TW202404916A - Optical glass and optical component which has a low glass transition temperature, low dispersion, and excellent thermal stability - Google Patents

Abstract

The present invention provides an optical glass that has a low glass transition temperature, low dispersion, and excellent thermal stability. The optical glass of this invention has the following glass composition as expressed in cation%: the S<SP>6+<SP> content is more than 0.0% and 30.0% or less, the Al<SP>3+<SP> content is more than 0.0% and 30.0% or less, the P<SP>5+<SP> content is 5.0% or more and 50.0% or less, the Li<SP>+<SP> content is 0.0% or more and 51.0% or less, the Na<SP>+<SP> content is 0.0% or more and 44.0% or less, the K<SP>+<SP> content is 0.0% or more and 45.0% or less, the total content R<SP>+<SP> of Li<SP>+<SP>, Na<SP>+<SP>, K<SP>+<SP> and Cs<SP>+<SP> is 5.0% or more, the total content of Be<SP>2+<SP>, Mg<SP>2+<SP>, Ca<SP>2+<SP>, Sr<SP>2+<SP> and Ba<SP>2+<SP> is R<SP>2+<SP>, the cation ratio of R<SP>2+<SP> to the total content of Al<SP>3+<SP> and R<SP>2+<SP> (R<SP>2+<SP>/(Al<SP>3+<SP>+R<SP>2+<SP>)) is 0.56 or less. The optical glass of this invention has the following glass composition as expressed in anion%: the O<SP>2-<SP> content is 10.0% or more and 95.0% or less, the F<SP>-<SP> content is 10.0% or more and 90.0% or less, and the external transmittance of the optical glass at a wavelength of 500 nm to 1000 nm is 80% or more when converted to a thickness of 10.0 mm.

Description

Optical glass and optical components

The present invention relates to optical glass and optical components.

For example, Patent Document 1 discloses optical glass with a low glass transition temperature. [Prior art documents] [Patent Document]

Patent document 1: WO2003/037813

[Problem to be solved by the invention]

Glass with a low glass transition temperature can be molded at low temperatures, and it is preferable to be moldable at low temperatures from the viewpoint of less deterioration of the mold due to heating and the ability to use a mold with low heat resistance and low price.

In projection optical systems such as imaging optical systems and projectors, by combining lenses with different dispersions to form a cemented lens, chromatic aberration can be compensated and the optical system can be miniaturized. Low dispersion is generally easily achieved with plastic lenses. Therefore, optical glass with low dispersion is useful as a material for optical elements constituting imaging optical systems and projection optical systems such as projectors.

In view of the above, the inventors of the present invention conducted research on optical glass having a low glass transition temperature and low dispersion, and found that further improvements in thermal stability are expected.

An object of one embodiment of the present invention is to provide optical glass with a low glass transition temperature, low dispersion, and excellent thermal stability. [Means used to solve problems]

One embodiment of the present invention relates to an optical glass in which the S ⁶⁺ content exceeds 0.0 cation % and is 30.0 cation % or less, and the Al ³⁺ content exceeds 0.0 cation % and is 30.0 cation % in the glass composition expressed as cation %. Below, the P ⁵⁺ content is 5.0 cation % or more and 50.0 cation % or less, the Li ⁺ content is 0.0 cation % or more and 51.0 cation % or less, the Na ⁺ content is 0.0 cation % or more and 44.0 cation % or less, and the K ⁺ content is 0.0 Cation % or more and 45.0 cation % or less, the total content R ⁺ of Li ⁺ , Na ⁺ , K ⁺ and Cs ⁺ is 5.0 cation % or more, Be ²⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ and Ba ² Let the total content of ⁺ be R ²⁺ , and the cation ratio of R ²⁺ to the total content of Al ³⁺ and R ²⁺ (R ²⁺ /(Al ³⁺ +R ²⁺ )) is 0.56 or less, in terms of anion % In the glass composition represented, the O ^2- content is 10.0 anion % or more and 95.0 anion % or less, the F ^- content is 10.0 anion % or more and 90.0 anion % or less, and the external transmittance conversion of the optical glass at the above wavelength 500 nm ~ 1000 nm When the thickness is 10.0mm, it is more than 80%.

By having the above-mentioned glass composition, the optical glass can have a low glass transition temperature and low dispersion, and can exhibit excellent thermal stability. [Effects of the invention]

According to one embodiment of the present invention, it is possible to provide optical glass with a low glass transition temperature, low dispersion, and excellent thermal stability. In addition, according to one embodiment of the present invention, an optical element including the optical glass can be provided.

[Optical Glass] In the present invention and this specification, unless otherwise specified, the content and total content of cationic components are expressed in cation %, and unless otherwise specified, the content and total content of anionic components are expressed in anion %. Here, "% of cations" is a value calculated as "(number of cations of interest/total number of cations in the glass component)×100" and represents the amount of cations of interest relative to the total amount of cation components. Mol%. In addition, "% of anions" is a value calculated as "(number of anions of interest/total number of anions in the glass component) × 100" and represents the amount of anions of interest relative to the total amount of anion components. Mol%. The molar ratio of the contents between the cationic components is equal to the ratio of the contents expressed in % cations of the cationic components of interest. The content of each component can be quantified by known methods, such as inductively coupled plasma optical emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), ion chromatography, and the like. Cationic components are represented by, for example, Al ³⁺ and P ⁵⁺ . The valence of the cationic component (for example, the valence of Al ³⁺ is +3 and the valence of P ⁵⁺ is +5) is a value determined by custom. It is the same as expressing Al, P, etc. as Al ₂ O ₃ , P ₂ O ₅ , etc. on an oxide basis. Regarding the component represented by _{Am On} on an oxide basis (A represents a cation, O represents oxygen, m and n are stoichiometrically determined integers), the cation A is represented by As ⁺ , where s=2n/m. Therefore, for example, when analyzing and quantifying the glass composition, it is not necessary to analyze the valence of the cationic component. The above points are the same for anionic components. When analyzing and quantifying the glass composition, the valence of the anionic component does not need to be analyzed. In addition, in the present invention and this specification, the content of a constituent component is 0.0%, 0.00%, does not contain, or is not introduced, which means that the constituent component is not substantially included, and the content of the constituent component is below the impurity level. The impurity level Below means, for example, less than 0.01%.

In the present invention and this specification, "thermal stability" refers to the degree to which crystals are less likely to precipitate when molten glass solidifies.

Hereinafter, the glass transition temperature may be expressed as Tg.

Hereinafter, the above-mentioned optical glass (sometimes simply referred to as "glass") will be described in more detail.

＜Glass composition＞ Hereinafter, the glass composition expressed in cation % of the above-mentioned optical glass will be described.

From the viewpoint of lowering the Tg of the glass, maintaining the refractive index and low dispersion, and improving the thermal stability, the S ⁶⁺ content exceeds 0%, preferably 0.5% or more, 1.0% or more, 1.2% or more, 1.3% Above, above 1.4%, above 1.5%, above 1.6%, above 1.7%, above 1.8%, above 1.9%, above 2.0%, above 2.1%, above 2.2%, above 2.3%, above 2.4%, above 2.5%, The order of more than 2.6%, more than 2.7%, more than 2.8%, more than 2.9%, and more than 3.0% is better. In addition, from the viewpoint of maintaining the refractive index, maintaining thermal stability, and suppressing an increase in liquidus temperature, the S ⁶⁺ content is 30.0% or less, preferably 29.0% or less, 28.0% or less, 27.0% or less, 26.0% or less, 25.0% or less, 24.0% or less, 23.0% or less, 22.0% or less, 21.0% or less, 20.0% or less, 19.0% or less, 18.0% or less, 17.0% or less, 16.0% or less, 15.0% or less, 14.0% or less. good.

From the viewpoint of increasing the refractive index and maintaining low dispersion, as well as improving the thermal stability of the glass and maintaining chemical durability, the Al ³⁺ content exceeds 0.0%, preferably 1.0% or more, 2.0% or more, 3.0 The order of more than %, more than 4.0%, more than 5.0%, more than 6.0%, more than 7.0%, more than 8.0%, more than 9.0%, more than 10.0%, more than 11.0% is better. In addition, from the viewpoint of suppressing an increase in Tg, the Al ³⁺ content is 30.0% or less, preferably 29.0% or less, 28.0% or less, 27.0% or less, 26.0% or less, 25.0% or less, 24.0% or less, 23.0% or less. The order of , 22.0% or less, 21.0% or less, 20.0% or less, 19.0% or less, 18.0% or less is better.

From the viewpoint of maintaining low dispersion and improving the thermal stability of the glass, the P ⁵⁺ content is 5.0% or more, preferably 7.0% or more, 9.0% or more, 11.0% or more, 13.0% or more, 14.0% or more, 15.0% or more. The order of above %, above 16.0%, and above 17.0% is better. In addition, from the viewpoint of maintaining the refractive index, improving the thermal stability of the glass, and suppressing a decrease in chemical durability, the P ⁵⁺ content is 50.0% or less, preferably 48.0% or less, 46.0% or less, 44.0% or less, and 42.0%. The order of below, below 40.0%, below 38.0%, below 37.0%, below 36.0%, below 35.0%, below 34.0%, below 33.0%, below 32.0% is better.

From the viewpoint of increasing the refractive index and maintaining low dispersion, and from the viewpoint of lowering the Tg of the glass, improving the meltability of the glass, and lowering the specific gravity, the Li ⁺ content is 0.0% or more, preferably 1.0% or more, and 2.0 % or more, 4.0% or more, 5.5% or more, 7.0% or more, 8.5% or more, 10.0% or more, 12.0% or more, 13.5% or more, 15.0% or more, 16.5% or more, 17.0% or more, 18.5% or more, 20.0% or more order is better. In addition, from the viewpoint of improving the thermal stability of the glass and suppressing a decrease in chemical durability, the Li ⁺ content is 51.0% or less, preferably 48.0% or less, 45.0% or less, 43.0% or less, 41.0% or less, 40.0% or less. , below 39.0%, below 38.0%, below 37.0%, below 36.0%, below 35.0%, below 34.0%, below 33.0%, below 32.0%, below 31.0% in the order of better.

From the viewpoint of maintaining the refractive index, maintaining low dispersion, lowering the Tg of the glass, improving the meltability of the glass, and lowering the specific gravity, the Na ⁺ content is 0.0% or more, preferably 1.0% or more, and 2.0% or more, 3.0 The order of above %, above 4.0%, above 5.0%, above 6.0%, above 7.0%, above 8.0%, above 9.0% is better. In addition, from the viewpoint of improving the thermal stability of the glass and suppressing a decrease in chemical durability, the Na ⁺ content is 44.0% or less, preferably 42.0% or less, 40.0% or less, 38.0% or less, 36.0% or less, 34.0% or less. , below 32.0%, below 30.0%, below 28.0%, below 26.0%, below 24.0%, below 22.0%, below 20.0%, below 19.0% in the order of better.

From the viewpoint of maintaining the refractive index, maintaining low dispersion, lowering the Tg of the glass, improving the meltability of the glass, and lowering the specific gravity, the K ⁺ content is 0.0% or more, preferably 1.0% or more, and 2.0% or more, 3.0 The order of % or more, 4.0% or more, 5.0% or more, and 6.0% or more is better. In addition, from the viewpoint of improving the thermal stability of the glass, suppressing the decrease in chemical durability, and reducing the specific gravity, the K ⁺ content is 45.0% or less, 43.0% or less, 40.0% or less, 38.0% or less, 36.0% or less, 34.0% Below, below 32.0%, below 30.0%, below 28.0%, below 26.0%, below 25.0%, below 24.0%, below 23.0%, below 22.0%, below 21.0%, below 20.0%, below 19.0%, below 18.0%, The order of 17.0% or less, 16.0% or less, and 15.0% or less is better.

From the viewpoint of maintaining low dispersion, lowering the Tg and specific gravity of the glass, and lowering the liquidus temperature, the total content R ⁺ of Li ⁺ , Na ⁺ , K ⁺ and Cs ⁺ is 5.0% or more, preferably 10.0% More than 15.0%, more than 20.0%, more than 23.0%, more than 25.0%, more than 28.0%, more than 30.0%, more than 33.0%, more than 35.0%, more than 37.0%, more than 40.0%, more than 42.0% is better in this order . In addition, from the viewpoint of maintaining low dispersion, maintaining the thermal stability of the glass, and suppressing a decrease in chemical durability, the total content R ⁺ of Li ⁺ , Na ⁺ , K ⁺ and Cs ⁺ is preferably 65.0% or less, preferably 64.0% The order of below, below 63.0%, below 62.0%, below 61.0%, below 60.0%, below 59.0% is better.

The Cs ⁺ content may be 0.0%, or more than 0.0%, or more than 0.0%. From the viewpoint of lowering the Tg of the glass and improving the meltability of the glass, the Cs ⁺ content can be 0.0% or more, preferably 0.1% or more, 0.2% or more, 0.3% or more, 0.4% or more, 0.5% or more, 0.6 The order of % or above is better. In addition, from the viewpoint of improving the thermal stability of the glass and suppressing a decrease in chemical durability, the Cs ⁺ content is preferably 10.0% or less, 8.0% or less, 6.0% or less, 4.0% or less, 2.0% or less, 1.5% or less, Orders below 1.0% are better.

From the viewpoint of suppressing the increase in Tg and maintaining the thermal stability of the glass, the total content of Be ²⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ and Ba ²⁺ is set to R ²⁺ . In the above optical glass , the cation ratio of R ²⁺ to the total content of Al ³⁺ and R ²⁺ (R ²⁺ /(Al ³⁺ + R ²⁺ )) is 0.56 or less, preferably 0.55 or less, 0.54 or less, 0.53 or less, 0.52 or less, 0.51 or less, 0.50 or less, 0.49 or less, 0.48 or less, 0.47 or less, 0.46 or less, 0.45 or less, 0.44 or less, 0.43 or less, 0.42 or less, 0.41 or less, 0.40 or less, 0.39 or less, 0.38 or less, 0.37 or less, in order. good. In addition, the cation ratio (R ²⁺ /(Al ³⁺ + R ²⁺ )) may be 0.00 or more or more than 0.00. From the viewpoint of lowering the Tg of the glass and improving the meltability of the glass, it is preferably 0.01 or more, and 0.02 is preferred. The order of above and above 0.03 is better.

The Be ²⁺ content may be 0.0%, more than 0.0%, or more than 0.0%. From the viewpoint of maintaining the refractive index, maintaining low dispersion, suppressing an increase in Tg, and maintaining the thermal stability of the glass, the Be ²⁺ content is preferably 15.0% or less, more preferably 10.0% or less, and 5.0% or less, 2.5% or less. The order of below, 1.5% or below, 1.0% or below, and 0.5% or below is further preferred. The Mg ²⁺ content may be 0.0%, more than 0.0%, or more than 0.0%. From the viewpoint of maintaining the refractive index, maintaining low dispersion, suppressing an increase in Tg, and maintaining the thermal stability of the glass, the Mg ²⁺ content is preferably 15.0% or less, more preferably 14.0% or less, and 13.0% or less, 12.0% or less. The order of below, 11.0% or below, and 10.0% or below is even more preferable. The Ca ²⁺ content can be 0.0%, more than 0.0%, or more than 0.0%. From the viewpoint of maintaining the refractive index, maintaining low dispersion, suppressing an increase in Tg, and maintaining the thermal stability of the glass, the Ca ²⁺ content is preferably 15.0% or less, more preferably 14.0% or less, and 13.0% or less, 12.0% or less. The order of below, 11.0% or below, 10.0% or below, 9.0% or below, 8.0% or below, 7.0% or below, 6.0% or below, and 5.0% or below is further preferred. The Sr ²⁺ content may be 0.0%, more than 0.0%, or more than 0.0%. From the viewpoint of maintaining the refractive index, maintaining low dispersion, suppressing an increase in Tg, and maintaining the thermal stability of the glass, the Sr ²⁺ content is preferably 10.0% or less, more preferably 9.0% or less, and 8.0% or less, 7.0% or less. The order of below, 6.0% or below, 5.0% or below, and 4.0% or below is further preferred. The Ba ²⁺ content may be 0.0%, more than 0.0%, or more than 0.0%. From the viewpoint of maintaining the refractive index, maintaining low dispersion, improving the meltability of the glass, suppressing an increase in Tg, and maintaining the thermal stability of the glass, the Ba ²⁺ content is preferably 10.0% or less, more preferably 9.0% or less. The order of 8.0% or less, 7.0% or less, 6.0% or less, 5.0% or less, 4.0% or less, 3.0% or less, and 2.0% or less is further preferred. The total content R ²⁺ of Be ²⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ and Ba ²⁺ may be 0.0%, 0.0% or more, or more than 0.0%. From the viewpoint of maintaining the refractive index, maintaining low dispersion, suppressing an increase in Tg, and maintaining the thermal stability of the glass, the total content R ²⁺ is preferably 20.0% or less, more preferably 19.0% or less, and 18.0% or less, 17.0% or less. % or less, 16.0% or less, 15.0% or less, 14.0% or less, 13.0% or less, 12.0% or less, 11.0% or less, and 10.0% or less are more preferred in this order.

The Zn ²⁺ content may be 0.0%, more than 0.0%, or more than 0.0%. Zn ²⁺ plays a role in maintaining the refractive index and improving thermal stability, but if contained in excess, dispersion tends to increase. From the above point of view, the Zn ²⁺ content is preferably 20.0% or less, more preferably 19.0% or less, 18.0% or less, 17.0% or less, 16.0% or less, 15.0% or less, 14.0% or less, 13.0% or less, 12.0% The order of below, 11.0% or below, and 10.0% or below is even more preferable.

The Zr ⁴⁺ content can be 0.0%, more than 0.0%, or more than 0.0%. Zr ⁴⁺ is a component that increases the refractive index, but if contained in excess, dispersion tends to increase and Tg tends to increase. From the above point of view, the Zr ⁴⁺ content is preferably 10.0% or less, more preferably 9.0% or less, 8.0% or less, 7.0% or less, 6.0% or less, 5.0% or less, 4.0% or less, 3.0% or less, 2.0% The following order is even better.

Cation ratio of the P ⁵⁺ content to the total content of Al ³⁺ and P ⁵⁺ from the viewpoint of maintaining low dispersion, further improving the thermal stability of the glass, further lowering the Tg of the glass, and improving the meltability of the glass (P ⁵⁺ /(Al ³⁺ +P ⁵⁺ )) is preferably 0.30 or more, more preferably 0.35 or more, and more preferably 0.40 or more, 0.45 or more, and 0.50 or more in this order. In addition, from the viewpoint of maintaining the refractive index and maintaining chemical durability, the cation ratio (P ⁵⁺ /(Al ³⁺ +P ⁵⁺ )) is preferably 0.85 or less, more preferably 0.83 or less, and 0.81 or less, 0.80 or less, The order of 0.79 or less, 0.78 or less, 0.77 or less, 0.76 or less, 0.75 or less, 0.74 or less, 0.73 or less, 0.72 or less, and 0.71 or less is more preferable.

From the viewpoint of increasing the refractive index, further lowering the Tg of the glass, and improving the meltability of the glass, the cation ratio of the Li ⁺ content to the total of R ⁺ and R ²⁺ (Li ⁺ /(R ⁺ ＋R ²⁺ )) More preferably 0.00 or more, more preferably 0.05 or more, 0.10 or more, 0.13 or more, 0.15 or more, 0.17 or more, 0.20 or more, 0.23 or more, 0.25 or more, 0.27 or more, 0.30 or more, 0.33 or more, 0.35 or more, 0.37 or more, 0.40 The above order is even better. In addition, from the viewpoint of further lowering the Tg of the glass and improving the meltability of the glass, the cation ratio (Li ⁺ /(R ⁺ +R ²⁺ )) is preferably 1.00 or less, more preferably 0.95 or less, and 0.92 or less, 0.90 The following order is more preferable: 0.88 or less, 0.85 or less, 0.83 or less, 0.80 or less, 0.78 or less, 0.75 or less, 0.72 or less, 0.70 or less, 0.67 or less, 0.65 or less, 0.63 or less, and 0.60 or less.

From the viewpoint of maintaining low dispersion, further lowering the Tg of the glass, improving the meltability of the glass, and lowering the specific gravity, the cation ratio of R ⁺ to the total content of Al ³⁺ and P ⁵⁺ (R ⁺ /(Al ^{3 +} ＋P ⁵⁺ )) More preferably 0.93 or more, more preferably 0.95 or more, further preferably 0.97 or more, 0.99 or more, 1.01 or more, 1.03 or more, 1.05 or more, 1.07 or more, 1.09 or more, 1.11 or more, 1.13 or more, 1.14 or more , 1.15 and above, 1.16 and above. In addition, from the viewpoint of maintaining the refractive index, maintaining low dispersion, and maintaining the thermal stability of the glass, the cation ratio (R ⁺ /(Al ³⁺ +P ⁵⁺ )) is preferably 2.00 or less, more preferably 1.98 or less. The order of 1.96 or less, 1.94 or less, 1.92 or less, 1.90 or less, 1.88 or less, 1.87 or less, 1.86 or less, and 1.85 or less is even better.

From the viewpoint of maintaining low dispersion, further lowering the Tg of the glass, improving the meltability of the glass, and reducing the specific gravity, the cation ratio of the total content of Li ⁺ and K ⁺ to the total content of Al ³⁺ and P ⁵⁺ ( (Li ⁺ +K ⁺ )/(Al ³⁺ +P ⁵⁺ )) is preferably 0.56 or more, more preferably 0.58 or more, 0.60 or more, 0.62 or more, 0.64 or more, 0.66 or more, 0.68 or more, 0.70 or more, 0.72 or more, The order of 0.74 or more, 0.76 or more, 0.78 or more, and 0.80 or more is more preferable. In addition, from the viewpoint of maintaining the refractive index, maintaining low dispersion, and maintaining thermal stability, the cation ratio ((Li ⁺ ＋K ⁺ )/(Al ³⁺ ＋P ⁵⁺ )) is preferably 1.40 or less, more preferably 1.38 or less. , the order of 1.36 or less, 1.34 or less, 1.32 or less, 1.30 or less, 1.28 or less, 1.27 or less, 1.26 or less, and 1.25 or less is even better.

From the viewpoint of further lowering the Tg of the glass and improving the meltability of the glass, the cation ratio of the total content of Li ⁺ and Na ⁺ to the total content of Li ⁺ and K ⁺ ((Li ⁺ +Na ⁺ )/(Li ⁺ +K ⁺ )) More preferably 0.50 or more, more preferably 0.55 or more, in the order of 0.60 or more, 0.65 or more, 0.70 or more, 0.75 or more, 0.80 or more, 0.85 or more, 0.86 or more, 0.87 or more, 0.88 or more, 0.89 or more, 0.90 or more Better still. From the viewpoint of further lowering the Tg of the glass and improving the meltability of the glass, the cation ratio ((Li ⁺ ＋Na ⁺ )/(Li ⁺ ＋K ⁺ )) is preferably 1.59 or less, more preferably 1.57 or less, and 1.55 or less, Below 1.53, below 1.51, below 1.49, below 1.47, below 1.45, below 1.43, below 1.41, below 1.39, below 1.37, below 1.35, below 1.33, below 1.31, below 1.29, below 1.28, below 1.27, below 1.26, below 1.25 , the order below 1.24 is even better.

Pb, As, Cd, Tl, Be and Se are each toxic, so it is better not to contain these elements, that is, not to introduce these elements into the glass as glass components. U, Th and Ra are all radioactive elements. Therefore, it is preferable not to contain these elements, that is, to not introduce these elements into the glass as glass components. V, Cr, Mn, Fe, Co, Ni, Cu, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm and Ce may increase the coloring of the glass or become a source of fluorescence. Therefore, it is preferable not to use it as an element contained in glass for optical elements. Therefore, it is preferable not to contain these elements, that is, to not introduce these elements into the glass as glass components.

Sb and Sn are optionally added elements that function as clarifiers. In terms of the mass fraction (%) of Sb ₂ O ₃ when the mass of the glass is 100, the Sb content of the optical glass may be, for example, 0.40% or less, 0.20% or less, 0.10% or less, 0.05% or less, or 0.02%. Below, below 0.01%. On the other hand, the Sb content may be 0.00% or more or 0.00% based on the mass fraction (%) of Sb ₂ O ₃ when the mass of glass is 100. In terms of the mass fraction (%) of _SnO2 when the mass of the glass is 100, the Sn content of the optical glass may be, for example, 0.40% or less, 0.20% or less, 0.10% or less, 0.05% or less, 0.02% or less, Below 0.01%. On the other hand, the Sn content may be 0.00% or more or 0.00% based on the mass fraction (%) of SnO ₂ when the mass of glass is 100.

The cationic component has been described above. Next, the anionic component will be described.

The above-mentioned optical glass contains at least O ^2- and ^F- as anionic components.

From the viewpoint of increasing the refractive index of glass and improving thermal stability, the O ^2- content is 10.0% or more, preferably 15.0% or more, 17.5% or more, 20.0% or more, 22.5% or more, 25.0% or more, 27.5% or more. % or more, 30.0% or more, 32.5% or more, 35.0% or more, 37.5% or more, 40.0% or more, 42.5% or more, 45.0% or more, 48.0% or more, 49.0% or more, 50.0% or more, 51.0% or more, 52.0% or more The order of , 53.0% and above, 54.0% and above, 55.0% and above, 56.0% and above, 57.0% and above, 58.0% and above and 59.0% and above is better. In addition, from the viewpoint of maintaining low dispersion and suppressing an increase in Tg of the glass, the O ^2- content is 95.0% or less, preferably 88.5% or less, 86.0% or less, 83.5% or less, 82.0% or less, 81.0% or less, The order of 80.0% or less, 79.0% or less, 78.0% or less, and 77.0% or less is better.

From the viewpoint of maintaining low dispersion and low Tg of the glass, the F ^- content is 10.0% or more, preferably 11.00% or more, 12.00% or more, 13.00% or more, 14.00% or more, 15.00% or more, 16.00% or more. , more than 17.00%, more than 18.00%, more than 19.00%, more than 20.00%, more than 21.00%, more than 22.00%, more than 23.00% in the order of better. In addition, from the viewpoint of improving the thermal stability of the glass and suppressing volatilization of the glass during melting, the F ^- content is 90.0% or less, preferably 85.0% or less, preferably 80.0% or less, 75.0% or less, 70.0% or less, 65.0% Below, below 63.0%, below 60.0%, below 57.0%, below 55.0%, below 54.0%, below 52.0%, below 50.0%, below 49.0%, below 48.0%, below 47.0%, below 46.0%, below 45.0%, The order of 44.0% or less and 43.0% or less is better.

Examples of anionic components other than O ^2- and F ^- include Cl ^- , Br ^- and I ^- . The Cl ^- content may be, for example, 0.0%, 0.0% or more, more than 0.0%, 0.10% or more, or 0.20% or more. In addition, for example, it may be 5.0% or less, 4.0% or less, 3.0% or less, 2.0% or less, 1.0% or less, Below 0.50%. The Br ^- content may be, for example, 0.0%, 0.0% or more, more than 0.0%, 0.10% or more, or 0.20% or more. In addition, for example, it may be 5.0% or less, 4.0% or less, 3.0% or less, 2.0% or less, 1.0% or less, Below 0.5%. The I ^- content may be, for example, 0.0%, 0.0% or more, more than 0.0%, 0.10% or more, or 0.20% or more. In addition, for example, it may be 5.0% or less, 4.0% or less, 3.0% or less, 2.0% or less, 1.0% or less, Below 0.5%.

＜Glass physical properties＞ (Abbe number νd) By having the above-mentioned glass composition, the optical glass can exhibit low dispersion. The Abbe number νd, which is an index of dispersion, is expressed as νd=(nd-1)/(nF-nC) using the refractive indices nd, nF, and nC for d-rays, F-rays, and C-rays. From the viewpoint of usefulness as a material for optical elements, the Abbe number νd of the optical glass is preferably 70.00 or more, more preferably 70.50 or more, in the order of 71.00 or more, 71.50 or more, 72.00 or more, 72.50 or more, and 73.00 or more. Better still. In addition, the Abbe's number νd of the optical glass may be, for example, 82.00 or less.

(refractive index nd) From the viewpoint of usefulness as a material for optical elements, the refractive index nd of the optical glass may be, for example, 1.420 or more, 1.425 or more, 1.430 or more, 1.435 or more, 1.440 or more, 1.445 or more, 1.446 or more, 1.447 or more, 1.448 or more, 1.449 or more, 1.450 or more, and, for example, 1.510 or less, 1.505 or less, 1.500 or less, 1.4950 or less, 1.490 or less, 1.489 or less, 1.488 or less, 1.487 or less, 1.486 or less, 1.485 or less, 1.484 or less, 1.483 or less, or 1.482 or less. In the present invention and this specification, "refractive index" refers to "refractive index nd", and refractive index nd refers to the refractive index at a wavelength of 587.56 nm.

(Glass transition temperature Tg) By having the above-mentioned glass composition, the optical glass can have a low glass transition temperature. The glass transition temperature Tg of the above-mentioned optical glass is preferably 350°C or lower, more preferably 340°C or lower, 330°C or lower, 320°C or lower, 310°C or lower, 300°C or lower, 290°C or lower, 280°C or lower, 270°C or lower , the order below 260℃ is even better. In addition, the glass transition temperature Tg of the optical glass may be, for example, 150°C or higher, 160°C or higher, 170°C or higher, 180°C or higher, 190°C or higher, or 200°C or higher. The glass transition temperature Tg is determined by the method described below.

(proportion) From the viewpoint of reducing the weight of the optical element, the optical glass preferably has a low specific gravity. The specific gravity of the optical glass may be, for example, 3.10 or less, 3.05 or less, 3.00 or less, 2.95 or less, 2.90 or less, or 2.85 or less. In addition, the specific gravity of the optical glass may be, for example, 2.55 or more. The lower the specific gravity, the better. Therefore, the lower limit is not particularly limited.

(Transmittance characteristics) The external transmittance of the above-mentioned optical glass at a wavelength of 500 nm to 1000 nm is more than 80% when converted to a thickness of 10.0 mm. "The external transmittance at a wavelength of 500nm~1000nm when converted to a thickness of 10.0mm is more than 80%" means that the external transmittance when converted to a thickness of 10.0mm is more than 80% in the entire wavelength range of 500nm~1000nm. The external transmittance of the above-mentioned optical glass at a wavelength of 500 nm to 1000 nm can be 80% or more and 100% or less when converted into a thickness of 10.0 mm. Optical glass having this transmittance characteristic is useful as a material for optical elements. For example, by making glass that does not contain Cu ²⁺ as a cationic component, the above-mentioned transmittance characteristics can be achieved.

The transmittance characteristics of the above-mentioned glass are determined by the following method. The glass sample is processed into parallel and optically polished planes, and the external transmittance at a wavelength of 500 to 1000 nm is measured. The external transmittance also includes the reflection loss of light from the sample surface. In addition, when the glass of the measurement object is not glass with the converted thickness, the thickness of the glass is d, the transmittance at each wavelength λ is converted by the following equation A, and the transmission can be obtained by conversion rate characteristics.

Formula A: T(λ)＝(1-R(λ)) ² ×exp(log _e ((T ₀ (λ)/100)/(1-R(λ)) ² )×d/d ₀ )× 100

In formula A, T (λ): converted transmittance (%) at wavelength λ, T ₀ (λ): measured transmittance (%) at wavelength λ, d: converted thickness (mm), d ₀ : Thickness of glass (mm), R(λ)=((n(λ)-1)/(n(λ)+1)) ² represents the reflectivity at wavelength λ, n(λ): refractive index at wavelength λ . For the refractive index n(λ) at wavelength λ, the refraction at each wavelength was measured in accordance with the Japanese Industrial Standard (JIS standard) JIS B 7071-1 "Refractive index measurement method of optical glass - Part 1: Minimum deflection angle method" Rate.

＜How to manufacture optical glass＞ The above-mentioned optical glass can be obtained as follows: weighing and blending phosphates, fluorides, oxides, carbonates, sulfates, nitrates, hydroxides, etc. as raw materials to obtain the target glass composition, and thoroughly mixing The mixed masterbatch is prepared, heated, melted, degassed, and stirred in a melting container to produce uniform, bubble-free molten glass, which is then molded to obtain optical glass. Specifically, it can be produced using a known melting method.

[Glass raw materials for press molding, optical element blanks, and their manufacturing methods] Another embodiment of the invention relates to: Glass raw materials for press molding containing the above-mentioned optical glass; and An optical element blank containing the above-mentioned optical glass.

According to another embodiment of the present invention, there is also provided: A method of manufacturing a glass raw material for press molding including a procedure for molding the optical glass described above into a glass raw material for press molding; A method for manufacturing an optical element blank including a procedure for press-molding the above-mentioned glass raw material for press-molding optical glass using a press-molding mold to produce an optical element blank; and A method for manufacturing an optical element blank including a procedure for molding the optical glass described above into an optical element blank.

The optical element blank is a material that is similar to the shape of the target optical element, and has a polishing material (a surface layer that will be removed by polishing) added to the shape of the optical element, and a grinding material (a surface layer that will be removed by polishing) if necessary. Surface layer removed by grinding) optical element base material. The optical element is finished by grinding and polishing the surface of the optical element blank. In one embodiment, the optical element blank can be produced by press-molding a molten glass obtained by melting an appropriate amount of the above-mentioned glass (called a direct press method). In another embodiment, an optical element blank can also be produced by solidifying a molten glass obtained by melting an appropriate amount of the above-mentioned glass.

In another embodiment, an optical element blank can be produced by producing a glass material for press molding and press-molding the produced glass material for press molding.

Pressure molding of the glass raw material for press molding can be performed by a known method of pressurizing the heated and softened glass raw material for press molding using a press molding die. Both heating and pressure molding can be performed in the atmosphere. By annealing after pressure molding to reduce the strain inside the glass, a uniform optical element blank can be obtained.

As for the glass raw material for press molding, in addition to the raw material called glass gob for press molding that is directly supplied to the press molding for producing the optical element blank in its original state, there are also Including raw materials that are supplied to pressure molding after mechanical processing such as cutting, grinding, and polishing, and passing through glass gobs for pressure molding. The cutting method includes the following method: forming a groove on the part to be cut on the surface of the glass plate by a method called scribing, applying local pressure to the groove part from the back side of the side on which the groove is formed, and placing the groove on the surface of the glass plate. The method of partially cutting the glass plate; the method of cutting the glass plate with a cutting knife, etc. In addition, examples of grinding and polishing methods include barrel polishing and the like.

The glass raw material for pressure molding can be produced by, for example, casting molten glass into a mold and shaping it into a glass plate, and cutting the glass plate into a plurality of glass sheets. Alternatively, an appropriate amount of molten glass may be molded to produce glass gobs for pressure molding. The optical element blank can also be produced by reheating and softening the glass gob for pressure molding and performing pressure molding. The method of reheating, softening, and press-molding glass to produce an optical element blank is called a reheat press method compared to the direct press method.

[Optical elements and manufacturing methods thereof] Another embodiment of the invention relates to: Optical elements containing the above-mentioned optical glass. The above-mentioned optical element is produced using the above-mentioned optical glass. In the optical element described above, one or more coating layers, such as a multilayer film such as an antireflection film, may be formed on the glass surface.

In addition, according to an embodiment of the present invention, it can also be provided: An optical element manufacturing method including a procedure for producing an optical element by grinding and/or polishing the above-mentioned optical element blank.

In the above-mentioned manufacturing method of optical elements, mechanical processing such as grinding and polishing can be performed by known methods. By fully cleaning and drying the surface of the optical element after processing, optical elements with high internal and surface quality can be obtained. . In this way, an optical element formed of the above-mentioned optical glass can be obtained. Examples of optical elements include various lenses such as spherical lenses, aspherical lenses, and microlenses, lenses, and the like.

In addition, the optical element formed of the above-mentioned optical glass is also suitably used as a lens constituting a joint optical element. Examples of the bonded optical element include an element in which lenses are bonded to each other (cemented lens), an element in which a lens and a lens are bonded together, and the like. For example, a bonded optical element can be produced by precisely processing (for example, spherical surface polishing) the bonding surface of two optical elements so that their shapes become inverted shapes, and applying a coating for bonding the lens. The ultraviolet curing adhesive is used to bond them. After they are bonded, ultraviolet rays are irradiated through the lens to solidify the adhesive, thereby making the joint optical components. Multiple elements to be joined can be made using various types of glass with different Abbe numbers νd and then joined together to produce an element suitable for compensating chromatic aberration. [Example]

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the embodiments shown in the examples.

[Example 1] ＜Sample No.1~88＞ In order to achieve the glass composition shown in the table below, the corresponding phosphate, fluoride, nitrate, sulfate, carbonate, hydroxide, oxide, boric acid, etc. are used as raw materials for introducing each component. Measure the raw materials and mix them thoroughly to prepare the prepared raw materials. This prepared raw material was put into a platinum crucible, heated in a furnace set to 700 to 1100°C, and melted for 90 minutes. After the molten glass is stirred and homogenized, the molten glass is poured into a preheated mold. After natural cooling to near the glass transition temperature, it is immediately placed in an annealing furnace and maintained at a temperature around the glass transition temperature for about 30 minutes. By slowly cooling at a slow cooling rate of -30° C./hour for 4 hours, and then naturally cooling to room temperature in the furnace, optical glasses of sample Nos. 1 to 88 shown in the following tables were obtained.

[Comparative Example A, Comparative Example B] In order to achieve the glass composition shown in the table below, the corresponding phosphate, fluoride, nitrate, sulfate, carbonate, hydroxide, oxide, boric acid, etc. are used as raw materials for introducing each component. Measure the raw materials and mix them thoroughly to prepare the prepared raw materials. This prepared raw material was put into a platinum crucible, heated in a furnace set to 700 to 1100°C, and melted for 90 minutes. After the molten glass is stirred and homogenized, the molten glass is poured into a preheated mold. After natural cooling to near the glass transition temperature, it is immediately placed in an annealing furnace and maintained at a temperature around the glass transition temperature for about 30 minutes. The optical glass of Comparative Example A and Comparative Example B shown in the following table was obtained by slowly cooling for 4 hours at a slow cooling rate of -30° C./hour, and then naturally cooling to room temperature in the furnace. Comparative Example A corresponds to Example 33 of WO2003/037813 (Patent Document 1), and Comparative Example B corresponds to Example 35 of WO2003/037813 (Patent Document 1).

＜Physical property evaluation＞ Each physical property of each optical glass shown in the following table was measured by the method shown below.

(1) Refractive index nd, Abbe’s number νd For each optical glass, the refractive index nd and Abbe's number νd were measured by the refractive index measurement method standardized by the Japan Optical Glass Industry Association. Regarding Comparative Example A, since the glass was devitrified, the refractive index nd and Abbe's number νd could not be measured.

(2) Glass transition temperature Tg The glass was thoroughly crushed with a mortar and used as a sample. A platinum cell was used as a sample container. The temperature rise rate was set to 10°C/min using a differential scanning calorimetry analysis device (DSC3300SA) manufactured by NETZSCH JAPAN. The glass transition temperature Tg was measured.

(3) Proportion The specific gravity was determined by Archimedes' method.

(4) Transmittance characteristics A test piece was cut out from the obtained glass, and both sides were mirror-polished to form optically polished planes parallel to each other. After the thickness reached 10.0 mm, a spectrophotometer was used to measure the external transmittance at a wavelength of 500 to 1000 nm. Determination was carried out. In any of Sample Nos. 1 to 88, Comparative Examples A and Comparative Examples B, it was confirmed that the external transmittance at a wavelength of 500 nm to 1000 nm was 80% or more and 100% or less when the thickness was 10.0 mm.

<Evaluation of thermal stability> For sample Nos. 1 to 88, Comparative Example A and Comparative Example B, corresponding phosphates, fluorides, nitrates, and Sulfates, carbonates, hydroxides, oxides, boric acid, etc. are used as raw materials for introducing each component. The raw materials are weighed and thoroughly mixed to prepare the prepared raw materials. This prepared raw material was put into a platinum crucible, heated in a furnace set to 700 to 1100°C, and melted for 90 minutes. After the molten glass was stirred and homogenized, the molten glass was cast into a mold, molded, and slowly cooled to obtain a massive glass sample. The obtained glass sample was observed with an optical microscope for crystals in the glass. Set the magnification of the optical microscope to 40 to 100 times. When no crystals are confirmed in the glass block, it is judged as A. When more than 1 and 15 or less crystals are confirmed per 1 cm ³ on average, it is judged as B. When 16 or more and 40 crystals are confirmed on average per 1 cm ³ , it is judged as B. When there are less than 40 crystals per 1 cm 3 , it is judged as C, and when more than 40 crystals are confirmed per 1 cm ³ , it is judged as D. Regarding A, B, and C, the thermal stability increases in the order of C→B→A, and A has the highest thermal stability. If it is A, B, or C, the internal quality, which is the number of crystals contained in the glass during production, is within the allowable range. Glass with a judgment result of D lacks thermal stability and is of poor internal quality in terms of manufacturing. As shown in the following table, it was confirmed that the glass of sample Nos. 1 to 88 has excellent thermal stability (judgment result A, B, or C).

(Example 2) A glass block (glass gob) for press molding was produced using various glasses obtained in Example 1. The glass gob was heated and softened in the air, and then press-molded using a pressure molding die to produce a lens blank (optical element blank). The produced lens blank was taken out from the pressure molding mold, annealed, and machined including polishing to produce spherical lenses made of various glasses produced in Example 1.

(Example 3) A desired amount of the molten glass produced in Example 1 was press-molded using a press-molding die to produce a lens blank (optical element blank). The produced lens blank was taken out from the pressure molding mold, annealed, and mechanically processed including polishing to produce spherical lenses made of various glasses produced in Example 1.

(Example 4) The glass block (optical element blank) produced by solidifying the molten glass produced in Example 1 was annealed and machined including polishing to produce spherical lenses made of various glasses produced in Example 1.

Finally, each of the above-described embodiments is summarized.

[1] An optical glass in which the S ⁶⁺ content exceeds 0.0 cation % and is 30.0 cation % or less, and the Al ³⁺ content exceeds 0.0 cation % and is 30.0 cation % or less in the glass composition expressed as cation %, P ^{5 The +} content is 5.0 cation % or more and 50.0 cation % or less, the Li ⁺ content is 0.0 cation % or more and 51.0 cation % or less, the Na ⁺ content is 0.0 cation % or more and 44.0 cation % or less, the K ⁺ content is 0.0 cation % or more and 44.0 cation % or less. 45.0 cation % or less, the total content of Li ⁺ , Na ⁺ , K ⁺ and Cs ⁺ R ⁺ is 5.0 cation % or more, the total content of Be ²⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ and Ba ²⁺ Assuming that R ²⁺ is used, the cation ratio of R ²⁺ to the total content of Al ³⁺ and R ²⁺ (R ²⁺ /(Al ³⁺ +R ²⁺ )) is 0.56 or less, and the glass composition expressed as anion % In, the O ^2- content is 10.0 anion% or more and 95.0 anion% or less, the F ^- content is 10.0 anion% or more and 90.0 anion% or less, and the external transmittance of the optical glass at a wavelength of 500nm~1000nm is converted into a thickness of 10.0mm is more than 80%. [2] The optical glass according to [1], wherein the cation ratio of the P ⁵⁺ content to the total content of Al ³⁺ and P ⁵⁺ (P ⁵⁺ /(Al ³⁺ +P ⁵⁺ )) is 0.30 Above and below 0.85. [3] The optical glass according to [1] or [2], wherein the cation ratio (Li ⁺ /(R ⁺ +R ²⁺ )) of the Li ⁺ content to the total of R ⁺ and R ²⁺ is 0.00 or more And below 1.00. [4] The optical glass according to any one of [1] to [3], wherein the cation ratio of R ⁺ to the total content of Al ³⁺ and P ⁵⁺ (R ⁺ /(Al ³⁺ +P ^{5 +} )) is above 0.93. [5] The optical glass according to any one of [1] to [4], wherein the cation ratio of the total content of Li ⁺ and K ⁺ to the total content of Al ³⁺ and P ⁵⁺ ((Li ⁺ +K ⁺ )/(Al ³⁺ +P ⁵⁺ )) is 0.56 or more. [6] The optical glass according to any one of [1] to [5], wherein the cation ratio of the total content of Li ⁺ and Na ⁺ to the total content of Li ⁺ and K ⁺ ((Li ⁺ +Na ⁺ )/(Li ⁺ ＋K ⁺ )) is 0.50 or more and 1.59 or less. [7] The optical glass according to any one of [1] to [6], whose glass transition temperature Tg is 150°C or more and 350°C or less. [8] The optical glass according to any one of [1] to [7], whose Abbe number νd is 70.00 or more and 82.00 or less. [9] The optical glass according to [1], wherein the cation ratio of the P ⁵⁺ content to the total content of Al ³⁺ and P ⁵⁺ (P ⁵⁺ /(Al ³⁺ +P ⁵⁺ )) is 0.30 or more and 0.85 or less, the Li ⁺ content relative to the total cation ratio of R ⁺ and R ²⁺ (Li ⁺ /(R ⁺ ＋R ²⁺ )) is 0.00 or more and 1.00 or less, R ⁺ relative to Al ³⁺ and P ⁵ The cation ratio of the total content of ⁺ (R ⁺ /(Al ³⁺ +P ⁵⁺ )) is 0.93 or more, and the cation ratio of the total content of Li ⁺ and K ⁺ to the total content of Al ³⁺ and P ⁵⁺ ((Li ⁺ ＋K ⁺ )/(Al ³⁺ ＋P ⁵⁺ )) is 0.56 or more, and the cation ratio of the total content of Li ⁺ and Na ⁺ to the total content of Li ⁺ and K ⁺ ((Li ⁺ ＋Na ⁺ )/(Li ⁺ +K ⁺ )) is 0.50 to 1.59, the glass transition temperature Tg of the optical glass is 150°C to 350°C, and the Abbe number νd is 70.00 to 82.00. [10] An optical element including the optical glass described in any one of [1] to [9].

It should be understood that the embodiments disclosed this time are all exemplary and not limiting. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims. For example, by adjusting the composition described in the specification with respect to the glass composition exemplified above, optical glass according to one embodiment of the present invention can be obtained. It goes without saying that two or more of the matters exemplified in the specification or described as preferred ranges can be arbitrarily combined.

without

without

Claims (10)

An optical glass in which the S ⁶⁺ content exceeds 0.0 cation % and is less than 30.0 cation %, the Al ³⁺ content exceeds 0.0 cation % and is less than 30.0 cation %, and the P ⁵⁺ content is 5.0 cation % or more and 50.0 cation % or less, Li ⁺ content is 0.0 cation % or more and 51.0 cation % or less, Na ⁺ content is 0.0 cation % or more and 44.0 cation % or less, K ⁺ content is 0.0 cation % or more and 45.0 cation % Hereinafter, the total content R ⁺ of Li ⁺ , Na ⁺ , K ⁺ and Cs ⁺ is 5.0 cation % or more, and the total content of Be ²⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ and Ba ²⁺ is defined as R ²⁺ , the cation ratio of R ²⁺ to the total content of Al ³⁺ and R ²⁺ (R ²⁺ /(Al ³⁺ +R ²⁺ )) is 0.56 or less, and in the glass composition expressed as anion %, O The ^2- content is 10.0 anion% or more and 95.0 anion% or less, the F ^- content is 10.0 anion% or more and 90.0 anion% or less, and the external transmittance of the optical glass at a wavelength of 500nm~1000nm is converted into a thickness of 10.0mm. More than 80%. The optical glass according to claim 1, wherein the cation ratio of the P ⁵⁺ content to the total content of Al ³⁺ and P ⁵⁺ (P ⁵⁺ /(Al ³⁺ +P ⁵⁺ )) is 0.30 or more and 0.85 the following. The optical glass according to claim 1, wherein the cation ratio (Li ⁺ /(R ⁺ +R ²⁺ )) of the Li ⁺ content to the total of R ⁺ and R ²⁺ is 0.00 or more and 1.00 or less. The optical glass according to claim 1, wherein the cation ratio of R ⁺ to the total content of Al ³⁺ and P ⁵⁺ (R ⁺ /(Al ³⁺ +P ⁵⁺ )) is 0.93 or more. The optical glass according to claim 1, wherein the cation ratio of the total content of Li ⁺ and K ⁺ to the total content of Al ³⁺ and P ⁵⁺ is ((Li ⁺ +K ⁺ )/(Al ³⁺ +P ⁵⁺ )) is above 0.56. The optical glass according to claim 1, wherein the cation ratio ((Li ^{+ ＋} Na ⁺ )/(Li ⁺ ＋K ⁺ )) of the total content of Li ⁺ and Na ⁺ to the total content of Li + and K ⁺ is 0.50 Above and below 1.59. The optical glass according to claim 1, wherein the glass transition temperature Tg of the optical glass is 150°C or more and 350°C or less. The optical glass according to claim 1, wherein the Abbe number νd of the optical glass is 70.00 or more and 82.00 or less. The optical glass according to claim 1, wherein the cation ratio of the P ⁵⁺ content to the total content of Al ³⁺ and P ⁵⁺ (P ⁵⁺ /(Al ³⁺ +P ⁵⁺ )) is 0.30 or more and 0.85 Hereinafter, the cation ratio (Li ⁺ /(R ⁺ ＋R ²⁺ )) of the Li ⁺ content relative to the total of R ⁺ and R ²⁺ is 0.00 or more and 1.00 or less, and the R ⁺ content relative to the total of Al ³⁺ and P ⁵⁺ The cation ratio of the content (R ⁺ /(Al ³⁺ +P ⁵⁺ )) is 0.93 or more, and the cation ratio of the total content of Li ⁺ and K ⁺ to the total content of Al ³⁺ and P ⁵⁺ ((Li ⁺ +K ⁺ )/(Al ³⁺ ＋P ⁵⁺ )) is 0.56 or more, and the cation ratio of the total content of Li ⁺ and Na ⁺ to the total content of Li ⁺ and K ⁺ ((Li ⁺ ＋Na ⁺ )/(Li ⁺ ＋K ⁺ ) ) is 0.50 or more and 1.59 or less, the glass transition temperature Tg of the optical glass is 150°C or more and 350°C or less, and the Abbe number νd is 70.00 or more and 82.00 or less. An optical element comprising the optical glass as described in any one of claims 1 to 9.