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 mechanical characteristics, and are not high in glass transition temperature. The optical glass has an Abbe number vd of 62.00 or more, a B3 + content of more than 0 cation% but 50.00 cation% or less, a Si4 + content of more than 0 cation%, a F-content of more than 0 anion%, and a total content [La < 3 + > + Gd < 3 + > + Y < 3 + >] of La < 3 + >, Gd < 3 + > and Y < 3 + > of 5 cation% or more.

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 single-lens reflex cameras, as well as mobile information terminals such as smart phones. In these applications, in order to improve the yield rate during lens manufacturing, it is desirable that the mechanical properties of the glass be high. In addition, for example, when processing glass into aspheric lenses, processing of glass with a high glass transition temperature sometimes becomes difficult. Therefore, a glass with a lower glass transition temperature is required.

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

[0004] Therefore, the present invention focuses on B-La-F-based glass. Conventionally, most components contributing to low dispersion in B-La-F-based glass volatilize during melting, making it difficult to increase the Abbe number νd. The present invention suppresses the volatilization of glass components by adjusting the glass composition, resulting in a glass with an Abbe number νd of 62 or greater and excellent mechanical properties.

[0005] Patent Document 1 discloses a fluorine-containing optical glass having a large Abbe number relative to its refractive index and excellent devitrification resistance. Patent Document 2 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 discloses an optical glass with an Abbe number νd of 62 or greater.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 56-169150

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2017-19670 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 in mechanical properties, and 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] The Abbe number νd is 62.00 or more,

[0016] B 3+ The content of cations is greater than 0% and less than 50.00%.

[0017] Si 4+ The content of cations is greater than 0%,

[0018] F - The content of anions is greater than 0%,

[0019] La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 5 cation % or more.

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

[0021] 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 0.50.

[0022] (3) An optical glass, wherein:

[0023] The Abbe number νd is 62.00 or more,

[0024] B 3+ The content of cations is greater than 0% and less than 50.00%.

[0025] F - The content of anion is greater than 0% and less than 85%.

[0026] La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 5 cation % or more,

[0027] 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+ 、Nb5+ 、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 0.60 or more,

[0028] Si 4+ and B 3+ The total content relative to Si 4+ 、B 3+ and P 5+ The total content of cation ratio [(Si 4+ +B 3+ ) / (Si 4 + +B 3+ +P 5+ )] is above 0.2.

[0029] (4) The optical glass according to (1) to (3), wherein

[0030] The content of Sb ions is 1.0 mass ppm or more in terms of added proportion.

[0031] (5) The optical glass according to (1) to (3), wherein:

[0032] 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.

[0033] (6) A glass material for press molding, which is made of the optical glass described in any one of (1) to (3) above.

[0034] (7) An optical element made of the optical glass described in any one of (1) to (3) above.

[0035] Effects of the Invention

[0036] According to the present invention, it is possible to provide an optical glass and an optical element which have desired optical constants, suppress degradation of mechanical properties, and have a low glass transition temperature. DETAILED DESCRIPTION

[0037] 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).

[0038] In addition, anion % means the molar percentage when the total content of all anion components is set to 100%.

[0039] The valence of the cationic component (e.g. B 3+ The valence is +3, Si 4+ 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] Unless otherwise specified, the refractive index refers to the refractive index nd under helium d-ray (wavelength 587.56 nm).

[0044] Hereinafter, the optical glass of the present invention will be described as a first embodiment and a second embodiment.

[0045] First embodiment

[0046] In the optical glass of the first embodiment,

[0047] The Abbe number νd is 62.00 or more,

[0048] B 3+ The content of cations is greater than 0% and less than 50.00%.

[0049] Si 4+ The content of cations is greater than 0%,

[0050] F - The content of anions is greater than 0%,

[0051] La 3+ 、Gd3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 5 cation % or more.

[0052] <Abbe number νd>

[0053] In the optical glass of the first embodiment, the Abbe number νd is 62.00 or greater, preferably 62 to 75, and may be 62.2 to 73, 62.4 to 71, 62.6 to 69, 62.8 to 68, 63 to 67, or 62 to 63.

[0054] 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 νd, 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.

[0055] In the present invention, the Abbe number νd and the relative partial dispersion Pg,F (described later) 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 - Measurement of Refractive Index - Part 1: Minimum Deviation Angle Method. The refractive index of each ray obtained from the measurements is then substituted into the Schott dispersion equation specified in Appendix B of the Japanese Industrial Standard (JIS) JIS B 7071-1, Optical Glass - Measurement 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 are calculated from the obtained refractive index values ​​for each ray.

[0056]

[0057] Schott dispersion type: n 2 =a0+a1λ 2 +a2λ-2 +a3λ -4 +a4λ -6 +a5λ -8

[0058] Where n is the refractive index, λ is the wavelength (μm), and a0, a1, a2, a3, a4, and a5 are constants.

[0059] 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.

[0060] νd=(nd-1) / (nF-nC)

[0061] 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%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, and 21%. 3+ The upper limit of the content is preferably 45.00%, and more preferably 40.00%, 39.00%, 38.00%, 37.00%, 36.00%, 35.00%, 34.00%, 33.00%, 32.00%, 31.00%, 30.00%, 29.00%, 28.00%, 27.00%, 26.00%, 25.00%, 24.00%, and 23.00%.

[0062] B 3+ It is a network forming component of glass. 3+ The chemical durability can be improved by setting the content of B to 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+ If the content of is too high, there is a risk of increased volatilization of glass components and a risk of reduced thermal stability and chemical durability of the glass.

[0063] In the optical glass of the first embodiment, Si 4+ The content is greater than 0%. Si 4+ The lower limit of the content of Si is preferably 1%, and more preferably 2%, 3%, 4%, 5%, 6%, 7%, and 8%. 4+ The upper limit of the content is preferably 30%, and more preferably 25%, 23%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, and 10%.

[0064] Si 4+ It is a network forming component of glass. 4+ When the content of Si is set to the above range, an optical glass having abnormal partial dispersion and improved chemical durability, mechanical properties and thermal stability can be obtained. 4+ If the content of Si is too low, there is a risk of reducing the chemical durability, mechanical properties and thermal stability of the glass. 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.

[0065] The optical glass of the first embodiment includes F - As anionic component, that is, F - The content of anion is greater than 0%. - The lower limit of the content of is preferably 5 anions, and further preferably 10 anions, 15 anions, 20 anions, 24 anions, 27 anions, 30 anions, 33 anions, 35 anions, 37 anions, 39 anions, 41 anions, 43 anions, 45 anions, 46 anions, 47 anions, 48 ​​anions, 49 anions, 50 anions, 51 anions, 52 anions, 53 anions, 54 anions, 55 anions, 56 anions, and 57 anions. In addition, F - The upper limit of the content of is preferably 80 anions, and further more preferably 77 anions, 75 anions, 73 anions, 71 anions, 69 anions, 67 anions, 65 anions, 64 anions, 63 anions, 62 anions, 61 anions, 60 anions, 59 anions. - When the content of F is set within 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. - If the content is too high, there is a hidden danger of increased volatilization of glass components.

[0066] 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 5% or more. The lower limit of this total content is preferably 10%, and further preferably 15%, 20%, 25%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38% in sequence. In addition, the upper limit of this total content is preferably 60%, and further more preferably 55%, 50%, 48%, 46%, 45%, 44%, 43%, 42%, 41% in sequence. By setting this total content to the above range, an optical glass with a high refractive index nd can be obtained. On the other hand, if this total content is too little, there is a hidden danger that the desired optical constants cannot be obtained. If this total content is too much, there is a hidden danger that the thermal stability of the glass decreases.

[0067] Hereinafter, non-limiting examples will be given of the contents of glass components other than those described above and glass properties in the optical glass of the first embodiment.

[0068] In the optical glass of the first embodiment, Si 4+ and B 3+ The total content [Si 4+ +B 3+ The lower limit of ] is preferably 10%, further more preferably 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 29%, 30% in sequence. In addition, the upper limit of this total content is preferably 70%, further more preferably 65%, 60%, 58%, 56%, 54%, 52%, 50%, 48%, 47%, 46%, 45%, 44%, 43%, 42%, 41%, 40%, 39%, 38%, 37%, 36%, 35%, 34%, 33%, 32% in sequence. From the viewpoint of obtaining the optical glass having the optical constant and abnormal part dispersion with expectation, improving chemical durability, mechanical properties and thermal stability, suppressing the volatilization of the glass component when melting, preferably this total content is set to above-mentioned scope.

[0069] In the optical glass of this embodiment, Li + 、Na + and K + The total content [Li + +Na + +K + The lower limit of the total content is preferably 0%, and further preferably 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, and 11% in sequence. In addition, the upper limit of the total content is preferably 50%, and further more preferably 45%, 40%, 35%, 30%, 25%, 20%, 18%, 16%, 14%, and 13% in sequence. From the viewpoint of lowering the liquidus temperature of the glass and lowering the glass transition temperature Tg, it is preferred that the total content be set to the above range.

[0070] 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+ ] The lower limit of the total content is preferably 0%, and further preferably 1%, 3%, 5%, 7%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%. In addition, the upper limit of the total content is preferably 30%, and further preferably 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, 19%. If the total content is too little, the volatilization of the glass component increases, and there is a hidden danger of reduced thermal stability and devitrification resistance of the glass. In addition, if the total content is too much, there is a hidden danger of impaired high refractive index and a hidden danger of impaired thermal stability of the glass. From the viewpoint of obtaining an optical glass with desired optical constants, reduced volatilization of glass components and high thermal stability of the glass, it is preferably set to the above range.

[0071] 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%, 29%, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, and 19% in this order. The lower limit of the total content is preferably 0%, and more preferably 1%, 3%, 5%, 7%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, and 16% in this order. If the total content is too much, there is a risk of impaired high refractive index and a risk of impaired thermal stability of the glass. In addition, if the total content is too little, the volatilization of the glass components increases, and there is a risk of reduced thermal stability and devitrification resistance of the glass. Therefore, the total content is preferably within the above range.

[0072] 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 ] is preferably 0%, further more preferably 1%, 3%, 5%, 7%, 9%, 11%, 13%, 15%, 17%, 19%, 21%, 23%, 25%, 27% in sequence. In addition, the upper limit of this total content is preferably 50%, further more preferably 45%, 42%, 40%, 39%, 38%, 37%, 36%, 35%, 34%, 33%, 32%, 31% in sequence. From the viewpoint of obtaining an optical glass with desired optical constants, lowering the liquidus temperature of glass transition temperature Tg and glass and reducing the volatilization of the glass component when melting, it is preferably set to above-mentioned range.

[0073] 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+ The lower limit of ] is preferably 0%, and further more preferably 1%, 3%, 5%, 7%, 9%, 11%, 13%, 15%, 17%, 19%, 21%, 23%, 25%, 27% in sequence. In addition, the upper limit of this total content is preferably 50%, and further more preferably 45%, 42%, 40%, 39%, 38%, 37%, 36%, 35%, 34%, 33%, 32%, 31% in sequence. From the viewpoint of obtaining an optical glass with desired optical constants, glass transition temperature Tg decline, volatilization of glass component reduction and high thermal stability, it is preferably set to above-mentioned range by this total content.

[0074] 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 further 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 further 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 vd and improving the dispersion of the abnormal part in the visible light to near ultraviolet region, it is preferred that the total content be set to the above range.

[0075] 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% in that order. In addition, the lower limit of the total content is preferably 0%, and more preferably 0.1%, 0.2%, and 0.3% in that order. From the 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 preferred that the total content be 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.

[0076] In the optical glass of the first 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 further preferably 15%, 10%, 5%, 4%, 3.5%, 3%, and 2.5%. In addition, the lower limit of the total content is preferably 0%, and further more preferably 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, and 1.6%. 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 dispersion of the abnormal part in the visible light to near ultraviolet region, it is preferred that the total content be set to the above range.

[0077] 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+ 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. Furthermore, 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. 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.

[0078] 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.

[0079] In the optical glass of the first embodiment, Si 4+ 、B 3+ and P 5+ The total content [Si 4+ +B 3+ +P5+ The lower limit of ] is preferably 10%, further more preferably 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 29%, 30% in sequence. In addition, the upper limit of this total content is preferably 70%, further more preferably 65%, 60%, 58%, 56%, 54%, 52%, 50%, 48%, 47%, 46%, 45%, 44%, 43%, 42%, 41%, 40%, 39%, 38%, 37%, 36%, 35%, 34%, 33%, 32% in sequence. From the viewpoint of obtaining the optical glass having the optical constant and abnormal part dispersion with expectation, improving chemical durability, mechanical properties and thermal stability, suppressing the volatilization of the glass component when melting, preferably this total content is set to above-mentioned scope.

[0080] 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.

[0081] 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.

[0082] 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, or 0.02. Furthermore, the lower limit of the cation ratio is preferably 0, and more preferably 0.005, 0.01, or 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.

[0083] In the optical glass of the first embodiment, Si 4+ and B 3+ The total content relative to Si 4+ 、B 3+ and P 5+ The total content of cation ratio [(Si 4+ +B 3+ ) / (Si 4+ +B 3+ +P 5+ The lower limit of the cation ratio is preferably 0.2, and more preferably 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.85, 0.9, or 0.95. Furthermore, the upper limit of the cation ratio is preferably 1, and more preferably 0.99, 0.98, or 0.97. The cation ratio may also be 1. From the perspective of obtaining an optical glass having excellent chemical durability and mechanical properties, it is preferred that the cation ratio be within the above range.

[0084] 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 also 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.

[0085] In the optical glass of the first embodiment, Na + The content relative to Li + 、Na + and K + The total cation content ratio [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.

[0086] 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.

[0087] 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, and 0.5 in this order. The lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.18, 0.2, 0.22, 0.24, 0.26, 0.28, 0.30, 0.32, 0.34, 0.36, 0.38, 0.40, 0.42, 0.44, and 0.46 in this order. The cation ratio may be 0. From the viewpoint of suppressing a decrease in stability and thermal stability of the glass during reheating, it is preferred that the cation ratio be within the above range.

[0088] 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.

[0089] 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.

[0090] 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, and 0.50. The upper limit of the cation ratio is preferably 1, and more preferably 0.90, 0.80, 0.75, 0.74, 0.73, 0.72, 0.71, 0.70, 0.69, 0.68, 0.67, 0.66, 0.65, 0.64, 0.63, 0.62, 0.61, 0.60, 0.59, 0.58, 0.57, 0.56, and 0.55. 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.

[0091] 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, and 0.5. The lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.18, 0.2, 0.22, 0.24, 0.26, 0.28, 0.30, 0.32, 0.34, 0.36, 0.38, 0.40, 0.42, 0.44, and 0.46. 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.

[0092] In the optical glass of the first embodiment, Ca 2+ The content relative to Mg 2+ , Ca 2+ 、Sr2+ 、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.

[0093] 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.

[0094] 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 0.1, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, and 0.50. The upper limit of the cation ratio is preferably 1, and more preferably 0.90, 0.80, 0.75, 0.74, 0.73, 0.72, 0.71, 0.70, 0.69, 0.68, 0.67, 0.66, 0.65, 0.64, 0.63, 0.62, 0.61, 0.60, 0.59, 0.58, 0.57, 0.56, and 0.55. 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.

[0095] 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 during reheating of the glass and maintaining the high refractive index of the glass, the cation ratio is preferably within the above range.

[0096] 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.

[0097] 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.

[0098] 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 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.

[0099] 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 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.

[0100] 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 perspective 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.

[0101] 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 improving the relative partial dispersion Pg,F, maintaining the desired Abbe number νd, and maintaining the thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0102] 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 improving the refractive index nd and relative partial dispersion Pg,F, maintaining a desired Abbe number νd and thermal stability of the glass, and reducing damage to platinum melting equipment.

[0103] 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 may be 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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 improving the refractive index nd and relative partial dispersion Pg,F, maintaining a desired Abbe number νd and thermal stability of the glass, and reducing damage to platinum melting equipment.

[0108] 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.

[0109] 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 and maintaining the desired Abbe number νd, as well as 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.

[0110] 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.

[0111] 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 becomes too high, the liquidus temperature rises, and the thermal stability of the glass is impaired. From the perspective of maintaining the thermal stability of the glass, the cation ratio is preferably within the above range.

[0112] 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 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 becomes too high, the liquidus temperature rises, and the thermal stability of the glass is impaired. From the perspective of maintaining the thermal stability of the glass, the cation ratio is preferably within the above range.

[0113] In the optical glass of the first embodiment, Al3+ 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 becomes too high, the liquidus temperature rises, and the thermal stability of the glass is impaired. From the perspective of maintaining the thermal stability and devitrification resistance of the glass, it is preferable to set the cation ratio within the above range.

[0114] 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 becomes too high, the liquidus temperature rises, and the thermal stability of the glass is impaired. 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.

[0115] In the optical glass of the first 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, 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.

[0116] 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, 0.75, 0.70, 0.65, 0.60, 0.55, 0.50, 0.45, 0.43, 0.42, 0.41, and 0.40. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.32, 0.33, 0.34, and 0.35. 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.

[0117] 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 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.68, 0.66, 0.64, 0.62, 0.60, 0.59, and 0.58. The lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.17, 0.19, 0.21, 0.23, 0.25, 0.27, 0.29, 0.31, 0.33, 0.35, 0.37, 0.39, 0.41, 0.43, 0.45, 0.47, 0.49, 0.51, 0.53, and 0.55. 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.

[0118] 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, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, and 0.95. The upper limit of the cation ratio is preferably 2, and more preferably 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, and 1.0. 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.

[0119] 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, 0.60, 0.70, 0.80, 0.90, 1.00, 1.02, 1.04, 1.06, 1.08, 1.10, 1.12, 1.14, 1.16, 1.18, 1.20, 1.21, 1.22, 1.23, 1.24, and 1.25. The upper limit of the cation ratio is preferably 3, and more preferably 2.5, 2, 1.9, 1.8, 1.75, 1.70, 1.65, 1.60, 1.55, 1.50, 1.45, 1.40, 1.38, 1.36, 1.34, 1.32, and 1.30. 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.

[0120] 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+)] is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, 1.90, 1.95, 2.00, 2.05, 2.10, 2.15, and 2.20. The upper limit of the cation ratio is preferably 4, and more preferably 3.5, 3.0, 2.8, 2.6, 2.5, 2.4, 2.37, 2.35, 2.33, 2.31, 2.29, 2.27, and 2.25, respectively. The cation ratio is preferably within the above range from the viewpoint of suppressing volatilization of glass components during melting and obtaining an optical glass that is excellent in chemical durability, mechanical properties, and thermal stability.

[0121] 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 νd, it is preferred that the cation ratio be within the above range.

[0122] 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 content of cation 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 preferable to set the cation ratio within the above range.

[0123] 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, 0.56, 0.54, 0.52, 0.50, 0.48, 0.46, 0.44, 0.42, and 0.40. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.07, 0.09, 0.11, 0.13, 0.15, 0.17, 0.19, 0.21, 0.23, 0.25, 0.27, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, and 0.37. 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.

[0124] 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 [(Mg2+ +Ca 2+ +Sr 2+ +Ba 2+ ) / (Si 4+ +B 3+ +Ti 4+ +Nb 5+ +W 6+ +Bi 3+ The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.63, 0.61, 0.60, and 0.59. The lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.17, 0.19, 0.21, 0.23, 0.25, 0.27, 0.29, 0.31, 0.33, 0.35, 0.37, 0.39, 0.41, 0.43, 0.45, 0.47, 0.49, 0.51, 0.53, and 0.55. 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.

[0125] 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, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.91, 0.92, 0.93, and 0.94. The upper limit of the cation ratio is preferably 3, and more preferably 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, and 1.05. 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 range.

[0126] 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+ )] is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.07, 1.09, 1.11, 1.13, 1.15, 1.17, 1.19, 1.20, 1.21, 1.22, 1.23, 1.24, and 1.25. The upper limit of the cation ratio is preferably 3, and more preferably 2.5, 2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.45, 1.40, 1.35, 1.34, 1.33, 1.32, 1.31, 1.30, 1.29, and 1.28, respectively. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0127] 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+ )] is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, 1.90, 1.95, 2.00, 2.05, 2.10, 2.15, and 2.20. The upper limit of the cation ratio is preferably 4, and more preferably 3.8, 3.6, 3.4, 3.2, 3.0, 2.9, 2.8, 2.7, 2.65, 2.60, 2.55, 2.50, 2.40, 2.35, 2.30, and 2.25, respectively. The cation ratio is preferably within the above range from the viewpoint of suppressing volatilization of glass components during melting and obtaining an optical glass having excellent chemical durability, mechanical properties, and thermal stability.

[0128] In the optical glass of the first embodiment, Li + 、Na + and K + The total content relative to Si 4+ 、B3+ 、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, 0.56, 0.54, 0.52, 0.50, 0.48, 0.46, 0.44, 0.42, and 0.40. The lower limit of the cation ratio is preferably 0, and more preferably 0.05, 0.07, 0.09, 0.11, 0.13, 0.15, 0.17, 0.19, 0.21, 0.23, 0.25, 0.27, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, and 0.37. 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.

[0129] 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+ +Zr4+ +Ta 5+ The upper limit of the cation ratio is preferably 1, and more preferably 0.95, 0.90, 0.85, 0.80, 0.75, 0.70, 0.65, 0.63, 0.61, 0.60, and 0.59. The lower limit of the cation ratio is preferably 0, and more preferably 0.1, 0.15, 0.17, 0.19, 0.21, 0.23, 0.25, 0.27, 0.29, 0.31, 0.33, 0.35, 0.37, 0.39, 0.41, 0.43, 0.45, 0.47, 0.49, 0.51, 0.53, and 0.55. 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.

[0130] 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+ 、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, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.91, 0.92, 0.93, and 0.94. The upper limit of the cation ratio is preferably 3, and more preferably 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, and 1.05. 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.

[0131] 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+ ) / (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, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.07, 1.09, 1.11, 1.13, 1.15, 1.17, 1.19, 1.20, 1.21, 1.22, 1.23, 1.24, and 1.25. The upper limit of the cation ratio is preferably 3, and more preferably 2.5, 2, 1.9, 1.8, 1.7, 1.6, 1.5, 1.45, 1.40, 1.35, 1.34, 1.33, 1.32, 1.31, 1.30, 1.29, and 1.28, respectively. From the viewpoint of increasing the refractive index nd and suppressing a decrease in the thermal stability of the glass, it is preferable that the cation ratio be within the above range.

[0132] 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+)] is preferably 0.01, and more preferably 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80, 0.90, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, 1.90, 1.95, 2.00, 2.05, 2.10, 2.15, and 2.20. The upper limit of the cation ratio is preferably 4, and more preferably 3.8, 3.6, 3.4, 3.2, 3.0, 2.9, 2.8, 2.7, 2.65, 2.60, 2.55, 2.50, 2.40, 2.35, 2.30, and 2.25, respectively. The cation ratio is preferably within the above range from the viewpoint of suppressing volatilization of glass components during melting and obtaining an optical glass having excellent chemical durability, mechanical properties, and thermal stability.

[0133] 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+ +Nb5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+ The lower limit of the cation ratio is preferably 0.50, and more preferably 0.60, 0.70, 0.80, 0.90, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, 1.90, 1.95, 2.00, 2.05, 2.10, 2.15, and 2.20. The upper limit of the cation ratio is preferably 4, and more preferably 3.8, 3.6, 3.4, 3.2, 3.0, 2.9, 2.8, 2.7, 2.65, 2.60, 2.55, 2.50, 2.40, 2.35, 2.30, and 2.25. If the cation ratio is too low, there is a risk of increased volatilization of glass components. On the other hand, if the cation ratio is too high, there is a risk of reduced thermal stability of the glass. From the perspective of suppressing the volatilization of glass components, it is preferable to set the cation ratio within the above range.

[0134] 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 is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5%. 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.

[0135] 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% in that order. 3+ The content of Al can be 0%. 3+ By adding an appropriate amount of Al, it has the function of suppressing the phase separation of glass. 3+ The content of Al can improve the mechanical properties and chemical durability of the glass. 3+If the content of Al increases, the liquidus temperature rises and the thermal stability of the glass is impaired. If the liquidus temperature rises, the volatilization of glass components increases when the glass is poured out and formed, which may cause wave streaks. From the perspective of maintaining the thermal stability of the glass, it is preferred to increase the content of Al. 3+ The content of is set within the above range.

[0136] In the 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%, and 12.5%. + The lower limit of the content is preferably 0%, and more preferably 1%, 2%, 3%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, and 11.5%. + The content of Li can be 0%. + It is a component that helps to reduce 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. + If 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.

[0137] In the 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 reduce 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.

[0138] 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 can be 0%. K + It has the function of lowering the liquidus temperature and improving the thermal stability of the glass. On the other hand, if K + If the content of K is too high, the chemical durability, weather resistance and stability during reheating will be reduced. + The content of is preferably within the above range.

[0139] 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%. + If the content of Rb increases, the volatilization of glass components during melting increases, and the desired glass cannot be obtained. In addition, since Rb is an expensive component, + The content of is preferably within the above range.

[0140] 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 of is preferably 0%. + The content of Cs can be 0%. + If the content of Cs increases, the volatilization of glass components during melting increases, and the desired glass cannot be obtained. In addition, there is a risk of reduced chemical durability and weather resistance. + The content of is preferably within the above range.

[0141] 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%, 18%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, and 9%. 2+ The lower limit of the content of Mg is preferably 0%, and more preferably 1%, 2%, 3%, 4%, 5%, 6%, 7%, and 8%. 2+ The content of Mg can be 0%. 2+ If the content of Mg is too high, there is a risk of reducing the thermal stability and devitrification resistance of the glass. 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.

[0142] In the optical glass of the first embodiment, Ca 2+ The upper limit of the content of Ca is preferably 25%, and more preferably 20%, 15%, 10%, 9%, 8%, 7%, 6%, and 5%. 2+ The lower limit of the content of Ca is preferably 0%, and more preferably 0.5%, 1%, and 2%. 2+ The content of Ca can be 0%. 2+ If the content of Ca is too high, the thermal stability of the glass will be impaired, and there is a risk of increasing the glass transition temperature Tg and the liquidus temperature TL. From the perspective of obtaining an optical glass with desired optical constants, it is preferred to reduce the content of Ca to 1. 2+ The content of is set within the above range.

[0143] 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 that increases the refractive index nd in alkaline earth metals. However, if Sr 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.

[0144] 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%, 11%, and 10%. 2+ The lower limit of the content of Ba is preferably 0%, and more preferably 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, and 9%. 2+ Ba is a component that increases the refractive index nd in alkaline earth metals. It is also a component that lowers the liquidus temperature and improves the stability of the glass by containing it in an appropriate amount. 2+ If the content of Ba is too high, the thermal stability of the glass and the stability during reheating may be reduced. 2+ If the content of Ba is too low, there is a risk of reduced thermal stability of the glass and increased volatilization of glass components during melting. 2+The content of is preferably within the above range.

[0145] In the optical glass of the first embodiment, Zn 2+ The upper limit of the content of Zn is preferably 13%, and more preferably 10%, 8%, 6%, and 5% in that order. 2+ The lower limit of the content of Zn is preferably 0%, and more preferably 0.5%, 1%, and 2% in that order. 2+ The content can be 0%.

[0146] Zn 2+ It is a glass component that has the function of lowering the glass transition temperature Tg. 2+ If the content of Zn is too high, there is a risk of increased specific gravity, decreased thermal stability and chemical durability of the glass, and an increase in the Abbe number, resulting in a risk of not being able to obtain the desired high refractive index characteristics. Therefore, from the perspective of obtaining an optical glass with an improved glass transition temperature Tg, it is preferred to add Zn 2+ The content of is set within the above range.

[0147] 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, if La 3+ If the content of La is too high, the thermal stability of the glass will decrease, and there is a risk that the glass will easily lose clarity during production. 3+ The content of is preferably within the above range.

[0148] In the 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+, can inhibit the volatilization of glass components and increase the refractive index nd. On the other hand, if Gd 3+ If the content of Gd becomes too much, the thermal stability of the glass will decrease. 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, and reducing the content of Gd as a heavy rare earth, the glass should be treated with a high-pressure glass. 3+ Considering the content of Gd 3+ The content of is preferably within the above range.

[0149] In the 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 is preferably 0%, and more preferably 1%, 5%, 8%, 10%, 12%, 14%, 16%, and 18%. 3+ The content can be 0%.

[0150] By importing a certain amount of Y 3+ , which can inhibit the volatilization of glass components and increase the refractive index nd. However, if Y 3+ If the content of Y is too high, the thermal stability of the glass will decrease and the glass will be easily devitrified during manufacturing. 3+ If the content of Y is too low, there is a hidden danger of reducing the thermal stability of the glass. Therefore, from the perspective of suppressing the reduction of the thermal stability of the glass, it is preferred that Y 3+ The content is within the above range.

[0151] In the 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+ Compared with Yb 3+ The molecular weight of Yb is large, so it will increase the specific gravity of the glass. 3+ If the content of Yb is too high, the thermal stability of the glass will decrease. 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.

[0152] 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 may be 0%. From the viewpoint of maintaining the desired Abbe number νd and improving the dispersion of the abnormal part in the visible light to near ultraviolet region, it is preferred to 4+ The content of is set within the above range.

[0153] 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 perspective of improving the desired Abbe number νd and the abnormal partial dispersion in the visible light to near ultraviolet region, it is preferred to 5+ The content of is set within the above range.

[0154] 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% in this order. 6+ The lower limit of the content of W is preferably 0%, and more preferably 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, and 1.6%. 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 abnormal partial dispersion in the visible light to near ultraviolet region, it is preferred to 6+ The content of is set within the above range.

[0155] 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 light to near ultraviolet region, it is preferred to 3+ The content of is set within the above range.

[0156] 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% in that order. 4+ The lower limit of the content of Zr is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5%. 4+ The content of Zr can be 0%. 4+ , which has the effect of improving chemical durability. However, if Zr 4+ If the content of Zr is too high, there is a risk of increasing the liquidus temperature LT and decreasing the solubility of the glass. 4+ The content of is set within the above range.

[0157] 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 that order. 5+ The lower limit of the content of Ta is preferably 0%, and more preferably 0.05%, 0.1%, and 0.5% in that order. 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. On the other hand, if Ta 5 + If the content of Ta is too high, there is a risk of increased raw material costs and a risk of decreased 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.

[0158] In the optical glass of the first embodiment, Ge 4+ The upper limit of the content of Ge is preferably 5%, and more preferably 4.5%, 4%, 3.5%, 3%, 2.5%, 2%, 1.5%, 1%, and 0.5%. 4+ The lower limit of the content of Ge is preferably 0%. 4+ The content can be 0%.

[0159] Ge 4+Ge has the function of improving the high dispersion characteristics of glass and is an especially expensive component among the commonly used glass components. Therefore, from the perspective of reducing the manufacturing cost of glass, it is preferred to use Ge 4+ The content of is set within the above range.

[0160] In the 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%.

[0161] In the 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%.

[0162] Sc 3+ , Hf 4+ It has the function of improving the high dispersion characteristics of glass, but it is an expensive component. 3+ , Hf 4+ The respective contents of are preferably within the above ranges.

[0163] In the 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%.

[0164] Lu 3+ It has the effect of improving the high dispersion characteristics of glass, and due to its high molecular weight, it is also a glass component that increases the specific gravity of glass. 3+ The content of is preferably within the above range.

[0165] The glass of the first embodiment preferably contains Si as an essential component. 4+ and B 3+ , Ca as an optional component 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.

[0166] The optical glass of the first embodiment includes O 2- As anionic component. 2- The upper limit of the content of is preferably 90 anions, and further more preferably 80 anions, 75 anions, 73 anions, 71 anions, 69 anions, 67 anions, 65 anions, 63 anions, 61 anions, 60 anions, 59 anions, 58 anions, 57 anions, 56 anions, 55 anions, 54 anions, 53 anions, 52 anions, 51 anions, 50 anions, 49 anions, 48 ​​anions, 47 anions, 46 anions, 45 anions, 44 anions, and 43 anions. In addition, 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%, 35 anion%, 36 anion%, 37 anion%, 38 anion%, 39 anion%, 40 anion%, and 41 anion%.

[0167] The optical glass of the first embodiment may contain O 2- and F - As components other than O 2- and F - Other anion components include Cl - Br - , I - However, Cl - Br - , I - The volatilization of these components will cause the characteristics of the glass to change, the homogeneity of the glass to decrease, and the loss of 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, and further preferably less than 0.25% anion. In addition, Br - 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 still more preferably 0% anion.

[0168] The glass of the first embodiment is preferably composed essentially of the above-mentioned glass components, and may contain other components within the range that does not impair the effects of the present invention.

[0169] In the optical glass of present embodiment, from the viewpoint that the transmittance near the suppression wavelength 360nm reduces, can add Sb ion.The upper limit of the content of Sb ion is preferably 1.0000 mass % with the addition ratio meter, further 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 %, 0.0050 mass %.In addition, the content of Sb ion is preferably more than 1.0 mass ppm with the addition ratio meter.It should be noted that 1.0 mass ppm is 0.0001 mass %. The lower limit of the Sb ion content is more preferably 0.0005 mass %, and further more preferably 0.0008 mass %, 0.0010 mass %, 0.0012 mass %, 0.0014 mass %, 0.0016 mass %, 0.0018 mass %, 0.0020 mass %, 0.0022 mass %, 0.0024 mass %, 0.0026 mass %, 0.0028 mass %, 0.0030 mass %, 0.0032 mass %, 0.0034 mass %, 0.0036 mass %, and 0.0038 mass %, in that order.

[0170] Sb ions can be added to the glass through, 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 perspective of suppressing the reduction of transmittance near a wavelength of 360nm, it is preferred to set the content of Sb ions to the above range. If the content of Sb ions is too much, Pt from the crucible is easily introduced into the glass, forming Pt colloid and producing Tyndall-like blur in the glass, which has the hidden danger of causing the light transmittance to deteriorate independently of the wavelength range. In addition, there is a hidden danger of the light transmittance of a specific wavelength being deteriorated due to the light absorption of the Sb ions themselves. In the case of no Sb ions or when the content of Sb ions is too low, the absorption of Pt ions near a wavelength of 360nm becomes significant. As a result, there is a hidden danger of the light transmittance of a specific wavelength being deteriorated in the wavelength range extending to visible light.

[0171] 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 ppm by mass, more preferably 0 to 80 ppm by mass, even more preferably 0 to 50 ppm by mass, and particularly preferably substantially absent.

[0172] 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%, still more preferably 0 to 0.001%, and particularly preferably substantially no Ga2O3, TeO2, and TbO2 are contained.

[0173] (Glass properties)

[0174] <Refractive Index nd>

[0175] In the optical glass of the first embodiment, the refractive index nd is preferably 1.55 to 1.80, and may be 1.56 to 1.75, 1.57 to 1.70, 1.58 to 1.65, 1.59 to 1.63, 1.60 to 1.62, or 1.58 to 1.60.

[0176] By appropriately adjusting the content of each glass component, the refractive index nd can be adjusted to a desired value. 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.

[0177] In the optical glass of the first embodiment, the refractive index nd and the Abbe number νd preferably satisfy the following formula [1-1].

[0178] nd≥(-0.0081×νd+2.1181)···〔1-1〕

[0179] 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.

[0180] nd≥(-0.0081×νd+2.1231)···〔1-2〕

[0181] nd≥(-0.0081×νd+2.1281)···〔1-3〕

[0182] nd≥(-0.0081×νd+2.1331)···〔1-4〕

[0183] nd≥(-0.0081×νd+2.1381)···〔1-5〕

[0184] <Relative partial dispersion Pg,F>

[0185] For 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.

[0186] In the optical glass of the first embodiment, it is preferable that the relative partial dispersion Pg,F satisfies the following formula [2-1].

[0187] Pg,F≥0.6200-0.0014×νd···〔2-1〕

[0188] 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.

[0189] Pg,F≥0.6220-0.0014×νd···〔2-2〕

[0190] Pg,F≥0.6240-0.0014×νd···〔2-3〕

[0191] Pg,F≥0.6260-0.0014×νd···〔2-4〕

[0192] Pg,F≥0.6280-0.0014×νd···〔2-5〕

[0193] Pg,F≥0.6300-0.0014×νd···〔2-6〕

[0194] In the optical element formed 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.

[0195] 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, or 0.0150. On the other hand, the lower limit of ΔPg,F is preferably -0.0100, and more preferably -0.0090, -0.0080, -0.0070, -0.0060, -0.0050, -0.0040, -0.0030, -0.0020, -0.0010, 0.0000, 0.0010, 0.0020, 0.0030, 0.0040, 0.0050, 0.0060, 0.0070, 0.0080, 0.0090, 0.0100, 0.0110, 0.0120, and 0.0130. By setting ΔPg,F within the above range, an optical glass suitable for compensating for high-order chromatic aberrations can be obtained.

[0196] The relative partial dispersion Pg,F is calculated using the above Schott dispersion equation.

[0197] In the present invention, the relative partial dispersion Pg,F is calculated as follows: Using the refractive index values ​​measured at the 12 different wavelengths (spectral lines) shown in Table A above, the coefficients of the wavelength term of the refractive index-wavelength relationship equation, known as the Schott dispersion equation, are fitted. Once these coefficients are determined, the dispersion equation is used for calculation. Using the refractive index values ​​measured at 12 different wavelengths allows the relative partial dispersion Pg,F to be calculated 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 result in less accuracy.

[0198] 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.

[0199] Pg,F=(ng-nF) / (nF-nC)

[0200] 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.

[0201] Pg,F(0)=0.6483-(0.001802×νd)

[0202] Furthermore, the deviation ΔPg,F of the relative partial dispersion Pg,F from the normal line is expressed as follows.

[0203] ΔPg,F=Pg,F-Pg,F(0)

[0204] <Specific Gravity of Glass>

[0205] 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.

[0206] 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+ Etc. The specific gravity can be controlled by appropriately adjusting the contents of these ingredients.

[0207] <Liquid phase temperature LT>

[0208] 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 of which the ribs caused by the erosion of glass melting equipment (for example, 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 content of all glass components. Among them, Si 4+ 、B 3+ 、Li + 、Na + , K + The content of Zr has a great influence on the liquidus temperature LT. 4+ 、Al 3+ When the content of etc. is high, the liquidus temperature rises.

[0209] 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 15-30 minutes. After cooling to below the glass transition temperature (Tg), the glass and the platinum crucible are placed in a melting furnace at a predetermined temperature and held for 2 hours. The temperature is set to an arbitrary value in 10°C increments. After holding for 2 hours, the glass is cooled and observed under a 100x optical microscope for the presence of crystals within the glass. This operation is repeated at each temperature, and the lowest temperature at which crystallization does not occur is defined as the liquidus temperature.

[0210] <Glass transition temperature Tg>

[0211] The upper limit of the glass transition temperature Tg of the optical glass of the first embodiment is preferably 600°C, and more preferably 580°C, 560°C, 540°C, 520°C, 510°C, 500°C, 490°C, 480°C, 470°C, 460°C, 450°C, 440°C, and 430°C. 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, and 420°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. If the glass transition temperature Tg is too high, there is a risk that precision press molding may not be possible.

[0212] The component that relatively lowers the glass transition temperature Tg is F - 、Li + 、Na + , K +The component that relatively increases the glass transition temperature Tg is Si 4+ 、La 3+ 、Zr 4+ 、Nb 5+ The glass transition temperature Tg can be controlled by appropriately adjusting the contents of these components.

[0213] <Light Transmittance of Glass>

[0214] The light transmittance of the optical glass of the first embodiment can be evaluated based on the coloration degrees λ80, λ70, and λ5.

[0215] 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. The wavelength at which the external transmittance reached 80% was designated as λ80, the wavelength at which the external transmittance reached 70% was designated as λ70, and the wavelength at which the external transmittance reached 5% was designated as λ5.

[0216] 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.

[0217] <Mechanical properties Knoop hardness Hk>

[0218] 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, and 480, 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, lapping, and cutting to manufacture lenses. The upper limit of the Knoop hardness Hk is not particularly limited, but is generally 750, preferably 600.

[0219] Knoop hardness Hk can be adjusted by La 3+ 、Gd 3+ 、Y 3+ 、Si 4+ 、Zr 4+ 、Al 3+ to increase the content.

[0220] <ΔT360>

[0221] In the optical glass of this embodiment, when the thickness is set to 10.0mm±0.1mm, the upper limit of the difference (ΔT360) between the external transmittance at a wavelength of 700nm and the external transmittance at a wavelength of 360nm is preferably 31.0%, and further 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 and is generally 2~30%. ΔT360 can be adjusted by introducing Sb ions. In addition, in the present application, in order to provide a glass with low dispersion, it is not preferred in principle to use high dispersion components such as Ti, Nb, W, and Bi. When these are introduced for purposes such as high anomalous dispersion, ΔT360 will increase. By setting ΔT360 within the above range, a decrease in transmittance around a wavelength of 360 nm can be suppressed.

[0222] External transmittance is defined as the ratio of the transmitted light intensity to the incident light intensity when light is incident along the thickness of the glass sample [transmitted light intensity / incident light intensity × 100]. Note that external transmittance also includes light reflection losses at the sample surface.

[0223] (Manufacture of optical glass)

[0224] The glass of the first embodiment is prepared by mixing glass raw materials in a manner to achieve the above-mentioned given composition, and the prepared glass raw materials are used to produce the 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 or the like 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, heated, and remelted to produce molten glass. After further clarification and homogenization, the molten glass is formed and slowly cooled to produce optical glass. The forming and slow cooling of the molten glass can be carried out by known methods.

[0225] 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.

[0226] (Manufacture of glass materials for press molding)

[0227] According to one embodiment of the present invention, there are provided a press-molding glass material formed of the optical glass of the first embodiment and a method for producing the same.

[0228] 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.

[0229] 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.

[0230] 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.

[0231] The glass raw material for press molding of the first embodiment is formed of an 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 the present 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.

[0232] (Manufacturing of Optical Element Blanks)

[0233] 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).

[0234] (Manufacturing of optical components)

[0235] 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.

[0236] 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.

[0237] The optical element of the first 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.

[0238] Second embodiment

[0239] In the oxide optical glass of the second embodiment,

[0240] The Abbe number νd is 62.00 or more,

[0241] B3+ The content of cations is greater than 0% and less than 50.00%.

[0242] F - The content of anion is greater than 0% and less than 85%.

[0243] La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 5 cation % or more,

[0244] 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 0.60 or more,

[0245] Si 4+and B 3+ The total content relative to Si 4+ 、B 3+ and P 5+ The total content of cation ratio [(Si 4+ +B 3+ ) / (Si 4 + +B 3+ +P 5+ )] is above 0.2.

[0246] <Abbe number νd>

[0247] In the optical glass of the second embodiment, the Abbe number νd is 62.00 or greater. The Abbe number νd is preferably 62 to 75, and may be 62.2 to 73, 62.4 to 71, 62.6 to 69, 62.8 to 68, 63 to 67, or 62 to 63. The Abbe number νd is calculated in the same manner as in the first embodiment.

[0248] The Abbe number νd can be adjusted to a desired value by appropriately adjusting the content of each glass component. The component that relatively reduces the Abbe number νd, i.e., the high dispersion component, is Nb 5+ 、Ti 4+ 、Zr 4+ 、W 6+ 、Bi 3+ 、Ta 5+ On the other hand, the component that relatively increases the Abbe number νd, that is, the low dispersion component is F - 、Si 4+ 、B 3+ 、Li + 、Na + , K + 、La 3+ 、Ba 2+ , Ca 2+ 、Sr 2+ wait.

[0249] 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%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, and 21%. 3+The upper limit of the content is preferably 45.00%, and more preferably 40.00%, 39.00%, 38.00%, 37.00%, 36.00%, 35.00%, 34.00%, 33.00%, 32.00%, 31.00%, 30.00%, 29.00%, 28.00%, 27.00%, 26.00%, 25.00%, 24.00%, and 23.00%.

[0250] B 3+ It is a network forming component of glass. 3+ The chemical durability can be improved by setting the content of B to 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+ If the content is too high, there is a risk of increased volatilization of glass components and a risk of decreased thermal stability and chemical durability of the glass.

[0251] The optical glass of the second embodiment includes F - As anionic component. - The content of anion is greater than 0% and less than 85%. - The lower limit of the content of is preferably 5 anions, and further preferably 10 anions, 15 anions, 20 anions, 24 anions, 27 anions, 30 anions, 33 anions, 35 anions, 37 anions, 39 anions, 41 anions, 43 anions, 45 anions, 46 anions, 47 anions, 48 ​​anions, 49 anions, 50 anions, 51 anions, 52 anions, 53 anions, 54 anions, 55 anions, 56 anions, and 57 anions. In addition, F - The upper limit of the content of is preferably 80 anions, and further more preferably 77 anions, 75 anions, 73 anions, 71 anions, 69 anions, 67 anions, 65 anions, 64 anions, 63 anions, 62 anions, 61 anions, 60 anions, 59 anions. - When the content of F is set within 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. - If the content is too high, there is a hidden danger of increased volatilization of glass components.

[0252] 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 5% or more. The lower limit of this total content is preferably 10%, and further preferably 15%, 20%, 25%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38% in sequence. In addition, the upper limit of this total content is preferably 60%, and further more preferably 55%, 50%, 48%, 46%, 45%, 44%, 43%, 42%, 41% in sequence. By setting this total content to the above range, an optical glass with a high refractive index nd can be obtained. On the other hand, if this total content is too little, there is a hidden danger that the desired optical constants cannot be obtained. If this total content is too much, there is a hidden danger that the thermal stability of the glass decreases.

[0253] 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+ +Nb5+ +W 6+ +Bi 3+ +Zr 4+ +Ta 5+ )] is 0.60 or more. The lower limit of the cation ratio is preferably 0.70, and more preferably 0.80, 0.90, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, 1.90, 1.95, 2.00, 2.05, 2.10, 2.15, and 2.20. The upper limit of the cation ratio is preferably 4, and more preferably 3.8, 3.6, 3.4, 3.2, 3.0, 2.9, 2.8, 2.7, 2.65, 2.60, 2.55, 2.50, 2.40, 2.35, 2.30, and 2.25. 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 of increased volatilization of glass components. In addition, if the cation ratio is too high, there is a risk of decreased thermal stability of the glass.

[0254] In the optical glass of the second embodiment, Si 4+ and B 3+ The total content relative to Si 4+ 、B 3+ and P 5+ The total content of cation ratio [(Si 4+ +B 3+ ) / (Si 4+ +B 3+ +P 5+ )] is 0.2 or greater. The lower limit of the cation ratio is preferably 0.3, and more preferably 0.4, 0.5, 0.6, 0.7, 0.8, 0.85, 0.9, or 0.95. Furthermore, the upper limit of the cation ratio is preferably 1, and more preferably 0.99, 0.98, or 0.97. The cation ratio may be 1. By setting the cation ratio within the above range, an optical glass having excellent chemical durability and mechanical properties can be obtained.

[0255] In the optical glass of the second embodiment, the contents and ratios of the glass components other than those described above can be the same as those of the first embodiment.

[0256] In addition, in the optical glass of the second embodiment, the glass properties can be made the same as those of the first embodiment.

[0257] Furthermore, 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 may be the same as in the first embodiment.

[0258] Example

[0259] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the embodiments shown in the Examples.

[0260] (Example 1)

[0261] Glass samples having the glass compositions shown in Tables 1 to 9 were prepared by the following procedures, and various evaluations were performed.

[0262] [Manufacturing of optical glass]

[0263] First, oxides, fluorides, hydroxides, carbonates, nitrates, composite oxides, fluorosilicates, and fluoroborates corresponding to the constituent components of the glass are prepared as raw materials. These raw materials are weighed and blended in such a manner that the resulting optical glass has the compositions shown in Table 1, and the raw materials are thoroughly mixed. The resulting blended raw materials (batch raw materials) are placed in a platinum crucible and heated at 1150-1250°C for 1.5-3 hours to form a molten glass. The resulting mixture is stirred to homogenize and clarify the mixture, and then the molten glass is cast into a mold preheated to an appropriate temperature. The cast glass is heat treated at a temperature near its glass transition temperature (Tg) for 30 minutes and then naturally cooled to room temperature in a furnace to obtain a glass sample.

[0264] In Table 1 (1) to (9), the content of glass components not shown is 0.00% cation %. For example, in any glass sample, Rb + 、Cs + And Ge 4+ The content of each is 0.00 cation %.

[0265] [Ratio of the number of anions to the number of cations]

[0266] The ratio of the number of anions to the number of cations (anion number / cation number) is the molar ratio of the total number of anions to the total number of cations and can be calculated based on the composition. Specifically, the sum of the positive charges of each cation when the total number of cations is set to 100 (an arbitrary constant) is calculated, and then the negative charge of the anions that form the same number and the molar percentage of anions are combined to calculate the total number of anions when the total number of cations is set to 100. Based on this calculated value, the ratio of the number of anions to the number of cations (anion number / cation number) is calculated.

[0267] [Measurement of optical properties]

[0268] The resulting glass sample was further annealed near its glass transition temperature (Tg) for approximately 30 minutes to approximately 2 hours, then cooled to room temperature in a furnace at a rate of -30°C / hour to obtain an annealed sample. The annealed sample was measured for its refractive index, Abbe number νd, relative partial dispersion Pg,F, ΔPg,F, specific gravity, glass transition temperature (Tg), liquidus temperature (LT), λ80, λ70, λ5, and ΔT360. The results are shown in Table 2.

[0269] (i) Refractive index nd, ng, nF, nC, Abbe number νd and relative partial dispersion Pg,F

[0270] The refractive index of the annealed sample was measured at the 12 wavelengths shown in Table A in accordance with Japanese Industrial Standard (JIS) JIS B 7071-1 Optical Glass - Determination of Refractive Index - Part 1: Minimum Deviation Angle Method.

[0271] Next, the refractive indices of each ray obtained through measurement were substituted into the Schott dispersion equation specified in Appendix B of JIS B7071-1, Optical Glass - Determination of Refractive Index - Part 1: Minimum Deviation Angle Method, and the constants of the Schott dispersion equation were determined using the least squares method. The Abbe number νd and the relative partial dispersion Pg,F were then calculated using the Schott dispersion equation with the determined constants.

[0272]

[0273] Schott dispersion type: n 2 =a0+a1λ 2 +a2λ -2 +a3λ -4 +a4λ -6 +a5λ -8

[0274] Where n is the refractive index, λ is the wavelength (μm), and a0, a1, a2, a3, a4, and a5 are constants.

[0275] It should be noted that the refractive index nd refers to the refractive index at a wavelength of 587.56 nm.

[0276] The Abbe number νd is expressed as follows using the refractive indices nd, nF, and nC of d-rays, F-rays, and C-rays, respectively.

[0277] νd=(nd-1) / (nF-nC)

[0278] The relative partial dispersion Pg,F is expressed as follows using the refractive indices ng, nF, and nC of g-rays, F-rays, and C-rays, respectively.

[0279] Pg,F=(ng-nF) / (nF-nC)

[0280] (ii) ΔPg,F

[0281] 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 Pg,F(0) is expressed by the following equation.

[0282] Pg,F(0)=0.6483-(0.001802×νd)

[0283] The deviation ΔPg,F of the relative partial dispersion Pg,F from the normal line is calculated based on the following formula.

[0284] ΔPg,F=Pg,F-Pg,F(0)

[0285] (iii) Specific gravity

[0286] The specific gravity was measured by the Archimedes method.

[0287] (iv) Glass transition temperature Tg

[0288] The glass transition temperature Tg was measured using a differential scanning calorimeter (DSC3300SA) manufactured by NETZSCH JAPAN CO., LTD. at a heating rate of 10° C. / min.

[0289] (v) Liquidus temperature LT

[0290] The glass was placed in a furnace heated to a given temperature and held there for approximately two hours. After cooling, the interior of the glass was observed using an optical microscope at 40-100x magnification, and the liquidus temperature was determined based on the presence or absence of crystallization.

[0291] (vi) λ80, λ70, λ5

[0292] The annealed sample was processed to a thickness of 10 mm with parallel, optically polished surfaces, and its spectral transmittance was measured over a wavelength range of 280 nm to 700 nm. The intensity of light perpendicularly incident on one optically polished surface was defined as intensity A, and the intensity of light emitted from the other surface was defined as intensity B. The spectral transmittance (B / A) was calculated. The wavelength at which the spectral transmittance reached 80% was designated as λ80, the wavelength at which the spectral transmittance reached 70% as λ70, and the wavelength at which the spectral transmittance reached 5% as λ5. It should be noted that the spectral transmittance also includes light reflection losses from the sample surface.

[0293] (vii) ΔT360

[0294] The annealed sample was processed to a thickness of 10.0 mm ± 0.1 mm with parallel, optically polished flat surfaces. External transmittance at wavelengths of 700 nm and 360 nm was measured. The difference between the external transmittance at a wavelength of 700 nm (T700) and the external transmittance at a wavelength of 360 nm (T360) was calculated as ΔT360.

[0295] External transmittance is defined as the ratio of the transmitted light intensity to the incident light intensity when light is incident along the thickness of the 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.

[0296] [Mechanical properties Knoop hardness Hk]

[0297] The obtained glass samples were processed to have parallel, optically polished surfaces with a thickness of 2 mm to 20 mm. The Knoop hardness Hk was measured according to the Japan Optical Glass Industry Association standard JOGIS-09. Specifically, a knob was pressed into the processed glass sample, and the Knoop hardness Hk was measured based on the size of the indentation. The results are shown in Tables 2(1) and (2).

[0298]

[0299]

[0300]

[0301]

[0302]

[0303]

[0304]

[0305]

[0306]

[0307] (Example 2)

[0308] Using each optical glass produced in Example 1, lens blanks were produced by a known method, and the lens blanks were processed by a known method such as grinding to produce various lenses.

[0309] The optical lenses produced include various lenses such as biconvex lenses, biconcave lenses, plano-convex lenses, plano-concave lenses, concave meniscus lenses, and convex meniscus lenses.

[0310] By combining the various lenses produced above with lenses made of glass with a smaller Abbe number than the lenses themselves, such as flint glass, high-order chromatic aberrations in the near-ultraviolet to visible light regions can be compensated well.

[0311] It should be understood that the embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims, not by the foregoing description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0312] For example, the optical glass of one embodiment of the present invention can be produced by adjusting the composition described in the specification with respect to the glass composition exemplified above.

[0313] Furthermore, it is of course possible to arbitrarily combine two or more items described as examples or preferred ranges in the specification.

Claims

1. An optical glass, wherein: The Abbe number νd is 62.00 or more, B 3+ The content of cations is greater than 0% and less than 50.00%. Si 4+ The content of cations is greater than 0%, F - The content of anions is greater than 0%, La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 5 cation % or more.

2. The optical glass according to claim 1, wherein 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.

50.

3. An optical glass, wherein: The Abbe number νd is 62.00 or more, B 3+ The content of cations is greater than 0% and less than 50.00%. F - The content of anion is greater than 0% and less than 85%. La 3+ 、Gd 3+ and Y 3+ The total content [La 3+ +Gd 3+ +Y 3+ ] is 5 cation % 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 0.60 or more, Si 4+ and B 3+ The total content relative to Si 4+ 、B 3+ and P 5+ The total content of cation ratio [(Si 4+ +B 3+ ) / (Si 4+ +B 3+ +P 5+ )] is above 0.

2.

4. The optical glass according to any one of claims 1 to 3, wherein The content of Sb ions is 1.0 mass ppm or more in terms of added proportion.

5. The optical glass according to any one of claims 1 to 3, wherein 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. 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 3.

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