CN117209145A - Optical glass and optical element - Google Patents

Abstract

The invention provides an optical glass having low glass transition temperature, low dispersion and excellent thermal stability. The optical glass of the present invention has the following glass composition expressed in cation%: s is S ⁶⁺ The content exceeds 0.0% and is less than 30.0%, al ³⁺ The content exceeds 0.0%And is 30.0% or less, P ⁵⁺ The content of Li is 5.0% or more and 50.0% or less ⁺ The content is more than 0.0% and less than 51.0%, na ⁺ The content is more than 0.0% and less than 44.0%, K ⁺ The content of Li is 0.0% or more and 45.0% or less ⁺ 、Na ⁺ 、K ⁺ Cs ⁺ Is the total content R of ⁺ Above 5.0%, be ²⁺ 、Mg ²⁺ 、Ca ²⁺ 、Sr ²⁺ Ba and Ba ²⁺ The total content of (2) is R ²⁺ ，R ²⁺ Relative to Al ³⁺ And R is R ²⁺ Cation ratio (R) ²⁺ /(Al ³⁺ +R ²⁺ ) 0.56 or less, having the following glass composition in terms of anion%: o (O) ^2‑ The content of F is 10.0% to 95.0% ^‑ The content is 10.0% or more and 90.0% or less, and the external transmittance of the optical glass at a wavelength of 500nm to 1000nm is 80% or more in terms of thickness of 10.0 mm.

Description

Optical glass and optical element

Technical Field

The present invention relates to an optical glass and an optical element.

Background

For example, patent document 1 discloses an optical glass having a low glass transition temperature.

Prior art literature

Patent literature

Patent document 1: WO2003/037813

Disclosure of Invention

Problems to be solved by the invention

The glass having a low glass transition temperature can be molded at a low temperature, and it is preferable that the glass be molded at a low temperature from the viewpoints of less deterioration of a molding die due to heating, low heat resistance and low cost, and the like.

In projection optical systems such as image pickup optical systems and projectors, chromatic aberration can be compensated and miniaturization of the optical system can be achieved by combining lenses having different chromatic dispersion to form a cemented lens. Since low dispersion is generally easily achieved by a plastic lens, an optical glass having low dispersion is useful as a material for an optical element constituting a projection optical system such as an image pickup optical system and a projector.

In view of the above, the present inventors have studied an optical glass having a low glass transition temperature and low dispersion, and as a result have found that further improvement in thermal stability can be expected.

An object of one embodiment of the present invention is to provide an optical glass having a low glass transition temperature, low dispersion, and excellent thermal stability.

Means for solving the problems

One embodiment of the present invention relates to an optical glass, which has a glass composition expressed in cation%,

S ⁶⁺ the content exceeds 0.0 cation% and is 30.0 cation% or less,

Al ³⁺ the content exceeds 0.0 cation% and is 30.0 cation% or less,

P ⁵⁺ the content is 5.0 to 50.0 cation%,

Li ⁺ the content is 0.0 cation% or more and 51.0 cation% or less,

Na ⁺ the content is more than 0.0 cation% and less than 44.0 cation%,

K ⁺ the content is 0.0 to 45.0 cation%,

Li ⁺ 、Na ⁺ 、K ⁺ cs ⁺ Is the total content R of ⁺ Is more than 5.0 percent of cation,

be is carried out ²⁺ 、Mg ²⁺ 、Ca ²⁺ 、Sr ²⁺ Ba and Ba ²⁺ The total content of (2) is R ²⁺ ，R ²⁺ Relative to Al ³⁺ And R is R ²⁺ Cation ratio (R) ²⁺ /(Al ³⁺ +R ²⁺ ) Is not more than 0.56 and is not more than,

in the glass composition expressed in anion%,

O ^2- the content is 10.0-95.0 anion%,

F ^- the content is 10.0-90.0 anion%,

the optical glass has an external transmittance of 80% or more in terms of a thickness of 10.0mm at a wavelength of 500nm to 1000 nm.

The optical glass has the glass composition, thereby having a low glass transition temperature and low dispersion, and exhibiting excellent thermal stability.

ADVANTAGEOUS EFFECTS OF INVENTION

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

Detailed Description

[ optical glass ]

In the present invention and the present specification, unless otherwise specified, the content and total content of the cationic components are represented by cation%, and unless otherwise specified, the content and total content of the anionic components are represented by anion%.

Here, "cation%" is a value calculated as "(number of cations of interest/total number of cations of glass component) ×100", and represents a mole percentage of the amount of cations of interest with respect to the total amount of cation components.

The "anion%" is a value calculated as "(number of anions of interest/total number of anions of the glass component) ×100", and represents a mole percentage of the amount of anions of interest with respect to the total amount of the anion component.

The molar ratio of the content between the cationic components is equal to the ratio of the content in cationic% of the cationic component concerned.

The content of each component can be quantified by a known method, for example, inductively coupled plasma emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), ion chromatography, or the like.

Regarding cationic components, for example, like Al ³⁺ 、P ⁵⁺ This indicates the valence of the cationic component (e.g., al ³⁺ The valence number of (C) is +3, P ⁵⁺ Valence of +5) is a value determined according to the convention, and Al, P, etc. are expressed as Al based on oxide ₂ O ₃ 、P ₂ O ₅ And the like. With respect to the oxide basis expressed as A _m O _n (A represents a cation, O represents oxygen, m and n are stoichiometrically determined integers), and A represents A ^s+ Wherein s=2n/m. Therefore, for example, the valence of the cationic component may not be analyzed when analyzing and quantifying the glass composition. The above points are also the same for the anionic component, in the case of the glassThe valence of the anionic component may not be analyzed when analyzing and quantifying the composition of the glass.

In the present invention and the present specification, the content of the constituent component being 0.0%, 0.00%, free of, or not including the constituent component means that the constituent component is substantially not included, and the content of the constituent component is not more than the impurity level, and not more than the impurity level means, for example, less than 0.01%.

In the present invention and in the present specification, "thermal stability" means the degree to which crystals are less likely to precipitate when glass in a molten state solidifies.

Hereinafter, the glass transition temperature may be referred to as Tg.

Hereinafter, the optical glass (may be simply referred to as "glass") will be described in more detail.

< glass composition >)

Hereinafter, a glass composition expressed as cation% of the optical glass will be described.

S from the viewpoints of lowering Tg of glass, maintaining refractive index and low dispersion, and improving thermal stability ⁶⁺ The content is more than 0%, preferably 0.5% or more, more preferably in the order of 1.0% or more, 1.2% or more, 1.3% or more, 1.4% or more, 1.5% or more, 1.6% or more, 1.7% or more, 1.8% or more, 1.9% or more, 2.0% or more, 2.1% or more, 2.2% or more, 2.3% or more, 2.4% or more, 2.5% or more, 2.6% or more, 2.7% or more, 2.8% or more, 2.9% or more, 3.0% or more.

In addition, from the viewpoints of maintaining refractive index, maintaining thermal stability and suppressing the rise of liquid phase temperature, S ⁶⁺ The content is 30.0% or less, preferably 29.0% or less, more preferably 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, and 14.0% or less.

From the viewpoints of improving refractive index and maintaining low dispersion, and improving thermal stability and maintaining chemical durability of glass, al ³⁺ The content exceeds 0.0%, preferably 1.0% or more, more preferably in the order of 2.0% or more, 3.0% or more, 4.0% or more, 5.0% or more, 6.0% or more, 7.0% or more, 8.0% or more, 9.0% or more, 10.0% or more, 11.0% or more.

In addition, from the viewpoint of suppressing the rise in Tg, al ³⁺ The content is 30.0% or less, preferably 29.0% or less, more preferably 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, and 18.0% or less.

From the viewpoint of maintaining low dispersion and improving thermal stability of glass, P ⁵⁺ The content is 5.0% or more, preferably 7.0% or more, more preferably 9.0% or more, 11.0% or more, 13.0% or more, 14.0% or more, 15.0% or more, 16.0% or more, 17.0% or more in this order.

In addition, from the viewpoints of maintaining the refractive index, improving the thermal stability of the glass, and suppressing the decrease in chemical durability, P ⁵⁺ The content is 50.0% or less, preferably 48.0% or less, more preferably 46.0% or less, 44.0% or less, 42.0% or less, 40.0% or less, 38.0% or less, 37.0% or less, 36.0% or less, 35.0% or less, 34.0% or less, 33.0% or less, and 32.0% or less.

Li from the viewpoints of improving refractive index and maintaining low dispersion, and lowering Tg of glass, improving meltability and lowering specific gravity of glass ⁺ The content is 0.0% or more, preferably 1.0% or more, more preferably in the order of 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.

In addition, from the viewpoint of improving the thermal stability of the glass and suppressing the decrease in chemical durability, li ⁺ The content is less than 51.0%, preferably less than 48.0%, and less than 45.0%, less than 43.0%, less than 41.0%, less than 40.0%, less than 39.0%, less than 38.0%, less than 37.0%, and less than 36.0%The order of 35.0% or less, 34.0% or less, 33.0% or less, 32.0% or less, and 31.0% or less is more preferable.

From the viewpoints of maintaining refractive index, maintaining low dispersion, lowering Tg of glass, improving meltability of glass, and lowering specific gravity, na ⁺ The content is 0.0% or more, preferably 1.0% or more, more preferably in the order of 2.0% or more, 3.0% or more, 4.0% or more, 5.0% or more, 6.0% or more, 7.0% or more, 8.0% or more, 9.0% or more.

In addition, from the viewpoint of improving the thermal stability of the glass and suppressing the decrease in chemical durability, na ⁺ The content is 44.0% or less, preferably 42.0% or less, more preferably 40.0% or less, 38.0% or less, 36.0% or less, 34.0% or less, 32.0% or less, 30.0% or less, 28.0% or less, 26.0% or less, 24.0% or less, 22.0% or less, 20.0% or less, and 19.0% or less.

K is from the viewpoints of maintaining refractive index, maintaining low dispersion, lowering Tg of glass, improving meltability of glass and lowering specific gravity ⁺ The content is more preferably 0.0% or more, preferably 1.0% or more, and more preferably 2.0% or more, 3.0% or more, 4.0% or more, 5.0% or more, and 6.0% or more in this order.

In addition, from the viewpoints of improving the thermal stability of the glass, suppressing the decrease in chemical durability and reducing the specific gravity, K ⁺ The content is 45.0% or less, and more preferably 43.0% or less, 40.0% or less, 38.0% or less, 36.0% or less, 34.0% or less, 32.0% or less, 30.0% or less, 28.0% 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, and 15.0% or less.

Li from the viewpoints of maintaining low dispersion, lowering Tg of glass, lowering specific gravity and lowering liquid phase temperature ⁺ 、Na ⁺ 、K ⁺ Cs ⁺ Is the total content R of ⁺ More than 5.0%, preferably more than 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 preferably, the order of the above is 33.0% or more, 35.0% or more, 37.0% or more, 40.0% or more, and 42.0% or more.

In addition, from the viewpoints of maintaining low dispersion, maintaining thermal stability of glass, and suppressing decrease in chemical durability, li ⁺ 、Na ⁺ 、K ⁺ Cs ⁺ Is the total content R of ⁺ Preferably 65.0% or less, more preferably 64.0% or less, 63.0% or less, 62.0% or less, 61.0% or less, 60.0% or less, 59.0% or less.

Cs ⁺ The content may be 0.0%, or 0.0% or more, or may exceed 0.0%. From the viewpoint of lowering Tg of glass and improving meltability of glass, cs ⁺ The content may be 0.0% or more, preferably 0.1% or more, more preferably in the order of 0.2% or more, 0.3% or more, 0.4% or more, 0.5% or more, 0.6% or more.

In addition, cs is considered from the viewpoint of improving the thermal stability of the glass and suppressing the decrease in chemical durability ⁺ The content is preferably 10.0% or less, more preferably in the order of 8.0% or less, 6.0% or less, 4.0% or less, 2.0% or less, 1.5% or less, 1.0% or less.

From the viewpoint of suppressing the rise of Tg and maintaining the thermal stability of the glass, be ²⁺ 、Mg ²⁺ 、Ca ²⁺ 、Sr ²⁺ Ba and Ba ²⁺ The total content of (2) is R ²⁺ In the optical glass, R ²⁺ Relative to Al ³⁺ And R is R ²⁺ Cation ratio (R) ²⁺ /(Al ³⁺ +R ²⁺ ) 0.56 or less, preferably 0.55 or less, more preferably 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, and 0.37 or less.

In addition, cation ratio (R ²⁺ /(Al ³⁺ +R ²⁺ ) In the range of 0.00 or more than 0.00, preferably 0.01 or more, 0.02 or more, 0.0 from the viewpoints of lowering Tg of glass and improving meltability of glassThe order of 3 or more is more preferable.

Be ²⁺ The content may be 0.0%, 0.0% or more than 0.0%. Be from the viewpoints of maintaining refractive index, maintaining low dispersion, suppressing increase in Tg, and maintaining thermal stability of glass ²⁺ The content is preferably 15.0% or less, more preferably 10.0% or less, and further preferably 5.0% or less, 2.5% or less, 1.5% or less, 1.0% or less, and 0.5% or less in this order.

Mg ²⁺ The content may be 0.0%, 0.0% or more than 0.0%. From the viewpoints of maintaining refractive index, maintaining low dispersion, suppressing increase in Tg, and maintaining thermal stability of glass, mg ²⁺ The content is preferably 15.0% or less, more preferably 14.0% or less, and further preferably 13.0% or less, 12.0% or less, 11.0% or less, and 10.0% or less.

Ca ²⁺ The content may be 0.0%, 0.0% or more than 0.0%. From the viewpoints of maintaining refractive index, maintaining low dispersion, suppressing increase in Tg, and maintaining thermal stability of glass, ca ²⁺ The content is preferably 15.0% or less, more preferably 14.0% or less, and further preferably 13.0% or less, 12.0% or less, 11.0% or less, 10.0% or less, 9.0% or less, 8.0% or less, 7.0% or less, 6.0% or less, and 5.0% or less.

Sr ²⁺ The content may be 0.0%, 0.0% or more than 0.0%. Sr is contained in the glass from the viewpoints of maintaining the refractive index, maintaining low dispersion, suppressing the rise of Tg and maintaining the thermal stability of the glass ²⁺ The content is preferably 10.0% or less, more preferably 9.0% or less, and further preferably in the order of 8.0% or less, 7.0% or less, 6.0% or less, 5.0% or less, and 4.0% or less.

Ba ²⁺ The content may be 0.0%, 0.0% or more than 0.0%. From the viewpoints of maintaining refractive index, maintaining low dispersion, improving meltability of glass, suppressing rise of Tg, and maintaining thermal stability of glass, ba ²⁺ The 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% or lessFurther preferred is the order of (2).

Be ²⁺ 、Mg ²⁺ 、Ca ²⁺ 、Sr ²⁺ Ba and Ba ²⁺ Is the total content R of ²⁺ May be 0.0%, 0.0% or more than 0.0%. From the viewpoints of maintaining refractive index, maintaining low dispersion, suppressing Tg rise and maintaining glass thermal stability, the total content R ²⁺ It is preferably 20.0% or less, more preferably 19.0% or less, and further preferably 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% or less, 11.0% or less, and 10.0% or less.

Zn ²⁺ The content may be 0.0%, 0.0% or more than 0.0%. Zn (zinc) ²⁺ While the effect of maintaining the refractive index and improving the thermal stability is exerted, if the content is excessive, dispersion tends to be high. From the above point of view, zn ²⁺ The content is preferably 20.0% or less, more preferably 19.0% or less, and further preferably 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% or less, 11.0% or less, and 10.0% or less.

Zr ⁴⁺ The content may be 0.0%, 0.0% or more than 0.0%. Zr (Zr) ⁴⁺ The component increases the refractive index, but if it is contained excessively, dispersion tends to increase, and Tg tends to increase. From the above point of view, zr ⁴⁺ The content is preferably 10.0% or less, more preferably 9.0% or less, and further preferably in 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, 2.0% or less.

From the viewpoints of maintaining low dispersion, further improvement of thermal stability of glass, further lowering Tg of glass, and improvement of glass meltability, P ⁵⁺ Content relative to Al ³⁺ And P ⁵⁺ Cation ratio (P) ⁵⁺ /(Al ³⁺ +P ⁵⁺ ) More preferably 0.30 or more, still more preferably 0.35 or more, and further preferably in the order of 0.40 or more, 0.45 or more, and 0.50 or more.

In addition, from the maintained refractive index and the maintenanceFrom the viewpoint of chemical durability, the cation ratio (P ⁵⁺ /(Al ³⁺ +P ⁵⁺ ) Preferably 0.85 or less, more preferably 0.83 or less, and further preferably in the order of 0.81 or less, 0.80 or less, 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.

Li from the viewpoints of increasing the refractive index, further lowering the Tg of the glass, and improving the meltability of the glass ⁺ Content relative to R ⁺ And R is R ²⁺ Is a total cation ratio (Li ⁺ /(R ⁺ +R ²⁺ ) More preferably 0.00 or more, still more preferably 0.05 or more, and further preferably 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, and 0.40 or more in this order.

In addition, from the viewpoint of further lowering Tg of the glass and improving the meltability of the glass, the cation ratio (Li ⁺ /(R ⁺ +R ²⁺ ) Preferably 1.00 or less, more preferably 0.95 or less, and further preferably 0.92 or less, 0.90 or less, 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.

R is from the viewpoints of maintaining low dispersion, further lowering Tg of glass, improving meltability of glass and lowering specific gravity ⁺ Relative to Al ³⁺ And P ⁵⁺ Cation ratio (R) ⁺ /(Al ³⁺ +P ⁵⁺ ) More preferably 0.93 or more, still more preferably 0.95 or more, still more 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 or more, 1.16 or more.

In addition, from the viewpoints of maintaining refractive index, maintaining low dispersion, and maintaining thermal stability of glass, the cation ratio (R ⁺ /(Al ³⁺ +P ⁵⁺ ) Preferably 2.00 or less, more preferably 1.98 or less, 1.96 or less, 1.94 or less, 1.92 or less, 1.90 or less, 1.88 or lessThe order of 1.87 or less, 1.86 or less, and 1.85 or less is more preferable.

Li from the viewpoints of maintaining low dispersion, further lowering Tg of the glass, improving meltability of the glass and lowering specific gravity ⁺ And K is equal to ⁺ Relative to Al ³⁺ And P ⁵⁺ Cation ratio ((Li) ⁺ +K ⁺ )/(Al ³⁺ +P ⁵⁺ ) More preferably 0.56 or more, still more preferably 0.58 or more, and further preferably in the order of 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, 0.74 or more, 0.76 or more, 0.78 or more, 0.80 or more.

In addition, from the viewpoints of maintaining refractive index, maintaining low dispersion, and maintaining thermal stability, the cation ratio ((Li) ⁺ +K ⁺ )/(Al ³⁺ +P ⁵⁺ ) Preferably 1.40 or less, more preferably 1.38 or less, and further preferably 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.

From the viewpoint of further lowering Tg of the glass and improving the meltability of the glass, li ⁺ With Na and Na ⁺ Relative to Li ⁺ And K is equal to ⁺ Cation ratio ((Li) ⁺ +Na ⁺ )/(Li ⁺ +K ⁺ ) More preferably 0.50 or more, still more preferably 0.55 or more, and further preferably 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.

From the viewpoint of further lowering Tg of the glass and improving the meltability of the glass, the cation ratio ((Li) ⁺ +Na ⁺ )/(Li ⁺ +K ⁺ ) Preferably 1.59 or less, more preferably 1.57 or less, and further preferably 1.55 or less, 1.53 or less, 1.51 or less, 1.49 or less, 1.47 or less, 1.45 or less, 1.43 or less, 1.41 or less, 1.39 or less, 1.37 or less, 1.35 or less, 1.33 or less, 1.31 or less, 1.29 or less, 1.28 or less, 1.27 or less, 1.26 or less, 1.25 or less, and 1.24 or less.

Pb, as, cd, tl, be and Se are toxic, and therefore, it is preferable not to contain these elements, that is, to introduce these elements as glass components into the glass.

U, th and Ra are both radioactive elements, and therefore, it is preferable not to contain these elements, that is, to introduce these elements as glass components into the glass.

V, cr, mn, fe, co, ni, cu, pr, nd, pm, sm, eu, tb, dy, ho, er, tm and Ce are not preferable as elements contained in the glass for optical elements because they may cause an increase in coloring of the glass or may cause fluorescence. Therefore, it is preferable that these elements are not contained, that is, these elements are not introduced into the glass as glass components.

Sb and Sn are optional elements that function as a fining agent.

Sb when the mass of the glass is 100 ₂ O ₃ 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, 0.02% or less, or 0.01% or less in terms of mass fraction (%). On the other hand, sb was calculated as the mass of the glass taken as 100 ₂ O ₃ The Sb content may be 0.00% or more, or 0.00% by mass (%).

SnO when the mass of the glass is 100 ₂ 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, or 0.01% or less, in terms of mass fraction (%). On the other hand, snO when the glass mass is set to 100 ₂ The Sn content may be 0.00% or more, or 0.00% by mass (%).

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

The optical glass at least comprises O ^2- F (F) ^- As an anionic component.

From the viewpoint of increasing the refractive index of the glass and improving the thermal stability, O ^2- The content is more than 10.0%, preferably more than 15.0%, more than 17.5%, more than 20.0%, more than 22.5%, more than 25.0%, More preferably, the order of 27.5% 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, 53.0% or more, 54.0% or more, 55.0% or more, 56.0% or more, 57.0% or more, 58.0% or more, and 59.0% or more is the same.

In addition, from the viewpoints of maintaining low dispersion and suppressing the Tg rise of the glass, O ^2- The content is 95.0% or less, preferably 88.5% or less, more preferably 86.0% or less, 83.5% or less, 82.0% or less, 81.0% or less, 80.0% or less, 79.0% or less, 78.0% or less, and 77.0% or less.

F from the viewpoint of maintaining low dispersion and low Tg of the glass ^- The content is preferably 10.0% or more, more preferably 11.00% or more, and more preferably 12.00% or more, 13.00% or more, 14.00% or more, 15.00% or more, 16.00% or more, 17.00% or more, 18.00% or more, 19.00% or more, 20.00% or more, 21.00% or more, 22.00% or more, and 23.00% or more.

In addition, F is a component that enhances the thermal stability of the glass and suppresses volatilization of the glass during melting ^- The content is 90.0% or less, preferably 85.0% or less, more preferably 80.0% or less, 75.0% or less, 70.0% or less, 65.0% or less, 63.0% or less, 60.0% or less, 57.0% or less, 55.0% or less, 54.0% or less, 52.0% or less, 50.0% or less, 49.0% or less, 48.0% or less, 47.0% or less, 46.0% or less, 45.0% or less, 44.0% or less, and 43.0% or less.

As O removal ^2- F (F) ^- Other anionic components, e.g. Cl ^- 、Br ^- I ^- 。

Cl ^- The content may be, for example, 0.0% or more, 0.10% or more, or 0.20% or more, and may be, for example, 5.0% or less, 4.0% or less, 3.0% or less, 2.0% or less, 1.0% or less, or 0.50% or less.

Br ^- The content may be, for example, 0.0%,0.0% or more, more than 0.0%, 0.10% or more, 0.20% or more, and, for example, 5.0% or less, 4.0% or less, 3.0% or less, 2.0% or less, 1.0% or less, and 0.5% or less may be used.

I ^- The content may be, for example, 0.0% or more, 0.10% or more, or 0.20% or more, and may be, for example, 5.0% or less, 4.0% or less, 3.0% or less, 2.0% or less, 1.0% or less, or 0.5% or less.

< glass Properties >

(Abbe number vd)

The optical glass can exhibit low dispersion by having the glass composition. The Abbe number vd, which is an index of the dispersion, is represented by vd= (nd-1)/(nF-nC) using the refractive indices nd, nF, nC of d-ray, F-ray, and C-ray. The abbe number vd of the optical glass is preferably 70.00 or more, more preferably 70.50 or more, and further preferably 71.00 or more, 71.50 or more, 72.00 or more, 72.50 or more, and 73.00 or more in this order from the viewpoint of usefulness as a material for an optical element. The abbe number vd of the optical glass may be 82.00 or less, for example.

(refractive index nd)

From the viewpoint of the 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, or may be, 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 the present specification, "refractive index" means "refractive index nd", and refractive index nd means refractive index at a wavelength of 587.56 nm.

(glass transition temperature Tg)

The optical glass may have a low glass transition temperature by having the glass composition. The glass transition temperature Tg of the optical glass is preferably 350 ℃ or less, more preferably 340 ℃ or less, and further preferably 330 ℃ or less, 320 ℃ or less, 310 ℃ or less, 300 ℃ or less, 290 ℃ or less, 280 ℃ or less, 270 ℃ or less, 260 ℃ or less. The glass transition temperature Tg of the optical glass may be, for example, 150 ℃ or higher, 160 ℃ or higher, 170 ℃ or higher, 180 ℃ or higher, 190 ℃ or higher, or 200 ℃ or higher. The glass transition temperature Tg is determined by a method described later.

(specific gravity)

From the viewpoint of weight reduction of the optical element, the specific gravity of the optical glass is preferably low. 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. The specific gravity of the optical glass may be, for example, 2.55 or more, and the lower the specific gravity, the more preferable, and therefore the lower limit is not particularly limited.

(transmittance characteristics)

The optical glass has an external transmittance of 80% or more in terms of thickness of 10.0mm at a wavelength of 500nm to 1000 nm. "the external transmittance in terms of thickness of 10.0mm or more at a wavelength of 500nm to 1000 nm" means that the external transmittance in terms of thickness of 10.0mm in the entire wavelength range of 500nm to 1000nm is 80% or more. The optical glass may have an external transmittance of 80% to 100% in terms of a thickness of 10.0mm at a wavelength of 500nm to 1000 nm. The optical glass having such transmittance characteristics is useful as a material for optical elements. For example, by making Cu-free ²⁺ The glass as the cationic component can realize the above transmittance characteristics.

The transmittance characteristics of the glass were obtained by the following method.

The glass samples were processed to have planes which were parallel to each other and subjected to optical polishing, and the external transmittance at a wavelength of 500 to 1000nm was measured. The external transmittance also includes reflection loss of light on the sample surface.

In the case where the glass to be measured is not a glass having a reduced thickness, the thickness of the glass may be d, and the transmittance at each wavelength λ may be reduced by the following expression a, and the transmittance characteristics may be obtained by the conversion.

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 (%), T at wavelength λ ₀ (lambda): measured transmittance (%), d: converted thickness (mm), d ₀ : thickness of glass (mm), R (λ) = ((n (λ) -1)/(n (λ) +1)) ² Representing the reflectivity at wavelength λ, n (λ): refractive index at wavelength λ. Refractive index n (λ) at wavelength λ, refractive index measurement method for optical glass according to JIS B7071-1 "section 1 of japanese industrial standard (JIS standard): the minimum declination method ", the refractive index at each wavelength is measured.

Method for producing optical glass

The optical glass can be obtained as follows: phosphate, fluoride, oxide, carbonate, sulfate, nitrate, hydroxide, etc. as raw materials are weighed and blended so as to obtain a target glass composition, and then the raw materials are sufficiently mixed to prepare a mixed master batch, and the mixed master batch is heated, melted, defoamed, stirred in a melting vessel to prepare a uniform and bubble-free molten glass, which is molded to obtain an optical glass. Specifically, the composition can be produced by a known melting method.

[ glass raw material for press molding, optical element blank, and method for producing same ]

Another embodiment of the invention relates to:

a glass raw material for press molding comprising the optical glass; and

an optical element blank comprising the optical glass.

According to another embodiment of the present invention, there is also provided:

a method for producing a glass material for press molding, which comprises a step of molding the optical glass into a glass material for press molding;

a method for producing an optical element blank, comprising a step of press-molding the glass raw material for press-molding the optical glass by using a press-molding die; and

A method for producing an optical element blank, comprising a step of molding the optical glass into an optical element blank.

The optical element blank is an optical element base material which approximates the shape of the optical element to be inspected, and to which a polishing material (a surface layer to be removed by polishing) and, if necessary, a grinding material (a surface layer to be removed by grinding) are added to the shape of the optical element. The optical element is finished by grinding and polishing the surface of the optical element blank. In one embodiment, the optical element blank may be produced by a method of press molding a molten glass obtained by melting an appropriate amount of the glass (referred to as a direct press method (direct press method)). In another embodiment, the optical element blank may be produced by solidifying a molten glass obtained by melting an appropriate amount of the glass.

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

The press molding of the glass material for press molding can be performed by a known method of pressing the glass material for press molding heated and softened by a press molding die. The heating and the pressure molding can be carried out in the atmosphere. By reducing the strain in the glass by annealing after press molding, a uniform optical element blank can be obtained.

The glass material for press molding includes a material which is directly supplied to press molding for producing an optical element blank while maintaining its original state, called glass gob (glass gob), and also includes a material which is subjected to mechanical processing such as cutting, grinding, polishing, and the like, and then supplied to press molding after the glass gob for press molding is subjected to press molding. As a cutting method, the following method is included: forming grooves in a portion to be cut of a surface of a glass sheet by a method called scribing, applying a local pressure to the portion of the grooves from a back surface of a surface on which the grooves are formed, and cutting the glass sheet at the portion of the grooves; a method of cutting a glass plate with a cutter, and the like. Further, as grinding and polishing methods, barrel polishing and the like are mentioned.

For example, a glass raw material for press molding can be produced by casting molten glass into a mold, molding the glass into a glass plate, and cutting the glass plate into a plurality of glass sheets. Alternatively, a glass gob for press molding may be produced by molding an appropriate amount of molten glass. The optical element blank may be produced by press molding by reheating and softening a glass gob for press molding. A method of reheating, softening, and press-molding glass to produce an optical element blank is called a reheat press method (reheat press method) as opposed to a direct press method.

[ optical element and method for producing the same ]

Another embodiment of the invention relates to:

an optical element comprising the above optical glass.

The optical element is manufactured using the optical glass. In the optical element, one or more layers of a coating 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, there may be further provided:

the method for manufacturing an optical element includes a step of grinding and/or polishing the optical element blank to manufacture an optical element.

In the above-mentioned method for producing an optical element, mechanical processing such as grinding and polishing can be performed by a known method, and an optical element having high internal quality and surface quality can be obtained by sufficiently cleaning and drying the surface of the optical element after processing. Thus, an optical element formed of the optical glass can be obtained. As the optical element, various lenses such as a spherical lens, an aspherical lens, and a microlens, a prism, and the like can be exemplified.

The optical element formed of the optical glass is also suitable for use as a lens constituting a bonded optical element. As the joining optical element, an element in which lenses are joined to each other (joining lens), an element in which lenses are joined to prisms, and the like can be exemplified. For example, the bonded optical element may be fabricated by: the joining surfaces of the 2 optical elements to be joined are precisely processed (for example, spherical polishing processing) so that the shapes thereof are inverted, an ultraviolet-curable adhesive for joining the lenses is applied, and after joining, ultraviolet rays are irradiated through the lenses to cure the adhesive, thereby producing a joined optical element. A plurality of elements to be bonded can be manufactured using a plurality of glasses or the like having different abbe numbers vd, respectively, and bonded, thereby manufacturing an element suitable for compensating chromatic aberration.

Examples

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 >

The raw materials for introducing the respective components were weighed and thoroughly mixed to prepare the blended raw materials so as to obtain glass compositions shown in the following table, using respective phosphates, fluorides, nitrates, sulfates, carbonates, hydroxides, oxides, boric acid, and the like as raw materials.

The raw materials were placed in a platinum crucible, heated in a furnace set at 700 to 1100 ℃ and melted for 90 minutes. After the molten glass was stirred and homogenized, the molten glass was poured into a preheated mold, naturally cooled to a temperature around the glass transition temperature, immediately placed in an annealing furnace, and after the molten glass was kept at the temperature around the glass transition temperature for about 30 minutes, the molten glass was slowly cooled at a slow cooling rate of-30 ℃/hour for 4 hours, and then naturally cooled to room temperature in the furnace, whereby optical glasses of sample nos. 1 to 88 shown in the following tables were obtained.

Comparative examples A and B

The raw materials for introducing the respective components were weighed and thoroughly mixed to prepare the blended raw materials so as to obtain glass compositions shown in the following table, using respective phosphates, fluorides, nitrates, sulfates, carbonates, hydroxides, oxides, boric acid, and the like as raw materials.

The raw materials were placed in a platinum crucible, heated in a furnace set at 700 to 1100 ℃ and melted for 90 minutes. After the molten glass was stirred and homogenized, the molten glass was poured into a preheated mold, naturally cooled to a temperature around the glass transition temperature, immediately placed in an annealing furnace, and after the molten glass was kept at the temperature around the glass transition temperature for about 30 minutes, the molten glass was slowly cooled at a slow cooling rate of-30 ℃/hour for 4 hours, and then naturally cooled to room temperature in the furnace, whereby optical glasses of comparative example a and comparative example B shown in the following tables were obtained. 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).

< evaluation of physical Properties >

The physical properties of each optical glass shown in the following table were measured by the methods shown below.

(1) Refractive index nd, abbe number vd

For each optical glass, the refractive index nd and the abbe number vd were measured by a refractive index measurement method standard in the japan optical nitroindustry. In comparative example a, since glass was devitrified, the refractive index nd and the abbe number vd could not be measured.

(2) Glass transition temperature Tg

Glass was sufficiently pulverized in a mortar, and a glass transition temperature Tg was measured by using a differential scanning calorimeter analysis apparatus (DSC 3300 SA) manufactured by NETZSCH JAPAN, using a platinum cell as a sample container, and setting the temperature rise rate to 10 ℃/min.

(3) Specific gravity

Specific gravity was measured by archimedes method.

(4) Transmittance characteristics

Test pieces were cut out from the obtained glass, mirror polished on both sides, and polished to have planes parallel to each other and optically polished so that the thickness was 10.0mm, and then external transmittance at a wavelength of 500 to 1000nm was measured using a spectrophotometer.

In any of sample Nos. 1 to 88, comparative example A and comparative example B, it was confirmed that the external transmittance at a wavelength of 500nm to 1000nm was 80% or more and 100% or less at a thickness of 10.0 mm.

< evaluation of thermal stability >

For each of samples nos. 1 to 88, comparative example a and comparative example B, corresponding phosphate, fluoride, nitrate, sulfate, carbonate, hydroxide, oxide, boric acid, and the like were used as raw materials for introducing the respective components so as to have glass compositions shown in the following table, and the raw materials were weighed and thoroughly mixed to prepare blended raw materials.

The raw materials were placed in a platinum crucible, heated in a furnace set at 700 to 1100 ℃ and melted for 90 minutes. After the molten glass was homogenized by stirring, the molten glass was cast into a mold, molded, and slowly cooled to obtain a glass sample in the form of a block.

For the obtained glass sample, observation of crystals in the glass was performed by an optical microscope. The magnification of the optical microscope was set to 40 to 100 times. A was determined to be A when no crystals were confirmed in the glass block, and was found to be 1cm on average ³ When 1 or more and 15 or less crystals were confirmed, the crystals were judged as B, and the crystals were measured at an average of 1cm ³ C was determined when 16 or more and 40 or less crystals were observed, and the average of C was 1cm ³ When more than 40 crystals were confirmed, it was judged as D. As for A, B, C, the thermal stability becomes higher in the order of c→b→a, and the thermal stability of a is highest. In the case of A, B, C, the internal quality of the crystal number contained in the glass is within an allowable range. The glass having a result of the judgment of D was poor in heat stability, and was inferior in internal quality in production.

As shown in the following table, it was confirmed that the glasses of sample nos. 1 to 88 were excellent in thermal stability (determination result A, B or C).

Example 2

Glass gobs (glass gobs) for press molding were produced using the various glasses obtained in example 1. The glass gob was heated and softened in the atmosphere, and was press-molded with a press mold to prepare a lens blank (optical element blank). The manufactured lens blank was taken out of the press molding die, annealed, and subjected to mechanical processing including polishing, to manufacture a spherical lens formed of various glasses manufactured in example 1.

Example 3

A desired amount of the molten glass produced in example 1 was press-molded with a press mold to produce a lens blank (optical element blank). The manufactured lens blank was taken out of the press molding die, annealed, and subjected to mechanical processing including polishing, to manufacture a spherical lens formed of various glasses manufactured in example 1.

Example 4

The glass gob (optical element blank) produced by solidifying the molten glass produced in example 1 was annealed, and a mechanical process including polishing was performed to produce spherical lenses formed from the various glasses produced in example 1.

Finally, the above embodiments are summarized.

[1] An optical glass, which has a glass composition expressed as cation%,

S ⁶⁺ The content exceeds 0.0 cation% and is 30.0 cation% or less,

Al ³⁺ the content exceeds 0.0 cation% and is 30.0 cation% or less,

P ⁵⁺ the content is 5.0 to 50.0 cation%,

Li ⁺ the content is 0.0 cation% or more and 51.0 cation% or less,

Na ⁺ the content is more than 0.0 cation% and less than 44.0 cation%,

K ⁺ the content is 0.0 to 45.0 cation%,

Li ⁺ 、Na ⁺ 、K ⁺ cs ⁺ Is the total content R of ⁺ Is more than 5.0 percent of cation,

be is carried out ²⁺ 、Mg ²⁺ 、Ca ²⁺ 、Sr ²⁺ Ba and Ba ²⁺ The total content of (2) is R ²⁺ ，R ²⁺ Relative to Al ³⁺ And R is R ²⁺ Cation ratio (R) ²⁺ /(Al ³⁺ +R ²⁺ ) Is not more than 0.56 and is not more than,

in the glass composition expressed in anion%,

O ^2- the content of the anionic component is more than 10.0 percent and less than 95.0 percent,

F ^- The content is 10.0-90.0 anion%,

the optical glass has an external transmittance of 80% or more in terms of thickness of 10.0mm at a wavelength of 500nm to 1000 nm.

[2] The optical glass according to [1], wherein,

P ⁵⁺ content relative to Al ³⁺ And P ⁵⁺ Cation ratio (P) ⁵⁺ /(Al ³⁺ +P ⁵⁺ ) 0.30 to 0.85).

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

Li ⁺ content relative to R ⁺ And R is R ²⁺ Is a total cation ratio (Li ⁺ /(R ⁺ +R ²⁺ ) More than 0.00 and less than 1.00.

[4] The optical glass according to any one of [1] to [3], wherein,

R ⁺ relative to Al ³⁺ And P ⁵⁺ Cation ratio (R) ⁺ /(Al ³⁺ +P ⁵⁺ ) 0.93 or more.

[5] The optical glass according to any one of [1] to [4], wherein,

Li ⁺ and K is equal to ⁺ Relative to Al ³⁺ And P ⁵⁺ Cation ratio ((Li) ⁺ +K ⁺ )/(Al ³⁺ +P ⁵⁺ ) 0.56 or more).

[6] The optical glass according to any one of [1] to [5], wherein,

Li ⁺ with Na and Na ⁺ Relative to Li ⁺ And K is equal to ⁺ Cation ratio ((Li) ⁺ +Na ⁺ )/(Li ⁺ +K ⁺ ) 0.50 or more and 1.59 or less.

[7] The optical glass according to any one of [1] to [6], wherein the glass transition temperature Tg is 150℃or more and 350℃or less.

[8] The optical glass according to any one of [1] to [7], wherein the Abbe number vd is 70.00 or more and 82.00 or less.

[9] The optical glass according to [1], wherein,

P ⁵⁺ content relative to Al ³⁺ And P ⁵⁺ Cation ratio (P) ⁵⁺ /(Al ³⁺ +P ⁵⁺ ) More than 0.30 and less than 0.85,

Li ⁺ content relative to R ⁺ And R is R ²⁺ Is a total cation ratio (Li ⁺ /(R ⁺ +R ²⁺ ) More than 0.00 and less than 1.00,

R ⁺ relative to Al ³⁺ And P ⁵⁺ Cation ratio (R) ⁺ /(Al ³⁺ +P ⁵⁺ ) More than 0.93 percent,

Li ⁺ and K is equal to ⁺ Relative to Al ³⁺ And P ⁵⁺ Cation ratio ((Li) ⁺ +K ⁺ )/(Al ³⁺ +P ⁵⁺ ) Is more than 0.56), is not less than 0.56,

Li ⁺ with Na and Na ⁺ Relative to Li ⁺ And K is equal to ⁺ Cation ratio ((Li) ⁺ +Na ⁺ )/(Li ⁺ +K ⁺ ) More than 0.50 and less than 1.59,

the glass transition temperature Tg of the optical glass is 150-350 ℃ and Abbe number vd is 70.00-82.00.

[10] An optical element comprising the optical glass of any one of [1] to [9 ].

It should be understood that the embodiments disclosed herein are illustrative in all respects and are not to be construed as limiting. The scope of the invention is indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.

For example, the optical glass according to one embodiment of the present invention can be obtained by adjusting the composition described in the specification with respect to the glass composition of the above example.

It is needless to say that 2 or more of the matters exemplified in the specification or described as preferable ranges may be arbitrarily combined.

Claims (10)

1. An optical glass, wherein in a glass composition expressed as cation%,

S ⁶⁺ the content exceeds 0.0 cation% and is 30.0 cation% or less,

Al ³⁺ at a content of more than 0.0 cationThe content of the cation is 30.0% or less,

P ⁵⁺ The content is 5.0 to 50.0 cation%,

Li ⁺ the content is 0.0 cation% or more and 51.0 cation% or less,

Na ⁺ the content is more than 0.0 cation% and less than 44.0 cation%,

K ⁺ the content is 0.0 to 45.0 cation%,

Li ⁺ 、Na ⁺ 、K ⁺ cs ⁺ Is the total content R of ⁺ Is more than 5.0 percent of cation,

be is carried out ²⁺ 、Mg ²⁺ 、Ca ²⁺ 、Sr ²⁺ Ba and Ba ²⁺ The total content of (2) is R ²⁺ ，R ²⁺ Relative to Al ³⁺ And R is R ²⁺ Cation ratio (R) ²⁺ /(Al ³⁺ +R ²⁺ ) Is not more than 0.56 and is not more than,

in the glass composition expressed in anion%,

O ^2- the content is 10.0-95.0 anion%,

F ^- the content is 10.0-90.0 anion%,

the optical glass has an external transmittance of 80% or more in terms of thickness of 10.0mm at a wavelength of 500nm to 1000 nm.

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

P ⁵⁺ content relative to Al ³⁺ And P ⁵⁺ Cation ratio (P) ⁵⁺ /(Al ³⁺ +P ⁵⁺ ) 0.30 to 0.85).

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

Li ⁺ content relative to R ⁺ And R is R ²⁺ Is a total cation ratio (Li ⁺ /(R ⁺ +R ²⁺ ) More than 0.00 and less than 1.00.

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

R ⁺ relative to Al ³⁺ And P ⁵⁺ Cation ratio (R) ⁺ /(Al ³⁺ +P ⁵⁺ ) 0.93 or more.

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

Li ⁺ and K is equal to ⁺ Relative to Al ³⁺ And P ⁵⁺ Cation ratio ((Li) ⁺ +K ⁺ )/(Al ³⁺ +P ⁵⁺ ) 0.56 or more).

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

Li ⁺ with Na and Na ⁺ Relative to Li ⁺ And K is equal to ⁺ Cation ratio ((Li) ⁺ +Na ⁺ )/(Li ⁺ +K ⁺ ) 0.50 or more and 1.59 or less.

7. The optical glass according to claim 1, which has a glass transition temperature Tg of 150 ℃ or more and 350 ℃ or less.

8. The optical glass according to claim 1, wherein the Abbe number vd is 70.00 or more and 82.00 or less.

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

P ⁵⁺ content relative to Al ³⁺ And P ⁵⁺ Cation ratio (P) ⁵⁺ /(Al ³⁺ +P ⁵⁺ ) More than 0.30 and less than 0.85,

Li ⁺ content relative to R ⁺ And R is R ²⁺ Is a total cation ratio (Li ⁺ /(R ⁺ +R ²⁺ ) More than 0.00 and less than 1.00,

R ⁺ relative to Al ³⁺ And P ⁵⁺ Cation ratio (R) ⁺ /(Al ³⁺ +P ⁵⁺ ) More than 0.93 percent,

Li ⁺ and K is equal to ⁺ Relative to Al ³⁺ And P ⁵⁺ Cation ratio ((Li) ⁺ +K ⁺ )/(Al ³⁺ +P ⁵⁺ ) Is more than 0.56), is not less than 0.56,

Li ⁺ with Na and Na ⁺ Relative to Li ⁺ And K is equal to ⁺ Cation ratio ((Li) ⁺ +Na ⁺ )/(Li ⁺ +K ⁺ ) More than 0.50 and less than 1.59,

the glass transition temperature Tg of the optical glass is 150 ℃ to 350 ℃ and the Abbe number vd is 70.00 to 82.00.

10. An optical element comprising the optical glass of any one of claims 1 to 9.