JP6143706B2 - Optical glass, optical element and preform - Google Patents

Description

  The present invention relates to an optical glass, an optical element, and a preform.

  In recent years, the digitization and high definition of devices that use optical systems are rapidly progressing, and the accuracy of optical elements such as lenses used in various optical devices such as digital cameras and video cameras is increasing. The demand for weight reduction is increasing.

  In particular, there is an increasing demand for glass having a high refractive index (nd) and a high Abbe number (νd), which can reduce the thickness and weight of optical elements. As such a high refractive index and low dispersion glass, for example, glass represented by Patent Documents 1 to 5 is known as an optical glass having low dispersibility having an Abbe number of 70 or more.

JP 2005-247658 A JP 2010-059019 A JP 2011-116649 A JP 2011-126782 A

  However, the optical glasses described in Patent Documents 1 to 4 have a low refractive index. Therefore, development of an optical glass having a high refractive index and a high Abbe number is desired.

  The present invention has been made in view of the above problems, and its object is to provide an optical glass having a desired high refractive index and a high Abbe number, and a preform and an optical system using the optical glass. It is to provide an element.

  The present inventors have intensively studied to solve the above problems, and have completed the present invention. Specifically, the present invention provides the following.

(1) An optical glass containing P ⁵⁺ , Al ³⁺ , Sr ²⁺ and Ba ²⁺ as a cation component, O ²⁻ and F ⁻ as an anion component, and having a refractive index (nd) of 1.50 or more.

(2) In cation% (mol%) display,
P ⁵⁺ from 20.0 to 50.0%,
Al ³⁺ 15.0-40.0%,
Sr2 ⁺ is 5.0-30.0% and Ba2 ⁺ is 10.0-50.0%.
The optical glass described in (1).

(3) The total amount of Al ³⁺ and Ba ²⁺ content (cation%) Al ³⁺ + Ba ²⁺ is 30.0% or more and 60.0% or less in terms of cation% (mol%) (1) or (2) The optical glass described.

(4) The total amount of P ⁵⁺ , Al ³⁺ and Ba ²⁺ content (cation%) in terms of cation% (mol%) (P ⁵⁺ + Al ³⁺ + Ba ²⁺⁾ is 50.0% or more and 95.0% or less (1 ) To (3).

(5) In any one of (1) to (4), the ratio Ba ²⁺ / Mg ²⁺ of the Ba ²⁺ content and the Mg ²⁺ content is 1.0 or more and 40.0 or less in terms of cation% (mol%). Optical glass.

(6) In terms of cation% (mol%),
Mg ²⁺ from 0 to 20.0%,
0 to 20.0% of Ca ²⁺
The optical glass according to any one of (1) to (5).

(7) In terms of cation% (mol%), the ratio of Ba ²⁺ content and Al ³⁺ content to Mg ²⁺ content (Ba ²⁺ + Al ³⁺ ) / Mg ²⁺ is 3.0 or more and 70.0 or less (1 ) To (6).

(8) In terms of cation% (mol%),
La ³⁺ content is 0 to 10.0%,
The content of Gd ³⁺ is 0 to 10.0%,
Y ³⁺ content is 0 to 10.0%,
0 to 10.0% content of Yb ³⁺ ,
Lu ³⁺ content is 0 to 10.0%
The optical glass according to any one of (1) to (7).

(9) In terms of cation% (mol%), the total content of La ³⁺ , Gd ³⁺ , Y ³⁺ and Yb ³⁺ (Ln ³⁺ : cation%) is 20.0% or less (1) to (8) Any one of the optical glasses.

(10) In terms of anion% (mol%),
O ²⁻ 30.0-70.0%
F ^- a 30.0 to 70.0%
The optical glass according to any one of (1) to (9).

  (11) The optical glass according to any one of (1) to (10), which has an Abbe number (νd) of 70 or more.

  (12) The optical glass according to any one of (1) to (11), wherein the specific gravity is 4.50 or less.

  (13) An optical element made of the optical glass according to any one of (1) to (12).

  (14) A preform for polishing and / or precision press molding comprising the optical glass according to any one of (1) to (12)

  (15) An optical element obtained by precision pressing the preform described in (14).

  According to the present invention, it is possible to provide an optical glass having a desired high refractive index and Abbe number, and a preform and an optical element using the optical glass.

The optical glass of the present invention contains P ⁵⁺ , Al ³⁺ , Sr ²⁺ and Ba ²⁺ as cation components, O ²⁻ and F ⁻ as anion components, and has a refractive index (nd) of 1.50 or more. . By containing the above components as the cation component and the anion component and adjusting the content of the above components and other components, it is possible to obtain a high refractive index of the glass while maintaining a high Abbe number. .

  Hereinafter, the optical glass of the present invention will be described. The present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention. In addition, although description may be abbreviate | omitted about the location where description overlaps, the meaning of description is not limited.

<Glass component>
Each component which comprises the optical glass of this invention is demonstrated.
In the present specification, unless otherwise specified, the content of each component is expressed in terms of cation% or anion% based on the molar ratio. Here, “cation%” and “anion%” (hereinafter sometimes referred to as “cation% (mol%)” and “anion% (mol%)”) are glass constituents of the optical glass of the present invention. Is divided into a cation component and an anion component, and the total ratio is 100 mol% in each, and the content of each component contained in the glass is described.
In addition, since the ionic value of each component uses only a representative value for convenience, it is not distinguished from other ionic values. The ionic valence of each component present in the optical glass may be other than the representative value. For example, since P is normally present in the glass in a state where the ionic valence is pentavalent, it is expressed as “P ⁵⁺ ” in this specification, but may exist in other ionic valence states. Thus, strictly speaking, in the present specification, each component is treated as being present in the glass with a representative ionic valence even if it exists in another ionic valence state.

[Cation component]
P ⁵⁺ is a glass-forming component, and is an essential component that can increase the devitrification resistance of the glass by containing 20.0% or more in particular. Therefore, the content of P ⁵⁺ is preferably 20.0%, more preferably 22.0%, still more preferably 25.0%, still more preferably 30.0%.
On the other hand, by setting the content of P ⁵⁺ to 50.0% or less, a decrease in refractive index and Abbe number due to P ⁵⁺ can be suppressed, and a decrease in chemical durability can be suppressed. Accordingly, the upper limit of the content of P ⁵⁺ is preferably 50.0%, more preferably 45.0%, and even more preferably 40.0%.
As P ⁵⁺ , Al (PO ₃ ) ₃ , Ca (PO ₃ ) ₂ , Ba (PO ₃ ) ₂ , Zn (PO ₃ ) ₂ , BPO ₄ , H ₃ PO _{4 and the} like can be used as raw materials.

By containing 10.0% or more, Al ³⁺ is an essential component that contributes to the formation of a skeleton having a fine structure of glass, thereby improving devitrification resistance and reducing the degree of wear. Therefore, the content of Al ³⁺ is preferably 10.0%, more preferably 13.0%, and still more preferably 15.0%.
On the other hand, by setting the content of Al ³⁺ to 40.0% or less, a decrease in refractive index and Abbe number due to Al ³⁺ and an increase in glass transition point and yield point can be suppressed. Therefore, the upper limit of the content of Al ³⁺ is preferably 40.0%, more preferably 35.0%, still more preferably 30.0%, and still more preferably 25.0%.
Al ³⁺ can use Al (PO ₃ ) ₃ , AlF ₃ , Al ₂ O ₃ or the like as a raw material.

Sr ²⁺ is an essential component that increases the devitrification resistance of the glass and suppresses the decrease in the refractive index by containing 5.0% or more. Note that the Sr ²⁺ content is preferably 5.0%, more preferably 7.5%, and still more preferably 10.0%.
On the other hand, by setting the Sr ²⁺ content to 30.0% or less, glass devitrification and a decrease in refractive index due to excessive Sr ²⁺ content can be suppressed. Therefore, the Sr ²⁺ content is preferably 30.0% or less, more preferably 24.0% or less, and even more preferably 21.0% or less.
Sr ²⁺ can use Sr (NO ₃ ) ₂ , SrF ₂ or the like as a raw material.

Ba ²⁺ is an essential component containing 10.0% or more to lower the glass transition point and yield point, increase devitrification resistance, increase the Abbe number, and increase the refractive index. Accordingly, the Ba ²⁺ content is preferably 10.0%, more preferably 15.0%, still more preferably 17.5%, and even more preferably 20.0%.
On the other hand, when the content of ^{Ba 2+} below 50.0%, suppressed the decrease in resistance to devitrification of the glass due to excessive content of ^{Ba 2+.} Accordingly, the upper limit of the Ba ²⁺ content is preferably 50.0%, more preferably 45.0%, still more preferably 40.0%, still more preferably 35.0%, and even more preferably 32.5%. As Ba ²⁺ , Ba (PO ₃ ) ₂ , BaCO ₃ , Ba (NO ₃ ) ₂ , BaF _{2 and the} like can be used as raw materials.

In the optical glass of the present invention, the total amount (cation%) of the P ⁵⁺ content and the Al ³⁺ content is preferably 40.0% or more and 60.0% or less.
In particular, the devitrification resistance is enhanced by setting the total amount to 40.0% or more. Therefore, the total amount of P ⁵⁺ and Al ³⁺ is preferably 40.0%, more preferably 45.0%, and still more preferably 47.0%.
On the other hand, by making this total amount 60.0% or less, it is possible to suppress a decrease in refractive index and Abbe number. Therefore, the total amount of P ⁵⁺ and Al ³⁺ is preferably 60.0%, more preferably 58.0%, still more preferably 55.0%.

The total amount of Al ³⁺ and Ba ²⁺ is preferably 30.0% or more and 60.0% or less.
In particular, when the total amount is 30.0% or more, the refractive index can be increased and the devitrification resistance can be increased. Therefore, the total amount of Al ³⁺ and Ba ²⁺ is preferably 30.0%, more preferably 35.0%, even more preferably 38.0%, even more preferably 40.0%, and even more preferably 45.0%. Is the lower limit.
On the other hand, by making this total amount 60.0% or less, a decrease in the Abbe number of the glass can be suppressed and devitrification resistance can be enhanced. Therefore, the total amount of Al ³⁺ and Ba ²⁺ is preferably 60.0%, more preferably 57.0%, and still more preferably 55.0%.

The total amount of P ⁵⁺ , Al ³⁺ and Ba ²⁺ is preferably 50.0% or more and 95.0% or less.
In particular, when the total amount is 50.0% or more, the refractive index can be increased and the devitrification resistance can be improved. Therefore, the total amount of P ⁵⁺ , Al ³⁺ and Ba ²⁺ is preferably 50.0%, more preferably 55.0%, still more preferably 60.0%, and even more preferably 65.0%.
On the other hand, devitrification resistance is improved by making this total amount 95.0% or less. Therefore, the total amount of P ⁵⁺ , Al ³⁺ and Ba ²⁺ is preferably 95.0%, more preferably 90.0%, still more preferably 87.5%, and still more preferably 85.0%.

The total amount of Sr ²⁺ and Ba ²⁺ is preferably 30.0% or more and 60.0% or less.
In particular, when the total amount is 30.0% or more, the refractive index can be increased and the devitrification resistance can be increased. Therefore, the total amount of Sr ²⁺ and Ba ²⁺ is preferably 30.0%, more preferably 35.0%, and still more preferably 40.0%.
On the other hand, by making this total amount 60.0% or less, a decrease in the Abbe number of the glass can be suppressed and devitrification resistance can be enhanced. Therefore, the total amount of Al ³⁺ and Ba ²⁺ is preferably 60.0%, more preferably 55.0%, and still more preferably 50.0%.

Mg ²⁺ is an optional component that can enhance the devitrification resistance of the glass when it is contained in an amount of more than 0%. Therefore, the Mg ²⁺ content is preferably more than 0%, more preferably 0.5%, and still more preferably 1.0%.
On the other hand, by setting the Mg ²⁺ content to 20.0% or less, glass devitrification and a decrease in refractive index due to excessive Mg ²⁺ content can be suppressed. Therefore, the Mg ²⁺ content is preferably 20.0% or less, more preferably 17.0% or less, and even more preferably 15.0% or less. The Mg ²⁺ content is preferably 10.0% or less, more preferably 8.0% or less.
Mg ²⁺ may be used MgO, the MgF ₂ or the like as a raw material.

Ca ²⁺ is an optional component that can enhance the devitrification resistance of the glass when it is contained in excess of 0%.
On the other hand, by making the content of Ca ²⁺ 20.0% or less, it is possible to suppress the devitrification resistance and the refractive index of the glass due to excessive Ca ²⁺ content. Therefore, the Ca ²⁺ content is preferably 20.0% or less, more preferably 15.0% or less, and still more preferably 10.0% or less. The Ca ²⁺ content is preferably 8.0% or less, more preferably 5.0% or less, and even more preferably 3.0% or less.
Ca ²⁺ can use Ca (PO ₃ ) ₂ , CaCO ₃ , CaF ₂ or the like as a raw material.

In the optical glass of the present invention, the ratio of the Mg ²⁺ content to the Ba ²⁺ content is preferably 1.0 or more and 40.0 or less. Thereby, the refractive index of glass can be raised and devitrification resistance is improved. Therefore, the cation ratio (Ba ²⁺ / Mg ²⁺ ) is preferably 1.0, more preferably 2.0, and still more preferably 3.0.
On the other hand, the upper limit of this ratio is preferably 40.0, more preferably 35.0, and still more preferably 32.0.

The ratio of the total amount of Ba ²⁺ and Al ³⁺ to the Mg ²⁺ content is preferably 3.0 or more and 70.0 or less. Thereby, the refractive index of glass can be raised and devitrification resistance is improved. Therefore, the cation ratio (Ba ²⁺ + Al ³⁺ ) / Mg ²⁺ is preferably 3.0, more preferably 4.0, still more preferably 5.0, and still more preferably 6.0.
On the other hand, the upper limit of this ratio is preferably 70.0, more preferably 65.0, and still more preferably 60.0.

Alkaline earth metal means one or more selected from the group consisting of Sr ²⁺ , Ba ²⁺ , Mg ²⁺ and Ca ²⁺ . One or more selected from the group consisting of Sr ²⁺ , Ba ²⁺ , Mg ²⁺ and Ca ²⁺ may be represented as R ²⁺ .
In addition, the total content of R ²⁺ means the total content of one or more of these four ions (for example, Sr ²⁺ + Ba ²⁺ + Mg ²⁺ + Ca ²⁺ ).

Here, the total content of R ²⁺ is preferably 30.0% or more and 70.0% or less.
In particular, glass containing higher devitrification resistance can be obtained by containing 30.0% or more of R ²⁺ . Therefore, the total content of R ²⁺ is preferably 30.0%, more preferably 35.0%, still more preferably 40.0%, and even more preferably 42.0%.
On the other ^hand, when the content of ^{R 2+} below ^70.0, can be reduced devitrification due to excessive content of the ^{R 2+.} Therefore, the total content of R ²⁺ is preferably 70.0%, more preferably 60.0%, and still more preferably 55.0%.

La ³⁺ is an optional component that can increase the devitrification resistance while maintaining a high refractive index and a high Abbe number when it contains more than 0%. Accordingly, the La ³⁺ content is preferably more than 0, more preferably 0.5%, and still more preferably 1.0%.
On the other hand, by setting the La ³⁺ content to 10.0% or less, devitrification due to excessive inclusion of these components can be reduced, and the material cost and specific gravity of the glass can be reduced. This also suppresses the increase in glass transition point and yield point. Accordingly, the La ³⁺ content is preferably 10.0% or less, more preferably 8.0% or less, and even more preferably 5.0% or less.
La ³⁺ can use La ₂ O ₃ , LaF ₃ or the like as a raw material.

Gd ³⁺ is an optional component that can increase the devitrification resistance while maintaining a high refractive index and a high Abbe number when it contains more than 0%. Therefore, the content of Gd ³⁺ is preferably more than 0%, more preferably 0.5%, and still more preferably 1.0%.
On the other hand, by setting the content of Gd ³⁺ to 10.0% or less, devitrification due to excessive inclusion of these components can be reduced, and the material cost and specific gravity of glass can be reduced. This also suppresses the increase in glass transition point and yield point. Therefore, the content of Gd ³⁺ is preferably 10.0% or less, more preferably 8.0% or less, and still more preferably 5.0% or less.
Gd ³⁺ can use Gd ₂ O ₃ , GdF ₃ or the like as a raw material.

Y ³⁺ is an optional component that can increase the devitrification resistance while maintaining a high refractive index and a high Abbe number when it contains more than 0%. Therefore, the content of Y ³⁺ is preferably more than 0%, more preferably 0.5%, and still more preferably 1.0%.
On the other hand, by setting the content of Y ³⁺ to 10.0% or less, devitrification due to excessive inclusion of these components can be reduced, and the material cost and specific gravity of glass can be reduced. This also suppresses the increase in glass transition point and yield point. Therefore, the content of Y ³⁺ is preferably 10.0% or less, more preferably 8.0% or less, and still more preferably 5.0% or less.
Y ³⁺ can use Y ₂ O ₃ , YF ₃ or the like as a raw material.

Yb ³⁺ is an optional component that can increase the devitrification resistance while maintaining a high refractive index and a high Abbe number when it contains more than 0%. Therefore, the Yb ³⁺ content is preferably more than 0%, more preferably 0.5%, and still more preferably 1.0%.
On the other hand, by setting the content of Yb ³⁺ to 10.0% or less, devitrification due to excessive inclusion of these components can be reduced, and the material cost and specific gravity of glass can be reduced. This also suppresses the increase in glass transition point and yield point. Therefore, the content of Yb ³⁺ is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less, still more preferably 2.5% or less, and still more preferably 1.0%. % Or less.
Yb ³⁺ can use Yb ₂ O ₃ , YbF ₃ or the like as a raw material.

Lu ³⁺ is an optional component that can enhance devitrification resistance while maintaining a high refractive index and a high Abbe number when it contains more than 0%. Therefore, the content of Lu ³⁺ is preferably more than 0%, more preferably 0.5%, and still more preferably 1.0%.
On the other hand, by setting the Lu ³⁺ content to 10.0% or less, devitrification due to excessive inclusion of these components can be reduced, and the material cost and specific gravity of the glass can be reduced. This also suppresses the increase in glass transition point and yield point. Accordingly, the Lu ³⁺ content is preferably 10.0% or less, more preferably 8.0% or less, and even more preferably 5.0% or less.
Lu ³⁺ can use Lu ₂ O ₃ , LuF ₃ or the like as a raw material.

Ln ³⁺ means at least one selected from the group consisting of La ³⁺ , Gd ³⁺ , Y ³⁺ , Yb ³⁺ and Lu ³⁺ . The total content of Ln ³⁺ may represent the total content of these five ions (La ³⁺ + Gd ³⁺ + Y ³⁺ + Yb ³ + Lu ³⁺ ).
By making the total content of Ln ³⁺ exceed 0%, devitrification resistance can be enhanced while maintaining a high refractive index and a high Abbe number. Therefore, the total content of Ln ³⁺ is preferably more than 0%, more preferably 0.5%, and still more preferably 1.0%.
On the other hand, by setting the total content of Ln ³⁺ to 20.0% or less, devitrification due to excessive inclusion of Ln ³⁺ can be reduced, and the material cost and specific gravity of glass can be reduced. Therefore, the total content of Ln ³⁺ is preferably 20.0% or less, more preferably 15.0% or less, still more preferably 10.0% or less, still more preferably 7.5% or less, and even more preferably 5. 0% or less.

Li ⁺ , Na ⁺ and K ⁺ are optional components that can lower the glass transition point while maintaining high devitrification resistance during glass formation when contained in excess of 0%.
On the other hand, by setting the content of one or more of Li ⁺ , Na ⁺ and K ⁺ to 10.0% or less, a decrease in refractive index and a deterioration in chemical durability can be suppressed. Therefore, the content of each of Na ^{+ and} K ⁺ is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less, and even more preferably 2.0% or less. .
Li ⁺ , Na ⁺ and K ⁺ are Li ₂ CO ₃ , LiNO ₃ , LiF, Na ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ SiF ₆ , K ₂ CO ₃ , KNO ₃ , KF, KHF ₂ , K ₂ SiF ₆ or the like can be used.

In the present invention, Rn ⁺ means at least one selected from the group consisting of Li ⁺ , Na ⁺ and K ⁺ . In addition, the total content of Rn ⁺ may represent the total content of these three ions (Li ⁺ + Na ⁺ + K ⁺ ).
In particular, by making the total content of Rn ⁺ 10.0% or less, it is possible to suppress a decrease in the refractive index of glass and a deterioration in chemical durability. Therefore, the total content of Rn ⁺ is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less, and even more preferably 2.0% or less.

Si ⁴⁺ is an optional component that can increase the devitrification resistance of the glass, increase the refractive index, and decrease the degree of wear when it contains more than 0%.
On the other hand, when the content of ^{Si 4+} to 10.0% or less, can be reduced devitrification due to excessive content of ^{Si 4+.} Therefore, the Si ⁴⁺ content is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less, and even more preferably 3.0% or less.
Si ⁴⁺ can use SiO ₂ , K ₂ SiF ₆ , Na ₂ SiF ₆ or the like as a raw material.

B ³⁺ is an optional component that can increase the refractive index and devitrification resistance of the glass when it is contained in an amount of more than 0%.
On the other hand, deterioration of chemical durability can be suppressed by setting the content of B ³⁺ to 15.0% or less. Therefore, the content of B ³⁺ is preferably 15.0% or less, more preferably 10.0% or less, still more preferably 8.0% or less, and even more preferably 5.0% or less.
B ³⁺ can be used _{H 3 BO 3, Na 2 B} 4 O 7, BPO 4 , etc. as a raw material.

Ge ⁴⁺ is an optional component that can increase the refractive index of the glass and increase the resistance to devitrification when it contains more than 0%.
On the other hand, when the content of Ge ⁴⁺ is set to 10.0% or less, the content of expensive Ge ⁴⁺ decreases, so that the material cost of glass can be reduced. Therefore, the content of Ge ⁴⁺ is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less, and even more preferably 3.0% or less.
For Ge ⁴⁺ , GeO ₂ or the like can be used as a raw material.

Nb ⁵⁺ , Ti ⁴⁺ and W ⁶⁺ are optional components that can increase the refractive index of the glass when contained over 0%. In addition, Nb ⁵⁺ is also a component capable of enhancing chemical durability when it is contained in an amount of more than 0%. Moreover, ^{W6 +} is also a component which can make a glass transition point low, when it contains more than 0%.
On the other hand, by making each content of Nb ⁵⁺ , Ti ⁴⁺ and W ⁶⁺ 10.0% or less, a decrease in Abbe number can be suppressed, and a decrease in visible light transmittance due to glass coloring can be suppressed. Therefore, the content of each of Nb ⁵⁺ , Ti ⁴⁺ and W ⁶⁺ is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less, and even more preferably 3.0%. The following.
Nb ²⁺ , Ti ⁴⁺ and W ⁶⁺ can use Nb ₂ O ₅ , TiO ₂ , WO ₃ or the like as a raw material.

Zr ⁴⁺ is an optional component that can increase the refractive index of glass when it contains more than 0%.
On the other hand, by making the content of Zr ⁴⁺ 10.0% or less, the striae of the glass due to the volatilization of components in the glass can be suppressed. Accordingly, the Zr ⁴⁺ content is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less, and even more preferably 3.0% or less.
Zr ⁴⁺ may use _ZrO 2, ZrF _4, etc. as a raw material.

Ta ⁵⁺ is an optional component that can increase the refractive index of glass when it is contained in excess of 0%.
On the other hand, devitrification of glass can be reduced by making the content of Ta ⁵⁺ 10.0% or less. Accordingly, the Ta ⁵⁺ content is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less, and even more preferably 3.0% or less.
Ta ⁵⁺ can use Ta ₂ O ₅ or the like as a raw material.

Zn ²⁺ is an optional component that can enhance the devitrification resistance of the glass when it contains more than 0%.
On the other hand, when the Zn ²⁺ content is 30.0% or less, a decrease in refractive index can be suppressed. Therefore, the content of Zn ²⁺ is preferably 30.0% or less, more preferably 20.0%, still more preferably 10.0%, and still more preferably 5.0%.
As Zn ²⁺ , Zn (PO ₃ ) ₂ , ZnO, ZnF ₂ or the like can be used as a raw material.

Bi ³⁺ is an optional component that can increase the refractive index of the glass and lower the glass transition point when it contains more than 0%.
On the other hand, by making the Bi ³⁺ content 10.0% or less, devitrification of glass and reduction of visible light transmittance due to coloring can be suppressed. Accordingly, the Bi ³⁺ content is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less, and even more preferably 3.0% or less.
Bi ³⁺ can use Bi ₂ O ₃ or the like as a raw material.

Te ⁴⁺ is an optional component that can increase the refractive index of the glass and suppress coloring when it is contained in an amount of more than 0%.
On the other hand, by making the Te ⁴⁺ content 15.0% or less, devitrification of the glass and a decrease in visible light transmittance due to coloring can be suppressed. Therefore, the Te ⁴⁺ content is preferably 15.0% or less, more preferably 10.0% or less, still more preferably 8.0% or less, and even more preferably 5.0% or less.
Te ⁴⁺ can use TeO ₂ or the like as a raw material.

[About anion components]
The optical glass of the present invention contains O ²⁻ . The content of O ²⁻ is preferably 30.0% to 70.0%, for example.
In particular, by containing 30.0% or more of O ²⁻ , devitrification of glass and an increase in the degree of wear can be suppressed. Therefore, the content of O ²⁻ is preferably 30.0%, more preferably 40.0%, further preferably 45.0%, and further preferably 50.0%.
On the other hand, when the content of O ²⁻ is 70.0% or less, the effect of other anion components can be easily obtained. Therefore, the upper limit of the content of O ²⁻ is preferably 70.0%, more preferably 67.0%, still more preferably 65.0%, still more preferably 60.0%, and even more preferably 55.0%. And
O ²⁻ is an oxide of various cation components such as Al ₂ O ₃ , MgO and BaO, and a phosphate of various cation components such as Al (PO) ₃ , Mg (PO) ₂ and Ba (PO) ₂ as raw materials. Etc. can be used.

The optical glass of the present invention F ^- containing. The content of F ⁻ is preferably 30.0% to 70.0%, for example.
In particular, by containing 30.0% or more of F ⁻ , the anomalous dispersibility and Abbe number of the glass can be increased, and the devitrification resistance of the glass can be increased. Therefore, the content of F ⁻ is preferably 30.0%, more preferably 35.0%, further preferably 40.0%, and further preferably 42.5%.
On the other hand, the fall of the abrasion degree of glass can be suppressed by making content of F < ^- > 70.0% or less. Therefore, the content of F ⁻ is preferably 70.0%, more preferably 60.0%, further preferably 55.0%, and further preferably 50.0%.
Further, from the viewpoint of suppressing the devitrification of the glass, the total of the content of O ^{2− and} the content of F ⁻ is preferably 98.0%, more preferably 99.0%, and more preferably 100%. %.
F ⁻ can use fluorides of various cation components such as AlF ₃ , MgF ₂ , and BaF ₂ as raw materials.

[Other ingredients]
If necessary, other components can be added to the optical glass of the present invention as long as the properties of the glass of the present invention are not impaired.

[About ingredients that should not be contained]
Next, components that should not be contained in the optical glass of the present invention and components that are not preferably contained will be described.

  Other components not described above can be added as necessary within a range not impairing the properties of the glass of the present invention. However, the transition metal components such as Ce, V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo are colored by the glass even when contained in a small amount by combining them individually or in combination. In particular, optical glass that transmits wavelengths in the visible region is preferably substantially free of absorption because it has the property of attenuating the effect of increasing the visible light transmittance of the present invention by causing absorption at the wavelengths.

  Cb of Pb, Th, Cd, Tl, Os, Be, and Se have tended to refrain from being used as harmful chemical substances in recent years, leading to not only the glass manufacturing process but also the processing process and disposal after commercialization. Environmental measures are required. Therefore, when importance is placed on the environmental impact, it is preferable not to substantially contain them except for inevitable mixing. As a result, the optical glass is substantially free of substances that pollute the environment. Therefore, the optical glass can be manufactured, processed, and discarded without taking special environmental measures.

  Although cations such as Sb and Ce are useful as a defoaming agent, they tend to be excluded from optical glass in recent years as components that are disadvantageous to the environment. Therefore, it is preferable that the optical glass of the present invention does not contain Sb or Ce from such points.

[Production method]
The method for producing the optical glass of the present invention is not particularly limited. For example, the above raw materials are uniformly mixed so that each component is within a predetermined content range, and the prepared mixture is put into a quartz crucible, an alumina crucible or a platinum crucible and roughly melted, and then a platinum crucible, a platinum alloy Put in a crucible or iridium crucible and melt in the temperature range of 900 to 1250 ° C for 2 to 10 hours, stir to homogenize, blow out bubbles, etc., then lower the temperature to 900 ° C or lower and then stir to finish and stir It is possible to manufacture by removing the above, casting into a mold and slow cooling.

[Physical properties]
The optical glass of the present invention has a high refractive index. The optical glass of the present invention preferably has a high Abbe number (low dispersion).
In particular, the refractive index (nd) of the optical glass of the present invention is preferably 1.50, more preferably 1.51, and still more preferably 1.53. The upper limit of this refractive index is preferably 2.00, more preferably 1.90, and even more preferably 1.80.
The Abbe number (νd) of the optical glass of the present invention is preferably 70, more preferably 72, and still more preferably 74. The upper limit of this Abbe number may preferably be 90, more preferably 85, still more preferably 80.
By having such a high refractive index, a large amount of light can be obtained even if the optical element is thinned. In addition, by having such low dispersion, even with a single lens, focus shift (chromatic aberration) due to the wavelength of light is reduced. In addition, the refractive index and the Abbe number take such numerical values, so that when combined with optical glasses having optical properties of high refraction and high dispersion that have been announced in recent years, high-power optical design can be performed. Optical glass can be obtained.
Therefore, the optical glass of the present invention is useful in optical design, and the optical system can be made highly accurate and thin, so that the degree of freedom in optical design can be expanded.
The refractive index (nd) and Abbe number (νd) mean values obtained by measurement based on the Japan Optical Glass Industry Association Standard JOGIS01-2003.

  The optical glass of the present invention preferably has high devitrification resistance during glass production (in the specification, it may be simply referred to as “devitrification resistance”). Thereby, since the fall of the transmittance | permeability by crystallization of the glass at the time of glass preparation etc. is suppressed, this optical glass can be used preferably for the optical element which permeate | transmits visible lights, such as a lens. In addition, as a scale which shows that the devitrification resistance at the time of glass preparation is high, a liquidus temperature is low, for example.

The optical glass of the present invention preferably has a small specific gravity.
More specifically, the specific gravity of the optical glass of the present invention is 4.50 [g / cm ³ ] or less. Thereby, since the mass of an optical element and an optical apparatus using the same is reduced, it can contribute to the weight reduction of an optical apparatus. Therefore, the specific gravity of the optical glass of the present invention is preferably 4.50, more preferably 4.40, and preferably 4.30. The specific gravity of the optical glass of the present invention is generally about 3.00 or more, more specifically 3.50 or more, and more specifically 4.00 or more in many cases.
The specific gravity of the optical glass can be measured based on Japan Optical Glass Industry Association Standard JOGIS05-1975 “Measurement Method of Specific Gravity of Optical Glass”.

The optical glass of the present invention is preferably less colored.
In particular, when the optical glass of the present invention is represented by the transmittance of the glass, the wavelength (λ ₈₀ ) showing a spectral transmittance of 80% in a sample having a thickness of 10 mm is 450 nm or less, more preferably 400 nm or less, and still more preferably. Is 370,350 nm or less. In the optical glass of the present invention, a wavelength (λ ₅ ) showing a spectral transmittance of 5% in a sample having a thickness of 10 mm is 400 nm or less, more preferably 350 nm or less, and further preferably 330 300 nm or less. Thereby, the absorption edge of the glass is positioned in the ultraviolet region, and the transparency of the glass in the visible region is enhanced. Therefore, this optical glass can be used as a material for an optical element such as a lens.
The transmittance of the optical glass is measured according to Japan Optical Glass Industry Association Standard JOGIS02. More specifically, a face parallel polished product having a thickness of 10 ± 0.1 mm was measured for a spectral transmittance of 200 to 800 nm in accordance with JISZ8722, and λ ₈₀ (wavelength at 80% transmittance) and λ ₅ (transmittance). Wavelength at 5%).

[Preforms and optical elements]
A glass molded body can be produced from the produced optical glass by means of mold press molding such as reheat press molding or precision press molding. That is, a preform for mold press molding was prepared from optical glass, and after performing reheat press molding on this preform, polishing was performed to prepare a glass molded body, or polishing was performed. It is possible to produce a glass molded body by performing precision press molding on a preform, or a preform molded by a known floating molding or the like. In addition, the means for producing the glass molded body is not limited to these means.

  The glass molded body produced in this way is useful for various optical elements and optical designs. In particular, it is preferable to produce optical elements such as lenses, prisms, and mirrors from the optical glass of the present invention using means such as precision press molding. As a result, when used in optical equipment that transmits visible light to optical elements such as cameras and projectors, the optical system in these optical equipment is reduced in weight while realizing high-definition and high-precision imaging characteristics. Can be achieved.

Composition of glass of Examples (No. 1 to No. 11) and Comparative Example (No. 1) which are optical glasses of the present invention (indicated by mol% of cation% display or anion% display), refractive index (nd) Table 1 and Table 2 show the Abbe number (νd), the wavelengths (λ ₈₀ , λ ₅ ) and the specific gravity at which the spectral transmittances are 80% and 5%. The following examples are merely for illustrative purposes, and are not limited to these examples.

  The optical glasses of Examples and Comparative Examples are high-purity raw materials used in ordinary fluorophosphate glasses such as oxides, carbonates, nitrates, fluorides, and metaphosphate compounds corresponding to the raw materials of the respective components. After selecting and weighing to a composition ratio shown in the table and mixing uniformly, the mixture is put into a platinum crucible and is heated in an electric furnace at a temperature range of 900 to 1250 ° C. according to the degree of melting difficulty of the glass composition. After melting for 10 hours, homogenizing with stirring and blowing out bubbles, the temperature was lowered to 900 ° C. or lower, cast into a mold, and gradually cooled to prepare glass.

  The refractive indexes and Abbe numbers of the glasses of the examples and comparative examples were measured based on Japan Optical Glass Industry Association Standard JOGIS01-2003. In addition, as glass used for this measurement, what was processed with the annealing furnace on the annealing conditions of slow cooling fall rate -25 degrees C / hr was used.

Visible light transmittances of the glasses of Examples and Comparative Examples were measured according to Japan Optical Glass Industry Association Standard JOGIS02. In addition, in this invention, the presence or absence and the grade of coloring of glass were calculated | required by measuring the visible light transmittance | permeability of glass. Specifically, a face parallel polished product having a thickness of 10 ± 0.1 mm was measured for a spectral transmittance of 200 to 800 nm in accordance with JISZ8722, and λ ₅ (wavelength when the transmittance was 5%) and λ ₈₀ (transmittance). Wavelength at 80%).

  The specific gravity of the glass of an Example and a comparative example was measured based on Japan Optical Glass Industry Association standard JOGIS05-1975 "measurement method of specific gravity of optical glass".

As shown in Tables 1 and 2, the optical glass of each example had a refractive index of 1.50 or more, more specifically 1.53 or more, and was within a desired range. On the other hand, the glass of the comparative example had a refractive index of 1.49985 and was 1.50 or less. Therefore, it became clear that the optical glass of the Example of this invention has a high refractive index compared with the glass of a comparative example.
In addition, the optical glasses of the examples of the present invention all have an Abbe number of 70 or more, more specifically 74 or more, and this Abbe number is 90 or less, more specifically 80 or less. Met.

The optical glasses of the examples all had a specific gravity of 4.50 or less, more specifically 4.30 or less, and were within a desired range.

Therefore, it has been clarified that the optical glass of the example has a desired high refractive index while the Abbe number is in a desired range.

In addition, in all the optical glasses of the examples of the present invention, λ ₈₀ (wavelength at 80% transmittance) was 450 nm or less, more specifically 350 nm or less, and was in a desired range.
In addition, in all the optical glasses of the examples of the present invention, λ ₅ (wavelength at 5% transmittance) was 400 nm or less, more specifically 300 nm or less, and was in a desired range.

Although the present invention has been described in detail for the purpose of illustration, this embodiment is only for the purpose of illustration, and many modifications can be made by those skilled in the art without departing from the spirit and scope of the present invention. Will be understood.

Claims (11)

In cation% (mol%) display,
P5 ⁺ is 20.0-40.0%,
Al ³⁺ 15.0-40.0%,
Sr ²⁺ 5.0-30.0%,
Ba ²⁺ 25.0-31.0%,
1.6 to 4.1% Mg ²⁺
0 to 5% Ca ²⁺
The content of Gd ³⁺ is 0 to 8.0% and the content of Yb ³⁺ is 0 to 8.0%
Contains,
In terms of cation% (mol%), the ratio Ba ²⁺ / Mg ²⁺ of the Ba ²⁺ content and Mg ²⁺ content is 7.56 or more and 16.63 or less,
An optical glass containing O ²⁻ and F ^{2 −} as an anionic component, having a refractive index (nd) of 1.50 to 1.80 and an Abbe number (νd) of 70 to 80. The optical glass according to claim 1, wherein the total content of Li ⁺ + Na ⁺ + K ⁺ is 2.0% or less. 3. The total amount of Al ³⁺ and Ba ²⁺ content (cation%) Al ³⁺ + Ba ²⁺ expressed in cation% (mol%) is 40.0% or more and 60.0% or less. Optical glass. Total amount of P ⁵⁺ , Al ³⁺ and Ba ²⁺ content (cation%) P ⁵⁺ + Al ³⁺ + Ba ²⁺ is 60.0% or more and 90.0% or less in terms of cation% (mol%). The optical glass according to any one of claims 1 to 3. In terms of cation% (mol%), the ratio of Ba ²⁺ content and Al ³⁺ content ratio to Mg ²⁺ content (Ba ²⁺ + Al ³⁺ ) / Mg ²⁺ is 12.95 or more and 32.0 or less . The optical glass according to any one of claims 1 to 4. In cation% (mol%) display,
La ³⁺ content is 0 to 10.0%,
Y ³⁺ content is 0 to 10.0%, and
Lu ³⁺ content is 0 to 10.0%
The optical glass according to claim 1, which is contained. A total content (Ln ³⁺ : cation%) of La ³⁺ , Gd ³⁺ , Y ³⁺ , Yb ³⁺ and Lu ³⁺ in terms of cation% (mol%) is 20.0% or less. The optical glass according to any one of 1 to 6. Anion% (mol%) display,
O ²⁻ 50.0-70.0%
F ⁻ is 30.0 to 50.0%.
The optical glass according to claim 1, which is contained.   The optical glass according to any one of claims 1 to 8, having a specific gravity of 3.00 to 4.50.   An optical element made of the optical glass according to claim 1.   A preform for polishing and / or precision press molding comprising the optical glass according to claim 1.