TW201702203A - Optical glass, optical element and the preform - Google Patents

Abstract

The present invention provides an optical glass, a preform using the same, and an optical element, wherein the optical glass contains the necessarily higher refractive index and Abbe number and at the same time reduces the fracture and cracking of the glass during pressurized molding to thereby further enhance the productivity of the optical element. The optical glass of the present invention contains P5+ and Al3+ to be used as the cationic ingredient and contains O2- and F- to be used as the anionic ingredient, whose refractive index (nd) is above 1.5, and the maximum value ([alpha] max) of the linear expansion coefficient within the temperature range between the glass transition temperature (Tg) and the deformation point (At) is below 1500 x 10-7K-1.

Description

Optical glass, optical components and preforms

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

In recent years, the use of optical systems has been rapidly increasing in the direction of digitization or high-definition, and the accuracy and weight reduction of optical components such as lenses used in various optical devices such as digital cameras and video cameras. The requirements are gradually increasing.

In particular, since the method of manufacturing an aspherical lens by grinding or grinding is costly and inefficient, as a method of manufacturing an aspherical lens, a glass paste ball or a glass brick is cut and ground. The material is softened by heating, and is formed by press molding using a molding die having a high-precision surface, thereby eliminating the grinding and grinding steps, thereby achieving low-cost, mass production.

The demand for a glass having a higher refractive index (nd) and a higher Abbe number (νd), which is particularly thinner or lighter in optical components, is used as the optical glass for such press forming. Very high. For such a high refractive index low dispersion glass, for example, as an optical glass having a refractive index of 1.50 or more, glass represented by Patent Documents 1 to 5 is known.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2008-137877

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2009-256149

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2010-235429

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2012-001422

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2012-012282

However, in the optical glass described in Patent Documents 1 to 5, a large amount of cracking or cracking of the glass occurs during press forming. Here, glass which is broken or cracked after press forming cannot be used as an optical element. Therefore, it is expected to develop an optical glass which can reduce breakage or cracking during press forming.

The present invention has been made in view of the above problems, and an object thereof is to provide an optical glass, a preform and an optical element using the same, which have a desired higher refractive index and Abbe number on one side, and can be reduced on one side. The breakage or cracking of the glass during press forming can further improve the productivity of the optical element.

The inventors of the present invention have diligently studied in order to solve the above problems, and have completed the present invention. Specifically, the present invention provides the following.

(1) An optical glass containing P ⁵⁺ and Al ³⁺ as a cationic component and containing O ² and F ^- as an anion component, and having a refractive index (nd) of 1.50 or more at a glass transition point (Tg) and deformation The maximum value (α _max ) of the linear expansion coefficient in the temperature range between points (At) is 1500 × 10 ^-7 K ^-1 or less.

(2) The optical glass according to (1), which contains P ⁵⁺ 20.0 to 55.0%, Al ³⁺ 5.0 to 30.0%, and Ca ²⁺ content of 0 to 30.0% in terms of cation % (% by mole).

(3) The optical glass of (1), wherein the content of Sr ²⁺ is 0 to 25.0%, expressed as % of cation (% by mole).

(4) The optical glass of (1), which further contains Ca ²⁺ and Sr ²⁺ as a cation component.

(5) The optical glass of (1), which has a cation % (mol%), and contains P ⁵⁺ 20.0 to 55.0%, Al ³⁺ 5.0 to 30.0%, Ca ²⁺ 0.1 to 30.0%, and Sr ²⁺ 0.1. ~25.0%.

(6) The optical glass of (1), wherein the total amount of the P ⁵⁺ content and the Al ³⁺ content (cation %) is 30.0% or more and 65.0% or less.

(7) The optical glass according to (1), wherein the content of Ba ²⁺ is 45.0% or less, expressed as % of cation (% by mole).

(8) The optical glass of (1), wherein the ratio of Ca ²⁺ content to Sr ²⁺ content (Ca ²⁺ /Sr ²⁺ ) is 0.50 or more, expressed as cation % (% by mole).

(9) (1) of an optical glass, wherein the content of Ca ²⁺ and Ba ²⁺ ratio at a total amount of (cationic%) of 10.0% and 60.0% or less.

(10) (1) of an optical glass, wherein the cationic% (mole%) represents, Mg ²⁺ containing ratio of 30.0% or less.

(11) The optical glass according to (1), wherein the ratio of Mg ²⁺ content to Sr ²⁺ content (Mg ²⁺ /Sr ²⁺ ) is 5.00 or less, expressed as % of cation (% by mole).

(12) The optical glass of (1), wherein the total content of the alkaline earth metals (R ²⁺ : cation %) is 30.0 to 70.0%.

(13) The optical glass according to (1), wherein the content of Li ⁺ is 10.0% or less in terms of cationic % (% by mole).

(14) The optical glass of (1), wherein the content of La ³⁺ is 0 to 10.0%, and the content of Gd ³⁺ is 0 to 10.0%, and Y ³⁺ is represented by % of cation (% by mole). The content rate is 0 to 10.0%, and the content of Yb ³⁺ is 0 to 10.0%.

(15) The optical glass of (1), wherein a total content ratio (Ln ³⁺ : cationic %) of La ³⁺ , Gd ³⁺ , Y ³⁺ and Yb ³⁺ is 0 to 20.0%.

(16) The optical glass according to (1), wherein the content of Na ⁺ is 0 to 10.0%, and the content of K ⁺ is 0 to 10.0%, expressed as % of cation (% by mole).

(17) The optical glass of (1), wherein the total content (Rn ⁺ : cationic %) of the alkali metal is 20.0% or less.

(18) The optical glass of (1), wherein the content of Si ⁴⁺ is 0 to 10.0%, and the content of B ³⁺ is 0 to 15.0%, and Zn ²⁺ is represented by % of cation (% by mole). The content rate is 0~30.0%, the content of Ti ⁴⁺ is 0~10.0%, the content of Nb ⁵⁺ is 0~10.0%, the content of W ⁶⁺ is 0~10.0%, and the content of Zr ⁴⁺ 0 to 10.0%, the content of Ta ⁵⁺ 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. ~15.0%.

(19) (1) of an optical glass, wherein the anionic% (mole%) represents, F ^- content ratio of 20.0 ~ 70.0%, O ^2- content ratio of 30.0 to 80.0%.

(20) The optical glass of (1), which has an Abbe number (νd) of 60 or more.

(21) An optical element comprising the optical glass according to any one of (1) to (20).

(22) A preform for polishing processing and/or precision press molding, comprising the optical glass according to any one of (1) to (20).

(23) An optical element obtained by precisely pressurizing a preform such as (22).

According to the present invention, it is possible to provide an optical glass, a preform and an optical element using the same, which have a desired higher refractive index and Abbe number on one side, and can prevent the glass after press forming from being easily produced. Broken or cracked, which in turn increases the health of the optical components Productivity.

The optical glass of the present invention contains P ⁵⁺ and Al ³⁺ as a cationic component, and contains O ² and F ⁻ as an anion component, and has a refractive index (nd) of 1.50 or more at a glass transition point (Tg) and a deformation point (At The maximum value (α _max ) of the linear expansion coefficient in the temperature range between them is 1500 × 10 ^-7 K ^-1 or less. The first optical glass of the present invention satisfies the requirements.

Further, the second optical glass of the present invention contains P ⁵⁺ , Al ³⁺ , Ca ^{2+ ,} and Sr ²⁺ as a cationic component, and contains O ²⁻ and F ⁻ as an anion component, and has a refractive index (nd) of 1.50 or more. The maximum value (α _max ) of the linear expansion coefficient in the temperature range between the glass transition point (Tg) and the deformation point (At) is 1500 × 10 ^-7 K ^-1 or less.

In the optical glass of the present invention, since the content of the other components is combined in the constitution of the first and second optical glasses, a desired higher refractive index and Abbe number can be obtained, and even if heated to a temperature higher than the glass transition point The temperature is subjected to press forming, and the glass after press forming is also less likely to be broken, and cracks are less likely to occur. Therefore, since the optical element can be made thinner or lighter, and in particular, the glass which is broken or cracked in the step of press forming the glass in the manufacturing step of the optical element can be reduced, the production of the optical element can be improved. Sex.

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 modified and implemented within the scope of the object of the present invention. In addition, the description of the repeated description is omitted, but the present 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 ratio of each component is expressed in terms of a molar ratio and a cationic % or an anionic %, particularly in the case where it is not described beforehand. Here, "cation %" And "anion %" (hereinafter sometimes referred to as "cation % (mole %)" and "anion % (mole %)") are the glass components of the optical glass of the present invention separated into cationic components and The anion component, and the total ratio of each is set to 100 mol%, and represents the composition of the content rate of each component contained in glass.

Furthermore, since the ion valence of each component is only a representative value for the sake of convenience, it is not distinguished from other ion valences. The ion valence of each component present in the optical glass has a possibility other than the representative value. For example, since P is usually present in the glass at a valence of 5 valence, P is expressed as "P ⁵⁺ " in the present specification, but may exist in the state of other ion valence. Thus, strictly speaking, even in the state of other ion valences, in the present specification, each component is also considered to exist in the glass at the ion value of the 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⁺ 20.0% or more, the devitrification resistance of the glass can be improved. Therefore, the content of P ⁵⁺ is preferably 20.0%, more preferably 25.0%, and still more preferably 28.0%.

On the other hand, by setting the content of P ⁵⁺ to 55.0% or less, the maximum value of the linear expansion coefficient of the glass can be lowered, and the decrease in the refractive index or the Abbe number due to P ⁵⁺ can be suppressed. Therefore, the content of P ⁵⁺ is preferably 55.0%, more preferably 50.0%, still more preferably 45.0%, still more preferably 42.0%, still more preferably 39.0%, and still more preferably 37.0%. . In particular, in the second optical glass, the upper limit of the content ratio of P ⁵⁺ may be set to 36.0%.

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⁺ is a component which contributes to the formation of a fine structure of glass by containing more than 0%, thereby improving the devitrification resistance. Therefore, the content of Al ³⁺ is preferably more than 0%, more preferably 5.0%, still more preferably 6.0%, still more preferably 8.0%, and still more preferably 10.0%. In particular, in the second optical glass, the lower limit of the content ratio of Al ³⁺ may be set to 11.0%.

On the other hand, by setting the content of Al ³⁺ to 30.0% or less, the maximum value of the linear expansion coefficient of the glass can be lowered, and the decrease in the refractive index or the Abbe number due to Al ³⁺ can be suppressed. Therefore, the content of Al ³⁺ is preferably 30.0%, more preferably 28.0%, still more preferably 25.0%, still more preferably 20.0%, and still more preferably 16.0%.

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

When the Ca ²⁺ system contains more than 0%, the maximum value of the linear expansion coefficient of the glass can be reduced, and the composition of the glass which is resistant to devitrification can be improved. In particular, in the second optical glass, Ca ²⁺ is contained as an essential component. Therefore, the content of Ca ²⁺ is preferably more than 0%, more preferably 0.1%, still more preferably 5.5%, still more preferably 10.0%, and still more preferably 12.0%.

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⁺ . Thus, Ca ²⁺ content ratio of preferably 30.0%, more preferably 25.0% to 23.0% and further preferably the upper limit. In particular, in the second optical glass, the upper limit of the content of Ca ²⁺ may be 21.0%.

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

The optical glass of the present invention preferably has a total content of P ⁵⁺ and Al ³ of 30.0% or more and 65.0% or less.

In particular, by setting the total content ratio to 30.0% or more, the devitrification resistance of the glass can be improved. Therefore, the total content ratio (P ⁵⁺ + Al ³⁺ ) is preferably 30.0%, more preferably 35.0%, still more preferably 40.0%, and still more preferably 43.0%.

On the other hand, by setting the total content ratio to 65.0% or less, the maximum value of the linear expansion coefficient of the glass can be lowered. Therefore, the total content ratio (P ⁵⁺ + Al ³⁺ ) is preferably 65.0%, more preferably 60.0%, still more preferably 55.0%, and still more preferably 52.0%. In particular, in the second optical glass, the upper limit of the total content ratio (P ⁵⁺ + Al ³⁺ ) may be 51.0%.

When the Sr ²⁺ is contained in an amount exceeding 0%, the maximum value of the linear expansion coefficient of the glass can be lowered, the devitrification resistance of the glass can be improved, and the composition of the refractive index can be suppressed. In particular, in the second optical glass, Sr ²⁺ is contained as an essential component. Therefore, in particular, in the second optical glass, the content of Sr ²⁺ is preferably more than 0%, more preferably 0.1%, still more preferably 3.0%, and still more preferably 4.5%.

On the other hand, by setting the content ratio of Sr ²⁺ to 25.0% or less, stable glass can be obtained even if the content of Ca ^{2+ which} is particularly strong to lower the maximum coefficient of linear expansion of the glass is further increased. Further, it is possible to suppress the devitrification resistance or the decrease in the refractive index of the glass caused by the excessive content of Sr ²⁺ . Therefore, the content of Sr ²⁺ is preferably 25.0%, more preferably 20.0%, still more preferably 18.0%, still more preferably 15.0%, still more preferably 13.0%, and still more preferably 10.0%. .

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

When the Ba ²⁺ system contains more than 0%, the devitrification resistance of the glass can be improved, and the maximum coefficient of linear expansion of the glass can be lowered, the dispersion can be maintained, and the refractive index can be increased. . Therefore, the content of Ba ²⁺ is preferably more than 0%, more preferably 3.0%, still more preferably 6.5%, still more preferably 9.0%, and still more preferably 12.0%. In particular, in the second optical glass, the lower limit of the content ratio of Ba ²⁺ may be set to 14.0%.

On the other hand, by setting the content of Ba ²⁺ to 45.0% or less, it is possible to suppress a decrease in the devitrification resistance of the glass caused by the excessive content of Ba ²⁺ . Therefore, the content of Ba ²⁺ is preferably 45.0%, more preferably 40.0%, still more preferably 35.0%, and still more preferably 32.0%.

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.

In the optical glass of the present invention, the ratio of the Ca ²⁺ content to the Sr ²⁺ content is preferably 0.50 or more. Thereby, the desired high refractive index can be obtained by Sr ²⁺ , and the linear expansion of the glass can be further reduced by lowering the maximum value of the linear expansion coefficient than the Ca ^{2+ of} Sr ²⁺ or Ba ²⁺ . The maximum value of the coefficient. Therefore, the cation ratio (Ca ²⁺ /Sr ²⁺ ) is preferably 0.50, more preferably 0.70, still more preferably 0.90, and still more preferably 1.10 as a lower limit. In particular, in the first optical glass, the lower limit of the cation ratio (Ca ²⁺ /Sr ²⁺ ) may be set to 1.50.

Furthermore, the upper limit of the cation ratio (Ca ²⁺ /Sr ²⁺ ) may also be infinite (ie, the Sr ²⁺ content is 0%), for example, 10.00, more specifically 8.00, and more specifically Can be 5.00 as the upper limit. In particular, in the second optical glass, the upper limit of the cation ratio (Ca ²⁺ /Sr ²⁺ ) may be 4.30.

The optical glass of the present invention preferably has a total content of Ca ²⁺ and Ba ²⁺ of 10.0% or more and 60.0% or less.

In particular, by setting the total content ratio to 10.0% or more, the maximum value of the linear expansion coefficient of the glass can be further reduced. Therefore, the total content ratio (Ca ²⁺ +Ba ²⁺ ) is preferably 10.0%, more preferably 16.0%, still more preferably 20.0%, still more preferably 25.0%, still more preferably 27.0%, and further preferably The lower limit is 30.0%.

On the other hand, by setting the total content ratio to 60.0% or less, it is possible to suppress a decrease in the devitrification resistance caused by the excessive content of the components. Thus, the total content (Ca ²⁺ + Ba ²⁺⁾ is preferably 60.0%, more preferably 55.0%, and further preferably from 50.0% to 48.0% and further preferably the upper limit.

When the content of Mg ²⁺ is more than 0%, the maximum value of the coefficient of linear expansion of the glass can be lowered, and any component which is resistant to devitrification of the glass can be improved.

However, among the Mg ²⁺ alkaline earth metals, the weakest component which lowers the maximum value of the linear expansion coefficient of the glass is used. Thus, by the Mg ²⁺ content ratio of 30.0% or less, increasing the maximum amount of addition of other alkaline earth metals and stability of the glass can be formed, and therefore can be more easily reduced maximum value of the coefficient of linear expansion of the glass. Moreover, the decrease in the refractive index of the glass can be suppressed. Therefore, the content of Mg ²⁺ is preferably 30.0%, more preferably 25.0%, still more preferably 22.0%, still more preferably 21.0%, and still more preferably 19.0%. In particular, in the second optical glass, the content of Mg ²⁺ is more preferably 15.0%, more preferably less than 10.0%, and still more preferably 7.5%.

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

In particular, in the second optical glass, the ratio of the Mg ²⁺ content to the Sr ²⁺ content is preferably 5.00 or less. Accordingly, since the relative effect of reducing the maximum value of the reduction coefficient of linear expansion of Sr ²⁺ and stronger than the effect of a strong increase in refractive index of the content of Mg ^2+, and therefore can be easily obtained a high refractive index and coefficient of linear expansion The smaller the optical glass. Therefore, particularly in the second optical glass, the cation ratio (Mg ²⁺ /Sr ²⁺ ) is preferably 5.00, more preferably 4.10, still more preferably 2.80, still more preferably 1.60, still more preferably 1.00, and further Preferably, 0.87 is also an upper 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, one or more 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⁺ is a total content ratio of one or more of the four kinds of ions (for example, Mg ²⁺ + Ca ²⁺ + Sr ²⁺ + Ba ²⁺ ).

The total content of R ²⁺ is preferably 30.0% or more and 70.0% or less. In particular, by containing R ²⁺ 30.0% or more, the maximum value of the linear expansion coefficient of the glass can be lowered, and a glass having higher devitrification resistance can be obtained. Therefore, the total content of R ²⁺ is preferably 30.0%, more preferably 38.0%, still more preferably 45.0%, and still more preferably 48.0%. In particular, in the second optical glass, the lower limit of the total content of R ²⁺ may be 50.0%.

On the other hand, by setting the content of R ²⁺ to 70.0% or less, devitrification caused by excessive content of R ²⁺ can be reduced. Therefore, the total content of R ²⁺ is preferably 70.0%, more preferably 65.0%, still more preferably 60.0%, and still more preferably 58.0%. In particular, in the second optical glass, the upper limit of the total content of R ²⁺ may be 57.0%.

When Li ⁺ is contained in an amount exceeding 0%, the devitrification resistance at the time of formation of a high glass can be maintained, and the arbitrary component of a glass transition point can be reduced.

On the other hand, by setting the Li ⁺ content to 10.0% or less, stable glass can be obtained even if more Ca ^{2+ is} added, so that the maximum value of the linear expansion coefficient of the glass can be more easily lowered. Further, it is possible to suppress a decrease in the refractive index or a deterioration in chemical durability. Therefore, the content of Li ⁺ is more preferably 10.0%, more preferably 5.0%, more preferably less than 2.0%, still more preferably less than 1.5%.

Li ⁺ can use Li ₂ CO ₃ , LiNO ₃ , LiF or the like as a raw material.

La ³⁺ , Gd ³⁺ , Y ^{3+ ,} and Yb ³⁺ can maintain a high refractive index and a high Abbe number when at least one of them contains more than 0%, and can improve any component that is resistant to devitrification. .

On the other hand, by setting the content of each of La ³⁺ , Gd ³⁺ , Y ³⁺ and Yb ³⁺ to 10.0% or less, devitrification caused by excessive content of the components can be reduced, and the glass can be lowered. Material cost. ^{Thus, La 3+, Gd 3+, Y} 3+ and Lu ³⁺ of the respective content is preferably 10.0%, more preferably 5.0% to 3.0% and further preferably the upper limit.

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

Ln ³⁺ means one or more selected from the group consisting of Y ³⁺ , La ³⁺ , Gd ^{3+ ,} and Yb ³ . Further, the total content ratio of Ln ³⁺ may indicate the total content ratio of these five kinds of ions (Y ³⁺ + La ³⁺ + Gd ³⁺ + Yb 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, and the material cost of the glass can be reduced. Therefore, the total content of Ln ³⁺ is preferably 20.0%, more preferably 10.0%, still more preferably 5.0%, still more preferably 2.0%, and still more preferably 0.8%.

When Na ⁺ and K ⁺ are contained in an amount exceeding 0%, the devitrification resistance at the time of formation of a high glass can be maintained, and the arbitrary component of a glass transition point can be reduced.

On the other hand, when the content ratio of one or more of Na ⁺ and K ⁺ is 10.0% or less, the decrease in the refractive index or the deterioration in chemical durability can be suppressed. Therefore, the content of each of Na ⁺ and K ⁺ is preferably 10.0%, more preferably 5.0%, and still more preferably 3.0%.

As Na ² and K ^{+ ,} Na ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ SiF ₆ , K ₂ CO ₃ , KNO ₃ , KF, KHF ₂ , K ₂ SiF ₆ or the like can be used as a raw material.

In the present invention, Rn ⁺ means one or more selected from the group consisting of Li ⁺ , Na ⁺ and K ⁺ . In addition, the total content ratio of Rn ⁺ may indicate the total content ratio (Li ⁺ +Na ⁺ +K ⁺ ) of the three types 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%, more preferably 10.0%, and still more preferably 5.0%.

When Si ⁴⁺ is contained in an amount of more than 0%, the devitrification resistance of the glass can be improved, and the refractive index can be increased, and the wear resistance can be reduced.

On the other hand, by setting the content 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 10.0%, more preferably 5.0%, and still more preferably 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.

When B ³⁺ is contained in an amount exceeding 0%, it can increase the refractive index of the glass and any component which is resistant to devitrification.

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%, more preferably 10.0%, and still more preferably 5.0%.

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.

When the Zn ²⁺ system contains more than 0%, it can increase any component of the glass which is resistant to devitrification.

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 30.0%, more preferably 20.0%, still more preferably 10.0%, and still more preferably 5.0%.

Using Zn ²⁺ _{Zn (PO 3) 2, ZnO} , ZnF 2 , etc. as a raw material.

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

On the other hand, by setting the content ratio of each 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. The decline. Therefore, the content of each of Nb ⁵⁺ , Ti ⁴⁺ and W ⁶⁺ is preferably 10.0%, more preferably 5.0%, and still more preferably 3.0%.

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 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 caused by volatilization of the components in the glass. Therefore, the content of Zr ⁴⁺ is preferably 10.0%, more preferably 5.0%, and still more preferably 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 glass when it contains more than 0%.

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

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

When the Ge ⁴⁺ is contained in an amount exceeding 0%, the refractive index of the glass can be increased, and any component which is resistant to devitrification can be improved.

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

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

When Bi ³⁺ and Te ⁴⁺ are contained in an amount exceeding 0%, the refractive index of the glass can be increased, and any component of the glass transition point can be lowered.

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 devitrification of the glass or visible light penetration by coloring. The rate has dropped. Accordingly, Bi ³⁺ content ratio of preferably 10.0%, more preferably 5.0% to 3.0% and further preferably the upper limit. Further, the content of Te ⁴⁺ is preferably 15.0%, more preferably 10.0%, and still more preferably 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 set to, for example, 20.0% to 70.0%.

In particular, by containing F ^- 20.0% or more, the abnormal dispersion property or the Abbe number of the glass can be improved, and the devitrification resistance of the glass can be improved. Therefore, the content of F ^- is preferably 20.0%, more preferably 25.0%, still more preferably 30.0%, still more preferably 36.0%.

On the other hand, by setting the content ratio of F ^- to 70.0% or less, it is possible to suppress a decrease in the abrasion rate of the glass. Therefore, the content of F ^- is preferably 70.0%, more preferably 60.0%, still more preferably 55.0%, and still more preferably 51.0%.

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 ratio of O ^2- is preferably set to, for example, 30.0% to 80.0%.

In particular, by containing O ^{2 -} 30.0% or more, devitrification of the glass or an increase in the abrasion degree can be suppressed. Therefore, the content of O ^2- is preferably 30.0%, more preferably 40.0%, still more preferably 50.0%, still more preferably 55.0%, and still more preferably 59.0%.

On the other hand, by setting the content of O ² to 80.0% or less, the effect produced by other anionic components can be easily obtained. Therefore, the content of O ^2- is preferably 80.0%, more preferably 75.0%, still more preferably 70.0%, and still more preferably 64.0%.

Further, from the viewpoint of suppressing the devitrification of the glass, the total content of O ^{2 and} the content of F ^- is preferably 98.0%, more preferably 99.0%, and still more preferably 100%.

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 , Mg(PO) ₂ or Ba(PO) ₂ can be used as a raw material.

[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 are described.

In addition to Ti, Zr, Nb, W, La, Gd, Y, Yb, and Lu, the cations of transition metals such as V, Cr, Mn, Fe, Co, Ni, Cu, Ag, and Mo are contained in small amounts, either alone or in combination. In such cases, the glass is also colored and has an absorption property at a specific wavelength in the visible light region. Therefore, it is preferably substantially not contained in the optical glass having a wavelength in the visible light region.

The cations of Pb, Th, Cd, Tl, Os, Be, and Se tend to be controlled and used as harmful chemical substances in recent years, and are required to be taken not only in the manufacturing steps of the glass but also in the processing steps and after the processing of the product. Measures for environmental measures. Therefore, when it is important to pay attention to the influence of the environment, it is preferable to contain substantially no such thing as the inevitable mixing. Thereby, it becomes substantially free from the substance which pollutes an environment in an optical glass. Therefore, the optical glass can be manufactured, processed, and discarded without performing special environmental measures.

The cation of Sb or Ce is useful as an antifoaming agent, but in recent years, there has been a tendency to prevent it from being contained in an optical glass as a component which is disadvantageous to the environment. Therefore, the present invention In this respect, the optical glass preferably does not contain Sb or Ce.

[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 the respective components become within a specific content ratio, and the prepared mixture is poured into quartz crucible or alumina crucible or platinum crucible to be coarsely melted, and then placed. Platinum ruthenium, platinum alloy ruthenium or osmium alloy is melted at a temperature of 900 to 1200 ° C for 2 to 10 hours, stirred and homogenized to defoam, etc., and then cooled to a temperature below 850 ° C, and finally stirred to remove streaks. Recast into the mold for slow cooling.

[physical property]

In the optical glass of the present invention, the maximum value (α _max ) of the linear expansion coefficient in the temperature range between the glass transition point (Tg) and the deformation point (At) is preferably 1500 × 10 ^-7 K ^-1 or less. . Thereby, in particular, even in the case of producing an optical element having a high refractive index and a thin shape, the glass becomes less likely to be broken when subjected to press molding at a temperature higher than the glass transition point, so that the productivity of the optical element can be improved. The reason why the glass is so hard to be broken is, for example, when the glass is softened by heating, or when the softened glass is press-formed and cooled, the inside of the glass is linearly expanded due to the temperature difference inside the glass. a high temperature portion above the glass transition point having a large coefficient and a low temperature portion below the glass transition point having a small coefficient of linear expansion, at which time the thermal expansion or heat shrinkage of the high temperature portion is reduced, thereby causing thermal expansion or heat shrinkage by the high temperature portion. The force applied to the low temperature portion is reduced.

Therefore, in the optical glass of the present invention, the upper limit of the maximum value (α _max ) of the linear expansion coefficient in the temperature range between the glass transition point (Tg) and the deformation point (At) is preferably 1500 × 10 ^-7 K ^{-1 is more} preferably 1300 × 10 ^-7 K ^-1 , still more preferably 1100 × 10 ^-7 K ^-11 , still more preferably 1015 × 10 ^-7 K ^-1 . In particular, in the second optical glass, the upper limit of the maximum value (α _max ) of the linear expansion coefficient may be 960 × 10 ^-7 K ^-1 . On the other hand, the lower limit of the maximum value (α _max ) of the linear expansion coefficient is preferably 500 × 10 ^-7 K ^-1 , more preferably 600 × 10 ^-7 K ^-1 , and further preferably 700 × 10 ^-7 K ^-1 .

Further, in the present specification, the maximum value of the linear expansion coefficient in the temperature range between the glass transition point (Tg) and the deformation point (At) may be simply referred to as "the maximum value of the linear expansion coefficient".

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 1.50, more preferably 1.51, and still more preferably 1.52. The upper limit of the refractive index is preferably 2.00, more preferably 1.90, and still more preferably 1.80.

Further, the optical glass of the present invention preferably has an Abbe number (νd) of 60, more preferably 65, more preferably 70, a lower limit, more preferably 90, still more preferably 85, and still more preferably 80. Upper limit.

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

Therefore, since the optical glass of the present invention is useful in optical design and can realize high precision and thinning of the optical system, the degree of freedom in optical design can be expanded.

Further, the refractive index (nd) and the Abbe number (νd) refer to values measured based on the Japanese Optical Glass Industry Association standard JOGIS01-2003.

The optical glass of the present invention preferably has a high resistance to devitrification (in the description, simply referred to as "devitrification resistance" in the specification). Therefore, since the decrease in the transmittance due to the crystallization of the glass at the time of glass production can be suppressed, the optical glass can be preferably used for an optical element that transmits visible light such as a lens. Further, as a measure indicating that the devitrification resistance at the time of glass production is high, for example, the liquidus temperature is low.

The optical glass of the present invention preferably has a glass transition point of 550 ° C or less. Thereby, since the glass is softened at a lower temperature, the glass can be pressed to a lower temperature. shape. Further, the oxidation of the mold for press forming can be reduced to achieve a longer life of the mold. Therefore, the glass transition point of the optical glass of the present invention is preferably 550 ° C, more preferably 530 ° C, and still more preferably 510 ° C as the upper limit. Further, the lower limit of the glass transition point of the optical glass of the present invention is not particularly limited, and the glass transition point of the optical glass of the present invention is preferably 100 ° C, more preferably 200 ° C, and still more preferably 300 ° C. Lower limit.

Further, the optical glass of the present invention preferably has a deformation point (At) of 650 ° C or less. The deformation point is one of the indexes indicating the softening property of the glass as in the case of the glass transition point, and is an index indicating the temperature close to the press molding temperature. Therefore, by using a glass having a deformation point of 650 ° C or less, press molding can be performed at a lower temperature, so that press molding can be performed more easily. Therefore, the deformation point of the optical glass of the present invention is preferably 650 ° C, more preferably 600 ° C, and most preferably 570 ° C as the upper limit. In particular, in the second optical glass, the upper limit of the deformation point may be 550 °C. Further, the deformation point of the optical glass of the present invention is preferably 150 ° C, more preferably 250 ° C, and still more preferably 350 ° C as the lower limit.

[Preforms and optical components]

A glass molded body can be produced from the produced optical glass by a method of press molding such as reheat press molding or precision press molding. In other words, a preform for press molding can be produced from optical glass, and the preform can be subjected to reheat molding and then subjected to polishing to form a glass molded body, or a preform produced by polishing, or The glass molded body is produced by precision press molding of a preform formed by a known float molding or the like. Furthermore, the method of producing a glass molded body is not limited to these methods.

The glass molded body produced in this manner is useful for various optical components and optical designs. In particular, it is preferable to use a method such as precision press molding to produce an optical element such as a lens or a mirror or a mirror from the optical glass of the present invention. Thereby, when it is used for an optical device that transmits visible light to an optical element such as a camera or a projector, high-precision imaging characteristics and the like can be realized with high precision, and the weight of the optical system in the optical device can be reduced.

[Examples]

The composition of the glass (No. 1 to No. 105) and the comparative example (No. A) of the optical glass of the present invention (indicated by the % of the cation or the % of the anion %), and the refractive index ( The maximum value (α _max ) of nd), Abbe number (νd), glass transition point (Tg), deformation point (At), and linear expansion coefficient are shown in Tables 1 to 16. Among them, Examples (No. 1 to No. 79) are examples of the first optical glass, and Examples (No. 80 to No. 105) are examples of the second optical glass. Furthermore, the following examples are for illustrative purposes and are not intended to be limited to the embodiments.

The optical glasses of the examples and comparative examples of the present invention are produced by selecting oxides, carbonates, nitrates, fluorides, metaphosphoric compounds, etc., which are respectively equivalent to the raw materials of the respective components, and are generally used for the phosphosphate glass. The high-purity raw materials are weighed and uniformly mixed in a ratio of the composition of each of the examples shown in Tables 1 to 16, and then put into a platinum crucible, and the electric furnace is used at 900 to 1200 depending on the degree of melting difficulty of the glass composition. After melting for 2 to 10 hours in the temperature range of °C, the mixture is homogenized and defoamed, etc., and then the temperature is lowered to 850 ° C or lower, and then cast into a mold, and slowly cooled to prepare a glass.

Here, the refractive index and Abbe number of the glass of the examples and the comparative examples were measured based on the Japan Optical Glass Industry Association standard JOGIS01-2003. Further, as the glass used in the measurement, it was treated by a slow cooling furnace under an annealing condition of a slow cooling rate of -25 ° C / hour.

Further, the glass transition point (Tg) and the deformation point (At) of the glass of the examples and the comparative examples were obtained from the thermal expansion curve according to the thermal expansion of the optical glass according to the Japanese Optical Glass Industry Association standard JOGIS08-2003. The measurement method is obtained by measuring the relationship between the temperature and the elongation of the sample.

In addition, the maximum value (α _max ) of the linear expansion coefficient of the glass of the examples and the comparative examples was measured in accordance with the Japanese Optical Glass Industry Association Standard JOGIS 08-2003 "Method for Measuring Thermal Expansion of Optical Glass", and the distance from the glass transition point was determined ( The maximum value of the linear expansion coefficient of every 5 ° C between Tg) and the deformation point (At). The linear expansion coefficient is calculated using the length of the sample at a temperature of a multiple of five.

As shown in Tables 1 to 16, the upper limit of the maximum value (α _max ) of the linear expansion coefficient in the temperature range between the glass transition point (Tg) and the deformation point (At) of the optical glass of the embodiment of the present invention is It is 1500 × 10 ^-7 K ^-1 or less, and more specifically 1020 × 10 ^-7 K ^-1 or less, which is within the required range. On the other hand, the upper limit of the maximum value (α _max ) of the linear expansion coefficient of the glass of Comparative Example (No. A) exceeded 1500 × 10 ^-7 K ^-1 . Therefore, it is clear that the upper limit of the maximum value (α _max ) of the linear expansion coefficient of the optical glass of the embodiment of the present invention is smaller than that of the glass of the comparative example.

Further, the refractive index of the optical glass of the embodiment of the present invention is 1.50 or more, and more specifically 1.52 or more, which is within a desired range. Further, the optical glass of the embodiment of the present invention has an Abbe number of 60 or more, more specifically 72 or more, and the Abbe number is 80 or less, and more specifically 77 or less, which is within a desired range. .

Further, the glass transition point of the optical glass of the embodiment of the present invention is 550 ° C or lower, and more specifically 510 ° C or lower, which is within a desired range.

Further, the deformation point of the optical glass of the embodiment of the present invention is 650 ° C or lower, and more specifically 550 ° C or lower, which is within a desired range.

Therefore, for the optical glass of the embodiment of the present invention, it is clarified that the Abbe number is within a desired range, and has a desired higher refractive index, and the upper limit of the maximum value (α _max ) of the linear expansion coefficient is small. .

Further, since the optical glass of the embodiment of the present invention has a small maximum value of the coefficient of linear expansion, it is less likely to cause breakage of the glass caused by press forming. Therefore, it is presumed that the optical glass of the embodiment of the present invention is less likely to be broken after press forming than the glass of the comparative example.

The present invention has been described in detail above with reference to the exemplifications of the present invention, but the present invention is intended to be illustrative only, and it is understood that numerous changes can be made without departing from the spirit and scope of the invention.

Claims (20)

An optical glass containing P ⁵⁺ 20.0-55.0% and Al ³⁺ 5.0-30.0% as a cationic component based on the molar ratio of the molar ratio, and the content of Ca ²⁺ is 0 to 30.0%, La ³⁺ , Gd The total content of ³⁺ , Y ³⁺ and Yb ³⁺ is Ln ³⁺ is 0 to 0.8 cation %, and the percentage of anion based on the molar ratio is represented by O ^{2 -} 30.0 to 80.0% and F ^- 20.0 to 70.0%. The anion component has a refractive index (nd) of 1.50 or more, and a maximum value (α _max ) of a linear expansion coefficient in a temperature range between a glass transition point (Tg) and a deformation point (At) is 1500 × 10 ^-7 K ^{- 1} or less. The optical glass of claim 1, wherein the content of Sr ²⁺ is 0 to 25.0%, expressed as % of the cation based on the molar ratio. The optical glass of claim 1, which further contains Ca ²⁺ and Sr ²⁺ as a cationic component. The optical glass of claim 1 which contains Ca ²⁺ 0.1 to 30.0% and Sr ²⁺ 0.1 to 25.0% based on the molar ratio of the molar ratio. The optical glass of claim 1, wherein the total content of the P ⁵⁺ content and the Al ³⁺ content is 30.0% or more and 65.0% or less in terms of the cation % based on the molar ratio. The optical glass of claim 1, wherein the content of Ba ²⁺ is 45.0% or less expressed by the percentage of the cation based on the molar ratio. The optical glass of claim 1, wherein the ratio of the Ca ²⁺ content to the Sr ²⁺ content (Ca ²⁺ /Sr ²⁺ ) is 0.50 or more in terms of the cation % based on the molar ratio. The optical glass of claim 1, wherein the total amount of Ca ²⁺ content and Ba ²⁺ content is 10.0% or more and 60.0% or less in terms of the cation % based on the molar ratio. The optical glass of claim 1, wherein the content of Mg ²⁺ is 30.0% or less expressed by the cation % based on the molar ratio. The optical glass of claim 1, wherein the ratio of the Mg ²⁺ content to the Sr ²⁺ content (Mg ²⁺ /Sr ²⁺ ) is 5.00 or less, expressed by the cation % based on the molar ratio. The optical glass of claim 1, wherein the total content of the alkaline earth metal (R ²⁺ ) is from 30.0 to 70.0%, expressed as % of the cation based on the molar ratio. The optical glass of claim 1, wherein the content of Li ⁺ is 10.0% or less, expressed as % of the cation based on the molar ratio. 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 represented by % of the molar ratio based on the molar ratio. 0~10.0%, the content of Yb ³⁺ is 0~10.0%. The optical glass of claim 1, wherein the content of Na ⁺ is 0 to 10.0%, and the content of K ⁺ is 0 to 10.0%, based on the percentage of the cation based on the molar ratio. The optical glass of claim 1, wherein the total content of the alkali metal (Rn ⁺ ) is 20.0% or less, expressed by the cation % based on the molar ratio. The optical glass of claim 1, wherein the content of Si ⁴⁺ is 0 to 10.0%, the content of B ³⁺ is 0 to 15.0%, and the content of Zn ²⁺ is represented by % of cation based on molar ratio. 0~30.0%, the content of Ti ⁴⁺ is 0~10.0%, the content of Nb ⁵⁺ is 0~10.0%, the content of W ⁶⁺ is 0~10.0%, and the content of Zr ⁴⁺ is 0~ 10.0%, the content of Ta ⁵⁺ 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%. . The optical glass of claim 1, which has an Abbe number (νd) of 60 or more. An optical element comprising the optical glass of any one of claims 1 to 17. A preform for polishing processing and/or precision press molding, comprising the optical glass according to any one of claims 1 to 17. An optical component which is precisely pressurized as in the preform of claim 19.