing method. For example, a plurality of compounds may be blended and thoroughly mixed to form batch raw materials, which are then placed in a platinum crucible or the like and roughly melted (roughly melted). The molten material obtained by rough melting is then rapidly cooled and pulverized to produce cullet. The cullet is then placed in a platinum crucible, heated, and remelted (remelted) to produce a glass melt, which is then clarified and homogenized, and then formed and slowly cooled to obtain an optical glass. Known methods may be used to form and slowly cool the glass melt.

[0162] The compounds used when preparing the batch raw materials are not particularly limited as long as they can introduce desired glass components into the glass in desired contents. Examples of such compounds include oxides, carbonates, nitrates, hydroxides, fluorides, composite oxides, fluorosilicates, and fluoroborates.

[0163] (Manufacturing glass materials for press molding) According to one aspect of the present invention, it is possible to provide a glass material for press molding made of the optical glass according to the first embodiment, and a method for producing the same.

[0164] Press molding of glass materials for press molding can be carried out by pressing the glass material, which has been heated and softened, into a press mold. Both heating and press molding can be carried out in the atmosphere. By uniformly applying a powdered mold release agent such as boron nitride to the surface of the glass material for press molding and then heating and press molding, it is possible to reliably prevent the glass from fusing with the mold and also to smoothly spread the glass along the molding surface of the mold. Annealing the glass after press molding to reduce internal strain in the glass allows for the production of homogeneous optical element blanks.

[0165] Examples of glass materials for press molding include precision press molding preforms and glass materials for press molding optical element blanks (glass gobs for press molding), and include glass chunks having a mass equivalent to the mass of the desired press-molded product.

[0166] Glass materials for press molding, also known as preforms, include those used for press molding as is, as well as those that are subjected to mechanical processing such as cutting, grinding, and polishing before being used for press molding. Cutting methods include forming a groove on the surface of the glass sheet at the desired cutting location using a method called scribing, applying local pressure to the grooved area from the backside of the surface where the groove was formed, thereby breaking the glass sheet at the grooved area, and cutting the glass sheet with a cutting blade. Grinding methods include spherical processing and smoothing using a curve generator. Polishing methods include polishing using abrasive grains such as cerium oxide or zirconium oxide.

[0167] The press-molding glass material according to the first embodiment is made of optical glass with excellent mechanical properties, and is therefore resistant to damage during handling and processing. A problem with conventional precision press-molding glass materials is that scratches on the glass material surface tend to remain on the surface of optical elements after press molding, particularly on optically functional surfaces. The press-molding glass material according to this embodiment has excellent mechanical properties and is resistant to scratches on the glass material surface, making it suitable for use as a precision press-molding glass material. Furthermore, even when the press-molded product is machined, i.e., ground and polished, to produce optical elements after press molding, a press-molded product that is resistant to damage by machining can be produced.

[0168] (Optical element blank manufacturing) According to one aspect of the present invention, it is possible to provide an optical element blank made of the optical glass according to the first embodiment. The optical element blank is a glass molded body having a shape similar to that of the optical element to be manufactured. The optical element blank can be produced by a method of molding glass into a shape that includes a processing allowance to be removed when processing into the shape of the optical element to be manufactured. For example, the optical element blank can be produced by a method of heating and softening a glass material for press molding and press-molding it (reheat press method), or a known method of supplying a molten glass gob to a press mold and press-molding it (direct press method).

[0169] (Optical element manufacturing) To produce an optical element using the optical glass according to the first embodiment, a known method may be applied. For example, the optical element blank described above may be used. Furthermore, for example, in the production of the optical glass, molten glass is poured into a mold and formed into a plate to produce a glass material made of the optical glass according to the present invention. The obtained glass material is appropriately cut, ground, and polished to produce cut pieces of a size and shape suitable for press molding. The cut pieces are heated and softened, and then press-molded (reheat pressed) by a known method to produce an optical element blank that approximates the shape of the optical element. The optical element can be produced by a method including a step of processing the optical element blank. Examples of processing include cutting, cutting, rough grinding, fine grinding, and polishing. Using the above glass during such processing can reduce breakage and ensure a stable supply of high-quality optical elements.

[0170] Examples of types of optical elements include lenses such as spherical lenses and aspherical lenses, prisms, diffraction gratings, etc. Examples of lens shapes include biconvex lenses, plano-convex lenses, biconcave lenses, plano-concave lenses, convex meniscus lenses, concave meniscus lenses, etc. The optically functional surfaces of the optical elements may be coated with an anti-reflection film, a total reflection film, etc. depending on the intended use.

[0171] The optical element according to the first embodiment is made of optical glass with excellent mechanical properties, and therefore is resistant to damage during handling and processing. In particular, the optical element is resistant to damage when fixed. For example, during lens centering, the lens surface is resistant to damage even when clamped from both sides.

[0172] Second embodiment The oxide optical glass according to the second embodiment is The Abbe number νd is 62.00 or more, B 3+ The content of is more than 0 cation% and 50.00 cation% or less, F -The content of is more than 0 anion% and 85 anion% or less, La 3+ , Gd 3+ , and Y 3+ The total content of [La 3+ +Gd 3+ +Y 3+ ] is 5 cation % or more, Si 4+ , B 3+ , P 5+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ , and Ta 5+ La relative to the total content 3+ , Gd 3+ , Y 3+ , Li + , Na + , K. + , Rb + , Cs + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ The cation ratio of the total content [(La 3+ +Gd 3+ +Y 3+ +Li + +Na + +K + +Rb + +Cs + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ) / (Si 4+ +B 3+ +P 5+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+ )] is 0.60 or more, Si 4+ , B 3+ , and P 5+ Si content relative to the total content 4+ and B 3+ The cation ratio of the total content [(Si4+ +B 3+ ) / (Si 4+ +B 3+ +P 5+ )] is 0.2 or more.

[0173] <Abbe number νd> In the optical glass according to the second embodiment, the Abbe number vd is 62.00 or greater. The Abbe number vd is preferably 62 to 75, and can also be 62.2 to 73, 62.4 to 71, 62.6 to 69, 62.8 to 68, 63 to 67, or 62 to 63. The Abbe number vd is calculated in the same manner as in the first embodiment.

[0174] The Abbe number νd can be adjusted to a desired value by appropriately adjusting the content of each glass component. The component that relatively lowers the Abbe number νd, i.e., the high dispersion component, is Nb 5+ , Ti 4+ , Zr 4+ , W 6+ , Bi 3+ , Ta 5+ On the other hand, the component that relatively increases the Abbe number νd, that is, the low dispersion component, is F - , Si 4+ , B 3+ , Li + , Na + , K. + , La 3+ , Ba 2+ , Ca 2+ , Sr 2+ etc.

[0175] In the optical glass according to the second embodiment, B 3+ The content of is more than 0% and not more than 50.00%. 3+ The lower limit of the content of B is preferably 5%, and more preferably 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, and 21% in that order. 3+The upper limit of the content is preferably 45.00%, and more preferably 40.00%, 39.00%, 38.00%, 37.00%, 36.00%, 35.00%, 34.00%, 33.00%, 32.00%, 31.00%, 30.00%, 29.00%, 28.00%, 27.00%, 26.00%, 25.00%, 24.00%, and 23.00% in that order.

[0176] B 3+ is a glass network forming component. 3+ By setting the content of B in the above range, chemical durability can be improved. 3+ If the content of B is too low, the thermal stability and mechanical properties of the glass may be reduced. 3+ If the content is too high, the volatilization of glass components may increase, and the thermal stability and chemical durability of the glass may decrease.

[0177] The optical glass according to the second embodiment contains F as an anion component. - Includes: F - The content of F is greater than 0% and less than 85%. - The lower limit of the content of is preferably 5 anion%, and more preferably 10 anion%, 15 anion%, 20 anion%, 24 anion%, 27 anion%, 30 anion%, 33 anion%, 35 anion%, 37 anion%, 39 anion%, 41 anion%, 43 anion%, 45 anion%, 46 anion%, 47 anion%, 48 anion%, 49 anion%, 50 anion%, 51 anion%, 52 anion%, 53 anion%, 54 anion%, 55 anion%, 56 anion%, and 57 anion% in that order. - The upper limit of the content of is preferably 80 anion%, and more preferably 77 anion%, 75 anion%, 73 anion%, 71 anion%, 69 anion%, 67 anion%, 65 anion%, 64 anion%, 63 anion%, 62 anion%, 61 anion%, 60 anion%, and 59 anion% in that order. -By setting the content of F within the above range, an optical glass can be obtained which has a high refractive index despite its low dispersion, high thermal stability, anomalous partial dispersion, a low glass transition temperature Tg, and is suitable for precision press molding. - If the content of F is too small, the thermal stability of the glass may decrease, and anomalous partial dispersion may not be obtained. - If the content is too large, the volatilization of glass components may increase.

[0178] In the optical glass according to the second embodiment, La 3+ , Gd 3+ , and Y 3+ The total content of [La 3+ +Gd 3+ +Y 3+ ] is 5% or more. The lower limit of the total content is preferably 10%, and more preferably 15%, 20%, 25%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, and 38% in that order. The upper limit of the total content is preferably 60%, and more preferably 55%, 50%, 48%, 46%, 45%, 44%, 43%, 42%, and 41% in that order. By keeping the total content within the above range, an optical glass with a high refractive index nd can be obtained. On the other hand, if the total content is too low, the desired optical constants may not be obtained. If the total content is too high, the thermal stability of the glass may be reduced.

[0179] In the optical glass according to the second embodiment, Si 4+ , B 3+ , P 5+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ , and Ta 5+ La relative to the total content 3+ , Gd 3+ , Y 3+ , Li + , Na + , K. + , Rb + , Cs + , Mg 2+ , Ca2+ , Sr 2+ , and Ba 2+ The cation ratio of the total content [(La 3+ +Gd 3+ +Y 3+ +Li + +Na + +K + +Rb + +Cs + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ) / (Si 4+ +B 3+ +P 5+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+ The lower limit of the cation ratio is preferably 0.70, and more preferably 0.80, 0.90, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, 1.90, 1.95, 2.00, 2.05, 2.10, 2.15, and 2.20 in that order. The upper limit of the cation ratio is preferably 4, and more preferably 3.8, 3.6, 3.4, 3.2, 3.0, 2.9, 2.8, 2.7, 2.65, 2.60, 2.55, 2.50, 2.40, 2.35, 2.30, and 2.25, in that order. By setting the cation ratio within the above range, volatilization of glass components can be suppressed. On the other hand, if the cation ratio is too small, volatilization of glass components may increase. Furthermore, if the cation ratio is too large, the thermal stability of the glass may decrease.

[0180] In the optical glass according to the second embodiment, Si 4+ , B 3+ , and P 5+ Si content relative to the total content 4+ and B 3+ The cation ratio of the total content [(Si 4+ +B 3+ ) / (Si 4++B 3+ +P 5+ )] is 0.2 or more. The lower limit of the cation ratio is preferably 0.3, and more preferably 0.4, 0.5, 0.6, 0.7, 0.8, 0.85, 0.9, and 0.95 in that order. The upper limit of the cation ratio is preferably 1, and more preferably 0.99, 0.98, and 0.97 in that order. The cation ratio may be 1. By setting the cation ratio within the above range, an optical glass having excellent chemical durability and mechanical properties can be obtained.

[0181] In the optical glass according to the second embodiment, the contents and ratios of glass components other than those mentioned above can be the same as those in the first embodiment.

[0182] Furthermore, in the optical glass according to the second embodiment, the glass properties can be the same as those of the first embodiment.

[0183] Furthermore, the production of the optical glass according to the second embodiment, the production of the press-molding glass material, the production of the optical element blank, and the production of the optical element can also be the same as in the first embodiment. [Example]

[0184] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to the embodiments shown in the examples.

[0185] Example 1 Glass samples having the glass compositions shown in Tables 1 to 9 were prepared by the following procedure, and various evaluations were carried out.

[0186] [Optical glass manufacturing] First, oxides, fluorides, hydroxides, carbonates, and nitrates, composite oxides, fluorosilicates, fluoroborates, etc. corresponding to the constituent components of the glass were prepared as raw materials. These raw materials were weighed, blended, and thoroughly mixed so that the resulting optical glass would have the composition shown in Table 1. The blended raw materials (batch raw materials) obtained in this way were placed in a platinum crucible and heated at 1150-1250°C for 1.5-3 hours to form a molten glass. The mixture was stirred to homogenize and refined, and the molten glass was then cast into a mold preheated to an appropriate temperature. The cast glass was heat-treated for 30 minutes at a temperature near the glass transition temperature Tg and allowed to cool to room temperature in a furnace, yielding a glass sample.

[0187] In Table 1 (1) to (9), the content of glass components not shown is 0.00 cation %. For example, in all glass samples, Rb + , Cs + , and Ge 4+ The content of each was 0.00 cation %.

[0188] [ratio of the number of anions to the number of cations] The ratio of the number of anions to the number of cations (anion number / cation number) is the molar ratio of the total number of cations to the total number of anions, and can be calculated from the composition. Specifically, the sum of the positive charges of each cation is calculated when the total number of cations is set to 100 (an arbitrary constant), and the total number of anions is calculated by combining the negative charges of the anions with the same number and the anion molar percentage. From this calculated value, the ratio of the number of anions to the number of cations (anion number / cation number) was calculated.

[0189] [Optical property measurement] The resulting glass samples were further annealed at temperatures near the glass transition temperature (Tg) for approximately 30 minutes to approximately 2 hours, and then cooled to room temperature in a furnace at a rate of -30°C / hour to obtain annealed samples. The refractive index, Abbe number (νd), partial dispersion ratios (Pg,F, ΔPg,F), specific gravity, glass transition temperature (Tg), liquidus temperature (LT), λ80, λ70, λ5, and ΔT360 were measured for the resulting annealed samples. The results are shown in Table 2.

[0190] (i) Refractive indexes nd, ng, nF, nC, Abbe number νd, and partial dispersion ratio Pg,F The refractive index of the annealed sample was measured at the 12 wavelengths shown in Table A according to Japanese Industrial Standards (JIS) JIS B 7071-1, Method for measuring refractive index of optical glass - Part 1: Minimum deviation angle method. Next, the refractive index of each line obtained by measurement was applied to the Schott dispersion formula defined in Appendix B of the Japanese Industrial Standards (JIS) JIS B 7071-1, "Method of measuring the refractive index of optical glass - Part 1: Minimum deviation method," and the constants of the Schott dispersion formula were determined by the least squares method.The Abbe number νd and partial dispersion ratio Pg,F were then calculated using the Schott dispersion formula with the determined constants.

[0191] [Table A] Shot dispersion formula: n 2 =a0+a1λ 2 +a2λ -2 +a3λ -4 +a4λ -6 +a5λ -8 Here, n is the refractive index, λ is the wavelength (μm), and a0, a1, a2, a3, a4, and a5 are constants. The refraction nd is the refractive index at a wavelength of 587.56 nm. The Abbe number νd is expressed as follows using the refractive indices nd, nF, and nC at the d-line, F-line, and C-line, respectively: νd=(nd-1) / (nF-nC) The partial dispersion ratio Pg,F is expressed as follows using the refractive indices ng, nF, and nC for the g-line, F-line, and C-line: Pg,F=(ng-nF) / (nF-nC)

[0192] (ii) ΔPg,F In a plane where the horizontal axis represents the Abbe number νd and the vertical axis represents the partial dispersion ratio Pg,F, the normal line Pg,F(0) is expressed by the following equation. Pg,F(0)=0.6483-(0.001802×νd) is the deviation of the partial dispersion ratio Pg,F from the normal line Δ Pg,F was calculated based on the following formula. ΔPg,F=Pg,F-Pg,F(0)

[0193] (iii) Specific gravity The specific gravity was measured by the Archimedes method.

[0194] (iv) Glass transition temperature Tg The glass transition temperature Tg was measured using a differential scanning calorimeter (DSC3300SA) manufactured by NETZSCH JAPAN at a temperature rise rate of 10°C / min.

[0195] (v) Liquidus temperature LT The glass was placed in a furnace heated to a predetermined temperature and held for about 2 hours. After cooling, the interior of the glass was observed under an optical microscope at 40 to 100 magnifications, and the liquidus temperature was measured from the presence or absence of crystals.

[0196] (vi) λ80, λ70, λ5 The above annealed sample was processed to a thickness of 10 mm to have parallel, optically polished flat surfaces, and its spectral transmittance was measured in the wavelength range from 280 nm to 700 nm. The intensity of the light beam incident perpendicularly to one of the optically polished flat surfaces was defined as intensity A, and the intensity of the light beam emerging from the other flat surface was defined as intensity B, and the spectral transmittance B / A was calculated. The wavelength at which the spectral transmittance was 80% was defined as λ80, the wavelength at which the spectral transmittance was 70% was defined as λ70, and the wavelength at which the spectral transmittance was 5% was defined as λ5. Note that the spectral transmittance also includes the reflection loss of the light beam on the sample surface.

[0197] (vii)ΔT360 The annealed sample was processed to a thickness of 10.0 mm ± 0.1 mm with parallel, optically polished flat surfaces, and its external transmittance was measured at wavelengths of 700 nm and 360 nm. The difference between the external transmittance at 700 nm (T700) and the external transmittance at 360 nm (T360) was calculated and defined as ΔT360.

[0198] External transmittance is defined as the percentage of transmitted light intensity relative to incident light intensity when light is incident in the thickness direction of a glass sample [transmitted light intensity / incident light intensity x 100]. Note that external transmittance also includes the reflection loss of light rays on the sample surface.

[0199] [Mechanical properties Knoop hardness Hk] The obtained glass samples were processed to have a thickness of 2 mm to 20 mm and parallel, optically polished flat surfaces, and the Knoop hardness Hk was measured in accordance with the Japan Optical Glass Industry Association standard JOGIS-09. Specifically, a Knoop indenter was pressed into the processed glass sample, and the Knoop hardness Hk was measured from the size of the indentation. The results are shown in Table 2(1) and (2).

[0200] [Table 1]

[0201] [Table 2]

[0202] [Table 3]

[0203] [Table 4]

[0204] [Table 5]

[0205] [Table 6]

[0206] [Table 7]

[0207] [Table 8]

[0208] [Table 9]

[0209] Example 2 Lens blanks were prepared by known methods using the optical glasses prepared in Example 1, and the lens blanks were processed by known methods such as polishing to prepare various lenses. The optical lenses produced include various lenses such as biconvex lenses, biconcave lenses, plano-convex lenses, plano-concave lenses, concave meniscus lenses, and convex meniscus lenses. By combining the various lenses produced above with a lens made of glass having a smaller Abbe number than the lens, such as flint glass, it was possible to satisfactorily correct high-order chromatic aberrations in the near-ultraviolet to visible range.

[0210] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0211] For example, by adjusting the composition described in the specification to the glass compositions exemplified above, an optical glass according to one aspect of the present invention can be produced. Furthermore, it is of course possible to arbitrarily combine two or more of the items described in the specification as examples or preferred ranges.

Claims

1. Abbe number νd is 62.00 or more, B 3+ The content of is more than 0 cation % and 50.00 cation % or less, Si 4+ The content of exceeds 0 cation%, F - The content of is 35 anion% or more, La 3+ , Gd 3+ , and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 25 cation % or more, Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ and Ta 5+ La relative to the total content 3+ , Gd 3+ , and Y 3+ The cation ratio of the total content [(La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ + Zr 4+ +Ta 5+ ) )] is 0.50 or more, the cation ratio of the total content of La 3+ , Gd 3+ , and Y 3+ to the total content of Si 4+ and B 3+ [(La 3+ + Gd 3+ + Y 3+ ) / (Si 4+ + B 3+ )] is 0.70 or more; Optical glass.

2. Si 4+ , B 3+ , P 5+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ , and Ta 5+ La relative to the total content 3+ , Gd 3+ , Y 3+ , Li + , Na + , K. + , Rb + , Cs + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ The cation ratio of the total content [(La 3+ +Gd 3+ +Y 3+ +Li + +Na + +K + +Rb + +Cs + + Mg 2+ + Ca 2+ + Sr 2+ +Ba 2+ ) / (Si 4+ +B 3+ +P 5+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ + Zr 4+ +Ta 5+ ) )] is 0.50 or more, The optical glass according to claim 1 .

3. Abbe number νd is 62.00 or more, B 3+ The content of is more than 0 cation % and 50.00 cation % or less, F - The content of is 35 to 85 anion %, La 3+ , Gd 3+ , and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 25 cation % or more, Si 4+ , B 3+ , P 5+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ , and Ta 5+ La relative to the total content 3+ , Gd 3+ , Y 3+ , Li + , Na + , K. + , Rb + , Cs + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ The cation ratio of the total content [(La 3+ +Gd 3+ +Y 3+ +Li + +Na + +K + +Rb + +Cs + + Mg 2+ + Ca 2+ + Sr 2+ +Ba 2+ ) / (Si 4+ +B 3+ +P 5+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ + Zr 4+ +Ta 5+ ) )] is 0.60 or more, Si 4+ , B 3+ , and P 5+ Si content relative to the total content 4+ and B 3+ The cation ratio of the total content [(Si 4+ +B 3+ ) / (Si 4+ +B 3+ +P 5+ ) )] is 0.2 or more, Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Zr 4+ and Ta 5+ La relative to the total content 3+ , Gd 3+ , and Y 3+ The cation ratio of the total content [(La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ + Zr 4+ +Ta 5+ ) )] is 0.50 or more, the cation ratio of the total content of La 3+ , Gd 3+ , and Y 3+ to the total content of Si 4+ and B 3+ [(La 3+ + Gd 3+ + Y 3+ ) / (Si 4+ + B 3+ )] is 0.70 or more; Optical glass.

4. The optical glass according to any one of claims 1 to 3, which satisfies one or more of the following: Si 4+ , B 3+ , and P 5+ The total content [Si 4+ +B 3+ +P 5+ ] is 10 to 48 cation %. Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ Li relative to the total content + , Na + , K. + , Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , La 3+ , Gd 3+ , and Y 3+ The cation ratio of the total content [(Li + +Na + +K + + Mg 2+ + Ca 2+ + Sr 2+ +Ba 2+ +La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ) is 1.05 or more.

5. The optical glass according to any one of claims 1 to 3, which satisfies one or more of the following: Si 4+ and B 3+ The total content [Si 4+ +B 3+ ] is 10 to 48 cation %. Si 4+ , B 3+ , and P 5+ Si content relative to the total content 4+ The cation ratio of the content [Si 4+ / (Si 4+ +B 3+ +P 5+ ) )] is 0.020 to 0.

80. Si 4+ , B 3+ , and P 5+ B relative to the total content of 3+ The cation ratio of the content [B 3+ / (Si 4+ +B 3+ +P 5+ ) )] is 0.20 to 0.

980. Si 4+ , B 3+ , and P 5+ P relative to the total content of 5+ The cation ratio of the content [P 5+ / (Si 4+ +B 3+ +P 5+ ) )] is 0 to 0.

50. , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ Ba relative to the total content of 2+ The cation ratio of the content [Ba 2+ / (Mg 2+ + Ca 2+ + Sr 2+ +Ba 2+ ) )] is 0.1 to 1. Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and Zn 2+ Ba relative to the total content of 2+ The cation ratio of the content [Ba 2+ / (Mg 2+ + Ca 2+ + Sr 2+ +Ba 2+ +Zn 2+ ) )] is 0.1 to 1. La 3+ , Gd 3+ , and Y 3+ Y relative to the total content of 3+ The cation ratio of the content [Y 3+ / (La 3+ +Gd 3+ +Y 3+ ) )] is 0.05 to 1. Si 4+ and B 3+ Al content relative to the total content 3+ The cation ratio of the content [Al 3+ / (Si 4+ +B 3+ ) )] is 0 to 0.

5. Li + , Na + , K. + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ Al content relative to the total content 3+ The cation ratio of the content [Al 3+ / (Li + +Na + +K + + Mg 2+ + Ca 2+ + Sr 2+ +Ba 2+ ) )] is 0 to 5. La 3+ , Gd 3+ , and Y 3+ Al content relative to the total content 3+ The cation ratio of the content [Al 3+ / (La 3+ +Gd 3+ +Y 3+ ) )] is 0 to 2. Si 4+ and B 3+ La relative to the total content 3+ , Gd 3+ , and Y 3+ The cation ratio of the total content [(La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+ ) )] is 0.70 to 3. Si 4+ and B 3+ Li relative to the total content of + , Na + , K. + , Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , La 3+ , Gd 3+ , and Y 3+ The cation ratio of the total content [(Li + +Na + +K + + Mg 2+ + Ca 2+ + Sr 2+ +Ba 2+ +La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+ ) )] is 0.01 to 4. Si 4+ , B 3+ , Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ La relative to the total content 3+ , Gd 3+ , and Y 3+ The cation ratio of the total content [(La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ) )] is 0.01 to 3.

6. The optical glass according to any one of claims 1 to 3, which satisfies one or more of the following: P 5+ The content is 0 to 30 cation %. Al 3+ The content is 0 to 30 cation %. Li + The content is 0 to 40 cation %. Na + The content is 0 to 40 cation %. K + The content is 0 to 40 cation %. Rb + The content is 0 to 40 cation %. Cs + The content is 0 to 40 cation %. Mg 2+ The content is 0 to 40 cation %. Sr 2+ The content is 0 to 40 cation %. Ba 2+ The content is 0 to 40 cation %. La 3+ The content is 5 to 50 cation %. Gd 3+ The content is 0 to 50 cation %. Y 3+ The content is 0 to 50 cation %. Yb 3+ The content is 0 to 50 cation %. Ti 4+ The content is 0 to 20 cation %. Nb 5+ The content is 0 to 20 cation %. W 6+ The content is 0 to 20 cation %. Bi 3+ The content is 0 to 20 cation %. Ta 5+ The content is 0 to 10 cation %. Zr 4+ The content is 0 to 10 cation %. Sc 3+ The content is 0 to 2 cation %. Hf 4+ The content is 0 to 2 cation %. Lu 3+ The content is 0 to 2 cation %.

7. Si 4+ , B 3+ , Ca 2+ , Zn 2+ , P 5+ , Al 3+ , Li + , Na + , K. + , Rb + , Cs + , Mg 2+ , Sr 2+ , Ba 2+ , La 3+ , Gd 3+ , Y 3+ , Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , Ta 5+ , and Zr 4+ 4. The optical glass according to claim 1, wherein the total content of is 95 cation % or more.

8. The optical glass according to any one of claims 1 to 3, which satisfies one or more of the following: O 2- The content of is 10 to 90 anion %. Cl - The content of anions is less than 5%. Br - and I - The total content of these anions is less than 5%. The content of each of Cu, Co, Ni, Fe, Cr, Eu, Nd, Er, and V is less than 100 ppm by mass. Ga 2 O 3 , TeO 2 , and TbO 2 The content of each of these is 0 to 0.1 mass %.

9. The optical glass according to any one of claims 1 to 3, which satisfies one or more of the following: The refractive index nd is 1.55 to 1.

80. The refractive index nd and the Abbe number νd satisfy the following formula [1-1]. nd≧(−0.0081×νd+2.1181) ... [1-1] The partial dispersion ratio Pg, F satisfies the following formula [2-1]. Pg,F≧0.6200-0.0014×νd…[2-1] ΔPg,F is −0.0100 to 0.0500. The liquidus temperature LT is 1200°C or lower. The glass transition temperature Tg is 350 to 600°C. The Knoop hardness Hk is 400 to 750.

10. The optical glass according to any one of claims 1 to 3, which satisfies one or more of the following: Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ The total content [Mg 2+ + Ca 2+ + Sr 2+ +Ba 2+ ] is 0 to 30 cation %. Li + , Na + , K. + , Rb + , Cs + , Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ The total content [Li + +Na + +K + +Rb + +Cs + + Mg 2+ + Ca 2+ + Sr 2+ +Ba 2+ ] is 0 to 50 cation %. Ca 2+ The content is 0 to 25 cation %. Ge 4+ The content is 0 to 5 cation %. Zn 2+ The content is 0 to 13 cation %. Si 4+ and B 3+ Si content relative to the total content 4+ The cation ratio of the content [Si 4+ / (Si 4+ +B 3+ ) )] is 0.020 to 0.

80.

11. 4. The optical glass according to claim 1, wherein the content of Sb ions is 1.0 mass ppm or more in terms of exclusive proportion.

12. 4. The optical glass according to claim 1, wherein the difference between the external transmittance at a wavelength of 700 nm and the external transmittance at a wavelength of 360 nm is 10% or less when the thickness is 10.0 mm±0.1 mm.

13. A glass material for press molding, comprising the optical glass according to any one of claims 1 to 3.

14. An optical element made of the optical glass according to any one of claims 1 to 3.

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