Optical glass and optical element

Abstract

The present invention provides an optical glass and an optical element which have a desired optical constant, are suppressed in reduction of chemical durability and mechanical characteristics, and have a low glass transition temperature. In the optical glass, the content of Si < 4 + > is more than 0 cation% and less than 30 cation%, the content of B < 3 + > is more than 0 cation% and less than 50.00 cation%, the content of F <-> is more than 10 anion%, the content of Ca < 2 + > is less than 25 cation%, the content of Zn < 2 + > is less than 13 cation%, the content of Ge < 4 + > is less than 5 cation%, and the total content of La < 3 + >, Gd < 3 + > and Y < 3 + > [La < 3 + > + Gd < 3 + > + Y < 3 + >] is more than 30 cation%. The total content of Mg < 2 + >, Ca < 2 + >, Sr < 2 + > and Ba < 2 + > [Mg < 2 + > + Ca < 2 + > + Sr < 2 + > + Ba < 2 + >] is 3.5 cation% or more, the total content of Li < + >, Na < + >, K < + >, Rb < + >, Cs < + >, Mg < 2 + >, Ca < 2 + >, Sr < 2 + > and Ba < 2 + > [Li < + > + Na < + > + K < + > + Rb < + > + Cs < + >] is 3.5 cation% or more, the cation ratio of the content of Si < 4 + > to the total content of Si < 4 + > and B < 3 + > [Si < 4 + > / (Si < 4 + > + B < 3 + >

Description

Technical Field

[0001] The present invention relates to optical glass and optical elements having desired optical properties. Background Art

[0002] Lenses with high refractive index and anomalous partial dispersion in each Abbe region have been widely used in digital cameras such as car cameras and SLR cameras, as well as mobile information terminals such as smart phones. In order to improve the yield rate during lens manufacturing in these applications, it is desirable that the glass have high chemical durability and mechanical properties. In addition, for example, when processing glass into aspheric lenses, processing sometimes becomes difficult for glass with a high glass transition temperature. Therefore, glass with a lower glass transition temperature is required.

[0003] Patent Document 1 discloses an optical glass having a high refractive index and anomalous partial dispersion in the visible to near-ultraviolet region. Patent Document 2 also discloses an optical glass having a high refractive index and high transmittance in the near-infrared region. However, neither Patent Document 1 nor Patent Document 2 addresses the improvement of mechanical properties.

[0004] Therefore, there is a demand for glass having chemical durability, a low glass transition temperature, a high refractive index, and abnormal partial dispersion while also having mechanical properties.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-155745

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2017-19670

[0009] Summary of the Invention

[0010] Problems to be solved by the invention

[0011] The present invention has been made in view of such actual circumstances, and an object thereof is to provide an optical glass and an optical element having desired optical constants, with reduced degradation of chemical durability and mechanical properties, and with a low glass transition temperature.

[0012] Solutions to the problem

[0013] The gist of the present invention is as follows.

[0014] (1) An optical glass, wherein:

[0015] Si 4+ The content of cations is greater than 0% and less than 30%.

[0016] B3+ The content of cations is greater than 0% and less than 50.00%.

[0017] F - The content of anions is 10% or more,

[0018] Ca 2+ The content of cationic ions is less than 25%,

[0019] Zn 2+ The content of cationic ions is less than 13%,

[0020] Ge 4+ The content of cationic ions is less than 5%,

[0021] La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 30 cation % or more,

[0022] Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ] is 3.5 cation % or more,

[0023] 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 3.5 cation % or more,

[0024] Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4++B 3+ )] is 0.020 or more,

[0025] La 3+ 、Gd 3+ 、Y 3+ 、Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3 + 、P 5+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 above 0.83.

[0026] (2) An optical glass, wherein:

[0027] Si 4+ The content of cations is greater than 0% and less than 30%.

[0028] B 3+ The content of cations is greater than 0% and less than 50.00%.

[0029] F - The content of anions is 10% or more,

[0030] Ca2+ The content of cationic ions is less than 25%,

[0031] Zn 2+ The content of cationic ions is less than 13%,

[0032] Ge 4+ The content of cationic ions is less than 5%,

[0033] La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 27 cation % or more,

[0034] Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ] is 3.5 cation % or more,

[0035] 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 3.5 cation % or more,

[0036] Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is 0.070 or more,

[0037] La 3+ 、Gd 3+ 、Y 3+ 、Li + 、Na+ , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3 + 、P 5+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 0.83 or more,

[0038] Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content [Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ] is greater than 0 cation %.

[0039] (3) An optical glass, wherein:

[0040] Si 4+ The content of cations is greater than 0% and less than 30%.

[0041] B 3+ The content of cations is greater than 0% and less than 50.00%.

[0042] Al3+ The content of cationic ions is less than 13%,

[0043] Ca 2+ The content of cationic ions is less than 25%,

[0044] Zn 2+ The content of cationic ions is less than 6%,

[0045] Ge 4+ The content of cationic ions is less than 5%,

[0046] F - The content of anions is 10% or more,

[0047] La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 30 cation % or more,

[0048] Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is 0.070 or more,

[0049] La 3+ 、Gd 3+ 、Y 3+ 、Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3 + 、P 5+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 above 0.84.

[0050] (4) An optical glass, wherein:

[0051] B 3+ The content of cations is greater than 0% and less than 50.00%.

[0052] La 3+ The content of cations is greater than 0% and less than 70%.

[0053] Zn 2+ The content of cationic ions is less than 6.5%,

[0054] F - The content of anions is 10% or more,

[0055] La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 30 cation % or more,

[0056] Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content [Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ] less than 2.0 cation%,

[0057] Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is below 0.77,

[0058] La3+ 、Gd 3+ 、Y 3+ 、Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3 + 、P 5+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 0.84 or more,

[0059] The content of Sb ions is 1.0 mass ppm or more in terms of added ratio,

[0060] When the thickness is set to 10.0 mm±0.1 mm, 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.

[0061] (5) An optical glass, wherein:

[0062] B 3+ The content of cations is greater than 0% and less than 50.00%.

[0063] La 3+ The content of cations is greater than 0% and less than 70%.

[0064] Zn 2+ The content of cationic ions is less than 6.5%,

[0065] F - The content of anions is 10% or more,

[0066] La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 30 cation % or more,

[0067] Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content [Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ] is 2.0 cation % or more,

[0068] Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is below 0.77,

[0069] La 3+ 、Gd 3+ 、Y 3+ 、Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3 + 、P 5+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 0.84 or more,

[0070] The content of Sb ions is 1.0 mass ppm or more in terms of added ratio,

[0071] When the thickness is set to 10.0 mm±0.1 mm, the difference between the external transmittance at a wavelength of 700 nm and the external transmittance at a wavelength of 375 nm is 7.5% or less.

[0072] (6) A press-molding glass material made of the optical glass described in any one of (1) to (5) above.

[0073] (7) An optical element made of the optical glass described in any one of (1) to (5) above.

[0074] Effects of the Invention

[0075] According to the present invention, it is possible to provide an optical glass and an optical element having desired optical constants, suppressed degradation of chemical durability and mechanical properties, and not high glass transition temperature. DETAILED DESCRIPTION

[0076] In the embodiments of the present invention, unless otherwise specified, the glass composition of optical glass is expressed in terms of cation %. Cation % refers to the molar percentage when the total content of all cationic components is taken as 100%. Unless otherwise specified, the content and total content of glass components are based on cation %, and "%" refers to "cation %." Furthermore, the cation ratio refers to the ratio (ratio) of the contents of the respective cation components within the cation % (including the total content of multiple cation components).

[0077] In addition, anion % means the molar percentage when the total content of all anion components is set to 100%.

[0078] The valence of the cationic component (e.g. B 3+ The valence is +3, Si4+ The valence is +4, La 3+ The valence of the glass is +3) is a value determined by convention. When expressing B, Si, and La as glass components based on oxides, it is the same as expressing them as B2O3, SiO2, and La2O3. Therefore, when analyzing glass composition, the valence of the cationic components can be ignored. In addition, the valence of the anionic components (such as O 2- The valence of the anion is -2) is also a value determined by convention. As mentioned above, the glass composition expressed on an oxide basis is the same as, for example, B2O3, SiO2, and La2O3. Therefore, when analyzing the glass composition, the valence of the anion component does not need to be analyzed.

[0079] The content of the glass component can be quantified by known methods, such as inductively coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), ion chromatography (IC), non-dispersive infrared absorption spectrometry (ND-IR), etc. In this specification and the present invention, a content of a constituent component of 0% means that the constituent component is substantially not contained, but the presence of the constituent component at a level of unavoidable impurities is permitted.

[0080] In this specification, chemical durability refers to excellence in either or both of acid resistance Da and water resistance Dw. In addition, mechanical properties refer to excellence in the hardness of the glass as evaluated by the Knoop hardness Hk. The Knoop hardness Hk is an indicator of the indentation hardness of the glass. It should be noted that the unit of the Knoop hardness Hk is "MPa", but due to the convention of omitting the unit of the Knoop hardness Hk in the technical field to which the present invention belongs, the unit of the Knoop hardness Hk is also omitted in this specification. In addition, the thermal stability and reheating stability of the glass both refer to the ease with which crystals in the glass precipitate. Thermal stability refers to the ease with which crystals precipitate when molten glass solidifies, and reheating stability refers to the ease with which crystals precipitate when the solidified glass is reheated, such as during re-hot pressing.

[0081] In this specification, reducing or suppressing the volatilization of glass components means that the loss of glass components caused by the volatilization of glass components during melting is small or suppressed. If the loss of glass components caused by volatilization during melting is small, the fluctuation of various properties represented by the refractive index can be suppressed, and the generation of internal defects such as ribs inside the glass can be suppressed, so that the quality can be stabilized. In addition, by reducing the loss of glass components, the yield of the product relative to the input raw materials can be directly improved. On the other hand, the glass components that are easily volatilized during melting are components that help to reduce dispersion, improve the dispersion of abnormal parts, and lower the glass transition temperature Tg. Therefore, by suppressing the volatilization of these components, optical glass and optical elements with desired optical constants and low glass transition temperature Tg can be provided.

[0082] Unless otherwise specified, the refractive index refers to the refractive index nd under helium d-ray (wavelength 587.56 nm).

[0083] Hereinafter, the optical glass of the present invention will be described as a first embodiment and a second embodiment.

[0084] First embodiment

[0085] In the optical glass of the first embodiment,

[0086] Si 4+ The content of cations is greater than 0% and less than 30%.

[0087] B 3+ The content of cations is greater than 0% and less than 50.00%.

[0088] F - The content of anions is 10% or more,

[0089] Ca 2+ The content of cationic ions is less than 25%,

[0090] Zn 2+ The content of cationic ions is less than 13%,

[0091] Ge 4+ The content of cationic ions is less than 5%,

[0092] La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 30 cation % or more,

[0093] Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ] is 3.5 cation % or more,

[0094] Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba2+ The total content [Li + +Na + +K + +Rb + +Cs + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ] is 3.5 cation % or more,

[0095] Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is 0.020 or more,

[0096] La 3+ 、Gd 3+ 、Y 3+ 、Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3 + 、P 5+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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+ +Bi3+ +Zr 4+ +Ta 5+ )] is above 0.83.

[0097] In the optical glass of the first embodiment, Si 4+ The content of Si is greater than 0% and less than 30%. 4+ The lower limit of the content of Si is preferably 1%, and more preferably 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%. 4+ The upper limit of the content is preferably 25%, and more preferably 23%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, and 13% in this order.

[0098] Si 4+ It is a network forming component of glass. 4+ When the content of Si is within the above range, an optical glass having improved abnormal partial dispersion, chemical durability, mechanical properties and thermal stability can be obtained. 4+ If the content of Si is too low, there is a risk that the chemical durability, mechanical properties and thermal stability of the glass will be reduced. 4+ If the content of MgO is too high, the solubility of the glass may be reduced, and the refractive index nd may be reduced. In addition, the thermal stability of the glass may be reduced, and the glass transition temperature Tg may be increased.

[0099] In the optical glass of the first embodiment, B 3+ The content of B is greater than 0% and less than 50.00%. 3+ The lower limit of the content of is preferably 5%, and more preferably 10%, 15%, 17%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, and 26%. 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%, and 29.00%.

[0100] B 3+ It is a network forming component of glass. 3+ The chemical durability can be improved by setting the content of B in the above range. 3+ If the content of B is too low, there is a risk of reducing the thermal stability and mechanical properties of the glass. 3+ When the content of is too high, there is a risk that the volatilization of glass components increases, and there is a risk that the thermal stability and chemical durability of the glass decrease.

[0101] The optical glass of the first embodiment includes F - As anionic component. - The content of anion is 10% or more. - The lower limit of the content of is preferably 15 anion%, and further preferably 20 anion%, 25 anion%, 27 anion%, 29 anion%, 30 anion%, 31 anion%, 32 anion%, 33 anion%, 34 anion%, 35 anion%, 36 anion%, 37 anion%, 38 anion%, 39 anion%, 40 anion%, 41 anion%, 42 anion%, 43 anion%, and 44 anion%. In addition, F - The upper limit of the content of is preferably 80 anion%, and further more preferably 75 anion%, 70 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%. By adding F - By setting the content of F in the above range, an optical glass having high refractive index, high thermal stability, abnormal partial dispersion, low glass transition temperature Tg, and suitable for precision press molding can be obtained despite having low dispersion. - If the content of F is too low, there is a risk that the thermal stability of the glass will be reduced, and there is a risk that the abnormal partial dispersion property cannot be obtained. - When the content is too high, there is a risk of increased volatilization of glass components.

[0102] In the optical glass of the first embodiment, Ca 2+ The content of Ca is less than 25%. 2+ The upper limit of the content of Ca is preferably 20%, and more preferably 15%, 10%, 9%, 8%, 7%, 6%, and 5%. 2+ The lower limit of the content of Ca is preferably 0%, and more preferably 0.5%, 1%, and 2% in that order. 2+ The content can be 0%.

[0103] By adding Ca 2+ When the content of Ca is within the above range, an optical glass having desired optical constants can be obtained. 2+ When the content of MgO is too high, the thermal stability of the glass is impaired, and there is a risk that the glass transition temperature Tg and the liquidus temperature TL may increase.

[0104] In the optical glass of the first embodiment, Zn2+ The content of Zn is less than 13%. 2+ The upper limit of the content of Zn is preferably 10%, and more preferably 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 can be 0%.

[0105] Zn 2+ It is a glass component that has the effect of lowering the glass transition temperature Tg by introduction. 2+ When the content of Zn is within the above range, an optical glass having an improved glass transition temperature Tg can be obtained. 2+ When the content of is too high, there is a risk that the specific gravity increases, and there is a risk that the thermal stability and chemical durability of the glass decrease. In addition, the Abbe number increases, and as a result, there is a risk that the desired high refractive index characteristics cannot be obtained.

[0106] In the optical glass of the first embodiment, Ge 4+ The content of Ge is less than 5%. 4+ The upper limit of the content of Ge is preferably 4.5%, and more preferably 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, and 0.5%. 4+ The lower limit of the content of Ge is preferably 0%. 4+ The content can be 0%.

[0107] Ge 4+ It has the function of improving the dispersion of glass and is an especially expensive component among the commonly used glass components. 4+ Setting the content of MgO within the above range can reduce the manufacturing cost of the glass.

[0108] In the optical glass of the first embodiment, La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+] is 30% or more. The lower limit of the total content is preferably 31%, and more preferably 32%, 33%, 34%, 35%, 36%, 37%, and 38% in that order. In addition, 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 setting 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, there is a risk that the desired optical constants cannot be obtained. If the total content is too high, there is a risk that the thermal stability of the glass is reduced.

[0109] In the optical glass of the first embodiment, Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2 + ] is 3.5% or more. The lower limit of the total content is preferably 5%, and further preferably 7%, 9%, 10%, 11%, 12%, and 13%. In addition, the upper limit of the total content is preferably 30%, and further more preferably 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, and 16%. By setting the total content to the above range, an optical glass having desired optical constants, reduced volatilization of glass components, and high thermal stability of the glass can be obtained. On the other hand, when the total content is too small, there is a risk of increased volatilization of glass components and reduced thermal stability and devitrification resistance of the glass. In addition, when the total content is too much, there is a risk of damaging the high refractive index and the thermal stability of the glass.

[0110] In the optical glass of the first embodiment, 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 3.5% or more. The lower limit of the total content is preferably 5%, and more preferably 7%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, and 20%. In addition, the upper limit of the total content is preferably 40%, and more preferably 39%, 38%, 37%, 36%, 35%, 34%, 33%, 32%, 31%, 30%, 29%, 28%, 27%, 26%, 25%, 24%, and 23%. By setting the total content within the above range, an optical glass having desired optical constants, a lower glass transition temperature Tg, reduced volatilization of glass components, and high thermal stability can be obtained.

[0111] In the optical glass of the first embodiment, Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is 0.020 or more. The lower limit of the cation ratio is preferably 0.05, and more preferably 0.09, 0.13, 0.15, 0.17, 0.19, 0.21, 0.22, 0.23, 0.24, and 0.25. In addition, 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. By setting the cation ratio within the above range, an optical glass with improved chemical durability, mechanical properties, and thermal stability can be obtained.

[0112] In the optical glass of the first embodiment, La 3+ 、Gd 3+ 、Y 3+ 、Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、P 5+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 0.83 or more. The lower limit of the cation ratio is preferably 0.90, and more preferably 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, and 1.50. In addition, the upper limit of the cation ratio is preferably 5.00, and more preferably 4.00, 3.00, 2.50, 2.30, 2.10, 2.00, 1.90, 1.85, 1.80, 1.75, 1.70, and 1.65. By setting the cation ratio within the above range, the volatilization of the glass components can be suppressed. On the other hand, if the cation ratio is too low, there is a risk of increased volatilization of the glass components. In addition, if the cation ratio is too high, there is a risk of reduced thermal stability of the glass.

[0113] Hereinafter, non-limiting examples are shown regarding the contents and ratios of glass components other than those described above in the optical glass of the first embodiment.

[0114] In the optical glass of the first embodiment, Si 4+ and B 3+ The total content [Si 4+ +B 3+ The lower limit of the total content is preferably 10%, and more preferably 15%, 20%, 22%, 24%, 26%, 28%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, and 37%. In addition, 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%, and 40%. From the viewpoint of obtaining an optical glass having desired optical constants and anomalous partial dispersion, improving chemical durability, mechanical properties, and thermal stability, and suppressing volatilization of glass components during melting, the total content is preferably within the above range.

[0115] In the optical glass of the first embodiment, Li + 、Na + and K + The total content [Li + +Na + +K + The lower limit of the total content is preferably 0%, and more preferably 1%, 2%, 3%, 4%, 5%, and 6%. Furthermore, the upper limit of the total content is preferably 50%, and more preferably 45%, 40%, 35%, 30%, 25%, 20%, 18%, 16%, 14%, 13%, 12%, 11%, 10%, and 9%. The total content may be 0%. From the perspective of lowering the liquidus temperature of the glass and lowering the glass transition temperature Tg, the total content is preferably within the above range.

[0116] In the optical glass of the first embodiment, Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+ The upper limit of the total content is preferably 50%, and more preferably 45%, 40%, 35%, 30%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, and 16%. The lower limit of the total content is preferably 3.5%, and more preferably 7%, 9%, 10%, 11%, 12%, and 13%. If the total content is too high, there is a risk of impairing the high refractive index and the thermal stability of the glass. On the other hand, if the total content is too low, there is a risk of increased volatilization of glass components and reduced thermal stability and devitrification resistance of the glass. Therefore, the total content is preferably within the above range.

[0117] In the optical glass of the first embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content [Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+The lower limit of the total content is preferably 3.5%, and more preferably 7%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, and 20%. In addition, the upper limit of the total content is preferably 50%, and more preferably 45%, 40%, 35%, 32%, 30%, 29%, 28%, 27%, 26%, 25%, 24%, and 23%. From the viewpoint of obtaining an optical glass having desired optical constants, lowering the glass transition temperature Tg and the liquidus temperature of the glass, and reducing the volatilization of the glass components during melting, it is preferable to set the total content within the above range.

[0118] In the optical glass of the first embodiment, Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content [Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ] 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 addition, the upper limit of the total content is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5%. From the perspective of maintaining high refractive index and low dispersion, the total content may be 0%. In addition, from the perspective of maintaining the desired Abbe number νd and improving the anomalous partial dispersion in the visible to near-ultraviolet region, it is preferred that the total content be within the above range.

[0119] In the optical glass of the first embodiment, Zr 4+ and Ta 5+ The total content [Zr 4+ +Ta 5+ The upper limit of the total content is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3%, 2%, and 1%. Furthermore, the lower limit of the total content is preferably 0%, and more preferably 0.1%, 0.2%, and 0.3%. To maintain high refractive index and low dispersion, the total content may be 0%. Furthermore, to maintain the thermal stability of the glass, the total content is preferably within the above range. Excessive total content may reduce the thermal stability of the glass and increase raw material costs.

[0120] In the optical glass of the first embodiment, Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta5+ The total content [Ti 4+ +Nb 5+ +Bi 3+ +W 6+ +Zr 4+ +Ta 5+ The upper limit of the total content is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5% in this order. In addition, 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 this order. From the perspective of maintaining high refractive index and low dispersion, the total content may be 0%. In addition, from the perspective of maintaining the desired Abbe number νd and improving the anomalous partial dispersion in the visible to near-ultraviolet region, it is preferred that the total content be within the above range.

[0121] In the optical glass of the first embodiment, B 3+ The content relative to Si 4+ and B 3+ The total 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, respectively. Furthermore, 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, respectively. From the perspective of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above range.

[0122] In the optical glass of the first embodiment, Si 4+ 、B 3+ and P 5+ The total content [Si 4+ +B 3+ +P 5+The lower limit of the total content is preferably 10%, and more preferably 15%, 20%, 22%, 24%, 26%, 28%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, and 37%. In addition, 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%, and 40%. From the viewpoint of obtaining an optical glass having desired optical constants and anomalous partial dispersion, improved chemical durability, mechanical properties, and thermal stability, and suppressed volatilization of glass components during melting, the total content is preferably within the above range.

[0123] In the optical glass of the first embodiment, Si 4+ The content relative to Si 4+ 、B 3+ and P 5+ The total content of cations is [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, respectively. Furthermore, 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, respectively. From the perspective of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above range.

[0124] In the optical glass of the first embodiment, B 3+ The content relative to Si 4+ 、B 3+ and P 5+ The total 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, respectively. Furthermore, 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, respectively. From the perspective of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above range.

[0125] In the optical glass of the first embodiment, P 5+ The content relative to Si 4+ 、B 3+ and P 5+ The total 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. Furthermore, the lower limit of the cation ratio is preferably 0, and more preferably 0.005, 0.01, and 0.015. The cation ratio may be 0. From the perspective of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above range.

[0126] In the optical glass of the first embodiment, Li + The content relative to Li + 、Na + and K + The total cation content ratio [Li + / (Li + +Na + +K + The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, or 0.85. In addition, 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, or 0.7. The cation ratio may be 1. From the perspective of suppressing a decrease in stability during reheating and lowering the glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0127] In the optical glass of the first embodiment, Na + The content relative to Li + 、Na + and K + The total cation 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, or 0.3 in that order. Furthermore, the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, or 0.15 in that order. The cation ratio may be 0. From the perspective of suppressing a decrease in stability during reheating and lowering the glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0128] In the optical glass of the first embodiment, K + The content relative to Li + 、Na + and K + The total content of cation ratio [K + / (Li + +Na + +K + The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, or 0.3 in that order. Furthermore, the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, or 0.15 in that order. The cation ratio may be 0. From the perspective of suppressing a decrease in stability during reheating and lowering the glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0129] In the optical glass of the first embodiment, Mg 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total cation content ratio [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, 0.5, 0.45, and 0.4. 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, and 0.3. The cation ratio may be 0. From the viewpoint of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0130] In the optical glass of the first embodiment, Ca 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total cation content ratio [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, or 0.15. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 or 0.1. The cation ratio may be 0. From the perspective of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0131] In the optical glass of the first embodiment, Sr 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content of cation ratio [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, or 0.15. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 or 0.1. The cation ratio may be 0. From the perspective of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0132] In the optical glass of the first embodiment, Ba 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content of cation ratio [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, 0.50, 0.55, and 0.60. 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, and 0.70. From the viewpoint of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0133] In the optical glass of the first embodiment, Mg 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+and Zn 2+ The total cation content ratio [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, 0.5, 0.45, and 0.4. 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, and 0.3. The cation ratio may be 0. From the viewpoint of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0134] In the optical glass of the first embodiment, Ca 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ The total cation content ratio [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, or 0.15. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 or 0.1. The cation ratio may be 0. From the perspective of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0135] In the optical glass of the first embodiment, Sr 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ The total content of cation ratio [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, or 0.15. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 or 0.1. The cation ratio may be 0. From the perspective of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0136] In the optical glass of the first embodiment, Ba 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ The total content of cation ratio [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 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, and 0.60. 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, and 0.70. The cation ratio may be 0. From the viewpoint of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0137] In the optical glass of the first embodiment, Zn 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ The total 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, or 0.15. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 or 0.1. The cation ratio may be 0. From the perspective of suppressing a decrease in stability and thermal stability of the glass during reheating and maintaining the high refractive index of the glass, the cation ratio is preferably within the above range.

[0138] In the optical glass of the first embodiment, La 3+ The content relative to La 3+ 、Gd 3+ and Y 3+ The total content of cation ratio [La 3+ / (La 3+ +Gd 3+ +Y 3+ 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, and 0.45. 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. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0139] In the optical glass of the first embodiment, Gd 3+ The content relative to La 3+ 、Gd 3+ and Y 3+ The total content of cation ratio [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. The lower limit of the cation ratio is preferably 0, and more preferably 0.01 and 0.05. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd and suppressing the decrease in the thermal stability of the glass, reducing the amount of Gd as a heavy rare earth 3+ From the viewpoint of the content of cations and the viewpoint of suppressing an increase in raw material costs, it is preferred that the cation ratio be within the above range.

[0140] In the optical glass of the first embodiment, Y 3+ The content relative to La 3+ 、Gd 3+ and Y 3+ The total 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. 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. 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 preferred that the cation ratio be within the above range.

[0141] In the optical glass of the first embodiment, Al 3+ The content relative to Si 4+ and B 3+ The total content of cations [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. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.05, 0.1, and 0.15. 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, impairing the thermal stability of the glass. From the perspective of maintaining the thermal stability of the glass, the cation ratio is preferably within the above range.

[0142] In the optical glass of the first embodiment, Al 3+ The content relative to Li + 、Na + and K + The total content of cations [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, respectively. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15, respectively. The cation ratio can 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, which can impair the thermal stability of the glass. From the perspective of maintaining the thermal stability of the glass, it is preferable to set the cation ratio within the above range.

[0143] In the optical glass of the first embodiment, Al 3+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content of cations [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. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15. 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, which can impair the thermal stability of the glass. From the perspective of maintaining the thermal stability and devitrification resistance of the glass, it is preferred that the cation ratio be within the above range.

[0144] In the optical glass of the first embodiment, Al 3+ The content relative to Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content of cations [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. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15. 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, which can impair the thermal stability of the glass. From the perspective of maintaining the thermal stability and devitrification resistance of the glass, it is preferred that the cation ratio be within the above range.

[0145] In the optical glass of the first embodiment, Al 3+ The content relative to La 3+ 、Gd3+ and Y 3+ The total content of cations [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, or 0.2, respectively. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, or 0.15, respectively. The cation ratio may be 0. From the perspective of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0146] In the optical glass of the first embodiment, Li + 、Na + and K + The total content relative to Si 4+ and B 3+ The total cation content ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.35, 0.3, 0.25, 0.24, 0.23, 0.22, and 0.21. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.07, 0.09, 0.10, 0.11, 0.12, 0.13, and 0.14. The cation ratio may be 0. From the perspective of improving the chemical durability, mechanical properties, and thermal stability of the glass, suppressing the decrease in stability during reheating, and obtaining an optical glass with a lowered glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0147] In the optical glass of the first embodiment, Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(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 0.9, 0.8, 0.7, 0.6, 0.5, 0.48, 0.46, 0.45, 0.44, 0.43, 0.42, 0.41, 0.40, and 0.39. 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, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, and 0.35. From the viewpoint of suppressing the reduction in chemical durability, mechanical properties, and thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0148] In the optical glass of the first embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(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, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, and 0.52. 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, 1.0, 0.9, 0.8, 0.7, 0.68, 0.66, 0.64, 0.62, 0.61, and 0.6. 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 preferred that the cation ratio be within the above range.

[0149] In the optical glass of the first embodiment, La 3+ 、Gd 3+ and Y 3+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(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, 0.55, 0.60, 0.65, 0.70, 0.72, 0.74, 0.76, 0.78, 0.80, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, 0.93, 0.94, and 0.95. 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, 1.4, 1.35, 1.3, 1.25, 1.2, 1.15, 1.13, 1.11, 1.10, and 1.09. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0150] In the optical glass of the first embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ 、La 3+ 、Gd 3+ and Y 3+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(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 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, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, and 1.55. The upper limit of the cation ratio is preferably 4, and more preferably 3, 2.5, 2.2, 2.0, 1.95, 1.90, 1.85, 1.80, 1.78, 1.76, 1.74, 1.72, 1.70, 1.68, 1.66, 1.64, and 1.62. From the viewpoint of obtaining an optical glass that suppresses volatilization of glass components during melting and exhibits excellent chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above-mentioned range.

[0151] In the optical glass of the first embodiment, Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(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 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 perspective of suppressing the decrease in the refractive index nd at the desired Abbe number vd, it is preferred that the cation ratio be within the above range.

[0152] In the optical glass of the first embodiment, Zr 4+ and Ta 5+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(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, respectively. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, and 0.04, respectively. The cation ratio may be 0. From the perspective of maintaining the thermal stability of the glass and suppressing the decrease in the refractive index nd at the desired Abbe number νd, it is preferred that the cation ratio be within the above range.

[0153] In the optical glass of the first embodiment, Li + 、Na + and K + The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total cation content ratio [(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, 0.5, 0.4, 0.35, 0.3, 0.25, 0.24, 0.23, 0.22, and 0.21. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.07, 0.09, 0.10, 0.11, 0.12, 0.13, and 0.14. The cation ratio may be 0. From the perspective of improving the chemical durability, mechanical properties, and thermal stability of the glass, suppressing the decrease in stability during reheating, and obtaining an optical glass with a lowered glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0154] In the optical glass of the first embodiment, Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total cation content ratio [(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 0.9, 0.8, 0.7, 0.6, 0.5, 0.48, 0.46, 0.45, 0.44, 0.43, 0.42, 0.41, 0.40, and 0.39. 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, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, and 0.35. From the viewpoint of suppressing the reduction in chemical durability, mechanical properties, and thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0155] In the optical glass of the first embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total cation content ratio [(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, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, and 0.52. 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, 1.0, 0.9, 0.8, 0.7, 0.68, 0.66, 0.64, 0.62, 0.61, and 0.6. 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 preferred that the cation ratio be within the above range.

[0156] In the optical glass of the first embodiment, La 3+ 、Gd 3+ and Y 3+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total cation content ratio [(La 3+ +Gd 3+ +Y 3+ ) / (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 0.10, 0.20, 0.30, 0.40, 0.50, 0.55, 0.60, 0.65, 0.70, 0.72, 0.74, 0.76, 0.78, 0.80, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, 0.93, 0.94, and 0.95. 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, 1.4, 1.35, 1.3, 1.25, 1.2, 1.15, 1.13, 1.11, 1.10, and 1.09. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0157] In the optical glass of the first embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ 、La 3+ 、Gd 3+ and Y 3+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total cation content ratio [(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 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, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, and 1.55. The upper limit of the cation ratio is preferably 4, and more preferably 3, 2.5, 2.2, 2.0, 1.95, 1.90, 1.85, 1.80, 1.78, 1.76, 1.74, 1.72, 1.70, 1.68, 1.66, 1.64, and 1.62. From the viewpoint of obtaining an optical glass that suppresses volatilization of glass components during melting and exhibits excellent chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above-mentioned range.

[0158] In the optical glass of the first embodiment, Li + 、Na + and K + The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6 + 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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, 0.5, 0.4, 0.35, 0.3, 0.25, 0.24, 0.23, 0.22, and 0.21. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.07, 0.09, 0.10, 0.11, 0.12, 0.13, and 0.14. The cation ratio may be 0. From the perspective of improving the chemical durability, mechanical properties, and thermal stability of the glass, suppressing the decrease in stability during reheating, and obtaining an optical glass with a lowered glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0159] In the optical glass of the first embodiment, Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 0.9, 0.8, 0.7, 0.6, 0.5, 0.48, 0.46, 0.45, 0.44, 0.43, 0.42, 0.41, 0.40, and 0.39. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, 0.15, 0.17, 0.19, 0.21, 0.23, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, and 0.35. From the viewpoint of suppressing the reduction in the chemical durability, mechanical properties, and thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0160] In the optical glass of the first embodiment, Li + 、Na + , K + Mg2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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, 0.46, 0.47, 0.48, 0.49, 0.50, 0.51, and 0.52. 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, 1.0, 0.9, 0.8, 0.7, 0.68, 0.66, 0.64, 0.62, 0.61, and 0.6. 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 preferred that the cation ratio be within the above range.

[0161] In the optical glass of the first embodiment, La 3+ 、Gd 3+ and Y 3+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(La 3+ +Gd 3+ +Y 3+ ) / (Si4+ +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 0.10, 0.20, 0.30, 0.40, 0.50, 0.55, 0.60, 0.65, 0.70, 0.72, 0.74, 0.76, 0.78, 0.80, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, 0.93, 0.94, and 0.95. 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, 1.4, 1.35, 1.3, 1.25, 1.2, 1.15, 1.13, 1.11, 1.10, and 1.09. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0162] In the optical glass of the first embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ 、La 3+ 、Gd 3+ and Y 3+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 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, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, and 1.55. The upper limit of the cation ratio is preferably 4, and more preferably 3, 2.5, 2.2, 2.0, 1.95, 1.90, 1.85, 1.80, 1.78, 1.76, 1.74, 1.72, 1.70, 1.68, 1.66, 1.64, and 1.62. From the viewpoint of obtaining an optical glass that suppresses volatilization of glass components during melting and exhibits excellent chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above-mentioned range.

[0163] In the optical glass of the first embodiment, Ti 4+ The content relative to Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content of cation ratio [Ti 4+ / (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, 0.4, 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. 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. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd while maintaining the desired Abbe number νd and the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0164] In the optical glass of the first embodiment, Nb 5+ The content relative to Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content of cation ratio [Nb 5+ / (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, 0.74, 0.73, 0.72, 0.71, 0.70, 0.69, 0.68, and 0.67. 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. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd, maintaining the desired Abbe number νd, and maintaining the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0165] In the optical glass of the first embodiment, W 6+ The content relative to Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total 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. 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. The cation ratio may be 0. From the perspective of increasing the relative partial dispersion Pg,F, maintaining the desired Abbe number νd, and maintaining the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0166] In the optical glass of the first embodiment, Bi 3+ The content relative to Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content of cation ratio [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, or 0.27. 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. The cation ratio is preferably within the above range from the viewpoints of increasing the refractive index nd and relative partial dispersion Pg,F, maintaining a desired Abbe number νd, maintaining the thermal stability of the glass, and reducing damage to platinum melting equipment.

[0167] In the optical glass of the first embodiment, Zr 4+ The content of Zr 4+ and Ta 5+ The total content of cation ratio [Zr 4+ / (Zr 4+ +Ta 5+ The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, or 0.85. The lower limit of the cation ratio is preferably 0, and more preferably 0.5, 0.6, 0.7, or 0.8. The cation ratio may be 0. From the perspective of maintaining the desired optical constants and suppressing raw material costs, it is preferred that the cation ratio be within the above range.

[0168] In the optical glass of the first embodiment, Ta 5+ The content of Zr 4+ and Ta 5+ The total content of cation ratio [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, or 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 perspective of maintaining the desired optical constants and suppressing raw material costs, it is preferred that the cation ratio be within the above range.

[0169] In the optical glass of the first embodiment, Ti 4+ The content relative to Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total content of cation ratio [Ti4+ / (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, 0.45, 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, 0.06. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd and maintaining the desired Abbe number νd, it is preferred that the cation ratio be within the above range.

[0170] In the optical glass of the first embodiment, Nb 5+ The content relative to Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total content of cation ratio [Nb 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 0.95, 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. 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. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd and maintaining the desired Abbe number νd, it is preferred that the cation ratio be within the above range.

[0171] In the optical glass of the first embodiment, Bi 3+ The content relative to Ti 4+ 、Nb 5+ 、Bi3+ 、W 6+ 、Zr 4+ and Ta 5+ The total content of cation ratio [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, or 0.11. 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. The cation ratio is preferably within the above range from the viewpoints of increasing the refractive index nd and relative partial dispersion Pg,F, maintaining a desired Abbe number νd, maintaining the thermal stability of the glass, and reducing damage to platinum melting equipment.

[0172] In the optical glass of the first embodiment, W 6+ The content relative to Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total 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. 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. The cation ratio may be 0. From the perspective of improving the relative partial dispersion Pg,F, maintaining the desired Abbe number νd, and maintaining the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0173] In the optical glass of the first embodiment, Zr 4+ The content relative to Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total content of cation ratio [Zr 4+ / (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 0.95, 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. 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. The cation ratio may be 0. From the perspective of increasing the refractive index nd while maintaining the desired Abbe number νd, and from the perspective of improving the mechanical properties and chemical durability of the glass, it is preferred that the cation ratio be within the above range.

[0174] In the optical glass of the first embodiment, Ta 5+ The content relative to Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total content of cation ratio [Ta 5+ / (Ti4+ +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, or 0.04. 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 perspective of maintaining a desired constant and suppressing raw material costs, it is preferred that the cation ratio be within the above range.

[0175] In the optical glass of the first embodiment, P 5+ The upper limit of the content of is preferably 30%, and more preferably 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, and 1%. 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 can be 0%. 5+ When the content of is within the above range, glass with high mechanical properties and chemical durability can be obtained.

[0176] In the optical glass of 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%. 3+ The lower limit of the content of Al is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5%, respectively. 3+ The content of Al can be 0%. 3+ In terms of the glass phase separation, it can be suppressed by adding an appropriate amount of Al. 3+ The content of Al improves the mechanical properties and chemical durability of the glass. 3+ If the content of Al is too high, the liquidus temperature rises, which impairs the thermal stability of the glass. If the liquidus temperature rises, the volatilization of glass components increases during the flow and molding of the glass, which causes the generation of striae. From the perspective of maintaining the thermal stability of the glass, it is preferred to add Al 3+ The content of is set within the above range.

[0177] In the optical glass of the first embodiment, Li + The upper limit of the content of Li is preferably 40%, and more preferably 30%, 20%, 17%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, and 8%. +The lower limit of the content of Li is preferably 0%, and more preferably 1%, 2%, 3%, 4%, 4.5%, 5%, 5.5%, 6%, and 6.5%. + The content of Li can be 0%. + It is a component that helps to lower the viscosity of glass. + If the content of Li is too high, there is a risk of reducing the thermal stability of the glass and the stability during reheating. + When the content of Li is too low, there is a risk of increasing the glass transition temperature Tg. + The content of is preferably within the above range.

[0178] In the optical glass of the first embodiment, Na + The upper limit of the content of Na is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5%. + The lower limit of the content of Na is preferably 0%, and more preferably 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, and 0.35%. + The content of can be 0%. + Similarly, Na + It is a component that helps to lower the viscosity of glass. + If the content of Na is too high, there is a risk of reducing the thermal stability of the glass and the stability during reheating. + The content of is preferably within the above range.

[0179] In the optical glass of 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%. + 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%. + The content of K can be 0%. + It has the effect of lowering the liquidus temperature and improving the thermal stability of the glass. + When the content of K is too high, chemical durability, weather resistance, and stability during reheating are reduced. + The content of is preferably within the above range.

[0180] In the optical glass of 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%. + The lower limit of the content of Rb is preferably 0%. + The content of Rb can be 0%. + When the content of Rb increases, the volatilization of glass components increases during melting, and the desired glass cannot be obtained. In addition, since Rb is an expensive component, + The content of is preferably within the above range.

[0181] In the optical glass of 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%. + The lower limit of the content is preferably 0%. Cs + The content of Cs can be 0%. + When the content of Cs increases, the volatilization of glass components increases during melting, and the desired glass cannot be obtained. In addition, there is a risk of reduced chemical durability and weather resistance. Therefore, Cs + The content of is preferably within the above range.

[0182] In the optical glass of the first embodiment, Mg 2+ The upper limit of the content of Mg is preferably 40%, and more preferably 30%, 20%, 15%, 13%, 11%, 10%, 9%, 8%, 7%, 6.5%, and 6%. 2+ The lower limit of the content of Mg is preferably 0%, and more preferably 1%, 2%, 3%, and 4%. 2+ The content of Mg can be 0%. 2+ If the content of Mg is too high, there is a risk that the thermal stability and devitrification resistance of the glass will be reduced. 2+ If the content of Mg is too low, there is a risk that the stability of the glass will be reduced during reheating. 2+ The content of is preferably within the above range.

[0183] In the optical glass of the first embodiment, Sr 2+ The upper limit of the content of Sr is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5%. 2+ The lower limit of the content of Sr is preferably 0%. 2+ The content of Sr can be 0%. 2+ It is a component in alkaline earth metals that increases the refractive index nd. 2+If the content of Sr is too high, there is a risk of reducing the thermal stability and devitrification resistance of the glass. 2+ The content of is preferably within the above range.

[0184] In the optical glass of the first embodiment, Ba 2+ The upper limit of the content of Ba is preferably 40%, and more preferably 30%, 25%, 20%, 18%, 16%, 15%, 14%, 13%, 12%, and 11%. 2+ The lower limit of the content of Ba is preferably 0%, and more preferably 1%, 2%, 3%, 4%, 5%, 6%, 7%, and 8%. 2+ Ba is a component that increases the refractive index nd among alkaline earth metals. It is also a component that lowers the liquidus temperature and improves the stability of glass by containing it in an appropriate amount. 2+ If the content of Ba is too high, there is a risk of reducing the thermal stability of the glass and the stability during reheating. 2+ If the content of Ba is too low, there is a risk of reducing the thermal stability of the glass and increasing the volatilization of the components of the glass during melting. 2+ The content of is preferably within the above range.

[0185] In the optical glass of 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%. 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%. 3+ , which can inhibit the volatilization of glass components and increase the refractive index nd. However, La 3+ When the content of La becomes too high, there is a risk that the thermal stability of the glass will decrease and the glass will easily become devitrified during production. 3+ The content of is preferably within the above range.

[0186] In the optical glass of 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%. 3+ The lower limit of the content of Gd is preferably 0%. 3+ The content of La can be 0%.3+ Similarly, by introducing a certain amount of Gd 3+ , thereby inhibiting the volatilization of glass components and increasing the refractive index nd. On the other hand, Gd 3+ When the content of Gd becomes too high, the thermal stability of the glass decreases. 3+ If the content of Gd becomes too high, the specific gravity of the glass increases, which is not preferable. In addition, there is a risk of increased raw material costs. Therefore, from the perspective of maintaining good thermal stability of the glass and suppressing the increase in specific gravity, as well as reducing the content of Gd as a heavy rare earth, the content of Gd is not too high. 3+ From the perspective of the content of Gd 3+ The content of is preferably within the above range.

[0187] In the optical glass of 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%. 3+ The lower limit of the content of is preferably 0%, and more preferably 1%, 5%, 8%, 10%, 12%, 14%, 16%, and 18%. 3+ The content can be 0%.

[0188] By importing a certain amount of Y 3+ , thereby inhibiting the volatilization of glass components and increasing the refractive index nd. However, Y 3+ When the content of Y becomes too high, the thermal stability of the glass decreases and the glass is easily devitrified during production. 3+ If the content of Y is too low, there is also a risk of reducing the thermal stability of the glass. Therefore, from the perspective of suppressing the reduction of the thermal stability of the glass, Y 3+ The content of is preferably within the above range.

[0189] In the optical glass of 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%. 3+ The lower limit of the content of Yb is preferably 0%. 3+ The content of La can be 0%. 3+ 、Gd 3+ 、Y 3+ In comparison, Yb 3+ Due to its high molecular weight, it increases the specific gravity of the glass. 3+When the content of Yb is too high, the thermal stability of the glass decreases. From the perspective of preventing the decrease in thermal stability of the glass and suppressing the increase in specific gravity, Yb 3+ The content of is preferably within the above range.

[0190] In the optical glass of the first embodiment, Ti 4+ The upper limit of the content of Ti is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5%. 4+ The lower limit of the content of Ti is preferably 0%, and may further 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 can be 0%. From the viewpoint of maintaining the desired Abbe number νd and improving the anomalous partial dispersion in the visible to near ultraviolet region, it is preferred to 4+ The content of is set within the above range.

[0191] In the optical glass of the first embodiment, Nb 5+ The upper limit of the content of Nb is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5%. 5+ The lower limit of the content of Nb is preferably 0%, and more preferably 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, and 1.6%. 5+ The content of Nb can be 0%. From the viewpoint of maintaining the desired Abbe number νd and improving the anomalous partial dispersion in the visible to near ultraviolet region, it is preferred to 5+ The content of is set within the above range.

[0192] In the optical glass of 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%. 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%. 6+ The content of W can be 0%. From the perspective of improving transmittance and reducing specific gravity, and maintaining the desired Abbe number νd and improving the anomalous partial dispersion in the visible to near ultraviolet region, it is preferred to 6+ The content of is set within the above range.

[0193] In the optical glass of 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%. 3+ The lower limit of the content of Bi is preferably 0%, and may further be 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4% or 1.6%. 3+ The content of Bi can be 0%. From the perspective of improving transmittance and reducing specific gravity, reducing damage to platinum manufacturing equipment, and improving the dispersion of abnormal parts in the visible to near-ultraviolet region, it is preferred to 3+ The content of is set within the above range.

[0194] In the optical glass of 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 this order. 5+ The lower limit of the content of Ta is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5%, respectively. 5+ The content of Ta can be 0%. 5+ It is a component that contributes to the high refractive index and low dispersion of glass. 5+ If the content of Ta is too high, there is a risk of increased raw material costs and a risk of reduced solubility of the glass. In addition, there is a risk of increased specific gravity. Therefore, Ta 5+ The content of is preferably within the above range.

[0195] In the optical glass of 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%. 4+ The lower limit of the content of Zr is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5%, respectively. 4+ The content of Zr can be 0%. 4+ However, Zr 4+ If the content of Zr is too high, there is a risk of the liquidus temperature LT rising and the solubility of the glass decreasing. 4+ The content of is set within the above range.

[0196] In the optical glass of the first embodiment, Sc 3+ The content of Sc is preferably 2% or less. 3+ The lower limit of the content is preferably 0%.

[0197] In the optical glass of the first embodiment, Hf 4+ The content of Hf is preferably 2% or less.4+ The lower limit of the content is preferably 0%.

[0198] Sc 3+ , Hf 4+ It has the function of improving the dispersion of glass, but it is an expensive component. 3+ , Hf 4+ The respective contents of are preferably within the above ranges.

[0199] In the optical glass of the first embodiment, Lu 3+ The content of Lu is preferably 2% or less. 3+ The lower limit of the content is preferably 0%.

[0200] Lu 3+ It has the effect of improving the dispersion of glass, but due to its large molecular weight, it is also a glass component that increases the specific gravity of the glass. 3+ The content of is preferably within the above range.

[0201] The optical glass of the first embodiment is preferably Si 4+ and B 3+ As an essential component, and 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+ The total content of these glass components is preferably 95% or more, more preferably 98% or more, further preferably 99% or more, and particularly preferably 99.5% or more.

[0202] The optical glass of the first embodiment includes O 2- As anionic component. 2-The upper limit of the content of is preferably 90 anion%, further 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%. In addition, O 2- The lower limit of the content is preferably 10 anion%, and further preferably 15 anion%, 20 anion%, 25 anion%, 30 anion%, 32 anion%, 34 anion%, 36 anion%, 38 anion%, 40 anion%, 42 anion%, 44 anion%, 45 anion%, 46 anion%, 47 anion%, 48 anion%, 49 anion%, 50 anion%, and 51 anion%.

[0203] The optical glass of the first embodiment may contain O 2- and F - Components other than O are considered as anionic components. 2- and F - Other anions include Cl - Br - , I - However, Cl - Br - , I - The volatilization of these components will cause the glass properties to change, the homogeneity of the glass to decrease, and the consumption of the melting equipment to become significant. - The content of Br is preferably less than 5% anion, more preferably less than 3% anion, further preferably less than 1% anion, particularly preferably less than 0.5% anion, further preferably less than 0.25% anion. - and I - The total content is preferably less than 5% anion, more preferably less than 3% anion, further preferably less than 1% anion, particularly preferably less than 0.5% anion, further preferably less than 0.1% anion, and further preferably 0% anion.

[0204] The optical glass of the first embodiment is preferably composed essentially of the above-mentioned glass components, but may contain other components within a range that does not impair the effects of the present invention.

[0205] In the optical glass of the first embodiment, Sb ions may be added from the viewpoint of suppressing a decrease in transmittance near a wavelength of 360 nm and near a wavelength of 375 nm. The upper limit of the Sb ion content is preferably 1.0000 mass %, 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 addition, the lower limit of the Sb ion content is preferably 0.0001 mass% in terms of the added ratio, and further more preferably 0.0005 mass%, 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%.

[0206] Sb ions can be added to the glass by, for example, Sb2O3 or Sb2S3. Sb ions include all Sb ions with trivalence, pentavalence and other valence numbers. In addition, the content of Sb ions is an added ratio. That is, the content of Sb ions when the total content of all glass components other than Sb ions is set to 100% by mass is expressed in mass%. From the viewpoint of suppressing the reduction of transmittance near a wavelength of 360nm and a wavelength of 375nm, it is preferred that the content of Sb ions be set to the above range. If the content of Sb ions is too much, Pt from the crucible is easily introduced into the glass, forming a Pt colloid and generating a Tyndall-like blur in the glass, which has the hidden danger of deteriorating the light transmittance that is not dependent on the wavelength range. Moreover, there is a hidden danger of deteriorating the light transmittance of a specific wavelength due to the light absorption of the Sb ions themselves. When no Sb ions are contained or the Sb ion content is too low, absorption by Pt ions near a wavelength of 360 nm becomes significant, resulting in a risk of deteriorating light transmittance at specific wavelengths extending into the visible light wavelength range.

[0207] Furthermore, the optical glass can achieve high transmittance across a wide range of the visible light region. To fully utilize this characteristic, it is preferably free of coloring elements. Examples of coloring elements include Cu, Co, Ni, Fe, Cr, Eu, Nd, Er, and V. The concentration of any of these elements is preferably less than 100 mass ppm, more preferably 0 to 80 mass ppm, even more preferably 0 to 50 mass ppm, and particularly preferably substantially absent.

[0208] Ga, Te, Tb, etc. are unnecessary components and are also expensive. Therefore, the content of Ga2O3, TeO2, and TbO2, expressed in mass %, is preferably in the range of 0 to 0.1%, more preferably 0 to 0.05%, further preferably 0 to 0.01%, further preferably 0 to 0.005%, still more preferably 0 to 0.001%, and particularly preferably substantially absent.

[0209] (Glass properties)

[0210] <Abbe number νd>

[0211] In the optical glass of the first embodiment, the Abbe number νd is preferably 37.5 to 78, and may be 40 to 75, 50 to 70, 55 to 67, 57 to 65, 58 to 64, 59 to 63, or 56 to 60.

[0212] The Abbe number νd can be set to a desired value by appropriately adjusting the content of each glass component. The component that relatively reduces the Abbe number, that is, 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+ wait.

[0213] In the present invention, the Abbe number νd and the relative partial dispersion Pg,F (hereinafter referred to as "relative partial dispersion") are calculated as follows. Specifically, the refractive index at the 12 wavelengths shown in Table A is measured using the Japanese Industrial Standard (JIS) JIS B 7071-1, Optical Glass - Determination of Refractive Index - Part 1: Minimum Deviation Angle Method. The refractive index for each line obtained from the measurements is then substituted into the SCHOTT dispersion equation specified in Appendix B to the Japanese Industrial Standard (JIS) JIS B 7071-1, Optical Glass - Determination of Refractive Index - Part 1: Minimum Deviation Angle Method, and the constants of the SCHOTT dispersion equation are determined using the least squares method. Using the SCHOTT dispersion equation with the determined constants, the Abbe number νd and the relative partial dispersion Pg,F (hereinafter referred to as "relative partial dispersion") are calculated from the obtained refractive index values ​​for each line.

[0214] [Table A]

[0215] Table A

[0216] Wavelength (nm) spectral lines light source 1013.98 T-ray (infrared mercury) Hg 852.11 S-rays (infrared cesium) Cs 706.52 r-rays (red helium) He 656.27 C rays (red hydrogen) H 643.85 C' rays (red cadmium) Cd 587.56 d-rays (yellow helium) He 546.07 e-rays (green mercury) Hg 486.13 F rays (blue hydrogen) H 479.99 F' rays (blue cadmium) Cd 435.84 g-rays (blue mercury) Hg 404.66 H-rays (purple mercury) Hg 365.01 I-ray (ultraviolet mercury) Hg

[0217] SCHOTT dispersion type: n 2 =a0+a1λ 2 +a2λ -2 +a3λ -4 +a4λ -6 +a5λ -8

[0218] Where n is the refractive index, λ is the wavelength (μm), and a0, a1, a2, a3, a4, and a5 are constants.

[0219] The Abbe number νd is expressed as follows using the refractive indices nd, nF, and nC under d-rays, F-rays, and C-rays, respectively.

[0220] νd=(nd-1) / (nF-nC)

[0221] <Refractive Index nd>

[0222] In the optical glass of the first embodiment, the refractive index nd is preferably 1.58 to 1.78, and may be 1.59 to 1.75, 1.60 to 1.72, 1.61 to 1.69, 1.62 to 1.68, 1.63 to 1.67, 1.64 to 1.66, or 1.67 to 1.69.

[0223] The refractive index nd can be set to a desired value by appropriately adjusting the content of each glass component. The component that has the effect of relatively increasing the refractive index nd (high refractive index component) is Nb 5+ 、Ti 4+ 、W 6+ 、Bi 3+ 、Zr4+ 、Ta 5+ 、La 3+ 、Gd 3+ 、Y 3+ On the other hand, the component that has the effect of relatively lowering the refractive index nd (refractive index lowering component) is Si 4+ 、B 3+ 、Li + 、Na + , K + wait.

[0224] In the optical glass of the first embodiment, the refractive index nd and the Abbe number νd preferably satisfy the following formula [1-1].

[0225] nd≥(-0.0081×νd+2.1181)···[1-1]

[0226] The refractive index nd and the Abbe number νd more preferably satisfy the following formula [1-2], and further more preferably satisfy the following formula [1-3], the following formula [1-4], and the following formula [1-5] in that order.

[0227] nd≥(-0.0081×νd+2.1231)···[1-2]

[0228] nd≥(-0.0081×νd+2.1281)···[1-3]

[0229] nd≥(-0.0081×νd+2.1331)···[1-4]

[0230] nd≥(-0.0081×νd+2.1381)···[1-5]

[0231] <Relative partial dispersion Pg,F>

[0232] In the optical glass of the first embodiment, the lower limit of the relative partial dispersion Pg,F in the short-wavelength region of visible light 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, respectively. By setting the relative partial dispersion Pg,F within the above ranges, an optical glass suitable for compensating for high-order chromatic aberrations can be obtained. Meanwhile, the upper limit of the relative partial dispersion Pg,F is not particularly limited, but is typically 0.5700, preferably 0.5650.

[0233] In the optical glass of the first embodiment, the relative partial dispersion Pg,F preferably satisfies the following formula [2-1].

[0234] Pg,F≥0.6200-0.0014×νd···[2-1]

[0235] The relative partial dispersion Pg,F more preferably satisfies the following formula [2-2], and further 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 this order.

[0236] Pg,F≥0.6220-0.0014×νd···[2-2]

[0237] Pg,F≥0.6240-0.0014×νd···[2-3]

[0238] Pg,F≥0.6260-0.0014×νd···[2-4]

[0239] Pg,F≥0.6270-0.0014×νd···[2-5]

[0240] Pg,F≥0.6280-0.0014×νd···[2-6]

[0241] In the optical element made of the optical glass of the first embodiment, from the viewpoint of satisfactorily compensating for chromatic aberration over a wide wavelength range, it is preferable that the relative partial dispersion Pg,F satisfies the above-mentioned formula.

[0242] In the optical glass of 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, 0.0150, 0.0140, 0.0130, 0.0120, 0.0110, or 0.0100. 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, and 0.0080, in that order. By setting ΔPg,F within the above range, an optical glass suitable for compensating for high-order chromatic aberration can be obtained.

[0243] The relative partial dispersion Pg,F is calculated using the above-mentioned SCHOTT dispersion formula.

[0244] In the present invention, the relative partial dispersion Pg,F is calculated by fitting the coefficients of the wavelength term of the refractive index-wavelength relationship equation known as the SCHOTT dispersion equation using the refractive index values ​​measured at the 12 different wavelengths (spectral lines) shown in Table A above. Once these coefficients are determined, the dispersion equation is used for calculation. Using the refractive index values ​​measured at 12 different wavelengths allows for the calculation of the relative partial dispersion Pg,F with high accuracy. Alternatively, a simplified method can be used to calculate the relative partial dispersion Pg,F by reducing the number of wavelengths used for refractive index measurement, but this method may yield insufficient accuracy.

[0245] The relative partial dispersion Pg,F is expressed as follows using the refractive indices ng, nF, and nC for g-rays, F-rays, and C-rays, respectively.

[0246] Pg,F=(ng-nF) / (nF-nC)

[0247] In a plane where the horizontal axis represents the Abbe number νd and the vertical axis represents the relative partial dispersion Pg,F, the normal line is expressed by the following equation.

[0248] Pg,F(0)=0.6483-(0.001802×νd)

[0249] Furthermore, the deviation ΔPg,F of the relative partial dispersion Pg,F from the normal line is expressed as follows.

[0250] ΔPg,F=Pg,F-Pg,F(0)

[0251] <Specific Gravity of Glass>

[0252] The specific gravity of the optical glass of 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 this order.

[0253] The component that relatively increases the specific gravity is Ba 2+ 、La 3+ 、Zr 4+ 、Nb 5+ 、Ta 5+ On the other hand, the component that relatively reduces the specific gravity is Si 4+ 、B 3+ 、Li + 、Na + Mg 2+ The specific gravity can be controlled by appropriately adjusting the contents of these components.

[0254] <Liquid phase temperature LT>

[0255] The upper limit of the liquidus temperature LT of the optical glass of the first embodiment is preferably 1200°C, and further 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. By setting the liquidus temperature to the above range, the melting and forming temperature of the glass can be lowered. As a result, the generation of ribs caused by the erosion of glass melting equipment (such as crucibles, stirring equipment for molten glass, etc.) in the melting process and the volatilization of the glass components themselves can be reduced. The lower limit of the liquidus temperature LT is not particularly limited. The liquidus temperature LT is determined by the balance of the contents of all glass components. Among them, for the liquidus temperature LT, Si 4+ 、B 3+ 、Li + 、Na + , K + The content of Zr has a great influence on the 4+ 、Al 3+ When the content of etc. is high, the liquidus temperature rises.

[0256] The liquidus temperature is determined as follows. 10cc (10ml) of glass is placed in a platinum crucible and melted at a temperature above 1200°C for 15 to 30 minutes. After cooling to below the glass transition temperature Tg, the glass and the platinum crucible are placed in a melting furnace at a given temperature and held for 2 hours. The temperature is set to an arbitrary temperature in 10°C increments, held for 2 hours, and then cooled. The presence of crystals inside the glass is observed using a 100x optical microscope. This operation is repeated at various temperatures, and the lowest temperature at which no crystallization occurs is defined as the liquidus temperature.

[0257] <Glass transition temperature Tg>

[0258] The upper limit of the glass transition temperature Tg of the optical glass of the first embodiment is preferably 625°C, and more preferably 620°C, 610°C, 600°C, 590°C, 580°C, 570°C, 560°C, 550°C, 540°C, 530°C, 520°C, 510°C, 500°C, 490°C, and 480°C. Furthermore, 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, 420°C, 430°C, 440°C, 450°C, 460°C, and 470°C. From the perspective of improving the yield during precision press molding, it is preferable to set the glass transition temperature Tg within the above range. On the other hand, if the glass transition temperature Tg is too high, there is a risk that precision press molding may not be possible.

[0259] The component that relatively lowers the glass transition temperature Tg is Li + 、Na+ , K + 、F - The component that relatively increases the glass transition temperature Tg is La 3+ 、Zr 4+ 、Nb 5+ The glass transition temperature Tg can be controlled by appropriately adjusting the contents of these components.

[0260] <Light Transmittance of Glass>

[0261] The light transmittance of the optical glass of the first embodiment can be evaluated by the coloration degrees λ80, λ70, and λ5.

[0262] For a glass sample with a thickness of 10.0 mm ± 0.1 mm, the spectral transmittance was measured in the wavelength range of 200 to 700 nm, and the wavelength at which the external transmittance reached 80% was set as λ80, the wavelength at which the external transmittance reached 70% was set as λ70, and the wavelength at which the external transmittance reached 5% was set as λ5.

[0263] The optical glass of the first embodiment preferably has a λ80 of 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.

[0264] <Chemical durability acid resistance Da>

[0265] In the optical glass of the first embodiment, the acid resistance Da is preferably level 5 or higher, more preferably level 4 or higher, and even more preferably level 3 or higher.

[0266] For acid resistance Da, a mass of powdered glass (particle size 425 to 600 μm) equivalent to the specific gravity was placed in a platinum cage and immersed in a quartz glass round-bottom flask containing 80 mL of a 0.01 mol / L nitric acid aqueous solution. The cage was treated for 60 minutes and evaluated by classification according to the grades in Table B based on the mass reduction rate (%).

[0267] [Table B]

[0268] Table B

[0269] grade Mass reduction (%) 1 Less than 0.20% 2 0.20% or more and less than 0.35% 3 0.35% or more and less than 0.65% 4 0.65% or more and less than 1.20% 5 1.20% or more and less than 2.20% 6 2.20% or more

[0270] <Chemical durability and water resistance Dw>

[0271] In the optical glass of the first embodiment, the water resistance Dw is preferably level 5 or higher, more preferably level 4 or higher, and even more preferably level 3 or higher.

[0272] Water resistance Dw was evaluated by placing a mass of powdered glass (particle size 425-600 μm) equivalent to the specific gravity into a platinum cage, immersing the cage in 80 mL of pure water (pH = 6.5-7.5) in a quartz glass round-bottom flask, and treating the cage in a boiling water bath for 60 minutes. The weight reduction (%) was then classified according to the grades in Table C for evaluation.

[0273] [Table C]

[0274] Table C

[0275] grade Mass reduction (%) 1 Less than 0.05% 2 0.05 or more and less than 0.10% 3 0.10 or more and less than 0.25% 4 0.25% or more and less than 0.60% 5 0.60% or more and less than 1.10% 6 1.10% or more

[0276] <Mechanical properties Knoop hardness Hk>

[0277] The lower limit of the Knoop hardness Hk of the optical glass of the first embodiment is preferably 400, and more preferably 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, and 520, respectively. The Knoop hardness Hk is preferably within the above range from the perspective of preventing damage during glass handling and during mechanical processing such as grinding and cutting to manufacture lenses. The upper limit of the Knoop hardness Hk is not particularly limited, but is generally 750, preferably 600.

[0278] Knoop hardness Hk can be adjusted by La 3+ 、Gd 3+ 、Y 3+ 、Si 4+ 、Zr 4+ 、Al 3+ content is increased.

[0279] <ΔT360>

[0280] In the optical glass of the first embodiment, when the thickness is 10.0 mm ± 0.1 mm, the upper limit of the difference between the external transmittance at a wavelength of 700 nm and the external transmittance at a wavelength of 360 nm (ΔT360) 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%. The lower limit of ΔT360 is not particularly limited, but is generally 2 to 30%. ΔT360 can be adjusted by introducing Sb ions. Furthermore, from the perspective of maintaining low dispersion, the use of high-dispersion components such as Ti, Nb, W, and Bi is not preferred. Incorporating these components for purposes such as achieving higher refractive index or higher anomalous dispersion increases ΔT360. By keeping ΔT360 within the above range, the decrease in transmittance around a wavelength of 360 nm can be suppressed.

[0281] <ΔT375>

[0282] In the optical glass of the first embodiment, when the thickness is set to 10.0 mm ± 0.1 mm, the upper limit of the difference between the external transmittance at a wavelength of 700 nm and the external transmittance at a wavelength of 375 nm (ΔT375) is preferably 15.0%, and more preferably 13.0%, 11.0%, 10.0%, 9.0%, 8.0%, 7.5%, 7.0%, 6.8%, 6.7%, 6.6%, 6.5%, 6.4%, 6.3%, 6.2%, 6.1%, and 6.0%. The lower limit of ΔT375 is not particularly limited, but is generally 2 to 15%. ΔT375 can be adjusted by introducing Sb ions. In addition, from the perspective of maintaining low dispersion, the use of high-dispersion components such as Ti, Nb, W, and Bi is not preferred. When these are introduced for the purpose of high refractive index or high anomalous dispersion, ΔT375 increases. By setting ΔT375 within the above range, a decrease in transmittance near a wavelength of 375 nm can be suppressed.

[0283] External transmittance is defined as the percentage of transmitted light intensity relative to incident light intensity when light is incident along the thickness of a glass sample [transmitted light intensity / incident light intensity × 100]. It should be noted that external transmittance also includes light reflection losses at the sample surface.

[0284] (Manufacture of optical glass)

[0285] The optical glass of the first embodiment is prepared by mixing glass raw materials in a manner to achieve the above-mentioned given composition, and then using the prepared glass raw materials to produce a glass according to a known glass manufacturing method. For example, a plurality of compounds are mixed and thoroughly mixed to produce a batch of raw materials, which are then placed in a platinum crucible for rough melting. The melt obtained by the rough melting is quenched and crushed to produce cullet. The cullet is further placed in a platinum crucible for heating and remelting to produce molten glass. After further clarification and homogenization, the molten glass is formed and slowly cooled to produce the optical glass. The forming and slow cooling of the molten glass can be carried out by known methods.

[0286] It should be noted that as long as the desired glass components can be introduced into the glass and the desired content can be achieved, there is no particular limitation on the compounds used in preparing the batch raw materials. Examples of such compounds include oxides, carbonates, nitrates, hydroxides, fluorides, composite oxides, fluorosilicates, fluoroborates, and the like.

[0287] (Manufacture of glass materials for press molding)

[0288] According to one embodiment of the present invention, there are provided a press-molding glass material made of the optical glass of the first embodiment and a method for producing the same.

[0289] Press-molding of a press-molding glass material can be performed by pressing the heated, softened press-molding glass material using a press-molding mold. Both heating and press-molding can be performed in the atmosphere. A powdered release agent, such as boron nitride, is evenly applied to the surface of the press-molding glass material. During heating and press-molding, this not only reliably prevents fusion between the glass and the mold, but also allows the glass to extend smoothly along the molding surface of the mold. Annealing after press-molding reduces strain within the glass, resulting in a homogeneous optical element blank.

[0290] Examples of press-molding glass materials include glass blocks having a mass equivalent to that of a target press-molded product, such as precision press-molding preforms and glass materials (press-molding glass gobs) for press-molding optical element blanks.

[0291] In addition, press-molded glass raw materials are also called preforms. In addition to raw materials provided for press molding in their original state, they also include raw materials provided for press molding through mechanical processing such as cutting, grinding, and polishing. As cutting methods, there are the following methods: forming a groove in the portion of the surface of the glass plate to be cut using a method called scribing, applying local pressure to the groove portion from the back of the grooved surface, and dividing the glass plate at the groove portion; cutting the glass plate with a cutter; etc. In addition, as grinding methods, spherical surface processing and smoothing processing using a curve generator can be listed. As grinding methods, grinding using abrasive grains such as cerium oxide and zirconium oxide can be listed.

[0292] The glass raw material for press molding of this embodiment is formed of optical glass with excellent mechanical properties, and is therefore not easily damaged during handling and processing. In the past, there was a problem in that damage to the surface of the glass raw material was easily left on the surface of the optical element after press molding, especially on the optical functional surface. The glass raw material for press molding of this embodiment has excellent mechanical properties and is not easily damaged on the surface of the glass raw material, and can therefore be preferably used as a glass raw material for precision press molding. In addition, even when the pressed product after press molding is subjected to mechanical processing, i.e., grinding or polishing to produce an optical element, it is possible to produce a pressed product that is not easily damaged by mechanical processing.

[0293] (Manufacturing of Optical Element Blanks)

[0294] According to one embodiment of the present invention, an optical element blank formed from the optical glass of the first embodiment can be provided. The optical element blank is a glass molded body having a shape that is similar to the shape of the optical element to be manufactured. The optical element blank can be manufactured by a method such as molding glass into a shape that increases the machining allowance removed when machining into the shape of the optical element to be manufactured. For example, the optical element blank can be manufactured by a method of heating and softening a glass raw material for press molding and press molding (reheat pressing method), or by supplying a molten glass block to a press molding mold and press molding using a known method (direct pressing method).

[0295] (Manufacturing of optical components)

[0296] Known methods can be applied to the production of optical elements using the optical glass of the first embodiment. For example, the above-mentioned optical element blank can be used for production. In addition, for example, in the production of the above-mentioned optical glass, a glass raw material formed by the optical glass of the present invention is produced by pouring molten glass into a casting mold and forming it into a plate shape. The obtained glass raw 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 press molded (reheat pressed) by a known method to produce an optical element blank of a shape similar to that of the optical element. The optical element can be produced by a method including a process of processing the optical element blank. As processing, cutting, cutting, rough grinding, fine grinding, grinding, etc. can be exemplified. When performing such processing, by using the above-mentioned glass, breakage can be reduced, and high-quality optical elements can be stably supplied.

[0297] Examples of optical element types include spherical lenses, aspherical lenses, prisms, and diffraction gratings. Examples of lens shapes include biconvex lenses, plano-convex lenses, biconcave lenses, plano-concave lenses, convex meniscus lenses, and concave meniscus lenses. The optically functional surfaces of optical elements may also be coated with anti-reflection films, total reflection films, and the like, depending on their intended use.

[0298] The optical element of this embodiment is formed from optical glass with excellent mechanical properties and is therefore less susceptible to damage during handling and processing. This is particularly true when the optical element is being fixed. For example, during lens centering, even when the lens surface is clamped from both sides, it is not susceptible to damage.

[0299] Second embodiment

[0300] In the optical glass of the second embodiment,

[0301] Si 4+ The content of cations is greater than 0% and less than 30%.

[0302] B 3+ The content of cations is greater than 0% and less than 50.00%.

[0303] F - The content of anions is 10% or more,

[0304] Ca 2+ The content of cationic ions is less than 25%,

[0305] Zn 2+ The content of cationic ions is less than 13%,

[0306] Ge 4+ The content of cationic ions is less than 5%,

[0307] La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 27 cation % or more,

[0308] Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ] is 3.5 cation % or more,

[0309] 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 3.5 cation % or more,

[0310] Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is 0.070 or more,

[0311] La 3+ 、Gd 3+ 、Y 3+ 、Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+、B 3 + 、P 5+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 0.83 or more,

[0312] Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content [Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ] is greater than 0 cation %.

[0313] In the optical glass of the second embodiment, Si 4+ The content of Si is greater than 0% and less than 30%. 4+ The lower limit of the content of Si is preferably 1%, and more preferably 1.5%, 2%, 2.5%, 3%, 3.5%, and 4%. 4+ The upper limit of the content is preferably 25%, and more preferably 23%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, and 7%.

[0314] Si 4+ It is a network forming component of glass. 4+When the content of Si is within the above range, an optical glass having abnormal partial dispersion, improved chemical durability, mechanical properties and thermal stability can be obtained. 4+ If the content of Si is too low, there is a risk that the chemical durability, mechanical properties and thermal stability of the glass will be reduced. 4+ If the content of MgO is too high, the solubility of the glass may be reduced, and the refractive index nd may be reduced. In addition, the thermal stability of the glass may be reduced, and the glass transition temperature Tg may be increased.

[0315] In the optical glass of the second embodiment, B 3+ The content of B is greater than 0% and less than 50.00%. 3+ The lower limit of the content of is preferably 5%, and more preferably 10%, 15%, 17%, 19%, 21%, 23%, 25%, 27%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, and 36%. 3+ The upper limit of the content is preferably 45.00%, and more preferably 44.00%, 43.00%, 42.50%, 42.00%, 41.50%, 41.00%, 40.50%, and 40.00%, in this order.

[0316] B 3+ It is a network forming component of glass. 3+ The chemical durability can be improved by setting the content of B in the above range. 3+ If the content of B is too low, there is a risk of reducing the thermal stability and mechanical properties of the glass. 3+ When the content of is too high, there is a risk that the volatilization of glass components increases, and there is a risk that the thermal stability and chemical durability of the glass decrease.

[0317] The optical glass of the second embodiment includes F - As anionic component. - The content of anion is 10% or more. - The lower limit of the content of is preferably 15 anion%, and further preferably 17 anion%, 19 anion%, 21 anion%, 23 anion%, 24 anion%, 25 anion%, 26 anion%, 27 anion%, 28 anion%, 29 anion%, 30 anion%, 31 anion%. In addition, F -The upper limit of the content of is preferably 80 anion%, and further more preferably 75 anion%, 70 anion%, 65 anion%, 63 anion%, 61 anion%, 59 anion%, 57 anion%, 55 anion%, 53 anion%, 51 anion%, 49 anion%, 47 anion%, 45 anion%, 43 anion%, 41 anion%, 40 anion%, 39 anion%, 38 anion%, 37 anion%, 36 anion%, 35 anion%. By adding F - By setting the content of F in the above range, an optical glass having high refractive index, high thermal stability, abnormal partial dispersion, low glass transition temperature Tg, and suitable for precision press molding can be obtained despite having low dispersion. - If the content of F is too low, there is a risk that the thermal stability of the glass will be reduced, and there is a risk that the abnormal partial dispersion property cannot be obtained. - When the content is too high, there is a risk of increased volatilization of glass components.

[0318] In the optical glass of the second embodiment, Ca 2+ The content of Ca is less than 25%. 2+ The upper limit of the content of Ca is preferably 20%, and more preferably 15%, 10%, 9%, 8%, 7%, 6%, and 5%. 2+ The lower limit of the content of Ca is preferably 0%, and more preferably 0.5%, 1%, and 2% in that order. 2+ The content can be 0%.

[0319] By adding Ca 2+ When the content of Ca is within the above range, an optical glass having desired optical constants can be obtained. 2+ When the content of MgO is too high, the thermal stability of the glass is impaired, and there is a risk that the glass transition temperature Tg and the liquidus temperature TL may increase.

[0320] In the optical glass of the second embodiment, Zn 2+ The content of Zn is less than 13%. 2+ The upper limit of the content of Zn is preferably 10%, and more preferably 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 can be 0%.

[0321] Zn 2+ It is a glass component that has the effect of lowering the glass transition temperature Tg by introduction. 2+ When the content of Zn is within the above range, an optical glass having an improved glass transition temperature Tg can be obtained.2+ When the content of is too high, there is a risk that the specific gravity increases, and there is a risk that the thermal stability and chemical durability of the glass decrease. In addition, the Abbe number increases, and as a result, there is a risk that the desired high refractive index characteristics cannot be obtained.

[0322] In the optical glass of the second embodiment, Ge 4+ The content of Ge is less than 5%. 4+ The upper limit of the content of Ge is preferably 4.5%, and more preferably 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, and 0.5%. 4+ The lower limit of the content of Ge is preferably 0%. 4+ The content can be 0%.

[0323] Ge 4+ It has the function of improving the dispersion of glass and is an especially expensive component among the commonly used glass components. 4+ Setting the content of MgO within the above range can reduce the manufacturing cost of the glass.

[0324] In the optical glass of the second embodiment, La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 27% or more. The lower limit of the total content is preferably 31%, and further preferably 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, and 44%. In addition, the upper limit of the total content is preferably 60%, and further more preferably 58%, 56%, 55%, 54%, 53%, 52%, 51%, 50%, 49%, and 48%. By setting 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, there is a risk that the desired optical constants cannot be obtained. If the total content is too high, there is a risk that the thermal stability of the glass is reduced.

[0325] In the optical glass of the second embodiment, Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2 +] is 3.5% or more. The lower limit of the total content is preferably 3.6%, and more preferably 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, and 4.5%. In addition, the upper limit of the total content is preferably 30%, and more preferably 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, and 8%. By setting the total content within the above range, an optical glass having desired optical constants, reduced volatilization of glass components, and high thermal stability of the glass can be obtained. On the other hand, if the total content is too low, there is a risk that the volatilization of glass components increases, and the thermal stability and devitrification resistance of the glass decrease. On the other hand, when the total content is too large, there is a possibility that the high refractive index may be impaired, and there is a possibility that the thermal stability of the glass may be impaired.

[0326] In the optical glass of the second embodiment, 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 3.5% or more. The lower limit of the total content is preferably 3.6%, and more preferably 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, and 4.5%. In addition, the upper limit of the total content is preferably 40%, and more preferably 39%, 38%, 37%, 36%, 35%, 34%, 33%, 32%, 31%, 30%, 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, and 8%. By setting the total content within the above range, an optical glass having desired optical constants, a lower glass transition temperature Tg, reduced volatilization of glass components, and high thermal stability can be obtained.

[0327] In the optical glass of the second embodiment, Si4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is 0.070 or more. The lower limit of the cation ratio is preferably 0.08, and more preferably 0.09, 0.10, 0.11, or 0.12. In addition, the upper limit of the cation ratio is preferably 0.80, and more preferably 0.70, 0.60, 0.50, 0.40, 0.35, 0.30, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, or 0.20. By setting the cation ratio within the above range, an optical glass with improved chemical durability, mechanical properties, and thermal stability can be obtained.

[0328] In the optical glass of the second embodiment, La 3+ 、Gd 3+ 、Y 3+ 、Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、P 5+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 0.83 or more. The lower limit of the cation ratio is preferably 0.85, and more preferably 0.87, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, and 1.00. In addition, the upper limit of the cation ratio is preferably 5.00, and more preferably 4.00, 3.00, 2.50, 2.30, 2.10, 2.00, 1.90, 1.85, 1.80, 1.75, 1.70, 1.65, 1.60, 1.55, 1.50, 1.45, 1.40, 1.35, 1.30, 1.25, 1.20, 1.15, and 1.10. 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 low, there is a risk that the volatilization of glass components will increase, while if the cation ratio is too high, there is a risk that the thermal stability of the glass will decrease.

[0329] In the optical glass of the second embodiment, Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content [Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ] is greater than 0%. The lower limit of the total content is preferably 0.1%, and more preferably 0.5%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, and 1.5%. In addition, the upper limit of the total content is preferably 20%, and more preferably 18%, 16%, 14%, 12%, 10%, 8%, 6%, 5%, 4%, 3.5%, 3.0%, and 2.5%. By setting the total content within the above range, the refractive index can be increased, the desired Abbe number νd can be maintained, and the anomalous partial dispersion in the visible to near-ultraviolet region can be improved.

[0330] Hereinafter, non-limiting examples are shown regarding the contents and ratios of glass components other than those described above in the optical glass of the second embodiment.

[0331] In the optical glass of the second embodiment, Si 4+ and B 3+ The total content [Si 4+ +B 3+The lower limit of the total content is preferably 10%, and more preferably 15%, 20%, 22%, 24%, 26%, 28%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, and 43%. In addition, the upper limit of the total content is preferably 70%, and more preferably 65%, 60%, 59%, 58%, 57%, 56%, 55%, 54%, 53%, 52%, 51%, 50%, 49%, 48%, 47%, 46%, and 45%. From the viewpoint of obtaining an optical glass having desired optical constants and anomalous partial dispersion, improved chemical durability, mechanical properties, and thermal stability, and suppressed volatilization of glass components during melting, the total content is preferably within the above range.

[0332] In the optical glass of the second embodiment, Li + 、Na + and K + The total content [Li + +Na + +K + The lower limit of the total content is preferably 0%, and more preferably 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, and 0.6%. In addition, the upper limit of the total content is preferably 50%, and more preferably 45%, 40%, 35%, 30%, 25%, 20%, 18%, 16%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, and 2%. The total content may be 0%. From the perspective of lowering the liquidus temperature of the glass and lowering the glass transition temperature Tg, and from the perspective of maintaining the thermal stability of the glass, the total content is preferably within the above range.

[0333] In the optical glass of the second embodiment, Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+The upper limit of the total content is preferably 30%, and more preferably 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, and 8%. The lower limit of the total content is preferably 3.5%, and more preferably 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, and 4.5%. If the total content is too high, there is a risk of impairing the high refractive index and the thermal stability of the glass. On the other hand, if the total content is too low, there is a risk of increased volatilization of glass components, reduced thermal stability, devitrification resistance, and stability during reheating of the glass. Therefore, the total content is preferably within the above range.

[0334] In the optical glass of the second embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content [Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The lower limit of the total content is preferably 3.5%, and more preferably 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, and 4.5%. In addition, the upper limit of the total content is preferably 50%, and more preferably 45%, 40%, 35%, 32%, 30%, 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, and 6%. From the viewpoint of obtaining an optical glass having desired optical constants, lowering the glass transition temperature Tg and the liquidus temperature of the glass, and reducing the volatilization of the glass components during melting, it is preferable to set the total content within the above range.

[0335] In the optical glass of the second embodiment, Zr 4+ and Ta 5+ The total content [Zr 4+ +Ta 5+The upper limit of the total content is preferably 20%, and more preferably 15%, 10%, 9%, 8%, 7%, 6%, 5%, and 4%. In addition, the lower limit of the total content is preferably 0%, and more preferably 0.5%, 1.0%, 1.5%, 2.0%, and 2.5%. From the perspective of maintaining high refractive index and low dispersion, the total content may be 0%. In addition, from the perspective of maintaining the thermal stability of the glass, it is preferable to set the total content within the above range. If the total content is too high, there is a risk of reduced thermal stability of the glass and increased raw material costs.

[0336] In the optical glass of the second embodiment, Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total content [Ti 4+ +Nb 5+ +Bi 3+ +W 6+ +Zr 4+ +Ta 5+ The upper limit of the total content is preferably 20%, and more preferably 18%, 16%, 14%, 12%, 10%, 9%, 8%, 7%, and 6%. In addition, the upper limit of the total content is preferably 0%, and more preferably 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, and 4.0%. From the perspective of maintaining high refractive index and low dispersion, the total content may be 0%. In addition, from the perspective of maintaining the desired Abbe number νd and improving the anomalous partial dispersion in the visible to near-ultraviolet region, it is preferred that the total content be within the above range.

[0337] In the optical glass of the second embodiment, B 3+ The content relative to Si 4+ and B 3+ The total content of cation ratio [B 3 + / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 0.98, and more preferably 0.97, 0.96, 0.95, 0.94, 0.93, 0.92, 0.91, 0.90, 0.89, and 0.88, respectively. Furthermore, the lower limit of the cation ratio is preferably 0.20, and more preferably 0.30, 0.40, 0.50, 0.60, 0.65, 0.67, 0.69, 0.71, 0.73, 0.75, 0.77, 0.79, and 0.80, respectively. From the perspective of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above range.

[0338] In the optical glass of the second embodiment, Si 4+ 、B 3+ and P 5+ The total content [Si 4+ +B 3+ +P 5+ The lower limit of the total content is preferably 10%, and more preferably 15%, 20%, 22%, 24%, 26%, 28%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, and 43%. In addition, the upper limit of the total content is preferably 70%, and more preferably 65%, 60%, 58%, 56%, 54%, 52%, 50%, 48%, 47%, 46%, and 45%. From the viewpoint of obtaining an optical glass having desired optical constants and anomalous partial dispersion, improved chemical durability, mechanical properties, and thermal stability, and suppressed volatilization of glass components during melting, the total content is preferably within the above range.

[0339] In the optical glass of the second embodiment, Si 4+ The content relative to Si 4+ 、B 3+ and P 5+ The total content of cations is [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, 0.30, 0.29, 0.28, 0.27, 0.26, 0.25, 0.24, 0.23, 0.22, 0.21, and 0.20. In addition, the lower limit of the cation ratio is preferably 0.070, and more preferably 0.08, 0.09, 0.10, 0.11, and 0.12. From the viewpoint of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above range.

[0340] In the optical glass of the second embodiment, B 3+ The content relative to Si 4+ 、B 3+ and P 5+ The total content of cation ratio [B 3+ / (Si 4+ +B 3+ +P 5+The upper limit of the cation ratio is preferably 0.98, and more preferably 0.97, 0.96, 0.95, 0.94, 0.93, 0.92, 0.91, 0.90, 0.89, and 0.88, respectively. Furthermore, the lower limit of the cation ratio is preferably 0.20, and more preferably 0.30, 0.40, 0.50, 0.60, 0.65, 0.67, 0.69, 0.71, 0.73, 0.75, 0.77, 0.79, and 0.80, respectively. From the perspective of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above range.

[0341] In the optical glass of the second embodiment, P 5+ The content relative to Si 4+ 、B 3+ and P 5+ The total 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. Furthermore, the lower limit of the cation ratio is preferably 0, and more preferably 0.005, 0.01, and 0.015. The cation ratio may be 0. From the perspective of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above range.

[0342] In the optical glass of the second embodiment, Li + The content relative to Li + 、Na + and K + The total cation content ratio [Li + / (Li + +Na + +K + The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, or 0.85. In addition, 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, or 0.7. The cation ratio may be 1. From the perspective of suppressing a decrease in stability during reheating and lowering the glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0343] In the optical glass of the second embodiment, Na + The content relative to Li + 、Na + and K + The total cation 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, or 0.3 in that order. Furthermore, the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, or 0.15 in that order. The cation ratio may be 0. From the perspective of suppressing a decrease in stability during reheating and lowering the glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0344] In the optical glass of the second embodiment, K + The content relative to Li + 、Na + and K + The total content of cation ratio [K + / (Li + +Na + +K + The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, or 0.3 in that order. Furthermore, the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, or 0.15 in that order. The cation ratio may be 0. From the perspective of suppressing a decrease in stability during reheating and lowering the glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0345] In the optical glass of the second embodiment, Mg 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total cation content ratio [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, 0.5, 0.45, and 0.4. 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, and 0.3. The cation ratio may be 0. From the viewpoint of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0346] In the optical glass of the second embodiment, Ca 2+ The content relative to Mg 2+ , Ca2+ 、Sr 2+ And Ba 2+ The total cation content ratio [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, or 0.15. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 or 0.1. The cation ratio may be 0. From the perspective of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0347] In the optical glass of the second embodiment, Sr 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content of cation ratio [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, or 0.15. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 or 0.1. The cation ratio may be 0. From the perspective of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0348] In the optical glass of the second embodiment, Ba 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content of cation ratio [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, 0.50, 0.55, and 0.60. 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, and 0.70. From the viewpoint of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0349] In the optical glass of the second embodiment, Mg 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ The total cation content ratio [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, 0.5, 0.45, and 0.4. 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, and 0.3. The cation ratio may be 0. From the viewpoint of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0350] In the optical glass of the second embodiment, Ca 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ The total cation content ratio [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, or 0.15. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 or 0.1. The cation ratio may be 0. From the perspective of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0351] In the optical glass of the second embodiment, Sr 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ The total content of cation ratio [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, or 0.15. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 or 0.1. The cation ratio may be 0. From the perspective of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0352] In the optical glass of the second embodiment, Ba 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ The total content of cation ratio [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 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, and 0.60. 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, and 0.70. The cation ratio may be 0. From the viewpoint of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0353] In the optical glass of the second embodiment, Zn 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ The total content of cation ratio [Zn 2+ / (Mg 2+ +Ca 2+ +Sr2+ +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, or 0.15. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 or 0.1. The cation ratio may be 0. From the perspective of suppressing a decrease in stability and thermal stability of the glass during reheating and maintaining the high refractive index of the glass, the cation ratio is preferably within the above range.

[0354] In the optical glass of the second embodiment, La 3+ The content relative to La 3+ 、Gd 3+ and Y 3+ The total content of cation ratio [La 3+ / (La 3+ +Gd 3+ +Y 3+ 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, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.62, 0.64, 0.66, and 0.68. The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.78, 0.76, 0.74, and 0.72. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0355] In the optical glass of the second embodiment, Gd 3+ The content relative to La 3+ 、Gd 3+ and Y 3+ The total content of cation ratio [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, 0.48, 0.46, 0.44, 0.42, 0.40, 0.38, 0.36, 0.34, and 0.32. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.05, 0.10, 0.15, 0.20, 0.22, 0.24, 0.26, and 0.28. 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 preferred that the cation ratio be within the above range.

[0356] In the optical glass of the second embodiment, Y 3+ The content relative to La 3+ 、Gd 3+ and Y 3+ The total 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, 0.60, 0.55, 0.50, 0.45, 0.40, 0.35, 0.30, 0.25, 0.20, 0.15, 0.10, and 0.05. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, and 0.03. The cation ratio may be 0. From the perspective of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0357] In the optical glass of the second embodiment, Ti 4+ The content relative to Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content of cation ratio [Ti 4+ / (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, 0.4, 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. 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. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd while maintaining the desired Abbe number νd and the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0358] In the optical glass of the second embodiment, Nb 5+ The content relative to Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content of cation ratio [Nb 5+ / (Ti 4+ +Nb5+ +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, 0.74, 0.73, 0.72, 0.71, 0.70, 0.69, 0.68, and 0.67. 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. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd, maintaining the desired Abbe number νd, and maintaining the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0359] In the optical glass of the second embodiment, W 6+ The content relative to Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total 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. 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. The cation ratio may be 0. From the perspective of increasing the relative partial dispersion Pg,F, maintaining the desired Abbe number νd, and maintaining the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0360] In the optical glass of the second embodiment, Bi 3+ The content relative to Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content of cation ratio [Bi 3+ / (Ti 4+ +Nb 5+ +W 6+ +Bi3+ 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, or 0.27. 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. The cation ratio is preferably within the above range from the viewpoints of increasing the refractive index nd and relative partial dispersion Pg,F, maintaining a desired Abbe number νd, maintaining the thermal stability of the glass, and reducing damage to platinum melting equipment.

[0361] In the optical glass of the second embodiment, Zr 4+ The content of Zr 4+ and Ta 5+ The total content of cation ratio [Zr 4+ / (Zr 4+ +Ta 5+ The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, or 0.85. The lower limit of the cation ratio is preferably 0, and more preferably 0.5, 0.6, 0.7, or 0.8. The cation ratio may be 0. From the perspective of maintaining the desired optical constants and suppressing raw material costs, it is preferred that the cation ratio be within the above range.

[0362] In the optical glass of the second embodiment, Ta 5+ The content of Zr 4+ and Ta 5+ The total content of cation ratio [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, or 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 perspective of maintaining the desired optical constants and suppressing raw material costs, it is preferred that the cation ratio be within the above range.

[0363] In the optical glass of the second embodiment, Ti 4+ The content relative to Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+The total content of cation ratio [Ti 4+ / (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, 0.45, 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, 0.06. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd and maintaining the desired Abbe number νd, it is preferred that the cation ratio be within the above range.

[0364] In the optical glass of the second embodiment, Nb 5+ The content relative to Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total content of cation ratio [Nb 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 0.95, 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. 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. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd and maintaining the desired Abbe number νd, it is preferred that the cation ratio be within the above range.

[0365] In the optical glass of the second embodiment, Bi 3+ The content relative to Ti 4+ 、Nb 5+、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total content of cation ratio [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, or 0.11. 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. The cation ratio is preferably within the above range from the viewpoints of increasing the refractive index nd and relative partial dispersion Pg,F, maintaining a desired Abbe number νd, maintaining the thermal stability of the glass, and reducing damage to platinum melting equipment.

[0366] In the optical glass of the second embodiment, W 6+ The content relative to Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total 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. 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. The cation ratio may be 0. From the perspective of improving the relative partial dispersion Pg,F, maintaining the desired Abbe number νd, and maintaining the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0367] In the optical glass of the second embodiment, Zr 4+ The content relative to Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total content of cation ratio [Zr 4+ / (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 0.95, 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. 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. The cation ratio may be 0. From the perspective of increasing the refractive index nd while maintaining the desired Abbe number νd, and from the perspective of improving the mechanical properties and chemical durability of the glass, it is preferred that the cation ratio be within the above range.

[0368] In the optical glass of the second embodiment, Ta 5+ The content relative to Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total content of cation ratio [Ta 5+ / (Ti4+ +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, or 0.04. 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 perspective of maintaining a desired constant and suppressing raw material costs, it is preferred that the cation ratio be within the above range.

[0369] In the optical glass of the second embodiment, Al 3+ The content relative to Si 4+ and B 3+ The total content of cations [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. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.05, 0.1, and 0.15. 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, impairing the thermal stability of the glass. From the perspective of maintaining the thermal stability of the glass, the cation ratio is preferably within the above range.

[0370] In the optical glass of the second embodiment, Al 3+ The content relative to Li + 、Na + and K + The total content of cations [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, respectively. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15, respectively. The cation ratio can 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, which can impair the thermal stability of the glass. From the perspective of maintaining the thermal stability of the glass, it is preferable to set the cation ratio within the above range.

[0371] In the optical glass of the second embodiment, Al 3+The content relative to Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content of cations [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. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15. 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, which can impair the thermal stability of the glass. From the perspective of maintaining the thermal stability and devitrification resistance of the glass, it is preferred that the cation ratio be within the above range.

[0372] In the optical glass of the second embodiment, Al 3+ The content relative to Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content of cations [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. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, and 0.15. 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, which can impair the thermal stability of the glass. From the perspective of maintaining the thermal stability and devitrification resistance of the glass, it is preferred that the cation ratio be within the above range.

[0373] In the optical glass of the second embodiment, Al 3+ The content relative to La 3+ 、Gd 3+ and Y 3+ The total content of cations [Al3+ / (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, or 0.2, respectively. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.1, or 0.15, respectively. The cation ratio may be 0. From the perspective of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0374] Li in the optical glass of the second embodiment + 、Na + and K + The total content, relative to Si 4+ and B 3+ The total cation content ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.09, 0.08, 0.07, and 0.06. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04, and 0.05. The cation ratio may be 0. From the perspective of improving the chemical durability, mechanical properties, and thermal stability of the glass, suppressing the decrease in stability during reheating, and obtaining an optical glass with a lowered glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0375] In the optical glass of the second embodiment, Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(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 0.9, 0.8, 0.7, 0.6, 0.5, 0.48, 0.46, 0.44, 0.42, 0.40, 0.38, 0.36, 0.34, 0.32, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, and 0.12. The lower limit of the cation ratio is preferably 0.01, and more preferably 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, and 0.10. From the viewpoint of suppressing the reduction in chemical durability, mechanical properties, and thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0376] In the optical glass of the second embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(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 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, and 0.10. 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, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.48, 0.46, 0.44, 0.42, 0.40, 0.38, 0.36, 0.34, 0.32, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, and 0.12. 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, the cation ratio is preferably within the above-mentioned range.

[0377] In the optical glass of the second embodiment, La 3+ 、Gd 3+ and Y 3+ The total content relative to Si4+ and B 3+ The total cation content ratio [(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, 0.55, 0.60, 0.65, 0.70, 0.72, 0.74, 0.76, 0.78, 0.80, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, 0.93, 0.94, and 0.95. 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, 1.4, 1.35, 1.3, 1.25, 1.2, 1.15, 1.13, 1.11, 1.10, and 1.09. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0378] In the optical glass of the second embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ 、La 3+ 、Gd 3+ and Y 3+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(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 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, 1.05, 1.10, 1.13, and 1.15. The upper limit of the cation ratio is preferably 4, and more preferably 3, 2.5, 2.2, 2.0, 1.95, 1.90, 1.85, 1.80, 1.75, 1.70, 1.65, 1.60, 1.55, 1.50, 1.45, 1.40, 1.35, 1.30, 1.25, and 1.20. From the viewpoint of obtaining an optical glass having excellent chemical durability, mechanical properties, and thermal stability while suppressing volatilization of glass components during melting, it is preferred that the cation ratio be within the above range.

[0379] In the optical glass of the second embodiment, Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(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 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 perspective of suppressing the decrease in the refractive index nd in the desired Abbe number νd, it is preferred that the cation ratio be within the above range.

[0380] In the optical glass of the second embodiment, Zr 4+ and Ta 5+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(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, respectively. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, and 0.04, respectively. The cation ratio may be 0. From the perspective of maintaining the thermal stability of the glass and suppressing the decrease in the refractive index nd at the desired Abbe number νd, it is preferred that the cation ratio be within the above range.

[0381] In the optical glass of the second embodiment, Li + 、Na + and K + The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total cation content ratio [(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, 0.5, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.09, 0.08, 0.07, and 0.06. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04, and 0.05. The cation ratio may be 0. From the perspective of improving the chemical durability, mechanical properties, and thermal stability of the glass, suppressing the decrease in stability during reheating, and obtaining an optical glass with a lowered glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0382] In the optical glass of the second embodiment, Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total cation content ratio [(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 0.9, 0.8, 0.7, 0.6, 0.5, 0.48, 0.46, 0.44, 0.42, 0.40, 0.38, 0.36, 0.34, 0.32, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, and 0.12. The lower limit of the cation ratio is preferably 0.01, and more preferably 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, and 0.10. From the viewpoint of suppressing the reduction in chemical durability, mechanical properties, and thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0383] In the optical glass of the second embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total cation content ratio [(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 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, and 0.10. 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, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.48, 0.46, 0.44, 0.42, 0.40, 0.38, 0.36, 0.34, 0.32, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, and 0.12. 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, the cation ratio is preferably within the above-mentioned range.

[0384] In the optical glass of the second embodiment, La 3+ 、Gd 3+ and Y 3+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total cation content ratio [(La 3+ +Gd 3+ +Y 3+ ) / (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 0.10, 0.20, 0.30, 0.40, 0.50, 0.55, 0.60, 0.65, 0.70, 0.72, 0.74, 0.76, 0.78, 0.80, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, 0.93, 0.94, and 0.95. 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, 1.4, 1.35, 1.3, 1.25, 1.2, 1.15, 1.13, 1.11, 1.10, 1.09, 1.08, 1.07, 1.06, and 1.05. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferable to set the cation ratio to the above range.

[0385] In the optical glass of the second embodiment, Li +、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ 、La 3+ 、Gd 3+ and Y 3+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total cation content ratio [(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 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, and 1.08. The upper limit of the cation ratio is preferably 4, and more preferably 3, 2.5, 2.2, 2.0, 1.95, 1.90, 1.85, 1.80, 1.75, 1.70, 1.65, 1.60, 1.55, 1.50, 1.45, 1.40, 1.35, 1.30, 1.25, 1.20, and 1.15. From the viewpoint of obtaining an optical glass that suppresses volatilization of glass components during melting and has excellent chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above range.

[0386] In the optical glass of the second embodiment, Li + 、Na + and K + The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6 + 、Bi 3+ 、Zr4+ and Ta 5+ The total cation content ratio [(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, 0.5, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.09, 0.08, 0.07, and 0.06. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04, and 0.05. The cation ratio may be 0. From the perspective of improving the chemical durability, mechanical properties, and thermal stability of the glass, suppressing the decrease in stability during reheating, and obtaining an optical glass with a lowered glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0387] In the optical glass of the second embodiment, Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 0.9, 0.8, 0.7, 0.6, 0.5, 0.48, 0.46, 0.44, 0.42, 0.40, 0.38, 0.36, 0.34, 0.32, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, and 0.12. The lower limit of the cation ratio is preferably 0.01, and more preferably 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, and 0.09. From the viewpoint of suppressing the reduction in chemical durability, mechanical properties, and thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0388] In the optical glass of the second embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, and 0.09. 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, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.48, 0.46, 0.44, 0.42, 0.40, 0.38, 0.36, 0.34, 0.32, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, and 0.12. 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, the cation ratio is preferably within the above-mentioned range.

[0389] In the optical glass of the second embodiment, La 3+ 、Gd 3+ and Y 3+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+)] has a lower limit of preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.55, 0.60, 0.65, 0.70, 0.72, 0.74, 0.76, 0.78, 0.80, 0.82, 0.84, 0.86, 0.88, 0.90, 0.92, and 0.93, respectively. 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, 1.4, 1.35, 1.3, 1.25, 1.2, 1.15, 1.13, 1.11, 1.10, 1.09, 1.08, 1.07, 1.06, 1.05, 1.04, 1.03, 1.02, 1.01, 1.00, 0.99, 0.98, 0.97, 0.96, and 0.95. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0390] In the optical glass of the second embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ 、La 3+ 、Gd 3+ and Y 3+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 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, 0.92, 0.94, 0.96, 0.98, and 1.00. The upper limit of the cation ratio is preferably 4, and more preferably 3, 2.5, 2.2, 2.0, 1.95, 1.90, 1.85, 1.80, 1.75, 1.70, 1.65, 1.60, 1.55, 1.50, 1.45, 1.40, 1.35, 1.30, 1.25, 1.20, 1.15, 1.13, 1.11, 1.10, 1.09, 1.08, 1.07, and 1.06. From the viewpoint of obtaining an optical glass that suppresses volatilization of glass components during melting and exhibits excellent chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above-mentioned range.

[0391] In the optical glass of the second embodiment, P 5+ The upper limit of the content of is preferably 30%, and more preferably 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, and 1%. 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 can be 0%. 5+ When the content of is within the above range, glass with high mechanical properties and chemical durability can be obtained.

[0392] In the optical glass of the second 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%. 3+ The lower limit of the content of Al is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5%, respectively. 3+ The content of Al can be 0%. 3+ In terms of the glass phase separation, it can be suppressed by adding an appropriate amount of Al. 3+ The content of Al improves the mechanical properties and chemical durability of the glass. 3+ If the content of Al is too high, the liquidus temperature rises, which impairs the thermal stability of the glass. If the liquidus temperature rises, the volatilization of glass components increases during the flow and molding of the glass, which causes the generation of striae. From the perspective of maintaining the thermal stability of the glass, it is preferred to add Al 3+ The content of is set within the above range.

[0393] In the optical glass of the second embodiment, Li +The upper limit of the content of Li is preferably 40%, and more preferably 30%, 20%, 17%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, and 2%. + The lower limit of the content of Li is preferably 0%, and more preferably 0.01%, 0.05%, 0.1%, 0.5%, and 1%. + The content of Li can be 0%. + It is a component that helps to lower the viscosity of glass. + If the content of Li is too high, there is a risk of reducing the thermal stability of the glass and the stability during reheating. + When the content of Li is too low, there is a risk of increasing the glass transition temperature Tg. + The content of is preferably within the above range.

[0394] In the optical glass of the second embodiment, Na + The upper limit of the content of Na is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5%. + The lower limit of the content of Na is preferably 0%, and more preferably 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, and 0.35%. + The content of can be 0%. + Similarly, Na + It is a component that helps to lower the viscosity of glass. + If the content of Na is too high, there is a risk of reducing the thermal stability of the glass and the stability during reheating. + The content of is preferably within the above range.

[0395] In the optical glass of the second 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%. + 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%. + The content of K can be 0%. + It has the effect of lowering the liquidus temperature and improving the thermal stability of the glass. + When the content of K is too high, chemical durability, weather resistance, and stability during reheating are reduced. + The content of is preferably within the above range.

[0396] In the optical glass of the second 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%. + The lower limit of the content of Rb is preferably 0%. + The content of Rb can be 0%. + When the content of Rb increases, the volatilization of glass components increases during melting, and the desired glass cannot be obtained. In addition, since Rb is an expensive component, + The content of is preferably within the above range.

[0397] In the optical glass of the second 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%. + The lower limit of the content of Cs is preferably 0%. + The content of Cs can be 0%. + When the content of Cs increases, the volatilization of glass components increases during melting, and the desired glass cannot be obtained. In addition, there is a risk of reducing chemical durability and weather resistance. Therefore, Cs + The content of is preferably within the above range.

[0398] In the optical glass of the second embodiment, Mg 2+ The upper limit of the content of Mg is preferably 40%, and more preferably 30%, 20%, 15%, 13%, 11%, 10%, 9%, 8%, 7%, 6.5%, and 6%. 2+ The lower limit of the content of Mg is preferably 0%, and more preferably 1%, 2%, 3%, and 4%. 2+ The content of Mg can be 0%. 2+ If the content of Mg is too high, there is a risk that the thermal stability and devitrification resistance of the glass will be reduced. 2+ If the content of Mg is too low, there is a risk that the stability of the glass will be reduced during reheating. 2+ The content of is preferably within the above range.

[0399] In the optical glass of the second embodiment, Sr 2+ The upper limit of the content of Sr is preferably 40%, and more preferably 30%, 20%, 10%, 8%, 6%, 5%, 4%, 3%, 2%, 1%, and 0.5%. 2+ The lower limit of the content of Sr is preferably 0%. 2+ The content of Sr can be 0%. 2+It is a component in alkaline earth metals that increases the refractive index nd. 2+ If the content of Sr is too high, there is a risk of reducing the thermal stability and devitrification resistance of the glass. 2+ The content of is preferably within the above range.

[0400] In the optical glass of the second embodiment, Ba 2+ The upper limit of the content of Ba is preferably 40%, and more preferably 30%, 25%, 20%, 18%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, and 6%. 2+ The lower limit of the content of Ba is preferably 0%, and more preferably 1%, 2%, 3%, and 4% in this order. 2+ Ba is a component that increases the refractive index nd among alkaline earth metals. It is also a component that lowers the liquidus temperature and improves the stability of glass by containing it in an appropriate amount. 2+ If the content of Ba is too high, there is a risk of reducing the thermal stability of the glass and the stability during reheating. 2+ If the content of Ba is too low, there is a risk of lowering the thermal stability of the glass and increasing the volatilization of the components of the glass during melting. 2+ The content of is preferably within the above range.

[0401] In the optical glass of the second 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%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, and 31%. 3+ The upper limit of the content of La is preferably 50%, and more preferably 49%, 48%, 47%, 46%, 45%, 44%, 43%, 42%, 41%, 40%, 39%, 38%, 37%, 36%, 35%, and 34%. 3+ , thereby inhibiting the volatilization of glass components and increasing the refractive index nd. However, La 3+ When the content of La becomes too high, there is a risk that the thermal stability of the glass will decrease and the glass will easily become devitrified during production. 3+ The content of is preferably within the above range.

[0402] In the optical glass of the second embodiment, Gd 3+The upper limit of the content of Gd is preferably 50%, and more preferably 45%, 40%, 35%, 30%, 28%, 26%, 24%, 22%, 20%, 18%, 16%, and 15%. 3+ The lower limit of the content of La is preferably 0%, and more preferably 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, and 12%. 3+ Similarly, by introducing a certain amount of Gd 3+ , thereby inhibiting the volatilization of glass components, maintaining the thermal stability of the glass, and increasing the refractive index nd. On the other hand, Gd 3+ When the content of Gd becomes too much, the thermal stability of the glass decreases. 3+ If the content of Gd becomes too much, the specific gravity of the glass increases, which is not preferred. In addition, there is a hidden danger of increased raw material costs. Therefore, from the perspective of maintaining good thermal stability of the glass and suppressing the increase in specific gravity, Gd 3+ The content of is preferably within the above range.

[0403] In the optical glass of the second 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%, 24%, 22%, 20%, 18%, 16%, 14%, 12%, 10%, 8%, 6%, 5%, 4%, 3%, and 2%. In addition, Y 3+ The lower limit of the content of is preferably 0%, and more preferably 0.01%, 0.05%, 0.1%, 0.5%, and 1%. 3+ The content can be 0%.

[0404] By importing a certain amount of Y 3+ , can inhibit the volatilization of glass components and increase the refractive index nd. However, Y 3+ When the content of Y becomes too much, the thermal stability of the glass decreases and the glass is easily devitrified during production. 3+ La, which is also a rare earth 3+ 、Gd 3+ In comparison, the effect of increasing the refractive index nd is small. On the other hand, Y 3+ If the content of Y is too low, there is also a risk of reducing the thermal stability of the glass. Therefore, from the perspective of suppressing the reduction of the thermal stability of the glass, Y 3+ The content of is preferably within the above range.

[0405] In the optical glass of the second 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%. 3+ The lower limit of the content of Yb is preferably 0%. 3+ The content of La can be 0%. 3+ 、Gd 3+ 、Y 3+ In comparison, Yb 3+ The molecular weight of Yb is large, so it will increase the specific gravity of the glass. 3+ When the content of Yb is too high, the thermal stability of the glass decreases. From the perspective of preventing the decrease in thermal stability of the glass and suppressing the increase in specific gravity, Yb 3+ The content of is preferably within the above range.

[0406] In the optical glass of the second embodiment, Ti 4+ The upper limit of the content of Ti is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5%. 4+ The lower limit of the content of Ti is preferably 0%, and can further be 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4% or 1.6%. From the viewpoint of maintaining the desired Abbe number νd and improving the anomalous partial dispersion in the visible to near ultraviolet region, it is preferred to 4+ The content of is set within the above range.

[0407] In the optical glass of the second embodiment, Nb 5+ The upper limit of the content of Nb is preferably 20%, and more preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5%. 5+ The lower limit of the content of Nb is preferably 0%, and further preferably 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, and 1.6%. From the perspective of maintaining the desired Abbe number νd and improving the anomalous partial dispersion in the visible to near ultraviolet region, it is preferred to reduce Nb to 0%. 5+ The content of is set within the above range.

[0408] In the optical glass of the second 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%. 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%. From the perspective of improving transmittance and reducing specific gravity, and from the perspective of maintaining the desired Abbe number νd and improving the anomalous partial dispersion in the visible to near ultraviolet region, it is preferred to 6+ The content of is set within the above range.

[0409] In the optical glass of the second 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%. 3+ The lower limit of the content of Bi is preferably 0%, and may further be 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4% or 1.6%. 3+ The content of Bi can be 0%. From the perspective of improving transmittance and reducing specific gravity, reducing damage to platinum manufacturing equipment, and improving the dispersion of abnormal parts in the visible to near-ultraviolet region, it is preferred to 3+ The content of is set within the above range.

[0410] In the optical glass of the second 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 this order. 5+ The lower limit of the content of Ta is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5%, respectively. 5+ The content of Ta can be 0%. 5+ It is a component that contributes to the high refractive index and low dispersion of glass. 5+ If the content of Ta is too high, there is a risk of increased raw material costs and a risk of reduced solubility of the glass. In addition, there is a risk of increased specific gravity. Therefore, Ta 5+ The content of is preferably within the above range.

[0411] In the optical glass of the second embodiment, Zr 4+ The upper limit of the content of Zr is preferably 10%, and more preferably 9%, 8%, 7%, 6%, 5%, and 4%. 4+ The lower limit of the content of Zr is preferably 0%, and more preferably 0.05%, 0.1%, 0.5%, 1.0%, 1.5%, and 2.0%. 4+ The content of Zr can be 0%. 4+ However, Zr 4+If the content of Zr is too high, there is a risk of the liquidus temperature LT rising and the solubility of the glass decreasing. 4+ The content of is set within the above range.

[0412] In the optical glass of the second embodiment, Sc 3+ The content of Sc is preferably 2% or less. 3+ The lower limit of the content is preferably 0%.

[0413] In the optical glass of the second embodiment, Hf 4+ The content of Hf is preferably 2% or less. 4+ The lower limit of the content is preferably 0%.

[0414] Sc 3+ , Hf 4+ It has the function of improving the dispersion of glass and is an expensive component. 3+ , Hf 4+ The respective contents of are preferably within the above ranges.

[0415] In the optical glass of the second embodiment, Lu 3+ The content of Lu is preferably 2% or less. 3+ The lower limit of the content is preferably 0%.

[0416] Lu 3+ It has the effect of improving the dispersion of glass, but due to its large molecular weight, it is also a glass component that increases the specific gravity of the glass. 3+ The content of is preferably within the above range.

[0417] The optical glass of the second embodiment is preferably Si 4+ and B 3+ As an essential component, and 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+The total content of these glass components is preferably 95% or more, more preferably 98% or more, further preferably 99% or more, and particularly preferably 99.5% or more.

[0418] The optical glass of the second embodiment includes O 2- As anionic component. 2- The upper limit of the content of is preferably 90 anion%, and further preferably 88 anion%, 86 anion%, 84 anion%, 82 anion%, 80 anion%, 78 anion%, 76 anion%, 75 anion%, 74 anion%, 73 anion%, 72 anion%, 71 anion%, 70 anion%, 69 anion%, and 68 anion%. In addition, O 2- The lower limit of the content is preferably 10 anion%, and further preferably 15 anion%, 20 anion%, 25 anion%, 30 anion%, 35 anion%, 40 anion%, 45 anion%, 50 anion%, 55 anion%, 60 anion%, 61 anion%, 62 anion%, 63 anion%, 64 anion%, and 65 anion%.

[0419] The optical glass of the second embodiment may contain O 2- and F - Components other than O are considered as anionic components. 2- and F - Other anions include Cl - Br - , I - However, Cl - Br - , I - The volatilization of these components will cause the glass properties to change, the homogeneity of the glass to decrease, and the consumption of the melting equipment to become significant. - The content of Br is preferably less than 5% anion, more preferably less than 3% anion, further preferably less than 1% anion, particularly preferably less than 0.5% anion, further preferably less than 0.25% anion. - and I - The total content is preferably less than 5% anion, more preferably less than 3% anion, further preferably less than 1% anion, particularly preferably less than 0.5% anion, further preferably less than 0.1% anion, further preferably 0% anion.

[0420] The optical glass of the second embodiment is preferably composed essentially of the above-mentioned glass components, but may contain other components within a range that does not impair the effects of the present invention.

[0421] In the optical glass of the second embodiment, Sb ions may be added from the viewpoint of suppressing a decrease in transmittance near a wavelength of 360 nm and near a wavelength of 375 nm. The upper limit of the Sb ion content is preferably 1.0000 mass %, 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 addition, the lower limit of the Sb ion content is preferably 0.0001 mass% in terms of the added ratio, and further more preferably 0.0005 mass%, 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%.

[0422] Sb ions can be added to the glass by, for example, Sb2O3 or Sb2S3. Sb ions include all Sb ions with trivalence, pentavalence, and other valence numbers. In addition, the content of Sb ions is an added ratio. That is, the content of Sb ions is expressed in mass % when the total content of all glass components other than Sb ions is set to 100 mass %. From the viewpoint of suppressing the reduction of the transmittance near a wavelength of 360nm and a wavelength of 375nm, it is preferred that the content of Sb ions be set to the above range. If the content of Sb ions is too much, Pt from the crucible is easily introduced into the glass, forming a Pt colloid and generating a Tyndall-like blur in the glass, which has the hidden danger of deteriorating the light transmittance that is not dependent on the wavelength range. Moreover, there is a hidden danger of deteriorating the light transmittance of a specific wavelength due to the light absorption of the Sb ions themselves. When no Sb ions are contained or the Sb ion content is too low, absorption by Pt ions near a wavelength of 360 nm becomes significant, resulting in a risk of deteriorating light transmittance at specific wavelengths extending into the visible light wavelength range.

[0423] Furthermore, the optical glass can achieve high transmittance across a wide range of the visible light region. To fully utilize this characteristic, it is preferably free of coloring elements. Examples of coloring elements include Cu, Co, Ni, Fe, Cr, Eu, Nd, Er, and V. The concentration of any of these elements is preferably less than 100 mass ppm, more preferably 0 to 80 mass ppm, even more preferably 0 to 50 mass ppm, and particularly preferably substantially absent.

[0424] Ga, Te, Tb, etc. are unnecessary components and are also expensive. Therefore, 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%, further preferably 0 to 0.01%, further preferably 0 to 0.005%, further preferably 0 to 0.001%, and particularly preferably substantially not contained.

[0425] (Glass properties)

[0426] <Abbe number νd>

[0427] In the optical glass of the second embodiment, the Abbe number νd is preferably 37.5 to 60, and may be 40 to 58, 45 to 56, 47 to 54, 48 to 52, 49 to 51, or 55 to 59, 56 to 58. The Abbe number νd can be calculated and adjusted in the same manner as in the first embodiment.

[0428] <Refractive Index nd>

[0429] In the optical glass of the second embodiment, the refractive index nd is preferably 1.60 to 1.92, and may be 1.65 to 1.87, 1.70 to 1.82, 1.75 to 1.80, 1.76 to 1.79, or 1.65 to 1.68. The refractive index nd can be calculated and adjusted in the same manner as in the first embodiment.

[0430] In the optical glass of the second embodiment, the refractive index nd and the Abbe number νd preferably satisfy the following formula [3-1].

[0431] nd≥(-0.0081×νd+2.1181)···[3-1]

[0432] The refractive index nd and the Abbe number νd more preferably satisfy the following formula [3-2], and further more preferably satisfy the following formula [3-3], the following formula [3-4], and the following formula [3-5] in this order.

[0433] nd≥(-0.0081×νd+2.1231)···[3-2]

[0434] nd≥(-0.0081×νd+2.1281)···[3-3]

[0435] nd≥(-0.0081×νd+2.1331)···[3-4]

[0436] nd≥(-0.0081×νd+2.1381)···[3-5]

[0437] <Relative partial dispersion Pg,F>

[0438] In the optical glass of the second embodiment, the lower limit of the relative partial dispersion Pg,F in the short-wavelength region of visible light is preferably 0.5200, and more preferably 0.5250, 0.5300, 0.5350, 0.5400, 0.5450, 0.5500, 0.5510, 0.5520, 0.5530, 0.5540, and 0.5550, respectively. By setting the relative partial dispersion Pg,F within the above ranges, an optical glass suitable for compensating for high-order chromatic aberrations can be obtained. Meanwhile, the upper limit of the relative partial dispersion Pg,F is not particularly limited, but is typically 0.5700, preferably 0.5650. The relative partial dispersion Pg,F can be calculated in the same manner as in the first embodiment.

[0439] In the optical glass of the second embodiment, the relative partial dispersion Pg,F preferably satisfies the following formula [4-1].

[0440] Pg,F≥0.6200-0.0014×νd···[4-1]

[0441] The relative partial dispersion Pg,F more preferably satisfies the following formula [4-2], and further more preferably satisfies the following formula [4-3], the following formula [4-4], the following formula [4-5], and the following formula [4-6] in this order.

[0442] Pg,F≥0.6220-0.0014×νd···[4-2]

[0443] Pg,F≥0.6230-0.0014×νd···[4-3]

[0444] Pg,F≥0.6240-0.0014×νd···[4-4]

[0445] Pg,F≥0.6250-0.0014×νd···[4-5]

[0446] Pg,F≥0.6260-0.0014×νd···[4-6]

[0447] In the optical element made of the optical glass of the second embodiment, from the viewpoint of satisfactorily compensating for chromatic aberration in a wide wavelength range, it is preferable that the relative partial dispersion Pg,F satisfies the above-mentioned formula.

[0448] In the optical glass of the second 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, 0.0150, 0.0140, 0.0130, 0.0120, 0.0110, and 0.0100. On the other hand, the lower limit of ΔPg,F is preferably -0.0100, and further preferably -0.0090, -0.0080, -0.0070, -0.0060, -0.0050, -0.0040, -0.0030, -0.0020, -0.0010, -0.0005, and 0.0000. By setting ΔPg,F within the above range, an optical glass suitable for compensating for high-order chromatic aberration can be obtained. ΔPg,F can be calculated in the same manner as in the first embodiment.

[0449] <Specific Gravity of Glass>

[0450] The specific gravity of the optical glass of the second embodiment is preferably 6.0 or less, and more preferably 5.9 or less, 5.8 or less, 5.7 or less, 5.6 or less, and 5.5 or less, in this order.

[0451] The component that relatively increases the specific gravity is Ba 2+ 、La 3+ 、Zr 4+ 、Nb 5+ 、Ta 5+ On the other hand, the relatively low specific gravity component is Si 4+ 、B 3+ 、Li + 、Na + Mg 2+ The specific gravity can be controlled by appropriately adjusting the contents of these components.

[0452] <Liquid phase temperature LT>

[0453] The upper limit of the liquidus temperature LT of the optical glass of the second embodiment is preferably 1200°C, and more preferably 1190°C, 1180°C, 1170°C, 1160°C, 1150°C, 1140°C, 1130°C, and 1120°C, respectively. By setting the liquidus temperature to the above range, the melting and forming temperature of the glass can be lowered. As a result, the generation of ribs caused by the erosion of glass melting equipment (such as crucibles, stirring equipment for molten glass, etc.) in the melting process and the volatilization of the glass components themselves can be reduced. The lower limit of the liquidus temperature LT is not particularly limited. The liquidus temperature LT is determined by the balance of the contents of all glass components. Among them, for the liquidus temperature LT, Si 4+ 、B 3+ 、Li + 、Na+ , K + The content of Zr has a great influence on the 4+ 、Al 3+ When the content of the like is high, the liquidus temperature rises. The liquidus temperature LT is determined in the same manner as in the first embodiment.

[0454] <Glass transition temperature Tg>

[0455] The upper limit of the glass transition temperature Tg of the optical glass of the second embodiment is preferably 625°C, and more preferably 620°C, 615°C, 610°C, 595°C, 590°C, 585°C, and 580°C. Furthermore, 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, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, and 500°C. From the perspective of improving the yield during precision press molding, it is preferable to set the glass transition temperature Tg within the above range. On the other hand, if the glass transition temperature Tg is too high, there is a risk that precision press molding may not be possible.

[0456] The component that relatively lowers the glass transition temperature Tg is Li + 、Na + , K + 、F - The component that relatively increases the glass transition temperature Tg is La 3+ 、Zr 4+ 、Nb 5+ The glass transition temperature Tg can be controlled by appropriately adjusting the contents of these components.

[0457] <Light Transmittance of Glass>

[0458] The light transmittance of the optical glass of the second embodiment can be evaluated by the coloration degrees λ80, λ70, and λ5.

[0459] For a glass sample with a thickness of 10.0 mm ± 0.1 mm, the spectral transmittance was measured in the wavelength range of 200 to 700 nm, and the wavelength at which the external transmittance reached 80% was set as λ80, the wavelength at which the external transmittance reached 70% was set as λ70, and the wavelength at which the external transmittance reached 5% was set as λ5.

[0460] The optical glass of the second embodiment preferably has a λ80 of 450 nm or less, more preferably 400 nm or less, and even more preferably 380 nm or less. The λ70 is preferably 430 nm or less, more preferably 380 nm or less, and even more preferably 360 nm or less. The λ5 is preferably 380 nm or less, more preferably 330 nm or less, and even more preferably 320 nm or less.

[0461] <Chemical durability acid resistance Da>

[0462] In the optical glass of the second embodiment, the acid resistance Da is preferably level 5 or higher, more preferably level 4 or higher, and further preferably level 3 or higher. The acid resistance Da can be evaluated in the same manner as in the first embodiment.

[0463] <Chemical durability and water resistance Dw>

[0464] In the optical glass of the second embodiment, the water resistance Dw is preferably at least level 5, more preferably at least level 4, and even more preferably at least level 3. The water resistance Dw can be evaluated in the same manner as in the first embodiment.

[0465] <Mechanical properties Knoop hardness Hk>

[0466] The lower limit of the Knoop hardness Hk of the optical glass of the second embodiment is preferably 400, and more preferably 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, and 550, respectively. The Knoop hardness Hk is preferably within the above range from the perspective of preventing damage during glass handling and during mechanical processing such as grinding and cutting to manufacture lenses. The upper limit of the Knoop hardness Hk is not particularly limited, but is generally 750, preferably 600.

[0467] Knoop hardness Hk can be adjusted by La 3+ 、Gd 3+ 、Y 3+ 、Si 4+ 、Zr 4+ 、Al 3+ content is increased.

[0468] <ΔT360>

[0469] In the optical glass of the second embodiment, when the thickness is 10.0 mm ± 0.1 mm, the upper limit of the difference between the external transmittance at a wavelength of 700 nm and the external transmittance at a wavelength of 360 nm (ΔT360) is preferably 30.0%, and more preferably 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%. The lower limit of ΔT360 is not particularly limited, but is generally 3 to 30%. ΔT360 can be adjusted by introducing Sb ions. Furthermore, from the perspective of maintaining low dispersion, the use of high-dispersion components such as Ti, Nb, W, and Bi is not preferred. Incorporating these components for purposes such as achieving higher refractive index or higher anomalous dispersion increases ΔT360. By setting ΔT360 within the above range, the decrease in transmittance around a wavelength of 360 nm can be suppressed.

[0470] <ΔT375>

[0471] In the optical glass of the second embodiment, when the thickness is set to 10.0 mm ± 0.1 mm, the upper limit of the difference between the external transmittance at a wavelength of 700 nm and the external transmittance at a wavelength of 375 nm (ΔT375) is preferably 15.0%, and more preferably 13.0%, 11.0%, 10.0%, 9.0%, 8.0%, 7.5%, 7.0%, 6.8%, 6.7%, 6.6%, 6.5%, 6.4%, 6.3%, 6.2%, 6.1%, and 6.0%. The lower limit of ΔT375 is not particularly limited, but is generally 2 to 15%. ΔT375 can be adjusted by introducing Sb ions. In addition, from the perspective of maintaining low dispersion, the use of high-dispersion components such as Ti, Nb, W, and Bi is not preferred. When these are introduced for the purpose of high refractive index or high anomalous dispersion, ΔT375 increases. By setting ΔT375 within the above range, a decrease in transmittance near a wavelength of 375 nm can be suppressed.

[0472] External transmittance is defined as the percentage of transmitted light intensity relative to incident light intensity when light is incident along the thickness of a glass sample [transmitted light intensity / incident light intensity × 100]. It should be noted that external transmittance also includes light reflection losses at the sample surface.

[0473] The production of the optical glass, the production of the press-molding glass material, the production of the optical element blank, and the production of the optical element in the second embodiment can be the same as those in the first embodiment.

[0474] Third embodiment

[0475] In the optical glass of the third embodiment,

[0476] Si 4+ The content of cations is greater than 0% and less than 30%.

[0477] B 3+ The content of cations is greater than 0% and less than 50.00%.

[0478] Al 3+ The content of cationic ions is less than 13%,

[0479] Ca 2+ The content of cationic ions is less than 25%,

[0480] Zn 2+ The content of cationic ions is less than 6%,

[0481] Ge 4+ The content of cationic ions is less than 5%,

[0482] F - The content of anions is 10% or more,

[0483] La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 30 cation % or more,

[0484] Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is 0.070 or more,

[0485] La 3+ 、Gd 3+ 、Y 3+ 、Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3 + 、P 5+ 、Ti 4+ 、Nb 5+ 、W6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 above 0.84.

[0486] In the optical glass of the third embodiment, Si 4+ The content of Si is greater than 0% and less than 30%. 4+ The lower limit of the content of Si is preferably 0.60%, and more preferably 1.20%, 1.80%, 2.40%, 3.00%, 3.60%, 4.20%, 4.80%, 5.40%, 6.00%, 6.60%, 7.20%, 7.80%, 8.40%, 9.00%, 9.60%, 10.20%, 10.80%, 11.40%, and 12.00%. 4+ The upper limit of the content is preferably 29.4%, and further more preferably 28.7%, 28.1%, 27.4%, 26.8%, 26.1%, 25.5%, 24.8%, 24.2%, 23.5%, 22.9%, 22.2%, 21.6%, 20.9%, 20.3%, 19.6%, 19.0%, 18.3%, 17.7%, and 17.0%.

[0487] Si 4+ It is a network forming component of glass. 4+ When the content of Si is within the above range, an optical glass having abnormal partial dispersion, improved chemical durability, mechanical properties and thermal stability can be obtained. 4+ If the content of Si is too low, there is a risk that the chemical durability, mechanical properties and thermal stability of the glass will be reduced. 4+If the content of MgO is too high, the solubility of the glass may be reduced, and the refractive index nd may be reduced. In addition, the thermal stability of the glass may be reduced, and the glass transition temperature Tg may be increased.

[0488] In the optical glass of the third embodiment, B 3+ The content of B is greater than 0% and less than 50.00%. 3+ The lower limit of the content of is preferably 1.10%, and more preferably 2.20%, 3.30%, 4.40%, 5.50%, 6.60%, 7.70%, 8.80%, 9.90%, 11.00%, 12.10%, 13.20%, 14.30%, 15.40%, 16.50%, 17.60%, 18.70%, 19.80%, 20.90%, and 22.00%. 3+ The upper limit of the content is preferably 49.3%, and further more preferably 48.5%, 47.8%, 47.0%, 46.3%, 45.5%, 44.8%, 44.0%, 43.3%, 42.5%, 41.8%, 41.0%, 40.3%, 39.5%, 38.8%, 38.0%, 37.3%, 36.5%, 35.8%, and 35.0%.

[0489] B 3+ It is a network forming component of glass. 3+ The chemical durability can be improved by setting the content of B in the above range. 3+ If the content of B is too low, there is a risk of reducing the thermal stability and mechanical properties of the glass. 3+ When the content of is too high, there is a risk that the volatilization of glass components increases, and there is a risk that the thermal stability and chemical durability of the glass decrease.

[0490] In the optical glass of the third embodiment, Al 3+ The content of Al is less than 13%. 3+ The upper limit of the content of Al is preferably 12.4%, and more preferably 11.8%, 11.2%, 10.6%, 10.0%, 9.4%, 8.8%, 8.2%, 7.6%, 7.0%, 6.4%, 5.8%, 5.2%, 4.6%, 4.0%, 3.4%, 2.8%, 2.2%, 1.6%, and 1.0%. 3+The lower limit of the content of Al is preferably 0%, and more preferably 0.03%, 0.05%, 0.08%, 0.10%, 0.13%, 0.15%, 0.18%, 0.20%, 0.23%, 0.25%, 0.28%, 0.30%, 0.33%, 0.35%, 0.38%, 0.40%, 0.43%, 0.45%, 0.48%, and 0.50%. 3+ The content can be 0%.

[0491] For Al 3+ In terms of the glass phase separation, it can be suppressed by adding an appropriate amount of Al. 3+ The content of Al improves the mechanical properties and chemical durability of the glass. 3+ If the content of Al is too high, the liquidus temperature rises, which impairs the thermal stability of the glass. If the liquidus temperature rises, the volatilization of the glass components increases when the glass is flowing out and formed, which causes the generation of striae. 3+ When the content of is within the above range, the thermal stability of the glass can be maintained.

[0492] In the optical glass of the third embodiment, Ca 2+ The content of Ca is less than 25%. 2+ The upper limit of the content of Ca is preferably 23.8%, and more preferably 22.6%, 21.4%, 20.2%, 19.0%, 17.8%, 16.6%, 15.4%, 14.2%, 13.0%, 11.8%, 10.6%, 9.4%, 8.2%, 7.0%, 5.8%, 4.6%, 3.4%, 2.2%, and 1.0%. 2+ The lower limit of the content of Ca is preferably 0%, and more preferably 0.03%, 0.05%, 0.08%, 0.10%, 0.13%, 0.15%, 0.18%, 0.20%, 0.23%, 0.25%, 0.28%, 0.30%, 0.33%, 0.35%, 0.38%, 0.40%, 0.43%, 0.45%, 0.48%, and 0.50%. 2+ The content can be 0%.

[0493] By adding Ca 2+ When the content of Ca is within the above range, an optical glass having desired optical constants can be obtained. 2+ When the content of MgO is too high, the thermal stability of the glass is impaired, and there is a risk that the glass transition temperature Tg and the liquidus temperature TL may increase.

[0494] In the optical glass of the third embodiment, Zn 2+ The content of Zn is less than 6%.2+ The upper limit of the content of Zn is preferably 5.8%, and more preferably 5.5%, 5.3%, 5.0%, 4.8%, 4.5%, 4.3%, 4.0%, 3.8%, 3.5%, 3.3%, 3.0%, 2.8%, 2.5%, 2.3%, 2.0%, 1.8%, 1.5%, 1.3%, and 1.0%. 2+ The lower limit of the content of Zn is preferably 0%, and more preferably 0.03%, 0.05%, 0.08%, 0.10%, 0.13%, 0.15%, 0.18%, 0.20%, 0.23%, 0.25%, 0.28%, 0.30%, 0.33%, 0.35%, 0.38%, 0.40%, 0.43%, 0.45%, 0.48%, and 0.50%. 2+ The content can be 0%.

[0495] Zn 2+ It is a glass component that has the effect of lowering the glass transition temperature Tg by introduction. 2+ When the content of Zn is within the above range, an optical glass having an improved glass transition temperature Tg can be obtained. 2+ When the content of is too high, there is a risk that the specific gravity increases, and there is a risk that the thermal stability and chemical durability of the glass decrease. In addition, the Abbe number increases, and as a result, there is a risk that the desired high refractive index characteristics cannot be obtained.

[0496] In the optical glass of the third embodiment, Ge 4+ The content of Ge is less than 5%. 4+ The upper limit of the content of Ge is preferably 4.5%, and more preferably 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, and 0.5%. 4+ The lower limit of the content of Ge is preferably 0%. 4+ The content can be 0%.

[0497] Ge 4+ It has the function of improving the dispersion of glass and is an especially expensive component among the commonly used glass components. 4+ Setting the content of MgO within the above range can reduce the manufacturing cost of the glass.

[0498] The optical glass of the third embodiment includes F - As anionic component. - The content of anion is 10% or more. -The lower limit of the content of is preferably 11% anion, further preferably 12% anion, 13% anion, 14% anion, 15% anion, 16% anion, 17% anion, 18% anion, 19% anion, 20% anion, 21% anion, 22% anion, 23% anion, 24% anion, 25% anion, 26% anion, 27% anion, 28% anion, 29% anion, 30% anion, 31% anion, 32% anion, 33% anion, 34% anion. In addition, F - The upper limit of the content of is preferably 90 anion%, and more preferably 85 anion%, 80 anion%, 75 anion%, 70 anion%, 68 anion%, 66 anion%, 64 anion%, 62 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%. By adding F - By setting the content of F in the above range, an optical glass having high refractive index, high thermal stability, abnormal partial dispersion, low glass transition temperature Tg, and suitable for precision press molding can be obtained despite having low dispersion. - If the content of F is too low, there is a risk that the thermal stability of the glass will be reduced, and there is a risk that the abnormal partial dispersion property cannot be obtained. - When the content is too high, there is a risk of increased volatilization of glass components.

[0499] In the optical glass of the third embodiment, La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 30% or more. The lower limit of the total content is preferably 32%, and more preferably 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, and 60% in that order. In addition, the upper limit of the total content is preferably 80%, and more preferably 79%, 78%, 77%, 76%, 75%, 74%, 73%, 72%, 71%, 70%, 69%, 68%, 67%, 66%, 65%, 64%, 63%, and 62% in that order. By setting the total content to 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, there is a risk that the desired optical constants cannot be obtained. If the total content is too high, there is a risk that the thermal stability of the glass is reduced.

[0500] In the optical glass of the third embodiment, Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is 0.070 or more. The lower limit of the cation ratio is preferably 0.10, and more preferably 0.12, 0.14, 0.16, 0.18, 0.20, 0.22, 0.24, 0.26, 0.28, 0.30, 0.32, 0.34, 0.36, 0.38, and 0.40. In addition, the upper limit of the cation ratio is preferably 0.99, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.60, 0.55, 0.53, 0.51, 0.49, 0.47, 0.45, 0.43, and 0.42. By setting the cation ratio within the above range, an optical glass with improved chemical durability, mechanical properties, and thermal stability can be obtained.

[0501] In the optical glass of the third embodiment, La 3+ 、Gd 3+ 、Y 3+ 、Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、P 5+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(La 3+ +Gd 3+ +Y 3+ +Li + +Na + +K + +Rb + +Cs + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ) / (Si 4+ +B 3+ +P5+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+ The lower limit of the cation ratio is preferably 0.87, and more preferably 0.90, 0.93, 0.96, 0.99, 1.02, 1.05, 1.08, 1.11, 1.14, 1.17, 1.20, 1.23, 1.26, 1.29, 1.32, 1.35, 1.38, 1.41, 1.44, 1.47, 1.50, 1.53, or 1.56, respectively. The upper limit of the cation ratio is preferably 4.00, and more preferably 3.00, 2.95, 2.90, 2.85, 2.80, 2.75, 2.70, 2.65, 2.60, 2.55, 2.50, 2.45, 2.40, 2.35, 2.30, 2.25, 2.20, 2.15, 2.10, 2.05, 2.00, 1.95, 1.90, 1.85, 1.80, 1.75, 1.70, 1.65, and 1.60, respectively. By setting the cation ratio within the above range, the volatilization of the glass components can be suppressed. On the other hand, if the cation ratio is too low, there is a risk of increased volatilization of the glass components. In addition, if the cation ratio is too high, there is a risk of reduced thermal stability of the glass.

[0502] Hereinafter, non-limiting examples will be shown regarding the contents and ratios of glass components other than those described above in the optical glass of the third embodiment.

[0503] In the optical glass of the third embodiment, Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2 +The lower limit of ] is preferably 0%, and more preferably 0.50%, 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%, and 1.80%. The total content may be 0%. In addition, the upper limit of the total content is preferably 30%, and more preferably 25%, 20%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, and 3%. From the perspective of obtaining an optical glass having desired optical constants, reduced volatilization of glass components, and high thermal stability of the glass, it is preferred that the total content be within the above range. On the other hand, if the total content is too low, there is a risk of increased volatilization of glass components, reducing the thermal stability and devitrification resistance of the glass. On the other hand, if the total content is too high, there is a risk of impairing the high refractive index and the thermal stability of the glass.

[0504] In the optical glass of the third embodiment, 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+ The lower limit of the total content is preferably 0%, and more preferably 0.50%, 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%, and 1.80%. In addition, the upper limit of the total content is preferably 50%, and more preferably 45%, 40%, 35%, 30%, 25%, 20%, 18%, 16%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, and 2%. From the viewpoint of obtaining an optical glass having desired optical constants, a low glass transition temperature Tg, reduced volatilization of glass components, and high thermal stability, the total content is preferably within the above range.

[0505] In the optical glass of the third embodiment, Si 4+ and B 3+ The total content [Si 4+ +B 3+ The lower limit of the total content is preferably 10%, and more preferably 15%, 20%, 22%, 24%, 26%, 28%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, and 38%. In addition, the upper limit of the total content is preferably 70%, and more preferably 65%, 60%, 59%, 58%, 57%, 56%, 55%, 54%, 53%, 52%, 51%, 50%, 49%, 48%, 47%, 46%, 45%, 44%, 43%, 42%, 41%, 40%, and 39%. From the viewpoint of obtaining an optical glass having desired optical constants and anomalous partial dispersion, improved chemical durability, mechanical properties, and thermal stability, and suppressed volatilization of glass components during melting, the total content is preferably within the above range.

[0506] In the optical glass of the third embodiment, Li + 、Na + and K + The total content [Li + +Na + +K + The lower limit of the total content is preferably 0%, and more preferably 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, and 0.6%. Furthermore, the upper limit of the total content is preferably 50%, and more preferably 45%, 40%, 35%, 30%, 25%, 20%, 18%, 16%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, and 2%. The total content may be 0%. From the perspective of lowering the liquidus temperature of the glass and lowering the glass transition temperature Tg, the total content is preferably within the above range.

[0507] In the optical glass of the third embodiment, Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +Zn 2+The upper limit of the total content is preferably 30%, and more preferably 25%, 20%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, and 3%. The lower limit of the total content is preferably 0%, and more preferably 0.5%, 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%, and 1.80%. The total content may be 0%. If the total content is too high, there is a risk of impairing the high refractive index and the thermal stability of the glass. On the other hand, if the total content is too low, there is a risk of increased volatilization of glass components and reduced thermal stability and devitrification resistance of the glass. Therefore, the total content is preferably within the above range.

[0508] In the optical glass of the third embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content [Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The lower limit of the total content is preferably 0%, and more preferably 0.50%, 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%, and 1.80%. In addition, the upper limit of the total content is preferably 50%, and more preferably 45%, 40%, 35%, 30%, 25%, 20%, 18%, 16%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, and 2%. From the viewpoint of obtaining an optical glass having desired optical constants, having a low glass transition temperature Tg and a low liquidus temperature of the glass, and having reduced volatilization of glass components during melting, the total content is preferably within the above range.

[0509] In the optical glass of the third embodiment, Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content [Ti 4++Nb 5+ +W 6+ +Bi 3+ ] The lower limit of the total content is preferably 0%, and is more preferably 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, and 1.8%. In addition, the upper limit of the total content is preferably 20%, and is more preferably 18%, 16%, 14%, 12%, 10%, 9%, 8%, 7%, 6%, 5.0%, 4.5%, 4.0%, 3.5%, 3.0%, and 2.5%. From the viewpoint of maintaining high refractive index and low dispersion, the total content may be 0%. In addition, from the viewpoint of maintaining the desired Abbe number νd and improving the anomalous partial dispersion in the visible to near-ultraviolet region, it is preferred that the total content be within the above range.

[0510] In the optical glass of the third embodiment, Zr 4+ and Ta 5+ The total content [Zr 4+ +Ta 5+ The upper limit of the total content is preferably 20%, and more preferably 15%, 10%, 9%, 8%, 7%, 6%, 5%, and 4%. In addition, the lower limit of the total content is preferably 0%, and more preferably 0.5%, 1.0%, 1.5%, 2.0%, and 2.5%. From the perspective of maintaining high refractive index and low dispersion, the total content may be 0%. In addition, from the perspective of maintaining the thermal stability of the glass, it is preferable to set the total content within the above range. If the total content is too high, there is a risk of reduced thermal stability of the glass and increased raw material costs.

[0511] In the optical glass of the third embodiment, Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total content [Ti 4+ +Nb 5+ +Bi 3+ +W 6+ +Zr 4+ +Ta 5+The upper limit of the total content is preferably 20%, and more preferably 18%, 16%, 14%, 12%, 10%, 9%, 8%, 7%, and 6%. In addition, the lower limit of the total content is preferably 0%, and more preferably 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, and 4.5%. From the perspective of maintaining high refractive index and low dispersion, the total content may be 0%. In addition, from the perspective of maintaining the desired Abbe number νd and improving the anomalous partial dispersion in the visible to near-ultraviolet region, it is preferred that the total content be within the above range.

[0512] In the optical glass of the third embodiment, B 3+ The content relative to Si 4+ and B 3+ The total content of cation ratio [B 3 + / (Si 4+ +B 3+ The upper limit of the cation ratio is preferably 0.93, and more preferably 0.90, 0.88, 0.86, 0.84, 0.82, 0.80, 0.78, 0.76, 0.74, 0.72, 0.70, 0.68, 0.66, 0.64, 0.62, and 0.60. In addition, the lower limit of the cation ratio is preferably 0.10, and more preferably 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.47, 0.49, 0.51, 0.53, 0.55, 0.57, and 0.58. From the viewpoint of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above range.

[0513] In the optical glass of the third embodiment, Si 4+ 、B 3+ and P 5+ The total content [Si 4+ +B 3+ +P 5+The lower limit of the total content is preferably 10%, and more preferably 15%, 20%, 22%, 24%, 26%, 28%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, and 38%. In addition, the upper limit of the total content is preferably 70%, and more preferably 65%, 60%, 59%, 58%, 57%, 56%, 55%, 54%, 53%, 52%, 51%, 50%, 49%, 48%, 47%, 46%, 45%, 44%, 43%, 42%, 41%, 40%, and 39%. From the viewpoint of obtaining an optical glass having desired optical constants and anomalous partial dispersion, improved chemical durability, mechanical properties, and thermal stability, and suppressed volatilization of glass components during melting, the total content is preferably within the above range.

[0514] In the optical glass of the third embodiment, Si 4+ The content relative to Si 4+ 、B 3+ and P 5+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ +P 5+ The upper limit of the cation ratio is preferably 0.99, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.60, 0.55, 0.53, 0.51, 0.49, 0.47, 0.45, 0.43, and 0.42. In addition, the lower limit of the cation ratio is preferably 0.07, and more preferably 0.10, 0.12, 0.14, 0.16, 0.18, 0.20, 0.22, 0.24, 0.26, 0.28, 0.30, 0.32, 0.34, 0.36, 0.38, and 0.40. From the viewpoint of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above range.

[0515] In the optical glass of the third embodiment, B 3+ The content relative to Si 4+ 、B 3+ and P 5+ The total content of cation ratio [B 3+ / (Si 4+ +B 3+ +P 5+The upper limit of the cation ratio is preferably 0.93, and more preferably 0.90, 0.88, 0.86, 0.84, 0.82, 0.80, 0.78, 0.76, 0.74, 0.72, 0.70, 0.68, 0.66, 0.64, 0.62, and 0.60. In addition, 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, 0.47, 0.49, 0.51, 0.53, 0.55, 0.57, and 0.58. From the viewpoint of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above range.

[0516] In the optical glass of the third embodiment, P 5+ The content relative to Si 4+ 、B 3+ and P 5+ The total 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. Furthermore, the lower limit of the cation ratio is preferably 0, and more preferably 0.005, 0.01, and 0.015. The cation ratio may be 0. From the perspective of obtaining an optical glass with improved chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above range.

[0517] In the optical glass of the third embodiment, Li + The content relative to Li + 、Na + and K + The total cation content ratio [Li + / (Li + +Na + +K + The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, or 0.85. In addition, 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, or 0.7. The cation ratio may be 1. From the perspective of suppressing a decrease in stability during reheating and lowering the glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0518] In the optical glass of the third embodiment, Na + The content relative to Li + 、Na+ and K + The total cation 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, or 0.3 in that order. Furthermore, the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, or 0.15 in that order. The cation ratio may be 0. From the perspective of suppressing a decrease in stability during reheating and lowering the glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0519] In the optical glass of the third embodiment, K + The content relative to Li + 、Na + and K + The total content of cation ratio [K + / (Li + +Na + +K + The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, or 0.3 in that order. Furthermore, the lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, or 0.15 in that order. The cation ratio may be 0. From the perspective of suppressing a decrease in stability during reheating and lowering the glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0520] In the optical glass of the third embodiment, Mg 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total cation content ratio [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, 0.5, 0.45, and 0.4. 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, and 0.3. The cation ratio may be 0. From the viewpoint of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0521] In the optical glass of the third embodiment, Ca2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total cation content ratio [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, or 0.15. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 or 0.1. The cation ratio may be 0. From the perspective of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0522] In the optical glass of the third embodiment, Sr 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content of cation ratio [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, or 0.15. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 or 0.1. The cation ratio may be 0. From the perspective of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0523] In the optical glass of the third embodiment, Ba 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content of cation ratio [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, 0.50, 0.55, and 0.60. 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, and 0.70. From the viewpoint of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0524] In the optical glass of the third embodiment, Mg 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ The total cation content ratio [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, 0.5, 0.45, and 0.4. 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, and 0.3. The cation ratio may be 0. From the viewpoint of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0525] In the optical glass of the third embodiment, Ca 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ The total cation content ratio [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, or 0.15. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 or 0.1. The cation ratio may be 0. From the perspective of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0526] In the optical glass of the third embodiment, Sr 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ The total content of cation ratio [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, or 0.15. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 or 0.1. The cation ratio may be 0. From the perspective of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0527] In the optical glass of the third embodiment, Ba 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ The total content of cation ratio [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 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, and 0.60. 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, and 0.70. The cation ratio may be 0. From the viewpoint of suppressing a decrease in stability and thermal stability of the glass during reheating, the cation ratio is preferably within the above range.

[0528] In the optical glass of the third embodiment, Zn 2+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ and Zn 2+ The total content of cation ratio [Zn 2+ / (Mg 2+ +Ca 2+ +Sr2+ +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, or 0.15. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 or 0.1. The cation ratio may be 0. From the perspective of suppressing a decrease in stability and thermal stability of the glass during reheating and maintaining the high refractive index of the glass, the cation ratio is preferably within the above range.

[0529] In the optical glass of the third embodiment, La 3+ The content relative to La 3+ 、Gd 3+ and Y 3+ The total content of cation ratio [La 3+ / (La 3+ +Gd 3+ +Y 3+ 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, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.62, 0.64, 0.66, and 0.68. The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.78, 0.76, 0.74, and 0.72. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0530] In the optical glass of the third embodiment, Gd 3+ The content relative to La 3+ 、Gd 3+ and Y 3+ The total content of cation ratio [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, 0.48, 0.46, 0.44, 0.42, 0.40, 0.38, 0.36, 0.34, 0.32. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.05, 0.10, 0.15, 0.20, 0.22, 0.24, 0.26, 0.28. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd and suppressing the decrease in the thermal stability of the glass, reducing the amount of Gd as a heavy rare earth 3+From the viewpoint of the content of cations and the viewpoint of suppressing an increase in raw material costs, it is preferred that the cation ratio be within the above range.

[0531] In the optical glass of the third embodiment, Y 3+ The content relative to La 3+ 、Gd 3+ and Y 3+ The total 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, 0.93, 0.91, 0.89, 0.87, 0.85, 0.84, 0.83, 0.82, 0.81, 0.80, 0.79, 0.78, 0.77, 0.76, 0.75, 0.74, 0.73, 0.72, 0.71, and 0.70. 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, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, and 0.67. 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 to set the cation ratio to the above range.

[0532] In the optical glass of the third embodiment, Ti 4+ The content relative to Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content of cation ratio [Ti 4+ / (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, 0.4, 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. 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. The cation ratio may be 0. From the perspective of increasing the refractive index nd while maintaining the desired Abbe number νd and the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0533] In the optical glass of the third embodiment, Nb 5+ The content relative to Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content of cation ratio [Nb 5+ / (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, 0.74, 0.73, 0.72, 0.71, 0.70, 0.69, 0.68, and 0.67. 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. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd, maintaining the desired Abbe number νd, and maintaining the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0534] In the optical glass of the third embodiment, W 6+ The content relative to Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total 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. 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. The cation ratio may be 0. From the perspective of increasing the relative partial dispersion Pg,F, maintaining the desired Abbe number νd, and maintaining the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0535] In the optical glass of the third embodiment, Bi 3+The content relative to Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content of cation ratio [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, or 0.27. 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. The cation ratio is preferably within the above range from the viewpoints of increasing the refractive index nd and relative partial dispersion Pg,F, maintaining a desired Abbe number νd, maintaining the thermal stability of the glass, and reducing damage to platinum melting equipment.

[0536] In the optical glass of the third embodiment, Zr 4+ The content of Zr 4+ and Ta 5+ The total content of cation ratio [Zr 4+ / (Zr 4+ +Ta 5+ The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, or 0.85. The cation ratio may be 1. The lower limit of the cation ratio is preferably 0, and more preferably 0.5, 0.6, 0.7, or 0.8. From the perspective of maintaining the desired optical constants and suppressing raw material costs, the cation ratio is preferably within the above range.

[0537] In the optical glass of the third embodiment, Ta 5+ The content of Zr 4+ and Ta 5+ The total content of cation ratio [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, or 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 perspective of maintaining the desired optical constants and suppressing raw material costs, it is preferred that the cation ratio be within the above range.

[0538] In the optical glass of the third embodiment, Ti 4+ The content relative to Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total content of cation ratio [Ti 4+ / (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, 0.45, 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, 0.06. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd and maintaining the desired Abbe number νd, it is preferred that the cation ratio be within the above range.

[0539] In the optical glass of the third embodiment, Nb 5+ The content relative to Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total content of cation ratio [Nb 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 0.95, 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. 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. The cation ratio may be 0. From the viewpoint of increasing the refractive index nd and maintaining the desired Abbe number νd, it is preferred that the cation ratio be within the above range.

[0540] In the optical glass of the third embodiment, Bi 3+ The content relative to Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total content of cation ratio [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, or 0.11. 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. The cation ratio is preferably within the above range from the viewpoints of increasing the refractive index nd and relative partial dispersion Pg,F, maintaining a desired Abbe number νd, maintaining the thermal stability of the glass, and reducing damage to platinum melting equipment.

[0541] In the optical glass of the third embodiment, W 6+ The content relative to Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta5+ The total 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. 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. The cation ratio may be 0. From the perspective of increasing the relative partial dispersion Pg,F, maintaining the desired Abbe number νd, and maintaining the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0542] In the optical glass of the third embodiment, Zr 4+ The content relative to Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total content of cation ratio [Zr 4+ / (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 0.95, 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. 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. The cation ratio may be 0. From the perspective of increasing the refractive index nd while maintaining the desired Abbe number νd, and from the perspective of improving the mechanical properties and chemical durability of the glass, it is preferred that the cation ratio be within the above range.

[0543] In the optical glass of the third embodiment, Ta 5+The content relative to Ti 4+ 、Nb 5+ 、Bi 3+ 、W 6+ 、Zr 4+ and Ta 5+ The total content of cation ratio [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, or 0.04. 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 perspective of maintaining a desired constant and suppressing raw material costs, it is preferred that the cation ratio be within the above range.

[0544] In the optical glass of the third embodiment, Al 3+ The content relative to Si 4+ and B 3+ The total content of cations [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, 0.20, 0.18, 0.16, 0.14, 0.12, and 0.10. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.05, and 0.10. 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, which can impair the thermal stability of the glass. From the perspective of maintaining the thermal stability of the glass, the cation ratio is preferably within the above range.

[0545] In the optical glass of the third embodiment, Al 3+ The content relative to Li + 、Na + and K + The total content of cations [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, 0.2, 0.18, 0.16, 0.14, 0.12, and 0.10. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 and 0.10. The cation ratio can 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, which can impair the thermal stability of the glass. From the perspective of maintaining the thermal stability of the glass, it is preferable to set the cation ratio within the above range.

[0546] In the optical glass of the third embodiment, Al 3+ The content relative to Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content of cations [Al 3+ / (Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ The upper limit of the cation ratio is preferably 5, and more preferably 4, 3.5, 3.0, 2.5, 2, 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, 0.3, 0.2, 0.18, 0.16, 0.14, 0.12, and 0.10. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 and 0.10. 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, which impairs the thermal stability of the glass. From the perspective of maintaining the thermal stability and devitrification resistance of the glass, it is preferred that the cation ratio be within the above range.

[0547] In the optical glass of the third embodiment, Al 3+ The content relative to Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content of cations [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, 0.2, 0.18, 0.16, 0.14, 0.12, and 0.10. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 and 0.10. 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, which can impair the thermal stability of the glass. From the perspective of maintaining the thermal stability and devitrification resistance of the glass, it is preferred that the cation ratio be within the above range.

[0548] In the optical glass of the third embodiment, Al 3+ The content relative to La 3+ 、Gd 3+ and Y 3+ The total content of cations [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, 0.2, 0.18, 0.16, 0.14, 0.12, and 0.10. The lower limit of the cation ratio is preferably 0, and more preferably 0.05 and 0.10. The cation ratio may be 0. From the perspective of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0549] In the optical glass of the third embodiment, Li + 、Na + and K + The total content relative to Si 4+ and B 3+ The total cation content ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+The upper limit of the cation ratio is preferably 1, and more preferably 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.35, 0.3, 0.25, 0.20, 0.15, 0.1, 0.09, 0.08, 0.07, and 0.06. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04, and 0.05. The cation ratio may be 0. From the perspective of improving the chemical durability, mechanical properties, and thermal stability of the glass, suppressing the decrease in stability during reheating, and obtaining an optical glass with a lowered glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0550] In the optical glass of the third embodiment, Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(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 0.9, 0.8, 0.7, 0.6, 0.5, 0.45, 0.40, 0.35, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, 0.12, 0.10, 0.09, 0.08, 0.07, and 0.06. The lower limit of the cation ratio is preferably 0, and more preferably 0.005, 0.010, 0.015, 0.020, 0.025, 0.030, and 0.035. From the viewpoint of suppressing the reduction in chemical durability, mechanical properties, and thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0551] In the optical glass of the third embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr2+ +Ba 2+ ) / (Si 4+ +B 3+ The lower limit of the cation ratio is preferably 0, and more preferably 0.005, 0.010, 0.015, 0.020, 0.025, 0.030, or 0.035. The upper limit of the cation ratio is preferably 2, and more preferably 1.5, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.45, 0.40, 0.35, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, 0.12, 0.10, 0.09, 0.08, 0.07, or 0.06. From the perspective 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 preferred that the cation ratio be within the above range.

[0552] In the optical glass of the third embodiment, La 3+ 、Gd 3+ and Y 3+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+ )] is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, and 1.55, respectively. The upper limit of the cation ratio is preferably 3.00, and more preferably 2.95, 2.90, 2.85, 2.80, 2.75, 2.70, 2.65, 2.60, 2.55, 2.50, 2.45, 2.40, 2.35, 2.30, 2.25, 2.20, 2.15, 2.10, 2.05, 2.00, 1.95, 1.90, 1.85, 1.80, 1.75, 1.70, 1.65, and 1.60. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0553] In the optical glass of the third embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+、Sr 2+ 、Ba 2+ 、La 3+ 、Gd 3+ and Y 3+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(Li + +Na + +K + +Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ +La 3+ +Gd 3+ +Y 3 + ) / (Si 4+ +B 3+ )] is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, and 1.55, respectively. The upper limit of the cation ratio is preferably 4, and more preferably 3.00, 2.95, 2.90, 2.85, 2.80, 2.75, 2.70, 2.65, 2.60, 2.55, 2.50, 2.45, 2.40, 2.35, 2.30, 2.25, 2.20, 2.15, 2.10, 2.05, 2.00, 1.95, 1.90, 1.85, 1.80, 1.75, 1.70, 1.65, and 1.60. From the viewpoint of obtaining an optical glass that suppresses volatilization of glass components during melting and has excellent chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above range.

[0554] In the optical glass of the third embodiment, Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ) / (Si 4+ +B 3+The upper limit of the cation ratio is preferably 0, and more preferably 0.45, 0.40, 0.35, 0.30, 0.25, 0.20, 0.15, 0.14, 0.13, 0.12, 0.11, 0.10, 0.09, 0.08, 0.07, 0.06, and 0.05. The lower limit of the cation ratio is preferably 0, and more preferably 0.001, 0.002, 0.004, 0.006, 0.008, 0.010, 0.012, 0.014, 0.016, 0.018, 0.020, 0.022, 0.024, 0.026, 0.028, 0.030, 0.032, 0.034, 0.036, and 0.038. 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-mentioned range.

[0555] In the optical glass of the third embodiment, Zr 4+ and Ta 5+ The total content relative to Si 4+ and B 3+ The total cation content ratio [(Zr 4+ +Ta 5+ ) / (Si 4+ +B 3+ )] is preferably 0.5, and more preferably 0.45, 0.40, 0.35, 0.30, 0.25, 0.20, 0.15, 0.14, 0.13, 0.12, 0.11, 0.10, 0.09, 0.08, or 0.07, in that order. The lower limit of the cation ratio is preferably 0, and more preferably 0.002, 0.004, 0.006, 0.008, 0.010, 0.012, 0.014, 0.016, 0.018, 0.020, 0.022, 0.024, 0.026, 0.028, 0.030, 0.032, 0.034, 0.036, 0.038, 0.040, 0.042, 0.044, 0.046, 0.048, 0.050, 0.052, and 0.054, respectively. The cation ratio may be 0. From the viewpoint of maintaining the thermal stability of the glass and suppressing a decrease in the refractive index nd at the desired Abbe number vd, it is preferred that the cation ratio be within the above range.

[0556] In the optical glass of the third embodiment, Li + 、Na + and K + The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+and Bi 3+ The total cation content ratio [(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, 0.5, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.09, 0.08, 0.07, and 0.06. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04, and 0.05. The cation ratio may be 0. From the perspective of improving the chemical durability, mechanical properties, and thermal stability of the glass, suppressing the decrease in stability during reheating, and obtaining an optical glass with a lowered glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0557] In the optical glass of the third embodiment, Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total cation content ratio [(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 0.9, 0.8, 0.7, 0.6, 0.5, 0.45, 0.40, 0.35, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, 0.12, 0.10, 0.09, 0.08, 0.07, and 0.06. The lower limit of the cation ratio is preferably 0, and more preferably 0.005, 0.010, 0.015, 0.020, 0.025, 0.030, and 0.035. The cation ratio may be 0. From the viewpoint of suppressing the reduction in the chemical durability, mechanical properties, and thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0558] In the optical glass of the third embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total cation content ratio [(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, and more preferably 0.005, 0.010, 0.015, 0.020, 0.025, 0.030, or 0.035. The upper limit of the cation ratio is preferably 2, and more preferably 1.5, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.45, 0.40, 0.35, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, 0.12, 0.10, 0.09, 0.08, 0.07, or 0.06. The cation ratio may be 0. From the perspective 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 preferred that the cation ratio be within the above range.

[0559] In the optical glass of the third embodiment, La 3+ 、Gd 3+ and Y 3+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total cation content ratio [(La 3+ +Gd 3+ +Y 3+ ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ )] is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, and 1.55, respectively. The upper limit of the cation ratio is preferably 3.00, and more preferably 2.95, 2.90, 2.85, 2.80, 2.75, 2.70, 2.65, 2.60, 2.55, 2.50, 2.45, 2.40, 2.35, 2.30, 2.25, 2.20, 2.15, 2.10, 2.05, 2.00, 1.95, 1.90, 1.85, 1.80, 1.75, 1.70, 1.65, and 1.60. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0560] In the optical glass of the third embodiment, Li + 、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ 、La 3+ 、Gd 3+ and Y 3+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total cation content ratio [(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 preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, and 1.55, respectively. The upper limit of the cation ratio is preferably 4, and more preferably 3.00, 2.95, 2.90, 2.85, 2.80, 2.75, 2.70, 2.65, 2.60, 2.55, 2.50, 2.45, 2.40, 2.35, 2.30, 2.25, 2.20, 2.15, 2.10, 2.05, 2.00, 1.95, 1.90, 1.85, 1.80, 1.75, 1.70, 1.65, and 1.60. From the viewpoint of obtaining an optical glass that suppresses volatilization of glass components during melting and has excellent chemical durability, mechanical properties, and thermal stability, it is preferred that the cation ratio be within the above range.

[0561] In the optical glass of the third embodiment, Li + 、Na + and K + The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6 + 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(Li + +Na + +K + ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi3+ +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, 0.3, 0.25, 0.2, 0.15, 0.1, 0.09, 0.08, 0.07, and 0.06. The lower limit of the cation ratio is preferably 0, and more preferably 0.01, 0.02, 0.03, 0.04, and 0.05. The cation ratio may be 0. From the perspective of improving the chemical durability, mechanical properties, and thermal stability of the glass, suppressing the decrease in stability during reheating, and obtaining an optical glass with a lowered glass transition temperature Tg, it is preferred that the cation ratio be within the above range.

[0562] In the optical glass of the third embodiment, Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 0.9, 0.8, 0.7, 0.6, 0.5, 0.45, 0.40, 0.35, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, 0.12, 0.10, 0.09, 0.08, 0.07, and 0.06. The lower limit of the cation ratio is preferably 0, and more preferably 0.005, 0.010, 0.015, 0.020, 0.025, 0.030, and 0.035. From the viewpoint of suppressing the reduction in chemical durability, mechanical properties, and thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0563] In the optical glass of the third embodiment, Li +、Na + , K + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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, and more preferably 0.005, 0.010, 0.015, 0.020, 0.025, 0.030, or 0.035. The upper limit of the cation ratio is preferably 2, and more preferably 1.5, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.45, 0.40, 0.35, 0.30, 0.28, 0.26, 0.24, 0.22, 0.20, 0.18, 0.16, 0.14, 0.12, 0.10, 0.09, 0.08, 0.07, or 0.06. From the perspective 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 preferred that the cation ratio be within the above range.

[0564] In the optical glass of the third embodiment, La 3+ 、Gd 3+ and Y 3+ The total content relative to Si 4+ 、B 3+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(La 3+ +Gd3+ +Y 3+ ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+ )] is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, and 1.55, respectively. The upper limit of the cation ratio is preferably 3.00, and more preferably 2.95, 2.90, 2.85, 2.80, 2.75, 2.70, 2.65, 2.60, 2.55, 2.50, 2.45, 2.40, 2.35, 2.30, 2.25, 2.20, 2.15, 2.10, 2.05, 2.00, 1.95, 1.90, 1.85, 1.80, 1.75, 1.70, 1.65, and 1.60. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferred that the cation ratio be within the above range.

[0565] In the optical glass of the third embodiment, Li + The upper limit of the content of Li is preferably 31.0%, and more preferably 29.5%, 28.0%, 26.5%, 25.0%, 23.5%, 22.0%, 20.5%, 19.0%, 17.5%, 16.0%, 14.5%, 13.0%, 11.5%, 10.0%, 8.5%, 7.0%, 5.5%, 4.0%, 2.5%, and 1.0%. + The lower limit of the content of Li is preferably 0%, and more preferably 0.03%, 0.05%, 0.08%, 0.10%, 0.13%, 0.15%, 0.18%, 0.20%, 0.23%, 0.25%, 0.28%, 0.30%, 0.33%, 0.35%, 0.38%, 0.40%, 0.43%, 0.45%, 0.48%, and 0.50%. + The content of Li can be 0%. + It is a component that helps to lower the viscosity of glass. + If the content of Li is too high, there is a risk of reducing the thermal stability of the glass and the stability during reheating. + When the content of Li is too low, there is a risk of increasing the glass transition temperature Tg.+ The content of is preferably within the above range.

[0566] In the optical glass of the third embodiment, Na + The upper limit of the content of Na is preferably 31.0%, and more preferably 29.5%, 28.0%, 26.5%, 25.0%, 23.5%, 22.0%, 20.5%, 19.0%, 17.5%, 16.0%, 14.5%, 13.0%, 11.5%, 10.0%, 8.5%, 7.0%, 5.5%, 4.0%, 2.5%, and 1.0%. + The lower limit of the content of Na is preferably 0%, and more preferably 0.03%, 0.05%, 0.08%, 0.10%, 0.13%, 0.15%, 0.18%, 0.20%, 0.23%, 0.25%, 0.28%, 0.30%, 0.33%, 0.35%, 0.38%, 0.40%, 0.43%, 0.45%, 0.48%, and 0.50%. + The content of can be 0%. + Similarly, Na + It is a component that helps to lower the viscosity of glass. + If the content of Na is too high, there is a risk of reducing the thermal stability of the glass and the stability during reheating. + The content of is preferably within the above range.

[0567] In the optical glass of the third embodiment, K + The upper limit of the content of is preferably 31.0%, and more preferably 29.5%, 28.0%, 26.5%, 25.0%, 23.5%, 22.0%, 20.5%, 19.0%, 17.5%, 16.0%, 14.5%, 13.0%, 11.5%, 10.0%, 8.5%, 7.0%, 5.5%, 4.0%, 2.5%, and 1.0%. + The lower limit of the content of K is preferably 0%, and more preferably 0.03%, 0.05%, 0.08%, 0.10%, 0.13%, 0.15%, 0.18%, 0.20%, 0.23%, 0.25%, 0.28%, 0.30%, 0.33%, 0.35%, 0.38%, 0.40%, 0.43%, 0.45%, 0.48%, and 0.50%. + The content of K can be 0%. + It has the effect of lowering the liquidus temperature and improving the thermal stability of the glass. + When the content of K is too high, chemical durability, weather resistance, and stability during reheating are reduced. +The content of is preferably within the above range.

[0568] In the optical glass of the third embodiment, Mg 2+ The upper limit of the content of Mg is preferably 31.0%, and more preferably 29.5%, 28.0%, 26.5%, 25.0%, 23.5%, 22.0%, 20.5%, 19.0%, 17.5%, 16.0%, 14.5%, 13.0%, 11.5%, 10.0%, 8.5%, 7.0%, 5.5%, 4.0%, 2.5%, and 1.0%. 2+ The lower limit of the content of Mg is preferably 0%, and more preferably 0.03%, 0.05%, 0.08%, 0.10%, 0.13%, 0.15%, 0.18%, 0.20%, 0.23%, 0.25%, 0.28%, 0.30%, 0.33%, 0.35%, 0.38%, 0.40%, 0.43%, 0.45%, 0.48%, and 0.50%. 2+ The content of Mg can be 0%. 2+ If the content of Mg is too high, there is a risk that the thermal stability and devitrification resistance of the glass will be reduced. 2+ If the content of Mg is too low, there is a risk that the stability of the glass will be reduced during reheating. 2+ The content of is preferably within the above range.

[0569] In the optical glass of the third embodiment, Sr 2+ The upper limit of the content of Sr is preferably 31.0%, and more preferably 29.5%, 28.0%, 26.5%, 25.0%, 23.5%, 22.0%, 20.5%, 19.0%, 17.5%, 16.0%, 14.5%, 13.0%, 11.5%, 10.0%, 8.5%, 7.0%, 5.5%, 4.0%, 2.5%, and 1.0%. 2+ The lower limit of the content of Sr is preferably 0%, and more preferably 0.03%, 0.05%, 0.08%, 0.10%, 0.13%, 0.15%, 0.18%, 0.20%, 0.23%, 0.25%, 0.28%, 0.30%, 0.33%, 0.35%, 0.38%, 0.40%, 0.43%, 0.45%, 0.48%, and 0.50%. 2+ The content of Sr can be 0%. 2+ It is a component in alkaline earth metals that increases the refractive index nd. 2+ If the content of Sr is too high, there is a risk of reducing the thermal stability and devitrification resistance of the glass. 2+ The content of is preferably within the above range.

[0570] In the optical glass of the third embodiment, Ba 2+ The upper limit of the content of Ba is preferably 31.0%, and more preferably 29.5%, 28.0%, 26.5%, 25.0%, 23.5%, 22.0%, 20.5%, 19.0%, 17.5%, 16.0%, 14.5%, 13.0%, 11.5%, 10.0%, 8.5%, 7.0%, 5.5%, 4.0%, 2.5%, and 1.0%. 2+ The lower limit of the content of Ba is preferably 0%, and more preferably 0.03%, 0.05%, 0.08%, 0.10%, 0.13%, 0.15%, 0.18%, 0.20%, 0.23%, 0.25%, 0.28%, 0.30%, 0.33%, 0.35%, 0.38%, 0.40%, 0.43%, 0.45%, 0.48%, and 0.50%. 2+ The content of Ba can be 0%. 2+ Ba is a component that increases the refractive index nd among alkaline earth metals. It is also a component that lowers the liquidus temperature and improves the stability of glass by containing it in an appropriate amount. 2+ If the content of Ba is too high, there is a risk of reducing the thermal stability of the glass and the stability during reheating. 2+ If the content of Ba is too low, there is a risk of reducing the thermal stability of the glass and increasing the volatilization of the components of the glass during melting. 2+ The content of is preferably within the above range.

[0571] In the optical glass of the third embodiment, La 3+ The lower limit of the content of La is preferably 0%, and more preferably 0.90%, 1.80%, 2.70%, 3.60%, 4.50%, 5.40%, 6.30%, 7.20%, 8.10%, 9.00%, 9.90%, 10.80%, 11.70%, 12.60%, 13.50%, 14.40%, 15.30%, 16.20%, 17.10%, and 18.00%. 3+ The upper limit of the content of La is preferably 70.0%, and more preferably 68.2%, 66.3%, 64.5%, 62.6%, 60.8%, 58.9%, 57.1%, 55.2%, 53.4%, 51.5%, 49.7%, 47.8%, 46.0%, 44.1%, 42.3%, 40.4%, 38.6%, 36.7%, 34.9%, and 33.0%. 3+ , thereby inhibiting the volatilization of glass components and increasing the refractive index nd. However, La 3+When the content of La becomes too high, there is a risk that the thermal stability of the glass will decrease and the glass will easily become devitrified during production. 3+ The content of is preferably within the above range.

[0572] In the optical glass of the third embodiment, Gd 3+ The upper limit of the content of Gd is preferably 70.0%, and more preferably 67.2%, 64.4%, 61.6%, 58.8%, 56.0%, 53.2%, 50.4%, 47.6%, 44.8%, 42.0%, 39.2%, 36.4%, 33.6%, 30.8%, 28.0%, 25.2%, 22.4%, 19.6%, 16.8%, and 14.0%. 3+ The lower limit of the content of Gd is preferably 0%, and more preferably 0.60%, 1.20%, 1.80%, 2.40%, 3.00%, 3.60%, 4.20%, 4.80%, 5.40%, 6.00%, 6.60%, 7.20%, 7.80%, 8.40%, 9.00%, 9.60%, 10.20%, 10.80%, 11.40%, and 12.00%. 3+ The content of La can be 0%. 3+ Similarly, by introducing a certain amount of Gd 3+ , thereby inhibiting the volatilization of glass components and increasing the refractive index nd. On the other hand, Gd 3+ When the content of Gd becomes too much, the thermal stability of the glass decreases. 3+ If the content of Gd becomes too high, the specific gravity of the glass increases, which is not preferable. In addition, there is a hidden danger of increased raw material costs. Therefore, from the perspective of maintaining good thermal stability of the glass and suppressing the increase in specific gravity, and reducing the content of Gd as a heavy rare earth, the glass should be treated with a high-pressure glass. 3+ From the perspective of the content of Gd 3+ The content of is preferably within the above range.

[0573] In the optical glass of the third embodiment, Y 3+ The upper limit of the content of is preferably 70.0%, and more preferably 68.7%, 67.3%, 66.0%, 64.6%, 63.3%, 61.9%, 60.6%, 59.2%, 57.9%, 56.5%, 55.2%, 53.8%, 52.5%, 51.1%, 49.8%, 48.4%, 47.1%, 45.7%, 44.4%, and 43.0%. 3+The lower limit of the content is preferably 0%, and more preferably 2.05%, 4.10%, 6.15%, 8.20%, 10.25%, 12.30%, 14.35%, 16.40%, 18.45%, 20.50%, 22.55%, 24.60%, 26.65%, 28.70%, 30.75%, 32.80%, 34.85%, 36.90%, 38.95%, and 41.00%. 3+ The content can be 0%.

[0574] By importing a certain amount of Y 3+ , thereby inhibiting the volatilization of glass components and increasing the refractive index nd. However, Y 3+ When the content of Y becomes too high, the thermal stability of the glass decreases and the glass is easily devitrified during production. 3+ If the content of Y is too low, there is also a risk of reducing the thermal stability of the glass. Therefore, from the perspective of suppressing the reduction of the thermal stability of the glass, Y 3+ The content of is preferably within the above range.

[0575] In the optical glass of the third embodiment, Ti 4+ The upper limit of the content of Ti is preferably 10.0%, and more preferably 9.0%, 8.0%, 7.0%, 6.0%, 5.0%, 4.5%, 4.0%, 3.5%, 3.0%, 2.5%, 2.3%, 2.0%, 1.7%, 1.4%, 1.1%, 0.9%, 0.7%, 0.5%, 0.4%, and 0.3%. 4+ The lower limit of the content of Ti is preferably 0%, and may further be 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14% or 0.15%. 4+ The content of Ti may be 0%. From the viewpoint of maintaining the desired Abbe number νd and improving the anomalous partial dispersion in the visible to near ultraviolet region, it is preferred to 4+ The content of is set within the above range.

[0576] In the optical glass of the third embodiment, Nb 5+ The upper limit of the content of Nb is preferably 10.0%, and more preferably 9.0%, 8.0%, 7.0%, 6.0%, 5.0%, 4.5%, 4.0%, 3.7%, 3.5%, 3.3%, 3.1%, 2.9%, 2.7%, 2.5%, 2.3%, 2.1%, 1.9%, 1.7%, 1.6%, and 1.5%. 5+The lower limit of the content of Nb is preferably 0%, and more preferably 0.06%, 0.11%, 0.17%, 0.22%, 0.28%, 0.33%, 0.39%, 0.44%, 0.50%, 0.55%, 0.61%, 0.66%, 0.72%, 0.77%, 0.83%, 0.88%, 0.94%, 0.99%, 1.05%, and 1.10%. 5+ The content of Nb can be 0%. From the viewpoint of maintaining the desired Abbe number νd and improving the anomalous partial dispersion in the visible to near ultraviolet region, it is preferred to 5+ The content of is set within the above range.

[0577] In the optical glass of the third embodiment, W 6+ The upper limit of the content is preferably 10.0%, and more preferably 9.0%, 8.0%, 7.0%, 6.0%, 5.0%, 4.5%, 4.0%, 3.5%, 3.0%, 2.8%, 2.6%, 2.4%, 2.2%, 2.0%, 1.8%, 1.6%, 1.4%, 1.2%, 1.0%, and 0.8%. 6+ The lower limit of the content of W is preferably 0%, and more preferably 0.02%, 0.04%, 0.06%, 0.08%, 0.10%, 0.12%, 0.14%, 0.16%, 0.18%, 0.20%, 0.22%, 0.24%, 0.26%, 0.28%, 0.30%, 0.32%, 0.34%, 0.36%, 0.38%, and 0.40%. 6+ The content of W can be 0%. From the perspective of improving transmittance and reducing specific gravity, and maintaining the desired Abbe number νd and improving the anomalous partial dispersion in the visible to near ultraviolet region, it is preferred to 6+ The content of is set within the above range.

[0578] In the optical glass of the third embodiment, Zr 4+ The upper limit of the content of Zr is preferably 10.0%, and more preferably 9.0%, 8.0%, 7.0%, 6.0%, 5.5%, 5.0%, 4.5%, 4.3%, 4.1%, 4.0%, 3.9%, 3.8%, 3.7%, 3.6%, 3.5%, 3.4%, 3.3%, 3.2%, 3.1%, and 3.0%. 4+The lower limit of the content of Zr is preferably 0%, and more preferably 0.13%, 0.25%, 0.38%, 0.50%, 0.63%, 0.75%, 0.88%, 1.00%, 1.13%, 1.25%, 1.38%, 1.50%, 1.63%, 1.75%, 1.88%, 2.00%, 2.13%, 2.25%, 2.38%, and 2.50%. 4+ The content of Zr can be 0%. 4+ It has the effect of improving chemical durability. However, Zr 4+ If the content of Zr is too high, there is a risk of the liquidus temperature LT rising and the solubility of the glass decreasing. 4+ The content of is set within the above range.

[0579] In the optical glass of the third embodiment, Sb ions may be added from the viewpoint of suppressing a decrease in transmittance near a wavelength of 360 nm and near a wavelength of 375 nm. The upper limit of the Sb ion content is preferably 1.0000 mass%, 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 addition, the lower limit of the Sb ion content is preferably 0.0001 mass% in terms of the added ratio, and further more preferably 0.0005 mass%, 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%.

[0580] Sb ions can be added to the glass by, for example, Sb2O3 or Sb2S3. Sb ions include all Sb ions with trivalence, pentavalence, and other valence numbers. In addition, the content of Sb ions is an added ratio. That is, the content of Sb ions is expressed in mass % when the total content of all glass components other than Sb ions is set to 100 mass %. From the viewpoint of suppressing the reduction of the transmittance near a wavelength of 360nm and a wavelength of 375nm, it is preferred that the content of Sb ions be set to the above range. If the content of Sb ions is too much, Pt from the crucible is easily introduced into the glass, forming a Pt colloid and generating a Tyndall-like blur in the glass, which has the hidden danger of deteriorating the light transmittance that is not dependent on the wavelength range. Moreover, there is a hidden danger of deteriorating the light transmittance of a specific wavelength due to the light absorption of the Sb ions themselves. When no Sb ions are contained or the Sb ion content is too low, absorption by Pt ions near a wavelength of 360 nm becomes significant, resulting in a risk of deteriorating light transmittance at specific wavelengths extending into the visible light wavelength range.

[0581] The optical glass of the third embodiment includes O 2- As anionic component. 2- The upper limit of the content of is preferably 90 anion%, further more preferably 89 anion%, 88 anion%, 87 anion%, 86 anion%, 85 anion%, 84 anion%, 83 anion%, 82 anion%, 81 anion%, 80 anion%, 79 anion%, 78 anion%, 77 anion%, 76 anion%, 75 anion%, 74 anion%, 73 anion%. In addition, O 2- The lower limit of the content is preferably 10 anion%, and further 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%, 36 anion%, 38 anion%, 40 anion%, 42 anion%, 44 anion%, 46 anion%, 48 anion%, 50 anion%, and 52 anion%.

[0582] In the optical glass of the third embodiment, the contents and ratios of the glass components other than those described above can be the same as those of the first embodiment.

[0583] (Glass properties)

[0584] <Abbe number νd>

[0585] In the optical glass of the third embodiment, the upper limit of the Abbe number νd is preferably 70, and may be 68, 66, 64, 62, 60, 58, 56, 54, 52, or 50. The lower limit of the Abbe number νd is preferably 37.5, and may be 39, 40, 41, 42, 43, 44, 45, 46, 47, or 48.

[0586] The Abbe number νd is calculated in the same manner as in the first embodiment. The Abbe number νd can be set to a desired value by appropriately adjusting the content of each glass component. The component that relatively reduces the Abbe number, 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+ wait.

[0587] <Refractive Index nd>

[0588] In the optical glass of the third embodiment, the upper limit of the refractive index nd is preferably 1.92, and may be 1.87, 1.82, 1.80, 1.79, or 1.78. The lower limit of the refractive index nd is preferably 1.60, and may be 1.65, 1.70, 1.75, 1.76, or 1.77.

[0589] The refractive index nd can be set to a desired value by appropriately adjusting the content of each glass component. The component that has the effect of relatively increasing the refractive index nd (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 has the effect of relatively lowering the refractive index nd (refractive index lowering component) is Si 4+ 、B 3+ 、Li + 、Na + , K + wait.

[0590] In the optical glass of the third embodiment, the refractive index nd and the Abbe number νd preferably satisfy the following formula [1-1].

[0591] nd≥(-0.0081×νd+2.1181)···[1-1]

[0592] The refractive index nd and the Abbe number νd more preferably satisfy the following formula [1-2], and further more preferably satisfy the following formula [1-3], the following formula [1-4], and the following formula [1-5] in that order.

[0593] nd≥(-0.0081×νd+2.1231)···[1-2]

[0594] nd≥(-0.0081×νd+2.1281)···[1-3]

[0595] nd≥(-0.0081×νd+2.1331)···[1-4]

[0596] nd≥(-0.0081×νd+2.1381)···[1-5]

[0597] <Relative partial dispersion Pg,F>

[0598] In the optical glass of the third embodiment, the lower limit of the relative partial dispersion Pg,F in the short wavelength region of visible light is preferably 0.5200, and more preferably 0.5250, 0.5300, 0.5350, 0.5400, 0.5450, 0.5460, 0.5470, 0.5480, 0.5490, 0.5500, 0.5510, 0.5520, 0.5530, 0.5540, 0.5550, 0.5560, and 0.5570, respectively. By setting the relative partial dispersion Pg,F within the above range, an optical glass suitable for compensating for high-order chromatic aberrations can be obtained. Meanwhile, the upper limit of the relative partial dispersion Pg,F is not particularly limited, but is typically 0.5700, preferably 0.5650.

[0599] In the optical glass of the third embodiment, the relative partial dispersion Pg,F preferably satisfies the following formula [2-1].

[0600] Pg,F≥0.6200-0.0014×νd···[2-1]

[0601] The relative partial dispersion Pg,F more preferably satisfies the following formula [2-2], and further 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 this order.

[0602] Pg,F≥0.6220-0.0014×νd···[2-2]

[0603] Pg,F≥0.6240-0.0014×νd···[2-3]

[0604] Pg,F≥0.6260-0.0014×νd···[2-4]

[0605] Pg,F≥0.6270-0.0014×νd···[2-5]

[0606] Pg,F≥0.6280-0.0014×νd···[2-6]

[0607] In the optical element made of the optical glass of the third embodiment, from the viewpoint of satisfactorily compensating for chromatic aberration in a wide wavelength range, it is preferable that the relative partial dispersion Pg,F satisfies the above-mentioned formula.

[0608] In the optical glass of the third 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, 0.0150, 0.0140, 0.0130, 0.0120, 0.0110, and 0.0100. On the other hand, the lower limit of ΔPg,F is preferably -0.0100, and further preferably -0.0090, -0.0080, -0.0070, -0.0060, -0.0050, -0.0040, -0.0030, -0.0020, -0.0010, and 0.0000. By setting ΔPg,F within the above range, an optical glass suitable for compensating for high-order chromatic aberration can be obtained.

[0609] The relative partial dispersion Pg,F and ΔPg,F are calculated in the same manner as in the first embodiment.

[0610] <Specific Gravity of Glass>

[0611] The specific gravity of the optical glass of the third embodiment is preferably 6.0 or less, and more preferably 5.9 or less, 5.8 or less, 5.7 or less, 5.6 or less, 5.5 or less, and 5.4 or less in this order.

[0612] The component that relatively increases the specific gravity is Ba 2+ 、La 3+ 、Zr 4+ 、Nb 5+ 、Ta 5+ On the other hand, the relatively low specific gravity component is Si 4+ 、B 3+ 、Li + 、Na + Mg2+ The specific gravity can be controlled by appropriately adjusting the contents of these components.

[0613] <Liquid phase temperature LT>

[0614] The upper limit of the liquidus temperature LT of the optical glass of the third embodiment is preferably 1200°C, and more preferably 1150°C, 1140°C, 1130°C, 1120°C, 1110°C, 1100°C, 1090°C, 1080°C, 1070°C, 1060°C, 1050°C, 1040°C, 1030°C, 1020°C, 1010°C, 1000°C, 990°C, 980°C, 970°C, 960°C, 950°C, 940°C, 930°C, 920°C, 910°C, and 900°C. By setting the liquidus temperature within the above range, the melting and forming temperatures of the glass can be lowered. As a result, the generation of striae caused by erosion of glass melting tools (e.g., crucibles, stirring tools for molten glass, etc.) during the melting process and volatilization of the glass components themselves can be reduced. The lower limit of the liquidus temperature LT is not particularly limited. The liquidus temperature LT is determined by the balance of the contents of all glass components. 4+ 、B 3+ 、Li + 、Na + , K + The content of Zr is also greatly affected. 4+ 、Al 3+ When the content is high, the liquidus temperature rises. The liquidus temperature is determined in the same manner as in the first embodiment.

[0615] <Glass transition temperature Tg>

[0616] The upper limit of the glass transition temperature Tg of the optical glass of the third embodiment is preferably 625°C, and more preferably 623°C, 621°C, 619°C, 617°C, 615°C, 613°C, 611°C, 609°C, and 607°C. Furthermore, the lower limit of the glass transition temperature Tg is preferably 350°C, and more preferably 370°C, 390°C, 410°C, 430°C, 450°C, 470°C, 490°C, 510°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, and 590°C. From the perspective of improving the yield during precision press molding, it is preferable to set the glass transition temperature Tg within the above range. On the other hand, if the glass transition temperature Tg is too high, there is a risk that precision press molding may not be possible.

[0617] The component that relatively lowers the glass transition temperature Tg is Li + 、Na + , K + 、F- The component that relatively increases the glass transition temperature Tg is La 3+ 、Zr 4+ 、Nb 5+ The glass transition temperature Tg can be controlled by appropriately adjusting the contents of these components.

[0618] <Light Transmittance of Glass>

[0619] The light transmittance of the optical glass of the third embodiment can be evaluated by the coloration degrees λ80, λ70, and λ5.

[0620] For a glass sample with a thickness of 10.0 mm ± 0.1 mm, the spectral transmittance is measured within the wavelength range of 200 to 700 nm, and the wavelength at which the external transmittance reaches 80% is set as λ80, the wavelength at which the external transmittance reaches 70% is set as λ70, and the wavelength at which the external transmittance reaches 5% is set as λ5.

[0621] The optical glass of the third embodiment preferably has a λ80 of 450 nm or less, more preferably 400 nm or less, and even more preferably 370 nm or less. The λ70 is preferably 430 nm or less, more preferably 380 nm or less, and even more preferably 360 nm or less. The λ5 is preferably 380 nm or less, more preferably 330 nm or less, and even more preferably 320 nm or less.

[0622] <Chemical durability acid resistance Da>

[0623] In the optical glass of the third embodiment, the acid resistance Da is preferably level 5 or higher, and more preferably level 4 or higher, level 3 or higher, level 2 or higher, and level 1 or higher. The acid resistance Da is evaluated in the same manner as in the first embodiment.

[0624] <Chemical durability and water resistance Dw>

[0625] In the optical glass of the third embodiment, the water resistance Dw is preferably level 5 or higher, and more preferably level 4 or higher, level 3 or higher, level 2 or higher, and level 1 or higher in this order. The water resistance Dw is evaluated in the same manner as in the first embodiment.

[0626] <Mechanical properties Knoop hardness Hk>

[0627] The lower limit of the Knoop hardness Hk of the optical glass of the third embodiment is preferably 400, and more preferably 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, and 550, respectively. The Knoop hardness Hk is preferably within the above range from the perspective of preventing damage during glass handling and during mechanical processing such as grinding and cutting to manufacture lenses. The upper limit of the Knoop hardness Hk is not particularly limited, but is generally 750, preferably 600.

[0628] Knoop hardness Hk can be adjusted by La 3+ 、Gd 3+ 、Y 3+ 、Si 4+ 、Zr 4+ 、Al 3+ content is increased.

[0629] <ΔT360>

[0630] In the optical glass of the third embodiment, when the thickness is 10.0 mm ± 0.1 mm, the upper limit of the difference between the external transmittance at a wavelength of 700 nm and the external transmittance at a wavelength of 360 nm (ΔT360) 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%. The lower limit of ΔT360 is not particularly limited, but is generally 2 to 30%. ΔT360 can be adjusted by introducing Sb ions. Furthermore, from the perspective of maintaining low dispersion, the use of high-dispersion components such as Ti, Nb, W, and Bi is not preferred. Incorporating these components for purposes such as achieving higher refractive index or higher anomalous dispersion increases ΔT360. By setting ΔT360 within the above range, the decrease in transmittance around a wavelength of 360 nm can be suppressed.

[0631] <ΔT375>

[0632] In the optical glass of the third embodiment, when the thickness is set to 10.0 mm ± 0.1 mm, the upper limit of the difference between the external transmittance at a wavelength of 700 nm and the external transmittance at a wavelength of 375 nm (ΔT375) is preferably 15.0%, and more preferably 13.0%, 11.0%, 10.0%, 9.0%, 8.0%, 7.5%, 7.0%, 6.8%, 6.7%, 6.6%, 6.5%, 6.4%, 6.3%, 6.2%, 6.1%, and 6.0%. The lower limit of ΔT375 is not particularly limited, but is generally 2 to 15%. ΔT375 can be adjusted by introducing Sb ions. In addition, from the perspective of maintaining low dispersion, the use of high-dispersion components such as Ti, Nb, W, and Bi is not preferred. When these are introduced for the purpose of high refractive index or high anomalous dispersion, ΔT375 increases. By setting ΔT375 within the above range, a decrease in transmittance near a wavelength of 375 nm can be suppressed.

[0633] External transmittance is defined as the percentage of transmitted light intensity relative to incident light intensity when light is incident along the thickness of a glass sample [transmitted light intensity / incident light intensity × 100]. It should be noted that external transmittance also includes light reflection losses at the sample surface.

[0634] The production of the optical glass, the production of the press-molding glass material, the production of the optical element blank, and the production of the optical element in the third embodiment can be the same as those in the first embodiment.

[0635] Fourth embodiment

[0636] In the optical glass of the fourth embodiment,

[0637] B 3+ The content of cations is greater than 0% and less than 50.00%.

[0638] La 3+ The content of cations is greater than 0% and less than 70%.

[0639] Zn 2+ The content of cationic ions is less than 6.5%,

[0640] F - The content of anions is 10% or more,

[0641] La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 30 cation % or more,

[0642] Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content [Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ] less than 2.0 cation%,

[0643] Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is below 0.77,

[0644] La 3+ 、Gd 3+ 、Y 3+ 、Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3 + 、P 5+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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+ +Ta5+ )] is 0.84 or more,

[0645] The content of Sb ions is 1.0 mass ppm or more in terms of added ratio,

[0646] When the thickness is set to 10.0 mm±0.1 mm, 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.

[0647] In the optical glass of the fourth embodiment, B 3+ The content of B is greater than 0% and less than 50.00%. 3+ The lower limit of the content of is preferably 1.00%, and more preferably 2.00%, 3.00%, 4.00%, 5.00%, 6.00%, 7.00%, 8.00%, 9.00%, 10.00%, 11.00%, 12.00%, 13.00%, 14.00%, 15.00%, 16.00%, 17.00%, 18.00%, 19.00%, and 20.00%. 3+ The upper limit of the content is preferably 45.00%, and further more preferably 44.00%, 43.00%, 42.00%, 41.00%, 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%, and 24.00%.

[0648] B 3+ It is a network forming component of glass. 3+ The chemical durability can be improved by setting the content of B in the above range. 3+ If the content of B is too low, there is a risk of reducing the thermal stability and mechanical properties of the glass. 3+ When the content of is too high, there is a risk that the volatilization of glass components increases, and there is a risk that the thermal stability and chemical durability of the glass decrease.

[0649] In the optical glass of the fourth embodiment, La 3+ The content of La is greater than 0% and less than 70%. 3+The lower limit of the content of La is preferably 0.90%, and more preferably 1.80%, 2.70%, 3.60%, 4.50%, 5.40%, 6.30%, 7.20%, 8.10%, 9.00%, 9.90%, 10.80%, 11.70%, 12.60%, 13.50%, 14.40%, 15.30%, 16.20%, 17.10%, and 18.00%. 3+ The upper limit of the content of La is preferably 65%, and more preferably 60%, 55%, 50%, 48%, 46%, 44%, 42%, 40%, 38%, 36%, 34%, 32%, 30%, 28%, 26%, and 24%. 3+ Setting the content of La in the above range can suppress the volatilization of glass components and increase the refractive index nd. 3+ When the content of MgO becomes too high, there is a risk that the thermal stability of the glass decreases and the glass is easily devitrified during production.

[0650] In the optical glass of the fourth embodiment, Zn 2+ The content of Zn is less than 6.5%. 2+ The upper limit of the content of Zn is preferably 6.0%, and more preferably 5.5%, 5.0%, 4.5%, 4.0%, 3.5%, 3.0%, 2.5%, 2.0%, and 1.5%. 2+ The lower limit of the content of Zn is preferably 0%, and more preferably 0.03%, 0.05%, 0.08%, 0.10%, 0.13%, 0.15%, 0.18%, 0.20%, 0.23%, 0.25%, 0.28%, 0.30%, 0.33%, 0.35%, 0.38%, 0.40%, 0.43%, 0.45%, 0.48%, and 0.50%. 2+ The content can be 0%.

[0651] Zn 2+ It is a glass component that has the effect of lowering the glass transition temperature Tg by introduction. 2+ When the content of Zn is within the above range, an optical glass having an improved glass transition temperature Tg can be obtained. 2+ When the content of is too high, there is a risk that the specific gravity increases, and there is a risk that the thermal stability and chemical durability of the glass decrease. In addition, the Abbe number increases, and as a result, there is a risk that the desired high refractive index characteristics cannot be obtained.

[0652] The optical glass of the fourth embodiment includes F - As anionic component. - The content of anion is 10% or more. -The lower limit of the content of is preferably 12% anion, and further preferably 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, 41% anion, 42% anion, 43% anion, 44% anion, 45% anion, 46% anion. In addition, F - The upper limit of the content of is preferably 90 anion%, and further more preferably 85 anion%, 80 anion%, 75 anion%, 70 anion%, 68 anion%, 66 anion%, 64 anion%, 62 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%. By adding F - By setting the content of F in the above range, an optical glass having high refractive index, high thermal stability, abnormal partial dispersion, low glass transition temperature Tg, and suitable for precision press molding can be obtained despite having low dispersion. - If the content of F is too low, there is a risk that the thermal stability of the glass will be reduced, and there is a risk that the abnormal partial dispersion property cannot be obtained. - When the content is too high, there is a risk of increased volatilization of glass components.

[0653] In the optical glass of the fourth embodiment, La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 30% or more. The lower limit of the total content is preferably 32%, and more preferably 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, and 60% in that order. In addition, the upper limit of the total content is preferably 80%, and more preferably 79%, 78%, 77%, 76%, 75%, 74%, 73%, 72%, 71%, 70%, 69%, 68%, 67%, 66%, 65%, 64%, 63%, and 62% in that order. By setting the total content to the above range, an optical glass with a higher refractive index nd can be obtained. On the other hand, if the total content is too low, there is a risk that the desired optical constants cannot be obtained. If the total content is too high, there is a risk that the thermal stability of the glass is reduced.

[0654] In the optical glass of the fourth embodiment, Ti4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content [Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ] is less than 2.0%. The upper limit of the total content is preferably 1.9%, and more preferably 1.8%, 1.7%, 1.6%, 1.5%, 1.4%, 1.3%, 1.2%, 1.1%, 1.0%, 0.9%, 0.8%, and 0.7%. The lower limit of the total content is preferably 0.00%, and more preferably 0.05%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, 0.40%, 0.45%, and 0.50%. The total content may be 0%. From the perspective of maintaining high refractive index and low dispersion, the total content may be 0%. In addition, from the perspective of maintaining the desired Abbe number νd and improving the anomalous partial dispersion in the visible to near-ultraviolet region, it is preferable that the total content be within the above range.

[0655] In the optical glass of the fourth embodiment, Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is 0.77 or less. The upper limit of the cation ratio is preferably 0.75, and more preferably 0.73, 0.71, 0.69, 0.67, 0.65, 0.63, 0.61, 0.59, 0.57, 0.55, 0.53, 0.51, 0.49, 0.47, 0.45, 0.43, and 0.42. In addition, the lower limit of the cation ratio is preferably 0.00, and more preferably 0.02, 0.04, 0.06, 0.08, 0.10, 0.12, 0.14, 0.16, 0.18, 0.20, 0.22, 0.24, 0.26, 0.28, 0.30, 0.32, 0.34, 0.36, 0.38, and 0.40. By setting the cation ratio within the above range, an optical glass having improved chemical durability, mechanical properties, and thermal stability can be obtained.

[0656] In the optical glass of the ...

Claims

1. An optical glass, wherein: Si 4+ The content of cations is greater than 0% and less than 30%. B 3+ The content of cations is greater than 0% and less than 50.00%. F - The content of anions is 10% or more, Ca 2+ The content of cationic ions is less than 25%, Zn 2+ The content of cationic ions is less than 13%, Ge 4+ The content of cationic ions is less than 5%, La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 30 cation % or more, Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ] is 3.5 cation % or more, 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 3.5 cation % or more, Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is 0.020 or more, La 3+ 、Gd 3+ 、Y 3+ 、Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、P 5+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 above 0.

83.

2. An optical glass, wherein: Si 4+ The content of cations is greater than 0% and less than 30%. B 3+ The content of cations is greater than 0% and less than 50.00%. F - The content of anions is 10% or more, Ca 2+ The content of cationic ions is less than 25%, Zn 2+ The content of cationic ions is less than 13%, Ge 4+ The content of cationic ions is less than 5%, La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 27 cation % or more, Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ Total content [Mg 2+ +Ca 2+ +Sr 2+ +Ba 2+ ] is 3.5 cation % or more, 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 3.5 cation % or more, Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is 0.070 or more, La 3+ 、Gd 3+ 、Y 3+ 、Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、P 5+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 0.83 or more, Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content [Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ] is greater than 0 cation %.

3. An optical glass, wherein: Si 4+ The content of cations is greater than 0% and less than 30%. B 3+ The content of cations is greater than 0% and less than 50.00%. Al 3+ The content of cationic ions is less than 13%, Ca 2+ The content of cationic ions is less than 25%, Zn 2+ The content of cationic ions is less than 6%, Ge 4+ The content of cationic ions is less than 5%, F - The content of anions is 10% or more, La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 30 cation % or more, Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is 0.070 or more, La 3+ 、Gd 3+ 、Y 3+ 、Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、P 5+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 above 0.

84.

4. An optical glass, wherein: B 3+ The content of cations is greater than 0% and less than 50.00%. La 3+ The content of cations is greater than 0% and less than 70%. Zn 2+ The content of cationic ions is less than 6.5%, F - The content of anions is 10% or more, La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 30 cation % or more, Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content [Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ] less than 2.0 cation%, Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is below 0.77, La 3+ 、Gd 3+ 、Y 3+ 、Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、P 5+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 0.84 or more, The content of Sb ions is 1.0 mass ppm or more in terms of added ratio, When the thickness is set to 10.0 mm±0.1 mm, 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.

5. An optical glass, wherein: B 3+ The content of cations is greater than 0% and less than 50.00%. La 3+ The content of cations is greater than 0% and less than 70%. Zn 2+ The content of cationic ions is less than 6.5%, F - The content of anions is 10% or more, La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 30 cation % or more, Ti 4+ 、Nb 5+ 、W 6+ and Bi 3+ The total content [Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ] is 2.0 cation % or more, Si 4+ The content relative to Si 4+ and B 3+ The total content of cations is [Si 4+ / (Si 4+ +B 3+ )] is below 0.77, La 3+ 、Gd 3+ 、Y 3+ 、Li + 、Na + , K + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ And Ba 2+ The total content relative to Si 4+ 、B 3+ 、P 5+ 、Ti 4+ 、Nb 5+ 、W 6+ 、Bi 3+ 、Zr 4+ and Ta 5+ The total cation content ratio [(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 0.84 or more, The content of Sb ions is 1.0 mass ppm or more in terms of added ratio, When the thickness is set to 10.0 mm±0.1 mm, the difference between the external transmittance at a wavelength of 700 nm and the external transmittance at a wavelength of 375 nm is 7.5% or less. 6 . A press-molding glass material, comprising the optical glass according to claim 1 .

7. An optical element made of the optical glass according to any one of claims 1 to 5.

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