TWI570088B - Optical glass, optical elements and preforms - Google Patents

Description

Optical glass, optical components and preforms

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

Lens systems for optical machines are typically designed by combining a plurality of glass lenses having different optical properties. In recent years, the characteristics required for the lens system of an optical device have been diversified, and in order to further expand the degree of freedom in design, an optical glass having an optical characteristic that has not been previously focused has been developed. Optical glass in which the abnormal dispersibility (Δθg, F) is characteristic has been attracting attention as a significant effect on color correction of aberrations.

For example, in Patent Literatures 1 to 4, an optical glass having a high degree of high refractive index, low dispersibility, and workability which is excellent in the prior art, and having high dispersibility is also known, for example, containing P ⁵⁺ and Al ^{3 . +} , an alkaline earth metal ion or the like as a cationic component, and an optical glass containing F ^- and O ^{2 -} as an anion component.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2007-55883

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2008-137877

[Patent Document 3] International Publication No. 2008/111439

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2009-256169

However, the prior optical glass processing as described in Patent Documents 1 to 4 Bad sex. That is, it is expected to develop an optical glass which maintains high abnormal dispersibility and has workability.

The object of the present invention is to solve the above problems.

That is, an object of the present invention is to provide an optical glass which can correct the chromatic aberration of a glass lens with high abnormal dispersibility and which is easier to polish than the former, and which is easy to be polished. And preforms.

The present inventors have made intensive studies to solve the above problems, and have completed the present invention.

The present invention is the following (1) to (8).

(1) An optical glass containing P ⁵⁺ , Al ^{3+ ,} and Mg ²⁺ as a cationic component, O ² and F ⁻ as an anion component, and Mg ²⁺ content (cation %) and Ca ²⁺ content The ratio of the total content (cation %) to the total content of alkaline earth metals (R ²⁺ : cation %) ((Mg ²⁺ + Ca ²⁺ ) / R ²⁺ ) is 0.25 or more, and the abrasion degree is 440 or less.

(2) The optical glass of the above (1), wherein the ratio of the Mg ²⁺ content (cation %) to the total content of the alkaline earth metal (R ²⁺ : cation %) (Mg ²⁺ /R ²⁺ ) is 0.30 or more.

(3) The optical glass according to (1) or (2) above, wherein the refractive index (nd) is 1.50 to 1.60, and the Abbe number ( v d) is 60 to 80.

(4) The optical glass according to any one of (1) to (3) above, wherein the partial dispersion ratio (θg, F) is 0.530 or more.

(5) The optical glass according to any one of (1) to (4) above, wherein the content of P ⁵⁺ is 20 to 55%, and the content of Al ³⁺ is expressed by % of cation (% by mole) 5 to 20%, the content of Mg ²⁺ is 0.1 to 30%, the content of Ca ²⁺ is 0.1 to 30%, the content of Sr ²⁺ is 0 to 20%, and the content of Ba ²⁺ is 0.1. ~ 25%, R ²⁺ content rate of 30 ~ 70%, Zn ²⁺ content ratio of 0 to 15% by anionic% (mole%) indicates the count, F ^- content rate of 20 to 70%.

(6) An optical element comprising the optical glass according to any one of (1) to (5) above.

(7) A preform comprising the optical glass according to any one of the above (1) to (5), which is used for polishing processing and/or precision press molding.

(8) An optical element obtained by precisely pressing a preform as in the above (7).

According to the present invention, it is possible to provide an optical glass, an optical element, and an optical glass which can be corrected by a high degree of abnormal dispersibility and which can correct the chromatic aberration of the glass lens with high degree of wear compared with the prior art. Shaped body.

The invention will be described.

The present invention relates to an optical glass comprising P ⁵⁺ , Al ³⁺ and Mg ²⁺ as a cationic component, O ² and F ⁻ as an anion component, Mg ²⁺ content (cation %) and Ca ²⁺ content. The ratio of the total content (R ²⁺ : cation %) of the alkaline earth metal ((Mg ²⁺ + Ca ²⁺ ) / R ²⁺ ) is 0.25 or more and the abrasion degree is 440 or less.

Hereinafter, such an optical glass is also referred to as "optical glass of the present invention".

<Glass composition>

The components constituting the optical glass of the present invention will be described.

In the present specification, the content of each component is all expressed by the cation % or the anion % based on the molar ratio, unless otherwise specified. Here, the "cation %" and the "anion %" are used to separate the glass constituent components of the optical glass of the present invention into a cationic component and an anionic component, and the total ratio thereof is set to 100 mol%, thereby indicating that the glass is in the glass. The composition of each component contained.

Further, for the sake of convenience, the ion valence of each component is a representative value, and is not distinguished from other ion valences. The ion valence of each component present in the optical glass may be other than the representative value. For example, P is usually present in the glass in a state in which the ionic value is 5, and thus is referred to as "P ⁵⁺ " in the present specification, but may exist in the state of other ion valence. Even if it is strictly in the state of other ion valence, in the present specification, each component is treated as an ion value of the representative value in the optical glass.

[About cationic ingredients] <P ⁵⁺ >

The optical glass of the present invention contains P ⁵⁺ . P ⁵⁺ is a glass forming component and has a property of suppressing devitrification of glass and increasing refractive index.

Since this property is enhanced, the content of P ⁵⁺ is preferably from 20.0 to 55.0%. Further, it is more preferably 25.0% or more, and still more preferably 30.0% or more. Further, it is more preferably 50.0% or less, still more preferably 45.0% or less, still more preferably 43.0% or less, still more preferably 41.0% or less.

P ⁵⁺ can be contained in the glass using, for example, Al(PO ₃ ) ₃ , Ca(PO ₃ ) ₂ , Ba(PO ₃ ) ₂ , Zn(PO ₃ ) ₂ , BPO ₄ , H ₃ PO ₄ or the like as a raw material.

<Al ³⁺ >

The optical glass of the present invention contains Al ³⁺ . Al ³⁺ has the property of improving the resistance to devitrification of the glass and reducing the abrasion.

Since this property is enhanced, the content of Al ³⁺ is preferably 5 to 20.0%. Further, it is more preferably 7.0% or more, still more preferably 10.0% or more, and still more preferably 12.0 or more. Further, it is more preferably 18.0% or less, further preferably 16.0% or less.

Al ³⁺ can be contained in the glass using, for example, Al(PO ₃ ) ₃ , AlF ₃ , Al ₂ O ₃ or the like as a raw material.

<alkaline earth metal>

In the optical glass of the present invention, the alkaline earth metal means Mg ²⁺ , Ca ²⁺ , Sr ^{2+ ,} and Ba ²⁺ . Further, at least one selected from the group consisting of Mg ²⁺ , Ca ²⁺ , Sr ^{2+ ,} and Ba ²⁺ may be represented as R ²⁺ .

In addition, the total content ratio of R ²⁺ refers to the total content ratio of these four kinds of ions (Mg ²⁺ + Ca ²⁺ + Sr ²⁺ + Ba ²⁺ ).

The total content of R ²⁺ is preferably from 30.0 to 70.0%. The reason for this is that if the content is in the above range, a more stable glass can be obtained.

The total content of R ²⁺ is more preferably 35.0% or more, still more preferably 40.0% or more, and still more preferably 44.0% or more. Further, it is more preferably 65.0% or less, still more preferably 60.0% or less, still more preferably 55.0% or less, still more preferably 53.0% or less.

<Mg ²⁺ >

The optical glass of the present invention contains Mg ²⁺ . Mg ²⁺ has the property of improving the resistance to devitrification of glass and reducing the degree of wear.

Since this property is enhanced, the content of Mg ²⁺ is preferably from 0.1 to 30.0%. Further, it is more preferably 2.0% or more, still more preferably 5.0% or more, still more preferably 10.0% or more. Further, it is more preferably 25.0% or less, further preferably 20.0% or less.

Mg ²⁺ can be contained in the glass using, for example, MgO, MgF ₂ or the like as a raw material.

<Ca ²⁺ >

The optical glass of the present invention preferably contains Ca ²⁺ . Ca ²⁺ has the property of improving resistance to devitrification, suppressing a decrease in refractive index, and reducing the abrasion of glass.

Since this property is enhanced, the content of Ca ²⁺ is more preferably from 0.1% to 30.0%. Further, it is more preferably 5.0% or more, still more preferably 10.0% or more, still more preferably 12.0% or more, and still more preferably 13.0% or more. Further, it is more preferably 20.0% or less, further preferably 16.0% or less.

Ca ²⁺ can be contained in the glass using, for example, Ca(PO ₃ ) ₂ , CaCO ₃ , CaF ₂ or the like as a raw material.

The optical glass of the present invention preferably contains Mg ²⁺ as an essential component and further contains Ca ²⁺ . When these two components are coexisted, the devitrification resistance of the glass, the decrease in the refractive index, and the reduction in the degree of wear are improved, and in particular, the property of improving the devitrification resistance of the glass is enhanced. Further, the optical glass of the present invention preferably further contains Sr ²⁺ and/or Ba ²⁺ as other alkaline earth metals.

In the optical glass of the present invention, the ratio of the total content of Mg ²⁺ (cation %) and Ca ²⁺ content (cation %) to the total content of alkaline earth metals (R ²⁺ : cation %) ((Mg) ²⁺ + Ca ²⁺ ) / R ²⁺ ) is 0.25 or more. The lower limit of (Mg ²⁺ + Ca ²⁺ ) / R ²⁺ is preferably 0.28, more preferably 0.31, still more preferably 0.34, still more preferably 0.36, still more preferably 0.38. Further, the upper limit of (Mg ²⁺ + Ca ²⁺ ) / R ²⁺ is preferably 0.80, more preferably 0.75, still more preferably 0.70, still more preferably 0.68.

The present inventors have found that an optical glass containing O ² and F ^- as an anion component, and further (Mg ²⁺ + Ca ^{2+ )} , is a cationic component containing P ⁵⁺ , Al ³⁺ , Mg ^{2+ ,} and Ca ²⁺ as a cationic component. When /R ²⁺ is 0.25 or more, an optical glass which can correct the chromatic aberration of the glass lens with high abnormal dispersibility and which has a lower degree of wear and is easier to be polished than the former is obtained. .

Further, in the optical glass of the present invention, the ratio of Mg ²⁺ content (cation %) (Mg ²⁺ /R ²⁺ ) is preferably 0.30 or more. The lower limit of Mg ²⁺ /R ²⁺ is preferably 0.32, more preferably 0.34, still more preferably 0.36, still more preferably 0.37. Further, the upper limit of Mg ²⁺ /R ²⁺ is preferably 0.75, more preferably 0.70, still more preferably 0.65, still more preferably 0.63.

The present inventors have found that an optical glass containing O ² and F ^- as an anion component, and (Mg ²⁺ + Ca ²⁺ )/R ² , is a cationic component containing P ⁵⁺ , Al ^{3+ ,} and Mg ²⁺ as a cationic component. ^{When +} is 0.25 or more, and Mg ²⁺ /R ²⁺ is 0.30 or more, it is possible to accurately correct the chromatic aberration of the glass lens by higher abnormal dispersibility, and further reduce the wear rate compared with the former. Optical glass that is easy to grind.

<Sr ²⁺ >

The optical glass of the present invention has a case where Sr ²⁺ is contained as one of R ²⁺ (alkaline earth metal). Sr ²⁺ has the property of improving the resistance to devitrification of the glass and suppressing the decrease in the refractive index.

Since this property is enhanced, the content of Sr ²⁺ is preferably from 0% to 20.0%. Further, it is more preferably 1.0% or more, further preferably 2.0% or more. Further, it is more preferably 17.0% or less, further preferably 14.0% or less.

Sr ²⁺ can be contained in the glass using, for example, Sr(NO ₃ ) ₂ , SrF ₂ or the like as a raw material.

<Ba ²⁺ >

The optical glass of the present invention may contain one type of Ba ²⁺ as R ²⁺ (alkaline earth metal). Ba ²⁺ has the property of improving the resistance to devitrification of glass when it contains a specific amount. Further, it has a property of maintaining low dispersibility and increasing the refractive index.

Since this property is enhanced, the content of Ba ²⁺ is preferably from 0.1 to 25.0%. Further, it is more preferably 20.0% or less, still more preferably 19.0% or less, still more preferably 17.0% or less. Further, it is preferably 1.0% or more, more preferably 5.0% or more, still more preferably 10.0% or more, still more preferably 12.0% or more, still more preferably 13.0% or more, still more preferably 14.0% or more.

Ba ²⁺ can be contained in the glass using, for example, Ba(PO ₃ ) ₂ , BaCO ₃ , Ba(NO ₃ ) ₂ , BaF ₂ or the like as a raw material.

<Zn ²⁺ >

The optical glass of the present invention may also contain Zn ²⁺ as an optional component. Zn ²⁺ has the property of improving the degree of wear and increasing the refractive index.

Since this property is enhanced, the content of Zn ²⁺ is preferably from 0% to 15.0%. Further, it is more preferably 1.0% or more, still more preferably 1.5% or more. Further, it is more preferably 12.0% or less, still more preferably 8.0% or less, still more preferably 4.0% or less, still more preferably 2.0% or less.

Zn ²⁺ can be contained in the glass using, for example, Zn(PO ₃ ) ₂ , ZnO, ZnF ₂ or the like as a raw material.

<Ln ³⁺ >

In the present invention, Ln ³⁺ means at least one selected from the group consisting of Y ³⁺ , La ³⁺ , Gd ³⁺ , Yb ³⁺ and Lu ³⁺ . In addition, the total content ratio of Ln ³⁺ means the total content rate of these five types of ions (Y ³⁺ + La ³⁺ + Gd ³⁺ + Yb ³⁺ + Lu ³⁺ ).

The optical glass of the present invention preferably contains Ln ³⁺ at a total content of 10.0% or less. The reason for this is that if the content is in the above range, the refractive index of the glass is increased and the dispersion tends to be low. Further, it is preferably 9.0% or less, more preferably 8.0% or less, still more preferably 7.0% or less. Further, since Ln ³⁺ is an optional component, the optical glass of the present invention may not contain Ln ³⁺ .

<Y ³⁺ >

The optical glass of the present invention may contain Y ³⁺ as one of Ln ³⁺ . Y ³⁺ has the property of maintaining low dispersibility, increasing refractive index, and improving resistance to devitrification. However, when the amount is excessive, the stability is likely to be deteriorated, so that it is more preferably 9.0% or less, more preferably 8.0% or less, still more preferably 7.0% or less. Further, since the Y ³⁺ free glass of the present invention can be obtained, so this viewpoint also free of Y ^3+.

Y ³⁺ can be contained in the glass using, for example, Y ₂ O ₃ , YF ₃ or the like as a raw material.

<La ³⁺ >

The optical glass of the present invention may contain La ³⁺ as one of Ln ³⁺ . La ³⁺ has the property of maintaining low dispersibility and increasing refractive index.

Since such a property is enhanced, the content of La ³⁺ is more preferably 9.0% or less, more preferably 8.0% or less, still more preferably 7.0% or less.

La ³⁺ can be contained in the glass using, for example, La ₂ O ₃ , LaF ₃ or the like as a raw material.

<Gd ³⁺ >

The optical glass of the present invention may contain Gd ³⁺ as one of Ln ³⁺ . Gd ³⁺ has the property of maintaining low dispersibility, increasing the refractive index, and further improving the resistance to devitrification.

Since such a property is enhanced, the content of Gd ³⁺ is more preferably 9.0% or less, more preferably 8.0% or less, still more preferably 7.0% or less.

Gd ³⁺ can be contained in the glass using, for example, Gd ₂ O ₃ , GdF ₃ or the like as a raw material.

<Yb ³⁺ >

The optical glass of the present invention may contain Yb ³⁺ as one of Ln ³⁺ . Yb ³⁺ has the property of maintaining low dispersibility, increasing the refractive index, and further improving the resistance to devitrification.

Since such a property is enhanced, the content of Yb ³⁺ is more preferably 9.0% or less, more preferably 8.0% or less, still more preferably 7.0% or less.

Yb ³⁺ can be contained in the glass using, for example, Yb ₂ O ₃ or the like as a raw material.

<Lu ³⁺ >

The optical glass of the present invention may contain Lu ³⁺ as one of Ln ³⁺ . Lu ³⁺ has the property of maintaining low dispersibility, increasing the refractive index, and further improving the resistance to devitrification.

Since such a property is enhanced, the content of Lu ³⁺ is more preferably 9.0% or less, still more preferably 8.0% or less, still more preferably 7.0% or less.

Lu ³⁺ can be contained in the glass using, for example, Lu ₂ O ₃ or the like as a raw material.

<Si ⁴⁺ >

The optical glass of the present invention may also contain Si ⁴⁺ as an optional component. When Si ⁴⁺ contains a specific amount, it has the property of improving the devitrification resistance of the glass, increasing the refractive index, and reducing the abrasion.

Since such a property is enhanced, the content of Si ⁴⁺ is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less.

Si ⁴⁺ can be contained in the glass using, for example, SiO ₂ , K ₂ SiF ₆ , Na ₂ SiF ₆ or the like as a raw material.

<B ³⁺ >

The optical glass of the present invention may also contain B ³⁺ as an optional component. When B ³⁺ contains a specific amount, it has a property of improving the devitrification resistance of the glass, increasing the refractive index, and reducing the degree of wear, thereby making it difficult to deteriorate the chemical durability.

Since such a property is enhanced, the content of B ³⁺ is preferably 15.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less, still more preferably 3.0% or less. Further, it is preferably 0.1% or more, more preferably 0.5% or more, still more preferably 1.0% or more.

B ³⁺ can be contained in the glass using, for example, H ₃ BO ₃ , Na ₂ B ₄ O ₇ , BPO ₄ or the like as a raw material.

<Li ⁺ >

The optical glass of the present invention may contain Li ⁺ as an optional component. Li ⁺ has the resistance to devitrification when the glass is formed, while reducing the properties of the glass transition point (Tg).

Since such a property is enhanced, the content of Li ⁺ is preferably 20.0% or less, more preferably 15.0% or less, still more preferably 10.0% or less.

Li ⁺ can be contained in the glass using, for example, Li ₂ CO ₃ , LiNO ₃ , LiF or the like as a raw material.

<Na ⁺ >

The optical glass of the present invention may also contain Na ⁺ as an optional component. Na ⁺ has resistance to devitrification when the glass is formed, while reducing the properties of the glass transition point (Tg).

Since such a property is enhanced, the content of Na ⁺ is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less.

Na ⁺ can be contained in the glass using, for example, Na ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ SiF ₆ or the like as a raw material.

<K ⁺ >

The optical glass of the present invention may also contain K ⁺ as an optional component. K ⁺ has the resistance to devitrification when the glass is formed, while reducing the properties of the glass transition point (Tg).

Since such a property is enhanced, the content of K ⁺ is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less.

K ⁺ can be contained in the glass using, for example, K ₂ CO ₃ , KNO ₃ , KF, KHF ₂ , K ₂ SiF ₆ or the like as a raw material.

<Rn ⁺ >

In the optical glass of the present invention, the total content of Rn ⁺ (Rn ⁺ is at least one selected from the group consisting of Li ⁺ , Na ⁺ and K ⁺ ) is preferably 20.0% or less, more preferably 15.0%. Hereinafter, it is more preferably 10.0% or less.

<Nb ⁵⁺ >

The optical glass of the present invention may also contain Nb ⁵⁺ as an optional component. Nb ⁵⁺ has the property of increasing the refractive index of the glass, improving the chemical durability, and further suppressing the decrease in the Abbe number.

Since such a property is enhanced, the content of Nb ⁵⁺ is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less.

Nb ⁵⁺ can be contained in the glass using, for example, Nb ₂ O ₅ or the like as a raw material.

<Ti ⁴⁺ >

The optical glass of the present invention may also contain Ti ⁴⁺ as an optional component. Ti ⁴⁺ has the property of increasing the refractive index of the glass.

Since such a property is enhanced, the content of Ti ⁴⁺ is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less.

Ti ⁴⁺ can be contained in the glass using, for example, TiO ₂ or the like as a raw material.

<Zr ⁴⁺ >

The optical glass of the present invention may also contain Zr ⁴⁺ as an optional component. Zr ⁴⁺ has the property of increasing the refractive index of the glass.

Since such a property is enhanced, the content of Zr ⁴⁺ is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less.

Zr ⁴⁺ can be contained in the glass using, for example, ZrO ₂ , ZrF ₄ or the like as a raw material.

<Ta ⁵⁺ >

The optical glass of the present invention may also contain Ta ⁵⁺ as an optional component. Ta ⁵⁺ has the property of increasing the refractive index of the glass.

Since such a property is enhanced, the content of Ta ⁵⁺ is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less.

Ta ⁵⁺ can be contained in the glass using, for example, Ta ₂ O ₅ or the like as a raw material.

<W ⁶⁺ >

The optical glass of the present invention may also contain W ⁶⁺ as an optional component. W ⁶⁺ has the property of increasing the refractive index of the glass and lowering the transfer point of the glass.

Since such a property is enhanced, the content of W ⁶⁺ is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less.

W ⁶⁺ can be contained in the glass using, for example, WO ₃ or the like as a raw material.

<Ge ⁴⁺ >

The optical glass of the present invention may also contain Ge ⁴⁺ as an optional component. Ge ⁴⁺ has the property of increasing the refractive index of glass and improving the resistance to devitrification of glass.

Since such a property is remarkable, the content of Ge ⁴⁺ is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less.

Ge ⁴⁺ can be contained in the glass using, for example, GeO ₂ or the like as a raw material.

<Bi ³⁺ >

The optical glass of the present invention may contain Bi ³⁺ as an optional component. Bi ³⁺ has the property of increasing the refractive index of the glass and lowering the transfer point of the glass.

Since such a property is enhanced, the content of Bi ³⁺ is preferably 10.0% or less, more preferably 8.0% or less, still more preferably 5.0% or less.

Bi ³⁺ can be contained in the glass using, for example, Bi ₂ O ₃ or the like as a raw material.

<Te ⁴⁺ >

The optical glass of the present invention may also contain Te ⁴⁺ as an optional component. Te ⁴⁺ has the property of increasing the refractive index of the glass, lowering the glass transition point, and suppressing coloration.

Since such a property is enhanced, the content of Te ⁴⁺ is preferably 15.0% or less, more preferably 10.0% or less, still more preferably 8.0% or less, still more preferably 5.0% or less.

Te ⁴⁺ can be contained in the glass using, for example, TeO ₂ or the like as a raw material.

[About anionic ingredients] <F ^- >

The optical glass of the present invention contains F ^- . F ^- has the property of increasing the abnormal dispersibility of the glass and the Abbe number, which makes the glass difficult to devitrify.

Since such a property is enhanced, the content of F ^- is preferably from 20.0 to 70.0% in terms of anion % (% by mole). Further, it is more preferably 30.0% or more, still more preferably 35.0% or more, and still more preferably 38.0% or more. Further, it is more preferably 60.0% or less, still more preferably 50.0% or less, still more preferably 48.0% or less.

F ^- can be contained in the glass using, for example, a fluoride of various cationic components such as AlF ₃ , MgF ₂ or BaF ₂ as a raw material.

<O ^2- >

The optical glass of the present invention contains O ^2- . O ^2- has a property of suppressing an increase in the abrasion of the glass.

Since such a property is enhanced, the content of O ^2- is preferably from 30.0 to 80.0% in terms of an anion % (% by mole). Further, it is more preferably 40.0% or more, still more preferably 45.0% or more, and still more preferably 50.0% or more. Further, it is more preferably 70.0% or less, more preferably 66.0% or less, still more preferably 62.0% or less.

Further, the total content of O ^{2- and} the content ratio of F ^- is preferably 98.0% or more, more preferably 99.0% or more, and still more preferably 100%, expressed as an anion %. The reason for this is that a stable glass can be obtained.

As the O ^{2 -} an oxide of various cationic components such as Al ₂ O ₃ , Mgo or BaO, or a phosphate of various cationic components such as Al(PO ₃ ) ₃ , Mg(PO ₃ ) ₂ or Ba(PO ₃ ) ₂ can be used. It is contained in the glass as a raw material.

In the optical glass of the present invention, other components may be added as needed within the scope of the characteristics of the glass of the invention of the present application.

[About ingredients that should not be included]

Next, the components which should not be contained in the optical glass of the present invention and the components which are not preferable in the description will be described.

The cations of transition metals such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo other than Ti, Zr, Nb, W, La, Gd, Y, Yb, and Lu have a small amount even if they are individually or in combination. In the case of the case, the glass is also colored, and the specific wavelength of the visible light region is absorbed. Therefore, in particular, in the optical glass using the wavelength of the visible light region, it is preferable that the optical glass is substantially not contained.

Further, cations of Pb, Th, Cd, Tl, Os, Be, and Se tend to be restricted as harmful chemical substances in recent years, and are not only used in the manufacturing steps of glass, but also in processing steps and post-product processing. All need to take measures against environmental measures. Therefore, when it is important to pay attention to the influence of the environment, it is preferable that the inclusion is not substantially contained except for the inevitable mixing. Thereby, the optical glass does not substantially contain a substance that pollutes the environment. Therefore, the optical glass can be manufactured, processed, and discarded without taking special measures for environmental measures.

Further, although Sb is used as an antifoaming agent, in recent years, it tends to be contained in an optical glass as a component which adversely affects the environment. From this viewpoint, Sb is preferably not contained.

Summary The above shows a preferred aspect of the optical glass of the present invention.

The optical glass of the present invention is preferably such that, as a cationic component, the content of P ⁵⁺ is 20 to 55% and the content of Al ³⁺ is 5 to 20%, expressed as % of cation (% by mole). The content of Mg ²⁺ is 0.1 to 30%, the content of Ca ²⁺ is 0.1 to 30%, the content of Sr ²⁺ is 0 to 20%, and the content of Ba ²⁺ is 0.1 to 25%, R ^{2 .} The content of ⁺ is 30 to 70%, the content of Zn ²⁺ is 0 to 15%, and the content of F ^- is 20 to 70%, and the content of O ^2- is expressed as % of anion (% by mole). The ratio is 30 to 80%, the refractive index (nd) is 1.50 to 1.60, the Abbe number ( v d) is 60 to 80, and the abrasion degree is 440 or less.

Further, it is preferred that the partial dispersion ratio (θg, F) is 0.530 or more.

[Production method]

The method for producing the optical glass of the present invention is not particularly limited. For example, the raw material can be uniformly mixed so that each component becomes within a specific content range, and the produced mixture is poured into quartz crucible or alumina crucible or platinum crucible for coarse melting, and then added. Platinum ruthenium, platinum alloy ruthenium or ruthenium is melted in the temperature range of 900~1200 °C for 2~10 hours, stirred and homogenized, defoamed, etc., and then cooled to a temperature below 850 °C, and then finely stirred to remove veins. Cast into the mold for slow cooling.

[physical property]

The optical glass of the present invention is characterized by a partial dispersion ratio (θg, F). Therefore, an optical glass in which chromatic aberration is corrected with high precision can be obtained.

The partial dispersion ratio (θg, F) is preferably 0.530 or more, more preferably 0.534 or more, still more preferably 0.538 or more.

Further, the partial dispersion ratio (θg, F) is a value obtained by measurement based on the Japan Optical Glass Industry Association standard JOGIS01-2003.

The optical glass of the present invention has a high degree of dispersibility (Δθg, F). Therefore, it is easy to obtain a lens which can correct chromatic aberration with high precision.

The abnormal dispersibility (Δθg, F) is preferably 0.010 or more, more preferably 0.012 or more, still more preferably 0.014 or more, still more preferably 0.016 or more, still more preferably 0.018 or more.

Here, the partial dispersion ratio (θg, F) and the abnormal dispersibility (Δθg, F) will be described, and then the characteristics of the physical properties of the optical glass of the present invention will be described in more detail.

First, the partial dispersion ratio (θg, F) will be described.

The partial dispersion ratio (θg, F) indicates the ratio of the refractive index difference in a certain two wavelength regions in the wavelength dependence of the refractive index, and is expressed by the following formula (1).

Θg, F=(n _g -n _F )/(n _F -n _C )...(1)

Here, n _g means the refractive index under g-ray (435.83 nm), n _F means the refractive index under F-ray (486.13 nm), and n _C means the refractive index under C-ray (656.27 nm).

Further, if the relationship between the partial dispersion ratio (θg, F) and the Abbe number ( v d) is plotted on the XY chart, in the case of a general optical glass, it is roughly plotted on a straight line called a regular line. on. The term "normal line" refers to the partial dispersion ratio of NSL7 and PBM2 on the XY graph (on the orthogonal coordinates) with the partial dispersion ratio (θg, F) as the vertical axis and the Abbe number ( v d) as the horizontal axis. And the line rising to the right at 2 o'clock formed by the Abbe number plot (see Fig. 1). Standard glass, which is the basis for the regular line, varies depending on the optical glass manufacturer, but each company is defined by roughly the same slope and intercept (NSL7 and PBM2 are optical glass manufactured by OHARA Co., Ltd., NSL7). The Abbe number ( v d) is 60.5, the partial dispersion ratio (θg, F) is 0.5436, the Abbe number ( v d) of PBM2 is 36.3, and the partial dispersion ratio (θg, F) is 0.5828).

With respect to the above partial dispersion ratio (θg, F), the so-called abnormal dispersion (Δθg, F) is a graph showing the partial dispersion ratio (θg, F) and the Abbe number ( v d) from the regular line to the vertical axis. The extent to which the direction deviates. An optical element comprising a glass having a high degree of dispersibility (Δθg, F) has a property of correcting chromatic aberration generated by other lenses in a wavelength range near blue.

Further, in the middle-low dispersion region (the region having an Abbe number of 55 or more), the higher the Abbe number ( v d), the higher the abnormal dispersibility (Δθg, F). Further, it is difficult to maintain the abnormal dispersibility at a high level while setting the abrasion degree to 440 or less.

The present inventors have actively studied and successfully developed an optical glass having an abnormal dispersibility (Δθg, F) with a high Abbe number ( v d) and good workability.

For example, in the case of the optical glass which is the preferred embodiment shown below, the partial dispersion ratio (θg) can be obtained when the abrasion degree is 405 or less and the Abbe number ( v d) is about 73 to 77. , F) is an optical glass having an abnormal dispersibility (Δθg, F) of 0.518 or more and 0.518 or more.

The optical glass of the present invention has a higher refractive index (nd) and a lower dispersibility (higher Abbe number).

In the optical glass of the present invention, the refractive index (nd) is preferably from 1.50 to 1.60, more preferably from 1.50 to 1.58. The refractive index (nd) is preferably 1.51 or more, more preferably 1.52 or more. Further, it is preferably 1.57 or less, more preferably 1.55 or less.

In the optical glass of the present invention, the Abbe number ( v d) is preferably from 60 to 80. The Abbe number is preferably 65 or more, more preferably 70 or more, and still more preferably 73 or more. Further, it is preferably 78 or less, more preferably 77 or less.

Further, the refractive index (nd) and the Abbe number ( v d) are values obtained by measurement based on the Japan Optical Glass Industry Association standard JOGIS01-2003.

The optical glass of the present invention preferably has an abrasion degree of at most 440 or less. Therefore, it is possible to reduce the wear and damage necessary for the optical glass, and it is easy to perform the polishing process in the optical glass, and the polishing process can be easily performed.

The degree of wear is more preferably 430 or less, more preferably 420 or less, still more preferably 410 or less, and still more preferably 405 or less.

On the other hand, if the abrasion degree is too low, it tends to be difficult to perform the polishing process. Therefore, the degree of abrasion is preferably 80 or more, more preferably 100 or more, still more preferably 120 or more.

In addition, the abrasion degree is a value obtained by measuring according to the "method of measuring the abrasion degree of optical glass of JOGIS10-1994".

Further, the optical glass of the present invention preferably has optical characteristics such as desired imaging characteristics in a wider temperature range.

In recent years, optical components assembled in optical devices such as projectors, photocopiers, laser printers, and playback devices have increased in use in more severe temperature environments. For example, in a projector, in order to meet the requirements of miniaturization and high resolution, it is necessary to use a high-intensity light source and a high-precision optical system. In particular, when a high-intensity light source is used, the temperature of the optical element constituting the optical system is liable to vary greatly due to the influence of the heat generated by the light source, and the temperature is more than 100 ° C. . In this case, if a high-precision optical system is used, the influence of temperature fluctuation on the imaging characteristics of the optical system and the like becomes large, and it is required to constitute an optical which does not cause variations in optical characteristics due to temperature fluctuation. system.

Further, even in an optical system that requires extremely high refractive index like an optical system of an optical device having high resolution, there is a case where the influence of the use temperature on the imaging characteristics or the like cannot be ignored.

The optical glass of the present invention is preferably an optical glass which can obtain optical characteristics such as desired imaging characteristics over a wider temperature range.

The optical glass of the present invention preferably has a relative refractive index temperature coefficient (dn/dT) close to zero. Specifically, the lower limit of the temperature coefficient (20 to 40 ° C) of the relative refractive index (589.29 nm) is preferably -6.0 × 10 ^-6 ° C ^-1 , more preferably -5.5 × 10 ^-6 ° C ^-1 , and thus Good for -5.0×10 ^-6 °C ^-1 . Thereby, even in an environment where the temperature of the optical element greatly changes, the variation of the refractive index is small, so that the desired optical characteristics can be exhibited with high precision in a wider temperature range.

On the other hand, if the temperature coefficient of the relative refractive index is excessively large in the positive direction, the change in the refractive index caused by the temperature change of the optical element is rather large. Therefore, the optical glass of the present invention can also set the upper limit of the temperature coefficient of the relative refractive index to more preferably 6.0 × 10 ^-6 ° C ^-1 , more preferably 5.5 × 10 ^-6 ° C ^-1 , still more preferably 5.0 × 10 ^-6 °C ^-1 . The optical glass of the present invention preferably has a temperature coefficient of relative refractive index of less than an absolute value, and is preferably 0.

Further, the temperature coefficient of the relative refractive index is expressed as the amount of change in the refractive index per 1 ° C when the temperature of the optical glass is changed while irradiating light having a wavelength of 589.29 nm in the same temperature as the optical glass. ×10 ^-6 °C ^-1 ).

[Preforms and optical components]

The optical glass of the present invention can be used for various optical elements and optical designs. Among them, it is particularly preferable to form a preform from the optical glass of the present invention, and to form a lens or a flaw or a reflection by using a method such as grinding or precision press forming on the preform. Optical components such as mirrors. Thereby, high-definition and high-precision imaging characteristics can be realized when used in an optical machine such as a camera or a projector that allows visible light to penetrate the optical element. Here, the method of manufacturing the preformed body material is not particularly limited, and a method of forming a glass gob as described in, for example, Japanese Patent Laid-Open No. Hei 8-319124, Japanese Patent Laid-Open No. Hei 8-73229 The method for producing the optical glass described above and the method for directly producing the preform material from the molten glass in the production apparatus may be a method of producing a cold-working such as grinding and polishing of the strip material formed of the optical glass.

Further, in the case of the optical glass of the present invention which can obtain optical characteristics such as desired imaging characteristics over a wider temperature range, it is preferable to use a more preferable preform and optical element.

[Examples]

The composition of the glass of Examples 1 to 16 and Comparative Example 1 of the optical glass of the present invention (expressed as % by mol or % of anion %), refractive index (nd), and Abbe number ( v d) The partial dispersion ratio (θg, F), the abnormal dispersibility (Δθg, F), and the abrasion degree (Aa) are shown in Table 1.

The optical glasses of Examples 1 to 16 and Comparative Example 1 of the present invention are each produced by selecting an oxide, a carbonate, a nitrate, a fluoride, a metaphosphoric acid compound or the like which are each a raw material of each component. The high-purity raw materials used in the fluorophosphate glass were weighed and uniformly mixed so as to have the composition ratios of the respective examples shown in Table 1, and then charged into a platinum crucible according to the melting difficulty of the glass composition in an electric furnace. It is melted at a temperature of 900 to 1200 ° C for 2 to 10 hours, stirred and homogenized, and defoamed to a temperature of 850 ° C or lower, and then cast into a mold to carry out slow cooling to produce glass.

Here, the refractive index (nd), the Abbe's number ( v d), and the partial dispersion ratio (θg, F) of the optical glasses of Examples 1 to 16 and Comparative Example 1 are based on the Japanese Optical Glass Industry Association standard JOGIS01-2003. Determination. Further, as the glass used in the measurement, the annealing condition was used to adjust the slow cooling rate to -25 ° C / hr, and the reactor was treated in a slow cooling furnace. Further, the difference between the value of the partial dispersion ratio (θg, F) on the normal line of FIG. 1 and the value of the measured partial dispersion ratio (θg, F) in the measured Abbe number ( v d) is obtained. Abnormal dispersion (Δθg, F).

Moreover, the degree of wear was measured based on "method of measuring the abrasion degree of optical glass of JOGIS10-1994". That is, a sample of a glass slab of 30 × 30 × 10 mm is placed in a cast iron flat disk (250 mm) rotated 60 times per minute in the horizontal direction. At a starting position 80 mm from the center, a load of 9.8 N (1 kgf) is applied vertically, and 20 mL of water is uniformly supplied to the water 20 mL for 5 minutes (average particle size is 20 μm) The polishing liquid obtained by grinding 10 g of the abrasive material (alumina A polishing grain) was rubbed, and the mass of the sample before and after the polishing was measured to determine the abrasion quality. Similarly, the wear quality of the standard sample specified by the Japan Optical Glass Industry Association was obtained.

The degree of wear = {(wear quality/specific gravity of the sample) / (wear quality / specific gravity of the standard sample)} × 100 was calculated.

In addition, the temperature coefficient (dn/dT) of the relative refractive index of the optical glass is the interference method in the method described in the Japanese Optical Glass Industry Association Standard JOGIS18-1994 "Method for Measuring the Temperature Coefficient of Refractive Index of Optical Glass". Determination.

As shown in Table 1, the refractive indices (nd) of the optical glasses of Examples 1 to 16 of the present invention were all 1.50 to 1.60, and the Abbe number ( v d) was 60 to 80.

Further, specifically, in any of the embodiments, the refractive index (nd) is 1.52 to 1.55, and the Abbe number ( v d) is 73 to 77. Further, in any of the examples, the degree of wear was 405 or less. Further, the partial dispersion ratio (θg, F) was 0.541 or more, and the abnormal dispersibility (Δθg, F) was 0.018 or more.

On the other hand, the optical glass of Comparative Example 1 other than the range of the present invention had a high degree of abrasion.

As shown in Table 1, the temperature coefficients (20 to 40 ° C) of the relative refractive indices of the optical glasses of Examples 1, 2, 6, 10, 11, 13, and 16 were -6.0 × 10 ^-6 ° C ^-1 or more. Within the required range.

Further, the optical glass of the embodiment of the present invention is used to form a preform for polishing, followed by grinding and polishing, and is processed into a shape of a lens and a crucible. Further, the optical glass of the embodiment of the present invention is used to form a preform for precision press molding, and the preform for precision press molding is subjected to precision press forming to be processed into a shape of a lens and a crucible. In either case, it can be processed into various lenses and shapes.

Fig. 1 is a view showing a regular line in which the partial dispersion ratio (θg, F) is the vertical axis and the Abbe number ( v d) is the orthogonal coordinate shown on the horizontal axis.

Claims (8)

An optical glass containing P ⁵⁺ , Al ³⁺ and Mg ²⁺ as a cationic component, containing O ²⁻ and F ⁻ as an anionic component, and containing B ³⁺ as a percentage of cation % (mol %) The ratio of the total content of Mg ²⁺ content (cation %) and Ca ²⁺ content (cation %) to the total content of alkaline earth metals (R ²⁺ : cation %) (% of Mg ^{2+ )} +Ca ²⁺ )/R ²⁺ ) is 0.25 or more and 0.8 or less, and the abrasion degree is 440 or less. The optical glass of claim 1, wherein the ratio of the Mg ²⁺ content (cation %) to the total content of the alkaline earth metal (R ²⁺ : cation %) (Mg ²⁺ /R ²⁺ ) is 0.30 or more and 0.75 the following. The optical glass of claim 1 or 2, wherein the refractive index (nd) is 1.50 to 1.60, and the Abbe number (νd) is 60 to 80. The optical glass of claim 1 or 2, wherein the partial dispersion ratio (θg, F) is 0.530 or more and 0.552 or less. The optical glass of claim 1 or 2, wherein the content of P ⁵⁺ is 20 to 55%, and the content of Al ³⁺ is 5 to 20%, expressed as cation % (% by mole), and Mg ²⁺ The content rate is 0.1 to 30%, the content of Ca ²⁺ is 0.1 to 30%, the content of Sr ²⁺ is 0 to 20%, the content of Ba ²⁺ is 0.1 to 25%, and the content of R ²⁺ . The content of Zn ²⁺ is 0 to 15%, and the content of F ^- is 20 to 70%, expressed as anion % (% by mole). An optical element comprising the optical glass of claim 1 or 2. A preform comprising the optical glass of claim 1 or 2 and which is used for grinding processing and/or precision press molding. An optical element obtained by precisely pressing a preform as claimed in claim 7.