TW201335100A - Optical glass, optical element, and preform - Google Patents

Abstract

The invention provids optical glass which has higher refractive index and high devitrification resistance, while having a desirably high Abbe number; and a preform and an optical element, each of which uses the optical glass. This optical glass contains P5+ and Al3+ as cation components, and the content of Al3+ is 25.0% or less in cation % based on the molar ratio. This optical glass contains O2- and F- as anion components, and has a refractive index (nd) of 1.53 or more. A preform for polishing and/or precision press molding and an optical element are formed of this optical glass.

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 devices are typically designed in combination with a plurality of glass lenses having different optical properties. In recent years, in order to further broaden the degree of freedom in designing a lens system of a variety of optical devices, an optical glass having optical characteristics not previously used has been used as an optical element such as a spherical surface and an aspherical lens. In particular, in optical design, the industry has developed a refractive index or a dispersion tendency depending on the purpose of reducing chromatic aberration of the entire optical system.

Among the optical glasses for producing optical elements, in particular, glass having a high refractive index (nd) and a high Abbe number (νd) which is lightweight and small in size can be used. As such a high refractive index low-dispersion glass, for example, an optical glass having a refractive index of 1.53 or more and having an Abbe number of 60 or more is known as a glass represented by Patent Document 1.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2007-055883

However, the height of the refractive index of the prior optical glass described in Patent Document 1 is insufficient. That is, it is expected to develop an optical glass having a higher Abbe number of 60 or more and a higher refractive index.

On the other hand, as a method of producing an optical element from optical glass, for example It is known that a method of obtaining a shape of an optical element by grinding and polishing a billet or a glass block formed of optical glass is obtained by reheating a billet or a glass block formed of optical glass to form (reheat press forming). A method of grinding and polishing a glass molded body, and a method of forming a shape of an optical element by molding a preform (a precision mold press molding) obtained from a blank or a glass block by an ultra-precision machined mold. Either method requires that a stable glass be obtained from the formation of a billet or glass block from the molten glass frit. Here, in the case where the stability (devitrification resistance) of the devitrification of the glass constituting the obtained green or glass block is lowered to cause crystallization in the inside of the glass, a glass which is preferable as an optical element has not been obtained.

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 having a desired higher Abbe number and a higher refractive index and higher devitrification resistance, and a preform and an optical element using the same.

The inventors of the present invention have made intensive studies to solve the above problems, and have completed the present invention. In particular, the invention provides the following.

(1) An optical glass containing P ⁵⁺ and Al ³⁺ as a cationic component, having a content of Al ³⁺ of 25.0% or less, containing O ² and F ^- as an anion component, and having a refractive index (nd) of 1.53 or more .

(2) The optical glass according to (1), which contains P ^{5 +} 10.0 to 70.0% in terms of cation % (% by mole).

(3) The optical glass according to (1) or (2), which further contains B ³⁺ 0.1 to 15.0% in terms of cation % (% by mole).

(4) The optical glass according to any one of (1) to (3), wherein the content of Mg ²⁺ is 0 to 20.0%, and the content of Ca ²⁺ is represented by % of cation (% by mole) 0~30.0%, the content of Sr ²⁺ is 0~30.0%, and the content of Ba ²⁺ is 0~50.0%.

(5) The optical glass according to (4), which contains Ba ²⁺ 20.0% or more in terms of cation % (% by mole).

(6) The optical glass according to any one of (1) to (5), wherein a total content (cation %) of P ⁵⁺ , B ³⁺ and Ba ²⁺ is from 30.0 to 80.0%.

The optical glass of any one of (1) to (6), wherein the total content (cation %) of P ⁵⁺ , B ³⁺ , Ba ²⁺ and Al ³⁺ is 95.0% or less.

(8) The optical glass according to any one of (1) to (7), wherein a total content (R ²⁺ : cation %) of the alkaline earth metal is 60.0% or less.

(9) The optical glass according to any one of (1) to (8), wherein the content of La ³⁺ is 0 to 10.0%, and the content of Gd ³⁺ is represented by % of cation (% by mole). 0 to 10.0%, the content of Y ³⁺ is 0 to 10.0%, the content of Yb ³⁺ is 0 to 20.0%, and the content of Lu ³⁺ is 0 to 10.0%.

(10) The optical glass of any one of (1) to (9), wherein a total content of La ³⁺ , Gd ³⁺ , Y ³⁺ , Yb ^{3+ ,} and Lu ³⁺ (Ln ³⁺ : cationic % ) is 20.0% or less.

(11) The optical glass according to any one of (1) to (10) above, wherein the content of Li ⁺ is 0 to 20.0%, and the content of Na ⁺ is 0, expressed as % of cation (% by mole). ~10.0%, the content of K ⁺ is 0~10.0%.

The optical glass of any one of (1) to (11), wherein the total content (Rn ⁺ : cation %) of the alkali metal is 20% or less.

(13) The optical glass according to any one of (1) to (12), wherein the content of Si ⁴⁺ is 0 to 10.0%, and the content of Zn ²⁺ is represented by % of cation (% by mole) 0~30.0%, the content of Nb ⁵⁺ is 0~10.0%, the content of Ti ⁴⁺ is 0~10.0%, the content of Zr ⁴⁺ is 0~10.0%, and the content of Ta ⁵⁺ is 0~ 10.0%, the content of W ⁶⁺ is 0 to 10.0%, the content of Ge ⁴⁺ is 0 to 10.0%, the content of Bi ³⁺ is 0 to 10.0%, and the content of Te ⁴⁺ is 0 to 15.0%. .

(14) (1) to (13) of the optical glass according to any, wherein the anionic% (mole%) indicates the count, F ^- content ratio of 20.0 ~ 70.0%, O ^2- content was of 30.0 ~80.0%.

(15) The optical glass according to any one of (1) to (14) which has 60 or more Abbe number (νd).

(16) The optical glass according to any one of (1) to (15), wherein the relationship between the refractive index (nd) and the Abbe number (νd) satisfies the relationship of nd ≧ - 0.00254 × νd + 1.760.

(17) An optical element comprising the optical glass of any one of (1) to (16).

(18) A preform for polishing processing and/or precision press molding, comprising the optical glass according to any one of (1) to (16).

(19) An optical member obtained by precisely pressing a preform such as (18).

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

The optical glass of the present invention contains P ⁵⁺ and Al ³⁺ as a cationic component, and has a content of Al ³⁺ of 25.0% or less, O ² and F ^- as an anion component, and a refractive index (nd) of 1.53 or more. By reducing the content of Al ³⁺ of the cationic component, the refractive index and Abbe number of the glass can be increased. Further, by comprising P ⁵⁺ as a cationic component, and containing F ^- as an anion component, the desired high Abbe number can be obtained, while improving the devitrification resistance of glass. Therefore, an optical glass having a desired higher Abbe number while having a higher refractive index and having higher devitrification resistance can be obtained.

Hereinafter, the optical glass of the present invention will be described. The present invention is not limited to the following aspects, and may be appropriately changed within the scope of the object of the present invention. And implementation. In addition, the description of the overlapping part is omitted, but the gist of the invention is not limited.

<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 expressed by the percentage of cation or anion % based on the molar ratio, unless otherwise specified. Here, "cation %" and "anion %" (hereinafter, referred to as "cation % (mole %)" and "anion % (mole %)") are the glass constituents of the optical glass of the present invention. The composition was divided into a cationic component and an anionic component, and the total ratio was set to 100 mol%, and the composition of each component contained in the glass was recorded.

Furthermore, the ion valence of each component uses only representative values for convenience, and thus 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 pentad. Therefore, in the present specification, P is represented as "P ⁵⁺ ", but it may exist in the state of other ion valence. As described above, strictly speaking, even if it exists in the state of another ion value, in this specification, each component is processed in the glass as the ion value of a representative value.

[About cationic ingredients]

Since P ⁵⁺ is a glass forming component, it should contain more than 0% as an essential component. In particular, by containing P ^{5 +} 10.0% or more, the devitrification resistance of the glass can be improved. Therefore, the content of P ⁵⁺ is preferably 10.0% as the lower limit, more preferably 20.0% as the lower limit, and still more preferably 30.0% as the lower limit.

On the other hand, by setting the content of P ⁵⁺ to 70.0%, the decrease in the refractive index or the Abbe number caused by P ⁵⁺ can be suppressed. Therefore, the content of P ⁵⁺ is preferably 70.0% as the upper limit, more preferably 60.0% as the upper limit, more preferably 50.0% as the upper limit, and still more preferably 45.0% as the upper limit.

P ⁵⁺ using _{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 as a raw material.

Al ³⁺ can improve the devitrification resistance by forming a skeleton which contributes to the fine structure of glass, and therefore should contain more than 0% as an essential component. Therefore, the content of Al ³⁺ is preferably a lower limit of more than 0%, more preferably 1.0% as a lower limit, still more preferably 5.0% as a lower limit, and still more preferably 10.0% as a lower limit.

On the other hand, by setting the content of Al ³⁺ to 25.0% or less, the decrease in the refractive index or the Abbe number caused by Al ³⁺ can be suppressed. Therefore, the upper limit of the content ratio of Al ³⁺ is preferably 25.0%, more preferably 22.0%, and further preferably 20.0%, and more preferably less than 17.0%.

As Al ^3+, Al(PO ₃ ) ₃ , AlF ₃ , Al ₂ O ₃ or the like can be used as a raw material.

B ³⁺ itself is a component for increasing the refractive index, and is an optional component which can improve the devitrification resistance when a Yb ³⁺ or Ba ²⁺ component which is a component which increases the refractive index is used. That is, when B ^{3+ is} contained in excess of 0%, the refractive index and devitrification resistance of the glass can be improved. Therefore, the content of B ³⁺ is preferably a lower limit of more than 0%, more preferably 0.1% as a lower limit, still more preferably 1.0% as a lower limit, and still more preferably 3.0% as a lower limit.

On the other hand, by setting the content ratio of B ³⁺ to 15.0% or less, deterioration of chemical durability can be suppressed. Therefore, the content of B ³⁺ is preferably 15.0% as an upper limit, more preferably 12.0% as an upper limit, and still more preferably 10.0% as an upper limit.

As B ^3+, H ₃ BO ₃ , Na ₂ B ₄ O ₇ , BPO ₄ or the like can be used as a raw material.

Mg ²⁺ is an optional component which can improve the devitrification resistance of glass when it contains more than 0%.

On the other hand, by setting the content of Mg ²⁺ to 20.0% or less, the decrease in the refractive index of the glass can be suppressed. Therefore, the content of Mg ²⁺ is preferably 20.0% as an upper limit, more preferably 10.0% as an upper limit, still more preferably 7.0% as an upper limit, and still more preferably 3.0% as an upper limit.

Mg ²⁺ can be used as a raw material using MgO, MgF ₂ or the like.

When Ca ²⁺ is contained in an amount of more than 0%, it is possible to increase the resistance to devitrification of the glass and to suppress the decrease in the refractive index. Therefore, the content of Ca ²⁺ is preferably set to be less than 0% as the lower limit, more preferably 1.0% as the lower limit, and still more preferably 2.0% as the lower limit.

On the other hand, by setting the content of Ca ²⁺ to 30.0% or less, it is possible to suppress the devitrification resistance or the decrease in the refractive index of the glass caused by the excessive content of Ca ²⁺ . Therefore, the content of Ca ²⁺ is preferably an upper limit of 30.0%, more preferably an upper limit of 20.0%, and still more preferably an upper limit of 10.0%.

Ca ²⁺ can be used as a raw material using Ca(PO ₃ ) ₂ , CaCO ₃ , CaF ₂ or the like.

Sr ²⁺ is an optional component which can improve the devitrification resistance of the glass and suppress the decrease in the refractive index when it is more than 0%.

On the other hand, when the content ratio of Sr ²⁺ is 30.0% or less, the devitrification resistance of the glass or the decrease in the refractive index due to the excessive content of Sr ²⁺ can be suppressed. Therefore, the content of Sr ²⁺ is preferably an upper limit of 30.0%, more preferably an upper limit of 20.0%, and still more preferably an upper limit of 10.0%.

Sr ²⁺ can use Sr(NO ₃ ) ₂ , SrF ₂ or the like as a raw material.

Ba ²⁺ is an optional component which can improve the devitrification resistance of the glass while maintaining a low dispersibility and can increase the refractive index when it exceeds 0%. Therefore, the content of Ba ²⁺ is preferably more than 0% as a lower limit, more preferably 10.0% as a lower limit, further preferably 20.0% as a lower limit, and further preferably 20.0% as a lower limit, and further preferably Jia can use 29.0% as the lower limit.

On the other hand, by setting the content of Ba ²⁺ to 50.0% or less, it is possible to suppress a decrease in the devitrification resistance of the glass due to the excessive content of Ba ²⁺ . Therefore, the content of Ba ²⁺ is preferably 50.0% as an upper limit, more preferably 40.0% as an upper limit, and more preferably 37.0% as an upper limit.

As Ba ^{2+ ,} Ba(PO ₃ ) ₂ , BaCO ₃ , Ba(NO ₃ ) ₂ , BaF ₂ or the like can be used as a raw material.

The total content of P ⁵⁺ , B ³⁺ and Ba ^{2+ in} the optical glass of the present invention is preferably 30.0% or more and 80.0% or less.

In particular, by reducing the total content rate to 30.0% or more, the devitrification resistance can be improved even if the content of Al ³⁺ is decreased. Therefore, the total content ratio (P ⁵⁺ + B ³⁺ + Ba ²⁺ ) is preferably 30.0% as the lower limit, more preferably 50.0% as the lower limit, still more preferably 55.0% as the lower limit, and further preferably The lower limit is 60.0%, and more preferably more than 65.0%.

On the other hand, when the total content ratio is 80.0% or less, the deterioration of the devitrification resistance due to the excessive content of the components can be suppressed. Therefore, the total content ratio (P ⁵⁺ + B ³⁺ + Ba ²⁺ ) is preferably 80.0% as an upper limit, more preferably 78.0% as an upper limit, and still more preferably 76.0% as an upper limit.

Moreover, the total content of P ⁵⁺ , B ³⁺ , Ba ²⁺ and Al ³⁺ of the optical glass of the present invention is preferably 95.0% or less. Thereby, the desired high refractive index is maintained while maintaining high resistance to devitrification. Therefore, the total content ratio (P ⁵⁺ + B ³⁺ + Ba ²⁺ + Al ³⁺ ) is preferably an upper limit of 95.0%, more preferably an upper limit of 93.0%, and still more preferably an upper limit of 91.0%.

On the other hand, by setting the total content ratio to 30.0% or more, the devitrification resistance can be improved by the components. Therefore, the total content ratio (P ⁵⁺ + B ³⁺ + Ba ²⁺ + Al ³⁺ ) is preferably 30.0% as the lower limit, more preferably 50.0% as the lower limit, and further preferably 70.0% as the lower limit. Further preferably, 80.0% may be used as the lower limit, and further preferably 85.0% may be used as the lower limit.

The alkaline earth metal refers to one or more selected from the group consisting of Mg ²⁺ , Ca ²⁺ , Sr ^{2+ ,} and Ba ²⁺ . Further, there is a case where one or more selected from the group consisting of Mg ²⁺ , Ca ²⁺ , Sr ^{2+ ,} and Ba ²⁺ is represented as R ²⁺ .

In addition, the total content ratio of R ²⁺ means a total content ratio of one or more of the four types of ions (for example, Mg ²⁺ + Ca ²⁺ + Sr ²⁺ + Ba ²⁺ ).

The total content of R ²⁺ is preferably 60.0% or less. Thereby, devitrification caused by excessive content of R ²⁺ can be reduced. Therefore, the total content of R ²⁺ is preferably 60.0% as the upper limit, more preferably 50.0% as the upper limit, more preferably 45.0% as the upper limit, and still more preferably 41.0% as the upper limit.

On the other hand, the total content ratio of R ²⁺ can be set to exceed 0%. Thereby, a glass having higher devitrification resistance can be obtained. Therefore, the total content of R ²⁺ is preferably more than 0% as the lower limit, more preferably 10.0% as the lower limit, still more preferably 20.0% as the lower limit, and still more preferably 30.0% as the lower limit.

La ³⁺ , Gd ³⁺ , Y ³⁺ , Yb ^{3+ ,} and Lu ³⁺ are arbitrarily capable of maintaining high refractive index and high Abbe number while at least one of them contains more than 0% while improving devitrification resistance. ingredient. In particular, since the devitrification resistance can be easily improved by containing La ^{3+ in} excess of 0%, the content of La ³⁺ is preferably more than 0% as a lower limit, more preferably 0.1% as a lower limit, and further preferably 0.5% may be used as the lower limit, and further preferably 1.0% may be used as the lower limit. Further, by containing Yb ^{3+ in} excess of 0%, the refractive index can be increased and the volatilization of F ^- or the like at the time of melting can be reduced. Therefore, the content of Yb ³⁺ is preferably more than 0% as a lower limit, more preferably 0.1. % is the lower limit, and further preferably 0.7% is the lower limit, and further preferably 2.0% is the lower limit.

On the other hand, by setting the respective contents of La ³⁺ , Gd ³⁺ , Y ³⁺ and Lu ³⁺ to 10.0% or less, and/or to set the content of Yb ³⁺ to 20.0% or less, it is possible to reduce Depletion caused by excessive content of the components. Therefore, the respective contents of La ³⁺ , Gd ³⁺ , Y ³⁺ and Lu ³⁺ are preferably 10.0% as an upper limit, more preferably 8.0% as an upper limit, and further preferably 5.0% as an upper limit, and further Jia is limited to 3.0%. Further, the content of Yb ³⁺ is preferably 20.0% as an upper limit, more preferably 15.0% as an upper limit, still more preferably 10.0% as an upper limit, and still more preferably 5.0% as an upper limit.

La ^{3O 3} , Gd ³⁺ , Y ³⁺ , Yb ^{3+ ,} and Lu ³⁺ may be La ₂ O ₃ , LaF ₃ , Gd ₂ O ₃ , GdF ₃ , Y ₂ O ₃ , YF ₃ , Yb ₂ O ₃ , Lu ₂ O ₃ or the like is used as a raw material.

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+ indicates} the total content ratio of these five kinds of ions (Y ³⁺ + La ³⁺ + Gd ³ + + Yb ³ + + Lu ³⁺ ).

In particular, by setting the total content of Ln ³⁺ to 20.0% or less, devitrification caused by excessive content of Ln ³⁺ can be reduced. Therefore, the total content of Ln ³⁺ is preferably 20.0% as an upper limit, more preferably 10.0% as an upper limit, and still more preferably 6.0% as an upper limit.

On the other hand, Ln ³⁺ may not be contained, but by containing Ln ^{3+ in} excess of 0%, high refractive index and high Abbe number can be maintained while devitrification resistance can be improved. Therefore, the total content of Ln ³⁺ is preferably 0.1% as the lower limit, more preferably 1.0% as the lower limit, and still more preferably 3.0% as the lower limit.

Li ⁺ , Na ⁺ and K ⁺ are optional components which can maintain high devitrification resistance when the glass is formed and which can lower the glass transition point when the content exceeds 0%. In particular, Li ⁺ has a strong effect of improving resistance to devitrification, and therefore the content of Li ⁺ is preferably more than 0% as a lower limit, more preferably 0.1% as a lower limit, and further preferably 0.3% as a lower limit.

On the other hand, when the content ratio of Li ⁺ is 20.0% or less, and/or the content ratio of one or more of Na ⁺ and K ⁺ is 10.0% or less, the decrease in refractive index or chemical durability can be suppressed. Deterioration. Therefore, the content of Li ⁺ is more preferably 20.0% as the upper limit, more preferably 10.0% as the upper limit, and still more preferably 5.0% as the upper limit. Further, the respective content ratios of Na ⁺ and K ⁺ are preferably 10.0% as an upper limit, more preferably 5.0% as an upper limit, and still more preferably 3.0% as an upper limit.

As Li ⁺ , Na ⁺ and K ^{+ ,} 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 may be used.} SiF ₆ or the like is used as a raw material.

In the present invention, Rn ⁺ means at least one selected from the group consisting of Li ⁺ , Na ⁺ and K ⁺ . In addition, the total content ratio of Rn ⁺ indicates the total content ratio (Li ⁺ +Na ⁺ +K ⁺ ) of the three kinds of ions.

In particular, by setting the total content of Rn ⁺ to 20.0% or less, it is possible to suppress a decrease in the refractive index of the glass or a deterioration in chemical durability. Therefore, the total content of Rn ⁺ is preferably 20.0% as an upper limit, more preferably 10.0% as an upper limit, and still more preferably 5.0% as an upper limit.

On the other hand, Rn ⁺ may not be contained, but the devitrification resistance may be improved by containing Rn ^{+ in} excess of 0%, and the glass transition point may be lowered. Therefore, the total content of Rn ⁺ is preferably at least 0% as a lower limit, more preferably 0.1% as a lower limit, and further preferably 0.3% as a lower limit.

Si ⁴⁺ is an optional component which can improve the devitrification resistance of the glass, increase the refractive index, and reduce the degree of wear when the content exceeds 0%.

On the other hand, by setting the content ratio of Si ⁴⁺ to 10.0% or less, devitrification caused by excessive content of Si ⁴⁺ can be reduced. Therefore, the content of Si ⁴⁺ is preferably an upper limit of 10.0%, more preferably an upper limit of 5.0%, and still more preferably an upper limit of 3.0%.

As Si ^4+, SiO ₂ , K ₂ SiF ₆ , Na ₂ SiF ₆ or the like can be used as a raw material.

Zn ²⁺ is an optional component which can improve the resistance to devitrification of glass when it contains more than 0%.

On the other hand, by setting the content of Zn ²⁺ to 30.0% or less, the decrease in the refractive index can be suppressed. Therefore, the content of Zn ²⁺ is preferably an upper limit of 30.0%, more preferably an upper limit of 15.0%, still more preferably an upper limit of 5.0%, and still more preferably an upper limit of 3.0%.

Zn ²⁺ can be used as a raw material using Zn(PO ₃ ) ₂ , ZnO, ZnF ₂ or the like.

Nb ⁵⁺ , Ti ⁴⁺ and W ⁶⁺ are arbitrary components which increase the refractive index of the glass when it contains more than 0%. Further, when Nb ^{5+ is} contained in an amount exceeding 0%, chemical durability can be improved. Further, when W ^{6+ is} more than 0%, the glass transition point can be lowered.

On the other hand, by setting the respective content ratios of Nb ⁵⁺ , Ti ⁴⁺ and W ⁶⁺ to 10.0% or less, it is possible to suppress the decrease in the Abbe number and suppress the visible light transmittance caused by the coloring of the glass. decline. Therefore, the respective content ratios of Nb ⁵⁺ , Ti ⁴⁺ and W ⁶⁺ are preferably 10.0% as an upper limit, more preferably 5.0% as an upper limit, and still more preferably 3.0% as an upper limit.

As Nb ⁵⁺ , Ti ⁴⁺ and W ^{6+ ,} Nb ₂ O ₅ , TiO ₂ , WO ₃ or the like can be used as a raw material.

Zr ⁴⁺ is an optional component which increases the refractive index of the glass when it contains more than 0%.

On the other hand, by setting the content ratio of Zr ⁴⁺ to 10.0% or less, it is possible to suppress streaking of the glass due to volatilization of the components in the glass. Therefore, the content of Zr ⁴⁺ is preferably an upper limit of 10.0%, more preferably an upper limit of 5.0%, and still more preferably an upper limit of 3.0%.

As Zr ^4+, ZrO ₂ , ZrF ₄ or the like can be used as a raw material.

Ta ⁵⁺ is an optional component which increases the refractive index of the glass when it contains more than 0%.

On the other hand, by setting the content ratio of Ta ⁵⁺ to 10.0% or less, the devitrification of the glass can be reduced. Therefore, the content of Ta ⁵⁺ is preferably an upper limit of 10.0%, more preferably an upper limit of 5.0%, and still more preferably an upper limit of 3.0%.

Ta ⁵⁺ can use Ta ₂ O ₅ or the like as a raw material.

Ge ⁴⁺ is an optional component which can increase the refractive index of the glass when it contains more than 0%, and can improve the devitrification resistance.

On the other hand, by setting the content of Ge ⁴⁺ to 10.0% or less, the material cost of the glass can be reduced by the decrease in the content of the expensive Ge ⁴⁺ . Therefore, the content of Ge ⁴⁺ is preferably set to 10.0%, more preferably 5.0%, and still more preferably 3.0%.

Ge ⁴⁺ can use GeO ₂ or the like as a raw material.

Bi ³⁺ and Te ⁴⁺ are arbitrary components which can increase the refractive index of the glass when the content exceeds 0% and can lower the glass transition point.

On the other hand, by setting the content of Bi ³⁺ to 10.0% or less, and/or setting the content of Te ⁴⁺ to 15.0% or less, it is possible to suppress visible light transmittance due to devitrification or coloration of glass. The decline. Therefore, the content of Bi ³⁺ is preferably an upper limit of 10.0%, more preferably an upper limit of 5.0%, and still more preferably an upper limit of 3.0%. Further, the content of Te ⁴⁺ is preferably an upper limit of 15.0%, more preferably an upper limit of 10.0%, and still more preferably an upper limit of 5.0%.

As Bi ²⁺ and Te ^4+, Bi ₂ O ₃ , TeO ₂ or the like can be used as a raw material.

[About anionic ingredients]

The optical glass of the present invention contains F ^- . The content ratio of F ^- is preferably, for example, 20.0% to 70.0%.

In particular, by containing F ^- 20.0% or more, the abnormal dispersibility or Abbe number of the glass can be improved, and the devitrification resistance of the glass can be improved. Thus, F ^- set the content ratio is preferably 20.0%, more preferably set to 23.0%, and further preferably set to 26.0%.

On the other hand, by setting the content ratio of F ^- to 70.0% or less, it is possible to suppress the deterioration of the degree of wear. Therefore, the content ratio of F ^- is preferably 70.0% as an upper limit, more preferably 60.0% as an upper limit, more preferably 50.0% as an upper limit, and still more preferably 40.0% as an upper limit.

F ^- A fluoride of various cationic components such as AlF ₃ , MgF ₂ or BaF ₂ can be used as a raw material.

The optical glass of the present invention contains O ^2- . The content of O ^2- is preferably, for example, 30.0% to 80.0%.

In particular, by containing O ^{2 -} 30.0% or more, the devitrification of the glass or the increase in the degree of abrasion can be suppressed. Therefore, the lower limit of the content ratio of O ^2- is preferably 30.0%, more preferably 40.0%, still more preferably 50.0%, and still more preferably 60.0%.

On the other hand, by setting the content of O ² to 80.0% or less, the effect of other anionic components can be easily obtained. Therefore, the upper limit of the content ratio of O ^2- is preferably 80.0%, more preferably 77.0%, and still more preferably 74.0%.

Further, from the viewpoint of suppressing devitrification of the glass, the total content of O ^{2 and} the content of F ^{- are} preferably 98.0% as a lower limit, more preferably 99.0% as a lower limit, and further preferably a lower limit. It is 100%.

Using O ^2- Al ₂ O _3, various cationic components of MgO, BaO or oxides such as _{Al (PO) 3, Mg (} PO) 2, Ba (PO) 2 , and other like phosphate as a raw material of the cationic component.

[About other ingredients]

In the optical glass of the present invention, other components may be added as needed within the range which does not impair the characteristics of the glass of the present invention.

[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 if they are contained will be described.

Regarding 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, respectively, individually or in combination In the case where a small amount is contained, the glass is also colored, and has a property of absorbing a specific wavelength in the visible light range, and therefore it is preferably substantially not contained in the optical glass which particularly uses a wavelength in the visible light range.

In recent years, cations of Pb, Th, Cd, Tl, Os, Be, and Se have been used as a harmful chemical substance, and not only the manufacturing steps of glass, but also the processing steps and the processing after productization require environmental countermeasures. Measures. Therefore, when it is important to pay attention to the influence of the environment, it is preferable that it is substantially not included in addition to the inevitable mixing. Thereby, the optical glass contains substantially no substances that pollute the environment. Therefore, the optical glass can be manufactured, processed, and discarded without taking special measures for environmental measures.

The cation of Sb or As can be used as a defoaming agent, but as a component which is disadvantageous to the environment, it has a tendency not to be contained in optical glass in recent years. Therefore, in this respect, the optical glass of the present invention is preferably free of Sb or As.

[Production method]

The method for producing the optical glass of the present invention is not particularly limited. For example, it can be produced by uniformly mixing the above-mentioned raw materials so that each component becomes within a specific content range, and putting the prepared mixture into quartz crucible or alumina crucible or platinum crucible for coarse melting, and then charging Into platinum rhodium, platinum alloy crucible or crucible, melt it at a temperature of 900~1200 °C for 2 to 10 hours, stir homogenize for defoaming, etc., then reduce to a temperature below 850 °C and then finally stir to remove Stripes are cast into the mold for slow cooling.

[physical property]

The optical glass of the present invention has a high refractive index. Further, 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 1.53 as a lower limit, more preferably 1.57 as a lower limit, further preferably 1.59 as a lower limit, and further preferably 1.60 as a lower limit, and further preferably. The lower limit is 1.607. The upper limit of the refractive index is preferably 2.00, more preferably 1.90, still more preferably 1.80.

Further, the Abbe number (νd) of the optical glass of the present invention is preferably 60 as a lower limit, more preferably 63 as a lower limit, still more preferably 66 as a lower limit, more preferably 90 as an upper limit, more preferably The upper limit is 85, and it is more preferable to use 80 as the upper limit.

Further, between the Abbe number (νd) and the refractive index (nd) of the optical glass of the present invention, it is preferable to satisfy the relationship of nd≧-0.00254×νd+1.760, and more preferably to satisfy nd≧-0.00254×νd+1.770. The relationship is best to satisfy the relationship of nd≧-0.00254×νd+1.790.

By having such a high refractive index, a large amount of light refraction can be obtained even if the optical element is made thinner. Moreover, by having such a low dispersion, even a single lens reduces the shift (chromatic aberration) of the focus caused by the wavelength of light. Further, by having such a relationship between the refractive index and the Abbe number, an optical glass capable of high-power optical design can be obtained when combined with an optical glass having high refractive index and high dispersion optical characteristics which has been published in recent years.

Therefore, the optical glass of the present invention is useful for optical design, and it is possible to increase the accuracy and size of the optical system, thereby broadening the degree of freedom in optical design.

Further, the refractive index (nd) and the Abbe number (νd) 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 a high resistance to devitrification when the glass is formed from a molten state. Thereby, the stability of the glass is improved and the crystallization is reduced, so that the optical characteristics of the optical element made of glass, in particular, the adverse effect on the transmittance can be reduced.

As an indicator of the resistance to devitrification, the de-dialysis starting temperature (Tx) described later can be used. The dialysis starting temperature (Tx) of the optical glass of the present invention is preferably 1200 ° C, more preferably 1100 ° C or less, further preferably 1000 ° C or less, and further preferably 950 ° C or less.

The optical glass of the present invention preferably has less volatilization of various components represented by the F component when the glass raw material is melted. Thereby, the generation of gases harmful to the environment is reduced, so that the working environment in the production of the optical glass can be more easily improved. More specifically, the amount of volatilization when the glass raw material is melted (the amount of volatilization when the raw material is melted) is preferably 3.00% or less, more preferably 2.50% or less, and further Good is 2.30% or less.

Here, the amount of volatilization of each component can be measured, for example, by the following method.

Specifically, about 200 mg of the blended glass raw material was weighed and placed in a DTA (differential thermal analysis) crucible made of alumina, and heated to 1,100 ° C at a temperature increase rate of 40 ° C / min for 30 minutes. The time of holding for 30 minutes was taken as the starting point, and further maintained at 1100 ° C for 60 minutes. The amount of mass change after the start point and 60 minutes from the start point was defined as the amount of volatilization, and the amount thereof was determined.

Further, the amount of volatilization of each component can also be evaluated by the following method.

That is, 100 cm ³ of the glass raw material was sufficiently melted in a capped 300 cc platinum crucible at 1000 to 1200 ° C, and the obtained melt was taken out together with the melting vessel to the outside of the furnace, and visually confirmed that the lid was opened immediately after opening the lid. The amount of white smoke. In this case, the case where the white smoke is small is evaluated as "(very good) or "○ is good", and the case where the white smoke is large is evaluated as "poor" or "very bad". Here, the case where the white smoke is small is particularly small, and the case where the white smoke is particularly small is evaluated as "very good", and the case where the white smoke is particularly large is evaluated as "very bad".

[Preforms and optical components]

The optical glass of the present invention is useful 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 molding on the preform. Optical components such as mirrors. Thereby, high precision and high can be achieved when used for an optical device such as a camera or a projector that allows visible light to penetrate the optical element. Imaging characteristics of precision. In particular, since the optical glass of the present invention has a small variation in refractive index due to temperature change, it is possible to realize high-definition and high-precision imaging characteristics even in applications such as high temperature for use as a projector. Here, the method of producing the preform is not particularly limited, and for example, a method of forming a glass blank described in Japanese Patent Laid-Open No. Hei 8-319124, or an optical glass as described in Japanese Patent Laid-Open No. Hei 8-73229 A method of directly producing a preformed body from molten glass like the method and the manufacturing apparatus. Further, a method of performing cold working such as grinding and polishing on a strip formed of optical glass may be used.

[Examples]

The composition of the glass of the optical glass of the present invention (No. 1 to No. 38) and the comparative example (No. A) (indicated by the cation % or the % of the anion %), and the refractive index (nd) The Abbe's number (νd) and the degree of volatilization during melting of the raw materials (only referred to as "degree of volatilization" in the table) are shown in Tables 1 to 5. Further, the volatilization amount and the devitrification resistance at the time of melting the raw materials of the glass of the examples and the comparative examples are shown in Table 6. Furthermore, the following embodiments are for illustrative purposes and are not limited to the embodiments.

The optical glass of the examples and the comparative examples of the present invention are each used as a raw material of each component, and the respective fluorophosphate glasses such as oxides, carbonates, nitrates, fluorides, and metaphosphoric compounds are used. The purity raw materials were weighed and uniformly mixed in such a manner as to have a composition ratio of the respective examples shown in Tables 1 to 5, and then introduced into a platinum crucible, and the electric furnace was used at 900 to 1200 ° C according to the melting difficulty of the glass composition. The temperature range is melted for 2 to 10 hours, and the mixture is homogenized for defoaming, etc., and the temperature is lowered to After casting at 850 ° C or lower, it is cast into a mold and slowly cooled to prepare a glass.

Here, the refractive indices and Abbe numbers of the optical glasses of the examples and the comparative examples were measured based on the Japan Optical Glass Industry Association standard JOGIS01-2003. Then, for the obtained refractive index and the value of the Abbe number, the intercept b in the relation nd ≧ 0.00 - 0.00254 × νd + b is obtained (the intercept b is expressed as "nd + 0.00254 * νd" in the table) . Further, as the glass used in the measurement, the annealing condition was such that the slow cooling rate was set to -25 ° C / hr, and the treatment was carried out in a slow cooling furnace.

Further, regarding the degree of volatilization during melting of the glass raw materials of the examples and the comparative examples, a glass material of 100 cm ³ was placed on the lid at 1000 to 1200 ° C, and a lid containing platinum or a refractory, a platinum having an inner diameter of 85 mm and a height of 65 mm was used. After fully melting in 坩埚 (300 cc), the obtained melt was taken out of the furnace together with the melting vessel, and a black plate of 30 cm × 30 cm was placed on the back of the crucible, and the amount of white smoke immediately after opening the lid was visually confirmed. . At this time, the center line of the horizontal direction of the black plate is arranged so as to coincide with the center line of the horizontal direction of the cymbal.

In this case, the case where the white smoke is small is evaluated as "(very good) or "○ is good", and the case where the white smoke is large is evaluated as "poor" or "very bad". Here, the case where the white smoke is small is particularly small, and the case where the white smoke is particularly small is evaluated as "very good", and the case where the white smoke is particularly large is evaluated as "very bad".

Further, the volatility at the time of melting the raw materials of the glasses of the examples and the comparative examples was also measured by the following method.

Weigh about 200 mg of blended glass material and put it into DTA made of alumina. In the crucible, it was heated to 1100 ° C at a heating rate of 40 ° C / min for 30 minutes. The time of holding for 30 minutes was taken as the starting point, and further maintained at 1,100 ° C for 60 minutes. The amount of mass change after the start point and 60 minutes from the start point was defined as the amount of volatilization, and the amount thereof was determined.

Further, regarding the devitrification resistance of the glass of the examples and the comparative examples, the obtained glass was pulverized to a particle size of 425 to 600 μm, and about 200 mg of the pulverized glass sample was weighed and placed in a DTA crucible made of alumina. The heating rate was heated to 950 ° C at a rate of 10 ° C / min. After the heating temperature reached 950 ° C, the temperature was cooled to 600 ° C at a cooling rate of 5 ° C / min, and the highest heat generation onset temperature Tx (-5) of the differential heat curve detected at this time was measured. Further, similarly, after the heating temperature reached 950 ° C, the temperature was cooled to 600 ° C at a temperature drop rate of 2.5 ° C / min, and the highest heat generation onset temperature Tx (-2.5) of the differential heat curve detected at this time was measured. The temperature at which the self-measured Tx(-5) and Tx(-2.5) were extrapolated to the temperature drop rate of 0 °C/min was defined as the dedialysis start temperature (Tx), and the temperature was determined.

As shown in Tables 1 to 6, the optical glass of the examples of the present invention has a refractive index of 1.53 or more, and more specifically 1.59 or more, which is within a desired range. On the other hand, the refractive index of Comparative Example (No. A) was less than 1.53. Therefore, it is clear that the optical glass of the embodiment of the present invention has a higher refractive index than the glass of the comparative example.

Further, the optical glass of the embodiment of the present invention has an Abbe number of 60 or more, more specifically 65 or more, and the Abbe number is 80 or less, and more specifically 70 or less, which is within a desired range.

Further, between the optical glass Abbe number (νd) and the refractive index (nd) of the embodiment of the present invention, the relationship of nd ≧ - 0.00254 × νd + 1.760 is satisfied, and more specifically, nd ≧ - 0.00254 × νd + 1.767 is satisfied. The relationship is within the required range.

Further, the "degree of volatilization" in the optical glass watch of the embodiment of the present invention is "?" or "○", and it is clear that the generation of white smoke at the time of melting is small. Moreover, the amount of volatilization of the optical glass of the embodiment of the present invention is 3.00% or less, more specifically The statement is 2.15% or less. On the other hand, the glass volatile amount of the comparative example of the present invention was 3.15%. Therefore, it is presumed that the optical glass of the present invention has less volatilization of each component represented by the F component at the time of melting than the glass of the comparative example.

Further, the optical glass has an dialysis starting temperature of 1200 ° C or less, more specifically 940 ° C or less, which is within a desired range.

Therefore, it is clear that the optical glass Abbe number of the embodiment of the present invention is within the desired range, while the refractive index and the devitrification resistance are high, and the volatilization of the components at the time of melting is less.

Further, a glass block is formed using the optical glass of the embodiment of the present invention, and the glass block is ground and polished to be processed into a shape of a lens and a crucible. As a result, it can be stably processed into various lenses and shapes of the crucible.

The present invention has been described in detail above for the purpose of illustration, and the embodiments of the present invention are to be construed as illustrative only.

Claims (19)

An optical glass containing P ⁵⁺ and Al ³⁺ as a cationic component, and having an Al ³⁺ content of 25.0%, containing O ²⁻ and F ⁻ as an anion component, and having a refractive index (nd) of 1.53 or more. The optical glass of claim 1, wherein P ^{5 +} 10.0 to 70.0% is expressed as % of cation (% by mole). The optical glass of claim 1, wherein the optical % (mol%) is further represented by B ³⁺ 0.1 to 15.0%. The optical glass of claim 1, wherein the content of Mg ²⁺ is 0 to 20.0%, the content of Ca ²⁺ is 0 to 30.0%, and the content of Sr ²⁺ is expressed by % of cation (% by mole). It is 0~30.0%, and the content of Ba ²⁺ is 0~50.0%. The optical glass of claim 4, which contains Ba ²⁺ 20.0% or more in terms of cationic % (% by mole). The optical glass of claim 1, wherein the total content (cation %) of P ⁵⁺ , B ³⁺ and Ba ²⁺ is from 30.0 to 80.0%. The optical glass of claim 1, wherein the total content (% of cations) of P ⁵⁺ , B ³⁺ , Ba ²⁺ and Al ³⁺ is 95.0%. The optical glass of claim 1, wherein the total content of the alkaline earth metals (R ²⁺ : cation %) is 60.0% or less. The optical glass of claim 1, wherein the content of La ³⁺ is 0 to 10.0%, the content of Gd ³⁺ is 0 to 10.0%, and the content of Y ³⁺ is expressed by % of cation (% by mole). The content of Yb ³⁺ is 0 to 20.0%, and the content of Lu ³⁺ is 0 to 10.0%. The optical glass of claim 1, wherein a total content ratio (Ln ³⁺ : cationic %) of La ³⁺ , Gd ³⁺ , Y ³⁺ , Yb ³⁺ and Lu ³⁺ is 20.0% or less. The optical glass of claim 1, wherein the content of Li ⁺ is 0 to 20.0%, the content of Na ⁺ is 0 to 10.0%, and the content of K ⁺ is 0 by the percentage of cation % (% by mole). 10.0%. The optical glass of claim 1, wherein the total content of alkali metals (Rn ⁺ : cationic %) is 20% or less. The optical glass of claim 1, wherein the content of Si ⁴⁺ is 0 to 10.0%, the content of Zn ²⁺ is 0 to 30.0%, and the content of Nb ⁵⁺ is expressed by % of cation (% by mole). 0 to 10.0%, the content of Ti ⁴⁺ is 0 to 10.0%, the content of Zr ⁴⁺ is 0 to 10.0%, the content of Ta ⁵⁺ is 0 to 10.0%, and the content of W ⁶⁺ is 0. ~10.0%, the content of Ge ⁴⁺ is 0 to 10.0%, the content of Bi ³⁺ is 0 to 10.0%, and the content of Te ⁴⁺ is 0 to 15.0%. The optical glass of claim 1, wherein the content of F ^- is 20.0 to 70.0%, and the content of O ² is 30.0 to 80.0%, expressed as an anion % (% by mole). The optical glass of claim 1, which has an Abbe number (νd) of 60 or more. The optical glass of claim 1, wherein the relationship between the refractive index (nd) and the Abbe number (νd) satisfies the relationship of nd ≧ - 0.00254 × νd + 1.760. An optical element comprising the optical glass of any one of claims 1 to 16. A preform for grinding processing and/or precision press forming, comprising the optical glass according to any one of claims 1 to 16. An optical component obtained by precisely pressing a preform as claimed in claim 18.